Printed digital microfluidic devices methods of use and manufacture thereof

• US 9,594,056 B2
• Filed: 02/27/2014
• Issued: 03/14/2017
• Est. Priority Date: 10/23/2013
• Status: Active Grant

• Current Assignee: The Governing Council of the University of Toronto (University of Toronto)
• Original Assignee: The Governing Council of the University of Toronto (University of Toronto)
• Inventors: Fobel, Ryan, Kirby, Andrea, Wheeler, Aaron
• Primary Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US14/192,737
• Publication Number:
  US 20150107998A1
• Time in Patent Office: 1,111 Days
• US Class Current: 1/1
• CPC Class Codes: B01L 2200/0668 Trapping microscopic beads
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/126 Paper
• CPC Class Codes: B01L 2400/0427 Electrowetting
• CPC Class Codes: B01L 2400/043 magnetic forces
• CPC Class Codes: B01L 3/5023 with a sample being transported to, and subsequently stored in an absorbent for analysis
• 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 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: B41J 2/01 Ink jet
• CPC Class Codes: B41M 5/0023 Digital printing methods characterised by the inks used inks per se C09D11/00
• CPC Class Codes: B41M 5/0047 by ink-jet printing
• CPC Class Codes: B41M 5/0058 on metals and oxidised metal surfaces
• CPC Class Codes: B41M 5/0064 on plastics, horn, rubber, or other organic polymers
• CPC Class Codes: B41M 5/007 on glass, ceramic, tiles, concrete, stones, etc.
• CPC Class Codes: B81B 2201/058 Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: B81C 1/00095 Interconnects
• CPC Class Codes: B81C 1/00166 : Electrodes
• CPC Class Codes: B81C 2201/0184 : Digital lithography, e.g. using an inkjet print-head
• CPC Class Codes: B81C 2201/0185 : Printing, e.g. microcontact printing
• CPC Class Codes: G01N 27/44743 : Introducing samples
• CPC Class Codes: G01N 27/44791 : Microapparatus sample containers with integrated microfluidic structures B01L3/5027

Abstract

Embodiments of the present disclosure digital microfluidic arrays that may be fabricated by a printing method, whereby digital microfluidic electrodes arrays are printed, via a printing method such as inkjet printing, onto a suitable substrate. In some embodiments, a substrate and/or ink is prepared or modified to support the printing of electrode arrays, such as via changes to the surface energy. In some embodiments, porous and/or fibrous substrates are prepared by the addition of a barrier layer, or, for example, by the addition or infiltration of a suitable material to render the surface capable of supporting printed electrodes. Various example embodiments involving hybrid devices formed by the printing of digital microfluidic arrays onto a substrate having a hydrophilic layer are disclosed.

Claims

1. A digital microfluidic device comprising:

a porous substrate having a surface adapted to support electrodes thereon, said porous substrate comprising;

a porous layer formed from a fibrous material; and

a barrier layer provided on said porous layer, wherein said barrier layer is formed from a barrier material suitable for the formation of electrodes thereon;

an array of digital microfluidic electrodes printed on said porous substrate; and

a dielectric layer coating said array of digital microfluidic electrodes, wherein a surface of said dielectric layer is hydrophobic;

wherein a surface roughness of said barrier layer is less than 1 micron, such that said array of digital microfluidic electrodes are suitable for transporting droplets among said digital microfluidic electrodes under electrical actuation, further wherein said barrier layer is a first barrier layer, and said porous layer is a hydrophilic layer, and said porous substrate further comprises a second barrier layer below said hydrophilic layer.

2. The digital microfluidic device according to claim 1 wherein at least an upper portion of said porous substrate is infiltrated.

3. The digital microfluidic device according to claim 1 wherein an inter-electrode trench width is between approximately 5-100 microns.

4. The digital microfluidic device according to claim 1 wherein an inter-electrode trench width is between approximately 5 and 50 microns.

5. The digital microfluidic device according to claim 1 wherein an inter-electrode trench width is between approximately 60 and 90 microns.

6. The digital microfluidic device according to claim 1 wherein an inter-electrode trench depth is less than approximately 1 micron.

7. The digital microfluidic device according to claim 6 wherein said inter-electrode trench depth is less than approximately 500 nm.

8. The digital microfluidic device according to claim 1 wherein the surface roughness of said array of digital microfluidic electrodes is less than approximately 500 nm.

9. The digital microfluidic device according to claim 8 wherein said surface roughness of said array of digital microfluidic electrodes is less than approximately 100 nm.

10. The digital microfluidic device according to claim 1 wherein said fibrous material is a paper-based material.

11. The digital microfluidic device according to claim 10 wherein said fibrous material comprises a cellulosic material.

12. The digital microfluidic device according to claim 1 wherein said fibrous material is a synthetic fibrous material.

13. The digital microfluidic device according to claim 1 wherein said barrier layer comprises kaolin and latex.

14. The digital microfluidic device according to claim 1 wherein said barrier layer is formed directly on said porous layer.

15. The digital microfluidic device according to claim 1 wherein said array of digital microfluidic electrodes is formed directly on said barrier layer.

16. The digital microfluidic device according to claim 1, wherein at least one portion of said first barrier layer removed, thereby exposing a region of said hydrophilic layer.

17. The digital microfluidic device according to claim 16 wherein said region is an electrospray tip formed in said hydrophilic layer.

18. The digital microfluidic device according to claim 16 wherein said region resides below an electrode of said array of digital microfluidic electrodes, and wherein an aperture is formed in said electrode to expose said region.

19. The digital microfluidic device according to claim 18 wherein said hydrophilic layer comprises a microchannel, wherein said microchannel is in fluid communication with a droplet contacting said aperture.

20. The digital microfluidic device according to claim 19 wherein said microchannel is defined by hydrophobic walls formed within said hydrophilic layer.

21. The digital microfluidic device according to claim 18 wherein said hydrophilic layer comprises a lateral flow channel, wherein said lateral flow channel is in fluid communication with a droplet contacting said aperture.

22. The digital microfluidic device according to claim 19 wherein a portion of said microchannel is adjacent to said aperture.

23. The digital microfluidic device according to claim 18 wherein an exposed region of said hydrophilic layer beneath said aperture is surrounded by a hydrophobic wall, thereby forming a hydrophilic pad beneath said aperture.

24. The digital microfluidic device according to claim 23 wherein said hydrophilic pad comprises a dried reagent.

25. The digital microfluidic device according to claim 23 wherein said hydrophilic pad comprises a dried sample.

26. The digital microfluidic device according to claim 1 further comprising a top plate provided in a spaced relationship from said digital microfluidic device, said top plate comprising at least one electrode coated with a dielectric layer, wherein said dielectric layer has a hydrophobic surface.

27. A digital microfluidic device comprising:

a porous substrate having a surface adapted to support electrodes thereon, said porous substrate comprising;

a porous layer formed from a fibrous material; and

a barrier layer provided on said porous layer, wherein said barrier layer is formed from a barrier material suitable for the formation of electrodes thereon;

an array of digital microfluidic electrodes formed on said porous substrate; and

a dielectric layer coating said array of digital microfluidic electrodes, wherein a surface of said dielectric layer is hydrophobic;

wherein a surface roughness of said barrier layer is less than 1 micron, such that of said array of digital microfluidic electrodes are suitable for transporting droplets among said digital microfluidic electrodes under electrical actuation

further wherein said barrier layer is a first barrier layer, and said porous layer is a hydrophilic layer, and said porous substrate further comprises a second barrier layer below said hydrophilic layer.