Bioreactor & Fermentor

Bioreactor & Fermentor

Spin filter

Spin filters are retention devices designed to keep the cells inside the vessel in perfusion cultivation.
Combined for example with low-shear marine impellers they can be used for suspension cells and cells growing on microcarriers.
The spin filter consists of a screened cage with very small pore size that keeps cells isolated outside the cage.
The cage rotates, attached to the concentric impeller shaft, while inside of it a dip tube continuously withdraws the filtered, cell-free culture broth.
For perfusion culture, an addition tube outside the cage provides a steady supply of fresh medium so that the working volume remains at a constant level.
This mechanism is ideal for production of secreted proteins: It keeps the harvested medium free of cells, which simplifies downstream purification.
Over time, however, the spin filter screen material will tend to clog and require replacement, thus limiting cultivation time.