Enzyme-Free Hydrogen Peroxide Sensing Based on Heterogeneous SnO2@CuO/CF via Interfacial Engineering

Hydrogen peroxide (H2O2) is a major messenger molecule in cellular signal transduction. It is critical to detect cellular secreted H2O2 in situ for clinical diagnosis and biomedical research. Therefore a simple, fast, sensitive, and cost-effective hydrogen peroxide detection method is needed.In this study, copper foam (CF) was used as copper source and conductive substrate, the electrochemical sensor SnO2@CuO/CF is prepared to detect H2O2 secreted by living cells. High resolution transmission electron microscopy (HRTEM), X-ray diffraction, Mott Schottky curves and X-ray photoelectron spectroscopy demonstrate the successful formation of SnO2@CuO heterostructure. Theoretical calculations confirm that SnO2@CuO heterostructure facilitates the adsorption of H2O2. The designed SnO2@CuO/CF sensor shows good sensing performance for H2O2. Under optimal conditions, the designed sensor shows a relatively wide linear range to H2O2 concentration from 1μM to 13.88 mM, with high sensitivity (5100μA·mM−1·cm−2) and low detection limit (0.13μM). Cytotoxicity experiments prove that the sensor has good biocompatibility and the prepared sensor is successfully used to detect H2O2 released by HeLa cells.With superior sensitivity, anti-interference ability, and reproducibility, SnO2@CuO /CF shows the potential application of H2O2 monitoring in the field of biomedical and clinical diagnosis. This study provides a new platform for the development of highly sensitive H2O2 electrochemical sensors in practical applications.