The present invention relates to an analysis device.
In the human genome project spending a budget of 3 billion dollars between 1990 and 2005, techniques and methods required for decoding the genomes have been left as a legacy. These techniques have been further improved ever since, and in the present day, the genomes can be decoded at a cost of substantially 1,000 dollars with a level of accuracy that can withstand for practical use.
The core of next-generation sequence measurement is a flow chip to which many micro reaction fields are fixed. A chemical reaction is performed on the micro reaction field fixed onto the flow chip, and a fluorescent signal emitted therefrom is analyzed, so that the base sequence of the nucleic acid can be analyzed. A flow chip is a consumable article of slide glass to which many micro reaction fields are fixed, and includes a fluid channel having an inlet port and an outlet port of reagent. 10 to 40 types of reagents such as enzymes required for base elongation reactions, nucleotides modified by multiple different fluorochromes, a reagent for decomposing a protecting group blocking elongation, and an imaging buffer filling a flow chip fluid channel during imaging are passed through the inlet port and the outlet port to the flow chip. A typical example of a micro reaction field explained here includes beads of 1 μm.
After a reagent is supplied, it may be necessary to control the temperature of the reagent in the flow chip in accordance with the type of the reagent in the fluid channel in the flow chip. This is necessary to advance the chemical reaction accurately and efficiently, and the flow chip is brought into close contact with an aluminum plate generally called a neat block, so that the temperature of the flow chip is adjusted within 10 to 80 degrees Celsius. The supply of the reagent and the temperature adjustment operation are advanced in a stepwise manner, and a fluorescent nucleotide for a single base can be retrieved into the DNA on the micro reaction field. Subsequently, optical measurement is performed. In general, one side of the flow chip is in close contact with the heat block that performs temperature adjustment, and therefore, an object lens is disposed at the other side of the flow chip. When an excitation light is emitted to the micro reaction field on the flow chip substrate via the object lens, fluorescence is emitted. This fluorescence is captured by a two-dimensional sensor such as a CMOS camera, so that fluorescence information about many micro reaction fields fixed on the flow chip substrate can be obtained as images.
Subsequently required is to move the measurement vision field of the flow chip with respect to the optical axis of the fixed object lens. More specifically, the heat block to which the flow chip is fixed is fixed to an XY stage, and the XY stage is driven for a certain distance, so that an adjacent panel is successively positioned on the optical axis. Accordingly, the flow chip peripheral portion is a portion where a component and an operation for controlling the reagent supply, the temperature control, the optical detection, and the stage drive are locally concentrated in a condensed manner. Therefore, it is necessary to prevent each component from, mechanically colliding and interfering with each other, and it is necessary to smoothly perform driving.
On the other hand, an application of a next-generation sequencer to diagnosis is rapidly advancing. One of important issues in expanding the next-generation sequencer technique in the diagnosis field includes a reduction of the diagnosis cost. Under such circumstances, the reduction of the cost of a flow chip which is a consumable article is a key to reduce the diagnosis cost. More specifically, the reduction in the size of the flow chip is the problem to be solved.
In order to solve the above problem, PTL 1 discloses a configuration in which a fluid channel is diverged in a flow chip, so that the inlet port and the outlet port are brought closer to each other in the fluid channel system. According to this configuration, the positions of the fluid channel connection components on the flow chip can be converged, so that the number of the positions of the fluid channel connection components on the flow chip can be reduced from two to one. Accordingly, this can reduce the number of portions where the object lens and the fluid channel connection unit interfere with each other, and realize a reduction in the size of the flow chip. More specifically, the size of the flow chip was 75 mm by 25 mm, but this is reduced to a size of 30 mm by 15 mm. Further, PTL 1 also describes a flow chip cartridge for holding a flow chip in view of operability of the flow chip.
On the other hand, an area of a flow chip that can be measured with a single image will be referred, to as a single panel. The size of a single flow chip is 30 mm by 15 mm, but as indicated by NPL 1, the number of panels measured is 14 panels. The size of a single panel is up to 0.75 mm by 0.75 mm according to liberal estimates, and therefore, the area used for the optical measurement is 10.5 mm by 0.75 mm. More specifically, only 2% of the area of the flow chip is actually used for the optical measurement. Therefore, the margin for further reducing the size of the flow chip is still large. In PTL 1, the reason why the fluid channel is caused to diverge is that the number of panels is limited to 12 by 1. More specifically, the panels are disposed only in one row direction, and the stage drive is limited to only the X direction, and so that the fluid channel is caused to diverse in the flow chip. In a case where the flow chip is configured to be driven in two directions of X and Y, the configuration for forming the diverging fluid channel cannot increase the size of the flow chip because of fluid channel walls. In the configuration for forming a diverging fluid channel, the fluid channel becomes complicated, and therefore, the cost increases. Therefore, the fluid channel diverging method of PTL 1 is effective only in a case where the number of panels is limited to about 10, and the throughput is limited, and the applicable application is limited to those having a low throughput.
The reason why a size of 30 mm is required in the longitudinal direction of the flow chip is the following reasons. It is necessary to install a heat block at one surface of the flow chip for temperature adjustment, and it is necessary to perform supply of a reagent and perform optical detection on the other surface of the flow chip. Therefore, in order to avoid mechanical interference between the object lens and the fluid channel connection unit of the flow chip, the size of the flow chip is required to be equal to more than a certain size. Therefore, in the past, it used to be difficult to reduce the size of the flow chip.
The index regarded as important in the next-generation sequence development is the throughput. The throughput is the total number of bases that can be input per run, and in order to increase this, techniques have been developed. In the past, the reaction field is randomly scattered and fixed on the flow chip substrate. However, the configuration of random fixing has several problems such as (1) since the reaction fields are close to each other at a certain chance, it is difficult to analyze reaction fields close to each other by resolution or more, and (2) since the distance between bright spots is random, the effect of crosstalk between bright spots is different for each bright spot, and there is a large variation in the detection accuracy. In order to cope with such problems, what attracts attention recently is a technique capable of arranging the reaction fields on a substrate in a matrix manner.
NPL 2 describes a technique for arranging aminosilane films on a silicon substrate in a matrix manner by using a semiconductor lithography technique, NPL 3 describes a method for arranging samples on a substrate in a matrix manner for a single molecule sequencer. According to the present technique, holes called nano apertures are formed on a glass substrate by using light lithography. The nano apertures are formed on a substrate regularly according to a semiconductor lithography technique. The diameter of the nano aperture is shorter than the wavelength, and therefore, the excitation light for exciting fluorescent single molecules fixed to the nano aperture cannot directly pass through the nano aperture. However, because of leaked light, only a very small area in proximity to the nano aperture can be illuminated. Because of this effect, the fluorochromes floating in a solution is prevented from being excited, and the excitation light can be emitted to only a small area to be detected. Accordingly, a single molecule real time sequence can be achieved. In the single molecule real time sequence, a vision filed is fixed during sequence reaction, and the reaction is captured continuously at a high speed with a frame rate of 100 Hz with a two-dimensional camera. Therefore, it is not necessary to replace the reagent in the reaction.
The technique for regularly arranging the reaction fields on the flow chip explained above greatly contributes to the increase of the throughput, and at the same time, the cost required for production of the substrate also increases. A conventional substrate used for random fixing does not require a lithography step, but in order to regularly arrange reaction fields on the substrate, a lithography step is required. This makes the increase in the cost of the flow chip, i.e., a consumable article, inevitable. Therefore, in this case, it is also necessary to avoid interference between the object lens and the fluid channel connection unit, and to avoid the increase in the cost because of the reduction in the size of the flow chip.
PTL 1: US 2012/0270305 A1
NPL 1: “MiSeq System User Guide”, Part #15027617, Rev. F, Illumina, Inc., November 2012, pages 8, 13
NPL 2: Science. 2010 Jan. 1; 327 (5961):78-81
NPL 3: Proc Natl Acad Sci USA. 2008 Jan. 29; 105 (4):1176-81
In the conventional sequence measurement, it is necessary to install a heat block at one surface of the flow chip for temperature adjustment, and it is necessary to perform supply of a reagent and perform, optical detection on the other surface of the flow chip. Therefore, in order to avoid mechanical interference between the object lens and the fluid channel connection unit of the flow chip, the size of the flow chip is required to be equal to more than a certain size, and it used to be difficult to reduce the cost of the flow chip, which, is a consumable article.
It is an object of the present invention to provide an analysis device capable of reducing the size of a flow chip while avoiding mechanical interference between the object lens and the fluid channel connection unit of the flow chip.
In order to achieve the above object, for example, a configuration described in claims is employed. The present application includes multiple means for solving the above problems, but if an example thereof is shown, an analysis device including a flow chip at least including a first substrate having light transparency and a second substrate having an inlet port and an outlet port for a fluid, a holding member for holding the flow chip, a fixing member where the holding member is disposed, and which comes into contact, with the second substrate of the flow chip, a fluid supply unit which supplies the fluid to the inlet port, and which discharges the fluid from the outlet port, an optical detection unit disposed at a side of the first substrate of the flow chip, and a drive unit driving the holding member in an XY direction is provided.
According to the present invention, the size of a flow chip can be reduced, and therefore, the cost required for the flow chip can be reduced.
Further features related to the present invention would be clarified from the description and the appended drawings of the present specification. The problems, configurations, and the effects other than the above would be clarified from the following explanation about the embodiments.
Hereinafter, an embodiment of the present invention will be explained with reference to appended drawings. It should be noted that the appended drawings illustrate specific embodiments based on the principal of the present invention, but these are given for the sake of understanding of the present invention, and should not be used, for interpreting the present invention in a limited manner. The embodiment described below relates to an analysis device, and more specifically, the embodiment relates to a nucleic acid sequence analysis device for interpreting a base sequence of nucleic acid such as DNA or RNA.
In contrast,
The substrate 103 of the flow chip 100 is a silicon substrate, and the substrate 103 is formed with an absorption site capable of selecting absorbing DMA upon a semiconductor light lithography step. More specifically, the substrate 103 includes reaction portions in a matrix manner and in a regular manner with a regular interval upon a semiconductor light lithography step. The absorption site is bonded with, more specifically, aminosilane, polylysine, or epoxy capable of selectively being bonded with DNA. Alternatively, surface processing capable of selectively being bonded with DNA is applied in the absorption site.
According to this configuration, the size of the flow chip can be reduced. The specific size of the flow chip 100 according to the present embodiment will be explained later. It should be noted that
As illustrated in
As illustrated in
A claw unit 206 is provided at the position of the insertion port 205 of the flow chip cartridge 201. As illustrated in
Subsequently, a positional relationship between an object lens and a flow chip having a fluid channel hole on a substrate back surface will be explained. First, a conventional configuration will be explained.
The cover glass 1001 of the flow chip 1000 includes an inlet port 1002 and an outlet port 1003 for reagent. A fluid channel is formed in the flow chip 1000. The inlet port 1002 and the outlet port 1003 are connected to tubes 1101, 1102, respectively. The silicon substrate 1006 of the flow chip 1000 is processed in surface processing to be able to selectively fix DNA upon a semiconductor lithography step. On the substrate 1006, DNBs 1008 which are amplification products of DNA can be disposed in a selectively manner and in a matrix manner with a pitch of 600 nm. The DNB 1008 are obtained by amplifying a target DNA in accordance with rolling circle amplification method, and has a spherical shape having a diameter of 300 nm.
Although not shown in the drawings, the flow chip 1000 is disposed on the heat block, and the temperature is adjusted in a range between 10 to 80 degrees Celsius. Further, a reagent is supplied via the tube 1101 to the inlet port 1002 of the cover glass 1001 of the flow chip 1000, and thereafter, the reagent is discharged through the outlet port 1003 via the tube 1102. Although not shown in the drawing, the heat block for holding the flow chip 1000 is fixed on the XY stage. Therefore, the flow chip 1000 and the tubes 1101, 1102 move relatively with respect to the object lens 1103. However, the tubes 1101, 1102 and the object lens 1103 may mechanically interfere according to driving of the XY stage. Therefore, the range in which the XY stage can be drive is limited to the range in which the tubes 1101, 1102 and the object lens 1103 interfere with each other. More specifically, as illustrated in
In this case, in
In
Subsequently, the detailed shape of the heat block for fixing the flow chip 100 having the fluid channel hole on the substrate back surface will be explained.
A bar code label is adhered to the flow chip cartridge 201 of
The flow chip cartridge 201 holding the flow chip 100 is fixed to a temperature adjustment unit 401. The temperature adjustment unit 401 has a role of fixing the flow chip cartridge 201 and performing temperature control of the reagent in the fluid channel of the flow chip 100. The temperature adjustment unit 401 includes at least a heat block 402, a Peltier device 403, and a heat sink 404. The flow chip cartridge 201 is fixed to the neat block 402. The Peltier device 403 is disposed under the heat block 402.
Temperature sensors 405, 406 are inserted into the heat block 402 to monitor the temperature of the heat block 402. With the temperature sensors 405, 406, PID control is performed to a predetermined temperature, so that the temperature of the heat block 402 can be caused to be at the predetermined temperature. With this configuration, the reagent supplied into the flow chip 100 at the predetermined temperature within a range of 10 to 80 degrees Celsius can be caused to be at the temperature adjustment.
In order to discharge the heat generated by the Peltier device 403, the heat sink 404 is disposed under the Peltier device 403. A fan, not shown, is used to below air to the heat sink 404, so that the heat is discharged from the heat sink 404. Accordingly, the heat generated by the Peltier device 403 is swiftly discharged, and a temperature difference ΔT between the front and the back of the Peltier device 403 can be reduced. This has an effect of improving the heat transfer efficiency possessed by the Peltier device 403, and as a result, a high ramp rate can be realized. As illustrated in
The heat block 402 according to the present embodiment is provided with fixing pins 423, 424 at the positions of the first hole 209 and the second hole 210 of the flow chip cartridge 201, and the fixing pins 423, 424 are attached to the heat block 402 according to a method such as press fitting. Therefore, when the flow chip cartridge 201 is fixed to the heat block 402, the fixing pins 423, 424 facilitate the positioning of the flow chip cartridge 201. The present embodiment illustrates a configuration for fixing the flow chip cartridge 201 for holding the flow chip 100 to the temperature adjustment unit 401, but the present embodiment is not limited to this example. For example, depending on the type of the reagent, the temperature adjustment unit may not be necessary. Therefore, in such case, instead of the temperature adjustment unit 401, a fixing member for fixing the flow chip cartridge 201 may be provided. This fixing member may have a fixing pin and the like just like what has been described above.
Subsequently, a fixing method for fixing the flow chip 100 having the inlet port 105 and the outlet port 106 of the reagent on the substrate 103 to the neat block will be explained.
The Peltier device 403 is disposed immediately under the heat block 402, and further, the heat sink 404 is disposed below the Peltier device 403. In the example of
The flow chip cartridge 201 is pressurized in the lower direction by flow chip clamps 503, 504, so that the flow chip 100 is in close contact with the heat block 402. Accordingly, the flow chip 100 is brought into close contact with the heat block 402, and a preferable temperature control can be performed with the temperature adjustment unit 401. Since
Subsequently, a fixing method of a flow chip using a flow chip cover will be explained.
The notch unit of the heat block 402 is provided with resin members 501, 502 formed with fluid channels. The flow chip 100 having the inlet port 105 and the outlet port 106 on the substrate 103 is disposed on the heat block 402, so that the fluid channels are formed. O-rings are provided on the inlet port and the outlet port of the resin members 501, 502, and the flow chip 100 is pressurized from the upper side, so that the fluid channels that do not cause any liquid leakage can be formed. As described above, the heat block 402 is provided with the fixing pins 423, 424. As illustrated in
As illustrated in
In
As described above, the drivable area 801 of the object lens schematically illustrates a range in which the object lens moves relatively with respect to the flow chip 100 when the XY stage is driven. When the peripheral portion of the flow chip 100 is explained, the flow chip clamps 605, 606, 607, 608 are disposed on the upper surface of the flow chip 100, and the heat block 402 and fluid channel connection units (the connection units with the tubes 301, 302) are disposed on the lower surface of the flow chip 100. As illustrated in
The flow chip 100 and a structure for holding the flow chip 100 (the flow chip cartridge 201 and the like) is held on an XY stage (drive mechanism) 910. The XY stage 910 moves the flow chip 100 in a horizontal direction (XY direction) with respect to the object lens 930. The object lens 930 is fixed on a Z stage 919, and can move up and down in order to focus on the micro reaction field fixed to the flow chip 100. The object lens 930 is usually air gap, but it may also be possible to employ a method for filling pure water between the flow chip 100 and the object lens 930.
Reagents such as enzyme, four types of fluorescent reagents, buffer, nucleotide, cleaning fluid, and the like are disposed on a reagent cartridge 902. The reagent cartridge 902 in installed on the reagent rack 901, and is cooled to 4 degrees Celsius. A Peltier device 905 cools a heat block 904, and a fan 906 blow air in the reagent rack 901 to the heat block 904. The cooled air is circulated in the reagent rack 901, and the reagent 903 is indirectly cooled to 4 degrees Celsius.
Subsequently, fluid supply means for supplying reagent held on the reagent cartridge 902 to the inlet port 105 of the flow chip 100 and discharging the reagent from the outlet port 106 will be explained. The fluid supply means includes at least one syringe and multiple valves. The switch valve 907 can switch the fluid channel of the reagent held on the reagent cartridge 902. Accordingly, any given reagent can be introduced to the fluid channel. After the fluid channel is formed, the reagent passes through the fluid channel 908, and the reagent is supplied to the flow chip 100 holding the micro reaction field. Suction is performed by driving of a syringe 914 disposed on a downstream fluid channel 911. On the fluid channel 911, two two way valves 912, 913 are disposed. When the reagent is sucked, the syringe 914 is driven while the two way valve 912 is caused to be in an open state, and the two way valve 913 is caused to be in a closed state. In a case where reagent is supplied to a waste fluid tank 941, the syringe 914 is driven while the two way valve 912 is caused to be in a closed state, and the two way valve 913 is caused to be in an open state. With this operation, the supply of multiple reagents can be done with a single syringe 914.
The reagent having become waste fluid is passed to the waste fluid tank 941. In a case where there is no waste fluid tank 941, the waste fluid is spilled into the device, and there occurs a problem in that an electric shock, rust of the device, and occurrence of a foul smell, and the like. In order to avoid this, it is always necessary to arrange the waste fluid tank 941 in the device, and for this purpose, a micro photo sensor 942 for monitoring whether there is a waste fluid tank 941 or not is installed. In a case where the waste fluid leaks, a liquid reception tray 943 is installed under the waste fluid tank 941.
Elongation reaction of a DNA strand is performed by causing reaction of four types of nucleotides and polymerases labelled with different fluorochrome on the flow chip. The nucleotides are FAM-dCTP, Cy3-dATP, Texas Red-dGTP, and Cy5-dTsTP. The concentration of each nucleotide is 200 nM. The salt concentration, the magnesium concentration, and pH of the reaction liquid are optimized so that the elongation reaction is performed efficiently. The reaction solution includes polymerase, and a single base of fluorescent nucleotide complementary to the DNA fragment is retrieved. The reason why no elongation occurs in the second base is that a substance blocking elongation of the pigment of the second base is bonded with the fluorochrome of the first base. After the first base is retrieved, floating fluorescent nucleotide is removed by cleaning, and thereafter, fluorescent measurement is performed. In order to perform reaction of the minimum unit thereafter, a step of cleaving fluorochrome from the base with a dissociation solution and a step of cleaving an elongation blocking substance are required after the fluorescent measurement. With this step, a subsequent base elongation reaction can be continued successively. The fluorescent nucleotide is supplied into the flow cell again, and the reaction is repeated, so that a successive sequence is enabled. The reaction method employed in the present embodiment is called Sequence By Synthesis (SBS).
The optical detection system is arranged at the side of the cover glass 101 of the flow chip 100. In the following embodiment, the optical detection system will be explained in such a manner that the optical detection system is an incident-light fluorescence microscope, and includes LEDs, an optical filter, and a two-dimensional camera. Two LEDs 916, 917 are light sources for exciting fluorochrome. The center wavelengths of the LEDs 916 and 917 are 490 nm, 595 nm, respectively. The LED 916 is used for emission of excitation light of FAM-dCTP, Cy3-dATP, and the LED 917 is used for emission of excitation light of Texas Red-dGTP, Cy5-dTsTP. The dichroic mirror 951 aligns the light from the LEDs 916, 917 onto the same optical axis. Further, the excitation light is caused by the dichroic mirror 952 to be incident on the pupil plane of the object lens 930. The excitation light is emitted onto the fluorochrome retrieved into the micro reaction field in the flow chip 100 via the object lens 930, and the fluorochrome emits fluorescence. Apart of fluorescence emitted isotopically is collected by the object lens 930.
The light having passed through the object lens 930 is made into parallel light, and goes straight to the dichroic mirror 953 to be divided. The dichroic mirror 953 has gentle reflection characteristics for fluorescent wavelength areas in four colors. Therefore, on the light reception surfaces of CMOS cameras 922, 924, fluorescence intensity ratios of the bright spots emitted from the reaction fields on the flow chip 100 can be calculated. When the ratios on the imaging surface between two CMOS cameras 922, 924 are derived, it is possible to determine which of the four colors the light emission point belongs to. It should be noted that the parallel lights divided by the dichroic mirror 953 pass through emission filters 920, 925, respectively, and thereafter, the parallel lights are condensed by tube lenses 921, 923, and images are formed on the light reception surfaces of the CMOS cameras 922, 924.
According to the above configuration, the reagent is supplied into the flow chip 100, and with the temperature adjustment, the fluorescent nucleotide is caused to be retrieved, base by base, with polymerase on the micro reaction field, and elongation reaction is performed. The detection of the retrieved fluorochrome is recognized as an image, and this is applied to an adjacent panel, so that a large amount of base sequence information can be obtained. Thereafter, the fluorochrome is cleaved with a cleavage reagent, and the inside of the flow chip 100 is cleaned with a cleaning fluid, and thereafter, reagent including fluorescent nucleotide and polymerase is supplied again into the flow chip 100. These operations are performed for the required base length, so that base sequence analysis of DNA can be obtained.
In this device, the reaction reagent can be freely supplied in the flow chip 100 by driving the syringe 914 in the fluid channel forward direction and backward direction. At this occasion, the fluid channel is connected to the reagent tube filled with air by the switch valve 907. More specifically, the reagent in the flow chip 100 can be swung back and forth in the fluid channel. Accordingly, this can increase the collision reaction frequency of reagent molecules and DNBs fixed on the substrate surface in the flow chip 100, and can improve the reaction efficiency. Therefore, the reaction time can be shortened. Further, in this device, the DNB which is a sample is directly supplied within the device to the flow chip 100, and can be fixed. Accordingly, the fixing processing for fixing the DNB to the flow chip, which is performed outside of the device as a preprocessing in the past, can also be reduced.
In the above explanation, the reaction method of SBS has been explained, but another reaction method may be employed. For example, the supplied reagent includes oligomer modified by multiple fluorochromes, ligase for adding oligomer to DNA base, cleaning reagent, image obtaining reagent, and protecting group dissociation reagent, and the reaction method may be a sequence by ligation (SBL).
According to the embodiment of the present invention explained above, on the surface (the substrate 103) of the flow chip 100 at the opposite side to the surface where the object lens 303 is disposed with respect to the flow chip 100, the inlet port 105 and the outlet port 106 of the reagent of the flow chip 100 is provided. The shape of the heat block 402 for performing the temperature adjustment of the flow chip 100 is optimized, and is optimized into a heat block shape that enables the reagent to be injected and discharged from the direction of the surface where the temperature of the flow chip 100 is adjusted. Accordingly, a mechanical interference between the object lens 303 and the fluid channel connection unit of the flow chip 100 can be avoided. As a result, the size of the flow chip 100 can be reduced, and the cost can be reduced.
The present invention is not limited to the above embodiment, and includes various modifications. The above embodiment has been explained in details in order to explain the present invention in an easy to understand manner, and is not necessarily limited to those having all of the above configurations explained above. Some of the elements of any given embodiment may be replaced with elements of another embodiment. Elements of another embodiment may be added to elements of any given embodiment. With regard to some of the elements of each embodiment, other elements can be added, deleted, or replaced.
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421: installation unit
Number | Date | Country | Kind |
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2014-077095 | Apr 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/057080 | 3/11/2015 | WO | 00 |