The Fabrication of High Density Neural Implants

One in fifty people in the United States suffer from some form of paralysis.  In the most severe cases, they suffer from full paralysis.  In these situations, their brain is usually functioning, however the neural signals do not reach the limb they intend to move, a neural implant becomes necesary in order to pick up the lost brain signals.  The current technology in this field is functional, however there is room for improvement.  The current neural implant are composed of silicon which is very stiff, and once inserted in to the brain causes the formation of unwanted scar tissue.  Our proposed brain implant, which will be used in a wireless neural recording device is composed of a soft polymer called Polydimethylsiloxane(PDMS).  PDMS is nontoxic to biological systems and is the right stiffness to limit scar-tissue formation with once inserted, however PDMS is non-conducting.  In our research, we created a  conductive high density neural implant composed of a mixture of PDMS and nickel particles 5-50 microns in diameter.  This was achieved by loading the mixture of PDMS and nickel particles into a mold with magnetic guidance, then baking at 150 degrees Celsius and releasing the implant from the mold.  Further research includes optimizing the design of the neural implant so that it will survive insertion. Once optimized, the device will be send to the Univeristy of California San Diego for animal testing.