Document Type

Thesis

Date of Award

Fall 12-31-2017

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering

First Advisor

Mesut Sahin

Second Advisor

Treena Livingston Arinzeh

Third Advisor

Antje Ihlefeld

Abstract

Multi-channel micro electrodes for neural recording is a growing field that thrives on novel materials and fabrication techniques offered by micro fabrication technology. The material and the design of microelectrodes have a critical role on the quality of neural signals recorded. The neural signals collected by chronic implantation of these devices in experimental animals reveal new information about the brain functions and guide the development of new diagnostic and treatment options for neurological disorders.

Ideally, a microelectrode should meet two important criteria: longevity after implantation and minimal tissue insult. Carbon fibers` high tensile strength and flexibility allow fabrication of micro-scale electrodes that can withstand mechanical challenges in mobile parts of the CNS. Although there are studies showing carbon fibers’ superior qualities as a potential electrode material, these studies are mostly restricted to the brain cortex. There is a need for microelectrode designs that can survive long implantation times in the moving parts of the CNS like the spinal cord.

In this study, carbon fiber microelectrode (CFME) bundles were developed and tested in the spinal cord of experimental animals for neural recording. Neural data analysis revealed that desheathing the tips of the fibers decreased spike counts, but increased signal-to-noise ratios. Triple carbon fibers in parallel did not improve the signal quality as much as desheathing. Lastly, immunohistochemistry showed that electrode tips were splayed in tissue after implantation and each had a small footprint with mild encapsulation around. These results are very promising for the use of carbon fiber bundle electrodes for chronic neural recording in survival studies.

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