Novel Magnesium Alloys Developed for Biomedical Application: A Review Nan Li, Yufeng Zheng * State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China [Manuscript received November 11, 2012, in revised form December 25, 2012, Available online 9 February 2013] There is an increasing interest in the development of magnesium alloys both for industrial and biomedical applications. Industrial interest in magnesium alloys is based on strong demand of weight reduction of transportation vehicles for better fuel efficiency, so higher strength, and better ductility and corrosion resistance are required. Nevertheless, biomedical magnesium alloys require appropriate mechanical properties, suitable degradation rate in physiological environment, and what is most important, biosafety to human body. Rather than simply apply commercial magnesium alloys to biomedical field, new alloys should be designed from the point of view of nutriology and toxicology. This article provides a review of state-of-the-art of magnesium alloy implants and devices for orthopedic, cardiovascular and tissue engineering applications. Advances in new alloy design, novel structure design and surface modification are overviewed. The factors that influence the corrosion behavior of magnesium alloys are discussed and the strategy in the future development of biomedical magnesium alloys is proposed. KEY WORDS: Biomaterials; Magnesium alloys; Biodegradation; Mechanical property; Biocompatibility 1. Introduction Magnesium alloys for biomedical applications are in spotlight recently. They have advantages over traditional metallic mate- rials, ceramics and biodegradable polymers. For mechanical properties, metals are more suitable for load-bearing applications compared with ceramics or polymer because of their high me- chanical strength as well as high fracture toughness. The den- sities of magnesium (1.738 g/cm 3 ) and magnesium alloys (1.75e 1.85 g/cm 3 ) are very similar to that of human cortical bone (1.75 g/cm 3 ), while the density of biomedical titanium alloy Ti6Al4V is 4.47 g/cm 3[1] . For biocompatibility, magnesium ions are present in large amount in the human body and involved in many metabolic reactions and biological mechanisms. The hu- man body usually contains magnesium approximately 35 g per 70 kg body weight and the daily demand for magnesium is about 375 mg [2] . Magnesium alloys are promising candidates for or- thopedic and cardiovascular implants and have attracted increasing attention since there is no requirement for a secondary removal surgery. Potential of commercial magnesium alloys as biodegradable implant materials were evaluated. Witte et al. [3] investigated in vivo corrosion of 4 magnesium alloys and found that the corrosion layer of all the alloys displayed an accumulation of biological calcium phosphates and all alloys increased the newly formed bone compared to the polymer. According to this study, LAE442 exhibited the lowest corrosion rate, while AZ31, AZ91 and WE43 were found to degrade at similar rates [3] . Gao et al. [4] reported that ZK60 alloy lost 3.1% of its original mass after Prof. Yufeng Zheng’ s research is concerned with development of new kind of biomedical metallic materials, including biodegradable magnesium alloys and iron-based alloys, b-Ti alloys with low elastic modulus, nickel-free Ti-based shape memory alloys, nanocrystalline metals and alloys and bulk metallic glasses, and their medical devices in dentistry, or- thopedics and interventional therapy. He has published over 230 SCI journal papers since 1998, with the citation of over 3100 times and h-index of 26. He edited 7 books and book chapters, and owned 27 Chinese Invention Patents. He was granted with over 30 projects including the National Basic Research Program of China and the National Science Fund for Distinguished Young Scholars. He served as a member of the editorial board of Journal of Biomedical Materials Research Part B-Applied Biomaterials (Wiley), the associate editor board of Materials Letters (Elsevier), the editor board of Journal of Materials Science & Technology (Elsevier) and Acta Metallurgica Sinica (English Letters) (Springer). * Corresponding author. Prof., Ph.D.; Tel./Fax: þ86 10 62767411; E-mail address: yfzheng@pku.edu.cn (Y. Zheng). 1005-0302/$ e see front matter Copyright Ó 2013, The editorial office of Journal of Materials Science & Technology. Published by Elsevier Limited. All rights reserved. http://dx.doi.org/10.1016/j.jmst.2013.02.005 Available online at SciVerse ScienceDirect J. Mater. Sci. Technol., 2013, 29(6), 489e502