EasySep Hu EV (CD9) Pos Sel Kit

From STEMCELL Technologies, this kit enables isolation of human CD9+ extracellular vesicles (EVs) from plasma, serum, cell culture conditioned medium, and urine using immunomagnetic positive selection. The protocol is described as fast and easy-to-use and requires no columns, with the overall procedure taking less than 30 minutes. The kit is designed for processing 20 mL of biofluid.

EVs are targeted with an antibody recognizing the CD9 tetraspanin marker and labeled with magnetic particles, then separated using an EasySep™ magnet. Unwanted biofluid components are poured off while desired EVs remain in the tube. The kit contains a Selection Cocktail (a combination of monoclonal antibodies in PBS) and Releasable RapidSpheres™ (a suspension of magnetic particles in water); both components are stored at 2 - 8°C and not frozen, and are stable until the expiry date on the label. Following positive selection, particles should not be released from EVs, and the resulting fraction contains highly purified EVs ready for downstream applications such as DNA/RNA extraction, Western blot, or mass spectrometry.

For plasma samples, whole blood is centrifuged at 2000 x g for 10 minutes, then the plasma layer is centrifuged again at 2000 x g for 10 minutes, followed by 10,000 x g for 30 minutes to remove cellular debris and large vesicles; optional 0.2 μm filtration may be performed prior to isolation. Conditioned medium is centrifuged at 2000 x g for 10 minutes, then the supernatant at 10,000 x g for 30 minutes, with optional 0.2 μm filtration. Western blot analyses have shown positive isolation of EVs with the CD9 tetraspanin marker from human plasma and from mesenchymal stromal cell-conditioned medium.