Date of Award
Master of Science (MS)
With an increasing use of improvised explosive devices in combat and terrorism, there is an urgent need for novel methods of trace explosive detection that can provide an inexpensive and effective solution. This study focuses on the development of such platform using flexible surface enhanced Raman scattering (SERS) substrates. Gold nanorods(AuNR) functionalized with peptides selective to explosive molecules, trinitrotoluene(TNT) and dinitrotoluene (DNT) were immobilized on various substrates to fabricate a flexible SERS substrate. The peptide conjugated AuNRs can detect TNT and DNT vapors, and the cysteamine conjugated nanorods could detect TNT in aqueous solution down to 100 nM.
Additionally, we also proposed the design of a 3D structures to improve the sensitivity of SERS detection. The synthesis of 3D nanostructures involves the growth of zinc oxide nanowires on paper substrates, followed by the adsorption of gold nanorods on the ZnO nanowires. The resulting structure had a higher surface area and higher number of AuNRs within the laser footprint compared to paper adsorbed with AuNRs enabling and are expected to exhibit higher SERS enhancement. The ZnO-AuNR paper substrate showed higher SERS sensitivity than planar silicon and plasmonic paper surfaces. The unique design of zinc oxide – paper hybrid substrate improved the sensitivity of SERS based detection. The advances in the development of unique SERS substrates and the design of the recognition elements for explosive detection is a critical step towards to the design of SERS based chemical sensors.
Srikanth Singamaneni, Ph.D
Guy Genin, Ph.D Jeremiah Morrissey, Ph.D