Getnet Midekessa
Research Fellow, Faculty of Biomedicine, University of Tartu, Estonia
Getnet Midekessa received his BSc in Applied Chemistry from Hawassa University, Ethiopia. Following graduation, he worked in the food complex and pharmaceutical industry located in Ethiopia. Later he completed his master's studies in protein science and Biotechnology from the University of Oulu, Finland. During his master studies and post-graduation, he worked on projects involving protein characterization and Extracellular vesicles research at the Faculty of Biochemistry and Molecular Medicine at the University of Oulu.
Getnet started his doctoral study in March 2018 in the Institute of Biomedicine and Translational Medicine, University of Tartu under the supervision of Prof. Fazeli. He is also working as a specialist at the Estonian University of Life sciences in the Institute of Veterinary Medicine and Animal Sciences. His research interests are focusing on the detection of surface extracellular vesicles using different biosensing technologies, as well as developing a novel diagnostic biomarker for different diseases.
Getnet started his doctoral study in March 2018 in the Institute of Biomedicine and Translational Medicine, University of Tartu under the supervision of Prof. Fazeli. He is also working as a specialist at the Estonian University of Life sciences in the Institute of Veterinary Medicine and Animal Sciences. His research interests are focusing on the detection of surface extracellular vesicles using different biosensing technologies, as well as developing a novel diagnostic biomarker for different diseases.
Evaluation of lipophilic dye labelling of extracellular vesicles using
fluorescent nanoparticle tracking analysis
Different fluorescent molecules have been used to label EV membranes. A well-established fluorescent method involves maintaining the size of EVs after labelling. CellMask™ Green (CMG) dyes, which are lipophilic fluorescent dyes, are widely used to label plasma membranes of EVs. Using fluorescent NTA (fl-NTA), we investigated conditions that affect the optimal CMG labelling of EVs derived from human choriocarcinoma JAr cells and different biological fluids. The effect of CMG labelling on the size, concentration, and zeta potential (ZP) of JAr EVs purified using different methods, incubation temperatures, and detergent treatments was assessed. According to Fl-NTA analysis, the mean size of fluorescent nanoparticles (fl-NPs) decreased significantly with increasing concentrations of CMG dye (p ≤ 0.05 ). Furthermore, fl-NPs derived from JAr cells with the lowest and highest dye concentrations showed a significant shift towards more and less negative ZP values, respectively (p ≤ 0.05 ). A difference in the concentration of fl-NPs was observed between JAr EVs purified via size-exclusion chromatography (SEC) alone and those purified using SEC combined with tangential flow filtration. The proportion of fl-NPs in bovine follicular fluid and seminal-plasma derived EVs was higher and lower than that in cell-culture derived EVs, respectively. These findings suggest that CMG labelling may be useful for the detection and characterization of EVs using fl-NTA.