A PDMS-based optical waveguide for transcutaneous powering of microelectrode arrays

Implantable microelectrode arrays (MEAs) usually have on-site electronics that need to be powered, both in neural recording and stimulation applications. Interconnecting wires between implanted electrodes and the outside world constitute a major source of complications. Our solution to this tethering problem is to design a light waveguide that can collect the optical power transcutaneously and transmit it to the microelectrode array where it is to be converted to an electric current. A polydimethylsiloxane (PDMS)-based waveguide was fabricated and its attenuation was measured in vitro and found to be 0.36 dB/cm. The skin flap of the thenar web space in the hand was used to test the photon collection efficiency of the waveguide in diffuse light. The efficiency of the waveguide alone was 44±11% (mean±std), excluding the attenuation within the thenar skin, as measured in 13 subjects with different skin pigmentations. These preliminary results suggest that a PDMS waveguide may collect and deliver optical power with sufficient efficiencies to deep structures inside the body. Optical powering scheme can solve the tethering and breakage problems associated with metal wire connections.