2024 Fiscal Year Final Research Report

Development of a new evaluation method for corrosion properties of biodegradable metals for the risk assessment in their efficacy and safety as medical devices

Research Project

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Project/Area Number	23K25242
Project/Area Number (Other)	22H03988 (2022-2023)
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Multi-year Fund (2024) Single-year Grants (2022-2023)
Section	一般
Review Section	Basic Section 90140:Medical technology assessment-related
Research Institution	National Institute for Materials Science
Principal Investigator	Yamamoto Akiko 国立研究開発法人物質・材料研究機構, 高分子・バイオ材料研究センター, 上席研究員 (20343882)
Co-Investigator(Kenkyū-buntansha)	今井啓道東北大学, 医学系研究科, 教授 (80323012) 清水良央東北大学, 医学系研究科, 大学院非常勤講師 (30302152)
Project Period (FY)	2024-04-01 – 2025-03-31
Keywords	レギュラトリーサイエンス / 生体吸収性金属材料 / 炎症反応 / インピーダンス / 疑似組織
Outline of Final Research Achievements	Success in biomedical application of biodegradable metals depends on their corrosion/degradation rates in patient bodies. It is necessary to appropriately evaluate corrosion properties of biodegradable metals for reduction of risks in their clinical application. Therefore, we developed new in vitro evaluation methods for biodegradable metals considering blood flow and inflammation as influencing factors of their corrosion properties in patient bodies. In order to simulate the difference in blood flow inside the tissue, we employed model tissues with different ion and gas diffusion rates. Electrochemical impedance spectroscopy revealed the decrease of corrosion rate in the model tissue. For the recreation of the inflammation in the tissue, we employed macrophages with different activation levels. The electrochemical impedance spectroscopy with hyper-activated macrophages demonstrated acceleration in corrosion rate of AZ31 alloy.
Free Research Field	生体材料学
Academic Significance and Societal Importance of the Research Achievements	ステントや骨接合材は損傷部位の修復後には不要になるが、現行の非吸収性デバイスの除去には再手術が必要であり、患者の肉体的・金銭的負担であった。生体内分解性金属材料デバイスの実用化は、これらの負担の解消に有用である。本研究で開発した血流量・炎症反応を模擬した評価法は、生体内分解性金属材料の患者体内における腐食挙動の理解に繋がり、臨床使用時のリスク評価ならびにデバイス開発・実用化に資する。材料の生体内腐食特性評価において、組織中物質拡散速度を考慮した例はない。また免疫細胞の活性化による生体分解性金属材料の腐食挙動を明らかにした例もなく、いずれも貴重な成果であり学術的意義が高い。