William W. Yu Jilin University
Vicki L. Colvin Rice University
Quanqin Dai (In job transition)
Paul C. Howard U. S. Food & Drug Administration
GG1: Nanosafety I
Tuesday PM, November 29, 2011
Room 209 (Hynes)
2:30 PM - GG1.1
Multidentate Catechol-Derivatized Oligomers as Biocompatible Surface Cap for Iron Oxide Nanoparticles.
Hyon Bin Na 1 , Goutam Palui 1 , Xin Ji 1 , Hedi Mattoussi 1 Show Abstract
1 Department of Chemistry and Biochemistry , Florida State University, Tallahassee, Florida, United States
Iron oxide and metal-doped Iron oxide nanoparticles (NPs) exhibit unique size- and composition-dependent superparamagnetic properties, and they offer great promises for use in biomedical applications, including magnetic resonance imaging (MRI), magnetic separation and bioassays. High quality iron oxide NPs are prepared using high temperature reaction of organometallic precursors, and they are mainly hydrophobic and not compatible with biological systems. Surface processing is essential to render these NPs biocompatible and to further endow them with functionalities. Cap exchange with hydrophilic ligands is simple to implement, but relies on the use of commercially available short ligands, and these provide NPs with limited long term stability. It has recently been reported that single catechol-derivatized poly(ethylene glycol) (PEG) ligands exhibit high affinity to metal oxides NPs; this idea was inspired by the mechanism used by naturally occurring adhesive proteins in marine mussels such as L-3,4-dihydroxyphenylalanine (L-DOPA).We report the design and preparation of a new set of multidentate catechol-derivatized oligomeric ligands (OligoPEG-Dopa) that exhibit much stronger affinity to iron oxide nanocrystals than those presenting a single coordinating group. These ligands consist of a short oligomer backbone, several lateral dopamine anchoring groups, hydrophilic PEG segments, and a few reactive groups for further coupling to biological receptors. We found that rapid ligand exchange of hydrophobic iron oxide NPs with these ligands takes place and that the resulting nanoparticles were easily dispersed in buffer media with greatly enhanced colloidal stability over a broad pH range and in the presence of excess electrolytes. Furthermore, by inserting controllable fractions of azide-terminated PEG moieties the NPs become reactive to complementary alkyne functionalities via CLICK-driven chemistry; this opens up the possibility of effectively targeting such stable NPs towards biological receptors. We also measured the MRI contrast properties of these OligoPEG-capped iron oxide NPs and found that the relaxavities exhibit strong dependence on both concentration and size of the nanoparticles.
2:45 PM - **GG1.2
Multifunctional Oligomers for Enhancing the Biocompatibility of Semiconductor, Gold and Magnetic Nanocrystals.
Goutam Palui 1 , Hyon Bin Na 1 , Hedi Mattoussi 1 Show Abstract
1 Department of Chemistry and Biochemistry , Florida State University, Tallahassee, Florida, United States
Nanoparticles offer great promises as novel platforms for use in a variety of bio-inspired applications. Due some of their unique physical and chemical properties, these materials can advance our understanding of a variety of biological processes ranging from sensing, cellular and tissue imaging to drug delivery. Very often, post-synthetic surface modification is required to render these nanocrystals stable in aqueous media and biologically compatible. A sizable activity has centered on developing effective and reproducible strategies for preparing aggregate-free (monodispersed) hydrophilic and reactive platforms that are stable and compatible with common biological coupling chemistries. We have developed a few approaches based on covalent coupling and non-covalent self-assembly to conjugate various biomolecules to CdSe-ZnS core-shell QDs and Au nanoparticles (AuNPs). These nanocrystals were rendered water-soluble via cap exchange with polyethylene glycol (PEG)-based modular multidentate and multifunctional monomer and oligomer ligands. In this presentation, we will start with a description of the latest development in ligand design, characterization and capping strategies as applied to luminescent QDs, AuNPs, and magnetic nanocrystals. We then provide a few specific examples of such hybrid bioconjugates, and the use of those conjugates in sensor design based, for example, on charge transfer interactions. We will also describe a few examples where these conjugates are applied to probing specific biological processes in live cells.
3:15 PM - GG1.3
Safe Design of Engineered NanoParticles: Synthesis of Less Toxic Luminescent Quantum Dots.
Marielle Wouters 1 , Pascal Buskens 1 , Patrick Chin 1 , Frank Vercauteren 1 Show Abstract
1 , TNO, Eindhoven Netherlands
Nanomaterials display novel functional characteristics when compared to their bulk counterparts, and they offer widespread industrial possibilities. In the past years there has been growing activity in developing semiconductor nanoparticles, or quantum dots (QDs). Semiconductor nanoparticle properties differ from their bulk counterparts primarily due to changes in physical properties (size, shape, and specific surface area) and quantum confinement effects. The size-dependent properties of these QDs lead to a range of potential applications in optoelectronic devices, solar, cells, bio-labeling, etcetera.The safe use of engineered nanoparticles is of extreme importance in a growing market with new applications. Some state-of-the-art QD materials are designed on their functionality, and made from intrinsic toxic building blocks. In this contribution we will the first results obtained from a currently running project within TNO showing that we are able to design luminescent engineered nanoparticles that are potentially less toxic without losing their luminescent properties. In this contribution the whole chain of knowledge from synthesis to particle properties will be discussed. From the results it was concluded that properties can be designed and tuned without loss of functionality.
3:30 PM - **GG1.4
Phosphine-Free Synthesis of Metastable MnS and CuGaS2 Semiconductor Nanocrystals and Their Phase Transitions Induced by Pressure and Temperature.
Bo Zou 1 , Yingnan Wang 1 , Xinyi Yang 1 , Ningru Xiao 1 , Yongming Sui 1 Show Abstract
1 State Key Lab of Superhard Materials, Jilin University, Changchun China
Semiconductor nanocrystals, due to the pronounced influence of the size, shape, and crystalline phase on their electronic and optical properties, have been a popular topic in nanotechnology research over the past decade. Early developments in nanoscience and nanotechnology focused primarily on controlling the shape and size, particularly for semiconductor nanocrystals, to bring about previously unimaginable tunability of materials properties. After control of the size and shape of nanocrystals was mastered, the focus shifted to tuning the crystalline phase of nanomaterials, as these are known to alter material properties significantly, even in the macroscopic size regime. It is well known that variation of reaction temperature or pressure has been a preferred approach for nanocrystals phase transformation, which has been applied in many phase transformations of nanocrystals. While all of these studies enhance our understanding of nanocrystal phase transformations and afford new phase materials, efforts should be continued to study phase transformations in other nanocrystals for further advances in nanoscience. We have developed a facile method to synthesize zinc blende phase, wurtzite phase, and rock salt phase MnS semiconductor nanocrystals by one-pot solvent thermal approach. With this process, we have obtained the three phases with one synthesis procedure and observed the successive sequence of the process. Temperature played a greater role in the determination of the semiconductor nanocrystal phase. Accompanied by phase transitions, the shapes of MnS semiconductor nanocrystals were varied by simply changing the growth temperature. In addition, the synthesized zinc blende and wurtzite MnS semiconductor nanocrystals were both compressed in a symmetric diamond-anvil cell at room temperature and studied by in situ angle-dispersive synchrotron X-ray diffraction. We discovered that both phases directly convert to rock salt - MnS at 7 and 2.8 GPa, respectively. Moreover, nearly monodisperse CuGaS2 ternary nanorods were synthesized by one-pot approach. The X-ray diffraction pattern showed that the CuGaS2 nanorods were metastable wurtzite structure. The CuGaS2 ternary nanorods with wurtzite structure were reported rarely. The applications of high-pressure on wurtzite CuGaS2 nanorods were studied. The synchrotron XRD pattern indicated that the wurtzite CuGaS2 semiconductor nanocrystal transformed to chalcopyrite structure at 15.9 GPa. These have improved our fundamental understanding of phase stabilities in nano-materials.* Email: email@example.com Fax: +86-431-85168883ACKNOWLEDGMENTThis work was supported by NSFC (Nos. 21073071 and 20773043) and the National Basic Research Program of China (Nos. 2011CB808200 and 2007CB808000).
4:30 PM - GG1.5
Capping Ligand Protection of Core/Shell Quantum Dots: Theoretical Study.
Rodion Belosludov 1 , Hiroshi Mizuseki 1 , Atsuo Kasuya 2 , Yoshiyuki Kawazoe 1 Show Abstract
1 Institute for Materials Research, Tohoku University, Sendai, Miyagi, Japan, 2 Center for Interdisciplinary Research, Tohoku University, Sendai, Miyagi, Japan
Despite the remarkable progress in the photostability and bio-fictionalization of QDs, a large and important limitation of these nanomaterials still exists in their potential high cyclotoxicity . The common strategy for making QD bioconjugates includes both covering the semiconductor core structure by a shell of semiconductor material with a larger band gap followed by a bio cap using different functional molecules which improve the solubility of the QD and provide a specific target to anticancer agents. However, even in this case, cyclotoxicity, correlated with the liberation of free Cd2+ ions due to deterioration of the CdSe lattice, has been observed. The aim of this study is to gain an understanding of the structural morphology of the core as well as the inorganic/organic interface at the atomistic level using highly accurate first-principles calculations in an effort to improve upon the materials currently used in cancer diagnosis and to provide experimentalists with the necessary data for the actual realization of these nanomaterials. We investigated the effect of cap ligand binding on the stability of small CdSe as well as CdSe/ZnS nanoparticles. Both crystalline and fullerene-like CdSe-based structures have been used. These fullerene-like particles do not adopt the crystal form while resembling more closely carbon fullerenes and are remarkably stable . In the case of the substitution of the native TOP/TOPO with bifunctional ligands (“cap exchange” strategy), the mercaptoacetic acid (MAA), dithiothreitol (DTT), dihydrolipoic acid (DHLA) have been used. It is found that at low covering concentration, the MAA ligand is interacted not only through thiol but also through oxygen of an opposing carboxyl group which leads to parallel configuration of QD to surface. The same ligand configuration has been found in the case of DTT at low covering concentration. Using DHLA, it is possible to avoid interaction of carboxyl group with ZnS surface and hence to achieve better water-compatibility. Thus using the “cap exchange” strategy, it is important to increase carbon chain of ligand and also use the polydentate thiolated ligands, which is in agreement with experimental observation . The results also show that the interactions of these ligands with crystalline particles are stronger than with fullerene-like particles. This leads to a strong distortion of the core surface and in some cases, to decomposition of the crystalline nanoparticle. The effect of covering by polymerized silica shells has been also investigated. It has been found that the full thin covering of QDs can be easily achieved in the case of nanoparticles in comparison to the crystalline forms. Our results indicate that decreasing the size of the imaging agent can possibly lead to biologically inert coverings, making it possible to avoid cellular toxicity.REFERENCES1.X. Michalet et al. Science 307, 538-544.2.A. Kasuya et al., Nature Materials 3, 99-102, 2004.
4:45 PM - GG1.6
Inhibition of EGF-Induced Signal Transduction by Low Levels of Silver, Gold, and Iron Oxide Nanoparticles.
Kristen Comfort 1 , Elizabeth Maurer 1 , Laura Braydich-Stolle 1 , Saber Hussain 1 Show Abstract
1 , Air Force Research Laboratory, Wright Patterson Air Force Base, Wright-Patterson AFB, Ohio, United States
Three of the most prevalent nanomaterials to date are silver, gold, and iron oxide, each with numerous military, industrial, medical, and scientific applications. Extensive studies have addressed nanoparticle toxicity, however little research into the disturbance of biological mechanisms by nanomaterials at low levels has been conducted. These studies have, in general, demonstrated that nanomaterial exposure alters normal cellular behavior and responses to stimuli. Widespread exploration into the impact of nanomaterials on cellular processes, such as signal transduction, is crucial to fully elucidate any potential issues that may arise following chronic, basal exposure. The aim of this investigation was to ascertain to what extent metallic nanoparticles of similar size and morphology, but of different composition, altered epidermal growth factor (EGF)-dependent signal transduction in the human epithelial cell line A-431. Gold and super paramagnetic iron oxide nanoparticles were selected for this study due to their known biocompatibility and substantial use and promise in the medical field. Silver nanoparticles were also chosen to round out the experimental matrix with a well characterized, toxic, and commonly utilized nanomaterial.To evaluate nanoparticle interference in EGF signal transduction, we selected four essential points of the signaling response to investigate, as several potential sites exist for cellular disruption: 1) EGF-nanoparticle association, 2) Akt and Erk phosphorylation, 3) Akt activity, and 4) EGF-dependent gene regulation. Our results establish that 10 nm, spherical, silver, gold, and super paramagnetic iron oxide nanoparticles all disrupted the signaling response to EGF, but each through a unique mechanism. While low doses of nanoparticles appear to be biocompatible, based on cytotoxicity, we showed that alterations to cellular functions do occur on both a protein and genomic level. These findings raise the question of whether long term exposure may create functional defects, and call for further investigation into the impact of nanomaterials on biological processes.
5:00 PM - GG1.7
Toxicity of Planar and Nanosized GaP Surfaces under Different Environmental Conditions.
Albena Ivanisevic 1 Show Abstract
1 , NCSU, Raleigh, North Carolina, United States
Many III-V semiconductor materials have been widely investigated as planer substrates as well as nanoscopic entities in the forms of nanoparticles, wires and branching types of structures. The reason for the enormous interest in these materials is the great technological possibilities they offer due to their electrical and optical properties. Recently studies have shown that in terms of adapting these materials to biological applications such as in situ sensing and cell probing, GaP and GaN are the two materials that show favorable results in terms of biocompatibility by exhibiting no cytotoxicity in vitro. However, detailed in vivo studies have shown that uncoated GaP releases Ga in toxic concentrations, and one needs to develop methods to protect the surface from releasing this material. We investigate a novel surface functionalization scheme that protect GaP surfaces, test their long term stability in physiologically relevant conditions, and understand the molecular phenomena that govern their survival or deterioration under different environmental conditions. A stability study using azide-functionalized surfaces showed good stability in saline solutions with varying concentrations of H2O2. Inductively-coupled plasma mass spectrometry (ICP-MS) was used to evaluate the gallium concentration in the stability solutions. Each functionalization provided relatively equal suppression of gallium leaching.
5:15 PM - GG1.8
Zebrafish Embryo Toxicity of Ultrasmall Gold Nanoparticles.
Yu Pan-Bartneck 1 , Annika Leifert 2 , Ulrich Simon 2 , Dominic Laaf 1 , Michael Graf 1 , Willi Jahnen-Dechent 1 Show Abstract
1 Biomedical Engineering, Biointerface Laboratory, RWTH, Aachen Germany, 2 Inorganic Chemistry, RWTH, Aachen, NRW, Germany
We previously reported size dependent cytotoxicity of triphenylphosphine monosulfonate (TPPMS) capped gold nanoparticles (AuNPs). The 1.4nm TPPMS modified AuNPs induced oxidative stress and induced expression of heat shock protein (HSP70) in HeLa cells. Here we studied the influence of Au1.4MS on vertebrate development in zebrafish embryos. We tested the embryonic mortality and teratoginicity in the presence of Au1.4MS. 100% embryos died in the presence of 400 µM Au1.4MS. At sublethal concentrations, Au1.4MS induced developmental retardation, hypopigmentation and pericardial edema in the zebrafish embryos. Toxicity and teratogenicity were ameliorated by addition of sulfur containing reducing agents, glutathione, N-acetyl-cysteine and sodium thiosulfate. In contrast, TPPMS, a reducing agent without thiol groups did not decrease embryo toxicity at 72 hpf. However, toxicity was reduced at 24 hpf. While 100% of embryos died within 6 hours in response to 800 µM Au1.4MS, the addition of TPPMS let all the embryos survive until 24hpf. The fact that glutathione, N-acetyl-L-cysteine and sodium thiosulfate, but not TPPMS reduce toxicity of Au1.4MS suggested that thiol-containing compounds interfere with the molecular toxicity mechanism. We hypothesize that thiol-containing reductive agents will greatly influence ligand stability and therefore the ability of AuNPs to interact with biological targets. The binding of TPPMS phosphorus to the gold core is much weaker than GSH sulfur binding and thus TPPMS should be competitively replaced from the gold core of Au1.4MS after contact with GSH. This replacement reaction is likely to avoid the interaction between Au1.4MS and biological targets.
5:30 PM - GG1.9
Gold Nanoparticles Toxic Effects on Adipose Derived Stromal Cells.
Tatsiana Mironava 1 , Michael Hadjiargyrou 2 , Marcia Simon 3 , Miriam Rafailovich 1 Show Abstract
1 Materials Sciene and Engineering, State University of New York at Stony Brook, Stony Brook, New York, United States, 2 Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, New York, United States, 3 Oral Biology and Pathology, School of Dental Medicine, State University of New York at Stony Brook, Stony Brook, New York, United States
Gold nanoparticles can be easily functionalized which allows the production of new drugs with chemical groups that target cancer cells, and due to the high electron density of Au, allow for enhanced imaging. However, their potential health risk(s) and interactions with cells are not fully known. Many researchers brought forth the fact that such nanoparticles exhibit exotic physical properties that allow them to penetrate unusually deep into skin and other organs. However, most previous studies have focused determining the general proliferation or apoptosis levels for cells exposed to AuNPs, after relatively short exposures, less than 24 hours that might not be enough to reveal cellular impairment. The skin is the primary source of contact for nanoparticles, therefore, we chose to conduct our studies using different sizes of AuNPs 13 nm and 45 nm and Adipose Derived Stromal (ADS) cells. Our results indicates that nanoparticles induce cell damage in terms of cell proliferation, cell area, structural and extracellular matrix (ECM) protein expression and apoptosis, damage is a function of time, particle size and concentration. More specific, 13 nm AuNPs inhibit lipid accumulation by 45% and by 55% in case of 45 nm gold. Expression of adiponectin, the adipogenesis marker, is decreased in 40% and 45% after incubation for 2 weeks with 13 nm and 45 nm AuNPs respectively. Collagen is also reduced in 35% and 42% in cells cultured in presence of 13nm and 45 nm gold. The fibronectin/collagen ratio is altered which is normally associated with ECM hardening and aging. Cell recovery once the particles are removed was also investigated, cells were found to undergo almost full recovery as a function of time.
5:45 PM - GG1.10
Silica Induced Production of Inflammatory Mediators by Alveolar Macrophages: Particle Size and Surface Iron Effects on Lipid Peroxidation and Lipid Raft Disruption.
Gayatri Premasekharan 1 , Kennedy Nguyen 1 , Heather Jackson 1 , Henry Forman 1 2 , Valerie Leppert 1 Show Abstract
1 School of Engineering, University of California Merced, Merced, California, United States, 2 Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
During the past few years, research on toxicity of a variety of microscale and nanoscale materials has increased tremendously owing to their usage in a plethora of applications in medicine and technology. However, many questions still remain as to their toxicity, due to both the variety of materials properties that may lead to toxicity (such as phase, size, surface chemistry, contaminants, and agglomeration) and a lack of understanding of toxicity mechanisms at sub-lethal doses that would mimic a realistic exposure scenario. Since iron is a common contaminant on ambient and engineered micro/nanophases that has been shown to increase respiratory toxicity in some studies, we have hypothesized and subsequently investigated a unique mechanism for its role in micro- and nano-silica particle-mediated lipid peroxidation-dependent transcription of cytokines in macrophages under a low non-cytotoxic dose. We have found that at 1 µg/ml dose of silica the presence of iron and reduction of particle size significantly increases superoxide, lipid peroxidation, and cytokine production in macrophages. Addition of an iron chelator abrogates superoxide production and inhibits lipid peroxidation and cytokine induction, supporting the hypothesis that iron impurities increase the pro-inflammatory effects of nanophases on lung macrophages through superoxide production and subsequent lipid peroxidation. Furthermore, addition of a phosphatidylcholine-specific phospholipase C (PC-PLC) inhibitor, Tricychodecan-9-yl-xanthate, blocks cytokine production, suggesting that the production of cytokines occurs through a PC-PLC mediated mechanism.Our current work shows that the lipid peroxidation observed in macrophages upon silica exposure also causes reorganization of lipid rafts thereby affecting signaling, which has not been previously reported. Lipid rafts are large fraction subdomains of plasma membrane that are rich in cholesterol and glycosphingolipids and involved in the regulation of signal transduction. Specifically, the presence of iron impurities on silica particles was found to lead to disruption of lipid raft organization compared to particles without iron. Addition of an iron chelator negated this effect, supporting the conclusion that lipid raft disruption is involved in the production of cytokines through PC-PLC upon exposure of macrophages to iron-doped silica particles and subsequent superoxide production and lipid peroxidation. Increased understanding of the role of iron in and mechanism for particle-induced inflammation at sub-lethal doses should allow for better identification of important parameters to test for and control in therapeutic and diagnostic applications of micro- and nano-phases.
William W. Yu Jilin University
Vicki L. Colvin Rice University
Quanqin Dai (In job transition)
Paul C. Howard U. S. Food & Drug Administration
GG2: Nanosafety II
Wednesday AM, November 30, 2011
Room 209 (Hynes)
9:00 AM - **GG2.1
Potential Environmental Impact of Nanoparticles: A General Approach by the iCEINT Group.
Antoine Thill 1 4 , Mariane Planchon 1 4 , Olivier Spalla 1 4 , Mélanie Auffan 2 4 , Jérôme Rose 2 4 , Mathieu Therezien 3 4 , Jean-Yves Bottero 2 4 , Mark Wiesner 3 4 Show Abstract
1 DSM/IRAMIS, CEA, Gif sur Yvette France, 4 , iCEINT, www.i-ceint.org France, 2 CEREGE, CNRS, Aix en Provence France, 3 CEE, Duke University, Durham, North Carolina, United States
The specific properties of engineered nanoparticles (NPs) are being widely used, sometimes for years, in many fields such as medicine, cosmetic industry or electronics. Their increased production and use comes with environmental and safety concerns raised by the juxtaposition of a potential effects of these components on human health and natural environment and the lack of knowledge especially on their potential environmental concentrations and behavior.The main objective of the iCEINT (international Consortium for the Environmental Implication of Nanotechnology) is to respond to the challenge of relating a vast array of nanomaterial properties to their potential environmental exposure, biological effects, and ecological consequences. Rather than staying on case-by-case studies, our vision is to extract general principles from environmental pertinent examples that determine nanoparticles behavior and translate this knowledge into the language of risk assessment to provide guidance in addressing existing and future concerns surrounding the environmental implications of nanomaterials.Several examples have been already examined in detail. These examples and our perspectives will be presented. The case of CeO2 nanoparticles used as diesel exhaust catalyst or as additive in paints has been studied. The transformations of the CeO2 NPs and their impact on bacteria have been assessed. The case of TiO2 which is used as additive in sunscreen has also been examined as well as the degradation of the protective layers on the nanoTiO2 surface with respect to their potential production of Reactive Oxygen Species. Finally, the transfer of nanoparticles in natural water is considered and the development of models able to predict the behavior of nanoparticles is presented.
9:30 AM - **GG2.2
Relating the Physicochemical Characteristics of Nanomaterials to Their Biological Safety.
Vicki Stone 1 Show Abstract
1 School of Life Sciences, Heriot-Watt University, Edinburgh United Kingdom
Manmade or engineered nanomaterials are currently available a wide variety of compositions including metals, metal oxides, carbon, polymers and composites. In addition they vary with respect to a spectrum of physicochemical characteristics including size, surface area, shape, charge, crystal structure, solubility, strength and electrical conductivity. These characteristics are exploited to make new and interesting products, however the same properties that make these materials interesting to nanotechnology may also influence their biological reactivity and hence their toxicity. Toxicologists first became interested in nano-scale particles due to their role in driving the adverse health effects of particulate air pollution. This research indicates that particulate pollution is responsible for ill health and deaths involving both respiratory and cardiovascular diseases via activation of oxidative stress and inflammation (activation of the immune system) in susceptible individuals. This information is being used to investigate new nanomaterials, but instead of focusing on inhalation as a route of exposure, toxicologists also now need to consider ingestion, injection and dermal application as well as a wider range of potential targets for toxicity. Various different physicochemical characteristics have been demonstrated to impact on toxicity. For example, high aspect ratio nanoparticles, such as carbon nanotubes, that are long and straight have been shown to induce inflammation and changes to cells lining body cavities (mesothelial cells) that are similar to those induced by asbestos. Particles with a positively charged particles seem to be taken up by cells more effectively than neutral or negatively charged particles, leading to greater toxicity. This presentation will explore further different characteristics, how they can be investigated and their impact on the biological response envoked.
10:00 AM - GG2.3
Quantifying the Origin of Nanosilver Ions and Their Antibacterial Activity.
Georgios Sotiriou 1 , Andreas Meyer 2 , Jesper Knijnenburg 1 , Sven Panke 2 , Sotiris Pratsinis 1 Show Abstract
1 Particle Technology Laboratory, ETH Zurich, Zurich Switzerland, 2 Bioprocess Laboratory, ETH Zurich, Basel Switzerland
Nanosilver is one of the most prominent components in several nanotechnology products, primarily for its bactericidal and plasmonic properties [1,2]. Its use, however, is questioned as U.S. EPA has been petitioned to label it as pesticide. To better understand its antibacterial activity, nanosilver with closely controlled size immobilized on nanostructured silica is generated by flame aerosol technology . The antibacterial activity of small (<10 nm) nanosilver particles is attributed mostly to released Ag+ ions from their surface upon contact with water . The origin of these ions is explored systematically now by conditioning the surface of various nanosilver particles (4-9 nm) immobilized on nanostructured silica by wet-impregnation and dry flame-spray pyrolysis. Silica prevents nanosilver flocculation without the need of any surface functionalization (e.g. citrate) that would compromise the Ag+ ion release kinetics. Washing or reducing the Ag/SiO2 nanoparticles removes the oxide layer from the nanosilver surface minimizing their ion leaching. The amount of leached Ag+ ions corresponds to the dissolution of one or two silver oxide monolayers. Finally, the antibacterial activity of small (< 10 nm) nanosilver particles that have their surface oxide layer removed or reduced is significantly lower than the freshly prepared ones by either wet or dry methods.References Sotiriou, G. A. & Pratsinis, S. E. Antibacterial activity of nanosilver ions and particles. Environ. Sci. Technol. 44, 5649-5654 (2010). Sotiriou, G. A., Sannomiya, T., Teleki, A., Krumeich, F., Vörös, J. & Pratsinis, S. E. Non-toxic dry-coated nanosilver for plasmonic biosensors. Adv. Funct. Mater. 20, 4250-4257 (2010). Sotiriou, G. A., Teleki, A., Camenzind, A., Krumeich, F., Meyer, A., Panke, S. & Pratsinis, S. E. Nanosilver on nanostructured silica: Antibacterial activity and Ag surface area. Chem. Eng. J. 170, 547-554 (2011).
10:15 AM - GG2.4
Investigation of Cytotoxic Effects of Water Soluble Silver Nanoparticles on Tumor Cells.
Chunyan Wang 1 , Suresh Valiyaveettil 1 Show Abstract
1 Chemistry , National University of Singapore, Singapore Singapore
Metal nanoparticles (NPs) have been found in a wide range of commercially available consumer products ranging from cosmetics to household detergents. This is especially true for silver (Ag) NPs owing to antimicrobial properties. Recently, many approaches have been used for preparing Ag NPs, as they may reduce or eliminate the toxic effects towards the environment and ultimately to human being. In our study, we explore the synthesis of Ag NPs using plant extracts at room temperature. Our one-pot approach does not require additional surfactant, capping agent, reducing agent or template. The as-synthesized nanostructures were characterized using transmission electron microscopy and UV spectroscopy. The toxicity of Ag NPs with respective capping agents was studied using human cervical cancer cells (HeLa) and hepatocellular liver carcinoma cells (HepG2). Furthermore, the level of toxicity was evaluated using changes in cell morphology, cell viability and oxidative stress studies. In addition, we also demonstrate that toxicity of Ag NPs change dramatically with non-toxic capping agents.
11:00 AM - **GG2.5
Computational Nanotoxicology: Nano-QSAR for Predicting the Toxicity of Metal Oxide Nanoparticles.
Bakhtiyor Rasulev 1 , Tomasz Puzyn 1 4 , Agnieszka Gajewicz 1 4 , Xiaoke Hu 3 , Thabitha Dasari 3 , Andrea Michalkova 1 , Huey-min Hwang 3 , Andrey Toropov 5 , Danuta Leszczynska 2 , Jerzy Leszczynski 1 Show Abstract
1 Jackson State University, Department of Chemistry and Biochemistry, Interdisciplinary Nanotoxicity Center, Jackson, Mississippi, United States, 4 Laboratory of Environmental Chemometrics, University of Gdansk, Gdansk Poland, 3 Department of Biology, Jackson State Univeristy, Jackson, Mississippi, United States, 5 , Instituto di Ricerche Farmacologiche Mario Negri, Milano Italy, 2 Department of Civil and Environmental Engineering, Jackson State Univeristy, Jackson, Mississippi, United States
It is expected that the number and variety of engineered nanoparticles will increase rapidly over the next few years. A thorough understanding of the relationship between the physicochemical properties and the behavior of nanomaterials in biological systems is essential for developing new and safe nanomaterials, as well as predicting the potential toxicity of them. Certainly, there is a need for new methods to quickly test the toxicity of these materials. Because experimental evaluation of the safety of chemicals is expensive and time-consuming, computational methods have been found to be efficient alternatives for predicting the potential toxicity and environmental impact of new nanomaterials before mass production. Metal oxides are an important group of engineered nanoparticles, because they are widely used in cosmetics and sunscreens, self-cleaning coatings and textiles. Other applications include their use as water-treatment agents and as materials for solar batteries and more recent automobile catalytic converters. However, it has been shown recently that nanosized particles of these oxides (but not their macro or micro counterparts) are toxic to some organisms.We show that the quantitative structure–activity relationship (QSAR) method commonly used to predict the physicochemical properties of chemical compounds can be applied to predict the toxicity of various metal oxide nanoparticles. Here, we apply nano-QSAR to predict the toxicity of nanoparticles.Based on experimental testing, we have developed a model to describe the cytotoxicity of different types of metal oxide nanoparticles to bacteria Escherichia coli. The model reliably predicts the toxicity of all considered compounds, and the methodology is expected to provide guidance for the future design of safe nanomaterials. Based on this model and experimental data6, we have hypothesized the most probable mechanism for the cytotoxicity of these nanoparticles. Some other physico-chemical properties that depends on the size of nanoparticle also discussed.
11:30 AM - GG2.6
Examining the Effect of Surface Chemistry on the Toxicity of Silver Nanoparticles.
Yujie Xiong 1 2 Show Abstract
1 School of Chemistry and Materials Science, University of Science & Technology of China, Hefei Anhui China, 2 School of Engineering and Applied Science, Washington University in St. Louis, St. Louis, Saint Louis, Missouri, United States
Silver nanoparticles are widely used in antibacterial, plasmonic and electronic applications and hence it is imperative to understand their effects on a biological system. In this presentation, I will demonstrate to evaluate the toxicity of silver nanoparticles using S. cerevisiae yeast assays. Physiochemical properties of silver nanoparticles have shown a relatively large impact on the yeast cell growth. By leveraging the ability to make silver nanoparticles with a tight control in size and shape, we have identified that surface chemistry indeed plays a significant role in affecting the toxicity levels of silver nanoparticles. Specifically, we found that capping agents, surface facets and sample aging can affect the toxicity of nanoparticles. Previously the toxic responses of cells in relation to the surface chemistry of silver nanoparticles were not fully examined, and as a result, the correlation between nanotoxicity and other physicochemical properties established in literature may not reflect the nature of nanoparticles in causing toxicity. Here the findings in this work have attracted our attention to the matter that we have to carefully design experiments to eliminate possibilities that may arise from the environment surrounding nanoparticles and cells in toxicity assay. It also emphasizes the importance of surface modification to controlling the toxicity level of nanoparticles, in order to design safe nanomaterials for future commercialization and use.
11:45 AM - GG2.7
Characterization of Ion Releasing Kinetics of Ag Nanoparticles.
Hee Ok Park 1 , LianQing Li 1 , Sung Yang 1 Show Abstract
1 Applied Chemistry, Kyung Hee University, Yongin Korea (the Republic of)
Recently, there have been great interests in preparation and characterization of noble metal nanoparticles owing to their potential applications in nanoelectronics, nanophotonics, chemical sensing, and biological imaging. In particular, Ag nanoparticles have attracted much attention for their potential applications in electronics, antimicrobial agent, and sensor applications. It is well known that Ag nanoparticles could release toxic Ag ion and silver ion is 10, 000 times more toxic than silver nanoparticles, In this regard, the elucidation of the impact of Ag nanoparticles to the environment is complicated due to uncertainty in concentration of released Ag nanoparticles and Ag ions. So, the quantification of Ag ions released from Ag nanoparticles is essential to evaluate the possible health effects and environmental risks of Ag nanoparticles including the hazardous properties and the dose-response relationships. We have synthesized different sizes of Ag nanoparticles and modified surface property via ligand exchange reaction. We have determined the concentration of Ag ions using Ag ion sensitive fluorescent molecules. We have characterized the physico-chemical properties including size, surface chemistry, aggregation of Ag nanoparticles and their relationship with releasing kinetics of Ag ion and cytotoxicity.
12:00 PM - GG2.8
Natural Detoxification of Nanosilver through Environmental Oxysulfidation Reactions.
Jingyu Liu 1 , Kelly Pennell 2 , Robert Hurt 1 Show Abstract
1 Institute for Molecular and Nanoscale Innovation, Brown University, Providence, Rhode Island, United States, 2 , University of Massachusetts, Dartmouth, Massachusetts, United States
Among the many new engineered nanomaterials, nanosilver is one of the highest priority cases for environmental risk assessment. Recent analysis of field samples from water treatment facilities suggests that silver is converted to silver sulfide, whose very low solubility can limit the bioavailability and adverse impact of silver in the environment. Very little is known about the kinetics and mechanisms of this natural detoxification process. The present study demonstrates that silver nanoparticles react with dissolved sulfide species (HS-, S2-) under relevant but controlled laboratory conditions to produce silver sulfide nanostructures similar to those observed in the field. The reaction is continuously tracked by time-resolved sulfide depletion measurements to yield quantitative reaction rates and stoichiometries. The reaction is observed to require dissolved oxygen, and to be sensitive to pH and natural organic matter. The reaction is an oxysulfidation, and under laboratory conditions proceeds to complete conversion of AgNPs to Ag2S nanoparticles by a direct solid-fluid reaction. Focused-ion-beam analysis of surface films reveals an irregular coarse-grained sulfide phase that allows deep (> 1 µm) conversion of silver surfaces without passivation, explaining the ability of AgNPs to undergo complete internal conversion. At low sulfide concentration, quantitative kinetic analysis suggests a mechanistic switch to an indirect, oxidative dissolution/precipitation mechanism, in which the biologically active Ag+ ion is generated as an intermediate. The environmental transformation pathways for nanosilver will vary depending on the media-specific competing rates of oxidative dissolution and direct oxysulfidation, and this competition will determine whether the biologically active Ag+ species reaches sensitive environmental targets. The implications for nano-silver environmental risks will be discussed.
12:15 PM - GG2.9
Metal Electrode Dissolution during In Vitro Biphasic Current Stimulation.
Danielle Rand 1 , Josine Loo 1 , Jens Rip 1 , Wolfgang Eberle 1 Show Abstract
1 , imec, Leuven Belgium
Implantable electronic devices for central nervous system interfacing are currently being used for both clinical applications and fundamental research. These devices are being used as therapies for neurological disorders that cause impairment of sensory, motor, and cognitive systems, including Parkinson’s disease and obsessive compulsive disorder. Their primary functionality is to monitor electrical and neurochemical brain activity, as well as to stimulate neuronal populations at requisite spatial resolutions for a specific period of time. Thus, strict demands for safety and long-term reliability must be met.The most pressing technical challenge is the reliability of the electrodes. Because high spatial selectivity requires the use of small electrodes, appropriate electrode materials must be employed that can sustain the unavoidably high current densities that occur during stimulation. Due to the presence of various metals with different mobility and corrosion properties, it is important to decipher which metals are diffusing through the layers. Here, we assess the dissolution of Pt and W through varying thicknesses of TiN electrodes using a range of biphasic current stimulation pulses.A three-electrode configuration was used for the current stimulation. The TiN working electrodes had a diameter of 16 mm, with thicknesses of 10-100 nm. The metal layers underneath the TiN electrodes were Ti/Pt/Ti (20/200/20 nm), or W (350 nm), where the Ti served as an adhesion layer for the TiN. The TiN was exposed to phosphate buffered saline (PBS, 150 mM NaCl, pH 7.4), and biphasic current pulses were applied at various current densities. The PBS was then collected and analyzed for trace amounts of metal dissolution using total reflection X-ray fluorescence.The results show that more aggressive stimulation results in higher metal dissolution. As the stimulation current density increased from 0, 0.15, 0.25, and 0.35 A/cm2 there was an increase in Pt dissolution of 9.72, 348.03, 431.72, and 789.16 ppb, respectively. The rapid increase of Pt concentration with increasing current densities confirms that a significant amount of Pt can migrate through 100 nm TiN electrodes. A similar trend was also seen in the case of W. We also investigated the thickness of the TiN covering the W metal layer from 10-100 nm, and saw a marked decrease of W dissolution when using 100 nm TiN. In this case, the W dissolution concentration ranged from 13.78-30.98 ppb, which represented a 52.26-81.38% decrease in W dissolution as compared to the W dissolution measured with the thinner 10 nm TiN layer. Thus, the final TiN electrode thickness was determined to be a crucial dimension. Together, these results can lead to intelligent electrode material design as well as safer neuronal stimulation protocols.
GG3: Nanosafety III
Wednesday PM, November 30, 2011
Room 209 (Hynes)
2:30 PM - **GG3.1
Toxicity Issues in the Application of Carbon Nanotubes to Biological Systems.
Prabhakar Bandaru 1 , Constantine Firme 1 Show Abstract
1 , UC, San Diego, la Jolla, California, United States
Carbon nanotubes (CNTs) have recently emerged as a new option for possible use in methodologies of cancer treatment, bioengineering, and gene therapy. This talk analyzes the potential, through possible toxicological implications, of CNTs in nanomedicine. However, proven success in other fields may not translate to the use of CNTs in medicine for reasons including inconsistent data on cytotoxicity and limited control over functionalized-CNT behavior, both of which restrict predictability. Additionally, the lack of a centralized toxicity database limits comparison between research results. To better understand these problems, we seek insight from currently published toxicity studies, with data suggesting post exposure regeneration, resistance, and mechanisms of injury in cells.
3:00 PM - **GG3.2
Evaluating the Published Literature on the Safety of Oral Exposure to Nanomaterials.
Jeffrey Card 1 , Tomas Jonaitis 2 , Shahrzad Tafazoli 2 , Bernadene Magnuson 3 Show Abstract
1 Pharmaceutical and Healthcare Group, Cantox Health Sciences International, an Intertek Company, Mississauga, Ontario, Canada, 2 Food and Nutrition Group, Cantox Health Sciences International, an Intertek Company, Mississauga, Ontario, Canada, 3 Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
With increasing interest in the use of nanomaterials in a wide variety of industries, the number of published studies on the safety of nanomaterials continues to grow. As toxicological evaluations on a given nanomaterial may yield conflicting results, assessment of the reliability of each study is required to objectively interpret the overall safety of the nanomaterial. A two-step Nano Study Score method was developed to assess the overall quality of studies that examine the toxicity of nanomaterials. The first step utilizes a publicly available tool to rank the reliability of a given toxicological study based on the adequacy of its design and of its documentation of methods, materials, and results; this provides a “study score”. The second step involves determination of the completeness of physicochemical characterization of the nanomaterial(s) that is (are) being assessed within the study; this provides a “nanomaterial score”. The ‘‘study score’’ and the ‘‘nanomaterial score’’ are combined to derive a Nano Study Score, a two-part numerical value that provides an indication of the overall quality of the study. This approach is encouraged for studies conducted with nanomaterials to promote the notion that the combination of a reliable study and sufficient nanomaterial characterization within that study is of significantly greater value than either of these alone. The Nano Study Score method was applied in an evaluation of the published literature pertaining to the safety of oral exposure to food-related nanomaterials. A comprehensive literature search identified 30 publications in which a toxicological endpoint was assessed following in vivo (oral) or in vitro exposure to food-related nanomaterials. Of the 21 in vivo studies evaluated, 20 used mice or rats, 15 were lacking in some critical component of study design (e.g., oral gavage dose volume was not reported), none was longer than 90 days in duration, and only 7 reported more than 5 physicochemical parameters for the nanomaterial(s) being evaluated. Of the 9 in vitro studies evaluated, 7 focused on cytotoxicity, 2 evaluated genotoxicity, only 5 reported more than 5 physicochemical parameters for the nanomaterial(s) being evaluated, and none discussed the potential interference by the nanomaterial(s) of the experimental assays that were employed. The results of this evaluation indicate that there are currently insufficient reliable data to allow clear assessment of the safety of oral exposure to food-related nanomaterials. Significant investment must be made to generate studies of sufficient quality and duration, and that report comprehensive nanomaterial characterization such that results can be judged reliable and interpretable. Moreover, it is anticipated that the use and evolution of the Nano Study Score method will assist with the design, reporting, review, and interpretation of studies evaluating the potential toxicity of nanomaterials administered by various routes.
3:30 PM - GG3.3
The Structure, Composition, Dimension and Photochemical Behavior of Nanoscale TiO2 and ZnO Sunscreen Ingredients.
Zuzanna Lewicka 1 , Vicki Colvin 2 Show Abstract
1 Electrical and Computer Engineering, Rice University, Houston, Texas, United States, 2 Department of Chemistry, Rice University, Houston, Texas, United States
Nanosized titanium dioxide (TiO2) and zinc oxide (ZnO) are widely used inorganic sunscreen pigments. However, their dimensions and forms are rarely indicated on commercial product labels. Examination of nanoscale sunscreen components is essential for recognizing and managing possible effects of these engineered nanomaterials because TiO2 and ZnO are also well known photocatalysts that can generate DNA-damaging reactive oxygen species in aqueous media. We report the complete physicochemical characterization of these nanomaterials. Their dimension, shape, crystal phase, surface area, and elemental composition were examined using transmission and scanning electron microscopy, x-ray diffraction, BET surface area analysis, energy dispersive x-ray and inductively coupled plasma optical emission spectroscopy. We also tested the photochemical properties of the whole sunscreen emulsions that contained nanoscale components, the inorganic particles derived from these sunscreens, and several commercial TiO2 and ZnO nanopowders qualitatively by measuring the luminol chemiluminescence, dichlorofluorescein fluorescence and the decolorization of dyes (Congo Red and Rose Bengal). A more quantitative measurement of photo-efficiency was obtained with spin trap electron paramagnetic resonant spectroscopy. The major factors that determined the photocatalytic activity of sunscreen pigments were their elemental composition and surface modification. ZnO pigments acts more efficiently than TiO2. Future efforts are to better understand the role of sunscreen nanomaterial properties that contribute to photoactivity and to design photoinactive, safe and effective inorganic sunscreen components.
3:45 PM - GG3.4
Investigating the Safety of TiO2 Nanoparticles in Cosmetics.
Joo-kyung Lee 1 , Ah Young Kim 1 , Hyun Suk Jung 3 , Se-Hoon Han 3 , JiYeong Won 4 , JunHong Min 4 , EunGyu Lee 4 , BaeHo Park 1 , HeaYeon Lee 1 2 , Lim Seo Yul 1 , Kim Mi Ran 1 Show Abstract
1 Division of Quantum Phases and Devices, Konkuk University, Seoul Korea (the Republic of), 3 School of Advanced Materials Engineering, Kookmin University, Seoul Korea (the Republic of), 4 College of BioNano Technology, Kyungwon University, Seongnam Korea (the Republic of), 2 The Institute of Scientific and Industrial Research, Osaka University, Osaka Japan
Recently, much attention has been paid to nano-toxicology, which concerns the safety and hazardous nature of nanomaterials. Careful evaluations of nanoparticles (NPs)-associated toxicity are essential for future advances in nanobiotechnology. Note that nanomaterials, such as nano-sized vesicles or titanium dioxide (TiO2) or zinc oxide (ZnO) NPs, are currently used widely in the cosmetic field. Especially, TiO2 nanoparticles are used cosmetics of sun-cream to block UV radiation since it has physical properties diffusing and reflecting UV radiation. This research is to clarify the physical and chemical properties of the ingredients and to formulate solutions that evaluate and warrant safety to human health. In this research, I will present a novel scheme to evaluate the toxic properties of TiO2 nanoparticles in cosmetics by using an electrochemical assay, a conventional biochemical assay, TEM, ROS(reactive oxygen species) measurement. AC impedance measurements can be used to evaluate rapidly nano-safety relations between a cell and surface-modified NPs.
4:30 PM - GG3.5
Effect of TiO2 Particles on Human Skin Cells.
Chienhsiu Lin 1 , Alexander Lee 3 , Marcia Simon 2 , Kayla Applebaum 4 , Miriam Rafailovich 1 Show Abstract
1 Material Science & Engineering, SUNY at Stony Brook, Stony Brook, New York, United States, 3 , Hauppauge high school, Hauppauge, New York, United States, 2 Oral Biology and Pathology, SUNY at Stony Brook, Stony Brook, New York, United States, 4 , Ma'ayanot Yeshiva High School for Girls, Teaneck, New Jersey, United States
Titanium dioxide (TiO2) particles are widely used in all types of personal care products. However, the effect of these particles on human skin is still under question. In order to understand the effects of these particles on human skin tissue, we have undertaken a comprehensive study where we compare the effects for a given concentration on different types of cells composing the skin tissue. We have found that keratinocytes are the least susceptible to damage and have the capacity to sequester the particles within the intercellular spaces. Exposure to the particles causes cell death at doses in excess of 0.5 mg/ml and for lower doses (less than 0.1mg/ml) adipogenic differentiation and lipid formation is suppressed. Furthermore, even when lipids have formed, breakage of membranes is observed. Coated TiO2 particles, on the other hand, had only minimal effects on all cell types. The effects of low dose radiation on the damage were also explored, and we found no significant difference in additional damage relative to the controls. These results indicated that the predominant mechanism of damage by these particles was not due to photoactivation by either UVB or UVA, rather most of the damage occurred simply by the presence of the particles, even in the absence of UV exposure.
4:45 PM - **GG3.6
Hydrogenation of Chlorobenzene to Cyclohexane over Pt Nanocatalysts under Ambient Conditions.
Manhong Liu 1 , Xinxin Mo 1 , Yanyan Liu 1 , William Yu 1 2 Show Abstract
1 College of Material Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, China, 2 College of Electronic Science and Engineering, Jilin University, Changchun, JIlin, China
A series of finely dispersed poly(vinyl-2-pyrrolidone)-stabilized platinum colloidal nanocatalysts (PVP-Pt) were prepared and characterized by TEM. Hydrogenation of monochlorobenzene (MCB) was carried out in a batch mode over PVP-Pt at 25°C and 1 atm, nearly 100 % selectivity to cyclohexane could be obtained at 100 % conversion of MCB. The catalytic performance of the PVP-Pt colloids was dependent on the preparation conditions. The reaction was verified to be the first order to the concentration of MCB. We further investigated the immobilized Pt nanoparticles for MCB hydrogenation. Polymer-stabilized noble metal nanoparticles have exhibited excellent performance in the remediation of chloroaromatic compounds in the environment. However, their separation and recovery from the reaction system is challenging. One method to recover them is to immobilize them on supports, such as Al2O3. Hydrogenation of MCB was carried out using hydrogen at 25°C and 1 atm over Al2O3 supported uniform Pt nanoparticles (Pt/Al2O3). The reactions were accomplished in 10 h with satisfactory results in activity and selectivity. The as-prepared Pt/Al2O3 could be good recoverable nanocatalysts for hydrodehalogenation and reduction of various chloroaromatic compounds in the environment.
5:15 PM - GG3.7
Recycling and Reuse of Single-Wall Carbon Nanotubes from Portable Energy Storage Systems.
Christopher Schauerman 1 2 , Matthew Ganter 1 2 , Gabrielle Gaustad 2 , Callie Babbitt 2 , Ryne Raffaelle 1 , Brian Landi 1 Show Abstract
1 NanoPower Research Laboratories, Rochester Institute Of Technology, Rochester, New York, United States, 2 Golisano Institute of Sustainability, Rochester Institute of Technology, Rochester, New York, United States
Large scale incorporation of engineered nanomaterials into industrial systems and commercial products is relatively new, and therefore little attention has been given for life-cycle options when these products reach their end-of-life (EOL). Often, nanomaterials are engineered within narrow property tolerances (diameter, crystal structure, density, surface area, etc) to achieve specific device performance. The ability to recycle them without altering their properties outside of acceptable ranges will depend on processing costs, environmental impact, and nanomaterial/application specific factors. Of particular interest, is the use of single-wall carbon nanotubes (SWCNTs) in sustainable energy devices like batteries in portable power systems. EOL strategies will become an increasing concern for waste streams as the synthesis and utilization of SWCNTs begins its scale-up. Recycling and remanufacturing of SWCNTs into like-virgin materials represents a significant step forward in the life cycle of these materials and could make it possible to reduce costs by distributing the high embodied energy of synthesis over multiple use phases. During the course of this study, SWCNTs were synthesized via laser vaporization, purified through a combination of acid reflux and thermal oxidation steps, fabricated into SWCNT free standing papers, and used as electrodes in Li+ battery coin cells. The SWCNT-Li+ coin cells were forced to their EOL though extended cycling at high C-rates, and disassembled in an inert glove box where the material was recovered. The recyclability of the recovered EOL-SWCNTs was investigated. Specifically, a series of acid and thermal oxidation treatments, originally developed for the purification of as-produced SWCNT material were successful in removing the solid electrolyte interface, one failure mechanism of the Li+ coin cells. The recycled-SWCNT material was successfully incorporated into new Li+ battery electrodes with comparable insertion and extraction capacities to the virgin pure-SWCNT electrodes (i.e. 650 mAh/g which represents a 2x improvement over state of the art graphite materials). The recycled SWCNT material was characterized at each step in the recycling process through a combination of scanning electron microscopy, thermal gravimetric analysis, Raman spectroscopy, and optical absorption spectroscopy. The life cycle energy required for recycling procedures was measured and compared to the published values of SWCNT synthesis. The ability to recover EOL SWCNTs and recycle them to their initial functionality has been demonstrated for the first time, and the energy required to recycle the nanomaterials was measured during the process and is less than the energy required to synthesize new material.
5:30 PM - GG3.8
Synthesis of 14C-Labelled Carbon Nanotubes for In Vivo Biodistribution Studies.
Mathieu Pinault 1 , Sami Habib 1 , Gaelle Kerric 2 1 , Dominique Georgin 2 , Frédéric Taran 2 , Bertrand Czarny 3 , Vincent Dive 3 , Martine Mayne-L'Hermite 1 Show Abstract
1 DSM/IRAMIS/SPAM, CEA Saclay-Laboratoire Francis Perrin, Gif sur Yvette Cedex France, 2 , CEA, IBITECS, Service de Chimie Bioorganique et de Marquage, Gif sur Yvette Cedex France, 3 , CEA, IBITECS, Service d'Ingénieurie Moléculaire des Protéines, Gif sur Yvette Cedex France
Carbon nanotubes (CNT) are currently developed for multiple future commercial applications. It is therefore more than ever necessary to address their health safety implications and in particular explore their in vivo biodistribution and pharmacokinetics. One critical point for such investigation is the labelling strategy of CNT in order to track their behavior and fate in the body that could lead to some surface modifications influencing interactions of CNT with biological materials.In a first step we developed a post treatment method that allows the uniform 14C-labeling of purified MWCNT without modifying their structure. Their subsequent use in pilot in vivo biodistribution investigations will be described. In order to increase the specific activity of the 14C-labelled MWCNT (more than 100 µCi/mg) we modified the aerosol-assisted CCVD process. For the first time, long and aligned MWCNT were synthesized by the direct use of 14C-labelled benzene as the carbon source and were fully characterized before using this new material for biodistribution studies. References D. Georgin, B. Czarny, M. Botquin, M. Mayne-L’Hermite, M. Pinault, B. Bouchet-Fabre, M. Carriere, J-L. Poncy, Q. Chau, R. Maximilien, V. Dive and F. Taran. J. Am. Chem. Soc. 2009, 131, 14658-14659.  Pinault, M.; Pichot, V.; Khodja, H.; Launois, P.; Reynaud, C.; Mayne-L’Hermite, M. Nano Lett. 2005, 5, 2394-2398
5:45 PM - GG3.9
Carbon Nanotube Filtration Products: Determination of Potential Release.
Michelle Cavaliere 1 , Whitney Hill 1 , Steven Compton 1 Show Abstract
1 , MVA Scientific Consultants, Duluth, Georgia, United States
An increasing number of consumer products contain nanomaterials with estimates predicting that by 2014, $2.6 trillion in manufactured goods or approximately 15% of total global output will incorporate nanotechnology . In particular, carbon nanotubes (CNTs) have been incorporated into a variety of commercially available materials due to their unique properties. This surge in nanomaterial production and assimilation into commercially available products has manufacturers, consumers, and regulatory agencies concerned with the issue of potential nanoparticle exposure and the possible health risks associated with exposure . We are currently developing complementary microscopical methods that can be employed to test consumer products for exposure risks. This study focuses on exposure from air and water filtration products, which have the potential to release CNTs during normal operation.In the first investigation a water filtration unit, containing both CNTs and activated carbon, was tested for release of nanotubes during normal operation. Several product units were received and parallel product operation lines were constructed from which a known volume of liquid could be collected at specific flow intervals. The collected liquid samples were filtered through membrane filters and the filters were prepared and analyzed for carbon nanotubes following analytical procedures modified from those commonly used for asbestos fiber analysis. Transmission electron microscopy (TEM) was utilized to differentiate CNTs and activated carbon based on particle morphology with comparison to reference samples.The second investigation involved examination and testing of a CNT-containing air filtration device. Of particular interest in the characterization of the product were the materials comprising the filter, their spatial relationship to each other, and the distribution of the CNTs within the filter material. The complementary techniques of scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and confocal Raman microscopy (CRM) were employed to examine the filter. In order to assess the potential for CNT release, the product was utilized in a controlled chamber with measurable airflow through the filter and into a sampling channel containing filter cassettes to collect CNTs. Transmission electron microscopy (TEM) was used to identify particles as nanotubes based on their morphology and elemental composition, as well as a comparison with known nanotube reference samples from the test material. ReferencesLux Research, The Nanotech Report, 5th Ed., Lux Research, New York, 2007.Department of Health and Human Services/Centers for Disease Control and Prevention/ National Institute for Occupational Safety and Health, Approaches to Safe Nanotechnology: Managing the Health and Safety Concerns Associated with Engineered Nanomaterials, DHHS/NIOSH, Feb. 2009.
GG4: Poster Session
Wednesday PM, November 30, 2011
Exhibition Hall C (Hynes)
9:00 PM - GG4.1
Workplace Safety in Polymer Nanocomposite Research.
Cyrill Cattin 1 , Maximilien Debia 2 , André Dufresne 2 , Pascal Hubert 1 Show Abstract
1 Department of Mechanical Engineering, McGill University, Montreal, Quebec, Canada, 2 Département de santé environnementale et santé au travail, Université de Montréal, Montréal, Quebec, Canada
In recent years, research efforts to develop and advance nanoparticles (NPs) and NP based composite materials have been increasing rapidly. Well-known examples of such materials are carbon nanotubes (CNTs) and CNT modified polymers. Typically, research on CNT/polymer nanocomposites involves handling of dry CNTs. Although occupational and environmental health and safety practices are in place for the handling of most polymers and chemicals involved in such research, for the handling of dry CNTs this is not the case. For a long time it was assumed that CNTs are not particularly hazardous and little effort was devoted to evaluating the toxicity of these NPs. A recent study, however, demonstrates that CNTs introduced into the abdominal cavity of mice show asbestos-like pathogenicity, and, hence, may pose a carcinogenic risk . Overall, conclusions from studies exploring the possible adverse effects of CNTs, and NPs in general, vary considerably. Adequate knowledge of toxicity does often not exist, but it has been shown that NTs, and CNTs in particular, can be highly toxic. The presented work addresses this problem and proposes a working practice to minimize/eliminate potential health, safety, and environmental risks associated with the handling of dry NPs in laboratory research. The aim of the proposed practices is to minimize/eliminate exposure to NPs, i.e. adequate laboratory equipment and personal protective equipment should prevent from inhalation, dermal uptake, ingestion and injection of NPs. It has been shown that local exhaust ventilation is key in minimizing/eliminating exposure to NPs, but is also strongly dependant on the laboratory equipment (e.g. fume hood or biosafety cabinet) . The proposed practice uses a glove box with attached vacuum chamber for material transport and air cleaning. The practice is explained in detail, and an analysis of the used laboratory equipment in terms of workplace safety is presented. References:  C. A. Poland, R. Duffin, I. Kinloch, A. Maynard, W. A. H. Wallace, A. Seaton, V. Stone, S. Brown, W. MacNee and K. Donaldson, Nat Nanotechnol 3 (2008), p. 423.  L. G. Cena and T. M. Peters, Journal of Occupational and Environmental Hygiene 8 (2011), p. 86.
9:00 PM - GG4.10
In Vitro Toxicity Evaluation of Nanodiamond-Polyaniline Composite in Mammalian Cells.
Pedro Villalba 1 4 , Manoj Ram 2 , Humberto Gomez 3 4 , Amrita Kumar 5 , Ashok Kumar 2 3 Show Abstract
1 Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, Florida, United States, 4 College of Medicine, Universidad del Norte, Barranquilla Colombia, 2 Nanotechnology Research & Education Center, University of South Florida, Tampa, Florida, United States, 3 Department of Mechanical Engineering, University of South Florida, Tampa, Florida, United States, 5 Department of Physiology, Emory University , Atlanta, Georgia, United States
Exploitation of nanomaterials for bio-applications has been an active research area in recent years as a consequence of their unique structures, surface chemistry and physical properties. The nanomaterials are highly desirable for their interaction with biological tissues. The functionalized nanodiamonds (ND) and it’s composite are rapidly emerging as promising materials for the next generation of drug delivery agents, biosensors, or imaging contrast applications due to mechanical and chemical properties. Besides, conducting polymer such as polyaniline (Pani) is widely studied biomedical material, with application in biosensor and tissue engineering, because of its unique electrochemical, physical, and high conductivity properties. Combining the mechanical and chemical stability of ND with the notorious conductivity of PANI allows us to overcome the limitations of the use of only a single component. Potentially, ND-Pani nanocomposites may have several biological applications, thus, it is important to test the health risks that might be associated with exposure of nanoparticles. For instance, toxicity is a critical factor to consider when evaluating the potential use of nanocomposite materials. It is important to ensure that ND-Pani material do not cause adverse effects once converged to biomaterials. In order to understand whether pristine or conjugated ND-Pani composite is toxic to cells, we have performed a vitro toxicity studies using ND-Pani in different concentration with varied incubation times.The objective of this work is to study the cytotoxic effects of the ND/PANI composite in human epithelial kidney cell (HEK) line under in-vitro conditions. Toxic effects of ND and ND/Pani nanocomposite as powder on HEK cells were tested using MTT assay. Results indicated that there was no statistical difference for ND/Pani, PEG (positive control) and control sample at low concentration (0.1 µg/ml and 1µg/ml) (p<0.05). Morphology of the cells was not significantly affected due to the inclusion of nanocomposites during the incubation phase. The stability of the film was improved due to the inclusion of the nanodiamond particles into the polymeric matrix. Experimental results showed that ND-Pani composite is not completely harmless to the cell line used; but at lower concentration the effect is negligible, thus indicating that there is a safe range where this material can be used without secondary effects due to its toxicity and making it suitable for electrochemical sensing application.
9:00 PM - GG4.11
Synthesis and Characterization of Functionalized Fe3O4 Nanoparticles in Organic Phase.
Jing Li 1 2 3 , Jieying Jing 1 2 3 , Qingbo Zhang 3 , Vicki Colvin 3 , Wenying Li 1 , William Yu 1 3 Show Abstract
1 Key laboratory of coal science and technology, Taiyuan university of technology, Taiyuan, Shanxi, China, 2 College of Chemistry and Chemical Engineering, Taiyuan university of technology, Taiyuan, Shanxi, China, 3 Department of Chemistry, Rice university, Houston, Texas, United States
Iron oxide nanoparticles (Fe3O4, magnetite) have been a research topic of great interest over the past decades due to their magnetic properties. Functionalized Fe3O4 nanoparticles dispersed in the water have been extensively studied. However, these particles are not suitable for organic reaction systems. In this work, we report a simple strategy to synthesize of magnetic Fe3O4 nanoparticles with free functional group in organic phase. Oleic acid stabilized Fe3O4 nanocrystals were prepared by thermal decomposition. The oleic groups were then replaced by substituted reactions with a dimer acid bearing carboxyl groups. The structure changes of the capping molecules on the nanoparticle surface was investigated with Fourier transform infrared (FTIR) spectroscopy and Thermogravimetric analysis(TGA), the free carboxyl groups on the particle surface were confirmed. The shape and the magnetic properties of the nanoparticles were maintained after the substituted reaction. The as-prepared organic solvent dispersed iron oxide nanocrystals were extremely stable and coated free functionalized group for further application.
9:00 PM - GG4.12
Characterizations of B2O3-P2O5-ZnO-Cu2O Lead Free Filling Glass for Rubies.
Minkyung Kang 1 , Hunhyeong Lee 1 , Dongwook Shin 1 Show Abstract
1 Division of Materials Science and Engineering, Hanyang university, Seoul Korea (the Republic of)
Ruby is a variety of Corundum which has pink to dark red color, and the other colors are called Sapphire. Due to exceptional hardness and intensity, it's also popular for industrial use as well as jewelry. However, it is getting difficult to get fine quality rubies and the volume of ruby supply to the market getting less due to limited reserves and complicated mining process. The studies about variety treatments to enhance the appearance of low quality rubies which are not suitable for jewelry are having done since long time ago. The most common treatment is the application of heat. Most, if not all, rubies at the lower end of the market are heat treated on the rough stones to improve color, remove purple tinge, blue patches and silk. Another treatment, which has become more frequent in recent years, is lead glass filling. Filling glass is a material which heals the fractures, fissures, cracks and voids inside the gemstones to improve visual appearance and mechanical strength. Since Pb is harmful for environment and human, the demand for lead free filling materials is increasing same as other industrial material markets. In this study, B2O3-P2O5-ZnO system was selected as a host for lead free filling glass and the Cu2O were added as dopant for rubies. B2O3-P2O5-ZnO glasses of various compositions doped Cu2O of 0.1 mol% was melted in the reduction atmosphere for objective color with natural rubies. Infrared(IR) and Raman spectra were observed for confirmation these structures of glasses. The proportion of ZnO (50, 55 and 60 mol%) was adjusted to fit the refractive index of natural rubies (1.76-1.77). The coefficient of thermal expansion (C.T.E.) was measured by Thermo-mechanical analysis (TMA) to compare with the value of natural rubies. Also, transitional temperature (Tg) and crystallization temperature (Tc) are determined by means of differential thermal analysis (DTA). The color property and transmittance was confirmed by UV visible spectroscopy. The wetting angle was measured for the determination of work of adhesion of glass and natural ruby and chemical durability of B2O3-P2O5-ZnO glass was evaluated by weight loss of glass samples after immersion in water and acetone solutions.
9:00 PM - GG4.13
The Effect of Mn on the Abrasive Wear Resistances of Cr-Free Fe-Mn-C-Si-B Hardfacing Alloys.
Kinam Kim 1 , Hyewon Kim 1 , Taeho Kim 1 , Jaeyong Yun 1 , Seonjin Kim 1 Show Abstract
1 Materials Science & Engineering, Hanyang University, Seoul Korea (the Republic of)
The effect of Mn on the abrasive wear behaviors of Cr-free Fe-xMn-3C-1Si-0.5B (x = 1-5 wt.%) hardfacing alloys was investigated. Among these, the 3Mn alloy exhibited the least amount of weight loss after 2000 cycles of the abrasive wear test. This result is most likely due to the morphology and the increasing volume fraction of block-type Fe boro-carbide at an Mn concentration of 3 wt.%. The carbide blocks of 3Mn alloy appear to prevent damage by abrasive particles due to its shape and narrow inter-carbide spacing. The 3Mn alloy also had a lower volume fraction of eutectic phases that are vulnerable to abrasion.
9:00 PM - GG4.14
Safety Evaluation of Titanium Dioxide Nanoparticles on Human Skin-Tissues.
Ah Young Kim 1 , Joo-Kyung Lee 1 , Hyun Suk Jung 3 , Se-Hoon Han 3 , BaeHo Park 1 , HeaYeon Lee 2 1 Show Abstract
1 Division of Quantum Phases and Devices, Konkuk Univ., Seoul Korea (the Republic of), 3 School of Advanced Materials Engineering, Kookmin University, Seoul Korea (the Republic of), 2 The Institute of Scientific and Industrial Research, Osaka University, Osaka Japan
Biological effects of nanomaterials with a focus on toxicity should receive great attention since commercial products as well as medical tools increasingly utilize them. Especially, a fundamental understanding of nanotoxicology is highly desirable both from the material’s stand point as well as from the biological system’s point of view. Titanium dioxide (TiO2) is a widely used material in materials sciences and engineering due to its optoelectronic properties. For example, TiO2 has been utilized as photocatalysts for photochemical hydrogen production and for self-cleaning windows. In the cosmetic industry, titanium dioxide is the main ingredient in many commercial sunscreens along ZnO due to its property of UV absorption. However, despite its wide array of common applications, TiO2 nanotoxicology has focused on cellular level toxicity studies. In this work, the toxicity of TiO2 nanoparticles on human skin-cell and tissue in cosmetics were investigated using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay- and confocal microscopy for live & dead of cells. The human skin-cell and tissues were purchase from Korean Cell Line Bank. We observed that TiO2 nanoparticles impedes the cell growth using MTS, and dead cells were increased depending on the concentration of TiO2 nanoparticles using confocal microscopy, electrochemical analysis, TEM, ROS(reactive oxygen species). Based on the results mentioned above, we discuss the toxicity and the safety of TiO2 nanoparicles in cosmetics for the human cells and tissues.
9:00 PM - GG4.15
Understanding the Interactions between Metallic Nanoparticles and Cell Membrane Models.
Thiers Uehara 1 , Paulo Miranda 1 , Valtencir Zucolotto 1 Show Abstract
1 , Universidade de São Paulo-USP, São Carlos Brazil
Nanoparticles and nanotubes have been widely explored in biomedical applications as active engineered materials for diagnosis and therapy. With the great potential of using these nanocomposites in biological systems, such as in the manufacture of small materials for biotechnological application, it is very interesting to understand how these materials interact at the molecular level with cell membranes in living systems. In this study we investigated the interactions between superparamagnetic nanoparticles and cell membrane models using the technique of vibrational sum frequency generation-SFG spectroscopy, specific for interfaces. The membrane models comprised Langmuir phospholipid monolayers composed by DPPC (dipalmitoylphosphatidylcholine) and DPPG (dipalmitoylphosphatidylglycerol). The interaction between the nanoparticles and the membrane models was revealed via SFG as the decrease in the CH3 band at 2880 cm-1 in comparison to the band at 2942 cm-1. The investigation of the interactions between nanomaterials and membranes using SFG may be relevant for nanotoxicological studies.
9:00 PM - GG4.16
Efficacy of Silver Nanoparticles against Microbial Pathogens.
Almaz Gebregeorgis 1 , Kouassi Ayikoe 1 , John Stubbs III 2 , Dharmaraj Raghavan 1 Show Abstract
1 Chemistry, Howard University, Washington, DC, District of Columbia, United States, 2 Microbiology, Howard University, Washington DC, District of Columbia, United States
Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa are the etiological agents of several infectious diseases. Antibiotic resistance among these three microbes has emerged as a prevalent problem due in part to the misuse of existing antibiotics and the lack of novel antibiotics. Here we describe the method for synthesis of silver nanoparticles which has been evaluated for their efficacy against three etiological agents. Protein conjugated silver nanoparticles were prepared by chemical reduction and capping of silver nanoparticles with Bovine Serum Albumin (BSA). We utilized a disc diffusion assay to assess the antibacterial properties of silver nanoparticles. Zones of inhibition were compared as a function of silver nanoparticle concentration. Preliminary results suggest that silver nanoparticles are most efficient against S. aureus when compared to other test bacteria. Studies are underway to verify the antimicrobial characteristics of silver nanoparticles with other bacterial strains.Acknowledgment : NSF-DMR, NIH S06 GM 08016 -32
9:00 PM - GG4.18
Skin Cells Damage by the Exposure to Energy Saving Compact Fluorescent Light Bulbs and Titanium Dioxide.
Tatsiana Mironava 1 , Michael Hadjiargyrou 2 , Marcia Simon 3 , Miriam Rafailovich 1 Show Abstract
1 Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, New York, United States, 2 Department of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, New York, United States, 3 Department of Oral Biology and Pathology, School of Dental Medicine, State University of New York at Stony Brook, Stony Brook, New York, United States
Compact fluorescent light (CFL) bulbs are popular due to the fact that they can provide the same amount of lumens as incandescent light bulbs, using one quarter of the energy. However, CFL exposure was found to promote adverse skin conditions. The question of CFL effects on healthy tissues still has not been investigated. The effect of CFL bulb exposure and combination of CFL irradiation with TiO2 nanoparticles, common ingredient for the sunscreens and skin care products, has been investigated. Cells exposed to the CFL exhibited a decrease in the proliferation rate, a significant increase in the production of ROS, and a decrease in their ability to contract collagen, all common effects that have been previously reported after exposure to UVA and UVC radiation. The selected nanoparticle dosage (0.2 ug/ml) had no effect on cell function in the absence of CFL exposure or exposure to incandescent lighting, whereas cells containing anatase died after just a single CFL dose. Cells containing rutile sustained slightly more damage than the cells without particles after one radiation dose, but were completely destroyed following a second dose. In contrast, the cells without nanoparticles sustained less damage after the second irradiation. Eventhough both keraticnocytes and dermal fibroblasts sustained damage after exposure to the CFL, the extent was larger for the fibroblasts. That indicates that TiO2 nanoparticles can sensitize both types of cells to UV light, with the degree of sensitivity increasing with exposure time. Our results indicate that potential damage can result to skin tissue upon exposure to CFL lighting, and the presence of TiO2 nanoparticles may exacerbate the damage.
9:00 PM - GG4.19
Cytotoxicity of Silver Nanoparticles.
Georgios Sotiriou 1 , Anna Pratsinis 1 , Sotiris Pratsinis 1 Show Abstract
1 Particle Technology Laboratory, ETH Zurich, Zurich Switzerland
Silver nanoparticles are receiving more and more attention for their plasmonic colors and their antibacterial effects . The addition of a nanothin SiO2 shell minimizes the release of toxic Ag ions and the contact of cell or bacteria with the Ag particle surface.  Here the development and validation of a cellular test, such as the MTS, to quantitatively estimate/assess the cytotoxicity of various Ag nanoparticles is presented. The primary objective was to find optimal conditions for both Ag nanoparticles and cells, such that the nanoparticles do not sediment and the cells still survive. This method has the potential to be expanded to other cytotoxic tests, to get a broader understanding of the toxicity of such particles. References Sotiriou, G.A, Pratsinis, S.E. Antibacterial Activity of Nanosilver Ions and Particles. Environ. Sci. Technol. 44, 5649-5654 (2010).Sotiriou, G.A, Hirt, A.M., Lozach P.Y., Teleki A, Krumeich F., Pratsinis, S.E. Hybrid, Silica-Coated, Janus-Like Plasmonic-Magnetic Nanoparticles. Chem. Mater. 23, 1985-1992 (2011).
9:00 PM - GG4.2
Capturing Oxide Nanoscale Particles Using Electrostatic Deposition Method.
Andrey Stepashkin 1 , Margarita Churyukanova 1 , Sergey Kaloshkin 1 , Sergey Krivov 2 Show Abstract
1 CAMN, NUST "MISIS", Moscow Russian Federation, 2 , Moscow Power Engineering Institute, Moscow Russian Federation
The influence of nanoscale particles on human body has not been studied well. Preliminary studies have shown that nanoparticles can penetrate through epithelium sells, travel in nerve cells, blood and lymphatic vessels. High penetration ability, chemical and biological activity increase their threat for human health. It has been established that toxicity increases with the decrease of particle size. The use of standard ventilation systems leads to spreading of the nanoparticles over large distances.This work aims at studying the ability of electrostatic filters to capture nanoscale particles in the environment of scientific laboratories and production plants as well as at revealing the peculiarities of deposition of nanoparticles with different sizes and types.The surface of arrester plates in the filter used in the study was 7 m2. The speed of air flow varied from 3 to 12 m/sec. Compressed air was used to disperse powders of Al2O3 (particle size 10-50 nm), ZnO (particle size 30-80 nm), TiO2 (particle size 20-60 nm). The resulting aerosol was fed into the filter.The resulting sediment was studied on laser diffraction analyzer of particle size spread Fritsch Analysette-22 Nanotech, scanning electron microscope Hitachi TM-1000 and electron microscope JEOL JSM-6710.The analysis showed that up to 30% of the total number of particles captured by the filter were 10-50 nm in size, 50% represented aggregated nanoparticles and were 100-3000 nm in size, remaining 20% were relatively large dust particles (5-20 mkm) that were present in the air.The effectiveness of nanoparticles capturing was estimated to be 90%. The distribution of deposited particles on the arrester plates depending on size of the particles and inductive capacity of the material was analyzed. Understanding this distribution may allow to separate particles of different sizes and compositions.
9:00 PM - GG4.20
Design and Synthesis of Functional Silver Nanoparticles for Bacterial Inactivation.
Jin Luo 1 , Lingyan Wang 1 , Shiyao Shan 1 , Elizabeth Crew 1 , Jun Yin 1 , Bridgid N. Wanjala 1 , Chuan-Jian Zhong 1 Show Abstract
1 Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, United States
There is a growing interest in designing advanced metal particles in antimicrobial applications. While metals such as silver, gold, and zinc have been used for centuries as bactericidal and bacteriostatic agents, the engineering of the metals at the nanoscale enables a drastic increase of the surface area and other changes in surface physical and chemical properties. The formation of silver shells on magnetic nanoparticles could allow effective inactivation of bacteria in platelets while the particles can be removed from the platelet medium prior to transfusion, eliminating the possibility of side-effectives from residual materials. This report describes the synthesis silver-coated magnetic nanoparticles as a functional antimicrobial agent. The introduction of magnetic cores in the metal nanoparticles enables the capability of effective separation, delivery and targeting of the antibacterial agents. Magnetic MnZn Ferrite (MZF) nanoparticles and silver-coated magnetic nanoparticles (MZF@Ag) were synthesized by wet chemical methods, and were evaluated for bacterial inactivation of several types of bacteria, including gram positive and gram negative bacteria. The results have demonstrated the viability of the MZF@Ag for achieving effective bacterial inactivation efficiency comparable to or better than silver nanoparticles conventionally used. Implications of the findings to developing functional nanomaterials for effective removal of antibacterial agents after bacterial inactivation in platelet prior to transfusions are also discussed.
9:00 PM - GG4.21
Mechanical Study of Flame Retardant Bio-Degradable PLA/Ecoflex Nanocomposites.
Kai Yang 1 , Shan He 1 , Takashi Kashiwagi 2 , Miriam Rafailovich 1 Show Abstract
1 Materials Science and Engineering, SUNY-stony brook, stony brook, New York, United States, 2 Fire Research Division, NIST, Gaithersburg, Maryland, United States
In the pursuit of controlling flame retardant polymer, a wide variety of concerns will be considered in addition to flammability properties. Not only is this a very efficient FR combination, but it also have a widely usage as environmental friendly bio-degradable functional polymer. Nanocomposites of PLA/Ecoflex with organically modified clays and starch have been prepared. The effects of clay and starch loading on the morphology and combustion behavior have been evaluated using tensile testing, cone calorimetry and thermal gravimetric analysis. Synergy is observed between the polymer and additives, on the surface of burning polymer, clay and starch forms a hard cover surface protecting the polymer from heat and oxidation. This layer may act as an insulator slowing the escape of the volatile products ejecting when the polymer combination decomposed.
9:00 PM - GG4.22
Risk Governance of Environment, Safety and Human Health in Nanotechnology in Korea.
Jeong-Suk Moon 1 Show Abstract
1 Green Technology Development Office , Korea Environmental Industry & Technology Institute, Seoul Korea (the Republic of)
Currently, nanotechnologies have been received intense interests due to their significant implications including order-of-magnitude increases in computer efficiency, catalysts, sensors and a wide range of environmental remediations. Despite Nanotechnology is an important and rapidly growing field of scientific and practical innovations, little is known about the potential risks of nanomaterials and nanotechnology to human health and environment. Risk governance in nanotechnolgy is essential for assessing and managing the implications of nanotechnology since there exist debates about the relationship between nanotechnolgy, potential risk, and sustainable environment. I will deal with current status of potential risks associated with nanomaterials and nanotechnology and regional on-going research projects in Korea.
9:00 PM - GG4.23
Toxicity Effects of Unfunctionalized Mesoporous Silica on Alveolar Macrophages Studied In Vitro.
Kennedy Nguyen 1 , Gayatri Premasekharan 1 , Henry Forman 2 3 , Valerie Leppert 1 Show Abstract
1 School of Engineering, University of California, Merced, Merced, California, United States, 2 School of Natural Sciences, University of California, Merced, Merced, California, United States, 3 Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
Mesoporous silica nanoparticles have several potential applications, such as drug delivery via inhalation. They are of interest due to their tunable particle size and pore diameter, effectively allowing their transport from the lungs via the lymphatic system to target organs and the inclusion of different drug molecules within their pores. However, while the toxicity literature is extensive for micron-sized crystalline silica due to occupational health concerns, there is relatively little information available for mesoporous silica. Our recent studies of extensively characterized mesoporous nanoparticles indicate that at a dose of 100 μg/ml, alveolar macrophage cell viability as measured by MTT assay is decreased from 82 ± 8% to 73 ± 16% compared to solid silica. Further, DPPP assay results indicate that lipid peroxidation increases for mesoporous silica compared to solid silica particles. Here, we extend our studies to low, non-cytotoxic doses that approximate a more realistic exposure scenario in order to determine if lipid peroxidation is still present and if sub-lethal effects, such as the production of inflammatory mediators, occur. The effect of important particle parameters (particle and pore size, surface chemistry) is also investigated.
9:00 PM - GG4.24
Luminescent Gold Nanoparticles with Efficient Renal Clearance.
Chen Zhou 1 , Michael Long 2 , Yanping Qin 1 , Xiankai Sun 2 , Jie Zheng 1 Show Abstract
1 Chemistry, University of Texas at Dallas, Richardson, Texas, United States, 2 Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
To minimize nanotoxicity, ideal nanomaterial-based contrast agents should be effectively cleared out of the body and have little accumulation in organs. While significant progress has been made toward the creation of fluorescent quantum dots with efficient renal clearance, gold nanoparticles (AuNPs), another highly promising nanomedicine for in vivo applications of biomedical imaging, drug delivery and photothermal therapy, still severely hampered by their intensive nonspecific accumulation in the organs of the reticuloendothelial system (RES) after systemic administration and the consequenced long-term nanotoxicity. In this meeting, we will present a class of luminescent glutathione coated AuNPs, which exhibited 10 to 100 times better renal clearance efficiency than those of the similar-sized AuNPs coated with other ligands. Quantified by ICP-MS, only 3.7±1.9% of the particles were accumulated in the liver and more than 50% of the particles were found in urine within 24 h and up to 65% within 72 h after IV injection. The renal clearance was also imaged in real time with X-ray computed tomography (CT) imaging. A fundamental and quantitative understanding of how the particle size and surface ligands influence the renal clearance of AuNPs we gained from these studies will provide a new strategy for minimizing toxicity of nanostructures.
9:00 PM - GG4.3
Significance of Physicochemical Characterizations for Nanotoxicological Studies of AgNPs.
Jinkyu Roh 1 , Sumin Park 2 , Jongheop Yi 2 , Younghun Kim 1 Show Abstract
1 Chemical Engineering, Kwangwoon University, Seoul Korea (the Republic of), 2 Chemical and Biological Engineering, Seoul National University, Seoul Korea (the Republic of)
Recent advances and progress in nanotechnology have demonstrated many nanoparticles (NPs) as drug delivery vehicles, novel catalysts, good adsorbents, and colorimetric sensors. With continuing progress of enormous synthesis and applications of NPs, the risk of NPs on EHS (environmental, health and safety) was emerged. For example, it was well known that silver nanoparticles (AgNPs) with 1-10 nm of diameter attached to the surface of cell membrane and were able to penetrate, followed by rupturing. To analysis of PChem of AgNP, citrate-coated AgNP (<20 and <50 nm) was obtained from ABCnanotech (Korea), which was designated as OECD nanomaterials. We selected PChem-12 as key nano-properites; agglomeration/aggregation state, cystalline phase/crystallite size, representative TEM, size/size distribution, zeta potential/surface charge, surface chemistry, photocatalytic activity, dispersion stability in water, hydrolysis, octanol water partition coefficient, redox potential, and radical formation potential. PChem-12 was analyzed with HR-TEM, SEM, DLS, ELS, ICP, XRD, UV, Turbiscan, ISE, ORP meter, and so on. Among the PChem-12, representative TEM (PChem#3) and size/size distribution (PChem#4) was generally used in ca. 50% SCI-papers published from 2006 to 2010 year. However, key PChem affected on the in-vivo and in-vitro cytotoxicity of AgNPs was revealed as size, surface charge, and radical formation. In results, key metric for nanotoxicity is mentioned as aggregation or agglomeration state, which was easily influenced by ionic strength, salt, NOM, or some organics. Detail information for PChem-12 of AgNPs will be presented in poster-presentation.
9:00 PM - GG4.4
Toxicokinetic Study of Zinc Oxide Nanoparticles in Rats.
Soo-Jin Choi 1 , Hea-Eun Chung 1 , Miri Baek 1 , Jin Yu 1 Show Abstract
1 Food Science and Technology, Seoul Women's University, Seoul Korea (the Republic of)
ZnO nanoparticle is one of the most widely used engineered nanomaterials in commercial products due to its UV light absorption, antimicrobial, catalytic, semi-conducting, and magnetic properties. So, they are widely applied to personal care products, sunscreen, paints, electronic materials, rubber manufacture, food additives, and medicine. However, little information about toxicological effects of ZnO nanoparticles in vivo is actually available, and moreover, to the best of our knowledge, their toxicokinetic behavoirs in animal models were not evaluated yet. In this study, toxicokinetics of ZnO nanoparticles such as absorption, distribution, metabolism, and excretion after oral administration was investigated with respect to two different particle sizes (20 and 70 nm) in rats. The blood, tissues, urine, and feces were collected and Zn concentration was measured with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that kinetic parameters such as area under the plasma concentration time curve (AUC), maximum concentration (Cmax), and time to maximum plasma concentration (Tmax) differed with exposure concentration, but any significant effect of particle size was not seen. ZnO nanoparticles were determined to be absorbed and excreted through the kidney within 24 h up to the dose of 300 mg/kg without accumulation in any specific organs. These findings provide critical information about the toxicokinetic behaviors of ZnO nanoparticles as well as its potential toxicity in vivo.
9:00 PM - GG4.5
Acute Oral Toxicity and Toxicokinetic Studies of Inorganic Layered Nanoparticles.
Soo-Jin Choi 1 , Miri Baek 1 , Jin Yu 1 , Hae-Eun Chung 1 Show Abstract
1 Food Science and Technology, Seoul Women's University, Seoul Korea (the Republic of)
Inorganic layered double hydroxides (LDHs), also known as anionic nanoclays or hydrotalcite-like compounds, have attracted a great deal of interest for their potential as non-viral delivery carriers. LDHs can intercalate anionic molecules such as drugs, nucleotides, and biomolecules into the interlayer spaces, release them in a controlled manner, and eventually protect them against harsh biological conditions. In this study, the acute oral toxicity of LDH nanoparticles were assessed according to the OECD guideline 423 and their toxicokinetic behaviors such as absorption, distribution, and excretion were also evaluated in mice. No significant effects on behavior, body weight, and survival rate were observed up to the dose of 2000 mg/kg during 14 days. Serum biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), and uric acid (UA) did not significantly change, indicating that LDH nanoparticles did not acutely cause the liver or kidney injury. Plasma concentration of LDH nanoparticles rapidly decreased within 8 h depending on the exposure dose, but they did not accumulate in any specific organs. Excretion profiles showed that absorbed and non-absorbed LDH nanoparticles were rapidly excreted in the urine and feces, respectively, at early days of post-administration. These findings suggest that the present LDH nanoparticles do not exhibit the acute oral toxicity in mice and will be promising candidates for biological and pharmaceutical applications.
9:00 PM - GG4.6
Synthesis and Properties of Fe3O4/TiO2 Composite Magnetic Photocatalyst.
Jieying Jing 1 3 , Jing Li 1 3 , Qingbo Zhang 3 , Vicki L. Colvin 3 , Wenying Li 1 , William W. Yu 1 2 3 Show Abstract
1 Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan China, 3 Department of Chemistry, Rice University, Houston, Texas, United States, 2 State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun China
The use of magnetic nanoparticle is exploited as a promising and important approach in separating and recycling nanoparticles from treated wastewater in a slurry reactor. In this study, Fe3O4/TiO2 composites were synthesized by coating magnetite (Fe3O4) nanoparticles with titanium dioxide (TiO2) via modified sol-gel method. Transmission electron microscope (TEM), X-ray diffraction (XRD), and SQUID were used to characterize the as-prepared magnetic photocatalyst. The photocatalytic activity of the as-synthesized magnetic photocatalyst was tested by degrading Acid Orange 7 under UV illumination. Results show that the as-synthesized magnetic photocatalyst exhibits similar photocatalytic activity compared to commercial P25 TiO2 and it can be easily recovered from the treated solution by using a magnetic field, which will finally reduce the cost of wastewater treatment and possess the potential for industrial application.
9:00 PM - GG4.7
Synthesis of High Quality Water-Dispersible Anatase TiO2 Nanoparticles.
Jieying Jing 1 3 , Jing Li 1 3 , Qingbo Zhang 3 , Vicki L. Colvin 3 , Wenying Li 1 , William W. Yu 1 2 3 Show Abstract
1 Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan China, 3 Department of Chemistry, Rice University, Houston, Texas, United States, 2 State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun China
Synthesis of titanium dioxide (TiO2) with high crystallinity, better photocatalytic performance via easier approach is still a major topic until now. Herein TiO2 nanoparticles with a size of 10±2 nm have been synthesized under acid condition with a high water:alkoxide ratio at a low temperature of 80°C. This method not only harvested the water-dispersible anatase TiO2 but also eliminated the high-temperature calcination step needed in a typical sol-gel method, which is required to transform amorphous TiO2 into a photoactive crystalline phase. High-resolution transition electron microscopy (HRTEM), X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and BET surface area test were used to characterize the synthesized TiO2 nanoparticles. The photocatalytic performance of as-synthesized nanoparticles was evaluated by photocatalytic degradation of Acid orange 7 (AO). The as-synthesized TiO2 exhibited higher photocatalytic activity than TiO2 prepared by the typical sol-gel method and commercial Degussa P25, which may be attributed to its stable water-dispersibility, small size, high specific surface area and the high crystallinity.
9:00 PM - GG4.8
Effect of Dispersing Agents on Biological Evaluation of ZnO Nanoparticles.
Hae-Eun Chung 1 , Seung-Eun Lee 1 , Hye-Jin Koo 1 , Soo-Jin Choi 1 Show Abstract
1 Department of Food Science and Technology, Seoul Women's University, Seoul Korea (the Republic of)
Nanomaterials have been extensively applied to industrial fields and human-related products. Among various inorganic materials, metal oxide nanoparticles have attracted much attention due to their high mechanical, thermal, and chemical stability. In particular, zinc oxide (ZnO) is characterized by photocatalytic ability, photo-oxidizing capacity, ultraviolet (UV) light absorption, and semi-conducting or magnetic properties, leading to wide applications in ceramics, cement, sealant, adhesive, catalyst, food additive, and sunscreen products. In order to apply ZnO nanoparticles in biological fields, they should be well dispersed in solution where some excipients or dispersing agents need to be added for better stabilization. However, the excipients or dispersing agents can also affect the cellular response, uptake, and toxicity of ZnO nanoparticles, which may mislead to interpret whether positive or negative effects are caused by dispersing agents or nanomaterial itself. In the present study, therefore, we investigated the effects of ZnO nanoparticles dispersed in different agents such as citrate and carboxymethyl cellulose (CMC) on cytotoxicity and cellular uptake in human lung cell lines, by evaluating cell proliferation, membrane damage, and internalized uptake amount. We also compared the cellular response of the dispersed ZnO nanoparticles with those prepared in water without any dispersant as well. Furthermore, the plasma concentration of the dispersed ZnO nanoparticles was assessed after oral administration in rats to obtain kinetic parameters which indicate their absorption and excretion behaviors. The results demonstrated that the cytotoxicity, cellular uptake, and kinetic behaviors of ZnO nanoparticles strongly depend on dispersing agent types, suggesting that more careful caution should be needed to choose appropriate dispersants of nanomaterials, especially for biological evaluation.