Microfluidic device

• US 8,722,421 B2
• Filed: 12/14/2005
• Issued: 05/13/2014
• Est. Priority Date: 05/08/1998
• Status: Expired due to Fees

• Current Assignee: Gyros Patent AB (Mesa Laboratories Inc.)
• Original Assignee: Gyros Patent AB (Mesa Laboratories Inc.)
• Inventors: Andersson, Per, Allmer, Klas, Larsson, Anders
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Handy, Dwayne K
• Application Number:
  US11/302,713
• Publication Number:
  US 20060159592A1
• Time in Patent Office: 3,072 Days
• Field of Search: 422/64, 422/67, 422/72, 422/99, 422/100, 422/102, 422/502, 422/503, 422/504, 422/506, 436/45, 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 2219/00819 Materials of construction
• CPC Class Codes: B01J 2219/00833 Plastic
• CPC Class Codes: B01J 2219/00891 Feeding or evacuation
• CPC Class Codes: B01L 2300/0803 Disc shape
• CPC Class Codes: B01L 2300/0806 Standardised forms, e.g. compact disc [CD] format
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/089 Virtual walls for guiding liquids
• CPC Class Codes: B01L 2300/0893 having a very large number of wells, microfabricated wells
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0409 centrifugal forces
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/043 magnetic forces
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• CPC Class Codes: B01L 3/502723 characterised by venting arrangements
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B01L 3/502746 characterised by the means for controlling flow resistance, e.g. flow controllers, baffles B01L3/502738 takes precedence
• CPC Class Codes: B01L 3/502784 specially adapted for droplet or plug flow, e.g. digital microfluidics automatic analysis using a stream of discrete samples in a tube system G01N35/08
• CPC Class Codes: B01L 3/5085 for multiple samples, e.g. microtitration plates
• CPC Class Codes: B01L 3/5088 : confining liquids at a location by surface tension, e.g. virtual wells on plates, wires B01L3/50857 takes precedence
• CPC Class Codes: B29C 59/14 : by plasma treatment plasma tubes per se H01J
• CPC Class Codes: C12M 23/16 : Microfluidic devices; Capillary tubes integrated microfluidic structures B01L3/5027; microreactors B01J19/0093
• CPC Class Codes: G01N 2035/00495 : Centrifuges
• CPC Class Codes: G01N 2035/00524 : Mixing by agitating sample carrier
• CPC Class Codes: G01N 35/00069 : whereby the sample substrate is of the bio-disk type, i.e. having the format of an optical disk
• CPC Class Codes: Y10T 436/25 : including sample preparation
• CPC Class Codes: Y10T 436/2575 : Volumetric liquid transfer

Abstract

A microfluidic device adapted such that the flow of fluids within the device is controlled by different surfaces of the device having different surface characteristics. Preferably the device comprises a substrate not formed from a hydrated oxide material.

Claims

1. A microfluidic device comprising:

a circular device which is adapted for rotation about its axis and comprises two substrates, between which there are predetermined hydrophilic channels for liquid flow, and a first hydrophobic section within a hydrophilic channel, wherein at least one channel comprises the first hydrophobic section positioned between two hydrophilic sections in the channel, the hydrophobic section positioned to form a valve that provides a break in liquid flow passing through the channel, wherein the hydrophilic channel has a square or rectangular cross-section and comprises hydrophilic corners, and an additional hydrophobic surface area spaced from the hydrophobic section is applied to only one side of the channel to prevent capillary creep of liquid caused by the hydrophilic corners.

2. The microfluidic device of claim 1, wherein interior walls connecting the two substrates define the channels.

3. The microfluidic device of claim 1, wherein the device comprises an inlet towards the axis of the device.

4. The microfluidic device of claim 1, wherein the device comprises a series of inlet ports arranged at spaced intervals around the axis.

5. The microfluidic device of claim 1, wherein the device comprises an inlet for liquid towards the axis and an annular outlet for liquids towards the circumference of the device.

6. The microfluidic device of claim 1, wherein the channels comprise dimensions enabling capillary forces to act upon the liquid within the channels.

7. The microfluidic device of claim 1, wherein the surface within a channel is treated to enable a culture of cells.

8. The microfluidic device of claim 7, wherein the device further comprises a separate channel containing a hydrophobic section and the separate channel is a gas pathway or a sample inlet.

9. The microfluidic device of claim 8, wherein the separate channel is hydrophobic.

10. The device of claim 1, wherein the liquid comprises a surface tension>

18 mNm<sup>−

1</sup>.

11. The device of claim 1, wherein the liquid is an aqueous solution or suspension having a surface tension>

50 mNm<sup>−

1</sup>.

12. A method of producing a microfluidic device having the form of a disc which is adapted for rotation about an axis, and comprising two substrates, at least one of which controls flow of a liquid in the microfluidic device comprising the step of:

treating at least one substrate such that a surface of the treated substrate comprises hydrophilic channels for flow of the liquid and a hydrophobic section or valve within a hydrophilic channel, wherein at least one channel comprises a hydrophobic section positioned between two hydrophilic sections in the channel, the hydrophobic section positioned to prevent flow of the liquid, wherein the hydrophilic channel has a square or rectangular cross-section and comprises hydrophilic corners, and an additional hydrophobic surface area spaced from the hydrophobic section is applied to only one side of the channel to prevent capillary creep of liquid caused by the hydrophilic corners.

13. The method of claim 12, wherein the disc is circular.

14. The method of claim 12, wherein the microfluidic device comprises two parallel substrates for flow of liquids flowing in predetermined channels between the substrates.

15. The method of claim 12, wherein the channels comprise dimensions enabling capillary force to act upon the liquid within the channels.

16. The method of claim 12, wherein treating the surface of at least one of said substrates is selected from the group consisting of masking and plasma treatment, applying a cross-linkable hydrophilic photoresist, adsorbing a crosslinkable surface active polymer, adsorbing a polymerizable surfactant, applying photo-oxidation, applying electron beams, and a combination thereof.

17. A method for controlling flow of a liquid in a microfluidic device comprising the steps of:

providing a microfluidic device which is adapted for rotation about an axis and comprises two substrates, between which there are predetermined hydrophilic channels for liquid flow, and a hydrophobic section within a hydrophilic channel, wherein at least one channel comprises the first hydrophobic section positioned between two hydrophilic sections in the channel, the hydrophobic section positioned to form a valve that provides a break in liquid flow passing through the channel;

wherein the hydrophilic channel has a square or rectangular cross-section and comprises hydrophilic corners, and an additional hydrophobic surface area spaced from the hydrophobic section is applied to only one side of the channel to prevent capillary creep of liquid caused by the hydrophilic corners;

adding the liquid to an inlet of the microfluidic device, wherein the liquid flows down the hydrophilic channel until the liquid reaches the hydrophobic section or valve within the channel preventing the flow of liquid; and

applying sufficient energy to the liquid allowing it to pass the valve and continue to flow down the channel.

18. The method of claim 17, wherein the liquid flows down the hydrophilic channel to the valve by capillary action.

19. The method of claim 17, wherein the energy is centrifugal force created by rotating the device about the axis.

20. The method of claim 17, wherein the liquid comprises a surface tension>

18 mNm<sup>−

1</sup>.

21. The method of claim 17, wherein the liquid is an aqueous solution or suspension having a surface tension>

50 mNm<sup>−

1</sup>.

22. The method of claim 17, wherein the device is circular.