Tyrosinase Biosensor for Antioxidants Based on Semiconducting Polymer Support

Abstract

AbstractThis study reports sensitive phenolic compounds detection using biosensing electrode constructed by immobilization of tyrosinase in an electrochemically synthesized copolymer based on N‐nonylcarbazole derivatives on a platinum (Pt) electrode. Tyrosinase has been successfully immobilized (electrolytic deposition) on the surface of thin film built of poly[2,7‐bis(selenophene)‐N‐nonylcarbazole] and poly[3,6‐bis(selenophene)‐N‐nonylcarbazole]. A well‐defined reduction current according to the phenolic compounds was observed in cyclic voltammetry, which assigned to the reduction of biocatalytically produced o‐quinones on the electrode surface. The immersion of the tyrosinase‐equipped electrode in solution with substrate generated large catalytic currents easily recorded by cyclic voltammetry. The response of the biosensing arrangement was estimated in the presence of catechol and L‐3,4‐dihydroxyphenylalanine (L‐DOPA). The system exhibits an explicit catalytic activity and the substrates can be amperometrically determined at +0.07 V vs. Ag/AgCl. The activation energy (Ea) of immobilized tyrosinase catalytic reaction was estimated as 24.65 kJ/mol in PBS buffer. The analytical properties of the developed biosensor, such as linear concentration range, sensitivity, detection limit and reproducibility, repeatibility were also evaluated. Considering the fact, that the immobilization policy proved high efficiency, the results suggest that the method for phenoloxidase immobilization has a big capacity of providing high throughput engineering of bioelectronic devices.