WO2014145528A1 - Dispositifs microfluidiques antisalissures et procédés associés - Google Patents

Dispositifs microfluidiques antisalissures et procédés associés Download PDF

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Publication number
WO2014145528A1
WO2014145528A1 PCT/US2014/030318 US2014030318W WO2014145528A1 WO 2014145528 A1 WO2014145528 A1 WO 2014145528A1 US 2014030318 W US2014030318 W US 2014030318W WO 2014145528 A1 WO2014145528 A1 WO 2014145528A1
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Prior art keywords
antifouling
lubricant
microfluidic
microfluidic device
channel
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PCT/US2014/030318
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English (en)
Inventor
Joanna Aizenberg
Tak Sing Wong
Xu HOU
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President And Fellows Of Harvard College
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Publication of WO2014145528A1 publication Critical patent/WO2014145528A1/fr

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    • 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
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/16—Antifouling paints; Underwater paints
    • C09D5/1656—Antifouling paints; Underwater paints characterised by the film-forming substance
    • C09D5/1662—Synthetic film-forming substance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
    • B01L2200/06—Fluid handling related problems
    • B01L2200/0673—Handling of plugs of fluid surrounded by immiscible fluid
    • 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
    • B01L2300/06—Auxiliary integrated devices, integrated components
    • B01L2300/069—Absorbents; Gels to retain a fluid
    • 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
    • B01L2300/0809—Geometry, shape and general structure rectangular shaped
    • B01L2300/0816—Cards, e.g. flat sample carriers usually with flow in two horizontal directions
    • 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
    • B01L2300/00—Additional constructional details
    • B01L2300/16—Surface properties and coatings
    • B01L2300/161—Control and use of surface tension forces, e.g. hydrophobic, hydrophilic
    • B01L2300/163—Biocompatibility

Definitions

  • the present application relates to microfiuidic devices. More particularly, the present application relates to preventing fouling in microfiuidic devices.
  • Glass is extremely chemically robust: it is resistant to corrosion and fouling, does not swell, and is compatible with a wide variety of chemicals, including organic solvents.
  • Glass can also be functionalized to control surface properties, to graft desirable chemical groups to the surface or to spatially control wettability.
  • glass capillary devices can be functionalized to spatially control wettability and can form double and triple emulsions, even using organic solvents.
  • glass devices are difficult to fabricate. Glass capillary devices require manual tip pulling to form the drop making nozzles and hand alignment to assemble the devices, tedious processes that are difficult to automate. Glass capillary can only be made to perform a small set of functions, such as forming drops.
  • glass microfluidics cannot be used for alkaline solution transport application.
  • Glass is hydrophilic with a net negative charge, so substances with the opposite charge tend to stick to it.
  • biofouling in marine environment as well as for medical diagnostic are critical issues for glass.
  • Silicon has a high elastic modulus (130-180 GPa) and is not easily made into active fluidic components such as valves and pumps. Silicon surface chemistry based on the silanol group (-Si-OH) is well developed, so modification is easily accomplished via silanes. Silicon is transparent to infrared but not visible light, making typical fluorescence detection or fluid imaging challenging for embedded structures. For silicon microfluidics, the nonspecific adsorption can be reduced or cellular growth improved through chemical modification of the surface.
  • LTCC Low-temperature cofired ceramic
  • LTCC is an aluminum oxide based material that comes in laminate sheets that are patterned, assembled, and then fired at elevated temperature. Due to its laminar nature, LTCC can be fabricated into complex three- dimensional devices where each layer can be inspected for quality control before inclusion in the stack. Because the surface charge of LTCC is negative, there is an electrostatic adsorption of charged molecules in solution.
  • PDMS Polydimethylsiloxane
  • TEFLON microfluidics shows good inertness to various chemicals and extreme resistance against all solvents. However, fouling problems still exist, especially for biological molecules.
  • PMMA Poly(methyl methacrylate)
  • PMMA patterns can be formed through hot embossing or injection molding. Several different methods for bonding to form microfluidic networks have been demonstrated. Because the surface charge of PMMA is negative, there is an electrostatic adsorption of charged molecules in solution.
  • PEG poly(ethylene glycol)
  • PEGDA poly(ethylene glycol)diacrylate
  • an antifouling microfluidic device includes a microfluidic channel within a porous membrane, said microfluidic channel having at least one cross-section dimension that is between 0.1 to 500 ⁇ that defines a geometry for passage of a transport fluid, a lubricant stably infused within the porous membrane and filling the microfluidic channel, and first and second openings connected to said microfluidic channel that allows flow of a transport fluid into and out of said microfluidic channel.
  • an antifouling microfluidic device includes a lower porous membrane, an upper encapsulating material, a central porous membrane disposed between the upper encapsulating material and the lower porous membrane, a microfluidic channel that defines a geometry for passage of a transport fluid, wherein the upper encapsulating material, the central porous membrane and the lower porous membrane define the upper, lower and side walls of the microfluidic channel, wherein the microfluidic channel has at least one cross-section dimension that is between 0.1 to 500 ⁇ , a lubricant infused within the lower porous membrane and the central porous membrane and forming a smooth coating of the lubricant over the surfaces of each of the porous membranes inside the microfluidic channel, and first and second openings in the upper encapsulating material that allows flow of the transport fluid into and out of the microfluidic channel.
  • an antifouling microfluidic device includes a first porous membrane, a second porous membrane, a third porous membrane, a fourth porous membrane, and a fifth porous membrane, the second porous membrane disposed between the first and third porous membranes, the fourth porous membrane disposed between the third and fifth porous membranes, a first microfluidic channel that defines a geometry for passage of a transport fluid, wherein the first, second and third porous membranes define the upper, lower and side walls of the first microfluidic channel, and wherein the first microfluidic channel has at least one cross-section dimension that is between 0.1 to 500 ⁇ ; a second microfluidic channel that defines a geometry for passage of the transport fluid, wherein the third, fourth and fifth porous membranes define the upper, lower and side walls of the second microfluidic channel, and wherein the second microfluidic channel has at least one cross-section dimension that is between 0.1 to 500 ⁇ ; the first microfluidic channel and the second
  • the lubricant is immiscible with the transport fluid.
  • the lubricant wicks into, wets and stably adheres within the lower, upper, and central porous membranes.
  • the lower, upper and central porous membranes are preferentially wetted by the lubricant rather than by the transport fluid.
  • the lubricant has a higher dynamic viscosity than the dynamic viscosity of the transport fluid during steady-state flow.
  • the lubricant is a perfluorinated liquid, silicone, a hydrocarbon, an ionic liquid, or a food-grade oil.
  • said microfluidic device comprising said lubricant stably infused within the porous membrane provides a more transparent microfluidic device compared to the device without the lubricant.
  • the lower, upper and central porous membranes are selected from the group consisting of polytetrafluoroethylene, polypropylene, polycarbonate, polyester, polyethersulfone (PES), polyvinylidenedifluoride (PVDF), polydimethylsiloxane, metals (e.g., aluminum) and combinations thereof.
  • the transport fluid is a biological fluid.
  • the transport fluid is a microparticle- and nanoparticle- containing fluid.
  • the transport fluid is blood.
  • the antifouling microfiuidic device further includes an encapsulating material.
  • the encapsulating material is an optically clear, mechanically rigid structure.
  • FIG. 1A shows a schematic illustration of the formation of a "slippery liquid- infused porous surface(s)" (SLIPS) microfiuidic device in accordance with certain embodiments;
  • FIG. IB is a zoomed-in schema of an inner surface of a SLIPS microfiuidic channel in accordance with certain embodiments
  • FIG. 1C shows a tapered microfiuidic channel demonstrating that the lubricant refills the microfiuidic channel when flow of transport fluid is stopped in accordance with certain embodiments
  • FIG. ID shows a conventional large scale flow cell where the opening between the walls are not filled with the lubricant
  • FIG. 2A shows exemplary top, middle and bottom layer of a SLIPS microfiuidic device in accordance with certain embodiments
  • FIG. 2B shows different microchannel geometries that can be formed in a SLIPS microfiuidic device in accordance with certain embodiments
  • FIG. 2C shows different SLIPS microfiuidic devices in accordance with certain embodiments
  • FIG. 2D shows the porous membrane of a SLIPS microfiuidic device being infused with a lubricant in accordance with certain embodiments
  • FIG. 3A shows optical image of polydimethylsiloxane (PDMS) microfluidic devices before injecting Rhodamine B water solution (RB) at (1), and fluorescent images of PDMS microfluidic devices before injecting RB at (2), after injecting RB at (3), and after injecting air at (4)in accordance with certain embodiments;
  • PDMS polydimethylsiloxane
  • FIG. 3B shows optical image of TEFLON microfluidic devices before injecting RB at (1), fluorescent images of TEFLON microfluidic devices before injecting RB at (2), after injecting RB at (3), and after injecting air at (4)in accordance with certain embodiments;
  • FIG. 3C shows fluorescent images of PDMS microfluidic device before injecting octane at (l)(with the optical image shown at top left), after injecting octane at (2), after injecting air(3), and after 15 min at (4) in accordance with certain embodiments;
  • FIG. 3D shows optical image of TEFLON microfluidic device before injecting octane at (1), fluorescent images of TEFLON microfluidic devices before injecting octane at (2), after injecting octane at (3), after injecting air at (4) in accordance with certain embodiments;
  • FIG. 3E shows optical (1) and fluorescent (2) images of the SLIPS microfluidic device before injecting RB, after injecting RB at (3), after injecting air at (4), after injecting octane at (5), after injecting air at (6), after injecting octane for a second time at (7), and after injecting air yet again at (8) in accordance with certain embodiments;
  • FIG. 3F shows fluorescent image of the SLIPS microfluidic device before injecting RB (optical image at top left)(l), after infusing RB 10 ⁇ / ⁇ for 1 hour (2), after infusing air 10 ⁇ / ⁇ (3), after 12 hours and infusing RB 10 ⁇ / ⁇ for 1 hour(4), after infusing air 10 ⁇ / ⁇ , and tiny RB drops inside green circle(5), after infusing DI water 10 ⁇ / ⁇ (6), after 18 hours and infusing RB 10 ⁇ / ⁇ for 6 hours(7), after infusing air and DI water(8) in accordance with certain embodiments;
  • FIG. 4A shows 3D confocal images of two layers SLIPS microfluidic device fabricated with the hydroxy terminated PDMS lubricant (dye DFSB-K175) in accordance with certain embodiments;
  • FIG. 4B shows the optical and fluorescent merged images of a channel wall of the two layers PDMS lubricant SLIPS microfluidic device (1) before infusing water,(2)while infusing with wate infusing with water at 50 ⁇ / ⁇ ,(4) while infusing with water at 100 ng with water at 200 ⁇ / ⁇ , and(6)after stopping the infusing of the water in accordance with certain embodiments;
  • FIG. 4C shows a plot of the thickness variation of the lubricant layer of the channel wall of SLIPS microfluidic device in accordance with certain embodiments
  • FIG. 4D shows sectional confocal images of three layers SLIPS microfluidic device using a KRYTOX 103 lubricant.
  • (1) shows infusing with RB at 10 ⁇ / ⁇
  • (2) shows infusing with RB at 50 ⁇ / ⁇
  • (3) shows infusing with RB at 100 ⁇ / ⁇
  • (5) shows infusing with RB at 200 ⁇ / ⁇
  • (6) shows infusing with RB at 300 ⁇ / ⁇ ⁇ in accordance with certain embodiments
  • FIG. 4E shows a plot of the thickness variation of the lubricant layer of the channel wall of SLIPS microfluidic device in accordance with certain embodiments
  • FIG. 4F shows the confocal image of three layers SLIPS microchannel wall with KRYTOX 103 lubricant by infusing RB 10 ⁇ / ⁇ and by infusing RB 200 ⁇ / ⁇ ⁇ (bottom), and the diagram of the transport mechanism of the microchannel (right)in accordance with certain embodiments;
  • FIG. 5A shows the resistance of the SLIPS microfluidic device from particles attachment in accordance with certain embodiments
  • FIG. 5B shows a conventional TEFLON microfluidic device that suffers from particles attachment
  • FIG. 6A shows the resistance of the SLIPS microfluidic device from proteins attachment in accordance with certain embodiments
  • FIG. 6B shows a conventional TEFLON microfluidic device that suffers from proteins attachment
  • FIG. 7A shows a fabricated SLIPS microfluidic device in accordance with certain embodiments
  • FIG. 7B shows resistance of the SLIPS microfluidic device from attachment of blood after 1 hour in accordance with certain embodiments
  • FIG. 7C shows a conventional TEFLON microfluidic device that suffers from attachment of blood after 1 hour in accordance with certain embodiments
  • FIG. 7D shows resistance of the SLIPS microfluidic device from attachment of blood after7 hours in accordance with certain embodiments
  • FIG. 7E shows a conventional TEFLON microfluidic device that suffers from attachment of bloodafter7 hours in accordance with certain embodiments
  • FIG. 7F shows resistance of the SLIPS microfluidic device (the same sample used for 7 hours, FIG. 7D) from attachment of blood after 24 hours in accordance with certain embodiments;
  • FIG. 8A shows a photographic image of a multilayer SLIPS microfluidic device having microchannels in accordance with certain embodiments
  • FIGS. 8B and 8C show schematics of a design for multilayer SLIPS microfluidic device having microchannels in accordance with certain embodiments.
  • FIGS. 8D and 8E show fluorescence images and the confocal images of multilayer SLIPS microfluidic device having microchannels infused with Rhodamine B aqueous solution in accordance with certain embodiments.
  • a universal antifouling microfluidic network that shows an outstanding inertness to various chemicals and organic solvents, resist adhesion from particles and proteins to complex fluids such as whole blood is described.
  • the present approach is fundamentally different from the previous strategies in that a dynamic fluid surface that consists of a porous structured membrane infused with a lubricating fluid is utilized to create an antifouling layer (SLIPS). Therefore, the present design can provide a platform for many applications of microchannel systems and accelerate the development of high performance microfluidic devices.
  • the universality of the present approach in resisting fouling can also provide technological solutions to ultra-sensitive medical diagnostics and analytics, material synthesis, and industrial applications where sensitivity and performance cannot be compromised.
  • Microfluidics offers fundamentally new exciting capabilities in physicochemical synthesis, chemical and biological analysis, its broad applications are significantly limited by drawbacks of the materials used to make them.
  • the fluid samples and the materials from which the microchannels are fabricated can all contribute to the problem that components from samples stick to the inner surfaces of microchannels, and the microfluidics' parts become encrusted, clogged, and eventually useless.
  • a microfluidic device refers to a device that includes one or more microfluidic channels designed to carry liquid samples, typically in volumes of less than one milliliter.
  • the microfluidic device can include other elements, such as fluid inlets, fluid outlets, and valves that actuate the flow of fluids into (e.g., twist valves), out of, and/or through the microfluidic channels.
  • the microfluidic channel forms a path through the microfluidic device and generally has at least one cross-section dimension that is less than about 1 mm, such as in the range from about 0.1 micron to about 500 microns.
  • the microfluidic channels can have lengths ranging from about a few microns to as long as 10 cm or even as long as several meters.
  • the microfluidic channels may be linear in shape, or have any desired geometries, including curved, serpentine, spiraled, and the like.
  • the microfluidic channels may intersect (e.g., cross-shaped intersections), diverge away (e.g., Y-shaped intersections, T-shaped intersection), or cross over one another.
  • the microfluidic device can have a total thickness between about a few tens of microns to a few tens of cm, such as between 10 micron to 2 cm, or 40 micron and 1 mm, and 70 to 500 micron.
  • the microfluidic device may further include a means to push fluid through the device, such as a syringe, a pump, a syringe pump, gravity, or combinations thereof.
  • flow rate within the microfluidic device can range from about 0.01 ⁇ / ⁇ to about 1 mL/min, more preferably from about 0.1 ⁇ / ⁇ to about 500 ⁇ / ⁇ . In certain cases, the flow rate ranges between about 10 ⁇ / ⁇ and about
  • the microfluidic devices of the present disclosure includes a microfluidic channel located within one or more porous membrane, with one or more inlet ports for transport of a transport fluid through the microfluidic channel.
  • the porous membrane is infused with a lubricant to form a smooth coating of the lubricant over the surfaces of the microfluidic channel.
  • the microfluidic device includes a lower/bottom porous membrane, an upper/top porous membrane, a central/middle porous membrane disposed between the upper and lower porous membranes.
  • the microfluidic device may further include a channel that defines a geometry for passage of a transport fluid, wherein the upper, central and lower porous membranes define the upper, lower and side walls of a microfluidic channel.
  • the microfluidic device further includes a lubricant infused within the lower porous membrane, the central porous membrane and the upper porous membrane and forming a smooth coating of the lubricant over the surfaces of each of the porous membranes inside the microfluidic channel.
  • the microfluidic device includes first and second openings in the upper porous membrane that allows fluid flow into and out of the microfluidic channel.
  • This concept can be generalized to multiple layers of channels to create a three dimensional microfluidics systems, where the transport fluid can enter from the device inlet, and pass through the channels in each layers and exit at the device outlet.
  • FIG. IB shows a zoomed in scheme near the microfluidic channel wall where the porous membrane, the lubricant and the transporting liquid is shown.
  • the SLIPS microfluidic devices can designed based on the following criteria: (1) the antifouling layer of the lubricant and the transport fiuids are immiscible, and (2) the lubricant wicks into, wets and stably adheres within the porous membranes, and the membranes are preferentially wetted by the lubricant rather than by the transport fluids.
  • a third criteria may be met where (3) the lubricant should avoid being taken away by the transport fiuids during the steady-state transport.
  • the first requirement can be achieved easily by the law of similarity and intermiscibility.
  • the second requirements can be satisfied by using micro/nano porous membranes whose large surface area, combined with chemical affinity for the fluids, facilitates complete wetting by, and adhesion of, the lubricant.
  • the lubricant can be made much more viscous than the transport fiuids, so that for various realistic flow rates of the fiuids, along the direction of the fluid transport, the movement of the lubricant is nearly negligible.
  • the porous membranes may be formed using any suitable porous material, such as a TEFLON, porous membrane.
  • the porous membranes may include PDMS, glass, silicon, LTCC, polypropylene, metallic (e.g., silver, aluminum), carbon, polyester (PETE), polyethersulfone (PES), polyvinylidenedifluoride (PVDF), Nylon, cellulose, and the like.
  • the porous membranes may be chemically functionalized with one or more functional groups that provide improved affinity with the lubricant to allow the lubricant to be stably immobilized therein.
  • the lubricant can be selected from any suitable material, such as a broad range of perfiuorinated fiuids (including but not limiting to the tertiary perfiuoroalkylamines (such as perfiuorotri-n-pentylamine, FC-70 by 3M, perfiuorotri-n- butylamine FC-40, etc.), perfluoroalkylsulfides and perfiuoroalkylsulfoxides, perfiuoroalkylethers, perfluorocycloethers (like FC-77) and perfluoropolyethers (such as KRYTOX family of lubricants by DuPont), perfluoroalkylphosphines and perfiuoroalkylphosphine oxides as well as their mixtures can be used for these applications); polydimethylsiloxane and their functional modifications; food compatible liquids (including but not limiting
  • the channel/openings may be formed by any suitable methods, such as laser cutting. In other embodiments, the channel/openings may be formed by blade cutting, photolithography and thermo or compression molding technique.
  • the device may be fully encapsulated in an encapsulating material, such as PMMA.
  • the encapsulating material may include glass, ceramics and metal.
  • the device may be assembled by stacking multiple layers of porous membranes, or by folding the porous membrane in the form of origami, which can then be encapsulated in the aforementioned encapsulating materials.
  • the porous membrane can be infused with a lubricant by submerging the microfluidic device into a bath of a lubricant. In yet other embodiments, the porous membrane can be infused with a lubricant by soaking the porous membrane prior to assembly of the SLIPS microfluidic device.
  • the porous membrane can be infused with a lubricant using the one or more inlets before the transport fluid is passed through the SLIPS microfluidic device.
  • the microfluidic channel may have at least one cross section dimensions that are less than 1 mm, such as any range from about 0.1 micron to about 1000 microns, 0.1 micron to about 500 microns, or the like.
  • the microfluidic channel may be completely filled with the lubricant until the transport fluid is introduced into the microfluidic channel, whereby the lubricant filling the channel is displaced by the transport fluid. Nevertheless, as the transport fluid displaces and flows through channels, the microfluidic channel may maintain a thin layer of lubricant layer over the porous membrane that form the walls of the microfluidic channel.
  • lubricant may fill the entirety of the microchannel when no transport fluid pass through the channels. As the transport fluid is introduced into the channels, the lubricant may be pushed backward inside the membrane. This effect may become more pronounced with increasing flow rate. While decreasing the flow rate, the lubricant may come back inside the channel, and finally seal the channel whenever the flow stops.
  • the thickness of the lubricant layer may be altered. However, above a certain flow rate (e.g., above 150 ⁇ / ⁇ for the examples described below), the thickness of the lubricant layer becomes very thin, but nearly unchanged. Without wishing to be bound by theory, a minimum lubricant layer thickness may be reached because the membrane is preferentially wetted by the lubricant rather than the transport fluid.
  • the lubricant may refill the entire cross section of the microfluidic channel.
  • microfluidic channels having a dimension that exceeds 1 mm may not allow refilling of the entire cross section of the microfluidic channel, which can then lead to loss of some of the advantageous properties more fully discussed below (e.g., transparency, ability to clean out channels, etc.).
  • FIG. 1C shows a tapered microfluidic channel that is about 200 micrometers in height and varies in width up to about 1 mm. As shown, the lubricant fills the entire channel when no transport fluid (e.g., water) passes through the channel (see "Before" image).
  • no transport fluid e.g., water
  • Such an ability to refill the entirety of the microfluidic channel can provide further interesting and beneficial applications. For example, by recognizing that a certain flow rate provides the minimum lubricant layer thickness, transport fluid containing a material of interest can be flowed through the microchannel device at a flow rate that provides a lubricant layer that is sufficiently thicker than the minimum lubricant layer thickness.
  • transport fluid containing a material of interest can be flowed through the microchannel device at a flow rate that provides a lubricant layer that is sufficiently thicker than the minimum lubricant layer thickness.
  • a "cleaning fluid" can be then sent through the channel at a higher flow rate so that any materials that may have become attached can be easily removed. Accordingly, the SLIPS microfluidic devices can be easily cleaned of any undesired, stuck material.
  • the transport liquid may be flowed through at a flow rate that provides the minimum lubricant layer thickness to (relatively speaking) promote attachment of certain desired materials that may be included in the transport fluid (e.g., preferentially allow certain materials inside the transport fluid to stick while other components continue to pass through). Then, when a sufficient amount of the material has been attached to the walls of the microfluidic channels, a "collection fluid" can be flowed through at a lower flow rate, which will increase the lubricant layer, leading to the attached materials to become unattached. Then, these materials can be collected within the collection fluid and collected accordingly.
  • the SLIPS microfluidic device may provide a number of advantages. First, the SLIPS microfluidic device does not suffer from fouling as in conventional microfluidic devices. Second, the SLIPS microfluidic device can provide a slippery channel sidewall so that plug flow conditions can arise, providing little resistance to the flow of the transport fluid. Third, the fully porous material nature of the device allows the lubricant to continuously replenish to the surface of the channel sidewall, leading to self-healing and self- lubrication actions for surface renewal.
  • the SLIPS microfluidic devices described herein provide a simple and universal solution for antifouling within a fluidic network, and this strategy can be applied to a broad variety of channels within low-surface-energy porous/textured materials, infused with a low surface tension (e.g., fluorinated) liquid.
  • the lubricating liquid is locked in place by the low-surface-energy structured membrane and provides a stable "antifouling" interface that can operate in various channels' shapes of microfluidics.
  • the SLIPS microfluidic devices described herein provide an impressive antifouling property against both polar and non-polar liquids.
  • significant fouling is observed for typical engineering materials used for microfluidics, such as PDMS and Teflon.
  • the liquid hydrocarbons of lower surface tension (Octane) is very easy to damage the PDMS microfluidics and soak the entire Teflon microfluidics.
  • the SLIPS microfluidic devices described herein do not exhibit such problems associated with conventional microfluidic devices.
  • Particles transport inside microchannels has its difficulties due to wall attachment of particles and following fouling and blocking of the passages.
  • Adsorption of proteins onto surfaces of microchannels can result in denaturing of proteins and consumption of precious samples.
  • Traditional superhydrophobic channels have limited antifouling capability as fouling will typically be induced by the strong hydrophobic interaction between the surface and the hydrophobic portion of biomolecules.
  • these microfluidic channels have shown limited capability to handle complex biological fluids, such as whole blood.
  • the SLIPS microfluidic devices described herein show excellent antifouling against various complex liquid mixtures, such as particles, proteins, and whole blood, that rapidly foul any existing microfluidics.
  • Teflon-based microfluidic channel had been reported to have extreme resistance against all solvents, particles, proteins and blood can still contaminate the Teflon microfluidic channels.
  • the SLIPS microfluidic devices provide antifouling properties for a much longer duration than any of the conventional microfluidic devices.
  • the bioinspired channels do not show degradation or fouling after multiple uses for an extended period of time, e.g., greater than 1, 2, 3, 4, 5 6 or even longer hours of continuous operations.
  • Transparent omniphobic microfluidic devices have not yet been reported in the literature.
  • the SLIPS microfluidic devices described herein not only possesses antifouling and omniphobic characteristics, but they can also be tuned optically transparent by infusing lubricant with matching optical refractive index with the porous solid materials. This property allows for the detection of optical signals through the channel materials, such as fluorescence signals.
  • TEFLON porous membranes There are two types of TEFLON membranes purchased from Sterlitech Corporation, WA, USA. The first one is the membrane with average pore size of > 5 ⁇ and thickness of -200 ⁇ . The second one is the membrane with average pore size of > 200 nm and thickness of ⁇ 30 ⁇ . These membranes were evaluated by scanning electron micrograph and contact angle measurements. For the confocal measurements described below, the second one was thinner as the top layer to get better fluorescent signal of the liquid transport inside the microchannel.
  • PDMS channels SYLGARD 184 SILICONE ELASTOMER BASE and SYLGARD 184 SILICONE ELASTOMER CURING AGENT were purchased from Dow coming corporation. PDMS mixed at a 10:1 curing ratio is placed into microfluidic molds and cured for 3 hours at 70 °C.
  • PMMA sheets The scratch-resistant clear cast acrylic sheet 1/16" thick, 12" X 12" and the scratch-resistant clear cast acrylic sheet 3/16" thick, 12" X 12" were purchased from McMaster Carr Supply Company.
  • the lubricant used for the experiments were KRYTOX 103 and the hydroxyl terminated PDMS lubricant (dye DFSB-K175). Unless otherwise specified, KRYTOX 103 was used throughout the antifouling experiments. PDMS lubricant with dye was used for the two layers SLIPS microchannel experiments to obtain the optimal 3D confocal fluorescent signal detection. Deionized water with a resistivity of 18.3 ⁇ -cm was used for the measurements.
  • the transport fluids were obtained from Sigma Aldrich which include octane (puriss, > 99.0%) and Rhodamine B (HPLC, > 97.0%).
  • Dye DFSB-K175 was obtained from www.riskreactor.com.
  • Interfacial dynamics microparticles in the suspension are the surfactant-free fluorescent yellow green sulfate latex which was obtained from Invitrogen, and the diameter is -1.6 ⁇ (8 ⁇ 1 ⁇ %: 1.9).
  • BSA bovine serum albumin
  • PBS Phosphate buffered saline
  • Sheep blood in heparin (3 IU/mL) was obtained from HemoStat Laboratories, CA, USA.
  • Rhodamine B water solution (RB): Rhodamine B was dissolved in a DI water to give the RB solution a final concentration of 0.1 mg/mL.
  • Fluorescent particles suspending solution The suspension was for 0.1 mL of a 1.9%) suspension in 2 mL H 2 0, so it is approximately a 0.10 Vol%> suspension.
  • Fluorescently labeled protein solution The solution was made with 1% fluorescein conjugated BSA, and it was diluted in IX PBS to a final total protein concentration of 1%.
  • the preparation of the channels on the membranes has almost no restrictions, and it is compatible with various other technologies to make all kinds of shapes of channels besides laser cutting, such as blade cutting, photolithography, and thermo and compression molding technique.
  • laser cutting such as blade cutting, photolithography, and thermo and compression molding technique.
  • clean room and other equipment such as photolithography followed by selective etching can be utilized.
  • the lubricant was infused inside the microfluidic channel, and the transparency of the microchannels increased significantly.
  • the contact angle measurements were performed by a contact angle measurement system (KSV CAM 101) at room temperature (i.e., 20 - 24 °C) with -20% relative humidity. The system was calibrated before all the measurements were taken.
  • the macroscopic droplet profile was captured through a camera equipped with an optical system for amplification of the captured image, where the droplet was fitted into a spherical cap profile by a computer program provided from the system in order to determine the advancing and receding angles, and the droplet volume.
  • the contact angle hysteresis i.e., difference between the advancing and receding angles
  • the droplet volume was increased/reduced until the contact line advances/recedes for the measurement of advancing/receding angles.
  • the accuracy of the contact angle measurements is -0.1°.
  • the sliding angle of the droplet was measured by a tilting stage with a resolution of 0.5°.
  • FIG. 2 A A series of microfluidic devices were fabricated to study both the antifouling and transport properties of the microchannels.
  • FIG. 2 A three layers microchannel membranes were prepared by using a laser cutting technology.
  • the laser cutting technique allows control over the shapes of the microchannel, and it can easily provide a stable "antifouling" interface that can operate in diversified channels' shapes of microfluidics from simple regular to complex irregular.
  • FIG. 2C shows various different shapes of the microchannel
  • an encapsulating material can be provided around the porous membranes and provided with desired inlet and outlet ports.
  • FIG. 2C shows various different shapes of the microchannel
  • FIG. 3A shows optical image of polydimethylsiloxane (PDMS) microfluidic devices before injecting Rhodamine B water solution (RB) at (1), and fluorescent images of PDMS microfluidic devices before injecting RB at (2), after injecting RB at (3), and after injecting air at (4);
  • PDMS polydimethylsiloxane
  • FIG. 3B shows optical image of TEFLON microfluidic devices before injecting RB at (1), fluorescent images of TEFLON microfluidic devices before injecting RB at (2), after injecting RB at (3), and after injecting air at (4);
  • FIG. 3C shows fluorescent images of PDMS microfluidic device before injecting octane at (l)(with the optical image shown at top left), after injecting octane at (2), after injecting air(3), and after 15 min at (4);
  • FIG. 3D shows optical image of TEFLON microfluidic device before injecting octane at (l),fluorescent images of TEFLON microfluidic devices before injecting octane at (l),fluorescent images of TEFLON microfluidic devices before injecting octane at
  • FIGS. 3A and 3B a significant amount of the residual RB are observed on both the walls of a PDMS channel (FIG. 3A) and a TEFLON channel (FIG. 3B)after RB transport inside the microchannels.
  • a PDMS channel FIG. 3A
  • a TEFLON channel FIG. 3B
  • octane is very easy to damage the PDMS microfluidics (FIG. 3C) and soak the entire TEFLON microfluidics (FIG. 3D), scale bar 100 ⁇ .
  • FIG. 3E shows optical (1) and fluorescent images of the SLIPS microfluidic device before injecting RB(2), after injecting RB(3), after injecting air(4), after injecting octane (5), after injecting air(6), after injecting octane for a second time (7), and after injecting air yet again (8).
  • no fouling and soaking of the channel can be observed after twice infusing octane, scale bar 100 ⁇ .
  • FIG. 3F shows fluorescent image of the SLIPS microfluidic device before injecting RB (optical image at top left) (1), after infusing RB 10 ⁇ / ⁇ for 1 hour (2), after infusing air 10 ⁇ / ⁇
  • FIG. 3F (1-3) After 12 hours, the channel was infused with RB again for 1 hour.
  • FIG. 3F (4) After injecting the channel with air, there were several tiny inconspicuous RB drops inside the channel.
  • FIG. 3F (5) After washing with DI water, no fluorescent signal can be seen on the wall of the channel.
  • FIG. 3F(6) After 18 hours, the channel was infused with RB again for 6 hours. After injecting the channel with air and washing with DI water, no fluorescent signal can be seen on the wall of the channel, and this super cleanness of the SLIPS microfluidic device is of great importance to quantitative analysis application.
  • FIG. 4A shows 3D confocal images of two layers SLIPS microfluidic device fabricated with the hydroxy terminated PDMS lubricant (dye DFSB-K175).
  • (1) shows the SLIPS microfluidic device before infusing with DI water.
  • (2) shows the SLIPS microfluidic device after infusing with DI water at 200 ⁇ / ⁇ .
  • (3) shows the SLIPS microfluidic device after the infusement with DI water was stopped.
  • infusing the SLIPS microfluidic device with the DI water is a reversible process.
  • FIG. 4B shows the optical and fluorescent merged images of a wall of the two layers PDMS SLIPS microfluidic device (1) before infusing water, (2) while infusing with water at 10 ⁇ / ⁇ (3) while infusing with water at 50 ⁇ / ⁇ , (4) while infusing with water at 100 ⁇ / ⁇ , (5) while infusing with water at 200 ⁇ / ⁇ , and (6) after stopping the infusing of the water.
  • Scale bar is 20 ⁇ .
  • the results reveal the thickness of the antifouling lubricant layer decreases by increasing the liquid flow rate from 10 to 200 ⁇ / ⁇ .
  • the thickness variation of the lubricant layer of the channel wall is plotted in FIG.
  • the inset represents measured position 1, 2, 3 and 4of the channel, scale bar 200 ⁇ .
  • the change of the cross-sectional size of transport fluid inside the channel is equivalent to the thickness variation of the lubricant layer with different flow rates, because the antifouling layer of the lubricant and the transport fluid are immiscible.
  • FIG. 4D shows sectional confocal images of three layers SLIPS microfluidic device using a K YTOX 103 lubricant, (l)shows infusing with RB at 10 ⁇ / ⁇ , (2) shows infusing with R infusing with RB at 100 infusing with RB at 150 g with RB at 200 ⁇ / ⁇ , and (6)shows infusing with RB at 300 ⁇ / ⁇ .
  • Scale bar is 50 ⁇ .
  • the thickness variation of RB as the transport liquid inside the microchannel with different flow rates was plotted in FIG. 4E.
  • the inset represents measured position 1, 2, 3 and 4of the channel, scale bar 120 ⁇ .
  • the change of the cross-sectional size of liquid with different flow rates shows the same trend as that of the two layers SLIPS microfluidic device.
  • the thickness of the antifouling lubricant layer appears to decrease by increasing the flow rates of the transport liquid, (see FIG. 4F, left) and when the flow rate reached a certain level, the decrease of the lubricant layer was kept nearly unchanged (see FIGS. 4C and 4E).
  • the lubricant layer appears to cover the porous structure membrane which serves as a reservoir of the lubricant. Initially, the lubricant may fill all of the microchannel. By increasing the liquid flow rate, the lubricant may be pushed backward inside the membrane. While decreasing the flow rate, the lubricant may come back inside the channel, and finally seal the channel whenever the flow stops.
  • the minimum thickness of the lubricant may be determined by the intermolecular force between the lubricant and the membrane. Further increasing the flow rate may not lead to further decrease of the lubricant layer thickness due to the liquid-liquid super smooth surface which keeps refreshing to prevent the fluid fouling.
  • f , 1 are the dynamic viscosity of the transport fluid and the lubricant respectively.
  • the dynamic viscosity of the transport fluid is smaller than the dynamic viscosity of the lubricant.
  • the dynamic viscosity of the transport fluid is smaller than the dynamic viscosity of the lubricant with more than two orders of magnitude.
  • ⁇ f and ⁇ 1 are the characteristic velocity of the two liquids.
  • ⁇ is the scale of radius of the transport liquid, while ⁇ is the scale of thickness of the lubricant layer.
  • t is smaller than R with more than one order of magnitude, when the liquid flow rate is more than or equal to 10 ⁇ / ⁇ , t ⁇ ⁇ ⁇ ;£/m and R > ⁇ 60 / m
  • U is smaller than tT/with more than three orders of magnitude, which means the antifouling lubricant layer can be effectively stationary relative to the transport fluid layer.
  • FIG. 5A (1) shows micro particles with fluorescent signal in DI water solution.
  • FIG. 5A (2- 10) shows fluorescent images of both the adjacent top and bottom layers of the SLIPS microfluidic device before and after infusing the channel with the solution of particles (endurance time: 15 min). No fouling of the channel can be observed after the repeated trials, (see FIG. 5A (11, 12))
  • FIG. 5B shows that a significant amount of the particles is observed on the adjacent bottom layer of the two layers TEFLON channel.
  • the antifouling properties of the SLIPS microfluidic devices have been tested by infusing BSA protein solution as the transport fluid and repeatedly pausing the flow of the transport fluid.
  • the microchannel shows excellent resistance to protein solution, and no fluorescent signal against background can be seen on the wall of the channel under a fluorescent microscope, (see FIG. 6A (1-12))
  • a conventional microfluidic device made of TEFLON was utilized, a significant amount of the protein is observed on the adjacent bottom layer of the TEFLON channel, (endurance time: 15 min, FIG. 6B (1-4)).
  • the SLIPS microfluidic devices described herein exhibit an impressive antifouling property against both polar and non-polar liquids.
  • significant fouling is observed for typical engineering materials used for microfluidics, such as PDMS and Teflon.
  • the liquid hydrocarbons of lower surface tension (Octane) is very easy to damage the PDMS microfluidics and soak the entire Teflon microfluidics.
  • FIG. 7A shows the SLIPS microfluidic device. The antifouling properties have been studied by infusing sheep whole blood with different time.
  • FIG. 7B After infusing blood for 1 hour, no residual blood can be seen on the SLIPS membranes (FIG. 7B (1-4)), but there is still visible blood stain on the TEFLON membranes after rinsing by DI water.
  • FIG. 7C After infusing blood for 7 hours, there are several tiny inconspicuous blood drops on the membranes of the SLIPS microfluidic device, and after rinsing by DI water no residual blood can be seen on the membranes.
  • FIG. 7D (1-8)
  • a significant amount of the blood drops are observed on the TEFLON membranes, and after rinsing by DI water there are still very clear blood stain on the membranes.
  • FIG. 7E shows the membranes of the SLIPS microfluidic device after a 24 hours test and rinsing by DI water. As shown, no residual blood can be seen on the membranes, which means it could potentially promote a platform for the new generation of microfluidics for biomedical application.
  • FIGS. 8A through 8E show the design and images of a multilayer SLIPS microfluidic device having microchannels on three different layers which are in fluid communication with one another.
  • FIG. 8A shows a top view photographic image of a multilayer SLIPS microfluidic device having an inlet and an outlet.
  • FIGS. 8B and 8C show schematics of a design for multilayer SLIPS microfluidic device having microchannels on different layers and how they are in fluid communication with one another.
  • the constructed multilayer SLIPS microfluidic device was then infused with Rhodamine B aqueous solution and FIGS. 8D and 8E show the resulting fluorescence images and the confocal images.
  • Pvhodamine B is present in the microfluidic channels residing in 2 nd , 4 th and 6 th layer.
  • the rectangular boxes in FIG. 8B indicate where these images were obtained.
  • the SLIPS microfluidic device of the present disclosure displays outstanding antifouling behavior.
  • Any desired microfluidic channels can be prepared without restriction, and it is compatible with various technologies for making any desired shapes of channels, such as laser cutting, blade cutting, photolithography and thermo molding techniques.
  • the SLIPS microfluidics can be constructed into 1-D, 2-D, and 3-D systems by stacking multiple layers of the channel-containing porous membranes. The material are also very simple with many existing membranes and lubricants already used for slippery surface applications. Therefore, the SLIPS microfluidic device can be easily achieved without extraordinary care or preparation which will benefit its large area application. As microfluidics research continues to push the limits, having various strategies to prevent fouling will become more critical.
  • the SLIPS microfluidic device described herein and the broader application of microfluidic antifouling strategies hold significant promise for a broad range of industrial and biomedical products, and for providing a basic platform aimed at the development of biomimetic smart channel fluid systems.

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Abstract

La présente invention concerne un dispositif microfluidique antisalissure. Les dispositifs microfluidiques antisalissures peuvent être fabriqués en utilisant simplement des membranes à structure poreuse imprégnées d'un lubrifiant pour former une structure glissante poreuse imprégnée d'un liquide (SLIPS). Des membranes à microcanaux à trois couches sont fabriquées en découpant des canaux désirés dans une membrane poreuse, en empilant différentes membranes poreuses autour de la membrane découpée et en encapsulant les membranes poreuses. Les membranes poreuses peuvent être imprégnées d'un lubrifiant, ce qui permet d'améliorer significativement la transparence des microcanaux. Le dispositif microfluidique antisalissure à SLIPS peut facilement créer une interface « antisalissure » stable susceptible de fonctionner avec de quelconques formes de canaux désirées et dans une large plage d'environnements, la salissure des canaux microfluidiques étant considérablement réduite.
PCT/US2014/030318 2013-03-15 2014-03-17 Dispositifs microfluidiques antisalissures et procédés associés WO2014145528A1 (fr)

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WO2018039084A1 (fr) 2016-08-20 2018-03-01 The Regents Of The University Of California Système et procédé à haut débit pour la perméabilisation temporaire de cellules
CN108212234A (zh) * 2018-01-19 2018-06-29 天津大学 一种微流控芯片加工方法以及用于加工该芯片的工具箱
US11351536B2 (en) 2017-10-31 2022-06-07 The Penn State Research Foundation Biochemical analysis system
CN115305471A (zh) * 2022-08-31 2022-11-08 模德模具(东莞)有限公司 特种抗血渍纹理制作工艺

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WO1993017077A1 (fr) * 1992-02-21 1993-09-02 Dunton Ronald K Revetements de poly(ethylene fluore)
US6756019B1 (en) * 1998-02-24 2004-06-29 Caliper Technologies Corp. Microfluidic devices and systems incorporating cover layers
WO2009121037A2 (fr) * 2008-03-27 2009-10-01 President And Fellows Of Harvard College Dispositifs microfluidiques tridimensionnels
WO2012100100A2 (fr) * 2011-01-19 2012-07-26 President And Fellows Of Harvard College Surfaces glissantes poreuses imprégnées de liquides et leur application biologique

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018039084A1 (fr) 2016-08-20 2018-03-01 The Regents Of The University Of California Système et procédé à haut débit pour la perméabilisation temporaire de cellules
US11999931B2 (en) 2016-08-20 2024-06-04 The Regents Of The University Of California High-throughput system and method for the temporary permeabilization of cells
US11351536B2 (en) 2017-10-31 2022-06-07 The Penn State Research Foundation Biochemical analysis system
US11938476B2 (en) 2017-10-31 2024-03-26 The Penn State Research Foundation Biochemical analysis system
CN108212234A (zh) * 2018-01-19 2018-06-29 天津大学 一种微流控芯片加工方法以及用于加工该芯片的工具箱
CN115305471A (zh) * 2022-08-31 2022-11-08 模德模具(东莞)有限公司 特种抗血渍纹理制作工艺

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