Development of a Microdialysis Probe with Multichannel Microelectrodes

Abstract

To advance understanding of the mechanisms of neural interactions, including complex electrical and biochemical reactions, we designed and fabricated a microdialysis probe with multichannel neural electrodes for simultaneously recording both electrical and chemical neural signals. The microelectrodes were fabricated on the curved surface of the guide cannula of the microdialysis probe by using micro-electro-mechanical systems technologies. The advantage of placing microelectrodes on the guide cannula is that, like conventional microdialysis probe, the part of membrane in the microdialysis probe can be removed and replaced without further surgery to the animal, depending on an experimental design or in the case of mechanical failure of the membrane. Because of difficulty in controlling the etching conditions to expose the microelectrodes, we applied only a wet process for this fabrication with photosensitive polyimide and electrodeposition resist. Photosensitive polyimide was used for base and insulated layers. Chromium-gold, patterned with electrodeposition resist as a sacrificial layer, was used for individual recording electrode sites, interconnect lines, and connection pads. In biochemical studies, the fabricated microdialysis probe with multichannel electrodes has satisfied the physical properties of electro impedance and the recovery rate of neural substances, permitting practical use for animal experiments.