Polymer-based platform for microfluidic systems

• US 7,601,286 B2
• Filed: 03/26/2002
• Issued: 10/13/2009
• Est. Priority Date: 03/26/2001
• Status: Expired due to Fees

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Inventors: Maghribi, Mariam, Benett, William, Wang, Amy W., Rose, Klint, Krulevitch, Peter, Hamilton, Julie
• Primary Examiner(s): HUSON, MONICA ANNE
• Application Number:
  US10/107,933
• Publication Number:
  US 20020134907A1
• Time in Patent Office: 2,758 Days
• Field of Search: 264/334, 264/317, 264/221
• US Class Current: 264/221
• CPC Class Codes: B29C 33/3842 Manufacturing moulds, e.g. shaping the mould surface by machining
• 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: B29K 2083/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• CPC Class Codes: B29K 2083/005 LSR, i.e. liquid silicone rubbers, or derivatives thereof
• CPC Class Codes: B29L 2031/24 Pipe joints or couplings B29L2031/26 takes precedence
• CPC Class Codes: B29L 2031/756 Microarticles, nanoarticles

Abstract

A method of forming a polymer-based microfluidic system platform using network building blocks selected from a set of interconnectable network building blocks, such as wire, pins, blocks, and interconnects. The selected building blocks are interconnectably assembled and fixedly positioned in precise positions in a mold cavity of a mold frame to construct a three-dimensional model construction of a microfluidic flow path network preferably having meso-scale dimensions. A hardenable liquid, such as poly (dimethylsiloxane) is then introduced into the mold cavity and hardened to form a platform structure as well as to mold the microfluidic flow path network having channels, reservoirs and ports. Pre-fabricated elbows, T'"'"'s and other joints are used to interconnect various building block elements together. After hardening the liquid the building blocks are removed from the platform structure to make available the channels, cavities and ports within the platform structure. Microdevices may be embedded within the cast polymer-based platform, or bonded to the platform structure subsequent to molding, to create an integrated microfluidic system. In this manner, the new microfluidic platform is versatile and capable of quickly generating prototype systems, and could easily be adapted to a manufacturing setting.

Claims

1. A method of forming a microfluidic system platform comprising the steps of:

providing a mold frame having frame walls surrounding a mold cavity;

providing a set of independent mold forms for use in molding hollow microfluidic features, the set of independent mold forms comprising elongated mold forms for use in molding microfluidic channels, and block mold forms for use in molding microfluidic cavities;

constructing a three-dimensional model construction of a microfluidic flow path network in the mold cavity by interconnecting mold forms selected from the set of independent mold forms and suspending the model construction in the mold cavity via the frame walls;

introducing a hardenable liquid into the mold cavity to immerse the model construction thereby;

hardening the liquid to form (1) a platform structure having a shape of the mold cavity and (2) the microfluidic flow path network in the platform structure having a seamless shape of the model construction and including at least two access ports for enabling fluidic communication with the formed microfluidic flow path network; and

removing the model construction from the platform structure through the at least two access ports so as to avail the formed microfluidic flow path network.

2. The method as in claim 1,

wherein the hardenable liquid comprises a polymeric material.

3. The method as in claim 2,

wherein the polymeric material comprises an elastomeric silicone polymer.

4. The method as in claim 3,

wherein the silicone polymer comprises poly(dimethylsiloxane).

5. The method as in claim 1,

wherein the set of mold forms available for selection further comprises interconnect mold forms for interconnecting at least two of the elongated mold forms to each other.

6. The method as in claim 5,

wherein each of the interconnect mold forms have at least two connector ports in fluidic communication with each other, with each connector port adapted to seat an end portion of an elongated mold form therein.

7. The method as in claim 6,

wherein the removal of the model construction from the platform structure removes all selected mold forms except interconnect mold forms which remain embedded, whereby the fluidic flow path network is defined in part by the embedded interconnect mold forms.

8. The method as in claim 1,

wherein the construction of the model construction includes interconnecting a pre-formed microdevice to the model construction in the mold cavity so that, upon hardening the liquid and removing the model construction, the microdevice remains embedded in the platform structure as part of the microfluidic flow path network and in fluidic communication therewith.

9. The method as in claim 1,

wherein the model construction of the microfluidic flow path network has meso-scale dimensions.

10. The method as in claim 9,

wherein at least one of the frame walls has an inner surface having micro-scale topographical features facing the mold cavity, and

further comprising placing the meso-scale model construction in contact with the micro-scale topographical features so that, upon hardening the liquid and removing the model construction, the meso-scale microfluidic flow path network is in fluidic communication with micro-scale open cavities formed on a molded outer surface of the platform structure, whereby the meso-scale microfluidic flow path network serves to interface macro and micro-scale mediums.

11. The method as in claim 10,

further comprising bonding a substrate to the molded outer surface of the molded structure so as to enclose the micro-scale open cavities and thereby form a micro-scale microfluidic flow path network in fluidic communication with the meso-scale microfluidic flow path network.

12. The method as in claim 1,

wherein at least one of the access ports is a meso-scale reservoir cavity for receiving fluidic samples and formed from a block mold form placed in surface-to-surface contact with a frame wall.

13. The method as in claim 1,

wherein at least one of the access ports is a docking port adapted to captively seat a pre-formed microdevice so that fluidic communication may be established with the formed microfluidic flow path network.

14. A method of forming an integrated microfluidic system comprising the steps of:

providing a mold frame having frame walls surrounding a mold cavity;

providing a set of independent mold forms for use in molding hollow microfluidic features, the set of independent mold forms comprising elongated mold forms for use in molding microfluidic channels, and block mold forms for use in molding microfluidic cavities;

constructing a three-dimensional model construction of a microfluidic flow path network in the mold cavity by interconnecting mold forms selected from the set of independent mold forms and suspending the model construction in the mold cavity via the frame walls;

introducing a hardenable liquid into the mold cavity to immerse the model construction thereby;

hardening the liquid to form (1) a platform structure having a shape of the mold cavity and (2) the microfluidic flow path network in the platform structure having a seamless shape of the model construction and including at least two access ports for enabling fluidic communication with the formed microfluidic flow path network;

removing the model construction from the platform structure through the at least two access ports so as to avail the formed microfluidic flow path network; and

connecting a pre-formed microdevice to the platform structure so that fluidic communication is established with the formed microfluidic flow path network via at least one of the at least two access ports of the platform structure.

15. The method as in claim 14,

wherein the hardenable liquid comprises a polymeric material.

16. The method as in claim 15,

wherein the polymeric material comprises an elastomeric silicone polymer.

17. The method as in claim 16,

wherein the silicone polymer comprises poly(dimethylsiloxane).

18. The method as in claim 14,

wherein the construction of the model construction includes interconnecting a pre-formed microdevice to the selected mold forms in the mold cavity so that, upon hardening the liquid and removing the model construction, the microdevice remains embedded in the platform structure as part of the microfluidic flow path network and in fluidic communication therewith.

19. The method as in claim 14,

wherein the model construction of the microfluidic flow path network has meso-scale dimensions.

20. The method as in claim 19,

wherein at least one of the frame walls has an inner surface having micro-scale topographical features facing the mold cavity, and

further comprising placing the meso-scale model construction in contact with the micro-scale topographical features so that, upon hardening the liquid and removing the model construction, the meso-scale microfluidic flow path network is in fluidic communication with micro-scale open cavities formed on a molded outer surface of the platform structure, whereby the meso-scale microfluidic flow path network serves to interface macro and micro-scale mediums.

21. The method as in claim 20,

further comprising bonding a substrate to the molded outer surface of the molded structure so as to enclose the micro-scale open cavities and thereby form a micro-scale microfluidic flow path network in fluidic communication with the meso-scale microfluidic flow path network.

22. The method as in claim 14,

wherein the connection between the pre-formed microfludic device and the platform structure is effected by bonding the pre-formed microdevice to the platform structure.

23. The method as in claim 22,

wherein the pre-formed microdevice is bonded to the platform structure via oxidation bonding.

24. The method as in claim 14,

wherein at least one of the access ports is a docking port adapted to captively seat the pre-formed microdevice, and where the connection between the pre-formed microfluidic device and the platform structure comprises docking the pre-formed microdevice in the corresponding docking port of the platform structure to establish fluidic communication with the formed microfluidic flow path network.

25. The method as in claim 24,

wherein the pre-formed microdevice is releasably docked in the at least one docking port of the platform structure.

26. The method as in claim 14,

wherein at least one of the access ports is a meso-scale reservoir cavity for receiving fluidic samples and formed from a block mold form placed in surface-to-surface contact with a frame wall.

27. A method of forming a microfluidic system platform comprising the steps of:

providing a mold frame having frame walls surrounding a mold cavity, said frame walls having throughbores communicating with the mold cavity;

providing a set of mold forms for use in molding hollow microfluidic features, the set of mold forms comprising elongated mold forms for use in molding microfluidic channels, and block mold forms for use in molding microfluidic cavities;

constructing a three-dimensional model construction of a microfluidic flow path network in the mold cavity by interconnecting mold forms selected from the set of mold forms and suspending the model construction in the mold cavity via the frame walls by seating at least some of the selected mold forms in the throughbores;

introducing a hardenable liquid into the mold cavity to immerse the model construction thereby;

hardening the liquid to form (1) a platform structure having a shape of the mold cavity and (2) the microfluidic flow path network in the platform structure having a seamless shape of the model construction and including at least two access ports for enabling fluidic communication with the formed microfluidic flow path network; and

removing the model construction from the platform structure through the at least two access ports so as to avail the formed microfluidic flow path network.

28. The method as in claim 27,

wherein the removal of the model construction from the platform structure includes removing at least some of the selected mold forms through the throughbores.

29. The method as in claim 27,

further comprising connecting a pre-formed microdevice to the platform structure so that fluidic communication is established with the formed microfluidic flow path network via at least one of the at least two access ports of the platform structure.

30. The method as in claim 29,

wherein the removal of the model construction from the platform structure includes removing at least some of the selected mold forms through the throughbores.

31. The method as in claim 30,

wherein the set of mold forms available for selection further comprises interconnect mold forms for interconnecting at least two of the elongated mold forms to each other.

32. The method as in claim 31,

wherein each of the interconnect mold forms have at least two connector ports in fluidic communication with each other, with each connector port adapted to seat an end portion of an elongated mold form therein.

33. The method as in claim 32,

wherein the removal of the model construction from the platform structure removes all selected mold forms except interconnect mold forms which remain embedded, whereby the fluidic flow path network is defined in part by the embedded interconnect mold forms.