The utilization of boron-rich clusters as aids to detect reactive oxygen and nitrogen species through non-fluorescent modalities
Date
2025
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Publisher
University of Delaware
Abstract
Reactive oxygen and nitrogen species (ROS/RNS) are small, highly reactive, and transient oxygen/nitrogen containing compounds that play important roles in redox signaling processes to maintain cellular homeostasis. Typically, these finnicky species are detected through activity-based sensors (ABS) which produce a fluorescent response after being selectively uncaged by the target analyte. However, these fluorescent scaffolds are limited by their large absorption and emission profiles. Therefore, to expand our ability to detect these species, our lab aims to develop and characterize this new class of activity-based sensors to detect these species via non-fluorescent imaging modalities utilizing boron-rich clusters. These boron-rich clusters have unique, tunable properties that are advantageous for alternative based imaging strategies such as time-of-flight mass spectrometry (ToF-SIMS) or Raman spectroscopy. Utilizing these non-fluorescent scaffolds, we hope to expand the toolbox ROS/RNS targeting scaffolds to further understand their behavior within biological systems. ☐ In Chapter 1, I will discuss progress made towards the synthesis and photophysical characterization of this novel class of ABS scaffolds. A strategy to attach a boron-rich cluster to a known fluorescent scaffold was developed. These new dye derivatives were then characterized through UV-Vis and fluorescence spectroscopy to observe how the addition of the cluster impacted the dye’s photophysical properties. Additionally, multiple formylations of these unique dyes were attempted and screened for optimal conditions. An alternative synthetic route is proposed to bypass obstacles and limitations within the current pathway. ☐ In Chapter 2, I will discuss preliminary studies which demonstrate the viability of these boron-rich cluster compounds for alternative imaging strategies in biological systems. A protocol to reliably prepare cells for ToF-SIMS analysis was developed. Using this method, a cell sample was imaged via ToF-SIMS for the first time at the University of Delaware. Building off these preliminary experiments, cells were incubated with a dye conjugated to a boron-rich cluster then analyzed via fluorescence microscopy and ToF-SIMS. Shortcomings of the current strategy are discussed alongside potential solutions to troubleshoot complications encountered in follow-up experiments.
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Keywords
Reactive oxygen and nitrogen species, Activity-based sensors, Boron-rich clusters, Fluorescence microscopy, ToF-SIMS