Dresden 2009 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 12: Single Molecules

BP 12.4: Vortrag

Mittwoch, 25. März 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 (x_β) and thermal off-rate constants (k_off). 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