Combinatorial Pattern Response of Bioelectronic Nose for the Detection of Real Nerve Agents

Abstract

Nerve agents are toxic organophosphorus chemicals and acetylcholinesterase inhibitors that have been used in terrorist acts. Because they exhibit fatal toxic effects in small amounts, technology is required to detect and identify them early. Research for nerve agent detection using structural simulants of real agents may not function properly for real agents depending on the selectivity of the sensor. For practical sensor applications, experiments were conducted using two toxic nerve agents, sarin and VX, which are used in terrorism and attacks. Herein, human olfactory receptors (ORs) were used as sensing materials with high selectivity and sensitivity to target substances. Through molecular dynamic simulations, the interaction results between ORs and target materials were compared, and an OR combination that could distinguish structurally similar target materials was selected. Four types of OR were combined with a graphene/MoS₂-based n-type field-effect transistor platform to create a bioelectronic nose that showed remarkable sensitivity and a stable basal current to convert the biological signals of the OR with target substances into electrical signals. This study developed a nerve agent detection technology using multiple OR sensing signals, advocating combinatorial pattern recognition, which is the core of the human olfactory mechanism. The bioelectronic nose effectively distinguishes structurally similar nerve agents using pattern signals.