A new and selective and sensitive nanogold-labeled immunoresoance scattering spectral assay for trace prealbumin

A gold-labeled immunoresonance scattering spectral probe for trace prealbumin (PA) was prepared by using gold nanoparticles in size of 9.0 nm to label goat anti-human prealbumin polyclonal antibody. The immune reaction between the gold-labeled antibody and prealbumin took place in pH 7.6 Na2HPO4–NaH2PO4 buffer solution. In the presence of polyethylene glycol PEG-10000, the labeled gold nanoparticles were released and aggregated which brought the resonance scattering intensity (IRS) at 580 nm to enhance greatly. The ΔIRS is proportional to the prealbumin concentration in the range from 16.67 to 666.67 ng/mL, with a detection limit of 4.1 ng/mL. This simple, sensitive and selective assay was applied to determination of prealbumin in human plasma, with satisfactory results.