【作者】 刘鹤；

【导师】 马宁；

【作者基本信息】 吉林大学 ， 口腔临床医学， 2014， 硕士

【摘要】 镁(Magnesium, Mg)作为一种新兴的生物材料，具有与人体骨相近的密度和弹性模量，能耐受一定的压力，且能避免应力遮挡效应；镁具有良好的生物相容性和生物降解性；镁还能促进骨愈合，因此镁作为骨移植物在口腔颌骨缺损的修复上有很大的潜力。但是镁在体内降解过快，不能对骨组织缺损起到很好的支撑作用。因此本实验采用纳米羟基磷灰石(nano-hydroxyapatite, nHA)与聚乳酸羟基乙酸聚合物[poly(lactic-co-glycolic acid), PLGA]对镁进行了合金化及表面改性处理，获得一种新的生物复合材料，以期改善镁的内部结构及耐蚀性能，从而减缓镁的降解速率。本实验以镁粉和nHA为原料，采用粉末冶金法制备nHA/Mg合金，将PLGA与nHA溶于氯仿中，采用浸涂提拉法制备PLGA、nHA/PLGA涂层，通过SEM测试手段分析了复合材料的表面形态及腐蚀后形态，研究了降解速率与时间的关系，探讨了复合材料在腐蚀液中的PH值变化规律。粉末冶金法获得的nHA/Mg合金具有比较理想的组织结构，通过浸涂提拉法获得的涂层表面平整、厚度均匀、无明显裂纹和孔洞缺陷。随着涂覆次数的增加，涂层的厚度和质量随之增加，并成正比例关系。静态腐蚀实验表明，涂层的加入能够有效地减缓复合材料的腐蚀速度，延长其在腐蚀液的存留时间，降低材料腐蚀液的pH值，改善复合材料的生物相容性。通过本实验获得的nHA/PLGA/Mg生物复合材料具有较好的组织结构，良好的生物相容性及可降解性，降解产物可完全被人体吸收，是一种安全无公害的材料。该实验结果为镁合金应用到临床颌骨缺损的修复提供了理论依据和实验基础，具有良好的临床应用前景。更多还原

【Abstract】 Magnesium as a new material with suitable mechanical strength and elasticmodulus. It can withstand a certain pressure, and it can avoid the stress shieldingeffect; magnesium percesses biocompatible biodegradable; magnesium can promotebone healing. So magnesium alloy as bone graft in the repair of oral mandibulardefects has great potential.However, magnesium has rapid degradation of magnesiumin the body.So it can not play a good part in supporting bone tissuedefects.Therefore,the present experiment studied nHA and PLGA on magnesium withalloying and surface modification method,geting a new bio-composite material inorder to improve the internal structure and corrosion resistance of magnesium,andslow down the rate of degradation of magnesium.In this experiment,we mixed nano-hydroxyapatite into magnesium powder toprepare nHA/Mg alloy by powder metallurgy method.The PLGA and nHA whichwere dissolved in chloroform were used to prepare PLGA and nHA/PLGA coatingswith dipping pulling method.By means of SEM we analysisd the surface morphologyof composites and morphology after etching patterns.Then we studied the relationshipbetween the degradation rate and time,and explored the pH value of the compositevariation in the corroding solution.NHA/Mg alloys obtained by powder metallurgy method have idealorganizational structure.Coatings obtained by dipping pulling method have roughsurface,uniform thickness,and no obvious cracks and other holes.With increasing thenumber of coating, thickness and quality of coating increased.There is a positiverelationship between them.Static corrosion tests showed that the coating canefficiently slow down the corrosion rate of the composite materials,extend theresidence time in the body,reduce the PH value of the etchant materials and improvethe biocompatibility of the composite. NHA/PLGA/Mg biocomposite materialobtained by this experiment has reasonable space structure, favorable biocompatibilityand biodegradability.The degradation products can be fully absorbed by the body.It isa safe and pollution-free materials.The experimental results provides a theoreticalbasis and experimental basis for the clinical application of magnesium alloy onmandibular defect repair.NHA/PLGA/Mg biocomposite material has good prospectsfor clinical application.更多还原