Microstructure fabrication and microsystem integration

• US 20030214057A1
• Filed: 02/11/2003
• Published: 11/20/2003
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: Zhili Huang
• Original Assignee: Zhili Huang
• Inventors: Huang, Zhili
• Granted Patent: US 7,125,510 B2
• Time in Patent Office: Days
• US Class Current: 264/1.1
• 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 2219/00833 Plastic
• CPC Class Codes: B01J 2219/00873 Heat exchange
• CPC Class Codes: B01J 2219/0095 Control aspects
• CPC Class Codes: B01J 2219/0097 Optical sensors
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0654 Lenses; Optical fibres
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2400/0481 squeezing of channels or chambers
• 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 3/502715 characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• 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: B29C 33/0033 constructed for making articles provided with holes
• CPC Class Codes: B29C 33/3842 Manufacturing moulds, e.g. shaping the mould surface by machining
• CPC Class Codes: B29C 33/52 soluble or fusible in particular used in injection moulding B29C45/4457
• CPC Class Codes: B29C 39/10 incorporating preformed parts or layers, e.g. casting around inserts or for coating articles coating a surface by casting in general B05D1/30, B29C39/126 takes precedence
• CPC Class Codes: B29C 39/34 for undercut articles
• CPC Class Codes: B29C 39/36 : Removing moulded articles
• CPC Class Codes: B29L 2011/0016 : Lenses
• CPC Class Codes: B29L 2011/0075 : Light guides, optical cables
• CPC Class Codes: B29L 2031/3406 : Components, e.g. resistors
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: G01N 27/44721 : by optical means
• CPC Class Codes: G01N 27/44791 : Microapparatus sample containers with integrated microfluidic structures B01L3/5027

Abstract

Fabrication of a microstructure device includes assembling a mold component and a mold body to form a device mold for the microstructure device. The microstructure device is cast from the device mold, then the mold component is removed from the microstructure device. The microstructure device is then released from the mold body.

Claims

1. A method of fabricating a microstructure device, comprising:

assembling a mold component and a mold body to form a device mold for the microstructure device;

casting the microstructure device from the device mold;

removing the mold component from the microstructure device; and

releasing the microstructure device from the mold body.

2. The method of claim 1 wherein casting the microstructure device comprises pouring or injecting a liquid polymer into the device mold.

3. The method of claim 2, further comprising combining the liquid polymer with a filler material or reinforcement particles.

4. The method of claim 2 wherein the liquid polymer comprises polyurethane, polydimethylsiloxane, polycarbonate, polypyrrole, resin, Teflon resin, epoxy, polymeric rubber, or polymeric plastic.

5. The method of claim 1 wherein the mold component comprises wax, gel, fusible alloy, eutectic alloy, resin, lipid, or ammonium salt.

6. The method of claim 1 wherein the mold component has structures having a dimension less than 5 millimeters.

7. The method of claim 1 wherein the mold component comprises a reversible material that changes from a solid form to a liquid form or from a liquid Finn to a solid form depending on changes in one or more environment conditions.

8. The method of claim 7 wherein removing the mold component comprises changing the one or more environment conditions so that the reversible mold component changes from a solid form to a liquid form.

9. The method of claim 7 wherein removing the mold component comprises applying a centrifugal force to draw the mold component in liquid form away from the microstructure device.

10. The method of claim 7 wherein removing the mold component comprises using a suction force to draw the mold component in liquid form away from the microstructure device.

11. The method of claim 1 wherein the mold component comprises a material that changes from a solid form to a gaseous form or from a gaseous form to a solid form depending on changes in one or more environment conditions.

12. The method of claim 11 wherein removing the mold component comprises changing the one or more environment conditions so that the mold component changes from a solid form to a gaseous form.

13. The method of claim 1 wherein the mold component comprises a soluble material that can be cast into a predefined shape as defined by a mold and later be dissolved in a solvent.

14. The method of claim 13 wherein removing the mold component comprises flushing the mold component out from the microstructure device with a solvent that dissolves the mold component.

15. The method of claim 1 wherein the mold component has a shape that is complementary of a structure of the microstructure device after the mold component is removed from the microstructure device.

16. The method of claim 1 wherein the mold component comprises an elongated mold component having a same dimension and shape as a channel in the microstructure device after the mold component is removed from the microstructure device.

17. The method of claim 1, further comprising fabricating the mold component by using a component mold.

18. The method of claim 17 wherein fabricating the mold component comprises pouring a material in a liquid form into the component mold, and changing one or more environment conditions so that the material changes to a solid or gel form.

19. The method of claim 17 wherein the component mold has a cavity having a shape that is substantially the same as a shape of the mold component, the cavity being connected to an exterior of the component mold through an opening, wherein fabricating the mold component comprises injecting a material in a liquid form into the cavity through the opening, and changing one or more environment conditions so that the material changes to a solid or gel form.

20. The method of claim 17, wherein the component mold has a cavity having a shape that is substantially the same as a shape of the mold component, wherein fabricating the mold component comprises compressing a material in powder form into the cavity to form the mold component.

21. A method, comprising:

assembling a set of mold components and a mold body to form a device mold for a microstructure device;

casting the microstructure device from the device mold; and

removing the set of mold components from the microstructure device.

22. The method of claim 21 wherein casting the microstructure device comprises pouring or injecting a liquid polymer into the device mold.

23. The method of claim 21 wherein the set of mold components includes a first mold component and a second mold component, the first mold component having a shape configured so that a first chamber is formed in the microstructure device when the first mold component is removed from the microstructure device, the second mold component having a shape configured so that a second chamber is formed in the microstructure device when the second mold component is removed from the microstructure device.

24. The method of claim 23 wherein the first and second mold components are spaced at a distance when the device mold is assembled so that a flexible membrane is formed in the microstructure device between the first and second chambers when the first and second mold components are removed from the microstructure device.

25. The method of claim 21 wherein the set of mold components comprises a first elongated mold component and a second elongated mold component, the first elongated mold component having a diameter or dimension smaller than the second elongated mold component, the second elongated mold component having an opening which has same dimension as the cross section of the first elongated mold component, and assembling the device mold comprises inserting the first elongated mold component through the opening in the second elongated mold component to form an intersection.

26. The method of claim 21, wherein the set of mold components comprises an elongated mold component and a cylinder, the cylinder having a passageway with a dimension substantially the same as a dimension of the elongated mold component, and assembling the device mold comprises partially inserting the elongated mold component into the passageway.

27. The method of claim 21 wherein the set of mold components comprises a castable mold component and an elongated mold component, the castable mold component having a shape configured to form a cavity in the microstructure device, the elongated mold component having a shape configured to form a channel in the microstructure device, the castable mold component having a recess structure for receiving an end of the elongated mold component, the recess structure having means to prevent the castable mold component from moving relative to the elongated mold member when the device mold is assembled.

28. The method of claim 27 wherein the elongated mold component has a first end and a second end, the mold body having a side wall with a hole, wherein assembling the device mold comprises inserting the first end of the elongated mold component into the recess structure of the castable mold component, and inserting the second end of the elongated mold component through the hole of the side wall of the device mold.

29. The method of claim 27 wherein the set of mold components includes a castable mold component having a shape suitable for forming a cavity and an elongated mold component suitable for forming a channel connecting the cavity in the microstructure device, wherein assembling the device mold comprises inserting the elongated mold component through a hole positioned on a side wall of the mold body, the elongated mold component supporting and aligning the castable mold component at a predefined position relative to the mold body.

30. The method of claim 21 wherein the set of mold components comprises a post and a mold component, the post supporting the mold component at a predetermined position relative to the mold body when the device mold is assembled.

31. A method of fabricating a microstructure device, comprising:

fabricating a device mold by connecting a set of mold components and to mold body and connecting a set of functional components to the mold body;

casting the microstructure device from the device mold; and

removing the set of mold components from the microstructure device while retaining the functional components in the microstructure device.

32. The method of claim 31 wherein casting the microstructure device comprises pouring or injecting a liquid polymer into the device mold.

33. The method of claim 31 wherein the set of mold components comprises a castable mold component, the set of functional components comprises an electrode having a tip,

wherein fabricating the device mold comprises embedding a tip of the electrode into one of the castable mold components so that the tip of the electrode is surrounded by the castable mold component,

wherein removing the castable mold component from the microstructure device exposes the tip of the electrode to a cavity in the microstructure device.

34. The method of claim 31, wherein the set of mold components comprises an elongated mold component, the set of functional components comprises an electrode having a structure that defines a hole,

wherein fabricating the device mold comprises inserting the elongated mold component through the hole in the electrode.

35. The method of claim 31 wherein the set of mold components comprises a mold component that defines a conduit in the microstructure device, the method further comprising coating a surface of the conduit with a material having a refractive index lower than a refractive index of a liquid material used for filling the conduit.

36. An apparatus, comprising:

a microdevice body having a structure that defines a channel to allow passage of a fluid;

an electrical component to interact with a portion of the liquid, a portion of the electrical component being embedded in the microdevice body; and

an optical component to generate, transmit, or receive light that interacts with a portion of the liquid, a portion of the optical component being embedded in the microdevice body such that the microdevice body and the optical component and the electrical component form an integrated unit.

37. The apparatus of claim 36 in which the microdevice body is substantially made of polymer.

38. The apparatus of claim 36, further comprising a platform for supporting the electrical component and the optical component at predetermined positions.

39. The apparatus of claim 38, wherein the platform comprises a circuit board.

40. The apparatus of claim 36, further comprising a device mold for casting the microdevice body.

41. The apparatus of claim 36, further comprising a controller that is integrated with the microdevice body to control the electrical component.

42. The apparatus of claim 41 in which the structure of the microdevice body further defines a chamber connected to the channel, the electrical component comprising a heater integrated with the microdevice body for heating a liquid in the chamber, the heater being controlled by the controller.

43. The apparatus of claim 42 in which the microcontroller controls the heater to heat the liquid in the chamber according to a predefined protocol to facilitate a polymerase chain reaction.

44. The apparatus of claim 36 in which the optical component comprises an optical waveguide.

45. The apparatus of claim 36 in which the optical component comprises a photo sensor.

46. The apparatus of claim 36 in which the structure of the microdevice body further defines a chamber, and the apparatus further comprising a valve to open or close the channel, the valve comprising a diaphragm made of shape memory alloy.

47. The apparatus of claim 36 in which the structure of the microdevice body further defines a fluid inlet, a chamber, and an opening between the fluid inlet and the chamber, the fluid inlet having a shape such that a fluidic pressure in a direction from the inlet towards the chamber tends to cause the opening to remain open, whereas a fluidic pressure in a direction from the chamber towards the inlet tends to close the opening.

48. The apparatus of claim 36 in which the structure of the microdevice body further defines a fluid inlet and a chamber, the fluid inlet has a funnel shape that extends into the chamber, the fluid inlet and the chamber being separated by a flexible membrane having a funnel shape having a larger opening that tapers into a smaller opening that connects the fluid inlet to the chamber.

49. A microfluidic system comprising:

a microfluidic device having fluidic components; and

a cassette having interfaces for interfacing the fluidic components.

50. The apparatus of claim 49 in which the microfluidic device comprises pneumatic components.

51. The apparatus of claim 50, wherein the cassette comprises pneumatic interfaces configured to be coupled to the pneumatic components in the microfluidic device.

52. The apparatus of claim 50 in which the microfluidic device comprises electrical components.

53. The apparatus of claim 52, wherein the cassette further comprising electrical interfaces configured to be coupled to the electrical components in the microfluidic device.

54. An apparatus, comprising:

a device mold that includes a mold body, removable mold components, and functional components, the mold body and the removable mold components and the functional components being connected to define a space within the device mold for casting a microstructure device, the removable components comprising material that can be removed from the microstructure device after the microstructure device is cast, the functional components being integrated with the microstructure device after the microstructure device is cast.

55. The apparatus of claim 54 wherein the removable mold components comprise a first set of mold components and a second set of mold components,

the first set of mold component having shapes configured to form chambers when the first set of mold component are removed from the microstructure device,

the second set of mold components having shape configured to form channels when the second set of mold components are removed from the microstructure device,

the first and second sets of mold components being positioned relative to one another when connected to form the device mold such that the chambers and channels in combination form a component of a peristaltic pump.

56. The method of claim 54 wherein the mold body comprises a bottom wall and a side wall, the side wall defining a hole that is positioned at a predetermined distance from the bottom wall, the hole receiving an end of one of the removable mold components, the predetermined distance selected so that the removable mold component is disposed at a predefined position relative to the mold body within the device mold.