Claims
- 1. A method of transporting material, comprising:
providing a first channel segment, a second channel segment and a third channel segment fluidly coupled at a first fluid junction; applying a pressure differential across the first channel segment to produce a first flow profile in the first channel segment, the first flow profile being dominated by non-electrokinetically driven pressure flow; and applying a voltage differential across the second channel segment to produce a second flow profile in the second channel segment, the second flow profile being dominated by electrokinetic flow.
- 2. The method of claim 1, wherein the second flow profile is substantially devoid of non-electrokinetically driven flow.
- 3. The method of claim 1, wherein the second flow profile comprises a slower flow rate than a flow rate in the first flow profile.
- 4. The method of claim 3, wherein the flow rate of the second flow profile is less than one half the flow rate of the first flow profile.
- 5. A system for transporting material, comprising:
a first channel segment having first and second ends, and a second channel segment having first and second ends, the second end of the first channel segment being fluidly coupled to the first end of the second channel segment at a first fluid junction; a flow access channel fluidly coupled to the first fluid junction; and a flow control system operably coupled to the flow access channel and the first and second channel segments, the flow control system being configured to provide a first flow profile through the first channel segment and a second flow profile through the second channel segment, the first flow profile being dominated by non-electrokinetic pressure flow, and the second flow profile being dominated by electrokinetic flow, the first and second flow profiles combining to yield substantially no flow of material into or out of the flow access channel.
- 6. The system of claim 5, wherein the first and second channel segments and flow access channel are disposed in a body structure of a microfluidic device.
- 7. The system of claim 6, wherein the flow control system comprises at least a first pressure source and at least a first voltage source.
- 8. A method of at least partially separating at least first and second species in a sample mixture, the first species having a lower electrophoretic mobility than the second species, the method comprising:
providing a device having at least first, second and third channel segments fluidly coupled at a first fluid junction; applying a pressure gradient between said first and second channel segments; and applying a voltage gradient between said second and third channel segments whereby at least a portion of the first species flows into the second channel segment while at least a portion of the second species flows into the third channel segment.
- 9. A method of at least partially separating at least first and second species in a sample mixture, the first species having a lower electrophoretic mobility than the second species, the method comprising:
providing a device having a first channel segment, a second channel segment and a third channel segment fluidly coupled at a first fluid junction; applying a voltage differential across at least the second and third channel segments; flowing the sample mixture through the first channel segment and into the first fluid junction; and applying a pressure gradient across at least the first and second channel segments such that at least a portion of said second species in the fluid junction has an electrophoretic velocity component that exceeds a pressure-driven velocity component of the portion of the second species in the fluid junction whereby said at least a portion of the second species flows into the third channel segment, while at least a portion of the first species in the fluid junction has a pressure-driven velocity component that exceeds an electrophoretic velocity component of the portion of the first species in the fluid junction such that said at least a portion of the first species flows into the second channel segment.
- 10. A method of at least partially separating at least first and second species in a sample mixture, the first species having a lower electrophoretic mobility than the second species, the method comprising:
providing a first channel segment, a second channel segment and a third channel segment fluidly coupled at a first fluid junction; applying a first pressure differential between at least the second and third channel segments; flowing the sample mixture through the first channel segment and into the fluid junction; and applying a voltage gradient between at least the first and second channel segments such that at least a portion of the second species in the fluid junction has an electrophoretic velocity component that exceeds a pressure-driven velocity component of the portion of the second species in the fluid junction whereby said at least a portion of the second species flows into the second channel segment, while at least a portion of the first species in the fluid junction has a pressure-driven velocity component that exceeds an electrophoretic velocity component of the portion of the first species in the fluid junction such that said at least a portion of the first species flows into the third channel segment.
- 11. A method of at least partially separating at least first and second species in a sample from one another, the first species having a lower electrophoretic mobility than the second species, the method comprising:
providing a first, second and third channel segment which are fluidly coupled to each other, the second channel segment having a depth which is less than a depth of the third channel segment, the second and third channel segments having the same cross-sectional area; introducing the sample into the first channel segment; and applying a first pressure differential across the first and second channel segments and first and third channel segments and at least a first voltage differential across the first and second channel segments such that an electrophoretic driving force on at least the second species is greater than a pressure driven force on the second species in at least the second channel segment whereby a portion of a total amount of the second species which is present in the first channel segment flows into the second channel segment which is greater than a portion of a total amount of the first species which is present in the first channel segment that flows into the second channel segment.
- 12. The method of claim 11, further comprising applying a second voltage differential across the first and third channel segments, wherein the first and second voltage differentials are the same.
- 13. The method of claim 11, wherein the first, second and third channel segments are disposed in a body structure of a microfluidic device.
- 14. The method of claim 11, wherein the second species has a positive charge and the first species is neutrally charged.
- 15. The method of claim 11, wherein the second species has a negative charge and the first species is neutrally charged.
- 16. The method of claim 11, wherein the first and second species are both positively charged, and the second species is more positively charged than the second species
- 17. The method of claim 12, wherein the first, second and third channel segments are fluidly coupled to first and second reservoirs, and the applying a first pressure differential and at least a first voltage differential comprises applying a pressure and voltage potential between the first and second reservoirs.
- 18. The method of claim 12, further comprising at least a fourth channel segment which is fluidly coupled to the second and third channel segments, the method further comprising applying a pressure and voltage differential across the first and fourth channel segments.
- 19. The method of claim 18, wherein the fourth channel segment has a depth along at least a portion of its length which is the same as the depth of at least one of the second and third channel segments.
- 20. The method of claim 19, wherein the depth of at least one of the second, third and fourth channel segments varies along a length of the channel segment.
- 21. The method of claim 19, wherein the depth of at least two of the second, third and fourth channel segments varies along a length of the channel segments.
- 22. The method of claim 18, wherein the second, third and fourth channel segments are oriented parallel to each other.
- 23. The method of claim 12, wherein the second and third channel segments are arranged parallel to each other.
- 24. The method of claim 11, wherein the depth of the third channel segment is at least about two times greater than the depth of the second channel segment.
- 25. The method of claim 11, wherein the depth of the third channel segment is at least about five times greater than the depth of the second channel segment.
- 26. The method of claim 11, wherein a ratio of an amount of first species flowing in the second channel segment versus an amount of first species flowing in the third channel segment is about 1 to 8.
- 27. The method of claim 11, wherein the depth of at least one of the second and third channel segments varies along a length of the channel segment.
- 28. The method of claim 11, wherein at least the third channel segment is fluidly coupled to fourth and fifth channel segments downstream of the third channel segment, the fourth channel segment having the same depth as the depth of the second channel segment and the fifth channel segment having the same depth as the depth of the third channel segment, the second, third, fourth and fifth channel segments having the same cross-sectional area, the method further comprising applying a pressure and voltage differential across the second, third, fourth and fifth channel segments such that a ratio of an amount of second species to an amount of first species flowing in the third channel segment is less than a ratio of an amount of second species to an amount of first species flowing in the fifth channel segment.
- 29. A method of at least partially concentrating at least a first charged species in a sample solution comprising:
providing a device having at least first, second and third channel segments fluidly coupled at a first fluid junction; introducing the sample containing the at least first charged species into the first channel segment; applying a pressure gradient between at least said first and second channel segments; and applying a voltage gradient between said second and third channel segments such that a greater concentration of the first species flows into the third channel segment as compared to a concentration of the first species that flows into the second channel segment.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Nos. 60/361,957 filed Mar. 5, 2002 and 60/381,306 filed May 17, 2002, each of which is incorporated herein be reference in their entirety for all purposes.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60361957 |
Mar 2002 |
US |
|
60381306 |
May 2002 |
US |