title: Functionalized europium nanorods for in vitro imaging.
abstract: Emissive europium hydroxide nanorods (ENR) (20 nm x 500 nm) functionalized by a surface coating of chromophore-containing organically modified silicate (ORMOSIL) layer, have been synthesized and characterized by high-resolution transmission electron microscopy (TEM). Low-temperature photophysical characterization of the functionalized nanorods (FENR) demonstrated a strong red 5D0 luminescence both in solid and in suspended solutions. Potentials of this nanorod material for live cell imaging have also been explored. Both the bare and functionalized nanorods are able to enter living human cells with no discernible cytotoxicity. Chromophore-to-Eu3+ energy-transfer in the functionalized nanorods enables staining of the cytoplasm of living human cells. This is confirmed by costaining with fluorescent dextran. The red chromophore-sensitized luminescence from the internalized nanorods in live human lung carcinoma cells (A549) can be observed by confocal microscopy 2 h after loading and reaches maximal emission after 24 h.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
authors.forename: Ka-Leung
authors.initials: KL
authors.lastname: Wong
authors.forename: Ga-Lai
authors.initials: GL
authors.lastname: Law
authors.forename: Margaret B
authors.initials: MB
authors.lastname: Murphy
authors.forename: Peter A
authors.initials: PA
authors.lastname: Tanner
authors.forename: Wing-Tak
authors.initials: WT
authors.lastname: Wong
authors.forename: Paul Kwan-Sing
authors.initials: PK
authors.lastname: Lam
authors.forename: Michael Hon-Wah
authors.initials: MH
authors.lastname: Lam
mesh_terms: D001565:Benzoates / Q000737:chemistry; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002863:Chromogenic Compounds / Q000737:chemistry; D005063:Europium / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D006878:Hydroxides / Q000737:chemistry*; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D043942:Nanotubes / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry; D013194:Staining and Labeling; D013499:Surface Properties
chemical_list: D001565:Benzoates; D002863:Chromogenic Compounds; D005456:Fluorescent Dyes; D006878:Hydroxides; D012833:Siloxanes; C510784:ormosil; D005063:Europium; C017618:3-phenoxybenzoic acid