Cell expansion vessel systems and methods
A method includes introducing a suspension including cells suspended in a cell culture medium through a feed port or a drain port into a cavity of a cell culture vessel, the suspension being in an amount sufficient to cover a gas permeable, liquid impermeable membrane positioned at a bottom of the cell culture vessel, the feed port being disposed through a surface of the cell culture vessel and configured to permit additional cell culture medium into the cavity, and the drain port being disposed through the surface of the cell culture vessel and configured to permit removal of the cells, cell culture medium, and used cell culture medium from the cavity, allowing the cells to settle on the gas permeable, liquid impermeable membrane by gravity, removing the used cell culture medium through the drain port and introducing the additional cell culture medium through the feed port such that a constant volume is maintained in the cell culture vessel until the cells expand to a desired cell density, wherein the removing and introducing are performed subsequent to allowing the cells to settle on the gas permeable, liquid impermeable membrane, resuspending the cells in the cell culture medium in the cell culture vessel, wherein the resuspending is performed after the desired cell density is attained, and removing the resuspended cells and the cell culture medium through the drain port.
1. A method, comprising:
introducing a suspension comprising cells suspended in a cell culture medium through at least a feed port or a drain port into a cavity of a cell culture vessel, the suspension being in an amount sufficient to cover a gas permeable, liquid impermeable membrane positioned at a bottom of the cell culture vessel, the feed port configured to permit additional cell culture, medium into the cavity, and the drain port configured to permit removal of the cells, cell culture medium, and used cell culture medium from the cavity;
allowing the cells to settle on the gas permeable, liquid impermeable membrane by gavity;
perfusing the cells with the cell culture medium, wherein the perfusing comprises
removing the used cell culture medium through the drain port and introducing the additional cell culture medium through the feed port such that a constant volume is maintained in the cell culture vessel until the cells expand to a desired density, wherein the removing and introducing are performed subsequent to allowing the cells to settle on the gas permeable, liquid impermeable membrane;
resuspending the cells in the cell culture medium in the cell culture vessel, wherein the resuspending is performed after the desired cell density is attained; and
removing the resuspended cells and the cell culture medium through the drain port.
2. The method of claim 1 , wherein removing the used cell culture medium comprises removing impurities, cell culture byproducts, or a combination thereof from within the cell culture vessel.
3. The method of claim 1 , wherein the allowing the cells to settle to the gas permeable, liquid impermeable membrane, the removing the used cell culture medium, and the introducing the additional cell culture medium comprise positioning the cell culture vessel such that the gas permeable, liquid impermeable membrane is level to allow even distribution of cells.
4. The method of claim 1 , wherein the resuspending of the cells in the cell culture medium comprises oscillating the cell culture vessel through a defined angle for a period of time.
5. The method of claim 1 , comprising sampling a homogeneous mixture of the cells within the cell culture vessel via the drain port to monitor cell growth, wherein the drain port is a filter-free port disposed through a wall of the cell culture vessel at a position at least partially below a surface of the cell culture medium within the cell culture vessel and at or above the gas permeable, liquid impermeable membrane, and wherein the sampling comprises tilting the cell culture vessel toward the drain port.
6. The method of claim 1 , wherein the removing of the resuspended cells and the cell culture medium through the drain port comprises tilting the cell culture vessel to minimize a hold-up volume.
7. The method of claim 1 , wherein the cell culture medium within the cell culture vessel extends from the gas permeable, liquid impermeable membrane to a height within a range of 0.3 cm to 2 cm of medium.
8. The method of claim 1 , wherein a ratio of cell culture medium volume per surface area of the gas permeable, liquid impermeable membrane is below a threshold value.
9. The method of claim 1 , wherein a headroom space above the cell culture medium within the cell culture vessel has a height that is approximately equal to a height of the cell culture medium relative to the gas permeable, liquid impermeable membrane.
10. A method, comprising:
introducing a suspension comprising cells suspended in a cell culture medium through at least a feed port or a drain port into a cavity of a cell culture vessel, the suspension being in an amount sufficient to cover a gas permeable, liquid impermeable membrane positioned at a bottom of the cell culture vessel, the feed port being disposed through a surface of the cell culture vessel and configured to permit additional cell culture medium into the cavity, and the drain port being disposed through a surface of the cell culture vessel and configured to permit removal of the cells, cell culture medium, and used cell culture medium from the cavity;
allowing the cells to settle on the gas permeable, liquid impermeable membrane by gravity;
perfusing the cells with the cell culture medium, wherein the perfusing comprises introducing the additional cell culture medium through the feed port while simultaneously or nearly simultaneously removing the used cell culture medium from the cell culture vessel via the drain port to maintaining a constant volume within the cell culture vessel until the cells expand to a desired cell density, wherein the perfusing is performed subsequent to allowing the cells to settle on the gas permeable, liquid impermeable membrane;
sampling the cells via the drain port to determine whether the desired cell density is reached;
repeating, upon determining that the desired cell density has not been reached, the perfusing of the cells until the desired cell density is reached;
resuspending the cells in the cell culture medium in the cell culture vessel, wherein the resuspending is performed after the desired cell density is reached; and
removing the resuspended cells and the cell culture medium through the drain port.
11. The method of claim 10 , wherein the sampling comprises:
stopping the perfusing of the cells;
resuspending the cells in the cell culture medium;
removing a homogeneous sample of the resuspended cells via the drain port determine whether the desired cell density has been reached; and
waiting, upon determining that the desired cell density has not been reached, for a waiting period for the cells to settle to the gas permeable, liquid impermeable membrane, wherein the perfusing is not initiated until the cells have sufficiently settled at or beneath the drain port.
12. The method of claim 11 , wherein resuspending the cells in the cell culture medium comprises oscillating the cell culture vessel about one or more horizontal axis of the cell culture vessel to generate a wave within the cavity of the cell culture vessel to create a homogenous mixture of the cells and the additional cell culture medium, wherein the cell culture vessel comprises a structure with sufficient headspace configured to facilitate generation of the wave.
13. The method of claim 10 , wherein the drain port is, a filter-free port disposed through a wall of the cell culture vessel at a position at least partially below a surface of the cell culture medium within the cell culture vessel and at or above the gas permeable, liquid impermeable membrane.
14. The method of claim 10 , wherein the drain port is sized such that an inhaling velocity used to remove the used cell culture medium via the drain port creates a suction force on the cells within the cell culture vessel that is less than a gravitational force pulling the cells to the gas permeable, liquid impermeable membrane.
15. The method of claim 10 , comprising concentrating the suspension of cells of the desired cell density such that the suspension of cells of the desired cell density comprises a smaller volume, wherein the concentrating comprises discontinuing the introduction of additional cell culture medium via the feeding port and continuing the removing of the used cell culture medium via the drain port, and wherein the removing of the cells comprises removing the concentrated cells.
16. The method of claim 10 , wherein a ratio of cell culture medium volume per surface area of the gas permeable, liquid impermeable membrane is below a threshold value.