Dobrokhotov V.,Western Kentucky University |
Oakes L.,Western Kentucky University |
Sowell D.,Western Kentucky University |
Larin A.,Western Kentucky University |
And 8 more authors.
Sensors and Actuators, B: Chemical | Year: 2012
Chemical sensors were fabricated on the basis of novel nanomaterials - silica nanosprings. High chemical sensitivity was achieved by coating the silica nanosprings with ZnO using atomic layer deposition (ALD), followed by decorating with metal nanoparticles. The optimum operational conditions (T = 400°C, ZnO grain size ∼15 nm) were obtained and investigated. The nanospring-based sensors demonstrated remarkable vapor sensing properties: well-defined spikes in conductance upon exposure to explosives (TNT, TATP) and flammable vapors (toluene, acetone, ethanol) were obtained for 0.1 ms exposure times at ppb level. Based on surface doping of ZnO with various metallic nanoparticles, a discrimination mechanism was developed and an integrated sensor-array for simultaneous real-time resistance scans was built. The integrated sensor response was tested using linear discriminant analysis (LDA). The distinguished electronic signatures of various chemical vapors were obtained at ppm level. © 2012 Elsevier B.V.
Timalsina Y.P.,University of Idaho |
Branen J.,University of Idaho |
Aston D.E.,University of Idaho |
Noren K.,University of Idaho |
And 4 more authors.
Journal of Applied Physics | Year: 2011
In this study, alternating current impedance spectroscopic analysis of the biofunctionalization process of a vertically-aligned (silica) nanosprings (VANS) surface is presented. The VANS surface is functionalized with a biotinylated immunoglobulin G (B-IgG) layer formed by physisorption of B-IgG from the solution phase. Bovine serum albumin passivation of the B-IgG layer reduces additional surface adsorption by blocking the potential sites of weak bond formation via electrostatic and hydrophobic interactions. As avidin acts as a receptor of biotinylated compounds, avidin conjugated glucose oxidase (Av-GOx) binds to the B-IgG layer via biotin. This avidin-biotin bond is a stable bond with high association affinity (Ka=1015 M-1) that withstands wide variations in chemistry and pH. An IgG layer without biotin shows no binding to the Av-GOx, indicating that bonding is through the avidin-biotin interaction. Finally, fluoroscein iso-thiocyanate (FITC) labeled biotinylated bovine serum albumin (B-BSA) added to the Av-GOx surface is used to fluorescently label Av-GOx for fluorescent measurements that allow for the correlation of surface binding with impedance measurements. Modeling of impedance spectra measured after the addition of each biological solution indicates that the bimolecular layers behave as insulating layers. The impedance spectra for the VANS-based sensor are compared to simple parallel capacitor sensors, sans VANS, and serve as controls. VANS-based sensors exhibit a greater magnitude of change between successive bio-layers relative to the controls below 10 kHz. Changes in the magnitudes of the components of the VANS equivalent circuit indicate that the addition of biological layers changes the effective dielectric response of the VANS via the impediment of ionic motion and biomolecule polarization. © 2011 American Institute of Physics.
Sai V.V.R.,University of Idaho |
Gangadean D.,University of Idaho |
Gangadean D.,Maricopa Community Colleges |
Niraula I.,University of Idaho |
And 8 more authors.
Journal of Physical Chemistry C | Year: 2011
Silica nanosprings with large surface-to-volume ratios were coated with noble metal nanoparticles (NPs) using chemical vapor deposition or chemisorption of presynthesized or in situ synthesized nanoparticles. Chemisorption of presynthesized silver NPs onto amine-functionalized silica NS results in particularly interesting materials with small interparticle spacings and high surface-enhanced Raman scattering activity. SERS enhancement factors approaching ∼1010 were observed with thiophenol. In an alternative approach, silica NS coated with core-shell nanostructures, formed by deposition of catalytically reduced silver on AuNP-coated NS, exhibit a highly uniform SERS response with enhancement factors of ∼108. The advantages of these materials include (i) commercial availability of silica nanosprings, AuNPs/AgNPs, and silver enhancer solutions, (ii) simplicity and reproducibility of functionalization and deposition steps, and (iii) high SERS activity of these substrates rendering them of considerable interest for a variety of sensor applications. © 2010 American Chemical Society.
Schilke K.F.,Oregon State University |
Wilson K.L.,Oregon State University |
Cantrell T.,GoNano Technologies |
Corti G.,GoNano Technologies |
And 4 more authors.
Biotechnology Progress | Year: 2010
The use of silicon dioxide (SiO 2) nanosprings as supports for immobilized enzymes in a continuous microreactor is described. A nanospring mat (2.2 cm 2 × 60 μm thick) was functionalized with γ-aminopropyltriethoxysilane, then treated with N-succinimidyl-3-(2-pyridyldithio)-propionate (SPDP) and dithiothreitol (DTT) to produce surface thiol (-SH) groups. SPDP-modified β-galactosidase from Aspergillus oryzae was immobilized on the thiolated nanosprings by reversible disulfide linkages. The enzyme-coated nanospring mat was placed into a 175-μm high microchannel, with the mat partially occluding the channel. The kinetics and steady-state conversion of hydrolysis of o-nitrophenyl β-D-galactosylpyranoside at various substrate flow rates and concentrations were measured. Substantial flow was observed through the nanosprings, for which the Darcy permeability κ ≈ 3 × 10 -6 cm 2. A simple, one-parameter numerical model coupling Navier-Stokes and Darcy flow with a pseudo-first-order reaction was used to fit the experimental data. Simulated reactor performance was sensitive to changes in κ and the height of the nanospring mat. Permeabilities lower than 10 -8 cm 2 practically eliminated convective flow through the nanosprings, and substantially decreased conversion. Increasing the height of the mat increased conversion in simulations, but requires more enzymes and could cause sealing issues if grown above channel walls. Preliminary results indicate that in situ regeneration by reduction with DTT and incubation with SPDP-modified β-galactosidase is possible. Nanosprings provide high solvent-accessible surface area with good permeability and mechanical stability, can be patterned into existing microdevices, and are amenable to immobilization of biomolecules. Nanosprings offer a novel and useful support for enzymatic microreactors, biosensors, and lab-on-chip devices. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 © 2010 American Institute of Chemical Engineers (AIChE).
GoNano Technologies | Date: 2012-10-05
Catalytic converters and insert materials for catalytic converters comprising metalized nanostructures coated on metal or ceramic honeycomb substrates are described. The nanostructures can be bonded directly to the channel walls of the metal or ceramic honeycomb substrates, and generally extend approximately 0.1 mm into the open pore volume of the substrates. The nanostructured coating can be used to support various catalyst formulations, where the nanostructured coating can provide advantages such as increasing reactivity of the catalysts by providing higher accessible surface area, decreasing light-off temperature through enabling smaller particle size of the catalysts, improving durability and lifetime of the catalysts through increased thermal stability, decreasing costs through reduced amounts of precious metals, and/or functioning as a filter for particulate matter.
GoNano Technologies | Date: 2011-07-07
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 178.17K | Year: 2011
This Small Business Innovation Research (SBIR) Phase I project will demonstrate the technical and commercial viability of a novel four-way catalytic converter for lean burn diesel applications that is based on high-surface area nanomaterials applied directly to the inner walls of existing catalytic converter monoliths. While there is ongoing research to integrate diesel particulate filters and the oxidation catalyst, there is little research addressing the integration of all four components (oxidation of carbon monoxide, oxidation of hydrocarbons, capture and destruction of carbon particulate matter (PM) and reduction of NOx.
The broader/commercial impacts of this research are that in 2013 strict requirements for diesel emissions standards will become law. These new regulations will effect carbon emissions both in terms of particle size and number of particles. While there are proposals to meet impending PM regulations, none actively integrate all the required functions of a catalytic converter. Therefore the potential U.S. commercial value of the catalytic converter structure from this project is significant. The European market opportunity may be larger since diesel engines are more prevalent in Europe.
Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 148.72K | Year: 2011
This Small Business Innovation Research (SBIR) Phase I project will demonstrate the technical and commercial viability of a novel four-way catalytic converter for lean burn diesel applications that is based on high-surface area nanomaterials applied directly to the inner walls of existing catalytic converter monoliths. While there is ongoing research to integrate diesel particulate filters and the oxidation catalyst, there is little research addressing the integration of all four components (oxidation of carbon monoxide, oxidation of hydrocarbons, capture and destruction of carbon particulate matter (PM) and reduction of NOx. The broader/commercial impacts of this research are that in 2013 strict requirements for diesel emissions standards will become law. These new regulations will effect carbon emissions both in terms of particle size and number of particles. While there are proposals to meet impending PM regulations, none actively integrate all the required functions of a catalytic converter. Therefore the potential U.S. commercial value of the catalytic converter structure from this project is significant. The European market opportunity may be larger since diesel engines are more prevalent in Europe.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 176.38K | Year: 2010
This SBIR Phase I project will convert (recycle) CO2 into useful and economically important by-products (i.e., industrial feed stocks) using a nano crystalline anatase (TiO2) photo catalyst with a high surface area. Anatase is a well known photo-catalyst. The co-founders of the Nanospring platform hold a patent on the project catalyst system that has shown the ability to convert CO2 to methanol (using a gas-to-gas continuous reactor, patent applied for), and, possibly, formic acid and formaldehyde at room temperature. Specifically, the research will develop and test a filter-type system that could be retrofitted in-line of the exhaust stacks at power and industrial plants. This approach is termed Carbon Capture and Recycle. The Research Plan addresses three objectives by three sets of tests at the laboratory scale: 1) evaluation of the catalytic properties of the TiO2-coated silica Nanosprings mat formed on a 100 um glass frit; 2) optimization of the catalyst coating; and 3) evaluation and testing of the prototype catalyst filter system using real world flue gas emissions.
The broader/commercial impact of the proposed project will be the potential for successful commercial application. There is a need for technologies that will reduce the carbon emitted to the atmosphere from coal-fired plants, and the project includes support from a large power company. The technology is particularly competitive for power plants that are long distances from geologically suitable CO2 storage sites. The process not only will be continuous flow but also could be by-product tuneable, i.e., generating a variety of chemicals by controlling operating conditions. Based on the 30% efficiency identified in the preliminary laboratory testing, the process could convert one metric ton of CO2 into 0.245 metric tons of methanol.
Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 147.55K | Year: 2009
This Small Business Innovation Research Phase I project is for development of Nanospring mats for electrodes in next generation ultracapacitors. The mats have high surface area for integration into ultracapacitor devices. The high specific power of ultracapacitors coupled with their ability to be rapidly charged and the potential for lightweight structures make these devices of significant interest for automotive applications in hybrid and fully electric vehicles.