One-directional microball valve for a microfluidic device

1. A system comprising:

a rotatable platen;

a microfluidic device disposed on the rotatable platen, the microfluidic device comprising a substrate having a thickness;

at least one microfluidic pathway formed in the substrate, the microfluidic pathway including a passageway, the passageway including an entrance opening having a first minimum dimension, and an exit opening having a second minimum dimension that is greater than the first minimum dimension, the passageway further including a valve seat surface situated between the entrance opening and the exit opening; and

a ball element in the passageway between the entrance opening and the exit opening, the ball element adapted to unseat from the valve seat surface upon flow of a fluid from the entrance opening toward the exit opening upon rotation of the rotatable platen.

2. The system of claim 1 , wherein the ball element is captured in the passageway.

3. The system of claim 1 , wherein the ball element has an outer peripherial surface that is complementary to the valve seat surface.

4. The system of claim 1 , wherein the pathway further comprises at least one microfluidic feature arranged downstream and in fluid communication with the exit opening.

5. The system of claim 1 , further comprising a feature downstream of the exit opening, and a barrier formed between the downstream feature and the exit opening; and

wherein the ball element has a minimum dimension and the pathway including the barrier has a minimum dimension that is less than the minimum dimension of the ball element.

6. The system of claim 1 , further comprising at least one microfluidic feature arranged upstream and in fluid communication with the entrance opening.

7. The system of claim 1 , wherein the substrate includes a top surface and a bottom surface, the bottom surface is at least substantially parallel to the top surface, the passageway includes a longitudal axis, and the longitudal axis of the passageway is at least substantially perpendicular to the top and bottom surfaces.

8. The system of claim 1 , wherein the passageway includes a through hole through the substrate.

9. The system of claim 8 , wherein the through hole is a tapered through hole.

10. The system of claim 1 , wherein the microfluidic device further includes a cover, the substrate includes a surface, the surface is in contact with the cover, and the pathway further includes at least one microfluidic feature formed in the surface of the substrate and covered by the cover.

11. The system of claim 10 , wherein the microfluidic feature includes at least one of a channel, a chamber, a reservoir, a port, a via, a recess, a divider, a flow splitter, a column, a purification column, and a combination thereof.

12. The system of claim 10 , wherein the microfluidic feature contains reagents for polymerase chain reaction.

13. The system of claim 1 , wherein the valve seat surface is at least substantially circular.

14. The system of claim 1 , wherein the ball element comprises a polycarbonate material.

15. The system of claim 1 , wherein the passageway has a hollow cylindrical shape and the entrance opening is defined by a shoulder.

16. A system comprising:

a heater;

a microfluidic device comprising a substrate having a thickness, at least one microfluidic pathway formed in the substrate, the microfluidic pathway including a passageway, the passageway including an entrance opening having a first minimum dimension, and an exit opening having a second minimum dimension that is greater than the first minimum dimension, the passageway further including a valve seat surface situated between the entrance opening and the exit opening, and a ball element in the passageway between the entrance opening and the exit opening, the ball element adapted to at least one of seat against and unseat from the valve seat surface upon a change of pressure of a fluid within the passageway resulting from heating of the fluid by the heater.

17. The system of claim 16 , wherein the ball element is captured in the passageway.

18. The system of claim 16 , wherein the ball element has an outer peripherial surface that is complementary to the valve seat surface.

19. The system of claim 16 , wherein the pathway further comprises at least one microfluidic feature arranged downstream and in fluid communication with the exit opening.

20. The system of claim 16 , further comprising a feature downstream of the exit opening, and a barrier formed between the downstream feature and the exit opening; and

wherein the ball element has a minimum dimension and the pathway including the barrier has a minimum dimension that is less than the minimum dimension of the ball element.

21. The system of claim 16 , further comprising at least one microfluidic feature arranged upstream and in fluid communication with the entrance opening.

22. The system of claim 16 , wherein the substrate includes a top surface and a bottom surface, the bottom surface is at least substantially parallel to the top surface, the passageway includes a longitudal axis, and the longitudal axis of the passageway is at least substantially perpendicular to the top and bottom surfaces.

23. The system of claim 16 , wherein the passageway includes a through hole through the substrate.

24. The system of claim 23 , wherein the through hole is a tapered through hole.

25. The system of claim 16 , wherein the microfluidic device further includes a cover, the substrate includes a surface, the surface is in contact with the cover, and the pathway further includes at least one microfluidic feature formed in the surface of the substrate and covered by the cover.

26. The system of claim 25 , wherein the microfluidic feature includes at least one of a channel, a chamber, a reservoir, a port, a via, a recess, a divider, a flow splitter, a column, a purification column, and a combination thereof.

27. The system of claim 25 , wherein the microfluidic feature contains reagents for polymerase chain reaction.

28. The system of claim 16 , wherein the valve seat surface is at least substantially circular.

29. The system of claim 16 , wherein the ball element comprises a polycarbonate material.

30. The system of claim 16 , wherein the passageway has a hollow cylindrical shape and the entrance opening is defined by a shoulder.