【作者】 李洋； 王也夫； 孙聆东； 严纯华；

【Author】 Yang Li;Ye-Fu Wang;Ling-Dong Sun;Chun-Hua Yan;State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University;

【机构】 稀土材料化学与应用国家重点实验室,北京大学化学与分子工程学院；

【摘要】 <正>稀土上转换发光材料由于具有激发光组织穿透深度大、自发荧光背景小、光稳定性与化学稳定性高等优点,在生物成像领域受到广泛关注,但是其上转换发光量子产率低,发射光组织内散射强度大也成为其在活体成像应用时的弊端。而稀土下迁移近红外发光过程,有效克服了上转换材料的以上缺点,为稀土发光材料在生物成像领域提出新的思路。我们合成了NaGdF4:Nd,Yb纳米颗粒,激发Nd3+时观察到高效率的Nd3+→Yb3+能量传递和Yb3+在980 nm的近红外发光。进一步构筑了NaGdF4:Nd,Yb@NaGdF4核-壳结构,其在有机相中量子产率达29%,水相更多还原

【Abstract】 Rare earth(RE) upconversion nanoparticles(UCNPs) have been widely used in bio-imaging for the high penetration depth of excitation light, low autofluorescence, good photo- and chemical stability. However, its low quantum yield(QY) and high scattering of in vivo tissue limit the further bio-imaging application. However, RE down-shifting nanoparticles with NIR emissions, markedly overcome these shortages. Efficient Nd3+→Yb3+ ET was observed in NaGdF4:Nd,Yb NPs, where Yb3+ emits at 980 nm when Nd3+ is excited. After coating with undoped shells, the QY of NaGdF4:Nd,Yb@NaGdF4 NPs reached 29%(in organic phase) and 24%(in water phase), respectively. In vivo experiments carried out with the NIR-emitting NPs showed successful imaging of multiple targets in nude mice. Two-step ligand exchange method successfully achieved surface modification of NPs with polyethylenimine(PEI), polyacrylene(PAA) and folic acid, for studying the size and surface-modification group effects on in vivo imaging.更多还原