Microfabricated structures for facilitating fluid introduction into microfluidic devices

• US 7,364,703 B2
• Filed: 07/27/2006
• 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:
  US11/493,996
• Publication Number:
  US 20060286000A1
• Time in Patent Office: 642 Days
• Field of Search: 422/99, 422/100, 422/102, 436/174, 436/180
• US Class Current: 422/507
• 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 microfluidic system comprising:

a pin member having a test fluid contained thereon; and

a substrate having a plurality of ports extending from a first surface of said substrate to a second surface of said substrate, each of said plurality of ports being sized to transfer said test fluid from said pin member to said plurality of ports in response to capillary force when said pin member is brought into sufficient proximity to said plurality of ports.

2. The microfluidic system according to claim 1 wherein each of said plurality of ports is sized to retain said test fluid from said pin member in said plurality of ports solely by capillary force.

3. The microfluidic system according to claim 1 wherein said pin member is sufficient sized to retain a portion of said test fluid when dipped into a fluid receptacle.

4. The microfluidic system according to claim 1 wherein said test fluid is solely contained on an exterior portion of said pin member.

5. The microfluidic system according to claim 1 wherein said second surface of said substrate is hydrophobic.

6. A microfluidic system comprising:

a pin member having a test fluid contained thereon;

a substrate having a plurality of ports extending from a first surface of said substrate to a second surface of said substrate, each of said plurality of ports being sized to transfer said test fluid from said pin member to said plurality of ports when said pin member is brought into sufficient proximity to said plurality of ports; and

a channel disposed in a fluid support structure, said pin member extending from said fluid support structure, said channel being in fluid communication with said pin member and delivering said test fluid thereto.

7. A microfluidic system comprising:

a pin member having a test fluid contained thereon;

a substrate having a plurality of ports extending from a first surface of said substrate to a second surface of said substrate, each of said plurality of ports being sized to transfer said test fluid from said pin member to said plurality of ports when said pin member is brought into sufficient proximity to said plurality of ports; and

a rod disposed below at least one of said plurality of ports, said rod extending upward toward said at least one of said plurality of ports to encourage decanting of said test fluid therefrom.

8. The microfluidic system according to claim 7 wherein said second surface of said substrate is hydrophobic and said rod is hydrophilic.

9. A method comprising:

inserting a pin member into a test fluid so as to retain at least a portion of said test fluid on said pin member;

positioning said pin member in sufficient proximity to a port formed in a substrate to transfer said test fluid from said pin member to said port in response to a capillary force, said port extending through said substrate from a first surface to a second surface; and

retaining said test fluid in said port solely by capillary force.

10. The method according to claim 9, further comprising:

decanting said test fluid from said port by inserting an upwardly extending rod to contact said test fluid.

11. The method according to claim 9, further comprising:

decanting said test fluid from said port by inserting an upwardly extending hydrophilic rod to contact said test fluid.