Near-IR Two Photon Microscopy Imaging of Silica Nanoparticles Functionalized with Isolated Sensitized Yb(III) Centers
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- 作者：Giuseppe Lapadula ; Adrien Bourdolle ; Florian Allouche ; Matthew P. Conley ; Iker del Rosal ; Laurent Maron ; Wayne W. Lukens ; Yannick Guyot ; Chantal Andraud ; Sophie Brasselet ; Christophe Copéret ; Olivier Maury ; Richard A. Andersen
- 刊名：Chemistry of Materials
- 出版年：2014
- 出版时间：January 28, 2014
- 年：2014
- 卷：26
- 期：2
- 页码：1062-1073
- 全文大小：538K
- ISSN：1520-5002
文摘
Bright nano-objects emitting in the near-infrared with a maximal cross section of 41.4 脳 103 GM (Goppert Mayer) were prepared by implanting ca. 180 4,4鈥?diethylaminostyryl-2,2鈥?bipyridine (DEAS) Yb(III) complexes on the surface of 12-nm silica nanoparticles. The surface complexes ([DEAS路Ln@SiO2], Ln = Y, Yb) were characterized using IR, solid-state NMR, UV-vis, and EXAFS spectroscopies in combination with the preparation and characterization of similar molecular analogues by analytical techniques (IR, solution NMR, UV鈥搗is, X-ray crystallography) as well as DFT calculations. Starting from the partial dehydroxylation of the silica at 700 掳C under a high vacuum having 0.8 OH路nm鈥?, the grafting of Ln(N(SiMe3)2)3 generates 鈮iO鈥揕n(N(SiMe3)2)2, which upon thermal step and coordination of the DEAS chromophore yields (鈮iO)3Ln(DEAS). Surface and molecular analogues display similar properties, in terms of DEAS binding constants absorption maxima and luminescence properties (intense emission band assigned to a ligand centered CT fluorescence and lifetime) in the solid state, consistent with the molecular nature of the surface species. The densely functionalized nanoparticles can be dispersed via ultrasonication in small 15鈥?0 nm aggregates (one to six elementary particles) that were detected using two-photon microscopy imaging at 720 nm excitation, making them promising nano-objects for bioimaging.