Term of Award

Spring 2016

Degree Name

Master of Science in Applied Physical Science (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Chemistry

Committee Chair

Li Ma, Clayton Heller, Hans-Joerg Schanz, Jonathan Arambula

Committee Member 1

Hans-Joerg Schanz

Committee Member 2

Jonathan Arambula

Committee Member 3

Clayton Heller

Committee Member 3 Email

cheller@georgiasouthern.edu

Abstract

Purified Bovine Stroma-Free Hemoglobin’s (BSFHb) two β subunits where intramolecularly cross-linked (BXLHb) using bis(3,5-dibromosalicyl) fumarate (DBBF) and further modified with Polyethylene glycol (BPEGXLHb) for possible use as a Hemoglobin Based Oxygen Carrier (HBOC). Each stage of modification was characterized by size exclusion chromatography, fluorescence as well as MALDI-ToF MS and SDS-PAGE methods. We prepared several different molar ratios of DBBF and BSFHb to acquire the highest yield of BXLHb. Cross-linking of the β subunits will stabilize the whole Hb tetramer from dissociation and prevent unwanted degradation of the HBOC. We prepared BXLHb modified with PEG (PEGylation) that had a molecular weight of 5.5kDa to produce BPEGXLHb. PEGylation increases the total molecular weight of the HBOC which increases the oncotic pressure while the molecule is in the circulatory system. We also tested the oxidative stress stability of each stage of modification through hydrogen peroxide challenge. Different concentration ratios of hydrogen peroxide and reaction duration for each HBOC were observed for dissociation, degradation and Fe3+ formation was monitored using UV-Vis absorbance and electron paramagnetic resonance (EPR). The data showed that modification of cross-linking the β subunits (BXLHb) and BPEGXLHb were very stable compared to BSFHb. Although it was observed that the BXLHb modification alone showed a bit more stability than that of the BPEGXLHb, PEGylation is still an essential modification that allows the HBOC to have the proper oncotic pressure and size to remain in the circulatory system where is can function and provide the necessary benefit of carrying oxygen to tissue.

Research Data and Supplementary Material

Yes

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