Biomolecules function only in aqueous environments and their dynamics are strongly influenced by physiological conditions including the temperature and the presence of co-solutes. The presence of biomolecules in aqueous solutions will change the dynamics and structure of water, and as a response, water will form hydration layers around biomolecules. The dynamics of hydration water, as well as hydrated proteins, lead to translation, rotation, and oscillating dipoles that, in turn, give rise to absorption in the megahertz-to-terahertz frequencies. However, the strong absorption of water in this frequency range leads to a significant challenge in obtaining terahertz dielectric spectra of aqueous biomolecular solutions. In response, I have employed a high sensitivity terahertz frequency-domain spectroscopy to overcome these issues on a large range of frequencies from 10 MHz to 1.12 THz. The high dynamical range of the system combined with a variable-path-length cell allows precise measurement of the complex dielectric response of the solutions. Employing Debye and Lorentzian approximations, I have decomposed contributions of the dielectric response of the solutions. The structure and dynamics of hydration shells and hydrated biomolecules have been identified. Performing experiments on a number of biomolecules have verified the certainty of the methods, thus, enriching the knowledge of the biological science of dynamics and functions of biomolecules. / Doctor of Philosophy / Biomaterials are essential for life, including all elements present in cells and organisms, and contribute to the living biological processes. Biomaterials, consisting of a diverse range of biomolecules, have traditionally been characterized in a wide range of approaching methods based on biological, chemical, and physical methodologies. This study investigates the molecular dynamics of biomolecules in native living environments to explore physics- and mechanics-based insights into their biological functions. Biomaterials together with water molecules perform their functions through molecular translations, rotations, and collective motions. To explore these dynamics, a home-built terahertz spectroscopy with high sensitivity has been utilized to characterize the dynamics of biomolecular aqueous solutions in the frequency range from megahertz to terahertz. The collected complex dielectric responses of the solutions have been examined through physical models to map out structures and dynamics of hydration shells and, then, the dynamics of hydrated biomolecules have been determined. The successfully investigating results in the dynamics of solvents from three different types of proteins and ionic solutions reveal critical information on hydrated biomolecular dynamics and biomolecule–water interactions, which impact the biochemical functions and reactivity of biomolecules.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/109719 |
| Date | 21 April 2022 |
| Creators | Doan, Luan Cong |
| Contributors | Mechanical Engineering, Nguyen, Vinh, Vick, Brian, Qiao, Rui, Mahan, James R. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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