Eur. Phys. J. E (2009) 30: 233-238
https://doi.org/10.1140/epje/i2009-10511-x

Regular Article

Gallium nitride electrodes for membrane-based electrochemical biosensors

¹ Institut für Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
² Walter Schottky Institut, Technische Universität München, Am Coulombwall, 85748, Garching, Germany
³ I. Physikalisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany

^* e-mail: tanaka@uni-heidelberg.de

Received: 11 March 2009
Revised: 27 April 2009
Accepted: 10 June 2009
Published online: 3 September 2009

Abstract

We report on the deposition of planar lipid bilayers (supported membranes) on gallium nitride (GaN) electrodes for potential applications as membrane-based biosensors. The kinetics of the lipid membrane formation upon vesicle fusion were monitored by simultaneous measurements of resistance and capacitance of the membrane using AC impedance spectroscopy in the frequency range between 50mHz and 50kHz. We could identify a two-step process of membrane spreading and self-healing. Despite its relatively low resistance, the membrane can be modeled by a parallel combination of an ideal resistor and capacitor, indicating that the membrane efficiently blocks the diffusion of ions.