One-step synthesis of levodopa functionalized carbon quantum dots for selective detection of tyrosinase and inhibitor screening

Abstract

Tyrosinase (TYR), a key enzyme for melanin biosynthesis, is an important biomarker for melanoma, thus a biosensor that can specifically detect and image tyrosinase would be in urgent demand to diagnose tyrosinase related disease. Therefore, a novel levodopa (L-Dopa) functionalized carbon quantum dots (Dopa-CQDs) was firstly constructed and synthesized by a convenient “one-step synthesis” strategy without any modified steps, utilizing L-Dopa and urea as precursors. The Dopa-CQDs also illustrated excellent linear relationship with a wide range (0–1200 U·L−1) and a low detection limit of 7.3 U·L−1. Importantly, the nanosensor exhibited high selectivity for tyrosinase over other biological substances including various amino acids and intercellular proteases. Moreover, the Dopa-CQDs demonstrated practicability for TYR detection in human serum samples and inhibitor screening with satisfactory results. Particularly, the designed biosensor was successfully applied for intracellular TYR detection with excellent biocompatibility and cellular imaging capability, which provided a novel platform for selective detection of tyrosinase in biosystems. The novel methodology can be extended for fabricating novel biosensor for other analytes in various field, which will illustrate great importance for both fundamental research in biological systems and potential practical applications in clinical diagnosis.