Tangential flow filtration device for perfusion applications

1. A perfusion process for harvesting target proteins from a liquid feed comprising the target proteins and host cells, said perfusion process comprising:

a) providing: i) a perfusion filter element sheet comprising:

a feed channel having a microporous membrane having a mean pore size of at least about 0.65 μm; and a woven feed spacer comprising woven fibers and having an open area of at least about 35%, the woven fibers having an average fiber diameter of 270 μm to 500 μm and ii) a bioreactor comprising host cells and a target protein;

b) delivering from the bioreactor the liquid feed comprising target proteins and host cells to a feed channel of at least one perfusion filter element sheet; and

c) separating the target proteins from the host cells in the at least one perfusion filter element sheet to create a permeate comprising target proteins and a retentate comprising recovered host cells and returning at least a portion of the recovered host cells to the bioreactor.

2. The perfusion process of claim 1 , wherein said permeate comprises harvested target proteins.

3. The perfusion process of claim 1 , wherein the target proteins are monoclonal antibodies.

4. The perfusion process of claim 1 , wherein the host cells are CHO cells.

5. The perfusion process of claim 1 , wherein the target proteins are separated from the host cells by tangential flow filtration (TFF).

6. The perfusion process of claim 1 , further comprising recovering the target proteins from the at least one filter element.

7. The perfusion process of claim 6 , wherein at least about 80% of the target proteins are recovered from the liquid feed at a harvest throughput of at least about 500 L/m 2 of the filter element.

8. The perfusion process of claim 6 , wherein at least about 80% of the target proteins are recovered from the liquid feed at a harvest throughput of at least about 1000 L/m 2 of the filter element.

9. The perfusion process of claim 6 , wherein at least about 90% of the target proteins are recovered from the liquid feed at a harvest throughput of at least about 500 L/m 2 of the filter element.

10. The perfusion process of claim 6 , wherein at least about 90% of the target proteins are recovered from the liquid feed at a harvest throughput of at least about 1000 L/m 2 of the filter element.

11. The perfusion process of claim 6 , wherein at least about 95% of the target proteins are recovered from the liquid feed at a harvest throughput of at least about 500 L/m 2 of the filter element.

12. The perfusion process of claim 6 , wherein at least about 95% of the target proteins are recovered from the liquid feed at a harvest throughput of at least about 1000 L/m 2 of the filter element.

13. The perfusion process of any one of claim 1 , further comprising, supplying a volume of fresh media to the recovered host cells.

14. The perfusion process of claim 1 , wherein delivering the liquid feed to the feed channel of the at least one filter element and returning the recovered host cells to the bioreactor occurs on a continuous basis, the recovered host cells being the liquid feed of a subsequent perfusion process.

15. The prefusion process of claim 1 , wherein said mean pore size is from about 0.65 μm to about 10.0 μm.

16. The perfusion process of claim 1 , wherein said mean pore size is from about 0.65 μm to about 3.0 μm.

17. The perfusion process of claim 1 , wherein the open area of said feed spacer is from about 35% to about 55%.

18. The prefusion process of claim 1 , wherein the open area of said feed spacer is from about 35% to about 40%.