JP2006053064A - Micro-fluid chip and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro-fluid chip capable of feeding or collecting an extremely small amount of a liquid without requiring a special pump or valve. <P>SOLUTION: The micro-fluid chip comprising at least a four-layered structure composed of an opposite surface substrate, a first substrate, a membrane and a second substrate. The first substrate has at least one air passage and the first and second through-holes arranged at both ends of the air passage on the joint surface of the opposite surface substrate. The membrane is constituted so as not only to hermetically close the opening parts of the respective through-holes of the first substrate but also to hold the air passage and the respective through-holes to a vacuum state to form first and second depressed parts depressed in the respective through-holes to respectively correspond to the respective through-holes. The second substrate has at least one microchannel on the joint surface side of the membrane and a port opened toward the atmosphere communicating with the microchannel is arranged at one end of the microchannel while the other end of the microchannel is arranged on the upper surface of the second depressed part 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a microfluidic chip with a microfluidic control mechanism widely used for chemical / biochemical analysis such as gene analysis. More specifically, the present invention relates to a microfluidic chip having a fluid control mechanism capable of collecting a trace amount of sample quantitatively.

  Microstructures such as microchannels, reaction vessels, and ports have been built into the substrate as is known recently under the name of Microscale Total Analysis Systems (μTAS) or Lab-on-Chip (Lab-on-Chip). A microdevice configured to perform various operations such as chemical reaction, synthesis, purification, extraction, generation and / or analysis of a substance within the microstructure has been proposed and partially put into practical use. Structures manufactured for this purpose and having a microstructure such as microchannels, ports and reaction vessels in the substrate are collectively referred to as “microfluidic chips” or simply “microchips”. Microfluidic chips can be used in a wide range of applications such as chemical industry and environmental measurement as well as chemical, biochemical, pharmaceutical, medical, and veterinary fields such as genetic analysis, clinical diagnosis, and drug screening. Compared with the same type of equipment of the common size, the microchip is (1) significantly less sample and reagent usage, (2) shorter analysis time, (3) higher sensitivity, (4) carried on-site, It can be analyzed in the field and (5) can be disposable.

  In the conventional microfluidic chip 100, for example, as shown in FIGS. 12A and 12B, at least one microchannel 102 is formed on a first substrate 101, and an input / output is provided on at least one end of the microchannel 102. Ports 103 and 104 are formed, and a facing substrate 105 is bonded to the lower surface side of the substrate 101. Due to the presence of the facing substrate 105, the ports 103 and 104 and the bottom of the microchannel 102 are sealed. The main uses of the input / output ports 103 and 104 are (a) injection of reagents and specimen samples (dispensing), (b) removal of waste liquid and products, and (c) supply of gas pressure (mainly for liquid feeding (D) Release to the atmosphere (dispersion of internal pressure generated during liquid delivery, release of gas generated by reaction) and (e) Sealing (preventing liquid evaporation and deliberately reducing internal pressure) For the purpose of generating).

  A problem in actual use of the microfluidic chip 100 is that a certain amount of sample necessary for analysis is weighed. For this reason, in such a microfluidic chip, a micropump and / or a microvalve may be arranged in the middle of the microchannel for the purpose of controlling the flow of a continuous liquid and the transfer of microdroplets. . Such micropumps and / or microvalves are described in Patent Document 1 and Patent Document 2, for example.

  The microvalve described in FIG. 1 of Patent Document 1 has a thick first conduit and a diameter smaller than that of the first conduit, and one end communicates with the first conduit. A plurality of connected thin tubes and a second conduit formed so as to be larger in diameter than the thin tube and connected to the other end of the thin tube, and the inner wall of the thin tube is made hydrophobic. It consists of being formed. According to the microvalve, when the liquid is introduced into the first conduit, the first pressure is determined according to the pressure difference between the pressure on the first conduit side and the pressure on the second conduit side with the liquid as a boundary. The position of the liquid in the conduit can be arbitrarily controlled. However, in the microvalve disclosed in Patent Document 1, it is very difficult to form a plurality of capillaries, and there is a risk that the capillaries will be damaged if the pressure difference is too large. In addition, it is very difficult to make only the thin tube portion specifically hydrophobic. Furthermore, the microvalve of the microvalve in Patent Document 1 cannot generate a pressure difference unless a pump is used.

  The microvalve described in FIG. 3 of Patent Document 2 is composed of two polydimethylsiloxane (PDMS) micro-channel chips and one membrane, and the membrane that moves in the valve region operates by attaching and detaching to the valve seat. A valve mechanism for opening and closing the fluid passage; Further, in this microvalve, a driving fluid passage having a pressure chamber in which the pressure of the driving fluid acts in the valve region is formed by bonding to the membrane, and the membrane is obtained by supplying and discharging the pressure of the driving fluid to and from the pressure chamber. Is configured to be opened and closed as a one-way valve by detaching it from the valve seat. However, in the microvalve described in Patent Document 2, since the membrane attached to and detached from the toilet seat is only displaced in one direction toward the pressure chamber, the gap between the membrane and the valve seat when the valve is opened is insufficient. The fluidity of the fluid is low, causing pulsating flow. Further, since the pressure of the driving fluid is supplied from the vacuum pump through the glass pipe, the entire apparatus becomes complicated and expensive.

JP 2000-27813 A Japanese Patent No. 3418727

  Therefore, an object of the present invention is to provide a microfluidic chip capable of feeding or weighing a very small amount of liquid without requiring a special pump or valve.

The means of claim 1 for solving the problem comprises a four-layer structure of a facing substrate, a first substrate, a thin film, and a second substrate,
The first substrate has at least one air passage on the facing substrate bonding surface side, and a first through hole and a second through hole disposed at both ends of the passage,
The thin film seals the opening of each through-hole of the first substrate, and the air passage and each through-hole are kept in a vacuum state, thereby being recessed into each through-hole. Forming a first recess and a second recess,
The second substrate has at least one fine channel on the thin film bonding surface side, and a port opened toward the atmosphere communicating with the fine channel is disposed at one end of the fine channel. The microfluidic chip is characterized in that the other end of the fine channel is disposed on the upper surface of the second recessed portion.

  By adopting the above-described configuration, when a needle or the like is punctured from the outside of the first recessed portion and "vacuum breaks", the air passage and each through hole are recessed when the pressure returns to atmospheric pressure. Since the thin film is restored and a sudden pressure change occurs at that time, the same effect as that of a conventional pump can be exhibited by utilizing this pressure change.

  According to a second aspect of the present invention for solving the above problem, in the microfluidic chip according to the first aspect, the facing substrate is made of glass, and the first substrate, the thin film, and the second substrate are all polydimethyl. A microfluidic chip comprising siloxane (PDMS).

  According to the microfluidic chip of claim 2, when the facing substrate is made of glass, it can be self-adsorbed or permanently bonded to the first PDMS substrate, and the PDMS thin film and each PDMS substrate are also self-adsorbed or permanently bonded. Therefore, high sealing performance can be easily realized.

  According to a third aspect of the present invention, there is provided the microfluidic chip according to the first aspect, wherein at least one microchannel is orthogonal to the at least one microchannel. It is the microfluidic chip characterized.

  According to the microfluidic chip of claim 3, after injecting the liquid sample into one of the microchannels, the other microchannel orthogonal to the microchannels is “breaking the vacuum” as described above, A liquid sample having a volume corresponding to the volume of the intersection portion of the fine channel can be weighed.

According to a fourth aspect of the present invention, there is provided a microfluidic chip manufacturing method comprising: (1) an air passage on one surface and a first through hole on one end of the air passage; Bonding the first substrate having the second through hole at the other end to the facing substrate on the air passage forming surface side;
(2) covering the first and second through holes of the first substrate by covering the upper surface of the first substrate with a thin film;
(3) The three-layer structure of the facing substrate, the first substrate and the thin film is placed in a vacuum chamber, and the air passage sealed in the first substrate and the air in each through hole are exhausted under reduced pressure. Forming a first recessed portion and a second recessed portion at positions corresponding to the first through hole and the second through hole, respectively.
(4) A second substrate having a fine channel on one surface and having a port opened toward the atmosphere at one end of the fine channel is connected to the fine channel. A method of manufacturing a microfluidic chip, comprising a step of bonding on the thin film so that the other end is disposed on an upper surface of the second recessed portion.

  If the first substrate and / or the thin film is formed of a gas permeable material, the air in the sealed air passage and each through hole can be exhausted, whereby a recess is formed in the through hole portion. By forming a needle into the exposed concave part and “breaking the vacuum”, when the air passage and each through hole return to the atmospheric pressure, the concave thin film is restored. Since an abrupt pressure change occurs, the same action as a conventional pump can be exhibited by utilizing this pressure change.

  According to a fifth aspect of the present invention for solving the above problem, in the method of manufacturing a microfluidic chip according to the fourth aspect, the facing substrate is made of glass, and the first substrate, the thin film, and the second substrate are all included. A microfluidic chip comprising polydimethylsiloxane (PDMS).

  6. The method of manufacturing a microfluidic chip according to claim 5, wherein when the first substrate and / or thin film is made of PDMS, PDMS is gas permeable, so that the air in the air passage and the through hole is removed by vacuum suction. Exhaust can be performed, and as a result, a recess can be formed. Further, when the facing substrate is made of glass, it can be self-adsorbed or permanently adhered to the first PDMS substrate, and the PDMS thin film and each PDMS substrate can be self-adsorbed or permanently adhered to each other. It can be easily achieved.

  According to the microfluidic chip of the present invention, a concave portion in a reduced pressure state is provided, and a sharp pressure change is generated by piercing a needle from the outside to “break the vacuum”, thereby causing a pumping action. be able to. As a result, it is possible to perform simple liquid feeding and / or micro liquid weighing without requiring complicated functions such as conventional mechanical or electrical micropumps and valves.

  Hereinafter, preferred embodiments of the microfluidic chip of the present invention will be specifically illustrated with reference to the drawings. FIG. 1A is a schematic plan view of an example of the microfluidic chip of the present invention, and FIG. 1B is a schematic cross-sectional view along the line BB in FIG. 1A. FIG. 2 is a schematic cross-sectional view showing a usage state of the microfluidic chip 1 shown in FIG. 1B. FIG. 3 is a process diagram for explaining an example of a manufacturing method of the microfluidic chip shown in FIG. 1B. FIG. 4 is a schematic plan view of another example of the microfluidic chip of the present invention. 5A and 5B are conceptual plan views showing an example of how to use the microfluidic chip shown in FIG. FIG. 6 is a schematic plan view of still another example of the microfluidic chip of the present invention. 7A and 7B are conceptual plan views showing an example of a method of using the microfluidic chip shown in FIG. FIG. 8 is a schematic plan view of still another example of the microfluidic chip of the present invention. 9A and 9B are conceptual plan views showing an example of how to use the microfluidic chip shown in FIG.

  As shown in FIG. 1A and FIG. 1B, the microfluidic chip 1 of the present invention has a first PDMS substrate 5 attached to the upper surface of a facing substrate 3, and a second PDMS through a PDMS thin film 7. A substrate 9 is laminated. The first PDMS substrate 5 is provided with a first through hole 11 and a second through hole 13, and these through holes are communicated with each other by an air passage 15. Since each through-hole and the inside of the air passage are maintained in a vacuum or a reduced pressure state, the PDMS thin film 7 attached to the upper portion is recessed so as to be drawn inside at the through-hole portion, and the first recessed portion 17 And a second recessed portion 19 is formed. A liquid sample 21 to be fed is placed in the second recess 19. Since PDMS is hydrophobic, the capillary phenomenon does not occur. Therefore, the liquid sample 21 accommodated in the second recessed portion 19 does not flow into the fine channel 23 but remains in the second recessed portion 19 as it is. A second PDMS substrate 9 is laminated so as to cover the second recessed portion 19. The second PDMS substrate 9 is provided with a fine flow path 23 and a port 25 opening toward the atmosphere. One end of the fine channel 23 communicates with the port 25. The other end of the microchannel 23 has an enlarged portion 27 whose diameter is increased so as to have an area necessary and sufficient to cover the second recessed portion 19. The size of the enlarged portion 27 may be smaller than that of the second recessed portion 19. An advantage of providing the enlarged portion 27 is that positioning of the second PDMS substrate 9 is facilitated. However, providing the enlarged portion 27 at the other end of the fine channel 23 is not an essential requirement of the present invention. Even if the other end having the normal width and height of the fine channel 23 is disposed on the upper surface of the second recessed portion 19, the effect of the present invention can be sufficiently achieved. When the enlarged portion 27 is smaller than the second recessed portion 19 or when the enlarged portion 27 is not provided, there is an advantage that the pressure change becomes sharper.

  FIG. 2 is a schematic cross-sectional view showing a usage state of the microfluidic chip 1 shown in FIG. 1B. When the vacuum in each through hole and air passage is released by piercing a needle or the like from the outside of the first recessed portion 17, the PDMS thin film 7 returns to the original flat state. At that time, the liquid sample 21 accommodated in the second recessed portion 19 is pressurized and fed into the fine channel 23. According to such “vacuum breaking”, the pressure change becomes sharp, and the liquid can be fed without using a special pump. Although the liquid sample 21 in the microchannel 23 can be taken out from the port 25, it can be taken out from another port through another microchannel as will be described later. When the other end of the fine channel is not provided with the enlarged portion 27 and the other end of the normal width and height is arranged on the upper surface of the second recessed portion 19 and "vacuum breaks", the pressure change becomes sharper. The advantage of becoming.

  Next, a manufacturing method of the microfluidic chip shown in FIG. 1 will be described with reference to FIG. As shown in FIG. 3A, a member in which the first PDMS substrate 5 is attached to the facing substrate 3 is prepared. An air passage 15, a first through hole 11, and a second through hole 13 are formed in the first PDMS substrate 5. These air passages can be formed by a conventional photolithographic method, and the photolithographic method itself is known to those skilled in the art and need not be described in particular. Each through hole can be formed by mechanical drilling or punching means. The inner diameter of each through-hole can be the same or different. For example, the inner diameter of the second through hole 13 can be made larger than the inner diameter of the first through hole 11. In particular, the inner diameter of the second through hole 13 can be appropriately determined in consideration of the volume of the liquid sample 21 to be placed later. For example, it is about several hundred μm to several mm. The width and height of the air passage 15 can be selected as appropriate. As an example, it is about several μm to several hundred μm. The thickness of the first PDMS substrate 5 is about several hundred μm to several mm, and the thickness of the facing substrate 3 is also about several hundred μm to several mm. Any material can be used as the material of the facing substrate 3 as long as the material can be in close contact with the first PDMS substrate 5 such as glass or plastic. However, the material of the facing substrate 3 is preferably glass that can be permanently bonded to PDMS.

  Next, as shown in FIG. 3B, a PDMS thin film 7 is attached to the upper surface of the first PDMS substrate 5. PDMS has the property of being permanently bonded. Permanent adhesion is a property that allows PDMSs to adhere to each other without an adhesive by surface modification under an atmosphere such as oxygen plasma, and excellent adhesion or adhesion between PDMSs. Can be demonstrated. The film thickness of the PDMS thin film 7 is about several μm to several tens of μm. If it is too thin, there is a risk of breakage in the vacuum suction process described later, which is not preferable. On the other hand, if it is too thick, it not only hinders vacuum suction, but also has the disadvantage that the repulsive force when “breaking the vacuum” is weak and the pressure change does not become sharp. However, the thin film 7 can be a material other than PDMS as long as it has characteristics such as flexibility, stretchability, hydrophobicity, and gas permeability.

  Thereafter, the member obtained in the step (B) is placed in the vacuum chamber 30 and vacuumed to bring the vacuum chamber 30 into a reduced pressure state. As shown in FIG. 3 (C-1), the PDMS thin film 7 initially expands because it is exposed to a reduced-pressure atmosphere. However, since PDMS is very slight but has gas permeability, air in the sealed space between the through holes 11 and 13 and the air passage 15 is removed through the PDMS thin film 7. Thereafter, by releasing the vacuum in the vacuum chamber 30, the PDMS thin film 7 is recessed, and the inside of the sealed space between the through holes 11 and 13 and the air passage 15 is in a reduced pressure state. As a result, as shown in FIG. 3 (C-2), the PDMS thin film 7 is sucked into the through holes 11 and 13, and a first concave portion 17 and a second concave portion 19 are formed. The volume of the recess can be changed by adjusting the evacuation time. The maximum volume of the recessed portion is the time when the volume of the through hole is substantially the same.

  Next, the member in which the recessed portion is formed is taken out from the vacuum chamber 30. After removal, a predetermined volume of the liquid sample 21 is injected into the second recessed portion 19 to form a member as shown in FIG. The injection volume of the liquid sample 21 is preferably determined in consideration of the volume of the fine flow path 23 and the port 25 of the second PDMS substrate 9 stacked in a later process.

  Thereafter, as shown in FIG. 3E, the second PDMS substrate 9 is laminated so as to cover the second recessed portion 19. Thus, the microfluidic chip 1 of the present invention shown in FIG. 1 is obtained. Similar to the first PDMS substrate 5, the second PDMS substrate 9 can also be permanently bonded to the PDMS thin film 7. The fine flow path 23 and the port 25 of the second PDMS substrate 9 can be formed by the same photolithography method as the air passage 15 and the through holes 11 and 13 of the first PDMS substrate 5. The thickness of the second PDMS substrate 9 is about several hundred μm to several mm. The width and height of the fine channel 23 of the second PDMS substrate 9 are about several tens of μm to several hundreds of μm, and the inner diameter of the port 25 is about several hundreds of μm to several mm. The sizes of the microchannel 23 and the port 25 can be determined in consideration of the volume of the liquid sample 21 injected into the second recessed portion 19. The second substrate 9 can also be formed from plastic other than PDMS, glass, ceramic, or the like.

FIG. 4 is a schematic plan view of another example of the microfluidic chip of the present invention. In the microfluidic chip 1A shown in FIG. 4, two microchannels are arranged so as to be orthogonal to each other, and a liquid sample having a volume corresponding to the volume of the intersection of the microchannels can be collected quantitatively.
The microfluidic chip 1A shown in FIG. 4 basically has a cross-sectional structure similar to the four-layer structure shown in FIG. 1B. Specifically, the microfluidic chip 1A has a first concave portion 17A and a second concave portion 19A communicated by an air passage 15A, a first microchannel 23A, A first port 25A that opens to the atmosphere is disposed at one end of the microchannel 23A, and the other end of the first microchannel 23A is necessary and sufficient to cover the second recessed portion 19A. A first enlarged portion 27A having a large diameter is disposed. A liquid sample 21 to be fed is placed in the second recessed portion 19A. Furthermore, it has the 3rd recessed part 17B and the 4th recessed part 19B which were connected by the air path 15B, and also has the 2nd fine flow path 23B, and one end of the 2nd fine flow path 23B has A second port 25B that opens to the atmosphere is provided, and the other end of the second microchannel 23B is expanded to have an area sufficient to cover the fourth recessed portion 19B. A second enlarged portion 27B is provided. However, it remains a blank where nothing is injected into the fourth recess 19B. The first microchannel 23A and the second microchannel 25B intersect at a right angle in the same plane and communicate with each other at an intersection 32.

  5A and 5B are conceptual plan views showing an example of how to use the microfluidic chip shown in FIG. In FIG. 5A, when the vacuum is released by piercing a needle or the like from the outside of the first concave portion 17A, the PDMS thin film 7 corresponding to the first concave portion 17A and the second concave portion 19A is flat. Return to state. At that time, the pressure in the first enlarged portion 27A rapidly increases, and the liquid sample 21 accommodated in the second recessed portion 19A is pressurized and fed into the first fine channel 23A. Next, in FIG. 5B, when the vacuum is released by piercing a needle or the like from the outside of the third recessed portion 17B, the PDMS thin film 7 corresponding to the third recessed portion 17B and the fourth recessed portion 19B becomes the original. Return to the flat state. At that time, since the pressure in the second enlarged portion 27B rapidly increases and the pressure propagates toward the second port 25B, the intersection 32 between the first microchannel 23A and the second microchannel 23B. A portion of the liquid sample 21 is pressurized and fed to the second port 25B via the second fine channel 23B. Thus, the very small volume of the liquid sample 21 corresponding to the volume of the intersection 32 portion between the first microchannel 23A and the second microchannel 23B is accurately weighed and taken out from the second port 25B. be able to.

FIG. 6 is a schematic plan view of still another example of the microfluidic chip of the present invention. In the microfluidic chip 1 </ b> B shown in FIG. 6, a plurality of microchannels are arranged so as to be orthogonal to the first microchannel. As a result, a plurality of intersection portions are also formed, so that a plurality of liquid samples having a volume corresponding to the volume of each intersection portion of the fine channel can be quantitatively collected.
The microfluidic chip 1B shown in FIG. 6 basically has a cross-sectional structure similar to the four-layer structure shown in FIG. 1B. Specifically, the microfluidic chip 1B includes a first concave portion 17A and a second concave portion 19A communicated by an air passage 15A, a first microchannel 23A, A first port 25A that opens to the atmosphere is disposed at one end of the microchannel 23A, and the other end of the first microchannel 23A is necessary and sufficient to cover the second recessed portion 19A. A first enlarged portion 27A having a large diameter is disposed. A liquid sample 21 to be fed is placed in the second recessed portion 19A. Furthermore, it has the 3rd recessed part 17B and the 4th recessed part 19B which were connected by the air path 15B, and also has the 2nd fine flow path 23B, and one end of the 2nd fine flow path 23B has A second port 25B that opens to the atmosphere is provided, and the other end of the second microchannel 23B is expanded to have an area sufficient to cover the fourth recessed portion 19B. A second enlarged portion 27B is provided. However, it remains a blank where nothing is injected into the fourth recess 19B. The first microchannel 23A and the second microchannel 23B intersect at a right angle in the same plane and communicate with each other at an intersection 32-1. Each member of 15C to 27C is arranged in parallel with each member of 15B to 27B. That is, it has the 5th recessed part 17C and the 6th recessed part 19C which were connected by 15 C of air passages, and also has the 3rd fine flow path 23C, and the end of the 3rd fine flow path 23C has A third port 25C that is open to the atmosphere is disposed, and the other end of the third microchannel 23C is expanded to have an area sufficient to cover the sixth recessed portion 19C. A third enlarged portion 27C is provided. However, it remains a blank where nothing is injected into the sixth recessed portion 19C. The first microchannel 23A and the third microchannel 23C intersect at a right angle in the same plane and communicate with each other at an intersection 32-2.

  Similar to the embodiment described with reference to FIGS. 5A and 5B, in FIG. 7A, when the vacuum is released by piercing a needle or the like from the outside of the first recess 17A, the first recess 17A and the second recess The portion of the PDMS thin film 7 corresponding to the recessed portion 19A returns to the original flat state. At that time, the pressure in the first enlarged portion 27A rapidly increases, and the liquid sample 21 accommodated in the second recessed portion 19A is pressurized and fed into the first fine channel 23A. Next, in FIG. 7B, when the vacuum is released by piercing a needle or the like from the outside of the third concave portion 17B and the fifth concave portion 17C, the third concave portion 17B, the fourth concave portion 19B, and the fifth concave portion 17B The portions of the PDMS thin film 7 corresponding to the recessed portions 17C and the sixth recessed portion 19C return to the original flat state. At that time, the pressure in the second enlarged portion 27B and the third enlarged portion 27C increases rapidly, and the pressure propagates toward the second port 25B and the third port 25C. The liquid sample 21 at the intersection 32-1 portion of 23A and the second microchannel 23B and at the intersection 32-2 portion of the first microchannel 23A and the third microchannel 23C is the second microstream. The liquid is pressurized and fed to the second port 25B and the third port 25C through the path 23B and the third fine flow path 23C. Thus, at the intersection 32-1 portion between the first microchannel 23A and the second microchannel 23B and at the intersection 32-2 portion between the first microchannel 23A and the third microchannel 23C. A very small volume of the liquid sample 21 corresponding to the volume can be accurately weighed and taken out from the second port 25B and the third port 25C. By increasing the number of sampling microchannels 23B to 23C perpendicular to the microchannel 23A for supplying the liquid sample, a larger number of samples can be individually weighed.

FIG. 8 is a schematic plan view of still another example of the microfluidic chip of the present invention. In the microfluidic chip 1C shown in FIG. 8, a plurality of liquid sample weighing microchannels are arranged orthogonal to the first microchannel and the second microchannel for supplying a liquid sample. It is installed. As a result, a plurality of intersection portions are also formed, so that a plurality of liquid samples having a volume corresponding to the volume of each intersection portion of the fine channel can be quantitatively collected in a mixed state.
The microfluidic chip 1C in FIG. 8 basically has a cross-sectional structure similar to the four-layer structure shown in FIG. 1B. Specifically, the microfluidic chip 1C includes a first concave portion 17A and a second concave portion 19A communicated by an air passage 15A, a first microchannel 23A, and a first microchannel 23A. A first port 25A that opens to the atmosphere is disposed at one end of the microchannel 23A, and the other end of the first microchannel 23A is necessary and sufficient to cover the second recessed portion 19A. A first enlarged portion 27A having a large diameter is disposed. A first liquid sample 21A to be fed is placed in the second recessed portion 19A. Further, in parallel with the air passage 15A, the third concave portion 17B and the fourth concave portion 19B communicated by the air passage 15B, the second fine flow path 23B, and the second fine passage 23B are provided. A second port 25B opened toward the atmosphere is disposed at one end of the flow path 23B, and the other end of the second fine flow path 23B has an area necessary and sufficient to cover the fourth recessed portion 19B. A second enlarged portion 27 </ b> B that is enlarged to have a diameter is disposed. A second liquid sample 21B to be fed is placed in the fourth recess 19B. A third microchannel 23C and a fourth microchannel 23D are disposed so as to be orthogonal to the first microchannel 23A and the second microchannel 23B. That is, the third microchannel 23C intersects the first microchannel 23A at the intersection 32-1A, and intersects the second microchannel 23B at the intersection 32-1B. Similarly, the fourth microchannel 23D intersects the first microchannel 23A at the intersection 32-2A and intersects the second microchannel 23B at the intersection 32-2B. A third port 25C that opens to the atmosphere is disposed at one end of the third fine channel 23C, and a third enlarged portion 27C is disposed at the other end. A sixth recessed portion 19C having a diameter smaller than the diameter of the expanded portion is present below the third expanded portion 27C, and the sixth recessed portion 19C communicates with the third air passage 15C. The recessed portion 17C is disposed. Similarly, a fourth port 25D that opens toward the atmosphere is disposed at one end of the fourth microchannel 23D, and a fourth enlarged portion 27D is disposed at the other end. An eighth recessed portion 19D having a diameter smaller than the diameter of the expanded portion is present below the fourth expanded portion 27D, and the eighth recessed portion 19D is in communication with the fourth air passage 15D. The recessed portion 17D is disposed. In the sixth recessed portion 19C and the eighth recessed portion 19D, nothing is injected into the blank.

  Similar to the embodiment described with reference to FIGS. 5A and 5B, in FIG. 9A, when the vacuum is released by piercing a needle or the like from the outside of the first recess 17A, the first recess 17A and the second recess The portion of the PDMS thin film 7 corresponding to the recessed portion 19A returns to the original flat state. At that time, the pressure in the first enlarged portion 27A rapidly increases, and the first liquid sample 21A accommodated in the second recessed portion 19A is pressurized and fed into the first microchannel 23A. . Similarly, when the vacuum is released by piercing a needle or the like from the outside of the third concave portion 17B, the PDMS thin film 7 corresponding to the third concave portion 17B and the fourth concave portion 19B is in an original flat state. Return to. At that time, the pressure in the second enlarged portion 27B rapidly increases, and the second liquid sample 21B accommodated in the fourth recessed portion 19B is pressurized and fed into the second microchannel 23B. . Next, in FIG. 9B, when the vacuum is released by piercing a needle or the like from the outside of the fifth concave portion 17C, the PDMS thin film 7 corresponding to the fifth concave portion 17C and the sixth concave portion 19C becomes the original. Return to the flat state. At this time, since the pressure in the third enlarged portion 27C rapidly increases and the pressure propagates toward the third port 25C, the first liquid at the intersection 32-1A portion with the first fine channel 23A. The second liquid sample 21B at the intersection 32-1B between the sample 21A and the second microchannel 23B is pressurized and fed to the third port 25C in a mixed state via the third microchannel 23C. The Thus, the first liquid sample 21A and the second liquid sample having a very small volume corresponding to the volumes of the intersection 32-1A portion of the first microchannel 23A and the intersection 32-1B portion of the second microchannel 23B. The liquid sample 21B can be accurately weighed and taken out from the third port 25C in a uniformly mixed state. When the puncturing process is performed on the seventh recessed portion 17D in the same manner as described above, the intersection 32-2A portion of the first microchannel 23A and the intersection 32-2B portion of the second microchannel 23B are similarly performed. The first liquid sample 21A and the second liquid sample 21B having a very small volume corresponding to the volume of the liquid can be accurately weighed and taken out from the fourth port 25D in a uniformly mixed state.

FIG. 10 is a schematic plan view of still another example of the microfluidic chip of the present invention. In the microfluidic chip 1D shown in FIG. 10, since the ports opened toward the atmosphere are formed at both ends of the first fine channel, the liquid sample is injected from one port toward the other port. Thus, the liquid sample can be filled in the first fine channel. Further, a plurality of fine channels are arranged so as to be orthogonal to the first fine channel. As a result, a plurality of intersection portions are also formed, so that a plurality of liquid samples having a volume corresponding to the volume of each intersection portion of the fine channel can be quantitatively collected.
The microfluidic chip 1D shown in FIG. 10 basically has a cross-sectional structure similar to the four-layer structure shown in FIG. 1B. Specifically, the microfluidic chip 1D has a first microchannel 23A in which a first port 25A and a fifth port 25E that are open toward the atmosphere are disposed at each end. Furthermore, it has the 3rd recessed part 17B and the 4th recessed part 19B which were connected by the air path 15B, and also has the 2nd fine flow path 23B, and one end of the 2nd fine flow path 23B has A second port 25B that opens to the atmosphere is provided, and the other end of the second microchannel 23B is expanded to have an area sufficient to cover the fourth recessed portion 19B. A second enlarged portion 27B is provided. However, it remains a blank where nothing is injected into the fourth recess 19B. The first microchannel 23A and the second microchannel 23B intersect at a right angle in the same plane and communicate with each other at an intersection 32-1. Each member of 15C to 27C is arranged in parallel with each member of 15B to 27B. That is, it has the 5th recessed part 17C and the 6th recessed part 19C which were connected by 15 C of air passages, and also has the 3rd fine flow path 23C, and the end of the 3rd fine flow path 23C has A third port 25C that is open to the atmosphere is disposed, and the other end of the third microchannel 23C is expanded to have an area sufficient to cover the sixth recessed portion 19C. A third enlarged portion 27C is provided. However, it remains a blank where nothing is injected into the sixth recessed portion 19C. The first microchannel 23A and the third microchannel 23C intersect at a right angle in the same plane and communicate with each other at an intersection 32-2.

  In FIG. 11A, the liquid sample 21 can be filled in the first microchannel 23A by injecting the liquid sample 21 from the first port 25A toward the fifth port 25E. For example, the liquid sample 21 is injected by connecting a tube (not shown) to the first port 25A, connecting a syringe (not shown) to the other end of the tube, and feeding the liquid sample 21 from this syringe. This can be done. The microfluidic chip of this embodiment has an advantage that the liquid sample 21 can be easily supplied as compared with the microfluidic chip of the embodiment shown in FIG. 4, FIG. 6, or FIG.

  Next, in FIG. 11B, when the vacuum is released by piercing a needle or the like from the outside of the third concave portion 17B and the fifth concave portion 17C, the third concave portion 17B, the fourth concave portion 19B, and the fifth concave portion 17B The portions of the PDMS thin film 7 corresponding to the recessed portions 17C and the sixth recessed portion 19C return to the original flat state. At that time, the pressure in the second enlarged portion 27B and the third enlarged portion 27C increases rapidly, and the pressure propagates toward the second port 25B and the third port 25C. The liquid sample 21 at the intersection 32-1 portion of 23A and the second microchannel 23B and at the intersection 32-2 portion of the first microchannel 23A and the third microchannel 23C is the second microstream. The liquid is pressurized and fed to the second port 25B and the third port 25C through the path 23B and the third fine flow path 23C. Thus, at the intersection 32-1 portion between the first microchannel 23A and the second microchannel 23B and at the intersection 32-2 portion between the first microchannel 23A and the third microchannel 23C. A very small volume of the liquid sample 21 corresponding to the volume can be accurately weighed and taken out from the second port 25B and the third port 25C. By increasing the number of sampling microchannels 23B to 23C perpendicular to the microchannel 23A for supplying the liquid sample, a larger number of samples can be individually weighed.

  The number of fine flow paths having open ports at both ends for supplying a liquid sample is not limited to one, and two or more fine flow paths can be provided. In this case, similarly to the microfluidic chip of the embodiment of FIG. 8, a plurality of types of liquid samples can be quantitatively mixed and weighed.

A four-layer microfluidic device of the present invention was fabricated. The facing substrate 3 is made of white glass having a thickness of 1 mm, the first PDMS substrate 5 is made of silicone rubber having a thickness of 2 mm, the PDMS thin film 7 is made of silicone rubber having a thickness of 40 μm, 2 PDMS substrate 9 was made of silicone rubber having a thickness of 2 mm. The air passage 15 disposed in the first PDMS substrate 5 has a width of 200 μm, a depth of 100 μm, and a length of 20 mm. The inner diameter of each of the first through hole 11 and the second through hole 13 is φ4 mm. Met. The microchannel 23 disposed on the second PDMS substrate 9 has a width of 200 μm, a depth of 200 μm, and a length of 20 mm. The diameter of the enlarged portion 27 provided at one end of the microchannel 23 is The inner diameter of the port 25 provided at the other end of the fine channel 23 was φ2 mm.
In forming the air passage 15, a thick film resist was patterned on the wafer by photolithography (exposure and development), and used as a mold for a silicone rubber mold. Before forming the silicone rubber mold, a 20 nm CHF ₃ film was formed on the mold as a release film, and then the silicone rubber was molded and deaerated. Thereafter, the silicone rubber was polymerized by heating at 100 ° C. for 4 hours. Thereafter, the first PDMS substrate 5 having the air passage 5 is formed by peeling off from the mold, and then the first PDMS substrate 5 is permanently bonded to the facing substrate 3 made of white glass, and then the first PDMS A first through hole 11 and a second through hole 13 were mechanically drilled in the substrate 5. Thereafter, the PDMS thin film 7 formed in advance was self-adsorbed on the upper surface of the first PDMS substrate 5.
Next, the three-layer structure obtained as described above is accommodated in a vacuum chamber, and after the vacuum chamber is sealed, the air in the vacuum chamber is exhausted by a vacuum pump, and the pressure in the vacuum chamber is 0.1 MPa. And the pressure was maintained for 20 minutes. As a result, the first concave portion 17 and the second concave portion 19 corresponding to the positions of the first through hole 11 and the second through hole 13 were formed. Then, after returning the pressure in a vacuum chamber to atmospheric pressure, the three-layer structure in which the recessed part was formed was picked out from the vacuum chamber.
After injecting 5 μL of colored ink as the liquid sample 21 into the second recessed portion 19, the second PDMS substrate 9 is placed on the upper surface of the PDMS thin film 7 so that the enlarged portion 27 covers the second recessed portion 19. Adsorbed. Formation of the fine flow path 23, the enlarged portion 27, and the port 25 in the second PDMS substrate 9 was performed by the same method as the formation method of the air passage 15 and the through holes 11 and 13 in the first PDMS substrate 5.
In the microfluidic chip 1 having the four-layer structure obtained as described above, a needle was pierced from the outer surface side of the first recessed portion 17 to break the vacuum. Then, the PDMS thin film 7 is restored, the first concave portion 17 and the second concave portion 19 disappear and become flat, and the colored ink 21 in the second concave portion 19 passes through the fine channel 23. The solution was sent to port 25.

  Although preferred embodiments of the present invention have been described above, the present invention is not limited to only the illustrated embodiments. For example, the liquid feeding mechanism by vacuum breakage of the vacuum recess of the present invention can be used not only in a microfluidic chip but also in a microfluidic control mechanism in various fields.

It is a general | schematic top view of an example of the microfluidic chip | tip of this invention. It is a schematic sectional drawing in alignment with the BB line in FIG. 1A. 1B is a schematic cross-sectional view showing a usage state of the microfluidic chip 1 shown in FIG. 1B. FIG. It is process drawing explaining an example of the manufacturing method of the microfluidic chip | tip shown by FIG. 1B. It is a general | schematic top view of another example of the microfluidic chip | tip of this invention. FIG. 5 is a conceptual plan view illustrating an example of a method for using the microfluidic chip illustrated in FIG. 4. FIG. 5 is a conceptual plan view illustrating an example of a method for using the microfluidic chip illustrated in FIG. 4. It is a general | schematic top view of another example of the microfluidic chip | tip of this invention. FIG. 7 is a conceptual plan view showing an example of how to use the microfluidic chip shown in FIG. 6. FIG. 7 is a conceptual plan view showing an example of how to use the microfluidic chip shown in FIG. 6. FIG. 10 is a schematic plan view of still another example of the microfluidic chip of the present invention. FIG. 9 is a conceptual plan view illustrating an example of a method for using the microfluidic chip illustrated in FIG. 8. FIG. 9 is a conceptual plan view illustrating an example of a method for using the microfluidic chip illustrated in FIG. 8. FIG. 10 is a schematic plan view of still another example of the microfluidic chip of the present invention. It is a conceptual top view which shows an example of the usage method of the microfluidic chip | tip shown by FIG. It is a conceptual top view which shows an example of the usage method of the microfluidic chip | tip shown by FIG. (A) is an outline top view of an example of the conventional microfluidic chip, and (B) is an outline sectional view which met a BB line in (A).

Explanation of symbols

1, 1A, 1B, 1C, 1D Microfluidic chip of the present invention 3 Face-to-face substrate 5 First PDMS substrate 7 PDMS thin film 9 Second PDMS substrate 11 First through hole 13 Second through hole 15 Air passage 15A First 1 air passage 15B 2nd air passage 15C 3rd air passage 15D 4th air passage 17, 17A 1st recessed part 19, 19A 2nd recessed part 17B 3rd recessed part 17C 5th recessed part 17D 7th recessed part 19B 4th recessed part 19C 6th recessed part 19D 8th recessed part 21,21A, 21B Liquid sample 23 Microchannel 23A 1st microchannel 23B 2nd microchannel 23C 3rd microchannel 23D 4th microchannel 25A 1st port 25B 2nd port 25C 3rd port 25D 4th port 25E 5th port 27 Enlarged part 27A 1st enlarged part 27B 2 of the enlarged portion 27C third enlarged portion 27D fourth enlarged portions 30 vacuum tank 32,32-1,32-2,32-1A, 32-1B, 32-2A, 32-2B passage intersection

Claims (5)

Consists of at least a four-layer structure of a facing substrate, a first substrate, a thin film, and a second substrate,
The first substrate has at least one air passage on the facing substrate bonding surface side, and a first through hole and a second through hole disposed at both ends of the passage,
The thin film seals the opening of each through-hole of the first substrate, and the air passage and each through-hole are kept in a vacuum state, thereby being recessed into each through-hole. Forming a first recess and a second recess,
The second substrate has at least one fine channel on the thin film bonding surface side, and a port opened toward the atmosphere communicating with the fine channel is disposed at one end of the fine channel. The microfluidic chip is characterized in that the other end of the fine channel is disposed on the upper surface of the second recessed portion. 2. The microfluidic chip according to claim 1, wherein the facing substrate is made of glass, and the first substrate, the thin film, and the second substrate are all made of polydimethylsiloxane (PDMS). The microfluidic chip according to claim 1, wherein at least one microchannel is orthogonal to the at least one microchannel. A method of manufacturing a microfluidic chip, comprising:
(1) An air passage on one surface, a first substrate having a first through hole at one end of the air passage and a second through hole at the other end, the air passage forming surface side Bonding to the facing substrate;
(2) covering the first and second through holes of the first substrate by covering the upper surface of the first substrate with a thin film;
(3) The three-layer structure of the facing substrate, the first substrate and the thin film is placed in a vacuum chamber, and the air passage sealed in the first substrate and the air in each through hole are exhausted under reduced pressure. Forming a first recessed portion and a second recessed portion at positions corresponding to the first through hole and the second through hole, respectively.
(4) A second substrate having a fine channel on one surface and having a port opened toward the atmosphere at one end of the fine channel is connected to the fine channel. A method of manufacturing a microfluidic chip, comprising a step of bonding on the thin film so that the other end is disposed on an upper surface of the second recessed portion. 5. The method of manufacturing a microfluidic chip according to claim 4, wherein the facing substrate is made of glass, and the first substrate, the thin film, and the second substrate are all made of polydimethylsiloxane (PDMS).

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