Fig. 5.

Excipients suitable for the formulation of MSC-secretome and EVs. Buffers stabilize the pH to appropriate values compatible with the body administration and the product stability (e.g., to minimize hydrolysis and oxidation of proteins and lipids). Salts increase the ionic concentration making the preparation isosmotic with the body fluids. Sugars and polyols have many OH groups that surround and stabilize (by H-bonds) proteins and EVs even when the water in the formulation is subtracted following freezing or freeze-drying. Finally, proteins are adsorbed on the surface of EVs, creating a protein corona that prevents EV fusion and stabilizes the lipidic layer when the water in the formulation is subtracted following freezing or freeze-drying. Created with BioRender.com.