Preparation of Colloidal Gold Particles and Conjugation to Protein A, IgG, F(ab)2, and Streptavidin

Colloidal gold probes, including protein A-, IgG-F(ab’ )2 -, and streptavidin-labeled gold particles, are useful tools for localization of antigens in cells and tissues by immunoelectron microscopy (IEM). This chapter describes different methods for the preparation of colloidal gold and conjugation of colloidal gold to protein A, IgG, and streptavidin.