JP2004132720A - Hybridization detection part, sensor chip and hybridization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve hybridization efficiency by devising so that a detection nucleotide chain in the elongated state is immobilized on the entire reaction area. <P>SOLUTION: This hybridization detection part 1a is equipped with the reaction area R which is a place for hybridization between the detection nucleotide chain X and a target nucleotide chain having a base sequence which is complementary to the detection nucleotide chain, counter electrodes A, B disposed on the reaction area R, and a floating electrode C arranged in the scattered state between the counter electrodes A, B. This sensor chip where the detection part 1a is formed and this hybridization method performed on the detection part 1a are also provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique relating to a hybridization detection unit that can be suitably used for a sensor chip such as a DNA chip. More specifically, the present invention relates to a technique for improving hybridization efficiency by aligning and fixing nucleotide chains for detection of an extended state between scanning electrodes in a reaction region providing a hybridization field.
[0002]
[Prior art]
First, a general prior art of the present invention will be described below. At present, an integrated substrate for a bioassay called a DNA chip or a DNA microarray (hereinafter, collectively referred to as “DNA chip”) in which predetermined DNAs are finely arranged by microarray technology is used for gene mutation analysis, SNPs (single nucleotide). (Polymorphism) analysis, gene expression frequency analysis, etc., and have begun to be widely used in drug discovery, clinical diagnosis, pharmacogenomics, forensic medicine and other fields.
[0003]
This DNA chip has a large number of DNA oligo chains and cDNA (complementary DNA) integrated on a glass substrate or a silicon substrate, so that comprehensive analysis of intermolecular reactions such as hybridization can be performed. It is characterized by points.
[0004]
Briefly describing an example of an analysis method using a DNA chip, a DNA probe immobilized on a glass substrate or a silicon substrate is subjected to reverse transcription PCR reaction of mRNA extracted from cells, tissues, and the like to a fluorescent probe dNTP. This is a technique in which PCR amplification is carried out while the DNA is incorporated, hybridization is performed on the substrate, and fluorescence measurement is performed using a predetermined detector.
[0005]
Here, DNA chips can be classified into two types. The first type is one in which oligonucleotides are synthesized directly on a predetermined substrate by using a photolithography technique to which a semiconductor exposure technique is applied, and is typically obtained by Affymetrix (Affymetrix). (For example, refer to Patent Document 1). This type of chip has a high degree of integration, but has a limit in DNA synthesis on a substrate, and is about several tens of bases long.
[0006]
The second type is also referred to as a “Stanford method”, and is produced by dispensing and solidifying DNA prepared in advance on a substrate using a split pin ( For example, see Patent Document 2.) This type of chip has a lower degree of integration than the former, but has the advantage that a DNA fragment of about 1 kb can be immobilized.
[0007]
Subsequently, Non-Patent Document 1 discloses a technique (DNA immobilization methods) for fixing DNA to an electrode surface by the action of an electric field formed on floating electrodes arranged between opposed electrodes. I have.
[0008]
[Patent Document 1]
JP-T4-5055763
[Patent Document 2]
Japanese Patent Publication No. Hei 10-503841
[Non-patent document 1]
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 31, No. 3 MAY / JUNE 1995, P451
[0009]
[Problems to be solved by the invention]
First, in the conventional general DNA chip technology described above, a nucleotide chain for detection such as a DNA probe immobilized on a detection surface portion (spot portion) is entangled or rounded in a random coil shape due to Brownian motion. And the integration density was uneven on the detection surface. For this reason, steric hindrance occurs at the time of hybridization with the target nucleotide chain, so that the efficiency of hybridization is low, the reaction requires a long time, and furthermore, there is a possibility that false positive or false negative is shown. There was a basic technical problem that there was also.
[0010]
Therefore, in order to improve the efficiency of hybridization, it is necessary to fix DNA to a detection surface area (spot area) of an existing DNA chip with a linear structure that is expected to cause no steric hindrance. To achieve this, the DNA fixing technique disclosed in Non-Patent Document 1 is applied, a counter electrode and a floating electrode are arranged between the counter electrodes in the detection surface area of the DNA chip, and an electric field is applied to the sample solution. Immobilizing DNA on the surface of the floating electrode. However, in the DNA immobilization technique, since the floating electrode having the same length as the counter electrode is simply arranged between the counter electrodes, the amount and density of the non-uniform electric field formed on the surface of the floating electrode are low, and the DNA is immobilized. It was predicted that the hybridization efficiency would not be sufficiently improved because the amount of DNA used was not sufficient.
[0011]
Therefore, the present invention provides a hybrid between a detection nucleotide chain and a target nucleotide chain by devising an extended detection nucleotide chain in a reaction region providing a hybridization field so that the detection nucleotide chain can be fixed densely. The main purpose is to improve the hybridization efficiency.
[0012]
[Means for Solving the Problems]
In order to solve the above technical problems, first, in the present application, a reaction region serving as a place of hybridization between a nucleotide chain for detection and a target nucleotide chain having a base sequence complementary to the nucleotide chain for detection. A hybrid detection unit comprising: a counter electrode disposed in the reaction region; and a plurality of floating electrodes disposed so as to be interspersed between the counter electrodes.
[0013]
The arrangement configuration of the counter electrode is not particularly limited, but by adopting a configuration arranged in parallel with the reaction region, an electric field can be uniformly and densely formed over the entire reaction region sandwiched between the counter electrodes. Thereby, each nucleotide chain present in the reaction region can be extended in parallel along the line of electric force.
[0014]
When a high-frequency electric field of about 1 MV / m is applied to a nucleotide chain, the nucleotide chain is composed of a nucleotide chain consisting of a large number of polarization vectors composed of a negative charge of a nucleotide chain including phosphate ions and a positive charge of ionized hydrogen atoms. (Strand), which results in dielectric polarization, which results in the nucleotide molecules being stretched linearly parallel to the electric field.
[0015]
In the extended nucleotide chain, the bases do not overlap each other, so that the steric hindrance during the reaction is eliminated, and the probability of association (hydrogen bonding) between the complementary base sequences can be further increased. The hybridization reaction with the nucleotide chain to be performed is smoothly performed.
[0016]
In the present invention, the floating electrode plays a role of forming a large number of places in the reaction region where the lines of electric force are concentrated, and plays a role of fixing (terminals of) the nucleotide chain for detection to the places. By adopting a configuration in which the floating electrodes are arranged so as to be scattered in the reaction region between the opposed electrodes, a portion where the electric flux lines are concentrated can be uniformly and densely provided in the reaction region. . Further, the configuration in which the floating electrodes are scattered in the reaction region has an advantage that the nucleotide chain in the reaction region can move freely.
[0017]
Although the form of the floating electrode is not particularly limited, a floating electrode having an arc-shaped or polygonal surface shape, that is, a non-conductive electrode is preferred from the viewpoint that the electric field (lines of electric force) is easily concentrated and the nucleotide chain is easily fixed. A floating electrode having a shape capable of forming a uniform electric field can be employed. Further, it is preferable that the electrode surface of the floating electrode is formed to be narrower than the electrode surface of the counter electrode, since an electric field is easily concentrated on the electrode surface of the floating electrode, and an uneven electric field is easily formed. Furthermore, the surface of the floating electrode is subjected to a surface treatment capable of fixing the nucleotide chain for detection, whereby the operation of fixing the nucleotide chain for detection can be reliably performed.
[0018]
Next, the present application provides a sensor chip including at least the above-described hybridization detection unit. More specifically, a reaction region serving as a place of hybridization between a nucleotide chain for detection and a target nucleotide chain having a base sequence complementary to the nucleotide chain for detection, and a reaction region, which is disposed in the reaction region A counter electrode, and a plurality of floating electrodes disposed between the counter electrodes, and applying a voltage to the counter electrode to bring the detection nucleotide chain present in the reaction region into an extended state; A sensor chip capable of causing the detection nucleotide chain to undergo dielectrophoresis by a non-uniform electric field generated at a local surface portion of the counter electrode and the floating electrode, and to be fixed to the surface portion of the counter electrode and the floating electrode. I will provide a.
[0019]
According to this sensor chip, the detection nucleotide chain (in a form not suitable for hybridization), which is dropped and dispersed in the reaction region and entangled in a random coil shape by Brownian motion, is extended to form a high It is possible to adjust to a linear form which is easy to hybridize, and further, it is possible to fix the nucleotide chain for detection on the surface of the floating electrode in an extended state.
[0020]
Then, by further applying a voltage to the counter electrode, the target nucleotide chain present in the reaction region is extended, and the detection nucleotide chain immobilized on the surface portion of the counter electrode and the floating electrode. And hybridization. The electric field formed by the counter electrode in the sensor chip according to the present invention may be an alternating current.
[0021]
Further, the present application provides the following hybridization method. The method includes a reaction region serving as a place for hybridization between a nucleotide chain for detection and a target nucleotide chain having a base sequence complementary to the nucleotide chain for detection, and a counter electrode arranged in the reaction region. And a plurality of floating electrodes disposed between the opposed electrodes.
[0022]
Then, by applying a voltage to the counter electrode, the detection nucleotide chain present in the reaction region is set in an extended state, and the detection nucleotide chain in the extended state is formed on a local surface site of the counter electrode and the floating electrode. (1) performing dielectrophoresis with a non-uniform electric field generated at the surface of the floating electrode, and fixing the target nucleotide chain present in the reaction region by applying a voltage to the counter electrode. A step (second procedure) of bringing the nucleic acid into an extended state and hybridizing with the detection nucleotide chain in the extended state fixed to the surface portion of the floating electrode.
[0023]
In this method, an electric field is formed in the reaction region by applying a voltage to the counter electrode, thereby forming a non-uniform electric field on the surface of the floating electrode and the surface of the counter electrode disposed in the reaction region. Then, based on the effect of dielectrophoresis caused by the non-uniform electric field, first, a detection nucleotide chain is fixed to the surface portion of the electrode while extending.
[0024]
Subsequently, based on the same dielectrophoretic action as described above, while extending the target nucleotide chain that has been subsequently added to the reaction region, approached to the extended detection nucleotide chain fixed to the surface site, Hybridization can proceed more efficiently between linear nucleotide chains.
[0025]
The present invention described above provides a hybridization detection unit capable of efficiently detecting hybridization essential for gene mutation analysis, SNPs (single nucleotide polymorphism) analysis, gene expression frequency analysis, and the like, and a DNA including the detection unit. It has the technical significance of providing sensor chips such as chips to drug discovery, clinical diagnosis, pharmacogenomics, forensic medicine and other related industries.
[0026]
Here, the main technical terms in the present application are defined. In the present application, the term "nucleotide chain" means a polymer of a phosphate ester of a nucleoside in which a purine or pyrimidine base and a sugar are glycoside-linked, and an oligonucleotide including a DNA probe, a polynucleotide, a purine nucleotide and a pyrimidine nucleotide are polymerized. It widely includes DNA (full length or a fragment thereof), cDNA (cDNA probe) obtained by reverse transcription, RNA, polyamide nucleotide derivative (PNA), and the like.
[0027]
The “detection nucleotide chain” is a nucleotide chain directly or indirectly immobilized on the counter electrode or the floating electrode, and the “target nucleotide chain” is a base sequence complementary to the detection nucleotide chain. And may be labeled with a fluorescent substance or the like in some cases.
[0028]
“Hybridization” means a reaction of forming a complementary strand (duplex) between nucleotide chains having a complementary base sequence structure.
[0029]
The “reaction region” is a region that can provide a place for a hybridization reaction in a liquid phase. In this reaction region, in addition to the interaction between single-stranded nucleotides, that is, hybridization, a desired double-stranded nucleotide is formed from the nucleotide chain for detection, and the interaction between the double-stranded nucleotide and the peptide (or protein), Enzyme response reactions and other intermolecular interactions can also be performed. For example, when the double-stranded nucleotide is used, binding between a receptor molecule such as a hormone receptor as a transcription factor and a response element DNA portion can be analyzed.
[0030]
The “counter electrode” is at least a pair of electrodes facing each other in the reaction region, and plays a role of forming an electric field in the reaction region when a voltage is applied.
[0031]
“Floating electrode” means an isolated electrode that is conductive and is not connected to an external power supply.
[0032]
"Steric hindrance" means that the presence of a bulky substituent in the vicinity of a reaction center or the like in a molecule or the posture or steric structure (higher-order structure) of a reactive molecule makes it difficult to approach a molecule of a reaction partner. This means a phenomenon in which a desired reaction (in the present application, hybridization) hardly occurs.
[0033]
"Dielectrophoresis" is a phenomenon in which molecules are driven in a direction where the electric field is strong in a field where the electric field is not uniform, and even when an AC voltage is applied, the polarity of the polarization is reversed as the polarity of the applied voltage is reversed. A driving effect can be obtained in the same way as in the case of direct current (supervised by Teru Hayashi, "Micromachine and Material Technology (published by CMC)", pp. 37-46, Chapter 5, Cell and DNA manipulation).
[0034]
`` Sensor chip '' means at least a reaction region capable of detecting an interaction between substances on a substrate formed of quartz glass, a synthetic resin, or the like, and a device including at least a voltage applying unit for a counter electrode provided in the reaction region, A typical example is a DNA chip.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, FIG. 1 is a diagram illustrating a main configuration of a hybridization detection unit (hereinafter, simply referred to as a “detection unit”) and a sensor chip according to a first embodiment (reference numeral 1a) of the present invention.
[0036]
First, a reaction region R is provided in the detection unit 1a. The reaction region R is a storage region to which a sample solution containing a detection nucleotide chain indicated by a symbol X in FIG. 1 and a target nucleotide chain (not shown) is added, and which provides a hybridization reaction field. Or space.
[0037]
In the reaction region R, opposed electrodes A and B are arranged such that their end faces are parallel to each other, and are configured to be connectable to a power supply V shown in FIG. A plurality of floating electrodes C are arranged between the counter electrodes A and B so as to be scattered in the vertical and horizontal directions without being connected to the power supply V (see FIG. 1). Here, each floating electrode C has a circular shape. However, the shape is not particularly limited, and may be any shape such as a polygon or an ellipse that forms a non-uniform electric field.
[0038]
Further, by forming the electrode surface of each floating electrode C smaller than the electrode surfaces of the counter electrodes A and B, an electric field is easily concentrated on the electrode surface of the floating electrode C, and an uneven electric field is easily formed. Is preferred.
[0039]
FIG. 1 shows a state in which the switch S is turned on and a voltage is applied between the counter electrodes A and B, and the symbol X shown in the reaction region R is still rounded into a random coil shape. The symbol X ′ represents a detection nucleotide chain that is linearly extended and fixed to the electrode surface.
[0040]
Although not particularly shown, the detection unit 1a is provided in a narrow gap between substrates formed of synthetic resin such as quartz glass, silicon, polycarbonate, and polystyrene. In the detection unit 1a, a configuration is adopted in which the thickness of the opposing electrodes A and B and the depth (or width) of the reaction region R match, and in some cases, the electrodes A and B are sandwiched by a dielectric, This may increase the distance between the substrates and increase the capacity of the reaction region R (the same applies to a second embodiment described later).
[0041]
Here, FIG. 2 shows that the electric field L is formed in the reaction region R by turning on the illustrated switch S and applying a high-frequency voltage between the counter electrodes AB by the power source V in the detection unit 1a. The state is represented by showing lines of electric force. When a high-frequency voltage is applied between the electrodes A and B, a non-uniform electric field indicated by a reference numeral L is formed in the reaction region R.
[0042]
That is, when the voltages of the counter electrodes A and B are applied, a non-uniform electric field L in which the electric field is locally concentrated on the surface portions of the electrodes A and B and the floating electrodes C is formed (see FIG. 2). By the action of the non-uniform electric field L, it is possible to drive the detection nucleotide chains X, which are randomly dispersed in the reaction region R, while extending them in a direction along the non-uniform electric field L.
[0043]
Further, the detection nucleotide chain X is driven by the action of dielectrophoresis, and one end thereof is fixed to each of the surface portions of the electrodes A, B, and C having a strong electric field in an extended state. FIG. 1 and FIG. 2 show a state in which a detection-use nucleotide chain X ′ in an extended state is fixed to a surface portion of each of the electrodes A, B, and C.
[0044]
The condition of the electric field applied between the counter electrodes A and B is about 1 × 10 ⁶ v / m, about 1 MHz is suitable (Masao Washiz and Osamu Kurosawa: "Electrostatic Manipulation of DNA in Microfabricated Structures, No. 26, Act. .
[0045]
Subsequently, the target nucleotide chain that has been added later to the reaction region R is extended by the action of the non-uniform electric field L formed by the counter electrodes A and B in the same manner as the detection nucleotide chain X ′, It is attracted by dielectrophoresis to each surface portion of the strong electrodes A, B and C.
[0046]
The target nucleotide chain attracted to each surface site is not affected by steric hindrance between the target nucleotide chain X ′ in the extended state already immobilized on the surface site, and efficient hybridization is performed. proceed.
[0047]
The surfaces or ends of the counter electrodes A and B and each of the floating electrodes C may be subjected to a surface treatment so that the terminal portion of the nucleotide chain X ′ for detection is fixed by a reaction such as a coupling reaction. For example, in the case of an electrode surface that has been surface-treated with streptavidin, the electrode surface is suitable for fixing a terminal of a biotinylated nucleotide chain.
[0048]
Next, a configuration of a detection unit and a sensor chip according to a second embodiment (reference numeral 1b) according to the present invention will be described with reference to FIG.
[0049]
First, in the detecting section 1b, similarly to the above-described detecting section 1a, a reaction region R and opposing electrodes A and B are arranged in parallel with the reaction region R, and can be connected to a power supply V. A plurality of floating electrodes D that are not connected to the power supply V are arranged between the counter electrodes AB.
[0050]
The floating electrode group D of the second embodiment and the floating electrode group C of the first embodiment are common in that they are arranged so as to be scattered in the reaction region R. While the electrodes C are arranged in both the vertical and horizontal directions (see FIGS. 1 and 2), the floating electrodes D of the detection unit 1b differ in that they are arranged alternately (see FIG. 3). In FIG. 3, each floating electrode D has a circular shape. However, the shape is not particularly limited. The floating electrode D may have any shape such as a polygon, an ellipse, or the like that forms a non-uniform electric field.
[0051]
In the first and second embodiments described above, the groups of floating electrodes C or D are spaced apart in the reaction region R, that is, are scattered in a matrix, so that the lines of electric force concentrate in the reaction region R. There is an advantage that a large number of locations can be formed, and the non-uniformity of the electric field formed in the reaction region R can be enhanced.
[0052]
Further, since the floating electrodes C are arranged so as to be scattered in the reaction region R, hybridization can proceed over the entire reaction region R while ensuring free movement of the nucleotide chain. As a result, the range in which hybridization can be detected is widened over the entire reaction region R, and the detection sensitivity is improved.
[0053]
The arrangement interval of each floating electrode C group or each electrode of the D group is not particularly limited, but by setting the molecular length of the nucleotide chain X ′ for detection in an extended state to twice or more, the adjacent electrode C Free movement of the detection nucleotide chain X ′ can be secured between −C or D−D, and interference or steric hindrance between the fixed detection nucleotides X ′ can be prevented.
[0054]
On the other hand, by setting the arrangement interval of each floating electrode C to be shorter than the nucleotide chain X ′ for detection in the extended state, the nucleotide chain X ′ for detection is fixed so as to be cross-linked between the floating electrodes CC. Becomes possible.
[0055]
Hereinafter, an example of the “hybridization method” according to the present invention will be described with reference to FIG. FIG. 4 is a flowchart schematically showing the procedure of the method.
[0056]
First, FIG. 4 (A) shows a stage in which the detection nucleotide chain X is present in a rounded state immediately after being dropped onto the reaction region R. At this stage, the nucleotide chain for detection has not yet been immobilized on the floating electrode C (D).
[0057]
FIGS. 4B and 4C show the first procedure P of the hybridization method according to the present invention. ₁ Is shown. First, FIG. 4B shows a non-uniform electric field L in which a voltage is applied between the counter electrodes AB shown in FIGS. 1 to 3 and the lines of electric force concentrate on the surface of the floating electrode C (D). Are formed, the detection nucleotide chain X is extended along the lines of electric force, and is drawn to the floating electrode C (D). FIG. 4 (C) shows a stage in which one end of the extended detection nucleotide chain X ′ is fixed to the floating electrode C (D) after this stage.
[0058]
Subsequently, FIG. 4 (D) shows a stage where the target nucleotide chain Y has been added to the reaction region R. At this stage, voltage application to the counter electrodes AB is stopped, and the target nucleotide chain Y is in a rounded state. In addition, even at the stage of adding the target nucleotide chain Y to the reaction region R, the voltage application to the counter electrode AB may be continued.
[0059]
Next, FIGS. 4E and 4F show the second procedure P of the hybridization method according to the present invention. ₂ Is shown. First, FIG. 4 (E) shows that the voltage is again applied between the opposing electrodes AB to form a non-uniform electric field L in which the lines of electric force are concentrated on the surface of the floating electrode C (D). This is a stage in which the target nucleotide chain Y is extended along the line of electric force and is drawn to the nucleotide chain X ′ for detection.
[0060]
FIG. 4 (F) shows a stage in which the detection nucleotide chain X ′ and the target nucleotide chain Y ′ both in an extended state and hybridized are subjected to Brownian motion in a state where the voltage application is turned off.
[0061]
In the hybridization method according to the present invention, the voltage application between the opposing electrodes AB is performed in the operation example in which the switch S is kept on or the switch S is turned on / off intermittently in the stages shown in FIGS. Any of the operation examples to be performed dynamically can be adopted.
[0062]
The voltage is repeatedly turned on / off a desired number of times, and the voltage is intermittently applied to adjust the timing of fixing the electrode of the detection nucleotide chain X ′ or to detect the detection nucleotide chain X already fixed. With respect to ', the target nucleotide chain in the reaction region R can be made to approach stepwise, or the target nucleotide chain can be moved back and forth, and further, the timing of the reaction can be adjusted.
[0063]
Further, at the time of applying a voltage (particularly at the stage of FIG. 4 (F)), by securing a time during which the voltage is turned off, a linear target nucleotide chain and a linear detection nucleotide chain X ′ are formed. The reaction of forming a complementary strand, ie, hybridization, can be allowed to proceed exclusively to Brownian motion.
[0064]
By the above method, the complementarity between the detection nucleotide chain X ′ extended linearly and fixed to the electrode and the target nucleotide chain linearly extended similarly to the detection nucleotide chain X ′ The preferred result is that the formation of hydrogen bonds between certain bases, that is, hybridization, proceeds efficiently without the problem of steric hindrance, shortens the reaction time, and reduces the probability of showing false positives or false negatives. Can be
[0065]
The hybridization can be detected by a conventional method, for example, such as a fluorescent dye labeled on the target nucleotide chain Y or POPO-1 or TOTO-3, which specifically binds between bases of a double-stranded nucleotide. The fluorescence intercalator is irradiated with excitation light, and the resulting fluorescence can be detected using a conventional detector.
[0066]
More specifically, the reaction region R is excited by irradiating a laser beam (for example, a blue laser beam), the magnitude of the fluorescence intensity is detected by a detector (not shown), and the nucleotide chain X ′ for detection is detected. Of the hybridization between the nucleic acid and the target nucleotide chain. Finally, A / D conversion is performed on the fluorescence intensity for each reaction region R, and the binding reaction ratio can be visualized by distributing and displaying it on the screen of the computer C. In the present invention, the method for detecting hybridization is not particularly limited.
[0067]
【The invention's effect】
The present invention improves the hybridization efficiency and shortens the reaction time by immobilizing the nucleotide chain for detection, which has been adjusted to an extended state, over the entire reaction region that provides a hybridization site on the surface of the sensor chip such as DNA. In addition, it is possible to reliably improve the detection sensitivity and prevent the occurrence of false positive or false negative.
[Brief description of the drawings]
FIG. 1 is a diagram showing a main configuration of a first embodiment (1a) of a hybridization detection unit and a sensor chip according to the present invention.
FIG. 2 is a diagram showing a state where a non-uniform electric field (L) is formed in the detection unit.
FIG. 3 is a diagram showing a configuration of a main part of a second embodiment (1b) of a hybridization detection unit and a sensor chip according to the present invention.
FIG. 4 is a flowchart schematically showing the procedure of an embodiment of the hybridization method according to the present invention.
[Explanation of symbols]
1a, 1b Hybridization detector
A, B Counter electrode
C, D floating electrode (group)
R reaction area
S switch
V power supply
P ₁ First procedure
P ₂ 2nd procedure
X nucleotide chain for detection
X 'nucleotide chain for detection in extended state
Y Target nucleotide chain
Target nucleotide chain in Y 'extended state

Claims (8)

A reaction region serving as a place for hybridization between the nucleotide chain for detection and a target nucleotide chain having a base sequence complementary to the nucleotide chain for detection,
A counter electrode disposed in the reaction region,
A floating electrode disposed so as to be interspersed between the opposed electrodes. The hybridization detecting unit according to claim 1, wherein the floating electrode has a shape capable of forming a non-uniform electric field. The hybridization detection unit according to claim 1, wherein an electrode surface of the floating electrode is formed narrower than an electrode surface of the counter electrode. The hybridization detection unit according to claim 1, wherein the surface of the floating electrode is subjected to a surface treatment capable of fixing the nucleotide chain for detection. The hybridization detection unit according to claim 1, wherein the counter electrodes are arranged in parallel. A sensor chip comprising at least the hybridization detection unit according to claim 1. The sensor chip according to claim 6, wherein the electric field formed by the counter electrode is an alternating current. A reaction region serving as a place for hybridization between a nucleotide chain for detection and a target nucleotide chain having a nucleotide sequence complementary to the nucleotide chain for detection, a counter electrode disposed in the reaction region, and the counter electrode Using a plurality of floating electrodes disposed therebetween, and a detection unit including
By applying a voltage to the counter electrode, the detection nucleotide chain present in the reaction region is extended, and the detection nucleotide chain in the extended state is generated at a local surface site of the counter electrode and the floating electrode. Dielectrophoresis in a non-uniform electric field, a procedure of fixing to the surface portion of the floating electrode,
A procedure in which the target nucleotide chain present in the reaction region is extended by applying a voltage to the counter electrode, and hybridized with the detection nucleotide chain in the extended state fixed to the surface portion of the floating electrode. When,
A hybridization method comprising:

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