title: Functionalized two-photon absorbing diketopyrrolopyrrole-based fluorophores for living cells fluorescent microscopy.
abstract: Two-photon excited microscopy has evolved as a routine technique for long-term cellular and in vivo imaging and is now available in most optical microscopy facilities. Classical dyes and fluorescent proteins, developed for epifluorescence or confocal microscopy, are used but unfortunately present a low efficiency upon two-photon excitation inducing the need of high excitation power (over 20 mW). To reduce this excitation power, new dyes need to be developed, allowing really low two-photon excitation power in the milliwatt or sub-milliwatt range. We report here the conception, synthesis, and physicochemical and photophysical properties of new functionalized diketopyrrolopyrrole (DPP) derivatives acting as fluorescent tags for biomolecules. They present high two-photon absorption cross-sections and bright luminescence around 600 nm. These two-photon optimized fluorophores were bioconjugated to HIV-I Tat (44-61), and their cellular localization was observed by two-photon excited microscopy using sub-milliwatt laser excitation power.
authors.affiliation: Laboratoire de Biophotonique et Pharmacologie (UMR 7213), Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, CS 60024, 67401 Illkirch, France.
authors.forename: Hussein
authors.initials: H
authors.lastname: Ftouni
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bolze
authors.forename: Hugues
authors.initials: H
authors.lastname: de Rocquigny
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Nicoud
mesh_terms: D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D015696:Gene Products, tat / Q000737:chemistry; D015497:HIV-1 / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D015394:Molecular Structure; D017785:Photons; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D015696:Gene Products, tat; D011758:Pyrroles