Ratiometric and light-up near-infrared fluorescent DCM-based probe for real-time monitoring endogenous tyrosinase activity

Tyrosinase (TYR), which is regarded as a significant biomarker of melanoma cancer, plays a crucial but incompletely understood role in cellular biochemistry and etiology. In this work, we report a TYR activatable NIR fluorescent probe DCM-1, which is composed of dicyanomethylene-4H-pyran (DCM) unit as the NIR fluorescence reporter, amide bond specific for TYR cleavage, and phenol group as the triggered moiety. The activation of DCM-1 by endogenous TYR can induce a remarkable fluorescence red shift from 548 to 660 nm, allowing for ratiometric and light-up NIR response to real-time track TYR activity. Besides, DCM-1 exhibits extraordinary features, such as excellent sensitivity, high selectivity, and high photostability. In vitro experiments by confocal laser scanning microscopy reveals that the spatial-temporal information of TYR in B16 melanoma cancer cells can be achieved by the probe DCM-1. Thus, this enzyme-activatable NIR probe can be a powerful tool for elucidating the roles of TYR in biological systems.