Self-assembled selenium nanoparticles and their application in the rapid diagnostic detection of small cell lung...

By coupling molecular imprinting, chitosan biosorption and TiO₂ photocatalysis, selenium nanoparticles (Se NPs) were self-assembled in a controlled manner on the molecular imprinting sites of zeolite-chitosan-TiO₂ microspheres. Se NPs with different sizes and areal densities were individually synthesized by controlling the rapid adsorption of molecular-imprinted nanocomposites and photocatalytic reaction of TiO₂ nanoparticles. In order to improve the sensitivity and specificity of rapid diagnostic detection, Se NPs were self-assembled again into high-order and spherically stable structures with an average size of 80 nm by well-defined monomer units, after separation from zeolite-chitosan-TiO₂ microspheres with a stabilizer of 0.3% (v/v) bovine serum albumin. Due to their biological activity, spherical-shaped Se NPs were used for dot-blot immunoassays with multiple native antigens for rapid serodiagnosis of human lung cancer. The sensitivity of the dot immunoassays for detecting progastrin-releasing peptide (ProGRP) was 75 pg mL^-1. The detection time of colloidal Se dot immunoassays for ProGRP was only 5 min. No positive results were observed with other commonly potential interfering substances, including carcinoembryonic antigen, α-fetoprotein antigen and BSA. The research presents a simple and green method for the reuse of SeO₃^2- and the controlled synthesis of Se NPs for biological and medical applications by bioaffinity adsorption and photoreduction.