title: Multifunctional rare-earth self-assembled nanosystem for tri-modal upconversion luminescence /fluorescence /positron emission tomography imaging.
abstract: Rare-earth upconversion nanoparticles (UCNP) which can absorb low-energy photons and emit high energy photons have attracted great interest not only because of their unique application in upconversion luminescence imaging, but also because they can be used as ideal building blocks for multimodal bioimaging probes. Improving the water-solubility of UCNP and functionalizing them are as yet unresolved problems. In this present study, a general strategy was developed to achieve these two aims by converting hydrophobic upconversion nanoparticles into hydrophilic ones. This was based on the self-assembly between oleic acid, which is a capping ligand, as the guest molecule, and alpha-cyclodextrin, as the host molecule, no matter what the particle size was (10-400 nm) or what synthesis method (thermal decomposition, hydrothermal, solvothermal) was used. The synthesized hydrophilic nanoparticles can further load hydrophobic molecule, e.g. Os(II) complex. The process of self-assembly and loading was confirmed by transmission electron microscopy, X-ray powder diffraction, (1)H-nuclear magnetic resonance, Fourier transform-infrared and thermogravimetric analysis, upconversion luminescence and fluorescence spectra. Further bioapplication has also been investigated, including cell-labeling, in vivo lymphatic imaging, upconversion luminescence and positron emission tomography imaging of whole-body Kunming mice. The results indicate that this method is a potential candidate for the preparation of hydrophilic UCNP as a multimodal nanoprobe.
authors.affiliation: Department of Chemistry & Advanced Materials Laboratory, Fudan University, 200433, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Yun
authors.initials: Y
authors.lastname: Sun
authors.forename: Guoying
authors.initials: G
authors.lastname: Chen
authors.forename: Tianshe
authors.initials: T
authors.lastname: Yang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.forename: Xianzhong
authors.initials: X
authors.lastname: Zhang
authors.forename: Fuyou
authors.initials: F
authors.lastname: Li
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival; D004396:Coloring Agents / Q000737:chemistry; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008163:Luminescent Measurements / Q000379:methods*; D008208:Lymphatic System / Q000473:pathology; D008674:Metals, Rare Earth / Q000737:chemistry*; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D019301:Oleic Acid / Q000737:chemistry; D049268:Positron-Emission Tomography / Q000379:methods*; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D014018:Tissue Distribution; D051598:Whole Body Imaging; D047391:alpha-Cyclodextrins / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D008674:Metals, Rare Earth; D047391:alpha-Cyclodextrins; D019301:Oleic Acid; C032613:alpha-cyclodextrin