Non-enzymatic electrochemical detection of H2O2 using a green-synthesized rGO–liposome composite on gold thin films

Abstract

Electrochemical sensing platforms based on reduced graphene oxide (rGO) have attracted significant attention for the detection of redox-active analytes owing to their high surface area, tunable conductivity, and facile surface functionalization. In this work, we report a hydrothermal-assisted green route using the ethanolic neem leaf extract method for the synthesis of rGO and preparation of a biocompatible liposome–rGO effective sensing platform for non-enzymatic electrochemical hydrogen peroxide (H₂O₂) sensing. Liposomes were synthesized through a thin-film hydration method using egg yolk-derived lecithin and subsequently integrated with rGO to form a stable aqueous dispersion, as evidenced by zeta potential measurements. The synthesis of rGO was confirmed by XRD, Raman, UV–Vis, FTIR, and electron microscopy analyses with restored sp² carbon domains. Electrochemical performance toward H₂O₂ was evaluated using cyclic voltammetry in phosphate-buffered saline. The sensor exhibited a linear response in the concentration range of 10–90 μM with a limit of detection of 10 μM. Scan rate-dependent studies revealed diffusion-controlled, quasi-reversible electron transfer behavior, indicating efficient charge transport across the liposome–rGO/Au interface. The synergistic combination of green-synthesized rGO, biocompatible liposomes, and a gold thin-film electrode provides an environmentally benign and effective sensing platform for non-enzymatic H₂O₂ detection, demonstrating potential for future biosensing and analytical applications.