Development of immuno-cytosensor on soft tissue cancers

DEVELOPMENT OF IMMUNO-CYTOSENSOR ON SOFT TISSUE CANCERS In this thesis, first of all, La0.25Fe0.75FeO3 nanoparticle was synthesized using the sol-gel method. Nanoparticles (La0.25Fe0.75FeO3), coated polyacrylonitrile nanofibers (PANnf), were prepared by electrospinning on the pencil graphite electrode (PGE) surface. In another step, carcinoembryonic antigen (CEA) was loaded with CEA antibodies (Anti-CEA) as a biomarker receptor. Finally, PGE/PAN+La0.25Fe0.75FeO3/Anti-CEA was used for CEA detection. The fabrication steps were characterized by cyclic voltammetry and electrochemical impedance spectroscopy in the presence of a [Fe(CN)6]3−/4− probe. Optimization steps and cell studies were performed using differential pulse voltammetry (DPV). The use of this composite system is a novel immunosensor development approach for label-free detection of CEA. Under optimum conditions, detection limit (LOD) of PGE/PAN+La0.25Fe0.75FeO3/Anti-CEA immunosensor LOD (3 s/m) = 1,48 ng/mL, limit of quantification (10s/m ) = 4,94 ng/mL, reproducibility 1,46% (n=5) and R2=0.9984 for antigen concentration within a linear working range of 0,1-10 ng/mL. The results showed that even very small changes in CEA concentration could be detected with the presented system. Also, immunosensor recovery in real serum samples containing dopamine and ascorbic acid was found as 98,94 ± 7,43. It has great potential in clinical screening of different cancer biomarkers. As cytosensor, after 48 hours of incubation, the binding of RT-4, MDA-MB-231, T98G and MCF-7 cells to PGE/PAN, PGE/ PAN/La0.25Fe0.75FeO3 modified and antibody/antigen coated (PGE/PAN/La0.25Fe0.75 FeO3/Anti-CEA/BSA/CEA) surfaces was evaluated by correlating the decrease in current with the amount of cancer cells. Keywords: Immuno-cytosensor, Carcinoembryonic Antigen (CEA), Nanoparticle, Pencil Graphite Electrode, PAN nanofiber, Cancer cell