Carbon-dot wrapped ZnO nanoparticle-based photoelectrochemical sensor for selective monitoring of H 2 O 2 released from cancer cells.

This study reports on a simple approach for the fabrication of an electrode modified with biocompatible C-dot wrapped ZnO nanoparticles for selective photoelectrochemical monitoring of H2 O2 released from living cells. The biocompatibility of the ZnO nanoparticles was confirmed through in-vitro cellular testing using the MTT assay on Huh7 cell lines. The ZnO nanoparticles wrapped with dopamine-derived C-dots possess numerous catalytically active sites, excessive surface defects, good electrical conductivity, and efficient separation ability of photo-induced electrons and holes. These properties offer highly sensitive and selective non-enzymatic photo-electrochemical monitoring of H2 O2 released from HeLa cells after stimulation with N-formylmethionyl-leucyl-phenylalanine. The sensor has a wide linear range (20-800 nM), low detection limit (2.4 nM), and reliable reproducibility, this implying its suitability for biological and biomedical applications. Graphical abstract Schematic of the fabrication of ZnO nanoparticles by using a plant extract as a reducing agent. Wrapping of ZnO with C-dots enhances the photoelectrocatalytic efficacy. Sensitive and selective photoelectrochemical monitoring of H2 O2 released from cancer cells is demonstrated.