title: Neutral push-pull chromophores for nonlinear optical imaging of cell membranes.
abstract: A new class of push-pull molecules was recently identified, based on pyridine dicarboxamide as an electron acceptor group and bearing a fluorenethynyl pi-conjugated bridge. The molecules present good second and third order nonlinear properties, with a static quadratic hyperpolarisability mubeta (at 1.907 microm) of 320 x 10(-48) esu (mubeta(0) = 249 x 10(-48) esu) and a maximum two-photon absorption cross-section of 1146 GM. Starting from this generic structure, we designed a series of eight amphiphilic nonlinear probes, varying the length of the lipophilic tail and the nature of the polar head, and tested their cell membrane affinity by nonlinear optical imaging. A good membrane affinity was observed with probes bearing short alkyl chains and carbohydrate moieties as the polar head, emphasizing the importance of the lipophilic-hydrophilic balance, as well as the role of the polar head. This original approach based on carbohydrate head groups is an important advancement in the design of membrane probes, since these highly versatile functional groups confer adequate hydrophilicity and yet conserve overall molecular neutrality.
authors.affiliation: Université de Lyon, Laboratoire de Chimie de l'ENS Lyon, UMR 5182 CNRS-ENS Lyon, 46 allée d'Italie, 69364, Lyon, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Barsu
authors.forename: Rouba
authors.initials: R
authors.lastname: Cheaib
authors.forename: Stéphane
authors.initials: S
authors.lastname: Chambert
authors.forename: Yves
authors.initials: Y
authors.lastname: Queneau
authors.forename: Olivier
authors.initials: O
authors.lastname: Maury
authors.forename: Davy
authors.initials: D
authors.lastname: Cottet
authors.forename: Hartmut
authors.initials: H
authors.lastname: Wege
authors.forename: Julien
authors.initials: J
authors.lastname: Douady
authors.forename: Yann
authors.initials: Y
authors.lastname: Bretonnière
authors.forename: Chantal
authors.initials: C
authors.lastname: Andraud
mesh_terms: D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure*; D004396:Coloring Agents / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D018613:Microscopy, Confocal / Q000379:methods*; D008958:Models, Molecular; D015394:Molecular Structure; D009457:Neuroglia / Q000166:cytology; D011725:Pyridines / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D011725:Pyridines