title: Two-photon excited fluorescence of silica nanoparticles loaded with a fluorene-based monomer and its cross-conjugated polymer: their application to cell imaging.
abstract: In this work the two-photon activity of nanoparticles obtained from a fluorene monomer (M1) and its cross-conjugated polymer (P1) is reported. Aqueous suspensions of M1 and P1 nanoparticles prepared through the reprecipitation method exhibited maximum two-photon absorption (TPA) cross-sections of 84 and 9860 GM (1 GM = 10(-50) cm(4) s) at 740 nm, respectively, and a fluorescence quantum yield of ~1. Such a two-photon activity was practically equal with respect to that for molecular solutions of M1 and P1. These materials were then successfully encapsulated into silica nanoparticles to provide bio-compatibly. A lung cancer cell line (A549) and a human cervical cancer cell line (HeLa cells) were incubated with our fluorescent silica nanoparticles to carry out two-photon imaging. By means of these studies we demonstrate that optimized nonlinear optical polymers loaded in silica nanoparticles can be used as efficient probes with low cytotoxicity and good photostability for two-photon fluorescence microscopy. To the best of our knowledge, studies concerning polymer-doped silica nanoparticles exhibiting large two-photon activity have not been reported in the literature.
authors.affiliation: Centro de Investigaciones en Óptica A.C., A.P. 1-948, 37000 León, Gto., Mexico.
authors.forename: Laura
authors.initials: L
authors.lastname: Aparicio-Ixta
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ramos-Ortiz
authors.forename: Juan L
authors.initials: JL
authors.lastname: Pichardo-Molina
authors.forename: José Luis
authors.initials: JL
authors.lastname: Maldonado
authors.forename: Mario
authors.initials: M
authors.lastname: Rodríguez
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Tellez-Lopez
authors.forename: Daniel
authors.initials: D
authors.lastname: Martinez-Fong
authors.forename: Mikhail G
authors.initials: MG
authors.lastname: Zolotukhin
authors.forename: Serguei
authors.initials: S
authors.lastname: Fomine
authors.forename: Marco A
authors.initials: MA
authors.lastname: Meneses-Nava
authors.forename: Oracio
authors.initials: O
authors.lastname: Barbosa-García
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005449:Fluorenes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D017785:Photons; D011108:Polymers / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D005449:Fluorenes; D011108:Polymers; C041509:fluorene; D012822:Silicon Dioxide