JP2023000748A - Base sequence detection chip, base sequence detection cartridge, and chip manufacturing method - Google Patents

Abstract

To improve yield.SOLUTION: A base sequence detection chip according to the present embodiment includes a detection electrode, a current path, and a probe. The detection electrode has a plurality of partial electrodes. The current path is connected at one side with each of the plurality of partial electrodes and is connected at the other side with a current detection system. The probe has a base sequence that is fixed onto the detection electrode and to detect a target base sequence.SELECTED DRAWING: Figure 3

Description

Embodiments disclosed in this specification and drawings relate to base sequence detection chips, base sequence detection cartridges, and chip manufacturing methods.

As a method for detecting base sequences such as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), there is a current detection method. In the current detection method, a double-stranded structure is formed by a probe reagent, which is called a DNA chip, which is the target DNA applied on the electrode of the substrate, and the target DNA in the sample, and the probe specifically adsorbs to the double-stranded structure. By inserting a reducing agent, an oxidation-reduction current flows when a voltage is applied, and if an oxidation-reduction current equal to or higher than the threshold value can be detected, the presence of the target DNA in the sample can be detected.
The magnitude of the oxidation-reduction current value during detection is determined by the amount of the target DNA probe immobilized on the electrode, the length of the base sequence of the probe, and the like. Therefore, the redox current increases or decreases depending on the concentration of the DNA probe in the applied reagent, the surface condition of the electrode that affects the immobilization of the DNA probe on the electrode, the drying conditions after application, and the like. If the increase/decrease width is larger or smaller than the threshold, there is a problem that the inspection becomes invalid.

Japanese Patent Publication No. 2008-525822 International Publication No. 2016/047561

One of the problems addressed by the embodiments disclosed in the specification and drawings is to improve yield. However, the problems to be solved by the embodiments disclosed in this specification and drawings are not limited to the above problems. A problem corresponding to each effect of each configuration shown in the embodiments described later can be positioned as another problem.

A base sequence detection chip according to this embodiment includes a detection electrode, a current path, and a probe. The detection electrode has a plurality of partial electrodes. One of the current paths is connected to each of the plurality of partial electrodes, and the other is connected to a current detection system. The probe has a nucleotide sequence for detecting a target nucleotide sequence immobilized on the detection electrode.

FIG. 1 is a diagram showing the concept of DNA complementary binding assumed in this embodiment. FIG. 2 is a conceptual diagram showing a DNA current detection method. FIG. 3 is a diagram showing a first example of a base sequence detection chip. FIG. 4 is a diagram showing a first cutting example of a current path in the first example of the base sequence detection chip. FIG. 5 is a diagram showing a second cut example of the current path in the first example of the base sequence detection chip. FIG. 6 is a diagram showing a second example of a base sequence detection chip. FIG. 7 is a diagram showing a first cutting example of a current path in a second example of a base sequence detection chip. FIG. 8 is a diagram showing a second cut example of the current path in the second example of the base sequence detection chip. FIG. 9 is a top view showing a configuration example of a base sequence detection chip in which a plurality of detection electrode groups are arranged. FIG. 10 is a bottom view showing a configuration example of a base sequence detection chip in which a plurality of detection electrode groups are arranged. FIG. 11 is a side view of a configuration example of a base sequence detection chip in which a plurality of detection electrode groups are arranged, viewed from the y-axis direction. FIG. 12 is a side view of a configuration example of a base sequence detection chip in which a plurality of detection electrode groups are arranged, viewed from the x-axis direction. FIG. 13 is a flow chart showing an example of a chip manufacturing method for a base sequence detection chip. FIG. 14 is a perspective view showing the outline of the base sequence detection cartridge. FIG. 15 is a perspective view showing the configuration of a base sequence detection cartridge. FIG. 16 is a top view of a nucleotide sequence detection cartridge.

A base sequence detection chip, base sequence detection cartridge, and chip manufacturing method according to the present embodiment will be described below with reference to the drawings. In the following embodiments, it is assumed that parts denoted by the same reference numerals perform the same operations, and overlapping descriptions will be omitted as appropriate.

The concept of base sequence detection by the current detection method assumed in this embodiment will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a diagram showing the concept of complementary binding of DNA (Deoxyribonucleic Acid). DNA is a double-stranded nucleic acid composed of four bases, A (adenine), T (thymine), G (guanine) and C (cytosine). RNA (Ribonucleic Acid) is a single-stranded or double-stranded nucleic acid composed of four bases: A (adenine), U (uracil), G (guanine) and C (cytosine). In the following, the detection of DNA will be described as an example, but RNA may also be used, and any nucleic acid having a specific target base sequence can be similarly applied. In double-stranded DNA, specific combinations of bases, such as A (adenine) and T (thymine), G (guanine) and C (cytosine), complementarily bind.

Next, FIG. 2 shows the concept of DNA sequence detection by the current detection method.
In detecting a DNA sequence, a single-stranded DNA probe 11 obtained by synthesizing DNA having a known sequence is immobilized on an electrode on a substrate. The target DNA 12 to be inspected is also treated to be single-stranded and reacted with the DNA probe 11 immobilized on the electrode. If the sequence of the target DNA 12 is complementary to the sequence of the DNA probe 11, they will bind to each other and become double-stranded. Thus, the complementary binding of the single-stranded DNA probe 11 and the single-stranded target DNA 12 to form a double strand is called hybridization.
Specifically, if the DNA probe 11 has the sequence "GTCAAG" and the target DNA 12 in the specimen has the sequence "CAGTTC", the base sequences are complementary, so that they bind to each other to form a double strand. .

Subsequently, a reducing agent 13 that specifically adsorbs to the double strand is inserted onto the electrode. When the reducing agent 13 is inserted, the reducing agent 13 binds to the hybridized DNA probe 11 . When a voltage is applied to the electrodes with the reducing agent 13 bound thereto, an oxidation-reduction current (hereinafter simply referred to as current) is generated in the electrodes. The current value measured at the position where the non-hybridized DNA probe 11 is fixed is considerably higher than the current value measured at the position where the hybridized DNA probe 11 is fixed. small. Therefore, the presence or absence of hybridization can be easily determined by the magnitude of the current. That is, when a current exceeding the threshold value is generated by hybridization, the target DNA 12 to be tested is detected.

A first example of the base sequence detection chip according to this embodiment will be described with reference to the conceptual diagram of FIG.
The base sequence detection chip shown in FIG. 3 shows detection electrodes 2 provided on a substrate (not shown) and current paths 3 corresponding to each detection electrode 2 . Here, an example is shown in which three sets of detection electrodes 2 and corresponding current paths 3 are arranged in parallel. It should be noted that the present invention is not limited to this, and may include one or two sets, or a large number of sets, as long as the circuit pattern for the current path 3 permits.

The substrate is made of glass or silicon, for example.
The detection electrode 2 is made of a metal such as gold, is coated with a probe reagent, and is immobilized with a DNA probe. The sensing electrode 2 is divided into multiple regions. In other words, it has a plurality of partial electrodes. Here, it is assumed that the area is divided into three regions each different and has three partial electrodes. The first partial electrode 21 with the largest area occupies 70% of the area of the entire detection electrode 2 . The second partial electrode 22 with the second largest area occupies 20 percent of the total area of the detection electrode 2 . The third partial electrode 23 with the smallest area occupies 10% of the area of the entire detection electrode 2 .

Each of the first partial electrode 21, the second partial electrode 22 and the third partial electrode 23 is spaced apart. It should be noted that the partial electrodes are not limited to being physically separated as shown in FIG. 3, and may be formed electrically independently of each other.
The substrate has a dropping area 25 where a probe reagent containing a probe having a base sequence for detecting a symmetrical base sequence is supposed to be dropped. A first partial electrode 21 , a second partial electrode 22 and a third partial electrode 23 are provided in the dropping area 25 . DNA probes are fixed to each of the first partial electrode 21 , the second partial electrode 22 and the third partial electrode 23 by drying the probe reagent dropped onto the dropping area 25 .

The current path 3 is formed of a conductor such as a metal, one of which is connected to each partial electrode, the other of which is connected to a detection system, and is arranged so as to be disconnectable from each partial electrode. Specifically, the first current path 31 is connected to the first partial electrode 21, the second current path 32 is connected to the second partial electrode 22, and the third current path 33 is connected to the third partial electrode. Further, the first current path 31, the second current path 32 and the third current path 33 are connected in parallel and connected to the detection system. That is, the current value detected by each detection electrode 2 is the sum of the currents detected by the first partial electrode 21, the second partial electrode 22 and the third partial electrode 23, respectively.

Next, FIG. 4 shows a first cutting example of the current path in the first example of the base sequence detection chip.
FIG. 4 is a conceptual diagram when the second current path 32 is cut. The second current path 32 connected to the second partial electrode 22 corresponding to 20% of the area of the sensing electrode 2 is cut. As a cutting method, for example, a router, a laser, or the like may be used to cut the current path, or a switch for switching the connection may be used. It should be noted that the method of electrically cutting the current path is not limited to the method of physically cutting the current path. A DNA probe immobilized on the second partial electrode 22 whose path has been cut does not participate in current detection. Therefore, the remaining 80% of the area of the detection electrode 2, that is, the current from the first partial electrode 21 and the third partial electrode 23 is detected by the detection system. can be done.

Next, FIG. 5 shows a second example of cutting the current path in the first example of the base sequence detection chip.
FIG. 5 is a conceptual diagram when the second current path 32 and the third current path 33 are cut.
A second current path 32 connected to a second partial electrode 22 corresponding to 20% of the area of the detection electrode 2 and a third current connected to a third partial electrode 23 corresponding to 10% of the area of the detection electrode 2. and the paths 33 are cut off. As a result, DNA probes corresponding to 30% of the detection electrode area fixed to the second partial electrode 22 and the third partial electrode 23 whose paths have been cut do not participate in current detection. Therefore, the detection system detects the remaining 70% of the area of the detection electrode, that is, the current from only the first partial electrode 21, so that the current value can be reduced by approximately 30% from that before cutting. By connecting the current paths in parallel in this manner, the amount of decrease in the current value can be finely adjusted.
In the present embodiment, since the area of the first partial electrode 21 connected to the first current path 31 is larger than that of the other partial electrodes, the current from the first partial electrode 21 that occupies most of the current Although it is difficult to assume that is not detected, the first current path 31 may of course be disconnected.

Next, a second example of the base sequence detection chip according to this embodiment will be described with reference to FIG.
In the first example, the current paths connected to each partial electrode are connected in parallel, but in the second example, the current paths are connected in series. The shape and arrangement of the detection electrodes 2 are the same as in the first embodiment.

The first current path 31 has one end connected to the detection system and the other end connected to the first partial electrode 21 . The second current path 32 has one end connected to the first partial electrode 21 and the other end connected to the second partial electrode 22 . The third current path 33 has one end connected to the second partial electrode 22 and the other end connected to the third partial electrode 23 . That is, the first partial electrode 21 to the third partial electrode 23 are connected in series. Each current path is arranged so as to be disconnectable from a plurality of partial electrodes, as in the case of the first example shown in FIG.

Next, FIG. 7 shows a first cutting example of the current path in the second example of the base sequence detection chip. FIG. 7 is a conceptual diagram when the third current path 33 is cut.
The third current path 33 connected to the third partial electrode 23 corresponding to 10% of the area of the sensing electrode 2 is cut. As a result, as in the case of FIG. 4, the DNA probe immobilized on the third partial electrode 23 whose path has been cut does not participate in current detection. Therefore, the remaining 90% of the area of the detection electrode, that is, the current from the first partial electrode 21 and the second partial electrode 22 is detected by the detection system, so that the current value can be reduced by approximately 10% compared to before cutting. can.

Next, FIG. 8 shows a second example of cutting the current path in the second example of the base sequence detection chip. FIG. 8 is a conceptual diagram when the second current path 32 and the third current path 33 are cut.
As shown in FIG. 8, in the case of a series connection, by cutting the second current path 32 connected to the second partial electrode 22 corresponding to 20% of the area of the detection electrode 2, the second partial electrode 22 and the third partial electrode 23 are not involved in current detection. Therefore, in the case of the parallel connection as in the first embodiment, the second current path 32 and the third current path 33 are cut off, respectively, so the disconnection process is required twice. can reduce the current value by about 30% compared to before cutting. By connecting the current paths in series in this way, it is possible to increase the amount of decrease in the current value per location and reduce the number of disconnections compared to the case of parallel connection.

Next, a configuration example of the base sequence detection chip 100 according to this embodiment will be described with reference to FIGS. 9 to 12. FIG.
FIG. 9 is a top view of a base sequence detection chip 100 in which a plurality of detection electrode groups 91 each including the three detection electrodes 2 described above are arranged. The structures shown in FIGS. 9 to 12 can also be applied when one detection electrode group 91 is arranged.

In the example of FIG. 9 , a plurality of detection electrode groups 91 are arranged in two rows on the substrate 1 . Each detection electrode 2 included in the detection electrode group 91 is electrically connected to the corresponding detection terminal 92 via the current path 3 . The current generated by the detection electrode 2 is taken out as an electric signal to the detection system outside the base sequence detection chip 100 through the detection terminal 92 . Here, when the current paths 3 are connected in parallel as shown in FIG. When the current paths 3 are connected in series as shown in FIG. 6, the first current path 31 is connected to the detection terminal 92 .
Each detection electrode 2 is connected to a test terminal 4 for continuity test via a circuit pattern. The test terminal 4 is arranged for each partial electrode of the detection electrodes so that a continuity test can be performed for each partial electrode.
In the base sequence detection chip 100, the probe reagent is dropped onto the dropping region 25 and dried to allow DNA probes to be applied to each of the detection electrodes 2, that is, the first partial electrode 21, the second partial electrode 22 and the third partial electrode 23. is fixed.

Using three detection electrodes 2, the same measurement object (target DNA 12 in the example of FIG. 2) can be detected. Moreover, in order to detect the same object to be measured, an electrode pad 93 may be arranged for collectively taking out the electric signals respectively generated by the three detection electrodes 2 . The presence or absence of the object to be measured is detected based on the outputs of the plurality of detection electrodes. Although an example in which the same object to be measured is detected by the three detection electrodes 2 is shown here, the same object to be measured is not limited to this. One electrode pad 93 may be arranged for a plurality of detection electrodes 2 for detecting . Further, if the detection system side can recognize and process a plurality of detection electrodes 2 for detecting the same object to be measured, the electrode pads 93 need not be provided.

Although not shown in FIG. 9, it is assumed that the base sequence detection chip according to the present embodiment further includes a reference electrode and a counter electrode, and detects current by a three-electrode method using the detection electrode as a working electrode. do. Specifically, we envision a potentiostat in which the voltage of the counter electrode is varied such that the voltage of the reference electrode relative to the working electrode is set to a certain characteristic, and the oxidation current is electrochemically measured.
When target DNA is detected, hybridization occurs by flowing a reagent containing the target DNA along the flow path formed on the detection electrode group 91 .

As a more specific method, for example, a configuration of a base sequence detection chip and a current detection method as disclosed in Japanese Unexamined Patent Application Publication No. 2016-61769 may be employed.

FIG. 10 is a bottom view of the base sequence detection chip 100. FIG. 10 to 12, for convenience of explanation, the second current path 32 is indicated by a solid line and the third current path 33 is indicated by a broken line, but they are actually formed by circuit patterns.
As shown in FIG. 10, the circuit is arranged such that the second current paths 32 connected to the respective detection electrodes 2 gather on the left side in the x-axis direction from the detection electrode group 91 arranged on the upper surface of the substrate toward the lower surface of the substrate. pattern is placed. On the other hand, the circuit pattern is arranged so that the third current paths 33 connected to the detection electrodes 2 are gathered on the right side in the x-axis direction. By arranging the circuit pattern by routing the current paths in this manner, the current paths of the respective electrodes can be cut together. For example, when cutting the second current path 32, the second current path 32 is cut at once for each row of the detection electrode group 91 by cutting the part where the second current path 32 gathers in parallel with the x-axis. can.
If the first current path 31 is also cuttable, the circuit patterns may be arranged toward the lower surface of the substrate, for example, in the central portion in the same manner as the second current path 32 and the third current path 33. .

Next, FIG. 11 shows a side view of the base sequence detection chip 100 viewed from the y-axis direction, and FIG. 12 shows a side view of the base sequence detection chip 100 viewed from the x-axis direction.
As shown in FIGS. 11 and 12, the second current path 32 is gathered on the left side of the x-axis, and the third current path 33 is gathered on the right side of the x-axis. are arranged differently within the substrate 1 . By arranging in this way, for example, when cutting along the x-axis direction at a depth (height) in the z-axis direction at which only the third current path 33 is cut, the second current path in the x-axis direction may be erroneously cut. Even if it is cut to the position 32, the depth (height) of the second current path 32 is not actually reached, so the second current path 32 does not have to be cut. Therefore, erroneous cutting can be prevented. The collective positions of the second current path 32 and the third current path 33 may be the same height in the z-axis direction.

Next, an example of a chip manufacturing method for the base sequence detection chip 100 will be described with reference to the flow chart of FIG. Here, it is assumed that the arrangement of the detection electrodes 2 and current paths 3 of the base sequence detection chip shown in FIG. 3 or 6 has already been completed, and the structure of the base sequence detection chip shown in FIG. 9 has been completed. Each step shown in FIG. 13 may be performed, for example, by a base sequence detection cartridge that detects target DNA using a base sequence detection chip.

In step S11, each detection electrode 2 of the base sequence detection chip 100 is coated with a probe reagent.
In step S12, the probe reagent is dried. Thereby, the DNA probe is immobilized on each partial electrode. After that, in a sampling inspection, a plurality of base sequence detection chips are selected for inspection.

In step S13, a sample containing target DNA is allowed to flow through the detection electrode group 91 along the flow path for each of the plurality of selected base sequence detection chips 100, thereby causing hybridization.
In step S14, a reducing agent is inserted and the current value at each detection electrode 2 is measured.

In step S15, for each detection electrode 2, it is determined whether or not the measured current value is within the allowable range. If the measured current value is within the allowable range, the process is terminated, and if the measured current value is greater than the maximum value of the allowable range, the process proceeds to step S16.
In step S16, the difference between the current value and the maximum allowable range, that is, the excess current value is calculated.
In step S17, a current path to be cut is selected according to the difference. For example, if the excess current value that is the difference is within 10% of the maximum value of the allowable range, the current path connected to the partial electrode having the area ratio corresponding to the excess current value may be cut off. 3 current paths may be selected as paths to be cut. Note that the difference may not match the percentage of the current value that is reduced by cutting the current path, such as a value corresponding to 15% of the maximum value of the allowable range. In this case, the route to be cut may be selected so that the reduction rate is greater than the difference. For example, in the case of parallel connection, if the difference is a value corresponding to 15% of the maximum allowable range, the second current path 32 or the second current path 32 and the third current path 33 are selected as the path to be disconnected. .
In step S18, the selected current path is cut. This completes the base sequence detection chip for shipping. This completes the description of the flowchart shown in FIG.

In the example of FIG. 13, the sample and the reducing agent are actually inserted in the sampling inspection, the current value is measured, and it is determined whether or not to cut the current path, but the present invention is not limited to this. For example, when the pixel value of the image of the detection electrode 2 to which the probe reagent is applied is smaller than the threshold value in the image inspection, the pixel value becomes small due to the high concentration of the applied probe reagent. The current path may be cut assuming that it is greater than the allowable range. Specifically, the corresponding relationship between the excess current value, the current path to be cut, and the pixel value of the image of the detection electrode 2 is extracted in advance by the chip manufacturing method of FIG. When the pixel value of the image of the detection electrode 2 is smaller than the threshold value, it is determined that the current value is not within the allowable range. A current path to be cut may be selected.

Moreover, whether or not to cut the current path may be determined based on the characteristics of the DNA probe immobilized on the detection electrode. For example, if the base sequence of the DNA probe is long, it is expected that the observed current value will be large. Therefore, the correspondence between the length of the base sequence of the DNA probe and the current value is measured in advance. Based on this, the current path to be cleaved may be selected according to the length of the DNA probe immobilized on the detection electrode.

In the above-described embodiment, an example in which three partial electrodes having different area ratios are formed as the first partial electrode 21, the second partial electrode 22, and the third partial electrode 23 is shown. It is not limited to this, and may be divided into four or more partial electrodes each having a different area ratio. Alternatively, the areas may be divided so as to have the same area ratio without different area ratios. For example, when divided into five partial electrodes, each partial electrode may be formed to have the same area ratio, that is, 20% of the total area of the detection electrode.

Next, an example of a base sequence detection cartridge that mounts the base sequence detection chip according to the present embodiment and detects a base sequence to be measured will be described with reference to FIGS. 14 to 16. FIG.
FIG. 14 shows an external view of the nucleotide sequence detection cartridge. Base sequence detection cartridge 700 includes lower plate 710 , packing 720 , upper plate 730 , cover 740 and cap 750 . Packing 720 is inserted between lower plate 710 and upper plate 730 . A cover 740 is attached to the top plate 730 . Cap 750 is attached to cover 740 by a hinge. The lower plate 710, upper plate 730, cover 740 and cap 750 are made of transparent polycarbonate (PC), for example, and the packing 720 is made of transparent elastomer, for example.

Next, FIG. 15 shows the configuration of the nucleotide sequence detection cartridge 700. As shown in FIG. The lower plate 710 is provided with a bank 710a along its perimeter, the inner surface of which is lower than the bank 710a. An opening 710b is provided inside the bank 710a. A base sequence detection chip 100 is placed around the opening 710b, and a support portion 710b1 for supporting the base sequence detection chip 100 is provided. The support portion 710b1 is provided on the bottom side of the opening 710b so that the upper surface of the base sequence detection chip 500 is lower than the inner surface of the bank 710a when the base sequence detection chip 100 is placed on the support portion 710b1. be done. The packing 720 is arranged so as to cover the area inside the bank 710a.

FIG. 16 shows a top view of the base sequence detection cartridge 700 when the base sequence detection chip 100 is mounted. The inner side of the bank 710a of the lower plate 710 is provided with four depressions 710c1, 710c2, 710c3, 710c4 forming the syringe portion 710c. The depression 710c1 forms a tank together with the bulge of the packing 720, and a liquid containing, for example, the DNA of the specimen, that is, the sample is stored in this tank. The recess 710c2 forms a tank together with the swelling of the packing 720, in which for example cleaning liquid is stored. A reagent including, for example, an intercalating agent is stored in the recess 710c3. The depression 710c4 forms a tank together with the swelling of the packing 720, in which for example cleaning liquid is stored. Injection portions 710d1, 710d2, 710d3, and 710d4 for injecting liquid are provided on the inlet sides of the recesses 710c1, 710c2, 710c3, and 710c4, respectively. 710 c 2 , 710 c 3 , 710 c 4 are connected by grooves provided in the lower plate 710 as channels.

An air vent 710e1 is provided on the inlet side of the recess 710c1, an air vent 710e2 is provided on the outlet side of the recess 710c2, an air vent 710e3 is provided on the outlet side of the recess 710c3, and an air vent 710e4 is provided on the outlet side of the recess 710c4. It is

In addition, inside the bank 710a of the lower plate 710, a normally closed valve NCV provided on the outlet side of each of the depressions 710c1, 710c2, 710c3, and 710c4, an amplification channel 710f for amplifying DNA in the sample, A normally open valve NOV is provided at the inlet and outlet of the amplification channel 710f, and depressions 710g1 and 710g2 that serve as waste liquid tanks 711g1 and 711g2 are provided to retain the waste liquid in the base sequence detection cartridge. . Waste liquid tanks 711g1 and 711g2 are formed by recesses 710g1 and 710g2, packing 720, and upper plate 730. As shown in FIG.

Valve NCV is formed by lower plate 710 , packing 720 and cover 740 , and valve NOV is formed by lower plate 710 and packing 720 . The valve NCV is used to store reagents and the like in the syringe portion 710c. The valve NOV is used to close the channel so that reagents and the like do not move during DNA amplification.

A valve NCV provided on the outlet side of the depressions 710c1 and 710c2 is connected to a valve NOV provided on the inlet side of the amplification channel 710f through a channel formed in the lower plate 710. FIG. The valve NCV provided on the outlet side of the recesses 710c3 and 710c4 is connected to the inlet of the channel on the base sequence detection chip 100 formed with the packing 720 and the channel formed in the lower plate 710. A valve NOV provided on the outlet side of the amplification channel 710 f is connected to the inlet of the channel on the base sequence detection chip 100 formed with the packing 720 and the channel formed in the lower plate 710 . The outlet of the channel on the base sequence detection chip 100 formed with the packing 720 is connected to the recess 710 g 1 by the channel formed in the lower plate 710 .

As shown in FIG. 15, the packing 720 is provided with dome-shaped bulges protruding toward the upper plate 730 in regions corresponding to the dents 710c1, 710c2, 710c3, and 710c4. , 710c2, 710c3, 710c4 form the tank of the syringe portion 710c. Packing 720 has a tube structure in cross section as will be described later in the region where valve NCV and valve NOV are formed, and this tube structure and lower plate 710 form a flow path. The area of the lower plate 710 corresponding to this tubular structure is flat without grooves. In addition, the surface of the packing 720 covering the channel grooves formed in the lower plate is flat. A flow path is formed by the flat surface of the packing and the groove.

The packing 720 has openings in regions corresponding to the recesses 710g1 and 710g2, and openings corresponding to regions in which the terminals of the base sequence detection chip 100 are provided. Therefore, when the mounted base sequence detection chip 100 is the chip shown in FIG. 9, two openings are required.

Upper plate 730 is provided with a first opening in a region corresponding to the swelling of packing 720 . A rod extends from the DNA sequence detection controller (not shown) through this first opening and pushes the upper surface of the tank, that is, the upper surface of the swelling of the packing 720, thereby discharging the liquid from the tank into the channel. At this time, the valve NCV provided on the outlet side of the tank is opened. Further, the upper plate 730 is provided with a second opening corresponding to the region where the terminals of the base sequence detection chip 100 are provided. The area where the first opening is provided has a lower upper surface than the area where the second opening is provided. A cover 740 is attached to the region where the first opening is provided. Further, in the region where the first opening is provided, an opening is provided in the region corresponding to the valve NCV.

In the above-described embodiments, base sequence detection chips are assumed for the purpose of detecting nucleic acids. Chip structures and similar chip manufacturing methods can be used.

According to the present embodiment described above, when the current value from the detection electrode is not within the allowable range, the partial electrodes having the area ratio corresponding to the excess current value correspond to the excess current value exceeding the allowable range. Cut off the connected current path. As a result, for example, even if the current value is larger than the default value or the allowable range, even if the product is judged to be defective in the past, it can be shipped as a normal product by cutting the path after processing, reducing disposal loss. As a result, yield can be improved.

According to at least one embodiment described above, yield can be improved.

While several embodiments have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations of embodiments can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

REFERENCE SIGNS LIST 1 substrate 2 detection electrode 3 current path 4 test terminal 11 DNA probe 12 target DNA
13 reducing agent 21 first partial electrode 22 second partial electrode 23 third partial electrode 25 dropping area 31 first current path 32 second current path 33 third current path 91 detection electrode group 92 detection terminal 93 electrode pad 100 base sequence detection chip 710 lower plate 710a bank
710b opening 710b1 support part 710c syringe part 710d1, 710d2, 710d3, 710d4 injection part 710e1, 710e2, 710e3, 710e4 air vent 710f amplification channel 711g1, 711g2 waste liquid tank 720 packing 730 upper plate 740 cap cover 750

Claims (11)

a detection electrode having a plurality of partial electrodes;
a current path one of which is connected to each of the plurality of partial electrodes and the other of which is connected to a current detection system;
a probe having a base sequence for detecting a target base sequence immobilized on the detection electrode;
A base sequence detection chip comprising: 2. The base sequence detection chip according to claim 1, wherein said current path is connected to each partial electrode such that said plurality of partial electrodes are connected in parallel. 2. The base sequence detection chip according to claim 1, wherein said current path is connected to each partial electrode such that said plurality of partial electrodes are connected in series. 4. The base sequence detection chip according to any one of claims 1 to 3, wherein said current path is arranged so as to be disconnectable from said plurality of partial electrodes. 5. The base sequence detection chip according to any one of claims 1 to 4, further comprising a terminal connected to said other side of said current path for outputting an electric signal generated by said detection electrode to said detection system. . a plurality of said detection electrodes and corresponding said terminals;
6. The base sequence detection chip according to claim 5, further comprising an electrode pad for collectively taking out electrical signals respectively generated by a plurality of detection electrodes for detecting the same target. A plurality of the detection electrodes exist,
7. The base sequence detection chip according to any one of claims 1 to 6, wherein the presence or absence of a target is detected based on outputs from a plurality of detection electrodes. a base sequence detection chip according to any one of claims 1 to 7;
a storage unit for storing the base sequence detection chip;
a first tank for storing a sample containing a base sequence of interest;
a second tank for storing an intercalating agent for generating an oxidation-reduction current on the detection electrode of the base sequence detection chip;
a housing in which the storage section, the first tank, and the second tank are formed;
A base sequence detection cartridge comprising: 8. The base sequence detection chip according to any one of claims 1 to 7, wherein a determination step of determining whether a current value from a detection electrode formed of a plurality of partial electrodes is within an allowable range; ,
determining, if the current value is not within the allowable range, a partial electrode that does not allow current to be detected based on the current value;
a cutting step of cutting the current path connected to the determined partial electrode;
A chip manufacturing method comprising: 10. The chip manufacturing method according to claim 9, wherein said determination step determines that said current value is not within the allowable range when the length of the base sequence of the probe immobilized on said detection electrode is equal to or greater than a threshold. 10. The chip manufacturing method according to claim 9, wherein said determining step determines that said current value is not within an allowable range when a pixel value of said detection electrode image is smaller than a threshold value.

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