The calcification of fibrin in vitro
The calcification of fibrin in vitro
复制标题
DOI：
10.1016/s0022-0248(00)00455-3
复制
发表时间：
2000-07-01
影响因子：
1.8
通讯作者：
Dalas, E
中科院分区：
文献类型：
--
作者：
Koutsopoulos, S;Dalas, E
在目前的工作中，我们采用纤维蛋白，以评估其诱导生物矿化的能力。凝血是凝血系统中一个非常重要的因素。在结构上，纤维蛋白是有序的有机基质，其具有每230埃重复的周期性结构。羟基磷灰石、HAP和磷酸八钙（OCP）是最令人感兴趣的磷酸钙盐。羟基磷灰石是生物学上最稳定的磷酸钙，主要用作生物钙化过程研究的模型化合物。另一方面，磷酸八钙已被提议作为羟基磷灰石的前体，其形成在两种盐过饱和的溶液中动力学上是有利的。用恒组成法研究了HAP和OCP在纤维蛋白上的结晶动力学。HAP结晶的发作后立即开始引入衬底在过饱和溶液中。与HAP不同，在HAP和OCP都过饱和的溶液中，在OCP沉淀物出现之前观察到结晶诱导期。利用经典的均质成核理论导出的成核速率方程，计算了HAP和OCP的界面能和临界成核尺寸。磷酸盐被所研究的生物分子广泛吸收。吸附对离子强度和介质pH值的依赖性表明静电力的明显贡献。有争议的是，在37 ℃，pH = 7.4的0.15 M NaCl支持电解质中，在含有1 x 10（-4）至5 x 10（-3）M氯化钙的溶液中，钙离子没有表现出任何可检测的吸附。从以上结果可以得出，HAP在纤维蛋白上的形成可以通过无机磷酸盐在生物基质上的吸附来引发。(C)2000 Elsevier Science B. V.保留所有权利。
In the present work we employed fibrin in order to assess its capability to induce biological mineralization. Fibrin is a very important factor in the blood-clotting system. Structurally, fibrin is an ordered organic matrix which has a periodic structure that repeats every 230 Angstrom. Hydroxyapatite, HAP and octacalcium phosphate (OCP) are the most interesting calcium phosphate salts. Hydroxyapatite is thermodynamically the most stable calcium phosphate which is mostly used as a model compound for the study of biological-calcification processes. On the other hand, octacalcium phosphate has been proposed as a precursor of hydroxyapatite whose formation is favoured kinetically in solutions supersaturated to both salts. The kinetics of crystallization of HAP and OCP on fibrin were studied using the constant composition technique. The onset of HAP crystallization started immediately after introducing the substrate in the supersaturated solution. Unlike HAP crystallization induction periods were observed before the appearance of OCP precipitate in a solution supersaturated with respect to both HAP and OCP. Using nucleation rate equations derived from the classical homogeneous nucleation theory, interfacial energies and the size of the critical nucleus for both HAP and OCP were calculated. Phosphate was taken up extensively by the biological molecule studied. The dependence of adsorption upon ionic strength and pH of the medium suggests an appreciable contribution of electrostatic forces. Controversially calcium ions did not exhibit any detectable adsorption from solutions containing calcium dichloride at concentrations ranging from 1 x 10(-4) to 5 x 10(-3) M in 0.15 M NaCl supporting electrolyte, 37 degrees C, pH = 7.4. From the results above it follows that formation of HAP on fibrin may be initiated via adsorption of inorganic phosphate on the biological substrate. (C) 2000 Elsevier Science B.V. All rights reserved.