A handheld plug-and-play microfluidic liquid handling automation platform for immunoassays

Lab-on-a-chip technologies and microfluidics have pushed miniaturized liquid handling to unprecedented precision, integration, and automation, which improved the reaction efficiency of immunoassays. However, most microfluidic immunoassay systems still require bulky infrastructures, such as external pressure sources and pneumatic systems, and complex manual tubing and interface connections, which prevent plug-and-play operation at the point-of-care (POC) settings. Here we present a fully automated handheld general microfluidic liquid handling automation platform with a plug-and-play ‘clamshell-style’ cartridge socket, a miniature electro-pneumatic controller, and injection-moldable plastic cartridges. The system could achieve multi-reagent switching, metering, and timing control on the valveless cartridge using electro-pneumatic pressure control. As a demonstration, a SARS-CoV-2 spike antibody sandwich fluorescent immunoassay (FIA) was performed on an acrylic cartridge without human intervention after sample introduction. The assay shows a low limit of detection comparable to clinical-grade enzyme-linked immunosorbent assays (ELISA). The system could also operate as a 6-port pressure source for external microfluidic chips. A rechargeable battery with a 12V 3000mAh capacity can power the system for 42 hours. The footprint of the system is 16.5×10.5×7 cm, and the weight is 801g, including the battery. The system can find many other POC and research applications requiring complex liquid manipulation, such as molecular diagnostics, cell analysis, and on-demand biomanufacturing.