Doctor of Philosophy (PhD)
Fluorescence methods for disease diagnosis and detection of important analytes are becoming popular route as a technique, as they offer a simple non-invasive approach. Recently, many novel fluorophores and probes have been reported for selectively and sensitively detecting low abundance biological species in disease pathways. Biological thiols, such as glutathione, cysteine, and homocysteine, along with the smallest member hydrogen sulfide, are key thiol analytes in biological environments, and they play a vital role in living systems by maintaining the redox homeostasis of cells. Alteration of their ratios can cause cellular dysfunction and cell death. Furthermore, thiol levels in cells and biological fluids act as biomarkers of several diseases, including neurodegenerative disorders, liver disease, cystic fibrosis, pulmonary and cardiovascular diseases, and Alzheimer’s disease. Thus, the development of efficacious methods for detection and quantification of biological thiols has received significant attention in recent years. Although many traditional thiol detection methods are available, fluorescent methods hold more promise for simple, non-invasive detection with simple instrumentation. The work presented in this dissertation discusses the successful fluorescent detection of biologically important thiols with two probes HMBQ-Nap 1 and DCM-Cys. The HMBQ-Nap 1 probe consists of a hydroxymethyl benzoquinone trigger group (HMBQ) and 4-amino-9-(n-butyl)-1,8-naphthalimide (Nap 2) as the reporter dye. This probe led to excellent class selective detection of the free thiols glutathione, cysteine, and homocysteine versus other analytes found in the body. The second probe, DCM-Cys, is composed of a cysteine-selective acrylate moiety attached to dicyanomethylene-4H-pyran (DCM) reporter dye via a benzyl alcohol linker. DCM-Cys exhibited a remarkable ability to detect free cysteine in media versus other thiols and various potent analytes found in biological environments. Both HMBQ-Nap 1 and DCM-Cys offer nM in vitro detection, and successful in cyto imaging of thiols. Selectivity, a relative low limit of detection (nM), the ability to function under physiological conditions and a high signal-to-background ratio of these methods as well as low thiol-to-probe ratios for the qualitative and quantitative detection, and relatively short response time make these probes excellent systems for thiol analysis.
Document Availability at the Time of Submission
Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.
Nawimanage, Rasika Ranatunga, "Synthesis, Characterization, and Evaluation of Small Molecule-based Fluorogenic Probes for the Detection of Cellular Thiols" (2015). LSU Doctoral Dissertations. 3843.
McCarley, Robin L