Fluorescence-based trace detection of explosives: current state and perspective for ultrasensitive portable technique...

Considering the recent global growth of terrorism and widespread environmental contamination caused by the previous military actions and ongoing wars, it is evident that the importance of innovation in trace detection of explosives has increased significantly. Specifically, it is vital to develop sensitive, fast, cheap, portable and mass-producible sensors, which will overcome the drawbacks of conventional techniques used for detecting the most widespread explosives, especially those based on nitro compounds. Recently, various optical sensors have been proposed for the detection of explosives due to their real-time, highly sensitive response with significant miniaturization potential. Among them, fluorescence-based sensors have emerged as a promising technique, which can be further improved by employing the plasmon-enhanced fluorescence (PEF) phenomenon for achieving lower detection limits, thus providing the ability to detect different analytes at ultra-low concentrations in a portable format. This paper provides a comprehensive overview of the current state of fluorescence-based trace detection of explosives, highlighting key mechanisms, recent developments and innovations. The prospects of PEF for developing an ultrasensitive portable technique via enhancement provided by plasmonic nanostructures are also discussed, which is important for pursuing innovations in environmental remediation and humanitarian demining.