医用镁钙合金植酸钠氧化膜的制备及其生物相容性研究

Magnesium alloys have been one of the hot topics in the field of degradable biomaterials due to their many advantages, such as low elastic modulus, similar density to natural bone and in vivo degradation via corrosion. However, the too rapid degradation rate of magnesium alloys in body fluids restricts their clinical applications. Micro arc oxidation (MAO) can effectively improve the corrosion resistance and biocompatibility of magnesium alloys. In view of good bioactivity, calcium phosphate compounds are widely used as biomaterials but the corrosion resistance of anodic coatings obtained by MAO in the solution containing inorganic phosphate is not ideal. Based on our previous research results, sodium phytate, a food additive, and calcium-containing materials are chosen as the main electrolytes in the project. Anodic coatings with high corrosion resistance, antibacterial property and containing magnesium calcium phytate materials, which are similar to the iorganic salts of organism bones are developed on magnesium-calcium alloys. The influences of the processing parameters on the coating property and the degradable behavior of anodic coatings in simulated fluids will be studied. In addition, in vivo degradation regularity and bioactivity of the anodized Mg-Ca alloys by MAO will be explored by the animal implant experiments. The research achievement will clarify the mechanism of calcium ions taking part in the coating formation, reveal the structure change and the corrosion degradation regularity of anodic coatings in vitro and in vivo, establish the theoretical model about in vivo degradation of the anodized magnesium-calcium alloys and new bone development and discuss the possibility of sodium phytate anodic coatings used as the implant material, which will provide the important theoretical foundation and experimental data for the applications of magnesium alloys in the biomaterial area.

镁合金具有弹性模量低、密度与人骨接近以及可体内降解等优点，成为可降解生物材料研究的热点，但其在体液中腐蚀降解速度过快，制约了临床应用。微弧氧化能有效提高镁合金的耐蚀性和生物相容性。针对钙磷盐具有良好生物活性，但在无机磷酸盐中制备的氧化膜耐蚀性不够理想的现状，本项目在前期研究成果基础上，以食品添加剂植酸钠和钙盐为主要组分，在镁钙合金表面制备耐蚀性高、具有杀菌功能、含有与机体骨无机盐成分类似的植酸钙镁类物质的氧化膜。拟开展工艺参数对氧化膜性能影响以及氧化膜在模拟体液中降解行为的研究，并采用动物体内植入试验，探究氧化后的镁钙合金体内降解规律和生物活性。研究成果有望清晰钙离子参与氧化膜形成的机制，揭示氧化膜体外、体内组织演化与腐蚀降解规律，建立微弧氧化后的镁钙合金体内降解和新骨生长模型，并探讨其作为人体植入材料的可行性，为镁合金在生物材料领域的应用提供重要的理论基础和实验依据。

镁合金具有弹性模量低、密度与人骨接近以及可体内降解等优点，成为可降解生物材料研究的热点，但其在体液中腐蚀降解速度过快，制约了临床应用。微弧氧化能有效提高镁合金的耐蚀性和生物相容性。针对钙磷盐具有良好生物活性，但在无机磷酸盐中制备的氧化膜耐蚀性不够理想的现状，本项目在前期研究成果基础上，以食品添加剂植酸钠和钙盐为主要组分，在镁钙合金表面制备耐蚀性高、具有良好生物相容性的微弧氧化膜。开展工艺参数对氧化膜性能影响以及氧化膜在模拟体液中降解行为的研究，探究氧化后的镁钙合金降解规律和体外生物活性。采用超高效液相色谱串联时间质谱法（LC-QTOF-Ms）研究微弧氧化时植酸钠的水解规律。结果表明，在含氢氧化钠和植酸钠溶液中制备的氧化样品对L-929细胞不会产生毒性，满足用作生物材料要求。在0-6 g/L范围内，植酸钠有助于提高氧化膜的耐蚀性和钙含量。随浸泡时间延长，氧化膜中的钙和磷含量增加，表现出良好的体外生物活性。在微弧氧化过程中，由于火花放电导致植酸钠裂解，生成低级磷酸肌醇酯和无机磷酸物。研究成果有望清晰钙离子参与氧化膜形成的机制，揭示氧化膜体外、体内组织演化与腐蚀降解规律，建立微弧氧化后的镁钙合金体内降解和新骨生长模型，并探讨其作为人体植入材料的可行性，为镁合金在生物材料领域的应用提供重要的理论基础和实验依据。