20.500.12556/RUL-143702 Ultrastructure and stability of cellular nanoparticles isolated from Phaeodactylum tricornutum and Dunaliella tertiolecta conditioned media Background: Cells in general secrete nanoparticles (NPs) which are believed to mediate intercellular communication. Recently, great efforts have been made to utilize them as delivery vectors. We aimed to harvest and identify NPs from liquid cultures of two marine microalgae Dunaliella tertiolecta and Phaeodactyum tricornutum. Methods: NPs were isolated from the culture conditioned media by differential ultracentrifugation by the protocol used for the isolation of extracellular vesicles. Microalgae and isolated NPs were examined by scanning electron microscopy (SEM) while isolated NPs were examined also by cryogenic transmission electron microscopy (cryo-TEM). The Triton X-100 detergent and temperature sensitivity of NPs was assessed by dynamic light scattering (DLS) through monitoring the intensity of the scattered light (I) and the distribution of hydrodynamic radii of NPs (Rh). Results: Two mechanisms of formation of NPs with average Rh 200 nm were observed in the D. tertiolecta culture: a disintegration of tubular protrusions, and cell decay. A part of the imaged D. tertiolecta NPs were membrane-enclosed vesicles, but the isolates also contained electron-dense NPs and nanofilaments. P. tricornutum NPs in the culture and in the isolate were homogeneous in size and shape. Their average Rh was 104 nm. The addition of surfactant to isolates resulted in a change in Rh distribution and a decrease of I in samples from both species, indicating decay of a part of NPs. Changes in the width of the I(Rh) peaks were observed at temperatures above 45 °C. Conclusions: A part of NPs found in isolates from microalgae D. tertiolecta and P. tricornutum were membrane-enclosed vesicles. However, the isolates obtained by a standard protocol for extracellular vesicle isolation by ultracentrifugation contained also a significant amount of other similar-sized nanoparticles. The isolates were partly susceptible to the addition of detergent and to temperature up to 80 degrees. nanoalgosomes extracellular vesicles small cellular particles cellular nanoparticles exosomes electron microscopy of extracellular vesicles characterization of extracellular vesicles microalgae nanoalgosomi zunajcelični vezikli majhni celični delci celični nanodelci eksosomi elektronska mikroskopija zunajceličnih veziklov karakterizacija zunajceličnih veziklov mikroalge true false true Angleški jezik Ni določen Članek v reviji 2023-01-09 14:05:46 2023-01-09 14:05:48 2023-01-10 03:29:58 0000-00-00 00:00:00 2022 0 0 14 str. art. 121 Vol. 2 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2022-10-20 577 2732-5121 10.12688/openreseurope.14896.1 136845315 eb398973-3397-4460-ae4c-cddf50ae51cd_14896_-_veronika_kralj-iglic_(1)_(1).pdf eb398973-3397-4460-ae4c-cddf50ae51cd_14896_-_veronika_kralj-iglic_(1)_(1).pdf 1 5D9E7EF6F805F1A48566291AE61062A5 a6de9254d279bb889c72ac0dc89008e3fec2f538fd3c2cbcb73521c54cc5ab05 0b494fc5-901f-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=165574 https://open-research-europe.ec.europa.eu/articles/2-121 1 1ccfe731-901e-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=165573 Zdravstvena fakulteta Fakulteta za elektrotehniko Fakulteta za kemijo in kemijsko tehnologijo Medicinska fakulteta 0 0 0