Stirring enrichment/bio-proliferation dual-amplified photoelectrochemical phage biosensor for selective and sensitive detection of foodborne pathogens.

Abstract

Food pathogens pose significant threats to public health, so it is urgent to explore reliable, sensitive, and on-site detection approaches to address this challenge. Herein, a novel stirring enrichment/bio-proliferation dual-amplified photoelectrochemical phage (SEBP-PECP) biosensor is ingeniously proposed for foodborne pathogens detection, with Escherichia coli O157:H7 (E. coli) serving as a model toxic pathogen strain. The biosensor is designed and fabricated by integrating the self-assembled TiO2 nanorods (TiO2 NRs) and phages against E. coli onto a conductive glassy electrode. In the absence of E. coli, the TiO2 NRs generated strongly photoelectric current signal in the case of ascorbic acid and visible light. Upon the addition of E. coli, the bacteria were enriched on the electrode through the specific phages-bacteria binding and further proliferated in an E. coli growth medium, thus rusulting in a remarkable decline in the signal. Within 40 min, the concentration of E. coli exhibited a linear relationship with the decrease of the photoelectric current signal in range of 101-108 CFU/mL, and a detection limit of 5 CFU/mL. The high sensitivity was mainly attributed to the amplified current change value enabled by the synergistic effects of stirring enrichment and bio-proliferation. The SEBP-PECP biosensor was applied to the E. coli determination in food sample with recoveries of 93.0-102 % and relative standard devision (RSD) of 4.5 %-9.6 %. The biosensor is rapid, in-situ, sensitive and selective, providing a prominent approach for the detection of foodborne pathogens in real samples.