Sandwich-type ELISA Impedimetric Immunosensor for Early Detection of Prostate-specific Antigen (PSA) in Human Serum

Early detection of cancer is vital for the successful treatment of the disease. Hence, a rapid and sensitive diagnosis is essential before the cancer is spread out to the other body organs. A gold millielectrode (GME) functionalized with a mixed (16-MHA+EG3SH) self-assembled monolayer (SAM) was used to fabricate a point-of-care immunosensor for the detection of the prostate cancer biomarker: prostate-specific antigen (PSA) in human serum samples. An organic matrix (Amine-PEG3-biotin/Avidin) was used to reduce non-specific protein adsorption on the electrode surface. A 16-MHA/EG3SH/Amine-PEG3-biotin/Avidin GME was exposed to solutions with different sandwich-type immunocomplex (BtnAb-AgPSA-HRPAb) concentrations and its response was measured using the electrochemical impedance spectroscopy (EIS) technique. This approach was compared with regard to a reference ELISA immunoassay. The obtained results showed that the immunosensor proposed in this work qualifies for its pre-clinical application in the quantification of PSA in serum samples of a representative Mexican population.