Hydroxyapatite Crystal Growth on Modified Collagen I-Templates in a Model Dual Membrane Diffusion System†
Hydroxyapatite Crystal Growth on Modified Collagen I-Templates in a Model Dual Membrane Diffusion System†
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DOI：
10.1002/zaac.200500195
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发表时间：
2005-08
期刊：
影响因子：
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通讯作者：
H. Ehrlich;T. Douglas;D. Scharnweber;T. Hanke;René Born;S. Bierbaum;H. Worch
中科院分区：
文献类型：
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作者：
H. Ehrlich;T. Douglas;D. Scharnweber;T. Hanke;René Born;S. Bierbaum;H. Worch
蛋白聚糖（PG）在矿化组织中的发现证实了它们在生物矿化过程中的作用，但未能给出关于可能的详细相互作用机制的答案。已知PG（尤其是核心蛋白聚糖）的去糖基化是体内生物矿化的先决条件，因此在矿化实验中使用双膜扩散法与I型胶原一起研究了葡萄糖醛酸（GA）（作为不同蛋白聚糖和糖胺聚糖共有的单体）和核心蛋白聚糖。结果表明，在纤维形成条件下，葡萄糖醛酸和核心蛋白聚糖以不同程度与胶原结合。与核心蛋白聚糖相反，GA的结合导致原纤维形态和带型的变化。未修饰的胶原模板和用GA和核心蛋白聚糖修饰的胶原模板的矿化导致形成不同的磷酸钙相。羟基磷灰石（HAP），作为在所选的实验条件下的生物学稳定的产物，仅在用GA改性的胶原的情况下形成。为了帮助解释这种效果，提出并讨论了葡萄糖醛酸与胶原蛋白通过非酶糖化途径相互作用的可能机制。HAP形成的刺激被解释为引入酸性GA-羧酸基团，其允许与未修饰的胶原分子相比增加钙离子的静电结合。以这种方式改性的基板应随后作为矿化过程的模型模板，以使有关的机制，其中酸性基团通过单体的结构以及原纤维的结构影响胶原蛋白的生物矿化的推论。
The finding of proteoglycans (PG) in mineralized tissues confirms their role in the biomineralization process, but fails to give answers regarding possible detailed mechanisms of interaction. As deglycosilation of PG (especially decorin) is known to be a prerequisite for biomineralisation in vivo, glucuronic acid (GA), as a monomer common to different proteoglycans and glycosaminoglycans, and decorin were studied in mineralization experiments together with collagen type I using the dual membrane diffusion method. It was shown that under fibrillogenesis conditions glucuronic acid and decorin bind to a different extent to collagen. Binding of GA, in contrast to decorin, results in changes in both the fibril morphology and the banding pattern. The mineralization of unmodified collagen templates and of those modified with GA and decorin results in the formation of different calcium phosphate phases. Hydroxyapatite (HAP), as the thermodynamically stable product under the chosen experimental conditions, is formed only in the case of collagen modified with GA. To aid interpretation of this effect, a possible mechanism of glucuronic acid interaction with collagen by a non-enzymatic glycation pathway is proposed and discussed. Stimulation of HAP formation is explained by the introduction of acidic GA-carboxylate groups that allow an increase of the electrostatic binding of calcium ions compared to unmodified collagen molecules. Substrates modified in this way should subsequently serve as model templates for the mineralization process in order to make deductions about the mechanism by which acidic groups affect the biomineralization of collagen via the structure of the monomers as well as the architecture of the fibrils.