釉基质蛋白对双重酸蚀后纯钛表面磷灰石生成的影响

Effect of enamel matrix proteins on the growth of apatite coating on dual thermo-etching modified titanium

背景:为提高钛种植体植入后的生物活性,常采用各种表面改性技术。目的:研究釉基质蛋白对双重热酸蚀纯钛表面仿生矿化沉积磷灰石层的影响。方法:提取猪未萌恒牙胚表面的釉基质蛋白并进行验证,纯钛片经抛光清洗后进行双重热酸蚀处理,然后放入含不同浓度釉基质蛋白的饱和矿化液中矿化7 d,对照组为不含釉基质蛋白的钙磷过饱和液。扫描电镜观察试件表面形貌,X射线能谱及X射线衍射分析涂层的元素成分及晶相结构。结果与结论:经双重酸蚀处理后的钛片表面形成规则凹坑状的粗糙表面,经过7 d的矿化实验后,不添加釉基质蛋白的对照组试件上未见明显矿化涂层的形成。加入釉基质蛋白的实验组试件表面可形成矿化涂层,且随釉基质蛋白浓度的增加,矿化涂层的量及形态发生改变。能谱分析结果显示:矿化涂层中的主要元素为钙、磷、碳和氧,钙磷摩尔比在1.32-1.41之间。X射线衍射结果显示纯钛试件表面的沉积物为碳羟基磷灰石。提示釉基质蛋白可以促进双重酸蚀处理后的纯钛表面更快地生成磷灰石涂层。釉基质蛋白对纯钛表面磷灰石涂层的影响呈浓度相关性。

BACKGROUND： Various surface modification techniques have been used to improve the bioactivity of titanium implant in vivo. OBJECTIVE： To investigate the effects of enamel matrix proteins（EMPs） on the growth of apatite coatings on dual thermo-etching treated pure titanium. METHODS： EMPs were extracted from porcine tooth germs and then were identified. Dual thermo-etching was applied to treat titanium samples following polished, and then immersed in a blank simulated body fluid supersaturated calcification solution（control group） or supersaturated calcification solution containing different concentrations of EMPs for 7 days. The morphology of samples was observed using scanning electron microscope, and element components and crystal structures of the apatite coatings were analyzed by energy dispersive spectrometer and X-ray diffraction. RESULTS AND METHODS： After double-etching, a pit-like rough surface was observed on the titanium plate. After 7-day mineralization, in the control group, no overt calcium-phosphate deposits were found on the titanium surface; however, in the experimental groups, there were calcium-phosphate deposits, whose quantity and morphology changed with increasing concentrations. Energy dispersive spectrometer showed that the main element components of the mineralized coating included calcium, phosphorus, oxygen and carbon, and the calcium-phosphate ratio ranged from 1.32 to 1.41. The apatite coatings were proved to be carbonate hydroxyapatite by X-ray diffraction. To conclude, EMPs promote apatited deposition on pure titanium surfaces in a concentration-dependent manner.