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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.77: Poster

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

High-K Coatings on Silicon Chips for Capacitive Stimulation of Cells. — •Frank Wallrapp and Peter Fromherz — Max Planck Institut für Biochemie, Abt. Membran- und Neurophysik, Martinsried, Germany

So far leech and snail neurons were capacitively stimulated with silicon chips that were insulated from electrolyte by a thin layer of SiO₂. To enhance capacitance we replaced SiO₂ by the high-k materials HfO₂ and TiO₂. Capacitance and leakage current were measured in an electrolyte-insulator-silicon (EIS) configuration. Considering leakage current and biocompatibility, HfO₂ and TiO₂ both proved to be suitable for neuronal stimulation. Due to the higher capacitance, however, TiO₂ is superior in applications. We cultured nerve cells from rat hippocampi on TiO₂-coated chips and recorded the intracellular voltage by patch-clamp techniques. Applying bursts of positive voltage pulses to stimulation areas, we could reliably elicit action potentials in the neurons. The new high-k coated chips open up the way to new applications, e.g. opening voltage-gated potassium channels in stably transfected HEK293 cells (Ulbrich & Fromherz, in preparation) and stimulating rat brain slices (Hutzler & Fromherz, in preparation).