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A Whisker Stimulator For Sensory System Research

Reymond Clavel, Raphael Holzer, Madeleine Kägi

L'outil, le "whisker stimulator" doit permettre de simuler les mouvements naturels des moustaches tout en mesurant simultanément l'activité cérébrale de la souris. Le cahier de charges demande un stimulateur pouvant faire une impulsion de 100um de déplacement à 1kHz. Dans le cadre de ce travail, différentes solutions sont recherchées. Le choix de l'actionneur est un piézotube à quatre segments.

2005

Fabrication of flexible, implantable microelectrodes with embedded fluidic microchannels

Raphael Holzer, Stefan Metz, Philippe Renaud

This paper describes the fabrication of polyimide-based microelectrodes with embedded fluidic microchannels. The thin-film structures combine for the first time a fluidic system with microelectrodes for recording and stimulation of biological signals on a flexible, implantable substrate. Microchannels were realized by a modified lamination technique and combined with a polyimide- platinum-polyimide sandwich structure. The probes can be used for monitoring cellular responses to various chemical stimuli delivered with high spatial precision.

2001

Microelectrodes with three-dimensional structures for improved neural interfacing

Daniel Bertrand, Marc Olivier Heuschkel, Raphael Holzer, Stefan Metz, Philippe Renaud

This paper describes the development of microelectrodes with integrated three-dimensional electrode structures. The integration of three-dimensional structures aims at an improvement of the electrode/tissue interface. Due to the increase in surface area the electrode impedance is reduced, while the density of microelectrodes per area remains the same as with flat electrodes. Two different types of electrodes have been developed: Flexible, implantable microelectrodes with pyramidal, protruding structures and tip-shaped electrode arrays on glass substrates. The protrusion heights of the electrode sites can easily be adjusted depending on the actual application. For the flexible structures we used a polyimide-based process to fabricate microelectrodes with sharp or flat pyramidal tips and with electrode arrangements on front and backside of the devices. The tip-shaped electrode arrays were fabricated from a glass substrate by isotropic wet chemical etching and subsequent metallization and passivation. Data from impedance measurements and acute brain slice recordings indicate a considerable improvement regarding electrode impedance and obtainable signal strength.

2001