Vessels and spinner flasks with reduced impeller wobble for culturing cells

1. A vessel for culturing cells, comprising:

a vessel body having a top portion, a bottom portion comprising a bottom interior surface, and a cylindrical sidewall;

an impeller assembly inside the vessel body comprising a top portion rotatably coupled to the top portion of the vessel body, the impeller assembly having a plurality of planar blades, a central axis, a flexible shaft extending down from the top portion of the impeller assembly, a magnet receptacle molded within the plurality of planar blades, a magnet within the magnet receptacle, and an impeller o-ring, where each of the plurality of planar blades comprises a bottom surface and the impeller o-ring is coupled to each of the bottom surfaces of the planar blades; and

a plurality of positioning nubs coupled to the bottom interior surface of the vessel body, spaced from an inside edge of the impeller o-ring.

2. The vessel of claim 1 , wherein the plurality of positioning nubs is three positioning nubs, each nub spaced circumferentially from each of the other nubs at an approximately equal distance.

3. The vessel of claim 2 , wherein each of the nubs have a conical shape.

4. The vessel of claim 2 , wherein each of the nubs have a cylindrical shape.

5. The vessel of claim 1 , wherein the vessel body comprises a polymeric material.

6. The vessel of claim 1 , wherein the plurality of planar blades is four planar blades coupled to the flexible shaft, each blade disposed at 90 degrees relative to the blades adjacent to it.

7. The vessel of claim 1 , further comprising:

a plurality of baffles, each baffle integral with the sidewall of the vessel body originating at the bottom interior surface and extending vertically to a predetermined distance up the sidewall.

8. The vessel of claim 7 , wherein each baffle terminates in an elliptical shape.

9. The vessel of claim 7 , wherein the plurality of baffles is three baffles, each baffle is spaced an equal distance from each of the other baffles around a perimeter defined by the cylindrical sidewall.

10. The vessel of claim 1 , wherein the vessel body further comprises a radius measured by the distance from the central axis to the sidewall, and further wherein at least one of the blades extends about 50 to 95% of the radius of the vessel body toward the cylindrical sidewall.

11. The vessel of claim 1 , wherein each blade comprises a bottom edge spaced from about 0.05 inches to about 0.5 inches from the bottom interior surface.

12. The vessel of claim 1 , wherein the impeller assembly is sealed inside the vessel body.

13. A vessel for culturing cells, comprising:

a vessel body having a top portion, a bottom portion comprising a bottom interior surface, and a cylindrical sidewall;

an impeller assembly inside the vessel body comprising a top portion rotatably coupled to the top portion of the vessel body, the impeller assembly having a plurality of planar blades, a central axis, a flexible shaft extending down from the top portion of the impeller assembly, a magnet receptacle molded within the plurality of planar blades, a magnet within the magnet receptacle, and an impeller o-ring, where each of the plurality of planar blades comprises a bottom surface and the impeller o-ring is coupled to each of the bottom surfaces of the planar blades; and;

a plurality of positioning nubs coupled to the bottom interior surface of the vessel body, spaced from an inside edge of the impeller o-ring; and

a center nub coupled to the bottom interior surface of the vessel body coincident with the central axis of the impeller assembly.

14. The vessel of claim 13 , further comprising a plurality of baffles, each baffle integral with the sidewall of the vessel body,

wherein each baffle is spaced an equal distance from each of the other baffles around a perimeter defined by the cylindrical sidewall.

15. The vessel of claim 13 , wherein the vessel body further comprises a radius measured by the distance from the central axis to the sidewall, and further wherein at least one of the blades extends about 50 to 95% of the radius of the vessel body toward the cylindrical sidewall.

16. The vessel of claim 13 , wherein the plurality of positioning nubs is three positioning nubs, each nub spaced circumferentially from each of the other nubs at an approximately equal distance.

17. The vessel of claim 16 , wherein each of the nubs have a conical shape.

18. The vessel of claim 13 , wherein the center nub has a cylindrical shape or a conical shape.

19. The vessel of claim 13 , wherein the vessel body is a polymeric material.

20. The vessel of claim 13 , wherein the plurality of planar blades is four planar blades coupled to the flexible shaft, each blade disposed at 90 degrees relative to the blades adjacent to it.