Ultrasensitive peptide-based multiplexed electrochemical biosensor for the simultaneous detection of Listeria monocytogenes and Staphylococcus aureus.

Abstract

Anovel electrochemical biosensor is reportedfor simultaneous detection of two of the most common food-borne pathogens: Listeria monocytogenes and Staphylococcus aureus. Thebiosensor is composed of an array of gold nanoparticles-modified screen-printed carbon electrodes on which magnetic nanoparticles coupled to specific peptides were immobilized via streptavidin-biotin interaction. Taking advantage of the proteolytic activities of the protease enzymes produced from the two bacteria on the specific peptides, the detection was achieved in 1min. The detection was realized by measuring the percentage increase of the square wave voltammetric peak current at 0.1V versus aAg/AgCl reference electrode in ferro/ferricyanide redox couple after incubation with the bacteria protease. The integration of the specificity of the bacterial enzymes towards their peptide substrates with the sensitivity of the electrochemical detection on the sensor array allows the rapid, sensitive and selective quantification of the two bacteria. Outstanding sensitivities were achieved using this biosensor array platform with limit of detection of 9CFUmL-1 for Listeria monocytogenes and 3CFUmL-1 for Staphylococcus aureus. The multiplexing capability and selectivity of thearray voltammetric biosensor were demonstrated by analysing samples of Staphylococcus aureus, Listeria monocytogenes or E. coli and also containing a mixture of two or three bacteria. Using this biosensor, the two bacteria were successfully quantified simultaneously in one step without the need for DNA extraction or amplification techniques. This platform offers promise for rapid, simple and cost-effective simultaneous detection of various bacteria. Graphical abstract.