A catechol biosensor based on a gold nanoparticles encapsulated-dendrimer.

Tyrosinase has been immobilized on a Au nanoparticles encapsulated-dendrimer bonded conducting polymer on a glassy carbon electrode for the estimation of catechol. The modified electrode was characterized by cyclic voltammetry and AFM techniques. The principle of catechol estimation was based on the reduction of biocatalytically liberated quinone species at +0.2 V versus Ag/AgCl (3 M KCl), with good stability, sensitivity, and featuring a low detection limit (about 0.002 μM) and wide linear range (0.005 μM-120 μM). The electrochemical redox peak of catechol on the GCE/PolyPATT/Den(AuNPs)/tyrosinase was also investigated. A response time of 7 s, reusability up to 5 cycles and a shelf life of more than 2 months under refrigerated conditions were reported. Various parameters influencing biosensor performance have been optimized including pH, temperature, and applied potential. The utility and application of this nanobiosensor was tested in a real water samples.