Symposium Organizers
Anis Zribi GE Global Research Center
Changming Li Nanyang Technical University
Larry Nagahara Motorola Labs
Magnus Willander Goeteborg University
E1: Nanoparticles for Biological and Chemical Detection I
Session Chairs
Changming Li
Larry Nagahara
Magnus Willander
Anis Zribi
Monday PM, November 27, 2006
Room 210 (Hynes)
9:00 AM - **E1.1
Using Nanotechnology to Study Basic Aspects and Explore New Phenomena and Applications in Catalysis, (bio)Sensing and Energy Technology.
Hans Fredriksson 1 , Carl Haegglund 1 , Christoph Langhammer 1 , Elin Larsson 1 , Alexandre Dmitriev 1 , Joshua Henry 1 , Michael Zaech 1 , Dinko Chakarov 1 , Igor Zoric 1 , Bengt Kasemo 1
1 Applied Physics, Chalmers University of Technology, Gothenburg Sweden
Show Abstract9:30 AM - E1.2
Conjugated Polymer Particle Systems: Establishing Fidelity and Sensitivity Through Film Architecture for Monitoring Enzyme Activity
Jessica Liao 1 , Timothy Swager 2
1 Materials Science, MIT, Cambridge, Massachusetts, United States, 2 Chemistry, MIT, Cambridge, Massachusetts, United States
Show AbstractConjugated polymers (CP)s have been known to display excellent optical and physical properties amenable for applications in chemical and biological sensing. In particular, CP particles have even greater quantum yields than CPs in solution and a higher propensity for analyte interactions due to increased surface area and the three-dimensionality afforded in the solid state. We have developed a quantitative ratiometric approach for measuring the response of CP particles towards electron-deficient molecules in aqueous environment to understand the role of hydrophobic and electrostatic interactions in our systems. We are also investigating various types of heterostructure assemblies to create assays that demonstrate a high level of sensitivity and selectivity towards complex biological environments. We introduce these as potential substrates for the detection of enzyme activity in critical physiological pathways for use in biomedical imaging.
9:45 AM - E1.3
Nanocomposite Chemical Sensors from Au-nanoparticles and Dendritic Polymers: Sorption Behavior and Electrical Response
Nadejda Krasteva 1 , Yvonne Joseph 1 , Nobuyuki Matsuzawa 2 , Yulia Fogel 3 , Roland Bauer 3 , Klaus Muellen 3 , Akio Yasuda 1 , Tobias Vossmeyer 1
1 Materials Science Laboratory, Sony Deutschland GmbH, Stuttgart Germany, 2 Semiconductor Technology Development Group, Semiconductor Business Unit, Sony Corporation, Atsugi Japan, 3 , Max-Planck Institute for Polymer Research, Mainz Germany
Show AbstractDuring the last decade metal nanoparticle/dendritic polymer composite films have gained remarkable attention as sensitive coatings for chemiresistor sensors. Such materials provide the possibility to exploit the well-established host-guest chemistry of the dendrimers for highly sensitive and selective analyte detection. The sensing properties of these materials can be easily tuned by varying the size, structure, or the composition of the organic component. At the same time, the conductivity of the metal constituent ensures a simple and straightforward electrical signal transduction. Nowadays it is assumed that the chemiresistor responses are mainly determined by the interplay between swelling and changes in the film permittivity caused by analyte sorption. An approach towards a better understanding of the sensing mechanism is to study the sorption behavior of the film to different analytes and correlate it with the electrical response of the respective chemiresistor device. In this contribution we report on the vapor sensing properties of AuPPh films built of Au-nanoparticles and 1st and 2nd generation dithiolane terminated polyphenylene dendrimers (PPh). The films were deposited onto transducer substrates via layer-by-layer self-assembly and characterized by AFM and XPS. Their sorption behavior was determined by measuring the uptake of analytes with quartz crystal microbalances (QCM). Simultaneously the resistance of the films deposited onto electrically addressable substrates was monitored. Toluene, 1-propanol, tetrachloroethylene (TCE) and water were used to generate vapors of analytes with different polarity, which allowed studying the structure-response relationship in the AuPPh system. Both sensor types, QCMs and chemiresistors, gave qualitatively very similar response isotherms, which were in agreement with a combination of Henry- and Langmuir-type sorption. The relative sensitivity of the films to different solvents decreased in the order toluene ~ TCE > 1-propanol >> water. Films comprising the larger 2nd generation dendrimers showed higher sensitivity than those comprising 1st generation dendrimer. The sorption-induced increase in film resistance scaled linearly with the amount of analyte sorbed in the films. This result is in general agreement with an activated tunneling process for charge transport if only little swelling and only small permittivity changes occur during analyte exposure. The response of the films to equal uptake of analytes decreases with increasing the dielectric constant of the analyte. This trend is qualitatively in agreement with the assumption that an analyte induced increase in the permittivity of the organic component in the film may reduce the energy barriers for charge transport and thus may counteract the increase in resistance due to film swelling.
10:00 AM - E1.4
The Detection of Pathogens with Modified Silica Particles on Paper
Michael Brook 1 2 , Rebecca Voss 1 , Jordan Thomson 1 , Yang Chen 1 , Robert Pelton 2 1 , John Brennan 1
1 Chemistry, McMaster University, Hamilton , Ontario, Canada, 2 Chemical Engineering, McMaster University, Hamilton, Ontario, Canada
Show AbstractThere is a general need for rapid remediation of pathogen containing waters, for example, after severe storms or flooding. Paper provides a cost effective, high surface area substrate that can be used to support bioactive entities that detect and kill pathogens. Silica is widely used in paper coating processes to modify surface properties and, using this paradigm, we are developing pathogen-detecting/destroying silica particles for coating onto paper. Spherical silica particles were prepared from diglycerylsilane in a one step biocompatible process that allows the incorporation of ‘detectors’ during silica synthesis into the center of the particle, where they are protected from the external environment. A variety of conditions and additives were employed to ensure stability of more sensitive detectors, like proteins or enzymes. A prototypical particle uses one of several commercially available systems to detect biologically relevant molecules, such as adenosine tri-phosphate (ATP), which are released from cells during lysis. These systems could be based on either inorganic-organic complexes, proteins or aptamers. As an example, pyrochatecol violet ytterbium complex modified particles were stable to repeated washing cycles and showed the expected change in color when exposed to their small target molecule ATP. Capture molecules for specific pathogens were anchored to the surface of the silica spheres using poly(ethylene oxide) as a spacer. To achieve this, a biofunctional coupling agent, prepared from monoallyl ethers of PEO, was grafted to silica through Si(OEt)3 groups and to the capture molecules through an NHS group. The PEO was important to maintain protein stability on the silica surface. This combination of specific binding of pathogens and detection of lyses of the bound entities, leading to the release of ATP as a target for the detector within the silica is an effective way to evaluating the presence of selected water borne pathogens. The focus of the talk will be the characteristics of the different components needed to realize such a device: including the preparation of the particles under different conditions; their efficiency as ‘detectors’ for small biologically relevant molecules; and their ability to bind to specific pathogens.
10:15 AM - E1.5
Metallothioneins Deplete Surface Cations from and Mediate Toxicity of Semiconducting Nanoparticles.
Baikuntha Aryal 1 , Marinella Sandros 1 , Kosh Neupane 1 , David Benson 1
1 Department of Chemistry, Wayne State University, Detroit, Michigan, United States
Show Abstract10:30 AM - E1.6
Synthesis, Characterization and Cytotoxicity of FePt@CoS2 Yolk-shell Nanocrystals.
Jinhao Gao 1 , Gaolin Liang 1 , Bei Zhang 3 , Xixiang Zhang 3 , Bing Xu 1 2 4
1 Department of Chemistry, The Hong Kong University of Science & Technology, Hong Kong, NA, Hong Kong, 3 Department of Physics, The Hong Kong University of Science & Technology, Hong Kong Hong Kong, 2 Bioengineering Program, The Hong Kong University of Science & Technology, Hong Kong Hong Kong, 4 Center of Cancer Research, The Hong Kong University of Science & Technology, Hong Kong Hong Kong
Show AbstractRecently, Yin et al. reported the use of Kirkendall effect as a general and effective strategy to produce yolk-shell nanostructures (Science 2004, 304, 711-714), but the potential biological properties of these types of materials have yet to be explored. Here we reported cytotoxicity of the synthesized FePt@CoS2 yolk-shell nanomaterials. We used a one-pot method to make FePt@CoS2 yolk-shell nanostructures by a mechanism analogous to Kirkendall effect. Using FePt nanoparticles as the seeds, we synthesized FePt@Co core-shell nanostructures by adding Co2(CO)8 into a refluxing organic solution. Then the cobalt shell reacted with sulfur powder in solution to give the FePt@CoS2 yolk-shell nanostructures, which were characterized by means of high-resolution transmission electron microscopy, energy dispersive X-ray spectrometer, selected area electron diffraction, and X-ray photoelectron spectroscopy. The cytotoxicity of the synthesized FePt@CoS2 yolk-shell nanomaterials was evaluated by MTT assay. The cellular uptake of nanostructures was detected by TEM and confirmed magnetic properties analysis (SQUID), which prove that the FePt nanoparticles were released from the nanostructure to cytoplasma after cellular uptake. The IC50 (for HeLa cell lines) of the FePt@CoS2 nanomaterials (35.5±4.7 ng Pt/mL) is much lower than that of cisplatin (230 ng Pt/mL). Moreover, FePt@CoS2 nanomaterials exhibit bacterial inhibition ability, with the MIC value (against Gram positive strain, Bacillus) of FePt@CoS2 nanomaterials is ~10 μg/mL. These results suggest the yolk-shell nanostructure is a useful lead for exploring nanomedicine to treat cancer or bacteria infections.
10:45 AM - E1.7
Nanostructured Particles for the Treatment of Bone Diseases
Ganesan Balasundaram 1 , Thomas Webster 1
1 Engineering, Brown University, Providence, Rhode Island, United States
Show Abstract12:00 PM - E1.9
Functionalisation of Calcium Phosphate Nanoparticles by Oligonucleotides and their Application for Gene Silencing.
Viktoriya Sokolova 1 , Anna Kovtun 1 , Oleg Prymak 1 , Wolfgang Meyer-Zaika 1 , Elena Kubareva 2 , Elena Romanova 2 , Tatiana Oretskaya 2 , Rolf Heumann 3 , Matthias Epple 1
1 Institute of Inorganic Chemistry, University of Duisburg-Essen, Essen Germany, 2 Department of Chemistry and A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow Russian Federation, 3 Chair of Biochemistry, Molecular Neurobiochemistry, University of Bochum, Bochum Germany
Show AbstractIn molecular biology, the production of proteins can be effectively inhibited by introducing specific oligonucleotides into a living cell (gene silencing or antisense strategy; important for gene therapy). Calcium phosphate nanoparticles can serve as carriers for biomolecules in such therapeutic applications due to their high biocompatibility and good biodegradability. Stable colloids were prepared by coating the inorganic nanoparticles with single- and double-stranded oligonucleotides. The properties of the colloidal dispersions can be adjusted by variation of the oligonucleotide concentration. The dispersions were analysed by dynamic light scattering, zeta potential measurements, transmission electron microscopy, and scanning electron microscopy. Particles with a diameter of about 100 nm were obtained under optimized conditions. The efficiency of such nanoparticles to specifically inhibit protein synthesis was tested on HeLa-EGFP cells whose green fluorescence was turned off by the coated nanoparticles (gene silencing with siRNA). The dispersions are stable and can be stored at 4 °C without loss of activity for several weeks, making them available as biochemical reagents.
12:15 PM - E1.10
Quantum Dot Assisted Intracellular Trafficking Of Non-Viral Gene Delivery Vectors.
Charudharshini Srinivasan 1 , Jeunghoon Lee 2 , Fotios Papadimitrakopoulos 2 , Lawrence Silbart 3 , Diane Burgess 1
1 Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut, United States, 2 Nanomaterials Optoelectronics Lab, Polymer Program, Department of Chemistry, Institute of Materials Science, University of Connecticut, Storrs, Connecticut, United States, 3 Department of Animal Science, Center of Excellence for Vaccine Research, University of Connecticut, Storrs, Connecticut, United States
Show Abstract12:30 PM - E1.11
Unique Optical and Physical Properties of Surface-modified Nanocrystalline Zinc Oxide.
Jason Soares 1 , Diane Steeves 2
1 Macromolecular Science Team, US Army RDECOM - Natick Soldier Center, Natick, Massachusetts, United States, 2 Nanomaterials Science Team, US Army RDECOM - Natick Soldier Center, Natick, Massachusetts, United States
Show Abstract12:45 PM - E1.12
Gas Sensing Properties of Hexagonal Tungsten Oxide Nanoparticles.
Lisheng Wang 1 , Perena Gouma 1
1 Materials Science and Engineering, Stony Brook University, Stony Brook, New York, United States
Show AbstractE2: Nanoparticles for Biological and Chemical Detection II
Session Chairs
Monday PM, November 27, 2006
Room 210 (Hynes)
2:30 PM - E2.1
Water-soluble Pegylated Quantum Dots: From Composite Hexagonal Phase to Isolated Micelles.
Boulmedais Fouzia 1 3 , Artzner Franck 2 , Dahan Maxime 4 , Marchi-Artzner Valerie 1
1 Chemistry department, CNRS, UMR 6226, Rennes France, 3 CNRS, UPR22, Institut Charles Sadron, Strasbourg France, 2 Physics Department, CNRS, UMR 6626, Rennes France, 4 Physics department, , Laboratoire Kastler Brossel, CNRS UMR 8552, Paris France
Show Abstract2:45 PM - E2.2
Ultra-Bright Fluorescent Silica Particles: Self-Assembly and Possible Use for Sensing.
Sajo Naik 2 , Jason Kaszpurenko 2 , Igor Sokolov 1
2 Physics, Clarkson University, Potsdam, New York, United States, 1 Physics, Chemistry, Clarkson University, Potsdam, New York, United States
Show AbstractFluorescent particles have a broad application in tagging, tracing, and labeling. Fluorescence is typically made through incorporating either inorganic or organic fluorescent dyes into carrier matrix material. While inorganic dyes are typically more stable, their number and compatibility is rather restricted. A large variety of organic dyes makes them attractive for creating fluorescent particles. However the problems are in the dye stability and typically its high toxicity. Incorporation of dyes into silica matrix seems to be one of most promising approaches because of excellent sealing ability of silica and wide compatibility of silica with other materials. Numerous attempts to embed organic dyes into silica xerogels and zeolites have been known for long time. To prevent leakage of the dyes out of the porous matrix, dyes were covalently bound to the silica matrix. While photostability of such materials was higher than stability of pure dyes, it did not prevent bleaching substances, including oxygen, from penetration inside such a composite material. Furthermore, it is rather hard to use xerogels for labeling. Recently there have been several reports about incorporation of fluorescent lasing dyes into mesoporous patterned silica films and silica roads. Here we describe a novel synthesis of one-step self-assembly of mesoporous silica particles with encapsulated organic dyes. We also demonstrate encapsulation of a mixture of different dyes in single silica particles. Dyes are physically encapsulated inside nanosize channels/tubes in micron size particles. Particles of such size can be of particular use a number of applications, including flow cytometry, labeling of skin-care products. Encapsulation manifests itself in virtually no leakage of the dyes out of the particles. High concentration of the fluorescent dyes can be reached inside the pores without dimerization of the fluorescent molecules. This results in up to ~500 time brighter fluorescence of than from the corresponding dye at maximum concentration (just before dimerization, self-quenching). This makes these particels to be brighter than similar volume of silica coated quantum dots. Fluorescence of the assembled particles is very stable. Using appropirate dyes, these particles can also be used for sensing of various chemical and phyical properties. Several examples will be presented.
3:00 PM - E2.3
Surface Modification of Rare-Earth Doped Ceramic Nano-Phosphors for Fluorescence Bio-Imaging
Kohei Soga 1 , Yu Saito 1 , Kazuaki Shimizu 1 , Hiroyasu Nagata 1 , Tomoya Konishi 1 , Yukio Nagasaki 2
1 Materials Sci. and Tech., Tokyo Univ. of Science, Noda, Chiba, Japan, 2 Tsukuba Res. Ctr. Interdisciplinary Mat. Sci., Univ. of Tsukuba, Tsukuba, Ibaraki, Japan
Show AbstractFluorescence bio-imaging is a method to visualize the phenomena in bio systems, which is one of the key technologies in biological and medical research fields. Most important problem of current bio-imaging system using organic dyes or proteins is a color fading due to the UV-VIS excitation light for the fluorescence. Bio imager using quantum dots are attractive fluorescent probes without color fading, though their preparation is not easy with fine size control and without quenching by defects or chemical corrosion. The authors have been proposing rare-earth doped ceramic nano-phosphors for bio-imaging. Namely, the phosphors exhibits IR-to-VIS upconversion emission are attractive since one can use IR for the excitation. The IR excitation light gives less damage to the bio system and is less scattered due to its long wavelength compared to the UV or VIS. The ceramic phosphors are basically non-bio functional. For bio-imaging, at least functions as specific adsorption to a certain part of bio systems, prevention of non-specific adsorption to the other parts of the system and mono dispersion in high concentration electrolytic solution, such as phosphoric buffer saline. Those functions can be given to the ceramic phosphors by surface modifications by bio-functional polymers. In the present study, erbium-doped yttira nano-particles are used as upconversion emissive nano-particles. Several routs for preparing mono-dispersed yttria nano-particles in water solution will be reported. Also, surface modification routs by electrostatic or covalent bonding of bio-functional polymers on the ceramic surface will be reported.Poly(acrylic acid) (PAAC) is a polymer that can modify the surface of the yttria nano-particles. We reported that the PAAC can be firmly electrostatically adsorbed on the yttria surface since the surface charge of the yttria is known to be positive [1]. Also, the PAAC modification changes the surface charge of the particle into negative and helps the connection to positively charged end of bio-functional polymers. The yttria nano-particles can easily be agglomerated in high concentration electrolytic solution and dissolved into acidic solutions. The dispersion and chemical durability of the PAAC modified yttria nano-particles are investigated in this study. The PAAC modification obviously improved the dispersion and chemical durability.[1] Kohei Soga, Ryo Koizumi, Masayoshi Yamada, Daisuke Matsuura and Ykio Nagasaki, “Preparation of Polymer Composite Upconversion Phosphor from Inorganic Particle,” J. Photopolymer Sci. and Tech., 18 [1] (2005) 73-74.
3:15 PM - E2.4
Optically Switchable Nanoparticles For Biological Imaging
Alex Li 1
1 Chemistry, Washington State University, Pullman, Washington, United States
Show AbstractApplication of nanoparticles in bio-medical imaging has attracted great attention because nanoparticles have distinct advantages, such as ultra bright emission and tunable of fluorescence color. To positively identify the biological labeled site, verify the presence of multiple species at a single site, and control trafficking in biological systems, it is desirable to confirm the presence of target nanoparticles rather than false positives or cell autofluorescence. Accordingly, we have developed nanoparticles whose fluorescence color can be photoswitched. Two separate approaches will be discussed: one is based on polymeric materials and the other on hybrid inorganic and organic materials.First, emulsion polymerization yields 40-400 nm diameter polymer nanoparticles with “on” and “off” fluorescence switching properties upon alternating UV and visible light excitations. The photophysical characteristics of the encapsulated fluorophores differ dramatically from those of the same species in solution, making nanoparticle-protected hydrophobic fluorophores attractive materials for potential applications such as optical data storage and switching and biological fluorescent labeling. To evaluate the potential for biological tagging, these optically addressable nanoparticles have been delivered into living cells and imaged with a liquid nitrogen cooled CCDSecond, spiropyran dyes were attached to fluorescent core-shell CdSe/ZnS nanocrystals via thiol-containing linker groups. Photoisomerization of the dye to its merocyanine form by UV irradiation caused a dramatic loss in the intrinsic nanoparticle fluorescence, which was regained upon reversing the isomerization with visible light. The fluorescence quenching efficiency increased with increasing spectral overlap of fluorescence emission and merocyanine adsorption bands, consistent with FRET as the quenching mechanism. Typically, complete quenching required at least 80 bound dye molecules per particle.
3:30 PM - E2: nParticle-2
Break
4:30 PM - **E2.5
Wet-Chemical Routes to the Preparation of Nanomaterials and Self-Assembly-Based Fabrication of Novel Structures.
Shaojun Dong 1
1 State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Changchun, Jilin, China
Show AbstractBoth the wet-chemical preparation of nanomaterials and self-assembly-based fabrication of novel structures have been paid considerable attention. We carried out several studies on the preparation of noble metal nanoparticles and its two-dimensional nanostructures and conducting polymers nanobelts via wet-chemical routes. On the other hand, we fabricated some novel structures through self-assembly on planar solid substrates or in solutions. We obtained some new results in following aspects:(1)We have presented a heat-treatment-based strategy for the one-step preparation of size-controlled, dendrimer-protected gold nanoparticles, carried out by directly heating an aqueous solution containing dendrimer and HAuCl4 without the additional step of introducing other reducing agents and protective agents. (2)We have reported a novel but simple templateless, surfactantless route to the large scale and rapid synthesis of uniform poly(o-phenylenediamine) nanobelts by directly mixing HAuCl4 and o-phenylenediamine aqueous solutions at room temperature without the additional introduction of other templates or surfactants. (3)We have developed several wet-chemical approaches for the large-scale preparation of single-crystalline gold two-dimensional structures including nanoplates and microdisks.(4)We have prepared submicrometer-scale, monodisperse, spherical colloids of coordination polymers, based on the coordination-induced self-assembly of PtCl62- and p-phenylenediamine in solutions.(5)We have developed a method for effective immobilization of Ru(bpy)32+ on sulfhydryl-derivated electrode surfaces. (6)We have demonstrated that heating a H2PtCl6/3-thiophenemalonic acid aqueous solution gives small Pt nanoparticles and the following treatment of such particles with Ru(bpy)32+ in aqueous solution causes the assembly of such particles into aggregates. (7)We have demonstrated the preparation of morphology-controlled Ru(bpy)32+-containing microstructures exhibiting excellent ECL behaviors via solution-based ionic self-assembly, carried out by directly mixing H2PtCl6 and Ru(bpy)3Cl2 aqueous solutions at room temperature.
5:00 PM - E2.6
Highly Efficient Luminescent Nanomaterials viaMicrowave-assisted Synthesis in Ionic Liquids.
Claus Feldmann 1 , Gunnar Buhler 1
1 Institute for Inorganic Chemistry, University of Karlsruhe, Karlsruhe Germany
Show Abstract5:15 PM - E2.7
Studies on Designing Luminescent virus Like Particles as Possible Biosensors.
Suraj Dixit 1 , Bogdan Dragnea 1
1 Chemistry, Indiana University , Bloomington, Indiana, United States
Show Abstract5:30 PM - E2.8
Study on the Photocatalytic Activity of Nanocrystalline Coupled Catalysts in Immobilized Form.
Roberto Comparelli 1 , Michela Corricelli 1 , Annamaria Panniello 1 , Maria Lucia Curri 1 , Angela Agostiano 1 2 , Antonio Licciulli 3 , Giuseppe Mascolo 4
1 IPCF, CNR , Bari Italy, 2 Department of Chemistry, University of Bari, Bari Italy, 3 Department of Engineering, University of Lecce, Bari Italy, 4 IRSA, CNR, Bari Italy
Show Abstract5:45 PM - E2.9
The Effect of Titanium Dioxide Nanoparticle on the Damage of DNA with UV Irradiation.
Bingquan Li 1 , Wilson Lee 2 , Yue Wang 3 , Eli Hatchwell 3 , Jonathan Sokolov 1 , Miriam Rafailovich 1
1 materials science, stony brook university, stony brook, New York, United States, 2 , Estee Lauder Corp., Melville, New York, United States, 3 , Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States
Show AbstractE3: Poster Session: Nanoparticles for Biological and Chemical Detection
Session Chairs
Changming Li
Larry Nagahara
Magnus Willander
Anis Zribi
Tuesday AM, November 28, 2006
Exhibition Hall D (Hynes)
9:00 PM - E3.1
DNA Hybridization Detection using Fluorescent Zinc Selenide Quantum Dots.
Jun Wang 1 , Tracy Heckler 1 , Qi (Grace) Qiu 1 , Stelios Andreadis 2 , Triantafillos Mountziaris 1
1 Chemical Engineering, University of Massachusetts, Amherst, Massachusetts, United States, 2 Chemical and Biological Engineering, University at Buffalo - SUNY, Amherst, New York, United States
Show AbstractFluorescent labeling of biomolecules is used widely for analytical purposes in biotechnology. It typically involves the use of an organic dye linked to a moiety that selectively bonds a particular molecule, allowing the detection of the latter by the fluorescence of the dye. Semiconductor quantum dots are a new class of fluorescent markers with distinct advantages over traditional organic dyes. Their attractive properties include narrow emission with size-tunable wavelength, continuous excitation by any wavelength smaller than the emission wavelength, resistance to photobleaching, and excellent optical and chemical stability. This work focuses on the development of DNA analysis tools using fluorescent quantum dots. ZnSe quantum dots are synthesized in a hot coordinating solvent by injecting suitable precursors. The synthesis is carried out in a stirred batch reactor containing liquid hexadecylamine at 260 degrees C. The precursors are diethylzinc diluted in heptane, and selenium powder dispersed in trioctylphosphine. The time of reaction is used to control the size and emission wavelength of the quantum dots. Capping of the ZnSe quantum dots with a ZnS layer to obtain core-shell structures enhanced their quantum yield and stability.Water-dispersible fluorescent ZnSe quantum dots are formed by using surface ligand exchange reactions with mercapto-carboxylic acid. The resulting quantum dots are stable in aqueous solutions and luminescent over a period of several days, thus suitable for biological sensing applications. Conjugation of water-dispersible ZnSe and (ZnSe)ZnS quantum dots with oligonucleotides was found to increase their fluorescence emission intensity up to a factor of five. Quantum dots conjugated with longer DNA strands exhibited stronger fluorescence emission intensity than the ones conjugated with shorter strands, with saturation at about 50 bases. The stability of quantum dots in water was enhanced after conjugation with oligonucleotides. Detection of DNA hybridization was studied in aqueous solutions using quantum dots functionalized with oligonucleotides. Experiments were performed pairing quantum dots functionalized with complementary oligonucleotides to study hybridization. Other experiments aimed to study DNA hybridization between quantum dots functionalized with oligonucleotides and free oligonucleotides in solution. Upon hybridization, a measurable increase in the fluorescence intensity of the quantum dots was detected accompanied in some cases by a measurable red shift in the wavelenght of the fluorescence peak. Applications of these phenomena in novel DNA detection strategies will be presented. Ongoing experiments in our laboratory aim to develop multiplexed DNA probes employing quantum dots emitting at different wavelengths.
9:00 PM - E3.12
A Novel Method To Prepare Cysteine Capped Cadmium Selenide Nanoparticles
Oluwatobi Oluwafemi 1 , Neerish Revaprasadu 1
1 Chemistry, University of Zululand, Kwadlangezwa, Kwa-zulu Natal, South Africa
Show AbstractRecently, biosynthesis and biological surface modification of semiconductor and metal nanoparticles with biomolecules such as proteins and nucleic acids have added a new dimension to research in nanodimensional materials.1-5 The conjugation of nanoparticles with biological molecules represents convolution of nanotechnology and biotechnology where novel hybrid materials can be synthesized by incorporating the unique optical and electronic properties of nanoparticles and highly selective binding of proteins and oligonucleotides. With this application in mind, highly water soluble and biocompatible L-cysteine-capped CdSe nanoparticles have been synthesized in a protic solvent for the first time by a novel method without using any additional stabilizer. The cysteine capped CdSe particles have a narrow size distribution and fluoresce in the blue region thereby establishing the possibility of using these as fluorescent biological probes The synthesis involves a reaction of selenium powder with sodium borohydride (NaBH4) to produce selenide ions which act as the source of selenium, followed by addition of cadmium chloride and L-cysteine ethyl ester hydrochloride. The nanoparticles were characterized by optical spectroscopy, IR, x-ray diffraction and electron microscopy. FTIR study shows that CdSe nanoparticles are capped through mercapto-group of cysteine amino acid. while its free amino and carboxylate groups make it amenable to bio-conjugation The nanoparticles formed exhibit good crystallinity and the average particle size as extimated by the UV lies in the size quantization regime which is in agreement with the TEM and XRD analysis. References1)A. Chatterjee, A. Priyam, S.K. Das and Abhijit Saha, Journal of colloidal and interface science,294,(2006),334 2)S. Wang, N. Mamedova, N.A. Kotov, W. Chen and J. Studer, Nano Letter. 2 (2002),817 3)A. Shroedter, H. Weller, R. Eritja, W.E. Ford and J.M. Wessels, Nano Letter. 2, (2002),1363. 4)A. Ahmad, S. Senapati, M.I. Khan, R. Kumar and M. Sastry, Langmuir 19, (2003),3550.5)Y. Xiao, F. Patolsky, E. Katz, J.F. Haintfeld and I. Willner, Science, 299,(2003),1877
9:00 PM - E3.13
Chemical Aspects of Place Exchange Reactions
Adil Kassam 1 , Elisa Fuller 1 , Jeff Shepard 1 , Bruce Lennox 1
1 Chemistry, McGill, Montreal, Quebec, Canada
Show AbstractContinuing on our previous work of mechanism and kinetics of place exchange reactions(PERs)[1], we have used gold nanoparticles(AuNPs) with different lengths of alkylthiol on both the AuNPs and in solution. These results confirm our earlier work, that the limiting step of PERs is dissociation from the Au surface. Additionally we have used particles of different sizes as well as disulphides to elucidate further aspects of the reaction. These results lead to a convergent picture of both kinetics and mechanism of the reaction.1.Place Exchange Reactions of Alkyl Thiols on Gold NanoparticlesKassam, A., Bremner, G., Clark, B., Ulibarri, G., and Lennox, R.B.J. Am. Chem. Soc., 128, 11, 3476 - 3477, 2006, 10.1021/ja057091q
9:00 PM - E3.14
One-pot Synthesis of highly-conductive In2O3:Sn (ITO) Nanocrystals.
G. Buehler 1 , D. Tholmann 2 , Claus Feldmann 1
1 , University of Karlsruhe, Karlsruhe Germany, 2 , Degussa AG , Marl Germany
Show Abstract9:00 PM - E3.15
Nanoparticle-based Biodetection: Enhanced Performance by Exploiting Nanoparticle-Biomolecule Interactions.
Chunhai Fan 1 , Shiping Song 1 , Lihua Wang 1
1 , Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai China
Show Abstract9:00 PM - E3.16
Preparation and Characterization of Core/shell type Ag/SiO2 Nanocapsules.
Young Soo Kang 1 , Hwa Jin Cha 1 , Young Hwan Kim 1
1 Chemistry, Pukyong National Univ., Pusan Korea (the Republic of)
Show Abstract9:00 PM - E3.17
TiO2 Nanoparticles for Gas Sensing: Experimental Measurements and Theoretical Calculations to Determine Correlations between Particle Size and Sensitivity.
Elvin Beach 1 , Patricia Morris 1 , Wolfgang Windl 1
1 Materials Science & Engineering, The Ohio State University, Columbus, Ohio, United States
Show AbstractA substantial amount of recent research in the field of gas sensing has focused on metal-oxide nano-morphologies (particles, wires, etc.) to increase the sensitivity to trace levels of gases and decrease response times [1-3]. Metal-oxides are of particular interest due to their unique surface properties enabling sensitivity to a range of gas species [4]. The concept that reducing particle diameter to less than twice the width of the depletion region (Debye Length) on the surface of the particles results in improved sensitivity [5, 6] is the motivation for this study. The work presented here examines the relationships between particle size, sensitivity to various gas species and response time for titanium dioxide (TiO2) nanoparticles. Crystalline (anatase) TiO2 nanoparticles were fabricated using a low temperature, solvothermal technique that requires no subsequent high temperature processing [7]. Variables such as precursor concentration, temperature and reaction time were altered to produce nanoparticles of varying sizes. TiO2 particles as small as 5nm are fabricated using this method. Particle size, morphology, and crystal structure were characterized by transmission electron microscopy (TEM), dynamic laser light scattering (DLS), x-ray diffraction (XRD) and surface area measurements. Thin films of TiO2 nanoparticles were deposited from solution on substrates with integrated electrodes for gas sensing measurements. The sensitivity and response times to gas species such as CO and O2 were measured for the resulting sensors. Theoretical calculations of the Debye length are performed at different levels of theory to benchmark the observed results with predictions from simulation. We use density-functional and density-functional perturbation theory for our atomic-level calculations to calculate dielectric constant and ionic strength, which are necessary to calculate a theoretical Debye length. TiO2 nanoparticles with sizes ranging from less than twice the Debye length to particle sizes much larger than this have been fabricated via a simple solvothermal process. The relationships between particle size, microstructure, sensitivity and response time were examined. Correlations between the measurements and those predicted from simulation are discussed.References1.F. Cosandey, G.S., A. Singhal, JOM-e, 2000. 52(10).2.Blaser, G.,Physica A: Statistical and Theoretical Physics, 1999. 266(1-4): p. 218-223.3.C. Martinez, B.H., C. Montgomery, S. Semancik, Langmuir, 2005. 21(17): p. 7937-7944.4.Comini, E., Analytica Chimica Acta, 2006. 568(1-2): p. 28 - 40.5.Korotcenkov, G., Sensors and Actuators B, 2005. 107: p. 209-232.6.M. Franke, T.K., U. Simon, Small, 2006. 2(1): p. 36-50.7.M. Niederberger, M.B., G. Stucky, Chemical Materials, 2002. 14(10): p. 4363-4370.
9:00 PM - E3.18
Synthesis of Au Nanocrystal-embedded TiO2 Nanoparticles by Microemulsion Methods.
Hee-Man Yang 1 , Kwang-Suk Jang 1 , Jong-Duk Kim 1
1 , KAIST, Daejeon Korea (the Republic of)
Show Abstract9:00 PM - E3.19
Interfacial Functionalization of Core@shell Iron Oxide@gold Nanoparticles Towards Bio-conjugate Nanoscale Magnetic Labels for Biochip Based on Immunoassays.
Hye-Young Park 1 , Chuan-Jian Zhong 1
1 Chemistry, State University of New York at Binghamton, Binghamton, New York, United States
Show AbstractThe ability to manipulate nanoscale optical and magnetic properties is important for creating spectroscopic nanoprobes useful for biochip based on immunoassay applications. One advantage of such nanoprobes is that the sensitivity of immunoassays can be greatly increased by concentrating the target analyte using the magnetic properties. This presentation describes the synthesis of water-soluble sore@shell iron oxide@gold nanoparticles with high controlled sizes and high monodispersity and their application in biochip based on immunoassays. The core@shell iron oxide@gold nanoparticles were synthesized in organic phase and then transferred to aqueous solution by applying fine-tunable thiol-gold chemistry. The viability of labeling the water-soluble core@shell particles with the desired antibodies was investigated. The thiolate-based surface immobilization on the gold shell (e.g., reporter molecules for surface-enhanced Raman scattering) serves as the spectroscopic signature for chemical or biological identification and quantification, whereas the interfacial binding specificity relies on antigen-antibody interactions. The integrated performance of this assay scheme for the detection of protein molecules will be discussed. Findings from experiments designed to optimize the labeling conditions including solution, pH, ionic strength, and the use of surfactant will also be discussed.
9:00 PM - E3.2
Encapsidation of Gold Nanoparticles by Alphavirus-like Nucleocapsids.
Nancy Goicochea 1 , Suchetana Mukhopadhyay 2 , Bogdan Dragnea 1
1 chemistry, indiana university, Bloomington, Indiana, United States, 2 Biology, Indiana University , Bloomington, Indiana, United States
Show Abstract9:00 PM - E3.20
Preparation and Characterization of Ag Nano-sieve using 1,3,5-benzenetricarboxylic Acid.
Young Soo Kang 1 , Young Hwan Kim 1 , Chang Woo Kim 1 , Hyun Gil Cha 1 , Xiao-Li Zhang 1
1 Chemistry, Pukyong National Univ., Busan Korea (the Republic of)
Show Abstract9:00 PM - E3.21
A Solvothermal Route to Multilayer Coatings on Silica Spheres: Study of Optical and Magnetic Properties.
Dipan Kundu 1 , Ravishankar Narayanan 1
1 Materials Research Centre, Indian Institute of Science, Bangalore India
Show Abstract9:00 PM - E3.22
Facile Preparation Route for Thermosensitive Organo Silica Particles
Ha Young Kim 1 , Chan Yoon Jung 1 , Sang Man Koo 1
1 Department of Chemical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractTrimethoxy(octadecyl)silane (OTS) based particle and their composite particles with vinyltrimethoxysilane (VTMS) or tetraethyl-orthosilicate (TEOS) were synthesized using a alcohol solvent under basic condition. The result of XRD, applying Bragg’s Law, gives d spacing of 4.1 Å, which would be a quite close to lamellar layer structure. The major weight losses of OTS based particles under N2 atmosphere occurred between 400 and 600 degrees, due to the decomposition of octadecyl group, while those of same particles in air was observed between 200 and 600 degrees, giving the residual yield of 18 %. The DSC profile of OTS based particle showed the melting temperature around at 58 degrees, while the melting point of OTS/VTMS composite particle was about 10 degrees lower than that of OTS based particles. In the other hand, the melting point of OTS/TEOS composite particle could not be found. The morphological property of resulting particles was characterized by the transmission electron microscopy (TEM) and the field emission scanning electron microscopy (FE-SEM).
9:00 PM - E3.23
Synthesis and Characterization of Tunable and Highly Transparent Thick Layers of Nanocomposites Based on Methacrylates and Silica Nanoparticles
Giuseppina Simone 1 2 3 , Gerardo Perozziello 1 , Vincenzo Tagliaferri 2 3 , Nicolas Szita 1
1 Department of Micro- and Nanotechnology, Technical University of Denmark, Kgs. Lyngby Denmark, 2 Department of Mechanics and Aeronautics, University of Rome “La Sapienza”, Rome Italy, 3 Department of Mechanical Engineering, University of Rome “Tor Vergata”, Rome Italy
Show Abstract9:00 PM - E3.24
An Investigation on the Process of Digestive Ripening of Metal Nanoparticles.
Bratindranath Mukherjee 1 , Ravishankar Narayanan 1
1 Materials Research Centre, Indian Institute of Science, Bangalore India
Show Abstract9:00 PM - E3.25
Synthesis of Highly Porous Metal Nanoparticles
Aditi Halder 1 , Ravishankar Narayanan 1
1 Materials Research Centre, Indian Institute of Science, Bangalore India
Show Abstract9:00 PM - E3.26
Laser Deposited Ag3SbS3 and Tl3SbS3 Nanoscale Thin Films as Potential Electric Field Sensors.
Halyna Khlyap 1 , Lyudmila Panchenko 2
1 Physics, University of Technology, Kaiserslautern Germany, 2 Physics, State University, Sumy Ukraine
Show Abstract9:00 PM - E3.27
Fe3O4-Au Dumbbell Nanoparticles for Targeted Delivery of Platin-like Therapeutic Agents
Chenjie Xu 1 , Jin Xie 1 , Chao Wang 1 , Shouheng Sun 1
1 Chemistry, Brown University, Providence, Rhode Island, United States
Show AbstractThe selective delivery and controlled release of therapeutic agents, such as cisplatin, cis-Pt(NH3)2Cl2, and its analogues, to malignant tissues constitute one of the greatest challenges in cancer research. Here we introduce Fe3O4-Au dumbbell nanoparticles as a potential vector to transport platin-like anticancer drugs into cancel cells and cell nucleus. The dumbbell nanoparticles are synthesized by thermal decomposition of iron pentacarbonyl on the surface of Au nanoparticles followed by air oxidation. The hydrophobic nanoparticles are readily transferred into PBS buffer by replacing oleylamine with dopamine-based molecule. The strepavidin-biotin interaction is used to link nuclear localization signal (NLS) or antibody to iron oxide nanoparticles surface. Then platinum based anticancer drug is connected to Au in the Fe3O4-Au particles through coordination bonds. Fluorescent characterization and TEM shows that the functionalized nanoparticles are present in cell nucleus after incubated for 2-3 hours. The work demonstrates that the Fe3O4-Au dumbbell nanoparticles may be a powerful vector for targeted delivery of platin-like therapeutic agents.
9:00 PM - E3.28
Structural Stability of Copper-doped SnO2 Films Deposited by Spray Pyrolysis.
Ghenadii Korotcenkov 1 , Vladimir Brinzari 1 , Johannes Schwank 2
1 Lab. of Micro- and Optoelectronics, Technical University of Moldova, Chisinau Moldova (the Republic of), 2 Dep. of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States
Show Abstract9:00 PM - E3.29
Effects of Post Calcination Treatment on Photoluminescence and Structural Pproperties of Scheelite-type LiEuW2O8 Nanocrystals Synthesized by Glycothermal Reaction.
Ryo Kasuya 1 , Tetsuhiko Isobe 1 , Shinobu Yamao 2 , Hocine Sfihi 3
1 Department of Applied Chemistry, Faculty of Science and Technology, Keio Univ., Yokohama, Kanagawa, Japan, 2 , Idemitsu Kosan Co. Ltd., Kamiizumi, Chiba, Japan, 3 Laboratoire de Physique Quantique, ESPCI, Paris France
Show Abstract The scheelite-type LiEuW2O8 (LEW) nanocrystals were synthesized from metal acetates and dodecatungstophosphoric acid in 1,4-butylene glycol by the glycothermal reaction in autoclave. The transmission electron microscopy revealed the coalescence of the primary particles of ca. 50 nm in diameter. The convergent beam electron diffractometry with electron beam of 20nm in size exhibited a spot pattern of the tetragonal LEW single crystal, indicating that one particle consisted of a single crystallite. The powder x-ray diffraction pattern of the as-prepared sample well agreed with that of the bulk LEW, although two small diffraction peaks corresponding to (11(-1)) and (110, 001) of monoclinic β-KNdW2O8 appeared in one day after preparation. Post calcination treatment at 600oC for 2h increased the intensity of red emission by the excitation of 4f - 4f transition of Eu3+ by a factor of 24.4, and by the excitation of charge transfer (CT) from either O2- or WO42- to Eu3+ by a factor of 5.8. The inductively coupled plasma atomic emission spectroscopy revealed that the Li/Eu atomic ratio decreased from 0.80 to 0.75 after calcination. The thermogravimetry for the as-prepared sample showed a weight loss of 2.4 wt% below 300oC due to the desorption of solvents and the decomposition of the organic components, and the weight gain of 0.7 wt% from 300oC to 600oC, possibly assigned to the sorption of oxygen atoms. The latter might imply a non-stoichiometric structure of as-prepared LEW nanocrystals. The local structure of the samples was investigated by FT-IR, Raman and 7Li solid state NMR spectroscopies. The FT-IR and Raman results seemed to indicate a structural relaxation of WO4 units after calcination. The 7Li solid-state NMR spectra clearly showed the existence of two lithium sites in both as-prepared and calcined samples, which could be correlated to the presence of two phases. In contrast to FT-IR and Raman results, no significant change by calcination was observed by 7Li solid-state NMR. The obtained results suggest that three items can be improved by the calcination treatment to increase the f-f transition probability of Eu3+ : (i) a wide distribution of the Eu3+ - Eu3+ distance; (ii) a larger distortion of Eu3+ polyhedra and (iii) a lower symmetry of neighbored tetrahedral WO4 units. Furthermore, oxygen was provided for non-stoichiometric LEW during calcination to enhance the CT probability.
9:00 PM - E3.3
Correlation Between Size of the Nanoparticles and Chain Length of the Capping Alkanethiols in Controlled Thermal Evolution.
Mark Schadt 1 , William Cheung 1 , Chuan-Jian Zhong 1
1 Chemistry, State Univ. of New York at Binghamton, Binghamton, New York, United States
Show Abstract9:00 PM - E3.30
Characterization of Nanostructured Maghemite Thin Films Produced by Sol-Gel Processing.
Aylin Karakuscu 1 , Macit Ozenbas 1
1 Metallurgical and Materials Engineering, Middle East Technical University, Ankara Turkey
Show Abstract9:00 PM - E3.31
Synthesis and Surface Modification of FeM2O4 (M = Fe,Mn,Co) Nanoparticles for Potential Applications in DNA Sequence Detection.
Jin Xie 1 , Chenjie Xu 1 , Shouheng Sun 1 , Nader Pourmand 2 , Shanxiang Wang 3
1 Chemistry, Brown University, Providence, Rhode Island, United States, 2 , Stanford Genome Technology Center, Palo Alto, California, United States, 3 Department of Materials science and Engineering and Department of Electrical Engineering, Stanford University, Stanford, California, United States
Show Abstract9:00 PM - E3.32
Relation Between Silver Nano-particles and SERS Intensity.
Koichi Awazu 1 , Yasuhiko Iwanabe 2 1 , Makoto FUjimaki 1 , Junji Tominaga 1 , Toshiyuki Horiuchi 2
1 CAN-FOR, AIST, Tsukuba, Ibaraki, Japan, 2 Tokyo Denki University, Graduated School of Engineering, Tokyo Japan
Show AbstractThe goal of the present work is to obtain the shortest measurement time and the highest intensity of Surface enhanced Raman spectroscopy (SERS). Silver oxide films with various thickness from 5nm to 200nm was fabricated with the reactive ion sputtering method. He-Ne laser was employed as both light sources of irradiation and SERS observation. SERS was carried out for benzoic acid of 5micro molar dissolved in isopropyl alcohol. SERS intensity was increased with increase of laser irradiation time. Also SERS intensity against film thickness of silver oxide was examined. The highest SERS intensity was obtained at a 100nm thick silver oxide film. Direct observation of nano-particles with SEM indicated that SERS intensity was determined by size of nano-particles.
9:00 PM - E3.33
Novel Applications of Magnetic Nano Adsorbent for Rapid Analysis of Trace Metals in Biological Samples.
Pei-Ling Lee 1 , Chung-Yang Lee 2 , Yong-Chen Ling 3 , Yuh-Chang Sun 1 , Mo-Hsiung Yang 1
1 Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu Taiwan, 2 Materials Science and Engineering, National Tsing Hua University, Hsinchu Taiwan, 3 Chemistry, National Tsing Hua University, Hsinchu Taiwan
Show Abstract9:00 PM - E3.34
Room Temperature Synthesis of HgTe Nanocrystals
Linsong Li 1 , Daoyuan Wang 1 , Manav Mehta 1 , John Dixon 1 , Y Wang 1
1 , Ocean NanoTech, LLC, Fayetteville,, Arkansas, United States
Show AbstractMost recently, nanocrystals emitting in the far-red and near-infrared regions have generated many interests in various applications including in vivo biological imaging, the optoelectronics industry, and therapeutics. The reason is that in vivo biological imaging, infrared probes can well separate from autofluorescence background so that they eliminate interference from biological bodies and increase penetration of excitation and emission light through tissue comparing with visible probes (such as CdSe QDs). Currently, the synthetic technique has not fully developed for production of near-infrared QDs as imaging agents. In general, to synthesize high quality nanocrystals in organic solvents, high temperature (>200 C) is needed. Unfortunately, it is very difficult to incorporate mercury into these nanocrystals in organic solvents at such high temperature. In addition, the mercury precursors suitable for organic solvents are not only highly toxic (dimethylmercury) but also difficult to control at high temperatures (>100 C). Thereafter, it is important to find an approach to conduct the reaction of mercury chalcogenides at low temperature. In this paper, we report a new simple and robust approach to synthesize near-infrared emitting HgTe nanocrystals at room temperature. We report a new method to synthesize monodisperse zinc blende HgTe nanocrystals at room temperature in noncoordinating solvent-octadecene. Thiols were needed to control the reaction at a suitable nucleation and growth speed. In the early stage of the reaction, HgTe nanocrystals formed aggregates, and then the aggregates were dispersed and individual dot-shaped nanocrystals could be formed with stronger photolumenescence emitting. UV-vis, photoluminescence, and TEM have been used to study the properties of as-prepared HgTe nanocrystals.
9:00 PM - E3.35
Size, Shape and Composition Controllable Synthesis of Ce Based Oxide Nanoparticles by Hydrothermal Method Using Metal Oleic Complex
Takaaki Taniguchi 1 , Tomoaki Watanabe 1 , Anwar Ahiniyaz 2 , Nobuhiro Matsushita 1 , Masahiro Yoshimura 1
1 , Tokyo institute of technology, Yokohama Japan, 2 , Stockholm University, Stockholm Sweden
Show Abstract The synthetic technique of nanoparticles plays key role for advanced application of nanometric scale materials in future. Highly dispersed nanoparticles with uniform size, shape and composition are significantly important to fabricate the nanostructures such as nanocrystalline film, nano-porous material and self-assembled super-lattice. Stabilization of particles by surfactants is most efficient way to obtain monodispersed nanoparticles. Several methods have been developed to synthesize surfactant-coated nanoparticles including CeO2. However, these conventional methods normally use toxic, expensive and moisture sensitive materials as starting materials. These problems constitute barriers to mass-production for industrialization. On the contrary, hydrothermal synthesis is one of the best methods to synthesize crystallized nanoparticles in simple, low cost and environmentally friend way. Previously, our group successfully synthesized solid solutions nanoparticles such as ZrO2-CeO2, ZrO2-Y2O3 and HfO2-Eu2O3 with homogeneous shape, crystal size and composition by hydrothermal-coprecipitation method, but the obtained particles were rather agglomerate and insoluble in most solvents. For decades, many researchers focused on optimization of experimental conditions such as reaction temperature, duration, precursor, concentrations and pH to obtain less agglomerate nanoparticles. However it is still difficult to obtain monodispersed nanoparticles with few nm in size. In the present study, we used metal-oleate complex as chemically modified precursor. Recently, non-aqueous synthesizes of metal oxide nanoparticles using metal oleate compounds or complex as precursor have been reported. Here, we used metal oleate complex under hydrothermal condition at about 473 K. By optimizing the pH, we could successfully obtain monodispersed pure CeO2 nanocubes and Gd3+ or Zr4+ doped CeO2 nanospheres with about 5nm in size. They were re-dispersed easily in nonpolar organic solvent such as toluene and benzene because of their oleic acid stabilized surface. Based on the characterization by XRD, HRTEM and Raman scattering, the growth mechanisms and local structure of nanocrystals correlated with morphology, composition and reaction conditions have been discussed.
9:00 PM - E3.36
Phospholipid-Assisted Synthesis of Size-Controlled Gold Nanoparticles.
Peng He 1
1 Chemistry, North Carolina State University, Raleigh, North Carolina, United States
Show Abstract9:00 PM - E3.37
New Approach to Modeling Multilayer Irreversible Adsorption of Charged Nanospheres.
Pawel Weronski 1 2 , Marta Kolasinska 1 , Jakub Barbasz 1 , Zbigniew Adamczyk 1
1 Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow Poland, 2 Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Show AbstractMonte Carlo random sequential adsorption (RSA) modeling is a simple and effective method for computer simulation of localized, irreversible adsorption phenomena. Although the classical model deals with the simplest problem of hard, monodisperse spheres at a homogeneous interface, the approach can be extended to include a number of effects, e.g., particle anisotropy or polydispersity, Brownian motion, external force, electrostatic interaction or surface heterogeneity. In this presentation we discuss the extension of the approach allowing simulation of multilayer adsorption of electrostatically charged, monodisperse spheres. We use the model to describe the process of multilayer thin film formation as it occurs in experimental systems applying the method “layer by layer”. The method allows prediction of the multilayer structure in terms of 2D and 3D pair-correlation function, as well as the multilayer density distribution. We present the results of simulations of a multilayer composed of twenty monolayers, obtained for several different values of the first layer surface coverage at different values of ionic strength of the electrolyte. The theoretical results are in a good agreement with the results obtained in experiments.The research was supported by Polish Ministry of Scientific Research and Information Technology, research grant #3-T09A-089-27.
9:00 PM - E3.38
EXAFS Studies of TiO2 Nanoparticles.
Nathan Hould 2 , Juan Zhou 2 , Nadine Pernodet 2 , Miriam Rafailovich 2 , Anatoly Frenkel 1
2 Materials Science , Stony Brook University, Stony Brook, New York, United States, 1 Physics, Yeshiva University, New York, New York, United States
Show AbstractThe unique photocatalytic and semiconducting properties of titanium dioxide (TiO 2) based materials have been extensively studied in order to develop efficient photovoltaics, and novel air and water purification techniques. In the present study the effects of coating on the photocatalytic activity of TiO 2 nanoparticles was elucidated with measurements performed at beam line X18B of the National Synchrotron Light Source (NSLS). Particles were incubated in dermal fiberglass and the x-ray absorption fine structure (EXAFS) was measured in vitro. The particle size, dispersion, and morphology were determined using transmission and scanning electron microscopy. These data show that the activity of the nanoparticles as photocatalysts is dependent upon the external structure. Models to explain the data will be presented.
9:00 PM - E3.39
CO Adsorption and Oxidation on Silica-Supported Metal and Alloy Nanoparticle Catalysts.
Derrick Mott 1 , Andrew Smith 1 , Jeffrey Galkowski 1 , Jin Luo 1 , Chuan-Jian Zhong 1
1 Chemistry, State Univ. of New York at Binghamton, Binghamton, New York, United States
Show Abstract9:00 PM - E3.4
Sensitive Impurity Detection and Recognition in Inert Gaseous Media with SnO2 Based Gas Sensor Microarray.
Joachim Goschnick 1 , Thomas Schneider 1
1 Institut für Mikrostrukturtechnik, Forschungszentrum Karlsruhe, Karlsruhe Germany
Show Abstract9:00 PM - E3.40
The Role of Hydrogen Adsorption on Platinum Nanoparticles in the Formation of Gold Nanoparticles.
Peter Njoki 1 , Jin Luo 1 , Bilal Khan 1 , Suprav Mishra 1 , Ravishanker Sujakumar 1 , Chuan-Jian Zhong 1
1 Chemistry, State Univ. of New York at Binghamton, Binghamton, New York, United States
Show Abstract9:00 PM - E3.5
Monodisperse Gold Nanoparticles for Chemical and Biological Applications
Andrew Cooper 1 , Raphael Levy 1 2 , Irshad Hussain 1 4 , Zhenxin Wang 1 3 , Bien Tan 1 , Laurence Duchesne 2 , Mathias Brust 1 , David Fernig 2
1 Chemistry, University of Liverpool, Liverpool United Kingdom, 2 School of Biological Sciences, University of Liverpool, Liverpool United Kingdom, 4 , National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad Pakistan, 3 State Key Laboratory of Electroanalysis, Changchun Institute of Applied Chemistry, Changchun China
Show Abstract9:00 PM - E3.6
Selectivity and Specificity of Nanoparticle-Surface Interactions: Topology vs. Chemistry
Jason Benkoski 1 , Brian Berry 1 , Ronald Jones 1 , Alamgir Karim 1
1 Polymers Division, NIST, Gaithersburg, Maryland, United States
Show Abstract9:00 PM - E3.7
Functional Nanomaterials: From Extended to Nanoscale Surfaces
Vojislav Stamenkovic 1 , Nenad Markovic 1
1 MSD, Argonne National Laboratory, Argonne, Illinois, United States
Show Abstract9:00 PM - E3.9
Novel Synthesis of Polymer-Metal Nanocomposites.
Jose Morones 1 , Wolfgang Frey 2
1 Chemical Engineering, University of Texas at Austin, Austin, Texas, United States, 2 Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States
Show AbstractNanoparticles of noble metals have interesting optical, electrical, thermodynamic and chemical properties, many of which have a strong dependence on the particle size and shape, and the electronic configuration of the metal. Great interest has arisen to incorporate these particles into “intelligent materials”, materials that can react to an external stimulus and perform a desired mechanical or physicochemical action. The metal nanoparticles may act as amplifiers or modulators of the external stimulus, which makes these nanocomposits interesting for use in biomedical applications such as drug delivery vehicles and tissue engineering. Size and shape, and therefore many of the metal nanoparticle properties, are controlled typically by nucleation and capping agents, such as polyvinylpyrrolidone (PVP). Several steps of agent replacement and conjugation chemistry are needed in order to covalently attach environmentally responsive polymers to the metal nanoparticles to form “intelligent” composites. Here we demonstrate a system that is a composite of silver nanoparticles with an environmentally-sensitive polymer, p(N-isopropylacrylamide) (PNIPAM), where the polymer acts as the nucleating agent, the capping agent, and the environmentally sensitive actuator. We have developed a novel synthesis method that uses PNIPAM as nucleation and capping agent in the synthesis of silver nanoparticles to create a light and temperature responsive polymer-metal nanocomposite. The ability to cap the metal nanoparticles depends on the concentration of the polymer and cannot be achieved with the monomer NIPAM, although even the monomer can act as a nucleation agent. TEM studies show that we can control the growth process to form highly monodisperse colloidal suspensions with spherical shape particles. The product obtained not only has a narrow distribution of particle sizes, it additionally is a composite, which is temperature-sensitive without further conjugation at the for PNIPAM typical LCST of 32 °C. All of these processes are reversible, and the system can be cycled several times.
Symposium Organizers
Anis Zribi GE Global Research Center
Changming Li Nanyang Technical University
Larry Nagahara Motorola Labs
Magnus Willander Goeteborg University
E4: Nanotubes for Biological and Chemical Detection
Session Chairs
Larry Nagahara
Nongjian Tao
Tuesday AM, November 28, 2006
Room 210 (Hynes)
9:00 AM - **E4.1
Carbon Nanotubes for Field Effect Transistors
Mary Chan-Park 1
1 Chemical and Biomedical Engineering, Nanyang Technological University, Singapore Singapore
Show AbstractCarbon nanotubes (CNTs) are promising candidates for components of nanoscale electronic and electromechanical devices. However, several issues plague their industrial applications and these include dispersion and positioning. Controlled functionalization of the ends and/or sidewalls of the nanotubes are desirable to improve their dispersion and processibility. Many methods for nanotube functionalization have been reported but most of them relied on wet chemistry or exposure to high-temperature vapor. Toxicity and damage to nanotubes at high-temperature vapor are issues which must be addressed. Also, the successful exfoliation of undamaged long CNTs remains elusive. By comparison, plasma modification of nanotubes is an efficient and low-temperature method. We present the results of plasma modification of CNTs.
9:30 AM - E4.2
CNT Microsensor Modified with WO3 for NO2 Detection.
Takeshi Hashishin 1 , Jun Tamaki 1
1 Applied chemistry, Ritsumeikan University, Kusatsu, Shiga, Japan
Show AbstractCarbon nanotubes (CNTs) based gas sensors have received considerable attention because of their outstanding properties such as faster response, higher sensitivity, lower operating temperature. It is well known that WO3 is an excellent sensing material for NOx detection and can detect dilute NO2 less than 1 ppm with high sensitivity. In this study, we tried to modify the surface of CNT with WO3.At first, the micro-gap electrodes with various gap sizes were fabricated by means of MEMS techniques (photolithography and lift off). The Au line with width of 10-50 µm, gap size of 2-10 µm and thickness of 0.3 µm was deposited on SiO2 substrate by photolithography. Next, growth catalyst for CNTs, Ni, was deposited between Au electrode, in which 0.05wt% Ni(CH3COO)2 aqueous solution was dropped by using micromanipulator, dried for 30 min. The Ni-supported substrate was subsequently set on the electric furnace, and CNTs were grown from the Ni via ethanol CVD.The WO3 powder was prepared from ammonium tungstate (para) by wet process. Aqueous solution of ammonium tungstate (para) was neutralized by dilute nitric acid solution. The precipitate obtained (H2WO4) was thoroughly washed with deionized water, dried, and dispersed into ethylene glycol to be a suspension. The micro-drop of suspension was directly dropped on CNTs between Au electrodes with micro-gap (2-10 µm) by using micromanipulator, dried, and calcined at 400 degree C for 3 h under inert gas to prevent oxidation of CNTs. The surface morphology of the WO3 trapped on CNTs microsensor was measured by means of SEM (Hitachi, S-4800). The crystal structure of CNTs was evaluated by TEM and Raman spectroscopy.The CNTs microsensor modified with WO3 was set into a flow apparatus equipped with electric furnace and the sensing properties to dilute NO2 (0.05-5 ppm) were measured at R.T. to 250 degree C. The gas sensitivity (S=Ra/Rg) was defined as a ratio of resistance in NO2-containing atmosphere (Rg) to that in air (Ra).The entangled CNTs with 20-50 nm in diameter were grown at 700 degree C for 60 min under EtOH-Ar-H2 atmosphere (6kPa). The CNTs had multi-walled carbon layers and their Raman spectra indicated that G/D ratio was mostly closed to 1. The entangled CNTs formed the network structure by contacting each other, in which WO3 grains were independently trapped. The CNTs film formed between Au electrodes and was also deposited on an area other than micro-gap. Formation density of CNTs was high at the position that Ni(CH3COO)2 was dried after dropped. The grain size of WO3 trapped on CNTs was ranging from 50 to 200 nm and the grains were disk-like or platelet. The sensitivity of CNT microsensor with WO3 grains depicts about 2 at R.T. to 5 ppm NO2, which was higher than that of normal CNT microsensor, about 1, and the response time up to steady state in NO2 adsorption was less than 1 min. WO3 is considered to play a role of NO2 receptor which transmit NO2 adsorption as an electrical signal to CNT.
9:45 AM - E4.3
New Concept of Carbon Nanotubes tTransistor Natrix Based Sensor using Metal Diversification for Highly Selective Gas Imprinting.
Paolo Bondavalli 1 , Pierre Legagneux 1 , Vincent Dupuis 1 , Evelyn Chastaing 3 , Didier Pribat 2
1 NANOCARB, Thales Research and Technology, Palaiseau France, 3 DOO, Thales Research and Technology, Palaiseau France, 2 LPICM, Ecole Polytechnique, Palaiseau France
Show Abstract10:00 AM - **E4.4
Redox Based Strategy for the Detection of DNA using SWCNT Electronic Devices.
Salah Boussaad 1 , Bruce Diner 1
1 MSE, E.I. Dupont de Nemours, Wilmington, Delaware, United States
Show AbstractThere has been an increasing interest in the development of rapid, sensitive and selective detection methods of biological molecules. Here we report on a method for the detection of DNA where the hybridization of DNA is coupled to the presence of an enzyme onto the surface of a single-walled carbon nanotubes (SWCNT) device. This strategy was developed following our findings that SWCNT electronic devices are sensitive to the redox potential of the medium surrounding the carbon nanotubes (CNT). Our strategy is based on attaching 2 DNA probes, complementary to the target DNA, to the surface of the CNT device and the enzyme laccase. The presence of the target DNA would then form a sandwich and anchor the redox enzyme laccase to the surface of the CNT device. The enzyme is revealed by the addition of its substrate. The oxidation of the substrate by the redox enzyme causes an increase in the redox potential of the solution, which increases the source to drain current. We have detected with this technology 10atomoles of target DNA and distinguished between a perfect match sequence and one with a 3base deletion
10:30 AM - E4.5
Enhanced Sensitivity for Biosensors: Unique Roles of DNA Functionalized SWNTs in Self-Doped Polyaniline Nanocomposites
Yufeng Ma 1 , Shah Ali 1 , Huixin He 1
1 Chemistry, Rutgers University, Newark, New Jersey, United States
Show AbstractInspired by the remarkable electrical conductivity, the superior mechanical properties of carbon nanotubes(CNTs), and the rich optical, electrical and electrochemical properties of conducting polymers, nanocomposites of conducting polymers and CNTs have been pursued with a hope to synergistically combine their individual components. Here we report that a self-doped polyaniline/CNT nanocomposite was produced by in-situ polymerization of 3-aminophenylboronic acid monomers in the presence of single stranded DNA functionalized single walled carbon nanotubes (ss-DNA/SWNTs). Due to their unique surface and electronic properties, the ss-DNA/SWNTs performed multiple roles in the greatly improved performance of the self-doped polyaniline both during and after the polymerization, which makes this work unique compared to the previously reported conducting polymer/carbon nanotube composites. By electrochemically polymerization of the 3-aminophenylboronic acid monomers on gold substrate surface in the presence of the ss-DNA/SWNTs, we found that polymerization speed was greatly increased. More importantly, the stability of a self-doped polyaniline is greatly improved; the redox properties of the polyaniline backbone are preserved in neutral solutions (pH = 7.4), which opened the door for polyaniline in biosensor applications. We tested this idea by detecting an important neurotransmittor dopamine in neutral pH solutions. The detection limit reaches 10-12 M, 7 magnitude lower than that of electrodes modified with poly(aniline boronic acid) itself. We believe that the ss-DNA/SWNTs performed multiple roles in the greatly improved performance of the self-doped polyaniline both during and after the polymerization. First, they acted as effective catalysts and molecular templates during polymerization of self-doped polyanlines so that not only the polymerization speed was increased, but also the quality of the polymer was greatly improved. Second, they functioned as novel active stabilizers after the polymerization. They readily reduced the unstable fully oxidized pernigraniline form to the stable emeradine state of polyaniline due to the catalytic reductive ability of the ss-DNA/SWNTs. Furthermore, the ss-DNA/SWNTs also acted as conductive polyanionic doping agents in the resulting polyaniline film that shown enhanced conductivity and redox activity. Finally, the huge surface area of carbon nanotubes greatly increased the density of the functional groups for sensitive detection of the target analytes. We envision that polyaniline with other functional groups, as well as other conducting polymers can be produced for many different targeted applications using this approach.
10:45 AM - E4.6
Nano-Communications: Nanotube Communications.
Stephen Bush 1 , Yun Li 2
1 CDS, GE Global Research, Niskayuna, New York, United States, 2 MNST, GE Global Research, Niskayuna, New York, United States
Show AbstractTransferTuesday 11/28Q15.61 (poster) to E4.6 (oral)9:45 amNano-Communications: Nanotube Communications. Stephen F. Bush
11:30 AM - E4.7
DNA Nucleoside Interaction and Identification with Carbon Nanotubes.
Sheng Meng 1 , Paul Maragakis 2 , Costas Papaloukas 3 , Efthimios Kaxiras 1
1 Physics Department, Harvard University, Cambridge, Massachusetts, United States, 2 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States, 3 Department of Biological Applications and Technology, University of Ioannina, Ioannina Greece
Show Abstract11:45 AM - E4.8
Interactions of Carbon Nanomaterials With Mammalian Cells.
Pavan Raja 1 , Jennifer Connolley 2 , Lijie Ci 3 , Pulickel Ajayan 3 , Omkaram Nalamasu 3 4 5 , Gopal Ganesan 5 , Deanna Thompson 2
1 Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 3 Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 4 Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, United States, 5 Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York, United States
Show AbstractCarbon nanotubes (CNTs), despite their diverse application potential, have been found to have adverse effects in vitro, and in vivo. Previous research has focused on the in vitro cytotoxic impact of aggregates of CNTs and associated nanoparticulate impurities. In this study we have examined the effect of finely dispersed, non-aggregated carbon nanomaterials on rat aortic smooth muscle cells (SMCs), through filtration of the aggregates from the CNT-treated cell culture media. In general, our research shows that the removal of singlewalled carbon nanotube (SWNT) aggregates from cell culture test media inhibited the growth in SMCs to a lower extent than corresponding unfiltered media at pre-filtered SWNT dosages below 0.1 mg/ml. We also found suspended nanoparticles (likely amorphous and graphitic carbon associated with the SWNTs) and a small quantity of SWNTs in the filtered media, which may have caused the observed cell growth inhibition by the filtered media. Activated carbon (0.1 mg/ml), a nanoporous and microparticulate carbon material commonly used in biomedical applications, was found to be less inhibitory to SMC growth than the SWNT aggregates and suspended matter, implying an inverse proportionality between carbon nanomaterial size regimes and cell growth inhibition. We applied a new cell-enumeration method, wherein the fluorescently labeled nuclei of mononucleate cells are counted by image analysis, to determine cell growth kinetics in this study. Our experimental approach can potentially be applied to complement or validate current cytotoxicity assays, and to mechanistically understand the in vitro biological impact of other nanomaterials.
12:00 PM - **E4.9
Biosensing using Carbon Nanotube Field-Effect Transistors.
Alexander Star 1
1 , University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Show AbstractIt has been recently shown [1] that nanowires can readily change their conductance upon binding of charged target biomolecules to their receptor linked to their surfaces. Nanowires have the potential for very high sensitivity detection since the depletion or accumulation of charge carriers, which are caused by binding of the charged biomolecules at the device surface. This surface binding can affect the entire cross-sectional conduction pathway of the nanowire. For some nanowires, such as hollow carbon nanotubes, every atom is on the surface and exposed to the environment; thus even small changes in the charge environment can cause drastic changes to their electrical properties.This presentation covers recent advances in biodetection using carbon nanotube field-effect transistors (FETs). In the presentation I will briefly summarize interactions of carbon nanotubes with biomolecules (e.g., polysaccharides, DNA and proteins) to set a stage for some recent examples of carbon nanotube FETs based label-free electronic detection of proteins, antibody-antigen interactions, DNA hybridization, and enzymatic reactions [3-9].In addition to basic understanding of the biological processes, this nanotube FET molecular probe approach brings a prospect of building label-free detection methods for widest possible range of biological analytes. Further development of carbon nanotube FETs will result in hand-held field-ready devices as opposed to laboratory methods, which are using labor-intense labeling and sophisticated optical equipment, and will facilitate the high-throughput screening of large populations in a cost-effective manner. [1]Y. Cui, Q. Wei, H. Park, C. M. Lieber, Science 2001, 293, 1289.[2]A. Star, J.-C. P. Gabriel, K. Bradley, G. Grüner, Nano Lett. 2003, 3, 459.[3]R. J. Chen, S. Bangsaruntip, K. A. Drouvalakis, N. Wong Shi Kam, M. Shim, Y. Li, W. Kim, P. J. Utz, H. Dai, Proc. Natl. Acad. Sci. U.S.A. 2003, 100, 4984.[4]K. Besteman, J.-O. Lee, F. G. M. Wiertz, H. A. Heering, C. Dekker, Nano Lett. 2003, 3, 727. [5]S. Boussaad, N. J. Tao, R. Zhang, T. Hopson, L. A. Nagahara, Chem. Commun. 2003, 1502.[6]K. Bradley, M. Briman, A. Star, G. Gruner, Nano Lett. 2004, 4, 253.[7]R. J. Chen, H. C. Choi, S. Bangsaruntip, E. Yenilmez, X. Tang, Q. Wang, Y.-L. Chang, H. Dai, J. Am. Chem. Soc. 2004, 126, 1563.[8]A. Star, E. Tu, J. Niemann, J. -C. P. Gabriel, C. S. Joiner, C. Valcke, Proc. Natl. Acad. Sci. USA 2006, 103, 921.
12:30 PM - E4.10
Label-Free High-Sensitive Protein Detection Chip using Direct-Grown Carbon Nanotube Electrode Array.
Yuzuru Takamura 1 3 , Kerman Kagan 1 , Eiichi Tamiya 1 , Jun Okuno 2 , Kenzo Maehashi 2 , Kazuhiko Matsumoto 2
1 School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, Japan, 3 PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan, 2 Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan
Show AbstractWe have fabricated label-free amperometric protein detection chip with microelectrode array modified by single-walled carbon nanotubes (SWNTs). The carbon nanotube was directly grown by thermal chemical vapor deposition on Pt surfaces of the electrode array patterned on Si wafer chip. Using this chip, the high sensitive detection of a cancer marker, prostate specific antigen (PSA), was carried out by differential pulse voltammetry (DPV) after the immobilization of monoclonal antibodies for total prostate-specific antigen (T-PSA-mAb). Microfluidic pump and valves to be integrated on the chip for multi sensing system are also developed.SWNTs have been known to have the high ability to promote electron-transfer reactions in electrochemical measurements, because SWNTs have a high aspect ratio that the total surface area for electrodes becomes significantly larger on the same site. In this study, the electrochemical characteristics of the devices were investigated using K3[Fe(CN)6] and electro-active amino acids; such as tyrosine, cysteine and tryptophan by using differential pulse voltammetry (DPV). Furthermore, the electrochemical label-free detection of a cancer marker, prostate specific antigen (PSA), was carried out by DPV after the immobilization of PSA antibodies onto the SWNT-arrayed electrodes. The electrochemical signals using SWNT-arrayed electrodes were several ten times higher than those using bare Pt-arrayed electrodes, and that the area dependence of the signals were also clearly observed. These results indicate that the devices with SWNT-arrayed electrodes provide a much higher sensitivity to detect biomolecules. Moreover, biosensors for the cancer marker were fabricated by the immobilization of PSA antibodies to the SWNT-arrayed electrodes. The current signals increased after the PSA introduction onto the electrodes, resulting from the formation of antigen-antibody complexes. The detection limit of our method for PSA was determined as 0.5 ng/mL. The performance of this chip seems promising for further clinical applications. To use this sensor for clinical application of specific protein detection, non-specific protein not to be captured antigen should be washed out before DPV measurement. Microfluidic system with valves and pumps is helpful for this purpose. We have developed pneumatic-driven micro pump and valve which is simply able to be integrated in Polydimethylsiloxane (PDMS) made microfluidic system. The operation of these will also be demonstrated.
12:45 PM - E4.11
Magnetic Alignment of TiO2 Nanotubes.
Steve Semancik 1 , Casey Mungle 1
1 , National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Show AbstractA novel method for magnetically aligning TiO2 nanotubes has been investigated with potential use in chemical sensing. Metal oxide nanotubes have shown potential as highly sensitive chemical detectors due to their inherent material properties and structural scale. TiO2 nanotubes have been produced via template assisted solgel methods and Ni nanowires are electrodeposited inside the nanotubes, before dissolution of the alumina template, to provide a ferromagnetic core. Related techniques have been reported in literature for fabrication of high-density data storage and similar devices. However, we demonstrate the use of the magnetic core as a sacrificial layer to assemble ordered arrays of nanotubes. After removal of the template and dispersion of the nanotubes in solution, externally applied magnetic fields are employed to manipulate the nanotube/nanowire structures. A magnetic field gradient directs the nanotubes towards a substrate surface while the direction of the magnetic field allows alignment of the nanotubes in parallel orientation. Once in the desired configuration the Ni nanowires are removed with a chemical etch. This technique of using magnetic nanowires as a sacrificial layer for patterning of nanotubes allows one to assemble ordered arrays of metal oxide nanotubes, produced in batch processes, thereby enabling investigations of how the scale and orientation of nanotube arrays affects their sensing characteristics.
E5: Nano-Mechanical/Electrical Transduction for Biological and Chemical Detection
Session Chairs
Oliver Hayden
Larry Nagahara
Tuesday PM, November 28, 2006
Room 210 (Hynes)
2:30 PM - **E5.1
Nanomechanics and Sensors
Thomas Thundat 1
1 LSD, ORNL, Oak Ridge, Tennessee, United States
Show AbstractMolecular adsorption on surfaces results in changes surface stress of the substrate, and if the substrate is a cantilever, adsorption results in cantilever bending. The reaction-induced deflection of a cantilever beam reflects the interplay between strain energy increase of the beam and the free energy reduction of a reaction, providing an ideal tool for investigating the connection between mechanics and chemistry of reactions. Since free energy reduction is common for all reactions, the cantilever array forms a universal platform for label-free detection of various reactions. The advent of inexpensive, mass-produced cantilever arrays offers an unprecedented opportunity for the development of miniature sensors for multiplexed detection chemical and biological analytes. Chemical selectivity is achieved by using receptor based surface modification. The bending response of a cantilever, however, is extremely sensitive to many external parameters. This interference on cantilever bending could be qualitatively eliminated by simultaneous measurement of the bending and frequency response. It was also observed that certain adsorption process could cause significant enhancement in cantilever bending response. While the science underlying chemical-to-mechanical free energy transduction is still being understood, the technological potential can be truly realized if multiple reactions can be detected simultaneously. This talk will focus on both the scientific understanding as well as the technological progress in the development of cantilever-based analysis of chemical and biomolecular reactions.
3:00 PM - E5.2
Selectivity and Mechanism of Detection Sensitivity of Nerve Gas Simulant Detection Using Array PMN-PT/Cu Piezoelectric Microcantilever Sensors
Qing Zhu 1 , Wan Shih 1 , Wei-Heng Shih 1
1 Materials Science & Engineering, Drexel University, Philadelphia, Pennsylvania, United States
Show AbstractWe have examined Nerve gas stimulant, Dimethyl methylphosphonate (DMMP) detection using array PMN-PT/Cu Piezoelectric Microcantilever Sensors (PEMS). A PMN-PT/Cu microcantilever sensor 400-1000 micron in length 700-1000 micron in width is made of a piezoelectric lead magnesium niobate-lead titanate, (Pb(Mg1/3Nb2/3)O3)0.63(PbTiO3)0.37, (PMN-PT) freestanding film 8 (22) micron in thickness electroplated with 3 (5) micron Cu as the nonpiezoelectric layer by wire-saw cutting. For DMMP detection, an array of PEMS, each coated with a different absorbent, e.g., monolayer of Cu^2+ ions, self-assembled monolayer (SAM) of 3-mercaptopropyltrimethoxysilane (MPS), and mesoporous alumina are used where the Cu^2+ exhibits catalytic adsorption DMMP while the MPS exhibits steady adsorption of DMMP versus the reactive adsorption DMMP by mesoporous alumina. The selectivity of the PEMS will be examined by comparing the unique detection pattern of DMMP by the array PEMS to those of other organic compounds e.g., alcohol, methanol, and acetone. Furthermore, we will show that the PEMS immobilized with a SAM exhibited a high mass detection sensitivity of df/dm = 10^13 Hz/g where dm and df are the mass change and the corresponding resonance frequency change from the detection and a PEMS immobilized with a SAM of MPS is 25 times more sensitive than that coated with microporous silica that has a surface area 1000 times larger than the MPS SAM. The enhanced detection sensitivity of the PEMS with a SAM of receptors is attributed to surface stress induced by the binding which is more than 100 times larger than that by mass loading alone. The stress enhancement effect is examined with PEMS of various lengths, widths, thicknesses to elucidate how the binding stress enhances the detection sensitivity of PEMS, especially, that of PEMS immobilized with SAM.
3:15 PM - E5.3
Investigation of Cantilever Resonance Applied to Potentiometric Sensing.
Goutam Koley 1 , Lakshminarayanan Lakshmanan 1
1 Electrical Engineering, University of South Carolina, Columbia, South Carolina, United States
Show Abstract3:30 PM - E5.4
Detection of Bacillus Anthracis Spores Using Magnetostrictive Microcantilever-based Biosensor
Liling Fu 1 , Suiqiong Li 1 , Kewei Zhang 1 , Zhongyang Cheng 1
1 Materials Research and Education Center, Auburn University, Auburn, Alabama, United States
Show AbstractRecently, the magnetostrictive microcantilever (MSMC) as a high performance biosensor was introduced. The MSMC is a wireless sensor and exhibits a high Q value. More importantly, the MSMC works well in liquid. In this paper, the detection of Bacillus anthracis spores using MSMCs with filamentous phage as bioprobe is reported, that demonstrates the high performance of MSMC-based biosensors. The phased-coated MSMC biosensors with different lengths were exposed to cultures containing target spores with different concentrations. The spores were detected in real-time manner by monitoring the shift in the resonance frequency of the MSMCs in the cultures.
3:45 PM - E5.5
Mosfet-Embedded Microcantilevers: A New Electronic Signal Transduction Paradigm For Biochem Molecular Sensors
Gajendra Shekhawat 1 , Soo-Hyun Tark 1 , Vinayak Dravid 1
1 Material Science and Engineering, Northwestern University, Evanston, Illinois, United States
Show AbstractRecent advances in nanotechnology promise considerable and realistic potential for the development of innovative and high performance sensing and diagnostic approaches in biomedical field. In particular, the microcantilever detection paradigm based on direct transduction of molecular binding induced surface stress into a nanomechanical motion of microcantilevers, has attracted considerable attention for label-free detection of biomolecules. As an alternative to the currently deployed optical, piezoresistive, and capacitance nanomechanical detection techniques, we introduce a new electronic transduction paradigm comprising two-dimensional microcantilever arrays with geometrically configured metal-oxide-semiconductor-field-effect-transistors (MOSFETs) embedded in the high stress region of the microcantilevers. We have shown that the deflection of the microcantilever induced by specific ligand-analyte binding events leads to a precise, measurable and reproducible change in the drain current of the MOSFET buried in the microcantilevers. High current sensitivity of MOSFET-embedded platform enables detecting nanoscale cantilever deflection from specific biomolecular binding events at very low concentration of analytes. MOSFET-embedded microcantilevers, which realize integration of bio-nanostructures with microelectronics, are able to detect diverse probe-target binding events, ranging from DNA hybridization to protein-protein binding, at high sensitivity and reproducibility. Microcantilever arrays integrated with application-specific on-chip microelectronics platform will allow massively parallel signal sensing and multiplexing by simple direct current measurement. We believe label and optics free electronic MOSFET-embedded microcantilever detection paradigm will overcome the limitations imposed by currently available signal transduction and detection mechanisms and offer an excellent platform for variety of different biomolecular sensing applications, ranging from clinical diagnostics and environmental monitoring to drug discovery.
4:30 PM - **E5.6
Chemical Sensor Applications using Functionalized Conducting Polymer Wires.
Francis Tsow 1 , Erica Forzani 1 , Nongjian Tao 1
1 Electrical Engineering, Arizona State, Tempe, Arizona, United States
Show AbstractWe present a chemical sensor consisting of an array of sensing elements. Each element is a thin polymeric wire (diameter of 100 nm - a few microns) stretched across the two prongs of a microfabricated quartz tuning fork. When the fork is set to oscillate, the polymer wire is stretched and compressed by the two prongs. The stretching and compressing forces in the wire change upon adsorption of vapor molecules onto/into the polymer wire, which is detected by the quartz tuning fork. Since the polymer wire is formed by pulling a viscous polymer solution, individual polymer chains in the wire are forced to align along the pulling direction which results in a built-in stress in the wire after drying out. The built-in stress is partially released when analyte molecules adsorb onto the wire and change the interactions between the polymer chains, which give rise to a large mechanical response. Quartz is a piezoelectric material, so one can easily drive many sensing elements in an array into oscillations and detect the oscillations simultaneously with a simple circuit. Sensor discrimination performance can be achieved by 1) tuning the selectivity of each wire in the array, 2) using pattern recognition of the entire array, and 3) preferential preconcentrating the target molecules during the sample collection stage. Unlike most mechanical sensors that detect mass or surface stress changes, our sensor measures force changes in thin polymer wires. This approach is particularly attractive for detecting low molecular weight molecules, such as improvised explosives, because analyte adsorbed anywhere along a wire can trigger a change in the force of the entire wire. We have achieved a force sensitivity of a few pN, much smaller than the nN force required to break a single covalent bond.
5:00 PM - E5.7
Resonant Sensors for Microfluidic Applications.
Florentina Will 1 , Katja Tonisch 1 , Volker Cimalla 1 , Klemens Brückner 1 , Ralf Stephan 1 , Matthias Hein 1 , Oliver Ambacher 1
1 Institute of Micro- and Nanotechnologies, TU Ilmenau, Ilmenau Germany
Show Abstract5:15 PM - E5.8
Gallium Nitride BioFETs for Label-free Biomolecular Detection.
Kendra McCoy 1 , Keith Perkins 3 , Stephen Pearton 2 , Lloyd Whitman 1
1 Chemistry Division, Naval Research Laboratory, Washington, District of Columbia, United States, 3 Electronics Division, Naval Research Laboratory, Washington, District of Columbia, United States, 2 Materials Science and Engineering, University of Florida, Gainesville, Florida, United States
Show AbstractBiologically modified field effect transistors (BioFETs) have the potential to directly detect biochemical interactions in aqueous solutions for a wide variety of sensing applications. In order for these devices to be useful, they must satisfy three major criteria. BioFETs must be stable in aqueous solutions across a range of pH and salt concentrations; the surfaces of these devices must be functionalized for biomolecular recognition; and the devices must be sensitive to the changes in surface potential associated with specific recognition. We are developing and testing BioFETs based on AlGaN/GaN quantum well devices that we believe can satisfy all of these requirements. These charge-sensitive devices are being functionalized with receptors to sense the binding of target molecules in aqueous samples. The sensing is based on device geometries whereby the binding of a very low density of molecules (eventually single molecules) above a device will cause a detectable change in conductance. It has already been demonstrated that our AlGaN/GaN quantum well devices can sense small changes in pH of electrolyte solutions. We have also developed a robust, silane-free method of functionalizing the surface with Neutravidin. We can easily sense the binding of biotin to the surface on large area (1 cm x 1 cm) devices, demonstrating that the devices survive the functionalization chemistry and can operate in normal buffer solutions. We will report the changes in gate capacitance and channel conductance of these bioFETs for various types of molecular recognition reactions. Our progress in modeling the system and determining its ultimate sensitivity will also be discussed.
5:30 PM - E5.9
Post-processing of Commercial CMOS Chips for the Fabrication of DNA Bio-FET Sensor Arrays
Weihong Jiang 1 , Dolf Landheer 1 , Gregory Lopinski 2 , Alasdair Rankin 3 1 , Garry Tarr 3
1 Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, 2 Staecie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, 3 Department of Electronics, Carleton University, Ottawa, Ontario, Canada
Show AbstractA sensitive electrical method for the detection of DNA fragments and oligonucleotides could open the path to micro-array technologies, not dependent on bulky optical scanners that are not easy to apply in point-of-use applications. A sensor array built on a CMOS chip could also incorporate all the advantages of the latest advances in silicon technology; low cost, integrated analogue and digital signal processing, and optical or RF transfer of pre-processed data to a simple hand-held instrument. In the past decade, it has been shown that sensitive detection of DNA fragments should be possible using the field-effect on Si, raising the possibility of incorporating the sensors on chips using standard commercial Si MOS processes. We will show that a BioFET array can be fabricated by post-processing of a standard CMOS chip. Success depends on keeping post-processing and annealing temperatures below 450 °C, and minimizing radiation damage and contamination. The processing starts with encapsulation be deposition of a low stress, electrolyte-impermeable silicon nitride layer by PECVD at 375 °C. A He plasma with added ammonia, nitrogen and silane and a dual frequency process were evaluated. Working electrodes were created using a lift-off process with Au or Pt. Anisotropic reactive ion etching by an inductively coupled plasma with C4F8 and Ar was used to remove the silicon nitride and oxide layers above the poly-silicon gates. The poly-silicon was then etched off using a highly selective wet etch and any trapped charges or interface states could be annealed out at low temperatures. The effect of the processing was characterized by making current-voltage and capacitance-voltage measurements with MOS capacitor structures at each stage of processing. Scanning electron microscopy was used to examine the cross-section of the gate area structures before and after the etching. The final result was an oxide/Si gate structure with trapped charges and interface state densities not significantly larger than the as-received chips. The results of current-voltage characteristics of devices in electrolyte solutions were compared to the results of charge-sheet model calculations including the effect of amphoteric charging sites on the oxide and the potential drops in the electrolyte. The potential drop across the working electrodes was monitored with a Ag/AgCl reference electrode. Further measurements were performed after aminosilane functionalization of the SiO2 layer, to deduce the level of passivation of the amphoteric sites. Measurements showing the threshold shifts subsequently produced by DNA probe attachment and hybridization will also be presented.
5:45 PM - E5.10
Nanoelectronic Biomolecular Field-Effect Transistor (BioFET) Sensor
Yu Chen 1 , Xihua Wang 1 , Agnes Kalinowski 2 , Shyamsunder Erramilli 1 , Pritiraj Mohanty 1
1 physics department, Boston University, Boston, Massachusetts, United States, 2 school of medicine, Carnegie Mellon University&University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Show AbstractWe report preliminary results of biomolecular recognition by the measurement of conductance change of bio-functionalized nanowires. The change is primarily due to the contribution of surface states to the conductance, which for larger sensors is dominated by volume effects. The fractional change is greatest for the smallest sensors, due to the increased surface-to-volume ratio. Our silicon nanowires are fabricated from SOI (silicon on insulator) wafer by electron beam lithography, which provides highly controllable nanowire sensors in comparison to other nanoelectronic approaches. The design of multiwires in parallel makes it possible to keep the big surface volume ratio while increasing signal to noise ratio. Differential conductance change due to the pH value of the solution is detected for the silicon nanowire functionalized by APTES. This FET sensor can also be used to selectively detect biomolecules such as protein concentration in solution. We acknowledge support by the Department of Defense MSRP program (W81XWH-04-1-0578) and the National Science Foundation (DBI-0242697).
E6: Poster Session: Nanomaterials/Nanotransduction for Biological and Chemical Detection
Session Chairs
Changming Li
Larry Nagahara
Magnus Willander
Anis Zribi
Wednesday AM, November 29, 2006
Exhibition Hall D (Hynes)
9:00 PM - E6.1
Application of Nanosize Amorphous Oxides of MoO*2 as Humidity-sensing Materials.
Armen Markosyan 1 2 , Razmik Malkhasyan 2 , Sergo Kamanchadgyan 2 , Eduard Pashinyan 2
1 theoretical physics, Yerevan State University, Yerevan Armenia, 2 , "Nanoamorph Technology" JSC, Yerevan Armenia
Show Abstract9:00 PM - E6.10
Large Area Molecular Devices for Electronics and Sensing
Ajit Mahapatro 1 , Jiewen Ying 2 , Tong Ren 2 , David Janes 1
1 School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, United States, 2 Department of Chemistry, Purdue University, West Lafayette, Indiana, United States
Show AbstractMolecular electronic devices, e.g. devices in which molecules are coupled to electrical contacts, could provide a platform for chemical sensing. In such a device, selective binding events could be converted directly into electrical signals. Realization of molecular electronics at a conventional photolithographic scale is still challenging with current technologies. For metal-molecule-metal (M-M-M) vertical device structures, the bottom contact roughness is an important issue, since it impacts the quality of the organic monolayer and may alter the degree of metal penetration through the molecular layer. This work demonstrates a technique to fabricate controlled molecular electronic devices over a large area (~ 100 x 100 µm2), suitable for integration in conventional electronic circuitry. The bottom contact of the device is an ultra-flat Au surface, prepared using a lithographically-compatible technique1. Micron-scale atomic force microscopy indicates sub-nanometer surface roughness. A monolayer of a dithiol functionalized molecule is formed by solution-based self-assembly on the Au surface. The top electrodes are formed by stamping Au from polydimethylsiloxane (PDMS) pads of various dimensions, avoiding evaporation and potential metal. The M-M-M junctions show conductance vales that scale with the junction area. The electrical properties of molecular monolayers of various molecules (alkane dithols [HS-(CH2)n-SH], oligo(phenylene ethylene) [OPE], and oligo(phenylene vinylene) [OPV]) are measured and compared with reported results. Electrical conductivities through alkane-dithiol junctions scale exponentially with the chain length. Though the same dependence is observed in junctions with single/few alkane chain molecules that are wired between nanoscale contact gaps2, the estimated values for single molecule conductivity is less in large area junctions. The measured conductances for OPE-based M-M-M devices are approximately 4 x 10-11 S per molecule, assuming a surface coverage of 4.6 molecules/nm2. OPV devices exhibit 10-15% higher conductances than the OPE devices. Both the OPE and OPV molecules shows reproducible and reversible bistable switching when operated at biases above 1.5V. The devices show a two fold increase in conductance upon switching, and return to their original conductance levels when an opposite polarity bias of the same magnitude is applied. The current demonstration makes it possible to realize molecular electronic devices (as conducting wires, switches, rectifiers, and memory elements) in a conventional scale that can be used in the next generation technologies for molecular electronics and biosensor applications.References:(1) A. K. Mahapatro, A. Scott, A. Manning, and D. B. Janes, Appl. Phys. Lett. 88, 151917, 2006.(2) A. K. Mahapatro, S. Ghosh, and D. B. Janes, IEEE Trans. Nano Tech. 5, 232, 2006.
9:00 PM - E6.12
Development of a High Frequency Love Mode Surface Acoustic Wave ZnO/SiO2/Si Biosensors.
Soumya Krishnamoorthy 1 , Thaleia Bei 3 , Emmanouil Zoumakis 3 , George Chrousos 3 , Agis Iliadis 1 2
1 Department of Electrical and Computer Engineering, University of Maryland, College Park, College Park, Maryland, United States, 3 , National Institute of Health, Bethesda, Maryland, United States, 2 Department of Information and Communication Systems Engineering, University of the Aegean, Mytilene Greece
Show Abstract9:00 PM - E6.13
Synthesis and Electronic Properties of Peptide Coated Gold Nanoparticle Networks
Joseph Slocik 1 , David Phillips 1 , Jeffrey Zabinski 1 , Rajesh Naik 1
1 Materials and Manufacturing Directorate, Wright Patterson AFB, Wright-Patterson AFB, Ohio, United States
Show AbstractPeptide coated gold nanoparticles are appealing because of their narrow size distributions, various morphologies, optical and electronic properties, and biologically active peptide coatings. To date, the main impetus has been on synthesis and recognition capabilities with a variety of different sequences; although recently, there has been some interest in exploiting their electronic properties for sensing applications. Such applications include sensing viruses, environmental threats, gases, and chemical agents, simply by designing the peptide sequence to elicit a specific response. Herein we have prepared gold particles with a multifunctional peptide that displays excellent electronic properties when assembled into a device. Additionally, the conductivity of peptide coated gold networks changes rapidly and substantially in response to certain vapors/chemical agents. In comparison to other gold nanoparticle films, peptide coated gold nanoparticles exhibit a response to vapors that is several orders of magnitude greater than uncoated nanoparticles.
9:00 PM - E6.14
Development of Nanoscale Cell Injectors Based on Carbon Nanotubes.
Xing Chen 1 , Andras Kis 2 , Alex Zettl 2 , Carolyn Bertozzi 1
1 Department of Chemistry, University of California, Berkeley, Berkeley, California, United States, 2 Department of Physics, University of California, Berkeley, Berkeley, California, United States
Show Abstract9:00 PM - E6.15
PLD Growth of CNTs using a Nanostuctured Ni Buffer Layer: Dependence of H2 Oartial Pressure.
Maneesh Chandran 1 , Mohan Kant 1 , Saurabh Madaan 1 , Mahidanna Rao 1
1 Physics, Indian Institute of Technology, Chennai, TamilNadu, India
Show Abstract9:00 PM - E6.16
Ultra - Pure, Catalyst Free MWCNTs for Chemical and Biological Detectors in the Vapor Phase
Bill Riehl 1 , Mike Check 1 , Elmo Blubaugh 1 , Bill Mitchel 2 , John Boeckl 2
1 , Riehl-Check Industries, Kettering, Ohio, United States, 2 Electromagnetic Materials, Air Force Research Laboritories, Wrigh Patterson Air Force Base, Ohio, United States
Show Abstract9:00 PM - E6.17
Multiwalled Carbon Nanotube Based Hydrocarbon Differentiator
Shalini Prasad 1 , SudhaPrasannakumar Padigi 1 , Ravikiran Reddy 1
1 , Portland State University, Portland, Oregon, United States
Show Abstract9:00 PM - E6.18
Effect of Carbon Nanotube Chirality on the Adhesion to DNA
Marwan Al-Haik 1 , Yousef Haik 2
1 Mechanical Engineering, University of New Mexico, Albuquerque, New Mexico, United States, 2 Department of Mechanical Engineering, United Arab Emirates University, Al Ain United Arab Emirates
Show Abstract9:00 PM - E6.19
Scanning Probe Microscopy Investigation of Aldehyde–terminated Self-assembled Monolayers.
Alexandru Riposan 1 , Yih Horng Tan 1 , Christopher Fleming 1 , Gang-yu Liu 1
1 Chemistry, University of California, Davis, California, United States
Show AbstractThe structure of aldehyde-functionalized self-assembled monolayers (SAMs)/Au(111) is revealed for the first time by high-resolution scanning tunneling microscopy (UHV-STM), and by atomic force microscopy (AFM). SAMs of 11-mercapto-1-undecanal (HS(CH2)10CHO) were prepared by solution immersion. In comparison with alkanethiol SAMs, the introduction of aldehyde-termini results in lower degree of long-range order and higher density of point defects, from both STM and AFM observations. As-deposited SAMs consist of small domains (2 – 10 nm) displaying the basic (root3xroot3)R30° periodicity, in addition to numerous disordered regions. The domain size is further reduced for aldehyde structures created by AFM-based nanografting, due to the different growth kinetics within the spatially constrained nanopaterns. Upon UHV annealing at 325 – 365 K, the size of the ordered domains increase in conjunction with the appearance of various c(4x2) superstructures. The understanding of the structure of aldehyde SAMs is important for their application in protein immobilization and biochemical reactions.
9:00 PM - E6.2
Development of Nano-sized Semiconductor Metal Oxide and Its Three Models for Selective Detection of NH3
Chuncai Yang 1 , Brent Marquis 1
1 , Sensor Research & Development Corporation, Orono, Maine, United States
Show Abstract9:00 PM - E6.20
Platinum in Nanoporous Carbon: A Shape Selective Catalyst for Deep Desulfurization of Diesel Fuel
BillyPaul Holbrook 1 , Ramakrishnan Rajagopalan 2 , Ponnaiyan Ayyappan 3 , Henry Foley 2
1 Chemistry, Pennsylvania State University, State College, Pennsylvania, United States, 2 Chemical Engineering, Pennsylvania State University, State College, Pennsylvania, United States, 3 Chemistry, University of Iowa, Iowa City, Iowa, United States
Show AbstractNanoporous carbon, NPC, with tunable porosity allows for shape-selective adsorption of specific aromatic compounds. NPC are good candidates for super capacitors, gas storage materials, membranes and super absorbants. In this work, we report synthesis of shape selective platinum/carbon catalyst, which is highly active to perform deep desulfurization of diesel fuels. Platinum nanoparticles are formed by reduction of platinum acetylacetonate under UV light in the presence of furfuryl alcohol. The platinum nanoparticle containing alcohol is then polymerized via acid-catalyst polymerization. The polymerized furfuryl alcohol platinum nanoparticle solution then undergoes heat treatment under an inert gas to yield platinum nanoparticle embedded inside nanoporous carbon. In this investigation, it was demonstrated that the platinum NPC acts as an active catalyst for deep desulfurization of 4,6-DMDBT, dimethyldibenzothiophene, a common contaminate in model fuels. The platinum NPC was characterized using X-Ray Diffraction, Hydrogen Chemisorption, BET Surface Area, Transmission Electron Microscopy, and X-Ray Photoelectron Spectroscopy.
9:00 PM - E6.21
Fabrications of Nano-gap Arrays using Doubly Clamped Free-standing Si Nanowire.
Han Young Yu 1 , Chil Seong Ah 1 , Ansoon Kim 1 , In Bok Baek 1 , Chang Geun Ahn 1 , Jong Heon Yang 1 , Seong Jae Lee 1
1 Nano-bio electronic device team, ETRI, Daejeon Korea (the Republic of)
Show Abstract9:00 PM - E6.22
Fabrication of Silver Nanowires Using Domain-patterned Ferroelectric Templates.
Jacqueline Hanson 1 , N. Malchus 1 , B. Rodriguez 1 , A. Gruverman 1 , R. Nemanich 1
1 Physics and Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina, United States
Show Abstract Metal nanowires capable of establishing electrical connections at the molecular level are the key elements of nanoelectronic devices including field-effect transistors, sensors and light-emitting diodes. In this study, we present a liquid phase processing method that allows fabrication of silver nanowire structures by selective deposition on ferroelectric domain boundaries in domain-patterned lithium niobate templates. Selective deposition on ferroelectric surfaces is typically domain-specific being governed by Coulomb interaction between polarization charges and charged species. Additionally, when a ferroelectric material is illuminated by super band-gap light, electron-hole pairs are generated which become available for electrochemical reactions on the surface of a domain with certain polarization. In previous studies, ferroelectric barium titanate (BTO) and lead zirconate titanate (PZT) have been used as templates for domain specific depositions, where metal deposition occurred on the surface of positive domains due to reduction of metal ions from the aqueous solution. In our work, it is shown that for domain patterned lithium niobate silver deposition occurs preferentially along the domain boundaries resulting in nanowire structures. We have fabricated nanoscale domain patterns in lithium niobate via conducting tip AFM. The nanowire size and location can be controlled by generating these domain patterns of desired configuration and varying deposition conditions, such as temperature, solution concentration, and UV light exposure time. We consider the difference in the surface termination and electronic properties of the materials to explain this effect; the selective deposition process is described by a combination of the inhomogeneous distribution of the electric field in the vicinity of the domain wall and the polarization screening mechanisms of the template material. This research is supported by NSF (Grant No. 0403871, NIRT on Nanopatterned Polar Surfaces).
9:00 PM - E6.23
Novel Gas Sensors Based on Hybrid Nanostructures
Ganhua Lu 1 , Liying Zhu 1 , Stephen Hebert 1 , Leonidas Ocola 2 , Junhong Chen 1
1 Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States, 2 Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois, United States
Show AbstractMiniaturized gas sensors that rapidly detect trace amount of chemical agents are extremely attractive for many applications, such as environmental monitoring, medical diagnosis, food processing, and custom security checking for contraband agricultural products. Use of tin oxide nanoparticles instead of conventional films as sensing elements can significantly improve the response time and the sensitivity of current gas sensors. Gas sensors based on carbon nanotubes (CNTs) have also demonstrated remarkable sensitivity. Here we report on a miniaturized gas sensor fabricated with hybrid nanoparticle-nanotube structures. The sensor is fabricated by combining “top-down” e-beam lithography and “bottom-up” directed assembly. First, nonagglomerated pure/doped tin oxide nanocrystals are produced from an atmospheric mini-arc plasma source. Most of the product nanocrystals are electrically charged exiting the mini-arc reactor and the size of the nanocrystals can be varied from a few to tens of nanometers. A small number of tin oxide nanoparticles/quantum dots will then be electrostatically assembled onto CNTs dispersed on an e-beam lithographically patterned interdigitated electrode. The tin oxide nanoparticles deposited on the CNT sidewall may be considered as artificial dopants due to the ballistic electrical conductance of CNTs at room temperature. Both electrons and holes will be strongly scattered by electrostatic potential of the nanoparticle dopant, which can be externally modulated through the interaction with analyte molecules. The synergistic response from CNTs and tin oxide nanoparticles is expected to significantly improve the performance of gas sensors. The sensing performance of the novel nanohybrid gas sensor will be evaluated against hydrogen and ethanol. The effects of nanocrystal size, doping, and packing density on the gas sensing performance will be investigated. The unique capability of controlling nanocryctal size and doping nanocrystals with the mini-arc plasma source will allow us to address the selectivity of gas sensors.
9:00 PM - E6.24
Sensing Arrays Constructed from Nanoparticle Thin Film Assemblies and Interdigitated Microelectrodes
Lingyan Wang 1 , Xiajing Shi 2 , Bridgid Wanjala 1 , Karan Sarup 1 , Guannan Wang 1 , Jin Luo 1 , Susan Lu 2 , Chuan-Jian Zhong 1
1 Chemistry, State Univ. of New York at Binghamton, Binghamton, New York, United States, 2 Department of systems science and industrial engineering, SUNY at Binghamton, Binghamton, New York, United States
Show AbstractThe interparticle spatial or chemical properties of molecularly-capped nanoparticles have been explored for chemical sensing in a number of significant ways in terms of high sensitivity. A challenging area is the enhancement of selectivity in complex sensing environment. This paper describes the results of a study of sensing arrays constructed from nanoparticle thin films and interdigitated microelectrodes to tackle the challenge. The effects of interparticle distance, nanoparticles film thickness, and some design parameters of interdigitated microelectrodes (IMEs) on the performance of sensor arrays are investigated. The sensor responses of the nanostructured thin films to volatile organic compounds on IME arrays derived from Au nanoparticles linked by dithiols or acid-functionalized thiols, and AuAg alloy nanoparticles linked by dicarboxylic acids are determined. The array data were analyzed using fractional factorial experimental design and analysis of variance for understanding effects of the microelectrode design parameters on the sensitivity and selectivity. While the smaller values for the microelectrode space, width, and length generally led to higher response sensitivity, a strong dependence on the nature of the nanostructured thin films was discovered. The principal component analysis results from classification performances of the sensor arrays consisting of a set of thin films with controlled design parameters have further demonstrated the possibility of optimizing sensor arrays by appropriate selections of the microelectrode parameters and the nanostructured sensing films.
9:00 PM - E6.25
A Polydiacetylene-Based Label-Free DNA Chip
Doo Ho Yang 1 , Eun Jin Kim 1 , Gil Sun Lee 1 , Dong June Ahn 1 , Jong-Man Kim 2
1 Chemical & Biological Engineering, Korea University, Seoul Korea (the Republic of), 2 Chemical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractPolydiacetylene-based supramolecules are interesting materials in view of application to chemical and biological sensors. Since the first report of the colorimetric detection of the influenza virus by using a polydiacetylene (PDA) film (Science 1993, 261, 585), the development of efficient sensory systems based on PDAs has continued to be of great interest. It is difficult to detect simultaneous screening of various binding events with solution-phase vesicles or solid-phase film.Recently, we were successful in immobilization of the polydiacetylene vesicles on glass substrates without losing their unique color changing property (Adv. Mater. 2003, 15, 1118). Also we reported on printing of ink-jet spotter to make microscale dot patterns. Each dot is found to possess the color-changing property as well as the fluorescence emission. This technique allows us, for the first time, to fabricate sensory chips based on polydiacetylene vesicles (JACS 2005, 127, 17580).In this study, we have developed an approach for the construction of PDA-based label-free DNA chip systems which is compatible with conventional microarray technologies. By using lethal factor DNA sequence of E. coli and Anthrax virus, self-emitted fluorescent patterns were generated. Then, it was proved that such fluorescent change is induced by specific DNA hybridization between probe DNA of patterned PDA vesicles and target DNA. Combining this methodology with modern array-based sensing technologies, the stress-induced self-fluorescent nature of the PDAs should be widely applicable to the development of new and interesting PDA-based protein and cell chip systems.
9:00 PM - E6.26
Detection of Cells using Polydiacetylene Supramolecules Functionalized with Aptamers
Gil Sun Lee 1 , Hyun Choi 1 , Kyung Woo Kim 1 , Jung Wun Son 1 , Min Kyu Oh 1 , Dong June Ahn 1 , Jong-Man Kim 2
1 Chemical & Biological Engineering, Korea University, Seoul Korea (the Republic of), 2 Chemical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractPolydiacetylene (PDA) supramolecules are unique in terms of their output fluorescent emission signals, when PDA vesicles are turned to red from blue state in response to environmental perturbations such as heating, pH or ligand-acceptor interactions. After Charych et. al. first used PDAs to detect influenza virus, there have been intensive research efforts to develop PDA-based chemosensor systems. However, most efforts have focused on developing solution-based sensor systems, which are less sensitive against smaller amount of analytes than PDA vesicle sensors immobilized on solid state substrates. Aptamers selected from a large random sequence pool to bind to specific target molecule have been of great interest to be used for both basic research and clinical purposes as macromolecular drugs.In this study, anti-E.coli RNA aptamer is incorporated into a PDA supramolecule system to confirm whether this system can be used as a biosensor. Avidin-biotin reaction is adopted for immobilization of vesicle and attachment of aptamer to vesicles. After E.coli cells react with aptamer-functionalized PDA vesicles, the vesicles emit red fluorescence by itself, even without any labeling treatment. At the same time, Bacillus subtillus cell reaction with aptamer-attached vesicles and E.coli reaction with vesicles without aptamer do not show any fluorescent signals. In addition, the intensity of red fluorescence is dependent on reaction time and concentration of E.coli. These results indicate that PDA vesicles functionalized with aptamer can be applied to a label-free cell chip for detection of various pathogens.
9:00 PM - E6.27
Spherical Carbon Nanostructures - A Versatile Material for Sensing and Energy Storage.
Bettina Friedel 1 , Siegmund Greulich-Weber 1
1 Department of Physics, University of Paderborn, Paderborn Germany
Show AbstractMonodisperse smooth carbon nanospheres were synthesized via preparation and complex subsequent multistage pyrolysis of spherical melamine formaldehyde copolymer microparticles. The diameters of obtained carbon spheres were located between several tens to several hundreds nanometers depending on the size of used initial copolymer particles. During the conversion of copolymer to carbon, the spheres pass strong shrinking of more than 80% without any deformation. They meet the high quality standards of common prepared and used polymer or silica spheres and are therefore a promising material with great potential. Subsequent modification of carbon spheres could be achieved by wet-chemical oxidation followed by e.g. coating with silica. Carbon nanoparticles could be used in a wide range of applications, such as for gas storage, fuel cells, sensing, catalyst support, separation and purification, supercapacitors or lithium-ion batteries, and photonic bandgap materials. Especially for the last mentioned usage monodispersity and a perfect spherical shape are very important. So-called synthetic opals from carbon spheres have been grown via sonic-supported sedimentation and a photonic bandgap in the infrared region has been found. Due to their high thermal resistance under non-oxidizing conditions carbon opals are also suitable as template for inverse opals. The structure of spheres has been studied during different stages of carbonization by scanning electron microscopy, nuclear magnetic resonance and fourier transform infrared spectroscopy. The properties of the carbon opals were determined using scanning electron microscopy, fourier transform infrared spectroscopy and current-voltage measurements.
9:00 PM - E6.28
Enhanced Stem Cell Adhesion and Spreading on Carbon Nanotubes Grown on Anodized Titanium.
Batur Ercan 1 , Thomas Webster 1
1 Engineering, Brown University, Providence, Rhode Island, United States
Show Abstract9:00 PM - E6.29
Cyclodextrin Sensor Using Polydiacetylene Supramolecule Integrated on ZnO, SiC and Glass Substrates
Chung Wan Lee 1 , Hyun Choi 1 , Jihyun Kim 1 , Dong June Ahn 1 , Gil Sun Lee 1 , Jong-Man Kim 2
1 Chemical & Biological Engineering, Korea University, Seoul Korea (the Republic of), 2 Chemical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractPolydiacetylene (PDA)-based liposomes are interesting materials in view of application to chemical and biological sensors because of unique characteristic in changing color from initial blue to red upon specific binding events, caused by shortening of delocalization length of π-electrons along diacetylenic backbones. It is known that they are self-emitting red fluorescence in red phase, but no fluorescence in blue phase. It has been reported that various binding events including viruses, toxins, glucose, ionic interactions, and inclusion complex are detectable using such characteristics. Recently we were successful in immobilization of the PDA liposomes on glass substrates without losing their unique color changing property. In this study, we have investigated patterning of PDA liposomes integrated on ZnO, SiC and glass substrates via micro-arrayer. The shape and size of patterned PDA liposomes on all the substrates were uniform and reproducible. The size of them was about 200μm in diameter. The patterned substrates were reacted with cyclodextrins (CDs) because these CDs have different binding specificities against α, β, and γ-CDs. And these CDs form host-guest inclusion complex with specific supramolecules, which make it valuable to study the ligand-receptor interactions. Self-emitting red fluorescence was induced in only the reaction between PDA liposomes and α-CD, however there was no fluorescence change in case of β, γ-CDs. These results conform that only α-CD is able to form inclusion complex with PDA liposomes.This result is an important first step in the application of the PDA liposome system extended to ZnO or SiC based chemical sensors and to the integration with ZnO or SiC based microelectronics. This detection method could be applied as DNA chip, protein chip, and cell chip for multiple screening as well as chemical sensors by modifying the functional groups of diacetylene monomer.
9:00 PM - E6.3
Cytocompatibility of Nanotubes Patterned on FDA Approved Polymers for Orthopedic and Neural Applications.
Dongwoo Khang 1 , Thomas Webster 1 , Jong Youl Kim 2 , Jong Eun Lee 2
1 Division of Engineering, Brown University, Providence, Rhode Island, United States, 2 Anatomy, College of Medicine, Yonsei University, Seoul Korea (the Republic of)
Show AbstractRecently aligned nano materials have been studied for a variety of uses in biomedical applications. However, conventional fabrication methods to align nanomaterials and their cytocompatibility assessment have been inadequate. This is because such aligned patterns of nanomaterials have been formulated on conventional solid materials, not FDA approved materials, using methods developed to align micron or nano-sized materials. Alignment of nanomaterials need to be completed on FDA approved materials and using new alignment methods geared especially for nanomaterials. For this reason, the present study formulated various aligned patterns of biocompatible nano materials (such as nano hydroxyapatite and carbon nanotubes) on bio-degradable and bio-nondegradable FDA polymers (specifically, poly-lactic-co-glycolic acid or PLGA and poly-carbonate-urethane or PCU) for neural and orthopedic applications. Specifically, cell functions critical for orthopedic and neural applications have been measured on patterns of nano hydroxyapatite and carbon nanotubes created on polymers using a specially designed grid alignment method. Preliminary results indicated the enhanced adsorption of adhesion proteins and subsequently aligned patterns of osteoblasts (bone forming cells), neurons, and stem cells on the various nano-structured aligned materials. In this manner, the present study provides evidence of the ability to control cell functions by aligning nanomaterials on FDA-approved polymers for improving orthopedic and neural applications.
9:00 PM - E6.30
Use of High Surface Area TiO2 Nanosheet in Dye-sensitized Solar Cell
Sorapong Pavasupree 1 2 , Susumu Yoshikawa 1
1 , Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan, 2 Department of Materials and Metallurgical Engineering, Faculty of Engineering, Rajamangala University of Technology Thanyaburi , Klong 6, Thanyaburi , Pathumthani, Thailand
Show AbstractTitanium dioxide (TiO2) has been widely used for various applications such as a semiconductor in dye-sensitized solar cell, water treatment materials, catalysts, gas sensors, and so on. In the view point of surface area, nanosheet and nanotubes (from nanosheet rolling technique) TiO2 (or titanate) offered high surface area (about 100-400 m2/g). In our previous works, nanofibers TiO2 were synthesized by hydrothermal and post heat-treatments from natural rutile sand, however, nanofibers TiO2 had rather low surface area (10-20 m2/g). In this study, high surface area nanosheet TiO2 with mesoporous structure (with much higher surface area, 642 m2/g) has been synthesized, which shows high performance in dye-sensitized solar cell. The detail microstructure and photovoltaic properties will be reported. High surface area nanosheet TiO2 were synthesized by hydrothermal method at 130 oC for 12 h. The samples characterized by XRD, SEM, TEM, SAED, and BET surface area. SEM image of the as-synthesized sample, indicating the flower-like morphology composed of nanosheets. The flower-like structure had diameter about 500 nm to 2 mm. The nanosheet structure was slightly curved and approximately 50-100 nm in width and several nanometers in thickness. The electron diffraction pattern supported that the nanosheet was anatase-type TiO2, which corresponding to the XRD results (low crystallinity of anatase TiO2). The pore size distribution of the sample showed that the nanosheet TiO2 with narrow pore size distribution had average pore diameter about 3-4 nm. The BET surface area and pore volume of the as-synthesized nanosheet TiO2 were about 642 m2/g and 0.774 cm3/g, respectively. The solar energy conversion efficiency (h) of the dye-sensitized solar cell using the nanosheet TiO2 was about 7.08 % with Jsc of 16.35 mA/cm2, Voc of 0.703 V and ff of 0.627; while h of the cell using P-25 reached 5.82 % with Jsc of 12.74 mA/cm2, Voc of 0.704 V and ff of 0.649.
9:00 PM - E6.31
Microfabricated, Wireless, Magnetoelastic Biosensors for the Detection of Biological Warfare Agents.
Jiehui Wan 1 3 , Michael Johnson 1 3 , Huihua Shu 1 3 , Valery Petrenko 2 3 , Bryan Chin 1 3
1 Material Engineering, Auburn University, AUBURN, Alabama, United States, 3 , Auburn University Detection & Food Safety Center, Auburn University, Alabama, United States, 2 Department of Pathobiology, Auburn University, Auburn, Alabama, United States
Show Abstract9:00 PM - E6.32
Fabrication and Characterization of a Poly (3-Hexylthiophene) Thin Film Micro-sensor for Hypergolic Vapor Detection
Huihua Shu 1 , John Shu 1 , Jiehui Wan 1 , Hong Yang 1 , Bryan Chin 1
1 Materials Research and Education Center, Auburn University, Auburn, Alabama, United States
Show AbstractHydrazine compounds are a highly toxic and carcinogenic species exhibiting toxic effects in humans at very low levels of exposure. Therefore, a sensor capable of detecting ppb levels of hydrazine compound is required to insure the personnel safety. Here we report the fabrication, testing, and characterization of a low-cost, ultrasensitive Poly (3-Hexylthiophene) (P3HT) thin film-based micro-sensor for hydrazine compound detection. The standard microelectronic manufacturing techniques are used to form a micro-sensor composed of silicon substrate, interdigitated gold electrodes, and P3HT sensing film. Responses of the micro-sensor to hydrazine compound at different temperatures and concentration levels are reported. The results show that the compensation interactions between P-type doped P3HT and reducing hydrazine compound result in the orders of magnitude increase in the resistance of the sensor. Thermally-induced performance modifications and thermal stability of P3HT thin film micro-sensor are also explored. It is found that thermally annealing the P3HT micro-sensor improves the thermal stability of the device at high temperatures. In addition, the sensor exhibit good specificity to hydrazine in the presence of NO2 and N2O.
9:00 PM - E6.33
Rational Self-Assembly into Functionalized Lipid Nanotubes and Their Encapsulation Abilities of Biomacromolecules
Naohiro Kameta 1 , Mitsutoshi Masuda 1 2 , Toshimi Shimizu 1 2
1 , SORST, Japan Science and Technology Agency (JST), Tsukuba Japan, 2 , Nanoarchitectonics Research Center (NARC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Japan
Show AbstractSupramolecular nanotubes self-assembled from amphiphilic molecules have attracted much attention in the field of nanotechnology and biotechnology [1]. Hydrophilic hollow cylinder of the naotube functions as a suitable cavity for biomacromolecules, and plays important roles in acting as nano-containers and nano-channels [2]. In addition, distinct inner and outer surfaces of the nanotubes functionalized differently are also attractive to achieve selective and effective encapsulation of the biomacromolecules. Recently, we have established to selectively construct the nanotubes with different inner and outer surfaces via self-assembly of wedge-shaped bolaamphiphiles [3,4]. Herein, we describe the control of inner diameters of the lipid nanotubes with different inner and outer surfaces, and their encapsulation abilities for the biomacromolecules such as spherical proteins and DNA. Self-assembly of the bolaamphiphile, having a 1-glucosamide group at one end of an oligomethylene spacer and an aminoethylamide group at the other end, gave two types of nanotubes with different inner diameters (20 and 80 nm), in weak-acid and alkaline aqueous solutions, respectively. Molecular packing analysis indicated that both nanotubes are based on monolayer lipid membranes, in which the bolaamphiphile molecules packed in parallel fashion within each layer. Since those nanotubes have different inner and outer surfaces covered with amino and glucose groups, respectively, only the inner surface should be charged positively as a result of protonation of the amino groups under neutral pH conditions. Therefore, negatively charged biomacromolecules will be selectively and effectively encapsulated into the hollow cylinder of the nanotubes via electrostatic interaction. Transmission electron microscopic measurement showed that both nanotubes were able to encapsulate the spherical protein, ferritin, in neutral aqueous solutions without external force. Moreover, time-resolved fluorescence microscopic observation combined with fluorescence resonance energy transfer technique demonstrated the encapsulation of fluorinated DNA (5 micrometers length) in the hollow cylinder of the nanotube with 80 nm inner diameter.References[1] a)C. R. Safinya et al., Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 11167; b)E. Gazit et al., Nano. Lett.. 2005, 5, 183; b) X. Gao and H. Matsui, Adv. Mater. 2005, 17, 2037; c)A. J. Russell et al., J. Am. Chem. Soc. 2004, 126, 13400; d) G. John et al., J. Am. Chem. Soc. 2004, 126, 15012.[2] T. Shimizu et al., Chem. Rev. 2005, 105, 1401.[3] M. Masuda and T. Shimizu, Langmuir 2004, 20, 5969. [4] N. Kameta et al., Adv. Mater. 2005, 17, 2732.
9:00 PM - E6.35
Nanoporous Silicon Sensor for Biological Applications
Gagik Ayvazyan 1 , Vahe Buniatyan 1
1 Nano- and Microelectronics, State Engineering University of Armenia, Yerevan Armenia
Show Abstract9:00 PM - E6.36
The Use of Photochemical Organic Hydride Donors in Explosives Detection.
Trisha Andrew 1 , Timothy Swager 1
1 Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractThin films of 9,10-dihydroacridine and 9,10-dihydroanthracene derivatives embedded in a cellulose acetate matrix are exploited as small-molecule “turn-on” sensors for the detection of explosives, such as RDX and PETN. Poly(phenylene ethynylene)s with 9,10-dihydroacenes incorporated in the repeat unit effect signal amplification by taking advantage of an increase in conjugation length upon analyte binding. Thin films of both 9,10-dihydroacridine and 9,10-dihydroanthracene exhibit weak violet-blue fluorescence; however, upon prolonged irradiation (λ<450nm) in the presence of oxygen or RDX/PETN, the 9,10-dihydroarenes are oxidized to generate a high-quantum yield fluorophore with a new, red-shifted emission peak. 9,10-Dihydroarene PPEs, synthesized via standard cross-coupling methods, demonstrate a marked increase in emission intensity upon exposure to either RDX or PETN while exhibiting greater resistance to photooxidation under ambient conditions.
9:00 PM - E6.37
Nanoporous Gold Structures: Characterization and Control of Morphology
Totka Ouzounova 1 , Leila Joy Roberson 1 , Christopher Umbach 1
1 Materials Science and Engineering , Cornell University, Ithaca, New York, United States
Show AbstractNanoporous gold (NPG) produced from Au-Ag alloys has been used in various biological applications, such as estimating the degree of immobilization for alkanethiols and proteins [Bonroy K. et al., Anal Chem 2004; 76(15), 4299]. The high surface area of NPG due to the nanoscale porosity that occurs during dealloying under free corrosion and the ability of gold to be functionalized afterwards make NPG potentially useful for sensor applications, bioelectrodes, etc. NPG evolves during thermal treatments, making it possible to tune the ligament size within the porous network. The evolution of the pore morphology has been studied as a function of both the annealing conditions and the ambient atmosphere. We observed that the pore size depends superlinearly on the annealing time, coarsening from 30 nm to several microns. The temperature-dependent coarsening rate of the pore size also depends strongly on the oxygen concentration in the ambient. Here we present a study of characteristic morphological changes of 200 μm thick membranes when annealed over a range of temperatures (from 25 οC to 600 οC) in a variety of ambients (vacuum, oxygen, argon and a mixture of nitrogen and oxygen). The observed coarsening phenomena can be related to a model that includes curvature-driven diffusion, surface energetics and stress. Very similar coarsening is observed for sputter-deposited films of NPG that are ~400 nm in thickness. We discuss the influence on the pore morphology of these NPG thin films due to film properties such as grain size and intrinsic and extrinsic stress. Under certain deposition conditions it is possible to produce crack-free films on silicon substrates with variable pore sizes. The tunability of the pores is very attractive for lab-on-chip microfluidic applications, where a range of size-selecting filters could be manufactured within a single structure.
9:00 PM - E6.38
DAPI Method: A Novel Assay to Evaluate the In vitro Impact of Nanomaterials on Mammalian Cells
Pavan Raja 1 , Jennifer Connolley 2 , Pulickel Ajayan 3 , Omkaram Nalamasu 3 4 5 , Deanna Thompson 2
1 Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 3 Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States, 4 Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, United States, 5 Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York, United States
Show AbstractThe increasing importance of nanomaterial-related applications has given rise to concerns pertaining to their impact on human health. In vitro mammalian cell-based assays can provide a quick and simple estimate of the possible adverse effects of the nanomaterials. However, recent studies have questioned the efficacy of traditional assays such as the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, in evaluating cell-nanomaterial interactions, implying the need for alternate methods. Our approach, based on the application of image analysis to enumerate the DAPI (2-[4-(Aminomethyl)phenyl]-1H-indole-6-carboximidamide, dihydrochloride) -stained nuclei of mononucleate cells offers several advantages compared to the MTT assay, and other older methods such as hemocytometry, and can be used to complement or verify results from them. The results of a sample study to evaluate the impact of singlewalled carbon nanotubes (SWNTs) on rat aortic smooth muscle cell (SMC) growth kinetics, using this method is presented. We anticipate that the “DAPI method” can also be applied to evaluate the biological impact of other nanomaterials.
9:00 PM - E6.39
Improved Through Thickness Thermal Conductivity in Adhesive Joints.
Sabyasachi Ganguli 1 , Ajit Roy 2
1 NRC Research Associate, AFRL/WPAFB, Dayton, Ohio, United States, 2 , AFRL/WPAFB, Dayton, Ohio, United States
Show Abstract9:00 PM - E6.4
Detection of Protein in Serum Using a Piezoelectric Microcantilever Sensor
Joseph Capobianco 1 , Wan Shih 1 , Wei-Heng Shih 1
1 Materials Science & Engineering, Drexel University, Philadelphia, Pennsylvania, United States
Show AbstractIn this study, we investigate the in-situ quantification of breast cancer markers such as Human Epidermal Receptor, HER2, in simulated sera using piezoelectric microcantilever sensors (PEMS). The PEMS were either constructed using lead zirconate titanate (PZT) bonded with a thin glass layer or using the lead magnesium niobate-lead titanate (PMNPT) freestanding film electroplated with tin as the nonpiezoelectric layer. The PEMS offer all-electrical actuation and detection. Immobilized with a specific receptor, binding of an antigen causes the PEMS's resonant frequency to shift, which is monitored for detection. Several approaches have been investigated to immobilize single chain variable fragments (scFv) specific to HER2 and other cancer markers on the insulated surface for optimal detection of the antigens. The results indicated that the PEMS immobilized with scFv selectively detect cancer antigens in solution of bovine serum albumin (BSA) with no reduction in its sensitivity (10^-13 g/Hz). The effects of the ratio of HER2 to BSA will also be discussed.
9:00 PM - E6.5
Fabrication of Novel Types of Microcapsules with Gelled Cores: Colloidosomes and Liposomes and Carbon Nanotubosomes
Vesselin Paunov 1 , Paul Noble 1 , Olivier Cayre 2 , Rossitza Alargova 2 , Orlin Velev 2 , Marc Panhuis 1
1 Department of Chemistry, University of Hull, Hull, North Humberside, United Kingdom, 2 Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, United States
Show AbstractWe report a versatile fabrication method of novel microcapsules which is based on the following 3 stages: (i) Hot aqueous solution of gelling hydrocolloid is emulsified in a suitable oil in the presence of solid polymer particles dispersed in the aqueous phase to produce a water-in-oil emulsion stabilised by the solid particles and the system is cooled off to set the gel. (ii) The produced suspension of aqueous gel microcapsules coated with a particle monolayer is separated by filtration to remove the oil phase. (iii) The microcapsules are washed and collected into water. This methodology allows us to produce colloidosome microcapsules of diameters varying between several tens of micrometers to several hundreds of micrometers. The function of the gel cores was to support the particle shell around them and to give the microcapsules enough stiffness to be separated from the oil phase by filtration. Following this technique we have been able produce three different types of colloidosome microcapsules. (a) By combining monodisperse amino-latex microparticles and an oil which swells the latex we have fabricated integral colloidosomes of porous membrane where the pore size is controlled by the degree of swelling. (b) By using monodisperse amino-latex particles and cross-linking agent we were successful in producing colloidosomes of spherical particle monolayers, where the membrane pores are defined by the particle size. (c) By using polymer micro-rod particles as emulsifiers we have synthesized for the first time “hairy” colloidosomes which shells consists of randomly assembled rod-like particles.We also report a technique for fabrication of giant liposome microcapsules based on aqueous gel cores encapsulated with a lipid bilayer. The method involves templating of lipid-stabilised water-in-oil emulsions after gelling the aqueous phase with a suitable hydrocolloid. These novel microcapsules have much higher stability and mechanical strength than conventional liposomes and may find applications as drug delivery vehicles and for controlled release of proteins, vaccines, cosmetic and food supplements. This technique has also been extended to produce microcapsules of carbon nanotubes by an emulsion-inversion. Self-assembled carbon nanotubes at the interface of water and oil were covalently cross-linked to produce hollow micro-capsules consisting of carbon nanotube shells. It is expected that these carbon nanotumosome capsules could aid the development of encapsulation of catalysts.
9:00 PM - E6.6
The Step-stone Approach for the Electrodepositing of Metallic Nanotubes in Al2O3 Membranes.
Woo Lee 1 , Roland Scholz 1 , Kornelius Nielsch 1 , Ulrich Goesele 1
1 Experimental Dept. II, Max Planck Institute of Microstructure Physics, Halle Germany
Show Abstract9:00 PM - E6.7
A Nanoparticle-based Nano-gapped Film Electrode for Sensor Applications.
Tsutomu Nagaoka 1
1 , Osaka Pref. Univ., Sakai, Osaka, Japan
Show Abstract9:00 PM - E6.9
Polyaniline Based pH Monitor.
A. Bishop 1 , P. Gouma 1
1 Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York, United States
Show AbstractElectrospun polyaniline based hybrids have been produced to monitor varying levels of pH in exhaled breath. The level of pH found in the breath can be used to determine the amount of oxidative stress associated with the onset of illness. This paper details the response mechanism of electrospun leucoemeraldine based polyaniline composite mats to pH ranging from 4 -10. Results reveal a decrease in the mat’s resistance as a function of pH. Such sensors may act as indicators for early detection and monitoring of diseases such as asthma.
Symposium Organizers
Anis Zribi GE Global Research Center
Changming Li Nanyang Technical University
Larry Nagahara Motorola Labs
Magnus Willander Goeteborg University
E7: Nano-Optics/SPR Transduction for Biological and Chemical Detection
Session Chairs
Salah Boussaad
Magnus Willander
Wednesday AM, November 29, 2006
Room 210 (Hynes)
9:00 AM - E7.1
Label-free Protein Detection Using Silicon Based Photonic Crystal.
Mindy Lee 1 , Philippe Fauchet 2 1
1 , The Institute of Optics, Rochester, New York, United States, 2 , Department of Electrical & Computer Engineering , Rochester, New York, United States
Show AbstractTraditional fluorescence and radioactivity labeling methods introduce complexity in sample preparation and potential contaminations to the biological specimen. Label-free optical biosensors thus have recently attracted great attentions in the fields of pharmaceutics, antiterrorism and food safety. In our study, we focus on using two-dimensional photonic crystal (PC) as a platform and study the optical response corresponding to the probe and target protein binding recognition. PC microcavity can be obtained by introducing a point defect in the perfect PCs. The transmission spectrum can be characterized by resonance peaks whose positions are very sensitive to the binding of biological molecules onto the pore wall. In this presentation we discuss the details of device fabrication on silicon-on-insulator (SOI) wafer and internal surface functionalization for protein detection. A variety of protein binding recognitions are monitored by measuring the optical resonance shifts. The magnitude of the shift depends on the amount of material captured by the internal surface. This device has a small internal surface of < 100 um2, thus, it requires a very small amount of analyte (less then 5 pg/mm2). A plane-wave expansion method is used to model the resonance shift due to the binding process. The simulation results are in good agreement with the experimental data. Dehydrated Glutaraldehyde protein diameter is characterized using this technique and the sensitivity of this device is approximately 6% of a protein monolayer. The optimization of the device performance and potential applications are discussed further in detail.
9:15 AM - E7.2
New Template-Stripping Method to Create Ultraflat Composite Materials for Non-Spherical Metal Nanoparticle Surface Plasmon Sensors
Bongsu Jung 1 , Wolfgang Frey 1
1 Biomedical engineering, University of Texas at Austin, Austin, Texas, United States
Show AbstractLabel-free detection techniques have an important role in many applications, such as situations where few molecules – rather than low molarity – need to be detected, such as in single-cell screening. While surface plasmon resonance (SPR) scattering from metal nanoparticles has been shown to achieve significantly higher sensitivity in gene arrays, such an approach has not been demonstrated for protein arrays. SPR-based sensors could either use simple absorption measurement in a UV-Vis spectrometer or possibly surface-enhanced Raman spectroscopy as the detection mechanism for molecules of interest. However, non-spherical particles are needed to achieve high sensitivity and field enhancement that is a requirement in both techniques, but these shapes are not easy to produce reproducibly, and to preserve for extended periods of time. A technique to create and partially embed non-spherical metal nanoparticles into the surface of a glass substrate has been demonstrated by us earlier. The technique is in principle able to detect molecular binding events while preserving the particle shape through bioconjugation steps, but because the technique relies on template stripping, its use as a plasmon sensor has been hampered by the imperfection of the stripping process, leading to extinction peak broadening and variations in the peak position. Here we demonstrate a self-assembly fabrication technique that is able to produce template-stripped surfaces that are a composite of a non-spherical metal nano-particle (gold or silver) and an embedding material such as glass. The stripping process is defect-free due to the introduction of a sacrificial layer, but different bonding strength of the sacrificial layer to the two materials in the composite had to be overcome. The new nanocomposite surfaces now show well-defined SPR extinction peaks with locations in the visible or infrared spectrum depending on the metal and the particle size and the degree of non-symmetry. The peak position in the VIS-NIR spectrum is dependent on the environment of each particle, and each particle can act as its own sensor. Optimization of the non-spherical geometry of the metal nanoparticle leads to a strongly increased sensitivity to changes in the local refractive index, exceeding that of other LSPR configurations. The resulting arrays of silver or gold nanoparticles in the surface of a glass slide are capable of detecting thiol surface modification, protein binding, and their binding kinetics. Since each gold or silver particle can principally acts as an independent sensor, on the order of a few thousand molecules can be detected, and it can be miniaturized without loss of sensitivity. The atomically flat surface of our template stripping process is also precious for general absorption studies, because an inherent material contrast can resolve binding of layers on the 1-2 nm scale.
9:30 AM - E7.3
Plasmon Coupling in Reconfigurable Nanoparticle Assemblies.
Anne Lazarides 1
1 Dept of Mech Eng and Mat Sci, Duke University, Durham, North Carolina, United States
Show AbstractMetal nanoparticle assemblies support plasmon resonances that are highly sensitive to interparticle spacing, when particles are positioned within the near fields of their neighbors. Biomolecular linkers that control interparticle separation can, therefore, be used to control resonant frequencies and, thus, the frequencies of high near field enhancement. We have observed near field coupling in sub-wavelength sized, biomolecule-linked, core/satellite structures and similar effects in extended nanoparticle networks. In both sub-wavelength and extended assemblies, we have used reconfigurable tethers to control interparticle plasmon coupling. While the effects of coupling in noble metal nanoparticle assemblies comprised of particles of like composition are qualitatively similar, assemblies of unlike particles display a richer set of signatures. Accurate electrodynamic calculations confirm the observed relationships between assembly structure, composition, and optical properties. Approximate, analytic, dipole coupling models provide insight into the material-dependence of the observed band modulation phenomena.
9:45 AM - E7.4
Development and Optimization of Metal Nanoparticles for Surface-enhanced Raman Spectroscopy.
Alia Sabur 1 , Mickael Havel 1 , Guzeliya Korneva 1 , Davide Mattia 1 , Selcuk Guceri 1 , Yury Gogotsi 1
1 , Drexel University, Philadelphia, Pennsylvania, United States
Show AbstractRaman spectroscopy is a widely-used technique used to obtain structural information of materials and identify molecular species. However its major limitation is the low signal sensitivity. Surface-enhanced Raman spectroscopy (SERS) was developed to enhance the weak Raman signal and enable detailed analysis of chemical contents from complex specimens. It can be used for the detection of nano amounts of substances. This trace analytical capability is most interesting for biological studies, allowing molecular identification at the nanoscale. This is especially important because biologically relevant molecules are often available for characterization in extremely small amounts. While SERS can provide information unavailable with any other technique, it still has some difficulties. The colloidal nanoparticles used in SERS are generally gold or silver and are created by reduction of the metal salt using sodium citrate. These colloidal particles can be useful for SERS but only with a perfect control on all experimental parameters: size, shape and aggregation. Compared to spherical particles, faceted particles show an exceptionally large electric field, especially at their tips. This electric field can lead to "giant enhancement” factors (up to 10^14). This also reduces the need for aggregation, as spherical nanoparticles must be in aggregates to form the so-called "hot-spots". Although these advantages have been discussed theoretically in detail, only a small amount of studies have been done using faceted colloidal nanoparticles. This work focuses on the size and shape effect of colloidal nanoparticles on the resulting SERS signals. By adjusting the synthesis conditions and the properties of the resulting nanoparticles, the signal can be optimized. Glycine, a simple amino acid, was used as a SERS test analyte because of its simple structure, and the fact that it is a natural precursor to more complicated biological molecules. It is demonstrated that the SERS signal intensity can be increased by three orders of magnitude by using nanotriangles instead of spherical gold colloid. This enables observation of analyte at extremely low concentrations. In addition, these optimized SERS-active nanoparticles were used for the development of nanotube-based nanoprobes for the monitoring of molecular processes inside cells. This allows us to take advantage of the fact that the lateral resolution of SERS is not determined by the diffraction limit, but by the spatial confinement of the local fields (a few tens of nanometers).
10:00 AM - **E7.5
High Sensitive SERS Viral Detection with Silver Nanorod Array
Yiping Zhao 1 , Saratchandra Shanmukh 2 , Les Jones 3 , Richard Dluhy 2 , Ralph Tripp 3
1 Physics and Astronomy, University of Georgia, Athens, Georgia, United States, 2 Chemistry, University of Georgia, Athens, Georgia, United States, 3 Infectious Diseases, University of Georgia, Athens, Georgia, United States
Show AbstractThe aligned silver nanorod array substrates prepared by the oblique angle deposition method are capable of providing extremely high enhancement factors (~109) at near-infrared wavelengths (785 nm) for a standard reporter molecule 1,2 trans-(bis)pyridyl-ethene (BPE). The enhancement factor depends strongly on the length of the Ag nanorods, the substrate coating, the polarization of the excitation light, as well as the incident angle. A detailed optical characterization of the substrate is presented. With the current optimum structure, we demonstrate that the detection limit for BPE can be lower than 0.1 fM. We also show that SERS can be used to detect the molecular fingerprints of several important human respiratory viruses including respiratory syncytial virus, rhinovirus, adenovirus, and human immunodeficiency virus, and to discriminate between different virus strains. These results suggest that the emergence of bioanalytical methodologies that leverage nanotechnology for direct, rapid, and sensitive detection of viruses may bridge the gap between the limited sensitivity levels of current bioassays and the burgeoning need for more rapid and sensitive detection of infectious viral agents.
10:30 AM - E7.6
Optical Sensing of Local Biomechanical Fields using Gold Nanorods as Light-Scattering Imaging Agents
Sarah Baxter 1 , John Stone 2 , Patrick Sisco 2 , Edie Goldsmith 3 , Catherine Murphy 2
1 Mechanical Engineering, University of South Carolina, Columbia, South Carolina, United States, 2 Chemistry, University of South Carolina, Columbia, South Carolina, United States, 3 Cell and Developmental Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina, United States
Show AbstractIt has been well-established that cellular response to mechanical environment is critical to cell/tissue function. Numerous studies have examined the bulk mechanical response of biological tissue; many others have focused on the response of individual cells under mechanical load. In vivo, however, it is a dynamic local mechanical relationship between cells and their extracellular matrix (ECM) which may more clearly define the complex mechanisms associated with mechanical transduction. We have developed a novel measurement technique which utilizes gold nanorods to facilitate the tracking of local deformations between cells and the ECM. Gold nanorods are prepared via a wet chemical synthesis, whereas as-prepared gold seeds (~ 4 nm gold spheres) are added to a solution containing gold, cetyltrimethylammonium bromide (CTAB), and ascorbic acid. Because of their unique optical properties, when viewed under dark field microscopy, the nanorods elastically scatter light; color and intensity are functions of nanoparticle size, aspect ratio and local environment. In this work, gold nanorods with lengths ~ 500 nm and widths of 25-30 nm were embedded in cell-populated (neo-natal cardiac fibroblasts) collagen films. The natural rearrangement and remodeling of the ECM by the cells, endogenous loading via cell traction forces, or external loading creates a changing mechanical environment within the gel construct. The resulting pattern of the scattered light is then used in the context of image analysis, i.e. pattern matching, to measure local displacement and strain fields by comparing an undeformed reference state to images taken during deformation.
10:45 AM - E7.7
Imaging Shape Dependent Plasmons in Nobel Metal Nanoparticles.
Shaul Aloni 1
1 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States
Show Abstract11:30 AM - E7.8
Optical Fiber Biosensors Utilizing Turnaround Point Long Period Gratings with Self-Assembled Polymer Coatings.
Erika Gifford 1 , Zhiyong Wang 1 , Siddharth Ramachandran 2 , James Heflin 1
1 Dept. of Physics, Virginia Tech, Blacksburg, Virginia, United States, 2 , OFS Laboratories, Somerset, New Jersey, United States
Show AbstractIonic self-assembled multilayers (ISAMs) adsorbed on Long Period Fiber Gratings (LPGs) can serve as inexpensive, robust, portable, biosensor platforms. The ISAM technique is a layer-by-layer deposition approach that creates thin films on the nanoscale level. The bilayer thickness of ISAM films can be finely controlled from 0.3 to >10 nm through variation of the pH and ionic strength of the deposition solutions. The combination of ISAMs with LPGs yields exceptional sensitivity of the optical fiber transmission spectrum. We have shown theoretically that the resonant wavelength shift for a thin-film coated LPG can be caused by the variation of the film’s refractive index and/or the variation of the thickness of the film. The high refractive index nanoscale film dramatically shifts the propagation constant of the cladding mode while having negligible effect on that of the core mode, thus yielding the large shift in the wavelength of optimal coupling. We have experimentally demonstrated that the deposition of nm-thick ISAM films on LPGs induces shifts in the resonant wavelength of > 1.6 nm per nm of thin film. Using unique turnaround point (TAP) LPGs that manifest a broadband attenuation peak that shifts in transmitted intensity level rather than the wavelength of peak attenutation, even higher sensitivity to the cladding exterior environment has been demonstrated. We have further shown that ISAM-coated LPGs can function effectively as biosensors by using the biotin-streptavidin system and by using the Bacillus anthracis (Anthrax) antibody-PA (Protective Antigen) system. Shifts of >2 dB in the transmittance have been observed as a result of exposure to 0.0125 mg/mL of streptavidin. The results confirm that ISAM-LPGs yield a reusable, thermally-stable, and robust platform for designing and building efficient optical biosensors.
11:45 AM - E7.9
Organic Heterojunction Lateral Photoconductors for Chemical Sensing Applications.
John Ho 1 , Vladimir Bulovic 1
1 , MIT, Cambridge, Massachusetts, United States
Show AbstractThe purpose of this project is to develop solid-state, organic device structures capable of efficiently converting chemical analyte detection into an electrical signal. The main advantage to using organic materials is that they are synthetically flexible and can be tailored to respond to specific analytes. Our device structure is a hetero-structure consisting of an optically active, chemosensing layer and a charge-transport layer arranged in a lateral photoconductor-style device with bottom contacts. The advantages to physically separating the sensing and transport functions in chemical sensors are 1) the ability to optimize the transduction of luminescence to device current, and 2) the development of a reusable device platform for a variety of chemosensing applications. In addition to developing a novel device platform for chemical sensing, we are using this novel structure to study charge transport and exciton dynamics in organic thin films. The devices consist of a series of gold interdigitated fingers (W x L = 1500 µm x 4 µm) spaced 10 µm apart. The gold electrodes are photolithographically defined on glass before the organic layers are thermally evaporated. Using a PTCBI/TPD bi-layer junction we demonstrate a photocurrent to dark current ratio of over 1000 to 1. These bottom contact devices have a large surface area exposed to the environment by virtue of their lateral structure, facilitating chemical sensing. Should an exciton-quenching analyte bind with the PTCBI absorber layer, a reduction in the photocurrent ensues, thus transducing a chemical reaction into an electrical signal.
12:00 PM - E7.10
Designing Nanoshell Platforms in the Mesoscopic Regime for Chemical Sensing
Felicia Tam 1 2 , Allen Chen 2 3 , Janardan Kundu 2 4 , Hui Wang 2 4 , Naomi Halas 2 4 5
1 Dept. of Physics and Astronomy, Rice University, Houston, Texas, United States, 2 Laboratory for Nanophotonics, Rice University, Houston, Texas, United States, 3 Dept. of Bioengineering, Rice University, Houston, Texas, United States, 4 Dept. of Chemistry, Rice University, Houston, Texas, United States, 5 Dept. of Electrical and Computer Engineering, Rice University, Houston, Texas, United States
Show AbstractMetallic nanoparticles are exceptional sensing platforms due to their plasmon resonances which interact strongly with incident light at wavelengths determined largely by geometry. In recent years metallic nanoparticles have proven to be immensely useful for sensitive detection of chemical and biological species at optical and near-infrared wavelengths. Extending this rational approach to plasmonic substrate design into the mid-infrared region of the spectrum allows for the development of substrates for enhancing infrared spectroscopies and for performing ultrasensitive SPR measurements with IR laser sources. Here we report the design and development of plasmon resonant substrates in the mid-IR region of the spectrum based on the core-shell geometry of nanoshells. Increasing overall particle size of nanoshell beyond the quasistatic regime provides a useful strategy for the development of plasmon resonant substrates in the mid-IR range. In this mesoscopic regime, as the overall size of nanoshells is increased, two differing core-shell geometries provide tunable plasmon resonances at each wavelength, differing in their higher order multipolar response. Further increases in particle size lead to a transitional regime where the nanoshell properties approach the macroscopic thin film limit. We investigate the properties of individual nanoshell and aggregate nanoshell substrates specific to the mid-IR regime.
12:15 PM - E7.11
Surface-Enhanced Raman Scattering (SERS) on Novel Nanoparticles
Joseph McLellan 1 , Younan Xia 1
1 Chemistry, University of Washington, Seattle, Washington, United States
Show AbstractSince its discovery in the mid 1970’s surface-enhanced Raman scattering (SERS) has evolved in to a modern analytical tool, with applications in biomedical detection and chemical sensing. The primary enhancement in SERS is an electromagnetic (EM) enhancement that arises from the extremely high local fields due to surface plasmon resonance (SPR) of the metal substrate. The highest EM field enhancement is achieved when the irradiation wavelength is resonant with the SPR maximum. From the beginning, most efforts have focused on coinage metal substrates due to the location of their SPR bands in the visible and near infrared regions, and the common use of lasers in these regions in typical Raman spectrometers. Generally speaking, the positions of the SPR bands for metal nanoparticles can be controlled by varying the size, shape, structure, or composition of the particles. Our group specializes in the shape-controlled synthesis of metal nanoparticles with one of the main goals being the tuning of their SPR properties. This talk will illustrate how the SERS activity can be manipulated by tuning the SPR properties. We have demonstrated this with a variety of metals including Rh, Pd, and Ag. We have also investigated hollow particles generated via galvanic replacement reactions using silver nanocubes as sacrificial templates. I will discuss our observations about the SERS activities of all of these particles and how they correlate with the particles size, shape, and composition.
12:30 PM - E7.12
Highly Sensitive Surface Plasmon Resonance Sensor on Nanoscale Bioactive Surfaces for Specific Detection of Tri-Nitro Toluene.
Praveen Singh 1 , Takeshi Onodera 1 , Kiyoshi Matsumoto 2 , Norio Miura 3 , Kiyoshi Toko 1
1 Department of Electronics,Graduate School of Information science and Electrical Engineering, Kyushu University, Fukuoka Japan, 2 Graduate School of Agriculture, Kyushu University, Fukuoka Japan, 3 Art, Science and Technology Centre for Cooperative Research, Kyushu University, Fukuoka Japan
Show AbstractA highly sensitive, cost effective, nanoscale biosensor chip surface was fabricated using DNP-KLH as ligand supported by underlying amino undecanethiol(AUT) self assembled monolayer (SAM) and bis sulfosuccinimidyl suberate as crosslinker. Bioactive thin films were fabricated over gold chip via layer-by-layer self assembly methods. Biomolecular interaction between substrate specific TNP-KLH mouse Ig antibody and DNP-KLH conjugate surface was monitored through surface plasmon resonance based optical sensor for analyte detection. The quantitation of TNT was done using the solution inhibition based competitive assay. The DNP-KLH surface biosensor has shown a detection limit of 140 ppt and was sensitive enough up to 5 ppt level for TNT molecule. The detection limit of SPR biosensor was further reduced by using secondary antibody to lower ppt level for TNT analyte. A 10 mM Gly-HCl pH 2.0 solution was used for regeneration of sensor chip surface. The cross-reactivity study reveals that the assay is very specific to TNT molecule.
12:45 PM - E7.13
Photonic-Fluidic Integrated Microstructures for Sensor and Photonic Device Applications.
Claire Callender 1 , Patrick Dumais 1 , Christopher Ledderhof 1 , Julian Noad 1
1 , Communications Research Centre, Ottawa, Ontario, Canada
Show AbstractIntegrated microstructures in which light can interact with nanoscale liquid samples have many applications in chemical and biological sensors. The integration of fluid-filled microstructures with lightguiding components on a wafer can also provide novel photonic device architechtures for exploiting the unique properties of fluids or nanoparticle suspensions for applications in optical communications. In this paper, we present the design, fabrication and characterization of liquid-filled microchannels embedded in silica layers and integrated with optical waveguides. These integrated microstructures are formed using plasma-enhanced chemical vapor deposition (PECVD), photolithography and reactive ion etching (RIE). This approach requires no top sealing of the microchannels, and is compatible with large wafers, offering the potential for large device yields and low unit cost. The embedded microchannels are typically elliptical or circular in cross-section, with diameters on the order of 3 μm, offering the potential for on-chip spectroscopy of very small liquid samples (on the order of a few pl) as well as single mode propagation in novel photonic device architectures. Surface accessible ports are fabricated without additional process steps for the convenient introduction of fluids into microchannels. This unique design ensures that fluid-filled segments themselves have no open wet ends, simplifying packaging. Microfluidic circuits including bends, T-junctions and splitters are demonstrated. Coupling of light from integrated solid silica waveguides via directional coupling or direct end-fire coupling into fluid filled channels has been achieved on-chip, with the optical inputs conveniently separated from the fluid introduction points. Details of the fabrication process, the design of waveguides and microchannels and the optimization of optical coupling in the integrated microstructures will be discussed. Demonstration of various device functionalities will be presented, including sensitive refractive index sensors in different configurations, on-chip excitation of fluorescence in fluid-filled microchannels, and the use of integrated liquid waveguide segments for exploiting nonlinear and other optical properties of fluids in photonic devices.
E8: Nanowires for Biological and Chemical Detection
Session Chairs
Thomas Thundat
Anis Zribi
Wednesday PM, November 29, 2006
Room 210 (Hynes)
2:30 PM - **E8.1
Nanostructured Materials for Semiconducting Transducers and Biomimetic Recognition Layers
Oliver Hayden 1
1 , IBM, Zurich, Rüschlikon Switzerland
Show AbstractLow-dimensional materials are attractive for nanoscale transducers or nanostructured sensor layers. These materials open up new perspectives for biosensing applications, such as highly integrated sensors arrays or extremely robust receptors. Currently, the field of biosensing is dominated by devices relying on antibody recognition and fluorescence detection. Ideally, one would like to perform label-free detection with a device showing single analyte sensitivity. Furthermore, the replacement of expensive natural receptors by more robust biomimetic receptors is of interest for e.g. long-term monitoring. Here, two classes of low-dimensional materials, semiconducting nanowires and nanostructured polymer thin films, are presented for novel biosensors. Both materials are formed by self-organization mechanism and are applicable to fabricate nanoscale transducer and to mimic antibodies. Semiconducting nanowires grown by the vapor-liquid-solid mechanism are applied for ion-sensitive field-effect transistor (ISFETs). The high charge sensitivity of ISFETs with nanowire diameters in the range of the Debye-Hückel length are used to probe specifically charged bioanalytes. A general approach to man-made antibodies is described based on “bioimprint-lithography” of polymer thin films, which is performed directly on transducers to form biomimetic receptor sites. The bioimprinted sites can selectively trap analytes, such as cellular or viral species by a geometrical and molecular recognition event in even complex environments.
3:00 PM - E8.2
Silicon Nanowire Field-Effect Transistor for Biosensing
Xihua Wang 1 , Yu Chen 1 , Pritiraj Monhanty 1 , Shyamsunder Erramilli 1 2
1 Department of Physics, Boston University, Boston, Massachusetts, United States, 2 Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States
Show AbstractPlanar field-effect transistor (FET) can serve as the platform technology for biological sensors. Advances in nanotechnology have made it possible to fabricate nanoscale field-effect transistors (nano-FET) for ultra-sensitive biosensing. Here, we report preliminary results of I-V measurements of silicon nanowires fabricated from undoped silicon-on-insulator (SOI) for different reference gate voltages. An additional Al2O3 layer deposited by atomic layer deposition (ALD) on the silicon nanowire surface decreases the current leaking from the reference gate in the solution. Highly sensitive detection of conductance change due to the change in the electrical gate potential enables highly sensitive biosensing. We acknowledge support by the Department of Defense MSRP program (W81XWH-04-1-0578) and the National Science Foundation (DBI-0242697).
3:15 PM - E8.3
Gas Sensor Based on the Network of SnO2 Semiconducting Nanowires.
Young-Jin Choi 1 , Kyung-soo Park 1 , Jae-Hwan Park 1 , S. Joon Kwon 1 , Jeong-Hyun Park 1 , Jae-Gwan Park 1
1 Multifunctional Ceramics Research Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of)
Show Abstract3:30 PM - E8.4
Nanowire Bridges for Direct Digital Detection of Chemical and Biological Species.
Robert Hamers 1 , Lu Shang 1 , Bo Li 1 , Matthew Marcus 3 1 , Kevin Metz 1 , Edward Perkins 2 , Jeremy Streifer 1
1 Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States, 3 , Honeywell Automation & Control Solutions, Plymouth, Minnesota, United States, 2 Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg, Mississippi, United States
Show Abstract3:45 PM - E8.5
Bi-directional Anodization of Aluminum Wires: A Novel Template for Nanowire Sensors and Nanowire Transistors.
Travis Wade 1 , Al Dughaim Mohammed 1 , Quang Anh 1 , Mihaela Ciornei 1 , Jean-Eric Wegrowe 1
1 Laboratoire des Solides Irradies, ECOLE Polytechnique, Palaiseau France
Show Abstract4:30 PM - E8.6
Pushing the Sensitivity Limits of Nanowire Chem/Bio Sensors.
Xuan Gao 1 , Jie Xiang 1 , Gengfeng Zheng 1 , Fernando Patolsky 1 , Charles Lieber 1 2
1 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States, 2 Division of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States
Show Abstract4:45 PM - E8.7
ZnO Nanowire Based Glucose Sensors.
Chang Li 1 , Jianfeng Zang 1 , Xiaowei Sun 2 , Jianxiong Wang 2
1 School of Chemical & Biomedical Engineering, Nanyang Technological University, Singapore Singapore, 2 School of Electrical & Electronic Engineering, Nanyang Technological University, Singapore Singapore
Show AbstractA great variety of nanostructures of ZnO namely nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires and nanocages, has been synthesized under specific growth conditions. Both the richest nanostructures and unique properties of ZnO made it particular promising toward the biosensor applications. ZnO nanowires were fabricated in this work and were employed to immobilize glucose oxidase (GOD) on a gold surface for constructing a glucose sensor. Well defined redox peaks of ZnO nanowires were observed in cyclic voltammetric experiments, indicating ZnO is reversibly, electrochemically active. The sensor showed directly electrochemical oxidation of glucose on GOD/ZnO nanowire surface without addition of conventional electron mediators. The mechanism of direct electrochemical oxidation was verified by the experiment of co-immobilization of catalase into the sensor system. The novel sensor exhibited typical enzymatic reaction behavior and demonstrated a Michaelis-Menten constant of 4.19 mM, a sensitivity of 6.0 micro A.cm-2.mM-1, a linear dynamic range of up to 2.30 mM, a response time of 15 s, and a low detection limit of 0.04 mM. Due to its simplicity and high sensitivity, the sensor could have great potential applications in clinical diagnosis.
5:00 PM - E8.8
Nano ZnO UV Sensors: Enhanced Sensitivity due to Micro-spheres in a Matrix of Nanowires
Shiva Hullavarad 1 , A. Luykx 1 , P. Valdivia 1 , A. Singh 1 , D. Pugel 1 2 , R. Vispute 1 , T. Venkatesan 1
1 Center for Superconductivity Research, University of Maryland, College Park, Maryland, United States, 2 Detector Systems Branch, Goddard Space Flight Center,, NASA, Greenbelt, Maryland, United States
Show AbstractOptical studies of 1D nanostructures have focused primarily on lithographically and epitaxially defined quantum wires embedded in a semiconductor medium. In the case of ZnO sensors, devices have been fabricated by dispersing nanowires in a solution and then coating them on a substrate. Device response and decay times of >150 s have been reported by other workers. In this work, ZnO-based UV detectors are fabricated by utilizing the naturally grown combination of ZnO micro-spheres embedded in a matrix of ZnO nanowires. The nanowires play the role of interconnects while the spheres are the oxygen adsorption centers. Nanostructured ZnO with this feature eliminates the time consuming cleanroom processing of UV detectors by lithography techniques to define the interdigitated contacts. Nano-ZnO sheet is prepared by a catalyst-free direct vapor phase method. The process conditions are varied to get the nanowire-alone and the sphere-alone structures. In this method the blend of both structures has been synthesized to fabricate ultra- sensitive UV detectors.The photoresponse measurements indicate the maximum response at 386 nm, which is in close agreement with PL measurements showing the emission at 383 nm with FWHM of 14.8 nm. Interestingly, oxygen-related defect emission at 512 nm is not observed indicating the good quality of the material. Decay times were measured in the presence of UV illumination under different oxygen pressures varying from 0.1 Torr to atmospheric pressure, and they varied from 39 s to 5.2 s, respectively. The decay times for UV detectors from nanowires alone are 141 s to 15 s for the same pressure range. In this talk the efforts to enhance the sensitivity of the ZnO sensors in the context of combining sphere and wire structures will be discussed.
5:15 PM - E8.9
A Universal, Non-destructive Approach to Electrically Connecting Nanowire Arrays Using Nanoparticles - Application to a Unique Gas Sensor Architecture.
Prahalad Parthangal 1 2 , Richard Cavicchi 2 , Michael Zachariah 1 2
1 Mechanical Engineering and Chemistry, University of Maryland, College Park, Maryland, United States, 2 Process Measurements Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Show AbstractWe report on a novel, in-situ approach toward connecting and electrically contacting vertically aligned nanowire arrays using conductive nanoparticles. The utility of the approach is demonstrated by development of a gas-sensing device employing this nano-architecture. Well-aligned, single-crystalline zinc oxide nanowires were grown through a direct thermal evaporation process at 550 °C on gold catalyst layers. Electrical contact to the top of the nanowire array was established by creating a contiguous nanoparticle film through electrostatic attachment of conductive gold nanoparticles exclusively onto the tips of nanowires. A gas-sensing device was constructed using such an arrangement and the nanowire assembly was found to be sensitive to both reducing (methanol) and oxidizing (nitrous oxides) gases. This assembly approach is amenable to any nanowire array for which a top contact electrode is needed.
5:30 PM - E8.10
Development of Au Nanowires for Recording Electrical Activity in Neural Cells
Jesse Silverberg 1 , Sucharita Saha 2 , Zhen Wu 1 , Don O'Malley 2 , Latika Menon 1
1 Physics, Northeastern University, Boston, Massachusetts, United States, 2 Biology, Northeastern University, Boston, Massachusetts, United States
Show AbstractIn this work, we address critical issues related to the application of nanowire arrays in neuroscience, such as feasible wire dimension that will produce reliable recordings, consequence of neuronal motion during cell growth and recording, specific nanodevice structure and design which will produce detectable, reliable neuronal recording, and most importantly cell viability and reaction to the nanowire probe. We have prepared conducting Au nanowires with varying dimensions inside nanoporous alumina templates. Electrical and optical properties of the nanowires are studied as a function of wire dimension and their feasibility for neural recording is determined. Neural cells are cultured on the surface of the nanowire tips and cell reaction to this nanoenvironment is studied.
5:45 PM - E8.11
Detection of CO and H2 Using Metal-Oxide-Metal (MOM)Heterojunction Nanowire Sensor Devices.
Jason Tresback 1 , Alexander Vasiliev 1 , Edward Herderick 1 , Nitin Padture 1
1 MSE, The Ohio State University, Columbus, Ohio, United States
Show AbstractThere is growing interest in the field of nanoelectronic devices, where nanoscale building blocks, such as nanowires (metals, semiconductors, oxides), are fabricated in isolation and assembled into nanocircuits for a variety of applications, such as gas sensing. In the case of metal oxides, sensor devices have been fabricated using all-oxide nanostructures where the active region is difficult to control, and often limited by lithographic techniques. Novel metal-oxide-metal (MOM) heterojunction nanowires, where two metal nanowires (50 to 100 nm diameter; Au or Pt) are separated by a nanoscale segment (50-100 nm length) of a functional oxide, provide the opportunity to compare sensing behavior of devices where the size and composition of the active region can be better controlled. We have introduced a generic, template-based method for the synthesis of MOM nanowires in systems Au-oxide-Au (where oxide=SnO2, TiO2, ZnO, NiO, or Fe2O3). Here the metal interconnects are integrated within the building block making them more suitable for large-scale assembly, as well as providing Schottky junctions and catalyst sites at the nanoscale. Furthermore, our synthesis method provides great control over the geometry and composition of the MOM nanowires. By virtue of the nanoscale nature of the MOM nanowires, the chemical-sensor devices made using MOM building blocks are expected to be highly sensitive, selective, and operate at low voltages and temperatures. Here we report the detection of H2 and CO at low temperatures using single MOM nanowire devices where the active regions have different size (100-500 nm) and composition (SnO2 and TiO2). By collecting size- or composition-dependent responses, several single nanowire devices can be used together to achieve better selectivity. Results from device fabrication and sensor-properties measurements of various MOM nanowires will be presented, together with a discussion of relevant mechanisms.
E9: Poster Session: Nanomaterials/Nanotransduction for Biological and Chemical Detection
Session Chairs
Changming Li
Larry Nagahara
Magnus Willander
Anis Zribi
Thursday AM, November 30, 2006
Exhibition Hall D (Hynes)
9:00 PM - E9.10
AAO Nanowells: Synthesis, in-situ Growth Study, and Applications in Ultra-sensitive Chemical Detection.
Hau Wang 1 , Kyung-In Son 1 , Byeongdu Lee 2 , Jianjiang Lu 1 , Catherine Han 1
1 Materials Science Division, Argonne National Laboratory, Argonne, Illinois, United States, 2 X-Ray Science Division, Argonne National Laboratory, Argonne, Illinois, United States
Show Abstract9:00 PM - E9.11
Controlling Organic Electrochemical Transistors with Ion Channels.
Daniel Bernards 1 , Gilman Toombes 2 , Sol Gruner 2 3 , George Malliaras 1
1 Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 2 Physics, Cornell University, Ithaca, New York, United States, 3 Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York, United States
Show AbstractOrganic electrochemical transistors (OECTs) have recently gained interest as a platform for sensing applications given their low cost, ease of processing and compatibility with a variety of systems. In their simplest form, the conductivity of an organic semiconductor is modulated by application of a bias through an electrolyte; however, without functionalization, OECTs cannot effectively sense uncharged analytes or discriminate between ion types, and in general they lack specificity. A possible route to introduce specificity is to introduce bilayer lipid membranes (BLMs), where specificity is determined by the addition of ion channels. In this way, an OECT acts to amplify ionic currents that are governed by the behavior of a particular ion channel. We have incorporated bilayer lipid membranes into typical OECT devices as a means to control device characteristics. When a BLM is formed, normal gating of an OECT is suppressed due to the low permeability of BLMs to ionic charge. Upon the addition of gramicidin, a simple ion channel, gating can be restored. Furthermore, it is trivial to show differentiation between monovalent and divalent cations given the valence-dependant permeability of gramicidin. This is a clear demonstration of how ion channel characteristics can be directly manifested in the overall device response. In this way, our work shows that ion channels can be successfully used to control the selectivity of OECTs.
9:00 PM - E9.12
All-optical Nanoscale pH meter using Surface Enhanced Raman Scattering on Gold Nanoshells.
Carly Levin 1 , Sandra Bishnoi 1 , Christopher Rozell 1 , Muhammed Gheith 1 , Bruce Johnson 1 , Don Johnson 1 , Naomi Halas 1
1 Chemistry, Rice University, Houston, Texas, United States
Show AbstractWe show that an Au nanoshell with a pH sensitive molecular adsorbate functions as a standalone, all-optical nanoscale pH meter that monitors its local environment through the pH-dependent surface enhanced Raman scattering (SERS) spectra of the adsorbate molecules. Moreover, we also show how the performance of such a functional nanodevice can be quantitatively assessed. The complex spectral output is reduced to a simple device characteristic by application of a locally linear manifold approximation algorithm. The average accuracy of the nano-“meter” was found to be ± 0.10 pH units across its operating range.
9:00 PM - E9.13
Plasmonic Nanostructures with Reduced Symmetry and Their Sensing Applications
Hui Wang 1 4 , Peter Nordlander 2 3 4 , Naomi Halas 1 3 4
1 Department of Chemistry, Rice University, Houston, Texas, United States, 4 Laboratory for Nanophotonics, Rice University, Houston, Texas, United States, 2 Department of Physics , Rice University, Houston, Texas, United States, 3 Department of Electrical and Computer Engineering, Rice University, Houston, Texas, United States
Show AbstractSymmetry-breaking can introduce dramatic changes in the optical properties of the plasmonic nanostructures, significantly influencing their properties relevant for sensing applications. Here we have designed and fabricated two plasmonic core-shell metallodielectric nanostructures with reduced symmetry: prolate nanoshells known as nanorice and nanoshells with an offset core known as nanoeggs. Both nanorice and nanoeggs possess highly geometrically tunable plasmon resonances as well as intense local field enhancements that are much larger than those of spherical concentric nanoshells. The unique plasmonic properties of nanorice and nanoeggs are highly attractive for the control and optimization of sensing processes based on surface plasmon resonance sensing or surface-enhanced spectroscopies. Invoking the Plasmon Hybridization model as a design principle for these experimentally realized nanostructures provides a thorough understanding of the plasmon resonance energy landscape of these complex nanostructures. The resulting near and far field optical properties of nanorice and nanoeggs determine their effectiveness as sensing substrates for surface plasmon resonance and surface-enhanced Raman spectroscopy.
9:00 PM - E9.14
Self-assembled Fibrous Gels from Modified di-peptides for 3D Cell-culture.
Vineetha Jayawarna 1 , Julie Gough 1 , Rein Ulijn 1
1 School of Materials , University of Manchester, Manchester United Kingdom
Show Abstract9:00 PM - E9.15
Fabrication of Nanostructured Thin Film Electrodes with Arrayed High Electroactive Sites
Aijun Yin 1 , Jin Ho Kim 1 , Jimmy Xu 1
1 Engineering, Brown University, Providence, Rhode Island, United States
Show AbstractNanostructured materials, with two-dimensional ordered nanopore or nanorod arrays, have drawn much attention because of their potential applications in optical, electronic, and chemical/electrochemical fields, such as photonic and opto-electronic devices, gas- or bio-sensors, catalysis, and high density magnetic media. In this work, we demonstrate a method for fabricating bilayered thin film electrodes with high electroactive reaction sites. The electrodes were prepared from metallic films with highly ordered nanorod/nanotube arrays deposited onto anodic aluminum oxide (AAO) templates through e-beam evaporation. First, highly ordered AAO films were obtained by anodizing pure Al sheets in 0.3 M oxalic acid solution at 40 V and 10 C via a two-step method. Second, two layers of metal films (Al and Au) were evaporated onto the AAO substrates consecutively. Then, free standing metallic films were obtained by chemically removing the AAO templates in a mixture of phosphoric acid and chromium oxide. Finally, electrodes were formed by transferring the metallic films onto electrode holders/substrates followed by oxidizing the Al layer to obtain an insulating layer on the Au film while leaving the tips of Au nanorods/nanotubes exposed as the electrochemical/sensing sites. The highly ordered reactive sites and the flexibility of the metallic films provide us a good platform for bio or chemical sensing, such as DNA or biomolecule detection.
9:00 PM - E9.16
Silicon-based Photonic Crystal Gas Sensors.
Torsten Geppert 1 , Andreas von Rhein 1 , Stefan Schweizer 1 , Susanne Hartwig 2 , Jürgen Wöllenstein 2 , Armin Lambrecht 2 , Ralf Wehrspohn 1
1 Department of Physics, University of Paderborn, Paderborn Germany, 2 , Fraunhofer Institute for Physical Measurement Techniques, Freiburg Germany
Show Abstract9:00 PM - E9.17
Fourier-Transform Infrared Characterization of Tin Oxide Microfiber Synthesis
Yu Wang 1 2 , Idalia Ramos 1 , Jorge Santiago-Avilés 2
1 Department of Physics and Electronics, University of Puerto Rico, Humacao, Puerto Rico, United States, 2 Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractTin oxide is a binary semiconducting oxide with a large bandgap, and has been used extensively in sensors and optoelectronic devices. Fibrous tin oxide is superior than thin film shape for its sensor applications because of its higher surface-to-volume ratio and its restriction to the grain size growth. The authors synthesized tin oxide micro- and nano- fibers from a precursor solution of poly(ethylene oxide), chloroform and dimethyldineodecanoate tin (C22H44O4Sn) using electrospinning and metallo-organics decomposition techniques. This paper uses Fourier-transform infrared (FTIR) spectroscopy to reveal a series of changes in atomic bonding from the starting precursor chemicals to the final product of fibers: the disappearance of C-Cl bonding during the electrospinning indicates the evaporation of chloroform; during the sintering, the remaining organic groups are pyrolized and the Sn-C bond in C22H44O4Sn was replaced by the additional Sn-O bond, which finally leads to the formation of tin oxide in the rutile structure. The FTIR results are consistent with and complementary to those revealed by other characterizations such as x-ray diffraction.
9:00 PM - E9.18
Spreading of Water Drops on Vertically Aligned Si Nanorod Arrays.
Jianguo Fan 1 2 , Yiping Zhao 1 2
1 Physics and Astronomy, University of Georgia, Athens, Georgia, United States, 2 Nanoscale Science and Engineering Center, University of Georgia, Athens, Georgia, United States
Show AbstractThe spreading of a water drop is affected by both the surface roughness and the surface chemical composition. The liquid-nanostructure interaction is very important for nanobiotechnology such as immobilization of biomolecules onto nanostructures. We have investigated the dynamic spreading of water drops on vertically aligned Si nanorod arrays with a fast CCD camera. A precursor film was detected advancing ahead of the contact line during the spreading. Both the diameters of the precursor film and the contact line Dc and Dp were found to obey the dynamic scaling laws at early stage of spreading, Dc,p ∝tnc,p with nc ≈ 0.108 and np ≈ 0.135 for nanorod height h = 1100 nm. When changing the nanorod height, these exponents did not vary significantly. At late stage of the spreading, the precursor and the contact line slowed down and finally reached their maxima. A model including the competition of the spreading and evaporation and the liquid transportation between the apparent water drop and the precursor film was proposed.* This work is supported by NSF
9:00 PM - E9.19
Synthesis and Self-assembly of Hybrid Rod-like Nanostructures.
Bishnu Khanal 1 , Eugene Zubarev 1
1 Chemistry, Rice University, Houston, Texas, United States
Show Abstract9:00 PM - E9.2
Mesoporous Bragg Reflector Color Tunable Sensor.
Sung Yeun Choi 1 , Marc Mamak 1 , Geoffrey Ozin 1
1 Chemistry, University of Toronto, Toronto, Ontario, Canada
Show AbstractThe photonic crystals have been shown to be an incredibly versatile platform for color sensing a range of chemical and biochemical analytes due to their ability to convert chemical/biological recognition into the optical signal. The variation in its refractive index driven by introducing guests into its matrix is the key of sensing in this system. Herein we report a self-assembly synthesis, structural and optical characterization of a new class of diffractive optical materials, called mesoporous Bragg reflectors (MBR), targeted for chemo-optical sensing applications. Investigation of the optical response of MBR to the infiltration of various organics to its pores, represented by alcohols and alkanes, reveals that MBR have better sensitivity and selectivity than conventional Bragg reflectors based upon a single layer of mesoporous material.
9:00 PM - E9.20
Plasmonic and Diffractive Coupling in 2D Arrays of Nanoparticles produced by Electron Beam Lithography.
Erin McLellan 1 , Linda Gunnarrsson 2 , Mikael Käll 2 , Shenlgi Zou 1 , Richard Van Duyne 1 , George Schatz 1 , Kenneth Spears 1 , Tomas Rindzevicius 2
1 Chemistry, Northwestern University, Evanston, Illinois, United States, 2 Applied Physics, Chalmers University of Technology , Gothenburg Sweden
Show AbstractNanofabrication is one of the driving forces leading to developments in a variety of fields including microelectronics, medicine, and sensors. Precise control over nanoscale architecture is an essential aspect in relating new size-dependent material properties. Both direct write methods and natural lithography’s offer a unique opportunity to fabricate “user-defined” writing of nanostructures in a wide range of materials. Electron Beam Lithography (EBL) and Nanosphere Lithography (NSL) provide the opportunity to fabricate precise nanostructures on a wide variety of substrates with a large range of materials. Using electrodynamics calculations, Schatz and coworkers have discovered one and two dimensional array structures that produce remarkably narrow plasmon resonance spectra upon irradiation with light that is polarized perpendicularly to the array axis. In order to investigate these interactions, precise control of nanoparticle orientation, size, shape and spacing is necessary. If the overall structures have excessive defects then the effect may not be seen. For the two dimensional arrays, to have the best control over array fabrication and to look at these interactions experimentally, EBL was used to construct both hexagonal arrays of circular cylinders and the Kagome lattice. The interparticle spacing in each of these structures was varied systematically. Dark field microscopy was used to look at overall sample homogeneity and collect the single particle plasmon resonance spectrum. Additionally, both dark-field and extinction spectroscopies were used to look at the bulk spectral properties of each array type and each spacing. In investigating of the two dimensional arrays, the Kagome structure was also compared to samples produced by traditional NSL to study the optical interaction of defects, domains, and overall sample uniformity on the shape and location of the plasmon resonance. This work illustrates a deeper understanding in the nature of the optical coupling in nanostructures and this knowledge can be utilized in the future to fabricate designer (tailor made) substrates for plasmonic and surface-enhanced raman applications.
9:00 PM - E9.21
Gold Nanorods and Biomolecule Conjugates for Remote Control of Localized Gene Expression by Near Infrared Irradiation
Chia-Chun Chen 1 2 , Yi-Shin Liu 1 , Dee-Yan Wang 1
1 Department of Chemistry, National Taiwan Normal University, Taipei Taiwan, 2 Institute of Atomic and Molecular Science, Academia Sinica, Taipei Taiwan
Show AbstractThe conjugates of gold nanorod and the gene of enhanced green fluorescence protein (EGFP) have been prepared for the remote control of gene expression in living cells. The conjugates were characterized by the UV-vis spectroscopy, electrophoresis and transmission electron microscopy (TEM) to study their optical and structural properties before and after femto-second near infrared (NIR) laser irradiation. The gold nanorods of EGFP-GNR conjugates underwent shape transformation after NIR irradiation, that resulted in the release of EGFP DNA. When EGFP-GNR conjugates were delivered to cultured HeLa cells, induced GFP expression was specifically observed in cells that were locally exposed to NIR irradiation. Our results demonstrate the feasibility of using gold nanorods and NIR irradiation as means of remote control of gene expression in specific cells. This remote activation system is applied for other biological and medical studies and will be discussed in the presentation.
9:00 PM - E9.22
Formation of Mesoporous Silica Thin Films on Metal Substrates and Use as Electrodeposition Templates to form High Surface Area Nanowire-Networks.
Martin Bakker 1 2 , Roger Campbell 2 , Jason Manning 1 2 , Dong Ryeol Lee 3 , Xuefa Li 3 , Jin Wang 3
1 Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Alabama, United States, 2 Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama, United States, 3 Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States
Show AbstractThere is considerable interest in the development of sensors utilizing electrochemical detection on high surface area electrodes and resistance changes in nanowires and nanowire networks. Mesoporous silica of various nanophases can be used as electrodeposition templates to form high surface nanowire arrays and nanowire networks. Electrodeposition into mesoporous silica thin films has been used successfully for some time on Indium Tin Oxide glass substrates. However, there has been no report of mesoporous silica formation on metal substrates. It is possible that this reflects the lack of adhesion of mesoporous silica films to substrates such as gold, or it may reflect the expectation that the very acid nature of the synthesis would dissolve the underlying metal. We have demonstrated that it is possible to form 2-D cubic and 3-D hexagonal mesoporous silica films on a wide range of metals including nickel, copper, ruthenium, tungsten, silver and tantalum. Grazing Incidence Small Angle X-ray Scattering shows that the films are sufficiently well ordered to show diffraction spots, and that the mesoporous silica films survive removal of the template and electrodeposition of nickel and cobalt into the mesoporous silica films. This approach has also be used on three dimensional rather than planar substrates. After electrodeposition of nickel, hydrogen fluoride can be used to remove the silica leaving high surface area bicontinuous networks with 5 nm feature size. Electrochemical evaluation shows surface area increases of 140 fold.
9:00 PM - E9.23
Fluorescent Labeling of Repetitive Polypeptides
Oxana Vassiltsova 1 , Seiichiro Higashiya 1 , Natalya Topilina 1 , Marina Petrukhina 1 , John Welch 1
1 Chemistry, University at Albany, SUNY, Albany, New York, United States
Show AbstractBiosystems are highly organized from molecular-scale building blocks such as proteins with intricate hierarchical architectures and represent unparalleled examples of bottom-up assembly. Biological molecules often possess highly specific and precise molecular recognition capabilities that can be programmed through genetic engineering and can exert rational control over inorganic material assembly, and pattern formation at a molecular scale. Integration of these unique capabilities of biomolecules with the design of new materials can offer many opportunities for nanofabrication including rational molecular design through spatial control on a nanometer scale, and hierarchical assembly of two-dimensional complex architectures. We demonstrate the self-assembly of QDs on the surface via interactions of water-soluble CdSe/ZnS QDs with polyhistidine residues of repetitive polypeptides serving as templates. Interaction of QDs with dye-labeled polypeptides in these conjugates were tested and characterized by Laser Scanning Confocal Microscopy, AFM and TEM.
9:00 PM - E9.25
Investigation of the sensitivity of Two-photon Fluorescent Polymers for Organic Nitrogen-rich compounds
Aditya Narayanan 1 , Oleg Varnavski 2 , Timothy Swager 3 , Theodore Goodson 2
1 Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan, United States, 2 Chemistry, University of Michigan, Ann Arbor, Michigan, United States, 3 Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractThe use of new conjugated organic compounds for sensor applications has evolved to the development of novel conjugated fluorescent polymers.1 The creation of such conjugated polymers as poly(phenylene ethynylene)s and (phenylene vinylene)s for amplified fluorescent sensing has been reported to demonstrate impressive sensing for energetic nitrogen-rich compounds.1,2 The effects have been carried out utilizing linear(one-photon) fluorescence quenching measurements. A novel approach which utilizes the additional sensitivity of non-linear optical methods involves two-photon excited fluorescence.3 This technique, in combination with the great sensitivity of various organic polymers offers an impressive development in the sensing technology. In this presentation, two conjugate polymers will be discussed which show impressive two-photon properties. The linear and non-linear optical absorption cross-sections for the two polymers are provided. The fluorescence lifetimes and Stern Volmer plots are discussed in regards to the sensing properties of these promising two-photon fluorescent polymers.
9:00 PM - E9.26
Multi-Layered Organic Light Emitting Diode Based Bio-Chemical Sensor
Sandeep Devabhaktuni 1 , Sunil K Penna 1 , Sudhaprasanna Padigi 1 , Shalini Prasad 1
1 Electrical and Computer Engineering, Portland State University, Portland, Oregon, United States
Show Abstract9:00 PM - E9.27
Preparing Nanopore Structures for Biosensing.
Subhasish Chatterjee 1 , Miriam Ginzberg 2 , Bonnie Gersten 1
1 Chemistry, The Graduate Center, CUNY and Queens College, Flushing, New York, United States, 2 Chemistry , Queens College, Flushing, New York, United States
Show AbstractNanopore structures play a promising role in the development of nanomechanical, nanoelectrical and biosensing devices. In recent years, voltage-driven transport of polynucleic acids (e.g. DNA, RNA) across the synthetic inorganic nanopores has been investigated as a step towards the development of potential nanoscale biosensing devices. In addition, nanopores are expected to be utilized as chemical and gas sensors. TiO2 and SiO2 are promising materials which can have a wide range of applications in nanopore based sensors. In this study, TiO2 and SiO2 nanopores were prepared by the electrochemical anodization. During the anodization process, titanium and silicon were converted to their respective oxide forms. The element of interest was used as the anode, while platinum was used as the cathode in an electrochemical cell. Hydrofluoric acid solution was utilized as the electrolyte. A comparison of their pore structures at the same physical conditions of synthesis process, such as, concentration of electrolyte (0.5– 2%), time of anodization (10-30 min), was evaluated. The production of the oxide metal was confirmed by XRD (X-ray diffraction). The resulting nanopore structure was characterized by scanning electron microscopy (SEM). In spite of similarities in the synthesis process, there are differences in the formation mechanisms of TiO2 and SiO2 nanopores.
9:00 PM - E9.28
Label Free Polydiacetylene Sensor Chip for Detection of E.coli
Hyun Choi 1 , Kyung-Woo Kim 1 , Jung Eun Son 1 , Min Kyu Oh 1 , Dong June Ahn 1 , Gil Sun Lee 1 , Jong-Man Kim 2
1 Chemical & Biological Engineering, Korea University, Seoul Korea (the Republic of), 2 Chemical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractDiacetylene molecules have been of great interest to mimic the self-organization and functionalization of the cell membrane. Self-organization of diacetylene monomers into supramolecular assemblies gives rise to prepare polymerized vesicles and films by irradiation with 254 nm UV light. Ploydiacetylene (PDA) supramolecules initially blue undergo a visible color transition from blue to red due to various environmental perturbation including temperature, pH, solvent, mechanical stress and so on. The color transition occurs when external stimuli impose stresses altering delocalization length of π electrons along polydiacetylene backbones.Many studies using polydiacetylene supramolecules have been reported mostly about detection either in vesicle solutions or in LB films. In this study, for the first time we immobilized and patterned PDA vesicles on solid substrate using micro arrayer, which have moieties to react with antibodies for E.coli detection. Immobilized vesicle system was developed since it possesses many advantages in multiple screening, durable stability, and higher sensitivity. We confirmed immobilized PDA vesicles could selectively detect only E.coli, based on the fact that PDA vesicles showed self-emitted red fluorescence in reaction with E.coli, but no fluorescence against Bacillus subtillus. In addition, E.coli without antibody moiety did not induce fluorescence signal. These results strongly suggest that the PDA vesicles have great potentials to be applied to a label free cell chip which can detect various pathogens.
9:00 PM - E9.29
Enhanced Photocactalytic Activities under Visble Light Irradiation of Nitrogen-doped Titanium dioxide Nanoparticles by A Two-Step Method
Shen Yanfang 1 , Xiong Tianying 1 , Yang Ke 1
1 , Institution of Metal Research, Chinese Academy of Sciences, Shenyang China
Show Abstract9:00 PM - E9.3
Luminescent Colloidal Nanocrystals in Micelles for Bioconjugation.
Nicoletta Depalo 1 2 , Antonella Mallardi 1 , Roberto Comparelli 1 , Maria Lucia Curri 1 , Striccoli Marinella 1 , Angela Agostiano 1 2
1 IPCF, CNR , Bari Italy, 2 Chemistry, Università di Bari, Bari Italy
Show AbstractColloidal nanocrystals (NCs) provide exciting building blocks for nanoscale assemblies, structures and devices. Interestingly, such nanoparticles show original optical, electrical and catalytic properties and share their dimensional range with biomolecules, such as enzyme, antigens, antibodies and DNA. This similarity could allow the integration of nanomaterials with biological molecules. The conjugation of nanoparticles and biomolecules, with elaborate molecular architectures and recognition characteristics, can provide a new class of hybrid nanomaterials. Such objects can be organized in 2/3 D and used for (bio) sensing, labelling, analytical applications and in bioelectronic devices. Hydrophobic surfactant capped CdSe@ZnS NCs have been incorporated in phospholipid block copolymer micelles, using modified phospholipids. The obtained water soluble micelles have been cross-linked, by means of a suitable bifunctional agent, with Bovine Serum Albumin (BSA). The resulting system has been extensively characterized by optical (UV-VIS, PL, FT-IR), structural (TEM) and electrophoretic techniques. In addition, Dinamic Light Scattering (DLS) has been employed to determine the size of NC containing micelles before and after the bioconjugation. The experimental results indicate that the NC emission properties are retained, that no NC aggregation phenomena occur and that, finally, such system is highly stable in time thus resulting particularly appealing for application in biological domains.This work has been partially funded by EC through project NaPa (contract no. NMP4-CT-2003-500120)
9:00 PM - E9.30
Preparation of Polymeric pH Sensors Based on Fluorescence Resonance Energy Transfer.
Sung Woo Hong 1 , Jea Uk Lee 1 , Cheol-Hee Ahn 1 , Won Ho Jo 1
1 Hyperstructured Organic Materials Research Center and School of Materials Science and Engineering, Seoul National University, Seoul Korea (the Republic of)
Show Abstract9:00 PM - E9.31
The Effect of the Conjugation of Nanoparticles on the Stability of Biotin-Streptavidin Complex
Subhasish Chatterjee 1 , Gina Moriarty 2 , Bonnie Gersten 1
1 Chemistry, The Graduate Center, CUNY and Queens College, Flushing, New York, United States, 2 Chemistry, Queens College, Flushing, New York, United States
Show AbstractBiosensing devices function on the basis of the specific and selective molecular recognition process of biomolecules associated with nanostructured materials. The molecular recognition event depends on the conformational stability and native binding capacity of biomolecules. In this study we investigated the effect of conjugated nanoparticles on the characteristic recognition process of streptavidin-biotin complex. Gold, silver and CdS nanoparticles were synthesized in aqueous solution maintaining the size range of 20–60 nm. The biotin was conjugated with nanoparticles and its binding property to streptavidin was studied by UV-vis and fluorescence spectroscopy. On account of binding with streptavidin, the characteristic shift in the spectra of biotin conjugated nanoparticles were monitored. The effect of conformational change of nanoparticle-conjugated-protein was examined by TEM (Transmission electron microscope), and SEM (scanning electron microscope). The study indicated that size and composition of nanomaterials exert a variable effect on the molecular recognition property of biomolecules, and hence, modulate the stability of biotin-streptavidin complex.
9:00 PM - E9.32
Graphidyne Networks as Symmetric, Two-Photon Absorbing Materials.
Ajit Bhaskar 1 , Ramakrishna Guda 2 , Michael Haley 3 , Theodore Goodson 2 1
1 Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan, United States, 2 Department of Chemistry, University of Michigan, Ann Arbor, Michigan, United States, 3 Department of Chemistry, University of Oregon, Eugene, Oklahoma, United States
Show Abstract Extensive efforts have been expended to understand the structure property relationships in order to develop novel materials with large Two-Photon Absorption (TPA) cross sections1. However, the influence of molecular symmetry remains one of the less explored aspects. In this report, we have investigated the influence of molecular symmetry on the Two-Photon Absorption (TPA) behavior using six graphidyne motifs as model compounds. Such model compounds allow us to study the effect of symmetry without the addition of strong donor or acceptor groups. All the molecules have diphenyl butadiyne as the basic building block2. Theoretical calculations have shown that network annulenic structures present the possibility of formation of highly delocalized excited states by virtue of strong intramolecular interactions3. Molecular symmetry plays a vital role in this as it has a profound impact on the nature of optical excitations such as the fundamental π-π* excitation. We have systematically varied the molecular symmetry from C3h in molecule 1 (triangle) to D3h in molecule 6 (Radiation Symbol). Their TPA cross-section spectra were measured using femtosecond-pulsed lasers. Their excited state characteristics were studied using transient absorption spectroscopy. We found that the TPA cross sections (δ) increased with increasing order of symmetry. In order to understand these results using the sum over states (SOS) formalism, we calculated their ground state Mge and excited state Mee' dipole moments. The trend observed in Mge alone was insufficient to explain the trend observed in δ. However, there was a correlation between molecular symmetry and Mee', explaining the enhancement of δ. We believe that understanding the impact of molecular symmetry on TPA behavior opens a new avenue towards designing and developing novel organic materials with enhanced TPA cross sections. References:(1) Goodson, T. III. Acc. Chem. Res., 2005, 38, 99.(2) Wan, B. W.; Haley, M. M. J. Org. Chem. 2001, 66, 3893.(3) Anand, S.; Varnavski, O.; Marsden, J. A.; Haley, M. M.; Schlegel, B. H.; Goodson, T. III J. Phys. Chem. A 2006, 105, 1305.
9:00 PM - E9.33
Mechanoluminescence Studies upon Single Nanoparticles by AFM-photomeasurement System.
Nao Terasaki 1 , Kazufumi Sakai 1 , Toshiaki Koga 1 , Chengzhou Li 1 , Yusuke Imai 1 , Hiroshi Yamada 1 , Yoshio Adachi 1 , Keiko Nishikubo 1 , Chao-Nan Xu 1
1 , National Institute of Advanced Industrial Science and Technology (AIST), Tosu Japan
Show AbstractThe mechanoluminescence (ML) material in the elastic region is a noble material, which was developed in our laboratory for the first time, and can give intensive visible light emission during the application of mechanical stress, for example displacement, friction, impact and so. From the previous works, we have obtained the important results listed as below.1. High stress-photon conversion efficiency has been realized.2. The intensity of ML is proportional to the energy of stress which is applied to the material. 3. The preparation of ML particles in the nanometer order has been succeeded.By using this material as stress probes, 2 (or may be 3) dimensional stress distributions can be visualized directly and dynamically. From the viewpoint, one of the killer applications of this material has been, and will be, recognized to monitor the stress distribution of plants and structures from the viewpoint of safety maintenance and reliability improvements. So in this study, we focus a single ML nanoparticle, which determine the spatial resolution on the ML distribution sensing system, and the destructive and emission properties upon the single ML material were investigated by the AFM system with photo-measurement system.Europium doped strontium aluminate (denoted as SrAl2O4:Eu, or SAO-E) nano-, and micro-particles were used as a ML material, because SAO-E was one of the most efficient ML material at this time. The size of SAO-E nano-, and micro-particles are ca 40 nm and 1-5 μm, respectively. The procedures of the experiment are shown below. At first, the single SAO-E particle on glass plate was observed by AFM and the position of the particle was confirmed. Next, the load power (from several μN to several tens of μN) was applied to the SAO-E particle by the cantilever of AFM in the force-curve measuring mode, and the destructive and emission properties upon the single ML material were observed. With the application of the load to the SAO-E micro-particle repeatedly, most of the particle were destructed and the sizes went down until about 50 nm. On the other hand, under the 50 nm of particle size, the destruction of particle was not observed any further. Further, from the investigation of the independence of the load power on destruction, we found that most of SAO-E micro-particles were destructed with several μN load power by the AFM cantilever independently of the particle size. In the presentation, we will discuss the emission properties from the single SAO-E nanoparticle.
9:00 PM - E9.34
Substitution and Elimination Reactions of Alkyl Halides in Faujasite-X Zeolite.
Charles Kanyi 1 , David Doetschman 2 , Kaking Yan 3
1 Chemistry, Binghamton University, Binghamton, New York, United States, 2 Chemistry, Binghamton University, Binghamton, New York, United States, 3 Chemistry, Binghamton University, Binghamton, New York, United States
Show Abstract9:00 PM - E9.35
Physically Self-assembled Au Nanorod Arrays for SERS
Motofumi Suzuki 1 , Kaoru Nakajima 1 , Kenji Kimura 1 , Takao Fukuoka 2 , Yasushige Mori 3
1 Department of Micro Engineering, Kyoto University, Kyoto, Kyoto, Japan, 2 , JST Kyoto Pref. CREATE, Seika, Kyoyo, Japan, 3 Department of Chemical Engineering and Materials Science, Doshisha University, Kyou Tanabe, Kyoyo, Japan
Show AbstractRecently, we have demonstrated the direct formation of Ag nanorods with a quasi-parallel major axis on a template layer of SiO2 having a strongly anisotropic surface morphology[1]. Those Ag nanorods show excellent surface enhanced Raman scattering (SERS) properties [2]. From the practical viewpoints, however, chemically stable Au is preferred to Ag. In this presentation, we report that the physically self-assembled Au nanorod arrays show the fairly high sensitive SERS properties comparable to those of Ag.Template layers of SiO2 were prepared by the serial bideposition technique (SBD) on a glass substrate. During the SBD, the deposition angle measured from the surface normal was fixed at an angle of 79°, while the azimuthal angle was changed rapidly by 180° with each deposition of a 10-nm-thick layer. After repeating 50 cycles of the serial bideposition, Au was evaporated at a deposition angle of 73° onto the fabricated template layer. Owing to the self-shadowing, Au nanorods aligned in such a way where their major axes are parallel with each other. Strong SERS peaks were observed for the samples prepared on the SiO2 template. The elongated shapes and the isolation of the nanorods are essential for the strong enhancement of the SERS.This work was supported by The 21st Century COE Program ``Center of Excellence for Research and Education on Complex Functional Mechanical Systems'' and the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (B), 17310073, 2005.References[1] M. Suzuki, W. Maekita, K. Kishimoto, S. Teramura, K. Nakajima, K. Kimura and Y. Taga, Jpn. J. Appl. Phys. 44, L193 (2005).[2] M. Suzuki, W. Maekita, Y. Wada, K. Nakajima, K. Kimura, T. Fukuoka and Y. Mori, Appl. Phys. Lett. 88, in press (2006).
9:00 PM - E9.36
Highly Selective Hydrogen Sensing with Pt-functionalized ZnO Thin Films and Nanorods
Li-Chia Tien 1 , Hung-Ta Wang 2 , Byoung-Sam Kang 1 , David Norton 1 , Fan Ren 2 , Stephen Pearton 1
1 Materials Science and Engineering, University of Florida, Gainesville, Florida, United States, 2 Chemical Engineering, University of Florida, Gainesville, Florida, United States
Show AbstractThe hydrogen sensing property is found to be greatly enhanced by Pt-functionalized ZnO nanorods. The addition of sputtered-deposited Pt clusters to the surface of ZnO nanorods produces a significant increase in sensitivity for hydrogen detection at room temperature. A comparison is made of the sensitivities for detecting hydrogen with Pt-functionalized single ZnO nanorods and thin films of various thicknesses (20-350 nm). The Pt-functionalized single nanorods show a current response approximately a factor of three larger at room temperature upon exposure to 500ppm H2 in N2 than the thin films of ZnO. The optimum ZnO thin film thickness under our conditions was between 40-170 nm, with the hydrogen sensitivity falling off outside this range. The nanorod sensors show a slower recovery in air after hydrogen exposure than the thin films, but exhibit a faster response to hydrogen, consistent with the idea that the former adsorb relatively more hydrogen on their surface. Both ZnO thin films and nanorods show no response to oxygen. The power consumption with both types of sensors can be very small (in μW range). The results show that Pt-functionalized ZnO nanorods could be used for practical applications in hydrogen-selective sensing at ppm levels.
9:00 PM - E9.38
Sn Catalyzed Synthesis of Si/ZnS Composite Nanostructures.
Chen Zhen Hua 1
1 , City University of Hong Kong, Hong Kong Hong Kong
Show AbstractOne dimensional semiconductor nanowire heterostructures are attracting much attention due to their potential for optoelectronic nanodevice applications. In this work, silicon and ZnS composite nanowires were prepared via simple thermal evaporation of a powder mixture of ZnS and SiO with a Sn catalyst. At 1300 degree, uniform Si/ZnS coaxial nanowire heterostructure are grown on silicon substrates. Both silicon and ZnS are single-crystalline, and there is a sharp interface along the axial direction. At 1100 degree, only ZnS nanocones with catalyst tin were synthesized, theoretical analysis reveals that the nonuniform cross sections of nanocones are related to the continuous change of liquid droplet’s dimensions resulting from the supply of Sn during the evaporation. According to microstructural characterization and dimension analysis, formation mechanisms of the uniform Si/ZnS bi-coaxial nanowire and ZnS nanocones were discussed.
9:00 PM - E9.4
Hydrothermal Synthesis of Nanorods/Nanoparticles TiO2 for Photocatalytic Activity and Dye-sensitized Solar Cell Applications
Sorapong Pavasupree 1 2 , Susumu Yoshikawa 1
1 , Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan, 2 Department of Materials and Metallurgical Engineering, Faculty of Engineering, Rajamangala University of Technology Thanyaburi , Klong 6, , Pathumthani, Thailand
Show AbstractSynthesis and characterization of one-dimensional nanostructured materials (nanotubes, nanorods, and nanowires) have received considerable attention due to their unique properties and novel applications. TiO2 has been widely used for various applications such as a semiconductor in dye-sensitized solar cell, water treatment materials, catalysts, gas sensors, and so on. In our previous works, nanofibers TiO2 were synthesized by hydrothermal and post heat-treatments from natural rutile sand, however, nanofibers TiO2 had rather low surface area (10-20 m2/g). In this study, nanorods/nanoparticles TiO2 with mesoporous structure (with much higher surface area, 203 m2/g) has been synthesized, which shows high photocatalytic activity and high performance in dye-sensitized solar cell. The detail microstructure, photocatalytic, and photovoltaic properties will be reported. X-ray diffraction patterns were rather sharp, which indicated the obtained TiO2 had relatively high crystallinity, and attributable to the anatase phase. SEM image of the as-synthesized nanorods/nanoparticles TiO2, indicating the rods-like morphology. In addition, it’s TEM image clearly showed not only nanorods but also nanoparticles. The nanorods in the composite powder had diameter about 10-20 nm and the lengths of 100-200 nm, the nanoparticles had diameter about 5-10 nm. The electron diffraction pattern supported that the nanorods/nanoparticles composite was anatase-type TiO2. The lattice fringes of the nanorods and the nanoparticles appearing in the image (d = 0.35 nm) also allowed for the identification of the anatase phase. HRTEM images of nanorods/nanoparticles with clear lattice fringes, again confirming its high crystallinity. The prepared material had average pore diameter about 7-12 nm. The BET surface area and pore volume of the sample are about 203 m2/g and 0.655 cm3/g, respectively. The nanorods/nanoparticles TiO2 with mesoporous structure showed higher photocatalytic activity (I3- concentration) than the nanorods TiO2, nanofibers TiO2, mesoporous TiO2, and commercial TiO2 (ST-01, P-25, JRC-01, and JRC-03). The solar energy conversion efficiency (h) of the dye-sensitized solar cell using nanorods/nanoparticles TiO2 with mesoporous structure was about 7.12 % with Jsc of 13.97 mA/cm2, Voc of 0.73 V and ff of 0.70; while h of the cell using P-25 reached 5.82 % with Jsc of 12.74 mA/cm2, Voc of 0.704 V and ff of 0.649.
9:00 PM - E9.40
Heterocyclic Ssystems as Mercury(II) Selective Ionophores.
Rakesh Mahajan 1 , Pallavi Sood 1 , Mohinder Mahajan 1 , Alka Marwaha 1
1 Chemistry, Guru Nanak Dev University, Amritsar, Punjab, India
Show Abstract9:00 PM - E9.42
One Step Preparation of Ultra-wide β-Ga2O3 Nano & Microbelts and their Luminescence Study.
Aurangzeb Khan 1 , Wojciech Jadwisienczak 2 , Martin Kordesch 1
1 Physics & Astronomy and CMSS Program, Ohio University, Athens, Ohio, United States, 2 School of Electrical Engineering and Computer Science, Ohio University, Athens, Ohio, United States
Show Abstract9:00 PM - E9.43
Connected Electrodes by the Growth of Germanium Dioxide Nanowires
Chun-I Wu 1 , Timothy Hogan 1
1 Dept. of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan, United States
Show AbstractGermanium dioxide nanowires have gained significant interest lately in part this is due to the bandgap of 2.44 eV, and high index of refraction, n=1.63. In this paper we aim at investigating the lateral growth of high density metal-catalyzed germanium dioxide nanowires between pairs of electrodes with various microns separation. Different materials were used as electrodes. After the catalytic metal was placed on the electrodes surfaces, a thermal annealing process was initiated to grow nanowires and to eventually form ‘nanobridges’. Nanobridges have certain unique properties, such as a high surface-to-volume ratio and the capability of connecting two electrodes, which allow them to be effectively used as nanosensors. The products are characterized by scanning electron microscopy (SEM), as well as X-Ray diffraction (XRD).
9:00 PM - E9.45
Active-Site Imaging for Au Catalyst Nanoparticles on rutile-TiO2 with TEM techniques.
Takayuki Tanaka 1 2 , Masafumi Ando 1 , Kunio Takayanagi 1 2
1 Department of Condensed Matter Physics, Tokyo Institute of Technology, Meguro, Tokyo, Japan, 2 , CREST, JST Japan
Show AbstractRecently atomic-resolution images of catalyst nanoparticles in gas environments (~100 Pa) are observed by in-situ transmission electron microscope (in-situ TEM) [1]. Further developments of novel techniques including aberration- corrected TEM and electron energy loss spectroscopy (EELS) will realize direct observation of adsorbed molecules and analysis of localized electron states before long. Compactly designed TEM-Gas Inlet Holder is necessary for receiving benefits of novel TEM technologies.We developed a TEM-Gas Inlet Holder (Kitano Seiki, KTEM-K400) equipped with a gas cylinder, a gas inlet tube, a specimen room exposed to gas environments, and pumping paths for differential evacuation, and apertures for TEM observation, based on design of a standard side entry holder.We demonstrate dynamic behaviors in CO oxidation of Au / TiO2 catalysts. Gold nanoparticles deposited on TiO2 exhibit high catalytic activity of CO oxidation, in contrast to very low catalytic activity of bulk gold [2]. The activity was explained from the structure of Au particles and interface between Au particle and supports. We discuss changes of shape and size of Au nanoparticles exposed to CO and O2 gases in relation to Au catalyst activity.[1] PL Hansen, et al, Science 295 (2002) 2053. [2] M Haruta, et al, J. Catal. 144 (1993) 175.
9:00 PM - E9.5
Silica Nanofiber Mats containing Metal Oxide Crystals via Coaxial Electrospinning and Sol-gel Synthesis.
Jeanne Panels 1 , Yong Joo 1
1 Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, United States
Show AbstractOne dimensional, inorganic, nanosized fiber mats are of interest for their high thermal stability and large surface to mass ratios. Recently, we have developed sub-micron scale vanadia/silica nanofiber mats by electrospinning silica sol-gel precursor containing vanadium oxytriisopropoxide (VOTIP), followed by calcinations at high temperature. Although the presence of uniformly dispersed orthorhombic V2O5 crystals in silica nanofibers have been identified by X-ray diffraction (XRD) and Energy Filtering Transmission Electron Microscopy (EFTEM) studies, X-ray photoelectron spectroscopy (XPS) experiments reveal that only about one half of the vanadium resides on the fiber surface. V2O5 crystal particles must be on the silica fiber surface to utilize their ability to detect trace amounts of toxic or flammable gases, including ammonia and hydrocarbons. In the current study, coaxial electrospinning is used to increase vanadium oxide loading on the surface of the fibers. Three different approaches have been implemented in coaxial electrospinning of silica and vanadia systems. First, sol-gel synthesis is used to obtain an inner jet containing pure silica precursor and an outer jet containing silica and vanadium oxide precursors. Secondly, the inner jet contains only vanadium oxide precursor, while sol-gel synthesis is used to obtain an outer jet containing silica precursor. Silica is removed to obtain pure V2O5 fibers. Lastly, sol-gel synthesis is used to obtain an inner jet containing silica precursor and an outer jet containing vanadium oxide precursor with a polymer binder such as polyvinyl acetate. After calcination the polymer is removed leaving only V2O5 crystals on the surface of the silica fibers. Dispersing V2O5 nanoparticles onto the surface of silica nanofibers can allow outstanding specificity and selectivity in gas sensing to be gained because nanofiber mats can provide a highly porous template where the gas can flow through it and thereby effectively utilize the entire active sites of metal oxide crystals on the surface of fibers. SEM images show the coaxially electrospun inorganic fibers are sub-micron in diameter and their morphology is maintained after calcination. Various properties of coaxially electrospun fibers obtained from physisorption experiments, XPS, XRD and EFTEM studies together with their gas sensing characteristics via measuring the variation in the resistance and absorbance will be presented. Finally, coaxial electrospinning will be utilized to include other metal oxides on the fiber surface such as TiO2, Fe2O3, and SnO2.
9:00 PM - E9.6
Investigation Based on FTIR Analysis of the Gas Detection Mechanism in Metal Oxide Chemical Sensors.
Marie-Isabelle Baraton 1 , Lhadi Merhari 2
1 UMR CNRS 6638, University of Limoges, Limoges France, 2 , CERAMEC R&D, Limoges France
Show AbstractIn an attempt to bridge the gap between the “atomistic model” and the “rigid band model”, we focus on two complementary approaches of Fourier transform infrared (FTIR) spectroscopic analysis of metal oxide semiconductors. Firstly, we describe the chemical reactions occurring at the surface of semiconductor nanoparticles when a reducing or oxidizing gas is adsorbed. These surface reactions are at the origin of the gas detection by chemical gas sensors based on layers of metal oxide nanoparticles. Through successive gas adsorption/desorption sequences, reversible and irreversible reactions can be identified. The irreversible reactions leading to the formation of new species, definitely poisoning surface reactive sites, may be responsible for a drift of the sensor response. Then, based on the Drude theory and Harrick’s experimental work, we show how FTIR spectroscopy can be used to monitor the variations of the free carrier concentration versus gas adsorption in semiconductors. Indeed, free carriers absorb in the infrared and microwave ranges and their absorption is a linear function of λα (λ being the wavelength and α being generally equal to 2). From the variations of the infrared absorbance, free carrier and conductivity can be deduced.Finally, to correlate surface chemistry with electronic properties, we describe our approach combining both possibilities offered by FTIR spectroscopy. This approach allows us to clarify the fundamentals of the gas detection mechanisms and to obtain an unequivocal and rapid correlation between the electrical response of the chemical sensors and the infrared absorption of sensing metal oxide semiconductor nanoparticles.
9:00 PM - E9.7
Rapid Label-free Protein Detection Arrays on Coated Silicon Wafers.
Christopher Striemer 2 1 , Charles Mace 3 , Benjamin Miller 3 4 5
2 , Pathologics, LLC, Rochester, New York, United States, 1 Electrical and Computer Engineering, University of Rochester, Rochester, New York, United States, 3 Biochemistry and Biophysics, University of Rochester, Rochester, New York, United States, 4 Dermatology, University of Rochester, Rochester, New York, United States, 5 The Center for Future Health, University of Rochester, Rochester, New York, United States
Show Abstract9:00 PM - E9.8
Polydiacetylenes as Hydrogen Bonded Strain Sensors via Raman Spectroscopy
Jennifer Kauffman 1 , Tony Neely 3 , William Pennington 2 , Timothy Hanks 3 , Michael Ellison 1
1 School of Materials Science & Engineering, Clemson University, Clemson, South Carolina, United States, 3 Department of Chemistry, Furman University, Greenville, South Carolina, United States, 2 Department of Chemistry, Clemson University, Clemson, South Carolina, United States
Show AbstractPolydiacetylene (PDA) polymers exhibit a chromatic response to solvents, temperature and mechanical stress. When polymerized through a solid state reaction, the polymer backbone is planar with an all trans conformation of the side chains. With the entire polymer backbone in the same plane, extended, continuous π overlap is observed. When the PDA backbone is distorted by an outside force, the extended conjugation is interrupted. This phenomenon can be measured quantitatively by the strong Raman peaks exhibited by the PDA. In-situ strain measurements can be obtained by examining the Raman scattering of PDA’s that have been incorporated at very low concentration into a host polymer. The Raman spectra show nearly linear shifts in frequency corresponding to the strain in the matrix polymer. The PDA synthetic route allows considerable freedom to modify the side chains of the probe increasing its compatibility with a variety of matrix polymers. When the probe has side chain functional groups complementary to those of the host matrix, hydrogen bonding may be used to integrate the PDA’s into the host polymer. The resulting polymer blends are solution cast into thin films and subjected to simultaneous tensile testing and Raman analysis. A linear relationship has been determined between the Raman wavenumber shift and the strain induced in the host matrix. Three systems have been examined to determine the effectiveness of the sensor: a polyurethane synthesized from MDI and ethylene glycol hydrogen bonded to 4-BCMU PDA; a polyurethane-polydiacetylene copolymer made from dodeca-5,7-diyne-1,12-diol, MDI, and ethylene glycol; and finally a medical grade polyurethane, Tecoflex, hydrogen bonded to 4-BCMU PDA.
9:00 PM - E9.9
Electrospun Polyaniline- Urease Biocomposite as Urea Biosensor
Smita Gadre 1 , Aisha Bishop 1 , Perena Gouma 1
1 Materials Science and Engineering, SUNY at Stony Brook, Stony Brook, New York, United States
Show AbstractUrease maintains its activity in electrospun fibers of PVP. PANI/PVP electrospun composites have shown p-type semiconducting behavior in presence of ammonia. This work discusses composite made of PVP and PANI for immobilization of urease. PANI was dispersed in PVP solution in different concentration. Immobilization of urease was achieved by electrospinning Urease/PVP/PANI solution. These electrospun can be used as urea sensor. Urease catalyzes hydrolysis of urea releasing NH3, which can be sensed by PANI/PVP matrix. Transmission Electron Microscopy studies were performed to on the PVP/PANI/urease matrix to access its microstructure. Results from gas sensing, electrochemical analysis, and TEM characterization will be discussed.
Symposium Organizers
Anis Zribi GE Global Research Center
Changming Li Nanyang Technical University
Larry Nagahara Motorola Labs
Magnus Willander Goeteborg University
E10: Hierarchal Self Assembly for Biological and Chemical Detection
Session Chairs
Bengt Kasemo
Changming Li
Thursday AM, November 30, 2006
Room 210 (Hynes)
9:00 AM - **E10.1
Self-Assembled Functional Nanostructures with Electrochemistry.
Erkang Wang 1
1 State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Changchun, Jilin, China
Show AbstractWe shall present the progress of the synthesis, nanostructure-assembly, function and electrochemical applications of nanomaterials in this laboratory. Different methods for preparation of nanomaterials were proposed particularly, focused on gold nanoparticles. Also , large scale of polymer nanobelt and nanoplate were fabricated by simple route. 2D, 3D and supermolecular can be assembled on ITO and GC-supported gold nanoparticle surfaces forming nanostructurse as nanoelectrode arrays. Electrochemistry of nanostructure assemblies of monolayer, bilayer and multilayer at electrodes showing special characteristics caused by the size, surface and curvature of nanoparticles was found. The results of the UPD–induced interfacial atomic rearrangment of gold surface from rough to atomic flat indicating that electrochemical methods have potential for microprocessing.
9:45 AM - E10.3
Spatially Controlled Materials Biotemplating Using Nanoscale Patterning of Genetically Modified Viruses
Asher Sinensky 1 , Angela Belcher 1 2
1 Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractUsing phage display, we have previously demonstrated the tremendously varied ability of the M13 bacteriophage to biotemplate many different materials using genetically induced peptide fusions on the viral surface. This biotemplating is most useful when it can be combined with self-assembly and/or directed assembly in order to build structures and devices. In this work, we present a generalizable approach for covalently binding genetically modified viruses to dip-pen patterned surface features and subsequently using the genetic modification to direct the assembly of inorganic materials. Dip-pen nanolithography is used to chemically pattern a substrate. The chemical patterning is then activated such that it will spontaneously cross-link with viruses in solution. Once bound, the genetic functionality of the virus can be exploited to direct the patterning of inorganic materials.
10:00 AM - E10.4
Soft Lithographic Patterning of Functional Lipid Vesicles and inside microfluidic channels using Well-Oriented NanoWell Array Metrics for Integrated Digital Nanobiosensors
HeaYeon Lee 1 2 , BongKuk Lee 1 2 , PilNam Kim 3 , KahpYang Suh 3 , Tomoji Kawai 1 2
1 ISIR-SANKEN, Osaka university , Osaka Japan, 2 Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation (JST), Saitama Japan, 3 School of Mechanical and Aerospace Engineering, Seoul National University, Seoul Korea (the Republic of)
Show AbstractRecently, a new paradigm of nanobiosensors combining miniaturization and integration has been exploited in areas such as combinational chemistry, biotechnology, functional genomics, proteomics and clinical diagnostics. The notion of automation, miniaturization and integration requires the fabrication of appropriately designed nanometrics for high sensitivity homogenous assays. And also lipid-membrane vesicles membranes have attracted considerable attention as a biomimetic platform for various applications such as fundamental biological research of cell-membranes, lipid-assisted bioassays and biosensors. In this paper, we present the nanometrics geometry of a well-oriented nanowell (ONW) array derived from nanofabrication technology which can easily be employed for digital detection with a high S/N ratio, miniaturization, integrated assays and single molecule analysis. In this geometry, most of the area of the Au electrode was covered with the blocking layer, and only a nanosized gold surface becomes exposed to the open space above the ONW. We also present soft lithographic patterning of functional lipid-membrane vesicle onto ONWs array substrates and inside microfluidic channels. Nano/microcontact printing and capillary moulding methods were used to create robust microstructures of the polyethylene glycol (PEG)-based polymers, which acted as resistant layers against non-specific adhesion of lipid vesicles. Nano/Micropatterns of PEG-based polymers were used as a template to resist nonspecific adsorption of lipid bilayer vesicles. Both methods could be used to fabricate the patterned PEG surfaces with the substrate surface clearly exposed whereas the capillary moulding approach turned out to be more efficient in regulating the adhesion and migration of the lipid vesicles. The patterned PEG surfaces resisted nonspecific adsorption of lipid vesicles allowing for adsorption of the lipid bilayers on the exposed regions of two dimensional surfaces and inside microfluidic channels in comparison to glass control. We believe these findings can be related to various liposome applications such as drug delivery system, electrochemical or biosensors and nano scale membrane function studies.References1. P.N.Kim, S.E.Lee, H.S.Jung, H. Y.Lee, T.Kawai, and K.Y. Suh. Lab on a chip, 6, (2006) 54-59. 2. H.Y. Lee, J.W. Park, J.M.Kim, H.S.Jung, T. Kawai, Appl. Phys. Lett. To be accepted (2006).3. J.M. Kim, H.S. Jung, J.W. Park, H.Oka, T.Yukimasa, H.Y. Lee, T.Kawai, J. Am. Chem. Soc.(Article) , 127 (2005) 2358-23624. H.S. Jung, J.M. Kim, J.W. Park, H.Y. Lee, T.Kawai, Langmuir (Article), 21(13) (2005) 6025-6029.
10:15 AM - E10.5
Creation of Integrated Platforms for Engineered Cell-Cell Communication via Cell-Directed Assembly
Eric Carnes 1 , Carlee Ashley 1 , DeAnna Lopez 1 , Cynthia Douthit 1 , Jennifer Pelowitz 1 , Shelly Karlin 1 , Adam Wise 3 , Seema Singh 2 , C. Brinker 1 2
1 Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico, United States, 3 , Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Self-Assembled Materials Department, Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractImmobilization of individual cells and collections of cells in well-defined, reproducible, nano-to-microscale structures that allow structural and functional manipulation and interrogation is important for developing new classes of biotic/abiotic materials, for elucidating responses of cell-cell communication pertaining to disease, injury/stress, or therapy, and for constructing functional cell-based sensors. Although there has been considerable recent progress in investigating the response of cells to chemical or topological patterns defined lithographically on 2D surfaces, it is necessary to advance from two-dimensional adhesion on surfaces to three-dimensional architectures that better represent the nanoporous, 3D extracellular matrix (ECM). 3D immobilization in nanostructured hosts enables cells to be surrounded by other cells, maintains fluidic connectivity and accessibility, and allows development of 3D molecular or chemical gradients that provide an instructive background to guide cellular behavior. Although 3D cell immobilization in polymers, hydrogels, and inorganic gels has been practiced for decades, these approaches do not provide for bio/nano interfaces with 3D spatial control of topology and composition important to both the maintenance of natural cellular behavior patterns and the development of new non-native behaviors and functions. Utilizing our recent discovery of a living cell’s unique ability to organize nanocomponents and extended nanostructures, thereby creating functional bio/nano interfaces, we have developed a means by which we can manipulate the extracellular environment thereby allowing immobilized cells to retain normal functionality while providing a route for in-situ behavior modification.Using our printing and patterning techniques developed for inorganic nanostructures, we are able integrate cells into platforms needed for electronic, optical, and spectroscopic interrogation. With this ‘cell-directed assembly’ approach, we are able to create new classes of nominally solid-state materials and devices displaying a symbiotic relationship between the biotic and abiotic components. For example, we present the development of a platform for studying cell-cell communication with precise control of cell density and spacing allowing the development and interrogation of cell-to-cell communication networks associated with quorum sensing, biofilm formation, and many physiological events in pathogenic bacterial infections. In addition to spatial control of cells and the corresponding effects on communication, we also demonstrate the integration of non-native components to increase functionality of the system, such as nanocrystals for SERS-based sensing and DNA plasmids for patternable, in-situ genetic modification.
10:30 AM - E10.6
Manipulation of Neuron-neuron Interactions with 3D Substrates.
Sophie Pautot 1 , Ehud Isacoff 1
1 MCB, UC Berkeley, Berkeley, California, United States
Show Abstract10:45 AM - E10.7
Layer by Layer Assembly of Outer Membranes for Enhanced Sensitivity and Extended Linearity in an Implantable Amperometric Glucose Sensor.
Santhisagar Vaddiraju 1 , Ritesh Tipnis 1 , Vincent Ustach 1 , Faquir Jain 2 , Diane Burgess 3 , Fotios Papadimitrakopoulos 1 4
1 Nanomaterials Optoelectronics Laboratory, Polmer Program, Institute of Material Science, University of Connecticut, Storrs, Connecticut, United States, 2 Nanomaterials Optoelectronics Laboratory, Electrical and Computer Engineering, University of Connecticut, Storrs, Connecticut, United States, 3 Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut, United States, 4 Department of Chemistry, University of Connecticut, Storrs, Connecticut, United States
Show Abstract11:30 AM - **E10.8
Supercritical Hydrothermal Synthesis of Organic-inorganic Hybrid Nanocrystals, Perfect Dispersion and Self-assembly.
Tadafumi Adschiri 1
1 , IMRAM, Tohoku University , Sendai Japan
Show AbstractWe propose a new method to synthesize organic-inorganic hybrid nano-crystals by supercritical hydrothermal synthesis. At supercritical conditions, water and organic species forms a homogeneous phase, and unique organic-inorganic reactions occur without a catalyst. Thus, by introducing organic species (aminoacids, carboxylic acids, amines, alcohols, aldehydes, amino acids etc.) during supercritical hydrothermal synthesis, nanoparticles whose surface was chemically bonded with organic molecules were synthesized. Particle size was in the range from several nm. By selecting a proper organic modifier, crystal shape can be controlled to be sphere, nano-cube, nano-ribbon etc. Organic modified nano crystals could be perfectly dispersed in organic solvents or in aqueous solutions. After the drying of this colloid, we obtained self-assembly structure of nanocrystals. This implies a variety of applications of the nanoparticels including nanohybrid polymers, nano-ink, and nano-paints.
12:00 PM - E10.9
DNA-Gold Nanoparticle Scaffold for Three-Dimensional Periodic Nanoassemblies
Weian Zhao 1 2 , Yingfu Li 2 1 , Michael Brook 1 , Yan Gao 1 , Srinivas Kandadai 2
1 Chemistry, McMaster University, Hamilton , Ontario, Canada, 2 Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
Show Abstract12:15 PM - E10.10
Protein Assembly Through Site-specific Interactions with Gold Nanoparticles.
Minghui Hu 1 , Luping Qian 1 , Raymond Brinas 1 , Elena Lymar 1 , James Hainfeld 1
1 Biology Department, Brookhaven National Laboratory, Upton, New York, United States
Show Abstract12:30 PM - E10.11
Nanopatterning of Poly Ethylene Glycol-Self Assembled Monolayer by Combining Nanoimprint Lithography and Lift-Off Method
Bong-Kuk Lee 1 2 , Hea-Yeon Lee 1 2 , Tomoji Kawai 1 2
1 ISIR-SANKEN, Osaka university , Osaka Japan, 2 Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama Japan
Show AbstractThe patterning of biomolecules such as DNA, protein, and cells onto the micro/nanosize solid support of the micro/nanosize was interested in the development of small biosensors benefiting from well defined active areas, increased control over the density of receptor elements, and controlled reactivity of the receptor elements. The universal patterning techniques for producing submicrometer patterns are microcontact printing, “controlled” colloidal lithography, x-ray interference lithography, and nanoimprint lithography (NIL). A critical point for the development of biomimetic nanopatterning is avoided the nonspecific absorption among biomolecules onto surface. The nonspecific absorption of biomolecules on surface will most likely affect the accuracy and sensitivity of bioassay. Therefore it was required the non-interactive areas of the pattern through designed chemical surface in order to ensure a very low background signal. Polyethyleneglycol (PEG) molecules have been used extensively as a biocompatible material because of their low toxicity, low immunogenicity, and the ability to prevent nonspecific protein adsorption and cell adhesion. The molecule was occurred steric repulsion, large PEG exclusion volume, rapid mobility of highly hydrated PEG chains, low PEG-water interfacial energy, and weak PEG-protein binding interactions. In order to the fabrication of the nanopatterns of PEG-Self Assembled Monolayer (SAM) on gold surface, we used the top-down and bottom-up nanotechnology approach through NIL and the molecular assembly patterning by lift-off. The gold layer (100 nm) and Ti sublayer (5 nm) had been fabricated on the silicon wafers by a sputtering technique. This substrate was then spin-coated with a thin film of 110 nm of poly(methyl methacrylate) (PMMA), followed by a soft baking for 5 min at 150 °C. A mold coated with an anti-adhesive layer is imprinted into a heated PMMA film followed by an Ar dry etching step that converts the topography into a PMMA/Au contrast. A biotin-PEG-disulfide dissolved in ethanol was spontaneously conformed SAM on gold surfaces. After PMMA lift-off with an acetone, the exposed gold surface was backfilled with protein-resistant methyl-PEG-thiol to form a nonfouling surface. Finally, the substrate was dipped into a buffered solution (10 mM PSB, pH 7.4) with fluorescently labeled streptavidin and rinsed with same buffer. The stepwise fabrication of protein nanopatterns by using functionalized PEG thiolates SAMs was characterized at each process step in order to ensure well defined chemical surface and pattern geometry. This novel process is a flat nanopatterning technology which is fast, reproducible, and economical method because the PEG can be functionalized with a variety of bioactive groups and allows a great flexibility on chemical modified surface.
12:45 PM - E10.12
Directed Assembly of Nanobeads Using Alumina and Titania Templates: Applications in Nanomanufacturing and Nanomedicine.
Evin Gultepe 1 2 , Dattatri Nagesha 1 2 , Latika Menon 1 2 , Srinivas Sridhar 1 2
1 Physics, Northeastern University, Boston, Massachusetts, United States, 2 Electronics Material Research Institutue, Northeastern University, Boston, Massachusetts, United States
Show AbstractNanoporous alumina templates have been extensively used for the fabrication of various types of nanoscale electronic, opto-electronic and magnetic devices and as templates to form nanoarrays. Anodization of aluminum in an acid bath under controlled conditions results in the formation of anodic porous alumina with controlled pore diameter, interpore separation and uniform periodicity. Anodization parameters have been optimized to fabricate ordered arrays with pore diameter of 10-250 nm, pore separation of 30-450 nm, thickness of few nm to microns and pore density in the order of 1010-1015 pores/cm2 over large areas. In a novel nanofabrication approach, we have used these alumina nanohole arrays as a template for assembly of nanobeads with implications in high-rate nanomanufacturing. Polystyrene latex beads of uniform size were assembled within the alumina nanohole arrays by electrophoresis. This method results in the uniform, periodic assembly of nanoelements over large surface areas in a very short time which is a very important criterion in nanomanufacturing. Similarly, nanoporous alumina templates can be used as a template to assemble carbon nanotubes for use in CNT-based electronics. Titania nanotemplates can be fabricated in a similar manner by the controlled anodization of titanium. Since titania is biocompatible, nanoporous titania can be introduced as a coating on the surface of biomedical implants for localized delivery of various therapeutic agents such as antibiotics, antimicrobials, anti-inflammatory agents and growth factors. Titania nanoarrays could also be filled with polymeric nanoparticles loaded with drugs and used for local drug delivery applications. Results from these experiments will be presented. Work supported by National Science Foundation through NSF-0504331 IGERT Nanomedicine Science and Technology.
E11: Microfluidics/Preconcentrator for Biological and Chemical Detection
Session Chairs
Thursday PM, November 30, 2006
Room 210 (Hynes)
2:30 PM - **E11.1
Integrating Micro/Nanofluidics with Thermal Sensing and Control.
Qiao Lin 1
1 Mechanical Engineering Department, Columbia University, New York, New York, United States
Show AbstractThermal effects are ubiquitous to biological processes. Microelectromechanical systems (MEMS) technology can be used to fabricate devices for fast and sensitive thermal sensing and control. When integrated with micro/nanofluidic systems, such MEMS thermal devices allow interrogation of biomolecules in controlled micro/nano environments unattainable with conventional technologies. We demonstrate the promise of such an integration approach to enable innovative biomolecular manipulation and detection.Microfluidic systems can be functionalized with surface-attached, thermally responsive micro- and nanoscale polymer films for intelligent biomolecular manipulation. A thermally responsive polymer undergoes a temperature-induced phase transition in aqueous solution. As the temperature increases above the polymer’s lower critical solution temperature (LCST), the polymer film changes from a swollen, hydrophilic state to a collapsed, hydrophobic state. The thermally responsive polymers poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and poly(N-isopropylacrylamide) (PNIPAAm) are synthesized via atom transfer radical polymerization. Their temperature-dependent swelling is studied using atomic force microscopy. Thermally induced changes in their wettability and protein adsorption behavior are investigated using a MEMS device, whose backside is integrated with heaters and temperature sensors, and whose frontside is a smooth flat surface suitable for polymer coating. Also using integrated MEMS heaters, a microfluidic device is constructed whose surfaces are functionalized with the thermally responsive polymers. The device can potentially enable intelligent preconcentration and separation of biomolecules, which adsorb to or desorb from the polymer surfaces under thermal control.Integration of thermal sensing with microfluidics can enable measurement of thermodynamic properties of biomolecules. We have developed a miniaturized differential scanning calorimeter (DSC) featuring integrated polymeric thermal and microfluidic components. The device consists of two microfluidic chambers, each containing a freestanding polymeric membrane on which MEMS heaters and temperature sensors are integrated. During measurement, one chamber is filled with a biomolecular sample and the other a reference buffer. As the sample and buffer temperatures are varied, the small differential temperature between the sample and buffer is measured to assess biomolecular conformational changes. The device demonstrates a capability to measure nanowatt-scale biological thermal power in orders-of-magnitude smaller sample volumes when compared with conventional instruments. Successful detection of protein unfolding suggests that the device has potential applications to biomolecular binding studies and label-free screening of drug leads.
3:00 PM - E11.2
Biomolecular Motors – The Natural Way of Active Transport in Nanofluidic Devices.
Thorsten Fischer 1 , Ashutosh Agarwal 1 , Parag Katira 1 , Isaac Luria 1 , Henry Hess 1
1 Materials Science & Engineering, University of Florida, Gainesville, Florida, United States
Show Abstract3:15 PM - E11.3
Fabrication of Open Tubular Gas Chromatography Columns and MEMS-based Preconcentrators by the Layer-by-layer Assembly Process.
Vaibhav Jain 1 , Randy Heflin 2 , Masoud Agah 3 , Larry Taylor 4 , Mehdi Ashraf-Khorassani 4 , Bassam Alfeeli 3 , Syed Ali 3
1 Macromolecular Science and Engineering, Virginia Tech, Blacksburg, Virginia, United States, 2 Physics, Virginia Tech, Blacksburg, Virginia, United States, 3 Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia, United States, 4 Chemistry, Virginia Tech, Blacksburg, Virginia, United States
Show AbstractThe layer-by-layer (LBL) assembly technique for adsorption of nanoscale layers of alternating electric charge has been used to form the stationary phase of open tube fused silica columns and coat embedded walls of MEMS-based preconcentrators for micro gas chromatography (GC). The thickness of the homogenous polymer and nanoparticle coatings ranges from 10-500 nm, and it can be easily controlled in the range of 0.3 to >10 nm per bilayer by varying the pH and salt concentration of polyelectrolyte solutions. The LBL technique also allows manufacturing ease and low cost. The crosslinking agent, EDC (1-Ethyl-3-[3- dimethyl amino propyl] carbodiimide Hydrochloride) and stabilizer, NHS (N-hydroxysuccinimide) have been employed to crosslink the carboxylic acid group and the primary amine to form high temperature (200-250C) stable carboimide layers. The chemical properties of LBL films are tailored to enhance the separation resolution of complex gaseous mixtures. Ina ddition, coating the embedded walls of a MEMS preconcentrator with layers of silica (45 nm) and gold (20 nm) nanoparticles provides a large surface area for interaction with and trapping of gas molecules. The reduction in the overall mass of the structure allows rapid thermal desorption to generate narrow bands for injection into GC columns. The preconcentrator is fabricated using a silicon-on-glass process and has on-chip thermal control through integrated heaters and temperature sensors on the backside of the silicon wafer. This minimizes system integration difficulties and, significantly, reduces the dead volume of the system and band broadening of the injected plug in the transfer lines. It also aids in reducing the separation speed by 3-4 × making the separation of both n-alkanes from C5-C16 and polyaromatic hydrocarbons that vary in ring-size possible in less than 60 s.
3:30 PM - E11.4
Microfluidic Electroporation for Analysis of Intracellular Materials at Single Cell Level.
Chang Lu 1 2 , Hsiang-Yu Wang 2
1 Agricultural and Biological Engineering, Purdue University, West Lafayette, Indiana, United States, 2 Chemical Engineering, Purdue University, West Lafayette, Indiana, United States
Show AbstractElectroporation has been widely used to load impermeant exogenous molecules into cells. Rapid electrical lysis based on electroporation has also been applied to analyze intracellular materials at single cell level. There has been increasing demand to implement electroporation in a microfluidic format as a basic tool for applications ranging from screening of drugs and genes to studies of intracellular dynamics. In this report, we have developed a simple technique to electroporate mammalian cells with high throughput on a microfluidic platform. In our design, electroporation only happened in a defined section of a microfluidic channel due to the local field amplification by geometric variation. The time of exposure of the cells to this high field was determined by the velocity of the cells and the length of the section. We determined that electroporation of Chinese hamster ovary (CHO) cells occurred when the local field strength was increased to around 400 V/cm. The internalization of membrane-impermeant molecules (SYTOX green) with cell viability preserved was also carried out to demonstrate transient electropermeabilization. The influence of the operational parameters of the device on cell viability was determined. We also studied rapid cell lysis when the field intensity was in the range of 600-1200 V/cm. The rupture of cell membrane happened within 30 ms when the field strength was 1200 V/cm. Based on the results, we designed a simple microfluidic device which carries out chemical analysis of single cells at a maximum rate of 75-85 cells/min operated with a single DC power supply and a syringe pump. The fields for electrical lysis of cells and electrophoresis of intracellular materials are designed to have different intensities, determined by the local geometry of the channel. The device was demonstrated using the Chinese Hamster Ovary (CHO) cells that loaded with Calcein AM. The lysate from single cells was injected in the separation channel and detected downstream from the lysis intersection. Our device has the potential for carrying out studies related to single cell proteomics.References1. Wang, H.Y. and Lu, C. Electroporation of mammalian cells in a microfluidic channel with geometric variation. Anal Chem (2006) in press.2. Wang, H.Y. and Lu, C. Microfluidic chemical cytometry based on modulation of local field strength. Chem Commun submitted.
3:45 PM - E11.5
An Electrohydrodynamic Micropump for on-Chip Micro Bioreactors.
Chia-Ling Chen 1 2 , Azadeh Khanicheh 3 , Selvapraba Selvarasah 1 2 , Constantinos Mavroidis 3 , Mehmet Dokmeci 1 2
1 Electrical and Computer Engineering , Northeastern University, Boston, Massachusetts, United States, 2 NSF Center for High-rate Nanomanufacturing (CHN), Northeastern University, Boston, Massachusetts, United States, 3 Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts, United States
Show AbstractMicrofluidics devices based on Microelectromechanical systems (MEMS) technology have been attracting significant interest due to their immense potential that allows one to create miniature tools for life sciences. Despite the resources spent on micropumps, still there is a need for a low power, simple, inexpensive micropump that fulfills the demands for on-chip fluid pumping. The applications of this technology are vast, some include but are not limited to biotechnology, cell biology and tissue engineering. Even though discovered in 60’s, on chip applications of electrohydrodynamic (EHD) pumping has not been fully explored at the macro scale mainly due to large voltages required to operate it. By applying MEMS technology, the supply voltage can be reduced with values acceptable for many commercial applications. The availability of high aspect ratio epoxy based-photoresist (ie SU-8), has allowed one to explore micro reactor applications using EHD pumping for on-chip applications. We have designed, fabricated and tested a simple, low power, ultra miniature (2.3mm3) EHD based micropump (with no moving parts) for life sciences applications using a thick(80μm tall) SU8 photoresist. The pumping fluid was 2-(2-butoxyethoxy) ethyl acetate (referred to as BCRA) dielectric fluid, which has a relatively good dielectric constant (k~ 7.7) and a relatively high viscosity (η~ 3.1 mPa.s) hence, the liquid inside the small channels preferentially travel along the sidewalls during pumping. We observed pumping for voltages as low as 50 Volts while sinking 0.1μA of current. Further tests are underway to further quantify pumping parameters. The full paper will describe the details of fabricating these micropumps to be used for Micro Bioreactors, and additional testing results.
4:30 PM - E11.6
Fabrication of Porous Nanostructured Thin Films For Microfluidic and Microassay Applications.
Louis Bezuidenhout 1 , Gregory Kiema 2 , Martin Jensen 1 , Michael Brett 1
1 Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, 2 Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
Show AbstractThe functionality of microfluidic and microassay devices could be enhanced through further development of porous engineered microstructures. Here, new structural elements have been developed for these devices, fabricated with porous nanostructured thin films deposited by the glancing angle deposition (GLAD) technique. With the GLAD technique, engineered structures such as vertical posts, slanted posts, helices, and square spirals can be directly grown inside microfluidic channels. A high surface area channel (517cm2/cm2) was made by depositing a silicon oxide porous film in glass microchannels (up to 4.5μm deep and 50μm wide). Similar channels were also fabricated by patterning channels in a photoresist-coated porous film. Devices with channels containing periodic arrays of Si pillars with controllable porosity and architecture were fabricated with only one lithography and deposition cycle. The entire device was made by depositing a single GLAD porous film with areas of different porosity defining the channels. The channels, 200μm wide and 10.5μm deep, contained helical pillars with pore sizes ranging from 100nm-2μm, while a more dense nanofibrous helical film made up the remainder of the device. Fluid flow activated by negative pressure was demonstrated in this device, using both a dye solution and a 50nm microsphere solution. Self-sealed microchambers and channels were made by growing a SiO2 porous film on 14μm high silicon mesas (2.5x2.5μm, 7x7μm, and 25x25μm) and lines (2.5 to 50μm wide). Material selection is not limited to silicon or silicon oxide, but may include a wide range of semiconductors, insulators and metals. New developments utilizing GLAD porous films will also be presented. The reported elements are suitable for a range of applications, including – but not limited to – chromatography, nano-assays and capillary electrophoresis.
4:45 PM - **E11.7
Fluid Breadboard Architecture and Demonstration of High Sensitivity Protein Detection
Chang Liu 1
1 Micro and Nanotechnology Lab, University of Illinois, Urbana, Illinois, United States
Show Abstract5:15 PM - E11.8
Integrated Nanoscale Silicon Membranes for Separation, Collection, and Preconcentration of Biomolecules.
Christopher Striemer 1 , Thomas Gaborski 2 , Jessica Snyder 3 , David Fang 1 , James McGrath 2 , Philippe Fauchet 1
1 Electrical and Computer Engineering, University of Rochester, Rochester, New York, United States, 2 Biomedical Engineering, University of Rochester, Rochester, New York, United States, 3 Biochemistry and Biophysics, University of Rochester, Rochester, New York, United States
Show Abstract5:30 PM - E11.9
New Sol-Gel Functionnalized Mesoporous Material for Nitroaromatics Detection.
Xavier Le Guevel 1 , Adeline Bardet 1 , Heloise Delvaux 1 , Frédéric Parret 1 , Laurence Beaurain 1 , Nathalie Eloy 1 , Pierre Montmeat 1 , Lionel Hairault 1 , Philippe Belleville 1 , Philippe Prene 1
1 , CEA Le Ripault, Monts France
Show AbstractWith the increased use of explosives such as nitroaromatics in terrorist attacks, the development of efficient, portable and low-cost detection devices has become an urgent worldwide necessity. Since 10 years, many studies have been performed on the detection of nitroaromatics compounds using chemical gas sensors as highly sensitive and selective detectors of various explosives. Silica-based materials have ever been used as chemical sensor for humidity or NO detection. In this presentation, a new promising material based on nanostructured high-porosity silica films have been developed and tested as chemical sensors for nitroaromatics detection. Indeed, the chemical gas detection principle is based on the interaction between sensor surface and the target molecules at the solid-air interface. Such mesoporous silica material offers a very high specific area (>200m2/g) and allows to promote chemical sensor sensibility. On the other hand, the silica particle surface properties can be easily controlled by tailoring the surface hydroxyl groups density with the peptization solvent (water or ethanol) or by using surface functionalization such as specific species grafting. All those possibilities contribute to improve the detection performances in term of sensibility, selectivity and reversibility. The evaluation of detection performances using such functionalized nanostructured silica-based films as chemical sensors for quartz crystal microbalance and fluorescence devices exhibits remarkable results. Therefore, a specific hydrophobic silica thin film has been developed as detection material for quartz crystal microbalance sensors. Those systems show a good sensitivity (@ 0.1ppm) and reversibility for nitroaromatic compounds detection whatever the operating relative humidity conditions (from 0% to 80% at 20°C), Moreover, a silica-based fluorescent film have been selected for fluorescence sensors regarding it high sensitivity (@ 0.1ppm and @ 1ppm), it excellent reversibility (80% of fluorecent intensity), its robutness and its good selectivity towards the interfering volatil organic compounds. Today, we are currently evaluating the life-time duration of such sensors using functionalized nanostructured high-porosity silica-based films. The first results show that the quartz crystal microbalance sensors are operational during at least three months under air atmosphere.
5:45 PM - E11.10
Resonant Infrared Laser Assisted Transfer of Functionalized Nanoparticles into High Surface Area Assemblies.
Michael Papantonakis 1 , Duane Simonson 1 , Stephen Johnson 2 , Richard Haglund 2 , Erik Herz 3 , Ulrich Wiesner 3 , Eric Houser 4
1 Functional Materials and Devices, US Naval Research Laboratory, Washington, District of Columbia, United States, 2 Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, United States, 3 Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 4 Transportation Security Laboratory, US Department of Homeland Security, Atlantic City International Airport, New Jersey, United States
Show AbstractE12: Poster Session: Microfluidics and Assembly for Biological and Chemical Detection
Session Chairs
Changming Li
Larry Nagahara
Magnus Willander
Anis Zribi
Friday AM, December 01, 2006
Exhibition Hall D (Hynes)
9:00 PM - E12.1
Isolation of Viral RNA and mRNA from Mammalian Cells Via Solid-Phase Extraction on a Disposable Plastic Microchip.
Arpita Bhattacharyya 1 , Catherine Klapperich 1 2
1 Biomedical Engineering, Boston University, Boston, Massachusetts, United States, 2 Manufacturing Engineering, Boston University, Boston, Massachusetts, United States
Show AbstractObtaining high quality, intact RNA is often the most vital step in performing many fundamental biological experiments and molecular diagnostics. Current laboratory techniques for extraction of total RNA and mRNA requires several laborious bench-top procedures, which often puts the integrity of the RNA sample at risk. Moreover, the conventional techniques cannot be easily translated into point-of-care systems for ‘near-patient’ or ‘in-the-field’ diagnostic testing. Here we describe a new microfluidic technology for high-throughput isolation of total RNA from whole cell lysates, and subsequent selection of mRNA (Poly(A) RNA) from the isolated total RNA sample. The system is designed for disposable diagnostic applications in locations far-removed from a full service laboratory.The technology is based on the solid-phase extraction (SPE) of nucleic acids in a microfluidic platform. The microfluidic chips are fabricated in cyclic polyolefin by hot-embossing with a silicon master mold. The master itself is made using photolithographic techniques and Deep Reactive Ion Etching (DRIE). As a platform model, we tested the isolation of RNA from Madin-Darby Canine Kidney (MDCK) cells that were previously infected with Influenza A (H1N1) virus. The isolation of total RNA is done on-chip with a solid-phase extraction system formed by trapping silica particles in a porous polymer monolith. Separation of RNA is achieved through reversible binding of the nucleic acids to the silica particles in the monolith. The system provides efficient isolation of intact total RNA from whole cell lysates. The isolated RNA is then passed onto the next phase for the separation of mRNA from the total RNA sample. The solid-phase for mRNA isolation is formed with a porous polymer monolith impregnated with oligo(dT) attached to polystyrene beads. The isolation of mRNA is achieved due to the binding of the poly(A) tail of mRNA to the oligo(dT) beads entrapped in the monolith. This on-chip extraction technique provides high quality mRNA through efficient removal of ribosomal RNA (rRNA) and other non-mRNA species from the total RNA sample. Moreover, the system requires minimal user-handling, so the isolated sample has low risk of degradation. The mRNA is then used for downstream amplification and gene expression profile analysis.
9:00 PM - E12.10
Synthesis, Characterization, and Mechanical Properties of Metal Organic Frameworks.
Blake Simmons 1 , David Bahr 2 , Mark Allendorf 1 , William Mook 3 , Christina Bauer 1 , Neville Moody 1
1 , Sandia National Laboratories, Livermore, California, United States, 2 , Washington State University, Pullman, Washington, United States, 3 , University of Minnesota, Minneapolis, Minnesota, United States
Show AbstractRecently, a new class of nanoporous materials known as metal organic frameworks (MOFs) was created that have considerable potential for sensing, storage, and separation science. MOFs are crystalline materials with tunable, monolithic pore sizes and cavity properties. Their properties exceed those of virtually all other porous materials, including having the lowest known density, highest surface area, tunable photoluminescence, and high capacity for molecular adsorption. These exciting properties are achieved by coupling inorganic clusters such as Zn4O with tunable organic ligands that serve as struts, allowing facile manipulation of pore size and surface area through ligand selection. MOFs represent a hybrid inorganic/organic analog to purely inorganic zeolites, enabling rational synthetic design of nanoporous materials at the molecular level. Our initial work has focused on the synthesis and characterization of MOF-5 type materials. MOF crystal size, shape, and structure are very dependent on the conditions (temperature, solvent, time) utilized to synthesize them.One aspect of these materials that has not been thoroughly investigated to date is their intrinsic mechanical properties. We have used two different instruments to determine these properties for MOF-5 crystals through nanoindentation; a Hysitron Triboscoe and Nanoindenter XP. MOF-5 crystals were mounted to AFM stubs using super glue, which was applied to the puck. Crystals with faces perpendicular to the indentation direction were selected for mechanical evaluation of elastic modulus and hardness. The crystals looked to be a somewhat white / translucent color to the eye. Regions of relatively flat facets were probed using both quasistatic and continuous stiffness testing. Results from both techniques demonstrated that the MOF-5 crystals possess a modulus of between 2 and 5 GPa at depths beyond 300 nm, with differences between indentations likely due to surface topography. No evidence of fracture was observed; the deformation appears to be accommodated by either plasticity or densification, with slight evidence of adhesion between the diamond indenter tip and sample after deformation. The elastic modulus and deformation mode results are in generally good agreement with a recently published report that calculated the modulus of MOF crystals. Future efforts that will investigate the impact of the organic linker moiety on MOF physical properties will also be discussed.
9:00 PM - E12.11
Atomically Flat Gold Substrates for Single Molecule Characterization
Ajit Mahapatro 1 , Govind Mallick 2 , Shashi Karna 2 , David Janes 1
1 School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, United States, 2 Weapons & Materials Research Directorate, US Army Research Laboratory, Aberdeen Proving Ground, Maryland, United States
Show AbstractMolecular characterizations of single organic molecules are important for basic science study. Among the challenges in realizing well-controlled device structures is the difficulty in achieving metal surfaces with molecular scale roughness in characterizing the single molecule controlled patterned devices. This work demonstrates a technique to achieve gold (Au)-surface with roughness at the atomic scale using techniques compatible with integrated device fabrication. The technique utilizes room temperature e-beam evaporated Au films over a chemically grown self assembled monolayer of (3-Mercaptopropyl) trimethoxysilane (MPTMS) on oxidized silicon (SiO2) substrates. Atomic force microscope (AFM) image shows a rms surface roughness of ~1.8 Å over a 1 µm2 area and ~6Å over a 10 µm2 area. Surface topography over a 4 x 4 nm2 area using a scanning tunneling microscope (STM) reveals the Au atom arrangements in the same plane, indicating a hair like curly line patterns of Au atoms and inter-structure separation of ~2.5 Å (average Au-Au distance). A conductivity of 2.7 x 105 Ω-1cm-1 is measured for the Au (200Å)/MPTMS/SiO2 films, which is comparable to the value 4.1 x 105 Ω-1cm-1 for bulk Au. We have successfully assembled monolayers of σ- and π- bonded molecular chains on the Au substrate. Initial surface probe microscope characterization suggests bundles of well organized molecular domains on the substrate. This study indicates that the atomic flat Au films prepared in this technique will be useful as an efficient substrate for single molecule characterizations that includes well-ordered self assembled monolayer (SAM) and electrical properties. The electrical measurements through single molecules (by approaching a STM tip towards SAM of various organic molecules) and many molecules (by placing a top contact through stamping processes) can be observed through an electrode-molecule-electrode junction in the same test bed.
9:00 PM - E12.12
Characterization of Reversible Protein Trapping Through Neutron Reflectometry
Todd Monson 1 , Benjamin Frankamp 1 , Dale Huber 1 , Viengkeo Bounkeua 1 , Bruce Bunker 1 , Erik Watkins 2 , Jaroslaw Majewski 2
1 Nanostructure & Semiconductor Physics, Sandia National Labs, Albuquerque, New Mexico, United States, 2 Los Alamos Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Show AbstractReversible protein trapping by poly(N-isopropylacrylamide) (PNIPAM) films was investigated through neutron reflectometry, ellipsometry, and atomic force microscopy (AFM). PNIPAM films take advantage of a hydrophilic/hydrophobic transition that occurs at the polymer’s lower critical solution temperature (LCST), which for our PNIPAM films is ~ 35°C. Below 35°C the polymer film is hydrophilic and swells in aqueous solutions. Above 35°C PNIPAM transitions to a less hydrophilic state, collapses, and traps proteins. Thickness and densities of captured films of the antibody Immunoglobulin G (IgG) as well as the tobacco mosaic virus (TMV) bound to TMV specific IgG were determined. This information was further supported by ellipsometry and AFM measurements. AFM measurements also provided insight into the orientation of the captured TMV rod-like structures. These polymer films possess a unique thermal reversibility that makes them excellent candidates for use in a variety of detection schemes. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
9:00 PM - E12.13
Vertically Aligned Self-assembled DNA Oligonucleotides on Arsenic-terminated GaAs.
Joon Hyuk Yang 1 , Bindhu Varughese 2 , Mohamad Al-Sheikhly 1 , Lourdes Salamanca-Riba 1
1 Department of Materials Science and Engineering, University of Maryland, College park, Maryland, United States, 2 Department of Chemistry, University of Maryland, College Park, Maryland, United States
Show AbstractImmobilization of DNA on a variety of substrates has recently become an important field because of its potential applications in molecular electronics and biomolecular sensors. Semiconductors in particular are good candidate substrates for these applications. We have investigated the attachment of thiolated, rod shaped, eight base single-stranded DNA on As-terminated GaAs substrates. The attachment of thiolated DNA oligonucleotides on the GaAs was achieved through covalent bonding between the As of the GaAs and the S of the thiol group laced to the DNA. Some undesired bonding also took place between N- and O- from the DNA with As from the GaAs substrate. The addition of 6-mercapto-1hexanol (MCH) was used for establishing a uniform layer whereby sulfur from the MCH displaced the undesired N-As and O-As bonds. Our XPS results showed that as the MCH concentration increased, the ratio of atomic concentration of S/As increased while the ratio of N/As and O/As bonds decreased. In order to understand the nature of this attachment, the effects of ionic strength of the buffer solution, the DNA concentration, and MCH concentration were investigated. The structural properties of brush-like DNA layer were studied using Atomic Force Microscopy (AFM) with a Fluid Imaging Cell, X-ray Photoelectron Spectroscopy (XPS), and Environmental Scanning Electro Microscopy (ESEM). This work was supported by the Department of Energy-Innovations under the Nuclear Infrastructure and Education (INIE) program.
9:00 PM - E12.14
Hydroxyl Adsorbtion on Rutile TiO2(110) Observed by using Scanning Tunneling Microscopy.
Sefa Dag 1 , Vincent Meunier 1 , Minghu Pan 1 , K. Park 2 , E. Plummer 3
1 Center of Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 2 Department of Physics, Baylor University, Waco, Texas, United States, 3 Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee, United States
Show Abstract9:00 PM - E12.15
Nanometric Chemical Sensing of Solution Ionic Concentrations Above Surfaces
Aaron Lewis 2 1 , Patricia Hamra 1 2 , Chaim Sukenik 3
2 Applied Physics, Hebrew University of Jerusalem, Jerusalem Israel, 1 , Nanonics Imaging, Jerusalem Israel, 3 Chemistry, Bar Ilan University, Ramat Gan Israel
Show Abstract9:00 PM - E12.18
Quantification of the Interaction Between Folate Binding Protein and PAMAM Dendrimers Functionalized with Folic Acid via Force Pulling Spectroscopy.
Pascale Leroueil 1 2 , Craig Blanchette 8 , Stassi DiMaggio 7 2 , Seungpyo Hong 5 2 , James Baker 2 , Christine Orme 6 , Bradford Orr 4 3 2 , Mark Banaszak Holl 1 5 2
1 Department of Chemistry, University of Michigan, Ann Arbor, Michigan, United States, 2 Michigan Nanoscience Institute for Medical and Biological Sciences , University of Michigan, Ann Arbor, Michigan, United States, 8 Biophysics Graduate Group, Division of Biological Sciences, University of California, Davis, Davis, California, United States, 7 Chemistry, Xavier University, New Orleans, Louisiana, United States, 5 Program of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan, United States, 6 Department of Chemistry and Materials Science, Lawrence Livermore National Lab, Livermore, California, United States, 4 Department of Physics, University of Michigan, Ann Arbor, Michigan, United States, 3 Program of Applied Physics, University of Michigan, Ann Arbor, Michigan, United States
Show AbstractOver the past decade, our group has developed PAMAM dendrimers as a drug delivery platform. The dendrimer surface is modified to include not only the drug itself, but a targeting agent, folic acid (FA). FA was chosen as the targeting agent because the folate receptor (FAR) is known to be over-expressed on the surface of several epithelial cancer cell lines. Investigation by a number of techniques, including confocal microscopy, flow cytometry and surface plasmon resonance, have shown that the efficacy of this drug delivery agent has a strong dependence on the number of targeting moieties attached to the dendrimer platform. In this talk we report on the use of atomic force microscopy (AFM) to perform single molecule force pulling experiments to quantify the interaction between a model folate receptor (fetal bovine protein, (FBP)) and FAs which have been conjugated to dendrimers. The FA-conjugated dendrimers were attached to an AFM tip via a polymer tether and then brought into contact with a FBP-modified surface. Force curves were obtained and analyzed for dendrimers with 0, 3, 6 and 9 FAs. By varying the number of FAs per dendrimer, we were able to quantify the change in adhesion force associated with multiple FA/FBP interactions and increase our understanding of polyvalent targeting.
9:00 PM - E12.19
Patterning of Block Copolymers and Biomaterials using Microcontact Printing and Dip-pen Nanolithography.
Amol Chandekar 1 2 3 , Sandip Sengupta 1 2 3 , James Whitten 1 2 3
1 Chemistry, University of Massachusetts Lowell, Lowell, Massachusetts, United States, 2 Center for High-Rate Nanomanufacturing , University of Massachusetts Lowell, Lowell, Massachusetts, United States, 3 Center for Advanced Materials, University of Massachusetts Lowell, Lowell, Massachusetts, United States
Show Abstract9:00 PM - E12.2
Electrostatic-Directed Deposition of Nanoparticles on a Field Generating Substrate
De-Hao Tsai 1 3 , Michael Zachariah 1 3 , Raymond Phaneuf 2 4 , Kuk Choi 1 3 , Takumi Hawa 1 3
1 Mechanical Engineering, University of Maryland, College Park, Maryland, United States, 3 , National Institute of Standard Technology, Gaithersburg, Maryland, United States, 2 Material Science and Engineering, University of Maryland, College Park, Maryland, United States, 4 , Laboratory for Physical Science, College Park, Maryland, United States
Show AbstractFunctional nanoparticles have been widely considered as the building blocks of potential micro- and nano-scale electronic, optoelectronic devices and gas sensors. For many applications of nanoparticles, in for example sensors or other electronic devices the precise positioning for integration into a working device becomes a considerable challenge. The production of nanoparticles using gas phase methods has the advantage of a clean, continuous process, which can be operated at atmospheric conditions without requiring any vacuum environment or solvent medium. An additional advantage is that charge can be readily placed on nanoparticles, which can be used both to conduct size selection or filtration, and to direct deposition through the implementation of electric fields. We demonstrate a new assembly method to position Ag nanoparticles delivered from the gas phase onto surfaces using the electrostatic force generated by biased p-n junction patterned substrates. The choice of silver was based on an eventual goal of using these particles for surface plasmon resonance (SPR) bio-sensing devices. Aligned deposition patterns of size-selective Ag nanoparticles generated by the aerosol process were observed, and the patterning selectivity quantified. Furthermore, we have developed a trajectory model applied for positioning metal nanoparticles from the gas phase onto electrostatic-patterns generated by biasing P-N junction substrates. Brownian motion of nanoparticles as well as the interactions between the charged nanoparticles and the patterned substrate, including electrostatic force, image force and van der Waals force, has been taken into account during simulation. Besides, a convective flow parallel to the substrate surface has also been included in the particle trajectory. The simulation results were compared with experimental observations of silver nanoparticle patterns. The high coverage selectivity observed for Ni nanoparticles was also achieved by Ag nanoparticles, indicating that this method was applicable to a variety of metal nanoparticles. We have also investigated the effects of the particle size, electric field intensity, and the convective flow through both experiments and simulations. A non-dimensional analysis of the competition between the electrostatic force and the diffusion force was found to provide a good strategy to determine optimum conditions for this assembly process.
9:00 PM - E12.20
Dip Pen Nanolithography™: A Maturing Technology for High-Throughput Flexible Nanopatterning.
Jason Haaheim 1 , Joe Fragala 2
1 product development, NanoInk, Inc., Skokie, Illinois, United States, 2 microfabrication, NanoInk, Inc., Campbell, California, United States
Show AbstractPrecision nanoscale deposition is a fundamental requirement for much of current nanoscience research. Further, depositing a wide range of materials as nanoscale features onto diverse surfaces is a challenging requirement for nanoscale processing systems. As a high resolution scanning probe-based direct-write technology, Dip Pen Nanolithography™ (DPN®) satisfies and exceeds these fundamental requirements. Recent advances in large array patterning point to breakthrough applications in high-throughput, flexible nanopatterning. DPN is fundamentally a bottom up nanoscale deposition technique (i.e., templated assembly for biological detection); however, direct-write with etch resist “inks” leads to a powerful form of top down nanofabrication. NanoInk’s new 2D arrays enable massively parallel nanoscale deposition with 55,000 pens. Further, DPN biomolecule deposition coupled with large area 2D nanoscale patterning opens up a completely new area of single particle biology. Researchers have demonstrated nanoscale site-specific placement of single biomolecules (TMV virus, Influenza A, and HIV) on MHA templates, maintaining almost 100% bioactivity. Researchers have also detected HIV in patient samples by using a DPN-generated nano-immunoassay that exceeds the detection limit of ELISA by more than 1000X. Further, single particle site isolation is critical for studying the behavior of individual viruses. In addition to suggesting novel methods for studying the effectiveness of new drugs and delivery techniques, this technology allows users to routinely pattern libraries of small molecules over very large areas, and realistically practice single cell experimentation. Relative to other nanopatterning techniques, DPN is a direct-write technique maintaining high resolution (14 nm line widths, 20 nm pitches), and among sub-50 nm techniques, DPN is the only one that can directly deposit molecules under ambient conditions. In addition, because NanoInk’s nanolithography platform – the NSCRIPTOR™ – is based on scanning probe microscopy (SPM) technology, it is inherently capable of both pattern fabrication and immediate verification of the result by imaging. Throughput is an area where DPN now offers dramatic increases: NanoInk’s 2D arrays of 55,000 pens can cover a square centimeter with nanoscale features and pattern 10^7 μm^2 per hour. These advances point the way to true high-throughput nanomanufacturing. Herein, we show examples of massively parallel bottom up nanofabrication via single biomolecule templating and oriented carbon nanotube attachment. We also report top down nanofabrication to flexibly create large arrays of metallic nanostructures.
9:00 PM - E12.23
Assembly of Metal Nanoparticles Mediated by Structurally-Tunable Mediators
Stephanie Lim 1 , Jin Luo 1 , Wui Ip 1 , Chuan-Jian Zhong 1
1 Chemistry, State Univ. of New York at Binghamton, Binghamton, New York, United States
Show AbstractNanostructured materials have received enormous attention due to their promising applications in the fields of sensors and catalysis. While the optical, magnetic, catalytic, and electronic properties of nanoparticles and nanostructures are interesting, many applications are hampered by the lack of ability to assemble nanoparticles with controllable sizes, shapes, and interparticle spatial properties. This presentation reports the results of an investigation of the assembly of metal nanoparticles using fullerenes, dyes, proteins, and thioethers as mediators. These mediator structures have intriguing fine-tunable properties, including structural rigidity, multifunctional binding sites, π-conjugation, and controlled 2D/3D shapes and sizes. Both water-soluble gold nanoparticles (1-100 nm) and organic-soluble gold nanoparticles (2-10 nm) are studied as model systems. The combination of these building blocks allows the creation of an entirely new array of nanostructures with desired sizes and shapes that have important implications to the design and exploration of novel functional nanostructures. Various spectroscopic and microscopic techniques are utilized to characterize the nanostructured assemblies. One important finding is that the interparticle spatial or chemical properties of the network nanostructures can be finely tuned by chemical stimuli, which could lead to novel optical properties for potential applications in biological/chemical sensing, controlled drug delivery, micro/nano electronics, and photosensitive or luminescent devices.
9:00 PM - E12.24
Single-Liposome Array Pattern by Surface Functionalization Integrated with Colloidal Lithography
Hee Uk Lee 1 , Dong June Ahn 1 , Gil Sun Lee 1 , Myung Mo Sung 2
1 Chemical & Biological Engineering, Korea University, Seoul Korea (the Republic of), 2 Chemistry, Hanyang University, Seoul Korea (the Republic of)
Show AbstractPolydiacetylene (PDA) supramolecules have attracted much interest due to unique characteristic of color changing from blue to red upon specific binding events. Also, it is known that they are self-emitting red fluorescence in red phase, but no fluorescence in blue phase. Many researchers have published that various binding events including influenza virus, toxins, glucose, DNA, protein, and so on could be detected with color and fluorescence change of PDA supramolecules. But those results were obtained mostly from solution experiments. However, it is hard to improve the detection sensitivity because the amount of PDA liposomes being used in detection is much larger in case of solution. The best method to overcome such a limit is to minimize the amount of PDA liposomes, that is, to use a single liposome.In this study, as a first step to fabricate a single-liposome sensor or chip, we have investigated formation of single PDA liposome array patterns on silicon dioxide substrates by surface functionalization integrated with colloidal lithography. Firstly, nanopatterns (70-100 nm) were formed on substrates after colloidal lithography and self assembly of octadecyltrichlorosilane (OTS). Secondly, PDA liposome arrays were formed by the reaction between PDA liposome and nanopatterns. Finally, we confirmed that the array is single liposome with atomic force microscopy. If this array technique is combined with scanning near-field optical microscopy (SNOM), we will be able to significantly improve the detection sensitivity of analytes such as DNAs and antibodies.
9:00 PM - E12.25
Cytotoxicity of the Functionalized Gold and Silver Nanorods
Chiung Wen Kuo 1 2 , Jun-Jung Lai 1 , Kung Hwa Wei 2 , Peilin Chen 1
1 Research Center for Applied Sciences, Academia Sinica, Taipei Taiwan, 2 Department of Material Science and Engineering, National Chiao Tung University, Hsin Chu Taiwan
Show Abstract9:00 PM - E12.26
Fabrication of Biomimetic Superhydrophobic Structures on Polymer Surface by using Patterned Anodic Aluminum Oxides (AAO) as a Replication Master.
Yuwon Lee 1 , Sang-Hyun Park 2 , Ki-Bum Kim 2 , Jin-Kyu Lee 1
1 Chemistry, Seoul national university, Seoul Korea (the Republic of), 2 Materials Science and Engineering, Seoul national university, Seoul Korea (the Republic of)
Show Abstract9:00 PM - E12.27
Holographic Fabrication of 3-dimensional Nanostructures for Optofluidic Integration
Seung-Kon Lee 1 , Seung-Man Yang 1 , Jun Hyuk Moon 2
1 National CRI Center for Integrated Optofluidic Systems and Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon Korea (the Republic of), 2 Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractMulti-dimensionally fabricated microstructures inside microchannels are of great importance for microfluidic mixing, microscale separation of biological materials, chemical microsensors, macroporous matrices of catalysts, microfluidic control of light such as optical waveguides. Although the methods based on colloidal self-assembly were able to produce high quality three-dimensional photonic nanostructures without machinery, those were not quite practical because it took a long process time with extremely limited controllability compared with the conventional lithographic technique.In this study, we reported new strategy integrating holographic lithography with photo-lithography for hybrid patterns of microchannels and 3-dimensional nanostructures. Microchannels were generated by photo-lithography and 3-dimensional nanostructures were fabricated by using holographic lithography inside of the channels. This hybrid structures could be applied to the passive microfluidic mixers and filters due to the interconnected pores of 3-dimensional nanostructures. On the other hands, hybrid structure could be applied to the optofluidic platform; the combination of the microfluidics and photonics. Holographically fabricated 3-dimensional structures have photonic band-gap property due to their structural periodicity and microfluidic channels give adaptive controllability of the refractive index. Since the photonic band-gap properties of 3-dimensonal nanostructures can be tuned by the refractive index mismatches between two different materials, it can be used as tunable waveguide and optical filters. By same principles, it can detect the chemical and bio-materials from the photonic band-gap shift. Only small amount of sample is needed in these optofluidic devices since the volume of the microfluidic channel is nanoliter scale and the sample species can be detected immediately by optical signals associated with photonic band-gaps. Therefore, microscale optofluidic chips are useful for the diagnostics and chemical or bio sensors with infinitesimal amount of the samples. On the other hand, the fluidically modulated photonic band gaps of built-in photonic crystals are essential for constructing optofluidic platforms, which require fluidic addressability and adaptive controllability. Therefore, the microfluidic chips with built-in photonic crystals have potential applications for active photonic devices such as optical waveguides, filters, switches and adaptable photonic circuits.
9:00 PM - E12.28
Use of Anodized Titanium in Drug Delivery Applications
Chang Yao 1 , Ganesan Balasundaram 1 , Thomas Webster 1
1 , Brown University, Providence, Rhode Island, United States
Show AbstractOne approach to improve the performance of current titanium implants is to create nanostructures via surface modification. Anodization is known to produce nanotubular structures on titanium surfaces when using fluorine containing solutions. Previous studies revealed enhanced osteoblast (bone-forming cell) adhesion and calcium deposition on anodized titanium possessing nanotubular structures compared to unanodized titanium. Moreover, it was found that protein adsorption (specifically, vitronectin and fibronectin) prior to cell adhesion increased on anodized compared to unanodized samples. These results all indicate that anodized titanium would be a good candidate for novel orthopedic implants. The nanotubes created by anodization have an inner diameter from 40 to 100 nm and a depth of a few hundred nanometers. In the present study, the drug delivery capability of such nanotubular structures was further characterized. Three different model drugs were tested: immunoglobulin G for foreign body response, bone morphogenetic protein active fragment for new bone growth, and penicillin/streptomycin for antimicrobial activity. First, these proteins were allowed to adsorb onto the substrates for 24 h under room temperature. Then, the substrates with absorbed proteins were rinsed and transferred to a new buffer solution kept at 37 degree C. Buffer solution was collected and changed everyday. Finally, protein release from each substrate was measured using a commercial BCA assay kit. Results showed decreased immunoglobulin G adsorption, increased bone morphogenetic protein and penicillin/streptomycin adsorption on anodized compared to unanodized titanium. The release behavior of each protein on anodized and unanodized titanium will also be presented. In this manner, these results suggest that titanium substrates anodized to possess nanotubes are useful in orthopedic drug release applications.
9:00 PM - E12.29
Endothelial Cell Adhesion on Highly Controllable Compared to Random Nanostructured Titanium Surface Features
Jing Lu 1 , Thomas Webster 1
1 Division of Engineering, Brown University, Providence, Rhode Island, United States
Show AbstractMuch attention has been paid to modifying vascular stent surfaces to promote the formation of an endothelial layer. Due to their ability to mimic the surface roughness of natural tissue, nanostructured metals have been a focus of this investigation. However, it is currently not known whether random versus controllable nanostructured surface features are more beneficial towards creating an endothelial layer important for vascular stent function. To test this, two kinds of modifications were created in this study: highly controllable nanostructured surface features and random nanostructured surface features. Random nanostructured surface features were created on titanium by compacting titanium nanoparticles (~100nm) through standard powder metallurgy techniques. Highly controllable nanostructured surface features were created through high precision photolithography techniques. To analyze the adhesion of endothelial cells on the titanium samples of interest, they were first seeded and then allowed to adhere for 4 hours. At the end of the prescribed time period, the substrates were rinsed in phosphate buffered saline. The viability of adherent cells was determined using a live/dead assay, indicating enhanced cell adhesion on those nanopatterned surfaces compared with that of random nanostructured surfaces. Fluorescence microscopy analysis demonstrated that on the highly controllable nanostructured titanium surface features, endothelial cells were well spread and aligned along the nanolines. In this manner, the results of this study could help endothelial cells adhere and, thus, form a monolayer with an elongated morphology that mimics that observed in the natural vascular for improved titanium stent applications.
9:00 PM - E12.3
A Novel Gas-phase Hydrogen Peroxide Sensor Basing on a Combined Physical/chemical Transduction Mechanism.
Niko Naether 1 , Ruediger Emmerich 2 , Joerg Berger 2 , Peter Friedrich 2 , Hartmut Henkel 3 , Michael Schoening 1
1 Aachen University of Applied Sciences, Laboratory for Chemical- and Biosensors, Juelich Germany, 2 SIG Combibloc Systems GmbH, Future Technology, Linnich Germany, 3 , von Hoerner & Sulger Systems GmbH, Schwetzingen Germany
Show Abstract9:00 PM - E12.30
In-Situ Construction of Low-Dimensional Transition-Metal Oxides and Separation of Aromatic Amines by Selective Intercalation.
Boon Loo 1 , Ke Shao 2 , Jiannian Yao 3
1 Chemistry, Towson University, Towson, Maryland, United States, 2 Chemistry, Shenzen University, Shenzen China, 3 , Chinese Academy of Sciences, Beijing China
Show AbstractLow-dimensional materials have been widely investigated because of their properties in chemical storage, superconductivity, proton conductivity, ionic exchange and others. New methods of preparing new low-dimensional materials, reaction routes and mechanism have been intensely investigated. We report here the synthesis of two low-dimensional transition-metal oxides, using pi-pi conjugated metal-ligand (M-L) complexes as inducing templates via a one-step method. To our knowledge, this is the first example of its kind. The complex molecules act as templates and induce the formation of metal oxide matrix, in which the complex molecules can be inserted. We ascribe the complex molecules as the guests and the molybdenum oxide matrix as the host. The pi-pi overlap between the metal and ligands provides sufficient guest-guest interactions which contribute to the formation of the M-L complex/metal oxide host-guest superstructures. In this way, two typical low-dimensional structures have been obtained; the layered molybdenum oxide and the porous tungsten oxide, both of which are well-known catalysts and photochromic materials. In our experiment, these two host matrices were obtained by hydrolysis of ammonium molybdate and sodium tungstate in acidic conditions. The characteristic layered structure of molybdenum oxide makes it a good host material for intercalation, whereas the tungsten oxide polyanions assemble into hexagonal phases. An excellent template, a dye molecule, Fe(II)-5-NO2-phen complex (phen = 1,10-phenanthroline) was introduced during the hydrolysis process, acting as the guest species. In a layered inorganic matrix, the guest molecules usually anchor to the host layers via reactions such as oxidation-reduction, ion exchange, acid-base, or donor-acceptor, etc. However, these intercalation processes usually take place without selectivity. Hence, there exists high motivation in research on selective intercalation of the guest species for industrial and environmental applications. In a separate experiment, we show an example of selective intercalation of aromatic amine molecules into transition metal oxide layers. The layered structure molybdenum oxide is used as a host to selectively intercalate aromatic o-phenylenediamine. Polymerization of o-phenylenediamine in between the molybdenum oxide layers makes o-phenylenediamine a good template. Along the linear polymer chain, the molybdenum oxide layers grow simultaneously. This templating ability renders it a preferential guest species when compared to aniline. In this way, o-phenylenediamine can be selectively intercalated and separated from its mixture with aniline.
9:00 PM - E12.31
Biocompatible Ceramics for Implants Based on Calcium Phosphates.
Tatiana Safronova 1 , Valery Putlayev 1 , Alexandr Veresov 2 , Anton Kuznetsov 2 , Mikhail Shekhirev 2 , Kamilla Agahi 3
1 Chemical Department, MSU, Moscow Russian Federation, 2 Department of Materials Science, MSU, Moscow Russian Federation, 3 Institute of Mechanics, MSU, Moscow Russian Federation
Show AbstractHydroxyapatite (HAp), tricalcium phosphate (TCP) and calcium pyrophosphate (CPP) are known to be among calcium phosphates used in clinical medicine due to their biocompatibility. HAp and other complex calcium phosphate salts are the end-products of the biological mineralization process. Calcium pyrophosphate Ca2P2O7 (β-CPP) is one of the intermediate products involved in this process. The biological response with respect to new bone formation is quite similar for CPP and HAp. Sintered CPP has better biological responses, and, thus, a great potential as a biodegradable bone substitute. The rate of biodegradation depends on: (i) material texture (porosity type and level), (ii) quality of biodegradation phase (phase composition, grain size, properties of grain boundaries). Several sources for CPP phase in ceramics can be assumed. CPP phase may come from frit (CaO-P2O5, Ca/P=0.2-0.75) used as a sintering additive. Ceramics can be fabricated from powder of CPP with Na4P2O7 as sintering additive, via interaction between H3PO4 or (NH4)2HPO4 and porous HAp at high temperature after soaking it in the former solutions. The aim of the present work was focused on fabrication of multiphase ceramics with enhanced resorptivity due to presence of CPP phase and investigation of processes leading to formation of the multiphase ceramics based on HAp and CPP originated from CaHPO4. Ceramic materials have been made from mixtures of powders of stoihiometric HAp (Ca/P=1.67) and monetite (CaHPO4, Ca/P=1). Powders of HAp and monetite were synthesized by means of wet chemical precipitation from aqueous solutions of Ca(NO3)2*4H2O and (NH4)2HPO4 at 60 C and pH=9 for HAp and pH=4-5 for monetite. Component ratio HAp:monetite was varied from 0:100 to 100:0 % with a step of 20%. Powders of raw materials and the mixtures were tested by means of XRD, TG, DTG, SEM, dilatometry. Linear shrinkage, density and microstructure of samples of ceramic materials sintered at 900, 1000, 1100 C with isothermal holding during 6 hours were tested. Complicated consequence of phase transformations took place during heating the the mixtures from 20 to 1200 C. The CPP (Ca/P=1, converted from CaHPO4 at 400-500 C ) reacts with HAp (Ca/P=1.67) causing additional weight loss in the region of 600-1050 C due to solid state reaction leading to TCP (Ca/P=1.55) formation. Linear shrinkage of HAp at 1100 C after 6 hours was found to be about 21%; for Ca2P2O7 formed from monetite, and for the mixtures - less than 11%. Resulted ceramics with the phase composition of HAp, CPP and TCP, i.e. with a different content of degradable phase and different ratio of CPP/TCP, can be treated as a biocompatible bioactive material with a tunable rate and limit of biodegradation.The work was supported by RFBR (grants #05-03-32768, #05-08-50256)
9:00 PM - E12.32
Advanced Organic-inorganic Hybrid Coatings Having Both High Gas Barrier Properties and Abrasion Resistance.
Katsunori Nishiura 1 , Toshihiko Takaki 1 , Makoto Nakaura 2
1 Material Science Laboratory, Mitsui Chemicals, Chiba Japan, 2 , Mitsui Chemical Analysis & Consulting Service Inc., Chiba Japan
Show AbstractIt is important to develop flexible transparent polymer films having high gas barrier properties and abrasion resistance because new applications involving transparent polymer films for flat panel displays require these properties. The traditional approach to providing high gas barrier properties for polymer films is the well-known dry coating process, in which polymer films are coated by the vapor deposition of metal oxides such as SiO2 or Al2O3 on their surface. Although dry coating can give polymer films high gas barrier properties, abrasion resistance is not improved by this method. Therefore, the dry coating process needs hard coatings to protect the polymer films from scratches, and hard coatings are usually produced by a wet coating process. Organic-inorganic hybrid materials are used for hard coatings because of their excellent hardening properties, however, it is difficult to produce hard coatings with high gas barrier properties equivalent to those produced by the dry coating process.We report on organic-inorganic hybrid coatings of polyvinylalcohol (PVA)/polyacrylicacid (PAA)-silica, which have high gas barrier properties almost equivalent to those achieved by the dry coating process. The hybrid coatings were prepared by the sol-gel reaction of alkoxysilane in a PVA/PAA aqueous solution. A crosslinking agent was added in the coating solution to accelerate esterification between PVA and PAA at a relatively low temperature, in order to keep the high gas barrier properties even in high humidity conditions. The resulting solution was coated onto the polymer substrate using a bar-coater then cured by heating. In order to obtain transparent coating films 3-aminopropyltrimethoxysilane (APTMOS) was used as a compatibilizer in the sol-gel reaction of tetramethoxysilane (TMOS). No structure could be seen in the TEM of the cross-sectional coating layer, indicating that polymers and silica were mixed homogeneously.The hybrid coatings were shown to have excellent abrasion resistance based on the ΔHaze index, which is the difference between the haze number measured before and after Taber’s abrasion test.Gas barrier properties were evaluated by MOCON under the conditions of 23 oC, 90%RH, and little effect on O2 permeability was observed for PVA/PAA coated PET in such a humid condition. O2 permeability decreased as silica content increased in the coatings. Unexpectedly, high gas barrier properties appeared when the silica content exceeded 50 wt%: when the silica content was 55 wt%, O2 permeability achieved 0.4 cc/m2. Because these high gas barrier properties strongly suggest a drastic morphological change of organic-inorganic hybrid coatings, we will show the EF-TEM results to explain why such high gas barrier properties were obtained.
9:00 PM - E12.33
Detection of Si/F-C and C-H/F-C Weak Interactions of Fluoroalkylated Polysilane Copolymers and Application to Building-up of Super-Hierarchical Structures
Takuma Kawabe 1 , Masanobu Naito 1 , Michiya Fujiki 1
1 Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara Japan
Show AbstractNon-classical weak interactions, such as C-H/pai, C-H/O, and C-H/F-C, have received much attention theoretically and experimentally, because the weak interactions play an essential role in organizing highly ordered structures and sophisticated functions, especially in biological and supramolecular systems. Most of these interactions influence the thermodynamic process from the meta-stable and/or intermediate states to the most stable state. It is, therefore, difficult to detect these interactions with conventional analytical techniques, with a few exceptions, e.g. X-ray structural analysis and theoretical calculation. Here we report that two types of non-classical Si/F-C and C-H/F-C weak interactions can be detected in certain rod-like polysilane block copolymers composed of methyl-3,3,3-trifluoropropylsilane and n-decylisobutylsilane at ambient temperature. The fluoroalkylated polysilane copolymers were prepared by Wurtz type condensation reaction of methyl-3,3,3-trifluoropropyldichlorosilane and n-decylisobutyldichlorosilane with sodium in hot toluene at 120 °C. Si-NMR spectra revealed that this copolymerization formed multiblock like manner, correlating to the initial composition ratio. Those Si/F-C and C-H/F-C weak interactions were investigated by a combination of H-, Si-, F- NMR, UV, IR, TEM, and AFM measurements, followed by calculating a binding energy of those weak interactions in a polymer system. The fluoroalkylated polysilane copolymers provided a highly ordered polymer gel, probably on account of the cooperative effect of weak interactions. Indeed, non-classical weak interactions, Si/F-C and C-H/F-C, were successfully observed by the aforementioned methods in the polysilane copolymer gel. We will discuss in detail, the effects of solvents, aging time, and molecular weight.
9:00 PM - E12.34
Precision Nano-structure Fabrication for the Investigation of Cell-substrate Interactions.
Shelley Dougherty 1 , Jianyu Liang 1 , George Pins 2
1 Materials Science and Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, United States, 2 Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, United States
Show Abstract9:00 PM - E12.35
Time Response Behavior Of Segmented Tin Dioxide Layers To Stepwise Changes Of the Electrical Potential Under Air Exposure.
Joachim Goschnick 1 , Ilia Kiselev 1 , Vyacheslav Simakov 2
1 Institut für Mikrostrukturtechnik, Forschungszentrum Karlsruhe, Karlsruhe Germany, 2 Department of Chemistry, Saratov State Technical University, Saratov Russian Federation
Show AbstractThin films of semiconducting metal oxides (mox) as SnO2 are widely used in gas analytical devices. The electrical conductivity is sensitively depending on the composition of the adjacent air. Gas components adsorb at the mox surface, influence the electronic properties of the film and reactive ionosorbed oxygen feeds a catalytic oxidation. Often arrays of gas sensors are used to allow an online characterization of gas ensembles. Mostly, the conductivity measurements at the array elements are made sequentially to connect one sensor after the other to the same measuring circuit. Hence, additionally to the gas dynamics the electrical response speed of a mox element determines the overall measuring rate of a given sensor array. Therefore, the transient electrical response of a sputtered nanocrystalline Pt-doped SnO2 film (n-type semiconductor) was studied which is used as gas detector in a gradient gas sensor microarray. The latter consists of a single 150nm thick and 4X8mm wide SnO2 film on an oxidized Si substrate. The mox film is subdivided by 39 sputtered Pt strips with a width of 90µm and a thickness of about 1µm shutting in 100µm wide SnO2 areas. In most experiments the SnO2 film was hold at 300°C by internal heaters and flushed with 1lit/min humidified clean air.The transient electrical behavior of the sensor segments was measured with sudden applications of 1-20V to one of the electrodes. The multitude of electrodes was deployed to measure dynamically the spatial potential distribution with 100msec resolution on both sides to a Feeding Electrode (FE) amidst the electrode pattern after a positive voltage was applied to the FE while the other electrodes were floating. Despite the small capacity of Pt electrode couples (several pF) a considerable charging current corresponding to ~1 μF capacity passed through the FE after the voltage was engaged lasting up to 10 min until all electrodes reached the stationary potential equal to the FE value. However, the potentials of the floating electrodes are already near the FE potential very soon after the voltage is connected. Then, for ca. 3 sec, the potentials are falling until a minimum is passed followed by a long recovery over several min. The higher the applied voltage and the greater the distance to the FE, the longer is the transient period and the steeper is the potential minimum. Increasing the film temperature reduces the effect. Application of a negative potential had nearly no effect. This behavior cannot be explained by a simple ohmic resistor. Indeed, a gas insensitive Cr2O3 film of the same dimensions did not show such effects.Presently, a chemical process seems to be the most probable explanation involving a rearrangement of the ionosorbed oxygen and/or adsorbed polar water molecules at the SnO2 surface. From the practical point of view a fast response can be achieved by d.c. measurements keeping the applied voltage ≤ 1V or negative and the temperature as high as possible.
9:00 PM - E12.36
Self assembly of Colloidal Particles on a Nanostructured Template Coated with Polyelectrolyte Multilayers.
Yong Hoon Kim 1 , Juhyun Park 2 , Paula Hammond 1
1 Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show Abstract9:00 PM - E12.37
Functional Patternings Fabricated using Molecularly Imprinted Polymer; Molecular Recognitions for Chemical Detection.
Kyung Choi 1
1 , Bell Labs, Lucent Technologies, Murray Hill, New Jersey, United States
Show Abstract9:00 PM - E12.38
Fabrication of Patterned Crystalline Au(111) Surfaces as a Template for Self-assembled Monolayer of Organic Molecules.
Young Kyu Hong 1 , No A Lee 1 , Hyunung Yu 1 , Nam Woong Song 1 , Tae Geol Lee 1 , Jae Ho Bahng 1 , Ja-Yong Koo 1
1 , Korea Research Institute of Standards and Science, Daejeon Korea (the Republic of)
Show Abstract9:00 PM - E12.4
Custom-Designed Nesting Sites for Peptides on Optimally Doped Material Surfaces
Boyang Wang 1 , Petr Kral 1
1 Chemistry, University of Illinois at Chicago, Chicago, Illinois, United States
Show AbstractWe develop a methodology of optimal doping of material surfaces that allows designing of selective nesting sites for molecules. The idea is to modify material surfaces by electron donors and acceptors in such a way that the local electric fields created around the dopants form Coulombictraps for inorganic, organic or biological molecules. We theoretically demonstrate this approach by designing nesting sites for small peptides on graphene sheets substitutionally doped with B and N atoms. We showthat the formed traps are highly selective and can recognize among an ensemble of peptides the one for which they are created. This methodology opens the path for designing of novel hybrid multi-functional systems.
9:00 PM - E12.40
Immobilization of Functional Biological Materials using Drop on Demand Ink Jet Printing for Sensor Development.
Jan L. Sumerel 1 , Leila Deravi 2 , David Wright 2
1 , Dimatix, Inc., Santa Clara, California, United States, 2 Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
Show AbstractIn contrast to thermal ink jetting that uses heat to generate fluid drop ejection from a nozzle, MEMS-constructed piezoelectric ink jet printheads use a thin PZT slab bonded to a silicon diaphragm to generate acoustic energy that drives drop formation without heat. This novel, non-contact, and nondestructive printing process immobilizes a variety of biological materials while retaining their biological activity; furthermore, this new processing technology can be used for sensor development. By formulating an ink and determining its jetting parameters, drop on demand immobilization of a variety of biological functional materials can be established for one-sided deposition. We have formulated a variety of bioinks for the printing of DNA, peptides and proteins using both direct inking and scaffold carriers for the immobilization of nucleic acids and antibodies. After the printing is completed, these molecular recognition elements remain functional and bind their complimentary oligonucleotides or their cognizant protein, respectively, from complex samples indicating that their biological activity is retained during the processing step. Moreover, competition studies with free peptide antigen or oligonucleotide complement demonstrates specificity. We have demonstrated the strength and utility of this drop on demand technique to print two sensor components, and further directions will be to integrate these additive processes and couple them to environmental detection.
9:00 PM - E12.41
Plasma Surface Functionalization of Poly[bis(2,2,2-trifluoroethoxy)phosphazene]
Lee Steely 1 , Harry Allcock 1 , Seong Kim 2 , Jeong Kim 2 3 , Bang-Kwon Kang 3
1 Chemistry, Pennsylvania State Univeristy, University Park, Pennsylvania, United States, 2 Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States, 3 , Atmospheric Process Plasma, Suwon Korea (the Republic of)
Show Abstract9:00 PM - E12.42
An Organic Electronic Ion Pump for Spatial and Temporal Control of Ion Delivery From a Surface.
Joakim Isaksson 1 , David Nilsson 2 , Peter Kjäll 3 , Nathaniel Robinson 1 , Agneta Richter-Dahlfors 3 , Magnus Berggren 1
1 Dept of Science and Technology, Linkopings Universitet, Norrkoping Sweden, 2 , Acreo AB, Norrkoping Sweden, 3 Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm Sweden
Show Abstract9:00 PM - E12.43
Enhanced thermal Properties and Gas Barrier Property of PMMA Nanocomposites with Layered Silicate via Soap-Free Emulsion Polymerization
Hsiu-Yu Cheng 1 , Guang-Way Jang 1 , George Jiang 2
1 Nanomaterial Department, Industrial Technology Research Institute, Hsinchu Taiwan, 2 Department of Chemistry, Chung Yuan Christian University, Chung Li Taiwan
Show Abstract9:00 PM - E12.5
Surface Stress Generation During Formation of Alkanethiol Self-assembled Monolayer (SAM).
Kanaga Karuppiah Kanaga Subramanian 1 , Ruqin Zhang 1 , Pranav Shrotriya 1 , Abhijit Chandra 1 , Sriram Sundararajan 1
1 Mechanical Engineering, Iowa State University, Ames, Iowa, United States
Show AbstractMicro-machined cantilevers coated with self-assembled monolayers (SAM) of alkanethiols are being utilized as sensing elements for new generation of high-sensitivity chemical and biological sensors. Presence of chemical species is detected by resolving the surface stress change associated with absorption/adsorption of analyte molecules on the sensitized cantilever. Challenges to widespread use of micromechanical cantilever sensors are: susceptibility to vibrations, integration in a single device and understanding the mechanism governing surface stress generation. We aim to overcome these limitations by developing a novel sensing approach based on high-resolution curvature interferometry (Kim et al, 2003) reinforced with multi-scale models of surface stress generation. In order to demonstrate the feasibility of our approach, we investigated the development of surface stress during the formation of self-assembled-monolayers (SAM) of alkanethiols on a gold-coated cleaved mica strip. A multi-scale model is developed to predict the surface stress generated during absorption of the alkanethiols on a gold film to understand the molecular mechanism underlying the surface stress generation. Atomistic simulations are performed to investigate the formation of self-assembled monolayers of Dodecanethiol on Au(111) surface. The results of the molecular simulations are incorporated into the multi-scale framework to understand the surface stress generation and curvature change observed during experiments at continuum scale.
9:00 PM - E12.6
Nanopatterning using Molecular Ruler Resists.
Charan Srinivasan 1 , Mary Anderson 2 , James Hohman 2 , Paul Weiss 2 , Mark Horn 1
1 Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States, 2 Departments of Chemistry and Physics, Pennsylvania State University, University Park, Pennsylvania, United States
Show Abstract9:00 PM - E12.7
Synthetic Growth of Fullerene-like CPx: First Principles Calculations.
Gueorgui Gueorguiev 1 , Andrej Furlan 1 , Hans Högberg 1 , Sven Stafström 1 , Lars Hultman 1
1 Department for Physics, Chemistry and Biology, Linköping University, Linköping Sweden
Show Abstract9:00 PM - E12.8
Tunneling Study of Organic-Inorganic Interfaces in Molecular Junctions.
Xiaohang Zhang 1 , Stephen McGill 1 , Peng Xiong 1
1 Physics & MARTECH, Florida State University, Tallahassee, Florida, United States
Show AbstractWe have studied the electron transport in planar tunneling junctions with aluminum oxide and an organic self-assembled monolayer (SAM) as the tunnel barrier. The general structure of the junctions is Al/AlO
x/SAM/Au with a junction area of ~ 0.4 mm
2. The organic molecules investigated include mercaptohexadecanoic acid (MHA), hexadecanoic acid (HDA), and octadecyltrichlorosilane (OTS); all of which form ordered SAMs on top of aluminum oxide. The use of a superconducting electrode (Al) enables us to determine unambiguously that these are high-quality tunnel junctions. Inelastic tunneling spectroscopy (IETS) has also been performed to verify the presence of a monolayer. For junctions incorporating MHA, the transport behavior is found to be strongly humidity dependent. The resistance of these junctions drops more than 50% when placed in dry nitrogen and recovers when returned into the ambient. The same drop also occurs when the sample is placed into a vacuum, and backfilling the vacuum with either dry N
2 or O
2 has negligible effect on the resistance. For comparison, junctions with HDA show the same humidity dependence, while OTS samples show much weaker dependence. Since both MHA and HDA have carboxylic groups and OTS does not, the results suggest that water molecules at the AlO
x/COO
- interface play a central role in the observed behavior. We investigate the possibility of a small increase in the tunneling length caused by water absorption using an approximation derived by Simmons
1. Furthermore, we use spin-polarized tunneling to look for possible magnetism
2 at the thiol-gold interface. This work was supported by a FSU Research Foundation PEG grant and NSF NIRT ECS-0210332.
1. John G. Simmons, J. App. Phys. 34, 1793 (1963)
2. I. Carmeli, et. al. J. Chem. Phys. 118, 10372 (2006)
9:00 PM - E12.9
Liquid Crystal Deposition on Poled, Single Crystalline Lithium Niobate.
Satyaveda Bharath 1 , Kaustubh Pimputkar 1 , Alex Pronschinske 1 , Thomas Pearl 1
1 Department of Physics, North Carolina State University, Raleigh, North Carolina, United States
Show Abstract