High resolution structure characterisation and stabilisation of supramolecular architectures using novel perfluoralkyl functionalised dendron-amphiphiles with dye spacers as optical probes

• Applicants: Privatdozent Dr. Christoph Böttcher; Professor Dr. Rainer Haag
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317551446

Supramolecular assemblies can be characterised in their quasi native state on the nano scale using cryogenic transmission electron microscopy (cryo-TEM), but an exact determination of the molecular organisation is achieved in only rare cases. If utilising particular cyanine dyes as an integrated component of an amphiphilic self-assembling systems, their optical properties, which alter in a specific way upon aggregation (e.g. by the formation of H- and J-aggregates), can, however, be used for a complementary determination of the molecular arrangement within the nanoscopic framework. Consequently, crucial parameters for an understanding of the self-organisation process on the molecular level are available.On the basis of these findings, we propose a new type of amphiphilic molecules in order to (a) characterise their self-assembled architectures, (b) produce photostable supramolecular aggregates, and (c) establish diagnostic transporters which are capable of self-signalling the release of their payloads. Our approach combines the particular properties of dendritic polyglycerol head groups of differing generations (G1-G3) and the optical properties of cyanine dye probes. In addition, alkyl chains as well as fluorinated alkyl chains will be introduced and their structure forming properties be characterised by spectroscopy and direct imaging techniques, in particular Cryo-TEM or Cryo-Electron Tomography. The combined efficacy of the hydrophobic effect, directional properties of dendritic head groups, the aggregation tendency of dye systems, as well as compartimentalisation effect (microphase separation) of fluorinated chains aims at the creation of particularly stable and structurally defined ultrastructures, which are applicable as specialised transporters due to their enhanced photostability and optical properties.

• DFG Programme: Research Grants