Stamov Dimitar, Grimmer Milauscha, Salchert Katrin, Pompe Tilo, Werner Carsten
Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials Dresden, Hohe Strasse 6, Dresden, Germany.
Biomaterials. 2008 Jan;29(1):1-14. doi: 10.1016/j.biomaterials.2007.09.009. Epub 2007 Sep 24.
Collagen type I fibrils, reconstituted in vitro in the presence of heparin, exhibit an unusually thick and straight shape. A detailed structural analysis by scanning force and scanning electron microscopy revealed a non-linear dependence in size distribution, width-to-length ratio, and morphology over a wide range of glycosaminoglycan (GAG) concentrations. By varying molecular weight, degree of sulphation, charge, and concentration of different GAGs we are able to correlate the morphological data with kinetic turbidimetric measurements, and quantitation of fibril-bound GAG. The experiments imply a pronounced impact of the prenucleation phase on the cofibril morphology as a result of the strong electrostatic interaction of heparin with tropocollagen. Heparin is assumed to stabilize the collagen microfibrils and to enhance their parallel accretion during cofibrillogenesis with preservation of the typical asymmetric collagen banding pattern. The heparin quantitation data show heparin to be intercalated as a linker molecule with one specific binding site inside the cofibrils. The reconstituted cofibrils with their unusual morphology and GAG intercalation-a phenomenon not reported in vivo-can be expected to exhibit interesting mechanical and biochemical behaviours as a biomaterial for extracellular matrix scaffolds.
在肝素存在的情况下体外重构的I型胶原纤维呈现出异常粗大且笔直的形状。通过扫描力显微镜和扫描电子显微镜进行的详细结构分析显示，在广泛的糖胺聚糖（GAG）浓度范围内，尺寸分布、宽长比和形态存在非线性依赖关系。通过改变不同GAG的分子量、硫酸化程度、电荷和浓度，我们能够将形态学数据与动力学比浊法测量以及纤维结合GAG的定量相关联。实验表明，由于肝素与原胶原的强静电相互作用，成核前阶段对共纤维形态有显著影响。肝素被认为可稳定胶原微纤维，并在共纤维形成过程中增强其平行聚集，同时保留典型的不对称胶原条纹模式。肝素定量数据表明，肝素作为连接分子插入共纤维内部的一个特定结合位点。重构的共纤维具有异常形态和GAG插入现象——这是体内未报道的现象——有望作为细胞外基质支架的生物材料表现出有趣的力学和生化行为。
