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

## TL;DR

This paper introduces a biohybrid sensor using locust antennae to detect solid explosives like TNT and RDX without heating or chemicals.

## Contribution

A novel biohybrid sensor with active sniffing and machine learning for detecting low-volatility explosives in solid form.

## Key findings

- The system detects explosives like TNT and RDX with a threshold as low as 2.67 pg.
- It discriminates explosives from nonexplosive solids without chemical preprocessing.
- The sensor matches or outperforms existing detection methods in sensitivity.

## Abstract

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.