Colorimetric H2O2 Detection Using Ag-Nanoparticle-Decorated Silica Microspheres
In view of the importance of convenient and rapid H2O2 detection for biological analysis, we herein propose Ag nanoparticle (NP)-decorated silica microspheres as a probe for instant and non-enzymatic on-site colorimetric detection of H2O2. The surface hydroxyl groups of silica microspheres were reacted with (3-mercaptopropyl)trimethoxysilane to afford thiolated microspheres that subsequently bind Ag NPs. The oxidation of residual –SH groups on the silica surface to –S–S– moieties in the presence of H2O2 induces the aggregation of decorated microspheres and is accompanied by a color change. Sensor response is found to be proportional to H2O2 concentration in the range from 100[Formula: see text]nM to 1[Formula: see text]mM, with UV–Vis and colorimetric detection limits determined as 10[Formula: see text][Formula: see text]M and 10[Formula: see text][Formula: see text]M, respectively. The developed platform is successfully used to detect H2O2 in simulated human urine and is, therefore, concluded to be sufficiently stable and selective for practical applications.