Facile construction of poly (indole‑5‑carboxylic acid) @ poly (3, 4‑ethylenedioxythiophene) label-free immunosensing platform for sensitive detection of prostate specific antigen.

Abstract In this paper, core-shell structured poly (indole‑5‑carboxylic acid) @ poly (3, 4‑ethylenedioxythiophene) (PIn‑5‑COOH@PEDOT) composite was prepared by a facile two-step chemical oxidation method. The composite possesses large specific surface area, high stability, good electrical conductivity and redox activity, which was designed as label-free electrochemical immunosensing platform for the monitor of the prostate specific antigen (PSA). In this sensing system, PIn-5-COOH served as both signal molecule and antibody carrier. The coating PEDOT was used to enhance the conductivity and stability of PIn-5-COOH. Benefiting from the synergistic effects between PIn-5-COOH and PEDOT, the fabricated immunosensor exhibited a wide linear range of 0.01–25 ng mL−1 and low detection limit of 3.4 pg mL−1 (S/N = 3) for the assay of PSA, coupled with good selectivity, reproducibility and stability. The immunosensor is simple, sensitive, specific and reproducible, which could provide a potential approach for clinical diagnosis. Graphical abstract A sensitive label-free immunosensor for PSA was developed based on core-shell structure PIn-5-COOH@PEDOT nanocomposite. Unlabelled Image Highlights • Core-shell structured PIn-5-COOH@PEDOT composite was prepared. • A sensitive label-free immunosensor for PSA was constructed using PIn-5-COOH@PEDOT. • PIn-5-COOH served as both signal molecule and antibody carrier. • The immunosensor showed wide detection range and low detection limit. • The immunosensor can be utilized as a simple tool to detect PSA in real sample. [ABSTRACT FROM AUTHOR]