Gold nanoclusters-engineered dual-emitting nanofibrous film for fluorescent discrimination and visual sensing of explosives

Development of reliable sensors for explosive detection is important to reduce explosion-related safety risks and mitigate widespread environmental concerns. However, it remains highly challenging to achieve on-site detection of multiple analytes in a simple yet efficient way. Herein, a flexible electrospun film-based sensing platform by engineering with dual-emitting gold nanoclusters (AuNCs) has been fabricated for the simultaneous fluorescent detection of two representative explosives, hexanitrohexaazaisowurtzitane (CL-20) and trinitrotoluene (TNT). Particularly, two types of AuNCs with different emission colors (green and red) and surface chemistry are designed, which can specifically respond to trace amounts of two explosives separately. While the presence of CL-20 can remarkably enhance the green emission of L-arginine/6-aza-2-thiothymine-protected AuNCs, the presence of TNT can efficiently quench the red emission of glutathione-protected AuNCs. Consequently, ratiometric fluorescent sensing of CL-20 and TNT can be achieved with these dual-emitting AuNCs (G/R-AuNCs), which exhibits a detection limit down to 0.55 and 2.38 µM, respectively. The distinct “turn on” and “turn off” response patterns of G/R-AuNCs towards two explosives could be harnessed to construct fluorescent “BUF” and “NOT” logic gates. Moreover, the present AuNCs-based explosive sensors were deposited into flexible electrospun nanofibrous film for visual and quantitative detection of CL-20 and TNT, which exhibit good mechanical property and promising sensing performance. This work provides a new approach to design explosive sensing platform by coupling the attractive features of fluorescent AuNCs to the electrospun nanofibrous film, which holds great potential for further practical applications.