Silicon based microstructures suitable for intracortical electrical stimulation (visual prosthesis application)

The authors have produced a 0.4-mm*0.4-mm*1.6-mm, three-dimensional, silicon-based microstructure which can be used for stimulation of cortical neurons. The structure consists of 100 pyramidal-shaped needles, each 1.5 mm long with a base about 0.06 mm on a side. The entire structure is passivated with silicon nitride except for the tips of the needles, which are coated with platinum. The mechanical properties of these structures and the tissue reaction to them were studied in cat cortex. Impact insertion of the arrays produces good implantation with minimal tissue insult. Preliminary histological studies suggest that cortical tissues are not adversely affected by these microstructures.<>