Date of Award


Document Type


Degree Name

Master of Science (MS)



Committee Chair/Advisor

Dr. Delphine Dean

Committee Member

Dr. Renee Cottle

Committee Member

Dr. Bruce Gao


Cyanobacteria are the only known prokaryotes that can photosynthesize. Due to their unique ability, they are important entities in the global carbon and nitrogen cycles. However, two factors can turn cyanobacteria into a nuisance. In general, eutrophication is the process that supplies external nutrients that are needed for cyanobacteria blooms into bodies of water from the surrounding environment. Climate warming intensifies this process by producing carbon dioxide, methane, and nitrous oxide. With cyanobacteria blooms occurring worldwide, they are becoming a bigger threat to human health, and there has been increased interest in detecting cyanobacteria and their toxic byproducts.

For instance, cytotoxins produced - such as microcystin-LR (MC-LR) - can be detected with an immunoassay using an antibody and total internal reflection ellipsometry (TIRE), or enzyme-linked immunosorbent assay. Human health effects due to MC-LR exposure include several severe symptoms: vomiting, flu-like symptoms, abdominal pains, kidney and liver damage. Thus, there is a need to detect MC-LR before the toxin levels make cyanobacteria a health concern. To address this need, we hypothesize that we can detect MC-LR using a fully customized aptamer and a novel on-site water system biosensor.

Originally, we had focused on the cyanobacteria itself, specifically the A. flos aquae strain, as the target of detection. However, we changed our focus to MC-LR since the World Health Organization (WHO) considers the concentration of MC-LR when determining if a body of water is contaminated or not. The definition of toxic drinking water as stated by WHO is 1 microgram of MC-LR per liter of water.



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