Structural and impedance spectroscopic studies on biofunctionalized poly(pyrrole-co-pyrrolepropylic acid) film

We report structural and ac impedimetric properties of a biofunctionalized copolymer poly(pyrrole-co-pyrrolepropylic acid) (PPy-PPa) film electrochemically grown onto an indium-tin-oxide (ITO) coated glass plate. The copolymer film was bio-functionalized with myoglobin protein antibody, Ab-cMb, to form a bioelectrode. The bioelectrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), contact angle measurement and electrochemical techniques. The ac impedance studies of the PPy-PPa copolymer film show both charge transfer resistance (Ret) and ions diffusion (WR) characteristics, at high and low frequency regions respectively, whereas the biofunctionalized electrode shows only Ret in a comparatively low ac frequency region with respect to the PPy-PPa film, indicating a good biocompatibility of the polymer electrode. The ac impedimetric performance of the bioelectrode was studied toward the detection of myoglobin protein antigen, Ag-cMb, in a phosphate buffer solution. The bioelectrode exhibited a linear impedance response to Ag-cMb concentration in the range 10 ng to 1 μg mL−1.