Portable hydrogel-based tri-channel fluorescence sensor array for visual detection of multiple explosives

The identification and detection of various types of explosives are essential for human health and environmental monitoring. Array-based sensing approach offers significant advantages in detecting multi-analytes simultaneously, thereby holding great potential in identifying multiple explosives. Here, we report a tri-channel fluorescence array composed of three distinct fluorescence probes based on gold nanoclusters and nicotinamide adenine dinucleotide with well-separated emission colors. Through the specific interactions of explosives with different fluorescent probes and the yielded response patterns, seven explosives can be successfully distinguished with 100% accuracy. In particular, the sensor array exhibits excellent performance in the quantitative analysis of individual explosive and the differentiation of multiple explosive mixtures. To facilitate the field detection towards practical application, the tri-channel fluorescence array was further integrated with polymer hydrogels. The fabricated portable hydrogel-based array sensors can not only visually identify seven different explosives by their distinct fluorescence color change, but also enable quantitative detection based on linear discriminant analysis (LDA) together with a smartphone. This study illustrates the great potential of hydrogel-based fluorescence sensor array as robust sensors for explosives, which also holds significant promise for the development of portable explosive devices towards practical application.