Room-Temperature Single-Molecule Mass Detection via Feedback Control of ZnO Nanowire Resonator

Nanowire resonators with near single-molecule detection sensitivity are highly susceptible to environmental factors due to their small size. Typically, these sensors require ultralow temperature conditions to function effectively, which are unfavorable for monitoring biochemical reactions. To address the technical bottleneck of insufficient stability and sensitivity of nanowire resonators at room temperature, this study utilizes ZnO nanowire (NW) resonators with larger dimensions that can operate at room temperature. By employing feedback control technology, the equivalent mass of the ZnO NW resonator is significantly reduced, thereby improving its sensitivity to -2921.42 Hz/zg. This breakthrough achieves the single-molecule detection limit at room temperature, elevating the mass detection capability to the level of an ethanol molecule (approximately 0.076 zg). Furthermore, through precise deposition of a sensitive layer on the nanowire, the ZnO NW resonator enables accurate real-time monitoring of ethanol gas molecule adsorption and desorption within a vacuum chamber. The measurement error for the mass of an individual ethanol molecule is as low as 3.9%. These findings represent a substantial advancement in single-molecule detection technology.