Physics Colloquium - Spring 2006 - Uses of Nanoparticles in Chemical and Biological Sensors
Dept of Physics & Astronomy
University of Maine, Orono, Maine
Presents
Dr. C.V. Gopal Reddy
Research Associate
Dept. of Chemical & Biological Engineering
UMaine
Uses of Nanoparticles in Chemical and Biological Sensors
Sensors have become integrated into our daily lives, for either chemical, biological, mechanical, or optical applications. Nanoparticles offer tremendous potential in the areas of nanoelectronics, bio- and chemo sensors, and catalysis. However, before these applications are realized, the surface functionality of nanoparticles must be better controlled. The purpose of our current research is to build up the multidisciplinary research effort devoted to the development of functionalized nanoparticles for advanced imaging techniques in novel sensor applications. Different size, shapes of gold, silver nanoparticles have been synthesized using documented methods involving the reduction of gold, silver solution by reducing agent with and without a stabilizing agent in aqueous and organic medium. Characterization of these materials based on size has been determined using TEM, AFM, Zetasizer and UV-Visible spectroscopy. Modification of these inorganic materials with organic molecules to functionalize systems with molecular/biomolecular recognition elements such as thiols, 1,2-bis(4-pyridyl)ethylene (BPE), and pyridine etc. has been explained with surface enhanced Raman scattering (SERS) technique. SERS allows for in situ real time measurements, non-destructive and non-intrusive sampling, remote sampling through fiber optics, and detection of analytes in aqueous solvents by adsorbing the analyte onto nanostructured gold and silver surfaces. This can lead to Raman spectra that are a million times more intense than ones without surface enhancement.
Gold nanoparticles also used for thin films of membranes for separation of gas molecules from organic mixtures. Multiple Longmuir-Blodgett depositions of 15 nm gold nanoparticles onto a mesoporous silica membrane resulted in a membrane with a significantly modified gas permeance and a decreased number of active pores of radii 40 Å and less.
Friday, March 31, 2006
3:10 pm
140 Bennett Hall
Refreshments will follow in Rm. 114, Bennett Hall
Reddy Biography
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