Polyaniline-Based Highly Sensitive Microbial Biosensor for Selective Detection of Lindane

Abstract

A highly sensitive, selective, and rapid, whole-cell-based electrochemical biosensor was developed for detection of the persistent organochlorine pesticide γ-hexachlorocyclohexane (γ-HCH), commonly known as lindane. The gene linA2 encoding the enzyme γ-hexachlorocyclohexane (HCH) dehydrochlorinase (LinA2), involved in the initial steps of lindane (γ-HCH) biotransformation, was cloned and overexpressed in Escherichia coli. The lindane-biodegrading E. coli cells were immobilized on polyaniline film. The rapid and selective degradation of lindane and concomitant generation of hydrochloric acid by the recombinant E. coli cells in the microenvironment of polyaniline led to a change in its conductivity, which was monitored by pulsed amperometry. The biosensor could detect lindane in the part-per-trillion concentration range with a linear response from 2 to 45 ppt. The sensor was found to be selective to all the isomers of hexachlorocyclohexane (HCH) and to pentachlorocyclohexane (PCCH) but did not respond to other aliphatic and aromatic chlorides or to the end product of lindane degradation, i.e., trichlorobenzene (TCB). The sensor also did not respond to other commonly used organochlorine pesticides like DDT and DDE. On the basis of experimental results, a rationale has been proposed for the excellent sensitivity of polyaniline as a pH sensor for detection of H+ ions released in its microenvironment.

<i>Escherichia coli</i> as a Model Organism and Its Application in Biotechnology

“…In the literature, there are several reports where E. coli-based biosensors have been successful for detecting diferent traits: oxidants [72,73], DNA damaging compounds [74], membrane-damaging compounds [75], protein-damaging compounds [76], aromatic compounds [77][78][79], xenobiotics [80], antibiotic panels using reporter strains without antibiotic selection [81], etc. The only limitation is the available sensor module and the design.…”

Recent developments in recognition elements for chemical sensors and biosensors

“…In another work, a polyaniline-based microbial biosensor was fabricated [70] for detection of lindane (also known as γ-hexachlorocyclohexane), a persistent organochlorine pesticide. In this work [70], genetically-modified E. coli cells expressing γ-hexachlorocyclohexane dehydrochlorinase (LinA2), which was encoded by gene LinA2, were immobilized in a polyaniline matrix.…”

Au/Ag NPS Decorated PANI For Electrochemical and Biomedical Applications

“…Several methods for the synthesis of metal NPs have been reported by various research groups like template method, photochemical preparation, electrochemical methods or electro-deposition of metal nanoparticles, reduction of metal salts etc. [5,[17][18][19][20][21][22][23][24][25].…”