A label-free luminescent assay for tyrosinase activity monitoring and inhibitor screening with responsive lanthanide coordination polymer nanoparticles

Abstract

In this work, a label-free, selective, and sensitive luminescent sensing platform was established for tyrosinase (TYR) activity monitoring and its inhibitor screening using one kind of lanthanide coordination polymer nanoparticles AMP-Tb/Ag+. By taking advantage of the specific binding and redox properties of Ag+ incorporated into the AMP-Tb network and dopamine (DA) as the product of the model substrate tyramine, the enzymatic reaction and the signal change of the sensing platform was effectively linked. The cooperative effect of a weakened energy transfer from AMP to Tb3+ by altering the electronic structure of Ag+ and an efficient photoinduced election transfer (PET) process caused by dopaquinone facilitated the luminescence quenching of Tb3+. Thus, this luminescent sensing platform could be employed for quantitative evaluation of TYR activity. There was a good linear range for TYR activity from 0.08 to 0.20 U mL-1 with a low detection limit of 0.004 U mL-1. Furthermore, this assay was successfully applied to accurate determination of TYR activity in human serum samples and efficient screening of TYR inhibitors. Considering unique spectral characteristics of lanthanides along with operation simplicity and superior analytical performance, this sensing platform is very promising in clinical diagnosis and drugs screening for TYR-associated diseases.