Exosome RNA Exosome RNA Research & Industry News
Extracellular vesicles (EVs) are tiny membrane-bound particles released by cells that carry proteins, nucleic acids, lipids, and other biologically active molecules. Their ability to transport molecular cargo has made EVs increasingly important for research into drug delivery, diagnostics, and therapeutics.
A research team at the Shanghai University of Traditional Chinese Medicine evaluated a new approach for isolating EVs that could help overcome some of the limitations of existing methods. The researchers focused on extracellular vesicles derived from Portulaca oleracea L., commonly known as purslane.
Challenges in extracellular vesicle isolation
Ultracentrifugation is a widely used method for isolating EVs, but it requires expensive equipment, has relatively low throughput, and high centrifugal forces can potentially damage vesicles. Tangential flow filtration (TFF) is more suitable for larger-scale processing, but EVs can adhere to membranes and tubing, reducing recovery. Small molecules can also become concentrated with the EVs, decreasing purity.
To address these challenges, the researchers evaluated an automated method combining tangential flow filtration with electrophoresis, called TFFE. They compared the technique with ultracentrifugation, polyethylene glycol precipitation, and size exclusion chromatography.
Combining filtration and electrophoresis
The TFFE process uses three filtration stages. An initial 0.45 μm filter removes plant debris and large particles, which is particularly important for fiber-rich purslane extracts. A 0.22 μm filtration step then removes smaller molecules while retaining and concentrating EVs.
During filtration, material accumulating on the membrane creates a layer that effectively reduces its pore size. The researchers found that this helped retain EVs approximately 150 nm in size.
In the final purification stage, a 0.1 μm membrane is combined with electrophoresis. An electric field helps capture EVs on the membrane surface rather than relying entirely on physical filtration through membrane pores.
Toward scalable EV production
Developing efficient isolation methods is increasingly important as plant-derived extracellular vesicles are investigated for pharmaceutical and biomedical applications. Techniques that work for small laboratory samples may be too slow, expensive, or inefficient for large-scale manufacturing.
