葡聚糖修饰Fe3O4磁性纳米粒子的同步辐射光电子能谱研究

Synchrotron radiation photoelectron spectroscopy study of dextran-coated Fe_3O_4 magnetic nanoparticles

在纳米Fe3O4表面修饰葡聚糖可在粒子表面建立空间位阻稳定层,不仅提高了纳米粒子在水中的分散稳定性,还增强了纳米粒子的生物相容性。本文在柠檬酸钠介质中合成了葡聚糖修饰的Fe3O4纳米粒子,采用同步辐射X射线光电子能谱(XPS)对未经修饰和葡聚糖修饰后的Fe3O4纳米粒子表面的化学组分、表面原子的化学结构、化学键合情况进行了定性和定量分析,并给出葡聚糖修饰Fe3O4纳米粒子的反应机理。结果表明,反应体系中的柠檬酸钠首先在Fe-O-C键包覆到Fe3O4纳米粒子表面,然后葡聚糖分子与纳米粒子外的COO-以氢键结合并同时发生葡聚糖大分子缠绕包裹连接到纳米粒子表面,这大大增强了反应体系的分散稳定性和葡聚糖修饰氧化铁纳米粒子的亲水性。

Dextran-coated Fe3O4 nanoparticles were prepared by untrasonification of Fe304 nanoparticles with dextran at 85℃ in sodium citrate medium. The surface chemical component, structure and bond of uncoated and dextran-coated nanoparticles were measured by synchrotraon radiation XPS （X-ray photoelectron spectroscopy）. Qualitative and quantitative analysis of C1s and O1s of Fe3O4 and dextran-Fe3O4 showed that the Fe3O4 nanoparticles were successively coated by sodium citrate via Fe-O-C bond, and dextrans, which can be linked with their carboxylate moiety via hydrogen bond. Sodium citrate could enhance the disperse stability of reaction system and hydrophilicity of dextran-Fe3O4.