The present invention relates to a test container and a nucleic acid test method.
A test container, such as a test cartridge or an analysis chip, which is used to perform various analyses on a sample extracted from a biological sample, is known. For example, the test container includes a plurality of chambers (liquid storage portions) that store liquid and flow channels that connects the chambers. In this test container, a sample or a reagent is fed using an external force, such as electromagnetic force or centrifugal force.
JP2019-515308A discloses a microfluidic chip that feeds a specimen (a sample solution) put in from a specimen inlet (an inlet) provided at one end of a specimen chamber from the specimen chamber to a mixing chamber with a centrifugal force. The microfluidic chip disclosed in JP2019-515308A includes a circuit, that is, a vent flow channel, which is adapted to provide an air connection between the specimen chamber and the mixing chamber, to be capable of smoothly feeding liquid.
Since the microfluidic chip disclosed in JP2019-515308A includes the vent flow channel, the microfluidic chip can smoothly feed liquid. On the other hand, in a case of an analysis that requires treatment at a heating temperature of 90° C. or higher in a downstream chamber, vaporized sample solution may escape to the vent flow channel. For this reason, a test error caused by a shortage in the amount of the sample solution in the downstream chamber, or the like may occur. JP2019-515308A discloses that heating treatment is performed in the downstream chamber to which the sample solution is fed for pretreatment or the like of the sample solution. However, since a heating temperature is as low as about 65° C., there is no consideration for a shortage in the amount of the sample solution which is caused by the vaporization of the sample solution.
The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a test container and a nucleic acid test method that can suppress the occurrence of a test error caused by a shortage in the amount of sample solution in a test container for feeding liquid with a centrifugal force.
A test container according to the present disclosure is a test container including an inlet into which a sample solution is to be put, a first chamber in which the sample solution to be fed from the inlet is stored, and a second chamber in which the sample solution to be fed from the first chamber is stored. The test container is attached to a centrifuge and the sample solution is transferred from the first chamber to the second chamber in order by a centrifugal force caused by a rotation of the centrifuge. The test container comprises: an attachable and detachable lid part that covers the inlet; a liquid reservoir portion that stores the sample solution put in from the inlet in front of the first chamber; and a valve that is disposed between the first chamber and the second chamber, includes a liquid storage portion temporarily storing the sample solution to be fed from the first chamber to the second chamber, and is capable of switching between a first state where the first chamber and the liquid storage portion communicate with each other and the second chamber and the liquid storage portion do not communicate with each other, a second state where the second chamber and the liquid storage portion communicate with each other and the first chamber and the liquid storage portion do not communicate with each other, and a third state where both of the first chamber and the second chamber do not communicate with the liquid storage portion. A volume of the liquid reservoir portion is larger than a volume of the first chamber, the first chamber and the liquid reservoir portion are connected to each other only by a liquid flow channel through which the sample solution is fed, the first chamber and the second chamber are connected to each other only by a liquid flow channel through which a sample solution is fed, and a vent flow channel through which gas is released from the first chamber is not provided.
It is preferable that, in a case where the volume of the liquid reservoir portion is denoted by V1, the volume of the first chamber is denoted by V2, a volume of the liquid storage portion is denoted by V3, and a volume of the second chamber is denoted by V4, a relationship of “V1>V2>V3>V4” is satisfied.
A reagent to react with the sample solution may be stored in the first chamber, the liquid storage portion, or the second chamber.
A reagent that contains an amplification reagent for amplifying a specific nucleic acid sequence and a probe for determining a nucleic acid sequence can be used as the reagent.
The probe may be a fluorescent probe.
A nucleic acid test method according to the present disclosure is a nucleic acid test method using the test container according to the aspect of the present disclosure in which the reagent is stored in the liquid storage portion. The test method comprises: putting the sample solution in from the inlet of the test container in an initial state where the valve is in the second state or the third state, to store the sample solution in the liquid reservoir portion; hermetically sealing the inlet with the lid part; feeding the sample solution from the liquid reservoir portion to the first chamber with a centrifugal force; heating the first chamber to perform heating treatment of the sample solution; switching the valve to the first state; feeding the sample solution from the first chamber to the liquid storage portion of the valve with a centrifugal force to mix the sample solution and the reagent in the liquid storage portion; switching the valve to the second state; feeding a liquid mixture of the sample solution and the reagent from the liquid storage portion to the second chamber with a centrifugal force; switching the valve to the third state or the first state; controlling a temperature of the liquid mixture in the second chamber to amplify the specific nucleic acid sequence contained in the liquid mixture; irradiating the liquid mixture with excitation light to detect fluorescence generated from the fluorescent probe; and determining whether or not the specific nucleic acid sequence is present or a concentration of the specific nucleic acid sequence.
According to the test container and the nucleic acid test method of the present disclosure, it is possible to suppress the occurrence of a test error caused by a shortage in the amount of sample solution.
Embodiments of the present disclosure will be described in detail below with reference to the drawings. The scale and the like of each component shown in the drawings are appropriately changed from the actual ones. In each drawing, the same components are denoted by the same reference numerals.
The test container 10 is a microchannel device including a flow channel structure 11 that includes a plurality of chambers and flow channels connecting the chambers. The test container 10 is attached to a centrifuge, and liquid in the test container 10 is transferred from the chamber to the chamber by a centrifugal force caused by the rotation of the centrifuge. The test container 10 of this example is a test container that is loaded into a test device 100 (see
The test container 10 includes a body member 10A in which recessed portions, holes, and the like forming a part of the flow channel structure 11 including the flow channels and the chambers are formed, and a bottom member 10B that forms bottom surfaces of the flow channels (see
As long as a material of the body member 10A is a publicly known resin molding plastic material, the material can be used without being particularly limited. However, polycarbonate, polypropylene, cycloolefin, or a silicone resin is preferable from the viewpoint of heat resistance and transparency.
The bottom member 10B is formed of, for example, a thin plate or a film. As long as a material of the bottom member 10B is a publicly known resin molding plastic material, the material can be used without being particularly limited. However, the same material as the body member 10A is preferable from the viewpoint of adhesiveness to the body member 10A. Although details will be described later, from the viewpoint of being capable of improving adhesion to a heating unit and efficiently performing heating in a case where a first chamber 15 and a second chamber 16 are to be heated, it is preferable that the bottom member 10B is formed of a film. Portions of the body member 10A that form the first chamber 15 and the second chamber 16 close to an upper surface may also be formed of a film.
The test container 10 comprises an inlet 12, a lid part 12A, a liquid reservoir portion 13, a first chamber 15, a second chamber 16, a valve 20 that is disposed between the first chamber 15 and the second chamber 16 and includes a liquid storage portion 24, and flow channels 18a to 18c that connect the liquid reservoir portion 13, the first chamber 15, and the second chamber 16. The plurality of chambers comprised in the test container 10 are the liquid reservoir portion 13, the first chamber 15, the second chamber 16, and the liquid storage portion 24. Hereinafter, in a case where it is not necessary to distinguish the liquid reservoir portion 13, the first chamber 15, the second chamber 16, and the liquid storage portion 24, the liquid reservoir portion 13, the first chamber 15, the second chamber 16, and the liquid storage portion 24 may be collectively referred to as a chamber.
In the test container 10, the volume of the liquid reservoir portion 13 is larger than the volume of the first chamber 15.
Further, the first chamber 15 and the liquid reservoir portion 13 are connected to each other only by a liquid flow channel through which a sample solution 40 is fed, the first chamber 15 and the second chamber 16 are connected to each other only by a liquid flow channel through which a sample solution 40 is fed, and a vent flow channel through which gas is released from the first chamber 15 is not provided.
In the schematic view of the flow channel structure shown in
In a case where a volume of the liquid reservoir portion 13 is denoted by V1, a volume of the first chamber 15 is denoted by V2, a volume of the liquid storage portion 24 is denoted by V3, and a volume of the second chamber 16 is denoted by V4 in the flow channel structure 11 (or the flow channel structure 11A) of the test container 10, a relationship of “V1>V2>V3>V4” is satisfied. That is, the chambers are formed such that a chamber disposed closer to an outer diameter side from an inner diameter side close to a rotation axis of the centrifuge has a smaller volume.
For example, the volume V1 of the liquid reservoir portion 13 exceeds 100 μL and is 200 μL or less, the volume V2 of the first chamber 15 is 100 μL, the volume V3 of the liquid storage portion 24 is 50 μL, and the volume V4 of the second chamber 16 is 30 μL.
The inlet 12 is an opening into which a sample solution 40 is to be put. The lid part 12A is a lid part that covers the inlet 12 and can be attached to and detached from the opening of the inlet 12. In this example, the lid part 12A is formed to be capable of being screwed to an end portion of a tubular portion 14 that forms the inlet 12. Methods of attaching and detaching the lid part are not particularly limited, and the lid part 12A may be attached to and detached from the tubular portion 14 using, for example, a snap type cap structure or a pressure sensitive adhesive. The lid part 12A allows the inlet 12 to be open in a case where the sample solution is to be put in, but closes the inlet 12 to exclude the mixing of contaminants from the outside and to prevent the vaporization of the sample solution 40 from the inside in cases other than a case where the sample solution is to be put in. The sample solution 40 is liquid that is obtained after nucleic acid is extracted from a sample collected from, for example, a nasal cavity, a pharynx, an oral cavity, an affected area, and the like of a subject.
In the following description, a surface on which the inlet 12 is provided will be referred to as an upper surface of the test container 10 and a side corresponding to the bottom member 10B will be referred to as a lower surface of the test container 10. Here, an upper surface of the body member 10A is the same as the upper surface of the test container 10, a lower surface of the body member 10A is a surface that is in contact with an upper surface of the bottom member 10B, and a lower surface of the bottom member 10B is the same as the lower surface of the test container 10.
The liquid reservoir portion 13 is provided at a position facing the inlet 12 and stores the sample solution 40 dropped from the inlet 12. The shape of the liquid reservoir portion 13 is not particularly limited, and a columnar shape, a conical shape, a truncated conical shape, and the like can be arbitrarily selected as the shape of the liquid reservoir portion 13.
In this test container 10, the inlet 12 is formed of the opening of the tubular portion 14 that is formed to penetrate the body member 10A in a thickness direction and to protrude from the upper surface of the body member 10A, and the liquid reservoir portion 13 is formed by an inner side portion of the tubular portion 14 in the body member 10A and the bottom member 10B. The liquid reservoir portion 13 is a space for storing the sample solution 40, which is put in from the inlet 12, in front of the first chamber 15.
The first chamber 15 is a chamber that can store liquid, and is a chamber in which the sample solution 40 to be fed from the inlet 12 via the liquid reservoir portion 13 is stored. The first chamber 15 is formed by the recessed portion, which is provided on the lower surface of the body member 10A, and the bottom member 10B.
As described above, the volume V1 of the liquid reservoir portion 13 is larger than the volume V2 of the first chamber 15. In this example, the inlet 12 of this example is an opening of the tubular portion 14 and has a diameter equal to the diameter of the liquid reservoir portion 13. The test container 10 is not provided with a vent flow channel through which gas is released from the first chamber 15. For this reason, since the inlet 12 is clogged with the sample solution 40 at the time of putting in the sample solution 40 from the inlet 12 in a case where an opening diameter of the inlet 12 is small, there is no place for the air in the liquid reservoir portion 13 to go. Accordingly, it is difficult to smoothly put in the sample solution 40. In the test device 100, the inlet 12 has an opening diameter enough to allow air in the liquid reservoir portion 13 to be discharged from the inlet 12 while being exchanged with the sample solution 40 in a case where the sample solution 40 is to be put in from the inlet 12.
Since the test container 10 is not provided with a vent flow channel through which gas is released from the first chamber 15, there is no place for air in the flow channel 18a and the first chamber 15 to escape at the time of putting in the sample solution 40. For this reason, the sample solution 40 put in from the inlet 12 is stored in the liquid reservoir portion 13 without being fed to the first chamber 15.
The first chamber 15 is, for example, a chamber to be subjected to pretreatment for a test, and is subjected to heating treatment performed by a first heating unit 120 in the test device 100 (see
The second chamber 16 is a chamber that can store liquid, and is a chamber in which the sample solution 40 to be fed from the first chamber 15 is stored. In this example, the sample solution 40 is fed to the second chamber 16 from the first chamber 15 via the liquid storage portion 24 of the valve 20 to be described later. The second chamber 16 is formed by the recessed portion, which is provided on the lower surface of the body member 10A, and the bottom member 10B.
The second chamber 16 is, for example, a chamber to be subjected to a reaction and detection processing for a test, and is subjected to heating treatment performed by a second heating unit 122 in the test device 100 (see
As shown in
The valve 20 of this test container 10 includes a rotating member 25 disposed in a tubular portion 22 consisting of a cylindrical recessed portion that is provided on the upper surface of the body member 10A and a portion that surrounds the recessed portion and protrudes from the upper surface of the body member 10A. The rotating member 25 is a cylindrical member having an outer diameter slightly smaller than an inner diameter of the tubular portion 22, and is rotatably installed in the tubular portion 22. The liquid storage portion 24 is provided in the rotating member 25, and one hole 24a communicating with the liquid storage portion 24 is provided on a bottom surface of the rotating member 25. A bottom surface of the tubular portion 22 includes a hole 22a that communicates with the flow channel 18b and a hole 22b that communicates with the flow channel 18c. Each of the holes 22a and 22b is provided with an O-ring 26. An upper surface of the rotating member 25 is provided with a knob 25a that is used to rotate the rotating member 25.
The O-ring 26 has a function to prevent leakage from a connection portion between the hole 24a and the hole 22a or the hole 22b in a case where the hole 24a of the bottom surface of the rotating member 25 and any one of the hole 22a or the hole 22b of the bottom surface of the tubular portion 22 coincide with each other and the liquid storage portion 24 communicates with the flow channel 18b or the flow channel 18c. A publicly known sealing member, such as a packing or a gasket, can be used as a sealing element for preventing leakage without particularly limited in addition to the O-ring 26. For example, rubber materials, such as nitrile rubber, urethane rubber, silicon rubber, and fluororubber, or publicly known elastomer, such as olefin and urethane, can be used as a material of the sealing part. Further, the sealing element may be integrally molded with the rotating member 25 or the tubular portion 22 of the body member 10A.
The rotating member 25 can be rotated to set a state where the hole 24a of the bottom surface of the rotating member 25 and the hole 22a of the bottom surface of the tubular portion 22 coincide with each other, a state where the hole 24a and the hole 22b coincide with each other, and a state where the hole 24a coincides with neither of the hole 22a and the hole 22b.
Each of the flow channels 18a to 18c is formed by the recessed portion, which is provided on the lower surface of the body member 10A, and the bottom member 10B. The flow channel 18a is a flow channel that connects the liquid reservoir portion 13 and the first chamber 15. The flow channel 18b is a flow channel that connects the first chamber 15 and the liquid storage portion 24 of the valve 20. The flow channel 18b communicates with the hole 22a of the bottom surface of the tubular portion 22 of the valve 20. The flow channel 18c is a flow channel that connects the second chamber 16 and the liquid storage portion 24 of the valve 20. The flow channel 18c communicates with the hole 22b of the bottom surface of the tubular portion 22. A size of the cross section of each of the flow channels 18a to 18c is, for example, about 0.5 mm to 1 mm in width and 0.5 mm in depth.
In
As shown in
A state where the hole 24a of the bottom surface of the rotating member 25 coincides with neither of the hole 22a and the hole 22b of the bottom surface of the tubular portion 22 as shown in
As described above, the valve 20 is a rotary valve that can switch between the first state, the second state, and the third state in a case where the rotating member 25 is rotated in the tubular portion 22 of the body member 10A. The valve 20 may be any valve as long as the first state to the third state can be realized, and is not limited to the rotary valve having the above-described structure.
For example, the test container 10 is set on a loading portion 111A of a disk-shaped support 111 shown in
The sample solution 40 put in from the inlet 12 is fed from the liquid reservoir portion 13 to the first chamber 15, is fed from the first chamber 15 to the liquid storage portion 24, and is fed from the liquid storage portion 24 to the second chamber 16, respectively, by a centrifugal force caused by the rotation of the centrifuge 110.
An action of the test container 10 will be described with a liquid feeding procedure with reference to
The sample solution 40 is put in from the inlet 12 (see
In a state where the lid part 12A covers the inlet 12, a centrifugal force is applied to the test container 10 to feed the sample solution 40 from the liquid reservoir portion 13 to the first chamber 15 (Step STB). Since the centrifugal force is applied, gas-liquid exchange occurs between the sample solution 40 stored in the liquid reservoir portion 13 and air present in the first chamber 15 and the sample solution 40 is fed from the liquid reservoir portion 13 to the first chamber 15. The sample solution 40 that does not enter the first chamber 15 remains in the liquid reservoir portion 13.
The first chamber 15 is heated to a high temperature by the first heating unit 120 to perform pretreatment of the sample solution 40 (Step STC). For example, the first chamber 15 is heated to 90° C. or higher. Air bubbles 41 are generated in the sample solution 40 stored in the first chamber 15 due to this high-temperature heating, some of the sample solution 40 is vaporized, and particles 40g generated due to the vaporization are moved to the liquid reservoir portion 13. The particles 40g moved to the liquid reservoir portion 13 are cooled and liquefied in the liquid reservoir portion 13 and are stored in the liquid reservoir portion 13 as a sample solution 40.
After the high-temperature heating, the valve 20 is operated to switch to the first state where the first chamber 15 and the liquid storage portion 24 communicate with each other, and a centrifugal force is applied to the test container 10, which is in the first state, to feed the sample solution 40 to the liquid storage portion 24 (Step STD). Since the centrifugal force is applied, gas-liquid exchange occurs between the sample solution 40 stored in the first chamber 15 and air present in the liquid storage portion 24 and the sample solution 40 is fed from the first chamber 15 to the liquid storage portion 24. At this time, the sample solution 40 returned to the liquid reservoir portion 13 during high-temperature heating is also fed to the liquid storage portion 24 via the first chamber 15 by a centrifugal force. Here, since the amount of the sample solution 40 is larger than the capacity of the liquid storage portion 24, the liquid storage portion 24 is filled with the sample solution 40.
After that, the valve 20 is operated to switch to the second state where the first chamber 15 and the liquid storage portion 24 do not communicate with each other and the second chamber 16 and the liquid storage portion 24 communicate with each other, and a centrifugal force is applied to the test container 10, which is in the second state, to feed the sample solution 40 to the second chamber 16 (Step STE). Since the centrifugal force is applied, gas-liquid exchange occurs between the sample solution 40 stored in the liquid storage portion 24 and air present in the second chamber 16 and the sample solution 40 is fed from the liquid storage portion 24 to the second chamber 16. Since the volume V3 of the liquid storage portion 24 is larger than the volume V4 of the second chamber 16 in this example, the second chamber 16 is filled with the sample solution 40.
As described above, the volume of the liquid reservoir portion 13 is larger than the volume of the first chamber 15 in the test container 10 according to the present embodiment. Further, in the test container 10, the first chamber 15 and the liquid reservoir portion 13 are connected to each other only by a liquid flow channel through which the sample solution 40 is fed, the first chamber 15 and the second chamber 16 are connected to each other only by a liquid flow channel through which the sample solution 40 is fed, and a vent flow channel through which gas is released from the first chamber 15 is not provided. According to such a configuration, the amount of the sample solution 40 larger than the volume of the first chamber 15 can be stored in the liquid reservoir portion 13. Therefore, after that, even though some of the sample solution 40, which is vaporized in a case where the first chamber 15 is heated to a high temperature for the pretreatment of the sample solution 40 in a state where the sample solution 40 is stored in the first chamber 15, returns to the liquid reservoir portion 13, a sufficient amount of the sample solution 40 can be fed from the first chamber 15 to the second chamber 16 (here, to the liquid storage portion 24) by a centrifugal force thereafter. Since it is possible to suppress the occurrence of a shortage of the sample solution 40 to be fed to the second chamber 16, it is possible to suppress a test error. Furthermore, in a case where a vent flow channel which is connected to the liquid storage portion 24 or the second chamber 16 and through which gas is released from the first chamber 15 is provided, the vaporized sample solution 40 may enter the liquid storage portion 24 or the like first. In a case where a reagent is provided in the liquid storage portion 24 or the second chamber 16 and needs to react with an appropriate amount of the sample solution 40 appropriately subjected to the pretreatment, the reagent is diluted by the sample solution 40 that has been vaporized and entered the liquid storage portion 24 or the like first. For this reason, there is a possibility that a test error may occur. However, since the test container 10 according to the present embodiment does not comprise a vent flow channel through which gas is released from the first chamber 15, it is possible to suppress a test error that is caused by the dilution of the reagent or the like.
In a case where the volume of the liquid reservoir portion 13 is denoted by V1, the volume of the first chamber 15 is denoted by V2, the volume of the liquid storage portion 24 is denoted by V3, and the volume of the second chamber 16 is denoted by V4 in the flow channel structure 11 of this test container 10, a relationship of “V1>V2>V3>V4” is satisfied.
In a case where the volume V1 of the liquid reservoir portion 13 is larger than the volume of the first chamber 15 as described above, the liquid reservoir portion 13 can store the sample solution 40 more than the volume V2 of the first chamber 15. Further, in a case where a relationship between the volumes of the plurality of chambers arranged from the inner diameter side toward the outer diameter side of the centrifuge satisfies “V1>V2>V3>V4”, the chamber disposed on the outer diameter side can be filled with the sample solution 40 in a case where the sample solution 40 is fed from the chamber disposed on the inner diameter side of the centrifuge to the chamber disposed on the outer diameter side. For this reason, it is possible to suppress the occurrence of the shortage of the sample solution 40 in the second chamber 16 finally used for the detection.
As shown in
A stirring rod for promoting the mixing of the sample solution 40 and the reagent 32 may be included in the chamber in which the reagent 32 is stored or a chamber that is provided on the downstream side thereof.
The test container 10 according to the embodiment includes one flow channel structure 11 from the inlet 12 to the second chamber 16. As a test container 50 of a modification example, one test container 50 may comprise a plurality of flow channel structures 11 as shown in
Further, a plurality of second chambers 16a to 16c may be provided as in a test container 52 of a modification example shown in
Each of the flow channel structures of the test containers 10, 50, and 52 described above may further comprise a deformable chamber that communicates with the second chamber 16. In a case where the deformable chamber is deformed by being pressed from the outside or the like, the second chamber 16 communicating with the deformable chamber can be pressurized. In a case where the second chamber 16 is pressurized, a temperature rising property and a cooling property of liquid stored in the second chamber 16 can be improved. Further, in a case where the second chamber 16 is pressurized, the vaporization of the liquid stored therein can be suppressed during heating.
The test device 100 into which the test containers 10 are loaded and which is used to perform a test will be described with reference to
The test device 100 comprises a centrifuge 110, a first heating unit 120, a second heating unit 122, a valve control unit 124, and a detection unit 126.
The centrifuge 110 comprises a seat 112 that is provided with a rotation mechanism such as a motor, a disk-shaped support 111 that is provided with loading portions 111A (see
The first heating unit 120 is provided to be movable between a position where the first heating unit 120 is in contact with a bottom surface of the first chamber 15 of the test container 10 set on the disk-shaped support 111 and a position where the first heating unit 120 is separated from the bottom surface of the first chamber 15. While the disk-shaped support 111 is rotating, the first heating unit 120 is disposed at a position where the first heating unit 120 is separated from the bottom surface of the first chamber 15. In a state where the disk-shaped support 111 is stopped, the first heating unit 120 is disposed at a position where the first heating unit 120 is in contact with the bottom surface of the first chamber 15. The first heating unit 120 heats liquid stored in the first chamber 15. Here, the liquid to be stored in the first chamber 15 is the sample solution 40. The first heating unit 120 heats the sample solution 40 to a high temperature of, for example, 90° C. or higher for pretreatment.
The second heating unit 122 is provided to be movable between a position where the second heating unit 122 is in contact with a bottom surface of the second chamber 16 of the test container 10 set on the disk-shaped support 111 and a position where the second heating unit 122 is separated from the bottom surface of the second chamber 16. While the disk-shaped support 111 is rotating, the second heating unit 122 is disposed at a position where the second heating unit 122 is separated from the bottom surface of the second chamber 16. In a state where the disk-shaped support 111 is stopped, the second heating unit 122 is disposed at a position where the second heating unit 122 is in contact with the bottom surface of the second chamber 16. The second heating unit 122 heats liquid stored in the second chamber 16. Here, the liquid to be stored in the second chamber 16 is, for example, a liquid mixture of the sample solution 40 and the reagent 32. The second heating unit 122 heats the liquid mixture of the sample solution 40 and the reagent 32 to facilitate the amplification of a nucleic acid.
The second heating unit 122 comprises a Peltier element or the like and is adapted to be capable of controlling a temperature, and performs a temperature cycle in a nucleic acid amplification step. On the other hand, the first heating unit 120 does not require the temperature cycle performed by the second heating unit 122, and is formed of, for example, a heater. A publicly known heating mechanism can be used as a heating mechanism used for each of the first heating unit 120 and the second heating unit 122, and the heating mechanism is not particularly limited.
The valve control unit 124 comprises a mechanism that controls the valve 20 to switch a communication state between the first chamber 15, the second chamber 16, and the liquid storage portion 24 to the first state, the second state, and the third state. The valve control unit 124 comprises, for example, a grip part that grips the knob 25a of the rotating member 25, a rotation mechanism that rotates the grip part in a state where the grip part grips the knob 25a, and a processor that drives the rotation mechanism as necessary in a test processing step.
The detection unit 126 detects whether or not an object to be detected is contained in the sample solution 40 in the second chamber 16. As shown in
An LED, a laser, or the like is used as the light source 126a. The wavelength selective filter 126b is a filter that transmits only light, which has a wavelength corresponding to the excitation wavelength of the probe, of the light emitted from the light source 126a. For example, a photodiode, a photomultiplier, or the like is applied as the photodetector 126c.
A test device 101 shown in
The test device 101 and the test device 102 comprise centrifuges 110A and 110B, which have structures different from the structure of the centrifuge 110 of the test device 100, respectively.
The test device 101 shown in
In the test device 102 shown in
The test container 10 can also be applied in the case of a centrifuge having any configuration of various centrifuges 110, 110A, and 110B shown in
In the above description, the test devices 100, 101, and 102 have been described as test devices used for a nucleic acid test accompanied by nucleic acid amplification treatment. In a case where the first heating unit 120, the second heating unit 122, and the detection unit 126 of each of the test devices 100, 101, and 102 are adapted to be suitable for various tests, the test devices 100, 101, and 102 can be used for various tests other than a nucleic acid test.
A nucleic acid test method according to an embodiment using the test container 10 according to the above-described embodiment will be described with reference to
First, as shown in
The sample 40a is collected from, for example, a nasal cavity, a pharynx, the inside of an oral cavity, or an affected area of an examinee using a collection tool. Alternatively, the sample 40a is body fluid, such as a washing solutions in a nasal cavity, a pharynx, or an oral cavity, saliva, urine, or blood. A publicly known nucleic acid extraction method can be used as a nucleic acid extraction method without particular limitation. Examples of the nucleic acid extraction method include a method using a surfactant or a chaotropic substance and a method of applying physical shear, such as an ultrasonic wave or a bead mill.
In an initial state before the sample solution 40 is put into the test container 10, the valve 20 is set to the second state or the third state where at least the first chamber 15 and the liquid storage portion 24 do not communicate with each other. In the present embodiment, the valve 20 is set to the third state where neither of the first chamber 15 and the second chamber 16 communicates with the liquid storage portion 24. In the test, first, a dropping cap 66 provided with a filter 64 for removing coarse impurities is attached to a container 63 that stores the sample solution 40 containing the sample 40a from which nucleic acid has been extracted in the extraction solution as described above while the valve 20 remains in the initial state, and the sample solution 40 filtered by the filter 64 is put in from the inlet 12 of the test container 10 (Step ST1). The sample solution 40 is stored in the liquid reservoir portion 13.
After the sample solution 40 is completely put in, the inlet 12 is closed by the lid part 12A and an inner space of the test container 10 is hermetically sealed (Step ST2). The test container 10 is loaded into the test device 100 in a state where the sample solution 40 is put in and the inlet 12 is closed by the lid part 12A. The following processing is performed in the test device 100.
The test container 10 is rotated by the centrifuge 110 of the test device 100, and the sample solution 40 is fed from the liquid reservoir portion 13 to the first chamber 15 (Step ST3). The sample solution 40 stored in the liquid reservoir portion 13 and air present in the first chamber 15 are exchanged with each other due to a difference between a centrifugal force applied to the sample solution 40 and a centrifugal force applied to the air, so that the sample solution 40 is transferred to the first chamber 15.
After that, the first chamber 15 is heated by the first heating unit 120 to perform the pretreatment of the sample solution 40 using heating treatment (Step ST4). The ProK contained in the sample solution 40 is deactivated by the heating treatment. The heating temperature is, for example, preferably 80° C. or higher, more preferably 85° C. or higher, and still more preferably 90° C. or higher. An upper limit temperature is preferably 100° C. or lower and more preferably 95° C. or lower from the viewpoint of vaporization of the sample solution.
After the pretreatment, the valve 20 is switched to the first state by the valve control unit 124 (see
Next, the test container 10 is rotated by the centrifuge 110 of the test device 100 and the sample solution 40 is fed from the first chamber 15 to the liquid storage portion 24 of the valve 20 (Step ST6). The reagent 32 is stored in the liquid storage portion 24, and the fed sample liquid 40 and the reagent 32 are mixed with each other in the liquid storage portion 24.
After the sample solution 40 and the reagent 32 are mixed with each other, the valve 20 is switched to the second state by the valve control unit 124 (see
Then, the test container 10 is rotated by the centrifuge 110 of the test device 100 and a liquid mixture 42 of the sample solution 40 and the reagent 32 is fed from the liquid storage portion 24 of the valve 20 to the second chamber 16 (Step ST8).
After the liquid mixture 42 is fed to the second chamber 16, the valve 20 is switched to the third state by the valve control unit 124 (see
Here, the liquid mixture 42 is subjected to nucleic acid amplification treatment and fluorescence detection in a state where the second chamber 16 and the liquid storage portion 24 do not communicate with each other (Step ST10).
The nucleic acid amplification treatment is treatment of heating the liquid mixture 42, which is stored in the second chamber 16, by the second heating unit 122 to amplify a specific nucleic acid sequence. A nucleic acid amplification treatment method is not limited, and for example, an RT-PCR method or a PCR method is used. In a case where a PCR method is used, a step of dissociating a double-stranded DNA into a single-stranded DNA at a high temperature (thermal denaturation step), a step of lowering a temperature and binding a primer to the single-stranded DNA (annealing step), and a step of newly synthesizing a double-stranded DNA by polymerase using the single-stranded DNA as a template (elongation step) are repeated. Examples of a temperature cycle of the thermal denaturation step, the annealing step, and the elongation step include 20 to 50 repetitions of one cycle of the thermal denaturation step performed for 1 minute at a temperature of 94° C., the annealing step performed for 1 minute at a temperature of 50 to 60° C., and the elongation step performed for 1 to 5 minutes at a temperature of 72° C. Further, the thermal denaturation step and the annealing step may be performed at one temperature. Examples of such a temperature cycle include 20 to 50 repetitions of one cycle of the thermal denaturation step and the annealing step performed for 1 minute at a temperature of 94° C. and the elongation step performed for 1 minute at a temperature of 60° C. The temperature and time of the temperature cycle of the amplification step are not particularly limited and are arbitrarily selected depending on the performance of polymerase or a primer.
The fluorescence detection is performed by the detection unit 126 disposed above the second chamber 16. Excitation light L1 having a specific wavelength is emitted into the second chamber 16 from the light source 126a via the wavelength selective filter 126b. Fluorescence L2, which is excited by the excitation light L1 and is generated from a fluorescent probe, is detected by the photodetector 126c. For example, in a case where the nucleic acid amplification treatment is a PCR method, fluorescence detection is performed for each cycle of the temperature cycle and is monitored in real time.
In a case where a specific nucleic acid sequence is present in the sample solution 40, the nucleic acid sequence is amplified in the amplification step and a fluorescent probe labeled with this specific nucleic acid sequence is irradiated with the excitation light L1, so that the fluorescence L2 is detected. On the other hand, in a case where a specific nucleic acid sequence is not present in the sample solution 40, the fluorescence L2 is not detected even though the excitation light L1 is applied. Accordingly, it is possible to determine whether or not a specific nucleic acid sequence is present.
According to the test method using the test container 10, the sample solution 40 fed from the liquid reservoir portion 13 to the first chamber 15 is subjected to pretreatment using high-temperature heating in the first chamber 15. Since the test container 10 does not comprise a vent flow channel, the sample solution 40 does not escape to a portion other than the liquid reservoir portion 13 even though being vaporized, and the sample solution 40 returned to the liquid reservoir portion 13 can be fed to the second chamber 16 again by centrifugal force. Therefore, it is possible to suppress a test error without causing a shortage in the amount of the sample solution 40 to be finally treated in the second chamber 16.
In the test method using the test device 100, whether or not a nucleic acid is present is determined by a fluorescence method using a fluorescent probe. However, a method of determining whether or not a nucleic acid is present is not limited to the fluorescence method, and other detection methods, such as a nucleic acid chromatography method, a light scattering method, a sequencing method, and an electrochemical method, may be used. These methods can be realized by the appropriate change of the detection unit, and the test container may be provided with a reagent containing a probe corresponding to each detection method instead of the fluorescent probe.
A nucleic acid test has been exemplified as an example of a gene test using the test container 10 in the above description, but the test container 10 can be applied not only to the nucleic acid test but also to other gene tests, microbiological tests, and the like.
An example in which the test container 10 is used for a β-glucan test will be described as an example of the microbiological test with reference to
A sample and pretreatment liquid are mixed with each other to prepare a sample solution 40. A dropping cap 66 provided with a filter 64 is attached to a container 63 that stores the sample solution 40, and the sample solution 40 filtered by the filter 64 is put in from the inlet of the test container 10 (Step ST11). The sample solution 40 is stored in the liquid reservoir portion 13.
After the sample solution 40 is completely put in, the inlet 12 is closed by the lid part 12A and an inner space of the test container 10 is hermetically sealed (Step ST12). The test container 10 is loaded into the test device 100 in a state where the sample solution 40 is put in and the inlet 12 is closed by the lid part 12A. The following processing is performed in the test device 100.
The test container 10 is rotated by the centrifuge 110 of the test device 100, and the sample solution 40 is fed from the liquid reservoir portion 13 to the first chamber 15 (Step ST13). The sample solution 40 stored in the liquid reservoir portion 13 and air present in the first chamber 15 are exchanged with each other due to a difference between a centrifugal force applied to the sample solution 40 and a centrifugal force applied to the air, so that the sample solution 40 is transferred to the first chamber 15.
After that, the first chamber 15 is heated by the first heating unit 120 to perform temperature control for increasing the temperature of the sample solution 40 to 70° C. for 10 minutes and then cooling the sample solution 40 to 3° C. (Step ST14). Pretreatment to be performed here is treatment of heating the sample solution 40 and stopping the reaction cascade of endotoxin.
After the pretreatment, the valve 20 is switched to the first state by the valve control unit 124 (see
Next, the test container 10 is rotated by the centrifuge 110 of the test device 100 and the sample solution 40 is fed from the first chamber 15 to the liquid storage portion 24 of the valve 20 (Step ST16). The reagent 32 is stored in the liquid storage portion 24, and the fed sample liquid 40 and the reagent 32 are mixed with each other in the liquid storage portion 24. The reagent 32 is a lyophilized reagent, and is dissolved and mixed with the sample solution 40.
After the sample solution 40 and the reagent 32 are mixed with each other, the valve 20 is switched to the second state by the valve control unit 124 (see
Then, the test container 10 is rotated by the centrifuge 110 of the test device 100 and a liquid mixture 42 of the sample solution 40 and the reagent 32 is fed from the liquid storage portion 24 of the valve 20 to the second chamber 16 (Step ST18).
After the liquid mixture 42 is fed to the second chamber 16, the valve 20 is switched to the third state by the valve control unit 124 (see
Here, an LAL reaction is detected on the liquid mixture 42 by a colorimetric method in a state where the second chamber 16 and the liquid storage portion 24 do not communicate with each other (Step ST20). The detection using the colorimetric method is performed by the detection unit 126 disposed above the second chamber 16. Irradiation light L having a specific wavelength is emitted into the second chamber 16 from the light source 126a via the wavelength selective filter 126b. The photodetector 126c detects the absorbance (or transmittance) of the irradiation light L to detect the LAL reaction.
As described above, the same effect can be obtained using the test container 10 as in the case of the nucleic acid test even in the β-glucan test.
The entire content of the present disclosure of Japanese Patent Application No. 2022-057527, filed Mar. 30, 2022, is incorporated in this specification by reference. All documents, patent applications, and technical standards disclosed in this specification are incorporated in this specification by reference so that the incorporation of each of the documents, the patent applications, and the technical standards by reference is specific and is as detailed as that in a case where the documents, the patent applications, and the technical standards are described individually.
Number | Date | Country | Kind |
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2022-057527 | Mar 2022 | JP | national |
This application is a continuation of International Application No. PCT/JP2023/007398, filed on Feb. 28, 2023, which claims priority from Japanese Patent Application No. 2022-057527, filed on Mar. 30, 2022. The entire disclosure of each of the above applications is incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2023/007398 | Feb 2023 | WO |
Child | 18893976 | US |