WO2021221659A1 - Fabrication of multi-layer microfluidic systems - Google Patents

Fabrication of multi-layer microfluidic systems Download PDF

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Publication number
WO2021221659A1
WO2021221659A1 PCT/US2020/030718 US2020030718W WO2021221659A1 WO 2021221659 A1 WO2021221659 A1 WO 2021221659A1 US 2020030718 W US2020030718 W US 2020030718W WO 2021221659 A1 WO2021221659 A1 WO 2021221659A1
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WO
WIPO (PCT)
Prior art keywords
layer
opening
wax
chamber
over
Prior art date
Application number
PCT/US2020/030718
Other languages
French (fr)
Inventor
Alexander Govyadinov
Viktor Shkolnikov
Original Assignee
Hewlett-Packard Development Company, L.P.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett-Packard Development Company, L.P. filed Critical Hewlett-Packard Development Company, L.P.
Priority to PCT/US2020/030718 priority Critical patent/WO2021221659A1/en
Publication of WO2021221659A1 publication Critical patent/WO2021221659A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M23/00—Constructional details, e.g. recesses, hinges
    • C12M23/02—Form or structure of the vessel
    • C12M23/16—Microfluidic devices; Capillary tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/502707—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the manufacture of the container or its components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0887—Laminated structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00—Moving or stopping fluids
    • B01L2400/04—Moving fluids with specific forces or mechanical means
    • B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
    • B01L2400/0442—Moving fluids with specific forces or mechanical means specific forces thermal energy, e.g. vaporisation, bubble jet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/502761—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules

Definitions

  • Microfluidic systems can be used for a variety of applications. Some examples may include using microfluidic systems to study cells. For example, cells can be inserted into a microfluidic system to be manipulated, sorted, and transported to various storage areas of the system for further analysis. Microfluidic systems may enable a system of dense interconnects of small size and complicated networks suitable for use in end-to-end integrated microfluidic functional systems. Cell transfections, blood cell sorting, separation and concentration, rear cell sensing, isolation and analysis, sample preparation, and the like are a few example applications that can use microfluidic systems.
  • FIG. 1 illustrates a block diagram of an example multi-layer microfluidic system that can be fabricated using the processes of the present disclosure
  • FIG. 2A-2B is a process-flow diagram of an example method for fabricating a multi-layer microfluidic system of the present disclosure
  • FIG. 3A-3B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure
  • FIG. 4A-4B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure
  • FIG. 5A-5B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure
  • FIG. 6A-6B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure.
  • microfluidic systems can be used for a variety of different applications. Fabrication of the micro-fluidic channels may not be trivial. Most microfluidic systems comprise a single layer. As a result, to increase the size of a system, the footprint of the microfluidic channel may increase considerably.
  • microfluidic devices are planar (e.g., a single layer). Microfluidic devices with multiple channels may be spread across the substrate and may have relatively large footprints. Some multi-layer fluidic channels with active substrate are overly complicated to manufacture or have channels that are too large (e.g., hybrid microfluidic channels with fabricated with polymers). Other multi-channel microfluidic channels may be passive with pneumatically driven chips. The passive systems do not include active substrates and include complicated pneumatic control systems.
  • the present disclosure provides a relatively low cost fabrication method that creates a multi-layer microfluidic system with a relatively small channel cross-section to reduce an amount of sample and reagent that is used, as well as decreasing the overall assay time.
  • Examples herein provide methods for fabricating multi-layer microfluidic systems that can be used for direct injection of reagents into a cell.
  • the methods fabricate the multi-layer microfluidic system with active substrates and multiple layers of channels along a z-axis (e.g., vertical direction).
  • the methods described herein allow well defined openings to be created despite high aspect ratio features in the multi-layer microfluidic systems of the present disclosure.
  • FIG. 1 illustrates a cross-sectional block diagram of an example multi layer microfluidic system 100 of the present disclosure.
  • the multi-layer microfluidic system 100 may include a reagent chamber 102, a synthetic jet channel 104, and a channel 106.
  • Cells 112i to 112 n (hereinafter also referred to individually as a cell 112 or collectively as cells 112) are fed towards the synthetic jet channel 104 through the channel 106.
  • the cells 112 may be moved through the channel 106 via a pump (not shown), gravity, capillary force, centrifugal force, electrophoretic force, dielectrophoretic force, and the like.
  • the sizing of the channel 106 may be a function of the size of the cell 112.
  • the sizing may refer to the dimensions (e.g., length and width) of the cross-sectional opening of the channel 106.
  • the size of the channel 106 may be large enough to allow the passage of a single cell 112 at a time.
  • the synthetic jet channel 104 may comprise a volume located between an opening of the reagent chamber 102 and an opening in the channel 106.
  • the synthetic jet channel 104 may include an energy source 108 to heat a liquid in the synthetic jet channel 104 to generate a synthetic jet 110.
  • the synthetic jet 110 may move at a velocity sufficient to carry a reagent 114 in the synthetic jet channel 104 towards the cell 112.
  • a cell may be positioned adjacent to the synthetic jet channel 104 and the energy source 108 to receive the reagent 114.
  • the synthetic jet 110 may porate the cell 112 2 to allow the reagent 114 to be injected into the cell 112 2 .
  • the term “injection” may include the action of poration of the cell and insertion of the reagent 114.
  • the synthetic jet 110 may also move the reagent 114 towards the cell 112 2 to inject the reagent 114 into the cell 112 2 .
  • the synthetic jet 110 may be defined as a jet of the same fluid as the surrounding fluid (e.g., a jet of air formed within air or a jet of water formed within water).
  • the synthetic jet 110 may be formed as a jet of a liquid created within the liquid in the synthetic jet channel 104.
  • the synthetic jet 110 is formed from the surrounding liquid rather than an external source or fluid.
  • the liquid may be water, a solvent, or any other liquid that is compatible with the reagent 114 and the cells 112.
  • the synthetic jet 110 may be formed by the energy source 108.
  • the energy source 108 may locally heat the liquid in the synthetic jet channel 104 to create vapor bubbles of the liquid. As the vapor bubbles burst, the energy released by the bursting vapor bubbles may create the synthetic jet 110.
  • the synthetic jet 110 may move in a direction of the bursting vapor bubbles.
  • the energy source 108 may be arranged to direct the synthetic jet 110 towards an opening of the synthetic jet channel 104 where a cell 112 is located to receive the reagent 114.
  • the energy source 108 may be an inductive heater or a resistor heater.
  • An example of a resistor heater may be a thermal inkjet (TIJ) resistor.
  • TIJ resistor may include a controllable circuit that includes a resistor heater. When the circuit is activated, current may flow through the resistor heater to generate heat.
  • the multi-layer microfluidic system 100 may be connected to additional components that are not shown.
  • the multi-layer microfluidic system 100 may include a cell source, a collector, and a controller.
  • the controller may control operation of various devices (e.g., the energy source 108).
  • the cells 112 may be fed to a collector for further sorting and/or analysis.
  • the collector may be a collection apparatus such as a container, individual wells of a well array, and the like.
  • the collector may form a continuous loop.
  • the cells 112 may travel from the collector back to the cell source.
  • some cells 112 may not be injected when fed through the multi-layer microfluidic system 100.
  • some cells 112 may be collected in the collector and other cells 112 may be fed back to the cell source to form a loop.
  • FIG.1 illustrates an example the multi-layered microfluidic system 100.
  • the multi-layered fluidic system 100 may be varied with additional features (e.g., a trapping notch, additional chambers, additional vertical layers, in-situ cell sorting, and the like).
  • the additional layers may be built along a z-axis 116, shown in FIG. 1.
  • FIGs. 2A-2B, 3A-3B, 4A-4B, 5A-5B, and 6A-6B illustrate process-flow diagrams of different methods for fabricating the multi-layered microfluidic system 100, as well as other variations of the multi-layered microfluidic system 100.
  • the methods illustrated in FIGs. 2A-2B, 3A-3B, 4A-4B, 5A-5B, and 6A-6B may be performed by various tools in a fabrication plant.
  • the tools may be controlled by a central controller or processor.
  • each layer may be grown or deposited using existing fabrication techniques, unless otherwise noted.
  • the layers described in the FIGs. 2 A-2B, 3A-3B, 4A-4B, 5A-5B, and 6A-6B may be deposited via sputtering, thermally grown, mechanically spun on, and so forth.
  • each layer may be chemically and/or mechanically polished to provide a smooth flat surface to receive a subsequent layer.
  • FIGs. 2A-2B illustrate a method 200 for fabricating a multi-layered microfluidic system 280.
  • the method 200 may provide a substrate 250.
  • the substrate 250 may be an active substrate that is electrically functional.
  • the substrate 250 may be silicon (Si), a complementary metal oxide semiconductor (CMOS), a printed circuit board (PCB), and the like.
  • the substrate 250 may include an energy source 253.
  • the energy source 253 may be formed in the substrate 250 or electrically coupled to the substrate 250.
  • the energy source 253 may be a TIJ resistor similar to the energy source 108 illustrated in FIG. 1 , and described above.
  • a primer layer 252 may be deposited onto the substrate 250.
  • the primer layer 252 may be a photo-definable material or polymer (e.g., SU8).
  • a trench 256 may be etched in the primer layer 252.
  • the trench 256 may be located over the energy source 253. For example, the trench 256 may expose a portion of the substrate 250 that includes the energy source 253.
  • the method 200 may deposit a chamber layer 254.
  • the chamber layer 254 may be formed from a photo-definable material or polymer (e.g., SU8).
  • the trench 256 may be etched and extended through the chamber layer 254.
  • the trench 256 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, as illustrated in FIG. 1 , and discussed above.
  • the method 200 may fill the trench 256 with a sacrificial wax 258.
  • the wax 258 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers).
  • the wax 258 may have a low molecular weight.
  • the process performed at block 206 may also be referred to as a lost wax method.
  • an intermediate layer 260 may be deposited onto the chamber layer 254 and the wax 258.
  • the intermediate layer 260 may be a photo-definable material or polymer (e.g., SU8).
  • a photolithography process may be carried out to form an opening or bore 262 in the intermediate layer 260.
  • the opening 262 may be located over the wax 258.
  • the opening 262 may be formed to expose a portion of the wax 258.
  • the opening 262 may be aligned with the energy source 253.
  • the photolithography process may include providing a mask or pattern over the intermediate layer 260.
  • An energy source or light e.g., ultra violet (UV) light may be directed over the mask to expose those portions of the intermediate layer 260 that are not covered by the mask (e.g., the portion where the opening 262 is formed).
  • the intermediate layer 260 may be baked or heated after exposure.
  • the intermediate layer 260 may then be etched to remove the portions of the intermediate layer 260 that were exposed to the energy source.
  • the mask may then be etched away.
  • the method 200 may fill the opening 262 with the wax 258.
  • Using photolithography to form the opening 262 and then filling the opening 262 with the wax 258 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 262 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
  • the method 200 may deposit a transport layer 264 over the intermediate layer 260 and the wax 258.
  • the transport layer 264 may be a photo-definable material or polymer (e.g., SU8).
  • the thickness of the transport layer 264 may be a function of a size of the cells 112.
  • the transport layer 264 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
  • an opening 266 may be etched into the substrate 250.
  • the opening 266 may be located over a portion of the wax 258.
  • the opening 266 in the substrate 250 may expose a portion of the wax 258.
  • the opening 266 may be on an opposite end of the wax 258 as the opening 262 that was formed in block 208 of the method 200.
  • the opening 266 may also be formed in the substrate 250 in a portion that is over the wax 258 and adjacent to the energy source 253.
  • a microfluidic channel 268 may be formed in the transport layer 264.
  • the microfluidic channel 268 may be formed over the wax 258.
  • the microfluidic channel 268 may formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1) through the microfluidic channel 268.
  • the microfluidic channel 268 may be formed via a photolithography process. In another example, the microfluidic channel 268 may be formed via laser ablation. In another example, the microfluidic channel 268 may be pre-patterned into the transport layer 264. The pre-patterned transport layer 264 may then be laminated onto the intermediate layer 260.
  • the method 200 may remove the wax 258 from the trench 256 and the opening 262.
  • the wax 258 may be removed via a solvent as noted above.
  • a top hat layer 270 may be deposited over the transport layer 264 and the microfluidic channel 268.
  • the top hat layer 270 may also be a photo-definable material or polymer (e.g., SU8).
  • a chamber 272 may be coupled to the substrate 250 over the opening 266.
  • the chamber 272 may be, for example, the reagent chamber 102 illustrated in FIG. 1 .
  • the multi layered microfluidic system 280 may be completed.
  • FIGs. 3A-3B illustrate a method 300 for fabricating a multi-layered microfluidic system 380.
  • the method 300 may provide a substrate 350.
  • the substrate 350 may be an active substrate that is electrically functional.
  • the substrate 350 may be Si, a CMOS, a PCB, and the like.
  • the substrate 350 may include an energy source 353.
  • the energy source 353 may be formed in the substrate 350 or electrically coupled to the substrate 350.
  • the energy source 353 may be a TIJ resistor similar to the energy source 108 illustrated in FIG. 1 , and described above.
  • a primer layer 352 may be deposited onto the substrate 350.
  • the primer layer 352 may be a photo-definable material or polymer (e.g., SU8).
  • a trench 356 may be etched in the primer layer 352.
  • the trench 356 may be located over the energy source 353.
  • the trench 356 may expose a portion of the substrate 350 that includes the energy source 353.
  • the method 300 may deposit a chamber layer 354.
  • the chamber layer 354 may be formed from a photo-definable material or polymer (e.g., SU8).
  • the trench 356 may be etched and extended through the chamber layer 354.
  • the trench 356 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, illustrated in FIG. 1 , and discussed above.
  • the method 300 may fill the trench 356 with a sacrificial wax 358.
  • the wax 358 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers).
  • the wax 358 may have a low molecular weight.
  • the process performed at block 306 may also be referred to as a lost wax method.
  • an intermediate layer 360 may be deposited onto the chamber layer 354 and the wax 358.
  • the intermediate layer 360 may be a photo-definable material or polymer (e.g., SU8).
  • a photolithography process as described above, may be carried out to form an opening or bore 362 in the intermediate layer 360.
  • the opening 362 may be located over the wax 358.
  • the opening 362 may be formed to expose a portion of the wax 358.
  • the opening 362 may be aligned with the energy source 353.
  • the method 300 may fill the opening 362 with the wax 358. Using photolithography to form the opening 362 and then filling the opening 362 with the wax 358 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 362 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1. [0046] At block 312, the method 300 may deposit a trapping layer 362 over the intermediate layer 360.
  • the trapping layer 362 may be a photo-definable material or polymer (e.g., SU8).
  • the method 300 may etch a trench 364 over the opening 362.
  • the size of the trench 364 may be in accordance with the size of the cells 112.
  • the trench 364 may be formed to be large enough to trap a single cell 112.
  • the trench 364 may then be filled with the wax 358.
  • the trench 364 may be formed below the energy source 363 and over the opening 362 such that a cell 112 may be temporarily held in place under the energy source 363 to be transfected with the reagent 114, as described above.
  • the method 300 may deposit a transport layer 366 over the trapping layer 362 and the wax 358.
  • the transport layer 366 may be a photo-definable material or polymer (e.g., SU8).
  • the thickness of the transport layer 366 may be a function of a size of the cells 112.
  • the transport layer 366 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
  • an opening 368 may be etched into the substrate 350.
  • the opening 368 may be located over a portion of the wax 358.
  • the opening 368 in the substrate 350 may expose a portion of the wax 358.
  • the opening 368 may be on an opposite end of the wax 358 from the opening 362 that was formed in block 308 of the method 300.
  • the opening 368 may also be formed in the substrate 350 in a portion that is over the wax 358 and adjacent to the energy source 353.
  • a microfluidic channel 370 may be formed in the transport layer 366.
  • the microfluidic channel 370 may be formed over the wax 358.
  • the microfluidic channel 370 may be formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1) through the microfluidic channel 370.
  • the microfluidic channel 370 may be formed via a photolithography process. In another example, the microfluidic channel 370 may be formed via laser ablation. In another example, the microfluidic channel 370 may be pre-patterned into the transport layer 366. The pre-patterned transport layer 366 may then be laminated onto the trapping layer 362.
  • the method 300 may remove the wax 358 from the trench 356, the opening 362, and the trench 364.
  • the wax 358 may be removed via a solvent as noted above.
  • a top hat layer 372 may be deposited over the transport layer 366 and the microfluidic channel 370.
  • the top hat layer 372 may also be a photo-definable material or polymer (e.g., SU8).
  • a chamber 374 may be coupled to the substrate 350 over the opening 368.
  • the chamber 374 may be, for example, the reagent chamber 102 illustrated in FIG. 1.
  • the multi layered microfluidic system 380 may be completed.
  • FIGs. 4A-4B illustrate a method 400 for fabricating a multi-layered microfluidic system 480.
  • the method 400 may provide a substrate 450.
  • the substrate 450 may be an active substrate that is electrically functional.
  • the substrate 450 may be Si, a CMOS, a PCB, and the like.
  • the substrate 450 may include an energy source 453.
  • the energy source 453 may be formed in the substrate 450 or electrically coupled to the substrate 450.
  • the energy source 453 may be a TIJ resistor similar to the energy source 108 illustrated in FIG. 1 , and described above.
  • a primer layer 452 may be deposited onto the substrate 450.
  • the primer layer 452 may be a photo-definable material or polymer (e.g., SU8).
  • a trench 456 may be etched in the primer layer 452.
  • the trench 456 may be located over the energy source 453.
  • the trench 456 may expose a portion of the substrate 450 that includes the energy source 453.
  • the method 400 may deposit a chamber layer 454.
  • the chamber layer 454 may be formed from a photo-definable material or polymer (e.g., SU8).
  • the trench 456 may be etched and extended through the chamber layer 454.
  • the trench 456 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, illustrated in FIG. 1 , and discussed above.
  • the method 400 may fill the trench 456 with a sacrificial wax 458.
  • the wax 458 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers).
  • the wax 458 may have a low molecular weight.
  • the process performed at block 406 may also be referred to as a lost wax method.
  • an intermediate layer 460 may be deposited onto the chamber layer 454 and the wax 458.
  • the intermediate layer 460 may be a photo-definable material or polymer (e.g., SU8).
  • a photolithography process as described above, may be carried out to form an opening or bore 462 in the intermediate layer 460.
  • the opening 462 may be located over the wax 458.
  • the opening 462 may be formed to expose a portion of the wax 458.
  • the opening 462 may be aligned with the energy source 453.
  • the method 400 may fill the opening 462 with the wax 458.
  • Using photolithography to form the opening 462 and then filling the opening 462 with the wax 458 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 462 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
  • the method 400 may deposit a transport layer 464 over the intermediate layer 454 and the wax 458.
  • the transport layer 464 may be a photo-definable material or polymer (e.g., SU8).
  • the thickness of the transport layer 464 may be a function of a size of the cells 112.
  • the transport layer 464 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
  • a microfluidic channel 466 may be formed in the transport layer 464.
  • the microfluidic channel 466 may be formed over the wax 458.
  • the microfluidic channel 466 may be formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1) through the microfluidic channel 466.
  • the microfluidic channel 466 may be formed via a photolithography process. In another example, the microfluidic channel 466 may be formed via laser ablation. In another example, the microfluidic channel 466 may be pre-patterned into the transport layer 464. The pre-patterned transport layer 464 may then be laminated onto the intermediate layer 460.
  • the method 400 may etch an opening 468 into the substrate 450.
  • the opening 468 may be located over a portion of the wax 458.
  • the opening 468 in the substrate 450 may expose a portion of the wax 458.
  • the opening 468 may be on an opposite end of the wax 458 from the opening 462 that was formed in block 408 of the method 400.
  • the opening 468 may also be formed in the substrate 450 in a portion that is over the wax 458 and adjacent to the energy source 453.
  • the method 400 may remove the wax 458 from the trench 456 and the opening 462.
  • the wax 458 may be removed via a solvent as noted above.
  • the method 400 may deposit a trapping layer 470 over the transport layer 464.
  • the trapping layer 470 may be a photo-definable material or polymer (e.g., SU8).
  • the trapping layer 470 may include an opening 472 located below the opening 462 and the energy source 453.
  • the opening 472 may be sized to be large enough to trap a single cell 112.
  • the opening 472 may be formed below the energy source 453 and over the opening 462 such that a cell 112 may be temporarily held in place under the energy source 453 to be transfected with the reagent 114, as described above.
  • the opening 472 in the trapping layer 470 may be formed via a photolithography process. In another example, the opening 472 in the trapping layer 470 may be formed via laser ablation. In another example, the opening 472 in the trapping layer 470 may be pre-patterned into the trapping layer 470. The pre-patterned trapping layer 470 may then be laminated onto the intermediate layer 460.
  • a top hat layer 474 may be applied over the trapping layer 470.
  • the top hat layer 474 may also be a photo-definable material or polymer (e.g., SU8).
  • FIGs. 5A-5B illustrate a method 500 for fabricating a multi-layered microfluidic system 580.
  • the method 500 may provide a substrate 550.
  • the substrate 550 may be an active substrate that is electrically functional.
  • the substrate 550 may be Si, a CMOS, a PCB, and the like.
  • the substrate 550 may include multiple energy sources 553i and 553 2 .
  • the energy sources 553i and 553 2 may be formed in the substrate 550 or electrically coupled to the substrate 550.
  • the energy sources 553i and 553 2 may be TIJ resistors similar to the energy source 108 illustrated in FIG. 1 , and described above.
  • the energy source 553i may be used to create a synthetic jet 110 and transfect the cells 112 with the reagent 114.
  • the energy source 553 2 may be used as a microfluidic pump to move the cells 112 within the different layers of the multi-layered microfluidic system 580.
  • a primer layer 552 may be deposited onto the substrate 550.
  • the primer layer 552 may be a photo-definable material or polymer (e.g., SU8).
  • Trenches 556 may be etched in the primer layer 552.
  • the trenches 556 may be located over the energy sources 553i and 553 2 .
  • the trenches 556 may expose portions of the substrate 550 that include the energy sources 553i and 553 2 .
  • the method 500 may deposit a chamber layer 554.
  • the chamber layer 554 may be formed from a photo-definable material or polymer (e.g., SU8).
  • the trenches 556 may be etched and extended through the chamber layer 554.
  • One of the trenches 556 below the energy source 553i may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, as illustrated in FIG. 1 , and discussed above.
  • the other trench 556 may be located over the energy source 553 2 to collect the transfected cells 112 and move the cells 112 to another layer via the energy source 553 2 .
  • the method 500 may fill the trenches 556 with a sacrificial wax 558.
  • the wax 558 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers).
  • the wax 558 may have a low molecular weight.
  • the process performed at block 506 may also be referred to as a lost wax method.
  • an intermediate layer 560 may be deposited onto the chamber layer 554 and the wax 558.
  • the intermediate layer 560 may be a photo-definable material or polymer (e.g., SU8).
  • a photolithography process as described above, may be carried out to form an opening or bore 562 in the intermediate layer 560.
  • the openings 562 may be located over the wax 558.
  • the openings 562 may be formed to expose a portion of the wax 558.
  • the openings 562 may be aligned with the energy sources 553i and 553 2 .
  • the openings 562 may then be filled with the wax 558.
  • Using photolithography to form the openings 562 and then filling the openings 562 with the wax 558 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the openings 562 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
  • the method 500 may deposit a transport layer 564 over the intermediate layer 554 and the wax 558.
  • the transport layer 564 may be a photo-definable material or polymer (e.g., SU8).
  • the thickness of the transport layer 564 may be a function of a size of the cells 112.
  • the transport layer 564 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
  • the method 500 may form a microfluidic channel 566 in the transport layer 564.
  • the microfluidic channel 566 may be formed over the wax 558.
  • the microfluidic channel 566 may be formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1 ) through the microfluidic channel 566.
  • the microfluidic channel 566 may be formed via a photolithography process. In another example, the microfluidic channel 566 may be formed via laser ablation. In another example, the microfluidic channel 566 may be pre-patterned into the transport layer 564. The pre-patterned transport layer 564 may then be laminated onto the intermediate layer 560.
  • an opening 568 may be etched into the substrate 550.
  • the opening 568 may be located over a portion of the wax 558 that fills the trench 556 that includes the energy source 553i.
  • the opening 568 may be on an opposite end of the wax 558 from the opening 562 that was formed in the trench 556 that includes the energy source 553i.
  • the method 500 may remove the wax 558 from the trenches 556 and the openings 562.
  • the wax 558 may be removed via a solvent as noted above.
  • a top hat layer 570 may be formed over the transport layer 564.
  • the top hat layer 570 may also be a photo-definable material or polymer (e.g., SU8).
  • the method 500 may create an opening 574 in the top hat layer 570.
  • the opening 574 may be connected to an external collector, another chamber or channel of another multi-layered microfluidic system, and the like.
  • the opening 574 may be formed via laser ablation or may be pre patterned into the top hat layer 570 before the top hat layer 570 is laminated onto the transport layer 564
  • a chamber 572 may be coupled to the substrate 550 over the opening 568.
  • the chamber 572 may be, for example, the reagent chamber 102 illustrated in FIG. 1.
  • the multi-layered microfluidic system 580 may be completed.
  • FIGs. 6A-6B illustrate a method 600 for fabricating a multi-layered microfluidic system 680.
  • the method 600 may provide a substrate 650.
  • the substrate 650 may be an active substrate that is electrically functional.
  • the substrate 650 may be Si, a CMOS, a PCB, and the like.
  • the substrate 650 may include multiple energy sources 653i, 653 2 , 653 3 , and 653 4 .
  • the energy sources 653i, 653 2 , 653 3 , and 653 4 may be formed in the substrate 650 or electrically coupled to the substrate 650.
  • the energy sources 653i, 653 2 , 653 3 , and 653 4 may be TIJ resistors similar to the energy source 108 illustrated in FIG. 1 , and described above.
  • the energy source 653 3 may be used to create a synthetic jet 110 and transfect the cells 112 with the reagent 114.
  • the energy sources 653i, 653 2 , and 653 4 may be used as microfluidic pumps to move the cells 112 within the different layers of the multi-layered microfluidic system 680.
  • a primer layer 652 may be deposited onto the substrate 650.
  • the primer layer 652 may be a photo-definable material or polymer (e.g., SU8).
  • Trenches 656 may be etched in the primer layer 652.
  • the trenches 656 may be located over the energy sources 653i, 653 2 , 653 3 , and 653 4 .
  • the trenches 656 may expose portions of the substrate 650 that include the energy sources 653i, 653 2 , 653 3 , and 653 4 .
  • the method 600 may deposit a chamber layer 654.
  • the chamber layer 654 may be formed from a photo-definable material or polymer (e.g., SU8).
  • the trenches 656 may be etched and extended through the chamber layer 654.
  • One of the trenches 656 below the energy source 553 3 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, illustrated in FIG. 1 , and discussed above.
  • the other trenches 556 may be located over the energy source 653i, 653 2 , and 653 4 to collect the transfected cells 112 and move the cells 112 to another layer or chamber within the multi-layered microfluidic system 680.
  • the method 600 may fill the trenches 656 with a sacrificial wax 658.
  • the wax 658 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers).
  • the wax 658 may have a low molecular weight.
  • the process performed at block 606 may also be referred to as a lost wax method.
  • an intermediate layer 660 may be deposited onto the chamber layer 654 and the wax 658.
  • the intermediate layer 660 may be a photo-definable material or polymer (e.g., SU8).
  • a photolithography process as described above, may be carried out to form openings or bores 662 in the intermediate layer 660.
  • the openings 662 may be located over the wax 658.
  • the openings 662 may be formed to expose a portion of the wax 658.
  • the openings 662 may be aligned with the energy sources 653i, 653 2 , 653 3 , and 653 4 .
  • the openings 662 may be filled with the wax 658.
  • Using photolithography to form the openings 662 and then filling the opening 662 with the wax 658 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 662 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
  • the method 600 may deposit a transport layer 664 over the intermediate layer 654 and the wax 658.
  • the transport layer 664 may be a photo-definable material or polymer (e.g., SU8).
  • the thickness of the transport layer 664 may be a function of a size of the cells 112.
  • the transport layer 664 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
  • a microfluidic channel 666 may be formed in the transport layer 664.
  • the microfluidic channel 666 may be formed over the wax 658.
  • the microfluidic channel 666 may be formed via a photolithography process.
  • the microfluidic channel 666 may be formed via laser ablation.
  • the microfluidic channel 666 may be pre patterned into the transport layer 664. The pre-patterned transport layer 664 may then be laminated onto the intermediate layer 660.
  • the method 600 may etch openings 668 into the substrate 650.
  • the openings 668 may be located over a portion of the wax 658 that fills the trench 656 that includes the respective energy sources 653i, 653 2 , 653 3 , and 653 4 .
  • the openings 568 may be formed on an opposite end of the wax 658 from the openings 662 that were formed in the trenches 656.
  • the method 600 may remove the wax 658 from the trenches 656 and the openings 662.
  • the wax 658 may be removed via a solvent as noted above.
  • the method 600 may deposit a top hat layer 670 over the transport layer 664.
  • the top hat layer 670 may also be a photo-definable material or polymer (e.g., SU8).
  • the top hat layer 670 may include openings 672. The openings 672 may be formed via laser ablation or may be pre-patterned into the top hat layer 670 before the top hat layer 670 is laminated onto the transport layer 664.
  • the method 600 may deposit a microfluidic collection layer 674 onto the top hat layer 670.
  • the microfluidic collection layer 674 may include a channel 676.
  • the channel 676 in the microfluidic collection layer 674 may be formed via laser ablation or pre-patterned so that the microfluidic collection layer 674 can be laminated onto the top hat layer 670.
  • a cover layer 678 may be deposited onto the microfluidic collection layer 674.
  • the microfluidic collection layer 674 and the cover layer 678 may comprise a photo-definable polymer (e.g., SU8).
  • a cell collector 680 may be coupled to an opening 668 associated with the energy source 653i.
  • a cell supply 682 may be coupled to an opening 668 associated with the energy source 653 2 .
  • a reagent supply 684 may be coupled to an opening 668 associated with the energy source 653 3 .
  • a waste collector 686 may be coupled to an opening 668 associated with the energy source 653 4 .
  • the blocks 618 and 620 can be repeated to add as many layers in a vertical direction (e.g., z-axis 116 illustrated in FIG. 1) as desired.
  • the multi layered microfluidic system 680 may provide a complete system that can provide cells 112, internally inject the cells 112, and sort the cells 112. After the block 620 is completed, the multi-layered microfluidic system 680 may be completed.
  • the methods 200-600 illustrate various methods of fabricating different multi-layered microfluidic systems 280-680, it should be noted that different portions can be combined.
  • the process to include the trapping layer 362 or 470 can be included in the method 200, 500, or 600.
  • the additional layers illustrated in methods 600 may be incorporated into the method 300 or 400, and so forth.

Abstract

In example implementations, a method to fabricate a multi-channel microfluidic system is provided. The method includes providing an active substrate with an energy source. A chamber layer is then deposited on the active substrate and patterned with a chamber opening. The chamber filling is filled with a first wax layer. An intermediate layer with an opening is deposited on the chamber layer. The opening is located over the chamber layer opening. The opening in the intermediate layer is filled with a second wax layer. A microfluidic transport layer with a microfluidic transport channel is deposited on the intermediate layer. The microfluidic transport channel is located over the opening in the intermediate layer. The first wax layer and the second wax layer are removed. A top hat layer is applied over the microfluidic transport layer.

Description

FABRICATION OF MULTI-LAYER MICROFLUIDIC SYSTEMS
BACKGROUND
[0001] Microfluidic systems can be used for a variety of applications. Some examples may include using microfluidic systems to study cells. For example, cells can be inserted into a microfluidic system to be manipulated, sorted, and transported to various storage areas of the system for further analysis. Microfluidic systems may enable a system of dense interconnects of small size and complicated networks suitable for use in end-to-end integrated microfluidic functional systems. Cell transfections, blood cell sorting, separation and concentration, rear cell sensing, isolation and analysis, sample preparation, and the like are a few example applications that can use microfluidic systems.
BRIEF DESCRIPTION OF THE DRAWINGS [0002] FIG. 1 illustrates a block diagram of an example multi-layer microfluidic system that can be fabricated using the processes of the present disclosure;
[0003] FIG. 2A-2B is a process-flow diagram of an example method for fabricating a multi-layer microfluidic system of the present disclosure;
[0004] FIG. 3A-3B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure;
[0005] FIG. 4A-4B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure;
[0006] FIG. 5A-5B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure; and [0007] FIG. 6A-6B is a process-flow diagram of another example method for fabricating a multi-layer microfluidic system of the present disclosure.
DETAILED DESCRIPTION
[0008] Examples described herein provide a method for fabricating multi layer microfluidic systems. As noted above, microfluidic systems can be used for a variety of different applications. Fabrication of the micro-fluidic channels may not be trivial. Most microfluidic systems comprise a single layer. As a result, to increase the size of a system, the footprint of the microfluidic channel may increase considerably.
[0009] Most microfluidic devices are planar (e.g., a single layer). Microfluidic devices with multiple channels may be spread across the substrate and may have relatively large footprints. Some multi-layer fluidic channels with active substrate are overly complicated to manufacture or have channels that are too large (e.g., hybrid microfluidic channels with fabricated with polymers). Other multi-channel microfluidic channels may be passive with pneumatically driven chips. The passive systems do not include active substrates and include complicated pneumatic control systems.
[0010] The present disclosure provides a relatively low cost fabrication method that creates a multi-layer microfluidic system with a relatively small channel cross-section to reduce an amount of sample and reagent that is used, as well as decreasing the overall assay time.
[0011] Examples herein provide methods for fabricating multi-layer microfluidic systems that can be used for direct injection of reagents into a cell. The methods fabricate the multi-layer microfluidic system with active substrates and multiple layers of channels along a z-axis (e.g., vertical direction). The methods described herein allow well defined openings to be created despite high aspect ratio features in the multi-layer microfluidic systems of the present disclosure.
[0012] FIG. 1 illustrates a cross-sectional block diagram of an example multi layer microfluidic system 100 of the present disclosure. In an example, the multi-layer microfluidic system 100 may include a reagent chamber 102, a synthetic jet channel 104, and a channel 106. Cells 112i to 112n (hereinafter also referred to individually as a cell 112 or collectively as cells 112) are fed towards the synthetic jet channel 104 through the channel 106. In an example, the cells 112 may be moved through the channel 106 via a pump (not shown), gravity, capillary force, centrifugal force, electrophoretic force, dielectrophoretic force, and the like.
[0013] In an example, the sizing of the channel 106 may be a function of the size of the cell 112. The sizing may refer to the dimensions (e.g., length and width) of the cross-sectional opening of the channel 106. The size of the channel 106 may be large enough to allow the passage of a single cell 112 at a time.
[0014] In an example, the synthetic jet channel 104 may comprise a volume located between an opening of the reagent chamber 102 and an opening in the channel 106. The synthetic jet channel 104 may include an energy source 108 to heat a liquid in the synthetic jet channel 104 to generate a synthetic jet 110. The synthetic jet 110 may move at a velocity sufficient to carry a reagent 114 in the synthetic jet channel 104 towards the cell 112. For example, a cell
Figure imgf000005_0001
may be positioned adjacent to the synthetic jet channel 104 and the energy source 108 to receive the reagent 114. The synthetic jet 110 may porate the cell 1122 to allow the reagent 114 to be injected into the cell 1122. Thus, when the term “injection” is used herein it may include the action of poration of the cell and insertion of the reagent 114. The synthetic jet 110 may also move the reagent 114 towards the cell 1122 to inject the reagent 114 into the cell 1122. [0015] In an example, the synthetic jet 110 may be defined as a jet of the same fluid as the surrounding fluid (e.g., a jet of air formed within air or a jet of water formed within water). In an example, the synthetic jet 110 may be formed as a jet of a liquid created within the liquid in the synthetic jet channel 104. In other words, the synthetic jet 110 is formed from the surrounding liquid rather than an external source or fluid. In an example, the liquid may be water, a solvent, or any other liquid that is compatible with the reagent 114 and the cells 112.
[0016] In an example, the synthetic jet 110 may be formed by the energy source 108. The energy source 108 may locally heat the liquid in the synthetic jet channel 104 to create vapor bubbles of the liquid. As the vapor bubbles burst, the energy released by the bursting vapor bubbles may create the synthetic jet 110. The synthetic jet 110 may move in a direction of the bursting vapor bubbles. The energy source 108 may be arranged to direct the synthetic jet 110 towards an opening of the synthetic jet channel 104 where a cell 112 is located to receive the reagent 114.
[0017] In an example, the energy source 108 may be an inductive heater or a resistor heater. An example of a resistor heater may be a thermal inkjet (TIJ) resistor. A TIJ resistor may include a controllable circuit that includes a resistor heater. When the circuit is activated, current may flow through the resistor heater to generate heat.
[0018] In an example, the multi-layer microfluidic system 100 may be connected to additional components that are not shown. For example, the multi-layer microfluidic system 100 may include a cell source, a collector, and a controller. The controller may control operation of various devices (e.g., the energy source 108). After the cells 112 are injected with the reagent 114, the cells 112 may be fed to a collector for further sorting and/or analysis.
[0019] The collector may be a collection apparatus such as a container, individual wells of a well array, and the like. In an example, the collector may form a continuous loop. For example, the cells 112 may travel from the collector back to the cell source. For example, some cells 112 may not be injected when fed through the multi-layer microfluidic system 100. As a result, some cells 112 may be collected in the collector and other cells 112 may be fed back to the cell source to form a loop.
[0020] It should be noted that FIG.1 illustrates an example the multi-layered microfluidic system 100. However, the multi-layered fluidic system 100 may be varied with additional features (e.g., a trapping notch, additional chambers, additional vertical layers, in-situ cell sorting, and the like). The additional layers may be built along a z-axis 116, shown in FIG. 1.
[0021] FIGs. 2A-2B, 3A-3B, 4A-4B, 5A-5B, and 6A-6B illustrate process-flow diagrams of different methods for fabricating the multi-layered microfluidic system 100, as well as other variations of the multi-layered microfluidic system 100. The methods illustrated in FIGs. 2A-2B, 3A-3B, 4A-4B, 5A-5B, and 6A-6B may be performed by various tools in a fabrication plant. The tools may be controlled by a central controller or processor.
[0022] In an example, it should be noted that each layer may be grown or deposited using existing fabrication techniques, unless otherwise noted. For example, the layers described in the FIGs. 2 A-2B, 3A-3B, 4A-4B, 5A-5B, and 6A-6B may be deposited via sputtering, thermally grown, mechanically spun on, and so forth. In addition, each layer may be chemically and/or mechanically polished to provide a smooth flat surface to receive a subsequent layer.
[0023] FIGs. 2A-2B illustrate a method 200 for fabricating a multi-layered microfluidic system 280. At block 202, the method 200 may provide a substrate 250. The substrate 250 may be an active substrate that is electrically functional. For example, the substrate 250 may be silicon (Si), a complementary metal oxide semiconductor (CMOS), a printed circuit board (PCB), and the like.
[0024] In an example, the substrate 250 may include an energy source 253. The energy source 253 may be formed in the substrate 250 or electrically coupled to the substrate 250. The energy source 253 may be a TIJ resistor similar to the energy source 108 illustrated in FIG. 1 , and described above. [0025] In an example, a primer layer 252 may be deposited onto the substrate 250. The primer layer 252 may be a photo-definable material or polymer (e.g., SU8). A trench 256 may be etched in the primer layer 252. The trench 256 may be located over the energy source 253. For example, the trench 256 may expose a portion of the substrate 250 that includes the energy source 253.
[0026] At block 204, the method 200 may deposit a chamber layer 254. The chamber layer 254 may be formed from a photo-definable material or polymer (e.g., SU8). The trench 256 may be etched and extended through the chamber layer 254. The trench 256 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, as illustrated in FIG. 1 , and discussed above.
[0027] At block 206, the method 200 may fill the trench 256 with a sacrificial wax 258. The wax 258 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers). The wax 258 may have a low molecular weight. The process performed at block 206 may also be referred to as a lost wax method. [0028] In an example, an intermediate layer 260 may be deposited onto the chamber layer 254 and the wax 258. In one embodiment, the intermediate layer 260 may be a photo-definable material or polymer (e.g., SU8).
[0029] At block 208, a photolithography process may be carried out to form an opening or bore 262 in the intermediate layer 260. The opening 262 may be located over the wax 258. In an example, the opening 262 may be formed to expose a portion of the wax 258. The opening 262 may be aligned with the energy source 253.
[0030] In an example, the photolithography process may include providing a mask or pattern over the intermediate layer 260. An energy source or light (e.g., ultra violet (UV) light may be directed over the mask to expose those portions of the intermediate layer 260 that are not covered by the mask (e.g., the portion where the opening 262 is formed). The intermediate layer 260 may be baked or heated after exposure. The intermediate layer 260 may then be etched to remove the portions of the intermediate layer 260 that were exposed to the energy source. The mask may then be etched away.
[0031] At block 210, the method 200 may fill the opening 262 with the wax 258. Using photolithography to form the opening 262 and then filling the opening 262 with the wax 258 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 262 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
[0032] At block 212, the method 200 may deposit a transport layer 264 over the intermediate layer 260 and the wax 258. The transport layer 264 may be a photo-definable material or polymer (e.g., SU8). In an example, the thickness of the transport layer 264 may be a function of a size of the cells 112. As noted above, the transport layer 264 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
[0033] In an example, an opening 266 may be etched into the substrate 250. The opening 266 may be located over a portion of the wax 258. For example, the opening 266 in the substrate 250 may expose a portion of the wax 258. In an example, the opening 266 may be on an opposite end of the wax 258 as the opening 262 that was formed in block 208 of the method 200. The opening 266 may also be formed in the substrate 250 in a portion that is over the wax 258 and adjacent to the energy source 253.
[0034] At block 214, a microfluidic channel 268 may be formed in the transport layer 264. The microfluidic channel 268 may be formed over the wax 258. The microfluidic channel 268 may formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1) through the microfluidic channel 268.
[0035] In an example, the microfluidic channel 268 may be formed via a photolithography process. In another example, the microfluidic channel 268 may be formed via laser ablation. In another example, the microfluidic channel 268 may be pre-patterned into the transport layer 264. The pre-patterned transport layer 264 may then be laminated onto the intermediate layer 260.
[0036] At block 216, the method 200 may remove the wax 258 from the trench 256 and the opening 262. The wax 258 may be removed via a solvent as noted above. In addition, a top hat layer 270 may be deposited over the transport layer 264 and the microfluidic channel 268. The top hat layer 270 may also be a photo-definable material or polymer (e.g., SU8).
[0037] At block 218, a chamber 272 may be coupled to the substrate 250 over the opening 266. The chamber 272 may be, for example, the reagent chamber 102 illustrated in FIG. 1 . After the block 218 is completed, the multi layered microfluidic system 280 may be completed.
[0038] FIGs. 3A-3B illustrate a method 300 for fabricating a multi-layered microfluidic system 380. At block 302, the method 300 may provide a substrate 350. The substrate 350 may be an active substrate that is electrically functional. For example, the substrate 350 may be Si, a CMOS, a PCB, and the like.
[0039] In an example, the substrate 350 may include an energy source 353. The energy source 353 may be formed in the substrate 350 or electrically coupled to the substrate 350. The energy source 353 may be a TIJ resistor similar to the energy source 108 illustrated in FIG. 1 , and described above.
[0040] In an example, a primer layer 352 may be deposited onto the substrate 350. The primer layer 352 may be a photo-definable material or polymer (e.g., SU8). A trench 356 may be etched in the primer layer 352. The trench 356 may be located over the energy source 353. For example, the trench 356 may expose a portion of the substrate 350 that includes the energy source 353.
[0041] At block 304, the method 300 may deposit a chamber layer 354. The chamber layer 354 may be formed from a photo-definable material or polymer (e.g., SU8). The trench 356 may be etched and extended through the chamber layer 354. The trench 356 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, illustrated in FIG. 1 , and discussed above.
[0042] At block 306, the method 300 may fill the trench 356 with a sacrificial wax 358. The wax 358 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers). The wax 358 may have a low molecular weight. The process performed at block 306 may also be referred to as a lost wax method. [0043] In an example, an intermediate layer 360 may be deposited onto the chamber layer 354 and the wax 358. In one embodiment, the intermediate layer 360 may be a photo-definable material or polymer (e.g., SU8).
[0044] At block 308, a photolithography process, as described above, may be carried out to form an opening or bore 362 in the intermediate layer 360.
The opening 362 may be located over the wax 358. In an example, the opening 362 may be formed to expose a portion of the wax 358. The opening 362 may be aligned with the energy source 353.
[0045] At block 310, the method 300 may fill the opening 362 with the wax 358. Using photolithography to form the opening 362 and then filling the opening 362 with the wax 358 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 362 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1. [0046] At block 312, the method 300 may deposit a trapping layer 362 over the intermediate layer 360. The trapping layer 362 may be a photo-definable material or polymer (e.g., SU8).
[0047] At block 314, the method 300 may etch a trench 364 over the opening 362. The size of the trench 364 may be in accordance with the size of the cells 112. For example, the trench 364 may be formed to be large enough to trap a single cell 112. The trench 364 may then be filled with the wax 358. The trench 364 may be formed below the energy source 363 and over the opening 362 such that a cell 112 may be temporarily held in place under the energy source 363 to be transfected with the reagent 114, as described above.
[0048] At block 316, the method 300 may deposit a transport layer 366 over the trapping layer 362 and the wax 358. The transport layer 366 may be a photo-definable material or polymer (e.g., SU8). In an example, the thickness of the transport layer 366 may be a function of a size of the cells 112. As noted above, the transport layer 366 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
[0049] In an example, an opening 368 may be etched into the substrate 350. The opening 368 may be located over a portion of the wax 358. For example, the opening 368 in the substrate 350 may expose a portion of the wax 358. In an example, the opening 368 may be on an opposite end of the wax 358 from the opening 362 that was formed in block 308 of the method 300. The opening 368 may also be formed in the substrate 350 in a portion that is over the wax 358 and adjacent to the energy source 353.
[0050] At block 318, a microfluidic channel 370 may be formed in the transport layer 366. The microfluidic channel 370 may be formed over the wax 358. The microfluidic channel 370 may be formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1) through the microfluidic channel 370.
[0051] In an example, the microfluidic channel 370 may be formed via a photolithography process. In another example, the microfluidic channel 370 may be formed via laser ablation. In another example, the microfluidic channel 370 may be pre-patterned into the transport layer 366. The pre-patterned transport layer 366 may then be laminated onto the trapping layer 362.
[0052] At block 320, the method 300 may remove the wax 358 from the trench 356, the opening 362, and the trench 364. The wax 358 may be removed via a solvent as noted above. In addition, a top hat layer 372 may be deposited over the transport layer 366 and the microfluidic channel 370. The top hat layer 372 may also be a photo-definable material or polymer (e.g., SU8). [0053] At block 322, a chamber 374 may be coupled to the substrate 350 over the opening 368. The chamber 374 may be, for example, the reagent chamber 102 illustrated in FIG. 1. After the block 322 is completed, the multi layered microfluidic system 380 may be completed.
[0054] FIGs. 4A-4B illustrate a method 400 for fabricating a multi-layered microfluidic system 480. At block 402, the method 400 may provide a substrate 450. The substrate 450 may be an active substrate that is electrically functional. For example, the substrate 450 may be Si, a CMOS, a PCB, and the like.
[0055] In an example, the substrate 450 may include an energy source 453. The energy source 453 may be formed in the substrate 450 or electrically coupled to the substrate 450. The energy source 453 may be a TIJ resistor similar to the energy source 108 illustrated in FIG. 1 , and described above.
[0056] In an example, a primer layer 452 may be deposited onto the substrate 450. The primer layer 452 may be a photo-definable material or polymer (e.g., SU8). A trench 456 may be etched in the primer layer 452. The trench 456 may be located over the energy source 453. For example, the trench 456 may expose a portion of the substrate 450 that includes the energy source 453.
[0057] At block 404, the method 400 may deposit a chamber layer 454. The chamber layer 454 may be formed from a photo-definable material or polymer (e.g., SU8). The trench 456 may be etched and extended through the chamber layer 454. The trench 456 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, illustrated in FIG. 1 , and discussed above.
[0058] At block 406, the method 400 may fill the trench 456 with a sacrificial wax 458. The wax 458 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers). The wax 458 may have a low molecular weight. The process performed at block 406 may also be referred to as a lost wax method. [0059] In an example, an intermediate layer 460 may be deposited onto the chamber layer 454 and the wax 458. In one embodiment, the intermediate layer 460 may be a photo-definable material or polymer (e.g., SU8).
[0060] At block 408, a photolithography process, as described above, may be carried out to form an opening or bore 462 in the intermediate layer 460.
The opening 462 may be located over the wax 458. In an example, the opening 462 may be formed to expose a portion of the wax 458. The opening 462 may be aligned with the energy source 453.
[0061] At block 410, the method 400 may fill the opening 462 with the wax 458. Using photolithography to form the opening 462 and then filling the opening 462 with the wax 458 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 462 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
[0062] At block 412, the method 400 may deposit a transport layer 464 over the intermediate layer 454 and the wax 458. The transport layer 464 may be a photo-definable material or polymer (e.g., SU8). In an example, the thickness of the transport layer 464 may be a function of a size of the cells 112. As noted above, the transport layer 464 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
[0063] In an example, a microfluidic channel 466 may be formed in the transport layer 464. The microfluidic channel 466 may be formed over the wax 458. The microfluidic channel 466 may be formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1) through the microfluidic channel 466.
[0064] In an example, the microfluidic channel 466 may be formed via a photolithography process. In another example, the microfluidic channel 466 may be formed via laser ablation. In another example, the microfluidic channel 466 may be pre-patterned into the transport layer 464. The pre-patterned transport layer 464 may then be laminated onto the intermediate layer 460.
[0065] At block 414, the method 400 may etch an opening 468 into the substrate 450. The opening 468 may be located over a portion of the wax 458. For example, the opening 468 in the substrate 450 may expose a portion of the wax 458. In an example, the opening 468 may be on an opposite end of the wax 458 from the opening 462 that was formed in block 408 of the method 400. The opening 468 may also be formed in the substrate 450 in a portion that is over the wax 458 and adjacent to the energy source 453.
[0066] At block 416, the method 400 may remove the wax 458 from the trench 456 and the opening 462. The wax 458 may be removed via a solvent as noted above.
[0067] At block 418, the method 400 may deposit a trapping layer 470 over the transport layer 464. The trapping layer 470 may be a photo-definable material or polymer (e.g., SU8). The trapping layer 470 may include an opening 472 located below the opening 462 and the energy source 453. The opening 472 may be sized to be large enough to trap a single cell 112. The opening 472 may be formed below the energy source 453 and over the opening 462 such that a cell 112 may be temporarily held in place under the energy source 453 to be transfected with the reagent 114, as described above.
[0068] In an example, the opening 472 in the trapping layer 470 may be formed via a photolithography process. In another example, the opening 472 in the trapping layer 470 may be formed via laser ablation. In another example, the opening 472 in the trapping layer 470 may be pre-patterned into the trapping layer 470. The pre-patterned trapping layer 470 may then be laminated onto the intermediate layer 460.
[0069] At block 420, a top hat layer 474 may be applied over the trapping layer 470. The top hat layer 474 may also be a photo-definable material or polymer (e.g., SU8).
[0070] At block 422, a chamber 476 may be coupled to the substrate 450 over the opening 468. The chamber 476 may be, for example, the reagent chamber 102 illustrated in FIG. 1 . After the block 422 is completed, the multi layered microfluidic system 480 may be completed. [0071] FIGs. 5A-5B illustrate a method 500 for fabricating a multi-layered microfluidic system 580. At block 502, the method 500 may provide a substrate 550. The substrate 550 may be an active substrate that is electrically functional. For example, the substrate 550 may be Si, a CMOS, a PCB, and the like.
[0072] In an example, the substrate 550 may include multiple energy sources 553i and 5532. The energy sources 553i and 5532 may be formed in the substrate 550 or electrically coupled to the substrate 550. The energy sources 553i and 5532 may be TIJ resistors similar to the energy source 108 illustrated in FIG. 1 , and described above.
[0073] In an example, the energy source 553i may be used to create a synthetic jet 110 and transfect the cells 112 with the reagent 114. The energy source 5532 may be used as a microfluidic pump to move the cells 112 within the different layers of the multi-layered microfluidic system 580.
[0074] In an example, a primer layer 552 may be deposited onto the substrate 550. The primer layer 552 may be a photo-definable material or polymer (e.g., SU8). Trenches 556 may be etched in the primer layer 552. The trenches 556 may be located over the energy sources 553i and 5532. For example, the trenches 556 may expose portions of the substrate 550 that include the energy sources 553i and 5532.
[0075] At block 504, the method 500 may deposit a chamber layer 554. The chamber layer 554 may be formed from a photo-definable material or polymer (e.g., SU8). The trenches 556 may be etched and extended through the chamber layer 554. One of the trenches 556 below the energy source 553i may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, as illustrated in FIG. 1 , and discussed above. The other trench 556 may be located over the energy source 5532 to collect the transfected cells 112 and move the cells 112 to another layer via the energy source 5532.
[0076] At block 506, the method 500 may fill the trenches 556 with a sacrificial wax 558. The wax 558 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers). The wax 558 may have a low molecular weight. The process performed at block 506 may also be referred to as a lost wax method. [0077] In an example, an intermediate layer 560 may be deposited onto the chamber layer 554 and the wax 558. In one embodiment, the intermediate layer 560 may be a photo-definable material or polymer (e.g., SU8).
[0078] At block 508, a photolithography process, as described above, may be carried out to form an opening or bore 562 in the intermediate layer 560.
The openings 562 may be located over the wax 558. In an example, the openings 562 may be formed to expose a portion of the wax 558. The openings 562 may be aligned with the energy sources 553i and 5532. The openings 562 may then be filled with the wax 558.
[0079] Using photolithography to form the openings 562 and then filling the openings 562 with the wax 558 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the openings 562 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
[0080] At block 510, the method 500 may deposit a transport layer 564 over the intermediate layer 554 and the wax 558. The transport layer 564 may be a photo-definable material or polymer (e.g., SU8). In an example, the thickness of the transport layer 564 may be a function of a size of the cells 112. As noted above, the transport layer 564 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
[0081] At block 512, the method 500 may form a microfluidic channel 566 in the transport layer 564. The microfluidic channel 566 may be formed over the wax 558. The microfluidic channel 566 may be formed to extend to an edge that is coupled to a cell source that feeds the cells 112 (illustrated in FIG. 1 ) through the microfluidic channel 566.
[0082] In an example, the microfluidic channel 566 may be formed via a photolithography process. In another example, the microfluidic channel 566 may be formed via laser ablation. In another example, the microfluidic channel 566 may be pre-patterned into the transport layer 564. The pre-patterned transport layer 564 may then be laminated onto the intermediate layer 560.
[0083] In addition, an opening 568 may be etched into the substrate 550. The opening 568 may be located over a portion of the wax 558 that fills the trench 556 that includes the energy source 553i. In an example, the opening 568 may be on an opposite end of the wax 558 from the opening 562 that was formed in the trench 556 that includes the energy source 553i.
[0084] At block 514, the method 500 may remove the wax 558 from the trenches 556 and the openings 562. The wax 558 may be removed via a solvent as noted above. In addition, a top hat layer 570 may be formed over the transport layer 564. The top hat layer 570 may also be a photo-definable material or polymer (e.g., SU8).
[0085] At block 516, the method 500 may create an opening 574 in the top hat layer 570. The opening 574 may be connected to an external collector, another chamber or channel of another multi-layered microfluidic system, and the like. The opening 574 may be formed via laser ablation or may be pre patterned into the top hat layer 570 before the top hat layer 570 is laminated onto the transport layer 564
[0086] In addition, a chamber 572 may be coupled to the substrate 550 over the opening 568. The chamber 572 may be, for example, the reagent chamber 102 illustrated in FIG. 1. After the block 516 is completed, the multi-layered microfluidic system 580 may be completed.
[0087] FIGs. 6A-6B illustrate a method 600 for fabricating a multi-layered microfluidic system 680. At block 602, the method 600 may provide a substrate 650. The substrate 650 may be an active substrate that is electrically functional. For example, the substrate 650 may be Si, a CMOS, a PCB, and the like.
[0088] In an example, the substrate 650 may include multiple energy sources 653i, 6532, 6533, and 6534. The energy sources 653i, 6532, 6533, and 6534 may be formed in the substrate 650 or electrically coupled to the substrate 650. The energy sources 653i, 6532, 6533, and 6534 may be TIJ resistors similar to the energy source 108 illustrated in FIG. 1 , and described above.
[0089] In an example, the energy source 6533 may be used to create a synthetic jet 110 and transfect the cells 112 with the reagent 114. The energy sources 653i, 6532, and 6534 may be used as microfluidic pumps to move the cells 112 within the different layers of the multi-layered microfluidic system 680. [0090] In an example, a primer layer 652 may be deposited onto the substrate 650. The primer layer 652 may be a photo-definable material or polymer (e.g., SU8). Trenches 656 may be etched in the primer layer 652. The trenches 656 may be located over the energy sources 653i, 6532, 6533, and 6534. For example, the trenches 656 may expose portions of the substrate 650 that include the energy sources 653i, 6532, 6533, and 6534.
[0091] At block 604, the method 600 may deposit a chamber layer 654. The chamber layer 654 may be formed from a photo-definable material or polymer (e.g., SU8). The trenches 656 may be etched and extended through the chamber layer 654. One of the trenches 656 below the energy source 5533 may form the volume where the reagent 114 may flow through and be jetted by the energy source 108, illustrated in FIG. 1 , and discussed above. The other trenches 556 may be located over the energy source 653i, 6532, and 6534 to collect the transfected cells 112 and move the cells 112 to another layer or chamber within the multi-layered microfluidic system 680.
[0092] At block 606, the method 600 may fill the trenches 656 with a sacrificial wax 658. The wax 658 may be an organic compound (e.g., an epoxy) or material with a low polymerization that is dissolvable in an organic, non-polar solvent (e.g., ethers). The wax 658 may have a low molecular weight. The process performed at block 606 may also be referred to as a lost wax method. [0093] At block 608, an intermediate layer 660 may be deposited onto the chamber layer 654 and the wax 658. In one embodiment, the intermediate layer 660 may be a photo-definable material or polymer (e.g., SU8).
[0094] In an example, a photolithography process, as described above, may be carried out to form openings or bores 662 in the intermediate layer 660. The openings 662 may be located over the wax 658. In an example, the openings 662 may be formed to expose a portion of the wax 658. The openings 662 may be aligned with the energy sources 653i, 6532, 6533, and 6534.
[0095] At block 610, the openings 662 may be filled with the wax 658. Using photolithography to form the openings 662 and then filling the opening 662 with the wax 658 before subsequent layers (discussed below) are added may allow for more precise control and droplet performance through the opening 662 at the smaller dimensions associated with the cells 112 and the micro-fluidic sized channel 106, illustrated in FIG. 1.
[0096] At block 612, the method 600 may deposit a transport layer 664 over the intermediate layer 654 and the wax 658. The transport layer 664 may be a photo-definable material or polymer (e.g., SU8). In an example, the thickness of the transport layer 664 may be a function of a size of the cells 112. As noted above, the transport layer 664 may be deposited to a thickness that will provide a channel that is sufficient to transport a single cell 112 at a time.
[0097] In addition, a microfluidic channel 666 may be formed in the transport layer 664. The microfluidic channel 666 may be formed over the wax 658. In an example, the microfluidic channel 666 may be formed via a photolithography process. In another example, the microfluidic channel 666 may be formed via laser ablation. In another example, the microfluidic channel 666 may be pre patterned into the transport layer 664. The pre-patterned transport layer 664 may then be laminated onto the intermediate layer 660.
[0098] At block 614, the method 600 may etch openings 668 into the substrate 650. The openings 668 may be located over a portion of the wax 658 that fills the trench 656 that includes the respective energy sources 653i, 6532, 6533, and 6534. In an example, the openings 568 may be formed on an opposite end of the wax 658 from the openings 662 that were formed in the trenches 656.
[0099] At block 616, the method 600 may remove the wax 658 from the trenches 656 and the openings 662. The wax 658 may be removed via a solvent as noted above.
[00100] At block 618, the method 600 may deposit a top hat layer 670 over the transport layer 664. The top hat layer 670 may also be a photo-definable material or polymer (e.g., SU8). In an example, the top hat layer 670 may include openings 672. The openings 672 may be formed via laser ablation or may be pre-patterned into the top hat layer 670 before the top hat layer 670 is laminated onto the transport layer 664.
[00101] At block 620, the method 600 may deposit a microfluidic collection layer 674 onto the top hat layer 670. The microfluidic collection layer 674 may include a channel 676. The channel 676 in the microfluidic collection layer 674 may be formed via laser ablation or pre-patterned so that the microfluidic collection layer 674 can be laminated onto the top hat layer 670.
[00102] In addition, a cover layer 678 may be deposited onto the microfluidic collection layer 674. The microfluidic collection layer 674 and the cover layer 678 may comprise a photo-definable polymer (e.g., SU8).
[00103] In an example, a cell collector 680 may be coupled to an opening 668 associated with the energy source 653i. A cell supply 682 may be coupled to an opening 668 associated with the energy source 6532. A reagent supply 684 may be coupled to an opening 668 associated with the energy source 6533. A waste collector 686 may be coupled to an opening 668 associated with the energy source 6534.
[00104] Although two layers are illustrated in FIG. 6B, it should be noted that the blocks 618 and 620 can be repeated to add as many layers in a vertical direction (e.g., z-axis 116 illustrated in FIG. 1) as desired. In addition, the multi layered microfluidic system 680 may provide a complete system that can provide cells 112, internally inject the cells 112, and sort the cells 112. After the block 620 is completed, the multi-layered microfluidic system 680 may be completed.
[00105] Although the methods 200-600 illustrate various methods of fabricating different multi-layered microfluidic systems 280-680, it should be noted that different portions can be combined. For example, the process to include the trapping layer 362 or 470 can be included in the method 200, 500, or 600. In addition, the additional layers illustrated in methods 600 may be incorporated into the method 300 or 400, and so forth.
[00106] In addition, other components may be added to the multi-layered microfluidic systems 280-680. For example, sensors and imaging systems may be added to track and monitor injection of the reagents 114 into the cells 112. [00107] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

Claims

1. A method, comprising: providing an active substrate with an energy source; depositing a chamber layer on the active substrate; patterning a first chamber opening in the chamber layer; filling the first chamber opening with a first wax layer; depositing an intermediate layer on the chamber layer and the first wax layer; patterning a first opening in the intermediate layer over the chamber layer and the first wax layer; filling the first opening in the intermediate layer with a second wax layer; depositing a first microfluidic transport layer with a microfluidic transport channel located over the first opening in the intermediate layer; removing the first wax layer and the second wax layer; and applying a top hat layer over the first microfluidic transport layer.
2. The method of claim 1 , further comprising: depositing a primer layer over the active substrate; and patterning a primer layer opening over the energy source.
3. The method of claim 1 , wherein the first microfluidic transport layer is pre patterned with the microfluidic transport channel and deposited via lamination.
4. The method of claim 1 , further comprising: etching a feed opening in the active substrate over the first chamber opening and adjacent to the energy source.
5. The method of claim 1 , further comprising: depositing a second microfluidic transport layer with a second microfluidic transport channel over the microfluidic transport layer before the top hat layer is applied.
6. The method of claim 1 , wherein the active substrate comprises a second energy source, the chamber layer includes a second chamber opening over the second energy source, and the intermediate layer comprises a second opening over the second chamber opening.
7. The method of claim 1 , further comprising: etching a top hat layer opening in the top hat layer; depositing a microfluidic collection layer that includes a collection chamber over the top hat layer opening; and depositing a cover layer over the microfluidic collection layer.
8. A method comprising: providing an active substrate with an energy source; depositing a chamber layer on the active substrate; patterning a chamber opening in the chamber layer; filling the chamber opening with a first wax layer; depositing an intermediate layer on the chamber layer and the first wax layer; patterning an opening in the intermediate layer over the chamber layer and the first wax layer; filling the opening in the intermediate layer with a second wax layer; depositing a trapping layer over the intermediate layer; patterning a trapping notch in the trapping layer over the opening in the intermediate layer; filling the trapping notch with a third wax layer; depositing a microfluidic transport layer with a microfluidic transport channel located over the trapping notch in the trapping layer; removing the first wax layer, the second wax layer, and the third wax layer; and applying a top hat layer over the microfluidic transport layer.
9. The method of claim 8, further comprising: etching a feed opening in the active substrate over the chamber opening and adjacent to the energy source.
10. The method of claim 9, further comprising: coupling a reagent supply to the feed opening.
11. The method of claim 8, wherein the removing comprises: pouring a solvent into the trapping notch to dissolve the third wax layer, the second wax layer, and the first wax layer.
12. A method, comprising: providing an active substrate with an energy source; depositing a chamber layer on the active substrate; patterning a chamber opening in the chamber layer; filling the chamber opening with a first wax layer; depositing an intermediate layer on the chamber layer and the first wax layer; patterning an opening in the intermediate layer over the chamber layer and the first wax layer; filling the opening in the intermediate layer with a second wax layer; depositing a microfluidic transport layer with a microfluidic transport channel located over the opening in the intermediate layer; removing the first wax layer and the second wax layer; applying a trapping layer with a trapping notch on the microfluidic transport layer, wherein the trapping notch is aligned with the opening in the intermediate layer; and applying a top hat layer over the trapping layer.
13. The method of claim 12, wherein the trapping layer comprises a pre patterned trapping layer with the trapping notch that is laminated onto the microfluidic transport layer.
14. The method of claim 12, wherein the trapping notch is formed via laser ablation after the trapping layer is deposited onto the microfluidic transport layer.
15. The method of claim 12, wherein the patterning the chamber opening and the opening in the intermediate layer comprises a photolithography process.
PCT/US2020/030718 2020-04-30 2020-04-30 Fabrication of multi-layer microfluidic systems WO2021221659A1 (en)

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