Prostate cancer is the most common cancer in men in Europe and Slovenia and the third cause of cancer death. The detection of biomarkers, such as prostate-specific antigen, allows early detection of the disease and thus increases patients’ chances of survival. In this work, an immunosensor for the electrochemical impedance spectroscopic detection of PSA was developed. The immunosensor is based on nanosized graphene sheets, decorated with titanium oxynitride nanoparticles and ruthenium catalysts. The material was silanized using (3-aminopropyl)triethoxysilane and the subsequent modification layers included glutaraldehyde, protein A, anti-PSA antibodies and bovine serum albumin. Each modification layer served a specific purpose, with the main goal of effective immobilization of the antibodies, followed by sensitive and selective detection of PSA. Deposition of immunosensor’s layers was conducted along with studying the effect of fabrication steps and selected operational parameters. The PSA detection was confirmed via negative control and linear response of the immunosensor toward antigen in the clinically relevant concentration range was demonstrated.
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