Author ORCID Identifier
https://orcid.org/0000-0001-8987-2494
Defense Date
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Julio Alvarez
Abstract
Antibiotic-resistant bacteria pose a significant and escalating threat to hospitals around the world, necessitating the development of rapid and sensitive detection methods. Single-entity electrochemistry has emerged as a promising approach for detecting and identifying such bacteria, and monitoring the efficacy of antibiotics in real-time. Herein, we employ the translational diffusion equation for circular cylinders to predict the collision frequency of rod-shaped bacteria, informing our experimental setup. Our work demonstrates that lab-fabricated Pt ultramicroelectrodes can sensitively detect bacteria at femtomolar concentrations under migration-controlled conditions. Further, we present a method implemented in MatLab to automate the analysis of step-like signals observed in chronoamperograms. By applying a first-derivative Savitzky-Golay filter to the signals, we transform them to spike-like signals, facilitating quantification. Integration of the area under each peak allows us to quickly determine the magnitude of current change and duration corresponding to the bacteria adsorbing to the electrode surface. With this powerful tool, we demonstrate the potential to distinguish two discrete bacteria species, Aeromicrobium erythreum and Bacillus subtilis, within mixed samples by generating bi-dimensional plots of the step magnitudes. Finally, we test the capability of our system to monitor the response of B. subtilis following exposure to the antibiotic valinomycin. Interestingly, the observed signal changes post-exposure, which is attributed to interactions between non-viable bacteria and the electrode surface. These findings underscore the potential of single-entity electrochemistry for rapid bacterial detection and identification, and antibiotic efficacy assessment, offering valuable insights into combatting antibiotic resistance in clinical settings.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-10-2024