Symposium Organizers
Elisabetta Comini Universita' di Brescia
Pelagia Irene Gouma State University of New York-Stony Brook
Vincenzo Guidi University of Ferrara
David Kubinski Ford Motor Company
R1: Hybrids Materials and Detectors
Session Chairs
Tuesday PM, April 18, 2006
Room 3022 (Moscone West)
9:30 AM - **R1.1
Bio-Hybrid Materials for Immunoassay-Based Sensing.
Jonathan Fang 1 , Esther Lan 1 , Jing Zhou 1 , Bruce Dunn 1
1 Department of Materials Science and Engineering, University of California-Los Angeles, Los Angeles, California, United States
Show AbstractThe flexible solution chemistry of the sol-gel process has been used to synthesize nanostructured materials based on the encapsulation of biomolecules in a transparent, inorganic matrix. The resulting bio-hybrid material possesses two phases: a network of solid colloidal particles arranged with interpenetrating mesoporosity and a continuous solvent phase. It is now well established that the dopant biomolecules are immobilized in the mesoporous network and become part of the nanostructured architecture of the material. In nearly all cases, the dopant biomolecules retain their spectroscopic properties and biological activity. The resulting bio-hybrid materials have been widely explored as sensors with the biomolecule serving as both the biorecognition and transduction elements while the transparency of the matrix enables spectroscopic monitoring of the reactions.In this presentation we review our research directed at developing bio-hybrid based immunoassay approaches. We focus on the detection of cortisol, a steroid hormone released in the body at elevated levels in response to stress, which has become one of the principal biomarkers for monitoring astronaut health. We have developed a thin film optical biosensor for cortisol that was designed as part of a compact bioassay system for on-orbit monitoring and requires minimal liquid handling. The analysis is based on a competitive immunoassay in which cortisol antibodies are encapsulated in the sol-gel matrix. Well-defined calibration curves were obtained and the method of standard additions was used to determine quantitatively the cortisol concentration in human serum samples. The accuracy of the bio-hybrid immunoassay was demonstrated by the close correlation between the values from the bio-hybrid detector and those obtained using traditional immuno-binding techniques. In addition to cortisol, we will also present some of our recent immunoassay results involving the detection of peptides.
10:00 AM - R1.2
Biomimetic Nanotechnology: Structural Stability of Polypeptide Nanofilms.
Bingyun Li 1 , Donald Haynie 2
1 Orthopaedics, West Virginia University School of Medicine, Morgantown, West Virginia, United States, 2 Biomedical Engineering and Physics, Louisiana Tech University, Ruston, Louisiana, United States
Show AbstractSelf-assembly of designed polypeptides is a promising area of biomaterials research and development. We have prepared polypeptide nanofilms by electrostatic layer-by-layer self-assembly of cysteine-containing 32mers. We have studied the structural stability of the films by subjecting them to various extreme physical and chemical conditions. The results suggest that the film structure is very stable in organic solvent and, when dehydrated, at extreme temperatures. Such stability is in marked contrast to the behavior of proteins, which tend to denature under comparable conditions. Similar to proteins, polypeptide nanofilms cross-linked by disulfide bonds are considerably stronger than films stabilized by electrostatic, van der Waals, or hydrophobic interactions alone. These results provide further information on self-assembly of polypeptides which are a promising class of polyelectrolytes for the creation of nanofilms for biotechnology and biomedicine applications.
10:15 AM - R1.3
The Neurochip: An Advanced Nanomaterial for Small Molecule Capture of Biomolecule Binding Partners
Amit Vaish 1 4 , Mitchell Shuster 2 , Paul Weiss 3 2 1 , Michael Pishko 4 1 3 , Anne Andrews 6 1 3
1 Huck Institute of Life Sceince, Penn State University, State College, Pennsylvania, United States, 4 Chemical Engineering, Penn State University, State College, Pennsylvania, United States, 2 Physics, Penn State University, State College, Pennsylvania, United States, 3 Chemistry, Penn State University, State College, Pennsylvania, United States, 6 Veterinary Science, Penn State University, State College, Pennsylvania, United States
Show AbstractWe have developed coupling chemistries to tether the prototype small molecule neurotransmitter serotonin and its carboxylated precursor, 5-hydroxytryptophan, to “insertion-directed” self-assembled monolayers on Au surfaces thus achieving dilute, non-phase separated ligand coverage. Coupling chemistries are verified by grazing angle FT-IR. Nonspecific binding has been largely eliminated by surrounding the tethered ligands with oligoethylene glycols. Good specificity of the surfaces has been demonstrated by quartz crystal microbalance measurements of specific antibody recognition of serotonin-functionalized surfaces and serotonin membrane receptor recognition of 5-hydroxytryptophan surfaces, the latter mimicking free solution bio-recognition of serotonin. “Neurochip” materials will be used to screen for nucleic acid aptamers, which will be utilized as molecular recognition elements in the construction of novel nanosensors for in vivo neurotransmitter sensing.
10:30 AM - R1.4
Biocompatible poly(magnesium acrylate) Micro-pomegranates for Enzyme Immobilization.
Enrique Lopez_Cabarcos 1 , Jorge Retama 1 , Alejandro Castillo 1 , Beatriz Ruiz 2
1 Physical Chemistry II, Complutense University, Madrid Spain, 2 Analytical Chemistry , Complutense University, Madrid Spain
Show Abstract10:45 AM - R1.5
Anomalous pH Actuation of a Chitosan/SWNT Microfiber Hydrogel with Improved Mechanical Property
S. R. Shin 1 , S. J. Park 1 , S. G. Yoon 1 , C. K. Lee 1 , K. M. Shin 1 , M. K. Shin 1 , B. K. Gu 1 , M. S. Kim 1 , Y. J. Kim 1 , S. J. Kim 1
1 Dept. of Biomedical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractSoft biological microactuators using pH-sensitive hydrogels have been studied for developing microactuation or biosensors systems. The actuators undergo a reversible change in volume that results in a dramatic dimensional swelling and shrinking on exposure to and removal of an external pH stimulus. Chitosan is candidate for soft biological microactuator because it is biocompatible natural polymer and swells in acidic media due to the protonation of the amino groups. However, the mechanical properties of chitosan hydrogels are rather poor for microactuator. So the single-wall carbon nanotubes (SWNTs) have been used to reinforce the biocompatible polymer chitosan. In this work, composite microfibers composed of chitosan and SWNTs have been fabricated with a wet spinning method. The dispersion was improved by sonic agitation of SWNTs in a chitosan solution and then centrifugation to remove tube aggregates. Raman spectroscopy was used to measure the SWNTs state in solution, the form of the microfibers. The average diameter of the microfibers is 80–130 μm and has a smooth, uniform, striated surface. The mechanical behavior was investigated with dynamic mechanical analysis (DMA). Mechanical testing showed a dramatic increase in Young’s modulus for the chitosan/SWNTs composite fibers fabricated using the improved dispersion method. The wet mechanical properties were also improved by addition of SWNTs while the pH sensitivity of the microfibers was largely unchanged. The strain on the microfibers was determined from tensile load measurements during pH switching in acidic or basic electrolyte solutions. The microfibers showed a general actuation behavior of expanding at pH = 2 and contracting at pH = 7 under low tensile loads. However, the reverse actuation behavior was exhibited under high tensile loads. This anomalous pH actuation is both new and surprising. It can be explained from analysis of the differences in sample stiffness and Poisson’s ratio under tensile load in electrolyte solutions with different pH values.
11:30 AM - **R1.6
Intercalative Organic/MoO3 Nanohybrids for the detection of VOCs
Ichiro Matsubara 1 , Tohio Itoh 1 , Junzhong Wang 1 , Woosuck Shin 1 , Noriya Izu 1 , Norimitsu Murayama 1
1 , National Institute of Advanced Industrial Science & Technology (AIST), Nagoya Japan
Show AbstractWe have proposed intercalative type organic-inorganic hybrid materials as gas sensors for selective detection of volatile organic compounds (VOCs). The organic and inorganic components take part in molecular recognition and transduction of chemical signals to measurable resistance changes, respectively. We have prepared intercalative organic/MoO3 hybrid materials with a layered structure. The thin films of Polypyrrole intercalated ((PPy)xMoO3) hybrid exhibit a distinct response to formaldehyde and acetaldehyde gases by increasing in their electrical resistivity, which could be induced by the incorporation of VOC molecules into the interlayers. On the other hand, polystylene intercalated MoO3 hybrid shows the resistance decreasing response to acetaldehyde gas. The two types of hybrid materials show the different response to VOCs, indicating that the VOC gas responsibility could be controlled by the organic component.
12:00 PM - R1.7
Stem Cell Impregnated Carbon Nanofibers/Nanotubes for Healing Damaged Neural Tissue.
Jong Eun Lee 3 , Jong Youl Kim 3 , Dongwoo Khang 4 , Thomas Webster 1 2
3 Anatomy, Yonsei University, Seoul Korea (the Republic of), 4 Physics, Purdue University, West Lafayette, Indiana, United States, 1 Biomedical Engineering, Purdue University, Lafayette, Indiana, United States, 2 Materials Engineering, Purdue University, West Lafayette, Indiana, United States
Show AbstractDue to their electrical and geometric properties similar to constituent components of neural tissue, carbon nanofibers/nanotubes are intriguing materials for neural tissue engineering applications. For this purpose, the objective of the present collection of studies was to determine functions of neural cells (including neurons, astrocytes (cells that contribute to detrimental glial scar tissue formation), and neural stem cells) on carbon nanofibers/nanotubes. In vitro results highlighted increased functions of neural stem cells and neurons while at the same time decreased functions of astrocytes on carbon nanofibers compared to currently implanted electrode materials. Moreover, directed axonal extension from neurons was achieved in vitro along aligned carbon nanofiber/nanotube patterns created on polymer surfaces. Lastly, due to promising in vitro data, carbon nanofibers/nanotubes impregnated with stem cells were implanted into rat brains which possessed damage (i.e., a transient focal ischemia). Specifically, middle cerebral artery occlusions (MCAO) were created in rat brains by using a well established left intraluminal vascular occlusion procedure for 60 minutes. At that time, stem cells placed into carbon nanofibers/nanotubes were implanted into the damaged neural tissue for up to 8 weeks. After the end of the prescribed time periods, healing of damaged neural tissue was measured from histological sections and T2 weighted magnetic resonance (MR) imaging. Importantly, histology pictures demonstrated the differentiation of stem cells around the implanted carbon nanofibers/nanotubes into neurons which reestablished neural activity in the damaged area of the rat cerebral cortex. Such data highlights the promise carbon nanofibers/nanotubes have in healing brain damage that may occur due to a number of pathological situations (such as stroke, Parkinson’s disease, Huntington’s disease, etc.).
12:15 PM - R1.8
Enhancement of Antibody Binding on SiO2 Love Wave Sensor Surface using (3-glycidoxypropyl)trimethoxysilane.
Nicolas Moll 1 , Duy Hai Dinh 1 2 , Emilie Pascal 1 3 , Corinne Dejous 1 , Jean-Paul Pillot 2 , Bernard Benneteau 2 , Dominique Rebiere 1 , Daniel Moynet 3 , Djavad Mossalayi 3 , Jacques Pistre 1
1 , Laboratoire IXL, Talence France, 2 , Laboratoire de Chimie Organique et Organometallique, Talence France, 3 , Laboratoire d'Immunologie et de Parasitologie, Bordeaux France
Show Abstract12:30 PM - R1.9
Particle and Pore Size Dependence of Proteinase K Diffusion Through Sol-Gel Derived Silica.
Winny Dong 1 , Weijen Lin 2 , YiHsuan Lin 2 , Doja Elmatari 1 , Nicole Contreras 1 , Maria Torres 1 , Sheridan Vo 1
1 Chemical and Materials Engineering, California State Polytechnic University, Pomona, Pomona, California, United States, 2 Biological Sciences, Cal Poly Pomona, Pomona, California, United States
Show Abstract This study examines the influence of microscale particle size and nanoscale pore size on the diffusion of Proteinase K through sol-gel derived silica. The ability to control and predict the diffusion rates of enzyme through silica microparticles may be useful in designing controlled drug-delivery systems. Enzyme-doped silica gels were dried via supercritical drying (aerogels), low surface-tension solvent exchange (ambigels), and ambient evaporation of the water/alcohol byproducts (xerogels). This resulted in silica with three different microstructures and pore sizes: aerogels (pore diameter on the order of 20 nm), ambigels (20-50 nm), and xerogels (> 50 nm). Microparticles of the protein-doped silica were formed through grinding and the emulsion-method. Particle sizes tested were between 20 - 250 um. Silica xerogels, with the lowest overall porosity and largest pores showed the highest retention, highest amount of enzyme released, and the fastest release rates compared to silica aerogels and ambigels. The enzyme release rate is inversely proportional to particle size and directly proportional to incubation temperature. The emulsion method also showed better retention of enzyme compared to the ground samples. Recent data suggests that the microstructure of xerogels do a better job at stabilizing the enzyme than ambigels and aerogels.
12:45 PM - R1.10
Selective Detection of Chemical Warfare Agents Based on Semiconductor Metal Oxides and Polymer Coated Surface Acoustic Waves.
Chuncai Yang 1 , Guizhen Feng 1 , Brent Marquis 1
1 , Sensor Research and Development Corporation, Orono, Maine, United States
Show AbstractThe selectivity, sensitivity and repeatability/reproducibility of semiconductor metal oxides (SMOs) and polymer coated surface acoustic waves (P-SAWs) for the detection of chemical warfare agents (CWAs) will be reported. In general, the unmodified SMOs such as WO3, SnO2, and In2O3, etc. have high sensitivity and their detection limits can be up to 10 ppb toward CWAs, however, they lack selectivity to the detecting target on interfering environments. Our report will be focused on several novel types of SMOs and their hybrid sensing materials, which have significantly increased their selectivity toward the detecting target such as sulfur mustard simulent, 1,5-dichloropentane (DCP) and Nerve agents’ simulent, dimethyl methylphosphonate (DMMP) on existing interfering chemicals such as hexane, diesel, and methanol, etc. P-SAWs are another type of detecting technologies for CWAs detection, in this report, we will demonstrate how to make reproducible P-SAWs sensors (sensor to sensor and batch to batch), to decrease the baseline drift, and to increase the density of coated polymers on SAW surface for increasing their sensitivity (up to 300 KHz frequency change for 10ppm DMMP detection and with 100ppb detection limit to Sarin (GB) and VX) based on our developed novel polymers, surface reaction and surface assemble technologies.
R2: Biotechnology
Session Chairs
Bruce Dunn
Vincenzo Guidi
Tuesday PM, April 18, 2006
Room 3022 (Moscone West)
3:15 PM - R2.2
Electro-sculpting for Tissue and Organ Engineering.
Dong Han 1 , Pelagia Gouma 1
1 Materials Science and Engineering, Stony Brook University, The State University of New York, Stony Brook, New York, United States
Show Abstract3:30 PM - R2.3
The Use of Superparamagnetic Nanoparticles as Labels in Immunoassays.
Peter Hawkins 1 , Richard Luxton 1 , Janice Kiely 2 , Jasvant Badesha 1 , Patrick Wraith 2 , Jackie Barnett 1 , John Eveness 1
1 Faculty of Applied Sciences, University of the West of England, Bristol United Kingdom, 2 Faculty of Computing, Engineering and Mathematical Sciences, University of the West of England, Bristol United Kingdom
Show AbstractImmunoassays rely on the rapid and specific interaction between an antibody and its antigen (analyte)and have found many applications in such diverse areas as medical diagnosis, food quality assurance, environmental monitoring, agriculture and national defense. The assay is usually quantified via a label such as gold particles, enzymes or radioactive, fluorescent or chemiluminescent molecules attached to the antibody. In the well-known pregnancy test, the antibody labeled with blue, micrometer-sized latex particles reacts with the pregnancy hormone and the combination then produces a blue line when the antigen reacts with a line of immobilized secondary antibody. A recent development is the use of micro- and nanometer-sized magnetic particles (PMPs) as labels which have cores of a superparamagnetic material, coated usually with a polymer layer to which the antibody attaches via a linker molecule. We have used PMPs as labels in sandwich assays and the number of immobilized PMPs quantified using a resonant coil magnetometer (RCM) of our design. Techniques that have been developed by others to quantify the PMPs include magneto-resistive devices and magnetic induction. In one version of our device, secondary antibody is immobilized in a reaction surface on one side of a small ceramic chip with a flat spiral sensing coil of the RCM deposited using thick film technology immediately opposite on the other side. PMPs become immobilized in a sandwich assay on the reaction surface and their presence causes a decrease in the resonant frequency of the coil (from about 30MHz) that is directly related to the number of PMPs. We have found that the reaction times for assays are considerably reduced when an external magnetic field is used to pull the combined PMPs and antigen to the surface so that a reaction is more likely to occur. It is also unnecessary to remove excess PMPs because immobilized PMPs have a stronger effect on the RF field created by the sensing coil as their induced magnetic dipoles are also orientated in the external field whereas the directions of the induced dipoles in the unbound PMP are randomized by Brownian motion, and as the sensitivity of the sensing coil falls rapidly with distance, excess PMPs still in suspension also have less effect. We will report on our investigations into the magnetic properties of PMPs that give the best performance. Two or more analytes can be analyzed simultaneously and we have developed a system that measures the concentrations of the cardiac markers CRP and CKMB in whole blood in 4 minutes with no sample preparation. This work will lead to a simple bench-top or handheld device.The familiar pregnancy test is an example of a simple lateral flow device with a result that is either yes or no. We have adapted our system to a lateral flow format that gives a much wider quantitative range and have developed a device capable of measuring the concentrations of the prostate cancer marker PSA in plasma samples.
3:45 PM - R2.4
Quantitative Detection Using Porous Silicon Biosensors.
Huimin Ouyang 1 2 , Philippe Fauchet 1 2
1 Electrical and Computer Engineering, University of Rochester, Rochester, New York, United States, 2 Center for Future Health, University of Rochester, Rochester, New York, United States
Show Abstract4:30 PM - R2.5
GaN Nanowires: A New Material for Optical and Electrochemical Sensing of DNA.
Chinpei Chen 1 , Abhijit Ganguly 1 , Li-Chyong Chen 1 , Kuei-Hsien Chen 2
1 Center for Condensed Matter Science, National Taiwan University, Taipei Taiwan, 2 Institute of Atomic & Molecular Sciences, Academia Sinica, Taipei Taiwan
Show AbstractGroup-III nitride semiconductors are quite popular, especially, in optoelectronic application. In last few decades, tremendous interest has been aroused towards the growth and application of III-nitride materials, especially, in 1-D structure. Beside their unique optoelectronic properties, these nitride systems are also well known for their non-toxicity and biocompatibility, however their application in bio-world is truly ignored until date. On the other hand, in DNA-sensor application, search for a suitable transducer-material is still a big challenge. No single characterization technique is complete; and, for a better understanding of any material system, both optical and electrical techniques have been proved to be complementary to each other. This leads to a concept of a complete-sensor, and a promising bio-application of GaN, which may be the first transducer-material for DNA-sensor in both optics- and electronic-based sensor-application. In this report, single-stranded DNA (ss-DNA) molecules were immobilized on GaN nanowires (NWs) through covalent binding. The ss-DNA-immobilization on GaN NWs surface shows a huge change in electrochemical (EC) property, indicating an increase in impedance due to the surface-modification. On the other hand, GaN, a direct and wide band-gap material, shows a remarkable change in its emission properties (photoluminescence, PL) due to the change in surface-properties. Same DNA-GaN NWs system could be subjected to both PL and EC characterizations. Moreover, the interaction between ss-DNA, immobilized on GaN surface, and its complementary base-pairs can be observed, distinctly, by both PL and EC techniques. This fact that GaN is sensitive to the immobilization of DNA bases and can promote the formation of complementary base-pairs, leads to a possible biosensor based on GaN NWs.
4:45 PM - R2.6
Development of a Template-Directed Nanotube Array Gas Sensor Platform for Biosensing Applications
Kurt Benkstein 1 , Christopher Montgomery 1 , Richard Cavicchi 1 , Steve Semancik 1 , Michael Tarlov 1
1 Chemical Science & Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Show AbstractWhile Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) are known to be intra- and extra-cellular transducers in mammalian cells, the use of these molecules as biomarkers of cell response has been hindered by measurement difficulties associated with their low concentrations and the complex chemistry present upon release from cells. Toward the goal of measuring these potential biomarker molecules at the cell, we are developing a novel sensor platform to overcome the problems connected with the low concentrations and rapid reactivities of the target species. In order to achieve sufficient functionality to detect, for example, gas-phase NO in liquid media, a sensor platform must properly combine thin sensing films, nanoscale porous structure and compatible electrical contacts (i.e., compatible to both the active sensing material and the bio-active environment). This new conductometric sensor platform is based upon a porous nanotubular array membrane support structure. The large internal surface area realized for these nanostructured arrays serves as a template for thin metal oxide sensing films with enhanced sensitivity. Furthermore, the platform design facilitates incorporation of the sensor into the cell-growth medium, thus enabling proximal detection of ROS and RNS. In this presentation, we describe a research prototype that features an array of high-surface-area WO3 nanotubes (d = 200 nm, l = 60 μm) supported in an anodically etched alumina membrane, prepared via sol-gel chemistry. The nanotube arrays have been characterized electrically and by scanning electron microscopy and energy dispersive x-ray spectroscopy. Metal contact pads have been deposited at the top and bottom of the oxide-coated membrane to enable good electrical connection, while also permitting analyte diffusion into the pores of the sensor. Sensing experiments on volatile small molecules are also described to demonstrate the viability of the approach.
5:00 PM - R2.7
Gas-Sensor Cantilevers Synthesized from Ni-V-Zr Nanocomposites.
Reza Mohammadi 1 , Colin Ophus 2 , Larry Kostiuk 1 , Stephane Evoy 3 , Ken Westra 3 , Lee M. Fischer 3 , Yongliang Wang 4 , Velimir Radmilovic 4 , ZongHoon Lee 4 , Ulrich Dahmen 4 , David Mitlin 2
1 Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada, 2 Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada, 3 Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, 4 Lawrence Berkeley Lab, National Center for Electron Microscopy, University of California at Berkeley, Berkely, California, United States
Show AbstractWhile Ni films have been used in a variety of magnetic and MEMS devices, they have had limited applications in the area of cantilever-based sensing. Though having several advantages over insulators and semiconductors, metals are notoriously difficult to pattern or release due to their high stress state, large surface roughness and low strength. The aim of this work is to describe the mechanical properties, the microstructure, and the device applications of Ni-V-Zr ternary alloy nanocomposite thin films. We fabricated a range of compositions and microstructures by co-sputtering from Ni-V and pure Zr targets. Nanoindentation tests indicate that the hardness of the fabricated materials is significantly higher than that of conventional Ni-based films. In addition, Ni-V-Zr nanocomposites are under less stress and are almost an order of magnitude smoother compared to pure Ni or binary alloys. The properties of the nanocomposites are discussed in relation to the materials’ thin-film growth mechanism, grain size, crystal structure and grain orientation (we performed TEM, SEM, AFM and XRD analysis). As proof of principle, we synthesized free-standing functionalized nano-scale cantilevers, which have the potential to be used as gas sensors in harsh or elevated temperature environments.
5:15 PM - R2.8
Localized Surface Plasmon Biosensor Using Ag Nanostructured Films Fabricated by a Reduction Method.
Tomofumi Arai 1 , Penmetcha Kumar 2 , Koichi Awazu 1 , Junji Tominaga 1
1 Center for Applied Near-Field Optics Research (CAN-FOR), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Japan, 2 Functional Nucleic Acids Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Japan
Show AbstractThe phenomenon of localized surface plasmon resonance (LSPR) has been attracting much attention for a highly sensitive and label-free biosensing method. Recently, we have developed a novel fabrication method of Ag nanostructured films indicating a strong LSPR by the reduction of AgOx thin films using reactive ion etching [1]. This fabrication technique possesses several advantages over other methods as follows: (i) a uniformly Ag nanostructured surface is obtained on large area (> 100 cm2); (ii) no additional heating is required; and (iii) only several minutes are needed for the reduction of the AgOx, and these advantages enable a reliable mass production of nanostructured Ag films and indicate a large potential for providing cost-effective LSPR biosensors. AgOx thin films with a thickness of 50-100 nm were deposited by reactive rf sputtering on Si wafers. The deposited AgOx thin films were reduced to Ag using the reactive ion etching with a gas flow of CF4, O2 and H2 for about 1 minute as an initial etching process, and then with a gas flow of O2 and H2 for several minutes as a second etching process. From scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (TEM), it was found that Ag nanoparticles with a diameter of about 20 nm were formed during the initial etching, and the nanoparticles were developed into the nanostructures during the second etching. The reflectance spectra of the Ag nanostructured films showed a distinctly low reflectance around 390 nm in air due to the localized surface plasmon resonance of the Ag nanoparticles. The wavelength shift of LSPR for the Ag nanostructured films was found to show a linear dependence with a high correlation coefficient (>0.99) on the refractive index of the surrounding materials, which was conformed using different kind of solvents such as water (n=1.333), ethanol (n=1.361) or pyridine (n=1.508). Thus, the Ag nanostructured films can be applied to a LSPR biosensor which detects specific absorptions of a minute quantity of biomolecules on the surface of the Ag nanostructured films by monitoring the wavelength shift of the LSPR. Next, we investigated the ability of this LSPR biosensor for detecting the binding events between streptavidin and biotin molecules, which were immobilized at the surface of the Ag nanostructured films via Ag-thiol bonds. We have found that the LSPR biosensor has an ability to detect interactions at about 100 nM of streptavidin.[1] J. Tominaga, J. Phys.: Condens. Matter 15, R1101 (2003).
5:30 PM - R2.9
Studies on Biosensing Property and Functionalization of In2O3 and Carbon Nanotube Field Effect Transistor.
Chao Li 1 , Fumiaki Ishikawa 1 , Tao Tang 1 , Chongwu Zhou 1
1 , USC, Los Angeles, California, United States
Show AbstractBiosensors based on one-dimensional nanostructure materials, such as metal-oxide nanowires (NWs) and carbon nanotubes (CNTs), are attracting considerable attention due to their superior performance in terms of sensitivity, response time, and label free detection. Such sensors are expected as next disease diagnosing or drug screening tools, which are highly relevant to our ordinal life. In this context, we firstly inspected the biosensing properties of In2O3 NW and CNT field-effect transistors (FET) toward low-density lipoproteins (LDLs), an important marker to detect individuals at risk for cardiovascular disease. Complementary sensing responses between the NW and the CNT FET have been observed after exposure to LDLs particles, with the enhanced conductance for the NW and the reduced conductance for the CNT. Secondly, we performed the real-time prostate-specific antigen sensing, which is an oncological marker to detect the presence of the most frequently diagnosed cancer among men in the US, the prostate cancer. We observed selectivity from bovine serum albumin (BSA), and high sensitivity up to 5ng/ml with the NW and 50ng/ml with the CNT respectively. Finally, to implement dense arrays of nanosensors with multiple probe molecules, we studied the selective functionalizations of ITO films and In2O3 NWs with a DNA single strand by utilizing the electrochemical switching of the linker molecule between quinone and hydroquinone. The selective immobilization of the complementary DNA single strand via the DNA double strand formation, as confirmed by the fluorescence study, revealed the successful selective functionalization of ITO films and NWs.
5:45 PM - R2.10
Integrated Conducting Polymer Nanowire Devices for Biological Sensing Applications
Adelaja Arojuraye 1 , Shaun Filocamo 3 , Catherine Klapperich 1 2 , Mark Grinstaff 1 3 , Unlu Selim 4
1 Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States, 3 Department of Chemistry, Boston University, Boston, Massachusetts, United States, 2 Manufacturing Engineering, Boston University, Boston, Massachusetts, United States, 4 Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts, United States
Show AbstractWe have fabricated an integrated device incorporating micro and nanoscale components. The microscale structures were fabricated on semiconducting surface by patterning and depositing simple metal structures on silicon substrates. The structures include planar microscale electrodes separated by an insulating area. This structure allows the nanowires to be easily probed. Nanoscale wires were “written” on the microscale structures using AFM electrochemical dip pen nanolithography (e-DPN). The tip of the AFM is dipped into a solution of monomer, and then the tip is pulled along the surface while a potential is applied between the tip and surface. Wires less than 10nm thick and wide can be drawn 1-2 microns in length. Each wire can be precisely placed and lies between two electrodes. We have characterized these devices using imaging AFM and Raman spectroscopy. We have also made conductivity measurements. We have used these integrated devices to investigate the properties of polymer nanowires of polypyrrole, polyaniline, and poly(ethylenedioxythiophene). Additionally, we have conjugated the monomers used to fabricate the polymer nanowires with biotin. Wires fabricated from these monomers can bind avidin and streptavidin in solution. Conducting polymers conjugated with biological ligands have the potential to detect specific binding events to detect biological agents or pathogens or an array of environmental toxins. Optimization of processing techniques will allow for more precise measurements and provide a foundation for future integration of nano and micro scale technologies involving conducting polymers.
R3: Poster Session: Organic Materials for Sensing and Biotechnology
Session Chairs
Elisabetta Comini
Pelagia Gouma
Wednesday AM, April 19, 2006
Salons 8-15 (Marriott)
9:00 PM - R3.1
Molecularly Imprinted Polymers and Pathogens' Specific Binding and Detection.
Chuncai Yang 1
1 , Sensor Research and Development Corporation, Orono, Maine, United States
Show AbstractThe surface molecularly imprinted polymers (MIPs) for water-born pathogens’ specific binding and detection will be reported based on various synthetic methods. Among them, light initiated polymerization of acrylic monomers for MIPs is most efficient. Our experiments demonstrate that the composition of MIPs is critical for a bacterium’s specific binding on the imprinted recognition sites. The density and orientation of imprints play a major role on the pathogens’ binding efficiency. A novel approach on how to imprint, remove and bind pathogens on MIPs has been developed. The scanning electron microscope (SEM) has been used to study the surface imprinted recognition sites and the subsequent pathogens’ binding on them. The washing procedure and fluorescent optical microscope have been used to distinguish the specific binding of pathogens from non-specific binding of pathogens on MIPs and non-MIPs control polymers. The testing results from SEM and fluorescent optical microscope have clearly proved that the specific binding is different from the non-specific binding and the specific bound pathogens are sat on the impressions/imprinted sites. The study of repeatable binding on the same MIPs and the reproducibility (MIPs to MIPs, batch to batch) indicates that surface molecularly imprinted polymers for water-born pathogens’ specific binding is efficient and Biosensors (MIPs coated on quartz crystal microbalance (QCM)) based on MIPs are cheap, easy and robust.
9:00 PM - R3.10
Non-Aqueous Single Step Electrodeposition of Nanowires of Cadmium Zinc Telluride (CZT) for Radiation Sensing
Thulasidharan Gandhi 1 , Krishnan Raja 1 , Manoranjan Misra 1
1 Material Science and Metallurgical, University of Nevada, Reno, Reno, Nevada, United States
Show AbstractA single step non-aqueous electrodeposition process for synthesis of nanowires of CdZnTe (CZT) compound semiconductor has been developed. Using this process nanowires of CZT were grown on a self-ordered nanotubular titanium oxide template. Propylene carbonate was used as the non-aqueous medium. Composition and structure of the nanowires of CZT were characterized by scanning electron microscopy (FESEM), energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and optical absorption spectroscopy. The EDAX measurements showed Cd 0.96 Zn0.04 Te. XRD measurements proved the formation of compound CZT. The nanowires showed a band gap of around 1.7 eV. The electrical resistivity of the compound was greater than 10^9 ohm-cm. Further, to have a better understanding of the formation of ternary compound, different process parameters such as: bath temperature, deposition potential, pulse time and concentration of Cd/Zn ions are varied and the nanowire products are being characterized.
9:00 PM - R3.11
Self-Assembly Of Gold And Silver On Polystyrene-Polymethyl-Methacrylate Diblock Copolymers And Its Application To Surface Enhanced Raman Spectroscopy.
Alec Talin 1 , Blake Simmons 1 , Eric Majzoub 1 , Richard Anderson 1 , William Tong 2 , Zhiyong Li 2
1 , Sandia National Labs, Livermore, California, United States, 2 , HP Labs, Palo Alto, California, United States
Show AbstractWe investigate the growth of Au and Ag metals on PS-PMMA diblock copolymers and the application of the resulting metal-on-polymer films for Surface Enhanced Raman Spectroscopy (SERS). PS-PMMA self-assembles into a highly ordered morphology with feature dimensions in the tens of nanometers and geometries that include lamellae or hexagonally arranged cylinders of PMMA in a PS matrix. In our work we use these polymer surfaces as scaffolding for subsequent assembly of Au and Ag films. We find that evaporated Au self assembles into highly ordered patterns that closely match the underlying lamellae or hexagonal cylinder polymer morphology even up to a thickness of 20 nm. Ag, on the other hand, coalesces into islands with little apparent ordering. These differences translate into very distinct plasmon extinction and SERS characteristics for the metal-on-polymer films.
9:00 PM - R3.12
Carboxylated Carbon Nanotube assisted Hydroxyapatite Synthesis from Simulated Body Fluid.
Hak Yong Kim 1 , Santosh Aryal 2 , Shanta Bhattarai 2 , K.C. Remant 2 , P. Prabu 2 , N. Dharmaraj 3
1 Textile Engineering, Chonbuk National University, Chonju 561-756 Korea (the Republic of), 2 Bionanosystem Engineering, Chonbuk National University, Chonju 561-756 Korea (the Republic of), 3 Chemistry, Government Arts College, Udumalpet 642 126 India
Show Abstract9:00 PM - R3.13
Fabrication of Nanocomposites Using Highly Ordered Anodic Porous Alumina and Its Application to Ordered Arrays of Biomolecules
Masahiro Harada 1 , Futoshi Matsumoto 2 , Kazuyuki Nishio 1 2 , Hideki Masuda 1 2
1 Department of Applied Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo, Japan, 2 , Kanagawa Academy of Science and Technology, Sagamihara, Kanagawa, Japan
Show AbstractFabrication of ordered, fine structures of nanometer dimensions using anodic porous alumina, which has a naturally occurring ordered porous structure, has attracted growing interest for the development of several types of nanodevices. There have been many reports on the preparation of nanocomposites devices using anodic porous alumina as a host material. These nanocopsites device of porous alumina can be applied to the functional nanodevices, such as functional electrode array and high density arrays of functional biomolecules and so on. In this work, we describe fabrication processes of ordered metal disk arrays using highly ordered anodic porous alumina. The obtained ordered arrays of metals or semiconductors were applied for the preparation of functional nanodevices, such as nanodisk electrode arrays, or ordered arrays of biomaterials.
9:00 PM - R3.14
Redox Reactions of Bio Molecule for Nano-bio Battery
K. M. Shin 1 , S. J. Park 1 , S. G. Yoon 1 , C. K. Lee 1 , S. R. Shin 1 , B. K. Gu 1 , M. S. Kim 1 , M. K. Shin 1 , S. J. Kim 1
1 Dept. of Biomedical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractMetal oxide nanoparticles, the ferritin protein can act as an energy storage source in nano-bio batteries containing ferrous ferritin and a reconstituted ferritin cage with different inorganic elements, such as Co, Mn, Ni, and Pt. These were introduced as two ferritin half-cells with different redox potentials between the ferrous ferritin and the reconstituted ferritin. It is important to analyze the reduction and oxidation reactions of ferritin, because redox reactions are intimately involved in both the oxidation of Fe, which occurs during Fe storage, and the reduction of Fe, which is involved in Fe release. In vitro experiments have suggested that, once the core iron is reduced, the iron ions can exit the protein shell, and then can re-enter with phosphate ions. An understanding of ferritin redox reactions is an important component in elucidating the mechanism of iron loading and unloading.In this work, the reduction of ferritin analyzed in a solution composed of 3-[N-morpholino]propanesulfonic acid-buffered containing oxidized methyl viologen using cyclic voltammetry. Electrochemical analysis showed that oxidized methyl viologen was changed into reduced methyl viologen using an applied potential, and that the HoSF was reduced by the reduced methyl viologen formed. The reduction and oxidation peaks of the methyl viologen appeared at potentials around –700 and –600 mV, respectively, and the reduction and the oxidation peaks of the released Fe appeared at potentials around –300 and –100 mV, respectively. The reduction of HoSF was influenced by the pH of the ferritin solution and a pH = 7.5 ferritin solutions was optimum for reducing HoSF.
9:00 PM - R3.15
Quick and Sensitive Magnetic Separation of Oligonucleotide with Gold/Magnetic Iron-oxide Composite Nanoparticles
Takao Yamamoto 1 , Takuya Kinoshita 1 , Satoshi Seino 1 , Takashi Nakagawa 1 , Takefumi Doi 2 , Tomoko Takano 2 , Shinsaku Nakagawa 2 , Masakazu Furuta 3 , Noriyuki Ohnishi 4
1 , Graduate School of Engineering, Osaka University, Suita, Osaka, Japan, 2 , Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan, 3 , Graduate School of Science, Osaka Prefecture University, Sakai, Osaka, Japan, 4 , Magnabeat Inc, Ichihara, Chiba, Japan
Show AbstractWe have synthesized composite nanoparticles consisting of gold nanograins of a few nm immobilized on each substrate maghemite particle with an average diameter of 26 nm, and showed that these particles are useful for magnetic separation of functional biomolecules. We demonstrated that a target oligonucleotide was easily picked up from an aqueous solution by magnetically attracting these nanoparticels to which a probe oligonucleotide bonded. The probe was a thiol-modified oligonucleotide, 15-mer polythymine oligonucleotide, HS-5'-(T)15-3', and sulfur makes a firm bond with gold in the particles. The target oligonucleotide was 15-mer polyadenine oligonucleotide with a sequence complementary to the probe, which was labeled with fluoresceinisothiocyanate for detecting the targets magnetically retrieved, FITC-5'-(A)15-3'. Control experiments lacking for one of “gold grains”, “probe oligonucleotide” or “complementary sequence”, showed no fluorescence. We found that 0.75 nmol-oligonucleotide was picked up by 1-mg particles, and 15-30 minute was enough to saturate its amount. These nanoparticles were synthesized in an aqueous solution without using any detergent, and well dispersive in water. A reddish color of the dispersion, evidence of the occurrence of nanosized and dispersed gold grains, was observed with the naked eyes. The secondary particle size of the particles was 100 – 300 nm in water, and substantially no sedimentation occurs even after a day. The connection with the probe oligonucleotide was performed just by mixing two solutions at room temperature. This particle material should be a powerful tool for detecting a specific DNA/RNA sequence in vitro.
9:00 PM - R3.16
Application of Plasma Assisted Surface Technologies for the Construction of DNA and Protein Arrays.
Sanghak Yeo 1 , Changrok Choi 1 , Jaeyoung Yang 1 , Cheonmoon Park 1 , Heonyong Park 2 , Donggeun Jung 1
1 Physics, Sungkyunkwan university , suwon Korea (the Republic of), 2 molecular biology, Nanosensor and Biotechnology,, seoul Korea (the Republic of)
Show AbstractAbstractA plasma enhanced chemical vapor deposition (PECVD) method using plasma polymerized ethylenediamine (PPEDA) was employed to coat glass slides with amine functional groups. Fluorescein isothiocyanate (FITC) labeling indicated that the density of amine functional groups on these coated slides was affected by PECVD conditions, particularly deposition time. The PPEDA-coated slides were used for the development of DNA arrays. 5’-Amino-modified oligodeoxyribonucleotides (ODNs) and cDNA strands were immobilized onto PPEDA-coated slides and used for hybridization to labeled target strands.To immobilize proteins, plasma polymerized hexamethyldisiloxane (PPHMDSO) thin film was deposited onto the surface of glass slide. We modified PPHMDSO-coated glass slide by an additional oxygen plasma treatment with placing the patterned mask on the HMDSO-coated glass slide. Hydrophilic surfaces were detected by measuring the contact angle of water. Of great interest, proteins were strictly immobilized on the patterned O2 plasma treated areas, providing more efficient ways for fabricating the protein chips.These results demonstrate that PECVD and/or plasma surface treatment can be usefully used for the construction of DNA and protein arrays.
9:00 PM - R3.17
Sol-Gel Silica Films for DNA Microarray Applications
Kristjan Saal 1 2 , Margo Plaado 1 2 , Ilmar Kink 1 , Ants Kurg 1 3 , Uno Maeorg 1 2 , Ago Rinken 1 2 , Ants Lohmus 1
1 Lab. Of Low Temperatures, Institute of Physics, Tartu, Tatu, Estonia, 2 , Institute of Organic and Bioorganic Chemistry Tartu University, Tartu Estonia, 3 , Institute of Molecular and Cell Biology Estonian Biocentre, Tartu Estonia
Show Abstract9:00 PM - R3.18
Massive Assembly of Carbon Nanotube-Based Biosensor Arrays via “Surface-Programmed Assembly” Process.
Byung Yang Lee 1 , Jiwoon Im 1 , Minbaek Lee 1 , Dong Joon Lee 1 , Seunghun Hong 1
1 School of Physics and NANO Systems Institute, Seoul National University, Seoul Korea (the Republic of)
Show AbstractElectrical junctions based on carbon nanotubes (CNTs) have been drawing tremendous attention as highly-sensitive chemical or biological sensor components. However, a lack of reliable mass-production method for such junctions has been holding back their practical applications. One promising mass-production method for CNT-based junctions can be “surface-programmed assembly” process (Nature 425, 36 (2003)), where surface molecular patterns guide the ‘selective assembly’ and ‘precision alignment’ of carbon nanotubes on the substrate without using any external forces such as liquid flow, etc. Since this process does not require any high-temperature processing step, it can be applied to virtually general substrates. Using this method, we successfully demonstrated the fabrication of 256 x 256 carbon nanotube-based sensor arrays on both SiO2 and transparent thin glass substrates. Furthermore, by functionalizing the CNT junctions with enzyme L-glutamate oxidase, we demonstrated the selective detection of L-glutamate. Spectrophotometric analysis shows that the immobilized enzymes retain their activity after our process. AFM images show that enzymes are immobilized both in between and along the CNTs. These sensor arrays could be utilized in the field where the real-time detection of L-glutamate is needed such as in neurobiology or food industry.
9:00 PM - R3.19
A Laser Based, Solvent-free Technique for Depositing Functionalized Nanostructures.
Michael Papantonakis 1 , Eric Houser 1 4 , Chris Kendziora 1 , Erik Herz 2 , Ulrich Wiesner 2 , Richard Haglund 3 , Stephen Johnson 3 , R. McGill 1
1 Materials Science and Technology Division, US Naval Research Laboratory, Washington, District of Columbia, United States, 4 , Transportation Security Research & Development Laboratory, Atlantic City International Airport, New Jersey, United States, 2 Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 3 Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, United States
Show Abstract9:00 PM - R3.2
Fabrication of Biocompatible Nanocapsules by Mineralization of Polymer Nanocages with Calcium Phosphate.
Kris Perkin 1 , Jeffrey Turner 2 , Karen Wooley 2 , Stephen Mann 1
1 Centre for Organized Matter Chemistry, University of Bristol, Bristol United Kingdom, 2 Chemistry, Washington University in St Louis, St Louis, Missouri, United States
Show Abstract The formation of self-assembled core-shell structures with nanoscopic dimensions offers exciting applications in fields such as imaging and therapeutics. This study demonstrates that a class of these structures, polymer shell cross-linked nanocages (NC), may be coated with an ultra thin shell of calcium phosphate. This natural mineral gives the NC added robustness and biocompatibility. Fabrication of these structures was achieved by first forming micelles with the diblock copolymer poly(acrylic acid)-b-poly(isoprene) (PAA-b-PI). The PAA outer shell was 22% cross-linked using a diamino crosslinker leaving NC ~60nm in diameter as measured by light scattering, transmission electron microscopy and AFM. The carboxyl groups present in PAA were utilised to electrostatically sequester Ca2+ ions into the surface of the NC. Addition of HPO42- ions induced mineralization and various techniques (EDXA, FT-IR and SAED) established that the mineral formed was amorphous calcium phosphate. UV-vis studies followed the concentration of a drug, beta-carotene, being absorbed into the hydrophobic isoprene core and showed that the inorganic shell had a large effect on the permeability of the NC. Thus, the coated nanocages were shown to have promise as biocompatible nanocapsules for drug delivery applications.
9:00 PM - R3.20
Electrical Properties of DNA-Nanoparticle Networks Using Electric Force Microscopy Analysis
Yu-Jin Kim 1 , N. J. Lee 1 , J. S. Kim 2 , B. H. Nam 2 , Y. S. Kim 3 , C. J. Kang 1
1 Physics and Nano-Bio Research Center, Myongji University, Yongin, Gyonggido, Korea (the Republic of), 2 Biological Science and Nano-Bio Research Center, Myongji University, Yongin, Gyonggido, Korea (the Republic of), 3 Electrical Engineering and Nano-Bio Research Center, Myongji University, Yongin, Gyonggido, Korea (the Republic of)
Show AbstractThe electrical properties of DNA-nanoparticle networks constructed by the self-assembly of biotinylated DNAs and streptavidins(STVs) are investigated using the scanning probe microscopy. Firstly, we built mono-, di- and trivalently networked DNA structure through the ratio regulation of DNA and streptavidin complexes and then its local electrical property was measured. It is well known characteristics that the conformational change affects the electrical properties of DNA. So we treated the surface of the mica substrate with Ni2+ ion to give a mechanical compression to the deposited DNA. As ion concentration increases, physical height of DNA decreses due to the stronger interaction between DNA and the substrate and more supercoiled DNAs were found. This is caused by the compensation of negatively charged DNAs by the positve metal ions. In this talk, using spectroscopy and observed images, the results analysed on the local electrical properties of DNA-nano particle networks related to their structural and inter molecular configuration will be presented.
9:00 PM - R3.22
Hydrogen Detection Using Polyaniline Nanofibers
Shabnam Virji 2 , Bruce Weiller 2 , Richard Kaner 1
2 Materials Processing and Evaluation, The Aerospace Corporation, El Segundo, California, United States, 1 Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, United States
Show AbstractHydrogen is a clean energy source and sensors are needed for measuring the hydrogen concentration below the lower explosion limit in air of 4%. Polyaniline nanofibers are synthesized using a template-free rapid polymerization method. We have previously shown that the nanofibers respond well to a number of different gases including acids, bases, organic solvents, and redox active agents with resistance changes of over 8 orders of magnitude. Here we show that polyaniline nanofibers respond to hydrogen gas at room temperature with a small increase in conductivity. The suggested mechanism involves the dissociation of hydrogen and interaction with the amine nitrogen of the polyaniline chain. The response to hydrogen of doped and dedoped polyaniline nanofibers will be presented along with data on nanofiber composite films. The effect of humidity, oxygen, and deuterium on the sensor response will be presented and discussed in light of the proposed mechanism for hydrogen interaction with polyaniline nanofibers.
9:00 PM - R3.23
Self-assembled Porphyrin Nanostructures.
Roberto Paolesse 1 , Donato Monti 1 , Sara Nardis 1 , Corrado Di Natale 2 , Arnaldo D'Amico 2
1 Chemical Science and Technologies, University of Rome Tor Vergata, Rome Italy, 2 Electronic Engeenering, University of Rome tor Vergata, Rome Italy
Show Abstract9:00 PM - R3.24
Atomistic Study of Catalytic Growth of Carbon Nanotubes
Wei Xiao 1 , Mike Baskes 2 , Kyeongjae Cho 1
1 Mechanical Engineering, Stanford University, Stanford, California, United States, 2 , Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Show AbstractIn chemical vapor deposition (CVD) growth of carbon nanotubes (CNTs), metal nanoparticle catalysts are used as seeds for nanotube growth. During the CVD growth, hydrocarbon molecules (e.g., CH4) are catalytically reduced on the metal catalyst surface, and C atoms are deposited on the metal catalysts. This continuous supply of C atoms onto the catalyst nanoparticle over saturates the carbon in the metal and leads to a precipitation of a solid carbon structure on a part of the catalyst particle surface. Even though the research community generally knows these CVD growth processes of CNTs from metal nanoparticles, the detailed atomic processes during the CVD growth are not currently well understood. Specifically, the initial nanotube cap formation from the precipitation of oversaturated carbon in the metal nanoparticle is an important process to understand since the chirality of subsequently grown CNTs is determined from the initially formed cap structure. In this study, we have applied a modified embedded atom method (MEAM) potential to investigate the CNT growth from Ni nanoparticle catalysts. Carbon and Ni MEAM potential parameters and their cross potential parameters are carefully developed to simulate the growth process. Molecular dynamic simulations are used to examine the detailed atomistic processes of carbon nanotube growth from the Ni nanoparticle catalyst under diverse growth conditions.
9:00 PM - R3.25
Simple Detection of Binding Events Using an Anchoring Transition of Liquid Crystals on the Immobilized oligoDNAs.
Hak-Rin Kim 1 , Min-Geon Choi 1 , Joo-Eun Kim 1 , Jae-Hoon Kim 1 , Eui-Yul Choi 2 , Sang-Wook Oh 3
1 Department of Electronics and Computer Engineering, Hanyang University, Seoul Korea (the Republic of), 2 Central Research Institute of Boditech Inc. and Department of Genetic Engineering, Hallym University, Chunchon, Kangwon-Do Korea (the Republic of), 3 Department of Biology Education, Chonbuk National University, Jeonju, Jeonbuk Korea (the Republic of)
Show Abstract9:00 PM - R3.26
Patterning Substrate-templated Membrane Morphologies by Triton-X.
Nathanael Rosidi 2 , Michael Howland 1 , Annapoorna Sapuri-Butti 3 , Atul Parikh 3
2 Biomedical Engineering, University of California - Davis, Davis, California, United States, 1 Chemical Engineering, University of California - Davis, Davis, California, United States, 3 Applied Science, University of California - Davis, Davis, California, United States
Show Abstract9:00 PM - R3.27
Organic Semiconductor-based Flexible Thin-film Water Vapor Sensors for Real-time Monitoring of Plant Transpiration.
Satoshi Hoshino 1 , Manabu Yoshida 1 , Toshihide Kamata 1
1 Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki Japan
Show AbstractTo enable highly sensitive and real-time monitoring of plant transpiration directly from leaves, we have developed novel water vapor sensors, which are thin and flexible so as to make it possible to attach closely on the leaf surface. We employed microporous polymer membranes and a moisture sensitive polymer semiconductor with n-alkyl side-chain groups for the sensor fabrication. The thin and microporous film structure modified by adsorption of the polymer semiconductor provides a hydrophobic environment that prevents retention of the evaporated moisture inside and serves for efficient transport of the water vapor across the membrane. Thus the transpiration can be detected by the electrodes formed on the top surface of the sensor membrane through amperometry of the adsorbed moisture sensitive organic semiconductor. We confirmed that the sensor with an optimal device configuration showed a synchronous variation in output current around 10-10~10-9 A at 2 V for a change in the low-level transpiration rates ranging from 5 to 10 mmol/m2sec determined with a commercial transpiration meter (Delta-T Device AP-4 porometer), and enabled real-time monitoring of the transpiratinal variation. The sensor also had superior sensitivity to the porometer in regard to the measurement of the very low-level transpiration. We believe that these water vapor sensors, which have a suitable device configuration for low-cost and large-scale fabrication by printing technologies, will be useful for developing a transpiration monitoring system used in the field of precision agriculture based on irrigation control.
9:00 PM - R3.28
Polyaniline-Cellulose Acetate Hybrid System for Chemical Sensing
Aisha Bishop 1 , Elisabetta Comini 2 , Pelagia-Irene Gouma 1
1 Materials Science and Engineering, SUNY Stony Brook, Stony Brook, New York, United States, 2 Dept. of Chemistry & Physics, INFM Unita de ricerca di Brescia, Brescia Italy
Show AbstractLeucoemeraldine (LEB) is the reduced form of polyaniline (PANI) which has not been explored for sensing applications due to its insulating and unstable nature. Hybrid systems of LEB-PANI have shown to aid in the stability of the material yielding an active matrix for gas sensing. The electrospinning technique has been employed for preparation of PANI-cellulose acetate (CA) hybrid structures. Electrical resistance measurements reveal that the inherently insulating polymer matrix exhibits elevated conductivity upon exposure to NO2 and humidity and thus can serve as a candidate for NO2 and humidity sensing. This paper will address the sensing mechanism and stability of the PANI-CA film.
9:00 PM - R3.29
Sensitivity Enhancement of Reflective Interferometric Spectroscopy for Label-Free Biomolecular Detection
Jinghui Lu 1 , Tingjuan Gao 2 , Lewis Rothberg 2 1
1 Chemical Engineering, University of Rochester, Rochester, New York, United States, 2 Chemistry Department, University of Rochester, Rochester, New York, United States
Show AbstractState-of-the-art sensor devices, as efficient tools for disease diagnosis and prevention, environment monitoring, security investigation, food safety and so on, are in demanding needs and playing more and more significant roles in human life. We report a novel imaging technique with which we developed an advanced sensor for fast detection of label-free DNAs, RNAs, viral and bacterial pathogens qualitatively and quantitatively. Termed Reflective Interferometric Spectroscopy (RIS), our technique is based on removal of the destructive interference in the reflected intensity from an anti-reflection coated silicon substrate. Surface thickness variation that results from binding of target molecules can therefore be accurately measured. Our previous result demonstrated detection of short DNA oligonucleotides at femtomole-level. We recently improved the sensitivity of RIS so that as low as one Angstrom surface thickness change can be detected. In addition, using peptide nucleic acids (PNAs) as the sensing probe, we now can easily detect the complementary DNA targets at the amount of 10-fold less via signal amplification by gold nanoparticles.
9:00 PM - R3.3
Water-Soluble Dendritic Photosensitizers Capable of Multi-Photon Absorption and The Affects of Core Modification on Singlet Oxygen Generation.
Michael Oar 1 , William Dichtel 1 , Jason Serin 1 , Jean Frechet 1 , Tymish Ohulchanskyy 2 , Paras Prasad 2 , Joy Rogers 3 , Loon-Seng Tan 3
1 Department of Chemistry, University of California, Berkeley, California, United States, 2 Institute for Lasers, Photonics and Biophotonics, and Department of Chemistry, State University of New York, Buffalo, New York, United States, 3 Polymer Branch, Air Force Research Laboratory/MLBP, Wright-Patterson AFB, Ohio, United States
Show Abstract9:00 PM - R3.30
Modulation of Electronic Properties of Single Wall Carbon Nanotubes by the Presence of an Ionic Shell.
Vladimir Dobrokhotov 1 , Chris Berven 1
1 Physics, University of Idaho, Moscow, Idaho, United States
Show AbstractWe report the change to the band structure of two types of carbon nanotubes due to the presence of an isolated, non-conducting, uniformly charged shell held at a fixed distance above their surfaces. We find that, depending on the chirality of the nanotube, the strain on the lattice causes the dispersion relationships to change. This change can result in a modification of the band structure which can induce a metal-semiconductor transition. We consider these effects as a possible mechanism for heavy-metal ion sensing by functionalized carbon-nanotubes.
9:00 PM - R3.31
Materials used in Chemiblock Vapor Sensors
Douglas Schulz 1 , Aaron Halvorsen 1 , Conrad Thomas 1 , John Jacobson 1 , Jeremy Lee 1 , Aaron Reinholz 1 , Douglas Chrisey 1
1 Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, North Dakota, United States
Show AbstractThe first chemical gas transducers that employ NanoblockTM substrates are described. Sensor fabrication is realized by controlled deposition of a novel C black/polymer composite onto Si wafers with subsequent processing steps yielding transducers with a small form factor (<1x1 mm2). These so termed “Chemiblocks” are inexpensive (<$0.10 each), exhibit fast response times (i.e., t90 < 10 sec), rapid recovery times (t10 < 60 sec) and a lower detection limit of <50ppm when exposed to a nerve gas stimulant, dimethylmethylphosphonate. Application to array-based detection is anticipated to be straightforward given the maturity of conventional C-black/polymer composite sensor technology whereby differentiation between target analytes and interferents is well established. The novel chemoselective polymer composition of the transducer layer has been tailored for the detection of Improvised Explosive Devices (IEDs) and preliminary results will also be presented.
9:00 PM - R3.32
Fast and Quantitative Detection of Pathogens at Ultralow Concentration.
Jinhao Gao 1 , Lihua Li 1 , Kin-Hung Chow 2 , Ling Wang 1 , Pak-Leung Ho 2 , Bing Xu 1 3
1 Department of Chemistry, The Hong Kong Univ. Sci. & Technol., Kowloon Hong Kong, 2 Center of Infection and Department of Microbiology, The University of Hong Kong, Hong Kong Hong Kong, 3 Bioengineering Program, The Hong Kong Univ. Sci. & Technol., Kowloon Hong Kong
Show AbstractWe have reported the application of biofunctional magnetic nanoparticles (FePt-Van) for pathogen capture at ultralow concentration. Here we describe a simple protocol based on vancomycin and FITC conjugates (FITC-Van) for detecting bacteria by fluorescence. We combine two schemes: one is that FePt-Van conjugates capture bacteria at ultralow concentration by specific multiple ligand-receptor interactions; the other is the high sensitivity of the fluorescence spectra. In this procedure, we use excess amount of D-Ala-D-Ala to completely release FITC-Van from bacterial surfaces. Using the calibration curve generated from a series of known bacterial concentrations, we can quantitatively detect bacteria at the concentration as low as 10 CFU/mL within 2 hours. We expect that this simple system will find other applications in biologic researches and clinical diagnoses.
9:00 PM - R3.33
Anion Sensors in Polyurethane Matrices: Synergy Between Matrix and Sensor Materials Improves Selectivity of the Sensing Process.
Manuel Palacios 1 , Radek Pohl 1 , Grigory Zyryanov 1 , Pavel Anzenbacher 1
1 Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio, United States
Show AbstractThe significant role anions play in both the biological systems and industrial processes demands the development of highly sensitive and selective anion sensors capable of operating in various media, particularly in water. Numerous anion receptors and sensors utilizing hydrogen bonding have been synthesized. Hydrogen bonds, unlike electrostatic interactions, are directional and may be used to induce selectivity in an anion-sensor interaction. Unfortunately, hydrogen bonds are relatively weak, which makes reliable sensing in strongly competitive media such as water difficult in most of the real-life applications. The anion receptors and sensors utilizing stronger but non-directional electrostatic interactions are, however, plagued by low selectivity as all anions present in the medium are indiscriminately attracted to such receptors. Here we present materials utilizing synergy between a polymer matrix and simple sensor moieties. These materials consist of blends of hydrogen-bond-based colorimetric anion sensors (2,3-di(pyrrole-2-yl)quinoxaline, DPQ) with extended conjugated chromophores embedded in hydrophilic polyurethane matrices. Anion sensors embedded in the hydrophilic polyurethane matrix have the advantage of water being stripped off hydrated anions thus reducing or removing the competing hydrogen bonding from water. The resulting semi-wet sensors may use both the change in color and in fluorescence as a signal output. Specifically, multi-well micro-assays for small anions utilize a new family of polyurethane-embedded fluorescent sensors. These assays use 0.2 μL of aqueous analytes in each well and respond with a response time of <10s.In summary, the use of synergy between hydrophilic matrices and anion sensors for sensing of aqueous analytes allows for using simpler and less expensive receptors and opens up new possibilities for the development of high performance anion sensors with good selectivity and response profiles at a fraction of cost of most anion sensors.
9:00 PM - R3.5
Newly Developed Fe-Fe2O3/PolyoxocarbosilaneCore-Shell Nanocomposite Prepared by Laser Pyrolysis: Characterization and Sensing Properties.
Ion Morjan 1 , Josef Pola 2 , Rodica Alexandrescu 1 , Florian Dumitrache 1 , Adelina Tomescu 3 , Ruxandra Birjega 1 , Ion Voicu 1 , Lavinia Albu 1 , Anna Galikova 2 , Victor Ciupina 4 , Zdenek Bastl 5
1 Laboratory of Laser Photochemistry , National Institute for Lasers, Plasma and Radiation Physics, 76900 Bucharest Romania, 2 , Institute for chemical Process Fundamentals of the Czech Academy of Science, 165 02 Prague 6 Czech Republic, 3 , National Institute of Materials Physics, 077125 Bucharest Romania, 4 , Ovidius University, Constanta, P.O.B. 8600 Romania, 5 , J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech, 182 23 Prague 8 Czech Republic
Show AbstractNanocomposite metal/polymer systems, combining inorganic materials together with polymers in nanoparticle form are presently promising for a new generation of high temperature gas sensors. Sensing performances are dependent upon the nanoscale morphology. We report here about the preparation of nanosized iron-based particles that are covered with organosilicon polymer. The IR laser pyrolysis of the ethylene-sensitized iron pentacarbonyl and hexamethyldisiloxane gas mixtures was used as synthesis technique. The core-shell nanostructures become superficially oxidized to gamma-Fe2O3 in the outer core phase, through incomplete protection against the atmosphere by the porous structure of the surrounding polymer. For the measurements of phase-separated structures within the composites, the particles were characterized by different analytical techniques (spectral analyses, electron microscopy and thermal gravimetry). The sizes, shapes, chemical composition, internal structure and morphology of the nanoparticles depend on flow rates of precursors and total pressure of the procedure. Transmission electron microscopy images are compatible with crosslinked nanochains which appear together with ca 20-100 nm sized balls. The balls consist of dark cores and a lighter shell phase that can be respectively attributed to elemental iron and a blend of iron oxide and polyoxocarbosilane. The Fe-rich nanocomposite (which is poor in polyoxocarbosilane) has rather uniform size of nanochains, whereas the Fe-poor nanocomposite contains both nanochains and nanoballs of various sizes. The organosilicon polymer shell in the former contains less C-H bonds. Thermal behavior of composites is characterized by two-stage evolvement of methane. The sensing properties of the nanocomposites, were tested by depositing thick films on alumina substrates and heating them at 450 C. The variation of their electrical resistance in presence of CO and CH4 (in dry and humid air) was measured. Preliminary results address the selectivity of the new nanostructures relatively to the tested toxic gases.
9:00 PM - R3.6
Silicon Microchannel Array as a Basis of Biosensor Device.
Natalia Vandysheva 1 , Alexander Bublikov 1 , Sergei Romanov 1 , Dmitrii Pyshnyi 2 , Alexander Lomzov 2
1 , Institute of Semiconductor Physics Siberian Branch of Russian Academy of Sciences, Novosibirsk Russian Federation, 2 , Institute of Chemical Biology and Fundamental Medicine Siberian Branch of Russian Academy of Sciences, Novosibirsk Russian Federation
Show Abstract9:00 PM - R3.7
Nanostructures for Biosensors: Patterning of Surface-Enhanced Raman Spectroscopy-active Substrates.
Ivano Alessandri 1
1 , University of Brescia, Brescia Italy
Show Abstract9:00 PM - R3.8
Sysnthesis of Chitosan Hydrogel Containing Ionic liquid: Swelling and Penetrating of Ionic Liquid
C. K. Lee 1 , S. J. Park 1 , S. G. Yoon 1 , S. R. Shin 1 , K. M. Shin 1 , M. K. Shin 1 , B. K. Gu 1 , M. S. Kim 1 , S. J. Kim 1
1 Dept. of Biomedical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractThe swelling behavior of chitosan hydrogel in ionic liquid–water binary systems was studied using hydrophilic room-temperature ionic liquids (1-buthyl-3-methyimidazolium tetrafluorobrate, as donated BMI-BF4), to elucidate the swelling mechanism of chitosan hydrogels. The swelling of hydrogels is an important characteristic in their applications. Hydrogels show a large degree of swelling in aqueous environments, and a differential shirnk-swell response to different solvents, including organics and salt solutions. The most attractive field for hydrogels is in artificial muscles and actuators, because they provide a mechanical response to an electrical stimulation. Some hydrogels have been developed as polymer gel electrolytes for use in soft actuators, because hydrogels can be electrolytes themselves, and can also house an electrolyte by dissolving the electrolyte in the hydrogel network. However, hydrogel have a serious lack of electrical stability with regards to electrolytes in ambient conditions, caused by the high volatility of water. This means that there is limit to the application lifetime of hydrogels in polymeric conducting systems. Room-temperature ionic liquids (RTILs) are intersting liquid electrolytes for electrochemical applications. Major reasons for the interest in RTILs are their nonvolatility, high conductivity, and large electrochemical windows. Their nonvolatility diminishes the any risk to the electrical stability caused by loss of the solvent to the atmosphere. One aspect of RTILs is their ability to control water miscibility by simply changing the anion. Their utility in the field of polymer hydrogel electrolytes is not necessarily new. Thus, an understanding of the swelling behavior of hydrogel with a RTIL–water binary system is important for their application. In this study, we report on the preparation of a chitosan hydrogel containing an RTIL and on the elucidation of swelling mechanism of a chitosan hydrogel in an ionic liquid–water binary system. It was confirmed that chitosan hydrogels are much stiffer after immersing in a pure RTILs because the water existing inside the chitosan polymer network is extracted into the RTIL. The pH of the binary system changed when the RTIL was in contact with water. The chitosan hydrogels were fully dissociated at a 90% water content of the BMI-BF4–water binary system. The equilibrium binary system content behavior of the chitosan hydrogels depended upon the amount of free water, which is a measure of the number of water molecules that do not interact with the ionic liquid. Chitosan hydrogels containing the RTIL were prepared by dropping pure RTIL onto a fully water-swollen hydrogel.
9:00 PM - R3.9
Chemically Functionalized Nanopores for Bio-organism Detection.
Joakim Nilsson 1 , Sonia Letant 1
1 Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States
Show Abstract