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Gupta, Rupsa

University of British Columbia

Semiconducting polymer nanoparticles (Pdots) are rapidly gaining popularity as bright fluorescent material owing to their superior per-particle brightness, large absorption cross-sections, biocompatibility, and ease of synthesis. However, Pdots suffer from several limitations and are yet to realize their full potential as a tool for bioanalysis and imaging. Typical nanoprecipitation methods of preparing Pdots suffer from poor control and reproducibility. Limited surface bioconjugation chemistries have been reported with Pdots. As they are only held together by relative weak entropic forces, Pdots are only moderately stable, often suffering from long-term stability issues and non-specific binding on the surface. Additionally, photophysics of Pdots are poorly understood which preclude rational design of bioanalytical probes with them and rely heavily on the ‘trial and error’ approach. Being relatively new materials, much optimization is warranted to enable their widespread use in bioanalysis, bioimaging and prospective point-of-care (POC) applications. This thesis presents a brightness study of Pdots in comparison to inorganic semiconductor nanoparticles or quantum dots (QDs) using smartphone imaging to validate their use in prospective POC applications. Limitations with Pdot stability affected performance in a model assay and motivated the development of stabler Pdots. Two approaches of stabilizing them have been presented in the thesis: silica encapsulation and albumin stabilization. These approaches are compared to the conventional Pdots, in the context of physical, colloidal, optical stability and surface chemistry. Lastly, a comprehensive study of their photobleaching photophysics has been presented to enable rational design of photostable Pdots benefitting long-term imaging and tracking applications.

Text

2024-03-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/82616

Chemistry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/