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Metropolitan Government of Nashville-Davidson (balance), TN, United States

Gaur G.,Vanderbilt University | Koktysh D.S.,Vanderbilt Institute of Nanoscale Science and Engineering | Weiss S.M.,Vanderbilt University
Advanced Functional Materials | Year: 2013

Highly sensitive dual-mode labeled detection of biotin in well-characterized porous silicon (PSi) films using colloidal quantum dots (QDs) as signal amplifiers are demonstrated. Optimization of the PSi platform for targeted QD infiltration and immobilization is carried out by characterizing and tuning the porosity, film depth, and pore size. Binding events of target QD-biotin conjugates with streptavidin probes immobilized on the pore walls are monitored by reflective interferometric spectroscopy and fluorescence measurements. QD labeling of the target biotin molecules enables detection based on a distinct fluorescent signal as well as a greater than 5-fold enhancement in the measured spectral reflectance fringe shift and a nearly three order of magnitude improvement in the detection limit for only 6% surface area coverage of QDs inside the porous matrix. Utilizing the QD signal amplifiers, an exceptional biotin detection limit of ≈6 fg mm-2 is demonstrated with sub-fg mm-2 detection limits achievable. White light reflective interferometric spectroscopy and fluorescence measurements are used to implement a novel dual-mode optical porous silicon biosensor. Quantum dots act as signal amplifiers resulting in over an order of magnitude increase in sensor response and providing a secondary means of biomolecule-specific recognition through their distinct fluorescence spectra. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


McClure R.,Vanderbilt University | Yanagisawa D.,Shiga University of Medical Science | Stec D.,Vanderbilt University | Abdollahian D.,Vanderbilt University | And 10 more authors.
Journal of Alzheimer's Disease | Year: 2015

Curcumin is a promising compound that can be used as a theranostic agent to aid research in Alzheimer's disease. Beyond its ability to bind to amyloid plaques, the compound can also cross the blood-brain barrier. Presently, curcumin can be applied only to animal models, as the formulation needed for iv injection renders it unfit for human use. Here, we describe a novel technique to aerosolize a curcumin derivative, FMeC1, and facilitate its safe delivery to the brain. Aside from the translational applicability of this approach, a study in the 5XFAD mouse model suggested that inhalation exposure to an aerosolized FMeC1 modestly improved the distribution of the compound in the brain. Additionally, immunohistochemistry data confirms that following aerosol delivery, FMeC1 binds amyloid plaques expressed in the hippocampal areas and cortex. © 2015 - IOS Press and the authors. All rights reserved. Source


Douglas A.,Vanderbilt University | Muralidharan N.,Vanderbilt University | Carter R.,Vanderbilt University | Share K.,Vanderbilt University | And 2 more authors.
Nanoscale | Year: 2016

Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. © 2016 The Royal Society of Chemistry. Source


Kobukai S.,Vanderbilt University | Baheza R.,Vanderbilt University | Cobb J.G.,Vanderbilt University | Virostko J.,Vanderbilt University | And 7 more authors.
Magnetic Resonance in Medicine | Year: 2010

We report the development of superparamagnetic iron oxide (SPIOs) nanoparticles and investigate the migration of SPIOlabeled dendritic cells (DCs) in a syngeneic mouse model using magnetic resonance (MR) imaging. The size of the dextran- coated SPIO is roughly 30 nm, and the DCs are capable of independent uptake of these particles, although not at levels comparable to particle uptake in the presence of a transfecting reagent. On average, with the assistance of polylysine, the particles were efficiently delivered inside DCs within one hour of incubation. The SPIO particles occupy approximately 0.35% of cell surface and are equivalent to 34.6 pg of iron per cell. In vivo imaging demonstrated that the labeled cells migrated from the injection site in the footpad to the corresponding popliteal lymph node. The homing of labeled cells in the lymph nodes resulted in a signal drop of up to 79%. Furthermore, labeling DCs with SPIO particles did not compromise cell function, we demonstrated that SPIO-enhanced MR imaging can be used to track the migration of DCs effectively in vivo. © 2010 Wiley-Liss, Inc. Source


Douglas A.,Vanderbilt University | Carter R.,Vanderbilt University | Oakes L.,Vanderbilt University | Share K.,Vanderbilt University | And 3 more authors.
ACS Nano | Year: 2015

Nanocrystals with quantum-confined length scales are often considered impractical for metal-ion battery electrodes due to the dominance of solid-electrolyte interphase (SEI) layer effects on the measured storage properties. Here we demonstrate that ultrafine sizes (μ4.5 nm, average) of iron pyrite, or FeS2, nanoparticles are advantageous to sustain reversible conversion reactions in sodium ion and lithium ion batteries. This is attributed to a nanoparticle size comparable to or smaller than the diffusion length of Fe during cation exchange, yielding thermodynamically reversible nanodomains of converted Fe metal and NaxS or LixS conversion products. This is compared to bulk-like electrode materials, where kinetic and thermodynamic limitations of surface-nucleated conversion products inhibit successive conversion cycles. Reversible capacities over 500 and 600 mAh/g for sodium and lithium storage are observed for ultrafine nanoparticles, with improved cycling and rate capability. Unlike alloying or intercalation processes, where SEI effects limit the performance of ultrafine nanoparticles, our work highlights the benefit of quantum dot length-scale nanocrystal electrodes for nanoscale metal sulfide compounds that store energy through chemical conversion reactions. © 2015 American Chemical Society. Source

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