Fabrication, Testing And Modelling Of Multi-contact Deep Brain Stimulation Electrode

Deep brain stimulation (DBS) could be effective for treating some disorders such asepilepsy, Parkinson’s disease, depression. DBS electrode was an important part of DBSsystem. Because the currently available DBS electrode had four larger area contacts andcontact channel was few, the stimulation resolution was low and unnecessary area of braintissue was stimulated meanwhile bringing side effects. How to design and make a kind ofDBS electrode to avoid side effects becomes an important R&D project, which will helpclinical application and the research of brain function in the future.To improve the resolution and precision of the deep brain stimulation, a threedimensional electrode with multi-contact was produced through a MEMS fabricationmethod and a novel moulding process using3-D printing technology. The new electrodeconsisted of24small contacts distributed over the surface of a cylinder with length of20mm and diameter of1.5mm. Each electrode site is0.285mm×1.5mm.The fabrication process includes the following three main steps. In the first step,micro machining techniques were applied for the planar electrode fabrication usingbiocompatible materials Parylene C as the substrate and Au as electrode materialrespectively, which produces a double-sided planar electrode with one side acting asstimulation electrode array and the other as bonding pads. Then a thin Pt wire is weldedonto each pad. Finally, a customized mold is created using3-D printing technique to makethe planar electrode fitted into a cylindrical shape tube. The electrode is then moulded withbio-compatible silicone, and thus a three dimensional electrode is formed. Thecharacteristics of the electrode were visually and physically tested. The electrode has asmooth surface and a distinct outline. The electrical test shows that the electrode has agood quality and excellent electrical properties. The microfabrication technology is suitable for the deep brain stimulation electrodeproduction. This research would provide a basis for flexible circuit integration in the deepbrain stimulation electrode.