In vitro and in vivo studies of Zn-Mn biodegradable metals designed for orthopedic applications

Bo Jia; Hongtao Yang; Yu Han; Zechuan Zhang; Xinhua Qu; Yifu Zhuang; Qiang Wu; Yufeng Zheng; Kerong Dai

doi:10.1016/j.actbio.2020.03.009

In vitro and in vivo studies of Zn-Mn biodegradable metals designed for orthopedic applications

Acta Biomater. 2020 May:108:358-372. doi: 10.1016/j.actbio.2020.03.009. Epub 2020 Mar 9.

Authors

Bo Jia¹, Hongtao Yang², Yu Han¹, Zechuan Zhang³, Xinhua Qu⁴, Yifu Zhuang¹, Qiang Wu¹, Yufeng Zheng⁵, Kerong Dai⁶

Affiliations

¹ Department of Orthopaedic Surgery, Shanghai Key Laboratory of Orthopaedic Implants, Shanghai Ninth People's Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 200011, PR China.
² Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, PR China; Department of Plastic & Reconstructive Surgery, The Ohio State University, Columbus, OH 43210, United States.
³ Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, PR China.
⁴ Department of Bone and Joint Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, PR China.
⁵ Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, PR China. Electronic address: yfzheng@pku.edu.cn.
⁶ Department of Orthopaedic Surgery, Shanghai Key Laboratory of Orthopaedic Implants, Shanghai Ninth People's Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 200011, PR China. Electronic address: krdai@163.com.

PMID: 32165194
DOI: 10.1016/j.actbio.2020.03.009

Abstract

In recent years, Zn-based materials provide a new option as biodegradable metals for orthopedic applications. To improve the low strength and brittle nature of pure Zn, small amounts of alloying element Mn (0.1, 0.4 and 0.8 wt.%) were added into Zn to fabricate binary Zn-Mn alloys. An extremely high elongation (83.96 ± 2.36%) was achieved in the resulting Zn-0.8 wt.%Mn alloy. Moreover, Zn-Mn alloys displayed significantly improved cytocompatibility as compared to pure Zn, according to cell proliferation and morphology analyses. More importantly, a significantly improved osteogenic activity was verified after adding Mn regarding ALP activity and osteogenic expression. Furthermore, Zn-0.8 wt.%Mn alloy scaffolds were implanted into the rat femoral condyle for repairing bone defects with pure Ti as control. Enhanced osteogenic activities were confirmed for Zn-0.8Mn alloy in contrast to pure Ti based on Micro-CT and histological results, and favorable in vivo biosafety of Zn-0.8Mn alloy was verified by H&E staining and blood tests. The exceptional mechanical performance and favorable osteogenic capability render Zn-Mn alloy a promising candidate material in the treatment of bone defects or fracture repair. STATEMENT OF SIGNIFICANCE: The element Mn, on the one hand, as an essential trace element in the human body, promotes cell proliferation, adhesion, spreading, and regulates bone metabolism; on the other hand, it could significantly improve the ductility of Zn alloys. Here, we systematically reported the biocompatibility and biofunctionality of binary biodegradable Zn-Mn alloys in the bone environment. The Zn-Mn alloys promoted MC3T3-E1 cell proliferation, adhesion, spreading, and osteogenic differentiation in vitro. Furthermore, a rat femoral condyle defect model was established; porous Zn-Mn alloy scaffolds were manufactured to repair the bone defects. Significant bone regenerations, considerable bone ingrowth, and desirable biosafety were confirmed in vivo. Therefore, biodegradable Zn-Mn with promising osteogenic properties may become new options for orthopedic implant materials.

Keywords: Biodegradable metal; Orthopedic implant; Osteogenesis; Zn-Mn alloy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Absorbable Implants*
Alloys / pharmacology
Animals
Biocompatible Materials / pharmacology
Materials Testing
Osteogenesis*
Rats
Zinc / pharmacology

Substances

Alloys
Biocompatible Materials
Zinc