Reduced Graphene Oxide Modified Enzyme Inhibition-Based Biosensor System for Detection of Paraoxon as a Nerve Agent Simulant

Abstract

Nerve agents, including organophosphorus compounds such as paraoxon, are potent and highly toxic chemicals with grave implications for human health and the environment. In this paper, we present the development of a novel enzyme inhibition-based biosensor for the sensitive and selective detection of paraoxon, which is commonly used as a surrogate for nerve agents. The biosensor employs reduced graphene oxide as a screen-printed electrode surface modification nanomaterial, leading to increased surface electroactivity and, thus, more sensitive detection. The biosensor exhibits a low detection limit of 0.56 pg/ml (limit of detection, LOD) and 1.25 pg/ml (limit of quantification, LOQ), highlighting its high sensitivity for trace-level analysis of nerve agents in complex sample matrices. Our biosensor demonstrates remarkable selectivity for paraoxon, with minimal interference from other non-target chemicals. Stability and repeatability tests reveal that the system maintains its performance integrity over a 45-day period and consistently produces readings with a margin of error of only 5%. Real sample testing in river water, wastewater, and tap water further confirms the biosensor's practical utility, with recovery percentages ranging from 84 to 115%. This biosensor represents a significant advancement in biosensor technology, facilitating the rapid, cost-effective, and reliable detection of toxic substances in real-world scenarios.