DOI
https://doi.org/10.25772/KZHR-WV26
Author ORCID Identifier
0000-0002-1994-4939
Defense Date
2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Joseph Turner
Second Advisor
Xuewei Wang
Third Advisor
Vladimir Sidorov
Fourth Advisor
Julio Alvarez
Fifth Advisor
Hong Zhao
Abstract
The current healthcare system often relies on occasional checkups, which can result in diseases being undetected until severe symptoms are present, leading to a reactive approach to healthcare. Optochemical sensors and nanoparticles (NPs) have the potential to address this deficiency by enabling real-time and continuous analysis of various biomarkers, allowing for proactive healthcare based on evidence at a molecular level. This study focused on enhancing and functionalizing current implantables or wearables through three different optochemical sensors and devices: ion-selective optodes (ISO), chemical sensors, and fluorescent NPs. We developed cost-effective and mass-reproducible ISOs by modifying sports fabrics with sensing chemicals, such as a pH indicator, an ion exchanger, and an ionophore, via inkjet printing. The ISOs retained the essential properties of fabrics, including flexibility, stretchability, wickability, and breathability, while allowing continuous monitoring of various biomarkers in sweat (Na+, K+, pH). Moreover, we created an indwelling catheter-based chemical sensor by functionalizing a foley catheter for on-body detection of Escherichia coli (E. coli) in biofluids such as urine. The nitrosation of indole initiates the reaction, generating a red dimeric product, indoxyl red, with high absorbance at 537 nm. Our method can detect indole and E. coli in real foley catheters, providing a promising avenue for real-time and continuous monitoring of biomarkers. Additionally, we enhanced the fluorescence of organic fluorescent NPs used for bioimaging by making them biocompatible and reducing quenching caused by the aggregation of dye molecules. We developed a novel method to prevent aggregation-caused quenching (ACQ) of cationic dyes using mercuracarborands (MCs). The MCs spontaneously self-assemble and form a complex with various anion counterparts of the cationic dye within the NP, increasing the spatial distance between neighboring dye molecules and reducing excitonic coupling and ACQ. Lastly, the study addresses a long-standing issue in fluorescence analysis known as the inner filter effect (IFE). The impact of IFE was mitigated in the analysis of high concentrations of quinine sulfate by employing multiple fluorescence spectrometers with different slit configurations (horizontal and vertical) and applying mathematical corrections. This approach enables researchers to obtain precise fluorescence measurements and achieve more accurate analysis, which is crucial for the reliable interpretation of fluorescence measurements. This study demonstrates the significant promise of optochemical sensors and NPs for real-time and continuous monitoring of various biomarkers and a more precise bioimaging technique.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-10-2023
Included in
Analytical Chemistry Commons, Biological Factors Commons, Investigative Techniques Commons, Other Chemicals and Drugs Commons, Physical Chemistry Commons, Polymer Chemistry Commons