In TFF, fluid is pumped across the face of a membrane with a defined pore size or molecular weight cutoff. Most of the fluid continues to circulate tangentially, while smaller molecules pass through the membrane and larger particles, including extracellular vesicles, are retained and concentrated. Because the flow runs parallel to the membrane rather than perpendicular to it, the membrane clogs more slowly than in a straight-through filter.
Ask which preparation method applies to the product and request supporting documentation. A method name alone does not establish the purity, structural integrity, or composition of a specific lot.
The membrane cutoff and processing parameters determine what ends up in the final preparation. Buyers evaluating an exosome or extracellular vesicle product should ask whether TFF, ultracentrifugation, or another method was used, and request the nanoparticle tracking analysis and marker data reflected on that lot's documentation.
These products are not FDA approved or licensed for any disease or condition. Information is for licensed healthcare professionals and is not medical or legal advice. FDA states there are no FDA-approved exosome products. Such products are generally regulated as biologic drugs under section 351, and decisions about purchase and clinical use belong to the physician working with their own regulatory counsel.
The concentration method a supplier uses can affect lot-to-lot consistency, which is relevant when a clinic is building its vendor qualification file.