A novel self-powered electrochemical sensor based on zinc-air battery for thrombin detection.

As an emerging sensing mode, self-powered electrochemical sensor (SPES) has gained much attention for its advantages of without external power supply and portable detection. However, developing SPES with enhanced output signals and anti-influence characteristics is still a challenge. To address these issues, herein, a novel zinc-air battery (ZAB)-based SPES with aptamer as a specific recognition element was constructed. In this case, bimetallic Fe/Ni and N co-doping carbon and in-situ grown carbon nanotubes (Fe-Ni/N-C/CNT) was synthesized by mixing Fe, Ni precursors with previously prepared ZIF-8. Under neutral conditions, Fe-Ni/N-C/CNT exhibits a high half-wave potential of 0.831 V (vs. RHE) and the ZAB assembled with Fe-Ni/N-C/CNT as an air cathode generates a considerable maximum peak power density (Pmax) of 84.1 mW cm-2. As a concept, thrombin (TB) was selected as a detection target, a "signal-off" SPES based on the interfacial steric hindrance effect generated by aptamers structure bending while capturing the target was constructed with Pmax as a sensing signal. Pmax values of the prepared ZAB-based SPES show a good linear relationship with logarithm of TB concentrations, accompanied by a linear range from 2 × 10-4 nM to 2 × 10-2 nM, and a detection limit of 66.7 fM (LOD). The constructed ZAB-based SPES shows good anti-interference ability, stability, and reproducibility, making it feasible and efficient in practical applications. Furthermore, this SPES strategy displays a promising generalizability for other targets detection by replacing the aptamers modified on the sensing cathode surface.