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Ithaca, NY, United States

Schmit V.L.,University of Wyoming | Martoglio R.,DePauw University | Scott B.,University of Wyoming | Strickland A.D.,Ifyber, Llc | Carron K.T.,University of Wyoming
Journal of the American Chemical Society | Year: 2012

This paper describes the development and preparation of a new class of materials for surface-enhanced Raman scattering (SERS) consisting of gold nanoparticles coated onto hollow, buoyant silica microspheres. These materials allow for a new type of molecular assay designated as a lab-on-a-bubble (LoB). LoB materials serve as a convenient platform for the detection of analytes in solution and offer several advantages over traditional colloidal gold and planar SERS substrates, such as the ability to localize and concentrate analytes for detection. An example assay is presented using the LoB method and cyanide detection. Cyanide binds to SERS-active, gold-coated LoBs and is detected directly from the corresponding SERS signal. The abilities of LoBs and a gold colloid to detect cyanide are compared, and in both cases, a detection limit of ∼170 ppt was determined. Differences in measurement error using LoBs versus gold colloid are also described, as well as an assay for 5,5″-dithiobis(2- nitrobenzoic acid) that shows the benefit of using LoBs over SERS analyses in colloids, which are often plagued by particle aggregation. © 2011 American Chemical Society.

This paper describes a layer-by-layer (LBL) electrostatic self-assembly process for fabricating highly efficient antimicrobial nanocoatings on a natural cellulose substrate. The composite materials comprise a chemically modified cotton substrate and a layer of sub-5 nm copper-based nanoparticles. The LBL process involves a chemical preconditioning step to impart high negative surface charge on the cotton substrate for chelation controlled binding of cupric ions (Cu 2+), followed by chemical reduction to yield nanostructured coatings on cotton fibers. These model wound dressings exhibit rapid and efficient killing of a multidrug resistant bacterial wound pathogen, A. baumannii, where an 8-log reduction in bacterial growth can be achieved in as little as 10 min of contact. Comparative silver-based nanocoated wound dressings-a more conventional antimicrobial composite material-exhibit much lower antimicrobial efficiencies; a 5-log reduction in A. baumannii growth is possible after 24 h exposure times to silver nanoparticle-coated cotton substrates. The copper nanoparticle-cotton composites described herein also resist leaching of copper species in the presence of buffer, and exhibit an order of magnitude higher killing efficiency using 20 times less total metal when compared to tests using soluble Cu 2+. Together these data suggest that copper-based nanoparticle-coated cotton materials have facile antimicrobial properties in the presence of A. baumannii through a process that may be associated with contact killing, and not simply due to enhanced release of metal ion. The biocompatibility of these copper-cotton composites toward embryonic fibroblast stem cells in vitro suggests their potential as a new paradigm in metal-based wound care and combating pathogenic bacterial infections. Nanostructured copper coatings on natural cellulose (woven cotton substrate; left) are produced using a layer-by-layer electrostatic self-assembly process. The resulting copper nanoparticle-coated cotton fiber composites exhibit extremely efficient antimicrobial activity against a multi-drug resistant bacterial pathogen through a putative contact-killing mechanism at the nanostructured cotton interface. The substrates exhibit an 8-log reduction in bacterial growth in as little as ten minutes. These unique materials also show mammalian cell biocompatibility as indicated in the confocal fluorescence microscopy image showing healthy mouse fibroblast cells growing in the presence of nanostructured copper-coated cotton substrates after 48 hours. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 150.00K | Year: 2013

This Small Business Innovation Research (SBIR) Phase I project aims to develop a topical formulation incorporating a polymeric platform that releases therapeutic levels of nitric oxide gas, and assess its efficacy in dispersing wound-relevant bacterial biofilms. The intellectual merit of the proposed project is built around the remarkable characteristics of the polymeric system, where under appropriate conditions this polymer can provide sustained release of nitric oxide over long periods of time and at low concentrations that are biocompatible. The benefit of this characteristic is substantial. Firstly, it avoids the toxicity problems associated with high levels of reactive species formed in response to concentrated nitric oxide release. Secondly, the low levels of nitric oxide release from the polymer will result in increased bioavailability of nitric oxide for promotion of wound healing. Taken together, the characteristics of the proposed nitric oxide releasing polymer prodrug may offer a significant improvement over current approaches to chronic wound treatment.

The broader impact/commercial potential of this project will be determined by market needs that the technology addresses. Colonization of surfaces by biofilms is a significant problem not only in the clinical field, but also across industry and environmental biotechnology sectors. As such, there is a growing requirement for technologies that can either prevent biofilm growth or disperse an existing biofilm, and that can be manufactured in a cost effective manner. The technology that is put forward for development in this Phase I proposal has characteristics that are in line with these requirements. By demonstrating successful development of a product for treatment of wound-related biofilms, a solid foundation will be put in place for exploring similar biofilm prevention or eradication needs across other market sectors.

Agency: Department of Defense | Branch: Defense Advanced Research Projects Agency | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2011

iFyber LLC proposal define a novel solution for the Point-of-Care diagnostics market. Traditional In-Vitro Diagnostic testing most often requires multiple steps (sample purification and analyte separation, analyte concentration/amplification, and detection) to achieve even qualitative levels of detection. iFyber proposes to develop and commercialize an entirely new paradigm in the POC diagnostic market that utilizes a unique microsphere-based, passive proximity assay (PPA) for integrated sample purification and target analyte capture, concentration and detection

Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2010

This Small Business Innovation Research (SBIR) Phase I project aims to develop a novel textile coating and reading device for positive identification applications such as anti-counterfeit, textile brand verification, etc. The basis of this project is to use a layer-by-layer self-assembly process to control the interface between engineered textile substrates and nanomaterials. The resulting nanostructured composite materials may display a unique property that can be detected by a reading device. This technology allows for the precise control over the deposition of metal nanoparticle materials onto the surface of natural and synthetic textiles, which can be implemented into standard industrial processes. The broader/commercial impacts of this project will be the potential to provide a technology for positive identification and anti-counterfeit of textile products, which ranges from the basic clothing industry to military applications.

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