Development of a disposable mimetic biosensor for organophosphorous and carbamate pesticides for the quality control of water supply

Abstract

With the introduction of synthetic pesticides in the early 70´s and with the subsequent awareness of their hazardous effects in the human health, analytical methods, presenting high sensitivity and selectivity as well as suitability for miniaturization aiming "in situ" applications on the field and in real time, have become the main objective of several research groups, around the world. However, portable and accurate devices, as required for such applications are mostly related with biosensors. Among them, the amperometric enzymatic biosensors are most appropriated. But the high cost of the enzyme used for pesticide monitoring (acetylcholinesterase) and its inherent instability have become their application a problematic issue. Moreover, some pesticides yield an irreversible inhibition in the enzymatic activity, making useless the biosensor, after the first measurement. In this way, cheap and disposable devices are of great interest. Previous work in the Grupo de Materiais Eletroquímicos e Métodos Eletroanalíticos from the Instituto de Química de São Carlos, USP, showed that the 4-[(1E)ethanehydrazonoyl]benzoic acid acts as a mimetic for acetilcholinesterase promoting the esterase of its substrate, acetylcholine being by the other hand, free from the issues of costs and instability observed in the enzyme itself. In this project, the utilization of 4-[(1E)ethanehydrazonoyl]benzoic acid is analyzed as an efficient mimetic for acetylcholinesterase in the esterase of acetylthiocholine chloride and its application in the development of disposable amperometric biosensor for the monitoring of carbamates and organophosphorous pesticides , as well as the detection and quantification of acetylcholine biomolecule. Structural modifications of the mimetic molecule will be investigated in order to optimize its mimetic activity and its proper immobilization on the transductor surface. (AU)