The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Alexei V Tivanski - One of the best experts on this subject based on the ideXlab platform.

Laura A. Delia - One of the best experts on this subject based on the ideXlab platform.

  • Impedance Characterization of a Quartz Crystal Microbalance
    Electroanalysis, 2006
    Co-Authors: Petr Vanýsek, Laura A. Delia
    Abstract:

    The impedance characteristics of the quartz crystal used in quartz crystal microbalance is considered a higher dimension of information that can be obtained in addition to the resonant frequency change of the crystal. The impedance allows calculating the quality factor of the oscillator that is very closely related to the Mechanical Rigidity of the material, which is adsorbed or deposited on the quartz crystal. This paper concentrates on utilizing an impedance analyzer, often found in electroanalytical laboratories, instead of the usually required network analyzer.

Joel P. Schneider - One of the best experts on this subject based on the ideXlab platform.

  • Utilizing Frémy's Salt to Increase the Mechanical Rigidity of Supramolecular Peptide-Based Gel Networks.
    Frontiers in bioengineering and biotechnology, 2021
    Co-Authors: Galit Fichman, Joel P. Schneider
    Abstract:

    Peptide-based supramolecular gels are an important class of biomaterials that can be used for biomedical applications ranging from drug delivery to tissue engineering. Methodology that allows one to readily modulate the Mechanical properties of these gels will allow yet even a broader range of applications. Fremy's salt is an inorganic salt and long-lived free radical that is known to oxidize phenols. Herein, we show that Fremy's salt can be used to dramatically increase the Mechanical Rigidity of hydrogels formed by tyrosine-containing self-assembling β-hairpin peptides. When Fremy's salt is added to pre-formed gels, it converts tyrosine residues to o-quinones that can subsequently react with amines present within the lysine side chains of the assembled peptide. This results in the installation of chemical crosslinks that reinforce the gel matrix. We characterized the unoxidized and oxidized gel systems using UV-Vis, transmission electron microscopy and rheological measurements and show that Fremy's salt increases the gel Rigidity by nearly one order of magnitude, while retaining the gel's shear-thin/recovery behavior. Thus, Fremy's salt represents an on-demand method to modulate the Mechanical Rigidity of peptide-based self-assembled gels.

  • Enhanced Mechanical Rigidity of Hydrogels Formed From Enantiomeric Peptide Assemblies
    Journal of the American Chemical Society, 2011
    Co-Authors: Katelyn J. Nagy, Michael C. Giano, Albert J. Jin, Darrin J. Pochan, Joel P. Schneider
    Abstract:

    Chirality can be used as a design tool to control the Mechanical Rigidity of hydrogels formed from self-assembling peptides. Hydrogels prepared from enantiomeric mixtures of self-assembling β-hairpins show nonadditive, synergistic, enhancement in material Rigidity compared to gels prepared from either pure enantiomer, with the racemic hydrogel showing the greatest effect. CD spectroscopy, TEM, and AFM indicate that this enhancement is defined by nanoscale interactions between enantiomers in the self-assembled state.

  • De Novo Design of a Shear-Thin Recoverable Peptide-Based Hydrogel Capable of Intrafibrillar Photopolymerization
    Macromolecules, 2010
    Co-Authors: Ronak V. Rughani, Darrin J. Pochan, Monica C. Branco, Joel P. Schneider
    Abstract:

    A de novo designed peptide-based gel has been prepared whose Mechanical Rigidity can be modulated after shear-thin recovery. The photopolymerizable β-hairpin peptide named MLD undergoes temperature...

  • "Click" chemistry in a supramolecular environment: stabilization of organogels by copper(I)-catalyzed azide-alkyne [3 + 2] cycloaddition.
    Journal of the American Chemical Society, 2006
    Co-Authors: David Díaz Díaz, Joel P. Schneider, Karthikan Rajagopal, Erica Strable, M. G. Finn
    Abstract:

    Organogels are thermoreversible, viscoelastic (soft) materials consisting of low molecular weight compounds which self-assemble into fibers, often of micrometer lengths and nanometer diameters. The installation of terminal azide and alkyne functional groups on the end of a standard alkylamide-based organogelator was found to cause a modest disruption in the gelation properties of the molecule. Cross-linking of those groups by the copper(I)-catalyzed azide-alkyne cycloaddition reaction produced thermoreversible materials of substantially greater gelation temperatures and Mechanical Rigidity. These results highlight the ability of azides and alkynes-participants in the most commonly used "click" reaction-to function as innocuous precursors to meaningful covalent interactions in materials science.

Al A Tiba - One of the best experts on this subject based on the ideXlab platform.

Petr Vanýsek - One of the best experts on this subject based on the ideXlab platform.

  • Impedance Characterization of a Quartz Crystal Microbalance
    Electroanalysis, 2006
    Co-Authors: Petr Vanýsek, Laura A. Delia
    Abstract:

    The impedance characteristics of the quartz crystal used in quartz crystal microbalance is considered a higher dimension of information that can be obtained in addition to the resonant frequency change of the crystal. The impedance allows calculating the quality factor of the oscillator that is very closely related to the Mechanical Rigidity of the material, which is adsorbed or deposited on the quartz crystal. This paper concentrates on utilizing an impedance analyzer, often found in electroanalytical laboratories, instead of the usually required network analyzer.