Synthesis of L-phenylalanine stabilized gold nanoparticles and their thermal stability

Here we described the two synthesis methods of L-phenylalanine (L-phe) coated gold nanoparticles through a reduction of aqueous chloroaurate ions directly by L-phe, and also the borohydride reduction of chloroauric acid followed by capping with L-phe molecules. Phenylalanine reduced gold nanoparticles and the phenylalanine capped gold nanoparticles were evaluated by transmission electron microscope and UV-vis spectroscopy, and then their thermal stabilities were compared. We found that the phenylalanine reduced gold nanoparticles were unstable and form linearly arranged aggregates on aging, while as the phenylalanine capped gold nanoparticles were stable for months in ambient condition.