This work reports the fabrication of magnetite (Fe₃O₄) nanoparticles (NPs) coated with various biocompatible surfactants such as glutamic acid (GA), citric acid (CA), polyethylene glycol (PEG), polyvinylpyrrolidine (PVP), ethylene diamine (EDA) and cetyl-trimethyl ammonium bromide (CTAB) via co-precipitation method and their comparative inductive heating ability for hyperthermia (HT) applications. X-ray and electron diffraction analyses validated the formation of well crystallined inverse spinel structured Fe₃O₄ NPs (crystallite size of ~ 8–10 nm). Magnetic studies confirmed the superparamagnetic (SPM) behaviour for all the NPs with substantial magnetisation (63–68 emu/g) and enhanced magnetic susceptibility is attributed to the greater number of occupations of Fe²⁺ ions in the lattice as revealed by X-ray photoelectron spectroscopy (XPS). Moreover, distinctive heating response (specific absorption rate, SAR from 130 to 44 W/g) of NPs with similar size and magnetisation is observed. The present study was successful in establishing a direct correlation between relaxation time (~ 9.42–15.92 ns) and heating efficiency of each surface functionalised NPs. Moreover, heat dissipated in different surface grafted NPs is found to be dependent on magnetic susceptibility, magnetic anisotropy and magnetic relaxation time. These results open very promising avenues to design surface functionalised magnetite NPs for effective HT applications.

这项工作报告了磁铁矿 (Fe ₃ O ₄ ) 纳米粒子 (NPs)的制备，该纳米粒子涂有各种生物相容性表面活性剂，如谷氨酸 (GA)、柠檬酸 (CA)、聚乙二醇 (PEG)、聚乙烯吡咯烷 (PVP)、乙二胺 ( EDA) 和十六烷基三甲基溴化铵 (CTAB) 通过共沉淀法及其在热疗 (HT) 应用中的比较感应加热能力。X 射线和电子衍射分析验证了结晶良好的反尖晶石结构 Fe ₃ O _{4 的形成}NP（微晶尺寸约为 8–10 nm）。磁性研究证实了所有具有显着磁化强度 (63–68 emu/g) 的 NPs 的超顺磁性 (SPM) 行为，增强的磁化率归因于更多的 Fe ²⁺占据X 射线光电子能谱 (XPS) 显示晶格中的离子。此外，观察到具有相似尺寸和磁化强度的纳米颗粒的独特加热响应（比吸收率，SAR 从 130 到 44 W/g）。本研究成功地建立了弛豫时间（~ 9.42-15.92 ns）与每个表面功能化纳米颗粒的加热效率之间的直接相关性。此外，发现不同表面接枝纳米颗粒的散热取决于磁化率、磁各向异性和磁弛豫时间。这些结果为设计用于有效 HT 应用的表面功能化磁铁矿 NP 开辟了非常有前途的途径。