(437d) Improving Cochlear Implant Performance by Directing Nerve Growth with Photopolymerized Micropatterns

Cochlear implants (CIs) provide auditory perception to individuals with severe to profound hearing impairments, however, CI performance has not significantly improved in recent years due to electrical current spread in the inner ear. A neural tissue engineering approach that guides nerve cell processes towards target electrodes may reduce the problematic current spread and enhance CI performance. Consequently, we are using the spatial and temporal control inherent to photopolymerization methodology to fabricate micropatterned methacrylate polymers that direct nerve cell growth based on substrate topographical cues. Micropatterned substrates are formed in a rapid, single-step reaction by selectively blocking light with glass-chrome, ronchi rule photomasks which have parallel line-space gratings from 2.5-100µm in width. The resultant pattern is a continuous series of parallel ridges and grooves at regular intervals and of various amplitudes that can be used for cellular contact guidance studies. Micro-feature depth is controlled and reproducibly generated from 220±40nm to 16±1.3µm by shuttering the light source at different time steps during the reaction. Regenerative growth of inner ear nerve cells orients to the direction of the micropattern and is strongly dependent on feature size. The ultimate goal of the research is to develop materials that elicit specific nerve cell behavior in order to improve the quality of life for CI patients.