Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 13: Cell Adhesion II

AKB 13.2: Talk

Tuesday, March 28, 2006, 14:45–15:00, ZEU 260

The Electrical Noise of Cell-Substrate-Junctions: A New Method to Probe Cell Adhesion — •Moritz Voelker and Peter Fromherz — Max-Planck-Institut für Biochemie, Martinsried

The junction between cultured cell and substrates is filled with electrolyte. The aqueous cleft between membrane and solid has a width of typically 50 nm and a sheet resistance in the order of several Mohm-square. As every electrical resistance, the junction resistance must exhibit Johnson noise in the form of fluctuations of the local voltage with respect to the bulk electrolyte. We report on a measurement of these voltage fluctuations for rat hippocampus neurons on silicon dioxide, using electrolyte-oxide-silicon field-effect-transistors with a particularly low intrinsic noise. We evaluate the spectral power density of the junction noise by subtracting the noise of open transistors from the total noise of covered transistors. In a first approximation, the resulting net power spectrum is fitted with a Lorentz spectrum for an RC equivalent circuit of the cell-chip junction. The novel technique is non-invasive, does not rely on molecular probes and does not require any intra or extracellular stimulation. It allows to detect variations of cell adhesion in real time as induced by external chemical stimuli.