| 摘要 |
Lab-on-a-disc (LOAD) point-of-care testing (POCT) system offers efficient and portable potentials for pathogenic microorganisms diagnosis. However, multifunctional and on-demand flexible manipulations of reagents are essential in LOAD POCT units. Here, a magnet regulating valve (MRV) has been successfully developed and integrated into centrifugal microfluidic chip to achieve reagents pre-storage, sequential release, reaction system block and dynamic air pressure balance. The MRV consists of a fixed magnet, a movable magnet, a silicone pad with a central hole and corresponding chamber and channel. The programmable opening and closing of MRV could be achieved through adjusting the centrifugal speed and the distance of magnets. For demonstration, silica membrane-based DNA extraction and fluorescent loop-mediated isothermal amplification (LAMP) have been confirmed as stable and feasible pathogen detection through functionalized MRVs layout. Under optimal conditions, the proposed MRVs LOAD POCT system can achieve highly sensitive detection of Salmonella Enteritidis, Escherichia coli O157:H7, and Staphylococcus aureus in spiked chicken supernatant as low as 10 CFU/mL within 40 min. The real food sample analytical results of the MRVs LOAD POCT system showed 97.92 % consistency with the plate counting method of foodborne pathogens, with an average recovery of 103.44 %. The proposed LOAD system represents a promising approach for highly sensitive DNA POCT of multiple foodborne pathogenic microorganisms in resource-limited settings. |
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