Assessment of bovine milk exosome preparation and lyophilized powder stability

Exosomes are cell-derived nanovesicles that play a crucial role in intercellular communication, presenting promising potential as biomarkers and therapeutic agents. Bovine milk exosomes (MK-Exo) show production scalability and cost-effectiveness, offering distinct advantages over cell-derived exosomes. However, exosome storage and transportation are challenging owing to their unstable nature, necessitating preservation at ultralow temperatures. Research findings suggest that freeze-drying could provide a viable solution; however, different sources of exosomes may require specific protocols. In this study, we aimed to successfully isolate high-purity MK-Exo and develop a specialized freeze-drying and lyophilization method for improved long-term preservation of MK-Exo. Specifically, the stability of the lyophilized MK-Exo was evaluated using storage stability tests. Notably, lyophilized MK-Exo remained stable for at least 3 months under high temperature of 50°C and for at least 24 months under low temperatures of 2°C–8°C, preserving their physicochemical properties and biological activity. Conclusively, these findings provide a potential solution for ambient-temperature transportation of MK-Exo, facilitating their industrial-scale production.