(1)H MAS NMR study of cysteine-coated gold nanoparticles.

(1)H MAS NMR experiments were performed on gold nanoparticles coated with l-cysteine. The experiments show that l-cysteine molecules are zwitterions and support a structural model of cysteine forming two layers. The inner layer is composed of cysteine molecules chemisorbed to the gold surface via the sulfur atom. The outer layer interacts with the chemisorbed layer. The (1)H NMR suggests that the cysteine in the outer layer exhibits large amplitude motion about specific carbon-carbon bonds.