HOME > Profile > YAMAMOTO, Akiko
- Address
- 305-0044 1-1 Namiki Tsukuba Ibaraki JAPAN [Access]
Accepting Students
Research
- Keywords
Biomaterials, Biocompatibility, Biodegradation, in vitro evaluation
For biomedical application, it is important to evaluate materials' functionality as well as biological safety. Most of the materials degrade inside the body, it is also important to investigate materials degradation behavior in the physiological environment. These properties of conventional medical materials were evaluated by in vivo animal tests, however their tests results often disagree with those of clinical trials. Furthermore, recent global movement concerning animal welfare limits the execution of animal tests. Therefore, we are challenging the development of new evaluation method by simulating physiological environment in vitro, which will contribute to more quick and efficient development of new medical devices.
Gas cavity formation behavior of a Mg-alloy screw was examined using our original evaluation method; model tissue system. The polymer coating suppressed corrosion reaction of the substrate, reducing the gas cavity volume formed in the model tissue, which is quantified by micro-X-ray CT analysis.
PublicationsNIMS affiliated publications since 2004.
Research papers
- YAMAMOTO, Akiko, KIKUCHI, Masanori, SUETSUGU, Yasushi. Enhancement of Copper Antiviral Activity with Glutathione Treatment. ACS Applied Bio Materials. 9 [12] (2026) 5237-5248 10.1021/acsabm.6c00520 Open Access
- Akiko Yamamoto, Yuki Ito. Effect of Humidity on Antibacterial Activity of Copper and Its Alloy Surfaces. MATERIALS TRANSACTIONS. 67 [1] (2026) MT-M2025099 10.2320/matertrans.mt-m2025099 Open Access
- Manas Ranjan Sahu, Akiko Yamamoto. Investigating the Effect of Thickener Concentrations on the Corrosion Behavior of Pure Mg. Journal of Biomedical Materials Research Part A. 113 [2] (2025) e37878 10.1002/jbm.a.37878 Open Access
Books
- 山本 玲子. 生体吸収性金属材料の分解特性評価技術（第2章10節）. 界面制御による革新的生体適合性材料開発. 株式会社エヌ・ティー・エス, 2025, 10.
- 山本 玲子. 第6章 マグネシウム合金の生体内分解特性と高分子被覆による制御. 株式会社シーエムシー出版, 2019
- 山本 玲子. 金属材料の毒性と安全性・細胞による毒性評価法. 医療用金属材料概論. , 2010, 223-238.
Proceedings
- Zahiruddeen Salam Zahari, Dayangku Noorfazidah Awang Shri, Akiko Yamamoto. Investigation of mechanical properties and in vitro corrosion of bulk nanostructured metal produced by equal channel angular pressing. INTERNATIONAL CONFERENCE ON BIOENGINEERING AND TECHNOLOGY (IConBET2021). (2022) 10.1063/5.0078675
- YAMAMOTO, Akiko, KOHYAMA, Yuko. CYTOCOMPATIBILITY OF MG ALLOYS AND THE EFFECT OF CELLS ON THEIR DEGRADATION IN BIOLOGICAL ENVIRONMENT. Magnesium Technology 2014. (2014) 381-385
- WITECKA, Agnieszka, YAMAMOTO, Akiko, Wojciech Swieszkowski . Improvement of cytocompability of magnesium alloy ZM21 by surface modification. Improvement of cytocompability of magnesium alloy ZM21 by surface modification. (2014) 375-380
Presentations
- YAMAMOTO, Akiko. Development of New In Vitro Evaluation Methods for Biomedical Application of Biodegradable Metals. 16th ISAJ Annual Symposium 2025. 2025 Invited
- YAMAMOTO, Akiko, 津田 升子. Enhancement of Antiviral Activity of Copper and Its Alloys with an Oligopeptide. 12th World Biomaterials Congress (WBC 2024). 2024
- 山本 玲子. 医療用金属材料の基礎～研究の最前線. 第45回日本バイオマテリアル学会大会. 2023 Invited
Misc
- YAMAMOTO, Akiko. Biosafety of Ceramic Fibers---Mechanism of Pulmonary Toxicity and in Vivo / in Vitro Evaluation. Journal of the Technical Association of Refractories, Japan (TAIKABUTSU OVERSEAS). 43 [1] (2023) 9-18
- 山本 玲子. 抗菌材料の活性指標と核酸分解能評価. バムサジャーナル. 34 [3] (2022) 145-150
- 山本玲子. マグネシウム合金製医療用デバイスの臨床例からみた課題. アルトピア. [8] (2018) 9-14
Published patent applications
Society memberships
日本バイオマテリアル学会, 日本金属学会, 日本機械学会, 日本動物実験代替法学会
Research Center for Macromolecules and Biomaterials
Volume loss estimation of biodegradable metals based on microfocus X-ray CT images
Biodegradable metals, Biodegradation behavior, microfocus X-ray computed tomography, Peak fitting
Overview
For the success of biodegradable implants made of Mg, Zn, Fe and their alloys as biodegradable metals, it is important to control their degradation behavior under physiological environment. Degradation rate of metallic materials is typically determined by weight loss measurement; however, it is difficult to perform with small specimens such as fine wires due to the difficulty on specimen collection after corrosion tests and acid cleaning. Since X-ray CT technique is frequently employed for the observation of implanted specimens, it would be beneficial if the volume loss of small implants could be determined based on X-ray CT images. Therefore, we applied peak-fitting on calculation of specimen volume loss based on the histogram data of X-ray CT images. Peak-fitting method is able to determine the volume loss of Mg ally specimen separately from bone tissue or insoluble salt layers (formed accompanying to corrosion), thereby allowing a more accurate estimation of volume loss than the conventional midpoint method.
Novelty and originality
- First application of peak-fitting method on X-ray CT data analysis
- Enables detailed analysis (such as insoluble salt volume), contributing to the elucidation of degradation behavior and mechanism of biodegradable metals
- Enables appropriate estimation of bioabsorbable Mg-based scaffold degradation based on micro-focus X-ray CT data---indicating isotropic degradation of struts in porcine artery
Details
Fig.1 (left) shows examples of X-ray CT images and histograms of a Mg alloy sample after immersion into simulated body fluid. In the histogram, peaks corresponding to corrosion products were observed in addition to those for the specimen and the background (air). Fig.1 (right) presents a comparison between the remaining volume ratios obtained from weight loss measurement and those from CT images using both the standard (midpoint) and the peak-fitting methods. It confirms the higher correlation between the latter and the weight loss than that of the former.
Micro-focus X-ray CT images of Mg-based biodegradable scaffolds implanted in porcine coronary artery were shown in Fig.2 (left). We used the midpoint method and the peak-fitting method to analyze CT histogram data to obtain remaining volume ratio of the scaffolds (shown in Fig.2, right). The result by the latter method matches very well to the simulation data assuming isotropic degradation of the scaffold struts with 8.5% loss of the cross-section area at 28d.
Summary
-Evaluation of biocorrosion properties of biodegradable metals in simulated body fluid or model tissue.
-Estimation of degradation profile of Mg-based biodegradable scaffold based on X-ray CT data
-Contribution to acceleration in development of new medical materials/devices through the developed in vitro evaluation methods.
