Highly chemoselective fluorescent probe for the detection of tyrosinase in living cells and zebrafish model

•FT-3 exhibits an excellent signal to noisy ratio, ROS-resistant and highly chemoselective.•FT-3 shows favourable cellular uptaken and was successfully employed for monitoring tyrosinase in different living cells.•FT-3 was successfully employed for monitoring tyrosinase activity in zebrafish larvae. Tyrosinase (Tyr) is known as an important cancer-related biomarker, which shows significant over-expression in malignant tumor cells, such as melanoma. Developing highly sensitive and selective fluorescent probe for monitoring tyrosinase in living system is still challenging. In this project, we report a novel fluorescein-based highly chemoselective fluorescent probe (FT-3) capable of tracking tyrosinase in vitro and in vivo in turn-on model. FT-3 contains a 3-hydroxybenzyloxy unit as the tyrosinase recognition moiety, which precluded from interference of other competitive omnipresent ROS in living system and realized the highly chemoselective detection of tyrosinase. Furthermore, the probe worked in aqueous solution and showed more than 24-fold fluorescence enhancement in the presence of tyrosinase, which endows FT-3, an excellent signal to noisy ratio. In addition, we have successfully employed FT-3 to monitoring tyrosinase activity in different living cells and zebrafish models. We believe that our newly designed fluorescent probe will provide an alternative for tracking tyrosinase in complex living system.