Indirectly extruded biodegradable Zn-0.05wt%Mg alloy with improved strength and ductility： In vitro and in vivo studies  

作　　者：Chi Xiao Liqing Wang Yuping Ren Shineng Sun Erlin Zhang Chongnan Yan Qi Liu Xiaogang Sun Fenyong Shou Jingzhu Duan Huang Wang Gaowu Qin 

机构地区：[1]Department of Spine Surgery, Shengjing Hospital of China Medical University. Shenyang 110004, China [2]Key LaboratoryforAnisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering. Northeastern University,Shenyang 110819, China [3]Department of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian 116001, China

出　　处：《Journal of Materials Science & Technology》2018年第9期1618-1627,共10页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 51525101 and 81271995);Fundamental Research Funds for the Central Universities (No. N141008001)

摘　　要：As compared to permanent orthopedic implants for load-bearing applications, biodegradable orthopedic implants have the advantage of no need for removing after healing, but they suffer from the ＂trilemma＂ problem of compromising among sufficiently high mechanical properties, good biocompatibility and proper degradation rate conforming to the growth rate of new bones. In the present work, in vitro and in vivo studies of a Zn-0.05 wt%Mg alloy（namely, Zn-0.05 Mg alloy） were conducted with pure Zn as a control. The Zn-0.05 Mg alloy is composed of a small amount of Mg2 Zn11 phase embedded in the refined Zn matrix with an average grain size of ～20 μm. The addition of 0.05 wt% Mg into Zn significantly increases the ultimate tensile strength up to 225 MPa and the elongation to fracture to 26%, but has little influence on the in vitro degradation rate. Both Zn and Zn-0.05 Mg alloy exhibit homogeneous in vitro degradation with a rate of about 0.15 mm/year. Based on the cytotoxicity evaluation, Zn and Zn-0.05 Mg alloy do not induce toxicity to L-929 cells, indicating that they have little toxicity to the general functions of the animal. An in vivo biocompatibility study of Zn and Zn-0.05 Mg alloy samples by placing them in a rabbit model for 4.12 and 24 weeks, respectively did not show any inflammatory cells, and demonstrated that new bone tissue formed at the bone/implant interface, suggesting that Zn and Zn-0.05 Mg alloy promote the formation of new bone tissue. The in vivo degradation of Zn and Zn-0.05 Mg alloy does not bring harm to the important organs and their cell structures. More interestingly, Zn and Zn-0.05 Mg alloy exhibit strong antibacterial activity against Escherichia coli and Staphylococcus aureus. The above results clearly demonstrate that the Zn-0.05 Mg alloy could be a potential biodegradable orthopedic implant material.As compared to permanent orthopedic implants for load-bearing applications, biodegradable orthopedic implants have the advantage of no need for removing after healing, but they suffer from the ＂trilemma＂ problem of compromising among sufficiently high mechanical properties, good biocompatibility and proper degradation rate conforming to the growth rate of new bones. In the present work, in vitro and in vivo studies of a Zn-0.05 wt%Mg alloy（namely, Zn-0.05 Mg alloy） were conducted with pure Zn as a control. The Zn-0.05 Mg alloy is composed of a small amount of Mg2 Zn11 phase embedded in the refined Zn matrix with an average grain size of ～20 μm. The addition of 0.05 wt% Mg into Zn significantly increases the ultimate tensile strength up to 225 MPa and the elongation to fracture to 26%, but has little influence on the in vitro degradation rate. Both Zn and Zn-0.05 Mg alloy exhibit homogeneous in vitro degradation with a rate of about 0.15 mm/year. Based on the cytotoxicity evaluation, Zn and Zn-0.05 Mg alloy do not induce toxicity to L-929 cells, indicating that they have little toxicity to the general functions of the animal. An in vivo biocompatibility study of Zn and Zn-0.05 Mg alloy samples by placing them in a rabbit model for 4.12 and 24 weeks, respectively did not show any inflammatory cells, and demonstrated that new bone tissue formed at the bone/implant interface, suggesting that Zn and Zn-0.05 Mg alloy promote the formation of new bone tissue. The in vivo degradation of Zn and Zn-0.05 Mg alloy does not bring harm to the important organs and their cell structures. More interestingly, Zn and Zn-0.05 Mg alloy exhibit strong antibacterial activity against Escherichia coli and Staphylococcus aureus. The above results clearly demonstrate that the Zn-0.05 Mg alloy could be a potential biodegradable orthopedic implant material.

关 键 词：Zn-Mg alloy Mechanical properties BIODEGRADABILITY BIOCOMPATIBILITY Antibacterial activity 

分 类 号：TB2[一般工业技术—工程设计测绘]