A magnet-actuated microfluidic array chip for high-throughput pretreatment and amplification and detection of multiple pathogens

The outbreak of global infectious diseases has posed a significant threat to public health, requiring the rapid and accurate diagnosis of pathogens promptly for the society to implement immediate control measures to prevent widespread pandemics. In this work, a magnet-actuated microfluidic array chip (MMAC) is developed with integrated sample processing and nucleic acid amplification for the rapid detection of multiple pathogens by loop-mediated isothermal amplification. In comparison to previous works, where fluid control was dependent on external equipment or finger-based manual pressing, the fluid control of the MMAC is realized by magnetically actuating a ferric oxide (Fe3O4) doped polydimethylsiloxane (PDMS) layer that separates the sample from the LAMP reagent in a high-throughput manner, which not only reduces the complexity of fluid control but also enhances the repeatability of detection by eliminating variations in operation by different users. Examination with a testing sample containing Salmonella typhimurium and Escherichia coli showed high specificity for pathogen detection without cross-contamination. The lowest detection concentration was 5.2 copies per μL for Salmonella typhimurium with a detection time of 60 min. The proposed method demonstrated the simultaneous detection of multiple pathogens, which is potentially helpful in applications of immediate diagnosis.