Detection of Solid-Phase Explosives Using an Electroantennogram-Based Biohybrid Sensor with Active Sniffing

Effective detection of hazardous compounds such as explosives is a critical objective in the fields of security and environmental monitoring. However, these materials, especially in their solid phase, present considerable analytical challenges due to their low vapor pressure and limited volatility under ambient conditions. In this study, we present a biohybrid sensing system that integrates an electroantennogram (EAG) recording from the antenna of the desert locust (Schistocerca gregaria), a bioinspired active sniffing mechanism, and machine learning assisted classification. This system enables noncontact detection of low-volatility compounds, without the need for heating, solvent extraction, or chemical preprocessing. It can reliably detect explosives such as trinitrotoluene (TNT), hexogen (RDX), and gunpowder and can discriminate TNT and RDX from nonexplosive solid odorants. A detection threshold of 2.67 pg was achieved for solid-phase TNT, which matches or even goes below previously reported detection approaches. These findings highlight the potential of insect-based biohybrid sensors as practical, low-cost tools for real-world chemical sensing, with promising applications in hazardous material monitoring.