Immunological detection of hepatocellular carcinoma biomarker GP73 based on dissolved magnetic nanoparticles

The peroxidase-like activity of dissolved Fe3O4 magnetic nanoparticles was reported in this work. The chromogenic results of dissolved magnetic nanoparticles demonstrated almost the same change trend as standard ferric ion solutions. And the chromogenic reactions of dissolved Fe3O4 magnetic nanoparticles were more sensitive than that of whole Fe3O4 magnetic nanoparticles. The chromogenic reaction of dissolved Fe3O4 magnetic nanoparticles was utilized to replace the chromogenic reaction of horseradish peroxidase in traditional enzyme-linked immunosorbent assay and applied in the immunoassay of hepatocellular carcinoma biomarker GP73. The method based on the chromogenic reaction of dissolved Fe3O4 magnetic nanoparticles achieved a detection limit of 250 ng/mL, which was more sensitive than the method based on the peroxidase-like activity of whole Fe3O4 magnetic nanoparticles. The immunological detection method based on dissolved Fe3O4 magnetic nanoparticles proved to be simple, sensitive, specific and low-cost in this paper.