磷酸钙在凝胶体系中的仿生矿化研究

Biomimetic mineralization of calcium phosphates in gel system

通过模拟牙釉质的生物矿化过程,在琼脂凝胶体系中研究两种磷酸钙晶体—磷酸八钙(Ca8H2(PO4)6.5H2O,OCP)和羟基磷灰石(Ca10(PO4)6(OH)2,HAP)的矿化过程:分别研究了不同pH值(pH=6.5,7.0,7.5)条件下以及添加I型胶原蛋白的凝胶体系中矿化所形成的磷酸钙晶体的组成和形貌。在凝胶体系中,当pH=6.5时主要形成OCP,形貌为较大尺寸的片状;pH=7.0,则形成了较短片状OCP与针状HAP的混晶;pH=7.5,则主要形成针状形貌的HAP。此外,当添加Ⅰ型胶原蛋白后,在pH=6.5时则主要形成较大尺寸的片状HAP,且互相平行排列成束。由实验结果可知:pH对凝胶体系中仿生合成的磷酸钙晶体的组成和形貌具有一定的调控作用,而Ⅰ型胶原蛋白则有利于诱导形成片状HAP晶体并且使之排列呈束状,其结构类似牙釉质晶体。

The biomineralizaion process of two kinds of calcium phosphates--octacalcium phosphate （Ca8H2（PO4）6·5H2O,OCP） and hydroxyapatite （Ca10 （PO4 ）6 （OH）2, HAP） were studied in agar gel system mimicking tooth enamel formation. The composition and morphology of the calcium phosphates deposited in the gel system were investigated by adjusting the pH value to 6, 5, 7.0 and 7.5 respectively, as well as adding type I collagen. The results show that OCP crystals with relatively big plate-like morphology are predominant at pH = 6.5, and both short plate-like OCP crystals and needle-like HAP crystals are formed at pH = 7.0, while needle-like HAP crystals are predominant at pH = 7.5. Besides, by adding type I collagen to the gel system at pH = 6.5, big plate-like HAP crystals which arranged paralleled to each other are obtained. It can be found that the pH value can affect the formation of plate-like OCP crystals and needle-like HAP crystals in gel system. The type I collagen in the gel system can help to induce the formation of bundles of plate-like HAP crystals, mimicking tooth enamel crystallites in configuration.