title: Bipolar resistivity profiling of 3D tissue culture.
abstract: We describe a new low-cost technique for continuous monitoring of the thickness of biofilms and tissue cultures, and we demonstrate the advantage of using electrodes of different dimensions to probe different depths of a sample. We have used electric impedance spectroscopy to monitor keratinocyte stem cells (YF29) growing on an array of Ti/Pt coplanar microelectrodes. The thickness of the sample was reconstructed by fitting the measurements to theoretical curves. We have developed an algorithm for the rapid calculation of the resistance through a multilayered sample. This algorithm is based on conformal mapping and the serial partial capacitance technique. The validity of the technique was tested by measuring the sedimentation rate of an alumina powder. Sample thicknesses between 10 and 80 microm could be measured with a resolution of a few microns using the device.
authors.affiliation: Microsystems Laboratory, Swiss Federal Institute of Technology, 1015 Lausanne, Switzerland. pontus.linderholm@epfl.ch
authors.forename: Pontus
authors.initials: P
authors.lastname: Linderholm
authors.forename: Jeanne
authors.initials: J
authors.lastname: Vannod
authors.forename: Yann
authors.initials: Y
authors.lastname: Barrandon
authors.forename: Philippe
authors.initials: P
authors.lastname: Renaud
mesh_terms: D001681:Biological Assay / Q000295:instrumentation / Q000379:methods*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002460:Cell Line; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D015603:Keratinocytes / Q000502:physiology*; D008839:Microelectrodes; D010992:Plethysmography, Impedance / Q000295:instrumentation / Q000379:methods*