Flow Focusing Method and System for Forming Concentrated Volumes of Microbeads, and Microbeads Formed Further Thereto

• US 20110081643A1
• Filed: 10/10/2008
• Published: 04/07/2011
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Sebastian Fournier-Bidoz, Warren Che Wor Chan
• Original Assignee: Sebastian Fournier-Bidoz, Warren Che Wor Chan
• Inventors: Fournier-Bidoz, Sebastian, Chan, Warren Che Wor
• Granted Patent: US 8,551,763 B2
• Time in Patent Office: Days
• US Class Current: 435/5
• CPC Class Codes: B01F 23/41 Emulsifying
• CPC Class Codes: B01F 33/3011 using a sheathing stream of a fluid surrounding a central stream of a different fluid, e.g. for reducing the cross-section of the central stream or to produce droplets from the central stream
• CPC Class Codes: B01F 33/453 using supported or suspended stirring elements
• CPC Class Codes: B01F 33/4534 using a rod for supporting the stirring element, e.g. stirrer sliding on a rod or mounted on a rod sliding in a tube
• CPC Class Codes: B01J 13/04 by physical processes, e.g. drying, spraying
• CPC Class Codes: B29C 48/2552 provided in the feeding, melting, plasticising or pumping zone, e.g. screw, barrel, gear-pump or ram
• CPC Class Codes: C08J 3/14 by precipitation from solutions C08J3/122 takes precedence
• CPC Class Codes: C08J 3/21 the polymer being premixed with a liquid phase
• CPC Class Codes: C12Q 1/701 Specific hybridization probes
• CPC Class Codes: C12Q 1/706 for hepatitis

Abstract

In a method and system for forming concentrated volumes of microbeads, a polymer solution and/or suspension includes a polymer dissolved and/or dispersed in a medium. Streams of a focusing fluid and of the polymer solution and/or suspension flow towards a fluid bath, and into intersection with one another, so &s to focus the polymer solution and/or suspension. The polymer solution and/or suspension stream forms microbeads in the fluid bath. Some of the focusing fluid is drawn from the fluid bath, so as to concentrate the microbeads in die fluid bath. The system includes a flow focusing apparatus and a liquid-containing cell. The focusing apparatus includes polymer and focusing nozzles. The cell contains the fluid bath and has an outlet port, through which the focusing fluid is drawn from the fluid bath.

Claims

1. A method of forming one or more concentrated volumes of microbeads, the method comprising the steps of:

(a) flowing a focused stream of a polymer solution and/or suspension towards a fluid bath, with the polymer solution and/or suspension comprising a polymer dissolved and/or dispersed in a medium;

(b) flowing a focusing stream of a focusing fluid towards the fluid bath, and into intersection with the focused stream;

(c) flowing the focusing stream and the focused stream from intersection with one another, so as to form the microbeads in the fluid bath; and

(d) flowing a volume of the focusing fluid from the fluid bath, so as to concentrate the microbeads in the fluid bath,

2. The method according to claim 1, wherein in step (d), the fluid bath is controlled so as to be maintained at a substantially constant liquid level.

3. The method according to claim 2, wherein the substantially constant liquid level is maintained by balancing respective flow rates for the focused sirearil in step (a), the focusing stream in step (b), and the focusing fluid in step (d).

4. The method according to claim 1, wherein in step (d), the volume of the focusing fluid flows through one or more filters,

5. The method according to claim 4, wherein in step (d), the filters retain the microbeads in the fluid bath.

6. The method according to claim 4, wherein in step (d), the filters retain a substantially monodisperse set of the microbeads M the fluid bath.

7. The method according to any one of claims 4 and 5, wherein in step (d), the filters divide the microbeads into one or more collections of microbeads, with each of the collections including a respectively monodisperse set of the microbeads.

8. The method according to claim 1, wherein at least one of steps (a) and (b) is performed within an interior chamber of a flow focusing body.

9. The method according to claim 8, wherein steps (a) and (b) are both performed within the interior chamber of the flow focusing body, with an outlet portion of the flow focusing body being located below a liquid level of the fluid bath, and wherein in step (c), the focusing stream and the focused stream flow out from the outlet portion of the flow focusing body.

10. The method according to claim 9, wherein in step (b), the focused stream is focused by the focusing fluid, and wherein in step (c), the focusing stream and the focused stream flow out from the outlet portion as a single flow stream.

11. The method according to claim 10, wherein in step (c), the focusing stream substantially surrounds the focused stream in the single flow stream.

12. The method according to claim 1, further comprising a preliminary step, before step (a), of providing the fluid bath within a sealed liquid-containing cell.

13. The method according to claim 12, wherein at least one of steps (a) through (c) is performed within the liquid-containing cell.

14. The method according to any one of claims 12 and 13, wherein in the preliminary step, the liquid-containing cell additionally contains a volume of a gas at a predetermined pressure.

15. The method according to claim 14, wherein in the preliminary step, a gas pressure source pressurizes the gas, via an inlet valve, in the sealed liquid-containing cell.

16. The method according to any one of claims 14 to 15, further comprising step (c.1), after the preliminary step, of releasing a portion of the gas or the fluid bath, via a pressure safety valve, when the pressure exceeds a predetermined maximum safety pressure for the sealed liquid-containing cell.

17. The method according to any one of claims 14 to 16, wherein the gas comprises an inert gas.

18. The method according to any one of claims 14 to 17, wherein the pressure of the gas in the preliminary step is predetermined, in balance with respective flow rates for the focused stream in step (a) and the focusing stream in step (b), to maintain the fluid bath at a substantially constant liquid level.

19. The method according to any one of claims 1 to 18, further comprising step (b.1), after step (b), of maintaining the fluid bath under stirring, and wherein the microbeads are allowed to solidify in step (c),

20. The method according to claim 19, wherein in step (b.1), a stirring bar maintains the fluid bath under stirring, and wherein the stirring bar comprises an electric stirring bar or a magnetic stirring bar.

21. The method according to any one of claims 19 to 20, further comprising step (d.1), after step (d), of recovering solidified microbeads from the fluid bath.

22. The method according to any one of claims 1 to 21, further comprising step (e) of recycling at least part of the volume of the focusing fluid, flowing from the fluid bath in step (d), as at least part of the focusing stream flowing into intersection with the focused stream in step (b).

23. The method according to any one of claims 1 to 22, wherein in step (a), the medium comprises an organic solvent.

24. The method according to claim 23, wherein the organic solvent comprises chloroform, or dichloromethane.

25. The method according to any one of claims 1 to 24, wherein in step (a), the polymer is substantially hydrophobic.

26. The method according to any one of claims 1 to 25, wherein in step (a), the polymer comprises a polystyrene powder or a derivative thereof.

27. The method according to any one of claims 1 to 26, wherein in step (b), the focusing fluid comprises water.

28. The method according to any one of claims 1 to 27, wherein in step (a), the polymer solution further comprises particles dissolved and/or dispersed in the medium, and wherein in step (c), each of the microbeads binds an identifiable set of the particles.

29. The method according to claim 28, wherein in step (a), the particles comprise fluorophores.

30. The method according to claim 28, wherein in step (a), the particles comprise nanoparticles.

31. The method according to claim 30, wherein the nanoparticles comprise semiconductor nanoparticles, magnetic nanoparticles, metallic conductor nanoparticles, metal oxide nanoparticles, fluorescent nanoparticles, or phosphorescent nanoparticles.

32. The method according to claim 28, wherein in step (a), the particles comprise quantum dots.

33. The method according to claim 28, wherein in step (a), the particles comprise a combination of quantum dots and magnetic nanoparticles.

34. The method according to any one of claims 1 to 33, wherein in step (a), the polymer solution and/or suspension has a concentration of about 0.04 by weight-weight percentage (4 wt %).

35. A microbead formed according to the method in any one of claims 1 to 34.

36. A microbead according to claim 35, comprising one or more functional groups at a surface thereof, with the functional groups being adapted to operatively bind with biorecognition molecules.

37. A microbead according to claim 36, wherein the microbead, operatively bound with the biorecognition molecules, is adapted for use as a probe in a multiplexed diagnostic test for detection of one or more diseases.

38. A microbead according to claim 37, wherein the diseases include malaria, HIV, Hepatitis B, Hepatitis C, Dengue virus, or avian flu (H5SN1).

39. A microbead according to claim 36, wherein the microbead, operatively bound with the hiorecoguition molecules, is adapted for use as a probe in a multiplexed diagnostic test for detection of one or more genetic expression factors.

40. A system for forming one or more concentrated volumes of microbeads, the system comprising:

(a) a fluid bath, a focusing fluid, and a polymer solution and/or suspension comprising a polymer dissolved and/or dispersed in a medium;

(b) a flow focusing apparatus comprising;

(i) a polymer nozzle operatively delivering a focused stream of the polymer solution and/or suspension; and

(ii) a focusing nozzle operatively delivering a focusing stream of the focusing solution;

with the flow focusing apparatus operatively delivering the focused stream and the focusing stream into intersection with one another, and with the flow focusing apparatus operatively flowing the focusing stream and the focused stream into the fluid bath, so as to form the microbeads in the fluid bath; and

(c) a liquid-containing cell shaped to define an outlet port, with the liquid-containing cell operatively containing the fluid bath and operatively delivering a volume of the focusing fluid out from the fluid bath, via the outlet port, so as to concentrate the microbeads in the fluid bath.

41. The system according to claim 40, wherein operative flow rates for (i) the focused stream through the polymer nozzle, (ii) the focusing stream through the focusing nozzle, and (iii) the focusing fluid through the outlet port, respectively, are predetermined in dependent relation upon one another, so as to maintain the fluid bath at a substantially constant liquid level.

42. The system according to claim 40, wherein the liquid-containing cell comprises one or more filters on the outlet port, with the volume of the focusing fluid being operatively delivered, through the filters, out from the fluid bath.

43. The system according to claim 42, wherein the filters operatively retain the microbeads in the fluid bath.

44. The system according to claim 42, wherein the filters operatively retain a substantially monodisperse set of the microbeads in the fluid bath.

45. The system according to any one of claims 42 and 43, wherein the filters operatively divide the microbeads into one or more collections of microbeads, with each of the collections including a respectively monodisperse set of the microbeads.

46. The system according to claim 40, wherein the flow focusing apparatus further comprises a flow focusing body defining an interior chamber and an outlet portion, with the focused stream and the focusing stream being operatively delivered into intersection with one another in the chamber, and with the focusing stream and the focused stream operatively flowing out from the outlet portion of the flow focusing body.

47. The system according to claim 46, wherein the outlet portion of the flow focusing body is operatively located below a liquid level of the fluid bath.

48. The system according to any one of claims 46 and 47, wherein the focused stream is operatively focused by the focusing fluid, and wherein the focusing stream and the focused stream operatively flow out from the outlet portion as a single flow stream.

49. The system according to claim 48, wherein the focusing stream substantially surrounds the focused stream in the single flow stream.

50. The system according to claim 40, wherein the liquid-containing cell is operatively sealed relative to the outside environment.

51. The system according to claim 50, wherein the flow focusing apparatus operatively delivers the focused stream and the focusing stream, into intersection with one another, in the liquid-containing cell.

52. The system according to any one of claims 50 and 51, further comprising a volume of a gas at a predetermined pressure, operatively contained within the liquid-containing cell.

53. The system according to claim 52, further comprising a gas pressure source, wherein the liquid-containing cell is shaped to define an inlet valve, and wherein the gas pressure source operatively pressurizes the gas, via the inlet valve, in the liquid-containing cell.

54. The system according to any one of claims 52 to 53, wherein the liquid-containing cell is shaped to define a pressure safety valve, and wherein the pressure safety valve operatively releases a portion of the gas or the fluid bath, when the pressure exceeds a predetermined maximum safety pressure for the sealed liquid-containing cell.

55. The system according to claim 54, wherein the pressure safety valve is provided on, and in operative fluid relation with the outlet port of the liquid-containing cell, and wherein the pressure safety valve operatively releases a portion of the fluid bath, when the pressure exceeds the predetermined maximum safety pressure.

56. The system according to any one of claims 52 to 55, wherein the gas comprises an inert gas.

57. The system according to any one of claims 52 to 56, wherein (i) the pressure of the gas is predetermined, in balance with operative flow rates for (ii) the focused stream through the polymer nozzle and (iii) the focusing stream through, the focusing nozzle, so as to maintain the fluid bath at a substantially constant liquid level.

58. The system according to any one of claims 40 to 57, wherein the liquid-containing cell further comprises a stirring bar operatively maintaining the fluid bath under stirring, and wherein the fluid bath operatively allows the microbeads to solidify.

59. The system according to claim 58, wherein the stirring bar comprises an electric stirring bar or a magnetic stirring bar.

60. The system according to any one of claims 58 to 59, wherein the liquid-containing cell is shaped to define a sealed orifice, with the sealed orifice being selectively openable, so as to recover solidified microbeads through the orifice, from the fluid bath.

61. The system according to any one of claims 40 to 60, further comprising a conduit in fluid communication between the outlet port and the focusing nozzle, so as to operatively recycle at least part of the volume of the focusing fluid operatively delivered out from the fluid bath, via the outlet port, as at least part of the focusing stream operatively delivered by the focusing nozzle.

62. The system according to any one of claims 40 to 61, wherein the medium comprises an organic solvent.

63. The system according to claim 62, wherein the organic solvent comprises chloroform or dichloromethane.

64. The system according to any one of claims 40 to 63, wherein the polymer is substantially hydrophobic.

65. The system according to any one of claims 40 to 64, wherein the polymer comprises a polystyrene powder or a derivative thereof.

66. The system according to any one of claims 40 to 65, wherein the focusing fluid comprises water.

67. The system according to any one of claims 40 to 66, wherein the polymer solution and/or suspension further comprises particles dissolved and/or dispersed in the medium, and wherein each of the microbeads binds an identifiable set of the particles.

68. The system according to claim 67, wherein the particles comprise fluorophores.

69. The system according to claim 67, wherein the particles comprise nanoparticles.

70. The system according to claim 69, wherein the nanoparticles comprise semiconductor nanoparticles, magnetic nanoparticles, metallic conductor nanoparticles, metal oxide nanoparticles, fluorescent nanoparticles, or phosphorescent nanoparticles.

71. The system according to claim 67, wherein the particles comprise quantum dots.

72. The system according to claim 67, wherein the particles comprise a combination of quantum dots and magnetic nanoparticles.

73. The system according to any one of claims 40 to 72, wherein the polymer solution and/or suspension has a concentration of about 0.04 by weight-weight percentage (4 wt %).

74. A system for forming one or more concentrated volumes of microbeads, the system being for use with a fluid bath, a focusing fluid, and a polymer solution arid/or suspension comprising a polymer dissolved and/or dispersed in a medium, the system comprising:

(a) a flow focusing apparatus comprising;

(i) a polymer nozzle operatively delivering a focused stream of the polymer solution and/or suspension; and

(ii) a focusing nozzle operatively delivering a focusing stream of the focusing solution;

with the flow focusing apparatus operatively delivering the focused stream and the focusing stream into intersection with one another, and with the flow focusing apparatus operatively flowing the focusing stream and the focused stream into the fluid bath, so as to form the microbeads in the fluid bath; and

(b) a liquid-containing cell shaped to define an outlet port, with the liquid-containing cell operatively containing the fluid bath and operatively delivering a volume of the focusing fluid out from the fluid bath, via the outlet port, so as to concentrate the microbeads in the fluid bath.