US20110036479A1 - Micro fluid system support and manufacturing method thereof - Google Patents

Abstract

A support unit for a microfluidic system includes a first support; a first adhesive layer provided on a surface of the first support; and a hollow filament laid on a surface of the first adhesive layer to have an arbitrary shape and functioning as a flow channel layer of the microfluidic system.

Description

• This application is a divisional of U.S. application Ser. No. 12/496,212, filed on Jul. 1, 2009, which is a divisional of U.S. application Ser. No. 10/505,416, filed on Jun. 13, 2005, pending, which is a National Stage of International Application No. PCT/JP2003/02066, filed on Feb. 25, 2003.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to a support unit for a microfluidic system, in which a hollow filament is laid on and fixed to a support to have a predetermined shape, and a manufacturing method thereof.
• 2. Description of the Related Art
• In chemical and biochemical fields, studies have advanced to miniaturization of reaction systems and analyzers that use microelectromechanical systems (MEMS). In conventional research and development, there is a micron-scale machine element (referred to as “micromachine” hereinafter) having a single function as a micromotor or micropump.
• In order to conduct an intended chemical reaction or chemical analysis, it is necessary to combine a plurality of various micromachine parts together and systemize them. A complete form of such system is referred to by such names as micro reactor system, or micro total analysis system (μTAS). Usually, micromachines are formed on a silicon chip by applying a semiconductor manufacturing process. In principle, it is possible to form (integrate) a plurality of elements on one chip systemizing them, and efforts have been made in fact toward this operation. However, the fabrication process of the system is complicated, and it is assumed difficult to manufacture the system at a mass production level. A chip substrate (referred to as nanoreactor hereinafter), where a groove is formed as a flow channel by etching or the like at a predetermined position in a silicon substrate, has been suggested as a method of connecting a plurality of micromachines to form a fluidic circuit (system). This method has an advantage in that manufacturing of the system is far easier than manufacturing of the system in the aforementioned method of integration. However, a cross-sectional area of the flow channel is small, and interface resistance between a fluid and the side surface of the groove is large. Thus, under the present circumstances, the maximum length of the flow channel is not more than millimeters, and, in synthetic reactions and chemical reactions that are actually conducted, the number of steps and the amount of a fluid for reaction and analysis are limited.
• However, the fabrication process of the system is complicated, and it is assumed difficult to manufacture the system at a mass production level. Therefore, in recent years, a chip substrate, where a groove is formed as a flow channel by etching or the like at a predetermined position in a silicon substrate, has been suggested as a method of connecting a plurality of micromachines to form a fluidic circuit. This method has an advantage in that manufacturing of the system is far easier than manufacturing of the system in the aforementioned method of integration. However, on the other hand, this method has a problem in that a cross-sectional area of the flow channel is small, and interface resistance between a fluid and the side surface of the groove is large. Thus, under the present circumstances, the maximum length of the flow channel is not more than millimeters, and, in synthetic reactions and chemical reactions that are actually conducted, the number of steps and the amount of a fluid for reaction and analysis are limited.
SUMMARY OF THE INVENTION
• The present invention was accomplished to resolve the above-described problem. In other words, an object of the present invention is to provide a support unit for a microfluidic system, which is manufactured easily and has a long flow channel in centimeters that does not limit the number of steps and an amount of a fluid for reaction and analysis.
• Another object of the present invention is to provide a support unit for a small microfluidic system, which does not require space even with a complicated fluidic circuit.
• Yet another object of the present invention is to provide a manufacturing method for a support unit for a microfluidic system, in which a complicated fluidic circuit can be formed.
• In order to achieve the above object, a first aspect of the present invention inheres in a support unit for a microfluidic system including (a) a first support, (b) a first adhesive layer provided on a surface of the first support, (c) a hollow filament laid on a surface of the first adhesive layer to have an arbitrary shape, and (d) a hollow filament laid on the surface of the first adhesive layer to have an arbitrary shape and functioning as a flow channel layer of a microfluidic system. In the first aspect of the present invention, another hollow filament can be three-dimensionally laid in a manner of intersecting with said hollow filament. Therefore, it becomes possible to provide a support unit for a microfluidic system which has good accuracy, can be manufactured easily and has a long flow channel in centimeters that does not limit the number of steps and the amount of a fluid for reaction and analysis. Further, according to the first aspect of the present invention, it is possible to provide a support unit for a small microfluidic system, which does not require space even with a complicated fluidic circuit. Thus, it is also possible to downsize the microfluidic system itself.
• A second aspect of the present invention inheres in a support unit for a microfluidic system including (a) a first support, (b) a first adhesive layer provided on a surface of the first support, and (c) a first hollow filament group constituted by a plurality of hollow filaments laid on a surface of the first adhesive layer to have an arbitral shape and respectively functioning as a plurality of flow channel layers of the microfluidic system. In the second aspect of the present invention, a second hollow filament group constituted by a plurality of hollow filaments can be three-dimensionally laid to intersect the first hollow filament group constituted by the plurality of hollow filaments. Therefore, it becomes possible to provide a support unit for a microfluidic system which has good accuracy, can be manufactured easily and has a long flow channel in centimeters that does not limit the number of steps and the amount of a fluid for reaction and analysis. Further, according to the first aspect of the present invention, it is possible to provide a support unit for a small microfluidic system, which does not require space even with a complicated fluidic circuit. Thus, it is also possible to downsize the microfluidic system itself.
• A third aspect of the present invention inheres in a manufacturing method of a support unit for a microfluidic system including (a) forming a first adhesive layer on a surface of a first support, and (b) laying a hollow filament on a surface of the first adhesive layer. The manufacturing method of a support unit for a microfluidic system according to the third aspect of the present invention is a manufacturing method using the support unit for a microfluidic system explained in the first aspect. According to the third aspect of the present invention, it is possible to provide a manufacturing method of a support unit for a small microfluidic system in which a complicated fluidic circuit can be formed.
• A fourth aspect of the present invention inheres in a manufacturing method of a support unit for a microfluidic system including (a) forming a first adhesive layer on a surface of a first support, and (b) laying a first hollow filament group constituted by a plurality of hollow filaments on a surface of the first adhesive layer. The manufacturing method of a support unit for a microfluidic system according to the fourth aspect of the present invention is a manufacturing method using the support unit for a microfluidic system described in the second aspect. According to the fourth aspect of the present invention, it is possible to provide a manufacturing method of a support unit for a small microfluidic system in which a complicated fluidic circuit can be formed.
BRIEF DESCRIPTION OF DRAWINGS
• FIG. 1 is a cross sectional view of a support unit for a microfluidic system according to a first embodiment of the present invention, andFIG. 1B is a plan view whose cross section along the line I_A-I_Aviewed in the arrow direction corresponds toFIG. 1A.
• FIG. 2 is a process cross sectional view (No. 1) explaining a manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention.
• FIG. 3A is a process cross sectional view (No. 2) explaining the manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention, andFIG. 3B is a plan view whose cross section along the line III_A-III_Aviewed in the arrow direction corresponds toFIG. 3A.
• FIG. 4A is a process cross sectional view (No. 3) explaining the manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention, andFIG. 4B is a plan view whose cross section along the line IV_A-IV_Aviewed in the arrow direction corresponds toFIG. 4A.
• FIG. 5A is a process cross sectional view (No. 4) explaining the manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention, andFIG. 5B is a plan view whose cross section along the line V_A-V_Aviewed in the arrow direction corresponds toFIG. 5A.
• FIG. 6A is a process cross sectional view (No. 5) explaining the manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention, andFIG. 6B is a plan view whose cross section along the line VI_A-VI_Aviewed in the arrow direction corresponds toFIG. 6A.
• FIG. 7A is a process cross sectional view (No. 6) explaining the manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention, andFIG. 7B is a plan view whose cross section along the line VII_A-VII_Aviewed in the arrow direction corresponds toFIG. 7A.
• FIG. 8A is a bird's eye view of a support unit for a microfluidic system including a relay portion according to a second embodiment of the present invention, andFIG. 8B is a cross sectional view along the line VIII_B-VIII_B.
• FIG. 9A is a bird's eye view (No. 1) explaining a configuration of a hollow filament for a support unit for a microfluidic system according to another embodiment of the present invention, andFIG. 9B is a bird's eye view (No. 2) explaining a configuration of a hollow filament for a support unit for a microfluidic system according to another embodiment of the present invention.
• FIG. 10 is a cross sectional view of a support unit for a microfluidic system including a relay portion according to another embodiment of the present invention.
• FIG. 11A is a cross sectional view viewed in the arrow direction along the line XIA-XIA of a plan view of a support unit for a microfluidic system shown inFIG. 11C, according to yet another embodiment of the present invention,FIG. 11B is a cross sectional view viewed in the arrow direction along the line XIB-XIB of the plan view shown inFIG. 11C.
• FIG. 12 is a bird's eye view of the support unit for a microfluidic system according to yet another embodiment of the present invention shown inFIGS. 11A to 11C.
• FIG. 13 is a bird's eye view showing a modification of the support unit for a microfluidic system according to yet another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• Embodiments of the present invention are described with reference to the drawings. The same or similar parts are denoted by the same or similar symbols. However, the drawings are schematic, and a relation between a thickness and a dimension of a plane, a ratio between thicknesses of respective layers, and the like are different from those in reality. Therefore, specific thicknesses and dimensions should be determined by checking the description below. In addition, between the drawings, relationship and ratio between dimensions may of course be different.
First EmbodimentSupport Unit for Microfluidic System
• As shown inFIGS. 1A and 1B, a support unit for a microfluidic system according to a first embodiment of the present invention includes afirst support2, a first adhesive layer1aprovided on a surface of thefirst support2, a first hollow filament group constituted by a plurality ofhollow filaments501,502,503, . . . ,508 laid on a surface of the first adhesive layer to have an arbitrary shape, a second hollow filament group constituted by a plurality ofhollow filaments511,512,513, . . . ,518 laid in a direction intersecting with the first hollow filament group, a second adhesive layer1bprovided on a surface of the second hollow filament group, and asecond support6 provided on a surface of the second adhesive layer1b. The first hollow filament group constituted by the plurality ofhollow filaments501,502,503, . . . ,508 and the second hollow filament group constituted by the plurality ofhollow filaments511,512,513, . . . ,518 respectively configure flow channel layers for a chemical solution, in the support unit for a microfluidic system according to the first embodiment of the present invention.
• The inner diameters and outer diameters of the plurality ofhollow filaments501 to508 and511 to518 may be selected depending on a purpose. However, the inner diameters preferably range from about φ0.05 mm to φ0.5 mm since milliliters (mL) to microliters (μL) of fluid is flown therethrough. In fabricating thehollow filaments501 to508 and511 to518 with the above diameters, particularly suitable materials for the hollow filaments are polyimide (PI), polyether ether ketone (PEEK), polyether imide (PEI), polyphenylene sulfide (PPS), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), and the like. With inner diameters of φ0.05 mm or smaller, an influence of the interface resistance between the fluid and the inner wall surfaces of thehollow filaments501 to508 and511 to518 becomes too great to be ignored. On the other hand, with inner diameters larger than φ0.5 mm, high pressure is required to allow the fluid to flow continuously, thus causing an increase in burdens on other parts and mixing of air bubbles into the fluid. When causing a chemical reaction in the fluid flowing through the first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518, it is preferred that thehollow filaments501 to508 and511 to518 be chemical resistant. Further, when causing a photochemical reaction or performing spectroscopic analysis by illuminating the fluid flowing through thehollow filaments501 to508 and511 to518, it is preferred that thehollow filaments501 to508 and511 to518 be transparent. A value of light transmittance may depend on purpose, but the value is preferably 80% or more with a target wavelength, and the value of 90% or more is optimal. In other words, as shown inFIG. 9A, it is preferred that thesecond support6, the second adhesive layer1b, and ahollow filament58 be transparent at a predetermined position, or that thehollow filament58 be exposed and at least the exposed portion of thehollow filament58 be transparent.
• In comparison with a free state, fixing thehollow filaments501 to508 and511 to518 to thefirst support2 produces an excellent advantage in that various environments around the hollow filaments such as temperature, an electric field, and a magnetic field can be easily controlled. This is advantageous in performing a chemical reaction or chemical analysis, and is particularly essential for micronized reaction system and analysis system. There is another advantage in that thehollow filaments501 to508 and511 to518 are easily aligned with and connected to parts, and a number of thehollow filaments501 to508 and511 to518 can be accommodated compactly.
• Further, when performing chemical analysis, providing the plurality ofhollow filaments501 to508 and511 to518 is advantageous in that operation efficiency is improved. In this case, it is required that the lengths of the plurality ofhollow filaments501 to508 constituting the first hollow filament group are equal to each other from a viewpoint that, when the analysis starts simultaneously in the hollow filaments, results of the analysis should be obtained almost simultaneously. Similarly, it is required that the lengths of the plurality ofhollow filaments511 to518 constituting the second hollow filament group are equal to each other. In other words, it is important that amounts of energy applied from the outside to the inlets through the outlets for a sample are uniform, and that there is little difference between the amounts of energy applied to the hollow filaments. From this viewpoint, it is preferred that thehollow filaments501 to508 and511 to518 be sandwiched by at least two supports so that distribution of heat conducted through thehollow filaments501 to508 and511 to518 is uniform.
• Moreover, it is preferred that the plurality ofhollow filaments501 to508 constituting the first hollow filament group and the plurality ofhollow filaments511 to518 constituting the second hollow filament group be arrayed at mutually equal intervals. Furthermore, it is preferred that the plurality ofhollow filaments501 to508 constituting the first hollow filament group and the plurality ofhollow filaments511 to518 constituting the second hollow filament group have a uniform tube thickness.
• Commercially available tubes made from various materials can be used for the plurality ofhollow filaments501 to508 and511 to518, and tubes made of an arbitrary material may be selected depending on a purpose. These materials include, for example, an organic material such as polyvinyl chloride resin (PVC), polyvinylidene chloride resin, polyvinyl acetate resin, polyvinyl alcohol resin (PVA), polystyrene resin (PS), acrylonitrile butadiene styrene copolymer (ABS), polyethylene resin (PE), ethylene-vinyl acetate copolymer (EVA), polypropylene resin (PP), poly-4-methylpentene (TPX), polymethyl methacrylate (PMMA), PEEK, PI, PEI, PPS, cellulose acetate, polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-hexafluoropropylene resin (FEP), PFA, polyethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoro-ethylene (PCTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate resin (PET), polyamide resin (nylon), polyacetal (POM), polyphenylene terephthalate (PPT), polycarbonate resin (PC), polyurethane resin, polyesterelastomer, polyolefin resin, silicone resin, and polyimide resin, and an inorganic material such as glass, quartz, and carbon.
• Material type, shape and size of thefirst support2 may be selected depending on a purpose. An appropriate range of the board thickness or film thickness of thefirst support2 is differentiated depending on a purpose or a required function. For example, where electrical insulation properties are required in thefirst support2, selected is an epoxy resin board or a polyimide resin board used for a printed wiring board, a polyimide film represented by Kapton film by DuPont Corporation used for a flexible printed wiring board, or a PET film represented by Lumirror Film by Toray Industries Inc. It is preferred that thefirst support2 have a large board thickness (film thickness), and the thickness of 0.05 mm or larger is particularly preferred. Moreover, where heat dissipation properties are required in thefirst support2, a metal board such as an aluminum (Al) board, a copper (Cu) board, a stainless steel board, and a titanium (Ti) board is selected. It is preferred that the thickness of thefirst support2 is even thicker, and the thickness of 0.5 mm or larger is particularly preferred. Further, where light transmittivity is required in thefirst support2, selected is a board made of a transparent inorganic material such as glass and quartz, or a board or film made of a transparent organic material such as polycarbonate and acryl. It is preferred that thefirst support2 has a small board thickness (film thickness), and a thickness of 0.5 mm or smaller is particularly preferred. It is also possible to use so-termed flexible circuit board or printed circuit board in which a metal pattern such as a copper pattern is formed on the surface of thefirst support2 by etching or plating. In virtue of this, it becomes possible to form a terminal or a circuit which implements various parts and elements such as a micromachine, a heater element, a piezoelectric element, various sensors including those of temperature, pressure, distortion, vibration, voltage, magnetic field, and the like, an electronic part such as a resistor, a capacitor, a coil, a transistor, and an IC, and an optical part such as a laser diode (LD), a light emitting diode (LED) and a photodiode (PD). Thus, systemization becomes easy.
• The first adhesive layer1aformed on the surface of thefirst support2 is preferably a pressure sensitive or photosensitive adhesive. These materials realize stickiness or adhesion by application of pressure or light thereto. Therefore, these materials are suitable for the case where the hollow filaments (hollow capillaries) are mechanically laid. As for the pressure sensitive adhesive, a high-molecular weight synthetic rubber adhesive or a silicone resin adhesive is appropriate. The high-molecular weight synthetic rubber may be, for example, polyisobutylene such as Vistanex MML-120 by Tonex Co., Ltd., acrylonitrile-butadiene rubber such as Nipol N1432 by Zeon Corporation, chlorosulfonated polyethylene such asHypalon 20 by DuPont Corporation, and the like. In this case, the first adhesive layer1acan be formed in a manner that these materials are dissolved into a solvent, applied directly onto thefirst support2 and dried. Further, a crosslinking agent may be compounded in these materials as necessary. It is also possible to use a pressure sensitive adhesive double coated tape made of acrylic resin, such as No. 500 by Nitto Denko Corporation, A-10, A-20, A-30 or the like by 3M Corporation, and the like. As for the silicone resin adhesive, a suitable adhesive is a silicone rubber made from high-molecular weight polydimethylsiloxane or polymethylphenylsiloxane and containing terminal silanol groups, or a silicone adhesive whose main ingredient is a silicone resin like a methyl silicone resin or a methylphenyl silicone resin. Various crosslinking can be performed in order to control cohesive strength. For example, crosslinking can be performed by an addition reaction of silane, a condensation reaction of alkoxy, a condensation reaction of acetoxy, and a radical reaction by peroxide or the like. Commercially available adhesives of the above kind include YR3286 (product name, produced by GE Toshiba Silicones Co., Ltd.), TSR1521 (product name, produced by GE Toshiba Silicones Co., Ltd.) DKQ9-9009 (product name, produced by Dow Corning Corporation) and the like. As for the photosensitive adhesive, for example, a dry film resist used as an etching resist of a printed circuit board, a solder resist ink, a photosensitive buildup material of a printed circuit board can be employed. Specifically, H-K440 by Hitachi Chemical Co., Ltd., Probimer by Ciba-Geigy Corporation or the like can be used. Particularly, a photovia material provided for use in a buildup wiring board is durable to a manufacturing process of a printed wiring board and to a process of mounting parts by soldering. Any kind of material can be used as such material as long as it is a copolymer containing functional groups which can be crosslinked by light, or a composition containing monomer, and/or a composition obtained by mixing functional groups which can be crosslinked by heat in stead of light and a thermal polymerization initiator.
• The first adhesive layer1amay be epoxy resin, brominated epoxy resin, cycloaliphatic epoxy resin such as rubber-modified epoxy resin and rubber-dispersed epoxy resin, or bisphenol A epoxy resin and acid modifications of these epoxy resins. Particularly, when photo-curing is performed by illumination, modifications made of these epoxy resins and unsaturated acid are preferred. Unsaturated acid may include maleic anhydride, tetrahydrophthalic anhydride, itaconic acid anhydride, acrylic acid, methacrylic acid, and the like. These modifications are obtained by reacting unsaturated carboxylic acid with epoxy groups of epoxy resin with a compounding ratio in which an amount of unsaturated carboxylic acid is equal to or less than epoxy groups. Apart from the above, a thermosetting material such as melamine resin and cyanate ester resin, or a combination of such thermosetting material and phenolic resin is also a part of favorable application examples. In addition, a combination of such resin and a material which adds flexibility is also favorable. Examples of this include acrylonitrile-butadiene rubber, natural rubber, acrylic rubber, SBR, carboxylic acid-modified acrylonitrile-butadiene rubber, carboxylic acid-modified acrylic rubber, crosslinking NBR particles, carboxylic acid-modified crosslinking NBR particles and the like. By adding various resin components, a curing material can be provided with various properties while maintaining basic properties such as photo-curing and thermosetting. For example, a combination with epoxy resin or phenolic resin can add good electrical insulating properties to a curing material. When a rubber component is compounded, a curing material is provided with toughness, and, at the same time, the surface of the curing material can be roughened easily by surface treatment using an oxidizing chemical solution. Further, additives (polymerization stabilizer, leveling agent, pigment, dye and the like), which are commonly used, may also be added. It is perfectly acceptable to compound a filler. The filler may include inorganic microparticles such as silica, fused silica, talc, alumina, hydrated alumina, barium sulfate, calcium hydroxide, aerosol, and calcium carbonate, organic microparticles such as powdered epoxy resin and powdered polyimide particles, and powdered polytetrafluoroethylene particles. These fillers may be subjected to coupling treatment in advance. Dispersion of these fillers can be achieved by a known mixing method such as a kneader, a ball mill, a bead mill, and a triple-roll mill. A method of forming a photosensitive resin of this kind may be a coating method such as a roll coating, curtain coating and dip coating, and a method of producing films of an insulating resin on a carrier film and sticking the films together by a laminator. Specifically, a photo-via film BF-8000 by Hitachi Chemical Co., Ltd. or the like can be used.
• Earlier-described various materials for thefirst support2 can be used for thesecond support6. Further, the second adhesive layer1bis inserted between thesecond support6 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518. This is preferable since the first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518 are provided with increased protection. By selecting a mesh-like film or a porous film as thesecond support6, a problem such as trapped air bubbles when laminating becomes difficult. This mesh-like film or a fabric may be a polyester mesh TB-70 by Tokyo Screen Co., Ltd. The porous film may be Duragard by Celanese Chemicals, Ltd., Celgard 2400 by Daicel Chemical Industries, Ltd., for example.
• The earlier-described various materials for the first adhesive layer1acan be used for the second adhesive layer1b.
(Manufacturing Method of Support Unit for Microfluidic System)
• Next, a manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention is described usingFIGS. 2 to 8.
• (a) First of all, as shown inFIG. 2, the first adhesive layer1ais formed on the surface of thefirst support2 to have the same shape and approximately the same size as thefirst support2. Then, as shown inFIGS. 3A and 3B, four rectangle release layers3a,3b,3c, and3dare equally faulted on the peripheral portions of the surface of the first adhesive layer1a. These release layers3a,3b,3cand3dare formed on the surface of the first adhesive layer1aby a method of applying a commercially available release agent or sticking release-films to predetermined portions of the surface of the first adhesive layer1a. Next, slits4a,4b,4cand4dare provided in thefirst support2 by a cutter or the like. For example, the slits are made at positions adjacent to the inner lines of the respective fourrelease layers3a,3b,3cand3d.
• (b) Next, as shown inFIGS. 4A and 4B, the first hollow filament group constituted by the plurality ofhollow filaments501 to508 is laid in a vertical direction from therelease layer3btowards therelease layer3d, on the surface of thefirst support2 on which the first adhesive layer1ais formed. Although not illustrated, anNC wiring machine61 similar to that shown inFIG. 5A is used when laying the first hollow filament group. (There is a wiring machine disclosed in Japanese Patent Laid-Open Publication (Kokai) No. 2001-59910 as such a wiring machine. Further, a machine disclosed in Japanese Examined Patent Publication (Kokoku) No. Showa 50 (1975)-9346 can apply a load and ultrasonic vibration while wiring. Furthermore, a machine disclosed in Japanese Examined Patent Publication (Kokoku) No. Heisei 7 (1995)-95622 is capable of applying a load and emitting a laser beam.) TheNC wiring machine61 is numerically controlled and is capable of controlling outputs of ultrasonic vibration and a load. By using thisNC wiring machine61, a laid pattern of the first hollow filament group constituted by the plurality ofhollow filaments501 to508 can be precisely controlled. Specifically, theNC wiring machine61 applies a load and vibration by an ultrasonic wave to the first hollow filament group constituted by thehollow filaments501 to508, while moving in parallel with thefirst support2.
• (c) Next, as shown inFIGS. 5A and 5B, the second hollow filament group constituted by the plurality ofhollow filaments511 to518 is laid in a direction from therelease layer3atowards therelease layer3cintersecting with the first hollow filament group constituted by the plurality ofhollow filaments501 to508 which has already been laid. As shown inFIG. 5A, theNC wiring machine61 is used when laying the second hollow filament group. Thus, a laid pattern of the second hollow filament group constituted by the plurality ofhollow filaments511 to518 can be controlled precisely. Specifically, theNC wiring machine61 applies a load and vibration by an ultrasonic wave to the second hollow filament group constituted by the plurality ofhollow filaments511 to518, while moving in parallel with thefirst support2. However, theNC wiring machine61 is set to stop a load and ultrasonic vibration at the position where the first hollow filament group constituted by thehollow filaments501 to508 and the second hollow filament group constituted by thehollow filaments511 to518 intersect with each other. By stopping a load and/or ultrasonic vibration near the intersection of the first hollow filament group and the second hollow filament group, stress on thehollow filaments501 to508 and511 to518 is reduced, and breakage of thehollow filaments501 to508 and511 to518 can be prevented.
• (d) Next, as shown inFIGS. 6A and 6B, the second adhesive layer1bhaving the same shape and almost the same size as thefirst support2 is formed so as to cover the first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518, which have already been laid. Further, thesecond support6 having the same shape and size as thefirst support2 is prepared and adhered (laminated) onto the second adhesive layer1b. Various methods are considered for laminating thesecond support6. Where thesecond support6 is a mesh-like film or a porous film, this protection film can be closely adhered to the second adhesive layer1bwithout air trapped in the interface, by applying a little pressure. However, where thesecond support6 is a uniform film, there is no way to avoid air bubbles remaining in the interface. In this case, pressing the film with high pressure may be considered, but a large force is applied onto thehollow filaments501 to508 and511 to518 and the hollow portions of the filaments are deformed. Further, there is a problem in that, for example, a large force is locally applied onto the intersection between the first hollow filament group and the second hollow filament group, and the filaments at the intersection are broken. In such a case, it is preferred to use a vacuum laminating machine to create a vacuum state before thesecond support6 is closely adhered to the second adhesive layer1band, thereafter, to press and bond thesecond support6 to the second adhesive layer1bat low pressure. This is because there will be no air trapped in the interface, and a large stress does not remain in thehollow filaments501 to508 and511 to518, causing no breakage of the hollow filaments.
• (e) Thereafter, the support unit is cut along acutting line7 in a desired shape shown by a dotted line inFIG. 7B. A method of making the support unit for a microfluidic system into the desired shape is cutting the support unit by a cutter or cutting the same by pressing a metal blade fabricated to have the desired shape in advance. However, automation of cutting with a cutter is difficult, and, as for the blade, fabrication of jigs takes time and effort. Therefore, it is preferred to use an NC driven laser beam machine as it only requires data preparation to operate. Further, with regard to the laser beam machine, it is preferred to use a laser beam driller for drilling small diameter holes in a printed circuit board rather than a machine with a large output designated for cutting. The laser beam driller for a printed circuit board is preferred since it has a large energy output per unit period, drills a hole by a plurality of shots at the same position, and moves by a measure of about half the diameter of the hole, thus causing the very small number of laser scorches. As shown inFIG. 7B, the support unit is cut along acutting line7 set so as to overlappositions4awhere theslits4a,4b,4cand4dare made in advance. As shown inFIG. 7A, by making theslits4a,4b,4cand4din advance, the first adhesive layer1aand the second adhesive layer1bare automatically peeled off near the end of thehollow filament518. Although not illustrated, at the ends of the otherhollow filaments501 to508,511,512,513, . . . ,517, the first adhesive layer1aand the second adhesive layer1bare similarly peeled off automatically. The first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518 are laid on the first adhesive layer1a. Thereafter, thesecond support6 is adhered to the hollow filaments through the second adhesive layer1b. With this construction, a process of exposing the ends of the plurality ofhollow filaments501 to508 and511 to518 becomes complicated. Therefore, theslits4a,4b,4cand4dare provided in advance at the boundary lines between the portions which are unnecessary and removed ultimately and the portion to remain as thefirst support2, thus facilitating the process of exposing the ends of thehollow filaments501 to518 and511 to518.
• (f) After cutting the support unit along thecutting line7 shown by the dotted line inFIG. 7B, therelease layer3band therelease layer3dpositioned near the ends of thehollow filaments501 to508 are removed, and further, therelease layer3aand therelease layer3cpositioned near the ends of thehollow filaments511 to518 are removed. Thus, the support unit for a microfluidic system shown inFIGS. 1A and 1B is completed.
• As described above, the release layers3a,3b,3cand3dare provided on the surfaces of the ends of thefirst support2 which become unnecessary and are ultimately removed, as shown inFIGS. 4A and 4B. This makes it even easier to carry out the process of drawing out the first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518 respectively from the ends of the support unit for a microfluidic system. However, care should be taken for the lengths of the exposed portions of thehollow filaments501 to508 and511 to518. The reason is as follows. The unexposed portions of thehollow filaments501 to508 and511 to518 are fixed, and it is thus easy to control factors such as temperature, flow velocity distribution, electrophoretic velocity distribution, and applied voltage, of the fluid within thehollow filaments501 to508 and511 to518. Meanwhile, the exposed portions of thehollow filaments501 to508 and511 to518 are not fixed and are in a free state, and it is thus difficult to control each of the above factors. Further, careless handling easily causes breakage of the exposed portions of thehollow filaments501 to508 and511 to518. Therefore, it is important to make the lengths of the exposed portions as short as possible, and it is preferred that the lengths of the exposed portions be at least shorter than the lengths of the unexposed portions.
• Moreover, in the manufacturing method of the support unit for a microfluidic system according to the first embodiment of the present invention, the hollow members (hollow filaments)501 to508 and511 to518 are used. Therefore, appropriate thoughts should be put into design and manufacturing. Apart from the laying conditions on the intersection between the first hollow filament group and the second hollow filament group, there are thoughts put on forming conditions of thesecond support6 serving as a protection film layer. Further, considerations should be made regarding laying conditions of the respective straight portions of the first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518, and curvature conditions on thehollow filaments501 to508 and511 to518. These conditions cannot be set generally since they largely depend on the material of thehollow filaments501 to508 and511 to518 and the specification of the first adhesive layer1a. In other words, it is required to set design and manufacturing conditions suitable for thehollow filaments501 to508 and511 to518 and the first adhesive layer1ato be used. If this operation is neglected, good hollow portions cannot be ensured and, in addition, defects occur in thehollow filaments501 to508 and511 to518, causing incidents such as leakage of a fluid.
Second Embodiment
• As shown inFIGS. 8A and 8b, a support unit for a microfluidic system according to a second embodiment of the present invention is different from the support unit for a microfluidic system according to the first embodiment of the present invention shown inFIGS. 1A and 1B in that the support unit for a microfluidic system according to the second embodiment has anrelay portion8. The first adhesive layer1a, the second adhesive layer1b, and thesecond support6 form the wall portion of therelay portion8, and thefirst support2 is the bottom portion of the same. The rest is similar to the first embodiment, and duplicated description is thus omitted.
• As shown inFIGS. 8A and 8B, therelay portion8 has a construction wherehollow filaments58 are exposed between the first adhesive layer1aand the second adhesive layer1b. The exposedhollow filaments58 discharge a fluid. Therelay portion8 enables the discharged fluid to be mixed or branched. The shape and size of therelay portion8 may be decided depending on the flow quantity of the fluid. For example, where the total thickness of flow channels formed by two or threehollow filaments58 with φ200 μm, and the first adhesive layer1aand the second adhesive layer1b, which hold thehollow filaments58, is 200 μm, therelay portion8 may have a cylindrical shape with about φ2 mm to φ7 mm.
• Laser beam machining is preferred for removal of the first adhesive layer1a, the second adhesive layer1b, and thehollow filaments58 at a predetermined position which becomes therelay portion8. Laser beam machining is particularly preferred where the volume of the removed portion, that is, the volume of therelay portion8 is as small as a volume in cubic millimeters or smaller. A laser used for laser beam machining is a carbon dioxide gas laser, a YAG laser, an excimer laser, and the like, and may be selected depending on the materials of the first adhesive layer1a, the second adhesive layer1b, and thehollow filament58. Note that, where therelay portion8 is formed by a laser, it is preferred to use thefirst support2 with a metal thin film such as a copper or aluminum film formed on the surface thereof. The metal thin film serves as a laser beam stopper. When the volume of therelay portion8 is in cubic centimeters or larger and a large area is thus removed, machining by a drill or the like may be applied. In the case of machining, a desmear treatment for removing resin shavings produced while cutting is added.
• A method of allowing thesecond support6 to be a part of therelay portion8 may be a process of machining thesecond support6 to have a shape so that thesecond support6 becomes a part of therelay portion8. This process is carried out after thesecond support6 is adhered to the second adhesive layer1b. In this case, a method of sticking thesecond support6 by a needle such as an injection needle, or the like, is appropriate.
• Further, another method may be a method of machining thesecond support6 to have a shape so that thesecond support6 becomes a part ofrelay portion8, simultaneously with the formation of therelay portion8 in the first adhesive layer1aand the second adhesive layer1b. In this case, a method of machining the entire layers at once by the foregoing laser, or the like, is appropriate.
• Further, yet another method may be a method of machining thesecond support6 in advance to have a shape so that thesecond support6 becomes a part of therelay portion8, and then adhering thesecond support6 to the second adhesive layer1b. The method of machining thesecond support6 may be drilling, punching, laser beam machining or the like.
• According to the support unit for a microfluidic system according to the second embodiment of the present invention, provision of therelay portion8 makes it possible to mix or branch a fluid flowing through thehollow filaments58. Further, thesecond support6 becomes a part of therelay portion8. Thus, therelay portion8 can have an open structure, enabling a new fluid to be filled into the relay portion from outside and enabling the fluid within therelay portion8 to be removed.
Example 1
• Kapton 300H by DuPont Corporation with a thickness of 75 μm was used as thefirst support2. On the surface of thefirst support2, a VBH A-10 film by 3M Corporation having a thickness of 250 μm and stickiness at room temperature was laminated by a roll laminator as shown inFIG. 2. As shown inFIGS. 3A and 3B, one-sided release paper was provided as the release layers3a,3b,3cand3dat desired positions on thefirst support2 so that the release surfaces were closely adhered to the adhesive surface. Further, as shown inFIGS. 4A and 4B, theslits4a,4b,4cand4dwere made by a cutter at desired positions in thefirst support2. Then, as shown inFIG. 5A, thehollow filaments501 to508 and511 to518 constituted by high-performance engineering plastic tubes by Nirei Industry Co., Ltd. (material: PEEK, inner diameter of 0.2 mm, outer diameter 0.4 mm)62 were laid onto thefirst support2 by using anNC wiring machine61 which is capable of output control of ultrasonic vibration and a load and capable of moving an X-Y table by NC control. A lord of 80 g and vibration by an ultrasonic wave with frequency of 30 kHz were applied to thehollow filaments501 to508 and511 to518 to be laid. As shown inFIG. 5B, thehollow filaments501 to508 and511 to518 were laid to have an arcuate shape with a radius of 5 mm and an intersection therebetween was provided. The load and ultrasonic vibration could be stopped near the intersection. Kapton 300H by DuPont Corporation, on which a VBH A-10 film by 3M Corporation was laminated by the use of a roll laminator, was used as thesecond support6. Thesecond support6 was laminated by a vacuum laminator on the surface of the second filament group constituted by the plurality ofhollow filaments511 to518, as shown inFIGS. 6A and 6B. Thereafter, a laser beam driller for drilling small diameter holes in a printed circuit board was used for machining of the outer shape, and a hole with φ0.2 mm was made at an interval of 0.1 mm with a pulse width of 5 ms and four shots, and the support unit was cut into a wide cross shape along the desiredcutting line7 shown inFIG. 7B. At this time, the support unit was cut so as to overlap the portions where theslits4a,4b,4cand4dhad been respectively made in advance in the positions where the eight hollow filaments in 0.4 mm-pitch were collectively in flat cable shape. Thereafter, the portions of thefirst support2, where the release layers3a,3b,3cand3dhad been stuck near the ends of thehollow filaments501 to508 and511 to518, could be easily removed. Then, a support unit for a microfluidic system was fabricated so that the support unit had a shape where the first hollow filament group constituted by eighthollow filaments501 to508 with an overall length of 20 cm and the second hollow filament group constituted by thehollow filaments511 to518 with an overall length of 20 cm were exposed at their ends, and the length of each exposed end was 10 mm. There was no breakage in the entire portions where the hollow filaments were laid, particularly in the portion where the hollow filaments intersect with each other.
• As a result, variations in positions of the flow channels formed by the first hollow filament group constituted by the plurality ofhollow filaments501 to508 and the second hollow filament group constituted by the plurality ofhollow filaments511 to518 were within +/−10 μm or smaller with reference to a design drawing. The support unit for a microfluidic system was put in a thermoregulator, and the temperature was maintained at 80 degrees centigrade. Liquid color ink was then flown from one ends of the hollow filaments, and duration of time until the ink was flown out were measured by a measurement instrument such as a stopwatch. The ink flew out from the other ends of the eight hollow filaments almost at the same moment (+/−1 second or shorter).
Example 2
• A 0.5 mm-thick aluminum plate was used as thefirst support2. Then, as shown inFIG. 2, a non-stick pressure sensitive adhesive S9009 by Dow Corning Asia Ltd. was laminated onto the surface of the aluminum plate as the first adhesive layer1aby a roll laminator. Further, as shown inFIGS. 3A and 3B, the release layers3a,3b,3cand3dmade of one-sided release paper were provided as films without stickiness onto the surfaces of the portions of the first adhesive layer1a, which were near the ends of the hollow filaments and would be unnecessary. The release layers3a,3b,3cwere provided so that the release surfaces thereof were closely adhered to the adhesive surface. As shown inFIGS. 4A and 4B andFIGS. 5A and 5B, glass tubes ESG-2 by Hagitec Co., Ltd. (inner diameter of 0.8 mm and outer diameter of 1 mm) were laid on the above layers by using theNC wiring machine61 capable of output control of ultrasonic vibration and a load, and capable of moving an X-Y table by NC control. A lord of 100 g and vibration by an ultrasonic wave with frequency of 20 kHz were applied to thehollow filaments501 to508 and511 to518 to be laid. As shown inFIG. 5B, thehollow filaments501 to508 and511 to518 were laid to have an arcuate shape with a radius of 10 mm and an intersection therebetween was provided. The load and an ultrasonic vibration were stopped near the intersection. Kapton 200H by DuPont Corporation, which is the same as the film support, was used as thesecond support6 and laminated by a vacuum laminator on the support unit on which thehollow filaments501 to508 and511 to518 had been laid, as shown inFIGS. 6A and 6B. At this time, thermocouples for temperature measurement were buried near the inlet, outlet and intersection of thehollow filaments501 to508 and511 to518. Thereafter, for machining of the outer shape shown inFIGS. 7A and 7B, the support unit was cut into a desired shape by using an outer shape process machine for a printed circuit board. At this time, the support unit was cut so as to overlap the portions where theslits4a,4b,4cand4dhad been respectively made in the portion where twelve hollow filaments with 1 mm-pitch were collectively in flat cable shape. Thereafter, the portions of the support, where the non-stick films had been stuck near the ends of the plurality ofhollow filaments501 to508 and511 to518, could be easily removed. Then, a support unit for a microfluidic system was fabricated to have a shape where the twelvehollow filaments501 to508 and511 to518 with an overall length of 40 cm were exposed with each exposed portion having a length of 50 mm. Variations in positions of the flow channels formed by thehollow filaments501 to508 and511 to518 were within+/−20 μm or smaller with reference to a design drawing. There was no breakage in the entire portions where the hollow filaments were laid, particularly in the portion where thehollow filaments501 to508 and511 to518 intersect with each other.
• A film heat FTH-40 by Kyohritsu Electronic Industry Co., Ltd. was stuck to the entire back surface of the aluminum plate and temperature was set at 90 degrees centigrade. Water at about 20 degrees centigrade was flown from the one ends of the hollow filaments, and temperature of water flown out from the other ends was measured. The measured temperature was 88+/−1 degrees centigrade. Moreover, temperature at the inlet, outlet and intersection was 89+/−0.5 degrees centigrade, and temperature could be accurately regulated.
Example 3
• As shown inFIGS. 8A and 8B, a copper-clad laminate (plate thickness of 0.2 mm) having 18 μm-thick copper on its surface was used as thefirst support2. On the surface of the copper-clad laminate, a pressure sensitive adhesive S9009 by Dow Corning Asia Ltd. (thickness of 200 μm), which is non-stick at room temperature, was laminated by a roll laminator as the first adhesive layer1aand the second adhesive layer1b. High-performance engineering plastic tubes by Nirei Industry Co., Ltd. (material: PEEK, inner diameter of 0.2 mm, outer diameter of 0.4 mm) were laid by using a wiring machine for multi-wiring, which is capable of output control of ultrasonic vibration and a load and capable of moving an X-Y table by NC control. A load of 80 g and vibration by an ultrasonic wave with frequency of 30 kHz were applied to thehollow filaments58 to be laid. Thehollow filaments58 were laid to have an arcuate shape with a radius of 5 mm and an intersection therebetween was provided. The load and ultrasonic vibration was stopped near the intersection. Kapton 200H by DuPont Corporation, on which S9009 by Dow Corning Asia Ltd. (thickness of 200 μm) was laminated by a roll laminator, was used as thesecond support6. Thesecond support6 was laminated by a vacuum laminator on the surface where thehollow filaments58 were laid.
• Thereafter, a laser beam driller for small diameter holes in a printed circuit board was used with a pulse width of 5 ms and 4 shots to make a hole with φ0.2 mm in thesecond support6, the first adhesive layer1a, the second adhesive layer1band thehollow filaments58, at the position which would be therelay portion8. Thereafter, a router was used to process the outer shape, thus fabricating a support unit for a microfluidic system having therelay portion8 where a plurality of flow channels is connected to each other.
Other Examples
• The present invention has been described based on the foregoing aspects. However, it should be understood that the sections and drawings constituting a part of this disclosure do not limit this invention. Various alternative embodiments, examples and application technologies will be apparent to those skilled in the art from this disclosure.
• For example, as shown inFIG. 9A, a through hole is provided in a part of the support unit for a microfluidic system. The support unit may be used like a micropump or a microvalve which applies a time-periodic force to a part of ahollow filament58 by using a motor with a cam, or the like, to deform the hollow filament at the position where the force is applied, thus moving a fluid at the position and causing pulsating flow. In this case, it is preferred that thehollow filament58 have elasticity. In particular it is preferred that Youngs modulus of thehollow filament58 is 10³MPa or lower.
• Moreover, as shown inFIG. 9B, it is possible to form a metal film59 on a part of the exposedhollow filament58 to form a terminal to which a voltage or the like is applied. In this case, it is preferred that the metal film59 be formed by plating or deposition of a single layered or multi-layered Cu, Al, nickel (Ni), chrome (Cr), gold (Au), or the like.
• Further, as shown inFIGS. 8A and 8B, the support unit for a microfluidic system is provided with therelay portion8 which is an opening portion. However, where therelay portion8 is only for mixing or branching a fluid, therelay portion8 may have a closed structure without removing thesecond support6 as shown inFIG. 10.
• Furthermore, the first hollow filament group and the second hollow filament group do not necessarily intersect with each other at 90 degrees and may only intersect with each other. Therefore, for example, not only the first and second hollow filament groups but also a third hollow filament group may be laid.
• On the other hand, the hollow filaments do not necessarily intersect with each other. As shown inFIGS. 11A to 11C and12, there may be only the first hollow filament group constituted by the plurality ofhollow filaments501 to508 running in one direction.
• Moreover, as shown inFIG. 13, the plurality ofhollow filaments511 to518 with curvatures may be laid.
• Note that the number of the hollow filaments to be laid is not necessarily plural. In other words, the number of the hollow filaments to be laid may be single.
INDUSTRIAL APPLICABILITY
• As described above, according to the present invention, it is possible to provide a support unit for a microfluidic system, which is easily manufactured and has a long flow channel in centimeters that does not limit the number of steps and an amount of a fluid for reaction and analysis.
• As a result, according to the present invention, it is possible to provide a fluidic circuit (a microfluidic system) with good accuracy and fewer manufacturing variations. Further, it is possible to three-dimensionally lay the first hollow filament group constituted by the plurality of hollow filaments and the second hollow filament group constituted by the plurality of hollow filaments, which intersects with the first hollow filament group orthogonally. Thus, a small microfluidic system can be provided even with a complicated flow circuit.
• Moreover, according to the present invention, it is possible to provide a support unit for a microfluidic system in which hollow filaments are arrayed to serve as fluidic channels, and a method of manufacturing such a support unit for a microfluidic system with good accuracy and less manufacturing variations.

Claims (8)

1.-16. (canceled)

17. A manufacturing method of a support unit for a microfluidic system, comprising:

forming a first adhesive layer on a surface of a first support; and

laying a hollow filament on a surface of the first adhesive layer by applying a load and ultrasonic vibration or by applying a load and emitting a laser beam.

18. A manufacturing method of a support unit for a microfluidic system, comprising:

forming a first adhesive layer on a surface of a first support; and

laying a first hollow filament group constituted by a plurality of hollow filaments, on a surface of the first adhesive layer by applying a load and ultrasonic vibration or by applying a load and emitting a laser beam.

19. The manufacturing method of a support unit for a microfluidic system according toclaim 18, between the forming the first adhesive layer and laying the first hollow filament group, the manufacturing method further comprising:

providing release layers on the surface of the first adhesive layer at positions where the hollow filaments are exposed; and

providing a slit in the first support,

wherein the first hollow filament group is laid to be in contact with both surfaces of a pair of the release layers.

20. The manufacturing method of a support unit for a microfluidic system according toclaim 18 or19, further comprising the laying a second hollow filament group constituted by a plurality of hollow filaments in a direction so as to intersect with the first hollow filament group, after the laying the first hollow filament group.

21. The manufacturing method of a support unit for a microfluidic system according toclaim 18 or19, after the laying the first hollow filament group, the manufacturing method further comprising:

forming a second adhesive layer on a surface of the first hollow filament group; and

adhering a second support onto a surface of the second adhesive layer.

22. A manufacturing method of a support unit for a microfluidic system, comprising:

forming a first adhesive layer on a surface of a first support;

laying a plurality of hollow filaments on a surface of the first adhesive layer by applying a load and ultrasonic vibration or by applying a load and emitting a laser beam;

forming a second adhesive layer on the first adhesive layer and the hollow filaments;

forming a relay portion in the first adhesive layer and the second adhesive layer; and

adhering a second support onto a surface of the second adhesive layer.

23. The manufacturing method of a support unit for a microfluidic system according toclaim 22, wherein the forming the relay portion in the first adhesive layer and the second adhesive layer further includes forming the relay portion so that the second support becomes a part of the relay portion.

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