核壳结构Ag@BaGdF5:Yb3+,Ho3+多功能纳米复合材料的制备及其性能

采用简单的液相法制备了核壳结构的Ag@BaGdF_5∶Yb~(3+),Ho~(3+)纳米复合材料。XRD测试表明复合材料中含有立方相的Ag和立方相的BaGdF_5。电镜照片表明复合粒子为球形,包覆后颗粒变大,包覆层BaGdF_5∶Yb~(3+),Ho~(3+)的厚度约为14 nm。荧光光谱测试表明复合材料具有良好的上转换发光性能,以绿光发射最强,同时样品具有良好的顺磁性和光热转换性能。MTT测试表明复合材料具有良好的生物相容性,将其同HeLa细胞共同培养后用980 nm激光照射,具有明亮的绿色上转换荧光成像。将不同浓度的纳米复合材料和商用计算机断层扫描(CT)成像造影剂碘比醇进行比较,纳米复合材料具有更高的CT成像性能。在NIR照射下,纳米复合材料生成的热足以有效杀死HeLa细胞。

Synthesis and Properties of Core-Shell Structure Ag@BaGdF5: Yb3+, Ho3+ Multifunctional Nanocomposites

Core-shell structure multifunctional Ag@BaGdF₅:Yb³⁺, Ho³⁺ nanocomposites were prepared by a simple wet method. XRD patterns showed that the nanocomposites consisted of cubic phase Ag and BaGdF₅. Electron microscope images indicated that the nanocomposites were spherical shape with the thickness of~14 nm (BaGdF₅:Yb³⁺, Ho³⁺ as shell) and a diameter of 77 nm (Ag nanoparticles as core). The nanocomposites had good upconversion emission with the strongest green emission centered at about 540 nm from the photoluminescence spectra, which is helpful to apply in intracellular imaging to diagnose lesion. Furthermore, the samples possessed better paramagnetism and photothermal conversion properties. MTT measurement demonstrates that the nanocomposites have better biocompatibility. When incubated with HeLa cells, the nanocomposites had bright green upconversion imaging under 980 nm irradiation. Compared with commercial computed tomography (CT) imaging contrast agent iobitridol, the Ag@BaGdF₅:Yb³⁺, Ho³⁺ nanocomposites had higher CT imaging properties. The heat converted from the nanocomposites could kill HeLa cells.