title: A permanent change in protein mechanical responses can be produced by thermally-induced microdomain mixing.
abstract: Electrospinning was employed to fabricate 3-D fiber networks from a recombinant amphiphilic elastin-mimetic tri-block protein polymer and the effects of moderate thermal conditioning (60 degrees C, 4 h) on network mechanical responses investigated. Significantly, while cryo-high resolution scanning electron microscopy (cryo-HRSEM) revealed that the macroscopic and microscopic morphology of the network structure was unchanged, solid-state (1)H-NMR spectroscopy demonstrated enhanced interphase mixing of hydrophobic and hydrophilic blocks. Significantly, thermal annealing triggered permanent changes in network swelling behavior (28.75 +/- 2.80 non-annealed vs. 13.55 +/- 1.39 annealed; P < 0.05) and uniaxial mechanical responses, including Young's modulus (0.170 +/- 0.010 MPa non-annealed vs. 0.366 +/- 0.05 MPa annealed; P < 0.05) and ultimate tensile strength (0.079 +/- 0.008 MPa vs. 0.119 +/- 0.015 MPa; P < 0.05). To our knowledge, these investigations are the first to note that mechanical responses of protein polymers can be permanently altered through a temperature-induced change in microphase mixing.
authors.affiliation: Department of Surgery, Emory University, Atlanta, 101 Woodruff Circle, GA 30332, USA.
authors.forename: Rory E
authors.initials: RE
authors.lastname: Sallach
authors.forename: Johannes
authors.initials: J
authors.lastname: Leisen
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Caves
authors.forename: Emily
authors.initials: E
authors.lastname: Fotovich
authors.forename: Robert P
authors.initials: RP
authors.lastname: Apkarian
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Conticello
authors.forename: Elliot L
authors.initials: EL
authors.lastname: Chaikof
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D004549:Elastin / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D011506:Proteins; D011994:Recombinant Proteins; D004549:Elastin