Enzymatic Degradation of Films, Particles, and Nonwoven Meshes Made of a Recombinant Spider Silk Protein

Abstract

The performance of biomaterials in vivo is largely influenced by their stability and the rate and extent to which they degrade. Materials for tissue engineering applications, for example, have to be mechanically stable to support cell adhesion and proliferation without collapsing. On the other hand they need to be replaced gradually by native extracellular matrix and have to be (slowly) biodegradable. Therefore, it is of critical importance to be able to tune the degradation behavior of a biomaterial. Recombinantly produced spider silk proteins have been shown to be versatile biopolymers for medical applications. They can be processed into a variety of morphologies, and by chemical or genetic modification the properties can be adjusted to specific demands. Furthermore, in vivo experiments confirmed the lack of immunological reactions toward certain spider silks. In this study the degradation behavior of the recombinant spider silk protein eADF4(C16) in solution as well as processed into particles, films and nonwoven meshes was analyzed, and the impact of crosslinking of the scaffolds was assessed thereon. In addition to two bacterial proteolytic model enzymes, protease type XIV from Streptomyces griseus (PXIV) and collagenase type IA from Clostridium histolyticum (CHC) used in all experiments, several recombinant human matrix metalloproteinases (MMPs) and one elastase were used in studying degradation of soluble eADF4(C16). For soluble eADF4(C16) all degradation kinetics were similar. In case of eADF4(C16) scaffolds significant differences were observable between PXIV and CHC. All scaffolds were more stable toward proteolytic degradation in the presence of CHC than in the presence of PXIV. Further, particles were degraded significantly faster than films, and nonwoven meshes showed the highest proteolytic stability. Chemical cross-linking of the scaffolds led to a decrease in both degradation rate and extent.

<p>Enhanced Antibacterial Activity of Se Nanoparticles Upon Coating with Recombinant Spider Silk Protein eADF4(κ16)</p>

“…48 Compared to these polymers, the positively charged spider silk protein eADF4(κ16) has several advantages, including good biocompatibility, low immunogenicity, nontoxicity, and biodegradability. [49][50][51][52][53][54] Recombinant spider silk protein eADF4(κ16) is a variant of polyanionic eADF4(C16), where the naturally occurring glutamic acid residue in the sequence of the eADF4 core C-module (GSSAAA AAAAAS GPGGYG PENQGP SGPGGYGPGGP) is replaced with lysine. 49 eADF4(C16) is based on the consensus core sequence of the garden spider Araneus diadematus dragline silk fibroin 4 (ADF4) and comprises a consensus (C) module repeated 16 times.…”

Spider dragline silk composite films doped with linear and telechelic polyalanine: Effect of polyalanine on the structure and mechanical properties

“…These recombinant spider silk materials consist of a partial repetitive sequence or a combination of the repetitive domain and terminal domain(s) extracted from the whole sequence of spider silk proteins. Films have also been prepared by molding or spin-coating of recombinant spider silk solutions in an aqueous buffer or 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) 14 , 22 , 23 .…”

Spider Silk for Tissue Engineering Applications

“…Slow degradation rates are advantageous in applications, such as in NGCs where the neuronal support can remain for weeks to months, while within the nerve regeneration takes place. However, the degradation can also be adjusted by engineering silk variants with matrix metalloproteinase (MMP) degradation sites [91].…”