Development of nanowell based sensors for the detection of improvised explosive devices

Abstract

World events have called for a need for fast, reliable, and more deployable methods of detection of improvised explosive devices (IEDs) than trained canines and visible detection by X-ray screening technologies. Anodized Aluminum Oxides (AAOs) are ideal substrates for chemical sensor developments. The nanoporous structure provides small pore-to-pore distance and large surface areas. These unique qualities allow optical interference in the visible spectrum when the thin film thickness is in the proper range. By coating the nanowells of the oxide surface first with a thin film of a noble metal followed by a monolayer of a target-specific chemical, detection of trace amounts of explosive materials becomes possible. Research has shown that the carboxyl group of 6-mercaptopyridine-3-carboxylic acid (6-MNA) has an attraction to the nitro groups of 2,4,6-trinitrotoluene (TNT) while the thiol group of 6-MNA creates a self-assembled monolayer on the substrate. By utilizing these chemical properties together, UV-vis spectrometry can detect a shift in the visible spectrum on the coated AAO substrate as the 6-MNA structure attracts trace amounts of TNT particles.