Download or read book Sum Frequency Generation Vibrational Spectroscopy Studies on Model Peptide Adsorption at the Hydrophobic Solid water and Hydrophilic Solid water Interfaces written by Roger Louis York and published by . This book was released on 2007 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sum Frequency Generation Vibrational Spectroscopy Studies on ModelPeptide Adsorption at the Hydrophobic Solid Water and HydrophilicSolid Water Interfaces written by and published by . This book was released on 2007 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sum frequency generation (SFG) vibrational spectroscopy has been used to study the interfacial structure of several polypeptides and amino acids adsorbed to hydrophobic and hydrophilic surfaces under a variety of experimental conditions. Peptide sequence, peptide chain length, peptide hydrophobicity, peptide side-chain type, surface hydrophobicity, and solution ionic strength all affect an adsorbed peptide's interfacial structure. Herein, it is demonstrated that with the choice of simple, model peptides and amino acids, surface specific SFG vibrational spectroscopy can be a powerful tool to elucidate the interfacial structure of these adsorbates. Herein, four experiments are described. In one, a series of isosequential amphiphilic peptides are synthesized and studied when adsorbed to both hydrophobic and hydrophilic surfaces. On hydrophobic surfaces of deuterated polystyrene, it was determined that the hydrophobic part of the peptide is ordered at the solid-liquid interface, while the hydrophilic part of the peptide appears to have a random orientation at this interface. On a hydrophilic surface of silica, it was determined that an ordered peptide was only observed if a peptide had stable secondary structure in solution. In another experiment, the interfacial structure of a model amphiphilic peptide was studied as a function of the ionic strength of the solution, a parameter that could change the peptide's secondary structure in solution. It was determined that on a hydrophobic surface, the peptide's interfacial structure was independent of its structure in solution. This was in contrast to the adsorbed structure on a hydrophilic surface, where the peptide's interfacial structure showed a strong dependence on its solution secondary structure. In a third experiment, the SFG spectra of lysine and proline amino acids on both hydrophobic and hydrophilic surfaces were obtained by using a different experimental geometry that increases the SFG signal. Upon comparison of these spectra to the SFG spectra of interfacial polylysine and polyproline it was determined that the interfacial structure of a peptide is strongly dependent on its chain length. Lastly, SFG spectroscopy has been extended to the Amide I vibrational mode of a peptide (which is sensitive to peptide secondary structure) by building a new optical parametric amplifier based on lithium thioindate. Evidence is presented that suggests that the interfacial secondary structure of a peptide can be perturbed by a surface.

Download or read book Sum Frequency Generation Vibrational Spectroscopy of Adsorbed Amino Acids Peptides and Proteins of Hydrophilic and Hydrophobic Solid Water Interfaces written by and published by . This book was released on 2010 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sum frequency generation (SFG) vibrational spectroscopy was used to investigate the interfacial properties of several amino acids, peptides, and proteins adsorbed at the hydrophilic polystyrene solid-liquid and the hydrophobic silica solid-liquid interfaces. The influence of experimental geometry on the sensitivity and resolution of the SFG vibrational spectroscopy technique was investigated both theoretically and experimentally. SFG was implemented to investigate the adsorption and organization of eight individual amino acids at model hydrophilic and hydrophobic surfaces under physiological conditions. Biointerface studies were conducted using a combination of SFG and quartz crystal microbalance (QCM) comparing the interfacial structure and concentration of two amino acids and their corresponding homopeptides at two model liquid-solid interfaces as a function of their concentration in aqueous solutions. The influence of temperature, concentration, equilibration time, and electrical bias on the extent of adsorption and interfacial structure of biomolecules were explored at the liquid-solid interface via QCM and SFG. QCM was utilized to quantify the biological activity of heparin functionalized surfaces. A novel optical parametric amplifier was developed and utilized in SFG experiments to investigate the secondary structure of an adsorbed model peptide at the solid-liquid interface.

Download or read book Sum Frequency Generation Vibrational Spectroscopy of Adsorbed Amino Acids Peptides and Proteins at Hydrophilic and Hydrophobic Solid Water Interfaces written by George J. Holinga and published by . This book was released on 2010 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sum frequency generation (SFG) vibrational spectroscopy was used to investigate the interfacial properties of several amino acids, peptides, and proteins adsorbed at the hydrophilic polystyrene solid-liquid and the hydrophobic silica solid-liquid interfaces. The influence of experimental geometry on the sensitivity and resolution of the SFG vibrational spectroscopy technique was investigated both theoretically and experimentally. SFG was implemented to investigate the adsorption and organization of eight individual amino acids at model hydrophilic and hydrophobic surfaces under physiological conditions. Biointerface studies were conducted using a combination of SFG and quartz crystal microbalance (QCM) comparing the interfacial structure and concentration of two amino acids and their corresponding homopeptides at two model liquid-solid interfaces as a function of their concentration in aqueous solutions. The influence of temperature, concentration, equilibration time, and electrical bias on the extent of adsorption and interfacial structure of biomolecules were explored at the liquid-solid interface via QCM and SFG. QCM was utilized to quantify the biological activity of heparin functionalized surfaces. A novel optical parametric amplifier was developed and utilized in SFG experiments to investigate the secondary structure of an adsorbed model peptide at the solid-liquid interface.

Download or read book Studies of Water and Solvents at Liquid solid Interfaces by Sum Frequency Generation Vibrational Spectroscopy written by Zheng Yang and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Vibrational Spectroscopic Studies of Molecular Interaction and Charging Behavior at Solid liquid Interfaces written by Luning Zhang and published by . This book was released on 2008 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibrational Spectroscopy of Water Interfaces written by and published by . This book was released on 1994 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful and versatile tools for studying all kinds of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the second order nonlinear susceptibility. The technique of infrared-visible sum frequency generation (SFG) is particularly attractive because it offers a viable way to do vibrational spectroscopy on any surfaces accessible to light with submonolayer sensitivity. In this thesis, the author applies SFG to study a number of important water interfaces. At the air/water interface, hydrophobic solid/water and liquid/water interfaces, it was found that approximately 25% of surface water molecules have one of their hydrogen pointing away from the liquid water. The large number of unsatisfied hydrogen bonds contributes significantly to the large interfacial energy of the hydrophobic surfaces. At the hydrophilic fused quartz/water interface and a fatty acid monolayer covered water surface, the structure and orientation of surface water molecules are controlled by the hydrogen bonding of water molecules with the surface OH groups and the electrostatic interaction with the surface field from the ionization of surface groups. A change of pH value in the bulk water can significantly change the relative importance of the two interactions and cause a drastic change in orientation of the surface water molecules. SFG has also been applied to study the tribological response of some model lubricant films. Monolayers of Langmuir-Blodgett films were found to disorder orientationaly under mildly high pressure and recover promptly upon removal of the applied pressure.

Download or read book Studies of Charged Molecules at the Air water Interface by Sum Frequency Generation Vibrational Spectroscopy written by Dan Hu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibrational Spectroscopy of Competitive Adsorption at a Liquid Solid Interface Using IR Visible Sum Frequency Generation written by J. Miragliotta and published by . This book was released on 1992 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical IR-Visible sum-frequency generation (SFG), a surface vibrational spectroscopy, has been used to study competitive adsorption at a hydroxylated ZrO2 surface in contact with a number of binary solutions. This technique is similar to surface second harmonic generation (SHG) in that it is forbidden (in the dipole approximation) in spatial regions possessing inversion symmetry. Therefore, systems consisting of an interface bound by centrosymmetric media give rise to a nonlinear response which is dominated by that of the interfacial region. In addition to being surface specific, the SFG signal from the liquid/solid interface can be resonantly enhanced when the incident IR laser source used in the generation process is tuned through a vibrational mode in the adsorbed species, provided the mode is both Raman and IR active. This vibrational information allows identification of the adsorbed molecule as well as measurements of surface coverage, molecular orientation, and adsorbate interactions for a number of the two-component liquid systems.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sum frequency Spectroscopy of Monolayers Adsorbed on Hydrophobic and Hydrophilic Solid Substrates written by A. M. Briggs and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibrational Spectroscopy of Water Interfaces written by Quan Du and published by . This book was released on 1994 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Macroscopic Model for Apparent Protein Adsorption Equillibrium at Hydrophobic Solid water Interfaces written by Kamal Issa Masoud Al-Malah and published by . This book was released on 1993 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sum Frequency Generation SFG Surface Vibrational Spectroscopy and Atomi Force Microscopy AFM Studies of the Composition Structure and Mechanical Behavior of Polymers at Interfaces written by Aric Martin Opdahl and published by . This book was released on 2003 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrafast Vibrational Spectroscopy and Dynamics of Water at Interfaces written by Ali Eftekharibafrooei and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemistry

Download or read book In Situ Adsorption Studies at the Solid Liquid Interface written by D. C. Phillips and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and quartz crystal microbalance (QCM) have been used to study the molecular surface structure, surface topography and mechanical properties, and quantitative adsorbed amount of biological molecules at the solid-liquid interface. The molecular-level behavior of designed peptides adsorbed on hydrophobic polystyrene and hydrophilic silica substrates has been examined as a model of protein adsorption on polymeric biomaterial surfaces. Proteins are such large and complex molecules that it is difficult to identify the features in their structure that lead to adsorption and interaction with solid surfaces. Designed peptides which possess secondary structure provide simple model systems for understanding protein adsorption. Depending on the amino acid sequence of a peptide, different secondary structures ({alpha}-helix and {beta}-sheet) can be induced at apolar (air/liquid or air/solid) interfaces. Having a well-defined secondary structure allows experiments to be carried out under controlled conditions, where it is possible to investigate the affects of peptide amino acid sequence and chain length, concentration, buffering effects, etc. on adsorbed peptide structure. The experiments presented in this dissertation demonstrate that SFG vibrational spectroscopy can be used to directly probe the interaction of adsorbing biomolecules with a surface or interface. The use of well designed model systems aided in isolation of the SFG signal of the adsorbing species, and showed that surface functional groups of the substrate are sensitive to surface adsorbates. The complementary techniques of AFM and QCM allowed for deconvolution of the effects of surface topography and coverage from the observed SFG spectra. Initial studies of biologically relevant surfaces are also presented: SFG spectroscopy was used to study the surface composition of common soil bacteria for use in bioremediation of nuclear waste.

Download or read book A Theoretical Description of the Vibrational Sum Frequency Generation Spectroscopy of Interfaces written by Angela S. Perry and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Our work investigates theoretical approximations to the interface specific sum frequency generation (SFG) spectra at aqueous interfaces constructed using time correlation function (TCF) and instantaneous normal mode (INM) methods. Both approaches lead to signals in excellent agreement with experimental measurements. This work demonstrates how TCF and INM methods can be used in a complementary fashion to describe interfacial vibrational spectroscopy. Our approach is to compare TCF spectra with experiment to establish that our molecular dynamics (MD) methods can reliably describe the system of interest. We then employ INM methods to analyze the molecular and dynamical basis for the observed spectroscopy. We have been able to elucidate, on a molecularly detailed basis, a number of interfacial line shapes, most notably the origin of the complex O-H stretching SFG signal, and the identity of several intermolecular modes in the SFG spectra for the water/vapor interface.