MICROFABRICATED STRUCTURES FOR FACILITATING FLUID INTRODUCTION INTO MICROFLUIDIC DEVICES

• US 20070102295A1
• Filed: 12/29/2006
• Published: 05/10/2007
• Est. Priority Date: 06/06/1997
• Status: Active Grant

• Current Assignee: Calvin Chow, J Parce, Steven Sundberg
• Original Assignee: Calvin Chow, J Parce, Steven Sundberg
• Inventors: Chow, Calvin, Sundberg, Steven, Parce, J.
• Granted Patent: US 7,364,915 B2
• Time in Patent Office: Days
• US Class Current: 204/451
• CPC Class Codes: B01J 19/0093 Microreactors, e.g. miniaturised or microfabricated reactors laboratory containers with capillary fluid transport in microfabricated channels or chambers B01L3/5027
• CPC Class Codes: B01J 2219/00783 Laminate assemblies, i.e. the reactor comprising a stack of plates
• CPC Class Codes: B01J 2219/00826 Quartz
• CPC Class Codes: B01J 2219/00831 Glass
• CPC Class Codes: B01J 2219/00833 Plastic
• CPC Class Codes: B01J 2219/00853 Employing electrode arrangements
• CPC Class Codes: B01J 2219/00891 Feeding or evacuation
• CPC Class Codes: B01J 2219/00909 using filters
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2300/0681 Filter
• 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 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0418 electro-osmotic flow [EOF]
• CPC Class Codes: B01L 2400/0421 electrophoretic flow
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 3/0244 using pins
• CPC Class Codes: B01L 3/0262 using touch-off at substrate or container
• CPC Class Codes: B01L 3/5025 : for parallel transport of multiple samples
• CPC Class Codes: B01L 3/50255 : Multi-well filtration
• 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: B01L 3/502715 : characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• CPC Class Codes: B01L 3/502723 : characterised by venting arrangements
• CPC Class Codes: B01L 3/50273 : characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502753 : characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation separation in general B01D; microapparatus for analysis using electrophoresis G01N27/44791; sample preparation G01N1/28
• CPC Class Codes: G01N 2035/00237 : Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 2035/1037 : Using surface tension, e.g. pins or wires
• CPC Class Codes: G01N 27/44743 : Introducing samples
• CPC Class Codes: G01N 27/44791 : Microapparatus sample containers with integrated microfluidic structures B01L3/5027
• CPC Class Codes: Y10T 436/25125 : Digestion or removing interfering materials
• CPC Class Codes: Y10T 436/25375 : Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]
• CPC Class Codes: Y10T 436/2575 : Volumetric liquid transfer

Abstract

Fluid introduction is facilitated through the use of a port which extends entirely through a microfluidic substrate. Capillary forces can be used to retain the fluid within the port, and a series of samples or other fluids may be introduced through a single port by sequentially blowing the fluid out through the substrate and replacing the removed fluid with an alternate fluid, or by displacing the fluid in part with additional fluid. In another aspect, microfluidic substrates have channels which varying in cross-sectional dimension so that capillary action spreads a fluid only within a limited portion of the channel network. In yet another aspect, the introduction ports may include a multiplicity of very small channels leading from the port to a fluid channel, so as to filter out particles or other contaminants which might otherwise block the channel at the junction between the channel and the introduction port.

Claims

1. A method for evacuating a first fluid from a microfluidic channel, the method comprising:

providing a substrate having a first surface and a second surface, said substrate further having a plurality of through-hole ports extending through said substrate, each of said plurality of through-hole ports having a first open end at said first surface and a second open end at said second surface;

retaining a first fluid within said plurality of through-hole ports; and

evacuating said first fluid from at least one of said plurality of through-hole ports.

2. The method according to claim 1 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises applying a differential pressure to said at least one of said plurality of through-hole ports to overcome forces associated with said step of retaining said first fluid.

3. The method according to claim 2 wherein said applying a differential pressure comprises applying a vacuum at said second open end of said substrate.

4. The method according to claim 2 wherein said applying a differential pressure comprises applying a pressure at said first open end of said substrate.

5. The method according to claim 1 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises introducing a second fluid within said at least one of said plurality of through-hole ports to force said first fluid therefrom.

6. The method according to claim 1 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises electrokinetically ejecting said first fluid from said at least one of said plurality of through-hole ports.

7. The method according to claim 1 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises inserting a member within said at least one of said plurality of though-hole ports to facilitate flow of said first fluid.

8. The method according to claim 7 wherein said inserting a member comprises inserting a pin member.

9. The method according to claim 7 wherein said inserting a member comprises inserting a hydrophilic pin member.

10. A method for evacuating a first fluid from a microfluidic channel, the method comprising:

providing a substrate having a first surface and a second surface, said substrate further having a plurality of through-hole ports extending through said substrate, each of said plurality of through-hole ports having a first open end at said first surface and a second open end at said second surface;

retaining a first fluid within said plurality of through-hole ports through at least in part capillary action; and

evacuating said first fluid from at least one of said plurality of through-hole ports.

11. The method according to claim 10 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises applying a differential pressure to said at least one of said plurality of through-hole ports to overcome forces associated with said capillary action.

12. The method according to claim 11 wherein said applying a differential pressure comprises applying a vacuum at said second open end of said substrate, said vacuum being greater than a force associated with said capillary action.

13. The method according to claim 11 wherein said applying a differential pressure comprises applying a pressure at said first open end of said substrate.

14. The method according to claim 10 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises introducing a second fluid within said at least one of said plurality of through-hole ports to force said first fluid therefrom.

15. The method according to claim 10 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises electrokinetically ejecting said first fluid from said at least one of said plurality of through-hole ports.

16. The method according to claim 10 wherein said evacuating said first fluid from said at least one of said plurality of through-hole ports comprises inserting a member within said at least one of said plurality of though-hole ports to facilitate flow of said first fluid.

17. The method according to claim 16 wherein said inserting a member comprises inserting a pin member.

18. The method according to claim 16 wherein said inserting a member comprises inserting a hydrophilic pin member.

19. A method for evacuating a first fluid from a microfluidic channel, the method comprising:

providing a substrate having a first surface and a second surface, said substrate further having a plurality of through-hole ports extending through said substrate, each of said plurality of through-hole ports having a first open end at said first surface and a second open end at said second surface;

retaining a first fluid within said plurality of through-hole ports through at least in part capillary action; and

applying an electrical charge to said first fluid to evacuate said first fluid from at least one of said plurality of through-hole ports.