A Bioinspired Microfluidic Nucleic Acid Sensing Platform for Rapid and Simultaneous Screening of Viral Respiratory Infections

In the postpandemic era, to tackle the engineering challenge from the concurrent outbreak of routine and emerging viral respiratory infections, microfluidic-chip-based point-of-care screening of multiple pathogens becomes essential for decentralized epidemic diagnosis and management. Toward real-world POCT, state-of-the-art microfluidic diagnostic devices are limited by the in-plane design of the fluidic circuit, which highly relies on external pumping apparatus for sample injection and distribution and thus greatly hampers their portability and accessibility. In this work, inspired by the pump-free water absorption mechanism of plant root hairs, we report a self-powered hand-held microfluidic sensing platform for simultaneous and rapid nucleic acid screening of viral respiratory pathogens, such as influenza A and B and SARS-CoV-2. This design lifts the liquid distribution port out of the principal plane of the microfluidic circuit to harness the power of gravity for sample injection and equal distribution. The root-hair-like liquid distribution channels enable fast and directional transport of limited biological specimen. Cascaded recombinase polymerase amplification and lateral flow assay yield rapid visual readout for the three pathogens in 40 min with a competitive detection sensitivity as low as 0.18 copies/μL, close to the detection limit of qPCR (gold standard). For real clinical specimens, retrospective research shows a sensitivity of 93.2% and a specificity of 97.7%. From an economic perspective, a unit cost down to 1.4 USD per test can generally be attained. This design leverages biomimetic structures to boost pump-free liquid transport for rapid and cost-efficient POCT for decentralized diagnostics, particularly in infrastructure-deficient areas.