Dopamine-modified Mn-doped ZnS quantum dots fluorescence probe for the sensitive detection of tyrosinase in serum samples and living cells imaging

Abstract

Tyrosinase (TYR) plays vital roles in melanin biosynthesis and function as an important biomarker for melanoma cancer; and thus has made rapid and sensitive detections for its activity to be on urgent demands. In this study, a facile aqueous fluorescence probe based on dopamine-functionalized-Mn-doped ZnS quantum dots (Dopa-Mn:ZnS QDs) was developed to detect TYR activity. When dopamine moiety in Dopa-Mn:ZnS QDs was oxidized to dopaquinone derivative by TYR, an intra-particle photo-induced electron transfer (PET) process between Dopa-Mn:ZnS QDs and dopaquinone moiety takes place, and as a result, the fluorescence is quenched. Quantitative evaluation of TYR activity was studied in terms of the relationship between fluorescence quenching efficiency and TYR activity. The probe could detect TYR in a broad linear range of up to 1620UL−1 with a low detection limit of 1.82UL−1. It was then applied to detect TYR in chicken serum samples, in which, TYR could be recovered by 88.3–100.7%. Finally, the probe demonstrated low cytotoxicity as evaluated by MTT assay and successfully applied to intracellular imaging of A549 cells. This study has indicated potential applications of Dopa-Mn:ZnS QDs probe in monitoring TYR-associated diseases, clinical diagnostics, and drug discovery.