Nanoparticles in explosives detection – the state-of-the-art and future directions

Nanoparticle-ligand systems can be targeted to specific analytes to effect a change in the properties of the nanoparticles. We will examine two examples in which the electromagnetic properties of the nanoparticles (arising from their small size) are altered by analyte binding, and can be applied as a transducer in a chemical sensing system for explosive analytes. The first property reviewed is the surface plasmon resonance (SPR) band of colloidal gold nanoparticles (AuNPs), and the second, the fluorescence of colloidal semiconductors (quantum dots – QDs). Sensors based on these nanoparticle properties have the potential to detect picomolar or lower concentrations of explosive analytes, and can operate for both solution phase and gas phase detection [1–3]. In addition, measurement of the signal produced by the nanoparticle transducer uses standard scientific instrumentation, making it easier to build complete detection systems from standard components an important consideration [4].