Tangential flow filtration systems are designed specifically for filtering larger volumes of solution. In traditional filtration systems, fluid is directed toward the membrane with applied pressure.
When processing larger volumes, retained molecules can build-up on the surface of the membrane and slow, or block, filtration. In TFF, fluid is pumped tangentially along the surface of the membrane.
An applied pressure forces smaller molecules through the membrane, while larger molecules are swept along the surface of the membrane, which prevents the membrane from fouling.
The tangential flow filtration (TFF) products are suitable for concentrating and desalting proteins from cell culture supernatants and fermentation broths. The high flux, low binding Millipore membranes used in these devices provide high protein retention and recovery.
Pellicon XL Devices are available with a choice of either Durapore PVDF membrane (microporous), Ultracel regenerated cellulose membrane (ultrafiltration) or Biomax polyehtersulfone membrane (UF), and membranes for concentrating and desalting from 100 millilitres to 2 litres of protein-containing solution.
Compared to large stirred cell systems, Pellicon XL Devices offer better flow rates with less processing time. Additionally, the devices can be "docked" with the Labscale TFF pump system from Millipore without the need for tubing or clamps.
Pellicon 2 Mini-Cassettes are available with either regenerated cellulose, or polyethersulfone membranes for processing up to 10 litres of protein-containing solution. Larger cassette systems are available for processing 250 litres or more of solution.
The pace at which protein research is currently being conducted indicates that more efficient and rapid means of expressing and purifying proteins must be developed.
While there has been a consistent demand for the tools to purify proteins from whole cells or tissues, this technologically stable market continues to grow.
The increase in the number of biological therapeutics in clinical trials as well as the quest to elucidate the proteome have generated renewed interest in these techniques, which are fundamental to almost all sectors of life science research.
The advent of affinity chromatography and tagged purification systems several years ago was a tremendous boon for protein science.
Automated purification systems promise to minimise required expertise and increase the speed by which protein samples can be isolated and analysed, but researchers continue to struggle with basic issues such as sample purity, low yields and sample degradation.