Time filter

Source Type

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. Source

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. Source

« 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.

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. Source

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. Source

Discover hidden collaborations