Enzyme-antibody dual-film modified gold nanoparticle probe for ultrasensitive detection of alpha fetoprotein.

In this study, we designed a comprehensive strategy for the ultrasensitive detection of alpha fetoprotein (AFP) with high specificity using gold nanoparticle (AuNP)-based enzyme-linked immunosorbent assay (ELISA). A dual-film modified probe was synthesized by coating AuNPs with horseradish peroxidase (HRP) on its surface. Anti-AFP monoclonal antibody (McAb) was immobilized on the surface of the enzyme using glutaraldehyde cross-linking method. AuNPs, employed as support for the immobilization of HRP. HRP was used not only as the enzymatic-amplified tracer but also as a bridge for loading McAb. The limit of detection was 2 ng mL-1 . The developed probes can provide an alternative approach with high sensitivity and a simple process similar to that of the traditional HRP-McAb based ELISA for the ultrasensitive detection of AFP in serum.