Date Thesis Awarded
5-2024
Access Type
Honors Thesis -- Access Restricted On-Campus Only
Degree Name
Bachelors of Science (BS)
Department
Chemistry
Advisor
Elizabeth J. Harbron
Committee Members
Kristin L. Wustholz
John C. Poutsma
Sarah E. McCartney
Abstract
Conjugated polymer nanoparticles (CPNs) have powerful applications in fluorescence imaging due to their brightness, photostability, and compatibility with aqueous media. CPNs have recently received attention for their ability to generate reactive oxygen species (ROS), making them potential candidates for new photocatalytic and photodynamic therapy applications. Although reports of CPN ROS generation largely focus on singlet oxygen production, CPN excited states can also generate superoxide radical anion through an alternate CPN excited state deactivation pathway. Here, we demonstrate that CPNs generate superoxide upon irradiation by doping the CPNs with a hydrocyanine dye that becomes fluorescent upon reaction with superoxide. Superoxide production induces an off to on fluorescence response in the dye-doped CPNs by converting quenching hydrocyanine dyes into fluorescent cyanine dyes. The cyanine dyes act as fluorescence resonance energy transfer (FRET) acceptors for the multi-chromophoric CPNs resulting in amplified cyanine fluorescence signals. Variation of the irradiation intensity, dye loading level, and CPN composition allows for the manipulation and optimization of the dye-doped CPNs’ fluorescence response to irradiation. Motivated by the FRET amplification of the cyanine signal, ongoing and future work focuses on decoupling superoxide production and detection with possible applications in the design of a dye-doped CPN superoxide probe.
Recommended Citation
Clayborn, Anna, "Self-Reporting Conjugated Polymer Nanoparticles for Superoxide Generation and Detection" (2024). Undergraduate Honors Theses. William & Mary. Paper 2190.
https://scholarworks.wm.edu/honorstheses/2190
