Rapid and accurate detection of Escherichia coli O157:H7 in beef using microfluidic wax-printed paper-based ELISA

Escherichia coli O157:H7 is a severe foodborne pathogen that causes lots of life-threatening diseases. To search for a rapid, sensitive, portable and low-cost method detecting this pathogen, we developed a wax-printed paper-based enzyme-linked immunosorbent assay (P-ELISA) based on microfluidic paper-based analytical device (μPADs), with the whole operation time less than 3 hours and only needing 5 µl samples to detect. The limit of detection (LOD) of E. coli O157:H7 reached 104 CFU/ml, which was an order of magnitude higher than conventional ELISA (C-ELISA). LOD in artificially contaminated beef samples was 1CFU/25g after enriched culture for 8 h. This method was superior to molecular biology method in detection sensitivity and superior to C-ELISA and national standard method in detection time and cost. Thus, the established P-ELISA method has good sensitivity, specificity and repeatability. It can be suitable for point-of-care testing without expensive and bulky instruments and can also provide a platform for detecting other pathogens, especially in areas that lack advanced clinical equipment.