title: A self-assembled nanohybrid composed of fluorophore-phenylamine nanorods and Ag nanocrystals: energy transfer, wavelength shift of fluorescence and TPEF applications for live-cell imaging.
abstract: A fluorophore-phenylamine derivative (L) has been coupled with silver nanocrystals (NCs) to construct an L-Ag nanohybrid. Owing to synergic effects of the L and Ag components, the exciton-plasmon interactions between L and Ag increase the strength of the donor-acceptor interaction within the nanohybrid, a fact that results in an energy-transfer process and further brings about a dramatic redshift of single-photon absorption and fluorescence, and a decreased fluorescence FL lifetime. The coupling effect also leads to enhancement of a series of nonlinear optical properties, including two-photon-excited fluorescence (TPEF), two-photon-absorption (TPA) cross section (δ), two-photon-absorption coefficient (β), nonlinear refractive index (γ), and third order nonlinear optical susceptibility (χ((3))). The enhanced two-photon fluorescence of the nanohybrid is proven to be potentially useful for two-photon microscopy of live cells, such as HepG2. Moreover, cytotoxicity tests show that the low-micromolar concentrations of the nanohybrid do not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies.
authors.affiliation: Department of Chemistry, Key Laboratory of Inorganic Materials Chemistry of Anhui Province, Anhui University, 111 Jiu-Long Road, Hefei, 230039 (P.R. China), Fax: (+86) 551-63861279.
authors.forename: Lin
authors.initials: L
authors.lastname: Kong
authors.forename: Jia-xiang
authors.initials: JX
authors.lastname: Yang
authors.forename: Sheng-li
authors.initials: SL
authors.lastname: Li
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.forename: Zhao-ming
authors.initials: ZM
authors.lastname: Xue
authors.forename: Hong-ping
authors.initials: HP
authors.lastname: Zhou
authors.forename: Jie-ying
authors.initials: JY
authors.lastname: Wu
authors.forename: Bao-kang
authors.initials: BK
authors.lastname: Jin
authors.forename: Yu-peng
authors.initials: YP
authors.lastname: Tian
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D002470:Cell Survival; D004735:Energy Transfer; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D061848:Optical Imaging; D012834:Silver / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D005456:Fluorescent Dyes; D012834:Silver
keywords: TPEF cell imaging; dye-metal nanohybrid; energy transfer; exciton-plasmon interaction; nonlinear optics