Dresden 2009 – scientific programme
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BP: Fachverband Biologische Physik
BP 12: Single Molecules
BP 12.4: Talk
Wednesday, March 25, 2009, 10:45–11:00, HÜL 186
Reversible Affinity Switching of a Single Supramolecular Receptor Molecule — •Volker Walhorn1, Christian Schäfer2, Tobias Schröder3, Jochen Mattay3, and Dario Anselmetti1 — 1Experimental Biophysics and Applied Nanosciences, Bielefeld University — 2Organic Nanosciences University of Bordeaux 1 — 3Organic Chemisty Bielefeld University
Photoactivation of single molecules is a common concept in nature. In order to investigate such mechanisms we synthesized a bistable supramolecular complex consisting of a Resorc[4]arene receptor cavity modified with two anthracene moieties. These can be switched between two isoforms either by UV-light or heat [1]. Using atomic force microscope based single molecule force spectroscopy (AFM-SMFS) we investigated the conformation dependent receptor affinity to different ammonium derivates. Our results show that this system can be reversely and repeatedly switched between two different isomeric conformations accompanied by a drastic change of affinity to ammonium ligands. For the "open" high affinity state we could also demonstrate the specificity by competition experiments and estimate associated binding properties like reaction lengths (xβ) and thermal off-rate constants (koff). Robust bistable molecular systems are potential candidates for novel concepts in bio-medical, analytics, directed molecular assembly or controlled drug delivery.
[1] C. Schäfer et. al. J. Am. Chem. Soc. 2007, 129, 1488-1489