Methods for fabricating electrokinetic concentration devices

Patent metadata

Field	Value
Publication number	US-9360403-B2
Application number	US-201313861904-A
Country	US
Kind code	B2
Filing date	Apr 12, 2013
Priority date	Mar 26, 2008
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

The present invention provides a device and methods of use thereof in concentrating a species of interest and/or controlling liquid flow in a device. The methods make use of a device comprising a fluidic chip comprising a planar array of channels through which a liquid comprising a species of interest can be made to pass with at least one rigid substrate connected thereto such that at least a portion of a surface of the substrate bounds the channels, and a high aspect ratio ion-selective membrane is embedded within the chip, attached to at least a portion of the channels. The device comprises a unit to induce an electric field in the channel and a unit to induce an electrokinetic or pressure driven flow in the channel.

First claim

What is claimed is:

1. A method of concentrating a species of interest in a liquid, the method comprising applying said liquid comprising said species of interest to a concentrating device comprising:
a fluidic chip comprising a planar array of channels through which a liquid comprising a species of interest can be made to pass;
at least one rigid substrate connected thereto such that at least a portion of a surface of said substrate bounds said channels; and
a high aspect ratio ion-selective membrane embedded within said chip, attached to at least a portion of said channels.

2. The method of claim 1 , further comprising the steps of:
inducing an electric field in said channel whereby ion depletion occurs in a region in said channel proximal to said high aspect ratio ion-selective membrane, and a space charge layer is formed within said channel, which provides an energy barrier to said species of interest; and
inducing liquid flow in said channel.

3. The method of claim 2 , wherein said flow is electroosmotic.

4. The method of claim 2 , wherein said flow is pressure driven.

5. The method of claim 2 , wherein steps are carried out cyclically.

6. The method of claim 2 , wherein inducing an electric field in said channel is by applying voltage to said device.

7. The method of claim 6 , wherein said voltage is between 50 mV and 1500 V.

8. The method of claim 6 , wherein equal voltage is applied to opposing sides of said channel.

9. The method of claim 6 , wherein greater voltage is applied to the anodic side of said channel, as compared to the cathodic side.

10. The method of claim 9 , wherein a space charge layer is generated in said channel prior to applying said greater voltage to said anodic side of said channel.

11. The method of claim 1 , wherein said liquid comprises an organ homogenate, cell extract or blood sample.

12. The method of claim 1 , wherein said species of interest comprises proteins, polypeptides, nucleic acids, viral particles, or combinations thereof.

13. The method of claim 1 , wherein said device is coupled to a separation system, detection system, analysis system or combination thereof.

14. The method of claim 13 , wherein said detection system comprises fluorescence.

15. The method of claim 1 , wherein said high aspect ratio ion selective membrane is not in contact or is in minimal contact with said rigid substrate.

16. The method of claim 15 , wherein said no contact or minimal contact eliminates or reduces contamination of said rigid substrate by fluorescent molecules.

17. The method of claim 1 , wherein said concentrating results in large concentrated volumes of said species of interest.

18. The method of claim 17 , wherein said large concentrated volume of said species of interest is about 10 nL.

19. A method for the preparation of a concentrating device comprising:
a fluidic chip comprising a planar array of channels through which a liquid comprising a species of interest can be made to pass;
at least one rigid substrate connected thereto such that at least a portion of a surface of said substrate bounds said channels; and
a high aspect ratio ion-selective membrane embedded within said chip, attached to at least a portion of said channels;
said method comprising:
forming a high aspect ratio trench in said fluidic chip, such that the trench is perpendicular to the long axis of said channels, and such that the trench depth equals or exceeds the depth of said channels in said fluidic chip;
bending said fluidic chip parallel to the long axis of said trench, such that at least a portion of said trench becomes wider;
applying a liquid polymer to an area proximal to one end of said trench such that the liquid polymer is allowed to flow along the trench and fill the trench;
unbending said fluidic chip such that said liquid polymer is strongly adhered to said trench;
providing conditions such that said liquid polymer forms a high aspect ratio ion selective membrane embedded in said trench; and
optionally removing residues of said polymer from areas of said fluidic chip proximal to the trench;
attaching said one rigid substrate to said fluidic chip comprising channels such that said channels bound at least a portion of a surface of said substrate.

20. The method of claim 19 , wherein said fluidic chip comprises channels having a width of between 10-200 μm.

21. The method of claim 19 , wherein said fluidic chip comprises channels having a depth of between 5-100 μm.

22. The method of claim 19 , wherein said high aspect ratio ion selective membrane has a width of between about 0.1-100 μm.

23. The method of claim 19 , wherein said high aspect ratio ion selective membrane has a width of between about 1-6 μm.

24. The method of claim 19 , wherein said high aspect ratio ion selective membrane has a non-uniform width.

25. The method of claim 19 , wherein said high aspect ratio ion selective membrane has a depth of between about 10-1000 μm.

26. The method of claim 19 , wherein said high aspect ratio ion selective membrane has a depth of between about 500-850 μm.

27. The method of claim 19 , wherein said high aspect ratio ion selective membrane has a depth of between about 750-1250 μm.

28. The method of claim 19 , wherein said rigid substrate comprises pyrex, silicon, silicon dioxide, silicon nitride, quartz, PMMA, PC or acryl.

29. The method of claim 19 , wherein said fluidic chip comprises polydimethylsiloxane.

30. The method of claim 19 wherein said liquid polymer comprises polytetrafluoroethylenes, polyphosphazenes, polybenzimidazoles (PBIs), poly-zirconia, polyethyleneimine-poly(acrylic acid), or poly(ethylene oxide)-poly(acrylic acid).

31. The method of claim 19 , wherein said liquid polymer comprises sulfonated tetrafluorethylene copolymer.

32. The method of claim 31 , wherein said sulfonated tetrafluorethylene copolymer comprises a Nafion solution.

33. The method of claim 19 , wherein said high aspect ratio membrane comprises microparticles or beads.

34. The method of claim 33 , wherein said microparticles or beads comprising silica or polystyrene.

35. The method of claim 19 , wherein providing conditions such that said liquid polymer forms a high aspect ratio ion selective membrane embedded in said trench is accomplished by heating said liquid polymer.

36. The method of claim 35 , wherein said heating is conducted at a temperature of about 95° C.

37. The method of claim 35 , wherein said heating is performed for about 10 minutes.

38. The method of claim 19 , wherein attaching said substrate to said fluidic chip is done by plasma bonding.

39. The method of claim 19 , wherein said liquid polymer at least partially fills said channels in an area proximal to said high aspect ion selective membrane.

40. The method of claim 19 , wherein said high aspect ratio ion selective membrane is not in contact or is in minimal contact with said rigid substrate.

Assignees

• Han Jongyoon
• Kim Sung Jae
• Massachusetts Inst Technology

Inventors

• Han Jongyoon
• Kim Sung Jae

Classifications

• B01L2400/0487

  fluid pressure, pneumatics · CPC title

• B01L2200/0631

  Purification arrangements, e.g. solid phase extraction [SPE] · CPC title

• B01L2300/0681

  Filter · CPC title

• B01L3/502707

  characterised by the manufacture of the container or its components · CPC title

• Y10T156/1002

  with permanent bending or reshaping or surface deformation of self sustaining lamina · CPC title