Comparison of methods for isolating exosomes from bovine milk.

Four methods were evaluated for isolating exosomes from bovine milk: (1) ExoQuick precipitation, (2) ultracentrifugation with ExoQuick precipitation, (3) ultracentrifugation with density gradient centrifugation, and (4) human milk exosome isolation. Methods 1 and 4 failed due to differences between bovine and human milk. Exosomes were efficiently isolated by ultracentrifugation with either ExoQuick precipitation (method 2) or density gradient centrifugation (method 3). The highest yield of exosomes was achieved using ultracentrifugation with ExoQuick precipitation, whereas higher quality exosome isolation with intact morphological structures was achieved by ultracentrifugation with density gradient centrifugation.