title: Controlled click-assembly of well-defined hetero-bifunctional cubic silsesquioxanes and their application in targeted bioimaging.
abstract: A general procedure for the assembly of hetero-bifunctional cubic silsesquioxanes with diverse functionality and a perfectly controlled distribution of functional groups on the inorganic framework has been developed. The method is based on a two-step sequence of mono- and hepta-functionalization through the ligand-accelerated copper(I)-catalyzed azide-alkyne cycloaddition of a readily available octaazido cubic silsesquioxane. The stoichiometry of the reactants and the law of binomial distribution essentially determine the selectivity of the key monofunctionalization reaction when a copper catalyst with strong donor ligands is used. The methodology has been applied to the preparation of a set of bifunctional nano-building-blocks with orthogonal reactivity for the controlled assembly of precisely defined hybrid nanomaterials and a fluorescent multivalent probe for application in targeted cell-imaging. The inorganic cage provides an improved photostability to the covalently attached dye as well as a convenient framework for the 3D multivalent display of the pendant epitopes. Thus, fluorescent bioprobes based on well-defined cubic silsesquioxanes offer interesting advantages over more conventional fully organic analogues and ill-defined hybrid nanoparticles and promise to become powerful tools for the study of cell biology and for biomedical applications.
authors.affiliation: Instituto de Química-Física Rocasolano, IQFR-CSIC, Serrano 119, 28006 Madrid, Spain.
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Pérez-Ojeda
authors.forename: Beatriz
authors.initials: B
authors.lastname: Trastoy
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Rol
authors.forename: María D
authors.initials: MD
authors.lastname: Chiara
authors.forename: Inmaculada
authors.initials: I
authors.lastname: García-Moreno
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Chiara
mesh_terms: D000480:Alkynes / Q000737:chemistry; D001386:Azides / Q000737:chemistry; D002384:Catalysis; D057930:Click Chemistry; D003300:Copper / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D018613:Microscopy, Confocal; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D001386:Azides; D005456:Fluorescent Dyes; D008024:Ligands; D017646:Organosilicon Compounds; C525616:octakis(3-(3-amino-1,2,4-triazole)propyl)octasilsesquioxane; D003300:Copper