resistive-pulse sensing, Coulter-counter, nanopipette, fluorescence, liposomes, cryoTEM Extracellular vesicles (EVs) are small, cell-derived unilamellar liposomes that contain biomolecules both in the interior of the liposome (e.g., DNA, RNA, proteins), in addition to membrane bound proteins on their exterior. Recent studies suggest that the contents of EVs are directly correlated with their physical size. Zhang et al. proposed a correlation between the size of EVs derived from AsPC-1 human pancreatic cancer and MDA-MB-231-4175 human breast cancer cell lines and their contents consisting of proteins, lipids, DNA, and RNA. They reported diverse organ bio-distribution patterns for cancer-derived EVs of different sizes in mouse models and proposed biological functions of the EVs based on vesicle content and location within the body. This work required the use of several analytical techniques, including field flow fractioning, light scattering, transmission electron microscopy, and nucleic acid analysis, to separate and characterize the EV subpopulations. Characterizing the contents of cancer-derived EVs on a vesicle-by-vesicle basis to identify subpopulations is critical to understanding disease progression and treatment, hence, there is a need for a method capable of extreme sizing precision with the ability to probe uniquely targetable characteristics, such as fluorescently labeling specific surface proteins. Herein, we report simultaneous multipass resistive-pulse sensing and fluorescence imaging to characterize biologically relevant model liposomes based on their size and the presence of fluorescent markers.