水熱合成鍶取代型氫氧基磷灰石鍍層改善生物可降解性AZ91鎂合金在模擬體液之抗腐蝕效應研究

Hydrothermally Synthesized Sr-substituted Hydroxyapatite Coating to Improve the Corrosion Performances of Biodegradable AZ91 Magnesium Alloy in Simulated Body Fluid

梁哲嘉(Zhe-Jia Liang)

指導教授 ： 楊崇煒

國立虎尾科技大學/工程學院/材料科學與工程系材料科學與綠色能源工程碩士班/碩士(2017年)

摘要

目前生物可降解性鎂合金是相當受到矚目的新一代輕量化生醫金屬材料，其彈性模數、生物相容性與人體的皮質骨相當接近，可作為體內可降解之生醫植入材料。然而由於鎂合金活性大，在生理環境溶液下容易腐蝕，因此控制鎂合金的降解速率是發展鎂合金作為生醫材料的關鍵。氫氧基磷灰石(HA)生物活性陶瓷具有良好生物相容性、生物活性、引導骨生成能力，本研究基於以HA作為表面鍍層可有效減少鎂合金腐蝕速率的概念下，藉由水熱法在175ºC下反應2小時，直接合成Mg(OH)2、HA及摻雜不同含量Sr2+之SrHA鍍層並析鍍於AZ91鎂合金表面，並比較被覆Mg(OH)2、HA及SrHA鍍層改善AZ91鎂合金之抗腐蝕性與細胞反應性。利用X光繞射分析鍍層相組成、以掃描式電子顯微鏡來觀察微觀組織，在模擬體液環境下浸泡32天後發現HA及SrHA仍有保護AZ91鎂合金的特性，鍍層結構也還相當完整，而電化學腐蝕的分析則使用動電位極化曲線測試以及交流阻抗頻譜測試對鍍層進行分析，此外亦藉由體外細胞培養試驗評估細胞在SrHA鍍層的存活率，以及在披覆SrHA鍍層之表面之貼附情形。

關鍵字

水熱法 ； 氫氧基磷灰石 ； 鎂合金 ； 動電位極化曲線 ； 交流阻抗

並列摘要

Biodegradable magnesium (Mg) and its alloys are new generational and the state-of-art light-weight metallic biomaterials of nowadays. The elastic modulus of Mg alloys is close to that of the human cortical bones, and they can be used for hard tissues implantation because of their good biocompatibility in the human body. However, the extensive applications of Mg alloys are limited mainly by their high corrosion rate in physiological environments. Therefore, the important factor to develop biological magnesium implants is to decrease their degradation rate. In order to improve the corrosion resistance and biocompatibility of biomedical magnesium, Sr ions are doped in hydroxyapatite (HA) to form Sr-substituted (Sr-HA) surface coatings on the AZ91 Mg alloy by the hydrothermal synthesizing process under the condition of heating at 175°C, held for 2 h. The purpose of this study is to study the effect of Mg(OH)2, HA and various Sr-HA surface coatings on improving the anti-corrosion performances of AZ91 Mg substrate within the simulated body fluid (SBF). Experimental evidence confirmed that Mg(OH)2, HA and Sr-HA coatings can be uniformly deposited without rupture on the entire surface of AZ91 Mg alloy by the hydrothermal synthesizing process. Potentiodynamic polarization and immersion tests in the Kokubo’s SBF show that the corrosion resistance of AZ91 is significantly improved, and the dissolution rate is decreased with the deposition of hydrothermal Sr-HA coatings. The in vitro cell culture studies, using human osteosarcoma MG63 osteoblast-like cell, demonstrated that cell viability on the surface of Sr-HA-coated AZ91 Mg alloy after 6 to 48 h cell culture. The results suggest that the hydrothermally synthesized Sr-HA coating is effective to improve the in vitro biocompatibility of the Mg-based alloys.

並列關鍵字

Hydrothermally ； Hydroxyapatite ； Magnesium Alloy ； Potentiodynamic polarization curve ； Electrochemical impedance spectroscopy, EIS

參考文獻

[6] M. P. Staiger, A. M. Pietak, J. Huadmai , and G. Dias, (2006) ,“Magnesium and its alloys as orthopedic biomaterials: A review”, Biomaterials, 27, 1728-1734.

[7] L. Hench, J. M. Polak, (2002), “Third-generation biomedical materials”, Science, 295, 1014-1017.

[8] H. Waizy, J. M. Seitz, J. Reifenrath, A. Weizbauer, (2013) ,“Biodegradable magnesium implant for orthopedic applications”, J. Mater. Sci, 48, 39-50.

[9] Y. Chen, Z . Xu, C . Smith, and J. Sankar, (2014) ,“Recent advanvces om the development of magnesium alloys for biodegrasable implants”,Acta Biomater,10, 4561-4573.

[11] Y. Song, E. Han, D. Shan, C. Yim, B. You, (2012), “The effect of Zn concentration on the corrosion behavior of Mg–xZn alloys” Corros. Sci, 65, 322-330.