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Full text release has been delayed at the author's request until December 09, 2024

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Exploiting Carbon Nanotubes and Flexible Polymer Coatings to Address Key Challenges in Biomedical Applications

Ruhunage, Chethani
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703169458977613

Abstract Details

2023, PhD, University of Cincinnati, Arts and Sciences: Chemistry.
Implantable biosensors and neural electrodes serve as essential tools for exploring the brain function, the pathology of brain related disorders, and the development of therapeutic tools like deep brain stimulators (DBS) for conditions like Parkinson’s disease, Alzimer’s disease and epilepsy. Given that these conditions often persist throughout a person’s lifetime, the consistent performance of these devices is critical. To gain insights into the complex nature of these diseases, biosensors and recording electrodes are implanted for extended durations, spanning from days to months. Therefore, these recording devices must ensure the delivery of accurate information over the entire study period. In recent decades, scientists have dedicated substantial efforts to the development of implantable devices, aiming to improve their performance for chronic applications. DBS represents one of the successful outcomes of these efforts. However, developing an ideal neural device is an ongoing challenge due to undesirable interactions with the biological environment upon implantation. The work presented in this thesis seeks to address the enduring challenges in this field and explore the potential of carbon nanotubes (CNTs) in development of neural electrodes, with the goal of improving their performance. This thesis comprises the work of three projects. The first project provides a comprehensive in vitro analysis of an anti-fouling interface based on zwitterionic molecules and CNTs. In this project, we developed an antifouling interface combining zwitterionic molecules and CNTs to reduce the effect of initial inflammatory responses. The developed interface was assessed in vitro using various methods, including spectroscopy, electrochemistry, morphology, and biological testing. Accelerated aging tests were also conducted to assess the stability of the developed interface. The second project describes a continuous dip coating (CDC) technique for developing flexible polymer coatings on CNT fibers. In this project, we address the ongoing need for flexible polymers in the development of neural electrodes. Hydrogenated nitrile butadiene rubber (HNBR) was evaluated for the first time as an insulation material for neural electrodes. The coating technique was studied with a focus of achieving uniform and pinhole-free coatings. A comprehensive analysis was conducted under in vitro conditions to evaluate the HNBR polymer, for its eventual use in vivo. Testing included assessments of chemical, electrochemical, morphological, accelerated aging, and in vitro cytotoxicity. The third project in this thesis describes a method for chemically attaching CNTs with Pt surfaces to improve the electrochemical properties of Pt metal. This project describes the conventional approaches of depositing CNTs on metal electrodes and highlights the instability of modified metals due to desorption of CNTs over time. It also emphasizes the necessity of chemical bonding between CNTs and metals to ensure uninterrupted charge transfer at the metal-CNT junction. The project includes a comprehensive evaluation of the chemical, electrochemical, and morphological evaluation of the developed CNT-Pt interface. Furthermore, we evaluated the stability of the modified CNT-Pt substrates under extreme conditions. The method developed in this project is subsequently applied to the modification of Pt-based microelectrode arrays addressing both improvements and challenges encountered in the process.
Noe Alvarez, Ph.D. (Committee Chair)
Ashley Ross, Ph.D. (Committee Member)
Elke Buschbeck, Ph.D. (Committee Member)
158 p.
Analytical Chemistry
Neural interfaces; Carbon nanotubes; Flexible polymer coatings; Microelectrode arrays

Recommended Citations

Citations

  • Ruhunage, C. (2023). Exploiting Carbon Nanotubes and Flexible Polymer Coatings to Address Key Challenges in Biomedical Applications [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703169458977613

    APA Style (7th edition)

  • Ruhunage, Chethani. Exploiting Carbon Nanotubes and Flexible Polymer Coatings to Address Key Challenges in Biomedical Applications. 2023. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703169458977613.

    MLA Style (8th edition)

  • Ruhunage, Chethani. "Exploiting Carbon Nanotubes and Flexible Polymer Coatings to Address Key Challenges in Biomedical Applications." Doctoral dissertation, University of Cincinnati, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703169458977613

    Chicago Manual of Style (17th edition)

ucin1703169458977613
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This open access ETD is published by University of Cincinnati and OhioLINK.