Center for Sustainable Nanotechnology

Singapore, Singapore

Center for Sustainable Nanotechnology

Singapore, Singapore

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PubMed | Center for Sustainable Nanotechnology and National University of Singapore
Type: | Journal: Indoor air | Year: 2016

We investigated the physicochemical properties (size, shape, elemental composition, and endotoxin) of size resolved particulate matter (PM) collected from the indoor and corridor environments of classrooms. A comparative hazard profiling of these PM was conducted using human microvascular endothelial cells (HMVEC). Oxidative stress-dependent cytotoxicity responses were assessed using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and high content screening (HCS), and disruption of monolayer cell integrity was assessed using fluorescence microscopy and transwell assay. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) analysis showed differences in the morphology and elemental composition of PM of different sizes and origins. While the total mass of PM collected from indoor environment was lower in comparison with those collected from the corridor, the endotoxin content was substantially higher in indoor PM (e.g., ninefold higher endotoxin level in indoor PM


News Article | October 26, 2016
Site: www.eurekalert.org

Chemists at the University of Iowa will research the effects of nanomaterials on the environment and human health using a network of supercomputers funded by the U.S. National Science Foundation. Sara E. Mason, assistant professor in the Department of Chemistry, won an NSF award that grants her team access to the Extreme Science and Engineering Discovery Environment (XSEDE). The XSEDE project links computers, data, and people from around the world to establish a single, virtual system that scientists can interactively use to conduct research. It was started in 2011 and was renewed by the NSF last August. The NSF says it "will be the most advanced, powerful, and robust collection of integrated advanced digital resources and services in the world." The UI grant, valued at $72,503, essentially gives Mason's team time on the supercomputer network, which they can access from their desktops. The researchers will use that time to study nanoparticles--matter far too small to be seen by the naked eye and present in a range of products, from sunscreen to advanced batteries for hybrid and electric vehicles. The team hopes to better define the atom-to-atom interactions of various nanoparticles. Mason says the grant will "super charge" her computational research. "To me, having four concurrent NSF research grants is a big deal, and now, having the boost of the computer time allows us to do even more," Mason says. "XSEDE allows us to run simulations using quantum mechanics and highly parallelized computers. The outcome is new chemical insight into natural or widely used nanoparticles. We can then connect the chemistry to broader issues, such as human health and the behavior of nanomaterials in the environment." Mason's group aims to find and design nanomaterials that are more benign to the environment and human health. Part of the search means trying out new elements in computational designs to find out how they interact, as well as their side effects, good or bad. The XSEDE computers will give them far more computing horsepower to carry out those computational experiments. "We can collectively get a lot more done in a shorter period of time," says Joseph Bennett, co-principal investigator on the grant and a post-doctoral researcher in Mason's group. The UI is one of 15 institutions affiliated with the NSF-funded Center for Sustainable Nanotechnology, devoted to investigating the fundamental molecular mechanisms by which nanoparticles interact with biological systems.


Gupta N.,Wageningen University | Fischer A.R.H.,Wageningen University | George S.,Center for Sustainable Nanotechnology | Frewer L.J.,Newcastle University
Journal of Nanoparticle Research | Year: 2013

The introduction of different applications of nanotechnology will be informed by expert views regarding which (types of) application will be most societally acceptable. Previous research in Northern Europe has indicated that experts believe that various factors will be influential, predominant among these being public perceptions of benefit, need and consumer concern about contact with nanomaterials. These factors are thought by experts to differentiate societal acceptance and rejection of nanotechnology applications. This research utilises a larger sample of experts (N = 67) drawn from Northern America, Europe, Australasia, India and Singapore to examine differences in expert opinion regarding societal acceptance of different applications of nanotechnology within different technological environments, consumer cultures and regulatory regimes. Perceived risk and consumer concerns regarding contact with nano-particles are thought by all experts to drive rejection, and perceived benefits to influence acceptance, independent of country. Encapsulation and delivery of nutrients in food was thought to be the most likely to raise societal concerns, while targeted drug delivery was thought most likely to be accepted. Lack of differentiation between countries suggests that expert views regarding social acceptance may be homogenous, independent of local contextual factors. © 2013 Springer Science+Business Media Dordrecht.


News Article | December 6, 2016
Site: www.cemag.us

Currently, most bioplastics are produced using renewable biomass resources, such as vegetable fats, oils, and sweet potatoes, which readily decompose once they are buried in the ground. However, these materials lack the necessary strength and flexibility required to extend the life of plastics in the packaging and electronic industry. To date, there have been limited successes in inventing new solvents to dissolve cellulose for commercialization usage. Also, the increase in toxicity associated with current dissolution techniques has made cellulose less attractive for use in the plastic industry. But, Tuskegee University researchers have discovered a new method that can be used to suspend tiny particles of cellulose in an organic solvent that is commonly used in the plastic industry. This technique could remove the current limitations and allow for the creation of a new kind of biodegradable cellulose-based plastic. This product can be used in the production of items ranging from packaging materials to plastic covers. Dr. Michael L. Curry, an Associate Professor in the Department of Chemistry and Associate Adjunct Professor in the Department of Materials Science and Engineering, along with his second-year graduate student, Donald H. White, both work as members of and in collaboration with the National Science Foundation (NSF) funded Center for Sustainable Nanotechnology (Phase II), a multi-institutional partnership devoted to investigating the fundamental molecular mechanisms by which nanoparticles interact with biological systems. Taking full advantage of the new dispersion of cellulose technique, Curry and White experimented with the development of cellulose-based plastics using both biodegradable and non-biodegradable polymer matrices. Unlike earlier bio-based plastics, their cellulose-based plastics are flexible and show significant improvements in the storage modulus which demonstrates an increase in the rigidity and strength of the composite material. Curry states that, given that the global production of plastics will exceed 300 million tons annually in the near future and greater than 98 percent of it is made with crude oil and other fossil fuels, this new invention will not only help us to meet our Center’s goal of “using fundamental chemistry to enable the development of nanotechnology in a sustainable manner, for societal benefits,” but will also limit the amount of non-biodegradable plastics ending up in our land fields and oceans, and the amount of carbon dioxide released into the atmosphere by plastics that contribute to global climate change. “This discovery will allow us to develop new and better plastic products, use plastic resources more efficiently and create products that have a low impact on the environment, thus reducing our ecological footprint,” Curry says.


Xiong S.,Nanyang Technological University | George S.,University of California at Los Angeles | George S.,Center for Sustainable Nanotechnology | Yu H.,Nanyang Technological University | And 4 more authors.
Archives of Toxicology | Year: 2013

The aim of this study is to uncover the size influence of poly (lactic-co-glycolic acid) (PLGA) and titanium dioxide (TiO2) nanoparticles on their potential cytotoxicity. PLGA and TiO2 nanoparticles of three different sizes were thoroughly characterized before in vitro cytotoxic tests which included viability, generation of reactive oxygen species (ROS), mitochondrial depolarization, integrity of plasma membrane, intracellular calcium influx and cytokine release. Size-dependent cytotoxic effect was observed in both RAW264.7 cells and BEAS-2B cells after cells were incubated with PLGA or TiO2 nanoparticles for 24 h. Although PLGA nanoparticles did not trigger significantly lethal toxicity up to a concentration of 300 μg/ml, the TNF-α release after the stimulation of PLGA nanoparticles should not be ignored especially in clinical applications. Relatively more toxic TiO2 nanoparticles triggered cell death, ROS generation, mitochondrial depolarization, plasma membrane damage, intracellular calcium concentration increase and size-dependent TNF-α release, especially at a concentration higher than 100 μg/ml. These cytotoxic effects could be due to the size-dependent interaction between nanoparticles and biomolecules, as smaller particles tend to adsorb more biomolecules. In summary, we demonstrated that the ability of protein adsorption could be an important paradigm to predict the in vitro cytotoxicity of nanoparticles, especially for low toxic nanomaterials such as PLGA and TiO2 nanoparticles. © 2012 Springer-Verlag.


Xiong S.,Nanyang Technological University | George S.,University of California at Los Angeles | George S.,Center for Sustainable Nanotechnology | Ji Z.,University of California at Los Angeles | And 6 more authors.
Archives of Toxicology | Year: 2013

To uncover the size influence of TiO2 nanoparticles on their potential toxicity, the cytotoxicity of different-sized TiO2 nanoparticles with and without photoactivation was tested. It was demonstrated that without photoactivation, TiO2 nanoparticles were inert up to 100 lg/ml. On the contrary, with photoactivation, the toxicity of TiO2 nanoparticles significantly increased, which correlated well with the specific surface area of the particles. Our results also suggest that the generation of hydroxyl radicals and reactive oxygen species (ROS)- mediated damage to the surface-adsorbed biomolecules could be the two major reasons for the cytotoxicity of TiO2 nanoparticles after photoactivation. Higher ROS generation from smaller particles was detected under both biotic and abiotic conditions. Smaller particles could adsorb more proteins, which was confirmed by thermogravimetric analysis. To further investigate the influence of the generation of hydroxyl radicals and adsorption of protein, poly (ethylene-alt-maleic anhydride) (PEMA) and chitosan were used to coat TiO 2 nanoparticles. The results confirmed that surface coating of TiO2 nanoparticles could reduce such toxicity after photoactivation, by hindering adsorption of biomolecules and generation of hydroxyl radical (OH) during photoactivation. © The Author(s) 2012.


News Article | February 4, 2016
Site: www.greencarcongress.com

« Change in magnesium alloy microstructure changes corrosion resistance and improves potential for transportation applications | Main | President Obama proposes 50% increase in spending on clean transportation, funded by $10/barrel tax on oil » Nanoparticle nickel manganese cobalt oxide (NMC), an emerging material that is being rapidly incorporated into lithium-ion battery cathodes, has been shown to impair Shewanella oneidensis, a key soil bacterium, according to new research published in the ACS journal Chemistry of Materials. The study by researchers at the University of Wisconsin—Madison and the University of Minnesota is an early signal that the growing use of the new nanoscale materials used in the rechargeable batteries that power portable electronics and electric and hybrid vehicles may have unforeseen environmental consequences. Nickel manganese cobalt oxide (NMC) is a class of lithium intercalation compounds with the composition Li Ni Mn Co O (0 For the study, the team used Li Ni Mn Co O (with x=1 corresponding to fully lithiated materials) due to its widespread use. The genus Shewanella comprises Gram-negative bacteria that are distributed globally; Shewanella oneidensis MR-1 plays an important role in the cycling of metals in the environment and is a model system for environmental studies. The study characterized the influence of NMC nanoparticles on S. oneidensis population growth and respiration, and linked these with corresponding changes in solution composition and NMC surface composition via X-ray photoelectron spectroscopy. Subjected to the particles released by degrading NMC, the bacterium exhibited inhibited growth and respiration. The researchers found that NMC nanoparticles in aqueous media under partial incongruent dissolution preferentially released Li+ and the transition metals Ni2+ and Co2+ into solution and left behind chemically transformed nanoparticles that are depleted in Ni and enriched in Mn. They demonstrated that the toxicity of NMC arises from the release of the transition metal ions in solution rather than the remaining transformed nanoparticles. Hamers collaborated with the laboratories of University of Minnesota chemist Christy Haynes and UW–Madison soil scientist Joel Pedersen to perform the new work. Haynes noted that “it is not reasonable to generalize the results from one bacterial strain to an entire ecosystem, but this may be the first ‘red flag’ that leads us to consider this more broadly.” According to Hamers, one big challenge will be keeping old lithium-ion batteries out of landfills, where they will ultimately break down and may release their constituent materials into the environment. Our results suggest that NMC entering aqueous environments (e.g., resulting from battery disposal into landfills) may act as a source of dissolved nickel and cobalt, potential bacterial toxicants, as well as other ions such as Mn and Li. This work provides additional motivation for efforts to develop and implement effective recycling strategies for lithium ion batteries. We suggest that by reducing dissolution of metals from NMC, its toxicity to bacteria and other organisms in natural environments can be reduced. Ultra-thin (~1 nm thickness) surface coatings of Al O and other stable oxides have been shown to reduce the reactivity of NMC cathodes and thereby improve the performance of NMC- containing lithium-ion batteries. Such coatings of water-stable oxides might also play an important role in mitigating the potential for environmental impact of NMC and related complex oxides. Data for Al O dissolution suggests that at pH ~6 a 1 nm thick coating would require on the order of one year to dissolve. This suggests that surface coatings may also have an important role in the environmental impact of NMC and other complex oxides. The group, which conducted the study under the auspices of the National Science Foundation-funded Center for Sustainable Nanotechnology at UW–Madison, also plans to study the effects of NMC on higher organisms.


News Article | February 7, 2016
Site: www.nanotech-now.com

Abstract: The material at the heart of the lithium ion batteries that power electric vehicles, laptop computers and smartphones has been shown to impair a key soil bacterium, according to new research published online in the journal Chemistry of Materials. The study by researchers at the University of Wisconsin-Madison and the University of Minnesota is an early signal that the growing use of the new nanoscale materials used in the rechargeable batteries that power portable electronics and electric and hybrid vehicles may have untold environmental consequences. Researchers led by UW-Madison chemistry Professor Robert J. Hamers explored the effects of the compound nickel manganese cobalt oxide (NMC), an emerging material manufactured in the form of nanoparticles that is being rapidly incorporated into lithium ion battery technology, on the common soil and sediment bacterium Shewanella oneidensis. "As far as we know, this is the first study that's looked at the environmental impact of these materials," says Hamers, who collaborated with the laboratories of University of Minnesota chemist Christy Haynes and UW-Madison soil scientist Joel Pedersen to perform the new work. NMC and other mixed metal oxides manufactured at the nanoscale are poised to become the dominant materials used to store energy for portable electronics and electric vehicles. The materials, notes Hamers, are cheap and effective. "Nickel is dirt cheap. It's pretty good at energy storage. It is also toxic. So is cobalt," Hamers says of the components of the metal compound that, when made in the form of nanoparticles, becomes an efficient cathode material in a battery, and one that recharges much more efficiently than a conventional battery due to its nanoscale properties. Hamers, Haynes and Pedersen tested the effects of NMC on a hardy soil bacterium known for its ability to convert metal ions to nutrients. Ubiquitous in the environment and found worldwide, Shewanella oneidensis, says Haynes, is "particularly relevant for studies of potentially metal-releasing engineered nanomaterials. You can imagine Shewanella both as a toxicity indicator species and as a potential bioremediator." Subjected to the particles released by degrading NMC, the bacterium exhibited inhibited growth and respiration. "At the nanoscale, NMC dissolves incongruently," says Haynes, releasing more nickel and cobalt than manganese. "We want to dig into this further and figure out how these ions impact bacterial gene expression, but that work is still underway." Haynes adds that "it is not reasonable to generalize the results from one bacterial strain to an entire ecosystem, but this may be the first 'red flag' that leads us to consider this more broadly." The group, which conducted the study under the auspices of the National Science Foundation-funded Center for Sustainable Nanotechnology at UW-Madison, also plans to study the effects of NMC on higher organisms. According to Hamers, the big challenge will be keeping old lithium ion batteries out of landfills, where they will ultimately break down and may release their constituent materials into the environment. "There is a really good national infrastructure for recycling lead batteries," he says. "However, as we move toward these cheaper materials there is no longer a strong economic force for recycling. But even if the economic drivers are such that you can use these new engineered materials, the idea is to keep them out of the landfills. There is going to be 75 to 80 pounds of these mixed metal oxides in the cathodes of an electric vehicle." Hamers argues that there are ways for industry to minimize the potential environmental effects of useful materials such as coatings, "the M&M strategy," but the ultimate goal is to design new environmentally benign materials that are just as technologically effective. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Kathawala M.H.,Nanyang Technological University | Xiong S.,Nanyang Technological University | Richards M.,Center for Sustainable Nanotechnology | Ng K.W.,Nanyang Technological University | And 2 more authors.
Small | Year: 2013

The rising production of nanomaterial-based consumer products has raised safety concerns. Testing these with animal and other direct models is neither ethically nor economically viable, nor quick enough. This review aims to discuss the strength of in vitro testing, including the use of 2D and 3D cultures, stem cells, and tissue constructs, etc., which would give fast and repeatable answers of a highly specific nature, while remaining relevant to in vivo outcomes. These results can then be combined and the overall toxicity predicted with relative accuracy. Such in vitro models can screen potentially toxic nanomaterials which, if required, can undergo further stringent studies in animals. The cyto- and phototoxicity of some high-volume production nanomaterials, using in vitro models, is also reviewed. In vivo assessment on the safety of nanomaterials, though the gold standard, is extremely resource intensive, thus rendering this approach economically unviable. Conventional in vitro models, though fast and highly economical, do not perfectly mimic real-life situations. This review delves into emerging in vitro techniques that could bridge the gap between in vivo and in vivo studies, thereby balancing between resource usage and relevance to real-life situations. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Frewer L.J.,Northumbria University | Gupta N.,Wageningen University | George S.,Center for Sustainable Nanotechnology | Fischer A.R.H.,Wageningen University | And 3 more authors.
Trends in Food Science and Technology | Year: 2014

The literature on public perceptions of, and attitudes towards, nanotechnology used in the agrifood sector is reviewed. Research into consumer perceptions and attitudes has focused on general applications of nanotechnology, rather than within the agrifood sector. Perceptions of risk and benefit associated with different applications of nanotechnology, including agrifood applications, shape consumer attitudes, and acceptance, together with ethical concerns related to environmental impact or animal welfare. Attitudes are currently moderately positive across all areas of application. The occurrence of a negative or positive incident in the agri-food sector may crystallise consumer views regarding acceptance or rejection of nanotechnology products. •Acceptance of agrifood nanotechnology based on perceptions of risk, benefit and ethics.•Attitudes towards nanotechnology in general are currently moderately positive.•Occurrence of a major nanotechnology-related "event" may crystallise consumer attitude. © 2014 Elsevier Ltd.

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