Immobilization of cytochrome c and its application as electrochemical biosensors

چکیده مقاله

A modified electrode PAN/PPY/cMWCNTs composed of polyaniline/polypyrrole (PAN/PPY) bilayer conducting polymer film,
carboxylated multi-walled carbon nanotubes (cMWCNTs), and glassy carbon electrode (GCE) was fabricated and examined for
their potential applicability in the third-generation amperometric biosensor. Cytochrome c (Cyt c) was immobilized on the surface
of modified PAN/PPY/cMWCNTs/GCE and its chemical and electrochemical properties were investigated by Fourier transform
infrared spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry techniques. The modified
Cyt c/PAN/PPY/cMWCNTs/GCE exhibited well-defined redox peaks with the formal potential and peak-to-peak separation -
0.338 V and 0.068 V (vs. Ag/AgCl, 3 M KCl), respectively. The surface coverage concentration of Cyt c was estimated to be
8.0 × 10−9 mol cm−2. The application of the prepared Cyt c/PAN/PPY/cMWCNTs/GCE for detection of hydrogen peroxide
(H2O2) showed a sensitivity of 101.6 μA mM−1 with a detection limit of 0.1 μM in a linear response range of 1 to 370 μM.
According to the obtained results, the proposed PAN/PPY/cMWCNTs nanocomposite could act as a charge promoter to facilitate
direct electron transfer between immobilized Cyt c and GCE, offering a high potential for application in third-generation
amperometric biosensors.