PhD Candidate the University of Hong Kong Hong Kong, Hong Kong
Abstract: Extracellular vesicles (EVs) are critical mediators of intercellular communication and play key roles in both physiological and pathological processes. In this study, we employed the Exo-SELEX technique to screen and identify aptamers specifically targeting exosomes, thereby achieving efficient exosome isolation and detection. By immobilizing the selected aptamers on magnetic beads, we developed a novel exosome capture method. Compared with traditional approaches, this aptamer-based strategy is gentler, faster, and requires smaller sample volumes, significantly improving the efficiency and convenience of exosome isolation. To demonstrate the bioanalytical utility of this method, we analyzed the miRNA expression profiles within the captured exosomes, providing new insights into the molecular mechanisms underlying disease progression, particularly in cancer. In addition, to better investigate the molecular characteristics of the exosome surface, we introduced the DNAzyme Proximity Biotinylation technique, in which aptamers specifically bind to their targets, while DNAzyme catalytic activity generates biotin labels near the binding site, enabling precise localization of key surface molecules on exosomes. Furthermore, to expand the application of this platform, we integrated aptamers with fiber optic technology by utilizing tilted fiber Bragg gratings (TFBG) combined with a gold-coated optical fiber surface to exploit surface plasmon resonance (SPR) signals. This integration enabled the development of a highly sensitive biosensor for rapid, real-time exosome detection. In conclusion, this study utilized aptamer technology to achieve efficient exosome isolation, coupled with miRNA analysis to elucidate the biological significance of molecular cargo within exosomes, and employed DNAzyme technology for precise identification of key surface molecules on exosomes. Finally, the fiber optic sensor facilitated real-time, high-sensitivity detection of exosomes. This integrated platform not only provides an innovative tool for exosome research but also demonstrates its broad potential in disease diagnostics, biomarker discovery, and molecular mechanism exploration.
