title: Mixed adlayer of alkanethiol and peptide on GaAs(100): quantitative characterization by X-ray photoelectron spectroscopy.
abstract: Homogeneous and mixed adlayers composed of an alkanethiol (1-octadecanethiol, ODT) and a peptide (CGISYGRKKRRQRRR) on GaAs(100) were formed in two different solvent systems: phosphate-buffered saline (PBS) and N,N-dimethylformamide (DMF). The chemical composition of each adlayer was characterized by X-ray photoelectron spectroscopy (XPS). The data showed that the makeup of the adlayer and its stability largely depends on the solvent used. Angle-resolved XPS also revealed that the adlayer thickness and tilt angles were different from values obtained from ellipsometry measurements and vastly varied between the two solvents used. The coverage data extracted from the XPS measurements indicated that homogeneous adlayers of peptide in PBS buffer form a multilayered film. Homogeneous alkanethiol adlayers exhibited monolayer coverage under all solvent treatments. Coadsorbed layers containing both alkanethiol and peptide have fractional monolayer coverage in both solvents.
authors.affiliation: Department of Chemistry, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Heeyeon P
authors.initials: HP
authors.lastname: Wampler
authors.forename: Dmitry Y
authors.initials: DY
authors.lastname: Zemlyanov
authors.forename: Kangho
authors.initials: K
authors.lastname: Lee
authors.forename: David B
authors.initials: DB
authors.lastname: Janes
authors.forename: Albena
authors.initials: A
authors.lastname: Ivanisevic
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D001152:Arsenicals / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D012997:Solvents; D013057:Spectrum Analysis; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D014965:X-Rays
chemical_list: D001152:Arsenicals; D010455:Peptides; D012997:Solvents; D013438:Sulfhydryl Compounds; C043055:gallium arsenide; C055360:n-octadecyl mercaptan; D005708:Gallium