Preservation and Storage Stability of Extracellular Vesicles for Therapeutic Applications

Abstract

Recently, extracellular vesicles (EVs)-including exosomes, microvesicles, and others-have attracted interest as cell-derived biotherapeutics and drug delivery vehicles for a variety of applications. This interest stems from favorable properties of EVs, including their status as mediators of cell-cell communication via transfer of biological cargo and their reported ability to cross biological barriers that impede many delivery systems. However, there are many challenges to translation and widespread application of EV-based therapeutics. One such challenge that has yet to be extensively studied involves EV preservation and storage, which must be addressed to enable use of therapeutic EVs beyond resource-intensive settings. Studies to date suggest that the most promising mode of storage is - 80°C; however, understanding of storage-mediated effects is still limited. Additionally, the effects of storage appear to vary with sample source. The lack of knowledge about and standardization of EV storage may ultimately hinder widespread clinical translation. This mini-review reports current knowledge in the field of EV preservation and storage stability and highlights future directions in the area that could be critical to eventual development of EV therapies.

Adipose‐Derived Biogenic Nanoparticles for Suppression of Inflammation

“…Indeed, studies have shown that EVs retain function after lyophilization 81,82. Although less clinically feasible, Lipo‐NPs could alternatively be stored at −80 °C (for up to two years), as studies have shown that both EVs and lipoproteins remain stable under such conditions 83,84…”

Mesenchymal Stem Cell-Derived Exosomes and Other Extracellular Vesicles as New Remedies in the Therapy of Inflammatory Diseases

“…Additionally, clinical applications of MSC-EVs require their long-term use and considerable thought must be given to the preservation of their immunosuppressive potential [21]. A large number of studies demonstrated that the most convenient mode of storage for MSC-EVs remains −80 • C [109]. Nevertheless, due to the complex cold chain logistics, alternatives such as lyophilization and the incorporation of additives might be necessary to improve MSC-EV storage stability during transportation [21,109].…”

Scalable Production and Isolation of Extracellular Vesicles: Available Sources and Lessons from Current Industrial Bioprocesses

“…Freeze/thaw cycles should be minimized, although it has been reported that EVs are relatively stable after several cycles . In this context, cryoprotectants such as trehalose, already used for labile proteins, vaccines, and liposomes, appear to have a positive impact on EVs . Additionally, Frank et al reported that freeze‐drying does not significantly impact the size and particle number of MSC‐derived EVs and that, upon addition of cryoprotecting sugars, the enzymes in the lyophilized EVs have comparable activity to the ones in EVs stored at −80 °C.…”