JP5944118B2 - Particle measuring device - Google Patents

Description

  The present invention relates to a particle measuring apparatus capable of measuring particles present in a sample, such as a blood cell measuring apparatus that measures blood cells in blood as a sample.

  Conventionally, measuring particles present in a sample is important in manufacturing process accuracy control (for example, inspection for contamination) in fields such as electronics and mechatronics. In the field of biotechnology, measurement of particles in a sample has been performed for a long time in pharmaceutical manufacturing and the like.

  Today, in the medical field, measuring and counting the number of red blood cells, white blood cells, and platelets (here called blood cells) in a sample (blood) is an important test for knowing the health condition of a subject. It is an item. Examples of methods for measuring blood cells in blood include a light scattering method and an electrical resistance method, but a blood cell counter using the electrical resistance method has been developed because of its simple device configuration (for example, Patent Document 1).

  Also, in recent years, due to the advantage that the amount of blood necessary for measurement is very small, the blood cell counter using the electrical resistance method is micro-sized (the width and depth (height) of the flow path used for measurement are μm to mm). Order) is underway.

  For example, in Patent Document 2, an aperture (narrow portion) is formed in the middle of a micro channel (micro channel) for flowing blood as a sample, and impedance changes when blood cells pass through the aperture are measured on both sides of the aperture. A configuration in which detection is performed by two electrodes provided in the microchannel is disclosed. Moreover, in patent document 3, in order to remove the influence of the bubble accompanying the electrolysis at the time of voltage application (because the electric resistance changes when the bubble passes through the aperture, it becomes a measurement noise (false count)). A configuration is disclosed in which two electrodes for measurement are arranged in a flow path downstream from the aperture.

  The electrical resistance method is a technique for measuring blood cells in blood by utilizing the fact that a change in electrical resistance (or impedance) occurs when blood containing blood cells passes through an aperture. Specifically, the type of blood cells (red blood cells, white blood cells, and platelets) can be measured by detecting the pulse (signal) intensity according to the change in electrical resistance (impedance) proportional to the volume occupied by the blood cells. The number of blood cells can be measured by detecting the number of pulses.

Japanese Patent Laid-Open No. 4-303285 (released on October 27, 1992) JP 2002-277380 A (published September 25, 2002) JP 2005-62137 A (published March 10, 2005)

  However, in the techniques of Patent Documents 2 and 3, bubbles are generated in the electrode due to electrolysis with respect to the sample as the voltage is applied to the sample, but there is a problem that measurement accuracy is reduced due to the influence of the bubbles. It was.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is to realize high measurement accuracy without causing an increase in the amount of sample in particle measurement in a sample using an electric resistance method. An object of the present invention is to provide a micronized particle measuring apparatus.

  In order to solve the above problems, a particle measuring apparatus according to the present invention is a particle measuring apparatus capable of measuring particles contained in the sample by applying a voltage to the sample. At least two electrodes for applying a voltage to the sample, and a measurement unit for measuring particles contained in the sample by detecting electrical resistance or impedance when a voltage is applied to the sample, A sample introduction unit for introducing a sample into the apparatus, and at least one flow path through which the sample flows, connected to the measurement unit and the sample introduction unit. It includes a specific electrode that is any one of the electrodes.

  According to the above configuration, in the particle measuring apparatus, the measurement unit measures the particles contained in the sample by detecting the electrical resistance or impedance when a voltage is applied to the sample by at least two electrodes. .

  Here, for example, in the techniques of Patent Documents 2 and 3, since the electrode is provided in the flow channel, bubbles generated when a voltage is applied to the electrode flow into the measurement unit together with the sample flowing through the flow channel. End up. In particular, when the flow path is micronized, bubbles generated inside the flow path are difficult to escape from the flow formed by the sample, so that the inflow becomes significant. On the other hand, in the present invention, a sample introduction unit different from a channel (for example, a microchannel) is provided, and the specific electrode is provided in the sample introduction unit. For this reason, bubbles are generated inside the sample introduction part, and at least a part of the bubbles can be retained inside the sample introduction part. That is, it is possible to make it difficult for bubbles to enter the above flow, and to suppress the inflow to the measurement unit.

  Therefore, in comparison with the conventional case where electrodes are arranged in the flow path, it is possible to suppress the inflow of bubbles generated at the electrodes into the measurement unit. In addition, at least air bubble coating on the flow path can be suppressed. Therefore, the particle measuring apparatus of the present invention can perform highly accurate particle measurement.

  In the particle measuring apparatus according to the present invention, the sample introduction unit includes a sample introduction port through which the sample can be introduced into the sample introduction unit, and the sample introduction port includes the specific electrode and the sample. It is preferable to be provided between the introduction portion and the connection region where the flow path is connected.

  According to the said structure, a sample is introduce | transduced from a sample inlet and is derived | led-out from said connection area | region to a measurement part. Further, the sample introduction port is provided between the specific electrode and the connection region. That is, the specific electrode is provided at a location different from the flow of the sample from the sample introduction port to the connection region. For this reason, it can prevent that the bubble which generate | occur | produced in the specific electrode flows into a measurement part with a sample.

  In the particle measuring apparatus according to the present invention, when the distance in the vertical direction toward the top of the flow channel facing the bottom with respect to the bottom of the flow channel is defined as the depth of the sample introduction unit and the flow channel The depth of the sample introduction part is preferably longer than the depth of the flow path.

  According to the above configuration, since the cross-sectional area of the sample introduction portion in the vertical direction is larger than the cross-sectional area of the flow path, bubbles generated at the specific electrode can be reliably retained inside the sample introduction portion. That is, it is possible to more reliably suppress the entry of bubbles into the flow.

  In the particle measuring apparatus according to the present invention, the ratio of the sample amount in the sample introduction part when the sample is introduced into the sample introduction part with respect to the volume of the sample introduction part is 1 / 50,000 or more and 0.9 or less. It is preferable that

  According to the said structure, since a gas layer can be formed in the inside (upper part) of a sample introduction part after sample introduction, the bubble which generate | occur | produced at the electrode reaches | attains the said gas layer by buoyancy, and is defoamed. For this reason, it can prevent that the bubble which generate | occur | produced in the specific electrode flows into a measurement part with a sample.

  In the particle measuring apparatus according to the present invention, it is preferable that an opening for opening bubbles generated from the specific electrode into the atmosphere is provided on the upper surface of the sample introduction unit.

  According to the said structure, since the bubble which generate | occur | produced from the specific electrode is open | released in air | atmosphere through an opening part, it can prevent that the said bubble flows in into a measurement part with a sample.

  In the particle measuring apparatus according to the present invention, it is preferable that the opening is disposed on a vertical line of the specific electrode.

  Since the opening is arranged on the vertical line of the specific electrode, the bubbles that have moved from the specific electrode to the upper part of the sample introduction unit due to buoyancy can be surely escaped to the outside of the particle measuring apparatus.

  In the particle | grain measuring apparatus which concerns on this invention, it is preferable to provide the voltage application means connected to the said electrode.

  Since the voltage applying means can apply a voltage to the sample (or particles contained therein) via the electrodes, the measurement of particles can be realized by detecting electric resistance or impedance.

  The particle measuring apparatus according to the present invention is a particle measuring apparatus capable of measuring particles contained in the sample by applying a voltage to the sample, and at least 2 for applying a voltage to the sample. Two electrodes, a measurement unit for measuring particles contained in the sample by detecting electrical resistance or impedance when a voltage is applied to the sample, and introducing the sample into the apparatus. And at least one channel through which the sample flows, connected to the measurement unit and the sample introduction unit, and the sample introduction unit is any one of the electrodes The configuration includes a specific electrode.

  Therefore, the particle measuring apparatus of the present invention has an effect of being able to perform highly accurate particle measurement.

(A) is a top view which shows an example of schematic structure of the particle | grain measuring apparatus which concerns on one Embodiment of this invention, (b) is the sectional drawing. It is a perspective view which shows an example of the whole schematic structure of the said particle | grain measuring apparatus. (A)-(g) is a top view which shows the example of arrangement | positioning of the conductor with which the said particle | grain measuring apparatus is provided. (A)-(f) is a top view which shows the various shapes of the flow path with which the said particle | grain measuring apparatus is provided. It is a top view which shows the further modification of the flow path with which the said particle | grain measuring apparatus is provided. It is a top view which shows the further modification of the flow path with which the said particle | grain measuring apparatus is provided. It is a top view which shows an example of the shape of the sample introduction part with which the said particle | grain measuring apparatus is equipped, and a sample derivation | leading-out part. It is a figure which shows the modification of the said particle | grain measuring apparatus, and is a top view of the said particle | grain measuring apparatus in the case of providing only one said flow path. (A) is a top view which shows the further another example of schematic structure of the said particle | grain measuring apparatus, (b) is the sectional drawing. (A) is a top view which shows schematic structure of the particle | grain measuring apparatus based on one Embodiment of this invention used when the measurement of particle | grains is performed, (b) is when particle | grain measurement is performed It is a graph which shows the measurement result obtained. It is a figure for demonstrating that a big resistance change rate is obtained in the said particle | grain measuring apparatus. (A) is a top view which shows an example of schematic structure of the particle | grain measuring apparatus which concerns on another one Embodiment of this invention, (b) is the sectional drawing. It is a perspective view which shows schematic structure of the sample introduction part with which the said particle | grain measuring apparatus is provided. (A) is a top view which shows another example of schematic structure of the said particle | grain measuring apparatus, (b) is the sectional drawing. It is a perspective view which shows schematic structure of the sample introduction part with which the said particle | grain measuring apparatus is provided. (A) is a top view which shows the modification of schematic structure of the said particle | grain measuring apparatus, (b) is the sectional drawing. (A) is a top view which shows the further modification of schematic structure of the said particle | grain measuring apparatus, (b) is the sectional drawing. (A) is a top view which shows an example of schematic structure of the particle | grain measuring apparatus which concerns on another another embodiment of this invention, (b) And (c) is the sectional drawing. (A)-(c) is a top view which shows another example of schematic structure of the said particle | grain measuring apparatus. (A)-(d) is a top view which shows the modification of the said particle | grain measuring apparatus.

  Embodiments of the present invention will be described with reference to FIGS.

  In each embodiment, the particles are not limited to spherical beads and blood cells, but also include particles that are dispersed as colloids in samples other than spherical, such as dust, dust, cells, proteins, and nucleic acids.

  Further, in each embodiment, the particle measurement may be performed as long as the particle is measured by detecting electric resistance or impedance. The presence or absence of particles in the sample, the counting of the number of particles contained in the sample, the mass of the sample The concentration of particles relative to (or volume), the size of particles contained in the sample, and the like are included.

  In addition, the samples used in each embodiment include all those that can be measured by electrical resistance or impedance. For example, a gas sample such as air or gas, an aqueous solution, a liquid sample such as blood, or a high gel such as a gel. Examples include molecular solution samples.

  Further, the “depth” of each part is a vertical distance from the bottom (bottom) of the flow path to the top (top) of the flow path facing the bottom, and the “length” of each part is This is the distance in the main direction (flow direction) when the sample flows through the channel, and the “width” of each part is the distance in the direction perpendicular to the “depth” and “length” of each part. is there. Regarding the “depth” of each part, if the bottom of the channel and the bottom of the other members are not on the same plane, it is assumed that the bottom of the member is formed on the same plane as the bottom of the channel The above distance is defined as “depth”.

  In the following description, the particle measuring devices 15, 15a, and 15b are described on the assumption that electrical resistance or impedance detection (resistance measurement) is performed on a sample containing particles, but the present invention is not limited to this, and particles are not included. It is also possible to measure the resistance of a sample (for example, a standard sample). When measuring the resistance of a sample that does not contain particles, for example, the presence or absence of particles in the sample is confirmed by taking the difference between the measured electrical resistance values.

[Embodiment 1]
One embodiment of the present invention will be described below with reference to FIGS. The present invention is not limited to the following description.

<Outline of the present embodiment>
In general, in bulk measurement, since the electrical resistance of the aperture is dominant with respect to the electrical resistance between electrodes arranged in the bulk (wide space), a large resistance change rate is obtained when a blood cell passes through the aperture. However, in a conventional particle measuring device (for example, a blood cell counter) in which the flow path connected to the aperture is micro-sized, the electrical resistance in a portion (for example, the flow path) other than the aperture between the electrodes becomes so large that it cannot be ignored. Thereby, even if the particles pass through the aperture, the resistance change rate at the aperture with respect to the entire electrical resistance including the portion is reduced.

  In order to prevent this resistance change rate from becoming small, it is conceivable to form a wide and deep area other than the aperture, but this is difficult for fabrication and increases the amount of sample required. End up.

  As described above, when the particle measuring apparatus is miniaturized for the purpose of reducing the amount of the sample, there is a problem that the intensity of the obtained measurement signal is weakened.

  In order to solve the above-described problem, the particle measuring apparatus according to the present embodiment includes at least one conductor that suppresses electrical resistance or impedance generated between any one of the plurality of electrodes and the measurement unit. It is the composition provided. Thereby, the particle measuring apparatus can prevent the intensity of the measurement signal (signal) from being weakened, that is, can obtain a measurement signal having a high intensity, and therefore can measure particles with high accuracy.

<Overall structure of particle measuring apparatus 15>
First, a schematic configuration of the particle measuring apparatus 15 according to the present embodiment will be described with reference to FIG. FIG. 2 is a perspective view showing an example of the overall schematic configuration of the particle measuring device 15.

  As shown in FIG. 2, the particle measuring device 15 mainly includes electrodes 1a and 1b, a measuring unit 2, an upstream channel 4a, a downstream channel 4b, a conducting wire 5, a sample introduction unit 6a, and a sample. A lead-out part 6 b and a connector 7 are provided.

  Each of the electrodes 1a and 1b is connected (coupled) to the connector 7 via the conducting wire 5. The connector 7 is configured to be connected to a voltage application device (voltage application means) (not shown).

  When the particle measuring device 15 is connected to the voltage applying device, the voltage applying device applies a predetermined voltage to the electrodes 1a and 1b, and is introduced into the particle measuring device 15 through the electrodes 1a and 1b. A voltage can be applied to the sample. That is, the particle measuring device 15 can measure particles contained in the sample by the electric resistance method.

  In FIG. 2, the connector 7 is provided and can be connected to the particle measuring device 15. However, the configuration is not limited thereto, and the particle measuring device 15 may include a voltage applying device.

  Further, in the particle measuring device 15, when the sample passes through the measuring unit 2 or the sample is placed on the measuring unit 2, the electrical resistance or impedance when the voltage is applied to the sample (hereinafter, mainly, The case of electrical resistance will be described as an example). That is, the particle measuring device 15 can measure particles in the measuring unit 2 regardless of whether the sample is flowing or in a stationary state.

  For example, in the particle measuring device 15, the sample introduced from the sample introduction unit 6a is carried to the measurement unit 2 via the upstream flow path 4a, and then from the sample lead-out unit 6b via the downstream flow path 4b. 15 to the outside. The electrodes 1a and 1b, the measurement unit 2, the upstream channel 4a, the downstream channel 4b, the sample introduction unit 6a, and the sample lead-out unit 6b will be described in detail below.

  Further, the particle measuring apparatus 15 according to the present embodiment includes conductors 3a and 3b that suppress electrical resistance (its absolute value) generated between one of the electrodes 1a and 1b and the measurement unit 2. As described above, it is possible to measure particles with high accuracy. The reason why high-precision particle measurement is possible when the particle measuring device 15 includes the conductor 3a or 3b will be described in detail below.

<Method for Manufacturing Particle Measuring Device 15>
Here, based on FIG. 2, an example of the manufacturing method of the particle | grain measuring apparatus 15 is demonstrated.

  Moreover, the said structure of the particle | grain measuring apparatus 15 is produced by bonding after processing the board | substrates 8a and 8b which consist of glass, resin, etc., for example. That is, the substrate 8b functions as a lid for the substrate 8a.

  In this case, the measurement unit 2, the upstream flow path 4a, and the downstream flow path 4b are formed by cutting the substrate 8a by wet etching / dry etching, machining, or the like. When the conductors 3a and 3b are metal, the electrodes 1a and 1b and the conductors 3a and 3b are formed on the substrate 8a by using, for example, sputtering or lift-off. When the conductors 3a and 3b are carbon, the conductors 3a and 3b are formed on the substrate 8a by using, for example, screen printing. In the case where the conductors 3a and 3b are non-flowable electrolytes, the positions where the conductors 3a and 3b are formed are filled with a non-flowable electrolyte, or at least a part thereof is cured after filling as a flowable electrolyte (for example, thermosetting). For example, a photocurable resin or a photocurable resin is used). Moreover, the sample introduction part 6a and the sample derivation | leading-out part 6b are formed by machining with respect to the board | substrates 8a and 8b, for example. At this time, a through hole (a sample introduction port 9a and a sample introduction port 9a shown in FIG. 12) is formed on the upper surface of the substrate 8b (the surface opposite to the surface facing the substrate 8a) at a position corresponding to the positions of the sample introduction unit 6a and the sample extraction unit 6b. A sample outlet 9b) may be formed.

  In the above description, the method of forming the particle measuring device 15 by bonding the substrates 8a and 8b has been described. However, the present invention is not limited to this, and the particle measuring device 15 is applied only to the substrate 8a. It is also possible to form. Further, the electrode substrate on which the electrodes 1a and 1b and the conductors 3a and 3b are formed is bonded to the flow path substrate on which the measurement unit 2, the upstream channel 4a, the downstream channel 4b, the sample introduction unit 6a, and the sample outlet unit 6b are formed. By doing so, the particle measuring device 15 may be formed.

<Specific Configuration of Particle Measuring Device 15>
Next, the schematic configuration of the particle measuring device 15 will be described in more detail with reference to FIG. 1A is a top view showing an example of a schematic configuration of a particle measuring apparatus according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view thereof.

  As described above, the particle measuring device 15 includes the electrodes 1a and 1b, the measurement unit 2, the upstream flow channel 4a, the downstream flow channel 4b, the sample introduction unit 6a, and the sample derivation unit 6b. As shown in FIGS. 1A and 1B, a measuring unit 2 is provided between the electrodes 1a and 1b via an upstream channel 4a and a downstream channel 4b. That is, one end of each of the upstream flow path 4a and the downstream flow path 4b is connected to the measurement unit 2.

  Also, conductors 3a and 3b are provided on almost the entire lower surface (bottom surface) of the upstream channel 4a and the downstream channel 4b, respectively. For example, as shown in FIG. 3C, the conductors 3a and 3b may be provided in at least a part of the upstream flow path 4a and the downstream flow path 4b, respectively. In the present invention, the intensity of the measurement signal is defined not only by the structure of the measurement unit 2 but also by the relationship between the structure of the measurement unit 2 and the arrangement of the conductors 3a and 3b. Therefore, since the conductors 3a and 3b are provided as described above, the strength of the measurement signal is weakened due to the influence of the material and processing accuracy of the substrates 8a and 8b forming the particle measuring device 15. Can be prevented.

  However, the upstream flow path 4 a and the downstream flow path 4 b are not necessarily used for flowing the sample to the measurement unit 2, and may be used for placing the sample on the measurement unit 2. That is, the upstream flow path 4a and the downstream flow path 4b do not necessarily have a function as a flow path as long as the sample can be introduced (placed) on the measurement unit 2. Moreover, the upstream flow path 4a and the downstream flow path 4b do not necessarily have a linear shape, and may have a curved shape such as an S shape as shown in FIG. In addition, when the particle measuring device 15 includes two channels such as the upstream channel 4a and the downstream channel 4b, a V-shape as shown in FIG. It may have a staircase shape as shown in FIG. 4 and a U-shape as shown in FIG.

  The plane (cross-sectional) shape perpendicular to the sample flow direction in the upstream channel 4a and the downstream channel 4b does not have to be a rectangle, but a shape (such as a circle, an ellipse, or a triangle) that allows the sample to flow ( Or the shape which can be mounted in the measurement part 2) may be sufficient. In the case of a rectangle, the surface on which the sample flows (the surface on which the conductors 3a and 3b are arranged in FIG. 1B) is the bottom surface, and the surface facing the bottom surface is the top surface. On the other hand, when the shape is not rectangular, the regions of the upstream flow path 4a and the downstream flow path 4b corresponding to the bottom surface and the top surface are the bottom and the top, respectively.

  1 illustrates a configuration in which the particle measuring device 15 includes the upstream flow path 4a and the downstream flow path 4b. However, the configuration is not limited thereto, and for example, as illustrated in FIG. A configuration including only the conductor 3a) may be employed. That is, the particle measuring device 15 only needs to include at least one conductor that suppresses an electrical resistance generated between one of the two electrodes 1a and 1b and the measuring unit 2. Moreover, the particle | grain measuring apparatus 15 should just be provided with the at least 1 flow path through which the sample flows (electrically) connected to the measurement part 2 and either one of the two electrodes 1a and 1b. .

  Moreover, in FIG. 1 (a) and (b), the sample introduction part 6a and the sample derivation | leading-out part 6b are provided. The sample introduction part 6a is connected to the other end of the upstream flow path 4a, and the electrode 1a is disposed in a part of the inside thereof. The sample lead-out part 6b is connected to the other end of the downstream flow path 4b, and the electrode 1b is disposed in a part of the inside thereof. Note that the sample introduction unit 6a and the sample extraction unit 6b as illustrated in FIG. 1 are not necessarily provided as long as the sample can be introduced (placed) in the measurement unit 2. Further, it is not necessary to provide both the sample introduction unit 6a and the sample derivation unit 6b. For example, in the case of the particle measuring apparatus 15 for the purpose of performing one particle measurement, only the sample introduction unit 6a is provided. Just do it. For example, when the sample is placed on the measurement unit 2 and particle measurement is performed, it is only necessary to include one introduction / derivation unit.

  Hereinafter, the configuration of each unit will be described more specifically based on the configuration of FIGS.

  Each of the electrodes 1a and 1b is for applying a voltage to the sample in order to detect measurement of particles in the sample as electric resistance (or change in electric resistance). That is, the electrodes 1 a and 1 b are for applying a voltage to the sample introduced into the measuring unit 2.

  As described above, the electrodes 1a and 1b are provided, for example, in a part (for example, the lower surface) of the sample introduction unit 6a and the sample extraction unit 6b, and are connected to an external voltage application device (not shown). The electrodes 1a and 1b are not limited to the shapes arranged in the sample introduction part 6a and the sample lead-out part 6b. For example, as shown in FIG. 2, the electrodes 1a and 1b may be inserted into a sample introduced as a liquid.

  Examples of the material for the electrodes 1a and 1b include metals such as gold, platinum, copper, and aluminum, carbon, conductive polymers, and the like, and gold and platinum are particularly preferable because corrosion due to the sample is small.

  In the present embodiment, the configuration in which the particle measuring device 15 includes the electrodes 1a and 1b is described. However, the present invention is not limited to this. For example, an electrode group that functions as the electrode 1a is provided in the sample introduction unit 6a. The lead-out part 6b may be provided with an electrode group that functions as the electrode 1b. In other words, the particle measuring device 15 includes at least two electrodes.

  The measurement unit 2 is an area where particles contained in a sample are measured by detecting an electrical resistance when a voltage is applied to the sample, and forms an aperture. The width of the measurement unit 2 (the vertical direction of the paper surface in FIG. 1A) is 1-1000 μm, preferably 1-100 μm, and the depth (the direction perpendicular to the paper surface in FIG. 1A) is 1-1000 μm. The length (the left-right direction of the paper surface in FIG. 1A, the direction parallel to the line AA ′) is preferably 0.1 to 5000 μm.

  The upstream flow path 4a and the downstream flow path 4b form part of the flow path through which the sample flows, and their width is 1 to 5000 μm, preferably 1 to 1000 μm, and the depth is 1 to 1000 μm, Preferably it is 1-100 micrometers. Moreover, the upstream flow path 4a and the downstream flow path 4b may have a branched structure as shown in FIGS. 4 (e) and (f), for example.

  Moreover, although the cross-sectional shape of the measurement part 2, the upstream flow path 4a, and the downstream flow path 4b is a rectangular shape in Fig.1 (a), it is not restricted to this, and other circular shapes, elliptical shapes, etc. may be sufficient. Good.

  Here, in order to prevent the clogging of particles in the measurement unit 2, the upstream channel 4a, and the downstream channel 4b, the width and depth of the measurement unit 2, the upstream channel 4a, and the downstream channel 4b described above are respectively Preferably it is larger than the maximum diameter. Furthermore, in order to increase the resistance change rate when passing through the particle, the cross-sectional area of the measurement unit 2 (for example, in the case of a rectangular shape, width x depth) is the maximum cross-sectional area of the particle to be measured (for example, in the case of a spherical shape, It is preferable that the ratio of the cross-sectional area of the measurement unit 2 to the cross-sectional area of the particles is 1 to 15 and preferably 10 or less.

  The sample introduction part 6a is for introducing a sample into the apparatus itself, specifically for introducing the sample into the measurement part 2 via the upstream flow path 4a. The upstream flow path 4a and the measurement part 2 are connected to each other. The connection area is different from the connected area. The sample lead-out part 6b is for leading the sample from the downstream flow path 4b to the outside of the particle measuring device 15, and is a connection area different from the area where the downstream flow path 4b and the measurement part 2 are connected. Connected with. Thereby, the introduction / derivation of the sample with respect to the particle measuring device 15 can be performed efficiently. Moreover, the width | variety of each of the sample introduction part 6a and the sample derivation | leading-out part 6b is 1-50000 micrometers, the depth is 1-50000 micrometers, and length is 1-50000 micrometers.

  For example, in FIG. 1A, one end of the upstream flow path 4a is connected to the measurement unit 2 and the other end is connected to the sample introduction unit 6a in the direction parallel to the A-A ′ line. Similarly, one end of the downstream flow path 4b is connected to the measurement unit 2, and the other end is connected to the sample derivation unit 6b. In other words, the upstream flow path 4a is disposed so as to be connected to the upstream side of the measurement unit 2, that is, the sample introduction part 6a on the side where the sample is introduced into the measurement unit 2, and the downstream flow path 4b is It arrange | positions so that it may connect with the sample derivation | leading-out part 6b of the downstream of the measurement part 2, ie, the sample derivation | leading-out from the measurement part 2. Thereby, the introduction / derivation of the sample with respect to the measurement unit 2 can be performed efficiently.

  Further, a configuration may be adopted in which a tube is inserted into the sample introduction unit 6a and the sample lead-out unit 6b, and a sample (liquid) is introduced from the outside of the particle measuring device 15, or the sample is led out to the outside.

  The conductors 3a and 3b reduce the electrical resistance of the portion other than the measurement unit 2 (in this embodiment, the upstream flow channel 4a and the downstream flow channel 4b), and the measurement signal (resistance change rate associated with the passage of particles through the measurement unit 2). Is formed between the electrodes 1a and 1b and the measuring section 2 (in this embodiment, formed in the upstream flow path 4a and the downstream flow path 4b). Thereby, the influence of the electrical resistance between electrode 1a, 1b and the measurement part 2 can be excluded as much as possible.

  The material of the conductors 3a and 3b is preferably a substance having higher conductivity than that of the sample, and examples thereof include metals, carbon, conductive polymers, and non-fluid electrolytes. Examples of the metal include aluminum, zinc, chromium, iron, nickel, tin, copper, silver, platinum, gold, palladium, rhodium, iridium, and tungsten. Examples of carbon include glassy carbon, pyrolytic graphite, carbon paste, and carbon fiber. Examples of the conductive polymer include polyacetylene, polyparaphenylene, polyaniline, polythiophene, polyparaphenylene vinylene, and the like. Examples of non-fluid electrolytes include solid electrolytes such as chloride ion conductive solid electrolytes, β alumina, and stabilized zirconia, and liquids such as salt bridges (agarose containing potassium chloride, ammonium nitrate, or lithium acetate), potassium chloride, and the like. Examples thereof include a gel substance containing a liquid electrolyte such as polyvinyl chloride containing an electrolyte or polyacrylamide. As shown in FIGS. 4E and 4F, when a non-fluid electrolyte is used as the conductors 3a and 3b, the liquid electrolyte is filled in the branch paths 24a and 24b and the branch path is formed with a gel substance. It is also possible to seal both ends (first branch point 241 and second branch point 242) of 24a and 24b.

  The conductors 3a and 3b have a length in the direction connecting the electrodes 1a and 1b and the measurement unit 2 of 1 mm or more and 10 cm or less. In this case, the conductors 3a and 3b can be provided in the particle measuring device 15 in consideration of the manufacturing process. That is, when the conductors 3a and 3b are metal and carbon, the particle measuring device 15 can be easily manufactured by sputtering, lift-off, screen printing, etc. by setting the length to 1 mm or more. Further, by arranging the conductors 3a and 3b, the signal intensity of particle measurement can be effectively increased (described later). Moreover, the size (chip formation) of the particle | grain measuring apparatus 15 can be achieved by making the conductors 3a and 3b into 10 cm or less.

  The conductors 3a and 3b are not directly connected to the electrodes 1a and 1b and the voltage application device (conduct through the sample). That is, the conductors 3a and 3b are provided apart from the electrodes 1a and 1b. Thereby, the influence of the electrical resistance between the electrodes 1a and 1b and the measuring unit 2 that the conductors 3a and 3b give to the measurement of the particles in the measuring unit 2 can be suppressed.

  Further, as shown in FIG. 1B, the conductors 3a and 3b are not necessarily formed on the lower surfaces of the upstream flow path 4a and the downstream flow path 4b, respectively. For example, when the two conductors 3a and 3b are respectively disposed on the lower surfaces of the upstream flow path 4a and the downstream flow path 4b (the same surface corresponding to the two conductors), the electric lines of force generated in each of the conductors 3a and 3b are substantially semicircular. Become. Since the electric lines of force are mainly concentrated in the depth direction of the measurement unit 2, when the distance between the two conductors 3a and 3b is short, there is a possibility that an electric field strength may be generated in the depth direction in the measurement unit 2. At this time, when the particles flow above the measurement unit 2, the signal intensity may be lower than when the particles flow below the measurement unit 2 (strong electric field) because the upper part is a weak electric field.

  In order to prevent the signal strength from decreasing, for example, when the conductor 3a is disposed on the lower surface of the upstream flow path 4a, it is preferable to dispose the conductor 3b on the upper surface of the downstream flow path 4b. You may arrange in both. On the other hand, the arrangement relationship may be reversed between the upstream flow path 4a and the downstream flow path 4b. Furthermore, the conductor 3a may be provided on both the upper surface and the lower surface of the upstream flow path 4a, and the conductor 3b may be provided on both the upper surface and the lower surface of the downstream flow path 4b. The conductors 3a and 3b may be provided on the side surfaces of the upstream channel 4a and the downstream channel 4b, respectively.

  In other words, the conductor 3a or 3b provided on one surface forming one of the upstream flow path 4a and the downstream flow path 4b forms one of the other flow paths corresponding to the one surface. It is provided at least on the opposing surface. Thus, by arranging at least one of the conductors on the opposing surface, the electric lines of force can be made more uniform in the measurement unit 2, and the measurement unit 2 can be used even when the distance between the conductors 3a and 3b is short. It is possible to maintain a high signal intensity associated with the passage of particles. That is, this conductor arrangement effectively applies an electric field to the particles in the sample flowing through the upstream flow path 4a and the downstream flow path 4b, so that a strong measurement signal can be obtained and the above-described decrease in signal strength is prevented. it can.

  Therefore, by using the particle measuring device 15 of the present embodiment, in the measurement of particles in a sample using the electric resistance method, a high measurement signal intensity (S / N ratio) is obtained without causing an increase in the amount of the sample. ) And measurement of particles with high measurement accuracy. Therefore, for example, the particle measuring device 15 can be provided as a blood cell measuring device using a very small amount of blood as a sample and having a micro-channel flow path.

  Next, modified examples of the shapes of the conductors 3a and 3b, the upstream flow path 4a, the downstream flow path 4b, the sample introduction part 6a, and the sample lead-out part 6b will be described with reference to FIGS.

(Conductor shape)
First, modified examples of the shapes of the conductors 3a and 3b will be described with reference to FIGS.

  As shown in FIG. 3 (a), the conductors 3a and 3b may be formed not only in the upstream flow path 4a and the downstream flow path 4b but also in a part of the measurement unit 2, or the sample introduction unit 6a and It may also be formed on a part of the sample outlet 6b. In the case of this configuration, it is possible to increase the resistance change rate measured when the particles pass through the measurement unit 2.

  Moreover, as shown in FIG.3 (b), the width | variety of the conductors 3a and 3b may be larger than the width | variety of the upstream flow path 4a and the downstream flow path 4b. In the case of this configuration, the alignment in the bonding of the electrode substrate and the flow path substrate described above becomes easy.

  Further, as shown in FIG. 3C, the widths of the conductors 3a and 3b may be smaller than the widths of the upstream flow path 4a and the downstream flow path 4b. In the case of this configuration, since the conductors 3a and 3b do not exist between the adhesion surface of the flow path substrate and the electrode substrate in the above-described bonding of the electrode substrate and the flow path substrate, the adhesion of these substrates is facilitated. .

  As shown in FIG. 3D, the widths of the conductors 3a and 3b do not have to be uniform. For example, the widths of the conductors 3a and 3b are closer to the sample introduction part 6a, the sample lead-out part 6b, and the measurement part 2. It is good also as a structure which is large and the width | variety is small in another area | region.

  Further, as shown in FIG. 3E, the conductors 3a and 3b are not necessarily formed inside the upstream flow path 4a and the downstream flow path 4b. That is, the conductors 3a and 3b are formed inside the upstream flow path 4a and the downstream flow path 4b on the side close to the sample introduction part 6a, the sample lead-out part 6b, and the measurement part 2, respectively. 4a and the downstream flow path 4b may be connected outside. In other words, the conductors 3a and 3b are provided separately in the upstream channel 4a and the downstream channel 4b, and are connected to the outside of the upstream channel 4a and the downstream channel 4b.

  In the case of this configuration, it is possible to prevent the conductors 3a and 3b provided in the upstream channel 4a and the downstream channel 4b from being deteriorated due to the sample flowing through the upstream channel 4a and the downstream channel 4b. Thereby, the long life particle | grain measuring apparatus 15 is realizable, and the particle | grain measuring apparatus 15 can be used continuously or repeatedly. For example, the deterioration phenomena of the conductors 3a and 3b include oxidation of the conductor due to contact with the sample, and adsorption of proteins contained in the blood to the conductor when the sample is blood.

  Further, for example, in the upstream flow path 4a, conductors 3a that are separated in the inside (two places in FIG. 3E) are connected to the outside of the upstream flow path 4a. For this reason, the influence of the electrical resistance in the upstream flow path 4a on the particle measurement can be suppressed as in the case where the conductor 3a is provided on the entire lower surface of the upstream flow path 4a.

  Further, for example, in the upstream flow path 4a, an electrical sensor is disposed in a space between two conductors 3a provided in the upstream flow path 4a so as to be spaced apart (region in the upstream flow path 4a where no conductor exists). can do. In this case, by receiving the detection results from these sensors, it is possible to measure a plurality of items by measuring particles with higher accuracy than when only the conductor 3a is provided, or by measuring particles once. . Examples of the electrical sensor include a flow rate sensor, a fluid detection sensor, and an electrochemical detection sensor for analyzing an analyte (such as ions and proteins).

  In the above description, the upstream flow path 4a is described as an example, but the same can be said for the downstream flow path 4b.

  3 (f) and 3 (g), the conductors 3a and 3b are arranged in the length direction of the upstream flow path 4a and the downstream flow path 4b, or in the width direction of the upstream flow path 4a and the downstream flow path 4b. It may be formed in a stripe shape.

  3A to 3G, the conductors 3a and 3b are provided apart from each other (not connected to each other and conducted through the sample), as in FIG. 1A. In this case, the shortest straight line distance between the conductors 3a and 3b is 0.1 to 1000 μm, preferably 0.1 to 100 μm. In other words, the conductor 3a provided in the upstream flow path 4a and the conductor 3b provided in the downstream flow path 4b are provided separated by at least 0.1 μm or more and 1000 μm or less. By providing such a separation, a strong measurement signal (a large resistance change rate in the measurement unit) can be obtained with a simple manufacturing method.

  In addition, it is preferable that the length of the conductors 3a and 3b is 0.1 μm or more from the viewpoint of accuracy in manufacturing the conductor. In general, assuming that the density of the electric lines of force generated in each of the conductors 3a and 3b is equalized, basically, the closer the distance between the conductors 3a and 3b, the more the particles pass through the measurement unit 2. The signal intensity (resistance change rate in the measurement unit 2) increases (because the resistance of the entire system decreases). For this reason, if the conductors 3a and 3b are separated too much, the signal strength may be lowered. In consideration of this point, the distance is preferably 1000 μm or less.

  Also, for example, when the conductor 3a or 3b is provided on both the upper surface and the lower surface of the upstream flow path 4a or the downstream flow path 4b, the direction in which the conductor on the upper surface and the conductor on the lower surface are not connected In the depth direction. At this time, when the conductors 3 a and 3 b are formed up to the measurement unit 2, the conductors 3 a and 3 b are disposed on a part of the measurement unit 2 and on both the upper surface and the lower surface of the measurement unit 2.

  In addition to the above, the conductors 3a and 3b may be inserted into the inside of the upstream flow path 4a and the downstream flow path 4b from the outside (for example, the sample introduction part 6a, the sample lead-out part 6b, etc.). Moreover, the conductors 3a and 3b do not need to have a linear shape. For example, in accordance with the shapes of the upstream flow path 4a and the downstream flow path 4b shown in FIGS. It may have a curved shape such as a letter shape.

(Shape of upstream flow path 4a and downstream flow path 4b)
Next, modified examples of the shapes of the upstream flow path 4a and the downstream flow path 4b will be described with reference to FIGS.

  As shown in FIGS. 4A to 4D, the measurement unit 2, the upstream flow path 4a, and the downstream flow path 4b do not need to be connected in a straight line. For example, as shown in FIG. As shown, the upstream flow path 4a and the downstream flow path 4b may be curved in an S shape. Moreover, the V shape of FIG.4 (b), the staircase shape shown in FIG.4 (c), and the U-shape shown in FIG.4 (d) may be sufficient.

  Further, as shown in FIGS. 4E and 4F, the upstream flow path 4a and the downstream flow path 4b may have a branched structure. In this case, the branch path 24a branches from the upstream flow path 4a at the first branch point 241 on the electrode 1a side in the upstream flow path 4a and the second branch point 242 on the measurement unit 2 side in the upstream flow path 4a. The conductor 3a is preferably arranged in the branch path 24a.

  Moreover, it is preferable that the sample flowing through the upstream flow path 4a is not introduced into the branch path 24a. The design of the structure of the branch path 24a and the conductor so that the electrical resistance (absolute value) in the branch path 24a is lower than the electrical resistance of the upstream path 4a (the straight path in FIGS. 4 (e) and 4 (f)). By arranging 3a, it is possible to suppress the influence of electrical resistance in the upstream flow path 4a on the measurement of particles (described later).

  The structure of the branch path 24a includes making the width and / or depth of the branch path 24a larger than the width and / or depth of the upstream flow path 4a. However, when the conductivity of the conductor 3a is higher than the conductivity of the sample, the width and / or depth of the branch path 24a may be equal to or less than the width and / or depth of the upstream flow path 4a.

  In order to prevent the sample from being introduced into the branch path 24a, the conductor 3a is preferably the above-described non-fluidic electrolyte. Alternatively, the metal, carbon, and conductive polymer described above are disposed in the branch path 24a as a conductor 3a together with a fluid electrolyte such as saline, and the first branch point 241 and the second branch point 242 of the branch path 24a. It is good also as a structure sealed with non-flowable substances, such as a gel. By preventing the sample from being introduced into the branch path 24a, the volume of the sample used for the measurement is not affected by the increase in volume corresponding to the branch path 24a, so that measurement with a very small amount of sample is possible.

  Even when the sample is prevented from being introduced into the branch path 24a, the first branch point 241 and the second branch point 242 of the branch path 24a are electrically connected via the upstream flow path 4a (measurement unit 2) and the sample. Is electrically connected.

  In this way, by connecting the branch path 24a to the upstream flow path 4a and disposing the conductor 3a in the branch path 24a, a strong measurement signal (measurement) can be performed without affecting the upstream flow path 4a through which the sample flows. A large resistance change rate in the portion 2 can be obtained. It is also possible to increase the range of selection of the type of conductor 3a. In the above description, the upstream flow path 4a is described as an example, but the same can be said for the downstream flow path 4b.

  In FIGS. 4A to 4C, the conductors 3a and 3b are formed so as to include all of the upstream flow path 4a and the downstream flow path 4b, respectively, but not limited thereto, as described above, The structure provided in the inside along the shape of the upstream flow path 4a and the downstream flow path 4b may be sufficient. 4 (a) to (f), the conductors 3a and 3b are disposed in the entire region of the upstream flow path 4a and the downstream flow path 4b (the branch paths 24a and 24b in FIGS. 4 (e) and (f)), respectively. Although formed, as described above, a configuration provided in a part thereof may be used. Further, the shapes of the upstream flow path 4a and the downstream flow path 4b may be different from each other. For example, the upstream flow path 4a may have a S shape as shown in FIG. 4A, and the downstream flow path 4b may have a V shape as shown in FIG. 4B.

  4 (e) and (f), the conductors 3a and 3b are provided only in the branch path 24a and the branch path 24b, so that a strong measurement signal can be obtained and the range of selection of the types of the conductors 3a and 3b can be obtained. Is spreading. However, if this point is not taken into account, the conductors 3a and 3b may be provided not only in the branch path 24a and the branch path 24b but also in the upstream flow path 4a and the downstream flow path 4b, respectively.

(Other shapes)
Moreover, the shape of the conductors 3a and 3b, the upstream flow path 4a and the downstream flow path 4b, the sample introduction part 6a, and the sample lead-out part 6b as shown in FIGS.

  For example, as shown in FIG. 5, the upstream flow path 4a and the downstream flow path 4b have a notch shape on the measurement unit 2 side (a taper structure is formed when the upstream flow path 4a and the downstream flow path 4b are conical). In addition, the inner surface (surface on the side in contact with the sample) of each flow path may be gradually reduced to the size of the cross section of the measurement unit 2. In this case, the particles are not clogged before and after the measurement unit 2 (according to the stagnation of the flow) (regions connected to the upstream flow path 4a and the downstream flow path 4b), so that it is possible to measure particles with high accuracy. . At this time, the conductors 3a and 3b may also have the above-described notch shape so as to follow the shapes of the upstream flow path 4a and the downstream flow path 4b.

  Further, as shown in FIG. 6, the cross-sectional area of the measurement unit 2 is substantially the same as the cross-sectional areas of the upstream flow channel 4 a and the downstream flow channel 4 b (for example, the cross-sectional areas are equal or the upstream flow channel 4 a with respect to the measurement unit 2. The cross-sectional area ratio of the downstream flow path 4b may be 0.5 or more and 2 or less. In the present embodiment, even if the cross-sectional areas of the upstream flow path 4 a and the downstream flow path 4 b are substantially the same as the cross-sectional area of the measurement unit 2, the measurement signal (resistance change rate) is the electrical resistance in a region other than the measurement unit 2. Not affected (described later). For this reason, by making said cross-sectional area substantially the same, the sample amount required for the measurement of particle | grains can further be reduced.

  For example, as shown in FIG. 7, each of the sample introduction part 6a and the sample lead-out part 6b has a notch shape (tapered structure) on the upstream flow path 4a and the downstream flow path 4b side. The inner surface of the sample outlet 6b may be gradually reduced to the cross-sectional size of each flow path. In this case, since there is no clogging of particles due to the stagnation of the flow in the sample introduction part 6a and the sample lead-out part 6b, it is possible to measure particles with high accuracy.

  Further, as shown in FIG. 8, there are not necessarily two conductors and channels. For example, the conductor 3a is disposed in the upstream channel 4a, and the measuring unit 2 is disposed between the upstream channel 4a and the sample outlet 6b. It is good also as a structure to form. In addition, the conductor 3b may be disposed in the reverse configuration, that is, the downstream flow path 4b, and the measurement unit 2 may be formed between the downstream flow path 4b and the sample introduction section 6a.

<Further example (Part 1) of particle measuring device 15>
Next, another example of the particle measuring device 15 will be described with reference to FIG. FIG. 9 is a top view and a cross-sectional view showing still another example of the schematic configuration of the particle measuring device 15.

  As shown in FIG. 9A, the shape of the particle measuring device 15 when viewed from the top is the same as that shown in FIG. 1A, for example. However, as shown in FIG. The depth of the measuring unit 2 of the device 15 is shallower than the depth of the upstream flow path 4a and the downstream flow path 4b. For example, the depth is 1 to 500 μm, preferably 1 to 100 μm.

  When the upstream flow path 4a and the downstream flow path 4b are equal in depth to the measuring section 2, and the two conductors 3a and 3b are respectively disposed on the lower surfaces of the upstream flow path 4a and the downstream flow path 4b, the lines of electric force are substantially reduced. It becomes semicircular. In this case, as described above, the strength of the electric field is generated in the depth direction in the measurement unit 2, and the signal intensity of the particles flowing above the measurement unit 2 may be lower than the particles flowing below the measurement unit 2. By making the depth of the measurement unit 2 shallower than the depths of the upstream flow path 4a and the downstream flow path 4b, electric field lines can be made more uniform in the measurement unit 2, and the distance between the conductors 3a and 3b is short In this case, the signal intensity associated with the passage of particles in the measurement unit 2 can be kept high. That is, by this depth setting, it is possible to prevent the signal strength from decreasing.

<Sample measurement method>
Hereinafter, a method for measuring particles in a sample using the particle measuring device 15 according to the present embodiment will be described with reference to FIGS. FIG. 10 is a top view showing a schematic configuration of the particle measuring device 15 used when particles are measured, and a graph showing measurement results obtained at that time. FIG. 11 is a diagram for explaining that a large resistance change rate can be obtained in the particle measuring device 15. The particle measuring device 15 shown in FIG. 10A corresponds to the particle measuring device 15 shown in FIG. In the following description, the member numbers of the particle measuring device 15 shown in FIG. 10 may be used for convenience for the conventional particle measuring device (configuration without the conductor 3a (3b)).

  The particle measuring method according to the present embodiment can measure particles contained in a sample by applying a voltage to the sample. This particle measurement method includes an arrangement step of arranging a sample in the measurement unit 2 where measurement of particles contained in the sample is performed, a voltage application step of applying a voltage to the sample via at least two electrodes 1a and 1b, The measurement unit 2 includes a detection step of detecting electrical resistance or impedance. In the voltage application step, at least one conductor 3a (3b) that suppresses an electrical resistance or impedance generated between one of the two electrodes 1a and 1b and the measurement unit 2 is disposed. Done.

  By this method, as described above, it is possible to prevent the strength of the measurement signal indicating the electrical resistance (change thereof) in the measurement unit 2 from being weakened (increase the strength of the measurement signal), and therefore, highly accurate particle measurement. It can be performed.

  Moreover, the said arrangement | positioning process may be performed by flowing a sample to the measurement part 2 via the upstream flow path 4a and the downstream flow path 4b. In this case, particles in the sample can be continuously measured. The particle measuring method may further include an introducing step of introducing the sample from the sample introducing portion 6a connected to the upstream flow path 4a, and a step of deriving from the sample deriving portion 6b connected to the downstream flow path 4b. .

  In the measurement of particles in a sample by the electric resistance method or impedance method used in this embodiment, when a voltage is applied to the sample using at least two electrodes, particles (substantially insulators) are present in the sample. This is performed by utilizing the fact that the resistance (or impedance) between the electrodes due to the presence changes (increases) as compared to the case where there is no particle. In addition, when the sample is blood and the particles are blood cells, the blood cell type (red blood cells, white blood cells, and platelets) is measured by detecting the pulse (signal) intensity according to the change in electrical resistance (impedance) proportional to the volume occupied by the blood cells. The number of blood cells can be measured by detecting the number of pulses corresponding to the change.

In measuring the electrical resistance or impedance (change), the resistance change between the electrodes when a constant current is applied between the electrodes for measurement is expressed by the following equation (1), that is,
ΔV = I · ΔR (1)
Therefore, it is common to measure as a voltage change. Here, ΔV is a voltage change due to the presence or absence of particles, I is a constant current value, and ΔR is a resistance change due to the presence or absence of particles. In actual measurement, noise proportional to the magnitude of the applied voltage (fluctuation of the measured voltage value) is generated, so the S / N ratio is important in order to capture the voltage change as a measurable signal (measurement signal). ΔV / V (= ΔR / R, resistance change rate), which is the ratio between the initial voltage V and the voltage change amount, is important as a measurement signal detection index.

In general, the electrical resistance R is
R = ρ · L / S (2)
It is represented by Here, ρ is the electrical resistivity (reciprocal of conductivity) of the sample, L is the length of the resistor, and S is the cross-sectional area of the resistor.

In FIG. 10, when there are no conductors 3a and 3b (corresponding to a conventional micronized particle measuring apparatus), the electric resistance R1 between the electrodes 1a and 1b when there is no particle is expressed by the following equation (3). In addition,
R1 = R1 _6a + R1 _4a + R1 ₂ + R1 _4b + R1 _6b (3)
It becomes. Here, _{R1 6a} electrical resistance of the sample introduction portion 6a, _{R1 4a} electrical resistance of the upstream passage 4a, R1 ₂ is the electrical resistance of the measuring section 2, _{R1 4b} electrical resistance of the downstream flow path 4b, _{R1 6b} the sample It is an electrical resistance of the derivation | leading-out part 6b.

Since the sample introduction part 6a and the sample lead-out part 6b have a larger cross-sectional area than the upstream flow path 4a and the downstream flow path 4b, respectively, the electrical resistances R1 _6a and R1 _6b correspond to the upstream flow path 4a and the downstream flow path 4b. The electric resistances R1 _4a and R1 _4b and the electric resistance R1 ₂ of the measurement unit 2 are negligibly small (substantially, R1≈R1 _4a + R1 ₂ + R1 _4b ). When particles pass through the measurement unit 2, a part of the sample that is a conductor introduced into the measurement unit 2 is shielded by the particles that are substantially insulators, so that the electrical resistance in the measurement unit 2 increases. At this time, the electric resistance R1 ′ between the electrodes 1a and 1b is expressed by the following equation (4):
R1 ′ = R1 _6a + R1 _4a + R1 ₂ ′ + R1 _4b + R1 _6b (4)
It becomes. Here, R1 ₂ ′ is the electrical resistance of the measurement unit 2 when particles are present in the sample.

Therefore, in order to detect the presence of particles as a measurement signal, the following equation (5) indicating the rate of resistance change, that is,
ΔR1 / R1 = (R1'-R1 ) / R1 = (R1 2 '-R1 2) / R1
... (5)
Is a detection index.

Here, in the micronized conventional particle measuring apparatus, R1 _4a (electric resistance of the upstream flow path 4a) and R1 _4b (electric resistance of the downstream flow path 4b) included in the denominator R1 of the expression (5) are very high. Since it is large (the cross-sectional area of each micronized flow path is very small), there is a problem that the resistance change rate is small and it is difficult to obtain a measurement signal (being buried in noise). This is a serious problem particularly when small particles such as platelets (corresponding to 2 μm) in blood are detected simultaneously with red blood cells (corresponding to 8 μm). Since the measurement unit cannot be made smaller than the red blood cell size (red blood cells are clogged if it is reduced), it is difficult to adopt a measure by reducing the size of the measurement unit and increasing the resistance change rate in the measurement unit. In order to prevent this, it is conceivable to form each flow channel other than the measurement section widely and deeply, but this is difficult in terms of fabrication and results in an increase in the required sample amount.

In FIG. 10B, in the conventional particle measuring apparatus, the relationship between the position (right and left direction on the paper surface) and the voltage value (proportional to the resistance value) in the particle measuring apparatus is indicated by a dotted line. Assuming that the applied voltage of the entire conventional particle measuring apparatus (the entire system) is _VIN , a voltage drop occurs in the upstream flow path 4a and the downstream flow path 4b, so that the voltage related to particle measurement (potential difference in the measurement unit) V1 ₂ ) becomes smaller. Therefore, since the voltage change in the measurement unit due to the presence or absence of particles becomes a value within the potential difference in the measurement unit, ΔV / V, which is a detection index of the measurement signal, is a value smaller than V1 ₂ / V _IN .

On the other hand, in the particle measuring device 15 (particle measuring method) according to the present embodiment, the conductors 3a and 3b having higher conductivity (lower electrical resistance) than the sample are arranged in the upstream channel 4a and the downstream channel 4b. doing. In the particle measuring apparatus 15 according to the present embodiment, the electrical resistance R2 between the electrodes 1a and 1b when there is no particle is expressed by the following equation (6):
R2 = R2 _6a + R2 _4a + R2 ₂ + R2 _4b + R2 _6b (6)
It becomes. Here, _{R2 6a} electrical resistance of the sample introduction portion 6a, _{R2 4a} electrical resistance of the upstream passage 4a, R2 ₂ is the electrical resistance of the measuring section 2, _{R2 4b} electrical resistance of the downstream flow path 4b, _{R2 6b} the sample It is an electrical resistance of the derivation | leading-out part 6b.

In the present embodiment, since the conductors 3a and 3b exist in the upstream flow path 4a and the downstream flow path 4b, the values of R2 _4a and R2 _4b are smaller than those without the conductors 3a and 3b. In particular, when metals are used as the conductors 3a and 3b, the values of R2 _4a and R2 _4b are substantially zero. Therefore, the equation (6) becomes the following equation (7), that is,
R2 = R2 _6a + R2 ₂ + R2 _6b (7)
To be rewritten. Since a large cross-sectional area sample inlet 6a and the sample derivation unit 6b is compared to the measurement section 2, small enough electrical resistance R2 _6a and R2 _6b is negligible compared to the resistance R2 ₂ of the measurement section 2 value (Substantially, R2≈R2 ₂ is satisfied).

When particles pass through the measurement unit 2, a part of the sample that is a conductor introduced into the measurement unit 2 is shielded by the particles that are substantially insulators, so that the electrical resistance of the measurement unit 2 increases. At this time, the electric resistance R2 ′ between the electrodes 1a and 1b is
R2 ′ = R2 _6a + R2 ₂ ′ + R2 _6b (8)
It becomes. Here, R2 ₂ ′ is the electrical resistance of the measurement unit 2 when particles are present.

Therefore, in order to detect the presence of particles as a measurement signal, the following equation (9), which is the resistance change rate,
ΔR2 / R2 = (R2'-R2 ) / R2 = (R2 2 '-R2 2) / R2 ... (9)
Is a detection index.

  Here, since the denominator R2 of the equation (9) is smaller than the denominator R1 when the conductors 3a and 3b are not provided (see the equation (5)) by the resistance of the upstream channel 4a and the downstream channel 4b, the resistance change rate Is a large value.

FIG. 10B shows the relationship between the position and the voltage value in the particle measuring device 15 with a solid line in the particle measuring device 15 according to the present embodiment.
If the applied voltage of the entire particle measuring device 15 (the entire system) is _VIN , there is substantially no voltage drop in the upstream flow path 4a and the downstream flow path 4b, so the voltage related to particle measurement (in the measurement unit 2) The potential difference V2 ₂ ) increases (V2 ₂ > V1 ₂ ). Therefore, since the voltage change in the measurement unit 2 due to the presence or absence of particles becomes a value within the potential difference in the measurement unit 2, ΔV / V (≦ V2 ₂ / V _IN ), which is a detection index of the measurement signal, is the upstream flow path. 4a and downstream flow path 4b are larger than the case where conductors 3a and 3b are not provided, respectively. Therefore, in the particle measuring apparatus 15 (particle measuring method using the apparatus) according to the present embodiment, the measurement of particles by the electric resistance method is performed with a very small amount of sample without causing an increase in the required sample amount, and the signal intensity is high. (S / N ratio) can be obtained.

  Next, it will be described that a high signal intensity can be obtained also in the particle measuring method in the sample using the particle measuring device 15 shown in FIGS. 4 (e) and (f).

In the configuration having the branch paths 24a and 24b and the conductors 3a and 3b shown in FIGS. 4E and 4F, the electrical resistance R3 between the electrodes 1a and 1b when there is no particle is expressed by the following equation (10). In addition,
R3 = R3 _6a + R3 _a + R3 ₂ + R3 _b + R3 _6b (10)
It becomes. Here, _{R3 6a} electrical resistance of the sample introduction portion 6a, R3 _a is the electrical resistance (combined resistance) consisting of the upstream passage 4a and the branch passage 24a, R3 ₂ is the electrical resistance of the measuring section 2, R3 _b downstream channel The electric resistance (combined resistance) consisting of 4b and the branch path 24b, R3 _6b is the electric resistance of the sample outlet 6b.

Combined resistance of R3 _a, since the upstream passage 4a and the branch passage 24a are connected in parallel, as shown in the following equation (11),
1 / R3 _a = 1 / R3 _4a + 1 / R3 _24a (11)
It becomes. Here, R3 _4a is the electrical resistance of the upstream flow path 4a, and R3 _24a is the electrical resistance of the branch path 24a. (11) By deforming the equation, combined resistance R3 _a, as shown in the following equation (12),
_{R3 a = (R3 4a · R3} 24a) / (R3 4a + R3 24a) ... (12)
It becomes. By arranging the conductor 3a having high conductivity (low electrical resistance) in the branch path 24a, R3 _4a >> R3 _24a , and R3 _a is substantially
_{R3 a = (R3 4a · R3} 24a) / (R3 4a) = R3 24a ... (13)
It becomes.

Therefore, the high resistance of the upstream flow path 4a in the micronized conventional particle measuring apparatus (when there is no branch path and no conductor) is low due to the arrangement of the branch path 24a and the conductor 3a of the present embodiment (the conductor 3a). When a metal is used as, it is substituted with substantially 0). The same applies to the downstream flow path 4b. Then, the cross-sectional area of the sample introduction portion 6a and the sample derivation section 6b is, upstream passage 4a, larger than the cross-sectional area of the downstream passage 4b and the measurement unit 2, substantially, the R3 ≒ R3 _2.

  Therefore, in order to detect the presence of particles as a measurement signal, ΔR3 / R3, which is the rate of change in resistance, becomes a detection index in the same manner as in equation (9), and is the same as described in equations (3) to (9) above. Since the denominator R3 is smaller by the resistance of the upstream flow path 4a and the downstream flow path 4b than the denominator R1 (see equation (5)) when the branch paths 24a, 24b and the conductors 3a, 3b are not provided, the resistance change rate Is a large value.

Similarly to the description using FIG. 10B described above, since there is substantially no voltage drop in the upstream flow path 4a and the downstream flow path 4b, the voltage (potential difference V3 in the measurement unit 2) involved in the measurement of particles. ₂ (V2 _{2 in} FIG. 10B) becomes larger (V3 ₂ > V1 ₂ ), so that the voltage change in the measurement unit 2 due to the presence or absence of particles becomes a value within the potential difference in the measurement unit 2, ΔV / V (≦ V3 ₂ / V _IN ), which is the detection index of the measurement signal, is larger than when the upstream flow path 4a and the downstream flow path 4b are not provided with the branch paths 24a and 24b and the conductors 3a and 3b, respectively.

  Therefore, in the particle measuring device 15 (particle measuring method using the device) shown in FIGS. 4 (e) and (f), an increase in the amount of necessary sample is not caused, and an extremely small sample is used to measure the particles by the electric resistance method. Measurements can be obtained with high signal strength (S / N ratio).

(Reason why a large resistance change rate can be obtained)
In the present embodiment, a large resistance change rate can be obtained regardless of the processing accuracy or material of the substrate 8a or 8b. The reason will be described with reference to FIG. In order to simplify the description, as shown in FIG. 11, it is assumed that the cross section of the measurement unit 2 is rectangular, and the particles passing through the measurement unit 2 are cubes with one side a. Similarly to FIG. 10, the particle measuring device 15 shown in FIG. 11 corresponds to the particle measuring device 15 shown in FIG.

As shown in FIG. 11, the measurement unit 2 has a width W, a depth H, and a length D. The electrical resistance R of the measurement unit 2 (aperture) when no particles are present is obtained from the equation (2):
R = ρ · D / (H · W) (14)
It is expressed. Here, ρ is the electrical resistivity of the sample.

For the sake of simplification, the electrical resistance R ′ when the particles of one side a are present in the measurement unit 2 is assumed to shield only the particle existence region.
R ′ = ρ · a / (H · W a ² ) + ρ · (D−a) / (H · W) (15)
It is expressed. Therefore, the resistance change ΔR is
ΔR = R′−R = ρ · a / (H · W−a ² ) −ρ · a / (H · W)
... (16)
It is expressed.

Also, the resistance change rate ΔR / R serving as the detection index of the measurement signal is
ΔR / R = (1 / D) · {(1 / (H · W−a ² )) − 1 / (H · W)} · a · H · W (17)
It is expressed.

  In order to increase the resistance change rate, as described above, the relationship between the cross-sectional area of the measuring unit 2 and the cross-sectional area of the particles is of course important, but the length D of the measuring unit is made as small as possible from the equation (17). It is important to form. However, in actual processing, when the length of the measurement unit 2 is reduced, the wall of the measurement unit 2 becomes thin and collapses, so that there is a problem that the length of the measurement unit 2 is practically limited. In particular, when a resin, for example, PDMS (polydimethylsiloxane) is used as the substrate material, the above problem becomes significant because of low mechanical strength.

  In the particle measuring apparatus 15 according to the present embodiment, the conductors 3a and 3b may be formed on a part of the measuring unit 2 (see FIG. 3A). In this case, not the length of the measuring unit 2 The distance between the conductors 3a and 3b corresponds to the length D in the equation (17). In actual processing, it is easy to form a short distance between the conductors 3a and 3b, such as formation of the conductors 3a and 3b using sputtering or lift-off. Therefore, in the particle measuring apparatus 15 according to the present embodiment, a large resistance change rate (measurement signal) can be obtained regardless of the processing accuracy and materials of the substrates 8a and 8b.

<Example>
Next, a specific example of the particle measuring device 15 described above will be described with reference to FIG. In addition, the Example shown below is an example to the last.

  In this example, first, an electrode substrate was manufactured by forming the electrode 1a, the electrode 1b, the conductor 3a, and the conductor 3b on a glass substrate by lift-off. Gold was used as the material for the electrodes 1a and 1b, and aluminum was used as the material for the conductors 3a and 3b. The electrodes 1a and 1b have a width (up and down direction of the paper surface of FIG. 1A) of 1 mm and a length (left and right direction of the paper surface of FIG. 1A) of 1 mm, and are formed at a distance from the conductors 3a and 3b. . The conductors 3a and 3b have a width of 100 μm and a length of 5 mm, and the distance between the conductors 3a and 3b (the left-right direction in FIG. 1A) is 100 μm.

  On the other hand, a flow path substrate was produced using PDMS resin in the form of molding into a convex mold. The upstream flow path 4a and the downstream flow path 4b have a width of 600 μm, a length of 5 mm, and a depth (in the direction perpendicular to the paper surface of FIG. 1B) of 20 μm. The measurement unit 2 was 20 μm wide, 100 μm long, and 20 μm deep. Further, by using a drill, a through hole (a sample introduction port 9a and a sample outlet 9b (see FIG. 12)) having a width of 5 mm, a length of 5 mm, and a depth of 5 mm corresponds to the sample introduction unit 6a and the sample extraction unit 6b. Provided.

  And the particle | grain measuring apparatus 15 was produced by bonding a flow path board | substrate and an electrode substrate so that the position of the upstream flow path 4a, the downstream flow path 4b, and the conductors 3a and 3b might each match.

  Polystyrene beads having a diameter of 10 μm (particles to be measured) dispersed in an electrolyte solution as a sample are introduced from the outside of the particle measuring device 15 into the sample introduction unit 6a using a tube, and the upstream flow path 4a, the measurement unit 2, The liquid was fed in the order of the downstream flow path 4b and the sample outlet 6b. Further, a tube is inserted into the sample lead-out unit 6b, and the sample is discharged from the particle measuring device 15 to the outside. After the sample is introduced into the particle measuring device 15, the sample introduction unit 6a and the sample lead-out unit 6b are partly connected. Also, the structure is open to the atmosphere (for example, the structure including the openings 10a and 10b (see FIG. 14)).

While observing the particle measuring device 15 under a microscope, a constant current was applied between the electrodes 1a and 1b, and the voltage value between the electrodes 1a and 1b was monitored. The measurement conditions in this example are as follows.
・ Constant current 30μA (Voltage is about 5V at this time)
・ Measurement temperature 20 ℃
Pump flow rate 1 uL / min (at this time, the particle velocity (when passing through the measuring unit 2) is 40 mm / s).

In addition, said measurement conditions are an example and measurement conditions (range) can be set as follows, for example.
Applied voltage: 1 to 100 V (± 50 V when alternating current), preferably 1 to 10 V (± 5 V when alternating current) when the sample is liquid. When the sample is a gas, it is 0.1 k to 100 kV, preferably 1 k to 10 kV. In the case of constant current, 0.1 μA to 10 mA, preferably 1 μA to 1 mA. (The voltage-current relationship is determined by the size of the particle measuring device 15 and the conductivity of the sample.)
Voltage frequency: 0.1 Hz to 100 MHz, preferably 1 Hz to 10 MHz.
Measurement temperature: 5 to 90 ° C, preferably 10 to 30 ° C.
Pump flow rate: 1 nL / min to 1 mL / min, preferably 1 nL / min to 10 uL / min.
Applied pressure (gauge pressure): 1 k to 1 MPa, preferably 1 k to 100 kPa. (In actual experiments, the flow control is mainly performed by a syringe pump. In this case, the pressure is not set.)
Particle speed: 1 μm / s to 10 m / s, preferably 10 μm / s to 1 m / s. (If it is assumed that the particles move at the same speed as the flow of the sample, the velocity of the particles is determined by the set flow rate or applied pressure and the size of the particle measuring device 15).
As a result of the measurement under the above measurement conditions, a voltage signal (measurement signal) caused by a change in resistance due to the particles was confirmed with a high S / N ratio in synchronization with the passage of the particles through the measurement unit 2. Further, bubbles generated by electrolysis in the electrodes 1a and 1b are discharged above the sample introduction part 6a and the sample outlet part 6b, and the bubbles block the surfaces of the upstream flow path 4a, the downstream flow path 4b, and the electrodes 1a and 1b. In addition, it was confirmed that the measurement of particles with high accuracy was performed without air bubbles passing through the measurement unit 2. The influence of air bubbles on particle measurement will be described in the second embodiment.

Specifically, the measurement results under the above measurement conditions are as follows.
-Voltage change due to particles 100 mV.
・ Noise level 1mV (There is room for improvement by shielding etc.).
・ S / N ratio is 100.

  Therefore, the particle measuring apparatus 15 according to the present embodiment can measure a high measurement signal intensity (S / N ratio) and a high measurement without causing an increase in the amount of the sample in the particle measurement in the sample using the electrical resistance method. It was shown that there is a great effect on the measurement with accuracy.

[Embodiment 2]
The following describes one embodiment of the present invention with reference to FIGS. In addition, about the member similar to Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

<Outline of the present embodiment>
In general, when a sample is a liquid, bubbles are generated in the electrode due to electrolysis of the sample with application of a voltage to the sample. Conventionally, in a system using a micro-channel, in order to increase the rate of change in resistance associated with the passage of blood cells through an aperture, measurement electrodes are formed near the aperture (that is, in the channel at both ends of the aperture). There was a need to do. However, in this case, the influence of bubbles due to electrolysis accompanying voltage application (the generated bubbles block the flow path, cover the surface of the electrode involved in the measurement, and miscounting occurs because the bubbles pass through the aperture and cause a resistance change) , Etc.) has caused a problem that the measurement accuracy is lowered.

  Note that it is conceivable to lower the applied voltage in order to reduce the influence of bubbles, but this leads to a decrease in the strength of the measurement signal. Further, as described in Patent Document 3, by setting the measurement electrode downstream of the aperture, it is possible to prevent passage of bubbles generated by electrolysis to the aperture. There has been a problem that the generated bubbles cover the flow path and / or the surface of the measurement electrode. Here, it is possible to reduce the influence of bubbles generated by flowing the sample at a high speed, but a high-performance pump is required for liquid feeding, and a high sampling rate is required for particle measurement (because the particle aperture passing time is short). ) Is required, and a complicated and expensive particle measuring device is required. Further, since it is necessary to flow at a high speed, there arises a problem that the sample is limited to one having a low viscosity.

  As described above, conventionally, when the particle measuring device (the flow path provided in the device) is micronized for the purpose of reducing the amount of the sample, there has been a problem that the measurement accuracy is lowered.

  In order to solve the above-described problem, the particle measuring apparatus according to the present embodiment includes at least two electrodes, a measurement unit, and at least one flow channel connected to the measurement unit and through which a sample flows. Yes. At least one of the electrodes is a region different from the measurement unit and the flow channel, and a streamline (main line of the flow of the sample formed when the sample flows through the measurement unit and the flow channel) It is arranged in a part of the specific area which is an area different from that shown in FIG.

  Thereby, since the electrode is arrange | positioned in a part of specific area | region, the bubble which generate | occur | produced in the electrode can suppress inflow on the flow line which a sample forms in a flow path and a measurement part. That is, it can suppress that the said bubble flows in into a measurement part with a sample. In addition, at least air bubble coating on the flow path can be suppressed. Therefore, highly accurate particle measurement can be performed.

  Moreover, the particle | grain measuring apparatus which concerns on this Embodiment is equipped with the sample introduction part containing the specific electrode which is any one electrode among electrodes in a part of the said specific area | region. Thereby, compared with the case where an electrode is arrange | positioned in a flow path like before, the inflow to the measurement part of the bubble which generate | occur | produced in the electrode can be suppressed.

<Specific Configuration of Particle Measuring Device 15a>
First, based on FIG. 12, a schematic configuration of the particle measuring device 15a according to the present embodiment and suppression of the influence of air bubbles exerted on the particle measurement caused by the configuration will be described. FIG. 12A is a top view showing an example of a schematic configuration of a particle measuring apparatus according to an embodiment of the present invention, and FIG. 12B is a cross-sectional view thereof.

  Similar to the first embodiment, the particle measuring device 15a includes electrodes 1a and 1b, a measuring unit 2, an upstream channel 4a, a downstream channel 4b, a sample introduction unit 6a, and a sample derivation unit 6b. These materials, shapes, sizes, connection relationships, and the like are as described in the first embodiment. However, the particle measuring device 15a is different from the particle measuring device 15 in that the conductors 3a and 3b are not provided. The overall structure of the particle measuring device 15a and the manufacturing method thereof are the same as those in the first embodiment except that the conductors 3a and 3b are included.

  In the present embodiment, each of the electrodes 1a and 1b for applying a voltage to the sample is disposed in the sample introduction part 6a and the sample lead-out part 6b having a larger cross-sectional area than the upstream flow path 4a and the downstream flow path 4b. . In other words, the depth of the sample introduction part 6a is longer than the depth of the upstream flow path 4a. For this reason, since the bubbles 11 generated in the electrode 1a can be kept inside the sample introduction part 6a, the bubbles 11 flow into the measurement part 2, and the upstream flow path 4a and the downstream flow path 4b. It is possible to reliably prevent the air bubbles 11 from covering the surface and the surfaces of the electrodes 1a and 1b. In addition, since the depth of the sample outlet 6b is longer than the depth of the downstream flow path 4b, the bubble 11 generated at the electrode 1b flows into the measuring unit 2 as well as at least downstream. It is possible to reliably prevent the bubbles 11 from covering the surface of the flow path 4b and the surface of the electrode 1b.

  Hereinafter, this phenomenon will be further described with reference to FIG. FIG. 12B is a schematic cross-sectional view of the particle measuring device 15a along the line A-A ′ shown in FIG.

  Conventionally, when a liquid or a polymer solution is used as a sample, there is a problem that bubbles are generated from the electrodes due to electrolysis due to voltage application necessary for detection of resistance change, and measurement accuracy is lowered.

  Specifically, in the conventional particle measurement, when the presence or absence of particles in the aperture (corresponding to the measuring unit 2 of the particle measuring device 15) is regarded as a change in electrical resistance, two electrodes are arranged so as to sandwich the aperture. A voltage (or current) is applied to these electrodes. With the application of this voltage (current), the water component in the sample mainly undergoes electrolysis, and bubbles (hydrogen and oxygen in the case of water) are generated at these electrodes. When the generated bubble (insulator) passes through the aperture, the electrical resistance of the aperture changes, which causes a false count in the measurement signal detection, resulting in a problem that the measurement accuracy is lowered. In addition, when these electrodes are formed in the micro flow path, measurement accuracy is improved due to the influence of air bubbles due to electrolysis accompanying voltage application (the generated bubbles block the flow path, cover the surface of the electrodes involved in measurement, etc.). There has been a problem in that the remarkably decreases.

  On the other hand, as shown in FIG. 12B, when measuring particles, for example, a sample containing particles is introduced from the sample introduction unit 6a, and the sample introduction unit 6a, the upstream channel 4a, the measurement unit 2, and the downstream channel 4b. The sample is fed in the order of the sample outlet 6b.

  When a voltage (current) is applied between the electrodes 1a and 1b for detection of electrical resistance, bubbles 11 accompanying electrolysis are generated from the surfaces of the electrodes 1a and 1b.

  Since the electrodes 1a and 1b are arranged not in a narrow space such as the upstream flow path 4a and the downstream flow path 4b but in a wide space in the sample introduction part 6a and the sample lead-out part 6b, the generated bubbles 11 are generated in the upstream flow path 4a and A situation where the downstream flow path 4b is blocked can be prevented. Further, since buoyancy acts on the generated bubbles 11, the bubbles 11 move upward (in the depth direction) above the sample introduction part 6a and the sample lead-out part 6b. For this reason, the measurement accuracy of particles is not lowered by covering the surfaces of the electrodes 1a and 1b and the upstream flow path 4a and the downstream flow path 4b.

  Therefore, in this embodiment, since the influence of the bubbles 11 accompanying the above electrolysis can be eliminated, even when a gas, a liquid, a polymer solution, or the like is used as a sample, highly accurate particle measurement is performed. It can be carried out.

  Further, as shown in FIG. 12 (b), in order to let the bubbles 11 moved above the sample derivation unit 6b escape to the outside of the particle measuring device 15a, the sample introduction unit 6a and the sample derivation unit 6b are respectively above the sample introduction unit 6b. The gas (for example, air) layer 12 is preferably formed after the sample is filled into the particle measuring device 15a accompanying the particle measurement or introduced by the sample flow. Alternatively, it is preferable that at least a part of each of the sample introduction part 6a and the sample lead-out part 6b is provided with openings 10a and 10b (for example, FIG. 14), and the openings 10a and 10b are directly or indirectly opened to the atmosphere. . These configurations will be described later.

  Thus, when the sample is a liquid, in the present embodiment, unlike the conventional particle measuring device, it is not necessary to flow the sample at a high speed in order to suppress the influence of the generated bubbles. For this reason, since it does not require a high sampling rate in the measurement of a highly functional pump or particle | grains, the particle | grain measuring apparatus 15a can be made into a simple structure, and can be manufactured at low cost. In the present embodiment, since it is not necessary to flow the sample at a high speed, a sample having a viscosity such as a polymer solution such as a gel can be used as the sample.

  When the sample is a gas, bubbles due to electrolysis are not generated, but it is necessary to apply a high voltage in order to measure a resistance change due to particles in the gas. In this case, if the distance between the measurement electrodes 1a and 1b is short, there is a possibility that leakage to other than the measurement unit 2 due to the high voltage, voltage instability, etc. may occur, and particle measurement accuracy may decrease. There is. In the present embodiment, the electrodes 1a and 1b are disposed in the sample introduction part 6a and the sample lead-out part 6b, respectively, and are provided so as to be separated via the upstream flow path 4a and the downstream flow path 4b. And the distance between 1b can be lengthened. For this reason, the freedom degree of the apparatus structure of the particle | grain measuring apparatus 15a goes up, and it becomes possible to measure a particle | grain with high measurement accuracy without a high voltage leak.

  In this way, when the flow path is micronized, bubbles generated inside the flow path are difficult to escape from the flow formed by the sample, so that the flow into the measurement unit becomes significant. In the particle measuring device 15a of the present embodiment, at least the electrode 1a (specific electrode) is arranged in a part of the sample introduction part 6a. That is, a sample introduction part 6a different from the upstream flow path 4a and the downstream flow path 4b (for example, a micro-flow path) is provided, and the sample introduction part 6a is provided with the electrode 1a. Unlike the measurement unit 2, the upstream channel 4a, and the downstream channel 4b, the particle measuring device 15a includes at least the electrode 1a in a part of a specific region that is different from the streamline formed by the sample. I can say that.

  For this reason, bubbles are generated inside the sample introduction part 6a, and at least a part of the bubbles can be kept inside the sample introduction part 6a. That is, it is difficult for the bubbles to enter the flow, the inflow to the measurement unit 2 that has occurred in the past can be suppressed, and the covering of the bubbles to the upstream flow path 4a and the downstream flow path 4b can be suppressed.

  As shown in FIG. 12, the sample introduction unit 6a includes a sample introduction port 9a through which a sample can be introduced into the sample introduction unit 6a, and the sample derivation unit 6b is provided outside the sample derivation unit 6b. A sample outlet 9b through which a sample can be derived is provided. Thereby, when the sample is liquid or gas, the sample introduced from the sample introduction port 9a flows to the measurement unit 2 via the sample introduction unit 6a and the upstream channel 4a, and then the downstream channel 4b and It is derived from the sample outlet 9b through the sample outlet 6b. In FIG. 12, an example of the mainstream of the sample is shown as a streamline.

  Further, the particle measuring device 15a shown in FIG. 12 includes a sample introduction port 9a and a sample outlet 9b. An example of a state in which the sample inlet 9a and the sample outlet 9b are provided is shown in FIG. FIG. 13 shows a case where the shape of the sample introduction port 9a and the sample outlet 9b is circular. However, the shape is not limited to this, and it is possible to introduce / lead the sample such as an ellipse or a rectangle. It suffices if it penetrates, for example, the upper surfaces of the sample introduction part 6a and the sample lead-out part 6b.

  For example, when a sample is introduced using a pump, the sample introduction port 9a preferably has a shape to which a tube for liquid feeding can be attached. Thus, it is preferable to change the shape of the sample inlet 9a and the sample outlet 9b depending on the mode of introduction / derivation.

  Further, when a tube or the like is connected to the sample introduction port 9a for feeding the liquid to the sample introduction port 9a using a pump, or when the sample is introduced by capillary force, a part of the sample introduction port 9a is an opening described later. It is also possible to function as the unit 10a.

  Furthermore, as shown in FIG. 12, the sample introduction port 9a is provided between the electrode 1a and a connection region where the sample introduction part 6a and the upstream flow path 4a are connected. That is, the electrode 1a is provided on the opposite side of the connection region with respect to the sample introduction port 9a (outside of the streamline when the direction of the streamline in the upstream flow path 4a is set inside) It is provided in a region other than the upper surface region of the intersecting sample introduction part 6a.

  In this case, the bubbles 11 generated from the electrode 1a rise in the vertical direction by buoyancy in the sample (liquid) convected by the sample introduction part 6a. Therefore, by arranging the electrode 1a outside the streamline, it is possible to prevent the bubbles 11 generated at the electrode 1a from flowing into the measurement unit 2 along the streamline. It is possible to prevent erroneous counting due to voltage application to the electrode and to measure particles with high accuracy.

  Moreover, it is preferable that the ratio of the sample amount in the sample introduction part 6a when the sample is introduced into the sample introduction part 6a with respect to the volume of the sample introduction part 6a is 1 / 50,000 or more and 0.9 or less.

  In this case, since the sample is filled at least near the lower surface of the sample introduction portion 6a (the bottom surface on which the electrode 1a is provided in FIG. 9), a voltage can be applied to the sample. On the other hand, since the ratio is not 1 (that is, the sample is not filled in the entire sample introduction part 6a), the gas layer 12 is formed in the sample introduction part 6a. For this reason, the bubbles 11 rising from the electrode 1a to the inside of the sample introduction part 6a can be absorbed by the gas layer 12, so that the bubbles 11 can be reliably prevented from flowing into the measurement part 2.

  In order to apply a voltage, the sample needs to be introduced into the sample introduction part 6a from at least the electrode 1a to the connection region with the upstream channel 4a (inlet region of the upstream channel 4a). is there. That is, the bottom surface of the sample introduction part 6a needs to be filled with the sample at the minimum. As described above, when the ratio is calculated from the ratio of the depth of the upstream flow path 4a (minimum of 1 μm) and the depth of the sample introduction part 6a (maximum of 50000 μm), the above ratio is preferably 1 / 50,000 or more.

  Note that the sample outlet 6b and the sample outlet 9b may have the same configuration as the sample inlet 6a and the sample inlet 9a, but the sample liquid is passed from the sample inlet 6a through the measuring section 2 to the sample outlet. In view of the fact that air bubbles generated at the electrode 1b in the sample lead-out part 6b do not pass through the measurement part 2 because they flow to 6b, the sample lead-out port 9b is not necessarily required.

<Another Example (Part 1) of Particle Measuring Device 15a>
Next, another example of the particle measuring device 15a will be described based on FIG. 14 and FIG. FIG. 14 is a top view and a cross-sectional view showing still another example of the schematic configuration of the particle measuring device 15a. A particle measuring device 15a shown in FIG. 14 includes openings 10a and 10b in addition to the sample inlet 9a and the sample outlet 9b.

  As shown in FIG. 14, each of the sample introduction part 6a and the sample lead-out part 6b includes openings 10a and 10b that open the bubbles 11 generated from the electrodes 1a and 1b to the atmosphere. This ensures that the bubbles 11 that have moved above the sample introduction part 6a and the sample lead-out part 6b move on the streamline due to convection (due to Joule heat, sample flow, etc.) and flow into the measurement part 2. Can be eliminated. Note that since the sample liquid flows from the sample introduction part 6a to the sample lead-out part 6b via the measurement part 2, the bubbles 11 generated at the electrode 1b in the sample lead-out part 6b do not pass through the measurement part 2. In consideration of this, the opening 10b is not necessarily a necessary configuration.

  Further, as described above, the bubbles 11 generated at the electrodes 1a and 1b move above the sample introduction part 6a and the sample lead-out part 6b, respectively. Therefore, the openings 10a and 10b are respectively on the vertical lines of the electrodes 1a and 1b (the sample introducing part 6a and the sample deriving part intersecting the vertical lines of the electrodes 1a and 1b) in the sample introducing part 6a and the sample leading part 6b, respectively. 6b is preferably disposed in the upper surface region of each of 6b. In this case, the bubbles 11 generated in each of the electrodes 1a and 1b can be surely released to the outside of the particle measuring device 15a.

  The electrode 1a is opposite to the connection region between the sample introduction part 6a and the upstream flow path 4a with respect to the sample introduction port 9a (outside the stream line when the direction of the stream line in the upstream flow path 4a is set to the inside. ). In addition, the electrode 1b is opposite to the connection region between the sample outlet 6b and the downstream channel 4b with respect to the sample outlet 9b (the flow when the direction opposite to the direction of the streamline in the downstream channel 4b is set to the inner side). Outside the line). For this reason, it is possible to prevent the bubbles 11 generated at the electrodes 1a and 1b from flowing into the measurement unit 2 along the streamline, and to more effectively eliminate the bubbles 11 from the sample introduction unit 6a and the sample lead-out unit 6b. Can do.

  FIG. 15 shows an example in which the sample introduction part 6a and the sample lead-out part 6b are provided with openings 10a and 10b, respectively. FIG. 15 shows a case where the shapes of the openings 10a and 10b are circular. However, the present invention is not limited to this, and the sample introduction unit 6a is capable of allowing bubbles to escape into the atmosphere, such as an ellipse or a rectangle. It only has to penetrate the upper surface of the sample outlet 6b.

  Also in the second embodiment, the shapes of the upstream flow path 4a and the downstream flow path 4b are not limited to the shapes shown in FIGS. 12 and 14, but may be the shapes shown in FIGS. 4 to 8, for example. .

<Modification>
Next, a modified example of the particle measuring device 15a will be described with reference to FIGS. 16 shows an example of a configuration in which the particle measuring device 15a shown in FIG. 12 includes the conductors 3a and 3b, and FIG. 17 shows an example of a configuration in which the particle measuring device 15a shown in FIG. 14 includes the conductors 3a and 3b. Show. In either case, as described above, the influence of bubbles in particle measurement is suppressed, and as described in the first embodiment, a strong measurement signal can be obtained by the conductors 3a and 3b. Measurement of fine particles.

  Further, when the sample is a gas, there is a possibility that the measurement accuracy of the particles is lowered as described above. In the present modification, the conductors 3a and 3b are provided so as to separate the electrodes 1a and 1b from the measurement unit 2, so that the distance between the electrodes 1a and 1b can be increased. For this reason, the freedom degree of the apparatus structure of the particle | grain measuring apparatus 15a goes up, and it becomes possible to measure a particle | grain with high measurement accuracy without a high voltage leak. The same can be said for the first and third embodiments.

[Embodiment 3]
The following describes one embodiment of the present invention with reference to FIGS. Note that members similar to those in the first or second embodiment are denoted by the same reference numerals and description thereof is omitted.

<Outline of the present embodiment>
As described in the second embodiment, conventionally, there has been a problem that the measurement accuracy is lowered due to the influence of bubbles generated in the electrodes.

  As described in the second embodiment, the particle measuring apparatus according to the present embodiment is a region in which at least one of the electrodes is different from the measurement unit and the flow path in order to solve the above problem. And it arrange | positions in a part of specific area | region which is an area | region different from the streamline used as the main line of the flow of the said sample formed when a sample flows through a measurement part and a flow path.

  Thereby, since the electrode is arrange | positioned in a part of specific area | region, the bubble which generate | occur | produced in the electrode can suppress inflow on the flow line which a sample forms in a flow path and a measurement part. That is, it is possible to suppress the bubbles from flowing into the measurement unit together with the sample as compared with the case where electrodes are arranged in the flow path as in the past. In addition, at least air bubble coating on the flow path can be suppressed. Therefore, highly accurate particle measurement can be performed.

<Specific Configuration of Particle Measuring Device 15b>
Next, based on FIG. 18, a schematic configuration of the particle measuring device 15 b according to the present embodiment and suppression of influence on particle measurement exerted by bubbles caused by the configuration will be described. 18A is a top view illustrating an example of a schematic configuration of the particle measuring apparatus according to the embodiment of the present invention, and FIG. 18B is a schematic cross-sectional view taken along the line AA ′ in FIG. c) is a schematic cross-sectional view along the line BB ′.

  Similar to the first and second embodiments, the particle measuring device 15b includes electrodes 1a and 1b, a measuring unit 2, a sample introducing unit 6a, and a sample deriving unit 6b, and these materials, shapes, and sizes. These are as described in the first embodiment. The particle measuring device 15b further includes an upstream channel 21a, a downstream channel 21b, conduction channels 22a and 22b, and reservoirs 23a and 23b. The upstream channel 21a and the downstream channel 21b have the same functions as those described in the first embodiment.

  As shown in FIG. 18 (a), one end of the upstream flow path 21a is connected to the measurement section 2, and the other end is connected to the sample introduction section 6a. Moreover, one end of the downstream flow path 21b is connected to the measurement part 2, and the other end is connected to the sample derivation | leading-out part 6b.

  Further, the conduction paths 22a and 22b electrically connect the sample to each of the electrodes 1a and 1b electrically connected to the upstream flow path 21a and the downstream flow path 21b (branched from these flow paths). Is for. That is, the conduction paths 22a and 22b are provided in the specific region described above.

  In addition, one end of the conduction path 22a is connected to a connection region 251 other than the end of the upstream flow path 21a (the end connected to the measurement unit 2 and the sample introduction unit 6a). Similarly, one end of the conduction path 22b is connected to a connection region 252 other than the end of the downstream flow path 21b (the end connected to the measurement unit 2 and the sample outlet 6b).

  The conducting paths 22a and 22b are filled with an electrolyte for electrically conducting the sample and the electrodes 1a and 1b. Thereby, the voltage application to the sample can be reliably performed via the conduction paths 22a and 22b. Examples of the electrolyte include a liquid electrolyte (that is, an electrolytic solution) and a non-fluidic electrolyte. Examples of the electrolytic solution include a sodium chloride solution and a potassium chloride solution.

  Examples of the non-fluidic electrolyte include substances having two properties of a solid electrolyte and a gel-like substance containing a liquid electric field substance. Examples of the solid electrolyte include chloride ion conductive solid electrolyte, β alumina, and stabilized zirconia. Examples of the gel-like substance containing a liquid electrolyte include salt bridge (agarose containing potassium chloride, ammonium nitrate or lithium acetate), polyvinyl chloride containing a liquid electrolyte such as potassium chloride, or polyacrylamide.

  When a non-fluidic electrolyte is used as the electrolyte of the conduction paths 22a and 22b (when the fluidity of the contents of the conduction paths 22a and 22b is low), the sample remains in the conduction path even when the measurement is performed while the sample is flowing. It flows through the upstream flow path 21a and the downstream flow path 21b without flowing into 22a and 22b (see, for example, FIGS. 18B and 18C). In other words, even if bubbles 11 are generated due to electrolysis in the electrodes 1a and 1b provided in the reservoirs 23a and 23b, the bubbles 11 flow into the upstream flow path 21a, the downstream flow path 21b, and the measurement unit 2. There is no. For this reason, the bubbles 11 flow through the measuring unit 2, and erroneous counting due to voltage application to the bubbles 11 in the measuring unit 2 can be prevented, and highly accurate particle measurement is possible. Further, since the sample does not flow into the conduction paths 22a and 22b, it is possible to measure particles without increasing the amount of the sample. The non-fluid electrolyte does not necessarily need to be formed in the entire region of the conduction paths 22a and 22b, and may be formed at least partially. In this case, for example, a liquid electrolyte (described later) may be formed in the region other than where the non-flowable electrolyte of the conduction path is formed.

  On the other hand, when a liquid electrolyte is used as the electrolyte of the conduction paths 22a and 22b (when the fluidity of the contents of the conduction paths 22a and 22b is high), the connection area between the conduction paths 22a and 22b and the reservoirs 23a and 23b is used. For example, a lid or a sealing material may be provided. In this case, since the reservoirs 23a and 23b can be sealed and physically sealed, the bubbles 11 generated inside the reservoirs 23a and 23b can be prevented from flowing into the conduction paths 22a and 22b.

  Since the conduction paths 22a and 22b and the reservoirs 23a and 23b need to be electrically connected, the lid and the sealing material are preferably made of an electrically conductive material. Further, the lid and the sealing material may be provided in at least a part of the conduction paths 22a and 22b instead of the connection region. It is also possible to fill the conductive paths 22a and 22b with a liquid electrolyte and seal the connection region, for example, with a gel substance.

  Alternatively, the top surfaces of the reservoirs 23a and 23b may be physically sealed with a lid and a sealing material after filling with a liquid electrolyte. In this case, the reservoirs 23a and 23b have a damming structure that prevents the sample from flowing into the conduction paths 22a and 22b with respect to the upstream flow path 21a and the downstream flow path 21b through which the sample flows.

  For example, when there are openings in the reservoirs 23a and 23b, the openings are open to the atmosphere, so that the electrolyte introduced into the conduction paths 22a and 22b and the reservoirs 23a and 23b flows into the sample (for flowing the sample). May be moved to the opening under the influence of the applied pressure. As a result, the sample may flow into the reservoirs 23a and 23b.

  In the case of the damming structure described above, the sample does not flow into the conduction path 22a connected to the reservoir 23a and the conduction path 22b connected to the reservoir 23b, and the sample flows through the upstream channel 21a, the measurement unit 2, and the downstream channel 21b. It flows in order. That is, the electrolyte introduced into the conduction paths 22a and 22b and the reservoirs 23a and 23b is substantially stationary.

  Therefore, it is possible to prevent the bubbles 11 generated in the reservoirs 23a and 23b from flowing into the conduction paths 22a and 22b. The lid and the sealing material only need to have a sealing property with respect to the substrate on which the reservoirs 23a and 23b are formed, and a wide range of materials can be selected.

  Further, when a non-fluidic electrolyte is used as the electrolyte of the conduction paths 22a and 22b, the sample can be prevented from flowing into the conduction paths 22a and 22b (or the inflow of the bubbles 11) as described above. Even in this case, the physical sealing as described above may be performed in order to prevent these inflows more reliably.

  As described above, at least a part of the conduction paths 22a and 22b or the other ends of the conduction paths 22a and 22b (connection region with the reservoirs 23a and 23b) is non-suppressing the flow of the sample into the reservoirs 23a and 23b. Inflow suppressing members such as a fluid electrolyte, a lid, and a sealing material are provided. Alternatively, the upper surfaces of the reservoirs 23a and 23b are provided with inflow suppressing members such as a lid and a sealing material that suppress the inflow of the sample into the reservoirs 23a and 23b. Accordingly, since the sample can be prevented from flowing into the reservoirs 23a and 23b, it is possible to prevent the bubbles 11 generated inside the reservoirs 23a and 23b from flowing into the upstream channel 21a and the downstream channel 21b together with the sample. it can.

  The reservoirs 23a and 23b are provided in the specific region described above, hold an electrolyte that electrically conducts the electrodes 1a and 1b and the sample, and are connected to the other ends of the conducting paths 22a and 22b, respectively. Further, electrodes 1a and 1b are disposed on at least a part of the reservoirs 23a and 23b, respectively. With this arrangement, electrodes 1a and 1b are connected to conduction paths 22a and 22b, respectively.

  According to this configuration, even when the electrodes 1a and 1b are respectively disposed in the reservoirs 23a and 23b, a voltage can be applied to the sample existing in the measurement unit 2 via the conduction paths 22a and 22b. In addition, since the electrodes 1a and 1b are disposed in the reservoirs 23a and 23b, at least a part of the bubbles 11 generated in the electrodes 1a and 1b can be retained inside the reservoirs 23a and 23b, and the conductive paths 22a and 22b are connected. Inflow of the bubbles 11 can be suppressed.

  The reservoirs 23a and 23b are preferably filled with the liquid electrolyte described above for the purpose of allowing the bubbles 11 generated from the electrodes 1a and 1b to escape upward. Regardless of which electrolyte is used, the voltage applied to the electrodes 1a and 1b is applied to the sample in the upstream flow path 21a and the downstream flow path 21b via the electrolyte or electrolyte in the reservoirs 23a and 23b. This makes it possible to perform resistance measurement associated with particle passage in the measurement unit 2.

  Moreover, the width | variety of the conduction paths 22a and 22b is 1-5000 micrometers, Preferably it is 1-1000 micrometers, The depth is 1-1000 micrometers, Preferably it is 1-100 micrometers. The reservoirs 23a and 23b have a width of 1 to 50000 μm, a depth of 1 to 50000 μm, and a length of 1 to 50000 μm.

  In the particle measuring device 15b, the sample is introduced from the sample introduction unit 6a, passes through the upstream channel 21a, the measurement unit 2, and the downstream channel 21b in this order, and is discharged to the outside from the sample derivation unit 6b. That is, in the particle measuring device 15b, the sample is introduced into the upstream flow path 21a and the downstream flow path 21b, and is supplied to the conduction paths 22a and 22b connected to the upstream flow path 21a and the downstream flow path 21b. Therefore, the upstream flow path 21a, the measurement unit 2, and the downstream flow path 21b are the main flow paths of the sample.

<Another example of arrangement of electrodes 1a and 1b>
In the above description, the reservoirs 23a and 23b are provided in a part of the specific region described above, and the electrodes 1a and 1b are provided in the reservoirs 23a and 23b, respectively, but the configuration is not limited thereto. For example, the electrodes 1a and 1b may be provided in the conduction paths 22a and 22b provided in a part of the specific region, respectively. That is, the electrodes 1a and 1b may be disposed on at least a part of the conduction paths 22a and 22b, respectively. In this case, the reservoirs 23a and 23b are not necessarily required.

  Even in this configuration, a voltage can be applied to the sample existing in the measurement unit 2, and at least a part of the bubbles 11 generated in the electrodes 1a and 1b can be kept inside the conduction paths 22a and 22b. For this reason, inflow of the bubble 11 to the upstream flow path 4a or the downstream flow path 4b can be suppressed.

<Pressurization in the reservoirs 23a and 23b>
In the particle measuring device 15b, the electrolyte solution (electrolyte) filled in the reservoirs 23a and 23b is pressurized in the direction connected to the conduction paths 22a and 22b.

  The magnitude of the pressurization is preferably a magnitude that prevents at least the sample from flowing into the reservoirs 23a and 23b. This is achieved by setting the pressure due to the pressurization higher than the pressure due to the flow of the sample in the connection region between the reservoir 23a and the conduction path 22a or the connection region between the reservoir 23b and the conduction path 22b. Note that the pressure due to the flow of the sample is determined by the applied pressure for flowing the sample and the pressure loss accompanying the flow of the sample (depending on the device structure).

Here, when the flow of the sample is a laminar flow (for example, a flow in a microchannel), the pressure loss ΔP is expressed by the following equation (18) (Hagen-Poiseuille equation), that is,
ΔP = 32 · μ · L · v / D ² (18)
Can be estimated. Here, μ is the viscosity of the sample, L is the channel length, v is the velocity of the sample flow, and D is the diameter (width and / or depth) of the channel. The magnitude of the pressurization is appropriately set according to the structure of the particle measuring apparatus, the applied pressure, and the properties of the sample used for measurement so as to be larger than the pressure due to the sample flow.

  Furthermore, the magnitude of the pressurization is preferably a magnitude that prevents the sample from flowing into the conduction path 22a or the conduction path 22b. This is because the pressure due to the pressurization is set larger than the pressure due to the flow of the sample in the connection region 251 between the conduction path 22a and the upstream flow path 21a or the connection area 252 between the conduction path 22b and the downstream flow path 21b. Is achieved.

  By setting the size of these pressurizations, it is possible to prevent the sample from flowing into the reservoirs 23a and 23b, or into the conduction path 22a or the conduction path 22b, and without increasing the amount of the sample. Can be measured. Further, since the bubbles 11 generated from the electrodes 1a and 1b can escape above the reservoirs 23a and 23b by buoyancy, the bubbles 11 generated inside the reservoirs 23a and 23b together with the sample flow into the upstream flow path 21a and the downstream flow. It can prevent flowing into the path 21b.

  Furthermore, the pressure due to the pressurization and the pressure due to the flow of the sample are either (1) a connection area between the reservoir 23a and the conduction path 22a, or a connection area between the reservoir 23b and the conduction path 22b, or (2) a conduction path. It is preferable that the connection region 251 between the 22a and the upstream flow channel 21a or the connection region 252 between the conduction channel 22b and the downstream flow channel 21b is set to be substantially equal. When the pressure due to the pressurization and the pressure due to the flow of the sample are substantially equal, the electrolyte introduced into the conduction paths 22a and 22b and the reservoirs 23a and 23b is substantially stationary. Therefore, it is possible to reliably prevent the bubbles 11 generated in the reservoirs 23a and 23b from flowing into the conduction paths 22a and 22b.

  Examples of the pressurizing means include gravity (water head pressure) or capillary force acting on the electrolytes held in the reservoirs 23a and 23b or the conduction paths 22a and 22b, or a pump (pressurizing device). It is done.

When gravity is used as the means for pressurization, the pressure due to gravity (water head pressure) ΔP _HD is expressed by the following equation (19), that is,
ΔP _HD = ρ · g · h (19)
Can be estimated. Here, ρ is the density of the electrolyte, g is the gravitational acceleration, and h is the depth of the reservoirs 23a and 23b. In the particle measuring device 15b, it is preferable that the depth of the reservoirs 23a and 23b is longer than the depth of the conduction paths 22a and 22b. In this configuration, when the depth of the electrolyte held in the reservoirs 23a and 23b (the height of the liquid surface) is longer than the depth of the conduction paths 22a and 22b, gravity (water head pressure) is effectively applied to the electrolyte. The electrolytic solution can be reliably pressurized to the conductive paths 22a and 22b side by the action of gravity.

  In the present embodiment, the connection region between the conduction path 22a and the reservoir 23a and the connection region between the conduction path 22b and the reservoir 23b are in contact with the bottom surfaces of these members. However, the present invention is not limited to this, and it is only necessary that the conduction path 22a and the reservoir 23a are connected and the conduction path 22b and the reservoir 23b are connected so that pressurization can be performed by the action of gravity. In other words, the conduction paths 22a and 22b are connected to the side surfaces of the reservoirs 23a and 23b, respectively, and the side surfaces only need to be connected at least to positions that are not in contact with the upper surfaces of the reservoirs 23a and 23b.

When a capillary force is used as the pressurizing means, the pressure (Laplace pressure) ΔP _LP by the capillary force is expressed by the following equation (20) (Young-Laplace equation), that is,
ΔP _LP = −2 · γ · cos θ / R (20)
Can be estimated. Here, γ is the surface tension of the electrolyte, θ is the contact angle of the electrolyte, R is the radius of the reservoirs 23a and 23b (the radius of the surface perpendicular to the depth direction) (the reservoirs 23a and 23b in the conduction paths 22a and 22b) And the radius of the connection area cross section. In the particle measuring device 15b, the reservoirs 23a and 23b are preferably made of a hydrophobic material. In particular, it is preferable that the electrolyte solution filled in the reservoirs 23a and 23b is highly hydrophobic (the contact angle of the electrolyte solution is 90 degrees or more). In this case, a capillary force can be effectively applied to the electrolytic solution, and the electrolytic solution can be reliably pressurized to the conduction paths 22a and 22b by the action of the capillary force.

  Further, when a pump is used as the pressurizing means, the electrolyte solution is surely added to the conduction paths 22a and 22b without considering the shape of the reservoirs 23a and 23b and whether or not the material is hydrophobic. I can press. As the pump, for example, a syringe pump, a peristaltic pump, a pressure controller using air pressure, and the like are preferably used.

  When any of the above-described pressurizing means is used, the bubbles 11 generated inside the reservoirs 23a and 23b can be set together with the sample in the upstream flow path 21a and the downstream flow path by appropriately setting the above-described pressure level. It can prevent flowing into 21b.

  With the above configuration, the electrode 1a and the upstream flow path 21a are arranged via the conduction path 22a, and the electrode 1b and the downstream flow path 21b are arranged via the conduction path 22b. It can suppress that the bubble 11 which flowed into the measurement part 2 with the sample which flows through each flow path. In addition, the coating of the bubbles 11 on the surfaces of the upstream channel 21a and the downstream channel 21b and the surfaces of the electrodes 1a and 1b can be suppressed.

<Various configurations of the particle measuring apparatus 15b>
Next, various configurations of the particle measuring device 15b will be described with reference to FIG. 19A to 19C are top views showing other examples of the schematic configuration of the particle measuring device 15b.

  In FIG. 19A, the conduction path 22a is connected to the upstream flow path 21a via the connection region 251, and the electrode 1a is disposed in the reservoir 23a connected to the conduction path 22a, while the downstream flow path 4b Is not connected to the conduction path 22b. In this case, the electrode 1b is disposed inside the sample outlet 6b. That is, the particle measuring device 15b only needs to include at least one conduction path. Even with this configuration, it is possible to prevent the sample from flowing into the reservoir 23a and the bubbles 11 generated at the electrode 1a from flowing into the upstream flow path 21a. Since the sample flows from the upstream channel 21a to the downstream channel 21b, the inflow of bubbles to the measuring unit 2 can be sufficiently prevented even with the configuration in which the electrode 1a is arranged in the reservoir 23a on the sample introduction unit 6a side.

  Further, as shown in FIG. 18, the conduction paths 22a and 22b and the reservoirs 23a and 23b are not necessarily arranged on one side with respect to the upstream flow path 21a and the downstream flow path 21b. For example, FIG. As shown in FIG. 6, the upstream flow path 21a and the downstream flow path 21b may be arranged on the opposite side with the length direction as an axis. Further, the upstream flow path 21a and the downstream flow path 21b do not have to be linear, and in FIG. 19C, a part of the downstream flow path 21b is bent at a substantially right angle (FIG. 4). (See (d)). Even with such a configuration, the same effect as the configuration of FIG. 18 can be obtained.

  Also in the third embodiment, the shapes of the upstream flow path 21a and the downstream flow path 21b are not limited to the shapes shown in FIGS. 18 and 19, but may be the shapes shown in FIGS. 4 to 8, for example. .

<Modification>
Next, a modified example of the particle measuring device 15b will be described with reference to FIG. 20A shows an example of a configuration in which the particle measuring device 15b shown in FIG. 18 includes conductors 3a and 3b. FIGS. 20B to 20D show the particle measuring device 15b shown in FIG. An example of the structure provided with 3a and 3b is shown. In FIG. 20, it arrange | positions at the upstream flow path 21a, the downstream flow path 21b, the conduction path 22a, and / or the conduction path 22b with which it was equipped between the electrodes 1a and 1b.

  In either case, as described above, the influence of bubbles in particle measurement is suppressed, and as described in the first embodiment, a strong measurement signal can be obtained by the conductors 3a and 3b. Measurement of fine particles.

  20 (a) to 20 (d), the conductors 3a and 3b are formed in the entire regions of the conduction paths 22a and 22b, respectively. A configuration may also be adopted in which parts of 23a and 23b are provided so as to be separated from the electrodes 1a and 1b.

[Another expression of the present invention]
The present invention can also be expressed as follows.

  The particle measuring apparatus of the present invention is a particle measuring apparatus that measures the measurement of particles in a sample by impedance or electric resistance, wherein the particle measuring apparatus includes at least two electrodes for applying a voltage to the sample, The measurement unit is located between at least two electrodes and at least one conductor located between the at least one electrode and the measurement unit, and the two electrodes and the conductor are not connected.

  Further, the particle measuring device further includes at least one flow channel for measuring by flowing a sample, the flow channel and the measurement unit are connected, and the conductor is provided in at least a part of the flow channel. It is preferable that

  Further, it is preferable that the conductor is provided in at least two places of the flow path, and the two conductors are not connected in the flow path but are connected in a region outside the flow path.

  Further, there are at least two flow paths, and the at least two flow paths are an upstream flow path positioned on the upstream side of the measurement unit and a downstream flow path positioned on the downstream side of the measurement unit, and the conductor It is preferable that at least a part of the upstream flow path and / or the conductor is provided in at least a part of the downstream flow path.

  Further, it is preferable that there are at least two conductors, which are provided in at least a part of the upstream flow path and at least a part of the downstream flow path, and the at least two conductors are not connected to each other.

  One of the at least two conductors is provided on the upper surface and / or the lower surface of the upstream flow path, and the other of the at least two conductors is provided on the upper surface and / or the lower surface of the downstream flow path. Is preferred.

  Moreover, it is preferable that the linear shortest distance between the conductors of the conductor provided in at least a part of the upstream flow path and the conductor provided in at least a part of the downstream flow path is 0.1 to 1000 μm.

  Moreover, it is preferable that the said conductor is selected from the group which consists of a metal, carbon, a conductive polymer, and a non-fluid electrolyte.

  Further, the particle measuring device further includes a sample introduction unit for introducing a sample and / or a sample derivation unit for deriving a sample, and the sample introduction unit and / or the sample derivation unit includes the flow path, It is preferable that the flow paths are connected in a region different from a connection region with the measurement unit.

  One of at least two electrodes for applying a voltage to the sample is disposed on at least a part of the sample introduction part, and / or the other of the electrodes is at least one of the sample lead-out parts. It is preferable to arrange in the part.

  Further, it is preferable that the sample introduction part and / or the sample lead-out part includes an opening in a region different from a connection region with the flow path, and the opening is directly or indirectly opened to the atmosphere.

  Moreover, it is preferable that the said particle | grain measuring apparatus is further provided with a voltage application means, and the said voltage application means is connected to the at least 2 electrode for applying a voltage to the said sample.

  The particle measurement method of the present invention also includes a step of placing a sample in a measurement unit, a step of applying a voltage from at least two electrodes to the sample, and detecting the impedance or electrical resistance of the sample in the measurement unit. And applying the voltage by placing a conductor between the at least one electrode and the measurement unit.

  Moreover, it is preferable that the process of arrange | positioning the said sample in a measurement part is performed by the process of flowing a sample with respect to a measurement part.

  Moreover, it is preferable that the said particle | grain measuring method further includes the process of introduce | transducing the said sample from a sample introduction part, and the process derived | led-out from a sample derivation | leading-out part.

  The sample is preferably a liquid sample.

  Further, in the step of introducing the liquid sample into the sample introduction unit and / or deriving from the sample deriving unit, a gas layer exists in the sample introduction unit and / or the sample deriving unit, or / or at least It is preferable that it is partially or indirectly opened to the atmosphere.

  Moreover, it is preferable that the said conductor is selected from the group which consists of a metal, carbon, a conductive polymer, and a non-fluid electrolyte.

  Moreover, it is preferable that the flow path has a branched flow path structure that branches on one of the two electrodes and rejoins the flow path on the measurement unit side.

  Furthermore, the particle measuring apparatus of the present invention includes at least two electrodes, a measurement unit, at least one flow path, and a sample introduction unit, and one of the two electrodes is provided on the sample introduction unit. The first electrode is disposed at least partially.

  Moreover, it is preferable that the depth of the sample introduction part is deeper than the depth of the flow path.

  Moreover, it is preferable that the said sample introduction part is provided with the opening part which open | releases the bubble which generate | occur | produced from the said 1st electrode in air | atmosphere.

  Moreover, it is preferable to provide a voltage applying means connected to the two electrodes.

  Furthermore, the particle measuring apparatus of the present invention includes at least two electrodes, a measuring unit, and at least one sample channel through which the sample flows, the sample channel being connected to the measuring unit, There is provided at least one conduction channel for branching from the use channel and electrically connected to the sample, which is connected to one of the two electrodes.

  Moreover, it is preferable that at least a part of the conduction channel is filled with a non-flowing electrolyte for electrical conduction with the sample.

  The particle measuring apparatus includes at least one reservoir for holding an electrolyte for applying a voltage to the sample, and the conduction channel is a region different from a connection region with the sample channel. Thus, it is preferable that one of the two electrodes is connected to the reservoir, and is arranged as a first electrode on at least a part of the reservoir.

  Further, it is preferable that the reservoir is sealed in a region other than a connection region with the conduction channel.

  Further, it is preferable that the particle measuring apparatus includes a pressurizing unit for pressurizing the electrolyte held in the reservoir in a direction of a connection region between the reservoir and the conduction channel.

  The pressurizing means is preferably selected from the group consisting of gravity, capillary force, and pump.

  Moreover, it is preferable that the depth of the reservoir is deeper than the depth of the conduction channel.

  Moreover, it is preferable that the reservoir has a hydrophobic property with respect to the electrolyte introduced into the reservoir.

  Moreover, it is preferable that the particle measuring apparatus further includes a sample introduction part for introducing the sample into the apparatus, and the sample introduction part and the sample flow path are connected.

  Moreover, it is preferable to provide a voltage applying means connected to the two electrodes.

  Furthermore, the particle measuring apparatus of the present invention includes at least two electrodes, a measurement unit, at least one flow path, and a sample introduction unit, and any one of the two electrodes is any of the electrodes. The one electrode is provided in a region different from the streamline formed by the sample flowing through the flow path.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The particle measuring apparatus according to the present invention is a method for controlling the accuracy of manufacturing processes in the fields of electronics, mechatronics, etc. (for example, inspection for contamination), particle management in samples such as pharmaceutical manufacturing in the field of biotechnology, and It can be suitably used for measuring blood cells in blood in the medical field.

1a Electrode (specific electrode)
1b Electrode 2 Measuring part 3a, 3b Conductor 4a, 21a Upstream flow path (flow path)
4b, 21b Downstream channel (channel)
5 Conductor 6a Sample introduction part (specific area)
6b Sample lead-out part (specific area)
7 Connector 8a, 8b Substrate 9a Sample inlet 9b Sample outlet 10a Opening 10b Opening 11 Bubble 12 Gas layer 15, 15a, 15b Particle measuring device 22a, 22b Conduction path (specific region)
23a, 23b Reservoir (specific area)
24a, 24b Branch 241 First branch point 242 Second branch point 251, 252 Connection area

Claims (4)

A particle measuring apparatus capable of measuring particles contained in the sample by applying a voltage to the sample,
At least two electrodes for applying a voltage to the sample;
A measurement unit for measuring particles contained in the sample by detecting electrical resistance or impedance when a voltage is applied to the sample;
A sample introduction unit for introducing the sample into the apparatus;
And at least one flow path through which the sample flows, connected to the measurement unit and the sample introduction unit,
The sample introduction part includes any one of the electrodes,
When the electrode included in the sample introduction part is a specific electrode,
The sample introduction unit includes a sample introduction port capable of introducing the sample into the sample introduction unit,
The sample introduction port is provided between the specific electrode and a connection region where the sample introduction unit and the flow path are connected,
When the distance in the vertical direction toward the top of the flow channel facing the bottom with respect to the bottom of the flow channel is the depth of the sample introduction part and the flow channel,
The depth of the sample introduction part is longer than the depth of the flow path,
The specific electrode is disposed on a bottom surface of the sample introduction part, and the connection region is provided at a lower part of the sample introduction part ,
The particle measuring apparatus according to claim 1, wherein an opening for opening bubbles generated from the specific electrode to the atmosphere is provided on an upper surface of the sample introduction unit .   The ratio of the sample amount in the sample introduction part when the sample is introduced into the sample introduction part with respect to the volume of the sample introduction part is 1 / 50,000 or more and 0.9 or less. 2. The particle measuring apparatus according to 1. The opening, particle measuring apparatus according to claim 1 or 2, characterized in that it is arranged on the vertical line of the particular electrode. Particle measuring apparatus according to any one of claims 1 to 3, characterized in that it comprises a voltage application means connected to said electrode.

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