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

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 SeO32- and the controlled synthesis of Se NPs for biological and medical applications by bioaffinity adsorption and photoreduction.