Microfabricated structures for facilitating fluid introduction into microfluidic devices

• US 7,364,916 B2
• Filed: 12/29/2006
• Issued: 04/29/2008
• Est. Priority Date: 06/06/1997
• Status: Expired due to Fees

• Current Assignee: Calvin Y.H. Chow, Parce J. Wallace, Steven A. Sundberg
• Original Assignee: Calvin Y.H. Chow, Parce J. Wallace, Steven A. Sundberg
• Inventors: Parce, J. Wallace, Chow, Calvin Y. H., Sundberg, Steven A.
• Primary Examiner(s): WALLENHORST, MAUREEN
• Application Number:
  US11/617,809
• Publication Number:
  US 20070110633A1
• Time in Patent Office: 487 Days
• Field of Search: 422/99, 422/100, 422/102, 436/174, 436/180
• US Class Current: 436/180
• 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 of retaining fluid for analysis, the method comprising:

retaining a first test fluid in a first through-hole port in a substrate by solely inducing capillary forces in said first fluid with said first through-hole port;

retaining a second test fluid in a second through-hole port in said substrate by solely inducing capillary forces in said second fluid with said second through-hole port; and

inhibiting cross-contamination between said first test fluid in said first through-hole port and said second test fluid in said second through-hole port with a hydrophobic coating along a surface of said substrate.

2. The method according to claim 1, further comprising:

transporting said first test fluid from outside said substrate to said first through-hole port.

3. The method according to claim 2 wherein said transporting said first test fluid from outside said substrate to said first through-hole port comprises retaining said first test fluid upon an exterior of a pin member and depositing said first test fluid in said first through-hole port.

4. The method according to claim 2 wherein said transporting said first test fluid from outside said substrate to said first through-hole port comprises retaining said first test fluid within a pipette and depositing said first test fluid in said first through-hole port.

5. The method according to claim 1 wherein said inhibiting cross-contamination with a hydrophobic coating along said surface of said substrate comprises inhibiting cross-contamination with a hydrophobic coating along a surface of said substrate adjacent an exit end of said first through-hole port.

6. The method according to claim 1, wherein said inhibiting cross-contamination with a hydrophobic coating along said surface of said substrate comprises inhibiting cross-contamination with a hydrophobic coating along a surface of said substrate adjacent an entrance end of said first through-hole port.

7. A method of retaining fluid for analysis, the method comprising:

retaining a first test fluid in a first through-hole port in a substrate by solely inducing capillary forces in said first fluid with said first through-hole port;

retaining a second test fluid in a second through-hole port in said substrate by solely inducing capillary forces in said second fluid with said second through-hole port; and

inhibiting flow of said first test fluid or said second test fluid between said first through-hole port and said second through-hole port using a hydrophobic coating disposed on said substrate.

8. The method according to claim 7, further comprising:

transporting said first test fluid from outside said substrate to said first through-hole port.

9. The method according to claim 8 wherein said transporting said first test fluid from outside said substrate to said first through-hole port comprises retaining said first test fluid upon an exterior of a pin member and depositing said first test fluid in said first through-hole port.

10. The method according to claim 8 wherein said transporting said first test fluid from outside said substrate to said first through-hole port comprises retaining said first test fluid within a pipette and depositing said first test fluid in said first through-hole port.

11. The method according to claim 7 wherein said inhibiting flow using said hydrophobic coating disposed on said substrate comprises inhibiting flow using a hydrophobic coating disposed along a surface of said substrate adjacent an exit end of said first through-hole port.

12. The method according to claim 7 wherein said inhibiting flow using said hydrophobic coating disposed on said substrate comprises inhibiting flow using a hydrophobic coating disposed along a surface of said substrate adjacent an entrance end of said first through-hole port.