A fluorine-doped tin oxide electrode modified with gold nanoparticles for electrochemiluminescent determination of hydrogen peroxide released by living cells

An electrogenerated chemiluminescence (ECL) based method is described for the determination of hydrogen peroxide (H2O2) released by living cells. It is making use of a fluorine-doped tin oxide (FTO) electrode that was modified with gold nanoparticles (AuNPs). The AuNP-FTO was fabricated by electrodeposition of AuNP on the surface of the FTO electrode and characterized by scanning electron microscopy and electrochemical techniques. The AuNP-FTO exhibits a significant electrocatalytic activity towards luminol-based ECL system compared to a bare FTO. The calibration plot covers the 10 nM to 1 μM H2O2 concentration range, with a 8 nM detection limit (at a signal-to-noise ratio of 3). The method enabled (a) the monitoring of drug-stimulated production of H2O2 released by living cells including RAW 264.7 macrophage cells and HeLa cells; and (b) the determination of inhibitors of H2O2 secretion. The method, due to strong signal amplification by AuNPs, provides a viable tool for determination of H2O2 in biological systems.