Miniature, Flexible Electronics for Treating Neurological Disorders

Sunday, February 17, 2013
Room 302 (Hynes Convention Center)
Philippe Renaud , Microsystems Lab, LMIS4, Lausanne, Switzerland
Electrical neurostimulation of central or peripheral nervous system is known since a long time and is routinely applied, for example, cochlear implants for restoring sound perception. Electrical stimulation is also used in deep brain stimulation for treating movement disorders, in retinal implant to restore visual perception or in spinal chord implant for pain reduction. The progresses in miniaturization allow the fabrication of soft arrays of miniature electrodes that will open new perspectives for more accurate and local neurostimulation. We have developed technologies that make possible the integration of many electrodes on a flexible substrate and even allow the incorporation of fluidic channel for chemical delivery or sampling.

While large or medium size electrode (diameter > 250µm) electrodes are relatively robust for long-term chronic implantation, small electrode are much less stable. Here, we will show how the transfer of electrical current into cellular tissues happens and explain the fundamental biophysical limitations related to the miniaturization of electrodes. This biophysical modeling has been used, for example, to predict the visual resolution of retinal implants. We will also show how the use of microelectrodes could help in much better efficacy in deep brain stimulation.