Method for exosome separation and extraction by stacked centrifugal filtration

A method for exosome separation and extraction, comprising:

• 1) adding an incubation buffer into a sample to be tested, the volume of the incubation buffer being 0.1-5 times that of the sample, and adding an amount of protease K to make the final concentration of protease K be 0.2 mg/mL-2.0 mg/mL at the same time, mixing and incubating at room temperature;
• 2) transferring all liquid in step 1) into a filter tube of a stacked centrifugal filtration device for exosome separation and extraction, positioning the stacked centrifugal filtration device in a centrifuge for centrifugation, and collecting the retentate in an ultrafiltration tube to obtain the exosomes;
• wherein the stacked centrifugal filtration device for exosome separation and extraction comprises:
• a filter tube comprising a filter membrane at the bottom of the filter tube, a primary support edge provided with a first air passage at a top tube opening of the filter tube, and a primary filter tube cavity within the filter tube,
• an ultrafiltration tube arranged outside of the filter tube comprising:
• an ultrafiltration membrane at the bottom of the ultrafiltration tube,
• a secondary support edge provided with a second air passage at a top tube opening of the ultrafiltration tube, and a secondary filter tube cavity within the ultrafiltration tube and below the filter tube,
• a collecting tube arranged outside of the ultrafiltration tube comprising:
• a collecting tube cavity within the collecting tube and below the ultrafiltration tube, and
• a cap provided at the top of the collecting tube,
• when the stacked centrifugal filtration device is capped, the primary support edge is pressed on the secondary support edge, the secondary support edge is pressed on a top tube opening of the collecting tube, and the primary filter tube cavity and the secondary filter tube cavity are connected to the atmosphere through the first and second air passages;
• and
• wherein:
• both left and right sides of the ultrafiltration tube wall are planar and inclining towards a middle part;
• a secondary filter tube cavity with a V-shape cross section is formed by the two planar walls;
• and
• at least one window for the ultrafiltration membrane is arranged on one or both sides of the two planar walls.