R from technical troubles, and classical nanoparticle tracking evaluation (NTA) permits quantification and size determination of particles, but fails to discriminate amongst EVs, lipids and protein aggregates. Fluorescence-based NTA (FL-NTA) is definitely an emerging approach for counting and phenotyping of EVs. EVs is usually fluorescently labelled with non-specific membrane markers or with antibodies particularly recognizing EV surface marker proteins. We’re currently establishing a differential FL-NTA system utilizing certain antibodies against surface markers in analogy to cell flow cytometric analysis. Procedures: EVs from umbilical cord mesenchymal stromal cells (UCMSCs) had been isolated by a tangential flow filtration/ultracentrifugation protocol with or devoid of subsequent size exclusion chromatography. EV preparations had been stained with AlexaFluor 488-conjugated distinct antibodies or corresponding isotype controls. Quantity and size of particles in typical scattering light mode (N mode) versus fluorescence mode (FL mode, laser wavelength 488 nm) was measured applying ZetaView Nanoparticle Tracking Analyzer (Particle Metrix). Outcomes: All UC-MSC-EV preparations had been identified constructive for standard EV marker proteins and unfavorable for MHC I. Extra purification of EV preparations by size exclusion chromatography led to a higher percentage of EV marker protein-positive nanoparticles. Summary/Conclusion: Differential FL-NTA facilitates determination of your percentage of EV marker protein-positive nanoparticles inside a mixed particulate resolution. We aim to expand our set of markers to other MSC-EV positive and negative surface marker proteins so that you can establish FL-NTA-based surface marker profiling as an further approach for quantifying EVs. Funding: This function was supported by project EXOTHERA (funded by the European Regional Development Fund and Interreg V-A ItaliaNIMA Related Kinase 3 Proteins site Austria 2014-2020).PS09.Imaging flow cytometry: a potent strategy to identify distinct subpopulations of tiny extracellular vesicles Michel Bremer1; Rita Ferrer-Tur1; AndrG gens2; Verena B ger3; Peter A. Horn3; Bernd Giebel3 Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; 2Clinical Analysis Center, Division for Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden, H sov en, Sweden; 3Institute for Transfusion Medicine, University Hospital Essen, Essen, GermanyPS09.Differential fluorescence nanoparticle tracking analysis for enumeration in the extracellular vesicle content material in mixed particulate solutions Karin Pachler1; Alexandre Desgeorges1; Christina Folie1; Magdalena Mayr1; Heide-Marie Binder1; Eva Rohde2; Mario Gimona1 GMP Unit, Spinal Cord Injury and DNA Topoisomerase I Proteins Storage & Stability Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Healthcare University Salzburg, Salzburg, Austria; 2 GMP Unit, Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS) and University Institute for Transfusion Medicine, Paracelsus Health-related University Salzburg, Salzburg, AustriaBackground: Though distinctive extracellular vesicle forms happen to be defined concerning their cellular origin, for now, exosomes can hardly been discriminated from smaller microvesicles or other modest EV varieties. You will discover hardly any solutions offered, now, permitting to discriminate various EV-types of comparable sizes. Recently, we’ve got optimized imaging flow cytometry for the single EV detection and characterization of compact EVs (7050 nm) . Upon extending our imaging flow cytometric ana.