Detection of Biological Analytes at Physiological Conditions using Localized Surface Plasmon Resonance Spectroscopy

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This work exploits the use of noble metal nanoparticles to achieve sensitive and selective detection of chemical and biological analytes. The localized surface plasmon resonance (LSPR) of these metal nanoparticles is known to be sensitive to shape, size, and the local environment. Ag nanoparticles fabricated using the nanosphere lithography (NSL) technique exploit this LSPR sensitivity as a signal transduction method in biosensing applications. Current work strives to investigate the impact of changing the nanoparticle aspect ratio on the solvent sensitivity of the assay and to implement LSPR biosensing in a dinitrophenyl (DNP) derivative immunoassay system. Antidinitrophenyl (antiDNP) is an analog of trinitrotoluene (TNT). Thus, the antiDNP binding study will provide enormous insight into the detection of chemical warfare reagents. In studying the impact of particle aspect ratio on sensitivity, it was found that for a 390 nm diameter nanosphere mask, the particles with the shortest height, 15 nm, demonstrated the highest sensitivity, 265.44 nm RIU-1 [(refractive index unit)-1]. Upon formation of the DNP/antiDNP complex in phosphate buffered water, the system showed an average LSPR shift of 15 nm for a particle height of 25 nm. Further nonspecific binding studies showed high analyte specificity in three separate cases: when the DNP derivative was not attached, when bovine serum albumin (BSA) was introduced, and in a mixture of BSA and the DNP derivative.

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  • 07/17/2018
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