Conjugating folic acid to gold nanoparticles through glutathione for targeting and detecting cancer cells

Folic acid-functionalized gold nanoparticles were prepared by a three-step approach. The thiol group of glutathione conjugates with gold nanoparticles through Au-S bond. DCC and NHS are used to activate the carboxyl groups of GSH, forming a highly reactive intermediate. The activated carboxyl groups react subsequently with the free amino group presented in folic acid, resulting in the formation of folic acid-conjugated nanoparticles.