Fast, inexpensive, and multiplexed detection of multiple nucleic acids is of great importance to human health, yet it still represents a significant challenge. Herein, we propose a nucleic acid testing platform, named MiCaR, which couples a microfluidic device with CRISPR-Cas12a and multiplex recombinase polymerase amplification. With only one fluorescence probe, MiCaR can simultaneously test up to 30 nucleic acid targets through microfluidic space coding. The detection limit achieves 0.26 attomole, and the multiplexed assay takes only 40 min. We demonstrate the utility of MiCaR by efficiently detecting the nine HPV subtypes targeted by the 9-valent HPV vaccine, showing a sensitivity of 97.8% and specificity of 98.1% in the testing of 100 patient samples at risk for HPV infection. Additionally, we also show the generalizability of our approach by successfully testing eight of the most clinically relevant respiratory viruses. We anticipate this effective, undecorated and versatile platform to be widely used in multiplexed nucleic acid detection.
Traditional diagnostic strategies for infectious disease detection require benchtop instruments that are inappropriate for point-of-care testing (POCT). Emerging microfluidics, a highly miniaturized, automatic, and integrated technology, are a potential substitute for traditional methods in performing rapid, low-cost, accurate, and on-site diagnoses. Molecular diagnostics are widely used in microfluidic devices as the most effective approaches for pathogen detection. This review summarizes the latest advances in microfluidics-based molecular diagnostics for infectious diseases from academic perspectives and industrial outlooks. First, we introduce the typical on-chip nucleic acid processes, including sample preprocessing, amplification, and signal read-out. Then, four categories of microfluidic platforms are compared with respect to features, merits, and demerits. We further discuss application of the digital assay in absolute nucleic acid quantification. Both the classic and recent microfluidics-based commercial molecular diagnostic devices are summarized as proof of the current market status. Finally, we propose future directions for microfluidics-based infectious disease diagnosis.