Damla Kiziltan, Tayfun Vural, Serhat Ozturk, Cem Bayram and Emir Baki Denkbas
Chemistry Department, Hacettepe University, Ankara, Turkey
Determination of cancer biomarkers in blood or urine allows to help to diagnose and treat cancer effectively. Although traditional analysis methods are used in clinic diagnosis effectively novel biosensor technologies has been developed to sense biomolecules faster, simpler, and more economical. One of the most known technics is electrochemical method for determination of biomolecules. Several electrodes are used as working electrode that modified with different modification strategy to enhance signal to noise ratio. Nanotechnology approach for surface modification of electrodes is very innovative that improves sensitivity and selectivity of biosensor. In the study, a novel chitosan-gold nanoparticle (CH-GNP) modified titania electrode was fabricated and used as working electrode in three electrode system for detecting of prostate specific antigen (PSA). Platinum and Ag/AgCl were used as auxiliary and reference electrode respectively. Firstly, optimum anodization parameters were found to fabricate homogenous titania nanotubes on titanium electrodes. Then titania electrodes were modified with chitosan and gold nanoparticles. Imaging of surface of the CH/GNP/Ti electrodes was carried out with scanning electron microscopy and electrochemical characterization was performed by cyclic voltammetry. Anti-PSA (Ab1) was used for modification of CH/GNP/Ti electrodes to generate Ab1/CH/GNP/Ti electrodes. Then PSA and horse radish peroxidase (HRP) conjugated PSA was treated with electrode to fabricate a sandwich electrochemical immunoassay. Quantitative detection of PSA was performed by chronoamperometry and limit of detection was found as 8.0 ng/mL.
Keywords: PSA, electrochemistry, titania, immunosensor.