자료유형  

 학위논문

Control Number  

0017165126

International Standard Book Number  

9798346859529

Dewey Decimal Classification Number  

660

Main Entry-Personal Name  

Ruckodanov, Dmitriy Alexander.

Publication, Distribution, etc. (Imprint  

[S.l.] : University of California, Los Angeles., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

179 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-06, Section: B.

General Note  

Advisor: Monbouquette, Harold G.

Dissertation Note  

Thesis (Ph.D.)--University of California, Los Angeles, 2024.

Summary, Etc.  

요약The development of highly sensitive and selective neurochemical sensors is crucial for advancing our understanding of neurotransmitter dynamics and their roles in neurological disorders. This dissertation focuses on the creation of next-generation electrochemical sensors for dopamine (DA) and γ-aminobutyric acid (GABA), employing innovative surface chemistry, nanostructured materials, and directed evolution techniques.Dopamine is a critical neurotransmitter involved in the regulation of motivation, cognition, and motor behavior. Dysregulation of DA transmission is linked to various central nervous system (CNS) disorders, including Parkinson's disease, schizophrenia, and substance abuse. This research enhances DA sensing by integrating an on-probe iridium oxide (IrOx) reference electrode onto an implantable microelectrode array (MEA) microprobe. The inclusion of IrOx REs on-probe provides potentially significant advantages over traditional, independent Ag/AgCl REs, such as improved stability, reduced inflammatory responses, and lower baseline noise. This post-fabrication electrochemical deposition of IrOx onto targeted microelectrodes enabled high sensitivity DA sensing with an ultralow limit of detection and high selectivity against common electroactive interferents. Comparative studies demonstrated that the integrated three-electrode configuration exhibited a five-fold lower limit of detection (~9 nM) due to an 82% reduction in baseline noise compared to sensors with separate Ag/AgCl REs. These advancements made these DA sensing microprobes highly attractive for in vivo applications, facilitating the study of nervous system disorders through improved DA monitoring.To address the public health crisis of opioid abuse, a partnership was formed with several research labs to develop a high-throughput, multi-organ microphysiological system (MPS) using human induced pluripotent stem cell (iPSC)-derived, midbrain-fated dopamine (DA) and GABA neurons. These MPSs or "brain-on-a-chip" systems, incorporating microglia, a mock blood-brain barrier (BBB), and liver metabolism components, recapitulate the neurobiology of addiction. The aforementioned dopamine sensors with integrated IrOx reference electrodes were successfully integrated into the MPS design to monitor DA release in cultured neurons. However, challenges with media selection-stemming from the differing requirements of liver cells and neurons-and the lack of a reliable protocol for maintaining neuronal viability and sterility within the chips initially limited the system's overall functionality. These limitations highlighted the need for continued optimization of the MPS platform, which remains a promising avenue for future studies aimed at comprehensive drug screening and investigating the mechanisms underlying opioid-induced changes in DA response.γ-Aminobutyric acid (GABA) is the most important inhibitory neurotransmitter in the mammalian brain, playing a vital role in maintaining the excitatory/inhibitory (E/I) balance. Dysregulation of this balance is associated with a range of neurological conditions, including seizures, autism, and traumatic brain injury, which affect millions of people in the US. Despite its importance, high-performance methods to monitor GABA signaling at the cellular level and in near-real-time have been slow to emerge, especially for deep brain regions. Our project aimed to engineer a GABA oxidase suitable for creating a high-performance, implantable, electroenzymatic GABA microsensor. The absence of a commercially available GABA oxidase necessitated the use of directed protein evolution to develop an enzyme with high activity and selectivity for GABA. Our approach involved cloning and expressing a naturally occurring enzyme with native oxidase activity for methyl-GABA, which showed modest activity with GABA. Through advanced ultrahigh throughput techniques, an enzyme was evolved for enhanced utility in GABA biosensors. The enzyme-catalyzed oxidation of GABA produced H₂O₂, which was subsequently electrooxidized at the underlying electrode, providing a current signal correlated to GABA concentration. Promising prototype biosensors demonstrated modest sensing capabilities, and further development and testing for in vivo models is ongoing.This dissertation contributes significantly to the field of neurochemical sensing by addressing the critical needs for low noise, low detection limits, and high selectivity in neurotransmitter biosensors. The integration of innovative materials and techniques will facilitate the development of practical, high-performance sensors for both dopamine and GABA, with potential applications in neuroscience research and clinical diagnostics. These advancements promise to enhance our understanding of complex brain systems and improve the study and treatment of various neurological disorders.

Subject Added Entry-Topical Term  

Chemical engineering.

Subject Added Entry-Topical Term  

Bioengineering.

Subject Added Entry-Topical Term  

Biochemistry.

Subject Added Entry-Topical Term  

Pharmacology.

Subject Added Entry-Topical Term  

Neurosciences.

Index Term-Uncontrolled  

Directed evolution

Index Term-Uncontrolled  

Dopamine

Index Term-Uncontrolled  

Electroenzymatic sensors

Index Term-Uncontrolled  

Fluorescence-activated cell sorting

Index Term-Uncontrolled  

γ-aminobutyric acid

Index Term-Uncontrolled  

Iridium oxide

Added Entry-Corporate Name  

University of California, Los Angeles Chemical Engineering 0294

Host Item Entry  

Dissertations Abstracts International. 86-06B.

Electronic Location and Access  

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Control Number  

joongbu:657727