Design of magnesium alloys with controllable degradation for biomedical implants: From bulk to surface.
The combination of high strength, light weight, and natural biodegradability renders magnesium (Mg)-based alloys promising in orthopedic implants and cardiovascular stents. Being metallic materials, Mg and Mg alloys made for scaffolds provide the necessary mechanical support for tissue healing and cell growth in the early stage, while natural degradation and reabsorption by surrounding tissues in the later stage make an unnecessarily follow-up removal surgery. However, uncontrolled degradation may collapse the scaffolds resulting in premature implant failure, and there has been much research in controlling the degradation rates of Mg alloys. This paper reviews recent progress in the design of novel Mg alloys, surface modification and corrosion mechanisms under different conditions, and describes the effects of the structure, composition, and surface conditions on the degradation behavior in vitro and in vivo.



Owing to their unique mechanical properties, biodegradability, biocompatibility, Mg based biomaterials are becoming the most promising substitutes for tissue regeneration for impaired bone, vascular and other tissues because these scaffolds can provide not only ideal space for the growth and differentiation of seeded cells but also enough strength before the formation of normal tissues. The most important is that these scaffolds can be fully degraded after tissue regeneration, which can satisfy the increasing demand for better biomedical devices and functional tissue engineering biomaterials in the world. However, the rapid degradation rate of these scaffolds restricts the wide application in clinic. This paper reviews recent progress on how to control the degrdation rate based on the relevant corrosion mechanisms through the design of porous structure, phase structure, grains, and amorphous structure as well as surface modification, which will be beneficial to the better understanding and functional design of Mg-based scaffolds for wide clinical applications in tissue reconstruction in near futures.
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Faculty of Materials Science & Engineering, Hubei University, Wuhan 430062, China.
Xia
X
Li
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Faculty of Materials Science & Engineering, Hubei University, Wuhan 430062, China. Electronic address: liuxiangmei1978@163.com.
Xiangmei
X
Liu
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Faculty of Materials Science & Engineering, Hubei University, Wuhan 430062, China. Electronic address: shuilin.wu@hubu.edu.cn.
Shuilin
S
Wu
Division of Spine Surgery, Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
K W K
KWK
Yeung
State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
Yufeng
Y
Zheng
Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China. Electronic address: paul.chu@cityu.edu.hk.
Paul K
PK
Chu
D000497:Alloys / Q000494:pharmacology*; D000818:Animals; D003343:Corrosion; D006801:Humans; D008274:Magnesium / Q000494:pharmacology*; D019736:Prostheses and Implants; D011474:Prosthesis Design; D013499:Surface Properties
D000497:Alloys; D008274:Magnesium
Biodegradability; Corrosion; Implants; Magnesium alloys; Surface modification