A MEMS-based fully-integrated wireless neurostimulator

We report design, fabrication and in-vivo animal testing of a MEMS-based wireless battery-free compact (3.1 × 1.5 × 0.3 mm) neurostimulator for the treatment of chronic pain. The neurostimulator consists of a spiral coil for inductive power coupling, Schottky diodes for rectification, an ASIC neurostimulator circuit chip, and biphasic platinum-iridium (PtIr) stimulation electrodes. The device is fully integrated and completely embedded in biocompatible SU-8 packaging. The wireless neurostimulator was implanted subcutaneously in a rat hind limb and stable and robust cortical responses during extended periods of wireless stimulation with as low as 21 dBm (125 mW) RF power at 394 MHz were recorded.