Ultrastructure and stability of cellular nanoparticles isolated from Phaeodactylum tricornutum and Dunaliella tertiolecta conditioned media

Božič, Darja (author), Hočevar, Matej (author), Jeran, Marko (author), Kisovec, Matic (author), Bedina Zavec, Apolonija (author), Romolo, Anna (author), Škufca, David (author), Podobnik, Marjetka (author), Kogej, Ksenija (author), Iglič, Aleš (author), Touzet, Nicolas (author), Manno, Mauro (author), Pocsfalvi, Gabriella (author), Bongiovanni, Antonella (author), Kralj-Iglič, Veronika (author)

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.

• Language: English
• Keywords: nanoalgosomes, extracellular vesicles, small cellular particles, cellular nanoparticles, exosomes, electron microscopy of extracellular vesicles, characterization of extracellular vesicles, microalgae
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: ZF - Faculty of Health Sciences; FE - Faculty of Electrical Engineering; FKKT - Faculty of Chemistry and Chemical Technology; MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Publication date: 20.10.2022
• Year: 2022
• Number of pages: 14 str.
• Numbering: Vol. 2, art. 121
• PID: 20.500.12556/RUL-143702
• UDC: 577
• ISSN on article: 2732-5121
• DOI: 10.12688/openreseurope.14896.1
• COBISS.SI-ID: 136845315
• Publication date in RUL: 09.01.2023

Record is a part of a journal

• Title: Open research Europe
• Publisher: European Commission
• ISSN: 2732-5121
• COBISS.SI-ID: 80728323

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 22.10.2022

Secondary language

• Language: Undetermined
• Keywords: nanoalgosomi, zunajcelični vezikli, majhni celični delci, celični nanodelci, eksosomi, elektronska mikroskopija zunajceličnih veziklov, karakterizacija zunajceličnih veziklov, mikroalge