An optical biosensor from green fluorescent Escherichia coli for the evaluation of single and combined heavy metal toxicities.

Dedi Futra,Salmijah Surif,Lee Heng,Asmat Ahmad,Tan Ling

doi:10.3390/s150612668

Abstract

A fluorescence-based fiber optic toxicity biosensor based on genetically modified Escherichia coli (E. coli) with green fluorescent protein (GFP) was developed for the evaluation of the toxicity of several hazardous heavy metal ions. The toxic metals include Cu(II), Cd(II), Pb(II), Zn(II), Cr(VI), Co(II), Ni(II), Ag(I) and Fe(III). The optimum fluorescence excitation and emission wavelengths of the optical biosensor were 400 ± 2 nm and 485 ± 2 nm, respectively. Based on the toxicity observed under optimal conditions, the detection limits of Cu(II), Cd(II), Pb(II), Zn(II), Cr(VI), Co(II), Ni(II), Ag(I) and Fe(III) that can be detected using the toxicity biosensor were at 0.04, 0.32, 0.46, 2.80, 100, 250, 400, 720 and 2600 μg/L, respectively. The repeatability and reproducibility of the proposed biosensor were 3.5%–4.8% RSD (relative standard deviation) and 3.6%–5.1% RSD (n = 8), respectively. The biosensor response was stable for at least five weeks, and demonstrated higher sensitivity towards metal toxicity evaluation when compared to a conventional Microtox assay.

Highlights

Toxic pollution occurs when hazardous chemicals are discharged and spread throughout the world, due to the rapid pace of industrial development
We describe the fabrication of toxicity biosensor using recombinant green fluorescent protein (GFP) E. coli immobilized on the cellulose nitrate membrane, covered with a layer of
In the absence of a toxicant, the immobilized GFP cell resulted in a significant fluorescence response at 485 ± 2 nm

Summary

Introduction

Toxic pollution occurs when hazardous chemicals are discharged and spread throughout the world, due to the rapid pace of industrial development. There are more than 100 toxicants (metals) in the environment having a detrimental effect on human and biological systems, and 23 of these are heavy elements. They are not detrimental to human health and biological systems, as a matter of fact; they are essential towards a healthy life e.g., iron, copper, manganese, and zinc. These elements are functionalized as catalysts of biochemistry reactions in cells, enzyme stability, regulation of gene expression, and regulatory of osmosis pressure for membranes [3].

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