An integrated self-heating recombinase polymerase amplification lateral flow strip biosensor for quantification of enterohemorrhagic Escherichia coli O157:H7

The early and precise detection of enterohemorrhagic Escherichia coli (EHEC) O157:H7, a major foodborne pathogen, is crucial to prevent outbreaks and ensure food safety. However, traditional diagnostic methods are often time-consuming, labor-intensive, and require sophisticated laboratory facilities, making them less feasible for point-of-care testing. Here, we present a novel, self-heating recombinase polymerase amplification (RPA)based integrated lateral flow strip biosensor for the efficient detection of EHEC O157:H7. The self-heating mechanism based on calcium oxide provides a stable and optimal external temperature for RPA, avoiding the use of external power sources or complex temperature control devices. In addition, the color intensity of the test line of the lateral flow strip can be uploaded to the ImageJ software by taking photos, and the quantitative detection of EHEC O157:H7 can be realized by analyzing the gray value. Our results demonstrate that this biosensor has a visual detection limit of 1 x 102 CFU/mL and an analytical limit of detection of 36.23 CFU/mL for EHEC O157:H7, offering rapid detection within 30 min. Furthermore, the biosensor displayed exceptional specificity and exhibited high accuracy. The RSD of three varying concentrations were respectively 5.39 %, 3.85 % and 4.82 %.