Regenerative Ultramicroelectrode arrays for sensory-motor specific interfacing

Project Summary Approximately 4 million amputees globally, a number estimated to grow 200,000 annually. Upper limb amputees traditionally use passive, body powered, or electrically powered prostheses that use surface Electromyographic (EMG) signals from intact muscles in the residual limb for movement, despite the motion artifacts, variability and need of visual and/or surrogate sensory control by the user. Advanced peripheral nervous system (PNS) interfaces have been proposed as a viable mechanism to improve the control by amputees, by reading naturalistic sensory feedback from the robotic prosthetics. Unfortunately, current neural interfaces suffer from common challenges, and electrode failure, signal deterioration over time, EMG contamination and electrical and unstable sensory percepts, including “stings or tingles” remain a challenge. This study is uses two novel strategies designed to increase the selectivity of recording/stimulation at the PNS interface: 1) The use of an innovative regenerative multi-electrode interface with ultra-small recording sites using our recently developed ultra-thin multielectrode array , and 2) incorporation of molecular guidance cues to influence the type of sensory neurons at the neural interface. This selectivity Regenerative Ultramicro Multielectrode Array (RUMEA) is designed to discriminate between motor and cutaneous neural interfacing by combining it with molecular guidance to biologically engineer the content of sensory-motor axons at the electrode interface. Three specific aims are included: In SA1 36-electrode RUMAs, straight and Y-shape devices, will be fabricated and electrochemical and mechanical tested. In SA2 we seek to demonstrate selective recording from motor axons and evoke touch percepts using the RUMA. In SA3, we will demonstrate selective interfacing of motor and tactile axons in an upper limb amputee rat model of bidirectional Nerve Machine Interface using molecularly guided RUMAs. If successful, this strategy will demonstrate the benefit for using RUMA for selective recording from motor axons, and stimulation of sensory modality axons that evoke naturalistic sensory percepts. This advancement in peripheral neural interfaces for amputees, will reduce the cognitive burden for users of robotic prosthetics, and decrease the abnormal sensations associated with electrical stimulation in the PNS.