Document Type

Dissertation

Degree

Doctor of Philosophy

Major

Chemistry, Biochemistry

Date of Defense

11-14-2023

Graduate Advisor

Keith J. Stine

Committee

Alexei V. Demchenko

Michael R. Nichols

Chung F. Wong

Abstract

This research focuses on the field of surface nanobioscience, wherein different nanosurfaces that will be used as working electrodes in the electrochemical cell are manufactured and surface modified to understand the critical binding interactions between biologically significant molecules like proteins, carbohydrates, small drug molecules, and glycoproteins. This research is essential if we are to determine whether a synthetic molecule can serve as a therapeutic candidate or diagnose a disease in its early stages. In order to fully understand the binding interactions, the study begins with defining some of the fundamental concepts, principles, and analytical tools for biosensing.

Afterwards, we addressed a crucial issue in material chemistry: integrating a large surface area with easy molecular movement in the same material. The problem was successfully resolved by developing a hierarchical nanoporous gold (hb-NPG) electrode using the fundamental principles of electrochemistry. An important biomarker for osteoporosis called fetuin A was monitored using square wave voltammetry technique by employing surface-modified hb-NPG as working electrode. The project was advanced by creating a monolith, which has a wide range of industrial applications. The material was created by using the approach of templating and dealloying and was characterized using Brunauer-Emmett-Teller analysis, thermogravimetric analysis, and scanning electron microscopy techniques.

The surface modification process was extended to include other materials like indium tin oxide and Au coated quartz crystal in addition to NPG and hb-NPG. It was critical to comprehend the affinities of synthetically produced compounds with membrane proteins implicated in the transmission of the disease to investigate their potential as therapeutic candidates against a particular disease. Lipopolysaccharide antagonists (such as AM12 and compounds with a lactone structure) and curcumin analogs are examples of synthetic compounds used in this investigation. Lipid binding protein (LBP), Cluster of differentiation 14 (CD14), and Myeloid Differentiation factor 2 (MD-2) are the key proteins in sepsis, and in this study, we examine how well they attach to the LPS antagonists. Receptor Binding Domain (RBD) and Angiotensin Converting Enzyme 2 (ACE2) are another set of proteins that are investigated that are important in covid and explored for their binding affinity towards curcumin analogs.

We created platforms with immobilized proteins to test these drugs' binding affinities for membrane proteins. To observe the outcome of the interaction, various sensing techniques including Quartz Crystal Microbalance, Electron Impedance Spectroscopy, and fluorescence have been employed. The solubility and stability of curcumin analogs were also explored before exploring their binding potential. As seen using UV-vis spectrophotometry, the presence of sugar units in the side chain boosted their hydrophilicity and stability.

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