A facile one-pot synthesis of copper sulfide-decorated reduced graphene oxide composites for enhanced detecting of H2O2 in biological environments.

The high levels of H2O2 are closely associated with cancer and progressive neurodegenerative diseases, such as Parkinson's disease. In this study, we developed a novel CuS nanoparticle-decorated reduced graphene oxide-based electrochemical biosensor for the reliable detection of H2O2. The new electrocatalyst, CuS/RGO composites was successfully prepared by heating the mixture of CuCl2 and Na2S aqueous solutions in the presence of PVP-protected graphene oxide at 180 °C. A potential application of CuS/RGO composite-modified electrode as a biosensor to monitor H2O2 has been investigated. The steady-state current response increases linearly with H2O2 concentration from 5 to 1500 μM with a fast response time of less than 2 s. The detection limit (3σ) for determination of H2O2 has been estimated to be 0.27 μM, which was lower than certain enzymes and noble metal nanomaterial-based biosensors. In addition, the study of storage time on the amperometric response of the sensor indicates super stability. Due to these remarkable analytical advantages, the as-made sensor was applied to determine the H2O2 levels in human serum and urine samples and H2O2 released from human cervical cancer cells with satisfactory results. These results demonstrate that this new nanocomposite with the high surface area and electrocatalytic activity is a promising candidate for use as an enhanced electrochemical sensing platform in the design of nonenzymatic biosensors.