【摘要】 镁金属在生理环境中的降解速率和生物活性改善有助于其在生物医用领域的应用推广,合金化处理和表面改性是2种有效的途径。本研究针对镁-钙合金（ZQ）提出一种新的改性方法,利用水热处理、电泳沉积和电化学沉积相结合,在其表面上构建羟基磷灰石/氧化石墨烯/氢氧化镁（HA/GO/Mg（OH）₂）复合涂层。扫描电镜（SEM）和X射线衍射（XRD）分析证实,该复合涂层样品（ZQ-HEP）表面逐层形成了外层纳米薄片HA、中层絮片状GO、及内层Mg（OH）2纳米片的复合涂层。体外电化学耐腐蚀性测试分析表明,涂层化的ZQ-HEP 比未处理ZQ样品在磷酸缓冲盐溶液（PBS）中有更优的耐蚀性。通过构建的体内兔股骨髁骨折模型,评价表面改性前后ZQ样品的骨折修复效果。术后大体观察、影像学和组织学分析证实,体内生理环境下ZQ-HEP螺钉的析氢速率比ZQ螺钉低,皮下气肿现象减少。同时,ZQ-HEP螺钉因其更优的耐蚀性,在术后4周内可较好地保持其材料的完整性,同时介导更多的新骨长入,进而实现骨折的快速愈合。本研究提出的GO/HA/Mg（OH）₂复合涂层构建策略,可在调控镁金属降解速率的同时,显著提升其成骨修复效果,具有良好的临床应用前景。更多还原

【Abstract】 Improving the degradation rate and bioactivity of magnesium in physiological environment is helpful to its application in biomedical field.Alloying treatment and surface modification are two effective ways.In the present study,a novel surface modification strategy,i.e.hydroxyapatite/graphene oxide/magnesium hydroxide(HA/GO/Mg(OH)2) composite coating constructed on the surface of magnesium-calcium alloy by the combination of hydrothermal treatment,electrophoretic deposition and electrochemical deposition,were proposed for magnesium-calcium alloy(ZQ).Scanning electron microscope(SEM) and X-ray diffraction(XRD) analysis confirm that the surface of the coating sample(ZQ-HEP) is composed of outer nano-sheet HA,middle flocculent-lamellae GO and inner Mg(OH)2 nano-sheet.The electrochemical corrosion resistance test in vitro shows that compared with the untreated ZQ,ZQ-HEP has higher corrosion resistance in phosphate buffer solution(PBS).A rabbit femoral condyle fracture model was constructed to evaluate the fracture repair effect of ZQ samples before and after surface modification.Postoperative gross observation,radiograph and histological analysis confirm that compared with the untreated ZQ,ZQ-HEP screws could decrease the hydrogen release obviously and thus the subcutaneous emphysema after implantation into the body.Meanwhile,due to its higher corrosion resistance and bioactivity,ZQ-HEP screw could maintain its integrity better than the ZQ one at 4 weeks postoperatively,and induce more new bone growth.Therefore,more rapid fracture healing is observed on ZQ-HEP than ZQ.In conclusion,the multi-functional coating construction strategy proposed in current study could have good prospect of clinical application.It can not only regulate the degradation rate of medical magnesium metals,but also significantly improve their osteogenic ability.更多还原