Synthèse de Nouveaux Fluorophores Activables, Solubles dans l’eau avec des émissions ciblées pour du FRET et de l’Imagerie Microscopique – FluoMag

In this project, a library of novel classes of multichromophoric systems derived from the use of water soluble borodipyrromethene dyes (Bodipys') as the fluorophore will be designed and synthesized. New methodologies and synthetic protocols will be establish to prepare families of dyes some of which carrying multiple functions. The project will address the problems of water solubility, chemical and photochemical stability and high Stokes' shifts (>10,000 cm-1). Various highly fluorescent dyes ('>50%) absorbing and emitting light over a large spectral window (500 to 850 nm) will be designed. The water solubilisation is insured by using zwitterionic fragments, sulfonated polypeptides, polyphosphonated linear or dentritic residues. A second generation of pro-fluorescent dyes possessing all previous attributes but with chemical modules which inhibit the FRET or fluorescence (eg nitro groups) by electron transfer will as be prepared. Enzyme activation (eg caspase) or one or two photon irradiation will restore the fluorescence. The enzymatic and decaging processes will be followed in cuvettes or ultimately in living cells on the all ready existing imaging platforms in Rouen and Strasbourg. By decreasing the energetics of the electron accepting fragment (nitro derivative) likely the Bodipy will serve as an antennae and decaged the substrate by irradiation. The cell internalization will be favoured by substitution of BF2 by B-ethynyl fragments bearing polyethylene glycol chains. Furthermore, more rigid fluorophores by grafting thiophene fragments and by ring fusion will be developed using novel and integrated technologies based on scadium and tin chemistry. Likewise the solubility problems will be addressed using polyaminosulfonated solubilization head groups. Finally, multi-FRET systems will be designed and prepared with preorganized functional platforms likely having a C3 symmetry in which the FRET will be directional and controlled by the presence of specific cations or protons. This will open the possibility to perform in the future multiplexing analysis devices. By virtue of the superiorities of the relatively high stability imported by the chemistry at the boron, and colour-tuning capability spanned over the entire visible spectrum, the present project aims to explore new concepts. This tout en un concept would aid the future design and development of FRET applications by providing a catalogue of new dyes. The proposal integrates in a unique manner, complementary expertises (chemical synthesis, spectroscopy, biological labelling, enzymz activation, decaging processes and cell imaging). This guarantees that each of the fundamental steps of the project will be performed at the highest possible level. The result should be new insight into the rational design of new dyes with hitherto unimaginable properties and applications for energy transduction. Although this project is aimed at fundamental research, we foresee numerous important opto-electronic applications and new technological breakthrough. Central to the success of this project is the exceptional amount of complementary expertise provide by both partners and their scientific environment.