Metering doses of sample liquids

• US 20050181519A1
• Filed: 08/05/2004
• Published: 08/18/2005
• Est. Priority Date: 02/17/2004
• Status: Active Grant

• Current Assignee: Molecular BioProducts Incorporated (Perspecta, Inc.)
• Original Assignee: Nascent BioSciences Inc. (Thermo Fisher Scientific Incorporated)
• Inventors: Karg, Jeffrey A., Kroncke, Douglas W.
• Granted Patent: US 7,592,185 B2
• Time in Patent Office: Days
• US Class Current: 436/180
• CPC Class Codes: B01F 23/451 by injecting one liquid into another
• CPC Class Codes: B01F 23/483 using water for diluting a liquid ingredient, obtaining a predetermined concentration or making an aqueous solution of a concentrate
• CPC Class Codes: B01F 35/882 using measuring chambers, e.g. volumetric pumps, for feeding the substances
• CPC Class Codes: B01L 2300/06 Auxiliary integrated devices, integrated components
• CPC Class Codes: B01L 2300/0858 Side walls
• CPC Class Codes: B01L 3/021 Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
• CPC Class Codes: B01L 3/0275 Interchangeable or disposable dispensing tips
• CPC Class Codes: B01L 3/0293 for liquids
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 2035/1032 Dilution or aliquotting
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A method of metering and mixing a dose of a sample liquid with a diluent liquid includes introducing a sample liquid into a channel defined in a housing. The housing defines a pocket open to the channel and sized to both collect a metered dose of the sample liquid, and to retain the collected dose by capillary force when the channel is emptied. The sample liquid is then removed from the channel under conditions that enable retention of the collected, metered dose of the sample liquid in the pocket. Following a cleaning step, a volume of diluent liquid is introduced into the channel to induce diffusion and mixing of the diluent liquid with the dose of sample liquid to form a mixture.

Claims

1. A method of metering and mixing a dose of a sample liquid with a diluent liquid, the method comprising;

introducing a sample liquid into a channel defined in a housing, the housing defining a pocket open to the channel and sized to collect a metered dose of the sample liquid, and to retain the collected dose by capillary force when the channel is emptied;

removing sample liquid from the channel under conditions that enable retention of the collected, metered dose of the sample liquid in the pocket; and

then

introducing a volume of a diluent liquid into the channel to induce diffusion and mixing of the diluent liquid with the dose of sample liquid to form a mixture.

2. The method according to claim 1 further comprising, after removing the sample liquid from the channel and before introducing the volume of diluent liquid,

introducing a cleaning liquid into the channel below the pocket;

and then

removing the cleaning liquid from the channel to flush any residual sample liquid from surfaces of the channel below the pocket.

3. The method according to claim 1 wherein the housing comprises a tube defining the channel therewithin.

4. The method according to claim 3 wherein the tube has an open lower end through which the sample liquid is introduced by drawing the liquid into the tube.

5. The method according to claim 4 wherein the channel is narrower at the lower end of the tube than in an upper section of the tube.

6. The method according to claim 4 wherein the pocket is disposed in a portion of the channel wider than the channel at the open end of the tube.

7. The method according to claim 3 wherein the pocket comprises an upwardly extending notch defined in an interior wall of the tube.

8. The method according to claim 3 wherein a surface of the tube defining a lower extent of the pocket is substantially perpendicular to a longitudinal axis of the tube.

9. The method according to claim 3 wherein the pocket is elongated and parallel to a longitudinal axis of the tube.

10. The method according to claim 9 wherein the pocket has a length of between about 0.01 and about 1 inch (0.25 and 25 millimeters), as measured parallel to the longitudinal axis of the tube.

11. The method according to claim 9 wherein the pocket has a width of between about 0.001 and about 0.04 inch (0.025 and 1.02 millimeters).

12. The method according to claim 3 wherein the pocket has a depth of between about 0.001 and about 0.100 inch (0.025 and 2.54 millimeters), measured along a radial line extending from the longitudinal axis of the tube.

13. The method according to claim 1 wherein the housing comprises a laminated plate defining the liquid channel, the pocket and an input orifice in fluid contact with the channel.

14. The method according to claim 13 wherein the sample liquid is introduced and removed from the channel pneumatically.

15. The method according to claim 1 further comprising dispensing a metered volume of the mixture into a destination well.

16. The method according to claim 15 wherein dispensing the metered volume comprises pneumatically propelling the mixture from the housing.

17. The method according to claim 15 wherein the mixture is propelled from the housing by pressurized gas.

18. The method according to claim 1 wherein the pocket is sized to collect a metered dose of sample liquid of between about 1 nanoliter and about 10 microliters in volume.

19. The method according to claim 18 wherein the pocket is sized to collect a metered dose of sample liquid of between about 5 nanoliters and about 10 microliters in volume.

20. The method of claim 1 wherein the volume of diluent liquid introduced into the channel is in the range of between about 1 nanoliter and about 1 milliliter.

21. The method according to claim 1 wherein the housing defines a plurality of said pockets spaced from one another.

22. The method according to claim 1 wherein the pocket is formed from a method selected from the group consisting of molding, machining, welding, casting, swaging, cold forming and coating.

23. The method according to claim 1 wherein the pocket is formed of a material secured to a material forming an inner surface of the housing.

24. The method according to claim 1 wherein the pocket is defined in a protrusion extending into the channel.

25. The method according to claim 1 wherein the diluent liquid is moved reciprocally across the pocket multiple times, to induce mixing with the dose of sample liquid.

26. A method of metering and mixing a dose of a sample liquid with a diluent liquid, the method comprising;

drawing a sample liquid into a pipette defining an internal cavity and having an interior wall defining a pocket sized to collect a metered dose of the sample liquid;

expelling the sample liquid from the pipette under conditions that enable retaining the collected, metered dose of the sample in the pocket by capillary force; and

then

drawing a volume of a diluent liquid into the pipette a sufficient distance to contact the retained dose of sample liquid, to induce diffusion and mixing of the diluent liquid with the dose of sample liquid.

27. The method according to claim 26 further comprising, after expelling the sample liquid from the pipette and before drawing the volume of diluent liquid into the pipette,

drawing a cleaning liquid into the pipette below the pocket;

and then

expelling the cleaning liquid from the pipette to flush any residual sample liquid from surfaces of the interior wall below the pocket.

28. The method according to claim 26 wherein the pipette is formed from a synthetic resin.

29. The method according to claim 26 further comprising dispensing a metered volume of the mixture into a destination well.

30. The method according to claim 29 wherein dispensing the metered volume comprises pneumatically propelling the mixture from the pipette.

31. The method according to claim 29 wherein the pipette further defines a capillary hole between an outer surface of the pipette and the internal cavity.

32. The method according to claim 31 wherein the mixture is propelled from the pipette by forcing a pressurized gas into the internal cavity through the capillary hole.

33. The method according to claim 26 wherein the pocket is sized to collect a metered dose of sample liquid of between about 1 nanoliter and about 10 microliters in volume.

34. The method according to claim 33 wherein the pocket is sized to collect a metered dose of sample liquid of between about 5 nanoliters and about 10 microliters in volume.

35. The method according to claim 26 wherein the internal cavity is narrower at a lower open end of the pipette than in an upper section of the pipette.

36. The method according to claim 35 wherein the pocket is disposed in a portion of the internal cavity wider than the internal cavity at the open end of the pipette.

37. The method according to claim 26 wherein the pocket comprises an upwardly extending notch defined in an interior wall of the pipette.

38. The method according to claim 26 wherein a surface of the pipette defining a lower extent of the pocket is substantially perpendicular to a longitudinal axis of the pipette.

39. The method according to claim 26 wherein the pocket is elongated and parallel to a longitudinal axis of the pipette.

40. The method according to claim 39 wherein the pocket has a length of between about 0.01 and about 1 inch (0.25 and 25 millimeters), as measured parallel to the longitudinal axis of the pipette.

41. The method according to claim 39 wherein the pocket has a width of between about 0.001 and about 0.04 inch (0.025 and 1.02 millimeters).

42. The method according to claim 26 wherein the pocket has a depth of between about 0.001 and about 0.100 inch (0.025 and 2.54 millimeters), measured along a radial line extending from the longitudinal axis of the pipette.

43. The method of claim 26 wherein the volume of diluent liquid introduced into the internal cavity is in the range of between about 1 nanoliter and about 500 microliters.

44. The method according to claim 26 wherein the pipette defines a plurality of said pockets spaced apart from one another.

45. The method according to claim 26 wherein the pocket is formed from a method selected from the group consisting of molding, machining, welding, casting, swaging, cold forming and coating.

46. The method according to claim 26 wherein the pocket is defined in a protrusion extending into the internal cavity.

47. The method according to claim 26 wherein the diluent liquid is moved reciprocally across the pocket multiple times, to induce mixing with the dose of sample liquid.

48. A method of metering and mixing a plurality of doses of a sample liquid with a diluent liquid, the method comprising;

providing an array of pipettes, each pipette defining an internal cavity and having an interior wall defining a pocket sized to collect a metered dose of a sample liquid;

drawing the sample liquid into the pipettes;

expelling the sample liquid from the pipettes under conditions that enable retaining the collected, metered doses of the sample in the pockets by capillary force; and

then

drawing a diluent liquid into the pipettes a sufficient distance to contact the retained doses of sample liquid, to induce diffusion and mixing of the diluent liquid with the doses of sample liquid.

49. The method according to claim 48 further comprising, after expelling the sample liquid from the pipettes and before drawing the diluent liquid into the pipettes, drawing a cleaning liquid into the pipettes below the pockets;

and then expelling the cleaning liquid from the pipettes to flush any residual sample liquid from surfaces of the interior wall below the pocket.

50. The method according to claim 48 wherein the pipettes are formed from a synthetic resin.

51. The method according to claim 48 further comprising dispensing from each pipette a metered volume of the mixture into a destination well.

52. The method according to claim 51 wherein dispensing the metered volume comprises pneumatically propelling the mixture from the pipettes.

53. The method according to claim 52 wherein each pipette further defines a capillary hole between an outer surface of the pipette and the internal cavity.

54. The method according to claim 53 wherein the mixture is propelled from the pipette by forcing a pressurized gas into the internal cavity through the capillary hole.

55. The method according to claim 48 wherein the pocket is sized to collect a metered dose of sample liquid of between about 1 nanoliter and about 10 microliters in volume.

56. The method according to claim 55 wherein the pocket is sized to collect a metered dose of sample liquid of between about 5 nanoliters and about 10 microliters in volume.

57. The method according to claim 48 wherein the internal cavity is narrower at a lower open end of the pipette than in an upper section of the pipette.

58. The method according to claim 57 wherein the pocket is disposed in a portion of the internal cavity wider than the internal cavity at the open end of the pipette.

59. The method according to claim 48 wherein the pocket comprises an upwardly extending notch defined in an interior wall of the pipette.

60. The method according to claim 48 wherein a surface of the pipette defining a lower extent of the pocket is substantially perpendicular to a longitudinal axis of the pipette.

61. The method according to claim 48 wherein the pocket is elongated and parallel to a longitudinal axis of the pipette.

62. The method of claim 48 wherein the volume of diluent liquid introduced into the internal cavity is in the range of between about 1 nanoliter and about 500 microliters.

63. The method according to claim 48 wherein the pipette defines a plurality of said pockets spaced apart from one another.

64. The method according to claim 48 further comprising dispensing a metered volume of the mixture into an array of liquid-receiving units.

65. The method of claim 64 wherein the array of pipettes is aligned directly above the array of liquid-receiving units.

66. The method according to claim 64 wherein the array of liquid-receiving units is a multi-well container.

67. The method according to claim 66 wherein the multi-well container is selected from the group consisting of a 96-well microtiter plate, a 384-well microtiter plate, and 1536-well microtiter plate.

68. The method according to claim 48 further comprising dispensing a metered volume of the mixture onto a slide.

69. The method according to claim 48 further comprising dispensing a metered volume of the mixture onto an electronic assay reading device.

70. A pipette comprising:

an elongated body having an outer surface and defining an internal cavity open at a lower end of the body;

the body defining an opening in an upper portion of the body, through which air can be drawn from the cavity to draw liquids into the cavity through the lower end of the body;

wherein the body has an interior wall defining a pocket open to the internal cavity, the pocket sized to collect and retain a metered dose of a liquid drawn into the cavity as the cavity is otherwise evacuated.

71. The pipette according to claim 70 wherein the body is formed from a synthetic resin.

72. The pipette according to claim 70 wherein the body further defines a capillary hole extending from the outer surface to the internal cavity.

73. The pipette according to claim 70 wherein the pocket is sized to collect a metered dose of sample liquid between about 1 nanoliter and about 10 microliters in volume.

74. The pipette according to claim 73 wherein the pocket is sized to collect a metered dose of sample liquid between about 5 nanoliters and about 10 microliters in volume.

75. The pipette according to claim 70 wherein the pocket is disposed in a portion of the internal cavity wider that the cavity at the open end of the body.

76. The pipette according to claim 70 wherein the pocket comprises an upwardly extending notch defined in the interior wall of the body.

77. The pipette according to claim 70 wherein the surface of the pipette defining the lower extent of the pocket is substantially perpendicular to a longitudinal axis of the body.

78. The pipette according to claim 70 wherein the pocket is elongated and parallel to a longitudinal axis of the body.

79. The pipette according to claim 78 wherein the pocket has a length of between about 0.01 and about 1 inch (0.25 and 25 millimeters), as measured parallel to the longitudinal axis of the pipette.

80. The pipette according to claim 78 wherein the pocket has a width of between about 0.001 and about 0.04 inch (0.025 and 1.02 millimeters).

81. The pipette according to claim 70 wherein the pocket has a depth of between about 0.001 and about 0.100 inch (0.025 and 2.54 millimeters), measured along a radial line extending from the longitudinal axis of the pipette.

82. The pipette according to claim 70 wherein the body defines a plurality of said pockets spaced apart from one another.

83. The pipette according to claim 70 wherein the pocket is defined in a protrusion extending into the internal cavity.