Bioengineering Graduate Program - PhD Thesis Presentation - Development of Aggregation-Induced Emission-Based Bioprobes for Specific Organelle Imaging and Tracking

Fluorescence microscopy is a powerful tool to study many biological processes due its high temporal and spatial resolutions, high sensitivity, and compatibility with live cells, tissues, and animals with the aid of fluorescent materials. Although fluorescent proteins have been the popular choice of fluorescent materials to study biological systems, they are still lacking compared with the best organic fluorophores in terms of “photon budgets”. Therefore, in recent years, numerous techniques were developed to provide conventional organic fluorophore genetic specificity, emphasizing the importance of developing and exploring a new class of organic fluorophores. In 2001, a phenomenon where an opposite phenomenon to aggregation-caused quenching (ACQ) was proposed as aggregation-induced emission (AIE). Luminogens with AIE characteristics offer features such as easy generation of turn-on bioprobes and allowing their use in high concentrations without suffering from ACQ. In the last two decades, various new AIE luminogens were developed and applied to various applications in optoelectronics, biological and chemical sensors, bioimaging, and image-guided therapy. This thesis reports the synthesis and characterization of novel AIE luminogens with high photostability, good biocompatibility, and easy synthesis over their predecessors. Using a range of microscope imaging techniques, their applicability in various biological systems such as different cell states of HeLa cell cultures, diagnosis of liver disease, and targeting and tracking of mitochondria in neurons was demonstrated. Taken together, my thesis work adds to the toolbox of organic fluorophores for biological studies.