Microfabricated structures for facilitating fluid introduction into microfluidic devices

• US 7,259,020 B2
• Filed: 07/30/2002
• Issued: 08/21/2007
• Est. Priority Date: 06/06/1997
• Status: Expired due to Term

• Current Assignee: Applied Biosystems LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Applera Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Parce, J. Wallace, Chow, Calvin Y. H., Sundberg, Steven A.
• Primary Examiner(s): WALLENHORST, MAUREEN
• Application Number:
  US10/208,297
• Publication Number:
  US 20020185377A1
• Time in Patent Office: 1,848 Days
• Field of Search: 436/175, 436/177, 436/178, 436/180, 422/100, 422/101, 204/453
• 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 filtered microfluidic device comprising a substrate having:

a reservoir;

a microfluidic channel having a microfluidic cross-section; and

a plurality of filter channels disposed in fluid communication between the reservoir and the microfluidic channel, each of the plurality of filter channels having a cross-sectional dimension which is smaller than a cross-sectional dimension of the microfluidic channel, a sum of the cross-sectional dimensions of the plurality of filter channels is greater than or equal to the cross-sectional dimensions of the microfluidic channel to minimize head loss when at least one of the plurality of filter channels is blocked.

2. A filtered microfluidic device as claimed in claim 1, wherein the filter channel cross-sectional dimensions prevent the transport of particles from the reservoir through the plurality of filter channels which are large enough to block the microfluidic channel.

3. A filtered microfluidic device as claimed in claim 1, wherein each of the plurality of filter channels has a first end and a second end, the first end opening to the reservoir, the second end opening to a header channel, the header channel being disposed between the plurality of filter channels and the microfluidic channel and being in fluid communication therewith.

4. A filtered microfluidic device as claimed in claim 1, wherein the microfluidic channel has a minimum cross sectional dimension of within the range from about 1 μ

m to 100 μ

m, and wherein the filter channels each have a minimum cross-sectional dimension which is less than about ½

of the minimum cross-sectional dimension of the microfluidic channel.

5. A filtered microfluidic device as claimed in claim 1, further comprising a port in fluid communication with the microfluidic channel, wherein fluid can enter the microfluidic channel from the port without passing through the plurality of filter channels.

6. A filtered microfluidic device comprising:

a reservoir;

a microfluidic channel having a microfluidic cross-section; and

a plurality of filter channels disposed in fluid communication between the reservoir and the microfluidic channel, each of the plurality of filter channels extends radially from the reservoir, each of the plurality of filter channels having a cross-sectional dimension smaller than a cross-sectional dimension of the microfluidic channel, thereby preventing the transport of particles from the reservoir through the filter channels which are large enough to block the microfluidic channel, and wherein a sum of the cross-sections of the plurality of filter channels is larger than the cross-section of the microfluidic channel to minimize head loss when at least one of the filter channels is blocked.

7. A filtered microfluidic device as claimed in claim 6, further comprising:

a header channel extending circumferentially around the reservoir.

8. A method for filtering a fluid sample entering a microfluidic channel network, the method comprising:

introducing the fluid sample into a port comprising a plurality of filter channels in parallel;

passing the fluid sample through the plurality of filter channels, the filter channels blocking particles having cross sections which are larger than a maximum filter particle size; and

collecting the filtered fluid sample and transporting the filtered fluid sample through a microfluidic channel having a cross-section which is larger than the maximum filter particle size,

wherein a sum of the cross-sectional dimensions of the plurality of filter channels is greater than or equal to the cross-sectional dimensions of the microfluidic channel to minimize head loss when at least one of the plurality of filter channels is blocked.

9. A method as claimed in claim 8, further comprising introducing another fluid through another port and advancing the other fluid through the microfluidic channel and the filter channels prior to introducing the fluid sample.

10. A microfluidic device comprising a substrate having:

a reservoir;

a microfluidic channel having a microfluidic cross-section; and

a plurality of filter channels radially extending from the reservoir, the plurality of filter channels being disposed in fluid communication between the reservoir and the microfluidic channel, each filter channel having a cross-sectional dimension which is smaller than a cross-sectional dimension of the microfluidic channel.

11. The microfluidic device as claimed in claim 10, further comprising:

a header channel circumferentially disposed between the plurality of filter channels and the microfluidic channel, the header channel being in fluid communication between the plurality of filter channels and the microfluidic channel.