(587d) Microfluidic ELISA Chips For Multiplex Detection Of Foodborne Pathogens

Rapid multiplex enzyme-linked immunosorbent assays (ELISAs) were performed in an array of microchannels for parallel detection of common foodborne pathogens, including Campylobacter jejuni, Escherichia coli O157:H7, and Salmonella typhimurium. The microfluidic chip was made of poly(methyl methacrylate) (PMMA) with microchannels produced by soft lithography. Because of the small microchannel size, the assay on the microfluidic chip uses only a small amount of reagents (<3 microliter each) and can be completed in less than 2.5 h. The fluorescent signal from the microchannels, which was greatly enhanced by treating the multichannel surface with poly(ethyleneimine) (PEI), can be read with a conventional microtiter plate reader. The multiplex microchannel ELISA can detect ~12 cells of Escherichia coli O157:H7 and ~200 cells of Salmonella typhimurium, 1-3 orders more sensitive than conventional ELISA on 96-well and 384-well microtiter plates. This microfluidic ELISA chip also alleviates the error caused from manual operation (pipetting). With a high degree of miniaturization, significantly reduced usage of reagents, and shortened assay time, this multiplex microfluidic ELISA chip can serve as a low-cost, reliable, high-throughput platform for detection of pathogens and toxins present in foods, drinking water, and biological samples, ensuring food safety in a cheap and efficient way.