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.

► The tyrosinase-chitosan- CNi modified GCE had been constructed.
► Obviously electrochemical response of catechol at modified electrode was obtained.
► A satisfactory stability and bioactivity were obtained for the immobilized enzyme.
► It showed wide liner concentration range and low detection limit.