High Surface Area Electrodes for Neurostimulation of the Retina
| dc.contributor.advisor | Alemán, BenjamÃn | |
| dc.contributor.author | Zappitelli, Kara | |
| dc.date.accessioned | 2020-12-08T15:45:55Z | |
| dc.date.available | 2020-12-08T15:45:55Z | |
| dc.date.issued | 2020-12-08 | |
| dc.description.abstract | Retinal degenerative diseases (RDDs), which cause the gradual death of rods and cones in the retina, impact millions of people all over the world, yet there are few clinically viable treatments and no cure. Multi-electrode array (MEA) - based retinal implants have emerged over the last two decades as a viable treatment option for those blinded by RDDs. Small electronic implants placed within the degenerate retina are able to restore vision to blind patients, however restored visual acuity (VA) is currently low. To provide patients with useful, high-resolution vision, electrode sizes must be decreased and the density of MEAs increased. As sizes decrease, small electrodes must pass increasingly more charge per unit area in order to provide enough current to stimulate the remaining retinal circuitry. The amount of charge needed often exceeds well-established safety limits that prevent electrode degradation and tissue damage. In order to safely provide enough current to the tissue, one aims to maximize electrode capacitance - the amount of charge an electrode can store for use in stimulation - by increasing the overall surface area without increasing the electrode footprint. In this dissertation, I approach surface area enhancement from the microscale and the nanoscale. I first investigate how micro-patterning of electrode geometry with a fixed footprint can increase stimulation capability. I utilize an electric force microscopy (EFM) characterization technique to compare multiple different microscale electrode geometries. I then introduce vertically aligned carbon nanotubes (VACNTs) grown with chemical vapor deposition (CVD) as an ideal high surface area electrode material. I demonstrate VACNT biocompatibility with retinal neurons in vitro and show that high aspect ratio VACNTs can be integrated with silicon microfabrication processes to create an in vivo platform for rodent studies. Finally, I present work towards integrating these two approaches to create the next generation of high surface area retinal implant electrodes. Taken as a whole, this work offers promise for improving retinal neuron stimulation and restoring high VA to blind patients. This dissertation includes previously published co-authored material. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/25888 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | All Rights Reserved. | |
| dc.title | High Surface Area Electrodes for Neurostimulation of the Retina | |
| dc.type | Electronic Thesis or Dissertation | |
| thesis.degree.discipline | Department of Physics | |
| thesis.degree.grantor | University of Oregon | |
| thesis.degree.level | doctoral | |
| thesis.degree.name | Ph.D. |
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