Detection of Tyrosinase Activity and Inhibitor Validation Based on N-GQDs Fluorescence Sensor

Tyrosinase inhibitors have the ability to resist melanin formation and can be used for clinical and cosmetic, so it is becoming extremely crucial to search a rapid and effective method for detecting t the activity of tyrosinase. In this study, a sensing probe based on Nitrogen-doped graphene quantum dots (N-GQDs) were prepared with carbamide and citric acid. Tyrosinase can oxidize dopamine to dopamine quinone, which can quench the fluorescence of N-GQDs based on the principle of fluorescence resonance energy transfer (FRET) process, and then the detection of tyrosinase activity can be achieved. The result demonstrated that the fluorescence intensity of N-GQDs was a linear correlation with the activity of tyrosinase. Wide detection linear ranges between 0.05 and 5 U/mL and high selectivity. The detection range of tyrosinase was 0.05 to 5 U/mL and LOD of 0.005 U/mL. According to the above, the fluorescence method established in this work could be successfully used for the trace analysis of tyrosinase and it was verified that KA is an inhibitor of tyrosinase.