Homogeneous detection of human IgG by gold nanoparticle probes

A simple, and homogeneous detection system for human IgG based on the optical properties of aggregated gold nanoparticles probes were investigated. When gold nanoparticles with about 13 nm in diameter were modified by goat anti-human IgG, the addition of human IgG could change the absorption of colloidal gold solution, and the absorption intensity at 740 nm depended on the amount of human IgG. The aggregation of gold nanoparticles was also validated using transmission electron microscopy (TEM). A series of experiments were carried out to study the effects of pH value, the reaction temperature, and non-specific adsorption on the assay. A dynamic range of 10–500 μg/3 mL human IgG was observed. The new bioassay could be used for the rapid and homogeneous detection of antibodies in bioanalytical chemistry.