氟涂层与β-磷酸三钙涂层对AZ31B镁合金降解行为影响的实验研究

Experimental study on effects of fluoride and β-TCP coating on the degradation behavior of magnesium alloy AZ31B in vitro

目的探讨氟涂层与β-磷酸三钙(β-TCP)涂层对AZ31B镁合金降解行为的影响,并进行比较。方法本研究于2008年6月至2009年3月在中国医科大学完成。将采用化学法进行氟涂层的AZ31B镁合金(氟涂层组)与采用低温化学沉积法进行β-TCP涂层的AZ31B镁合金(β-TCP涂层组)及无涂层AZ31B镁合金(对照组)分别浸泡于骨细胞培养基DMEM溶液,观察浸泡1、3、5、7、14d时各组DMEM溶液pH值的变化。并采用扫描电镜观察各组材料浸泡前和浸泡7d后的表面形貌。结果 (1)各组不同浸泡时间DMEM溶液pH值的变化:对照组pH值持续升高;氟涂层组无明显变化;β-TCP涂层组浸泡3d内,pH值无明显变化,之后pH值明显升高。(2)表面形貌:浸泡前,对照组材料表面相对光滑;氟涂层组材料表面致密、光滑,有一些同向的纹理;β-TCP涂层组材料表面为团块状结晶,粗糙度比涂层前明显增大。浸泡7d后,对照组材料表面呈龟裂状;氟涂层组材料表面无明显改变,可见散在腐蚀凹陷;β-TCP涂层组材料表面块状晶体逐渐发生球化,部分晶体有溶解迹象呈团状。结论氟涂层和β-TCP涂层可以在一定程度上控制AZ31B镁合金初期降解速度,其中氟涂层比β-TCP涂层更加有效。

Objective To study the viability of using magnesium alloy AZ31B coated with fluoride and β-TCP as biode-gradable bone scaffolds materials. Methods This research was done from June of 2008 to March of 2009 in China Medical University. Pieces of magnesium alloy AZ31B uncoated and coated with fluoride and with β-TCP were immersed in DMEM culture medium respectively. The changes of the DMEM culture medium＇ s pH valules and morphology of magnesium alloy AZ31B uncoated or coated was evaluated after immersion. Results The pH values of DMEM solution immersed by magnesium alloy AZ31B uncoated rose significantly, while that immersed by magnesium alloy AZ31B coated with flouride kept steady, and that immersed by magnesium alloy AZ31B coated with β-TCP kept steady within 3 days and then rose significantly. After being immersed for seven days, the surface of magnesium alloy AZ31B uncoated was corroded severely, while the surface of magnesium alloy AZ31B coated with fluoride changed little and appeared some pits, and the surface of magnesium alloy AZ31B coated with β-TCP appeared some nodularization and some crystals became dissolved. Conclusion Being coated with fluoride and with β-TCP can control the biodegradation rate of magnesium alloy AZ31B to some extent and being coated with fluoride is more effective than with β-TCP.