A Review on Recognition of Explosives using Calixarene Framework

In terms of social security and support, quick, ultra-sensitive, and ultra-selective detection of explosives is urgently needed around the world. This review is ardent to calixarene a recent selective and sensitive explosive sensor. The structural binding properties of the Calix system and macromolecules can be modified by various structural mode changes and interactions, and multiple possibilities of functionalization of the calixarene make these versatile molecules in the phenomena of specific recognition. This study reflects on the use of fluorescence-based chemosensors for explosive detection that has been mentioned in the literature. From this review, it is implied that calixarene excellently complexes with high selectivity explosives and attraction associated with other simple ion receptor applications using different ions.

Colorimetric optical nanosensors for trace explosive detection using metal nanoparticles: advances, pitfalls, and future perspective

Warfare threats and acts of terror are challenging situations encountered by defense agencies across the globe and are of growing concern to the general public, and security-minded policy makers. Detecting ultra-low quantities of explosive compounds in remote locations or under harsh conditions for anti-terror purposes as well as the environmental monitoring of residual or discarded explosives in soil, remains a major challenge. The use of metal nanoparticles (NPs) for trace explosive detection has drawn considerable interest in recent years. For nano-based explosive sensor devices to meet real-life operational demands, analytical parameters such as, long-shelf life, stability under harsh conditions, ease-of-use, high sensitivity, excellent selectivity, and rapid signal response must be met. Generally, the analytical performance of colorimetric-based nanosensor systems is strongly dependent on the surface properties of the nanomaterial used in the colorimetric assay. The size and shape properties of metal NPs, surface functionalisation efficiency, and assay fabrication methods, are factors that influence the efficacy of colorimetric explosive nanosensor systems. This review reports on the design and analytical performances of colorimetric explosive sensor systems using metal NPs as optical signal transducers. The challenges of trace explosive detection, advances in metal NP colorimetric explosive design, limitations of each methods, and possible strategies to mitigate the problems are discussed.