Dresden 2011 – scientific programme

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ISS: Intersectional Sessions

ISS 7: Transport and Spectroscopy in Molecular Nanostructures II (CPP, MO, related to SYMN)

ISS 7.9: Talk

Thursday, March 17, 2011, 12:30–12:45, TOE 317

Single molecule diffusion in columnar functionalized mesoporous rods — •Florian Feil, Valentina Cauda, Jens Michaelis, Thomas Bein, and Christoph Bräuchle — Physikalische Chemie, LMU München, Germany

Mesoporous silica materials are ideally suited as host-guest systems in nanoscience with applications ranging from molecular sieves, catalysts, nanosensors to drug delivery systems. For all these applications a thorough understanding of the interactions between the mesoporous host system and the guest molecules is vital. Here, we investigated fluorescent dyes as guest molecules acting as molecular probes that were loaded into the channels of mesoporous filaments. The dye AS-TDI was used as a tool to explore the nanoporous channel structure. By sputtering the sample with a very thin layer of gold, which quenches all molecules on the surface, we could show that the molecules were diffusing inside the structure along the columnar channels. Additionally, we could measure the orientation of the TDI molecules, as the channels have such a small diameter that the molecules are not able to rotate freely but have to align parallel to the channels. In a further approach we also succeeded in loading fluorescently labelled DNA into such a mesoporous host system. As mentioned above, we ensured by gold-sputtering that the DNA resides inside the channels and not on the surface of the filaments. Finally, it could be shown by using FRET measurements that the DNA is still intact inside the mesopores. Moreover, we were able to observe DNA diffusion inside the filament channels.