Buoy Suspension Fractionation System

• US 20090014391A1
• Filed: 04/11/2008
• Published: 01/15/2009
• Est. Priority Date: 05/03/2002
• Status: Active Grant

• Current Assignee: Hanuman, LLC, Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Hanuman, LLC, Biomet Biologics LLC (Zimmer Biomet Holdings, Inc.)
• Inventors: Leach, Michael D., Dorian, Randel, Hoeppner, Jacy C.
• Granted Patent: US 7,992,725 B2
• Time in Patent Office: Days
• US Class Current: 210/740
• CPC Class Codes: A61K 35/00 Medicinal preparations containing materials or reaction products thereof with undetermined constitution
• CPC Class Codes: A61M 1/029 Separating blood components present in distinct layers in a container, not otherwise provided for containers for storing blood or blood components A61J1/05; sampling or analysing blood by separating blood components G01N33/491
• CPC Class Codes: A61M 1/3693 using separation based on different densities of components, e.g. centrifuging
• CPC Class Codes: A61M 2202/0427 Platelets; Thrombocytes
• CPC Class Codes: B01D 21/0012 Settling tanks making use of filters, e.g. by floating layers of particulate material
• CPC Class Codes: B01D 21/26 Separation of sediment aided by centrifugal force or centripetal forcecentrifuges B04B; cyclones B04C
• CPC Class Codes: B01D 21/262 by using a centrifuge
• CPC Class Codes: B01D 2221/10 Separation devices for use in medical, pharmaceutical or laboratory applications, e.g. separating amalgam from dental treatment residues apparatus for dental treatment A61C17/065
• CPC Class Codes: B01L 2200/026 Fluid interfacing between devices or objects, e.g. connectors, inlet details
• CPC Class Codes: B01L 2400/0633 with moving parts
• CPC Class Codes: B01L 3/50215 using a float to separate phases
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80

Abstract

A separator that uses centrifugation to fractionate a suspension such as blood comprises a separation container and a buoy. The buoy is carried in the separation container and has a tuned density that is configured to reach an equilibrium position in a suspension. The guide surface is carried on the buoy upper surface and is inclined to an accumulation position near a buoy perimeter. The buoy suspension fractionation system can be used in a method of isolating a fraction from a suspension, and in a method for re-suspending particulates for withdrawal.

Claims

1. A buoy suspension fractionation system, comprising:

a separation container and an access port through at least a portion of the separation container, the separation container is enclosed by a container wall, a container bottom a container top; and

,

a buoy in the separation container, the buoy having a tuned density and configured to reach an equilibrium position in a suspension, the buoy comprising a buoy upper surface and a buoy sidewall defining a height, a transverse dimension, and a perimeter, the buoy further comprising;

a guide surface on the buoy upper surface, the guide surface having a collection space above the buoy upper surface and the guide surface being inclined to an accumulation position near the buoy perimeter.

2. The buoy suspension fractionation system as in claim 1 wherein the buoy includes a maximum transverse dimension configured to be positioned near an equilibrium interface between two separated fractions of the suspension and substantially defining a buoy maximum cross-sectional area.

3. The buoy suspension fractionation system as in claim 2 wherein movement of the buoy near an equilibrium interface results in substantially maximum change in displacement of a fractionated suspension below the equilibrium interface and substantially maximum change in displacement of a fractionated suspension above the equilibrium interface relative to change in axial orientation of the buoy relative to the interface.

4. The buoy suspension fractionation system as in claim 1 wherein the guide surface is inclined relative to the buoy sidewall for a distance of more than about two-thirds the buoy transverse dimension.

5. The buoy suspension fractionation system as in claim 1 wherein the guide surface is inclined relative to the buoy sidewall substantially throughout a length of the guide surface.

6. The buoy suspension fractionation system as in claim 1 wherein the guide surface is inclined in relation to the buoy sidewall at an average angle of about 10 degrees to about 70 degrees.

7. The buoy suspension fractionation system as in claim 1 wherein the guide surface is substantially planar.

8. The buoy suspension fractionation system as in claim 1 wherein the guide surface is inclined substantially outwardly toward the buoy perimeter.

9. The buoy suspension fractionation system as in claim 8, wherein the guide surface extends from a first edge of the buoy perimeter along the transverse dimension and substantially through a center of the buoy to a second edge of the buoy perimeter.

10. The buoy suspension fractionation system as in claim 1 wherein the guide surface defines contours.

11. The buoy suspension fractionation system as in claim 1, further comprising a collection port communicating with the access port and communicating with the collection space above the buoy upper surface.

12. The buoy suspension fractionation system as in claim 1 further comprising,

an isolator coupled to the buoy, the isolator comprising a spacer to position the isolator apart from the buoy to create a collection area.

13. The buoy suspension fractionation system as in claim 12 further comprising,

a withdraw port carried on the isolator communicating with the access port and the collection area.

14. The buoy suspension fractionation system as in claim 12 wherein the isolator has an isolator volume and the buoy has a buoy volume;

wherein a first combination of both of the isolator volume and the buoy volume below an equilibrium interface is greater than a second combination of both of the isolator volume and the buoy volume above the equilibrium interface.

15. The buoy suspension fractionation system as in claim 12 wherein the isolator is configured to move from an open position apart from the buoy to a closed position near the buoy.

16. The buoy suspension fractionation system as in claim 12 wherein the isolator has an isolator volume and the buoy has a buoy volume;

wherein the isolator volume is substantially less than the buoy volume.

17. The buoy suspension fractionation system as in claim 12 wherein the isolator has collection openings.

18. The buoy suspension fractionation system as in claim 12 further comprising,

a collection vent passage through the isolator to equalize pressure when fluid is withdrawn from the collection area.

19. The buoy suspension fractionation system as in claim 18 further comprising,

a collection valve communicating with the collection vent.

20. The buoy suspension fractionation system as in claim 18 further comprising,

a collection vent tube communicating with the collection vent and air above where a suspension would be located in a separation container.

21. The buoy suspension fractionation system as in claim 12 further comprising,

a mechanical agitator carried in the collection area.

22. The buoy suspension fractionation system as in claim 1 wherein the collection port is located near the buoy perimeter.

23. The buoy suspension fractionation system as in claim 1 further comprising,

a precision collection region interposed between the guide surface and the buoy perimeter.

24. The buoy suspension fractionation system as in claim 1 wherein when the separation container is at rest, the buoy perimeter and the container wall form an interference fit holding the buoy at a position in the separation container and when the separation container is centrifuged a clearance is defined between the buoy perimeter and the container wall allowing the buoy to move within the separation container and a material to pass between the buoy perimeter and the container wall.

25. The buoy suspension fractionation system as in claim 1 wherein the separation container is a separation tube.

26. A buoy for a suspension fractionation system, comprising:

a buoy having a tuned density and configured to reach an equilibrium point in a suspension, the buoy comprising a buoy upper surface, a buoy sidewall defining a height, a buoy transverse dimension, and a buoy perimeter, the buoy further comprising;

a collection port communicating with a collection space above the buoy upper surface;

a guide surface on the buoy upper surface, the guide surface being substantially planar and inclined relative to the buoy sidewall for a distance of more than two thirds the buoy transverse dimension; and

,

an isolator coupled to the buoy, the isolator comprising a spacer to position the isolator apart from the buoy to create a collection compartment, between the isolator and the buoy upper surface and a withdraw port carried on the isolator communicating with the collection port.

27. The buoy suspension fractionation system as in claim 26 wherein the buoy transverse dimension includes a cross-sectional area of the buoy configured near an equilibrium interface to be substantially a maximum cross-sectional area of the buoy.

28. The buoy suspension fractionation system as in claim 27 wherein movement of the buoy near an equilibrium interface results in substantially maximum change in displacement of a fraction below the equilibrium interface and substantially maximum change in displacement of a fraction above the equilibrium interface relative to an axis of buoy relative to the equilibrium interface.

29. The buoy system as in claim 26 further comprising,

a collection vent on the isolator to equalize pressure when fluid is withdrawn from the collection space.

30. The buoy system as in claim 26 further comprising,

a collection valve communicating with the collection port.

31. The buoy suspension fractionation system as in claim 26 further comprising,

a collection vent tube communicating with the collection vent above where a suspension would be located in a separation container.

32. The buoy system as in claim 26 wherein the collection port is located near the buoy perimeter.

33. The buoy system as in claim 26 wherein the isolator is configured to move from an open position apart from the buoy to a closed position near the buoy.

34. The buoy system as in claim 26 wherein the isolator has collection openings.

35. The buoy system as in claim 26 further comprising,

a precision collection region interposed between the guide surface and the buoy perimeter.

36. The buoy system as in claim 26 wherein the guide surface defines contours.

37. The buoy system as in claim 26 wherein an isolator volume is substantially less than a buoy volume.

38. The buoy system as in claim 26 wherein a first isolator volume and a first buoy volume combined below an equilibrium interface is greater than a second isolator volume and a second buoy volume combined above the equilibrium interface.

39. A buoy for a suspension fractionation system, comprising:

a buoy having a tuned density and configured to reach an equilibrium position in a suspension, the buoy comprising a buoy top, buoy bottom, and a buoy sidewall defining a buoy height and a buoy perimeter, the buoy further comprising;

a guide means for conveying particles down an incline toward an equilibrium interface.

40. The buoy as in claim 39 further comprising,

a collection means for removing a selected fraction from a collection space that is located near the buoy.

41. The buoy as in claim 39 further comprising,

isolation means for creating a collection compartment for an isolated fraction, the isolation means being spaced apart from the buoy and coupled to the buoy.

42. The buoy as in claim 41 further comprising,

withdraw means for withdrawing the isolated fraction from the collection compartment.

43. The buoy as in claim 39 further comprising,

a precision collection means for collecting a precise fraction of the selected fraction.

44. A method of isolating and withdrawing a fraction from a fractionated suspension using a buoy, comprising:

filling a separation container with a suspension, the separation container having a buoy with a tuned density;

centrifuging the separation container to cause the suspension to separate into fractions of varying densities;

allowing the buoy in the separation container to reach an equilibrium within the fractions;

concentrating particulates using a guide surface of the buoy that is inclined to an accumulation position near a perimeter of the buoy;

conveying the particulates along the guide surface of the buoy to a collection space; and

,

withdrawing a desired fraction.

45. The method as in claim 44, further comprising,

effecting a substantially maximum change in displacement of a volume of fractionated suspension below an equilibrium interface and effecting a substantially maximum change in displacement of a volume of fractionated suspension above the equilibrium interface relative to axial displacement of the buoy having a substantially maximum transverse dimension cross-sectional area of the buoy near the equilibrium interface.

46. The method as in claim 44, further comprising:

filling the separation container through an access port and withdrawing the desired fraction through the access port.

47. The method as in claim 44 further comprising,

isolating a separated fraction in a collection compartment between the guide surface of the buoy and an isolator coupled to the buoy.

48. The method as in claim 47 further comprising,

withdrawing the isolated fraction through a withdraw port through the isolator.

49. The method as in claim 44 wherein the guide surface is inclined relative to a buoy sidewall substantially throughout a length of the guide surface.

50. The method as in claim 44 wherein conveying particulates along the guide surface includes conveying the particulates along a substantially flat path to the collection space.

51. The method as in claim 44 wherein the particulates are selected from the group consisting of platelets, stromal cells, stem cells and white blood cells.

52. A method for isolating and re-suspending particulates for withdrawal from a buoy suspension fractionation system, comprising:

filling a separation container with a suspension, the separation container having a buoy with a tuned density;

centrifuging the separation container to cause the suspension to separate into fractions of varying densities;

allowing the buoy in the separation container to reach an equilibrium within the fluid between two or more fractions;

isolating an isolated fraction in a collection compartment between the guide surface of the buoy and an isolator coupled to the buoy;

re-suspending the isolated fraction within the collection compartment by moving an agitator in the separation container to agitate the isolated fraction to create a more uniform isolated fraction; and

,

withdrawing the isolated fraction from the collection compartment.

53. The method as in claim 52 further comprising,

withdrawing a first increment of an isolated fraction from a collection compartment to create an air bubble to serve as the agitator.

54. The method as in claim 52 further comprising,

providing a mechanical agitator in the collection compartment to serve as the agitator.

55. The method as in claim 52 further comprising,

concentrating particulates using a guide surface of the buoy, the guide surface being inclined to an accumulation position near a buoy perimeter;

and,

conveying the particulates along the guide surface of the buoy to a collection port.

56. The method as in claim 52 wherein the guide surface is inclined relative to a buoy sidewall substantially throughout the length of the guide surface.

57. The method as in claim 52 wherein the particulates are selected from the group consisting of platelets, stromal cells, and white blood cells.

58. The method as in claim 52 further comprising,

withdrawing a fraction located above the isolator prior to withdrawing a first increment.