title: Covalent attachment of TAT peptides and thiolated alkyl molecules on GaAs surfaces.
abstract: Four TAT peptide fragments were used to functionalize GaAs surfaces by adsorption from solution. In addition, two well-studied alkylthiols, mercaptohexadecanoic acid (MHA) and 1-octadecanethiol (ODT) were utilized as references to understand the structure of the TAT peptide monolayer on GaAs. The different sequences of TAT peptides were employed in recognition experiments where a synthetic RNA sequence was tested to verify the specific interaction with the TAT peptide. The modified GaAs surfaces were characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS). AFM studies were used to compare the surface roughness before and after functionalization. XPS allowed us to characterize the chemical composition of the GaAs surface and conclude that the monolayers composed of different sequences of peptides have similar surface chemistries. Finally, FT-IRRAS experiments enabled us to deduce that the TAT peptide monolayers have a fairly ordered and densely packed alkyl chain structure. The recognition experiments showed preferred interaction of the RNA sequence toward peptides with high arginine content.
authors.affiliation: Department of Chemistry and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Youngnam
authors.initials: Y
authors.lastname: Cho
authors.forename: Albena
authors.initials: A
authors.lastname: Ivanisevic
mesh_terms: D001120:Arginine / Q000737:chemistry; D001152:Arsenicals / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry*; D015696:Gene Products, tat / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010169:Palmitic Acids / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D012313:RNA / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D014965:X-Rays
chemical_list: C450319:16-mercaptohexadecanoic acid; D001152:Arsenicals; D015696:Gene Products, tat; D010169:Palmitic Acids; D010446:Peptide Fragments; D013438:Sulfhydryl Compounds; C043055:gallium arsenide; C055360:n-octadecyl mercaptan; D012313:RNA; D001120:Arginine; D005708:Gallium