Tank for introducing liquid drop thereinto and analyzing device

A liquid droplet introducing tank 3A includes a tank body 31, which is formed by mutually opposing top surface 31a and bottom surface 31b, and a side surface 31c. The tank also includes an injection hole 32 that is opened in the top surface 31a. Liquid droplets Dr are injected from the injection hole 32. The center of the injection hole 32 is closer to the side surface 31c than the center of the top surface 31a. The liquid droplet introducing tank 3A enables liquid droplets to be suitably injected therein and is suitable for reducing size.

TECHNICAL FIELD

The present invention relates to a liquid droplet introducing tank and an analyzing device using the same.

BACKGROUND ART

Analyzing specific components of blood is effective for determining the state of health of a human body or treating a specific disease. Examples of blood analyzers used for such applications are blood cell counters that count blood cells such as erythrocytes or leukocytes in blood.

FIG. 26shows an example of an analyzing device installed in a conventional blood cell counter. The analyzing device X shown in the drawing is provided with a body91, a diluent tank92, an introduction portion93, a dilution tank94, a recovery tank95, a weighing tank96, and an aspiration port98. When blood99is introduced into an introduction port93a, the blood99permeates into flow paths93cand93dby capillary phenomenon. When a rotating member93bis rotated by 90° while in this state, the portion of the blood99contained in the flow path93dis separated. Next, when aspirated from the aspiration port98, a diluent92ain the diluent tank92and the blood99in the flow path93dare sent to the dilution tank94. The diluent92aand the blood99are mixed during the course of being sent to the dilution tank94. As a result, diluted blood is formed in the dilution tank94.

A partition wall97with tiny holes or pores formed therein is provided between the dilution tank94and the recovery tank95. As aspiration from the aspiration port98continues, the diluted blood within the dilution tank94flows into the recovery tank95through the micropore. Electrodes94aand95aare provided in the dilution tank94and the recovery tank95. Resistance between the electrodes94aand95ais monitored as the diluted blood passes through the micropore. Since erythrocytes, for example, are insulators, resistance decreases each time an erythrocyte passes through the micropore. The total number of erythrocytes contained in the diluted blood can be determined by counting the number of times resistance decreases. The diluted blood that has flowed into the recovery tank95is further sent to the weighing tank96. Flow rate detection means (not shown) comprised of electrical or optical means is provided in front of or in back of the weighing tank96in the direction of flow. The amount of diluted blood that has been measured can be obtained by this flow rate detection means. The total number of erythrocytes in the blood99is thus counted by using this procedure. The analyzing device X has a comparatively simple structure, and is composed as a so-called disposable type of analyzing device that is used only once and then disposed of.

However, the analyzing device X is required to contain the diluent92ain a state suitable for analysis. For example, if a minute gap forms in the analyzing device X, there is the risk of leakage of the diluent92a. In addition, in the case of employing a configuration in which the diluent92ais sealed in the diluent tank92, it is necessary to provide means for suitably pumping the diluent92aby releasing the sealed state when using the analyzing device X. In this manner, it is not easy to suitably contain the diluent92ain the analyzing device X.Patent Document 1: WO 03/104771

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

With the foregoing in view, an object of the present invention is to provide a liquid droplet introducing tank and an analyzing device, which have a compact size and enable liquid droplets to be suitably injected therein.

Means for Solving the Problems

According to a first aspect of the present invention, there is provided a liquid droplet introducing tank provided with: a tank body that is formed by a pair of mutually opposing surfaces, and a side surface that spreads out in a direction in which the pair of surfaces are spaced apart; and an injection hole that is opened in one of the pair of surfaces, where liquid droplets are injected from the injection hole, and the center of the injection hole is closer to the side surface than the center of the surface of the pair of surfaces that has the opening.

In a preferable embodiment of the present invention, a portion of an inner surface of the injection hole and a portion of the side surface are flush with each other.

In a preferable embodiment of the present invention, a hydrophilic region that demonstrates hydrophilicity greater than that of other portions is formed on at least one of the pair of surfaces and the side surface.

In a preferable embodiment of the present invention, at least a portion of the hydrophilic region is provided at a location that does not overlap with the opening when viewed in the direction in which the pair of surfaces are spaced apart.

In a preferable embodiment of the present invention, the hydrophilic region is formed by applying at least a drying reagent or a liquid to at least one of the pair of surfaces and the side surface.

In a preferable embodiment of the present invention, at least one of the pair of surfaces is formed with a resistance boundary line that generates a resistance force against the progression of liquid droplets beyond the resistance boundary line, and that extends from a location that overlaps with the opening to a location that does not overlap with the opening when viewed in the direction in which the pair of surfaces are spaced apart.

In a preferable embodiment of the present invention, at least a portion of the side surface is not perpendicular to at least one of the pair of surfaces.

In a preferable embodiment of the present invention, the pair of surfaces are not parallel to each other.

In a preferable embodiment of the present invention, the surface of the pair of surfaces that has the opening is further formed with a rib that surrounds at least a portion of the opening and protrudes toward the surface of the pair of surfaces that does not have the opening.

In a preferable embodiment of the present invention, the surface of the pair of surfaces that has the opening is provided with a swelling member that surrounds at least a portion of the opening and swells by absorbing a portion of the liquid droplets.

In a preferable embodiment of the present invention, the surface of the pair of surfaces that has the opening is formed with a hydrophobic region that surrounds at least a portion of the opening.

According to a second aspect of the present invention, there is provided an analyzing device provided with a liquid droplet introducing tank according to the first aspect of the present invention. The analyzing device is configured to be installed in an analyzer that analyzes specimens containing the liquid droplets injected from the liquid droplet introducing tank.

Other characteristics and advantages of the present invention will be made clearer from the following detailed explanation while referring to the attached drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

The following provides a detailed explanation of preferred embodiments of the present invention with reference to the drawings.

FIG. 1shows an example of an analyzing device relating to the present invention. An analyzing device A of the present embodiment is composed to be able to be installed in an analyzer (not shown) that carries out cell counting or optical analyses, and is a so-called disposable type of analyzing device for the analyzer. The analyzing device A is composed by laminating a transparent plate1and a bottom plate2, and is provided with a liquid droplet introducing tank3A, which is a liquid droplet introducing tank based on a first embodiment of the present invention, a blood introduction portion61, a dilution tank62, a blood cell counting portion63, an optical analysis portion64and a connector7.

The transparent plate1is a rectangular-shaped plate that is composed of a transparent resin such as acrylic or polyethylene. A plurality of indentations or grooves for forming flow paths or reservoirs to be described later are formed in the transparent plate1. The bottom plate2is, for example, a printed wiring board in which a plurality of base materials composed of epoxy resin and the like are laminated and a wiring pattern composed of copper foil and the like is formed between these base materials. The connector7is formed in an extending portion of the bottom plate2. The connector7is used to connect the analyzing device A to the analyzer. The transparent plate1and the bottom plate2are joined using an adhesive, for example, to be liquid-tight. In addition, both the transparent plate1and the bottom plate2have hydrophobic surfaces that repel water comparatively easily. Furthermore, the bottom plate2may be formed with PET, for example, in the case is not necessary to electrical wiring in the bottom plate2.

The blood introduction portion61is for introducing blood to be analyzed into the analyzing device A. This introduction of blood is carried out by, for example, injecting blood sampled from a subject with a dropper and the like. Blood that has been introduced into the introducing portion61is pumped into microchannels by differential pressure generated by pressurization means (not shown) such as a pump provided in the analyzer.

The dilution tank62provides a location for diluting blood introduced from the blood introduction portion61to a concentration suitable for each type of analysis. A prescribed amount of blood is pumped into this diluent tank62along with diluent introduced from the liquid droplet introducing tank3A. Diluted blood for use as a specimen to be analyzed is obtained by mixing and agitating this blood and diluent.

The blood counting portion63is composed to be able to carry out cell counting on the diluted blood using, for example, an electrical resistance detection method, and has a micropore (not shown) provided in a microchannel and a pair of electrodes (not shown) on both sides of this micropore. The pair of electrodes is composed of one or a plurality of types of materials selected from the group consisting of, for example, gold, platinum, palladium and carbon, and is formed in the bottom plate2by a printing technique.

The optical analysis portion64is a site for measuring Hb or CRP, for example, using an optical technique, and has a reflective film (not shown) provided in a flow path portion enlarged into roughly a circular shape. This reflective film is composed of one type or a plurality of types of materials selected from the group consisting of, for example, gold, platinum and palladium, and is collectively formed in the bottom plate2with the electrodes using a printing technique. This reflective film is coated with a reagent (not shown). This reagent makes it possible to measure Hb or CRP by an optical technique when mixed with the diluted blood.

The liquid droplet introducing tank3A is a site for injecting, for example, pure water for forming diluted blood into the analyzing device A in the form of liquid droplets, and has a tank body31and an injection hole32. As shown inFIG. 2, the tank body31is a comparatively shallow tank having a circular cross-section, and is formed by a top surface31a, a bottom surface31band a side surface31c. The top surface31aand the side surface31cconstitute the inner surfaces of an indentation having a circular cross-section formed in the transparent plate1. The bottom surface31bis a region of the bottom plate2that covers the indentation. In the present embodiment, the diameter of the tank body31is about 8 mm and the depth is about 2 mm.

The injection hole32is a through hole that is opened in the top plate31aof the tank body31, and is a site where liquid droplets Dr of pure water pass through from, for example, a nozzle Nz provided in the analyzer. The center of the injection hole32is offset from the center of the tank body31. In the present embodiment, as shown inFIGS. 2 and 3, a portion of an inner surface32aof the injection hole32and a portion of the side surface31cof the tank body31are flush with each other, i.e., arranged within the same plane. The diameter of the injection hole32is about 4 mm.

A drying reagent4is applied to the inner surface31b. The drying reagent4consists of a mixture of a salt and a polymer compound such as polyvinylpyrrolidone (PVP), and is for forming physiological saline suitable for diluting blood by being dissolved in the injected pure water. The drying reagent4is obtained by absorbing liquid droplets Dr and completely dissolving therein, the hydrophilicity thereof with respect to the liquid droplets Dr is considerably higher than the inner surface31b, and corresponds to an example of a hydrophilic region as referred to in the present invention. In the present embodiment, the drying reagent4is coated in the form of six small circles. As is clearly depicted inFIG. 3, one of the small circular portions is coated at a location that completely overlaps with the injection hole32. The other five small circular portions are coated at locations that are completely or nearly completely hidden from the injection hole32.

The following provides an explanation of the operation of the analyzing device A and the liquid droplet introducing tank3A.

FIG. 4shows a reference example for comparing injection of liquid droplets into the liquid droplet introducing tank3A in the analyzing device A. The liquid droplet introducing tank3A′ of this reference example is provided with a tank body31′ and an injection hole32′ that are similar to the previously described tank body31and the injection hole32. However, the centers of the tank body31′ and the injection hole32′ are arranged to mutually coincide, and this differs from the previously described liquid droplet introducing tank3A. In addition, differing from the liquid droplet introducing tank3A, a drying reagent4is not coated in the liquid droplet introducing tank3A′.

As shown inFIG. 5, when liquid droplets Dr are injected from the injection hole32′, the liquid droplets Dr accumulate in a portion directly below the injection hole32in a state in which they contact the top surface and bottom surface that form the tank body31′. This is because the liquid droplets Dr are inhibited from spreading out from the injection hole32′ since surface tension acts on the liquid droplets Dr to make the surface area thereof as small as possible. When liquid droplets Dr are further injected, the liquid droplets Dr gradually spread out over the tank body31′. As shown inFIG. 6, a portion of the liquid droplets Dr reach a side surface of the tank body31′. When injection is subsequently continued, the contact surface area between the liquid droplets Dr and the side surface increases. However, since surface tension acts on the liquid droplets Dr so as to make the surface area thereof as small as possible, the surface area of the liquid droplets Dr gradually increases without hardly any deviation from the injection hole32′. When injection of the liquid droplets Dr continues further, the entire injection hole32′ is completely blocked by the liquid droplets Dr as shown inFIG. 7.

It is no longer possible to continue to inject the liquid droplets Dr beyond this point. At this time, space within the tank body31′ that is not filled by the liquid droplets Dr becomes a residual space Ls. In the liquid droplet introducing tank3A′, since the liquid droplets Dr hardly deviate at all from the center of the injection hole32′, namely the center of the tank body31′, the injection hole32′ ends up being blocked by the liquid droplets Dr before the liquid droplets Dr fully spread out in the tank body31′. Consequently, the residual space Ls easily accounts for a comparatively large proportion of the tank body31′. As the size of the residual space Ls increases, it becomes necessary to make the volume of the tank body31′ much larger than a desired amount of liquid droplets Dr in order to inject that desired amount. This situation impairs reducing the size of the liquid droplet introducing tank3A′ and in turn, the size of the analyzing device in which it is contained. There is a strong need to reduce the size of disposable type analyzing devices in particular in order to respond to requirements such as ease of use and cost reductions.

In contrast, the following provides an explanation of injecting liquid droplets Dr into the liquid droplet introducing tank3A of the analyzing device A of the present embodiment with reference toFIGS. 8 to 11.

First, as shown inFIG. 8, liquid droplets Dr are injected from the injection hole32. Since the injection hole32is located off-center from the tank body31to a degree such that a portion of the inner surface32athereof and a portion of the side surface31care arranged within the same plane, the liquid droplets Dr rapidly contact the side surface31c. As injection of the liquid droplets Dr continues, the liquid droplets Dr spread out so as to follow the side surface31cas shown inFIG. 9. In addition, wetting force generated at those portions of the liquid droplets Dr in contact with the top surface31aand the bottom surface31bacts to inhibit the liquid droplets Dr from spreading out. However, when the liquid droplets Dr contact the drying reagent4, the drying reagent4immediately absorbs the liquid droplets Dr. As a result, the liquid droplets Dr spread out so as to be attracted to the drying reagent4.

As injection of the liquid droplets Dr continues further, spreading along the side surface31cand spreading through contact with the drying reagent4occur alternately or simultaneously. As a result of the liquid droplets Dr being actively forced to spread out, accumulation of the liquid droplets Dr in the vicinity of the injection hole32can be prevented. As a result, complete blockage of the injection hole32by the liquid droplets Dr can be avoided.

As injection of the liquid droplets Dr continues further, the state shown inFIG. 11is reached. When in this state, the liquid droplets Dr spread out to a degree that they contact all of the drying reagents4. In addition, the majority of the side surface31cis wetted by the liquid droplets Dr. As a result, the residual space Ls of the tank body31can be made to be quite small as compared with, for example, the residual space Ls in the reference example shownFIG. 7. This is advantageous for reducing the size of the tank body31and in turn, the analyzing device A, and is suitable for using the analyzing device A as a disposable type of analyzing device.

FIGS. 12 to 23indicate other embodiments of the present invention. Furthermore, the same reference symbols as those used in the present embodiment are used in these drawings to indicate those constituent features that are identical or similar to the constituent features of the above-mentioned embodiment.

FIGS. 12 and 13show a liquid droplet introducing tank based on a second embodiment of the present invention. A liquid droplet introducing tank3B of the present embodiment differs from the previously described embodiment in that a metal film5is formed on the bottom surface31binstead of the previously described drying reagent4. The metal film5is composed of one type or a plurality of types of materials selected from the group consisting of, for example, gold, platinum, palladium and carbon, and is formed on the bottom plate2by a printing technique. This metal film5can be collectively formed with electrodes of the above-mentioned blood cell counting portion63or a reflecting portion of the optical analysis portion64. As is clearly depicted inFIG. 12, the metal film5covers a region that is roughly more than half of the bottom surface31b. The edge of the metal film5forms a resistance boundary line51.

As shown inFIG. 13, the resistance boundary line51constitutes a minute level difference formed on the bottom surface31b. This resistance boundary line51demonstrates a resistance force that inhibits spreading of the liquid droplets Dr when the liquid droplets Dr attempt to spread out from the bottom surface31bto the metal film5. Since the liquid droplets Dr do not easily go beyond the resistance boundary line51, during initial injection of the liquid droplets Dr, the liquid droplets Dr rapidly contact the side surface31cand spread out along the side surface31cover a region not covered by the metal film5. Since the resistance boundary line51extends from a region overlapping with the injection hole32to a region not overlapping with the injection hole32, the liquid droplets Dr do not accumulate at the injection hole32, but rather spread out from the injection hole32to a region not overlapping with the injection hole32. When nearly the entire region not covered by the metal film5is filled by the liquid droplets Dr, the liquid droplets Dr spread out over the metal film5in opposition to the resistance force generated by the resistance boundary line51. This spreading occurs along the side surface31c. The formation of a gradually curved shape along the side surface31cby the portion of the resistance boundary line51in the vicinity of the right side of the drawing is suitable for causing the liquid droplets Dr to spread out along the side surface31c.

Instead of forming the metal film5, an adhesive layer for adhering the transparent plate1and the bottom plate2, for example, may be formed in the same region as the metal film5as means for forming the resistance boundary line51. The adhesive used for such applications is made of resin that demonstrates strong hydrophobicity in the majority of cases. Moreover, similar to the case of providing the metal film5, the resistance boundary line51has a level difference that corresponds to the thickness of the adhesive. Liquid droplets Dr can be suitably injected in the case of providing this type of resistance boundary line51as well.

FIG. 14shows a liquid droplet introducing tank based on a third embodiment of the present invention. In a liquid droplet introducing tank3C of the present embodiment, means for providing a hydrophilic region differs from the previously described embodiments. A liquid supply hole33is provided in the liquid droplet introducing tank3C. The liquid supply hole33is a hole having a comparatively small cross-section that is opened in the side surface31c. A liquid supply source not shown is connected to the liquid supply hole33. As shown inFIG. 15, a liquid is supplied from the liquid supply source to the tank body31through the liquid supply hole33either simultaneous to or before or after the start of injection of liquid droplets Dr from the injection hole32. The amount of the liquid is an amount to a degree that those portions of the top surface31a, the bottom surface31band the side surface31cin the vicinity of the liquid supply hole33become wet. As a result, those regions of the top surface31a, the bottom surface31band the side surface31cthat are wetted by the liquid constitute a hydrophilic region. This hydrophilic region promotes spreading of the liquid droplets Dr that have been injected from the injection hole32, and is suitable for enabling the liquid droplets Dr to spread out evenly within the tank body31.

FIG. 16shows a liquid droplet introducing tank based on a fourth embodiment of the present invention. A liquid droplet introducing tank3D of the present embodiment differs from the previously described embodiments in that a portion of the side surface31cis non-parallel to the top surface31aand the bottom surface31b. The portion of the side surface31cof the present embodiment in the vicinity of the injection hole32is inclined, and more specifically, an angle θ formed by the side surface31cand the bottom surface31bis an acute angle. According to this embodiment, contact surface area between liquid droplets Dr injected from the injection hole32and the bottom surface31band the side surface31cincreases by the amount of inclination of the side surface31c. As a result, a stronger wetting force acts on the liquid droplets Dr, thereby making it possible to expect the effect of the liquid droplets Dr more readily spreading out along the side surface31c. Furthermore, although the liquid droplets Dr easily spread out along the side surface31cif the angle θ is an acute angle, the present invention is not limited thereto, but rather the angle θ is only required to be set so that the wetting force acting on the liquid droplets Dr acts advantageously for allowing the liquid droplets Dr to spread out.

FIG. 17shows a liquid droplet introducing tank based on a fifth embodiment of the present invention. A liquid droplet introducing tank3E of the present invention differs from the previously described embodiments in that the top surface31aand the bottom surface31bare not parallel. More specifically, the top surface31ais inclined slightly relative to the horizontally level bottom surface31b. Moreover, the top surface31ais inclined in the radial direction of the tank body31from the location where the injection hole32opens towards the bottom surface31bmoving towards the opposite side from the injection hole32. According to this embodiment, liquid droplets Dr that have been injected from the injection hole32easily spread out towards portions farther away from the injection hole32. This is because the contact surface area increases the closer the top surface31ais to the bottom surface31beven for liquid droplets Dr of the same volume, and this results in a corresponding increase in wetting force.

FIGS. 18 and 19show a liquid droplet introducing tank based on a sixth embodiment of the present invention. A liquid droplet introducing tank3F of the present embodiment differs from the previously described embodiments in that it has a rib34. The rib34surrounds the opening32and protrudes from the top surface31atowards the bottom surface31b.

When liquid droplets Dr are injected into this liquid droplet introducing tank3F, the liquid droplets Dr spread out between the side surface31cand the rib34as shown inFIG. 20. This is because the level difference formed by the rib34functions as a barrier that inhibits the droplets Dr from flowing into the injection hole32. Consequently, as injection of the liquid droplets Dr continues, the liquid droplets Dr selectively spread out over the region between the side surface31cand the rib34as shown inFIGS. 21 and 22. During the course of this spreading, air that was present within the tank body31is rapidly evacuated from the injection hole32. The entire region between the side surface31cand the rib34can be then be filled by the liquid droplets Dr as shown inFIG. 23. According to this type of embodiment, the residual space Ls can be nearly completely eliminated. Furthermore, the rib34is not limited to a perfect circle, but rather is only required to surround at least a portion of the opening32. Consequently, the rib34may be arranged in the shape of a letter “C” in which a portion of the circle is missing, or may be arranged so that a plurality of small projections surrounds the opening32in the form of a ring.

FIG. 24shows a liquid droplet introducing tank based on a seventh embodiment of the present invention. A liquid droplet introducing tank3G of the present embodiment differs from the previously described embodiments in that it is provided with a swelling member35. The swelling member35is composed of a material in which the volume thereof swells to several times to several hundred times its initial volume as a result of absorbing a portion of the liquid droplets Dr. Examples of such materials that may be used include Aquacork (Sumitomo Seika Chemicals), Wonder-Gel (Kao), Sanwet (Sanyo Chemical Industries) and Aqua Reserve GP (Nippon Synthetic Chemical Industry). The swelling member35is provided on the top surface31a, and is in the form or a ring that surrounds at least a portion of the opening32. When liquid droplets Dr are injected into the opening32, the swelling member35swells from the top surface31atowards the bottom surface31bas a result of absorbing a portion of the liquid droplets Dr (as indicated with a virtual line in the drawing). This type of configuration also makes it possible to prevent the opening32from being blocked by the liquid droplets Dr.

FIG. 25shows a liquid droplet introducing tank based on an eighth embodiment of the present invention. A liquid droplet introducing tank3H of the present embodiment differs from the previously described embodiments in that it has a hydrophobic region36. The hydrophobic region36is formed in a portion of the top surface31athat surrounds the opening32. The hydrophobic region36is a portion that demonstrates stronger hydrophobicity with respect to liquid droplets Dr than portions of the top surface31aother than the hydrophobic region36, and is formed by carrying out hydrophobic treatment on a portion of the top surface31a. This type of configuration also makes it possible to prevent the opening32from being blocked by the liquid droplets Dr.

The liquid droplet introducing tank and analyzing device relating to the present invention are limited to the previously described embodiments. The design of the specific configuration of each portion of the liquid droplet introducing tank and analyzing device relating to the present invention may be altered in various ways.

The shapes of the tank body31and the injection hole32are not limited to the shapes having a circular cross-section described above, but rather are only required to have a shape that is suitable for injection of liquid droplets Dr. Although arranging the relative locations of the tank body31and the injection hole32such that a portion of the side surface31cand a portion of the inner surface32alie within the same plane as previously described is suitable for allowing the liquid droplets Dr to promptly contact the side surface31c, the present invention is not limited thereto. The liquid droplets Dr can be promoted to contact the side surface31cif the center of the injection hole32is arranged to be closer to the side surface31cthan the center of the tank body31(top surface31a). The drying reagent4is not limited to the so-called salt reagent previously described, but rather is only required to be that which demonstrates satisfactory hydrophilicity with respect to the liquid droplets Dr. In addition, means for providing a hydrophilic region as referred to in the present invention is not limited to the formation of the drying reagent4, but rather hydrophilic treatment may also be carried out on a portion of the bottom surface31b, for example. So-called ultraviolet treatment, by which a surface is modified by using ultraviolet light, may also be used for the hydrophilic treatment. Applications of the liquid droplet injections tanks3A to3F are not limited to being provided in the analyzer analyzing device A, but rather include use in all types of devices into which liquid droplets Dr are injected. The analyzing device A relating to the present invention is not limited to blood analysis applications, but rather can naturally also be widely used in applications such as using injected liquid droplets Dr to make dilutions or using liquid droplets Dr directly as specimens, as well as in applications other than so-called medical applications.