MICROFLUIDIC DEVICE FOR STORAGE AND WELL-DEFINED ARRANGEMENT OF DROPLETS

• US 20110190146A1
• Filed: 04/28/2009
• Published: 08/04/2011
• Est. Priority Date: 04/28/2008
• Status: Active Grant

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Boehm, Christian, Rowat, Amy, Koester, Sarah, Agresti, Jeremy, Weitz, David A.
• Granted Patent: US 9,664,619 B2
• Time in Patent Office: Days
• US Class Current: 506/7
• CPC Class Codes: B01L 2200/0621 Control of the sequence of chambers filled or emptied
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0819 Microarrays; Biochips
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/086 using baffles or other fixed flow obstructions
• CPC Class Codes: B01L 3/502784 specially adapted for droplet or plug flow, e.g. digital microfluidics automatic analysis using a stream of discrete samples in a tube system G01N35/08
• CPC Class Codes: B01L 7/525 with physical movement of samples between temperature zones
• CPC Class Codes: G01N 21/6452 Individual samples arranged in a regular 2D-array, e.g. multiwell plates
• CPC Class Codes: G01N 33/5008 for testing or evaluating the effect of chemical or biological compounds, e.g. drugs, cosmetics

Abstract

The present invention relates to systems and methods for the arrangement of droplets in pre-determined locations. Many applications require the collection of time- resolved data. Examples include the screening of cells based on their growth characteristics or the observation of enzymatic reactions. The present invention provides a tool and related techniques which addresses this need, and which can be used in many other situations. The invention provides, in one aspect, a tool that allows for stable storage and indexing of individual droplets. The invention can interface not only with microfluidic/microscale equipment, but with macroscopic equipment to allow for the easy injection of liquids and extraction of sample droplets, etc.

Claims

1. A method of arranging droplets at predetermined positions in an array comprising:

urging a first droplet and/or a first cell through a first constriction in a channel into a first pot.

2. The method of claim 1, further comprising:

applying a pressure differential along the channel such that the first droplet and/or the first cell is urged through a second constriction into a second pot that is downstream of the first pot.

3. The method of claim 2, further comprising:

applying a pressure differential along the channel such that a second droplet and/or a second cell is urged through the first constriction into the first pot wherein

upon removal of the applied pressure differential, the first droplet and/or the first cell is contained within the second pot and the second droplet and/or the second cell is contained within the first pot simultaneously.

4. The method of claim 1, further comprising:

forming a hole in the first pot; and

transferring the first droplet and/or the first cell in of the first pot into a well of a secondary device via the hole formed in the first pot.

5. The method of claim 4, wherein the secondary device comprises a microtiter plate.

14. The method of claim 20, wherein the property comprises fluorescence.

20. The method of claim 1 further comprising:

determining a property of the first droplet and/or the first cell in the first pot.

22. The method of claim 20, wherein the property comprises a level of expression of a gene.

23. The method of claim 20, wherein the property comprises an amount of a chemical secreted by the cell.

27. The method of claim 1, comprising urging a first droplet through the first constriction, wherein the first droplet contains a single cell.

38. The method of claim 1, further comprising:

moving a device containing the channel while maintaining the first droplet and/or first cell within the first pot.

41. The method of claim 1, comprising urging a first droplet through the first constriction, wherein the first droplet contains a chemical reaction.

43. The method of claim 1,

comprising urging a first droplet through the first constriction, wherein the first droplet is one of a plurality of droplets, and wherein:

the channel comprises a plurality of pots, and

at least about 1% of the plurality of droplets are contained within the pots.

44. The method of claim 43, wherein the at least about 1% of the plurality of droplets are loaded into pots at a rate of at least about 10 droplets per second.

6-13. -13. (canceled)

15-19. -19. (canceled)

21. (canceled)

24-26. -26. (canceled)

28-37. -37. (canceled)

39-40. -40. (canceled)

42. (canceled)

45-51. -51. (canceled)

52. A method of arranging droplets comprising:

applying a pressure differential along a channel comprising a series of pots substantially each containing at least one droplet, said series of pots connected via a series of constrictions arranged such that each pot is in direct fluid communication with no more than two other pots and each pot is connected to exactly two constrictions, and

ejecting the droplets from the an exit of the channel in the order in which they the droplets were placed arranged in the pots prior to being ejected from the exit.

53. The method of claim 52, further comprising:

injecting a third fluid after each droplet exits the channel such that the third fluid maintains consistent spacing between the droplets that exit the channel.

54-55. -55. (canceled)

56. A device for arranging droplets comprising:

a microfluidic channel comprising a series of pots connected via a series of constrictions arranged such that each pot is in direct fluid communication with no more than two other pots and each pot is connected to exactly two constrictions.

57. The device of claim 56, further comprising a plurality of channels each comprising a series of pots connected via a series of constrictions arranged such that each pot is in direct fluid communication with no more than two other pots and each pot is connected to exactly two constrictions.

62. The device of claim 57, wherein the volume of at least one of the pots is less than about 10 nanoliters.

64. The device of claim 56, further comprising:

a gas-permeable membrane that separates the contents of at least some of the pots from ambient atmosphere.

58-61. -61. (canceled)

63. (canceled)

65-71. -71. (canceled)