Evaluation of magnetization dynamics in multicore magnetic nanoparticles for cancer theranostics

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02163
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 21030:Measurement engineering-related
• Research Institution: Shizuoka University
• Principal Investigator: Ota Satoshi 静岡大学, 工学部, 准教授 (30774749)
• Co-Investigator(Kenkyū-buntansha): 倉科 佑太 東京農工大学, 工学(系)研究科(研究院), 准教授 (40801535)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 磁性ナノ粒子 / 磁気緩和 / 磁気粒子イメージング / がん温熱治療

Outline of Final Research Achievements

With respect to magnetic nanoparticles of the nanoflower structure similar to the multicore structure, the magnetization dynamics in the single core particles included in the multicore structure was divided from the effective dynamics in the multicore structure.
By the pulsed magnetic field whose switching time was approximately 10 ns, the magnetization relaxation for 5 ms was observed. The magnetization in the nanoflower particles was compared to the single core particles whose diameter was similar to the effective diameter in the nanoflower particles. The measured Neel relaxation time indicates that the effective anisotropy constant in the nanoflower particles was significantly different from that in the single core particles.
The measurement system for magnetic nanoparticles internalized into living adherent cells was constructed. It is indicated that the magnetization was reduced by inhibiting particle physical rotation and the dipole interaction due to aggregation in cells.

Free Research Field

バイオ磁気工学

Academic Significance and Societal Importance of the Research Achievements

腫瘍に集積させた磁性ナノ粒子を可視化する磁気粒子イメージングやがん温熱治療が注目されている。粒子が単体で応答するシングルコア構造に対して、複数のコア粒子が集合して実効的に単一粒子として機能するマルチコア構造が、診断治療に有効であるが、その磁化応答が未解明なため、診断治療の実用化に十分な磁気信号と発熱量が得られていない。
粒径などの粒子パラメータと磁化応答の相関性を体系化し、マルチコア構造のコア粒子間相互作用を考慮した磁化応答モデル構築することは学術的に意義深い。さらに生細胞環境での計測により、生体環境での粒子の形態変化を考慮した、がん診断治療への最適な粒子設計指針を得ることは社会的意義が大きい。