A turn-on fluorescent probe for sensitive detection of ascorbic acid based on SiNP–MnO2 nanocomposites

Abstract

Ascorbic acid plays a crucial role in biochemical processes as a scavenger for preventing oxidative damage. Herein, a sensitive and selective fluorescent biosensor for the detection of ascorbic acid was proposed based on green-emission fluorescent silicon nanoparticles (SiNPs) and bovine serum albumin (BSA) templated-MnO₂ nanosheets. Green-emission fluorescent SiNPs have been synthesized by a facile one-pot reduction reaction at room temperature by using DAMO and 3-hydroxytyramine hydrochloride as the silicon source and the reactants, respectively. The fluorescence of the SiNPs could be effectively quenched by MnO₂ nanosheets. When ascorbic acid is introduced, the MnO₂ nanosheets are reduced to Mn²⁺ ions by ascorbic acid, resulting in the fluorescence recovery of SiNPs. This sensing system exhibits a good linear range for ascorbic acid detection from 1 to 400 μM with a detection limit of 0.102 μM. Meanwhile, the detection system also exhibits high selectivity against other possible co-existing species. The present sensor was successfully applied for the detection of ascorbic acid in a commercially available vitamin C supplement, suggesting this sensing system holds great potential in food safety and disease diagnosis.