NLISA versus enzyme-linked immunosorbent assay: Nanozyme-linked immunosorbent array based on platinum sub-nanocluster...

Rapid and accurate identification of tumor metabolic markers is important for early tumor diagnosis and individualized treatment. Here, a stable monodisperse sub-nanometer platinum (Pt) material was developed as a highly efficient nanozyme with a specific activity of peroxidase as high as 20.86 U mg^-1 through the growth of in situ domain-limited Pt quantum dots via the polymer polyvinylpyrrolidone. Further, the synthesis of large quantities of Pt-loaded SiO₂ (Pt-SiO₂ ) was determined by silylation reaction and used for naked eye colorimetric testing of human alpha-fetoprotein (AFP). In particular, the immunization incubation process occurred in preprepared microplates. A nanozyme-based immunomodel was constructed in the presence of the target AFP, and a chromogenic reaction occurred with exogenous hydrogen peroxide and the chromogenic substrate tetramethylbenzidine. On optimization of experimental conditions, the dynamic working response range for AFP was found to be 0.05-20 ng mL^-1 , with a limit of detection of 38.7 pg mL^-1 . This work provides a new strategy to design efficient nanozyme-based enzyme-linked immunochromatographic platforms to meet the practical use of replacing natural enzymes.