A novel tyrosinase biosensor based on chitosan-carbon-coated nickel nanocomposite film.

A novel nanocomposite film of tyrosinase-chitosan-carbon-coated nickel nanoparticles (CNi) had been constructed for the detection of catechol. The tyrosinase-chitosan-CNi bionanocomposite film was characterized with scanning electron microscopic (SEM) and electrochemical impedance spectroscopy (EIS). In pH 6.5 phosphate buffer solutions (PBS), the biosensor was applied to detect catechol with a broad linear range from 0.25 nM to 27 μM, the detection limit was brought down to 0.083 nM (S/N=3). The proposed biosensor demonstrated rapid response, as well as good reproducibility and stability. The chitosan-CNi film was propitious to the immobilization of tyrosinase and to the retention of its bioactivity to a large extent. Therefore, the film has potential applications in the immobilization of other enzyme-based biosensors.