Development of graphene oxide-based biosensing platforms for label-free bioelectronic detection of pathogenic microorganisms

A novel electrochemical nanogenosensor devoted to clinical analysis is reported for label-free detection of pathogenic microorganisms in the present work. The designed biosensor is composed of graphene oxide-modified disposable pencil graphite electrodes as a sensing platform. <i>Escherichia coli</i> is used as a model case. A 5'-aminohexyl-linked 22-base sequence probe representing the <i>E. coli</i> amplicon is immobilized onto sensor surfaces via carbodiimide chemistry. Hybridization is performed with denatured PCR amplicons of the bacteria. Detection is realized by transduction with the electrochemical impedance spectrometry technique. The selectivity of the designed genosensor is measured using <i>Mycobacterium tuberculosis</i> and <i>Klebsiella pneumoniae</i> sequences. Outstanding sensitivity is achieved with this genosensor array platform with a detection limit of 102 nM. This platform offers promise for rapid, simple, and cost-effective detection of various pathogenic microorganisms.