釉质仿生矿化模型的研究

A model for biomimetic mineralization of enamel

目的:构建釉质生物矿化的模型,包括有机基质模板(类釉原蛋白寡肽序列)的建立和无机离子供体(包裹钙磷离子的温度敏感性脂质体)的合成,体外实现类釉质样结构的再矿化。方法:首先通过标准固相法合成所需"类釉原蛋白"寡肽[(Gln-Pro-Ala)4-Thr-Lys-Arg-Glu-Glu-Val-Asp],并用CaCl_2溶液诱导其进行自组装;其次采用二棕榈酰磷脂酰胆碱和二肉豆蔻卵磷脂为原料,通过相交融合法分别合成包裹钙、磷离子的温度敏感性脂质体;最后在37℃时,将酸蚀后的牙片浸泡在包裹钙、磷离子的脂质体与寡肽的混悬液中,作为实验组。将酸蚀后的牙片浸泡在包裹钙磷离子的脂质体混悬液中,作为对照组,促进脱矿后的釉质再矿化。矿化后的牙片通过扫描电镜(SEM)、傅立叶变换红外光谱仪(FTIR)和X射线衍射仪(XRD)进行表征。结果:实验组的脱矿釉质表面均匀有序的沉积了一层釉质样的羟基磷灰石晶体(HA)结构,而对照组只沉积了较少量无序的HA晶体。结论:通过类釉原蛋白寡肽有机矿化模板的建立,以及仿生釉质矿化过程中钙、磷离子的输送,构建了釉质仿生矿化模型,并实现了脱矿釉质表面类釉质样微结构的再生。

Objective：We designed a novel strategy for enamel remineralization,including an amelogenin-like oligopeptide as templates for controlling the nucleation and growth of HA crystals and synthesized calcium-and phosphate-loaded temperature sensitive liposomes supplying calcium and phosphate ion,to induce HA crystals and promote biomimetic mineralization.Methods：A novel polyanion amelogenin-inspired oligropeptide（Gln-Pro-Ala）4-Thr-Lys-Arg-Glu-Glu-Val-Asp） was synthesized by standard solid-phase,and induced self-assembly with CaCl_2 solution.Secondly,the calcium/phosphate phosphate loaded liposomes were prepared using the interdigitation-fusion method.The liposomes were composed of 1,2-bis（palmitoyl）-sn-glycero-3-phosphocholine and 1,2-bis（myristoyl）-sn-glycero-3-phosphocholine.Lastly,the experimental groups treated with mixture solution of liposomes and polyanion peptide.But the control groups were treated with the liposomes solution.These two groups were characterized by scanning electron microscope（SEM）,Fourier transform infrared spectroscopy（FTIR） and X-ray Diffraction（XRD）.Results：The experimental groups showed that the rodlike crystals almost fully covered the etched enamel surface,and distributed evenly to make the surface smooth.In contrast,the control groups showed that there was only small amount of HA crystal deposition,and the precipitate distributed randomly.Conclusions：The self-assembly amelogenin-inspired oligopeptide polyanion peptide combining with temperature sensitive Ca2 ＋and PO3-4loaded liposomes can effectively induce biomimetic mineralization of enamel.