Tyrosinase-functionalized gold nanoparticle-tailored ultrasensitive nanosensing probe for hazardous and nutritional phenolic compounds

Herein, a sensitive, selective, and facile sensing approach was developed by tailoring gold nanoparticles (AuNPs) to detect phenolic compounds in water and food/plant products across a range of concentrations. Sensing probes selective toward four different concentration ranges of phenolic compounds were constructed by varying the capping amounts (µg/mL) of tyrosinase (Ty) on the AuNP surface such as 5, 10, 50, and 100 µg/mL. Accordingly, an ultralow limit of detection (LOD) for phenolic compounds was achieved at 0.01 ppb (along with the upper bound detection of 50,000 ppm) via spectroscopic methodology. Interestingly, the absorbance of the developed sensing probe increased in the presence of phenolic compounds due to separation of Cu (present in Ty) from the proximity of AuNPs. A novel sensing mechanism has been proposed in light of interaction between enzyme substrate and copper of Ty with gold nanoparticles. Moreover, the applicability of the developed sensing probe is successfully validated using the tea leaves samples. •Ty-AuNPs probes were developed for ultrasensitive sensing of phenolic compounds.•The spectroscopic and color-based sensing was performed.•The sensor works well for 0.01 ppb- 50,000 ppm of phenolic compounds.•The lowest LOD value of 0.01 ppb was achieved by Ty-AuNPs (5).•A novel Cu-based sensing mechanism has been proposed.