Method and system for suspension culture
The present invention relates to cell culture in bioreactors, such as flexible cellbag bioreactors. More closely the invention relates to a method and system for determining the cell density in a bioreactor culture and for controlling the perfusion rate of a suspension culture of cells in a bioreactor, comprising measuring the oxygen uptake of primary mononuclear cells in a non-static bioreactor.
1. A method for regulating perfusion rate in a suspension culture of cells comprising primary mononuclear cells in a non-static bioreactor, comprising:
keeping the non-static bioreactor at a constant rocking rate of 1-25 rpm;
registering the dissolved oxygen concentration in the bioreactor;
determining the cell number of said primary mononuclear cells by a pre-determined correlation of the registered dissolved oxygen concentration with the cell number; and
automatically controlling the perfusion rate in response to the registered dissolved oxygen concentration,
wherein the pre-determined correlation is an inverse linear relationship, and
wherein no sampling of the contents of the bioreactor is performed to determine cell number.
2. The method according to claim 1 , wherein the dissolved oxygen concentration is measured by a sensor integrated in the bioreactor.
3. The method according to claim 1 , wherein the bioreactor is a flexible cell bag.
4. The method according to claim 1 , wherein the cells are T-cells.
5. The method according to claim 1 , wherein the rocking rate is 10-15 rpm and the bioreactor is a flexible cell bag.
6. The method according to claim 1 , wherein the rocking rate of the bioreactor is 10-15 rpm.
7. The method according to claim 2 , wherein the sensor is an optical sensor.
8. The method according to claim 1 , wherein the dissolved oxygen uptake is greater than 10%.
9. The method according to claim 1 , wherein the pre-determined correlation of the registered dissolved oxygen concentration (DO) with the cell number is defined by linear relationships:
DO=− 1.58 E -06*cell density+90.01 at 15 rpm and 6° angle; or
DO=− 2.88 E -06*cell density+89.81 at 10 rpm and 6° angle.
10. The method according to claim 1 , wherein controlling the perfusion rate in response to the registered dissolved oxygen concentration comprises adjusting pump rates without operator input.
11. The method according to claim 10 , wherein the pump rates control an amount of media perfused in in the non-static bioreactor.