1USEPA Office of Research and Development, National Exposure Research Laboratory, USA
2National Research Council Research Associate, USA
3Student Services Contractor, USA
Anticipated applications and production volumes of engineered nanomaterials (ENMs) have raised concerns about ENM release and potential adverse effects in the environment. Laboratory studies have demonstrated the impact of commercial surfactants and naturally occurring dissolved organic carbon (DOC) on the stability of multiwalled carbon nanotubes (MWCNTs) in aqueous suspensions. While these studies have demonstrated the efficacy of surfactants and DOC on stabilizing MWCNTs, it is unclear how these surface active agents operate in more complex systems. For example, a reasonable scenario for MWCNT release to the environment is where MWCNTʼs have been stabilized in suspension with the use of commercial surfactants and then accidentally released into a waterway as surfactant-wrapped MWCNTs where they interact with naturally occurring surfactant-like DOC. Studies have also indicated that graphene oxide (GO), an important member of the graphene family of nanomaterials, is physically stable in the water column but may undergo phototransformation yielding a wide array of transformation products with differing transport and biomarker response characteristics. In this presentation we report on EPA/ORD in-house research with MWCNTs and GO in these key research areas: 1) suspension and stability in the water column, with a focus on the influence of ionic strength and naturally occurring DOC; 2) attachment to surfaces using model (quartz crystal microbalance sensors) and environmental surfaces (sediments); 3) biomarkers of ENM exposure utilizing model cell membranes and metabolomics techniques; 4) phototransformations in the aquatic environment; and 5) modeling exposure in surface waters using the Water quality Analysis Simulation Program (WASP8) updated with particle attachment kinetic parameters.
Biography:
Dr. Dermont Bouchard has 30+ years of experience at USEPA where his research focuses on contaminant transport and fate in the environment. Currently Dr. Bouchard is a Project Leader for Engineered Nanomaterials (ENMs) research where his responsibilities include strategic (EPA/ORD-wide planning for nanomaterials environmental fate research) and tactical (principal investigator for carbon nanotubes and graphene family materials transport and eco-exposure research) planning and research in support of EPAʼs national program Chemical Safety for Sustainability. Key research interests are ENM interactions with model and naturally occurring surfaces, transport in surface waters, and development of functional assays for ENM attachment, transformation, and biomarker response in support of ENM aquatic exposure model parameterization.
1Institute of Polymer Mechanics, Latvia
2Riga Technical University, Latvia
A loaded material surface that interrupts a continuum is a mechanical stress concentrator. Therefore atomic/molecular couples situated at the surface nanolayer could be overloaded and destructed. These strongly result the material exploiting capacity under chemical and microbiological environment conditions. Dilatation and destruction of the couples alters the surface potential barrier (PB) that an electron excited by an external source is able to leave. In this respect the electron emission (EE) of the loaded material is able to indicate its overloading/destruction.
A carbon nanotube-reinforced epoxy composite (NREC) that is characterized with high strength-to-weight ratio has a wide perspective for aerospace, automotive, civil engineering, etc technical applications. However, a knowledge about NREC surface processes induced by mechanical loading that overload/destroy atomic/molecular couples is very poor.
The research is directed to in situ explore EE induced by axial loading of NREC. The specimens prepared for the central axial loading as typically were loaded at the vacuum 10-4 Pa. The specimens had a concentration of the carbon nanotubes (CNT) in a range 0…1.0%. The EE was detected alongside with loading. The EE was excited by the ultraviolet photons. Their energy was selected to be close to the PB. As the result an energy of the exited electrons was around 5eV and therefore they emitted just from the NREC surface nanolayer with a thickness ~ 10 nm. A secondary electron multiplier was to detect electrons, their current being was around > 10-17 …10-16 A.
The experiments demonstrated that EE depended nonlinearly on the elastic strain extended from 0 to 2%. Several maxima of EE current were detected that evidenced about excitation/damaging of surface atomic-molecular couples. The first maximum displayed at ~ 0.3 % of strain and was identified as delivered from the epoxy binder. The EE current decreased around 10 times with raising of the CNT concentration in the above range. This indicated increasing of PB, the latter relating to the elasticity module. Growth of CNT concentration increased elasticity module and induced the EE maximum at ~ 1.2% of strain (~60 % of the strength).
The results achieved are in favor that EE is the effective instrument to explore NREC surface nano layer destruction induced by the elastic deformation.
Acknowledgement: The research leading to the above results has received the funding from Latvia state research programme under grant agreement “INNOVATIVE MATERIALS AND SMART TECHNOLOGIES FOR ENVIRONMENTAL SAFETY, IMATEH”.
Biography:
Prof. Yuri Dekhtyar has the expertise to functionalize and characterize nanoobjects and nanostructured materials. He is the leader in prethreshold electron and exoelectron spectroscopy. Has around 450 publications, leaded a number of the international and national projects. Head of the Institute of Biomedical Engineering and Nanotechnologies of the Riga Technical University, Latvia; Latvian State Prize winner; full member of the of the Latvian Academy of Sciences; member of national and international societies. Organized several international conferences, delivered a number of the invited lectures at the meetings and universities around the world. Contributed to the education of hundreds BSc, MSc students both at the home and internationally hosting universities. Supervised a number of PhD students.
The Hong Kong University of Science & Technology, Hong Kong
Nanomaterials play an important role in the treatment of water and wastewater. Metal oxides based nanomaterials such asγ-Fe2O3 and Fe3O4 based magnetic nanoparticles and core-shell Fe3O4@SiO2 structure magnetic nano-photocatalysts have been widely investigated for the removal and recovery of toxic contaminants from aqueous solutions because of their high surface area to volume ratio, high physic-chemical stability, biocompatibility, and efficient regeneration of spentnanoadsorbents. The magnetic nanomaterials can be characterized using X-ray diffractometer (XRD) for crystal identification, transmission electron microscopy (TEM) for size and morphology investigation, BET analyzer for surface area measurement, and vibrating sample magnetometer (VSM) for magnetic property and behavior analysis.
Surface and subsurface watercontamination has created great attention of environmental scientists and engineers to eliminate toxic contaminantsfrom wastewater before discharging into water bodies. Nowadays, it has become a hot topic to develop novel nanoscale adsorbent materials for the removal of toxic dyes, heavy metal and persistent organic pollutant (POP) under varying experimental conditions. Adsorption-desorption or photocatalytic degradation of pollutants from aqueous media to the interface of nanoadsorbents have been investigated to understand the contaminant removal performance using isotherm equations and kinetic sorption rate and to determine their removal mechanisms using FTIR, XPS and surface complexation modeling. In this presentation, recent advances in toxic dyes, heavy metal and POP removal from water and wastewater by magnetic nanoparticles and magnetic nano-photocatalystswill be presented in regards to their synthesis, characterization, applications and limitation. In order to further examine the compatibility of thesenovel magnetic sorbents in industrial application, a novel prototype flow-through treatment system through the combination of an electro-magnetic separation unit, and magnetic nanoparticles based contaminant removal process, including sorption, desorption, recovery and regeneration of the magnetic sorbents will be presented.
Biography:
Prof. Irene M. C. Lo is full professor at the Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology (HKUST). She is an elected Academician of European Academy of Sciences and Arts (EASA), elected Fellow of Hong Kong Institution of Engineers (FHKIE) and American Society of Civil Engineers (FASCE). Her Ph.D. (1992) is in Civil (Environmental) Engineering from University of Texas, Austin. She is Adjunct Professor of Tongji University, Tianjin University, Jilin University and Harbin Institute of Technology in China. She had been Visiting Professor at Technical University of Denmark and University of Wisconsin, Madison. She was the recipient of 2004 ASCE James Croes Medal, 2007 ASCE Samuel Arnold Greeley Award, 2008 EWRI Best Practice-Oriented Paper Award, 2009 ASCE Wesley W Horner Award and 2012 ASCE EWRI Best Practice-Oriented Paper Award. She has 2 patents, edited 7 technical books, and published over 260 SCI journal articles and conference papers with about 4500 citations and H-index of 35. Her research areas include remediation technologies for river sediment, contaminated soils and groundwater; magnetic nano- and microparticles for environmental pollution control; pollutant migration in soils; and waste treatment and management.
College of Pharmacy, Seoul National University, Korea
Introduction: Silver nanoparticles have attracted great attention due to their enhanced antibacterial properties arising from larger surface area per volume compared to silver ion. The moisturizing effect inherent to silver nanoparticles also contributes greatly to its use as a topical antibacterial agent for wound healing. The antibacterial property of silver nanoparticles provides topical wounds with an indirect environment for healing by the prevention of pathogenic infection. However, the direct wound-healing effects of silver nanoparticles have not been explored until now. The wound healing involves a number of complex processes such as epithelialization. Although antibacterial effect on wounded skin provides a suitable environment for epithelialization to occur, it does not accelerate epithelialization directly. In order for silver nanoparticles to be a more powerful topical therapeutic agent, it is necessary to have a direct wound healing activity in addition to antibacterial effect. In this work, we report a bimodal therapeutic silver nanoparticle that possesses both direct wound-healing and antibacterial properties.
Results: The synthetic nanoparticles consisted of high-valent silver-pyridoxine complexes to achieve bi-functional therapeutic activities of both antibacterial and proliferative property. An MAPK pathway study proved that silver nanoparticle induced proliferation and migration to keratinocyte and fibroblast cells. Antibacterial activities in 10 different pathogenic bacteria responsible for the infection of burn wound were tested. Its wound-healing efficacy was verified through diabetic mice as well as in vitro assay. Faster wound healing occurring on the skin wound of diabetic mice attested great potential of bimodal therapeutic silver nanoparticles as a next-generation topical therapeutic agent.
Conclusions: From the scrape assay and signaling pathway study, it is clear that silver-pyridoxine nanoparticle accelerates the proliferation and migration of fibroblast and keratinocyte cells. Silver-pyridoxine nanoparticle promotes the process of wound healing in diabetic mice. These wound healing efficacies, along with the antibacterial and moisturizing properties inherent to SPN, are expected to pave the way for next-generation topical silver nanotherapeutic agents.
Biography:
Prof. Joon Myong Song received his Ph.D. in 1997 at Kyushu University, in Japan. He worked as a postdoctoral research fellow from 1998 to 2004 at Iowa State University, Brookhaven National Laboratory, and Oak Ridge National Laboratory in United States. At present he is a professor and head of Department of Pharmacy at College of Pharmacy, Seoul National University in South Korea. His research area includes multifunctional nanoparticle for diagnosis and therapy and high-content cell-based drug screening and diagnosis using hyper-multicolor cellular imaging. He has published 87 peer reviewed papers in the top journals, 7 book chapters, and 10 patents.
1Materials Science and Engineering, University of Maryland, USA
2Institute for Advanced Materials, Rutgers University, USA
3Physics, Auburn University, USA
4Chemistry and Biochemistry, University of Maryland, USA
5U.S. Army Research Laboratory, USA
The interface between 4H-SiC and SiO2 in metal oxide semiconductor field effect transistor (MOSFET) devices contains a high density of electrically active defects even though the interface is very sharp. The defects adversely affect the performance of microelectronic devices by lowering the electron mobility at the interface compared to that of bulk SiC. Furthermore, the charge mobility of these devices is greatly affected by the process used for deposition, or growth, of the oxide as well as any post oxidation process. The most prevalent treatment is a nitric oxide (NO) post-anneal which gives rise to increase in the interface mobility. In addition, devices fabricated on different crystallographic faces of SiC, or with varying miscut at the interface show markedly different electronic performance. Post oxidation annealing in NO has shown improved channel mobility, increased N interfacial density, and decreased charged interface trap density. We present a systematic analysis of the chemistry and structure of the oxide/SiC interface by monitoring the change in the fine structure of the Si-L2,3, C-K and O-K edges in the electron energy loss spectra within a few nanometers of the interface of devices processed by different methods. Our results indicate that the Si-L2,3, C-K and O-K change at the interface indicating a different chemical structure within this region.
*Supported by ARL under Grants No. W911NF-11-2-0044 and W911NF-07-2-0046, and NSF GRFP Grant No. DGE 1322106
Biography:
Lourdes Salamanca-Riba is a Professor in the Materials Science and Engineering Department at the University of Maryland. Her research is in the areas of nanomaterials, self-assembly in semiconductor nanostructures, hybrid photovoltaics, solid oxide fuel cells and carbon nanostructures in metals called covetics. Her research focus is on the synthesis and characterization of materials using transmission electron microscopy. She has a BS degree in Physics from the Universidad AutónomaMetropolitana in Mexico City and a PhD degree also in Physics from MIT. She was a Senior Research Scientist at the GM Research Laboratory in Warren, MI prior to becoming a faculty member at the University of Maryland. Professor Salamanca-Riba has over 140 publications and is a member of the Materials Research Society, American Physical Society and the Microscopy Society of America.
Louisiana Tech University, Biomedical Engineering and Institute for Micromanufacturing, USA
We have recently reported the novel synthesis of a scalable nano-biocomposite containing copper and the amino acid dimer cystine. The biocomposites were synthesized at physiological temperature (37 degrees Celsius) and in a liquid medium, with typical synthesis time of 3-7 hours. Two copper sources successfully resulted in biocomposites: copper nanoparticles (CuNPs), and copper sulfate. Both copper sources resulted in very high-aspect ratio structures (HARS), with diameters scaling from 20 nm to a few microns, and lengths scaling from hundreds of nanometers to hundreds of microns as determined by scanning and transmission electron microscopy and white-light microscopy. Synthesis using copper sulfate resulted in “cleaner” synthesis in that the copper sulfate went fully into solution, while the CuNPs often were not fully transformed during the synthesis. Once synthesized, the HARS were remarkably stable, for at least a year in both liquid (water) and dried form. Furthermore, they had very low agglomeration (clumping), which made transfer and concentration of the HARS by centrifugation much more feasible. While length of the individual HARS could not be controlled during the synthesis, post-synthesis the average length could be decreased using sonication. Furthermore, solutions at extreme pH values (both basic and acidic), were able to degrade the HARS post synthesis. While starting CuNPs were very toxic to cells in vitro at 25-50 micrograms per ml, including to brain tumor cells, the CuNP- and copper sulfatederived HARS were much less toxic on a per mass basis as determined by the MTT metabolic assay. Additionally, we found that over time the copper containing HARS could be degraded in cell culture conditions, bound to phagocytic cells of the brain (microglia), and could be taken up by 3-dimensional (3D) cell spheroids. Thus, these novel nano- and micro-biocomposites containing copper and cystine could provide a degradable platform for directing cell engineering including destruction of cancer cells. Since these biocomposites are formed under physiological conditions and include the amino acid dimer cystine, they may be more amenable to functionalization and utilization in 2D and 3D cell systems for both short-term and long-term cell engineering.
Biography:
Dr. DeCoster is the James E. Wyche III endowed Associate Professor in Biomedical Engineering at Louisiana Tech University in Ruston, Louisiana and is a member of the Institute for Micromanufacturing there. He received his Ph.D. in Biochemistry and Molecular Biophysics from the Medical College of Virginia/ Virginia Commonwealth University, and his B.S. in Biology from the College of William and Mary. His research interests include combining nanotechnology with cell biology to understand the brain and disease states such as cancer. In 2010 Dr. DeCoster founded Nanogaia, a startup company developing novel nano-biological hybrid materials and interfaces for cells in 2D and 3D environments. Dr. DeCoster has published over 65 peer-reviewed papers with over 1,950 citations of this work. He has served extensively as a reviewer for the National Institutes of Health and the National Science Foundation, and his lab group is currently funded by multiple federal and state grant awards.
1Capacitor Sciences Inc., USA
2Department of Physics, Queens College of CUNY, USA
3The Graduate Center of CUNY, USA
Efficient energy storage is the key component in the development of various modern technologies. In the present time, the all-electric cars start to enter the vehicle market but they are still more expensive and less trustworthy than the usual ones. Electronic devices, which are omnipresent in modern society, are also heavily dependent on reliable energy storage modules. Moreover, renewable energy sources such as solar cells and wind turbines are sustainable and environmentally friendly, but their energy production is intermittent and the effective storage would make the energy available on demand. Available market for energy storage devices is expected to exceed $1000B. As the limitations of the electrochemical batteries are impossible to overcome, the right answer should arrive from the capacitor side. In the present time capacitors are cheap and have very high power density. To make them competitive with the batteries, their energy density should be increased.
The energy density stored in the capacitor is proportional to the applied voltage squared with the proportionality coefficient determined by the permittivity of the material inside the capacitor. Correspondingly, large values of the energy density can be achieved by using composite polymer materials with the permittivity increasing with the voltage. This can be especially efficient at high operational voltages. In this talk we discuss an approach to use a specific class of polymers to develop capacitors having extremely high energy density. These polymers display interesting polarization dependencies on the electric field. It is possible to perform crafty molecular engineering to achieve necessary phenomenology. We believe that the proposed approach ushers a new generation of the energy storage devices providing the solutions to the many needs of the society.
Biography:
Pavel Lazarev is the inventor of Capacitor Sciencesʼ high permittivity technology and founder of the Company. He also is the founder of Cryscade and inventor of the companyʼs Donor-Bridge-Acceptor technology. He received his Masters from Moscow State University, Ph.D. in Crystallography and Dr. of Science Degree in Biophysics from the Russian Academy of Science. Previously, Pavel founded Nanotechnology MDT (www.nt-mdt.com), Akvion (www.akvion.ru), Optiva Inc., Ribtan Inc. (www.ribtan.com) and Crysoptix KK, (www.crysoptix.com). Pavel was an editor of International Journals ‘Molecular Engineeringʼ, ‘Nanobiologyʼ and ‘Molecular Materialsʼ. Pavel has published several books, over 150 technical publications and over 200 inventions with emphasis on the R&D and production of functional crystalline films based upon coatable lyotropic liquid crystals.
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