Detection of Prostate Specific Antigen Using an Electrochemical Aptamer-Based Biosensor

Detection of the biomarkers is one of the effective methods for diagnosis and treatment of prostate cancer. Prostate specific antigen (PSA) is currently the best biomarker available for controlling and detecting this cancer. The purpose of the current study was to design an electrochemical aptamer-based biosensor (electrochemical aptasensor) to measure the PSA.
In this laboratory study, multi-walled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs), reduced graphene oxide (rGO), and chitosan (CS) were used to increase the electrical conductivity and surface area. The PSA-specific aptamer was also used for binding PSA on the surface of the electrode. Differential pulse voltammetry (DPV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques were applied to study the electrochemical properties and importance of synthesized nanocomposite. This aptasensor was used to measure PSA in four blood samples in patients with prostate cancer and was compared with the in vitro immuno-radiometric method. Data were analyzed using independent t-test.
Based on the calibration curve, the detection limit of 6.0 pg mL-1 and the linear range of 0.01-100.00 ng mL-1 were obtained. The repeatability and reproducibility of this aptasensor for PSA with the concentration of 0.9 ng mL-1 were obtained with relative standard deviations (RSD%) of 2.39 and 4.01%, respectively.
The results of the comparisons between the proposed method and the immuno-radiometric method showed the applicability of the aptasensor to measure the real samples. It seem that the biosensor with low limit of detection and wide linear range may be a suitable device for diagnosis of prostate cancer.