Date of Award

May 2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Committee Member

Leah Casabianca

Committee Member

Jason McNeill

Committee Member

Stephen Creager

Committee Member

Brian Dominy

Abstract

NMR is well known for its strong ability to detect the structure of chemicals and has been widely used in many science and engineering areas. As a useful analysis tool, NMR has been combined with nanoparticle to reveal many important factors related to nanoparticle applications. NMR techniques have been used for protein-nanoparticle interaction measurement, nanoparticle size measurement. Nanoparticle, on the other hand, can also improve the development of NMR technology. At present, there are still many open questions stayed in NMR working in nanoparticle research areas and need further studies.

In this dissertation, the thesis stated here will focus on two main objectives. The first one is to combine an advanced NMR technology with polystyrene nanoparticle to make a nanoparticle-based novel polarizing agent, which will enhance the intensity of NMR signals. Dynamic nuclear polarization is one of NMR-related technology which can transfer huge electron polarization to coupled sample nuclei and thus increase the NMR signal intensity. The selection of polarizing agent is a key factor in a successful DNP experiment. Based on free radical α, γ-Bisdiphenylene-β-phenylallyl (BDPA) and polystyrene nanoparticle, we have made an inexpensive polarizing agent in experiments that can be used in water-soluble analytes.

The second part of this thesis interests in the surface interaction of small molecules with polystyrene nanoparticle via noncovalent binding. 1H NMR and saturation transfer difference NMR have been used for the detection of nanoparticle-molecules interaction at an atomic level. As one of NMR technology, saturation transfer difference NMR relies on

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the selective saturation onto receptor protons by irradiating the certain spectral region of receptor protons which is also far from ligand protons signal region. Due to the spin diffusion, saturation will quickly spread across the entire receptor. If ligand molecules bind to the surface of receptor, saturation will also spread onto the ligand molecules, which can attenuate the ligand signal intensity and display in saturation transfer difference spectrum. Briefly, only signals from interacted ligand will be observed after the experiment. In this part, interacted molecular structure from amino acids will be evaluated when binding with polystyrene nanoparticle surface, the binding of more complicated infrared dye molecules IR-783 will also under discussion.

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