Publications de Olof Pontus Linderholm

Long-term in vivo impedance changes of subretinal microelectrodes implanted in dystrophic P23H rats

Retinal prostheses are being developed to restore vision in blind patients with photoreceptor degeneration. Electrodes arrays were subretinally implanted in transgenic P23H rats with their photoreceptors degenerated. Electrical stability of the implants wa ...

Wichtig Editore2013

Cell culture imaging using microimpedance tomography

Philippe Renaud, Olof Pontus Linderholm

We present a novel, inexpensive, and fast microimpedance tomography system for two-dimensional imaging of cell and tissue cultures. The system is based on four-electrode measurements using 16 planar microelectrodes (5 mum x 4 mm) integrated into a culture ...

2008

Characterization and optimization of liquid electrodes for lateral dielectrophoresis

Philippe Renaud, Thomas Michael Braschler, Harald Van Lintel, Nicolas Demierre, Urban Seger, Olof Pontus Linderholm

Using the concept of insulator-based "electrodeless" dielectrophoresis, we present a novel geometry for shaping electric fields to achieve lateral deviation of particles in liquid flows. The field is generated by lateral planar metal electrodes and is guid ...

2007

Bipolar resistivity profiling of 3D tissue culture

Philippe Renaud, Yann Barrandon, Olof Pontus Linderholm, Jonas Vannod

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 imped ...

Elsevier2007

Apparatus for manipulating, modifying and characterizing particles in a micro channel

Philippe Renaud, Thomas Michael Braschler, Nicolas Demierre, Urban Seger, Olof Pontus Linderholm

Microfluidic system comprising a space (0207) for containing a liquid and at least one lateral chamber (0201) in communication with said space, said lateral chamber containing a metal electrode (0204). The lateral chamber and the space are designed to be f ...

2007

Retinal Prosthesis : Testing Prototypes on a Dystrophic Rat Retina

Philippe Renaud, Olof Pontus Linderholm, Sri Harsha Kasi Raj

2007

Creating structures at the scale of cells on the fly: gentle single cell entrapment on chip

Philippe Renaud, Thomas Michael Braschler, Nicolas Demierre, Urban Seger, Olof Pontus Linderholm

2007

Two-dimensional impedance imaging of cell migration and epithelial stratification

Philippe Renaud, Yann Barrandon, Thomas Michael Braschler, Olof Pontus Linderholm, Jonas Vannod

We present a miniaturized impedance imaging system, developed for 2D imaging of cell and tissue culture. The system is based on 16 microelectrodes (5 µm × 4 mm). An equivalent circuit for four-point (tetrapolar) impedance spectra was developed and validate ...

2006

Subretinal electrode implantation in the P23H rat for chronic stimulations

Philippe Renaud, Olof Pontus Linderholm

Background: In age related macular degeneration and inherited dystrophies, preservation of retinal ganglion cells has been demonstrated. This finding has led to the development of various models of subretinal or epiretinal implant in order to restore visio ...

2006

Analytical expression for electric filed between two facing strip electrodes in microchannels

Philippe Renaud, Urban Seger, Olof Pontus Linderholm

An analytical solution is presented for the electric field between two facing strip electrodes situated in a microchannel, as frequently used in impedance cytometry applications. The measured change in resistance as induced by a 5 mm bead moving through th ...

2006