 Tissue-Engineered Electronic Nerve Interfaces (TEENI): Improved Design, Fabrication, and Packaging Using Automated Aggressive in vitro Reliability Testing Ladan Jiracek-Sapieha and Kenneth Fluker Authors: Ladan Jiracek-Sapieha, Kenneth Fluker, Eric Atkinson, Mary Kasper, Christine Schmidt, Carlos Rinaldi, Kevin Otto, Jack Judy Faculty Mentor: Jack Judy, PhD College: College of Engineering Department: Electrical and Computer Engineering |
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AbstractPeripheral neural interfaces (PNIs) for amputees should reliably capture the activity of motor neurons and stimulate activity in sensory neurons for the lifetime of the patient. Existing implants typically fail within months to a few short years. In order to achieve lasting success with PNIs, the must be engineered to properly interface with tissue and be rigorously tested to mitigate in vivo failure mechanisms. Our hybrid tissue-engineered electronic nerve interface (TEENI) consists of multi-electrode polyimide-based “threads” embedded into a biodegradable hydrogel composite scaffold that is wrapped in a bioresorbable small intestinal submucosa and sutured to the ends of a transected nerve. We have found that first-generation TEENI devices are susceptible to failure and can exhibit a consistent foreign-body response around the microelectrode threads. Herein, we report on design modifications to the TEENI microelectrodes and the use of aggressive in vitro reactive-accelerated aging (RAA) to facilitate rapid fabrication-process improvements of the device and the back-end packaging to better withstand the harsh implant environment. Improved silicone encapsulation was found to be more resistant to this degradation and the resulting explants (3-months, rat sciatic nerve, n = 3) showed no signs of failure. Lastly, we are exploring the use of TEENI microelectrodes with reduced cross-sectional areas to reduce bending stiffness and foreign-body response. We are also using RAA to validate the robustness of the dimensionally reduced devices in preparation for in vivo implantation.
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Poster
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