Date of Award

6-10-2026

Document Type

Thesis

Publisher

Santa Clara : Santa Clara University, 2026

Departments

Bioengineering

First Advisor

Zhiwen Zhang

Abstract

One of the largest causes of food waste in the United States is recall or disposal of produce due to bacterial infection, with a prevalent cause being the pathogen Salmonella enterica Serovar Typhimurium. Current detection methods are inadequate for many use cases due to cost and speed of detection. In this paper, we propose and demonstrate a novel method of detecting the presence of S. Typhimurium quickly using a combination of aptamers and love-surface acoustic wave sensors. Our experiments demonstrate repeatable changes in sensor response during exposure to S. Typhimurium under test conditions. Our data shows a measurable difference in signal magnitude between our positive test solution, our negative control, and our method blank solution. While a positive correlation can be drawn from the data collected, errors arise in extended or repeated use. We attribute these issues to a combination of leakage issues, salt corrosion from the chemical properties of biological test conditions, and changes in electrical detection factors based on uncontrolled factors like viscosity and unwanted material deposition or corrosion. To prove the industrial efficacy of this detection method, further testing and refinement are necessary. The aptamer specificity must be tested with a different but physically similar strain of Salmonella, and true limits of detection must be probed through the development of a titration curve and accompanying mathematical relation. We hope that future work will prove the impact this can have on agriculture.

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