医用Mg-Li-Ca合金腐蚀、表面改性及生物相容性研究进展

自Frank Witte发现LAE442（Mg-4Li-4Al-2RE）具有优异的在体耐蚀性能以来，Mg-Li合金的生物医用研究在德国受到特别关注。

我们课题组率先在国际上开展医用Mg-Li-Ca合金腐蚀机理、表面改性和生物相容性研究。有关进展情况简要介绍如下：  

（一） 腐蚀机理  

工作比较了Mg-Li-Ca合金与Mg-Ca合金耐蚀性能，研究了Mg-Li-Ca-(Y)合金腐蚀机理，论文发表在《金属学报》（2011）、《Corrosion Science》（2014）和《Progress in Natural Science: Materials International》（2014）。尤其是，2014年在《Corrosion Science》发表的双相Mg-Li-Ca合金腐蚀工作论文获得广泛关注，已被EIS高引。

（二）表面改性

研究了Mg-Li-Ca-(Y)表面Ca-P涂层、Zn-Ca-P涂层和阳极氧化膜/聚乳酸复合膜，工作陆续发表在《重庆理工大学学报》（校庆专刊）（2010）、《Trans. Nonferrous Met. Soc. China》（2013）和《Frontiers of Materials Science》（2014）。

 （三）生物相容性

Zn-Ca-P涂层血液相容性发表在《Frontiers of Materials Science》（2016）；

与青岛大学、北京大学合作研究工作，涉及MAO/PLA复合涂层血液相容性和细胞相容性研究，论文发表在《 中国组织工程研究》（2014）。最新工作发表在生物材料权威刊物《ACS Appl. Mater. Interfaces》（2016）。

Title: In Vitro Corrosion and Cytocompatibility of a Microarc Oxidation Coating and Poly(L-lactic acid) Composite Coating on Mg-1Li-1Ca Alloy for Orthopaedic Implants  

Abstract

Manipulating the degradation rate of biomedical magnesium alloys poses a challenge. The characteristics of a micro-arc oxidation (MAO), prepared in phytic acid, and poly (L-lactic acid) (PLLA) composite coating, fabricated on a novel Mg-1Li-1Ca alloy, were investigated through field emission scanning electron microscopy (FE-SEM), electron probe X-ray microanalysis (EPMA), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The corrosion behaviours of the samples were evaluated via hydrogen evolution, potentiodynamic polarization and electrochemical impedance spectroscopy in Hanks’ solution. The results indicated that the MAO/PLLA composite coatings significantly enhanced the corrosion resistance of the Mg-1Li-1Ca alloy. MTT and ALP assays using MC3T3 osteoblasts indicated that the MAO/PLLA coatings greatly improved the cytocompatibility, and the morphology of the cells cultured on different samples exhibited good adhesion. Haemolysis tests showed that the composite coatings endowed the Mg-1Li-1Ca alloys with a low haemolysis ratio. The increased solution pH resulting from the corrosion of magnesium could be tailored by the degradation of PLLA. The degradation mechanism of the composite coatings was discussed. The MAO/PLLA composite coating may be appropriate for applications on degradable Mg-based orthopaedic implants.

图1 Mg-1Li-1Ca合金表面MAO（阳极氧化膜）/PLLA（聚乳酸）复合涂层降解机理示意图

相关论文及发明专利：

[1]     医用Mg-Li-Ca合金表面Ca-P涂层腐蚀研究,重庆理工大学学报(自然科学版)（校庆专刊）,2010, 24(10): 34-39

[2]     医用Mg-Ca和Mg-Li-Ca合金腐蚀研究，金属学报，2011, 47(11): 1477-1482.

[3]      医用新型Mg-Li-Ca合金材料体外生物相容性及生物活性评价. 中国组织工程研究. 2014, 18(52):8409-13.

[4]      Influence of solution temperatureon corrosion resistance of Zn-Ca phosphateconversion coating on biomedical Mg-Li-Ca alloys, Trans. NonferrousMet. Soc. China, 23(11), 2013: 3293- 3299.

[5]      Corrosion andcharacterisation of dual phase Mg-Li-Ca alloy in Hank’s solution:the influence of microstructural features. Corrosion Science,79, 2014: 69-82.

[6]     In vitro corrosion of Mg–1.21Li–1.12Ca-1Y alloy. Progress in Natural Science:  Materials International, 24(5), 2014: 492–499.

[7]      In vitro degradation of MAO/PLA coating on Mg-1.21Li-1.12Ca-1.0Y alloy. Frontiers of Materials Science, 2014. 8(4): 343-353.

[8]      In Vitro Corrosion and Cytocompatibility of a Microarc Oxidation Coating and Poly(L-lactic acid) Composite Coating on Mg-1Li-1Ca Alloy for Orthopaedic Implants,ACS Appl.Mater. Interfaces, 2016, DOI: 10.1021/acsami.6b00527.

[9] Blood compatibility of zinc–calcium phosphate conversion coating on Mg–1.33Li–0.6Ca alloy, Frontiers of Materials Science, 2016, 10(3): 281–289.

[10]  医用镁合金表面植酸微弧阳极氧化膜及聚乳酸涂层及工艺，发明专利，201210184704.X.（已授权）