To begin, take cultured mouse ovarian epithelial cancer cells. Remove the culture medium from the Petri dishes and wash twice with DPBS. Add 20 milliliters of Dulbecco's Modified Eagle Medium without FBS and penicillin-streptomycin solution.
Incubate at 37 degrees Celsius and 5%carbon dioxide for 48 hours. Then collect the cell culture supernatant from 20 Petri dishes of 15-centimeter diameter. Centrifuge at 300 G for 10 minutes at four degrees Celsius and collect the supernatant.
Centrifuge the supernatant at 2, 000 G for 10 minutes at four degrees Celsius, and collect the supernatant to remove cellular debris. Now turn on the vacuum pump and connect it to the air inlet of the vacuum filtration system. Filter the supernatant through the 0.22-micron polyethersulfone membrane to remove vesicles or impurities larger than 0.22 microns.
Add 15 milliliters of the filtered supernatant to the inner tube of the 100-kilodalton ultrafiltration tube. Centrifuge at 3, 500 G for 10 minutes at four degrees Celsius. Then remove the liquid from the outer tube.
Next, collect the liquid from the inner tube. Add one milliliter of DPBS to the inner tube. Pipette repeatedly to resuspend exosomes, and then collect them.
Centrifuge the liquid at 10, 000 G for 60 minutes at four degrees Celsius. Transfer the supernatant to a six-milliliter quick-snap centrifuge tube and seal it with a heat sealer. Cut open the tube after ultracentrifuging the supernatant for two hours.
Once the supernatant is removed, resuspend the pellet in 100 microliters of DPBS to obtain the exosome solution.
