E. coli O157:H7 has become a crucial foodborne pathogen with certain morbidity and mortality. However, the available methods still face the significant challenges including the improvement of detection specificity and sensitivity for real sample analysis. Herein, a microfluidic chemiluminescence biosensor based on a multiple signal amplification strategy was developed for rapid and ultrasensitive detection of E.coli O157:H7. The microfluidic device was consisted of an upstream snake-shape mixing channel and a downstream ship-shape microcavity with micropillar array for high efficient mixing of CL reagents, sufficient CHA amplification reaction and CL reaction. The multiple signal amplification was achieved by bacteria competitively bind to trigger catalytic hairpin assembly (CHA) and HRP-Au NPs catalyzed CL reaction. Based on the platform, the detection of target bacteria is converted to the detection of nucleic acid with a limit detection down to 130 CFU/mL, which is better or comparable to previously reported biosensors. Moreover, the whole analysis time was about 1.5 h with only 10 μL of sample. The biosensor exhibited an excellent recovery rate ranged from 90.0% to 110.0% and good selectivity to the target bacteria. Overall, this developed biosensor is a promising tool for ultrahigh sensitive and rapid detection of foodborne pathogens.
Keywords: Au NPs; Catalytic hairpin assembly; Chemiluminescence; E. coli O157:H7; Microfluidic chip.
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