A CRISPR-based 'dam-break drainage' sensing architecture for rapid, affordable and ultrasensitive pathogen detection

Nucleic acid testing is important for infectious-disease diagnosis, but combining high sensitivity with accessible testing remains challenging. Here we show a chip-based visual detection strategy for one or two viral RNA targets that involves only sample loading, without further instrumentation or manual actuation. Target-activated CRISPR-Cas13a alters the wettability of a molecular barrier, causing liquid to cross a preset threshold and generate a dam-break drainage signal. The chip detects a single target at 10 aM within 2 min and two targets at 100 aM within 5 min, with costs of $0.20 and $0.30 per test, respectively. We further establish a practical clinical-sample workflow combining room-temperature lysis with RNase inhibition and validate the platform across 40 nasal-swab samples tested for SARS-CoV-2, influenza A virus and influenza B virus, with results concordant with RT-PCR. This threshold-based fluidic strategy provides a route towards rapid, low-cost and instrument-free molecular testing outside centralized laboratories.