Biofuel cell assembled by Cu2O nanocube laccase-mimicking nanozyme based sensitive self-powered sensor to detect fungicide thiophanate-methyl

Nanozymes exhibit excellent catalytic activity and stability, making them as potential substitutes for natural enzymes with extensive applications in self-powered biosensors (SPB). In this study, Cu 2 O nanocubes (NCs) exhibiting good laccase-like activity were simply synthesized. Subsequently, a two-compartment biofuel cell (BFC) was assembled, consisting of an anodic chamber containing Cu 2 O NCs modified glassy carbon electrode (GCE) anode fueled by catechol, and a cathodic chamber featuring a bilirubin-oxidase/multi-walled carbon nanotubes (MWCNTs)/GCE biocathode. Notably, due to the ethylenediamine-like group in thiophanate-methyl (TM), which has a strong affinity for chelating the Cu(II)/Cu(I) active sites of the laccase-like of Cu 2 O NCs, the formation of Cu N bond leads to a significant inhibition of laccase-like activity and a great reduction in the open circuit potential (OCP) of the BFC. Based on this principle, an SPB was constructed to detect TM. The decline in OCP (ΔOCP) demonstrated a linear relationship with TM concentration ranging from 0.5 to 40 μM, achieving a lower detection limit of 0.11 μM (3σ/S). Moreover, the sensor exhibited no interference from other fungicides, indicating they did not affect TM detection. The as-developed sensor can be applicable to measure TM in soil and seawater samples satisfactorily. Thus, this study casts prospects for the application of nanozymes in self-powered sensors and lays the foundation for the development of fuel cells powered by phenolic pollutants in the future.