Elucidation of the absorption mechanism of magnesium alloys in bone marrow and exploration of their optimization as bone fracture treatment devices

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K09261
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56020:Orthopedics-related
• Research Institution: Fujita Health University
• Principal Investigator: Kawano Yusuke 藤田医科大学, 医学部, 准教授 (50528560)
• Co-Investigator(Kenkyū-buntansha): 清水 一郎 岡山理科大学, 工学部, 教授 (10263625) ; 新留 琢郎 熊本大学, 大学院先端科学研究部(工), 教授 (20264210)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: マグネシウム合金

Outline of Final Research Achievements

Bioresorbable magnesium (Mg) alloy-based implants offer promising alternatives to traditional metallic implants for the treatment of bone fractures because they eliminate the need for implant removal after healing. The Mg-Y-rare-earth (RE)-Zr alloy WE43, designed for orthopedic implants, has received European Conformity mark approval. However, currently, WE43 is not clinically used in certain countries possibly because of concerns related to RE metals. In this study, we investigated the use of a RE-free alloy, namely, Mg-Zn-Zr alloy (ZK30), as an implant for bone fractures. Hydrofluoric acid (HF) treatment was performed to improve the corrosion resistance of ZK30. HF-treated ZK30 (HF-ZK30) exhibited lower corrosion rate and higher biocompatibility than those of WE43 in in vitro experiments. After implanting a rod of HF-ZK30 into the fractured femoral bones of mice, HF-ZK30 held the bones and healed the fracture without deformation.

Free Research Field

バイオマテリアル

Academic Significance and Societal Importance of the Research Achievements

マグネシウム合金の力学的な強度を増強させるために、レアアースを用いることは海外においてよく行われる。しかし日本ではレアアースを含む金属を体内に留置することは、その安全性に懸念があるため現状では認められていない。その点、我々が研究で立証したフッ化処理したZK30は、レアアースを用いることなくWE43と少なくとも同等程度の強度を有する事ができ、今後の医療において重要な意義を見出したと考えられる。