Electrochemical detection of prostate specific antigen in the presence of an aptamer and composites of cobalt phthalocyanine-exfoliated graphite

Abstract

This work focuses on the development of biosensor and their use for the detection of prostate specific antigen (PSA). The three cobalt phthalocyanine (CoPc) complexes, exfoliated graphite (EG), and an aptamer are used to make a probe for PSA detection. Each CoPc complex is π-π stacked onto the EG to form EG-CoPc(π-π) hybrid which was then used to modify a glassy carbon electrode (GCE). EG and CoPc were also used to modify the GCE sequential (seq) with CoPc on top to give GCE-EG-CoPc(seq). For the detection PSA, PSA specific aptamer was either adsorbed or covalently linked to the modified electrodes. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were the techniques used for the detection of PSA. The electrodes were found to be selective in the presence of bovine serum albumin, glucose and cysteine and were stable when 50 DPV scans were run. The electrodes showed good % recovery when human serum was spiked with different PSA concentrations.