Wet-Spinning of Recombinant Silk-Elastin-Like Protein Polymer Fibers with High Tensile Strength and High Deformability

Abstract

A recombinant silk-elastin-like protein copolymer SELP-47K containing tandemly repeated amino acid sequence blocks from silk, GAGAGS, and elastin, GVGVP, was fabricated into microdiameter fibers using a wet-spinning technique. Raman spectral analysis revealed the formation of antiparallel beta-sheet crystals of the silk-like blocks. Dry SELP-47K fibers display the dependence of mechanical properties such as Young's modulus on fiber diameter, suggesting more oriented and crystallized molecular chains in small-diameter fibers. Additionally, a brittle fracture mode was identified for dry fibers by SEM analysis of fracture surfaces. Hydration dramatically influenced the mechanical behavior of SELP-47K fibers. In contrast to the high tensile strength and limited strains to failure of dry fibers, fully hydrated SELP-47K fibers possessed strains to failure as high as 700%. Furthermore, upon chemical cross-linking, a tensile mechanical strength up to 20 MPa was achieved in hydrated fibers without compromising their high deformability. By combing the silk- and elastin-derived sequences into a single SELP-47K protein polymer, we demonstrated that protein fibers with high tensile strength and high deformability can be fabricated.

Transient dynamic mechanical properties of resilin-based elastomeric hydrogels

“…The highly dynamic behavior of the flexible RLP chains is reported to be derived from hydrogen bond exchange, charge interactions, and the high polarity of the side chains; the elastomeric properties of the RLP-based materials here is consistent with this behavior. (Kappiyoor et al, 2011) The applied shear stresses (50–4000 Pa) in our experiments, selected for deformation of the RLP-based hydrogels to physiologically relevant strains, are significantly lower than those applied (30 KPa–0.8 MPa) in the characterization of elastin-like polypeptide- (ELP) and silk-elastin like polypeptide(SELP)-based biomaterials (McPherson et al, 1992; Wu et al, 2008; Qiu et al, 2009, 2010; Teng et al, 2009), owing to the fact that the RLP-based hydrogels are more soft and extensible than the previously reported materials.…”

Silk-elastin-like protein biomaterials for the controlled delivery of therapeutics

“…Fourier transform infrared spectroscopy spectra [68] and circular dichroism spectra [25, 68] confirmed that insoluble tightly packed beta sheet structures were formed in silk-like blocks in SELPs. The silk units in SELPs impart the mechanical stability by forming beta sheet physical crosslinks [49, 64] and facilitate the self-assembly of SELPs into micellar-like nanoparticles by phase separation [25]. The elastin-like block (GXGVP) in SELPs is adopted from mammalian tropoelastin [98, 99].…”

Electrodeposited Gels Prepared from Protein Alloys

“…The infrared signatures of the proteins were monitored throughout the chemical modification process (Figure 3B). A broad N-H wagging absorption at 700–900 cm −1 attributed to the primary amine groups of lysine residues on tropoelastin disappeared after the acetylation reaction, as accompanied by the appearance of a C–N stretching vibration peak at 1034 cm −1 attributed to secondary amine groups [20,21]. After enzymatic couplings between S and E′, an increase in the phenolic C–O stretching band was observed at 1290 cm −1 and a decrease in the di-substituted aromatic ring C–C stretching band associated with tyrosine at 1512 cm −1 , both suggesting the formation of dityrosine bonds [22,23].…”