Direct reduction of HAuCl4 for the visual detection of intracellular hydrogen peroxide based on Au-Pt/SiO2 nanospheres

It is attractive but remains challenging to develop nanomaterials-based methods to realize the colorimetric detection of ultratrace biological analytes. In this work, an HAuCl4-H2O2 system was developed for the visual detection of intracellular hydrogen peroxide (H2O2) based on the Au-Pt/SiO2 sensing platform. Owing to their excellent intrinsic peroxidase-like activity, Au-Pt/SiO2 nanospheres were introduced to catalyze the decomposition of H2O2 and then directly reduce HAuCl4 into gold nanoparticles (Au NPs) for the naked-eye detection. The produced Au NPs behaved color variations from light purple to wine red as H2O2 concentration increased. Under the optimal conditions, this strategy showed excellent sensitivity for H2O2 with a detection limit of 0.1 nM by naked-eye readout and 0.1 pM by UV-vis spectrometer (S/N = 3), as well as acceptable selectivity for H2O2, which could meet the demand for the detection of H2O2 in biological systems. The method was further validated by the determination of H2O2 in HeLa cells with low cellular cytotoxicity. Thus, this strategy would provide simple and sensitive detection of H2O2 in biological systems, revealing the potential application in clinical, biological and environmental researches. 2017 Elsevier B.V. All rights reserved.