Regensburg 2004 – scientific programme

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.76: Poster

Friday, March 12, 2004, 10:30–13:00, B

Electrical Coupling of Lipid Vesicles to Silicon Chips — •Christian Figger and Peter Fromherz — Max-Planck-Institute for Biochemistry, Department of Membrane- and Neurophysics, Am Klopferspitz 18a, 82152 Martinsried

We developed a method to contact giant vesicles with microelectrodes and studied their electrical coupling to silicon chips.

Electrophysiological recordings were achieved by a combination of three techniques: (i) Fixation of the vesicles by plastic cages. (ii) Coating of the microelectrodes. (iii) Verifying the contacts by fluorescein injection. The contacts originated mostly from rolling membranes. Seal resistances reached the gigaohmic range and declined during a maximum period of half an hour.

The novel method was applied to measure the signal transmission from the vesicle into an array of field-effect-transistors. An electrolyte with a very high resistance was used to improve the transmission between vesicle and chip. Two results were obtained: (i) The conductance of the adherent membrane was much higher than expected. This may result from the membrane tension or the albumin coating of the chips. (ii) The resistance of the electrolyte in the gap between vesicle and chip was much lower than in the bath. The diffuse double layer on the chip surface may account for this.