Müller-Herrmann Susanne, Scheibel Thomas
Lehrstuhl Biomaterialien, Universität Bayreuth, Universitätsstraße 30, D-95447 Bayreuth, Germany.
ACS Biomater Sci Eng. 2015 Apr 13;1(4):247-259. doi: 10.1021/ab500147u. Epub 2015 Mar 12.
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 cross-linking of the scaffolds was assessed thereon. In addition to two bacterial proteolytic model enzymes, protease type XIV from (PXIV) and collagenase type IA from (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.
生物材料在体内的性能在很大程度上受其稳定性以及降解速率和程度的影响。例如，用于组织工程应用的材料必须具有机械稳定性，以支持细胞黏附和增殖而不塌陷。另一方面，它们需要逐渐被天然细胞外基质替代，并且必须是（缓慢）可生物降解的。因此，能够调节生物材料的降解行为至关重要。重组生产的蜘蛛丝蛋白已被证明是用于医学应用的多功能生物聚合物。它们可以加工成各种形态，并且通过化学或基因修饰，可以根据特定需求调整其性能。此外，体内实验证实了对某些蜘蛛丝缺乏免疫反应。在本研究中，分析了重组蜘蛛丝蛋白eADF4(C16)在溶液中以及加工成颗粒、薄膜和非织造网时的降解行为，并评估了支架交联对其的影响。除了在所有实验中使用的两种细菌蛋白水解模型酶，来自[具体来源1]的蛋白酶XIV（PXIV）和来自[具体来源2]的IA型胶原酶（CHC）外，还使用了几种重组人基质金属蛋白酶（MMPs）和一种弹性蛋白酶来研究可溶性eADF4(C16)的降解。对于可溶性eADF4(C16)，所有降解动力学都相似。在eADF4(C16)支架的情况下，PXIV和CHC之间存在明显差异。在CHC存在下，所有支架对蛋白水解降解的稳定性都比在PXIV存在下更高。此外，颗粒的降解速度明显快于薄膜，非织造网表现出最高的蛋白水解稳定性。支架的化学交联导致降解速率和程度均降低。
