College - Author 1

College of Engineering

Department - Author 1

Materials Engineering Department

Degree Name - Author 1

BS in Materials Engineering

College - Author 2

College of Engineering

Department - Author 2

Materials Engineering Department

Degree - Author 2

BS in Materials Engineering



Primary Advisor

Jean Lee, College of Engineering, Materials Engineering Department


Water sanitation is a serious issue affecting the lives of many, and methods for assessing water cleanliness have been a major research interest for decades. Rapid and accurate water pathogen detection methods that can be performed in field applications have been a growing research focus, especially in low-income countries most affected by poor water quality. Silicon nitride was explored as a material for colorimetric water-pathogen sensing due to the large body of knowledge around its processing, and its isoelectric point. A bioassay of chlorophenol red-β-Dgalactopyranoside (CPRG) and β-galactosidase (β-gal) enzymes with Escherichia coli (E. coli) bacteria was used to examine the colorimetric reading produced by electrostatic binding of E. coli to the surface of etched silicon nitride samples. Silicon nitride samples were produced by etching a pattern of repeating 250 μm side-length squares onto a silicon nitride wafer for different etch durations using buffered oxide etch (BOE) to increase its surface area for E. coli binding. Roughness and surface area were measured via profilometry and Brunauer-EmmettTeller (BET) analysis, respectively. After being submersed in the bioassay, the colorimetric readout was measured via spectrophotometry. Some statistically significant differences were observed for larger samples at longer etch-times compared with control values, though this trend was inconsistent. Further research should be conducted to investigate methods for producing samples with sufficient surface area for adequate and consistent bacteria binding.