Regensburg 2004 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.74: Poster

Freitag, 12. März 2004, 10:30–13:00, B

Capacitive Opening of Ion Channels in Cell Membranes on Silicon Chips — •Maximilian H. Ulbrich und Peter Fromherz — Max Planck Institute for Biochemistry, Dept. Membrane and Neurophysics, Am Klopferspitz 18 a, 82152 Martinsried

In order to understand and optimize capacitive excitation of neurons from silicon microstructures, it is necessary to study the response of defined voltage-gated ion channels to voltage transients applied to a chip. /par HEK 293 cells were stably transfected with Kv1.3 potassium channels. The cells were cultured on silicon chips insulated with a thin dielectric and coated with fibronectin. Voltage transients were applied to the chip. They were chosen such that capacitive coupling gave rise to a stationary voltage in the narrow extracellular space between chip and cell. The resulting changes of potassium current through the attached membrane were recorded at constant intracellular voltage using whole-cell patch clamp. /par We succeeded in capacitive gating of Kv1.3 channels through negative extracellular voltages elicited from silicon. Extracellular voltage-clamp with sufficient amplitude and sufficient duration required, however, an enhanced time constant of high pass coupling that was achieved with a high-k dielectric on silicon and a high resistance of the electrolyte.