Berlin 2005 – scientific programme
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AKB: Biologische Physik
AKB 200: Poster Session II
AKB 200.68: Poster
Tuesday, March 8, 2005, 17:00–19:00, Poster TU C
Capacitive stimulation of recombinant voltage-gated Na+ channels on a silicon chip — •Ingmar Schön and Peter Fromherz — Dept. Membrane and Neurophysics, MPI of Biochemistry, Martinsried, Germany
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.
The model system comprises HEK293 cells stably transfected with rNaV1.4 sodium channels. The cells were cultured on a silicon chip insulated with a thin layer of hafnium oxide and coated with fibronectin. Voltage transients were applied to the chip. They were chosen such that capacitive coupling gave rise to a stationary negative voltage in the narrow extracellular space between chip and cell. The resulting changes of sodium current through the attached membrane were recorded at constant intracellular voltage using whole-cell patch clamp.
We succeeded in capacitive gating of rNaV1.4 channels. The evoked sodium current was sensitive to pharmacological agents LqhαIT (slowed inactivation) and TTX (channel blocking). Numerical simulations were in good agreement with the experiments. However, sufficient coupling strength required an electrolyte with rigorous reduced conductance.