Chemistry & Biochemistry Masters Theses

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Browsing Chemistry & Biochemistry Masters Theses by browse.metadata.program "Chemistry"

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    Carbon Nanotubes-Based Lateral Flow Biosensor for Sensitive and Rapid Detection of DNA Sequence
    (North Dakota State University, 2017) Zhang, Xiaoguang
    Sensitive detection for DNA has drawn great attention in plenty of different areas such as genetics therapy and basic discovery research. Recently, nucleic acid lateral flow biosensor (NALFB) has gained considerable attention for DNA analysis. Compared with the traditional immunoassays, NALFB has these advantages: short assay time and a low cost. In this thesis, we report a carbon nanotubes (CNTs)-based NALFB for rapid and sensitive detection of DNA. Amine-modified DNA detection probe was covalently immobilized on the CNTs via diimide-activated amidation between the carboxyl groups on the CNTs surface and amine groups on the detection DNA probes. Sandwich-type DNA hybridization reactions were performed and the captured MWCNTs on test zone and control zone produced the characteristic black bands. Based on the catalytic property of CNTs to enhance the Chemiluminescence intensity of the reaction between hydrogen peroxide and Lumigen APS-5, a rapid detection of DNA sequence with high sensitivity is achieved.
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    Identification of Aptamer Specific for Carcinoembryonic Antigen and its Analytical Applications
    (North Dakota State University, 2017) Lund, Michelle
    Carcinoembryonic Antigen (CEA) is an approved cancer biomarker by the Food and Drug Administration (FDA) for the early detection, diagnosis, and for the use in the regular screening of patients at high risk for the development of cancer. Traditional methods to determine the concentrations of CEA are based on utilizing antibodies. In this project, a graphene oxide (GO)–assisted systematic evolution of ligands through exponential enrichment (SELEX) was used to identify DNA aptamers specific for CEA. The dissociation constants of the identified aptamers were determined with surface plasmon resonance (SPR). Comparison of the dissociation constants of aptamers isolated from the GO-based SELEX and affinity SELEX found the dissociation constant of the aptamers isolated from GO-assisted SELEX was three times lower than aptamers isolated from the affinity SELEX. The analytical applications of the identified aptamers were studied by developing a colorimetric test for the determination of CEA with un-modified gold nanoparticles.
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    Identification of Novel RPA-Protein Interactions Using the Yeast Two Hybrid Assay and Identification of Regions Important for Interaction Between RPA and Rad24
    (North Dakota State University, 2013) Piya, Gunjan
    Replication Protein A (RPA) [Replication Factor A (RFA) in yeast] is an ssDNA binding protein composed of Rpa1, Rpa2, and Rpa3 and involved in numerous DNA processing pathways such as Replication, Recombination, and Repair. It participates in such diverse pathways by its ability to interact with numerous proteins. The goal of my project was to find novel RPA-protein interactions using the yeast two hybrid assay. Using this method, we identified several known and unknown proteins that interact with Rfa1 and showed that these interactions were dependent on the phosphorylation state of Rfa2. Next, we determine the region important for interaction between Rfa1 and Rad24. Rad24 is a checkpoint protein important for initiation of the DNA damage checkpoint signaling. By using the β- galactosidase assay, we determined the N-terminal region of Rfa1 (DBD-F) and the C-terminal region of Rad24 (460-660 aa) to be necessary for their interaction.