Mixed adlayer of alkanethiol and peptide on GaAs(100): quantitative characterization by X-ray photoelectron spectroscopy.
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.
Wampler
Heeyeon P
HP
Department of Chemistry, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
Zemlyanov
Dmitry Y
DY
Lee
Kangho
K
Janes
David B
DB
Ivanisevic
Albena
A
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
D001152:Arsenicals; D010455:Peptides; D012997:Solvents; D013438:Sulfhydryl Compounds; C043055:gallium arsenide; C055360:n-octadecyl mercaptan; D005708:Gallium