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Harper S.L.,Oregon State University | Harper S.L.,Oregon Nanoscience and Microtechnologies Institute | Carriere J.L.,Oregon State University | Carriere J.L.,Oregon Nanoscience and Microtechnologies Institute | And 9 more authors.
ACS Nano | Year: 2011

The challenge of optimizing both performance and safety in nanomaterials hinges on our ability to resolve which structural features lead to desired properties. It has been difficult to draw meaningful conclusions about biological impacts from many studies of nanomaterials due to the lack of nanomaterial characterization, unknown purity, and/or alteration of the nanomaterials by the biological environment. To investigate the relative influence of core size, surface chemistry, and charge on nanomaterial toxicity, we tested the biological response of whole animals exposed to a matrix of nine structurally diverse, precision-engineered gold nanoparticles (AuNPs) of high purity and known composition. Members of the matrix include three core sizes and four unique surface coatings that include positively and negatively charged headgroups. Mortality, malformations, uptake, and elimination of AuNPs were all dependent on these parameters, showing the need for tightly controlled experimental design and nanomaterial characterization. Results presented herein illustrate the value of an integrated approach to identify design rules that minimize potential hazard. © 2011 American Chemical Society.


Glover R.D.,University of Oregon | Miller J.M.,Dune Sciences Inc. | Hutchison J.E.,University of Oregon | Hutchison J.E.,Dune Sciences Inc.
ACS Nano | Year: 2011

The use of silver nanoparticles (AgNPs) in antimicrobial applications, including a wide range of consumer goods and apparel, has attracted attention because of the unknown health and environmental risks associated with these emerging materials. Of particular concern is whether there are new risks that are a direct consequence of their nanoscale size. Identifying those risks associated with nanoscale structure has been difficult due to the fundamental challenge of detecting and monitoring nanoparticles in products or the environment. Here, we introduce a new strategy to directly monitor nanoparticles and their transformations under a variety of environmental conditions. These studies reveal unprecedented dynamic behavior of AgNPs on surfaces. Most notably, under ambient conditions at relative humidities greater than 50%, new silver nanoparticles form in the vicinity of the parent particles. This humidity-dependent formation of new particles was broadly observed for a variety of AgNPs and substrate surface coatings. We hypothesize that nanoparticle production occurs through a process involving three stages: (i) oxidation and dissolution of silver from the surface of the particle, (ii) diffusion of silver ion across the surface in an adsorbed water layer, and (iii) formation of new, smaller particles by chemical and/or photoreduction. Guided by these findings, we investigated non-nanoscale sources of silver such as wire, jewelry, and eating utensils that are placed in contact with surfaces and found that they also formed new nanoparticles. Copper objects display similar reactivity, suggesting that this phenomenon may be more general. These findings challenge conventional thinking about nanoparticle reactivity and imply that the production of new nanoparticles is an intrinsic property of the material that is not strongly size dependent. The discovery that AgNPs and CuNPs are generated spontaneously from manmade objects implies that humans have long been in direct contact with these nanomaterials and that macroscale objects represent a potential source of incidental nanoparticles in the environment. © 2011 American Chemical Society.


Reed R.B.,Arizona State University | Reed R.B.,Colorado School of Mines | Zaikova T.,University of Oregon | Barber A.,Colorado School of Mines | And 12 more authors.
Environmental Science and Technology | Year: 2016

For textiles containing nanosilver, we assessed benefit (antimicrobial efficacy) in parallel with potential to release nanosilver (impact) during multiple life cycle stages. The silver loading and method of silver attachment to the textile highly influenced the silver release during washing. Multiple sequential simulated household washing experiments for fabric swatches in deionized water with or without detergent showed a range of silver release. The toxicity of washing experiment supernatants to zebrafish (Danio rerio) embryos was negligible, with the exception of the very highest Ag releases (∼1 mg/L Ag). In fact, toxicity tests indicated that residual detergent exhibited greater adverse response than the released silver. Although washing the fabrics did release silver, it did not affect their antimicrobial efficacy, as demonstrated by >99.9% inhibition of E. coli growth on the textiles, even for textiles that retained as little as 2 μg/g Ag after washing. This suggests that very little nanosilver is required to control bacterial growth in textiles. Visible light irradiation of the fabrics reduced the extent of Ag release for textiles during subsequent washings. End-of-life experiments using simulated landfill conditions showed that silver remaining on the textile is likely to continue leaching from textiles after disposal in a landfill. (Figure Presented). © 2016 American Chemical Society.


Hicks A.L.,University of Wisconsin - Madison | Hicks A.L.,University of Illinois at Chicago | Reed R.B.,Arizona State University | Reed R.B.,Colorado School of Mines | And 8 more authors.
Environmental Science: Nano | Year: 2016

Nanoscale silver has been incorporated into a variety of products where its antimicrobial properties enhance their functionality. One particular application is hospital linens, potential vectors of disease transmission. There is an on-going debate as to whether it is more beneficial to use disposable versus reusable hospital gowns in efforts to prevent nosocomial infections. This work models the life cycle impacts of nanoscale silver (nAg)-enabled, reusable hospital gowns from a life cycle assessment perspective and then compares the midpoint environmental impact data to the use of disposable hospital gowns. A key finding of this work is the environmental parity (when the environmental impact of nAg and disposable gowns are equal) of a nAg-enabled gown is 12 wearings. These results suggest that nAg textiles may be key in reducing the environmental impact of hospitals, while still preventing infection. © 2016 The Royal Society of Chemistry.


Miller J.M.,University of Oregon | Miller J.M.,Dune Sciences Inc. | Glover R.,University of Oregon | Hutchison J.,University of Oregon
Proceedings of the IEEE Conference on Nanotechnology | Year: 2011

Characterization and measurement science lies at the core of fundamental and applied research, technology development, and commercialization in every scientific discipline. Unfortunately, the importance of the characterization process and its burden on time and money resources is often overlooked and becomes a bottleneck to technology development and commercialization[1]. The ad hoc approach to characterization that is widely used today in nanomaterial/technology research and commercialization leads to poor decision making that slows progress. This paper presents a new integrative approach for characterization in all stages of nanomaterials/nanotechnology development that incorporates 1) improved and simplified sample preparation that results in reproducible and accurate data, 2) the ability to perform multitechnique high-resolution nanoscale characterization on the same sample for direct correlation of results, and 3) the ability to probe the behavior of materials under a wide range of different environmental/processing conditions to allow for real-time or sequential ex-situ characterization of the behavior of these materials. Combined, this strategy reduces uncertainty and redundancy, provides new insights to materials behavior, embeds a consistent platform for characterization that can be applied from idea inception to commercialized product, and ultimately saves time and money. We provide a practical application of this strategy to understand the behavior of nanosilver embedded on surfaces and the implications of understanding the fate and reactivity of these materials under conditions that mimic their real-world environments. The strategy employed in this work can be applied by manufacturers, technology developers, and regulatory agencies for a broad range of materials and applications to help guide informed policy decisions, ensure safe products, and reduce the time to market. © 2011 IEEE.


Miller J.M.,Dune Sciences Inc.
MRS Bulletin | Year: 2011

Dune Sciences patent-pending SMART grids™ functionalized characterization substrates imparts greater control over specimen dispersion, coverage, uniformity, and repeatability. SMART grids facilitate correlated analysis using multiple analytical instruments on the same sample to streamline the characterization process. These have thermal, chemical, and physical stability that accommodate a wide range of sample preparation and post-deposition processing conditions. The most recent addition to the SMART grids product line are CSMART functionalized carbon grids that are tuned for low-contrast materials such as biological molecules and applications including cryoelectron microscopy and tomography. SMART grids are available with various surface chemistries and as sample preparation kits for a wide range of materials and application needs.


Patent
Dune Sciences Inc. | Date: 2015-09-14

Embodiments provide electron-conducting, electron-transparent substrates that are chemically derivatized (e.g., functionalized) to enhance and facilitate the deposition of nanoscale materials thereupon, including both hard and soft nanoscale materials. In various embodiments, the substrates may include an electron-conducting mesh support, for example, a carbon, copper, nickel, molybdenum, beryllium, gold, silicon, GaAs, or oxide (e.g., SiO_(2), TiO_(2), ITO, or Al_(2)O_(3)) support, or a combination thereof, having one or more apertures. In various embodiments, the mesh support may be coated with an electron conducting, electron transparent carbon film membrane that has been chemically derivatized to promote adhesion and/or affinity for various materials, including hard inorganic materials and soft materials, such as polymers and biological molecules.


Patent
Dune Sciences Inc. | Date: 2012-01-06

Embodiments provide electron-conducting, electron-transparent substrates that are chemically derivatized (e.g., functionalized) to enhance and facilitate the deposition of nanoscale materials thereupon, including both hard and soft nanoscale materials. In various embodiments, the substrates may include an electron-conducting mesh support, for example, a carbon, copper, nickel, molybdenum, beryllium, gold, silicon, GaAs, or oxide (e.g., SiO_(2), TiO_(2), ITO, or Al_(2)O_(3)) support, or a combination thereof, having one or more apertures. In various embodiments, the mesh support may be coated with an electron conducting, electron transparent carbon film membrane that has been chemically derivatized to promote adhesion and/or affinity for various materials, including hard inorganic materials and soft materials, such as polymers and biological molecules.

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