摘要
具有可调组分的单分散FePt金属间化合物纳米颗粒由Mg O包覆的A1-FePt(或者A1-Fe Pt-Fe_3O_4)经过热退火,再通过酸处理除去MgO制备得到.高温退火有助于FePt从无序合金转变为有序金属间化合物.在Mg O的保护下,Fe和Pt的扩散受到限制,因而晶格中的Fe、Pt原子能够重构形成FePt金属间化合物,再通过简单的酸腐蚀可得到分散的纳米颗粒.FePt金属间化合物纳米颗粒形成面心立方和面心四方结构,通过组分调节可以改变其磁性能.随着铁含量的增加,其饱和磁化强度从8 emu g^(-1)提高到52 emu g^(-1),在铁含量为44%时,矫顽力达到最大值33kOe.利用含巯基分子对纳米颗粒表面进行亲水或疏水性改性,Fe Pt金属间化合物纳米颗粒可以溶于水和烃类溶剂.亲水的L1_0-FePt金属间化合物纳米颗粒可作为磁共振成像造影剂,表现出高的横向弛豫率(328.6 mmol^(-1)L s^(-1)),这表明FePt金属间化合物纳米颗粒有望用于肿瘤诊断的分子探针.
Dispersible FePt intermetallic nanopartides （NPs） with tunable composition were synthesized by thermal annealing of MgO coated A1-FePt （or A1-FePt-Fe304） NPs followed by an acid treatment to remove MgO. High-tem- perature annealing facilitates the conversion of FePt from disordered alloy to ordered intermetaUics. Under the protec- tion of MgO, the diffusion of Fe and Pt atoms was limited, making it possible for the atom reconstruction in the lattice to give discrete FePt intermetaUic NPs after a facile acid etching process. FePt intermetallic NPs formed face-centered cubic and face-centered tetragonal structures with their magnetic properties tuned by composition. The saturation magnetiza- tion was adjusted from 8 to 52 emu g^-1 by increasing the Fe concentration, while the coercivity reached a max/mum of 33 kOe when Fe concentration was 44%. After surface mod- ifications by hydrophilic or hydrophobic molecules containing thiol groups, FePt intermetallic NPs could be dissolved into water or hydrocarbon solvents. The hydrophilic L10-FePt in- termetallic NPs were applied as contrast agents for magnetic resonance imaging, showing a high transverse relaxivity of 328.6 mmo1^-1 L s^-l, which indicated the great potential of FePt intermetallic NPs as molecular probes for cancer diagnosis.
作者
余靓
高伟良
刘飞
鞠艳敏
赵帆
杨子煜
储鑫
车声雷
侯仰龙
Jing Yu;Weiliang Gao;Fei Liu;Yanmin Ju;Fan Zhao;Ziyu Yang;Xin Chu;Shenglei Che;Yanglong Hou(College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China;Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China;Department of Materials Science and Engineering, Iowa State University of Science and Engineering, Ames 50011, USA)
基金
supported by the National Natural Science Foundation of China (51602285, 51590882, 51631001, 51672010 and 81421004)
the National Key R&D Program of China (2017YFA0206301)
the Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and technology, Chinese Academy of Sciences (NSKF201607)
