A high-performance amperometric sensor based on a monodisperse Pt-Au bimetallic nanoporous electrode for determination of hydrogen peroxide released from living cells

Abstract

A neotype electrochemical sensor based on a three-dimensional nanoporous gold (3D-NPG) electrode decorated with ultra-thin platinum nanoparticles (Pt NPs) was fabricated for high-performance electrocatalysis and sensitive determination of hydrogen peroxide (H₂O₂) released from pheochromocytoma (PC12) cells. The monodisperse Pt-Au bimetallic nanoporous (Pt-Au-BNP) electrode prepared by cyclic voltammetry electrodepositing monolayer Pt NPs on the surface of the 3D-NPG electrode was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectroscopy (EDS). Amperometric response for H₂O₂ measurement was chosen at an applied potential of - 0.4 V. Upon optimal conditions, the wide linear range for the amperometric determination of H₂O₂ was from 0.05 μM to 7.37 mM, with a limit of detection (S/N = 3) of 1.5 × 10^-8 mol/L and a high sensitivity of 1.125 μA μM^-1 cm^-2, certifying the large electrocatalytic action of the Pt-Au-BNP electrode. The proposed sensor has been successfully applied to the dynamic determination of H₂O₂ released from PC12 cells (from which the H₂O₂ generated by each cell was about 52.5 amol) with negligible interference. Thus, the proposed new electrochemical sensor displays potential applications for the dynamic, real-time monitoring of key small molecules secreted by living cells, further deepening the understanding of cell behavior stimulated by foreign materials. Graphical Abstract .

Keywords: H2O2; Monodisperse Pt–Au bimetallic nanoporous electrode; PC12 cells; Three-dimensional nanoporous gold.