Department of Bioengineering, University of California at Riverside, Riverside, California 92521, USA.
J Biomed Mater Res A. 2011 Nov;99(2):249-60. doi: 10.1002/jbm.a.33188. Epub 2011 Aug 16.
A novel class of biodegradable metals, magnesium (Mg) and Mg-based alloys, has recently attracted much attention because of unique biodegradation and mechanical properties for medical applications. Ideally, Mg-based devices should degrade no faster than the degradation products can be eliminated efficiently from the body. Additionally, for orthopedic and maxillofacial applications, the implant integration with the surrounding bone is critical for its clinical success. Therefore, it is necessary to thoroughly characterize Mg surface and degradation and investigate how these characteristics influence its interactions with essential cells, for example, bone marrow derived mesenchymal stem cells. The objectives of this study were to investigate (1) the effects of two surface conditions (the presence vs. absence of surface oxides) on Mg degradation and mesenchymal stem cell adhesion, and (2) the effects of two essential aqueous environments (the presence vs. absence of physiological ions and proteins) on Mg degradation. In an effort towards standardizing testing methods for Mg alloys, consistent and well-controlled experimental methods were designed to characterize the surface and degradation of Mg and its interactions with cells. The results demonstrated that original surface (oxidized vs. polished) conditions had a less pronounced effect on regulating initial cell adhesion, but did affect surface morphology and composition of the Mg samples after 24 h of cell culture. The presence versus absence of biological ions and proteins had a significant effect on Mg degradation mode and rate. In conclusion, the material surface and anatomical sites of implantation dependent on the intended applications must be carefully considered while assessing Mg alloys in vitro or in vivo for medical applications. Standardized testing procedures and methods are critically needed for developing more effective medical-grade Mg alloys.
一种新型可生物降解金属，镁 (Mg) 和 Mg 基合金，由于其独特的生物降解和机械性能，最近引起了人们的广泛关注，可用于医学应用。理想情况下，Mg 基器械的降解速度不应快于降解产物从体内有效消除的速度。此外，对于骨科和颌面应用，植入物与周围骨骼的整合对于其临床成功至关重要。因此，有必要彻底表征 Mg 表面和降解情况，并研究这些特性如何影响其与基本细胞（例如骨髓间充质干细胞）的相互作用。本研究的目的是研究 (1) 两种表面状态（存在表面氧化物与不存在表面氧化物）对 Mg 降解和间充质干细胞黏附的影响，以及 (2) 两种必需水相环境（存在生理离子和蛋白质与不存在生理离子和蛋白质）对 Mg 降解的影响。为了标准化 Mg 合金的测试方法，设计了一致且受控的实验方法来表征 Mg 的表面和降解情况及其与细胞的相互作用。结果表明，原始表面（氧化与抛光）条件对调节初始细胞黏附的影响较小，但确实会影响细胞培养 24 小时后 Mg 样品的表面形貌和组成。生物离子和蛋白质的存在与否对 Mg 的降解模式和速率有显著影响。总之，在评估 Mg 合金的体外或体内医学应用时，必须根据预期应用仔细考虑材料表面和植入部位。需要标准化的测试程序和方法来开发更有效的医用级 Mg 合金。
