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Alian, Sara

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Alian

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Sara

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Alian, Sara
Author's Publications: search.filters.isAuthorOfPublication.3be9addb-bf7a-43ab-a219-5e5267e0437e

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    Alternative Methods for Characterization of Extracellular Vesicles
    (Frontiers Research Foundation, 2012) Balaj, Leonora; Tigges, John; Toxavidis, Vasilis; Ivanov, Alexander R.; Skog, Johan; Momen-Heravi, Fatemeh; Alian, Sara; Ericsson, Maria; Distel, Robert; Kuo, Winston
    Extracellular vesicles (ECVs) are nano-sized vesicles released by all cells in vitro as well as in vivo. Their role has been implicated mainly in cell–cell communication, but also in disease biomarkers and more recently in gene delivery. They represent a snapshot of the cell status at the moment of release and carry bioreactive macromolecules such as nucleic acids, proteins, and lipids. A major limitation in this emerging new field is the availability/awareness of techniques to isolate and properly characterize ECVs. The lack of gold standards makes comparing different studies very difficult and may potentially hinder some ECVs-specific evidence. Characterization of ECVs has also recently seen many advances with the use of Nanoparticle Tracking Analysis, flow cytometry, cryo-electron microscopy instruments, and proteomic technologies. In this review, we discuss the latest developments in translational technologies involving characterization methods including the facts in their support and the challenges they face.
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    Impact of Biofluid Viscosity on Size and Sedimentation Efficiency of the Isolated Microvesicles
    (Frontiers Research Foundation, 2012) Momen-Heravi, Fatemeh; Balaj, Leonora; Alian, Sara; Trachtenberg, Alexander J.; Hochberg, Fred H; Skog, Johan; Kuo, Winston
    Microvesicles are nano-sized lipid vesicles released by all cells in vivo and in vitro. They are released physiologically under normal conditions but their rate of release is higher under pathological conditions such as tumors. Once released they end up in the systemic circulation and have been found and characterized in all biofluids such as plasma, serum, cerebrospinal fluid, breast milk, ascites, and urine. Microvesicles represent the status of the donor cell they are released from and they are currently under intense investigation as a potential source for disease biomarkers. Currently, the “gold standard” for isolating microvesicles is ultracentrifugation, although alternative techniques such as affinity purification have been explored. Viscosity is the resistance of a fluid to a deforming force by either shear or tensile stress. The different chemical and molecular compositions of biofluids have an effect on its viscosity and this could affect movements of the particles inside the fluid. In this manuscript we addressed the issue of whether viscosity has an effect on sedimentation efficiency of microvesicles using ultracentrifugation. We used different biofluids and spiked them with polystyrene beads and assessed their recovery using the Nanoparticle Tracking Analysis. We demonstrate that MVs recovery inversely correlates with viscosity and as a result, sample dilutions should be considered prior to ultracentrifugation when processing any biofluids.