In situ electrodeposition of biocomposite materials by sinusoidal voltages on microelectrodes array for tyrosinase based amperometric biosensor development

Abstract The amperometric detection of dopamine (DA) and catechol (CT) was achieved at tyrosinase (Ty)-poly(3,4-ethylenedioxythiophene) (PEDOT) bio-composite film-modified gold (Au) disc microelectrode arrays. The PEDOT-Ty bio-composite coatings were prepared by electrochemical polymerization of the corresponding monomer 3,4-ethylenedioxythiophene (EDOT) in the presence of various amounts of Ty on Au microelectrode arrays using sinusoidal voltages. The use of sinusoidal voltages in preparing bio-composite coatings is reported here for the first time. The bio-composite coatings deposited on different arrays by sinusoidal voltages and potentiostatic methods were compared. The bio-composite coatings were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), infrared reflection absorption spectroscopy (IRRAS), and atomic force microscopy (AFM). This new preparation procedure provided a simple and reliable enzyme immobilization preserving the enzymatic activity. The amperometric detection of DA and CT was achieved at a working potential of -0.2 V in physiological buffered solutions. Multianalyte detection was achieved connecting different microelectrode arrays to a bipotentiostat. The analytical performance of the biosensor in terms of limit of detection, linear response range, sensitivity, and working stability, were investigated. The microelectrodes array based biosensor obtained by using sinusoidal voltages displayed a linear response for dopamine concentrations ranging from 10 to 150 μM, with a limit of detection (3 Sb / m , where Sb is the standard deviation of the blank and m is the slope of the calibration plot) of 0.99 μM. A linear response for catechol concentrations ranging from 10 to 60 μM and a detection limit of 5.58 μM were also obtained for this micro-biosensor.