Microfluidic Enrichment of Intact Viral Particles by Stoichiometric Balanced DNA Computation

Applications in health diagnostics, community safety and environmental monitoring require selective and quantitatively accurate active viral load assessment. Herein, we report a microfluidic enrichment strategy to separate intact SARS-CoV-2 particles by the AND logic gate with the inputs of cholesterol oligonucleotides for the envelope and aptamers for the spike. Considering the unequal quantity of endogenous spike and lipid membrane on SARS-CoV-2, a dual-domain binding strate-gy based on two aptamers targeting two spike domains was applied to balance the spike-envelope stoichiometric ratio. With the stoichiometric balanced DNA computation and the promoted microscale mass transfer of herringbone chip, the devel-oped strategy enables sensitively detection of pseudotyped SARS-CoV-2 with a limit of detection as low as 34 active virion/μL, but also distinguishes from their inactive counterparts, other nontarget viruses and free spike. Moreover, the captured viral particles can be released through DNase I treatment with up to 90 % efficiency, which is fully compatible with virus culture and sequencing. Overall, the developed strategy not only 100% identifies healthy donors (n = 8) and patients (n = 14) with SARS-CoV-2 infection, but also provides a novel perspective on regulating of stoichiometric ratio to achieve a more biologically appropriate DNA computation.