Influences of Extrusion and Silver Content on the Degradation of Mg-Ag Alloys In Vitro and In Vivo

Guanqi Liu; Jianmin Han; Xiaodong Yu; Shenpo Yuan; Zhihua Nie; Tiancheng Qiu; Ziyu Yan; Chengwen Tan; Chuanbin Guo

doi:10.1155/2022/2557518

Influences of Extrusion and Silver Content on the Degradation of Mg-Ag Alloys In Vitro and In Vivo

Bioinorg Chem Appl. 2022 Apr 23:2022:2557518. doi: 10.1155/2022/2557518. eCollection 2022.

Authors

Guanqi Liu^{1

2}, Jianmin Han², Xiaodong Yu¹, Shenpo Yuan², Zhihua Nie¹, Tiancheng Qiu³, Ziyu Yan³, Chengwen Tan¹, Chuanbin Guo³

Affiliations

¹ School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
² Department of Dental Materials, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing 100081, China.
³ Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing 100081, China.

Abstract

Binary magnesium-silver (Mg-Ag) alloys were designed as antibacterial materials for biomedical implant applications. In the present study, we focused on the effects of extrusion (extrusion ratio (ER): 1, 7.1, and 72.2) and Ag content (Ag = 0, 3, and 6 wt.%) on the degradation of Mg-Ag alloys in vitro and in vivo via microstructure characterization and corrosion/degradation measurements. The results showed that the Ag promoted a galvanic reaction with the Mg matrix to accelerate degradation or formed a protective oxide mesh texture to inhibit degradation, especially in vivo. Ag might also be beneficial for product crystallization, biomineralization, and organic matter deposition. For pure Mg, extrusion produced a more refined grain and decreased the degradation rate. For the Mg-Ag alloys, a low extrusion ratio (7.1) accelerated the degradation caused by the increase in the proportion of the precipitate. This promoted the release of Mg²⁺ and Ag⁺, which led to more deposition of organic matter and calcium phosphate, but also more H₂ bubbles, which led to disturbance of product deposition in some local positions or even inflammatory reactions. Extrusion at a higher ratio (72.2) dissolved the precipitates. This resulted in moderate degradation rates and less gas production, which promoted osteogenesis without an obvious inflammation reaction.