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. Source
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. Source
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.
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.
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.