JP4567540B2 - Cell count device and cell count cartridge - Google Patents

Description

  The present invention relates to a cell number measuring device for measuring the number of cells in a liquid to be measured which is composed of an electrolyte containing cells, and a cartridge used in the cell number measuring device.

As shown in Patent Document 1, a conventional cell counting device called a Coulter counter (Cooler counter) stores a liquid to be measured made of an electrolyte containing cells in a liquid container provided inside the measuring device. By providing a fine aperture on the flow path that draws out the liquid to be measured from the liquid storage part, approximately one cell passes, and by measuring the impedance change when the cell passes through the aperture, the cell passes Each time the liquid to be measured changes, it is washed and repeatedly used.
JP 2004-257768 A

  However, as described above, this type of cell number measuring apparatus needs to be cleaned each time it is used, and requires considerable effort. In particular, when a body fluid such as blood is a liquid to be measured, since it is necessary to pay close attention during cleaning to prevent bacterial and virus infection, this work is a heavy burden.

  In addition, the aperture needs a diameter of one cell as described above, and a hole is made in a relatively hard plate material such as sapphire by electric discharge machining or the like so that the diameter does not change after being repeatedly used. Therefore, there is a problem that it is very expensive.

  An electrode can also be cited as a factor for increasing the price. That is, the electrode provided in the liquid to be measured for measuring the impedance change is made of an expensive material such as platinum having low reactivity and high corrosion resistance in order to withstand repeated use and enable precise measurement. This is because it must be used.

  Furthermore, since the liquid to be measured is introduced into the flow path formed inside the measuring device, the sealing property for connecting each component inside the measuring device is prevented so that the liquid to be measured does not leak from the flow path and enter the inside of the device. There is also a need to increase.

  For this reason, in the conventional cell counting device, the man-hours and costs required for maintenance after measurement are increased, and the internal configuration of the electrode and other components and the measuring device is resistant to corrosion and has high sealing performance. Is required.

  The present invention has been made in view of the above-described problems, and allows the number of cells contained in a liquid to be measured to be measured easily and at low cost, and the inside of the apparatus has corrosion resistance and high sealing performance. Providing a low-cost cell number measuring apparatus and the like that are not required is the main desired issue.

  That is, the cell number measuring apparatus according to the present invention includes a pair of channels in which a liquid to be measured including cells flows, an aperture provided on the channel, and a liquid contact portion disposed at a position sandwiching the aperture. An electrode, and counting the number of cells based on an impedance change between the electrodes due to the passage of cells through the aperture unit, a measurement unit main body for performing arithmetic processing such as cell number counting, the flow path and the aperture And a cartridge that is exposed to the outside of the flow path as a signal extraction portion, and is connected to the measurement unit main body at the signal extraction portion in a detachable manner. It is provided.

  Further, the cartridge according to the present invention includes a flow path through which a liquid to be measured including cells flows, an aperture section provided on the flow path, and a pair of electrodes each having a liquid contact section disposed at a position sandwiching the aperture section. A measuring unit main body that is used in a cell number counting device that counts the number of cells based on an impedance change between electrodes due to the passage of cells through the aperture unit, and that performs arithmetic processing such as cell number counting; Is provided separately, and has the flow channel and the aperture portion inside, and has one end of the electrode exposed to the outside of the flow channel as a signal extraction portion, and the signal extraction portion is attached to and detached from the measurement unit main body. The connection is possible.

  If it is such, since the cartridge which has a flow path and an aperture part is separated from the main part of a measurement part and constituted so that attachment or detachment is possible, it can make a cartridge into a one-time disposable part. it can.

  As a result, durability is not required for the aperture portion, and it is not necessary to use a hard and expensive material. For example, the cartridge can be made of resin excluding the electrode so that it can be mass-produced and the cost can be reduced. It becomes possible. In addition, since the electrode is used only once, it is not necessary to use an electrode having such a high corrosion resistance. In this respect as well, cost reduction can be promoted. Furthermore, there is no need to perform cleaning or the like, and an effect that maintenance can be significantly reduced can be achieved.

  Further, by providing a flow path on the cartridge side, the measurement unit main body and the cartridge are configured to be only electrically connected via electrodes, so that the liquid to be measured may leak into the measurement unit main body. Absent. Therefore, it is not necessary to keep the inside of the measurement unit main body highly sealed, and the configuration of the measurement unit main body can be simplified.

  In order to promote cost reduction, the cartridge is bonded to a base material having a bottomed groove opened on the surface, and the bottomed groove opening is closed on the surface of the base material, and the flow path is It is preferable that the cover member is formed. This is because the substrate can be mass-produced at low cost by precision injection molding or the like.

  Further, in this case, a thin film electrode is provided on the surface of the cover member on the base material side, and a part of the electrode is formed on the flow path corresponding portion to form the liquid contact portion, and a part of the cover member It is even more preferable that the electrode is protruded from the base material and a part of the electrode is formed on the protruding portion to serve as the signal extraction portion. Electrodes can be formed on the cover member itself at low cost using screen printing, sputtering, etc., and the electrodes provided in the flow path having a fine width and fine depth can be easily formed without using complicated processing. This is because it becomes possible.

  The electrode is preferably made of a carbon thin film from the viewpoint of corrosion resistance. Further, in order to reduce the resistance value as much as possible while maintaining the corrosion resistance, it is more preferable that the conductive metal is formed by carbon coating.

  Even if bubbles are generated due to electrolysis of the electrolyte near the electrode, these bubbles are not allowed to flow only downstream from the electrode and pass through the aperture. In order to prevent detection, it is desirable that the flow path is branched into two on the downstream side from the position where the aperture portion is provided, and the electrodes are respectively arranged in the two branched flow paths.

  In order to make it possible to form the aperture part without using special micromachining processing, etc., and to improve the measurement accuracy by smoothing the flow before and after the aperture part, the aperture part has a flow path upstream and downstream thereof. It is preferable that the cross-sectional area is gradually reduced to be formed in a portion having a minimum diameter.

  As described above, according to the cell number measuring device and the cartridge used in the measuring device according to the present invention, the number of cells contained in the liquid to be measured can be measured easily and at low cost, and the inside of the device can be measured. There is no need for corrosion resistance or high sealing performance, and an effect that it can be configured at low cost can be obtained.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a block diagram showing a schematic configuration of a cell number measuring apparatus 1 according to the present invention, and shows a state where a cartridge 20 is mounted on a measuring unit main body 10. FIG. 2 is a perspective view showing an entire image of the cartridge 20 removed from the measuring unit main body 10, and FIG. 4 is a partially exploded view showing main components forming the cartridge 20. FIG. 3 is a partially enlarged view showing a part of the flow path including the aperture portion 24 formed in the cartridge 20 in an enlarged manner. FIG. 5 is an enlarged view of a portion of the cross section of the flow path where the electrode in the cartridge 20 is formed. FIG. 6 is a schematic side view showing a structure when the sample blood is introduced into the cartridge 20. In the present embodiment, it is assumed that the measurement target liquid is sample blood, and the cells to be counted are blood cells contained in the sample blood.

  As shown in FIG. 1, the cell count device 1 includes a measurement unit body 10 and a plate-like cartridge 20 that is detachably attached to the measurement unit body 10. The measurement unit main body 10 is provided with a mounting unit 11 for mounting the cartridge 20, and a thin specimen blood (hereinafter referred to as “sample blood”) that is a liquid to be measured inside the cartridge 20, separately from the measurement unit main body 10. A liquid supply unit 12 for guiding from a liquid storage tank T (described later), a sensor unit 13 for extracting a signal from the cartridge 20, and an electric signal from the sensor unit 13 are detected and included in the liquid to be measured. And a counting unit 14 that counts the number of cells.

  The mounting portion 11 is formed of a groove-like recess 11 a that is formed slightly larger than the width and thickness of the cartridge 20 and has a predetermined depth according to the shape of the cartridge 20. When the cartridge 20 is mounted, most of the cartridge 20 is accommodated in the recess 11a, leaving a part for gripping the cartridge 20. A protrusion 15 that fits into a notch 21 (see FIGS. 2 and 3) formed at the tip of the cartridge 20 is formed at the back of the recess 11a. In addition, a part (conducting portion 13 a) of the sensor unit 13 that receives an electrical signal in contact with the electrode 26 provided on the cartridge 20 is formed.

  As shown in FIG. 6, the liquid supply unit 12 is mainly composed of a suction pump P and a valve V. This inhalation pump P is connected to a terminal opening 25 of a cartridge flow path 23, which will be described later, when the cartridge 20 is mounted on the mounting section 11, and this is made negative pressure, and a sample blood drop is supplied from the flow path inlet 22 Is sucked into the flow path 23 and guided.

  The sensor unit 13 includes a conductive portion 13a that is electrically connected to the inside of the concave portion 11a of the mounting portion 11, contacts the electrode 26 of the cartridge 20 when the cartridge is mounted, and applies a predetermined voltage between the electrodes 26. The amount of current proportional to the magnitude of the electric resistance generated at the time of application is detected as an electric signal. Then, this electric signal is output to the count unit 14 via a wiring such as a lead wire.

  The counting unit 14 converts an electrical signal output from the sensor unit 13 into a pulse signal, and outputs an electrical circuit (not shown) that outputs the number of blood cells in the sample blood introduced into the flow path 23 and the volume value of the blood cells. ). Then, the signals regarding the number of blood cells and the volume of blood cells output as described above are output to an external display (not shown) or the like.

  Next, the detailed configuration of the cartridge 20 will be described with reference to FIGS.

  As shown in FIG. 2, the cartridge 20 is basically a one-time-use disposable cartridge, and includes a notch 21 having a substantially rectangular cross section on the distal end side in the insertion direction, and the insertion direction from the distal end side. Is provided in the vicinity of the center of the end portion on the side away from the inlet port 22 opened on the surface (upper surface). A flow path 23 formed so as to conduct to the introduction port 22 is configured to extend linearly so as to bisect the entire cartridge from the introduction port 22 toward the distal end side. In the vicinity of the notch 21 on the distal end side, the flow path 23 is brought close to the opposing inner wall of the flow path 23 so as to form a gap of about 1 mm, and an aperture portion 24 is formed by the gap portion. Note that the size of the gap for forming the aperture portion 24 can be determined as appropriate depending on the size of the cell to be measured (blood cell in the present embodiment).

  As shown in FIGS. 2, 3, and 4, the flow path 23 is bifurcated downstream from the position where the aperture portion 24 is formed. Therefore, in the flow path 23 in the vicinity of the aperture section 24, the flow path 23a on the upstream side of the aperture section 24 is configured to gradually narrow the distance between the inner walls facing the aperture section 24. The paths 23b and 23c are configured to gradually increase the distance between the inner walls facing from the aperture section 24. The other parts have substantially the same flow path width. By forming the flow path 23 in this manner, the flow of the sample blood passing through the aperture part 24 is not disturbed, and blood cells contained in the sample blood pass through the aperture part 24 in order.

  The flow paths 23b and 23c on the downstream side of the aperture section 24 will be described. The flow paths 23b and 23c are formed slightly straight along the front end side of the cartridge 20 from the branched position, and then bent. The cartridge advances linearly toward the rear end of the cartridge, and then moves from the rear end to the front end again. This is repeated a plurality of times to form a zigzag. Thus, the flow path 23 is configured to be bent at the end side in the insertion direction of the cartridge 20 in a plurality of times, and is formed over substantially the entire surface of the cartridge 20. Thereby, the flow path 23 is secured as long as possible in a limited area inside the cartridge 20. Further, the final end of the channel 23 communicates with an opening 25 that is opened on the surface (upper surface) of the cartridge 20, similar to the inlet 22, and the sample blood introduced from the inlet 22 passes through the channel 23. The air contained in is pushed out from the opening 25 so as to advance in the flow path 23.

  On the other hand, a pair of electrodes 26 (hereinafter referred to as first electrodes 26) sandwiching the aperture 24 at a position in contact with the sample blood that has passed through the aperture 24, downstream of the aperture 24 at the branch portion of the flow path 23. Also called). The electrode 26 includes a liquid contact portion 26a formed so as to face the inner wall of the flow path 23, a lead wire 26b drawn from the liquid contact portion 26a, and a liquid contact portion via the lead wire 26b. The signal extraction portion 26c is exposed on the surface of the cartridge above the cutout portion 21 so as to be electrically connected to the passage 26a.

  A second electrode 27 is provided on the downstream side of the liquid contact portion 26 a in the first electrode 26. The second electrode 27 includes a liquid detection unit 27a provided on the downstream side (specifically, a predetermined distance upstream from the end of the flow channel 23) where the flow channel capacity from the liquid contact unit 26a becomes a predetermined constant volume. The lead wire 27b drawn out from the liquid detection unit 27a and the detection signal output unit 27c provided on the side of the signal extraction unit 26c that is continuous with the terminal end of the lead wire 27b, Acts as a liquid level sensor for detecting that the liquid has reached the liquid detection unit 27a.

  That is, when the sample blood that travels in the flow path 23 after coming into contact with the liquid contact part 26a comes into contact with the liquid detection part 27a, an electrical signal is generated. Is sent to the detection signal output unit 27c, whereby the measurement unit main body 10 is informed that the sample blood has reached a predetermined arrival position in the flow path 23. Thus, when it is detected that the sample blood has reached the predetermined position in the flow channel 23, the supply of the sample blood by the liquid supply unit 12 is stopped, so that the sample blood is opened at the end of the flow channel. It is possible to prevent overflowing after reaching 25.

  The signal extraction portion 26c of the first electrode 26 and the detection signal output portion 27c of the second electrode 27 are arranged side by side as described above, and when the cartridge 20 is mounted on the measurement unit main body 10. In addition, the signal extraction unit 26 c and the detection signal output unit 27 c are configured to be in electrical contact with the conduction unit 13 a of the sensor unit 13.

  Next, details of the internal configuration of the cartridge 20 will be described with reference to FIG. As shown in FIG. 4, the cartridge 20 includes a rectangular plate-shaped substrate 30 and a film 50 that is a PET cover member that is bonded to the surface 30 a of the substrate 30 via an adhesive layer 40. ing.

  A concave portion for forming the cutout portion 21 of the cartridge 20 is formed in the vicinity of the substantially central portion on the front end side of the base material 30, and a bottomed groove 32 having a width and a depth of about 1 mm opened to the base material surface 30 a. Is formed. In addition, at the start and end of the bottomed groove 32, substantially cylindrical voids 33a, 33b having a slightly expanded area toward the surface of the cartridge so as to form the introduction port 22 and the opening 25 of the cartridge 20, 33c is provided. Further, as described above, in the vicinity of the upstream side of the position where the aperture portion 24 is formed, the width of the bottomed groove 32 is gradually narrowed, and in the vicinity of the downstream side of the position where the aperture portion 24 is formed, The width of the groove 32 is gradually enlarged. Such a bottomed groove 32 may be formed from the substrate surface 30a by an arbitrary processing method such as micromachining, hot embossing, or photomolding. In the case where the substrate 30 is made of resin, Alternatively, it may be formed in advance into a shape having such a groove by a technique such as precision injection molding.

  The film 50 is formed in a rectangular shape that substantially matches the shape of the substrate surface 30a, and the flow path 23 is configured by covering the opening 32a of the bottomed groove 32 when bonded to the substrate surface 30a. In addition, through holes 51a, 51b, 51c that substantially match the shape of the gaps are formed at positions corresponding to the gaps 33a, 33b, 33c formed at the start and end of the bottomed groove 32. Further, the film 50 is not provided with a cutout at a position corresponding to the cutout portion 21 of the base material 30, and when the base material 30 and the film 50 are joined, a part of the film 50 is above the cutout portion 21. Configured to cover. In the area 52 covering the upper portion of the notch 21, a signal extraction part 26 c that is a part of the first electrode 26 and a detection signal output part 27 c that is a part of the second electrode 27 are formed.

Further, as shown in FIG. 5, the above-mentioned first electrode 26 is formed by applying a thin carbon coating (C) to silver (Ag) as a conductive metal applied in a minute amount at a predetermined position on the back surface of the film 50. And the 2nd electrode 27 is formed. As described above, the liquid contact part 26a and the liquid detection part 27a constituting each of these electrodes are electrically connected by contacting with the sample blood flowing in the flow path 23, and further, the liquid contact part 26a and the liquid detection part 27a. detector 27a is electrically connected to the lead wire 26b, each signal receiving portion 26c via 27b and the detection signal output unit 27 c.

  The first electrode 26 and the second electrode 27 formed on the back surface of the film 50 are formed by a method such as screen printing or sputtering. However, it goes without saying that these electrodes can be formed by methods other than those described above. For example, a layer of a mixed material of silver and carbon is deposited on the entire back surface of the film 50, and unnecessary portions of silver are etched or etched. It is possible to form these electrodes even by using a technique such as removing or altering. In this case, an electrode having a smaller film thickness can be formed as compared with the electrode formed by the above-described screen printing or sputtering.

  Further, when the electrical resistance of the liquid contact part 26a and the liquid detection part 27a does not matter so much, the liquid contact part 26a is made of only carbon (C) without applying silver (Ag) as a conductive metal. And the liquid detection part 27a can also be formed.

  Moreover, the adhesive layer 40 for joining the base material 30 and the film 50 is except for the part corresponding to the place in which the through-holes 51a-51c of the film 50, the liquid contact part 26a, and the liquid detection part 27a were formed. The thin-film solid adhesive 40 covers the entire surface of the substrate 30. The solid adhesive 40 is solid at room temperature, but has a property of being melted and sticky when heated to a predetermined temperature or higher. Then, the solid adhesive 40 is sandwiched between the base material 30 and the film 50, and the base material 30 and the film 50 are joined by heating in this state.

  Although details are omitted, the bonding between the base material 30 and the film 50 is performed using diffusion bonding or laser bonding in addition to bonding by precise bonding using the adhesive layer 40 (adhesive) as described above. You can also.

  Next, a procedure for measuring the number of blood cells and the size of blood cells in the sample blood, which is the liquid to be measured, using such a cell number measuring apparatus 1 will be described below.

  As shown in FIG. 6, first, sample blood quantitatively collected with a capillary or the like is mixed in a dilution tank T, and the lower end discharge port of this dilution tank T communicates with the introduction port 22 of the cartridge 20. As described above, the cartridge 20 is coupled via the connection member C.

  Next, the cartridge 20 is mounted on the measurement unit main body 10. At this time, the signal extraction part 26c and the detection signal output part 27c formed on the surface of the cartridge 20 are in contact with the conduction part 13a of the sensor part 13, and the first electrodes 26, 26 of the cartridge 20 and A small amount of current is supplied so that a predetermined voltage is applied to the second electrodes 27 and 27. Initially, since the sample blood is not introduced into the flow path 23 of the cartridge 20, the electrical resistance value between the first electrodes 26 becomes infinite. At this time, the cartridge opening 25 is connected to the liquid supply unit 12.

  Thereafter, the liquid supply unit 12 operates, the opening 25 becomes negative pressure, and the sample blood is sucked into the flow path 23 through the inlet 22 of the cartridge 20.

  When the sample blood supplied into the flow path 23 branches through the aperture section 24 and reaches each of the pair of liquid contact sections 26a, the sensor section 13 passes through the signal extraction section 26c and these liquid contact sections. The electrical resistance value between 26a is detected as an electrical signal. This electrical signal is a pulse signal that is proportional to the electrical resistance value that changes based on the number and volume (diameter) of blood cells in the sample blood that passes through the aperture unit 24, and the sensor unit 13 receives a predetermined value from this electrical signal. The number and volume of blood cells in the sample blood that have passed through the aperture unit 24 over time are calculated and output to an external display or the like.

  Moreover, the sample blood supplied into the flow path 23 passes through the position where the liquid contact portions 26a, 26a of the first electrode are provided, and further, the liquid detection portions 27a, 27a of the second electrode are provided. When the position reaches the position, the sensor unit 13 detects the electric resistance value between the second electrodes 27 as an electric signal via the detection signal output units 27c and 27c. When this electrical signal is detected by the sensor unit 13, the counting is stopped and the switching valve V is operated to switch the opening 25 from the liquid supply unit 12 to communicate with the atmosphere. As a result, the opening 25 is returned to atmospheric pressure, and the suction of the sample blood is stopped.

  Thus, since the flow path capacity from the aperture section 24 to the liquid detection section 27a of the second electrode 27 is set constant, the flow path capacity can be obtained without performing complicated operations such as controlling the flow volume constant. From the count number, the number of blood cells per unit volume of the sample blood can be obtained. Further, the supply of the sample blood can be stopped before the sample blood reaches the opening 25 at the end of the flow path, and a situation in which the sample blood overflows from the opening 25 can be prevented.

  Thus, when the number of blood cells in the sample blood is measured, the cartridge 20 is removed from the mounting portion 11, and the cartridge 20 containing the sample blood is discarded by a predetermined process such as incineration.

  As described above, according to such a cell number measuring apparatus 1, the flow path 23 through which the sample blood that is the liquid to be measured flows is provided only on the cartridge 20 side, and passes through the inside of the measuring unit main body 10. Therefore, there is no need to improve the sealing performance inside the measurement unit main body 10.

  Further, since the cartridge 20 is discarded and a new cartridge 20 is used for each measurement, durability is not required for the aperture section 24, and it is not necessary to use a hard and expensive material. The cartridge 20 is made of resin except for the electrodes 26 and 27 so that it can be mass-produced, and the cost can be reduced. In addition, since the electrode is used only once, it is not necessary to use the electrodes 26 and 27 having a very high corrosion resistance. In this respect as well, cost reduction can be promoted. Furthermore, there is no need to perform cleaning or the like, so that maintenance can be greatly reduced and safety can be improved.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, a cartridge in which the flow path is branched at the aperture portion is disclosed. However, the present invention is not limited to such an embodiment. A portion may be formed, and electrodes may be disposed on the upstream and downstream sides of the aperture portion.

  In the embodiment, the timing of stopping the supply of the liquid to be measured into the flow path is performed by the second electrode provided in the flow path detecting the liquid to be measured. If the length or the like of the formed flow path is known, the amount of liquid to be measured to be supplied into the flow path may be determined in advance. In this case, the liquid to be measured does not overflow from the opening without special detection.

  In addition, the present invention can be variously modified without departing from the gist thereof.

1 is an overall schematic view schematically showing a configuration of a cell number measuring apparatus according to an embodiment of the present invention. It is a perspective view which shows the whole cartridge contained in the cell number measuring apparatus which concerns on the same embodiment. It is the elements on larger scale which expand and show the aperture part of the cartridge concerning the embodiment. It is a perspective view which shows a mode that it decomposed | disassembled for every principal part which comprises the cartridge which concerns on the same embodiment. It is a fragmentary sectional view showing a part of channel which an electrode is formed of a cartridge concerning the embodiment. FIG. 4 is a schematic side view showing a sample blood aspirating operation to a cartridge of the cell number measuring apparatus according to the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cell number measuring device 10 ... Measuring part main body 11 ... Mounting part 13 ... Sensor part 14 ... Count part 20 ... Cartridge 22 ... Inlet 23 ... Flow path 24 ... Aperture part 26 ... 1st electrode (a pair of electrodes)
26a ... Liquid contact part 26c ... Signal extraction part 27 ... Second electrode 30 ... Base material 32 ... Bottomed groove 50 ... Cover member (film)

Claims (5)

A flow path through which a liquid to be measured containing cells flows, an aperture provided on the flow path, and a pair of electrodes each having a liquid contact portion disposed at a position sandwiching the aperture, and the cells pass through the aperture In what counts the number of cells based on the impedance change between the electrodes by
A measurement unit body that performs calculation processing such as cell count,
The flow path and the aperture portion are provided inside, and the one end portion of the electrode is exposed to the outside of the flow channel as a signal extraction portion above the cutout portion having a substantially rectangular cross section formed at the tip portion. A cartridge that is detachably connected to the measurement unit main body at the take-out unit ,
The cartridge includes a base material having a bottomed groove opened on the surface, and a cover member made of a film that is attached to the surface of the base material to close the bottomed groove opening and forms the flow path. Is,
A thin film-like electrode is provided on the base material side surface of the cover member, and a part of the electrode is formed in the flow path corresponding part to form the liquid contact portion, and a part of the cover member is protruded from the base material. A cell number measuring apparatus , wherein a part of the electrode is formed on the protruding part to form a signal extraction part . The cell counting device according to claim 1 , wherein the electrode is configured by coating a conductive metal with a carbon coating. The cell number measuring apparatus according to claim 1 or 2 , wherein the flow path is branched into two on the downstream side from the position where the aperture portion is provided, and the electrodes are respectively disposed in the two branched flow paths. The cell count measuring device according to claim 1, 2 or 3 , wherein the aperture portion is formed in a portion having a minimum diameter by gradually reducing the cross-sectional area of the upstream and downstream flow paths. A flow path through which a liquid to be measured containing cells flows, an aperture provided on the flow path, and a pair of electrodes each having a liquid contact portion disposed at a position sandwiching the aperture, and the cells pass through the aperture It is used for a cell number measuring device that counts the number of cells based on the impedance change between the electrodes,
The electrode is provided separately from the measuring unit main body for performing arithmetic processing such as cell number counting, and has the flow path and the aperture part inside, and above the cutout part having a substantially rectangular cross section formed at the tip part. one end portion is exposed to the flow path outside as signal receiving portion of it by state, and are intended to be detachably connected to the measuring unit body at its signal receiving portion,
A base material having a bottomed groove opened on the surface, and a cover member made of a film that is attached to the surface of the base material to close the bottomed groove opening and forms the flow path. Yes,
A thin film-like electrode is provided on the base material side surface of the cover member, and a part of the electrode is formed in the flow path corresponding part to form the liquid contact portion, and a part of the cover member is projected from the base material. , the cartridge characterized that you have a signal receiving portion forms part of the electrode to the protruding portion.