Carbazole-Pyranine-Derived Polymeric Network Integrated Electrochemical Immunosensor for Prostate-Specific Antigen...

Prostate-specific antigen (PSA), which is a significant biomarker of prostate cancer, is quantified for the development of the diagnosis and treatment of prostate cancer. In this study, a new electrochemical immunosensor was fabricated using a hybrid material (CP@MWCNT) composed of multiwalled carbon nanotubes (MWCNT) and carbazole pyranine (CP) polymer. Pyranine was functionalized with 4-(9H-carbazol-9-yl)aniline for polymerization, and amine groups were used to increase antibody immobilization. The resulting pyranine polymer was synthesized via oxidative polymerization in MWCNT media in the presence of an FeCl₃ catalyst. The characterization, thermal stabilities, and surface morphologies of the CP@MWCNT and CP were elucidated using FT-IR, UV-vis spectroscopy, TGA, SEM, and TEM. CP@MWCNT mixed with chitosan was drop-cast onto glassy carbon electrodes. Favorable analytical performance was confirmed by differential pulse voltammetry (DPV), with a broad linear range (0.0001-1 ng/mL) and low LOD (limit of detection) and LOQ (limit of quantification) values of 0.12 pg/mL and 0.36 pg/mL, respectively. The demonstrated immunosensor showed good selectivity against various antigens, along with high reproducibility (RSD of 0.93%) and excellent long-term stability. Moreover, the immunosensor proved suitable for commercial blood serum analysis, with analytical accuracy and reliability validated through recovery studies and comparison with a commercially available ELISA (enzyme-linked immunosorbent assay) kit.