Complete Recombinant Silk-Elastinlike Protein-Based Tissue Scaffold

Abstract

Due to their improved biocompatibility and specificity over synthetic materials, protein-based biomaterials, either derived from natural sources or genetically engineered, have been widely fabricated into nanofibrous scaffolds for tissue engineering applications. However, their inferior mechanical properties often require the reinforcement of protein-based tissue scaffolds using synthetic polymers. In this study, we report the electrospinning of a completely recombinant silkelastinlike protein-based tissue scaffold with excellent mechanical properties and biocompatibility. In particular, SELP-47K containing tandemly repeated polypeptide sequences derived from native silk and elastin was electrospun into nanofibrous scaffolds, and stabilized via chemical vapor treatment and mechanical preconditioning. When fully hydrated in 1x PBS at 37 °C, mechanically preconditioned SELP-47K scaffolds displayed elastic moduli of 3.4 to 13.2 MPa, ultimate tensile strengths of 5.7 to 13.5 MPa, deformabilities of 100 to 130% strain, and resilience of 80.6 to 86.9%, closely matching or exceeding those of protein-synthetic blend polymeric scaffolds. Additionally, SELP-47K nanofibrous scaffolds promoted cell attachment and growth demonstrating their in vitro biocompatibility.

Chemoenzymatic Synthesis of Polypeptides for Use as Functional and Structural Materials

“…In contrast, CPDY is characterized as an exopeptidase that typically cleaves only amide bonds at C-termini. Therefore, CPDY-catalyzed polymerization avoids the hydrolysis of the polypeptide backbones of pre-existing polypeptides, resulting in efficient suppression of the broadening of the molecular weight distribution of the products that Methyl, [49,54] ethyl, [50][51][52][53][54][55][56] benzyl [54] Proteinase I, [49] papain (13)(14)(15)(16)(17)(18) [50][51][52][53][54][55][56] Glycine Methyl, [54] ethyl, [49,51,54,55] benzyl [54] Proteinase I, [49] papain (10)(11)(12)(13)(14)(15)(16)(17)(18)(19) [51,54,55] l-Leucine…”

“…Methyl, [57,58,63] ethyl [46,49,52,56,62] Proteinase I, [49] papain (4)(5)(6)(7)(8)(9)(10)(11)(12), [46,52,[56][57][58][59][60]62] bromelain (6.5-7.9), [46,59] α-chymotrypsin (8.2-9.4), [46,59,61] protease SG (8.5), [59] CPDY (6) [63] l-Isoleucine…”

“…Ethyl, [49] isopropyl [23,24] Proteinase I, [49] papain (5)(6)(7)(8)(9)(10)(11)(12)(13)(14), [60,67,68] α-chymotrypsin [23,24] l-Lysine…”

“…The most representative example is resilin, a structural protein that is found in insects, such as dragonflies and fleas. [9,10] Resilin comprises randomly coiled polypeptide chains that are cross-linked by multiple di-and trityrosine moieties and displays outstanding physical properties, such as extremely high elasticity and high fatigue lifetime. Another example can be found in melanins, a family of natural pigments produced by the polymerization of tyrosine-based molecules that protect living forms from photoinduced damages.…”

“…[118,119] As an α,α-disubstituted amino acid, 2-aminoisobutyric acid (Aib) is known to strongly favor helix formation when incorporated into a polypeptide backbone. Indeed, the introduction of Aib units compels oligopeptides to adopt helical conformations, such as α-and 3 10 -helices. [120][121][122] However, the chemoenzymatic polymerization of Aib ethyl ester resulted in no polymer formation due to a mismatch with the substrate recognition sites in proteases.…”