An Electrochemical Immuno-cytosensor Modified with Nanofibers for the Determination of a Carcinoembryonic Antigen

In this study, La_0.25Fe_0.75FeO₃ (PNp)perovskite nanoparticle was synthesized using the sol–gel method. PNp-coated polyacrylonitrile (PAN) nanofibers 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@PNp/Anti-CEA was used for CEA detection. Optimization steps and cell culture steps 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@PNp/Anti-CEA immunosensor LOD 1.48 ng/mL, limit of quantification (LOQ) = 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. 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. The number of cells attached to the PGE/PAN@PNp/Anti-CEA/BSA(bovine serum)/CEA surface decreased in RT-4(bladder cancer), MDA-MB-231 (triple-negative breast adenocarcinoma cell line), and T98G cells (glioblastoma multiforme cell line), which are known as CEA-negative cell lines, whereas the number of MCF-7 cells (estrogen-sensitive human breast cancer cell line, known to be CEA positive) attached to the PGE/PAN@PNp/Anti-CEA/BSA/CEA surface increased, indicating higher affinity to the immunosensor surface. As a result, while MCF-7, which is CEA positive, can be determined best when using an immune-cytosensor, the cell that can be best determined with cytosensors was found to be RT-4.