Isolation of Extracellular Vesicle (EV)-Rich Plasma from Human Blood and Detection of Activated Clotting Time

To begin, centrifuge the human blood at 120 G for 20 minutes at room temperature to remove the blood cells. Then transfer the upper half of the supernatant to a new tube. Next, centrifuge the platelet rich plasma to remove the platelets, and transfer the upper half of the supernatant to a new tube.

Then remove the cell debris by centrifuging the platelet to our plasma at 13, 000 G for two minutes. Transfer the upper half of the supernatant to a new tube. Turn on the clot analyzer to detect extracellular vesicle, or EV activated clotting time, and preheat the instrument to 37 degrees Celsius.

Install the disposable probe and test cup. Then start the quality control procedure of the machine. After the quality control run, enter sample information into the system.

Then add 200 microliters of EV-rich plasma to the test cup, followed by 20 millimolar, 170 microliters of calcium chloride. Click the start button, close the cover, and allow the probe to detect the change in sample resistance. The unqualified EV samples exhibit a distinct cluster with a slightly larger particle size near the gate of EV.In contrast, qualified EV-rich samples showed most signals within the gate of EV as a single group.

An increase in EV concentration shortened EV activated clotting time, while a decrease in EV concentration prolonged EV activated clotting time. EV-rich plasma samples from patients with preeclampsia, hip fractures, and lung cancer had significantly shorter EV activated clotting time compared to healthy volunteers.