Sub-Femtomolar Drug Monitoring via Co-Calibration Mechanism with Nanoconfined DNA Probes

Synthetic drugs have fundamentally reshaped the illicit drug market due to their low cost, ease of production, and rapid manufacturing processes. However, current drug detection methods, reliant on complex instruments, face limited applicability and often neglect the influence of pH fluctuations, leading to potential bias and unreliable results. Herein, we proposed co-calibration mechanism of DNA probes in nanoconfined channel to achieve significantly enhanced target signal recognition in sweat range pH 3.0 ~ 8.0. The limit of detection (LOD) lows to 3.58 fM in artificial sweat with wide linear response range10 ³  ~ 10 ⁸ fM. Compared to the single DNA probe, the co-calibrated dual-DNA probes exhibits a broader linear response range, primarily attributed to the synergistic effects of surface wettability regulation and the hydrion capture in nanoconfined channel, which in turn reduces signal interference in proton transport. The linear response range has doubled, and the detection sensitivity has improved by 4 ~ 5 orders of magnitude compared to existing drug detection methods. This co-calibration strategy expands the application scope of aptamer-based composite probes, offering a novel approach for ultra-sensitive drug detection and showing significant potential in sweat sensing and drug monitoring fields.