Construction of a simple PEC immunosensing platform based on polydopamine and PEDOT sensitized BiWO for sensitive detection of carcinoembryonic antigen.

Organic-inorganic composite photoactive materials can combine the merits of organic and inorganic components and show better performance in comparison with single-component materials. In this work, a novel photoactive material was synthesized through chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) on the surface of hydrothermally prepared BiWO, followed by modification of self-polymerized dopamine (PDA). The integration of poly(3,4-ethylenedioxythiophene) (PEDOT) and BiWO effectively facilitated the separation of photogenerated electron-hole pairs, thus demonstrated substantially strong photoelectrochemical signal compared to pure BiWO. The PDA film, with abundant functional groups, could further sensitize the material and facilitate the immobilization of recognition units. As a proof of application, the composite was combined with carcinoembryonic antibody to construct an immunosensor for carcinoembryonic antigen sensing. Resultantly, although the components and construction procedure were simple, the prepared sensor demonstrated a broad linear detection range of 0.001-20 ng/mL and a relative low detection limit of 0.50 pg/mL. It also showed high selectivity and stability. Its practical feasibility was confirmed by detecting real samples and yielding satisfactory results.