William S. Case
Dr. Case joined Converse in 2015 as an assistant professor. His primary teaching responsibilities include general chemistry, inorganic chemistry and biochemistry. He is an avid promoter of technology in the classroom and uses online homework and a “flipped” classroom model to promote student learning.
During his first year at Converse, Dr. Case was awarded a $127,000 DRP Target Faculty Grant from the SC IDeA Networks of Biomedical Research Excellence. In addition, he was selected as the 2017 recipient of the South Carolina Independent Colleges and Universities (SCICU) Excellence in Teaching Award. He currently serves as a Councilor for the South Carolina Academy of Science and is an active member of the American Chemical Society. In his spare time, he enjoys tennis, running, and traveling.
Scholarly & Research Activity
Dr. Case’s research interests fall within the broad areas of separation science, spectroscopy, electrochemistry and chemical education. His research at Converse explores the development of first-generation biosensors for the detection of galactose and other small molecules implicated in various molecular diseases. His work has an ultimate goal of identifying potential biosensor components that can serve as templates for targeting an array of biological analytes.
Selected Publications & Presentations
First Generation Amperometric Biosensing of Galactose with Xerogel-Carbon Nanotube Layer-by-Layer Assemblies. Labban, N., Wayu, M., Steele, C.*, Munoz, T., Pollock, J., Case, W. & Leopold, M. “First Generation Amperometric Biosensing of Galactose with Xerogel-Carbon Nanotube Layer-by-Layer Assemblies.” Nanomaterials, (2019): 9, 42 (* Converse undergraduate co-author).
Nanomaterial Adsorption Platforms for Electron Transfer Studies of Galactose Oxidase. Wayu, MB, Pannell, M.J., Case, W.S. & Leopold, M.C “Nanomaterial Adsorption Platforms for Electron Transfer Studies of Galactose Oxidase.” Bioelectrochemistry. (2019): 125, 116.
The Art of Chemistry. Case, W., Ezell, D. “The Art of Chemistry”. The Science Teacher. (December 2017).
McGown, L., & Case, W. (2011). Guanosine gels for DNA separations. In Interfaces and interphases in analytical chemistry (chapter 10). Washington, DC: ACS Publications.
Case, W., Meyers, W., & Goldman, E. (2008). Chemistry 141 Laboratory Manual. Academx Publishing.
Case, W., Glinert, K., Labarge, S., & McGown, L. (2007). Guansoine gel for sequence-dependent separation of polymorphic ssDNA. Electrophoresis, 28, 3008.
Research into biosensor development continues to gain widespread interest due to its role in several clinical and industrial applications. Enzyme-based, electrochemical biosensors have become a prevalent subdivision of the field and offer a promising method for the signaling of molecules that often serve as biomarkers in disease detection. Specifically, “1st generation” methods are becoming viable strategies for the amperometric sensing of biomolecules. In this scheme, an analyte reacts with a specific oxidase enzyme to generate hydrogen peroxide (H2O2), and the peroxide is subsequently oxidized at a working electrode. The generated signal is therefore an indirect measure of the amount of analyte present.
The work proposed herein will study the development of a 1st generation biosensor for the detection of galactose, with potential applications in the diagnosis of galactosemia. This disease is a genetic disorder associated with a comprised ability to metabolize the galactose sugar and can be fatal if not detected early. The proposed work will present a novel diagnostic method since the sugar itself will be targeted, thus differing from current clinical methods that target the enzymes involved in the sugar’s metabolism. Research planned for the granting period will investigate optimum conditions for enzyme immobilization and signal selectivity.
First generation biosensing hinges upon incorporating an enzyme into a scaffold that will protect its native structure and function. Xerogels created from silane precursors will be examined in this work as potential matrices for enzyme immobilization and subsequent catalysis. Xerogels offer many attractive features including chemical inertness, rigidity, and negligible swelling in aqueous solution. Platinum electrodes modified with galactose oxidase (GAOx) embedded xerogels will be examined for their ability to detect galactose through a 1st generation sensing mechanism. Their viability as potential scaffolds will be determined by examining key sensing parameters, including response time to galactose, the linear dynamic range for varying galactose concentrations, and the inherent sensitivity of the sensor to the sugar molecule. The use of silane precursors with different “R” groups will allow us to examine how xerogel structural features (film porosity and hydrophobicity) may affect biosensor performance. In addition, the conditions under which xerogel films are dried/aged will be examined to determine if a set of optimum experimental parameters exist for film formation.
Results from the above studies will guide experimentation into the use of multiple xerogel layers in sensor design. Previous work in biosensing has shown that a layer-by-layer (L-B-L) approach can result in amperometric signal enhancement. Sensors consisting of both an enzyme doped xerogel layer and a non-enzyme layer will be explored for their effect on the aforementioned sensing parameters. The use of mixed xerogel layers is also envisioned as part of this work.
The ability of the proposed sensor to selectively target galactose will also be investigated through the incorporation of outer membranes into biosensor design. Polyphenol (PP) and polyurethane (PU) blended layers will be examined as potential outer layers capable of allowing the selective passage of galactose and O2 while preventing the passage of interferent molecules common in clinical or endogenous settings.