Date Thesis Awarded

5-2015

Document Type

Honors Thesis

Degree Name

Bachelors of Science (BS)

Department

Chemistry

Advisor

Tyler Meldrum

Committee Member

Shanta Hinton

Committee Member

Gary Rice

Abstract

Identification of molecules in complex mixtures is a fundamental problem in analytical chemistry. NMR is widely used for molecular identification in impure samples, but traditionally is an expensive technique that requires a large-scale laboratory setting and extensive training to operate. New relaxometric techniques have been developed for low-cost NMR apparatuses with strong field inhomogeneities, where change in relaxation time T2 of water surrounding the aggregation of paramagnetic nanoparticles around a given analyte is measured. These devices’ strong magnetic field gradients make them suitable for simultaneous measurement of the self-diffusion constant D. In this study, the advantages of a two-dimensional T2-D approach to molecular identification of a protein-specific ligand analyte in complex with its target protein are assessed as a “proof of principle” experiment. Since complexation reduces molecular motion, we expect both T2 and D will decrease, indicating the presence of the ligand by the shape and size of the sensor as a unit rather than its chemical makeup. Per the complex nature of our selected protein-ligand binding interactions (those of bovine serum albumin and naproxen), the detection of a number of unexpected phenomena, including naproxen self-association, non-specific binding interactions, and possibly rapid chemical exchange are reported. A potential method by which low-field, single-sided NMR devices may be used to determine thermodynamic constants is also demonstrated.

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