Magnetic Anisotropy Dominates over Physical and Magnetic Structure in Performance of Magnetic Nanoflowers

被引：2

作者：

Borchers, Julie ^{[1
]}

Krycka, Kathryn ^{[1
]}

Bosch-Santos, Brianna ^{[2
]}

Correa, Eduardo de Lima ^{[2
,3
]}

Sharma, Anirudh ^{[4
]}

Carlton, Hayden ^{[4
]}

Dang, Yanliu ^{[2
]}

Donahue, Michael ^{[5
]}

Gruettner, Cordula ^{[6
]}

Ivkov, Robert ^{[4
,7
,8
,9
]}

Dennis, Cindi L. ^{[2
]}

机构：

[1] Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA

[2] Natl Inst Stand & Technol, Mat Measurement Lab, Gaithersburg, MD 20899 USA

[3] Theiss Res, La Jolla, CA 92037 USA

[4] Johns Hopkins Univ, Sch Med, Dept Radiat Oncol & Mol Radiat Sci, Baltimore, MD 21231 USA

[5] Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA

[6] Micromod Partikeltechnol GmbH, D-18119 Rostock, Germany

[7] Johns Hopkins Univ, Sch Med, Sydney Kimmel Comprehens Canc Ctr, Dept Oncol, Baltimore, MD 21231 USA

[8] Johns Hopkins Univ, Whiting Sch Engn, Dept Mech Engn, Baltimore, MD 21218 USA

[9] Johns Hopkins Univ, Whiting Sch Engn, Dept Mat Sci & Engn, Baltimore, MD 21218 USA

来源：

SMALL STRUCTURES | 2025年 / 6卷 / 02期

基金：

美国国家科学基金会; 美国国家卫生研究院;

关键词：

magnetic anisotropy; magnetic nanoparticles; nanoflowers; small angle neutron scattering; IRON-OXIDE NANOPARTICLES; CONTRAST AGENTS; HYPERTHERMIA; POLARIZATION; EFFICIENCY; FORMULATION; RADIATION; THERAPY; TUMORS; MODEL;

D O I：

10.1002/sstr.202400410

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Magnetic nanoparticles are indispensable in many biomedical applications, but it remains unclear how the composition and structure will influence the application specific performance. We consider two compositions, ferrite and cobalt ferrite, synthesized under conditions that create aggregated multi-core nanoparticles, called nanoflowers. Each nanoflower has an ionic surfactant or dextran to provide colloid stability in water. The composition, but not the coating, greatly impacts the heating output and the magnetic particle imaging tracer quality (with cobalt ferrite significantly reduced compared to ferrite). The cobalt ferrite nanoflowers have a core/shell structure with a reduced magnetization, which limits the effective magnetic anisotropy of the individual cobalt ferrite nanoflowers as well as the magnetic interactions among the nanoflowers. Both limitations significantly reduce the overall increase in the magnetic anisotropy with increasing magnetic field and consequently the nanoflowers' efficacy for heating and imaging. Despite this, the formation of denser-packed clusters and chains with external magnetic field in the ionic surfactant-cobalt ferrite nanoflowers overcomes some of the shell's detrimental effects, resulting in better heating and imaging properties compared to the dextran-cobalt ferrite. In short, the magnetic anisotropy dominates over physical and magnetic structure in the performance of the studied nanoflowers for heating and imaging applications. Idealized schematics showing example magnetic nanoflower colloidal structures, consistent with the small angle neutron scattering data. The chains increase the overall magnetic anisotropy which controls the MNFs' effectiveness for magnetic particle imaging and magnetic nanofluid hyperthermia. This anisotropy increase can overcome other detrimental effects like shell formation, but, if the increase is too large, may become detrimental.image (c) 2024 WILEY-VCH GmbH

引用

页数：23