Regensburg 2004 – scientific programme

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SYLS: Life Sciences on the Nanometer Scale - Physics Meets Biology

SYLS 3: Symposium "Life Sciences on the Nanometer Scale - Physics Meets Biology"

SYLS 3.32: Poster

Wednesday, March 10, 2004, 16:00–18:30, B

SILICON-ON-INSULATOR BASED THIN FILM RESISTOR FOR CHEMICAL AND BIOLOGICAL SENSOR APPLICATIONS — •Michael G. Nikolaides, Simon Q. Lud, Petra Neff, Stephan Rauschenbach, and Andreas R. Bausch — Lehrstuhl für Biophysik - E 22, TU München, 85747 Garching, Germany

The understanding of the dynamics of biomolecular interactions is one of the main challenges for future biophysical research. Recently, there have been several approaches emerging for label-free detection techniques. Very promising surface sensitive techniques, which are envisioned, are impedance spectroscopy, ellipsometry or force spectroscopy.

We present a novel surface sensitive technique based on commercially available silicon on insulator (SOI) substrates. By very sensitive electrical transport measurements we are able to detect the change of the surface potential which results in a change of the conductance parallel to the surface. An applied back gate voltage enables us to control the sensitivity of the sensor layer.

We present the detection of pH and electrolyte concentration with the bare silicon oxide surface. We get good agreement with the theoretical predictions of the Grahame equation and the site binding theory. The adsorption of polyelectrolytes on the oxide surface can be used to estimate the sensitivity of the device to be 1e-/40nm2.

Furtheron, we discuss first results of a lipid membrane based charge sensor on the SOI device and discuss the aplication of the developed system towards the specific recognition of poteins.