Microfluidic pump and valve structures and fabrication methods

• US 20060076068A1
• Filed: 10/03/2005
• Published: 04/13/2006
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: Rheonix, Inc.
• Original Assignee: Kionix Incorporated (ROHM Co., Ltd.)
• Inventors: Zhou, Peng, Young, Lincoln
• Granted Patent: US 7,832,429 B2
• Time in Patent Office: Days
• US Class Current: 137/829
• CPC Class Codes: B01F 2101/2202 Mixing compositions or mixers in the medical or veterinary field
• CPC Class Codes: B01F 25/451 characterised by means for moving the materials to be mixed or the mixture
• CPC Class Codes: B01F 25/4521 the components being pressed through orifices in elements, e.g. flat plates or cylinders, which obstruct the whole diameter of the tube
• CPC Class Codes: B01F 31/65 the materials to be mixed being directly submitted to a pulsating movement, e.g. by means of an oscillating piston or air column
• CPC Class Codes: B01F 33/30 Micromixers
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0861 Configuration of multiple channels and/or chambers in a single devices
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0481 squeezing of channels or chambers
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/06 Valves, specific forms thereof
• CPC Class Codes: B01L 2400/0638 membrane valves, flap valves
• CPC Class Codes: B01L 2400/0655 pinch valves
• CPC Class Codes: B01L 2400/084 Passive control of flow resistance
• 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 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B29C 65/4895 Solvent bonding, i.e. the surfaces of the parts to be joined being treated with solvents, swelling or softening agents, without adhesives
• CPC Class Codes: B29C 66/004 : Preventing sticking together, e.g. of some areas of the parts to be joined
• CPC Class Codes: B29C 66/54 : Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
• CPC Class Codes: B29C 66/5412 : said substantially flat extra element being flexible, e.g. a membrane B29C66/5416 takes precedence
• CPC Class Codes: B29C 66/71 : characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29K 2025/00 : Use of polymers of vinyl-aromatic compounds or derivatives thereof as moulding material
• CPC Class Codes: B29K 2025/04 : Polymers of styrene
• CPC Class Codes: B29K 2025/06 : PS, i.e. polystyrene
• CPC Class Codes: B29K 2033/08 : Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
• CPC Class Codes: B29K 2033/12 : Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2101/12 : Thermoplastic materials
• CPC Class Codes: B29L 2031/7496 : Pumps
• CPC Class Codes: B29L 2031/7506 : Valves
• CPC Class Codes: B29L 2031/756 : Microarticles, nanoarticles
• CPC Class Codes: B81B 2201/036 : Micropumps
• CPC Class Codes: B81B 2201/054 : Microvalves
• CPC Class Codes: B81B 2203/0127 : Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 3/0021 : Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81C 1/00103 : Structures having a predefined profile, e.g. sloped or rounded grooves
• CPC Class Codes: B81C 1/00158 : Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: F04B 43/028 : with in- or outlet valve arranged in the plate-like flexible member valve arranged in the piston F04B53/12
• CPC Class Codes: F04B 43/06 : Pumps having fluid drive
• CPC Class Codes: F15C 1/08 : Boundary-layer devices, e.g. wall-attachment amplifiers coanda effect fluid oscillators of pulse generators F15B21/12
• CPC Class Codes: F16K 2099/0074 : using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/0076 : using electrical discharge machining [EDM], milling or drilling
• CPC Class Codes: F16K 2099/0078 : using moulding or stamping
• CPC Class Codes: F16K 2099/008 : Multi-layer fabrications
• CPC Class Codes: F16K 2099/0084 : Chemistry or biology, e.g. "lab-on-a-chip" technology
• CPC Class Codes: F16K 2099/0094 : Micropumps
• CPC Class Codes: F16K 7/12 : with flat, dished, or bowl-shaped diaphragm
• CPC Class Codes: F16K 99/0001 : Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0015 : Diaphragm or membrane valves
• CPC Class Codes: F16K 99/0021 : No-moving-parts valves
• CPC Class Codes: F16K 99/0034 : Operating means specially adapted for microvalves
• CPC Class Codes: F16K 99/0055 : actuated by fluids
• CPC Class Codes: F16K 99/0057 : the fluid being the circulating fluid itself, e.g. check valves
• CPC Class Codes: F16K 99/0059 : actuated by a pilot fluid
• CPC Class Codes: Y10T 137/212 : System comprising plural fluidic devices or stages
• CPC Class Codes: Y10T 137/2202 : By movable element
• CPC Class Codes: Y10T 137/2218 : Means [e.g., valve] in control input
• CPC Class Codes: Y10T 137/8593 : Systems
• CPC Class Codes: Y10T 137/85978 : With pump
• CPC Class Codes: Y10T 156/1002 : with permanent bending or reshaping or surface deformation of self sustaining lamina
• CPC Class Codes: Y10T 156/1043 : Subsequent to assembly
• CPC Class Codes: Y10T 29/49405 : Valve or choke making

Abstract

Plastic microfluidic structures having a substantially rigid diaphragm that actuates between a relaxed state wherein the diaphragm sits against the surface of a substrate and an actuated state wherein the diaphragm is moved away from the substrate. As will be seen from the following description, the microfluidic structures formed with this diaphragm provide easy to manufacture and robust systems, as well readily made components such as valves and pumps.

Claims

1. A microfluidic device, comprising

a first rigid plastic substrate having upper and lower surfaces, and

a substantially rigid plastic membrane, contacting and joined with the upper surface of the first substrate, and having a relaxed state wherein the plastic membrane lies substantially against the upper surface of the first substrate and an actuated state wherein the membrane is moved away from the upper surface of the first substrate.

2. The device of claim 1, wherein

the first rigid plastic substrate has microfeatures formed therein, and the substantially rigid plastic membrane is disposed over the at least one microfeature.

3. The device of claim 2, wherein

the substantially rigid plastic membrane has a Young'"'"'s modulus of between about 2 Gpa and about 4 Gpa.

4. The device of claim 2, wherein

the membrane has a thickness selected for allowing deformation upon application of appropriate mechanical force.

5. The device of claim 4, wherein

the membrane has a thickness of between about 10 μ

m and about 150 μ

m.

6. The device of claim 4, wherein

the membrane has a thickness of between about 15 μ

m and about 75 μ

m.

7. The device of claim 4, wherein

the mechanical force is applied by a positive pressure to deform the membrane towards the substrate and is less than about 50 psi.

8. The device of claim 4, wherein

the mechanical force is applied by a negative pressure to deform the membrane away from the substrate and has a magnitude less than about 14 psi.

9. The device of claim 4, wherein

the mechanical force is applied by a positive pressure to deform the membrane towards the substrate and is between about 3 psi and about 25 psi.

10. The device of claim 4, wherein

the mechanical force is a negative pressure applied to deform the membrane away from the substrate and has a magnitude of between about 3 psi and about 14 psi.

11. The device of claim 1, wherein

the membrane and the first substrate are made from substantially a same material.

12. The device of claim 1, wherein

at least one of the membrane and the first substrate is a thermoplastic material.

13. The device of claim 1, wherein

at least one of the membrane and the first substrate is a linear polymeric material

14. The device of claim 1, wherein

at least one of the first substrate and the membrane are made from one of polymethyl methacrylate, polystyrene, polycarbonate, and acrylic.

15. The device of claim 2, wherein

the substantially rigid plastic membrane includes an unbonded region being unattached from the first substrate.

16. The device of claim 15, wherein

the unbonded region of the membrane at least partially overlies a first channel and a second channel disjoint from the first channel, both channels being disposed in the first substrate, and in the relaxed state forms a seal between the first and second channels.

17. The device of claim 16, wherein

the unbonded region of the membrane at least partially overlies a valve-seat formed in the first substrate, disconnected from and substantially between the first and second channels.

18. The device of claim 17, wherein

the valve seat comprises a ridge substantially perpendicular to a longitudinal axis of the first and second channels.

19. The device of claim 15, wherein

the unbonded region of the membrane at least partially overlies a first channel and a second channel disjoint from the first channel, both channels being disposed in the first substrate, and in the actuated state separates from the upper surface of the first substrate to provide a cavity suitable for fluid flow between the first and second channels.

20. The device of claim 15, wherein

the first substrate includes a through-hole extending from the upper surface of the first substrate to the lower surface of the first substrate.

21. The device of claim 15, wherein

the unbonded region of the membrane is substantially circular.

22. The device of claim 15, wherein

the unbonded region of the membrane is substantially elliptical.

23. The device of claim 15, wherein

the unbonded region of the membrane is substantially rectangular, with rounded corners.

24. The device of claim 15, further comprising

a second rigid plastic substrate contacting and joined with an upper surface of the membrane.

25. The device of claim 24 wherein

the first substrate, the second substrate, and the membrane are made of substantially a same material.

26. The device of claim 24, wherein

the second substrate includes a chamber lying substantially above the unbonded region of the membrane and sized such that the unbonded region of the membrane can be moved away from the upper surface of the first substrate and remain substantially enclosed by the chamber.

27. The device of claim 15, further comprising

a pump having a plurality of disconnected unbonded regions, each forming an independently actuatable valve structure and being connected in series by microchannels.

28. The device of claim 27, wherein

the microchannels have varying resistances to fluid flow.

29. The device of claim 27, further comprising

a supporting structure above the membrane sized, shaped, and positioned to structurally support the membrane when the membrane is in an actuated state.

30. The device of claim 27, further comprising

a stop disposed above the membrane sized, shaped, and positioned to prevent the membrane from moving beyond a distance from the first substrate.

31. The device of claim 27, comprising

a plurality of pumps having a shared valve structure.

32. The device of claim 31, wherein

the shared valve structure includes a membrane disposed above three or more microchannels to provide a plurality of fluid ports coupled with the shared valve.

33. The device of claim 27, further comprising

a reservoir capable of storing one or more of a fluid material, a gaseous material, a solid material that is substantially dissolved in a fluid material, a slurry material, an emulsion material, and a fluid material with particles suspended therein.

34. The device of claim 33, wherein

the reservoir is arranged to be substantially vertical, and can be coupled with liquid extraction means for extracting liquid from within the reservoir at or near defined vertical levels.

35. The device of claim 33, wherein

the reservoir is arranged to be substantially vertical and contains a fluid material and particles, and the pump is coupled to the reservoir so as to circulate fluid through the device in a manner that prevents the particles from settling at either of a top and a bottom of the reservoir.

36. The device of claim 27, wherein

the reservoir couples between a first and a second one of the independently actuatable valve structure.

37. The device of claim 33, further comprising

a plurality of reservoirs interconnected through a pump mechanism.

38. The device of claim 37, wherein

the pump mechanism includes a shared valve structure for passing fluid from the plurality of reservoirs.

39. The device of claim 27, wherein

at least one microfeature comprises a channel having a geometry for favoring one direction of flow.

40. The device of claim 15, further comprising

a pump having one unbonded region forming an externally actuatable diaphragm structure, interconnected by microchannels to two unbonded regions forming passive valve structures actuatable by fluid flowing through the pump.

41. The device of claim 15, further comprising

a pump having a plurality of disconnected unbonded regions, each forming an independently actuatable diaphragm structure, with each diaphragm structure partially overlapping at least one other diaphragm structure.

42. A microfluidic device, comprising

a first polystyrene substrate having upper and lower surfaces and microfeatures formed therein, and

a polystyrene membrane solvent bonded to the upper surface of the first substrate, and having a relaxed state wherein the polystyrene membrane lies substantially against the upper surface of the first substrate and an actuated state wherein the polystyrene membrane is moved away from the upper surface of the first substrate.

43. The device of claim 42 wherein

the solvent bond is formed by a solvent having little or substantially no bonding effect under room temperature and ambient force conditions, but capable of forming a bonded interface between two mating surfaces under appropriate temperature or force conditions.

44. A microfluidic system, comprising

a reservoir of the type capable of storing at least one of a fluid material, a gaseous material, a solid material substantially dissolved in a liquid material, an emulsion material, a slurry material, and a fluid material with particles suspended therein,

a reservoir pump chamber coupled to the reservoir and being connected to at least two other pump chambers, and

a controller capable of sequentially activating the reservoir pump chamber and the two other pump chambers, whereby a material is drawn into the reservoir pump chamber and then partially drawn into respective ones of the two pump chambers and the partially drawn material in one of the two pump chambers may be subsequently returned to the reservoir pump chamber.

45. The system of claim 44, wherein

the material comprises biological material.