Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
AKB: Biologische Physik
AKB 40: Poster Session II
AKB 40.45: Poster
Mittwoch, 29. März 2006, 16:30–19:30, P3
Investigation of ion channel function with a high frequency approach — •Michael Olapinski1, Andrea Brüggemann2, Michael George2, Niels Fertig2, Stephan Manus1, and Friedrich C. Simmel1 — 1Department für Physik, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany — 2Nanion Technologies GmbH, Pettenkoferstr. 12, 80336 München, Germany
Due to the limited bandwidth of the measurement setup, classical patch-clamp techniques cannot be used to study fast dynamical processes within ion channel proteins which may influence ionic transport. To overcome this limitation, chip-based methods are explored to study ion channel dynamics with the help of high-frequency (HF) techniques.
We present an approach, where a patch-clamp on-a-chip system is combined with an open-end coaxial probe that is positioned in close proximity to the cells under investigation. Ionic currents through the cell membrane are measured in whole-cell configuration while HF fields are applied at frequencies from MHz to 40 GHz. The ionic currents measured with rat basophil leukaemia (RBL) cells containing a potassium channel are sensitive to the applied HF field in specific frequency ranges and depend on the presence of potassium ions and the applied membrane potential. However, local heating of the buffer can be shown to play an important role in this case. Using a lock-in technique with a modulated HF excitation, it becomes possible to differentiate between thermal effects caused by the HF irradiation and intrinsic effects in which the field couples to membrane polarization and ion channel dynamics.