PhD Dissertation Defense: Zach Sheffield

Carbon dots are an emerging type of carbon nanomaterial lauded for their 3- 10 nm sizes, photoluminescent properties, simple synthesis from cost-effective materials, good water solubility, polar surface functionalities, and good biocompatibility. Consequently, they have found considerable use in the biomedical sciences as imaging agents, carriers for drug delivery, substrates for biofunctionalization, and transduction elements in biosensors. However, a growing body of literatures investigating the PL origins of the most applied subtypes of CDs, those synthesized from bottom-up reactions, have raised questions about what the byproducts of these reactions are and how are they impacting the observed properties. Such CDs are notorious for their compositional complexity which is often used to explain their poor reproducibility. With this information in mind, we developed a biosensor for the detection of extracted SARS-CoV-2 RNA that relied on the forced aggregation induced emission enhancement (AIEE) of CDs, conjugated with antisense oligonucleotides, (ASOs) when they bound with the viral RNA. We found that changing the dialysis conditions of the CD-ASO conjugate or removal of large particles before introducing them to the SARS-CoV-2 RNA significantly impacted sensor performance. Following this study, we attempted to develop a CD based biosensor for the detection of stress biochemical markers using some of the CDs used in the SARS-CoV-2 biosensor, we found that after extensive purification, the CDs would assemble into ordered polymeric structures whose morphologies depended on the solvent used.

Ph.D. Defense  Committee:  Zach Sheffield

Monday, April 21 · 12:30 – 1:30pm

Time zone: America/New_York

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