Extrinsic Antifouling Sulfur Quantum Dots: Mechanistic Insights and Their Application in Tyrosinase Detection

= 0.980 Å), effectively inhibiting the adsorption of various hydrophilic biomacromolecules. Leveraging the excellent antifouling performance of PEG-SQDs, we developed a strategy for detecting tyrosinase (TYR) activity. This strategy is based on TYR-catalyzed oxidation of l-tyrosine to melanin-like products, which efficiently quench the fluorescence of PEG-SQDs. Ultimately, a highly sensitive, selective, simple, and environmentally friendly method for TYR detection has been constructed. This method exhibits a linear response range for TYR from 0.5 to 20 U/mL, with a detection limit of 0.08 U/mL (S/N = 3). Furthermore, it enables accurate quantification of TYR activity in human serum samples, underscoring the excellent antifouling capability of PEG-SQDs in complex biological matrices. Overall, this work not only provides a novel tool for the sensitive detection of TYR but also offers new insights into the antifouling mechanism of SQDs.