Browsing by Author "Gryczynski, I"

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    Effect of temperature during assembly on the structure and mechanical properties of peptide-based materials.
    (American Chemical Society, 2010-06-01) Ramachandran, S; Taraban, MB; Trewhella, J; Gryczynski, I; Gryczynski, Z; Yu, YB
    Mutually complementary, self-repulsive oligopeptide pairs were designed to coassemble into viscoelastic hydrogels. Peptide engineering was combined with biophysical techniques to investigate the effects of temperature on the structural and mechanical properties of the resulting hydrogels. Biophysical characterizations, including dynamic rheometry, small-angle X-ray scattering (SAXS), and fluorescence spectroscopy, were used to investigate hydrogelation at the bulk, fiber, and molecular levels, respectively. It has been found that temperature has a significant effect on the structure and mechanical properties of peptide-based biomaterials. Oligopeptide fibers assembled at 25°C are formed faster and are two times thicker, and the resulting material is mechanically seven times stronger than that assembled at 5°C. © 2010, American Chemical Society
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    Effects of chain length on oligopeptide hydrogelation
    (Royal Society of Chemistry, 2011-03-21) Taraban, MB; Ramachandran, S; Gryczynski, I; Gryczynski, Z; Trewhella, J; Yu, YB
    The co-assembly of mutually complementary, but self-repulsive oligopeptide pairs into viscoelastic hydrogels has been studied. Oligopeptides of 6, 10, and 14 amino acid residues were used to investigate the effects of peptide chain length on the structural and mechanical properties of the resulting hydrogels. Biophysical characterizations, including dynamic rheometry, small-angle X-ray scattering (SAXS) and fluorescence spectroscopy, were used to investigate hydrogelation at the bulk, fiber, and molecular levels, respectively. Upon mixing, the 10-mer peptides and the 14-mer peptides both form hydrogels while the 6-mer peptides do not. SAXS studies point to morphological similarity of the cross-sections of fibers underlying the 10 : 10 and 14 : 14 gels. However, fluorescence spectroscopy data suggest tighter packing of the amino acid side chains in the 10 : 10 fibers. Consistent with this tighter packing, dynamic rheometry data show that the 10 : 10 gel has much higher elastic modulus than the 14 : 14-mer (18 kPa vs. 0.1 kPa). Therefore, from the standpoint of mechanical strength, the optimum peptide chain length for this class of oligopeptide-based hydrogels is around 10 amino acid residues. © 2010, Royal Society of Chemistry.