title: A Thermodynamic Description of the Adsorption of Simple Water-Soluble Peptoids to Silica.
abstract: The first report of a water-soluble peptoid adsorbed to silica monitored by second harmonic generation (SHG) at the liquid/solid interface is presented here. The molecular insights gained from these studies will inform the design and preparation of novel peptoid coatings. Simple 6- and 15-residue peptoids were dissolved in phosphate buffered saline and adsorbed to bare silica surfaces. Equilibrium binding constants and relative surface concentrations of adsorbed peptoids were determined from fits to the Langmuir model. Complementary fluorescence spectroscopy studies were used to quantify the maximum surface excess. Binding constants, determined here by SHG, were comparable to those previously reported for cationic proteins and small molecules. Enthalpies and free energies of adsorption were determined to elucidate thermodynamic driving forces. Circular dichroism spectra confirm that minimal conformational changes occur when peptoids are adsorbed to silica while pH studies indicate that electrostatic interactions impact adsorption.
authors.affiliation: Department of Chemistry and Biochemistry, Santa Clara University , 500 El Camino Real, Santa Clara, California 95053, United States.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Calkins
authors.affiliation: Department of Chemistry and Biochemistry, Santa Clara University , 500 El Camino Real, Santa Clara, California 95053, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Yin
authors.affiliation: Department of Chemistry and Biochemistry, Santa Clara University , 500 El Camino Real, Santa Clara, California 95053, United States.
authors.forename: Jacenda L
authors.initials: JL
authors.lastname: Rangel
authors.affiliation: Department of Chemistry and Biochemistry, Santa Clara University , 500 El Camino Real, Santa Clara, California 95053, United States.
authors.forename: Madeleine R
authors.initials: MR
authors.lastname: Landry
authors.affiliation: Department of Chemistry and Biochemistry, Santa Clara University , 500 El Camino Real, Santa Clara, California 95053, United States.
authors.forename: Amelia A
authors.initials: AA
authors.lastname: Fuller
authors.affiliation: Department of Chemistry and Biochemistry, Santa Clara University , 500 El Camino Real, Santa Clara, California 95053, United States.
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Stokes
mesh_terms: D000327:Adsorption; D002942:Circular Dichroism; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D008968:Molecular Conformation; D009281:Naphthalenes / Q000737:chemistry; D034444:Peptoids / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: C587471:(S)-N-1-(naphthylethyl)glycine; D009281:Naphthalenes; D034444:Peptoids; D011506:Proteins; D014867:Water; C028791:N-(2-aminoethyl)glycine; D012822:Silicon Dioxide; D005998:Glycine