Date of Award

8-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Bioengineering

Committee Member

Delphine Dean, Committee Chair

Committee Member

Zhi Gao

Committee Member

Naren Vyavahare

Abstract

Waterborne diseases account for millions of deaths each year. Developing countries struggle with infectious outbreaks occurring due to the presence of microbial agents in the water supply, and the morbidity rate remains high due to lack of detection. Even in the United States with modern water treatment facilities, lost productivity due to waterborne pathogens costs an estimated $20 million per year. There are many contaminants that are difficult and costly to detect even in developed countries, such as cyanobacteria. Cyanobacteria has particularly been a problem in upstate South Carolina, and the presence of this contaminant affects the quality of water and can make people ill at high levels. Thus, there is a need for simple and affordable tests to detect a wide variety of microorganisms.

Our novel biosensor utilizes plant-based, sugar-binding lectin arrays to bind microorganisms on electrode surfaces. Our group has found during testing that pathogens bind strongly and selectively to certain lectin-coated electrodes, which impedes the flow of electricity between two electrodes, increasing resistance. Quantification of this change in resistance can be used to determine the presence of different types of bacteria. Several different design iterations of this lectin-based biosensor were evaluated with three different types of bacteria: Escherichia coli, Staphylococcus aureus, and Anabaena flos-aquae, a type of filamentous cyanobacteria. Different lectins, including concanavalin A, peanut agglutinin, and wheat germ agglutinin, were evaluated for cyanobacteria binding. It was found that resistance-based measurements were not adequately stable for field testing; thus, a sensor based on refractive index with lectin coated optical fibers was tested with more promising results for the detection cyanobacteria.

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