Abstract
Affordable, sensitive, and simplified DNA/RNA detection is important for disease diagnosis and enables timely medical intervention measures. Usually, high sensitivity depends on expensive instruments and sophisticated procedures, making sensitivity contradict affordability and simplicity. Here, we proposed an ultra-sensitive single-tube biosensor (USTB) where users can visually detect targets by observing the liquid motion state in a glass tube. The developed instrument-free USTB performed low-cost ($0.1), fast (1 min), and ultra-sensitive detection for both the DNA/RNA fragments (≤1 aM) and the clinical positive samples, which commercial reverse transcription polymerase chain reaction (RT-PCR) and PCR kits could not effectively recognize. Furthermore, USTB is promising to be easily applied to detect other-type biomarkers by the designed smart sensing unit.