A turn-on fluorescence assay of tyrosinase activity based on an enzyme-triggered hydroxylation of phenol for conformation of silicon nanoparticles

Evolution of fluorometric sensing methods has brought an enormous opportunity and exhibited novel potentials for enzymatic activities determination. Herein, we have established an accurate and straightforward fluorescent sensing approach for tyrosinase (TYR) activity based on the formation of fluorescent silicon nanoparticles (Si NPs). Influenced by TYR-induced hydroxylation of phenol into catechol, and an easy reaction between catechol and 3(2-aminoethylamino) propyl (dimethoxymethylsilane) (AEAPDMMS) to generate Si NPs, we have designed a label-free fluorescence turn-on probe for TYR activity measurement. After optimization of all reaction pa-rameters, the proposed approach could selectively determine TYR activity in the linearity range of 0.08-9 U mL-1 with the limit of detection (LOD) of 0.03 U mL-1. The practicability of the method in real sample was assessed by measuring TYR activity in human serum sample with successful results. In addition, Si NPs were wonderfully acceptable for Hela and SiHa cells imaging by virtue of their tolerable cytotoxicity and impressive biocompatibility. Therefore, the designed fluorescent biosensor exhibited a potential and widespread imple-mentation in clinical diagnoses assays.

Automated summary

The evolution of fluorometric sensing methods has provided a new opportunity for determining enzymatic activities. We have developed a fluorescent sensing approach using silicon nanoparticles that can accurately measure tyrosinase (TYR) activity. This label-free fluorescence turn-on probe showed a selective determination range of TYR activity and was successfully applied to measure TYR activity in human serum samples. Moreover, the biocompatibility and low cytotoxicity of silicon nanoparticles made them suitable for cell imaging applications.