title: Rigidity of poly-L-glutamic acid scaffolds: Influence of secondary and supramolecular structure.
abstract: Poly-l-glutamic acid (PGA) is a widely used biomaterial, with applications ranging from drug delivery and biological glues to food products and as a tissue engineering scaffold. A biodegradable material with flexible conjugation functional groups, tunable secondary structure, and mechanical properties, PGA has potential as a tunable matrix material in mechanobiology. Recent studies in proteins connecting dynamics, nanometer length scale rigidity, and secondary structure suggest a new point of view from which to analyze and develop this promising material. We have characterized the structure, topology, and rigidity properties of PGA prepared with different molecular weights and secondary structures through various techniques including scanning electron microscopy, FTIR, light, and neutron scattering spectroscopy. On the length scale of a few nanometers, rigidity is determined by hydrogen bonding interactions in the presence of neutral species and by electrostatic interactions when the polypeptide is negatively charged. When probed over hundreds of nanometers, the rigidity of these materials is modified by long range intermolecular interactions that are introduced by the supramolecular structure.
authors.affiliation: Oak Ridge National Laboratory, Joint Institute for Neutron Sciences, Oak Ridge, Tennessee, 37831.|Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Nickels
authors.affiliation: Oak Ridge National Laboratory, Joint Institute for Neutron Sciences, Oak Ridge, Tennessee, 37831.|Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996.|Chemical and Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.
authors.forename: Stefania
authors.initials: S
authors.lastname: Perticaroli
authors.affiliation: Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.
authors.forename: Georg
authors.initials: G
authors.lastname: Ehlers
authors.affiliation: Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Feygenson
authors.affiliation: Oak Ridge National Laboratory, Joint Institute for Neutron Sciences, Oak Ridge, Tennessee, 37831.|Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996.|Chemical and Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831.
authors.forename: Alexei P
authors.initials: AP
authors.lastname: Sokolov
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D060833:Cellular Microenvironment; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011099:Polyglutamic Acid / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011099:Polyglutamic Acid
keywords: boson peak; elastic modulus; mechanobiology nanomechanical; neutron and light scattering; tissue engineering