Functionalized OSK rods for optical sensing

• Applicants: Professor Dr. Michael U. Kumke; Professor Dr. Pablo Wessig
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 255921230

In the interdisciplinary research project Funktionalisierte OSK-Stäbe für optische Sensorik (functionalized OSK rods for optical sensing) the synthesis and detailed physico-chemical characterization of a new class of molecular rods labeled with new fluorescent dyes is envisaged. The dye-labeled oligospiroketal (OSK) rods will be evaluated for distance-, environment- and force-sensitive measurements. Novel structural motives with respect to fluorophore, linker, and spacer will be investigated. Based on the OSK rods the molecular dimensions of the spacer and the possibilities of intramolecular interactions will be distinctly reduced yielding an improved tool box of fluorescence probes for life science studies (e.g., investigation of membrane processes), in which DBD dyes will be used as fluorophores. Rigid OSK rods labeled with one or two fluorophores as well as OSK rods with a flexible unit will be investigated. In addition to the environmental sensitivity of the DBD dyes (with can be adjusted) also the concept of distance dependent sensing based on Förster resonance energy transfer (FRET) is pursuit. Because of the outstanding control of the rod properties including the relative orientation (flexibility of linker) of donor and acceptor dye, fundament aspects of FRET will be tackled as well (point dipole approximation or systems with orientation factors >> 2/3). The dye-labeled OSK rods will be further into an optical method to detect molecular forces. In a combination with atomic force microscopy (AFM) the alterations in the fluorescence parameters (fluorescence quantum yield, fluorescence decay time) will be evaluated. Here, the molecular rods are immobilized on a AFM tip and/or a sample surface (e.g., Au) and the AFM is used to vary the distance the fluorophores or the fluorophore and the surface. With the dye-labeled OSK rods a novel tool box for an optical force sensing can be envisaged.

• DFG Programme: Research Grants