Flexible multichannel-stimulator for motor neuroprosthesis in vivo by remotely driven in vitro

Motor neuroprosthesis, which can improve motor recovery of patients with central nervous system diseases by activating paralyzed or paretic muscles using functional electrical stimulation (FES) technology, is a promising electronic device in the rehabilitation engineering. The most of implantable motor neuroprosthesis are powered and controlled by external electromagnetic field. However, the energy transmission distance, flexibility and miniaturization as well as the demands for simultaneous multichannel stimulation remain the great challenges for implantable motor neuroprosthesis. On account of the excellent bio-friendly performance and well penetration to tissue of near-infrared ray (nIR), we construct a flexible multichannel stimulator that can be implantable and remotely controlled by nIR in vitro. The proposed stimulator contains several independent channels (4 channels in our experiments, and can be extent to more channels) are fabricated on the same piece of functional layer, ensuring the compactness and the performance conformity of the stimulator. To enhance the output voltage/current and the controllability of the multichannel FES, designed micropatterns on each channel are introduced by a laser machining process to ensure the precision of the micropatterns on each channel as well as the relative positions among the channels. Experiments reveal that, the proposed stimulator can generate voltage/current for FES in each channel simultaneously by responding to one nIR beam remotely, providing a multichannel stimulation for nerves of a frog and resulting in the controllable muscle contraction. The nIR-driven implantable multichannel stimulator supplies a promising method for motor neuroprosthesis, which may find applications in motor neuron disease treatment and rehabilitation engineering.