Advances in detection of hazardous organophosphorus compounds using organophosphorus hydrolase based biosensors

Agricultural advancements focusing on increasing crop production have led to excessive usage of insecticides and pesticides, resulting in leaching and accumulation of these highly toxic chemicals in soil, water, and the food-chain. Organophosphorus (OP) compounds are the most commonly used insecticides and pesticides, which cause a wide range of long-lasting and life-threatening conditions. Due to the acute toxicity and long-term side effects of OP compounds, their timely, on-the-spot and rapid detection has gained importance, for efficient healthcare management. In this respect, several OP degrading enzymes have gained the spotlight in developing the enzyme-based biosensors, owing to their high activity and broad specificity. Among these enzymes, organophosphorus hydrolase (OPH) has emerged as a promising candidate for the detection of OP compounds, due to its ability to act on a broad range of substrates having a variety of bonds, like P─F, P─O, P─S, and P─CN. Various techniques employing OPH in free/immobilized/conjugated forms into sensing devices were reported to accurately detect OP compounds. The transduction mechanisms of bio-sensing are electrochemical, optical as well as novel methods like magnetoelastic/surface plasmon resonance. Furthermore, to improve the detection limits and sensitivity, nanoparticles and quantum dots are often employed in conjunction with OPH. Here, we highlight the recent advances in sensing OP compounds using OPH based biosensors, compare specifications of sensing methods, and evaluate the influence of different materials used in developing sensors. This review will also enable researchers to design and configure highly sensitive and accurate sensing systems, leading to the development of point-of-care devices for real-time analysis.