Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K99/00—Subject matter not provided for in other groups of this subclass
  • F16K99/0001—Microvalves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
• • 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
  • B01L3/502738—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 integrated valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15C—FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
  • F15C5/00—Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K13/00—Other constructional types of cut-off apparatus; Arrangements for cutting-off
  • F16K13/08—Arrangements for cutting-off not used
  • F16K13/10—Arrangements for cutting-off not used by means of liquid or granular medium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K99/00—Subject matter not provided for in other groups of this subclass
  • F16K99/0001—Microvalves
  • F16K99/0003—Constructional types of microvalves; Details of the cutting-off member
  • F16K99/0019—Valves using a microdroplet or microbubble as the valve member
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K99/00—Subject matter not provided for in other groups of this subclass
  • F16K99/0001—Microvalves
  • F16K99/0034—Operating means specially adapted for microvalves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K99/00—Subject matter not provided for in other groups of this subclass
  • F16K99/0001—Microvalves
  • F16K99/0034—Operating means specially adapted for microvalves
  • F16K99/0036—Operating means specially adapted for microvalves operated by temperature variations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/00783—Laminate assemblies, i.e. the reactor comprising a stack of plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/00891—Feeding or evacuation
• • 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
  • B01L2200/12—Specific details about manufacturing devices
• • 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
  • B01L2300/0803—Disc shape
  • B01L2300/0806—Standardised forms, e.g. compact disc [CD] format
• • 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
  • B01L2300/18—Means for temperature control
  • B01L2300/1861—Means for temperature control using radiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L2400/00—Moving or stopping fluids
  • B01L2400/06—Valves, specific forms thereof
  • B01L2400/0633—Valves, specific forms thereof with moving parts
  • B01L2400/0661—Valves, specific forms thereof with moving parts shape memory polymer valves

Definitions

• the present invention relates to devices and, methods for controlling liquid flow in micro channel structures.
• micro chamber and channel structures for performing various reactions and analyses have gained wider use.
• Examples of scientific fields employing devices comprising such micro channel structures are separation techniques (gas chromatography, electrophoresis) , cell biology, DNA sequencing, sample preparation, combinatorial chemistry just to mention a few.
• a chamber or cavity may be a part of a microchannel .
• micro chambers In certain applications it is common to provide a plurality of micro chambers in which reactions are performed, or in which material is incubated for later use etc. It may often be desirable to move the material from one chamber to another. To this end the chambers are connected by micro channels . Obviously it may become necessary to provide some means of closing said channels after the material has passed therethrough, and also it might be desirable to have the possibility to reopen the channel in order to enable more material to pass through.
• WO 94/29400 there is disclosed a microfabricated channel system.
• This system is designed for i.a. chemical analytical use, such as electrophoresis and chromatography.
• a channel and/or cavity system is defined between two plane material layers, the recesses which correspond to the channels and cavities, respectively, being formed in one or both of the opposed layer surfaces.
• the layers are usually bonded together by gluing. Alternatively they may be fused together if the two layers consist of thermoplastic material.
• WO 9721090 there is disclosed a microfluidic system having a valve function based on the property of a polymer. Opening of the valve function is actuated by external application of heat.
• the valve function has the drawback that disrupting the heating, e.g. by cooling, will not close the valve.
• the type of systems concerned in the present invention may have channels that are of capillary dimensions for liquid, flow/transport.
• the distance between two opposite walls in a channel may be ⁇ 1000 ⁇ m, such as ⁇ 100 ⁇ m, or even ⁇ 10 ⁇ m, such as ⁇ 1 ⁇ m.
• This type of systems may also contain one or more distinct chambers connected to the channels and having volumes being ⁇ 500 ⁇ l , such as ⁇ 100 ⁇ l and even ⁇ 10 ⁇ l such as 1 ⁇ l .
• the depths of the chambers may typically be in the interval ⁇ 1000 ⁇ m such as ⁇ 100 ⁇ m such as ⁇ 10 ⁇ m or even ⁇ 1 ⁇ m.
• the lower limit for the dimensions is set by manufacturing technology limitations, but can be of the nanometer scale, such as >
• One or more liquid transportation systems of this type may be placed on a common plate, for instance rotatable, such as a disc of CD- type.
• rotatable forms the liquid may be forced through one or more segments of the transportation system by rotating the disc (centripetal force), i.e. the liquid is transported in an outward direction relative the center of the disc.
• centripetal force i.e. the liquid is transported in an outward direction relative the center of the disc.
• Other types of pressure generating systems may also be used.
• a device having one or more liquid transportation system comprising channels and chambers with a depth ⁇ 1000 ⁇ m, such as ⁇ 100 ⁇ m or even grounder than 10 ⁇ m such as ⁇ 1 ⁇ m, are further on called a microfabricated device or a micro chamber and channel structure/system or a microfluidic structure/system.
• the chambers/channels and also the device, structure and system are said to be in the microformat.
• a microfabricated device typically has its channels and chambers in one plane, such as in the surface of a plate, for instance on a disc.
• the plate may be circular, oval, rectangular (including in form of a square) or of any other 2D geometric form.
• the channels and/or chambers define a flow path pattern in the system, which is delineated by barriers.
• the barriers can be in form of physical walls, bottoms and tops that are located on or in a planar surface. Hydrophobic barriers combined with aqueous liquids and vice versa for non-polar liquids (see WO 99/58245) have been suggested for defining flow paths and for directing the liquid flow, i.e. to replace the walls and the like in microfabricated devices.
• Liquid transportation systems of he type referred to above may also contain valves, pumps, filters and the like.
• a chamber and channel structure is provided in or on a plastic disk. Two or more micro chambers in sequence are aligned radially via a channel. When the disk is spun, material in a chamber located near the center will migrate through the channel to an outwardly located chamber, thereby providing a controllable flow path for reagents to pass from one chamber to another .
• One possible use is an automatic gel valve provided in a tube .
• a net is attached to cover the outlet of the tube and a porous PVME (poly (vinyl methyl ether)) gel plug is inserted into the tube and positioned on the ne .
• PVME poly (vinyl methyl ether)
• the gel collapses and the hot water was allowed to freely pass through.
• cold water is introduced, the gel reversibly regains its swollen state, thereby blocking the outlet.
• This concept for a valve function is not possible to apply in a multi-valve structure, since only one gel plug can be inserted in a tube in this way.
• the already introduced plug will hinder the insertion of subsequent plugs downstream. It is also impossible to arrange subsequent plugs upstream of the already positioned plug, since it will be impossible to provide the obstructing net structure for the upstream located plugs .
• the change is reversible meaning that once a stimulus (energy) applied is removed then the polymer returns back to its starting volume.
• energy By applying energy of appropriate type and magnitude it will be possible to cause a volume change in a desired direction (increase or decrease) to either open or close a pathway through a valve comprising this kind of polymer in a microchannel .
• applying energy includes both positive and negative energy values, i.e. removal and supplying energy.
• the required type of energy depends, among others, on the polymer, and includes the so called free energy of chemical systems.
• the application of energy may take place by heating, irradiation (UV, IR etc) etc or by changing the chemical composition of the liquid in contact with the polymer (e.g. change of pH, of solvent, of concentrations of compounds reacting reversible with the polymer etc) .
• externally applied is meant external to the polymer, i.e. application of energy has to take place either via the walls surrounding the polymer or via the liquid in contact with the polymer. This also includes applying the energy to a liquid present in a channel for transport therein by the liquid to the stimulus - responsive polymer in the inventive valve.
• the polymer responds to externally applied heat or to external cooling by undergoing a conformational change.
• the polymer responds to an applied electrical field.
• the polymer responds to light.
• the polymer may in a further embodiment respond to magnetic fields.
• the polymer is provided in gel form (solvated form, closed valve) , disposed inside a channel and retained in a fixed position, or even anchored to at least one surface of said channel.
• gel form solvated form, closed valve
• the polymer When activated, the polymer contracts (the gel collapses or desolvates, opened valve) leaving a free pathway in the channel along that surface or those surfaces to which the polymer is not anchored.
• Fig. 1 shows an example of a micro channel and chamber structure according to WO 94/29400, wherein the invention may be employed;
• Fig. 2 shows a top view of the structure of Fig. 1 in case the microstructure comprises channels and chambers;
• Fig. 3a is a cross section through a channel of a micro channel structure wherein a plug of a stimuli responsive gel is located in a channel, without being anchored to any surface, and in a swollen state;
• Fig. 3b is the same cross section as in Fig. 3a, where the polymer has been stimulated to collapse, thereby providing a free flow path;
• Fig. 3c is a cross section through a channel of a micro channel structure wherein a plug of a stimuli responsive gel is anchored in one surface of the channel, and in a swollen state;
• Fig. 3d is the same cross section as in Fig. 3a, where the polymer has been stimulated to collapse, thereby providing a free flow path;
• Fig. 3e shows a cross section of a channel in which the polymer has been anchored to three surfaces of a channel, and is in a contracted state
• Fig. 4a is a perspective view, partially in cross section of a channel having a grid as a mechanical means to prevent a gel plug from moving;
• Fig. 4b is a perspective view, partially in cross section, of a channel having a plurality of pointed protrusions provided over a surface of a channel, providing anchoring means to prevent a gel plug from moving;
• Fig. 4c is a perspective view, partially in cross section of a channel having side rooms in which a gel plug can be inserted, to prevent it from moving;
• Fig. 5a is microphotograph of the gel prepared in Example 1 in a swollen state;
• Fig. 5b is the same gel as shown in Fig. 5a in contracted state .
• the term "chemical reactor” shall be taken to mean any structure capable of housing chemical and/or biological reagents or reaction partners, and in which these agents can react, i.e. interact with each other, for the purposes of synthesis, analysis, separation or other chemical, physical -chemical or biological processes.
• Fig. 1 there is shown a cross section of a microfabricated channel structure, which forms the subject matter of WO 94/29400.
• the structure in Fig. 1 comprises two elements 11, 12 having opposed plane surfaces bonded together.
• One or both of the surfaces have open channels 14 and or cavities provided therein.
• the bonding may be effected by applying a thin layer 13 of a solution of a material capable of fusing with and having a lower melting point than that of the materials of the two element surfaces, in a solvent which substantially does not dissolve the element surface material or materials. Solvent is removed, the element surface are brought together and heated to melt the layer 3 so as to bond the surfaces together.
• Fig. 2 a top view of a simplified, exemplary CD (compact disk) type of device 21 is shown, having a chamber and channel structure that may be made e.g. in accordance with the disclosure of WO 94/29400.
• the disk comprises two chambers 20 connected via a channel 22.
• an inlet channel 24 having an upward opening (not shown) for the introduction of reagents
• an outlet channel 26 having an opening (not shown) for the discharge of reacted material .
• This particular configuration could be used for e.g. performing a sequential reaction in two steps, one in each chamber 20, the first step being carried out in the innermost (with respect to the radial direction) chamber, and the second in the outermost chamber.
• This structure thus constitutes a "chemical reactor” as defined above, e.g. for carrying out a synthetic reaction.
• a valve function according to the invention is provided in at least the connecting channel 22 and the outlet channel 26. Thereby the second chamber can be isolated from the first, and the reaction in the first chamber can be carried out to the desired extent. Thereafter the valve is activated and the reaction mixture in the first chamber can be transported into the second chamber where new reagents may be present and the second step is carried out .
• the driving force for the transport of material between the chamber can be a centrifugal field created by spinning the disk.
• an electric field would be employed.
• a column like configuration i.e. the chambers are arranged vertically, the first above the second, gravity could be used as driving force for the transport .
• a polymer 34 capable of effecting a structural change in response to a stimulus (stimulus responsive polymer) , is placed in a channel 32 in a channel and chamber micro structure of the type described above. When exposed to said stimulus, the polymer will collapse or contract, and leave at least a fraction of the channel in which it is situated free for liquid to flow there through
• a polymer capable of effecting a structural change in response to a stimulus is anchored in a channel 32 in a channel and chamber micro structure of the type described above.
• the polymer is anchored in such a way that when stimulated to collapse or contract, it has the possibility to leave at least a fraction of the channel in which it is situated free for liquid to flow through.
• the cross section of the channels will be rectangular (see Fig. 3c), that is there will be four walls 31a-d, essentially perpendicular to each other.
• the polymer 34 would preferably be anchored (schematically indicated at 36) to one, two or even three of the walls in said channel. This is shown schematically in Fig.
• FIG. 3c where the polymer is shown to be in its swollen state, thereby blocking the channel completely.
• fig. 3d a situation is shown where the polymer has been stimulated, e.g. by heating, such that it collapses, thereby opening the channel 32 to liquid flow.
• Fig. 3e an embodiment is shown where the polymer gel 34 has been anchored in three walls of a channel. When stimulated by e.g. heat, the polymer strives to contract, but since it is attached to the walls on three sides, it will form a concave upper surface, leaving a free pathway 32 for fluid flow.
• anchoring the polymer available to the skilled man, a couple of which are given as non-limiting examples below.
• the channel surface can be modified to contain reactive groups capable of participating in the polymerization.
• groups can be active as initiators (e.g. azo or peroxide groups), copolymerizable groups (e.g. double bonds) or chain transfer groups (e.g. thiols or tertiary amines) . Examples of ways to introduce the reactive groups are listed below:
• the material in said micro channel surface can be subjected to a variety of surface treatments, such as wet etching, plasma treatment, corona treatment, UV treatment, grafting, adsorption coating, in order to improve the surface properties.
• surface treatments such as wet etching, plasma treatment, corona treatment, UV treatment, grafting, adsorption coating, in order to improve the surface properties.
• the stimulus which can cause a structural change of the polymer in the pores, is selected from pH, ion, solvent composition, chemical substance, heat, electricity and light such as ultraviolet radiation.
• the structural change of polymer is swelling and contraction.
• the invention utilizes the nature of intelligent polymers that an external stimulus can trigger a reversible structural change between a solvated state and a desolvated state.
• an important feature of the polymers used in the valves of the present invention is that they switch from a swelled state (solvated state) to contracted state (desolvated state) or vice versa in a reversible manner as discussed elsewhere herein.
• the state at hand is dependent on the level/intensity of a stimulus applied, meaning for instance that above a certain critical level/intensity (magnitude) of the stimulus one state is at hand.
• the level/intensity typically corresponds to concentrations.
• thermo-responsive polymer having a lower critical solution temperature LCST
• an increase in temperature passing the LCST will cause a switch from the solvated to the desolvated state and vice versa when changing the temperature in the opposite direction.
• UCT upper critical solution temperature
• a polymeric electrolyte gel is known to undergo a structural change owing to an osmotic pressure change by electrolyte ions in the polymer chain and interaction of electrolyte ions with a solvent. Then the polymeric electrolyte gel undergoes reversible contraction in response to a change of pH, solvent composition and ion concentration.
• An electric stimulus (in terms of potential, voltage and current) can be effectively utilized for the polymers contraction response since it can bring a local change of pH or ion concentration.
• non-ionic polymers e.g. polymers and copolymers of vinyl methyl ether and N-isopropylacrylamide undergo a change between hydrophilic and hydrophobic states in response to heat and provide a contraction response in an aqueous solvent. Then by utilizing heat generation by electric resistance or heat of mixing, the effective diameter of the pores can be changed.
• a stimulus given by a chemical substance is such that polymer chains swollen in pores are contracted if a complex is formed by utilizing hydrogen bonds or the like.
• valves according to the invention are provided at selected points in a micro channel system. They can be prepared e.g. by photopolymerizing the stimulus responsive polymer in situ, where the irradiation is made through a mask, such that the polymer is only formed in the illuminated areas. After e.g. heat contraction of the polymer, residual monomers can be washed out of the channel system. It is also conceivable as an alternative to irradiation with light to employ microwaves, electron beams or any other type of radiation that is possible to mask off.
• a further conceivable method is to form the polymer in the entire channel system, and then selectively degrading it (e.g. by light or radiation) everywhere except in the designated areas .
• the degradation products would then be washed out after contraction of the valve areas .
• CD compact disk
• a drop of the monomer solution was transferred to a channel in a microfabricated CD disc made of plastic (polycarbonate) , and covered by a microscope glass cover slip. The monomer solution inside the channel was then illuminated with UV light through the glass cover slip for 10 minutes in order to polymerize the monomers .
• a microscope cover glass was wiped with methacryloxytriethoxysilane and rinsed with water and ethanol .
• a gel-forming solution was prepared from 0.5 g N,N-diethylacrylamide, 10 mg N,N'- methylenebisacrylamide, 6.5 ml distilled water and 0.1 ml of a 0.1 M solution of Irgacure-184 in ethylene glycol .
• a droplet of this solution was placed in a channel of a polycarbonate CD disc having a recessed 100 ⁇ m deep channel pattern on its surface, and a microscope cover glass was placed over the droplet with the treated side facing downwards.
• the package was placed on a cold steel plate under an array of low pressure mercury lamps and illuminated for 5 min to polymerize the monomers.
• a transparent gel was formed in the channels, which turned opaque upon heating to 45°C, and again turned transparent when it was cooled below room temperature.
• An aqueous dye solution was able to penetrate the channel system at 45°C, thus proving that a free path-way for fluid flow was provided.
• the channel was blocked and no dye solution penetrated. The cover glass was then pryed.
• a gel-forming solution was prepared from 0,5 g N,N- diethylacrylamide, 10 mg N,N' -methylenebisacrylamide, 6,5 ml distilled water and 0,1 ml of a o,l M solution of Irgacure-184 in ethylene glycol.
• a droplet of this solution was placed in a channel of a polycarbonate CD disc having a recessed 100 ⁇ m deep channel pattern on its surface, and a microscope cover glass was placed over the droplet .
• the package was placed on a cold steel plate under an array of low pressure mercury lamps and illuminated for 5 min to polymerize the monomers.
• a transparent gel was formed in the channels, which turned opaque upon heating to 45°C, and again turned transparent when it was cooled below room temperature .
• An aqueous dye solution was able to penetrate the channel system at 45°C, thus proving that a free path-way for fluid flow was provided. At room temperature the channel was blocked and no dye solution penetrated.
• thermo-responsive gel was formed only in the illuminated parts of the channel system.
• a micro channel structure in a microfabricated CD disc 40 made of plastic (polycarbonate) is made, having the structure as shown schematically in perspective in Fig. 4.
• mechanical obstructions in the channel 44 at the points where the valve is desired can be in the form of a grid of vertically arranged pins 42, as shown in Fig. 4a which is a cross section through a substrate in which a channel having such obstructions has been made.
• the gel (not shown) is polymerized in the channel upstream of the grid, using the same procedure as in Example 1.
• a hydrostatic pressure using an aqueous dye solution is applied at room temperature to the inlet of the channel. No liquid was seen to flow through the channel.
• the CD disc is then left at 40°C for 5 minutes, and a hydrostatic pressure is again applied to the channel. This time the liquid immediately flowed through the channel.
• the CD disc is then allowed to return to room temperature, and again a hydrostatic pressure is applied. No liquid flowed through the channel.
• Example 6 A micro channel structure in a microfabricated CD disc made of plastic (polycarbonate) is made, having the structure as shown schematically in Fig. 4b.
• mechanical obstructions in the form of protrusions 46 in the channel distributed over the area where the polymer plug is to be located, i.e. at the point where the valve is desired.
• These obstructions can be shaped in the same way as those shown in Fig. 4a, or could be shorter, rather like nipples, as shown in Fig. 4b, and will act as retaining elements for the gel.
• the gel is polymerized (not shown) in the channel in the area where the pins are located, using the same procedure as in Example 1. Thus, the pins will be molded inside the gel plug, thereby preventing it from moving in the channel.
• a hydrostatic pressure using an aqueous dye solution is applied at room temperature to the inlet of the channel. No liquid is seen to flow through the channel.
• the CD disc is then left at 40°C for 5 minutes, and a hydrostatic pressure is again applied to the channel. This time the liquid immediately flowed through the channel.
• the CD disc is then allowed to return to room temperature, and again a hydrostatic pressure is applied. No liquid flowed through the channel.
• a gel plug is provided such that it is “anchored” in the side rooms of the channel 44. If the side rooms are made large enough, the plug will be effectively prevented from moving in the channel under hydrostatic pressure.

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• Engineering & Computer Science (AREA)
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• Mechanical Engineering (AREA)
• Dispersion Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Theoretical Computer Science (AREA)
• Analytical Chemistry (AREA)
• Clinical Laboratory Science (AREA)
• General Health & Medical Sciences (AREA)
• Organic Chemistry (AREA)
• Computer Hardware Design (AREA)
• Hematology (AREA)
• Physics & Mathematics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Fluid Mechanics (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Micromachines (AREA)
• Sampling And Sample Adjustment (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

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• 1999
  • 1999-06-30 SE SE9902474A patent/SE9902474D0/xx unknown
• 2000
  • 2000-06-30 WO PCT/EP2000/006142 patent/WO2001002737A1/en not_active Ceased
  • 2000-06-30 DE DE60007128T patent/DE60007128T2/de not_active Expired - Lifetime
  • 2000-06-30 AU AU59808/00A patent/AU5980800A/en not_active Abandoned
  • 2000-06-30 EP EP00945858A patent/EP1194696B1/en not_active Expired - Lifetime
  • 2000-06-30 AT AT00945858T patent/ATE256254T1/de not_active IP Right Cessation
  • 2000-06-30 US US10/030,297 patent/US7104517B1/en not_active Expired - Lifetime
  • 2000-06-30 JP JP2001507943A patent/JP4323743B2/ja not_active Expired - Lifetime

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