title: Spectroscopic analysis of L-histidine adsorbed on gold and silver nanoparticle surfaces investigated by surface-enhanced Raman scattering.
abstract: The adsorption of l-histidine on gold (Au) and silver (Ag) nanoparticle surfaces has been comparatively analyzed by means of surface-enhanced Raman scattering (SERS). The SERS spectra of l-histidine on Ag were found to be quite different from those on Au, indicating dissimilar adsorption structures depending on metal substrates. Most peaks of l-histidine on Ag appeared to be due to coordination via the carboxylate (COO(-)) group with an imidazole ring of fairly upright geometry, whereas on Au it was assumed to adsorb with a rather flat geometry. A density functional theory (DFT) calculation was performed at the level of B3LYP/LANL2DZ to estimate the energetic stability of the binding of the imidazole ring and the carboxylate group of l-histidine with the Ag and Au atoms, respectively. Based on the DFT calculation, the carboxylate group of l-histidine was predicted to bind more favorably to Ag than to Au, and this was in line with our SERS spectral analysis.
authors.affiliation: Department of Chemistry, Soongsil University, Seoul 156-743, Republic of Korea.
authors.forename: Jong Kuk
authors.initials: JK
authors.lastname: Lim
authors.forename: Youngmin
authors.initials: Y
authors.lastname: Kim
authors.forename: So Yeong
authors.initials: SY
authors.lastname: Lee
authors.forename: Sang-Woo
authors.initials: SW
authors.lastname: Joo
mesh_terms: D000327:Adsorption; D006046:Gold / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014732:Vibration
chemical_list: D012834:Silver; D006639:Histidine; D006046:Gold