The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology

Bibliographic Details
Main Author:	Harris, James Patrick
Language:	English
Published:	Case Western Reserve University School of Graduate Studies / OhioLINK 2011
Subjects:	Biomedical Engineering Brain Neural Prosthesis micromotion cellulose Cell encapsulation electrode Inflammation Mechanical properties Nanocomposite Young&8217 s Modulus Insertion Force
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-case13209504392021-08-03T05:34:10Z The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology Harris, James Patrick Biomedical Engineering Brain Neural Prosthesis micromotion cellulose Cell encapsulation electrode Inflammation Mechanical properties Nanocomposite Young&8217 s Modulus Insertion Force The overall goal of this work is to improve intracortical electrodes for chronic recordings from the brain. The studies in the dissertation examine material stiffness, the tissue response, and electrode recording quality to enable improvements. Intracortical electrodes can improve the quality of life of patients with severe paralysis via brain machine interfaces (BMIs), but factors limit electrode widespread clinical usage. One factor of implanted intracortical electrodes is that the number of recorded signals decreases over time, limiting the longevity of electrodes. The decrease is hypothesized to be from the tissue response to the electrodes. In this dissertation, we investigate the tissue response and its effect on electrode recordings. Specifically, we examine the role of material stiffness on the tissue response. Recently developed, a mechanically adaptive nanocomposite decreases its stiffness from 5 GPa to 12 MPa in vitro. Confirming in vitro work, we show that the nanocomposite is stiff enough for insertion, but softer than traditional BMI electrodes after brain implantation. The nanocomposite enables our examination of the role of material stiffness on tissue response. Implanting the soft nanocomposite and surface-matched stiff microwire, we examine the effect of stiffness on tissue response. At one month, greater neural density around the nanocomposite versus the microwire accompanies changes in mechanically associated factors, intermediate filaments and extracellular matrix components. At two months, the neural densities are similar between implant types, and neural density around the nanocomposite is maintained despite macrophage activation. The soft nanocomposite modifies the tissue response, and therefore, we examine whether the tissue response affects neural recordings. By using lipopolysaccharide (LPS) to promote the inflammatory response, LPS-treated animals show an increase in non-neural cells and a decrease in the neural cells near the implant. Additionally, the quality of recordings is reduced in LPS-treated animals. Though further research is necessary, the results of this work support the hypothesis that a softer material can improve long-term neural recording. The work guides electrode development to improve electrodes to offer patients with severe paralysis and other neurological deficits a better quality of life. 2011 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439 http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Biomedical Engineering Brain Neural Prosthesis micromotion cellulose Cell encapsulation electrode Inflammation Mechanical properties Nanocomposite Young&8217 s Modulus Insertion Force
spellingShingle	Biomedical Engineering Brain Neural Prosthesis micromotion cellulose Cell encapsulation electrode Inflammation Mechanical properties Nanocomposite Young&8217 s Modulus Insertion Force Harris, James Patrick The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology
author	Harris, James Patrick
author_facet	Harris, James Patrick
author_sort	Harris, James Patrick
title	The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology
title_short	The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology
title_full	The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology
title_fullStr	The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology
title_full_unstemmed	The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology
title_sort	glia-neuronal response to cortical electrodes: interactions with substrate stiffness and electrophysiology
publisher	Case Western Reserve University School of Graduate Studies / OhioLINK
publishDate	2011
url	http://rave.ohiolink.edu/etdc/view?acc_num=case1320950439
work_keys_str_mv	AT harrisjamespatrick theglianeuronalresponsetocorticalelectrodesinteractionswithsubstratestiffnessandelectrophysiology AT harrisjamespatrick glianeuronalresponsetocorticalelectrodesinteractionswithsubstratestiffnessandelectrophysiology
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The Glia-Neuronal Response to Cortical Electrodes: Interactions with Substrate Stiffness and Electrophysiology

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