Au anchored three-dimensional macroporous NiO@CuO inverse opals for in-situ sensing of hydrogen peroxide secretion from living cells

Abstract

Cost-effective and flexible electrochemical biosensors emerged as a powerful platform for In-situ detecting of hydrogen peroxide (H2O2) in living cells. How to design the high-performance biosensor for accurately monitoring the trace H2O2 releasing from the living cells is critical. In this work, a series of three-dimensional CuO inverse opals coated with NiO nanoflakes (3DIO NiO@CuO) and Au nanoparticles (NPs) are developed for non-enzymatic tracking of H2O2 in the living cells. Well-ordered macroporous 3DIO CuO skeleton provides the scaffold for NiO coating and fast passway for target analytes diffusing. NiO nanoflakes with larger surface-to-volume ratio and Au NPs catalyst are further assembled to improve the sensing performance. The optimal Au modified 3DIO NiO@CuO electrode exhibites sensitivities of 650.2 μA mM−1 cm-2 (20 nM–20 μM) and 432.7 μA mM−1 cm-2 (21 μM–2 mM) with the detection limit as low as 3.7 nM in physiological environment. The electrode also exhibits excellent anti-interference and reproducibility. Owing to the superior performance in detecting H2O2, the electrode is successfully applied in In-situ and low cytotoxicity determining H2O2 secretion released from living cells. All these results indicated that the as-designed electrode is promising in real-time monitoring H2O2 for evaluation oxidative stress of living cells.