122nd General Meeting of the KCS

Type Symposium
Area Exosome: from Concept to Clinic
Room No. Room 314
Time FRI 15:40-:
Code LIFE3-4
Subject Isolation and Analysis of Extracellular Vesicles
Authors Jaesung Park
Mechanical Engineering/ I-Bio, Pohang University of Science and Technology, Korea
Abstract In research about extracellular vesicles, two limitations hinder advances, isolation and analysis of extracellular vesicles. For better isolation, we adapted the aqueous two-phase system (ATPS) to diagnose prostate cancer by isolating EVs from patients’ urine. ATPS was optimized by adjusting polymer concentration. EVs were isolated in the first phase with efficiency of ~100%; total processing time is just ~ 30 min. After the ATPS isolated EVs from patients’ urine, PCR and ELISA kit were used to detect EVs derived from prostate cancer cells. The expression levels of mRNA and protein markers of prostate cancer were measured, and the relationship between expression levels and clinical data was analyzed. As a result, diagnostic ability based on ATPS is better than conventional ones (serum PSA and sediments); sensitivity is increased at least 10%, and specificity is improved at least 20% compared to conventional methods
Along with isolation, analysis of extracellular vesicle is challenging as well. For analysis of heterogeneity of extracellular vesicles, the multi-color particle tracking analysis system for quantified characterization of individual extracellular vesicles is developed, which simultaneously analyzes trajectories of multiple suspended particles visualized by scattered light and fluorescence of three colors. The fluorescence particle test shows that the algorithm showed 0.22% false positives and 8.3% false negatives for the fluorescence signal. This system is capable of tracking the signal of SYTO nucleic acid dye stained inside EV and fluorescence protein expressed in EV as well as bright dye. Using various combinations of fluorescence staining, it is possible to distinguish subpopulation of particles bearing each marker in the human plasma. Through the subpopulation, it is estimated the number of total particle, particles bearing genes, lipoproteins and particles bearing extracellular vesicle (EV) related markers. Also, the colocalization of fluorescent probes is analyzed to determine the tendency of which markers are likely to coexist in the same particle. By combing those methods mentioned above , we could analyze subpopulation of extracellular vesicles, and could be useful in diagnosis, extracellular vesicle quality control in therapeutic applications.
E-mail jpark@postech.ac.kr