JP2005199231A - Liquid sending apparatus and driving method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a highly integrated system for sending a very small amount of a liquid, which has a simple structure, in which electric power is seldom consumed and the liquid can be sent smoothly even when a flow passage is made minute. <P>SOLUTION: The liquid sending apparatus 11 is provided with a substrate 2 being a first substrate having a flow passage surface 3, a glass substrate 1 being a second substrate on which a working electrode 4 is formed at the position opposed to the flow passage surface 3 and a reference electrode 7. A predetermined distance is kept between the flow passage surface 3 and the working electrode 4. A fluid is placed between the substrate 2 and the glass substrate 1. The placed fluid is moved in a flow passage space 15 between the flow passage surface 3 and the working electrode 4 by producing a potential difference between the reference electrode 7 and the working electrode 4 in a state in which the reference electrode 7 is brought into contact with at least a part of the working electrode 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for controlling and feeding a small amount of fluid used in research fields such as chemistry, biology, medicine, material engineering, electrochemical engineering, semiconductor engineering, electronics, microchemical analysis, and nanotechnology, and the like The present invention relates to a driving method.

  In recent years, chemical reactions, cell culture, separation detection, etc. have been performed on a microchemical analysis system (μTAS) that performs chemical reactions on a chip, or a chip that has a small groove or indentation on a small substrate such as glass. Research on a lab-on-a-chip (lab on a chip) that integrates a lab process (lab process) is being actively conducted. As described above, this intends to miniaturize a conventional analysis system or chemical laboratory to the extent that it can be put on a palm.

  By miniaturizing the analysis system and the like, effects such as (1) a small amount of sample and reagent, (2) faster response, and (3) high throughput can be realized. The applications of these miniaturized analysis systems (hereinafter referred to as microsystems) are various, but on such microsystems, it is necessary to control and send a small amount of fluid. In particular, it is expected to realize a liquid delivery device in which all elements are integrated.

  Mechanical micropumps and microvalves have already been studied since the 1980s as devices for controlling and feeding a small amount of fluid. However, the construction of an advanced liquid delivery device in which these are integrated has been hardly successful so far. This seems to be due to the fact that it is difficult to achieve a high degree of structural integration. For this reason, when it is desired to introduce a minute fluid (for example, a solution) into a minute flow path and send it, a commercially available micro syringe pump is often used. Of course, this may be sufficient depending on the purpose such as basic research, but if a microsyringe pump is used, portability is impaired. Also, the micro syringe pump is very expensive.

  Therefore, as a means for feeding liquid in a relatively complicated microchannel, there is a liquid feeding mechanism that uses electroosmotic flow. The electroosmotic flow is a movement phenomenon that a solution in contact with a glass tube or the like exhibits under a high voltage, and is usually generated by analysis using capillary electrophoresis using DNA or the like as a measurement target. Capillary electrophoresis is performed by inserting an electrode into a solution reservoir containing DNA or other particles formed at the end of a microfluidic channel formed in quartz glass. This is a phenomenon in which a voltage is applied to move the solution in the microchannel. A liquid feeding mechanism using electroosmotic flow (hereinafter referred to as an electroosmotic pump) is structurally very simple and can be easily fed through a complicated flow channel network.

By the way, regarding the electroosmotic flow, for example, Patent Document 1 below discloses a material injection device of a capillary electrophoresis apparatus that suppresses electrophoresis and injects a material into a capillary by electroosmotic flow (Patent Document). 1).
Japanese Patent Laid-Open No. 5-142198 (first page, FIG. 1)

  However, conventional micropumps and microvalves have a problem that drive voltage and power consumption increase. Specifically, for example, even if the drive voltage is low, it is several tens of volts, and accordingly, power consumption has become a problem. Furthermore, the smaller the channel is, the greater the influence of interfacial tension and the like, and the resistance of the fluid flowing in the channel increases. For this reason, there is a problem that liquid feeding becomes difficult particularly when a conventional mechanical pump such as a micropump or a microvalve is used. Similarly, the electroosmotic pump also has a problem because a high voltage is required, and the power consumption becomes too large to be ignored.

  The present invention solves the above-mentioned problems, and has a highly integrated micro liquid feeding system that has a simple structure, consumes almost no power, and can perform smooth liquid feeding even if the flow path is miniaturized. It is an object to realize the system.

  In order to solve the above-mentioned problems, the present invention comprises a first substrate having a flow path surface, a second substrate having a working electrode formed at a position facing the flow path surface, and a reference electrode, A liquid delivery device disposed at a predetermined distance between a flow path surface and the working electrode, wherein a fluid is disposed between the first substrate and the second substrate; and In the state where the fluid is in contact with the reference electrode and at least a part of the working electrode, a potential difference is generated between the reference electrode and the working electrode, so that the fluid flows between the flow path surface and the working electrode. The liquid feeding device is characterized in that it moves in the channel space between the two.

  The present invention also includes a first substrate on which a channel portion having a channel surface is formed, a second substrate on which a working electrode is formed at a position facing the channel surface, and a reference electrode. A liquid delivery device disposed at a predetermined distance between the flow path surface and the working electrode, wherein a fluid is disposed between the first substrate and the second substrate; and In the state where the fluid is in contact with the reference electrode and at least a part of the working electrode, a potential difference is generated between the reference electrode and the working electrode, so that the fluid flows between the flow path surface and the working electrode. Provided is a liquid feeding device that moves in a flow path space between electrodes.

  The present invention also includes a first substrate on which a channel portion having a channel surface is formed, a reference electrode, and a second substrate on which a working electrode is formed at a position facing the channel surface. The liquid delivery device is disposed with a predetermined distance between the flow path surface and the working electrode, and a fluid is disposed between the first substrate and the second substrate, And in the state which made this fluid contact the said reference electrode and at least one part of the said working electrode, an electric potential difference is produced between the said reference electrode and the said working electrode, The said fluid and the said flow-path surface Provided is a liquid feeding device which moves in a flow path space between the working electrode.

  The present invention also provides a first substrate on which a flow path portion having a flow path surface is formed, a reference electrode, a counter electrode, and a second electrode on which a working electrode is formed at a position facing the flow path surface. , And is a liquid feeding device that is disposed with a predetermined distance between the flow path surface and the working electrode, and fluid is passed between the first substrate and the second substrate. Placing the fluid in contact with the reference electrode, the counter electrode, and at least a part of the working electrode, thereby creating a potential difference between the reference electrode and the working electrode, Provided is a liquid feeding device, wherein a fluid moves in a flow path space between the flow path surface and the working electrode.

  It is preferable that a liquid reservoir for storing the fluid is formed on the first substrate.

  The reference electrode is preferably formed of an electrode substrate made of silver and a film layer made of silver chloride formed on the electrode substrate.

  The working electrode is preferably made of gold, carbon, or bismuth.

  The working electrode is preferably composed of a plurality of working electrode elements, and a predetermined gap is provided between the working electrode elements.

  On the second substrate, it is preferable that a hydrophobic film layer is formed at least in a peripheral portion at a position facing the flow path surface.

  The first substrate is preferably made of a hydrophobic resin material.

  It is preferable that the potential of the working electrode is set within a range of potential that causes a change in interfacial tension due to adsorption of cations in the fluid.

  The second substrate is preferably provided with a mixing electrode for mixing a fluid that moves in a flow path space between the flow path surface and the working electrode.

  Preferably, the second substrate is provided with a sensor that detects a fluid that moves in a channel space between the channel surface and the working electrode or a fluid mixed by the mixed electrode.

  The present invention also includes a first substrate on which a channel portion having a channel surface is formed, a second substrate on which a working electrode is formed at a position facing the channel surface, and a reference electrode. Preparing a liquid feeding device arranged at a predetermined distance between the flow path surface and the working electrode, and arranging a fluid between the first substrate and the second substrate; And in the state which made this fluid contact the said reference electrode and at least one part of the said working electrode, by making a potential difference between the said reference electrode and the said working electrode, the said fluid is made into the said flow-path surface A liquid-feeding device for moving a flow path space between the working electrode and the working electrode, wherein the potential of the working electrode is within a potential range in which a change in interfacial tension is caused by adsorption of cations in the fluid. The method for driving the liquid delivery device is provided.

  Further, the present invention provides a first substrate in which a channel portion having a channel surface is formed, and a second substrate in which a working electrode composed of one or a plurality of working electrode elements is formed at a position facing the channel surface. And a reference electrode, and a liquid delivery device is provided that is disposed at a predetermined distance between the flow path surface and the working electrode, and a fluid is supplied to the first substrate and the reference electrode. A potential difference is generated between the reference electrode and the working electrode in a state of being disposed between the second substrate and the fluid being in contact with the reference electrode and at least a part of the working electrode. The liquid feeding device driving method for moving the fluid in the flow path space between the flow path surface and the working electrode, and is applied only to the working electrode element in which the meniscus of the fluid exists. Provided is a method for driving a liquid delivery device characterized by applying a voltage. .

  According to the liquid feeding device and the liquid feeding device driving method according to the present invention having the above-described configuration, it has a simple structure, consumes little power, and performs smooth liquid feeding even if the flow path is miniaturized. Highly integrated micro liquid feeding system capable of

(principle)
One effective means for solving the problems of the present invention is to simplify as much as possible the structure and function of liquid feeding used in conventional micropumps and microvalves. In addition, if an electrochemical principle is used like the above-mentioned electroosmotic flow pump, it is advantageous as a solution method of the problem of simplifying the structure and function of these liquid feeding.

  Interfacial tension can be considered as one of the sources of resistance of the fluid flowing through the miniaturized flow path. However, the inventors of the present invention conceived that if this interfacial tension is used as a driving force for liquid feeding, a very efficient liquid feeding mechanism can be realized. By the way, the interfacial tension between the electrode and the fluid (particularly electrolyte) interface can be controlled by the electrode potential (this control method is called electrowetting).

  Further, the principle of liquid feeding based on the above electrowetting will be described. FIG. 1 is a schematic diagram showing the principle of liquid feeding. FIG. 1 is a side sectional view showing a state in which the droplet 31 is placed on the substrate 34. The droplet 31 is, for example, an electrolytic solution. The substrate 34 is formed by providing a film layer 34b made of, for example, a polymer on a metal substrate 34a made of, for example, gold.

  In the case of FIG. 1, the substrate 34 on which the droplet 31 is placed and in contact is called a working electrode (working electrode, driving electrode), and the other electrode in contact with the droplet 31 is a reference electrode ( Reference electrode, reference electrode) 33. In a state where the droplet 31 is placed on the substrate 34 and the droplet 31 is in contact with the reference electrode 33, a voltage is applied to the substrate 34, that is, the working electrode, so that the working electrode and the reference electrode 33 are interposed. Create a potential difference. FIG. 1A shows a state before the voltage is applied, and FIG. 1B shows a state where the voltage is applied.

  As shown in FIGS. 1A and 1B, the droplet 31 in a state in which a voltage is applied is more than the contact angle θ (see FIG. 1A) of the droplet 31 with respect to the substrate 34 before the voltage is applied. The contact angle θ ′ with respect to the substrate 34 (see FIG. 1B) becomes smaller. That is, when a voltage is applied, the substrate (working electrode) 34 is easily wetted.

  This is considered to be due to the following principle. As shown in FIG. 1B, the arrow 33a is the interfacial tension generated between the gas and the solid, the arrow 33b is the interfacial tension generated between the gas and the liquid, and the arrow 33c is between the solid and the liquid. It is the interfacial tension that occurs. When the potential of the substrate (working electrode) 34 is changed, the interfacial tension (arrow 33c) between the solid substrate 34 and the liquid droplet 31 (at the interface between the substrate 34 and the droplet 31) decreases. In other words, the substrate 34 is easily wetted by the droplets 31. Then, due to the interfacial tension between the gas and the solid (arrow 33a), the droplet 34 travels on the substrate 34 and is fed. When the voltage application is stopped and the potential is returned to the original state, liquid feeding stops.

  Note that the interfacial tension (arrow 33c) between the substrate 34 and the droplet 31 (at the interface between the substrate 34 and the droplet 31) affects the adsorption of ions in the droplet 31 to the surface of the substrate 34. It is. When it is changed to a more negative potential, adsorption of the cation becomes dominant, and when it is changed to a more positive potential, adsorption of the anion becomes dominant.

  In principle, this electrowetting method consumes little power. Based on this electrowetting principle, the present inventors have invented a new liquid delivery device (mechanism) that can deliver liquid smoothly.

In the liquid feeding device of the present invention for feeding liquid by electrowetting, the following devices are devised.
(1) An electrode that generates a driving force for liquid feeding, that is, a working electrode (working electrode, driving electrode) is formed to be elongated along the flow path portion of the fluid to be fed. By forming in this way, the structure of the liquid delivery device (drive circuit) can be simplified as compared with the drive circuit of the prior art. That is, in the conventional driving circuit, each working electrode formed in, for example, a quadrilateral shape is arranged in order, and the droplet is moved by sequentially switching the potential of each working electrode. For this reason, the conventional drive circuit has a complicated configuration. The structure of the liquid delivery device (drive circuit) of the present invention is greatly different from the structure of such a conventional complicated drive circuit, and has the advantage that it can be simplified.
(2) Conventionally, when a minute (trace amount) fluid is sent, droplets are usually moved instead of a continuous fluid. In order to move the droplet, two meniscuses (curved surfaces formed by the surface of the droplet placed in a tube or the like) at the front and rear in the traveling direction of the droplet are used. On the other hand, in the liquid feeding device of the present invention, the liquid droplet (fluid to be fed) is sufficiently stored near the inlet of the liquid droplet (fluid to be fed), and behind the liquid droplet (fluid to be fed). Therefore, only the meniscus in front of the droplet (fluid to be fed) is used.
(3) In the liquid feeding device according to each embodiment of the present invention to be described later, a convex channel portion is formed on the substrate, and the upper surface of the channel portion is defined as a channel surface. And it is set as the structure which moves the fluid which should be sent along this flow-path surface.

  The best mode for carrying out the liquid delivery device according to the present invention will be described with reference to the drawings based on the embodiments.

  FIG. 2 is an exploded perspective view of the liquid delivery device 11 according to the first embodiment of the present invention. 3 (a) and 3 (b) are side cross-sectional views of the liquid delivery device 11 cut along XX 'in FIG. 2, and FIG. 3 (c) shows the liquid delivery device 11 in FIG. It is typical sectional drawing which shows the flow-path part 13 vicinity when cut | disconnecting by YY '. FIG. 3 shows a state in which the fluid 14 to be fed is arranged in the liquid feeding device 11.

  The liquid delivery device 11 includes a glass substrate 1 that is a second substrate on which electrodes are formed, and a substrate 2 that is a first substrate on which flow paths 13 are formed. In addition to the working electrode 4, the counter electrode 5, and the reference electrode 7, a contact pad 6 that is an electrical contact terminal is formed as an electrode on the glass substrate 1.

  In the substrate 2, the channel portion 13 is formed in a convex shape and has a channel surface 3. Specifically, the upper surface of the channel portion 13 formed in a convex shape is the channel surface 3 (3a, 3b, 3c). In the present embodiment, the flow path portion 13 is formed in a Y shape, and therefore the flow path surface 3 is also formed in a Y shape. That is, the channel surface 3 is formed in a Y-shape in which one elongated channel surface 3a branches into a bifurcated elongated channel surface 3b, 3c from the middle.

  In the conventional concept of the channel, a configuration in which a concave channel portion is formed on a substrate and the bottom surface of the channel portion formed in the concave shape is used as a channel surface is usually used. The example is completely different from the conventional concept, and conversely, a convex flow path portion 13 is formed on the substrate 2, and the upper surface of the convex flow path portion 13 becomes the flow path surface 3.

  In addition, a concave liquid reservoir (reservoir) 10 is formed on the substrate 2. The liquid reservoir 10 is formed adjacent to the end 3d of the flow path 13 having the flow path surface 3a. The liquid reservoir 10 is for storing a fluid (solution, droplet, sample) 14 to be sent along the flow path surface 3. Since the liquid reservoir 10 is formed adjacent to the end portion 3d of the flow path portion 13, the end portion 3d of the flow path portion 13 is stored in a state where the fluid 14 to be fed is stored in the liquid reservoir portion 10. Is in contact with the fluid 14 stored in the liquid reservoir 10. The liquid reservoir 10 is formed with an inlet 8 (not shown in FIG. 2; see FIGS. 3A and 3B) for introducing the fluid 14.

  The substrate 2 is made of a hydrophobic resin material, and materials such as silicone rubber, acrylic, and PET (polyethylene terephthalate) are conceivable. In this embodiment, the substrate 2 is formed of PDMS (polydimethylsiloxane) (the substrate 2 is also referred to as a PDMS substrate). By forming the substrate 2 with such a resin material, in addition to the property of hydrophobicity, there is an advantage that the processing is simple.

  The surface 2a of the substrate 2 on which the flow path portion 13 and the liquid reservoir portion 10 are formed is turned over as indicated by an arrow g, and is opposed to the surface 1a of the glass substrate 1 on which the electrodes are formed. Thus, the liquid feeding device 11 is assembled and completed.

  On the other hand, the working electrode 4, the counter electrode 5, and the reference electrode 7 are formed on the glass substrate 1, and a three-electrode system (three-electrode system) is adopted. The three-electrode method is a method of measuring a current flowing between the working electrode 4 and the counter electrode 5 while applying a potential difference between the working electrode 4 and the reference electrode 7. The working electrode 4 is an electrode for applying a voltage, and is an electrode for generating a driving force for liquid feeding. The reference electrode 7 is an electrode serving as a potential reference. By adopting the three-electrode method, the current does not flow through the reference electrode 7 so that the potential of the reference electrode 7 serving as a potential reference is not shifted due to the influence of the current or the like. A potential difference can be accurately applied to the reference electrode 7.

  In the present embodiment, the three-electrode system is adopted, but the counter electrode 5 is not provided (the counter electrode 5 and the reference electrode 7 are integrated), and the working electrode 4 and the reference electrode 7 only (two-electrode system). May be adopted.

  The working electrode 4 and the counter electrode 5 are made of gold, for example. The working electrode 4 and the counter electrode 5 may be made of carbon or bismuth in addition to gold. In particular, the working electrode 4 is preferably formed of gold, carbon, or bismuth. This is because when a voltage is applied to the working electrode 4, hydrogen or the like is not generated and is not easily deteriorated. The reference electrode 7 is formed of an electrode substrate made of silver, a film layer made of silver chloride formed on the electrode substrate, and (hereinafter referred to as silver / silver chloride or Ag / AgCl). Thus, the reference electrode 7 is preferably formed of silver / silver chloride. By forming the reference electrode 7 with silver / silver chloride, there is an advantage that the potential of the reference electrode 7 does not change much even when a current is passed.

  The reference electrode 7 can be formed by immersing a silver electrode substrate (chip) in a 1 M (mol / liter) KCl solution and passing a constant current between it and an appropriate counter electrode (for example, a platinum plate). good. Thereby, the reference electrode 7 formed of silver / silver chloride is completed.

  The working electrode 4 is formed on the glass substrate 1 at a position facing the flow path surface 3 of the substrate 2. That is, on the glass substrate 1, the working electrode 4 is formed in a substantially Y shape along the flow path surface 3 at a position facing the Y-shaped flow path surface 3 formed on the substrate 2. More specifically, the working electrode 4 is composed of a plurality of working electrode elements 4a, 4b, 4c. A predetermined gap 9 is provided between each of the working electrode elements 4a, 4b, and 4c, and two elongated working electrodes that are arranged in a bifurcated manner with one elongated working electrode element 4a and each gap 9 interposed therebetween. The elements 4b and 4c are formed in a substantially Y shape. On the glass substrate 1, the gap 9 provided between the working electrode elements 4a, 4b, 4c is made hydrophilic.

  The working electrode 4 is composed of the working electrode elements 4a, 4b, 4c by applying (setting) a potential to each working electrode element 4a, 4b, 4c individually. This is because the fluid can be sent in any direction along 4c.

  Further, in the glass substrate 1, a hydrophobic film layer is formed at least in the peripheral portion at a position facing the flow path surface 3. In the present embodiment, in the glass substrate 1, except for the position 20 facing the liquid reservoir 10, the peripheral portion 18 surrounding the working electrode 4 (4 a, 4 b, 4 c) and the gap 9 (the hatched portion in FIG. 4C described later). Reference) is formed with a hydrophobic film layer. This is to effectively prevent the fluid 14 moving along the working electrode 4 on the glass substrate 1 from flowing outside the working electrode 14 and the gap 9.

  As shown in FIGS. 3A and 3B, the reference electrode 7 and the counter electrode 5 are formed at positions on the glass substrate 1 where the liquid reservoir portion 10 formed on the substrate 2 faces the glass substrate 1. Yes. Therefore, the reference electrode 7 and the counter electrode 5 are located in the vicinity of the introduction port 8 through which the fluid (solution, droplet, sample) 14 is introduced. As a result, when the fluid 14 introduced from the introduction port 8 is stored in the liquid reservoir 10, the fluid 14 comes into contact with the reference electrode 7 and the counter electrode 5.

  As described above, in this embodiment, the working electrode 4 is formed in a substantially Y shape, and has an irregular configuration in which the working electrode 4 is formed larger than the reference electrode 7 and the counter electrode 5. In this respect, the working electrode, the reference electrode, and the counter electrode are different from a conventional three-electrode system configuration in which the same size is formed.

  In this embodiment, the working electrode 4 is composed of a plurality of working electrode elements 4a, 4b, and 4c and is formed in a substantially Y shape. However, the working electrode 4 is not limited to a substantially Y shape, and a plurality of working electrode elements. Can be formed into various shapes.

  In this embodiment, two reference electrodes 7 and two counter electrodes 5 are formed (see FIG. 2), but one of each is a spare. Further, in this embodiment, the reference electrode 7 and the counter electrode 5 are formed on the glass substrate 1. However, if the fluid 14 to be fed stored in the liquid reservoir 10 can contact the reference electrode 7 and the counter electrode 5, However, it may not necessarily be formed on the glass substrate 1. For example, it may be formed on the substrate 2 or outside the glass substrate 1 and the substrate 2.

  In the liquid delivery device 11 according to the present embodiment of the present invention, the substrate 2 on which the working electrode 4 and the like having the above-described configuration are formed and the substrate 2 on which the flow path portion 13 and the like are formed are separately manufactured. Is done. As described above, the surface 1a of the glass substrate 1 on which the working electrode 4 and the like are formed and the surface 2a of the substrate 2 on which the flow path portion 13 and the like are opposed are assembled and completed. At this time, in the liquid delivery apparatus 11, as shown in FIG. 3, the flow path surface 3 and the working electrode 4 are arranged with a predetermined interval h.

  In order to maintain a predetermined distance h between the flow path surface 3 and the working electrode 4, for example, a spacer 16 is inserted between the substrate 2 and the glass substrate 1 as shown in FIG. The liquid feeding device 11 is assembled. The spacer 16 is made of a resin material such as silicone rubber. The predetermined interval h can be adjusted by the spacer 16. In the present embodiment, the predetermined interval h is, for example, 0.05 mm.

  In this way, a flow path space 15 having a predetermined interval h is formed between the flow path surface 3 and the working electrode 4. Then, the fluid 14 stored in the liquid reservoir 10 moves along the flow path surface 3 and the working electrode 4 using the flow path space 15 as a flow path and is fed. The predetermined distance h between the flow path surface 3 and the working electrode 4 is the height of the flow path (flow path height, flow path interval) through which the fluid 14 moves and is sent.

  In this embodiment, the spacer 16 is inserted in order to maintain a predetermined distance h. Instead of inserting the spacer 16, a predetermined distance is provided between the flow path surface 3 and the working electrode 4 on the glass substrate 1. The substrate 2 may be processed so as to have a shape that maintains the distance h.

(Function)
Next, the operation (driving method) of the liquid delivery device 11 according to the present embodiment will be described. In the liquid feeding device 11, a fluid 14 to be fed is introduced from an introduction port 8 provided in the substrate 2. In this embodiment, for example, a KCl solution is used as the fluid 14. The introduced fluid 14 is disposed between the substrate 2 and the glass substrate 1, specifically, between the liquid reservoir 10 formed on the substrate 2 and the glass substrate 1. At this time, the fluid 14 retained in the liquid reservoir 10 is in contact with at least a part of the counter electrode 5, the reference electrode 7, and the working electrode 4 on the glass substrate 1, for example, the end 4 d of the working electrode 4. And is in contact with the end 3d of the flow path surface 3 on the substrate 2 (see FIG. 3A).

  In this state, a potential difference is generated between the reference electrode 7 and the working electrode 4 by applying a voltage to the working electrode 4. The potential of the working electrode 4 is set within a range of potentials at which changes in the interfacial tension are caused by adsorption of ions in the fluid 14, more preferably by adsorption of cations. The range of the potential that causes the change in the interfacial tension varies depending on the predetermined interval h of the liquid delivery device 11, the material of the glass substrate 1 and the substrate 2, the degree of hydrophobicity, the surface state of the flow path surface 3 and the working electrode 4.

  The potential of the working electrode 4 is changed to, for example, an appropriate negative value within the range of potential at which the change in interfacial tension is caused. Then, the fluid 14 moves (advances) in the flow path space 15 along the flow path surface 3 and the working electrode 4 (more specifically, the working electrode 4a). In this way, the fluid 14 is fed (see FIG. 3B).

  The cross-sectional view of the liquid delivery device 11 in FIG. 3C shows a state in which the fluid 14 is fed into the flow path space 15 sandwiched between the flow path surface 3 and the working electrode 4. The fluid 14 stored in the liquid reservoir 10 is visible in the back of the flow path space 15 occupied by the fluid 14 being fed (back as viewed from the front of the paper).

  When the application of voltage to the working electrode 4 is stopped, that is, when the potential of the working electrode 4 is restored, the liquid feeding stops.

  As described above, the fluid 14 is fed as described above when the voltage is applied to the working electrode 4 and the interfacial tension between the working electrode 4 and the fluid 14 (working electrode 4-fluid 14 interface). This is because the fluid 14 is easily wetted on the working electrode 4.

  It is the adsorption of ions on the electrode surface that affects the interfacial tension between the fluid 14 and the electrode including the working electrode 4 (fluid 14-electrode interface). When the working electrode 4 is changed to a more negative potential, adsorption of cations on the electrode surface is dominant, and when the working electrode 4 is changed to a more positive potential, adsorption of anions on the electrode surface is dominant. Become.

  In the former case, that is, when the working electrode 4 is changed to a more negative potential and the cation is adsorbed on the electrode surface, the interface tension at the interface between the working electrode 4 and the fluid 14 is not greatly affected by the type of ions. . The electrodes including the reference electrode 7 and the like are not affected (does not depend on the type of ions).

  On the other hand, in the latter case, that is, when the working electrode 4 is changed to a more positive potential and an anion is adsorbed on the electrode surface, the interfacial tension at the interface between the working electrode 4 and the fluid 14 is greatly affected by the type of ions. coming out. Therefore, it is preferable to apply a negative voltage (potential) to the working electrode 4 in order to perform liquid feeding with high reproducibility.

  A further operation (driving method) will be described using the liquid delivery device 11 according to the embodiment of the present invention. In the liquid feeding device 11, the fluid 14 that feeds the flow path space 15 sandwiched between the flow path surface 3 and the reference electrode 4 along the working electrode 4 is driven and controlled as follows. FIG. 5 is an enlarged view of a part of the working electrode 4 showing how the fluid 14 is fed in the liquid feeding device 11.

  The working electrode 4 is composed of working electrode elements 4a, 4b and 4c. In the driving method of the present invention, a voltage (potential) is applied only to the working electrode elements 4a, 4b, and 4c where the meniscus 14a of the fluid 14 is present. Specifically, as already described above, when a potential is applied to the working electrode 4, more specifically, the working electrode element 4a, the liquid reservoir 10 (see FIGS. 2 and 3) extends along the working electrode element 4a. Thus, the fluid 14 moves (see FIG. 5A). The position up to which the fluid 14 has moved is shown by a dotted line in FIG. And the meniscus 14a of the fluid 14 exists in the front-end | tip part of the fluid 14 shown with a dotted line.

  Thereafter, the movement of the fluid 14 stops in the vicinity of the end portion 4a 'of the working electrode element 4a. At this time, since the gap 9 is hydrophilic, the fluid 14 oozes out into the gap 9, and the fluid 14 flows into the end portions 4 b ′ and 4 c ′ of the working electrode elements 4 b and 4 c that are arranged in a bifurcated manner through the gap 9. The meniscus 14a of the fluid 14 comes into contact and stops (the meniscus 14a of the fluid 14 is applied to the end portions 4b ′ and 4c ′) (see FIG. 5B).

  Next, no voltage (potential) is applied to the working electrode element 4b, and a voltage (potential) of −0.9 V, for example, is applied only to the working electrode element 4c. Then, the meniscus 14a of the fluid 14 moves in the direction of the working electrode element 4c, and the fluid 14 travels along the working electrode element 4c (see FIG. 5C)).

  Similarly, if a voltage (potential) is also applied to the working electrode element 4b, the meniscus 14a of the fluid 14 can be moved in the direction of the working electrode element 4b, and the fluid 14 is moved along the working electrode element 4c. Can advance. That is, it is possible to send the fluid 14 in any direction along each working electrode element 4a, 4b, 4c by individually setting the potential to each working electrode 4a, 4b, 4c. As described above, by applying a voltage (potential) only to the working electrode elements 4a, 4b, and 4c where the meniscus 14a of the fluid 14 is present, drive control can be performed also in the liquid feeding direction of the fluid 14. it can.

  A flow path space 15 between the working electrode 4 formed on the glass substrate 1 and the flow path surface 3 of the flow path portion 13 formed in a convex shape on the substrate 2 is provided along the flow path surface 3 and the working electrode 4. As a result, the fluid 14 moves. Such a configuration of the liquid delivery device 11 has the following effects.

  The flow path space 15 is only sandwiched between the flow path surface 3 and the working electrode 4 in the vertical direction, and the side is open, that is, the side is an air layer. When the fluid 14 moves in such a channel space 15, the fluid 14 forms a side wall (boundary) on the surface of the fluid 14 itself by surface tension, and the channel surface 3 and the working electrode 4 in the vertical direction Along the flow path space 15. Therefore, in the liquid feeding device 11 having such a configuration, resistance (liquid feeding resistance) on the side of the fluid 14 accompanying liquid feeding does not occur, that is, the liquid feeding resistance on the side can be eliminated.

  Liquid supply control (drive control) of the fluid 4 can be performed only in the vertical direction of the flow path space 15, that is, only by the flow path surface 3 and the working electrode 4.

  The fluid 14 disposed in the flow path space 15 during liquid feeding includes a working electrode 4 and a gap 9 in which a peripheral portion 18 (see FIG. 4C) of the glass substrate 1 is formed of a hydrophobic film, It will be in the state pinched | interposed with the flow-path surface 3 which the flow-shaped flow-path part 13 has. For this reason, the fluid 14 can be kept in a state of being confined in the flow path formed by the flow path surface 3, the working electrode 4 (and the gap 9), and the flow path space 15 on the working electrode 4. It does not spread to the side other than the flow path.

  Next, the manufacturing method of the liquid delivery apparatus 11 which concerns on the Example of this invention is demonstrated. Hereinafter, a manufacturing method of the liquid feeding device 11 for one chip will be described. However, it should be understood that a large number of the liquid feeding devices 11 are actually manufactured on a single substrate.

First, an electrode such as the working electrode 4 is formed on the glass substrate 1 of the present embodiment. FIG. 4 is a schematic diagram illustrating a process of forming the glass substrate 1. First, the glass substrate is washed in, for example, a mixed solution of NH ₄ OH, H ₂ O ₂ and pure water, rinsed (rinsed) in heated pure water, and then taken out and dried. The cleaned glass substrate is mounted on a sputtering apparatus, and a metal thin film layer is formed in the order of a chromium layer and a gold layer.

  For example, a positive photoresist is spin-coated (coated) on the glass substrate on which the metal thin film layer is formed. Thereafter, pre-baking is performed (baking to cure the photoresist).

  A photomask is passed through a glass substrate on which the photoresist is cured, and exposure is performed by irradiating ultraviolet rays with a mask aligner. Thereafter, the photoresist at the portion irradiated with ultraviolet rays is removed by development, whereby a resist pattern coated with the photoresist is formed. The glass substrate on which the resist pattern is formed is post-baked (baked).

  Dry etching of the chromium layer and the gold layer of the glass substrate is performed with a sputtering apparatus, and these metal layers (chromium layer, gold layer) in portions not covered with the photoresist are removed. Thereby, the pattern (gold pattern) of the electrode (metal electrode) used as a base is formed on a glass substrate (refer Fig.4 (a)).

  The glass substrate on which the electrode pattern is formed is immersed in acetone, and the photoresist is peeled off. A positive photoresist is spin-coated on the glass substrate from which the photoresist has been peeled off, and then prebaked.

  A photomask is passed through a glass substrate on which the photoresist has been cured, and similarly, exposure is performed with a mask aligner. The exposed glass substrate is immersed in toluene and immediately taken out and dried with nitrogen gas. Thereafter, post-baking is performed. The post-baked glass substrate is developed in a dedicated developer.

  Thereafter, a silver layer is formed (deposited) on the glass substrate by a sputtering apparatus. About the glass substrate in which the silver layer was formed, the photoresist layer was peeled in acetone and it wash | cleaned in clean acetone. Thereby, a silver pattern is formed only in the location which forms the reference electrode 7 on a glass substrate (refer FIG.4 (b)).

  A negative photoresist is spin-coated on a glass substrate on which a gold pattern and a silver pattern are formed, and then prebaked.

  By passing a photomask through a glass substrate coated with a negative photoresist and irradiating with ultraviolet rays, the peripheral portion of the position facing the flow path surface 3, for example, other than the position 20 facing the liquid reservoir 10, and The periphery of the working electrode 4 (4a, 4b, 4c) and the gap 9 is exposed to ultraviolet rays. Photoresist remains where the ultraviolet rays are irradiated.

  After that, as a result of developing and rinsing the glass substrate using a dedicated developer and a rinsing solution, the working electrode 4 (4a, 4b, 4c) and the gap 9 are located at positions other than the position 20 facing the liquid reservoir 10. A negative photoresist layer 18 that is a hydrophobic film is formed on the periphery of the substrate (see FIG. 4C).

  The glass substrate on which the negative photoresist layer 18 is formed is spin-coated on the entire surface of the glass substrate using a positive photoresist as a protective film and baked. Thereafter, the glass substrate is cut into chips by a dicing saw. Thereafter, it is washed with ethanol, and the dirt on the chip is thoroughly washed out and dried naturally. Thus, the glass substrate 1 of this example is completed.

  Next, a process for forming the flow path portion 13 and the flow path surface 3 on the substrate 2 of the present embodiment will be described. A thick film photoresist is spin-coated (coated) on the substrate and then pre-baked. Ultraviolet rays are irradiated through a photomask on the photoresist of the formed substrate. Thereby, an ultraviolet-ray is irradiated to the part in which the flow-path surface 3 is formed.

  The exposed thick film photoresist is developed with a dedicated developer and a rinse solution, and rinsed. In this way, the resist is removed from the portion where the flow path surface 3 is formed, whereby a mold is manufactured.

  The PDMS precursor solution is poured onto the mold that has been made. When the PDMS is cured, the PDMS is separated from the mold. Thereby, the board | substrate (PDMS board | substrate, PDMS structure) 2 in which the flow-path part 13 and the flow-path surface 3 were formed is completed.

  Next, the surface 1a on which the electrode of the completed glass substrate 1 is formed and the surface 2a on which the flow path surface 3 of the substrate 2 is formed are assembled so as to face each other (facing each other). At this time, the spacer 16 is placed and adjusted so that the working electrode 4 and the flow path surface 3 have a predetermined distance h. As described above, the liquid feeding device 11 is assembled and completed.

  FIG. 6 is a graph showing the potential dependence of the liquid feeding speed when the fluid 14 is fed using the liquid feeding apparatus 11 according to the first embodiment of the present invention. The horizontal axis represents the potential (referred to as E (V) vs. Ag / AgCl in the graph) with respect to the reference electrode 7 made of silver / silver chloride (Ag / AgCl), and the vertical axis represents the speed of liquid feeding. The moving distance (μm) of the fluid 14 per second is shown. As the fluid 14, a 1 mol / liter (1M) KCl solution is used. As shown in FIG. 6, an identifiable change in the movement of the fluid 14 was observed at a potential of −0.7 V or less.

  FIG. 7 shows the dependency of the liquid feeding speed of the fluid 14 on the height of the flow path. The horizontal axis indicates the height of the flow path (flow path height, flow path interval, predetermined interval h) (μm), and the vertical axis indicates the liquid 14 feeding speed (μm / second). The liquid feeding speed increases as the predetermined distance h between the flow path of the liquid feeding apparatus 11 according to the first embodiment of the present invention, that is, the flow path surface 3 of the substrate 2 and the working electrode 4 of the glass substrate 1 is narrowed. I understand that In other words, the liquid delivery device 11 becomes more advantageous as the miniaturization proceeds.

  In addition, FIG. 8 shows the time passage of the fluid 14 and the dependence of current and power consumption. The horizontal axis indicates the time (seconds, s) for feeding the fluid 14, the vertical axis on the right side of the paper indicates the current value (μA), and the vertical axis on the left side of the paper indicates the power consumption (μW). In the graph of FIG. 8, current values are indicated by lines C1 and C2, and power consumption values are indicated by lines P1 and P2. As shown in FIG. 8, in the liquid delivery device 11 according to the first embodiment of the present invention, the contact area between the working electrode 4 composed of the working electrode elements 4a, 4b, and 4c and the fluid 14 is the movement of the fluid 14. As it increases with time, the current value gradually increases while moving on one working electrode element (4a, 4b or 4c). The state in which the meniscus 14a of the fluid 14 is moved from one working electrode element to the next working electrode element and the working electrode element to which the voltage is applied is switched from the C1 line (P1 line) to the C2 line. This corresponds to the state changed to (P2 line).

  Since the driving force of the fluid 14 is generated in the meniscus 14a portion of the fluid 14, the working electrode 4 serving as a flow path is composed of a plurality (pieces) of working electrode elements 4a, 4b, and 4c. For example, a potential (voltage) may be applied only to the working electrode element in which the meniscus 14a of the fluid 14 is present among the plurality of working electrode elements 4a, 4b, and 4c.

  Further, as shown in FIG. 8, the generated current value is about several tens of μA, and the power consumption value is about several tens of μW. These current values and power consumption values are very small compared to the case of using a conventional micropump or the like. The source of the current value is a Faraday current associated with the reduction of oxygen, etc., and by adjusting the height of the flow path (flow path height, flow path interval, predetermined interval h) to lower the drive potential, Low power consumption can be realized.

  The liquid feeding device 61 according to the second embodiment of the present invention is similar to the configuration of the liquid feeding device 11 according to the first embodiment, and illustration and description of the same components as those of the liquid feeding device 11 according to the first embodiment are omitted. FIG. 9A is a schematic partially enlarged view showing the vicinity of the flow path (specifically, part of the working electrode) of the liquid delivery device 61 according to the second embodiment of the present invention.

  One of the features of the liquid feeding device 61 according to the second embodiment which is different from the liquid feeding device 11 of the first embodiment is that between the working electrodes 50 and 51 constituting the flow path and the flow path surface (not shown in FIG. 9). The mixing electrode 52 for mixing the fluid moving through the flow path space is provided.

  In the liquid feeding device 61, working electrodes 50 and 51 each including a plurality of working electrode elements are formed on the glass substrate 1 (see FIGS. 2 and 3). Each working electrode 50, 51 is adjacent to a liquid reservoir 10 for storing fluid, and a reference electrode 7 and a counter electrode 5 (both see FIG. 2) are formed in the same manner as in the first embodiment. . In the liquid feeding device 61 of the present embodiment, the mechanism and drive for feeding fluid along the respective working electrodes 50 and 51 to the flow passage space 15 (flow passage) sandwiched between the flow passage surface and the working electrodes 50 and 51. The method is the same as that of the liquid delivery device 11 of the first embodiment.

  In FIG. 9A, one working electrode element 50a among the plurality of working electrode elements constituting the working electrode 50 and one working electrode element 51a among the plurality of working electrode elements constituting the working electrode 51 are shown. Are shown. Between the working electrode element 50a and the working electrode element 51a that extend in parallel, a rectangular mixed electrode 52 that is elongated in parallel along the respective working electrode elements 50a and 51a is formed.

  Similar to the working electrodes 50 and 51, the mixed electrode 52 has a role as a driving electrode that applies a voltage and sends a fluid, and is made of the same material as the working electrodes 50 and 51, for example. Such a mixed electrode 52 can be easily formed in the same manner as described in the first embodiment only by changing the pattern of the photomask used for the glass substrate 1 shown in FIG. 4 of the first embodiment. it can.

  In the liquid feeding device 61, a plurality of fluids are fed along the respective working electrodes 50, 51, and each fluid is fed onto the mixing electrode 52, thereby mixing these fluids on the mixing electrode 52. Let More specifically, the fluid fed on the working electrode 50 is fed onto the working electrode element 50a from the direction indicated by the arrow 50g. In addition, another type of fluid fed on the working electrode 51 is fed onto the working electrode element 51a from the direction indicated by the arrow 51g.

  A predetermined gap 59 is provided between the mixing electrode 52 and each working electrode element 50a, 51a. The predetermined gap 59 is, for example, about 10% of the height h of the flow path (the thickness of the fluid moving through the flow path). By providing such a predetermined gap 59, the fluid fed on the working electrode elements 50a and 51a oozes out from the peripheral portions 50a ′ and 51a ′ of the working electrode elements 50a and 51a, and the mixed electrode 52 It is possible to effectively mix the fluid over both the peripheral portions 52a. The predetermined gap 59 is made hydrophilic.

  In order to feed and mix the fluid on the mixing electrode 52, the respective reference electrodes 7 and the counter electrode 5 provided in the vicinity of the respective liquid reservoirs 10 are used for the working electrodes 50 and 51, respectively. it can. The reference electrode 7 and the counter electrode 5 are used to send a fluid along the working electrodes 50 and 51, but are switched to the mixed electrode 52 when the fluid is mixed on the mixed electrode 52. Used. Alternatively, a reference electrode and a counter electrode for the mixed electrode 52 may be separately formed in the vicinity of the mixed electrode 52. Alternatively, the working electrode elements 50 a and 51 a can be used as a counter electrode when a fluid is fed on the mixed electrode 52.

(Function)
Next, the operation of the second embodiment will be described. FIG. 10 is a schematic partial enlarged view of the vicinity of the mixing electrode 52 showing how the fluid is mixed in the liquid delivery device 61 according to the second embodiment. First, the liquid feeding device 61 is driven and controlled, and two different types of fluids 53 and 54 are fed to the vicinity of the mixed electrode 52 on the working electrode elements 50a and 51a, respectively (FIG. 10A).

  The fed fluids 53 and 54 are slightly exuded from the peripheral portions 50a 'and 51a' of the working electrode elements 50a and 51a, and are applied to both peripheral portions 52a of the mixed electrode 52 (FIG. 10B).

  When a potential (voltage) is applied to the mixed electrode 52 in this state, the fluids 53 and 54 that have exuded from the working electrode elements 50a and 51a spread and mix on the mixed electrode 52. FIG. 10C shows a mixed fluid (liquid) 55. The time required for mixing the fluids 53 and 54 varies depending on the width of the flow path, that is, the width w between the working electrode elements 50a and 51a in this embodiment. For example, when the width w between the working electrode elements 50a and 51a is about 0.5 mm and the three electrodes of the working electrode elements 50a and 51a and the mixed electrode 52 are formed in the width w, the fluid 53 and 54 The time required for mixing is about several seconds.

(Modification)
FIG. 9B is a schematic partial enlarged view showing the vicinity of the flow path of the liquid feeding device 71 according to a modification of the liquid feeding device 61 of the second embodiment. In FIG. 9B, in the liquid feeding device 71, one working electrode element 70a among the plurality of working electrode elements constituting the working electrode 70 and the plurality of working electrode elements constituting the working electrode 71 are shown. One working electrode element 71a is shown. As in the second embodiment, a mixing electrode 72 is formed between the elongated working electrode elements 70a and 71a formed in parallel with a predetermined gap 79 interposed therebetween.

  In the modification shown in FIG. 9, a plurality of concave portions 70b arranged regularly are formed in the peripheral portions 70a'71a 'of the working electrode elements 70a, 71a located on the mixed electrode 72 side. A plurality of convex portions 72b regularly arranged corresponding to the concave portions 70b formed in the peripheral portions 70a'71a 'of the working electrode elements 70a and 71a are formed on both peripheral portions 72a of the mixed electrode 72. Has been. In short, the concave portions 70b of the working electrode elements 70a and 71a and the convex portions 72b of the mixed electrode 72 are formed in a comb shape with a predetermined gap 79 therebetween.

  By using the liquid feeding device 71 having the working electrode elements 70a and 71a having such a shape and the mixing electrode 72, fluid can be mixed more smoothly.

  The liquid feeding device 91 according to the third embodiment of the present invention is similar to the configuration of the liquid feeding device 11 according to the first embodiment, and illustration and description of the same components as those of the liquid feeding device 11 according to the first embodiment are omitted. FIG. 11 is a schematic partial enlarged view showing the vicinity of the flow path (specifically, part of the working electrode) of the liquid delivery device 91 according to the third embodiment of the present invention.

  In the liquid delivery device 91, a working electrode composed of a plurality of working electrode elements is formed on the glass substrate 1 (see FIGS. 2 and 3). The working electrode is adjacent to a liquid reservoir 10 for storing a fluid, and a reference electrode 7 and a counter electrode 5 (both see FIG. 2) are formed in the same manner as in the first embodiment. In the liquid feeding device 91 of the present embodiment, the mechanism and the driving method for feeding fluid to the flow path space 15 sandwiched between the flow path surface 3 and the working electrode along the working electrode are the liquid feeding device of the first embodiment. 11 is the same.

  FIG. 11 shows one working electrode element 80a among a plurality of working electrode elements constituting the working electrode.

  One of the features of the liquid feeding device 91 according to the third embodiment that is different from the liquid feeding device 11 of the first embodiment is that between the working electrode element 80a constituting the flow path and the flow path surface (not shown in FIG. 11). The sensor 84 for detecting the fluid moving in the flow path space is provided in the vicinity of the working electrode element 80a. Specifically, in this embodiment, the sensor 84 includes a detection working electrode 81 and a detection reference electrode 82, and the detection working electrode 81 and the detection reference electrode 82 are formed on the working electrode element 80a. The concave portions 80b and 80c are disposed respectively (see FIGS. 11C and 11D).

  The sensor 84 is used to analyze a single fluid that has been fed or a product that is generated by mixing a plurality of fluids that have been fed. In the present embodiment, by providing the sensor 84 in the vicinity of the working electrode element 80a, it is possible to analyze (detect) a single fluid that has been fed.

  For example, an electrochemical sensor is suitable as the sensor 84 when measuring the concentration of fluid. As a further specific example, if it is desired to measure an ion concentration such as pH of a fluid, an ion electrode may be used as the sensor 84. That is, a pH electrode (sensing working electrode) is used as the working electrode 81 for detection. In the present embodiment, for example, an iridium oxide film is used for the detection working electrode 81.

  About formation of an iridium thin film, it can form similarly to formation of the silver pattern demonstrated with the manufacturing method of the liquid feeding apparatus 11 of Example 1. FIG. Then, an oxide film is formed on the iridium thin film pattern 61. The oxide film can be formed by immersing the electrode substrate (chip) in an aqueous lithium perchlorate solution and repeatedly sweeping the iridium thin film potential. In this way, the detection working electrode 81 of this embodiment is completed.

  For the detection working electrode 81, a detection reference electrode 82 serving as a potential reference is separately provided in the vicinity of the working electrode element 80a. (Refer FIG.11 (c)). The reference electrode for detection 82 can also be formed in the same manner as the formation of the silver pattern to be the reference electrode 7 described in the method for manufacturing the liquid delivery device 11 of Example 1.

  A hydrophobic insulating film layer 83 (shaded portion) is formed around the working electrode element 80a constituting the flow path, as in the first embodiment. The insulating film layer 83 can be formed by using, for example, a negative photoresist as in the first embodiment (see FIG. 11D).

  If the fluid to be fed always contains a certain amount of ions, the pH of the fluid can be measured by measuring the potential of the detection working electrode 81 with respect to the detection reference electrode 82. Use a voltmeter with high input resistance to measure the potential. Since the potential of the detection working electrode 81 changes linearly with respect to pH, the pH of the fluid can be known from the potential of the detection working electrode 81 if calibration is performed using an appropriate standard solution.

  In the present embodiment, the case where pH sensing is performed using the sensor 84 has been described. On the other hand, if a minute ion electrode is formed as the detection working electrode 81, for example, a sensor capable of measuring various ions can be obtained. Furthermore, by immobilizing an enzyme that generates detectable ions on the formed micro ion electrode, a biosensor is obtained. That is, it is possible to measure a biological substance subjected to the action of a fixed enzyme (an enzyme that generates detectable ions) by the sensor.

  In the present embodiment, the case where ions are measured by measuring the potential of the detection working electrode 81 has been described. On the other hand, a sensor of the type that senses by a change in current value using an electrode reaction can be formed in the same manner. In this case, a counter electrode is used in addition to the detection working electrode 81 and the detection reference electrode 82.

  In the case of sensing by changing the current value using an electrode reaction, the detection working electrode 81 and the detection reference electrode 82 can be formed of, for example, platinum and silver / silver chloride, respectively. The counter electrode may be separately formed in the vicinity of the working electrode element 80a, or may be separately formed apart from the working electrode element 80a. Alternatively, when the working electrode element 80a (see FIGS. 2 and 3) used to send the fluid when detecting the fluid is not used, the working electrode element 80a can be used as a counter electrode.

  When sensing based on a change in current value using an electrode reaction, a constant potential is applied to the detection reference electrode 82 to detect a current value generated along with the electrode reaction. An electrode active material that can be oxidized and reduced on the detection working electrode 81 can be measured by detecting this current value. In addition, if an enzyme capable of generating an electrode active material such as hydrogen peroxide is fixed on the detection working electrode 81, a biosensor for measuring a biological substance subjected to the action of the enzyme can be obtained.

  In this embodiment, the sensor 84 of the present invention is provided in the vicinity of the working electrode element 80a. However, it may be provided in the vicinity of the mixed electrodes 52 and 72 (see FIG. 9) as described in the second embodiment. In this case, the sensor 84 can analyze (detect) a product produced by mixing a plurality of types of fluids at the mixing electrodes 52 and 72.

  According to the present invention, by applying a potential to the working electrode, it is possible to easily control the movement of the fluid using the interfacial tension of the fluid and to smoothly feed the fluid. This eliminates the need for a check valve (check valve) to prevent the backflow of fluid, which was necessary when liquid was fed using a conventional mechanical micropump or microvalve, and was complicated in the past. In addition, the structure of the liquid delivery device can be simplified.

  In each of the above embodiments of the present invention, the working electrode formed on the glass substrate 1 serving as the second substrate and the flow channel surface included in the convex flow channel formed on the substrate 2 serving as the first substrate. The channel space sandwiched between the two is used as a channel through which fluid is fed. On the other hand, the flow path portion is not necessarily formed in a convex shape in the first substrate. For example, a plane on the first substrate may be used as the flow path surface. In this case, a liquid feeding device is configured by the first substrate having a planar flow path surface and the second substrate having the working electrode formed at a position facing the flow path surface. It is also conceivable that the liquid feeding device is constituted by a first substrate having a channel portion formed in a concave shape and having a bottom surface as a channel surface, and a second substrate on which a working electrode is formed.

  The best mode of the liquid delivery device according to the present invention has been described based on the embodiments. However, the present invention is not particularly limited to such embodiments, and the scope of the technical matters described in the claims. It goes without saying that there are various embodiments within.

  Examples of the use of the present invention include miniaturization and integration of laboratories for medical and basic research such as local injection of objects, microanalysis systems such as DNA and proteins, and cell culture / separation detection. Laboratory chips, sensors, microreactors and the like.

It is a schematic diagram which shows the principle of liquid feeding. It is a disassembled perspective view of the liquid feeding apparatus which concerns on Example 1 of this invention. FIGS. 3A and 3B are side cross-sectional views of the liquid feeding device according to the first embodiment cut along XX ′ in FIG. 2, and FIG. 3C is the liquid feeding device according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing the vicinity of a flow path portion when cut along a line YY ′ in FIG. 2. It is a typical figure which shows the formation process of the glass substrate of the liquid feeding apparatus which concerns on Example 1 of this invention. In the liquid feeding apparatus which concerns on Example 1 of this invention, it is the figure which expanded a part of working electrode which shows a mode that a fluid is sent. It is a graph which shows the electric potential dependence of the liquid feeding speed at the time of liquid feeding using the liquid feeding apparatus which concerns on Example 1 of this invention. It is a graph which shows the dependence with respect to the height of a flow path of the liquid feeding speed. It is a graph which shows the dependence of the passage of time of fluid feeding, current, and power consumption. FIG. 9A is a schematic partial enlarged view showing the vicinity of the flow path of the liquid feeding device according to the second embodiment of the present invention, and FIG. 9B is a modified example of the liquid feeding device of the second embodiment. It is a typical fragmentary enlarged view which shows the flow path vicinity of the liquid feeding apparatus which concerns on this. In the liquid delivery apparatus which concerns on Example 2, it is a typical fragmentary enlarged view of a mixing electrode vicinity which shows a mode that a fluid mixes. It is a typical partial enlarged view which shows the flow path vicinity of the liquid feeding apparatus which concerns on Example 3 of this invention.

Explanation of symbols

1 glass substrate 1a, 2a surface 2, 34 substrate 3, 3a, 3b, 3c flow path surface 3d, 4d, 4b ′, 4c ′ end 4, 50, 51 working electrode 4a, 4b, 4c, 50a, 51a, 70a, 71a, 80a Working electrode element 4a 'Terminal 5 Counter electrode 6 Contact pad 7, 33 Reference electrode 8 Inlet 9, 59, 79 Gap 10 Liquid reservoir (reservoir)
11, 61, 71, 91 Liquid feeding device 13 Channel portion 14, 53, 54 Fluid 14a Meniscus 15 Channel space 16 Spacer 31 Droplet 33a, 33b, 33c Arrow 52, 72 Mixed electrode 50g, 51g Arrow 50a ', 51a ', 70a', 71a 'Peripheral portions 70b, 80b, 80c Concave portions 72a Both peripheral portions 72b Convex portions 81 Detection working electrode 82 Detection reference electrode 83 Insulating film layer 84 Sensor

Claims (15)

A first substrate having a flow path surface;
A second substrate having a working electrode formed at a position facing the flow path surface;
A liquid-feeding device provided with a reference electrode, and being arranged with a predetermined distance between the flow path surface and the working electrode,
In a state where a fluid is disposed between the first substrate and the second substrate and the fluid is in contact with at least part of the reference electrode and the working electrode, A liquid feeding device, wherein the fluid moves in a channel space between the channel surface and the working electrode by generating a potential difference with the working electrode. A first substrate on which a channel portion having a channel surface is formed;
A second substrate having a working electrode formed at a position facing the flow path surface;
A liquid-feeding device provided with a reference electrode, and being arranged with a predetermined distance between the flow path surface and the working electrode,
In a state where a fluid is disposed between the first substrate and the second substrate and the fluid is in contact with at least part of the reference electrode and the working electrode, A liquid feeding device, wherein the fluid moves in a channel space between the channel surface and the working electrode by generating a potential difference with the working electrode. A first substrate on which a channel portion having a channel surface is formed;
A second substrate having a reference electrode and a working electrode formed at a position opposite to the flow path surface, and the flow path surface and the working electrode are arranged at a predetermined distance. A liquid delivery device comprising:
In a state where a fluid is disposed between the first substrate and the second substrate and the fluid is in contact with at least part of the reference electrode and the working electrode, A liquid feeding device, wherein the fluid moves in a channel space between the channel surface and the working electrode by generating a potential difference with the working electrode. A first substrate on which a channel portion having a channel surface is formed;
A second substrate having a reference electrode, a counter electrode, and a working electrode formed at a position facing the flow path surface, and maintaining a predetermined distance between the flow path surface and the working electrode. A liquid delivery device arranged,
The fluid is disposed between the first substrate and the second substrate, and the fluid is in contact with the reference electrode, the counter electrode, and at least a part of the working electrode. A liquid feeding apparatus, wherein the fluid moves in a flow path space between the flow path surface and the working electrode by generating a potential difference between the electrode and the working electrode.   5. The liquid feeding device according to claim 1, wherein a liquid reservoir for storing the fluid is formed on the first substrate. 6.   6. The liquid feeding device according to claim 1, wherein the reference electrode is formed of an electrode substrate made of silver and a film layer made of silver chloride formed on the electrode substrate. apparatus.   The liquid feeding device according to claim 1, wherein the working electrode is made of gold, carbon, or bismuth.   The liquid feeding device according to claim 1, wherein the working electrode includes a plurality of working electrode elements, and a predetermined gap is provided between the working electrode elements. .   The liquid feeding device according to claim 2, wherein a hydrophobic film layer is formed on at least a peripheral portion of the second substrate facing the flow path surface. .   The liquid feeding device according to claim 1, wherein the first substrate is made of a hydrophobic resin material.   11. The liquid feeding device according to claim 1, wherein the potential of the working electrode is set within a potential range in which a change in interfacial tension is caused by adsorption of cations in the fluid.   The mixing electrode for mixing the fluid which moves the flow path space between the flow path surface and the working electrode is provided on the second substrate. Liquid feeding apparatus of description.   The sensor for detecting a fluid that moves in a flow path space between the flow path surface and the working electrode or a fluid mixed by the mixed electrode is provided on the second substrate. To 12. The liquid delivery device according to any one of 12 to 12. A first substrate on which a channel portion having a channel surface is formed;
A second substrate on which a working electrode is formed and a reference electrode are provided at a position facing the flow channel surface, and the flow channel surface and the working electrode are arranged with a predetermined distance therebetween. Prepare the liquid delivery device,
A fluid is disposed between the first substrate and the second substrate, and the fluid is in contact with at least part of the reference electrode and the working electrode; A liquid-feeding device driving method for causing the fluid to move in a flow path space between the flow path surface and the working electrode by generating a potential difference with the working electrode,
A method for driving a liquid feeding device, wherein the potential of the working electrode is set within a potential range in which a change in interfacial tension is caused by adsorption of cations in the fluid. A first substrate on which a channel portion having a channel surface is formed;
A second substrate on which a working electrode composed of one or a plurality of working electrode elements is formed at a position facing the flow path surface; and a reference electrode; between the flow path surface and the working electrode Prepare a liquid delivery device arranged at a predetermined distance,
A fluid is disposed between the first substrate and the second substrate, and the fluid is in contact with at least part of the reference electrode and the working electrode; A liquid-feeding device driving method for causing the fluid to move in a flow path space between the flow path surface and the working electrode by generating a potential difference with the working electrode,
A method for driving a liquid feeding device, wherein a voltage is applied only to the working electrode element in which the meniscus of the fluid exists.

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