丝蛋白为单分子模板诱导牙体组织样羟基磷灰石体外仿生合成

Controlled Crystallization of Tooth-like Hydroxyapatite under silk protein polymer layer.

目的依据生物矿化的有机基质调控理论,实现牙体硬组织样羟基磷灰石的体外仿声合成。方法运用碳乙基二亚胺盐酸盐和N-羟基丁二酰亚胺介导缩合反应将蚕丝蛋白以肽键键合到牙体组织表面,覆盖原来的-NH3位点,以过饱和矿化液作为离子供体实现晶体生长。结果所得晶体呈矮柱状,30~50nm长,垂直于牙体组织表面,相互平行排列。经X射线衍射（XRD）和扫描电镜（SEM）检测证实新生晶体为羟基磷灰石,硬度接近正常牙本质。结论本研究初步实现了牙体组织样羟基磷灰石的体外仿生合成。

Objective Based on the basic theory of molecular recognition,we design a organic molecules model to induce the crystallization of hydroxyapatite to synthesized tooth-like calcium phosphate/hydroxyapatite under a controllable way in vitro.Methods The cross-linking of silk protein on the tooth surface and extraneous collagen was optimized by varying the molar ratio of N,N-（3-dimethylaminopropyl）-N′-ethyl-carbodiimide hydrochloride（EDC）and N-hydroxysuccinimide（NHS）at a constant EDC concentration.CaCl2 and Na3PO4-12H2O solutions were added after the crosslinking process.Results The obtained composite were characterized by X-ray diffraction（XRD）and scanning electron microscopy（SEM）.The results showed that the dentinal tubule were blocked by neonatal hydroxyapatite layer which has a continuous structure of columns crystal with size of 30~50nm.Furthermore,there were column crystal with parallel direction inside,similar to the crystal array in the top of enamel rod.Conclusion This study showed that the specific organic molecule model can be used as a potential effective crystal growth modifier.