Fabrication and integration of polymeric bioMEMS

• US 20050230767A1
• Filed: 12/03/2004
• Published: 10/20/2005
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: University of Maryland Biotechnology Institute, University of Maryland, College Park
• Original Assignee: University of Maryland Biotechnology Institute, University of Maryland, College Park
• Inventors: Wu, Li-Qun, Yi, Hyunmin, Rubloff, Gary W., Ghodssi, Reza, Li, Sheng, Valentine, Theresa Michelle, Kastantin, Mark Joseph, Park, Jung Jin
• Granted Patent: US 7,375,404 B2
• Time in Patent Office: Days
• US Class Current: 257/414
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2200/0689 Sealing
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/041 Connecting closures to device or container
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0803 Disc shape
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0887 Laminated structure
• 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: B81B 2201/058 Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: B81B 7/0061 suitable for fluid transfer from the MEMS out of the package or vice versa, e.g. transfer of liquid, gas, sound
• CPC Class Codes: B81C 3/002 Aligning microparts

Abstract

A micro-electro-mechanical system (MEMS) device is provided, along with means for its fabrication and operation for microfluidic and/or biomicrofluidic applications. The MEMS device includes a substrate, optional electrodes on the substrate, a patterned structure on the substrate, the patterned structure having a fluidic microchannel aligned with one or more of the optional electrodes, an encapsulation membrane covering the microchannel, and an optional reactive layer deposited over the electrode in the microchannel. MEMS devices of preferred embodiments permit a leak-tight seal to be formed around the microchannel and fluidic interconnects established for robust operation of fluidics-based processes. MEMS devices of other preferred embodiments permit reversible attachment and separation of the encapsulation membrane relative to the patterned structure.

Claims

1. A micro-electro-mechanical system (MEMS) device, comprising:

a substrate;

a patterned structure on the substrate, the patterned structure having a microchannel; and

an encapsulation membrane covering the microchannel, the encapsulation membrane being reversibly attachable and separable with respect to the patterned structure.

2. The device of claim 1, wherein:

the patterned structure comprises an epoxy; and

the polymeric encapsulation membrane comprises polydimethylsiloxane.

3. The device of claim 1, wherein the patterned structure comprises SU-8.

4. The device of claim 1, wherein the patterned structure further has a fluid inlet reservoir and a fluid outlet reservoir, the microchannel connecting the fluid inlet and outlet reservoirs to one another.

5. The device of claim 4, wherein the encapsulation layer comprises an inlet port and an outlet port in communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively.

6. The device of claim 1, wherein the patterned structure comprises a first layer and a second layer, the first layer containing the microchannel, the second layer establishing a component of an alignment mechanism for mating with a corresponding component of the encapsulation membrane for permitting reversible alignment, attachment and removal of the encapsulation membrane with respect to the patterned structure.

7. The device of claim 6, wherein:

the second layer defines alignment posts; and

the encapsulation membrane comprises holes for receiving the alignment posts.

8. The device of claim 1, further comprising first and second electrodes situated on the substrate, the first electrode being aligned with the microchannel.

9. The device of claim 8, wherein the first electrode comprises polypyrrole.

10. The device of claim 8, further comprising a reactive layer deposited over the first electrode in the microchannel.

11. The device of claim 10, wherein the reactive layer comprises chitosan.

12. The device of claim 10, further comprising molecules conjugated to the reactive layer, the molecular selected from biomolecular and cellular species.

13. A method of operating and accessing a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of any one of claim 1;

placing the encapsulation membrane on the patterned structure to cover the microchannel;

passing a fluid through the microchannel;

reversibly removing the encapsulating membrane to expose the microchannel; and

reapplying the encapsulation membrane to the patterned structure.

14. A method of depositing molecules in a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 12;

placing the encapsulation membrane on the patterned structure to cover the microchannel;

introducing an aqueous solution into the microchannel, the aqueous solution containing the reactive layer and molecules dissolved therein;

applying a voltage to the first electrode and depositing the reactive layer and conjugated molecules in the microchannel over the first electrode;

reversibly removing the encapsulating membrane to expose the microchannel; and

reapplying the encapsulation membrane to the patterned structure.

15. A micro-electro-mechanical system (MEMS) device, comprising:

a substrate;

a patterned structure on the substrate, the patterned structure comprising SU-8 and having a microchannel; and

a polydimethylsiloxane encapsulation membrane covering the microchannel.

16. The device of claim 15, wherein the patterned structure further has a fluid inlet reservoir and a fluid outlet reservoir, the microchannel connecting the fluid inlet and outlet reservoirs to one another.

17. The device of claim 15, further comprising first and second electrodes situated on the substrate, the first electrode being aligned with the microchannel.

18. The device of claim 17, wherein the first electrode comprises polypyrrole.

19. The device of claim 17, further comprising a reactive layer deposited over the first electrode in the microchannel.

20. The device of claim 19, wherein the reactive layer comprises chitosan.

21. The device of claim 19, further comprising molecules conjugated to the reactive layer, the molecular selected from biomolecular and cellular species.

22. A method of operating a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 15;

and

passing a fluid through the microchannel.

23. A method of depositing molecules in a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 21;

introducing an aqueous solution into the microchannel, the aqueous solution containing the reactive layer and molecules dissolved therein; and

applying a voltage to the first electrode and depositing the reactive layer and conjugated molecules in the microchannel over the first electrode.

24. A micro-electro-mechanical system (MEMS) device, comprising:

a substrate;

a patterned structure on the substrate, the patterned structure comprising an inlet reservoir, an outlet reservoir, and a microchannel; and

an encapsulation membrane covering the microchannel, the encapsulation membrane comprising an inlet port in fluid communication with the inlet reservoir and an outlet port in fluid communication with the outlet reservoir.

25. The device of claim 24, wherein:

the patterned structure comprises an epoxy; and

the encapsulation membrane comprises polydimethylsiloxane.

26. The device of claim 24, wherein the patterned structure comprises SU-8.

27. The device of claim 24, further comprising:

a first wafer adjacent the substrate and on an opposite side of the substrate relative to the patterned structure; and

a second wafer adjacent the encapsulation membrane and on an opposite side of the encapsulation membrane relative to the patterned structure, the second wafer comprising an inlet channel and an outlet channel in fluid communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively.

28. The device of claim 27, further comprising:

a first frame on an opposite side of the first wafer relative to the substrate; and

a second frame on an opposite side of the second wafer relative to the encapsulation membrane, the second frame comprising a frame inlet channel and a frame outlet channel in fluid communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively.

29. The device of claim 28, further comprising a gasket layer between the first frame and the first wafer.

30. The device of claim 29, further comprising a compression mechanism applying a compressive force to outer surfaces of the first and second frames.

31. The device of claim 24, further comprising first and second electrodes situated on the substrate, the first electrode being aligned with the microchannel.

32. The device of claim 31, wherein the first electrode comprises polypyrrole.

33. The device of claim 31, further comprising a reactive layer deposited over the first electrode in the microchannel.

34. The device of claim 33, wherein the reactive layer comprises chitosan.

35. The device of claim 33, further comprising molecules conjugated to the reactive layer, the molecular selected from biomolecular and cellular species.

36. A method of operating a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of any one of claim 24;

and

introducing fluid into the inlet port for delivery to the inlet reservoir;

passing the fluid from the inlet reservoir along the microchannel and into the outlet reservoir; and

removing the fluid from the outlet reservoir through the outlet port.

37. A method of depositing molecules in a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 35;

introducing an aqueous solution containing the reactive layer and molecules dissolved therein to the inlet port for delivery to the inlet reservoir;

passing the aqueous solution from the inlet reservoir along the microchannel; and

applying a voltage to the first electrode and depositing the reactive layer and conjugated molecules in the microchannel over the first electrode.

38. A micro-electro-mechanical system (MEMS) device, comprising:

a substrate;

a patterned structure on the substrate, the patterned structure comprising a first layer and a second layer, the first layer having a microchannel, the second layer comprising a ridge protruding from the first layer and surrounding the microchannel; and

a compressible sealing layer covering the microchannel and compressed against the ridge to provide a leak-tight seal.

39. The device of claim 38, wherein:

the patterned structure comprises an epoxy; and

the compressible sealing layer comprises polydimethylsiloxane.

40. The device of claim 38, wherein the patterned structure comprises SU-8.

41. The device of claim 38, wherein the ridge has a rounded profile.

42. The device of claim 38, wherein the ridge has a sharp edge profile.

43. The device of claim 38, wherein:

the patterned structure further has a fluid inlet reservoir and a fluid outlet reservoir, the microchannel connecting the fluid inlet and outlet reservoirs to one another; and

the encapsulation membrane comprises an inlet port in fluid communication with the inlet reservoir and an outlet port in fluid communication with the outlet reservoir.

44. The device of claim 43, further comprising:

a first wafer adjacent the substrate and on an opposite side of the substrate relative to the patterned structure; and

a second wafer adjacent the encapsulation membrane and on an opposite side of the compressible sealing layer relative to the patterned structure, the second wafer comprising an inlet channel and an outlet channel in fluid communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively.

45. The device of claim 44, further comprising:

a first frame on an opposite side of the first wafer relative to the substrate;

a second frame on an opposite side of the second wafer relative to the compressible sealing layer, the second frame comprising a frame inlet channel and a frame outlet channel in fluid communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively; and

a clamp mechanism applying a compressive force to outer surfaces of the first and second frames and establishing the leak-tight seal between the patterned structure and the compressible sealing layer.

46. The device of claim 38, further comprising first and second electrodes situated on the substrate, the first electrode being aligned with the microchannel.

47. The device of claim 46, wherein the first electrode comprises polypyrrole.

48. The device of claim 46, further comprising a reactive layer deposited over the first electrode in the microchannel.

49. The device of claim 48, wherein the reactive layer comprises chitosan.

50. The device of claim 48, further comprising molecules conjugated to the reactive layer, the molecular selected from biomolecular and cellular species.

52. A method of depositing molecules in a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 50;

applying a compressive force to form the leak-tight seal between the patterned structure and the compressible sealing layer;

introducing an aqueous solution containing the reactive layer and molecules dissolved therein into the microchannel; and

applying a voltage to the first electrode and depositing the reactive layer and conjugated molecules in the microchannel over the first electrode.

51. A method of operating a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of dais 38;

applying a compressive force to form the leak-tight seal between the patterned structure and the compressible sealing layer; and

flowing fluid through the microchannel.

53. A micro-electro-mechanical system (MEMS) device, comprising:

a substrate;

a patterned ridge structure on the substrate, the patterned ridge structure forming and surrounding a microchannel; and

a compressible sealing layer covering the microchannel and compressed against the ridge structure to provide a leak-tight seal.

54. The device of claim 53, wherein:

the patterned ridge structure comprises an epoxy; and

the compressible sealing layer comprises polydimethylsiloxane.

55. The device of claim 53, wherein the patterned ridge structure comprises SU-8.

56. The device of claim 53, wherein ridges of the patterned ridge structure have a rounded profile.

57. The device of claim 53, wherein ridges of the patterned ridge structure have a sharp edge profile.

58. The device of claim 53, wherein:

the patterned ridge structure further has a fluid inlet reservoir and a fluid outlet reservoir, the microchannel connecting the fluid inlet and outlet reservoirs to one another; and

the compressible sealing layer comprises an inlet port in fluid communication with the inlet reservoir and an outlet port in fluid communication with the outlet reservoir.

59. The device of claim 58, further comprising:

a first wafer adjacent the substrate and on an opposite side of the substrate relative to the patterned ridge structure; and

a second wafer adjacent the compressible sealing layer and on an opposite side of the compressible sealing layer relative to the patterned ridge structure, the second wafer comprising an inlet channel and an outlet channel in fluid communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively.

60. The device of claim 59, further comprising:

a first frame on an opposite side of the first wafer relative to the substrate;

a second frame on an opposite side of the second wafer relative to the compressible sealing layer, the second frame comprising a frame inlet channel and a frame outlet channel in fluid communication with the fluid inlet reservoir and the fluid outlet reservoir, respectively; and

a clamp mechanism applying a compressive force to outer surfaces of the first and second frames and establishing the leak-tight seal between the compressible sealing layer and the patterned ridge structure.

61. The device of claim 53, further comprising first and second electrodes situated on the substrate, the first electrode being aligned with the microchannel.

62. The device of claim 61, wherein the first electrode comprises polypyrrole.

63. The device of claim 61, further comprising a reactive layer deposited over the first electrode in the microchannel.

64. The device of claim 63, wherein the reactive layer comprises chitosan.

65. The device of claim 63, further comprising molecules conjugated to the reactive layer, the molecular selected from biomolecular and cellular species.

66. A method of operating a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 53;

applying a compressive force to form the leak-tight seal between the patterned ridge structure and the compressible sealing layer; and

flowing fluid through the microchannel.

67. A method of depositing molecules in a micro-electro-mechanical system (MEMS) device, comprising:

providing the micro-electro-mechanical system (MEMS) device of claim 65;

applying a compressive force to form the leak-tight seal between the patterned ridge structure and the compressible sealing layer;

introducing an aqueous solution containing the reactive layer and molecules dissolved therein into the microchannel; and

applying a voltage to the first electrode and depositing the reactive layer and conjugated molecules in the microchannel over the first electrode.