What are some methods for conjugation of antibodies with metallic nanoparticles?

One method of conjugating antibodies with metallic nanoparticles is through passive adsorption, which involves coating the nanoparticle with citrate. At the proper pH and conditions, the antibodies should spontaneously attach to the citrate-coated surface of the nanoparticle.

Antibody and nanoparticle conjugation can also be done by binding functional groups such as amine groups to the surface of the nanoparticle. The covalent bond that forms between the functional groups and antibodies allows for exceptional stability.