Escherichia coli-functionalized magnetic nanobeads as an ultrasensitive biosensor for heavy metals

The detection of traces of heavy metals in real environmental samples is a difficult task. In this work, we combined the advantages of nanobeads’ (NBs) properties with the simplicity of the layer-by-layer procedure, along with the use of micro-organisms as bioreceptors, for the elaboration of a novel electrochemical biosensor based on nanocomposite films. The whole cells (Escherichia. coli) K-12 used as bioreceptors were fixed onto a surface of indium-tin-oxide (ITO) glass with and without NBs and/or polyelectrolyte multilayers (PEM). Using the electrochemical impedance spectroscopy (EIS) technique, cadmium and mercury were detected.