MICROFLUIDIC SYSTEMS AND METHODS

• US 20100234674A1
• Filed: 01/05/2010
• Published: 09/16/2010
• Est. Priority Date: 01/05/2009
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois, Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Wheeler, Matthew B., Kim, Dongshin, Beebe, David J.
• Granted Patent: US 9,157,550 B2
• Time in Patent Office: Days
• US Class Current: 600/35
• CPC Class Codes: A61B 17/425 for reproduction or fertilisation specially adapted for use with animals A61D19/00
• CPC Class Codes: B01L 2300/0829 Multi-well plates; Microtitration plates
• CPC Class Codes: B01L 3/5085 for multiple samples, e.g. microtitration plates
• CPC Class Codes: C12M 21/06 for in vitro fertilization
• CPC Class Codes: C12M 23/16 Microfluidic devices; Capillary tubes integrated microfluidic structures B01L3/5027; microreactors B01J19/0093
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0017 Capillary or surface tension valves, e.g. using electro-wetting or electro-capillarity effects
• CPC Class Codes: F16K 99/0028 Valves having multiple inlets or outlets
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/87249 Multiple inlet with multiple outlet

Abstract

Microfluidic systems and methods. A microfluidic device for in vitro fertilization comprises a substrate and a plurality of microchannels disposed in the substrate, including an inlet of at least two of the plurality of microchannels arranged on the substrate to align with a fluid-handling device. Another microfluidic system for assaying a plurality of cells comprises a substrate and a plurality of microfluidic channels comprising a source channel, a sink channel, and a cell chamber. An insert for a microfluidic system comprises a substrate configured to be inserted into a dish and a plurality of microscale wells disposed in the substrate. A microfluidic channel comprises a substrate and at least one microchannel having an open inlet, an open outlet, a channel, and an opening in the substrate disposed over a portion of the channel. A device for providing an amount of fluid for a fluidic system comprises a main reservoir, an aspiration well, tubing coupling the reservoirs, and a seal closing the main reservoir. Air tubing having a hydrophobic end extends into the at least one aspiration well.

Claims

10. A microfluidic system for assaying a plurality of cells, the microfluidic system comprising:

a substrate; and

a plurality of microfluidic channels arranged in the substrate, each of said plurality of microfluidic channels comprising;

a source channel at an end of said microfluidic channel and a sink channel at an opposing end, said source channel having an inlet and an outlet;

a cell chamber disposed within said microfluidic channel between said source channel and said sink channel;

a cell inlet in fluid communication with said cell chamber; and

a fluidic resistance disposed between said cell chamber and one of said sink channel and said source channel.

1. A microfluidic device for in vitro fertilization, comprising:

a substrate;

a plurality of microchannels disposed in said substrate, each of the microchannels including an inlet at an end for receiving a cell and an outlet at an opposing end;

wherein each of the microchannels further comprises a restriction disposed near the outlet;

wherein an inlet of at least two of said plurality of microchannels are arranged on the substrate to align with a fluid-handling device.

2. The microfluidic device of claim 1, wherein the restriction is sized to prevent an embryo from passing therethrough but to allow fluid to flow therethrough.

3. The microfluidic device of claim 1, wherein said plurality of microchannels are arranged in at least one of a one-dimensional array and a two-dimensional array within the substrate.

4. The microfluidic device of claim 3, wherein the substrate comprises PDMS, and wherein said plurality of microchannels are formed within the substrate using microfabrication.

5. The microfluidic device of claim 1, wherein at least one of said plurality of microchannels is generally spiral-shaped.

6. The microfluidic device of claim 1, wherein said substrate is coupled with a base;

wherein at least one of the plurality of microchannels is at least partially defined by a surface of the base.

7. The microfluidic device of claim 1 wherein the fluid-handling device comprises an automatic fluid-handling device.

8. The microfluidic device of claim 7, wherein the automatic fluid-handling device comprises at least one of an automatic pipette and a flow cytometer.

9. A method for in vitro fertilization using the microfluidic device of claim 1, the method comprising:

introducing an oocyte to each of the inlets at the at least two of said plurality of microchannels using the fluid-handling device, wherein the oocyte moves through a liquid media in the microchannels and reaches the restriction;

after a period of time, introducing a sperm into each of the inlets at the at least two of said plurality of microchannels.

11. The microfluidic system of claim 10, wherein said the substrate comprises PDMS, and wherein said plurality of microfluidic channels are formed within the substrate by microfabrication.

12. The microfluidic system of claim 1, wherein said substrate is coupled with a base:

wherein at least one of the plurality of microfluidic channels is at least partially defined by a surface of the base.

13. The microfluidic system of claim 10, wherein said source channel and said sink channel for each of the plurality of microfluidic channels are disposed along said substrate to align with a fluid handling robot.

14. The microfluidic system of claim 10

wherein said fluidic resistance is disposed between said cell chamber and said sink channel;

and

wherein a narrow portion of the microfluidic channel is disposed between said source channel and said cell chamber.

15. The microfluidic system of claim 10

wherein said fluidic resistance is disposed between said cell chamber and said source channel;

and

wherein a narrow portion of the microfluidic channel is disposed between said sink channel and said cell chamber.

16. The microfluidic system of claim 10, wherein said cell chamber is at least one of pyramidal and square shape.

17. The microfluidic system of claim 10, wherein said fluidic resistance comprises at least one protrusion formed in said microfluidic channel.

18. A method for assaying using the microfluidic system of claim 10, the method comprising:

loading at least one cell into said cell chamber via said cell inlet;

introducing an attractant into one of said source channel and said sink channel;

introducing a medium into the other of said source channel and said sink channel;

wherein a concentration gradient of the attractant in the medium is developed within said cell chamber due to diffusion.

19. The method of claim 18, wherein the concentration gradient has a generally radial shape.

20. The method of claim 18, further comprising:

assessing movement of the at least one cell along the concentration gradient.

21. The method of claim 18, wherein the attractant comprises a chemoattractant.

22. An insert for a microfluidic system comprising:

a substrate;

a plurality of microscale wells disposed in said substrate, wherein each of said plurality of microscale wells has a predetermined size;

wherein said plurality of microscale wells are uniformly distributed in said substrate;

wherein each of said plurality of microscale wells are fabricated in said substrate using at least one of soft lithography and injection molding;

wherein said substrate is configured to be inserted into a dish.

23. The microfluidic system of claim 21, wherein the predetermined size is determined according to a cell of a target species.

24. The microfluidic system of claim 21, wherein said substrate includes a lower surface;

and

wherein an adhesive is provided on the lower surface.

25. The microfluidic system of claim 21, further comprising;

a dish having a surface;

wherein a lower surface of said substrate is coupled to the surface of the dish.

26. The microfluidic system of claim 25, wherein said substrate is adhered to said dish.

27. The microfluidic system of claim 25, wherein said substrate is mounted to said dish.

28. The microfluidic system of claim 25, wherein said substrate is fitted into said dish.

22-1. The microfluidic system of claim 21, further comprising:

at least one channel disposed in said substrate and fluidly coupling at least two of said plurality of microscale wells.

29. A method of fabricating a microfluidic system comprising:

providing a substrate;

fabricating, using soft lithography, an array of microscale wells in said substrate, wherein fabrication of each of said microscale wells is controlled to have a predetermined size, depth, and distance therebetween;

inserting said substrate into a dish; and

attaching said substrate to the dish.

30. A microfluidic channel comprising:

a substrate;

at least one microchannel disposed in said substrate, wherein each of said at least one microchannel comprises;

an open inlet at one end;

an open outlet at an opposing end;

a channel within said substrate and disposed between said inlet and said outlet; and

an opening in said substrate disposed over a portion of said channel to expose an open portion of said channel.

31. The microfluidic channel of claim 30, wherein said substrate comprises PDMS.

32. The microfluidic channel of claim 30, wherein said substrate comprises at least two layers bonded together.

33. The microfluidic channel of claim 30, wherein said at least one microchannel further comprises a first portion leading from said inlet to the open portion and a second portion leading from the open portion to said open outlet.

34. The microfluidic system of claim 33, wherein a space is defined under the opening, said space extending below the first portion and the second portion for accommodating a culture.

35. A fluid flow method using the microfluidic system of claim 30, the method comprising:

inducing flow from said inlet to said outlet via passive pumping, wherein a liquid level of a window provided by said opening is maintained constantly; and

loading at least one cell into said opening.

36. For a fluidic system, a device for providing an amount of fluid comprising:

a first reservoir providing a main reservoir;

at least one second reservoir separate from said first reservoir, said at least one second reservoir providing an aspiration well;

a siphon tubing coupling said first reservoir and said at least one second reservoir;

a seal closing said first reservoir;

an air tubing extending through a portion of said seal, said air tubing being coupled to said at least one second reservoir and having an end extending into said at least one second reservoir; and

wherein the end of said air tubing is hydrophobic.

37. The device of claim 36, wherein said seal comprises a cap;

and

wherein said air tubing extends through an opening of said cap.

38. The device of claim 36, wherein the end of said second reservoir has a self-assembled monolayer (SAM) formed thereon.

39. The device of claim 36, wherein said first reservoir is partially filled with a fluid, whereby an air gap is provided between the fluid and said seal;

and

wherein another end of said air tubing is exposed to the air gap.

40. The device of claim 36, wherein said first reservoir comprises a vial.

41. The device of claim 36, wherein said at least one second reservoir comprises at least one well.

42. A method of dispensing a fluid comprising:

providing a first reservoir providing a main reservoir, at least one second reservoir separate from said first reservoir and providing an aspiration well, a siphon tubing coupling said first reservoir and said at least one second reservoir, a seal closing said first reservoir, and an air tubing extending through a portion of said seal, wherein said air tubing is coupled to said at least one second reservoir and has an end extending into said at least one second, reservoir, and wherein the end of said air tubing is hydrophobic;

filling a portion of the first reservoir with a liquid;

closing the seal to close the first reservoir, wherein an opposite end of the air tubing is disposed through an opening of the seal; and

inducing a negative pressure in the at least one second reservoir, wherein the liquid is dispensed from said first reservoir to said at least one second reservoir via the siphon tubing until the dispensed liquid reaches the hydrophobic end of the air tubing.