Molecularly imprinted electrochemical sensor based on poly (o-phenylenediamine-co-o-aminophenol) incorporated with poly (styrenesulfonate) doped poly(3,4-ethylenedioxythiophene) ferrocene composite modified screen-printed carbon electrode for highly sensitive and selective detection of prostate cancer biomarker

A molecularly imprinted polymer (MIP) of o-phenylenediamine (o-PD) and o-aminophenol (o-AP), electropolymerized in the presence of prostate specific antigen (PSA), was deposited on a screen-printed carbon electrode (SPCE) modified with a poly(styrenesulfonate) doped poly(3,4-ethylenedioxythiophene) ferrocene composite (PEDOT:PSS@Fc) to create a MIP/PEDOT:PSS@Fc/SPCE electrochemical sensor. The MIP layer was characterized by scanning electron microscopy (SEM). PSA was determined using differential pulse voltammetry by measuring the change in the oxidation peak current of Fc. At the optimal monomer molar ratio, electro-polymerization condition, phosphate buffer pH and rebinding time, the MIP sensor produced a linear response over a concentration range of 1.0 x 10(-7)-1.0 x 10(-4) ng mL(-1) PSA. The detection limit was (8.3 +/- 1.3) x 10(-8) ng mL(-1) and selectivity, reproducibility, reusability over 12 cycles and long-term stability over 7 weeks were good. Using the Langmuir adsorption isotherm, the dissociation constant (K-D) of the MIP sensor was 1.91 x 10(-6) ng mL(-1). PSA levels detected in blood serum with the present sensor were consistent with the data from the electrochemiluminescence immunoassay (P > 0.05).