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

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.