Synthesis of ultra-stable fluorescent carbon dots from polyvinylpyrrolidone and their application in the detection of hydroxyl radicals.

Highly biocompatible and highly photostable fluorescent carbon dots (C dots) were obtained through a simple and nontoxic one-pot hydrothermal method. Polyvinylpyrrolidone, a common and low-cost biocompatibility reagent, was used as the only carbon source for the first time. The resulting water-soluble C dots showed a quantum yield of up to 23.58% with low cytotoxicity, favorable photoluminescent properties, and good photostability. Importantly, the fluorescence intensities of the C dots were quite stable in high-salt conditions and over a broad pH range (3.0-10.5). The as-prepared C dots have been demonstrated to be an excellent probe for hydroxyl radicals sensing based on the fluorescence quenching with great sensitivity and specificity. This opens up a new application field for C dots.