Tangential flow filtration (TFF), or crossflow filtration (CFF), is an efficient and fast technique used in diafiltration, concentration, and fractionation of biomolecules. In this technique, the feed solution is tangentially passed along a filter membrane. Pressure differences drive molecules that are smaller than the membrane pore size through the filter. The retained larger components, or retentate, pass along the TFF filter surface and flow back to a feed reservoir. A key advantage of TFF is that it prevents “filter cake” formation to allow high liquid removal rates.
Filters for TFF systems are broadly classified according to filter configuration or pore size.
- Filter configuration
The two main TFF filter configurations are:
- Hollow fiber filters: These filters feature a membrane that forms a set of parallel hollow fibers. Feed streams pass through the fiber lumens as the permeate gets collected from outside the fibers. You can classify cartridges according to fiber length, number of fibers, or filter pore size.
- Cassette filters: Cassette filters comprise a housing with many flat sheets of membrane, held apart from each other by support screens. Feed streams pass into the space between sheets and permeate is collected from the opposite side of the sheets. Our tangential flow filtration systems can handle both hollow fiber filters and cassette filters.
- Filter pore size
The two major classifications according to filter pore size include:
- Microfiltration filters: These are filters with a pore size of 0.1 μm and larger. The most common pore size in CFF and TFF microfilters ranges from 0.1 to 1 μm. Use these filters to separate cultured cells from growth media and remove particles in the bioprocessing of pharmaceuticals.
- Ultrafiltration filters: Ultrafiltration membranes have smaller pore sizes than microfiltration membranes. The nominal molecular weight cutoff (NMWC) is their key characteristic. These filters support use in various applications, such as concentration and fractionation of protein streams. Pore sizes range from NMWC of 1000 to 750 000.
Single-use hollow fiber cartridges eliminate device preparation steps like sterilization and wetting for simple and speedy drug development. Our ReadyToProcess™ hollow fiber cartridges come with ReadyMate™ single-use connectors that support aseptic connection to other components such as bioprocess containers and tubing.
TFF filter FAQs
Below are answers to some frequently asked questions about TFF filters.
What is a hollow fiber filter?
Also known as cartridge filters, these are TFF filters that comprise sets of parallel hollow fibers.
How does a hollow fiber filter work?
Feed streams pass through the fiber lumens, enabling the collection of permeate from outside the fibers.
When should I use a hollow fiber filter?
Use hollow fiber TFF filters for ultrafiltration, diafiltration, and microfiltration processes.
What pore size is best for my TFF application?
We recommend the following TFF filter pore sizes for the applications listed. You can learn more in our selection handbook for hollow fiber cartridges and systems.
- Bacterial/pyrogen removal: 10 000 NMWC
- Protein concentration: 3000; 5000; 10 000; 30 000 NMWC
- Enzyme concentration: 10 000; 30 000; 50 000 NMWC
- Virus concentration/purification/ removal: 100 000; 300 000; 500 000; 750 000 NMWC
- Protein/antigen recovery from fermentation broth: 500 000; 750 000 NMWC.
- Bacterial cell concentration: 500 000 NMWC
- Red blood cell stroma removal: 500 000 NMWC
- Hemoglobin concentration: 5000; 10 000 NMWC
- Peptide concentration: 1000; 3000 NMWC
- Protein/antigen recovery from fermentation broth: 0.1, 0.2, 0.45, 0.65 μm
- Bacterial cell concentration: 0.1, 0.2 μm
- Insect cell concentration: 0.1, 0.2 μm
- Mammalian cell concentration: 0.2, 0.45, 0.65 μm
- Yeast concentration: 0.1, 0.2, 0.45 μm
- Continuous cell culture perfusion: 0.1, 0.2, 0.45 μm
- Red blood cell washing: 0.45, 0.65 μm
- Red blood cell stroma removal: 0.1 μm