Lv Ruichan, Gai Shili, Dai Yunlu, He Fei, Niu Na, Yang Piaoping
Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University , Harbin 150001, People's Republic of China.
Inorg Chem. 2014 Jan 21;53(2):998-1008. doi: 10.1021/ic402468k. Epub 2013 Dec 23.
Uniform LaF3 and LaCO3F hollow microspheres were successfully synthesized through a surfactant-free route by employing La(OH)CO3 colloidal microspheres as a sacrificial template and NaBF4 as the fluorine source. The synthetic process consists of two steps: the preparation of a La(OH)CO3 precursor via a facile urea-based precipitation and the following formation of lanthanide fluoride hollow microspheres under aqueous conditions at low temperature (50 °C) and short reaction time (3 h), without using any surfactant and catalyst. The formation of hollow spheres with controlled size can be assigned to the Kirkendall effect. It is found that the phase and structure of the products can be simply tuned by changing the pH values of the solution. Time-dependent experiments were employed to study the possible formation process. N2 adsorption/desorption results indicate the mesoporous nature of LaF3 hollow spheres. Yb(3+)/Er(3+) (Ho(3+)) and Yb(3+)/Tm(3+)-doped LaF3 hollow spheres exhibit characteristic up-conversion (UC) emissions of Er(3+) (Ho(3+)) and Tm(3+) under 980 nm laser-diode excitation, and Ce(3+)/Tb(3+)-doped LaF3 and LaCO3F emit bright yellow-green and near-white light under UV irradiation, respectively. In particular, LaF3:Yb/Er and LaCO3F:Ce/Tb hollow microspheres exhibit obvious sustained and pH-dependent doxorubicin release properties. The luminescent properties of the carriers allow them to be tracked or monitored during the release or therapy process, suggesting their high potential in the biomedical field.
通过以碱式碳酸镧胶体微球为牺牲模板、硼氢化钠为氟源，采用无表面活性剂的方法成功合成了均匀的氟化镧和氟碳酸镧空心微球。合成过程包括两个步骤：通过简便的尿素沉淀法制备碱式碳酸镧前驱体，以及随后在低温（50℃）和短反应时间（3小时）的水相条件下，不使用任何表面活性剂和催化剂形成镧系氟化物空心微球。具有可控尺寸的空心球的形成可归因于柯肯达尔效应。发现通过改变溶液的pH值可以简单地调节产物的相和结构。采用时间相关实验来研究可能的形成过程。氮气吸附/脱附结果表明氟化镧空心球具有介孔性质。在980nm激光二极管激发下，掺杂Yb(3+)/Er(3+)（Ho(3+)）和Yb(3+)/Tm(3+)的氟化镧空心球表现出Er(3+)（Ho(3+)）和Tm(3+)的特征上转换（UC）发射，而掺杂Ce(3+)/Tb(3+)的氟化镧和氟碳酸镧在紫外光照射下分别发出亮黄绿色和近白色光。特别地，氟化镧:Yb/Er和氟碳酸镧:Ce/Tb空心微球表现出明显的持续且依赖pH的阿霉素释放特性。载体的发光性质使其在释放或治疗过程中能够被追踪或监测，表明它们在生物医学领域具有很高的潜力。
