JP5026359B2 - Nucleic acid analysis device, nucleic acid analysis apparatus, and nucleic acid analysis method - Google Patents

Description

  The present invention relates to a nucleic acid analysis device, a nucleic acid analysis apparatus, and a nucleic acid analysis method.

  As techniques for analyzing nucleic acids, new techniques for determining the base sequences of DNA (DeoxyriboNucleic Acid) and RNA (RiboNucleic Acid) have been developed.

  Currently, in the base sequencing method using electrophoresis, a cDNA fragment synthesized from a DNA fragment for sequencing or an RNA sample by a reverse transcription reaction is prepared in advance, and a dideoxy reaction by a well-known Sanger method is performed. After execution, electrophoresis is performed and sequence analysis is performed by measuring a quantity analysis development pattern.

  On the other hand, in recent years, as disclosed in Non-Patent Document 1, for example, a method of fixing DNA or the like on a substrate and determining its base sequence has been proposed. In this method, a sample DNA fragment to be analyzed is captured on the substrate surface one molecule at a time, extended one molecule at a time, and the base sequence is determined by detecting the result by fluorescence measurement. Specifically, (1) four types of dNTP derivatives (MdNTPs) that are incorporated into a template DNA as a substrate for DNA polymerase and that can stop the subsequent DNA elongation reaction due to the presence of a protecting group and that have a label. A step of performing a DNA polymerase reaction, (2) a step of detecting the incorporated MdNTP with fluorescence, and (3) a step of returning the MdNTP to an extendable state as one cycle. By repeating this cycle, a sample is obtained. The DNA base sequence is determined. In this method, since DNA fragments can be sequenced one by one, a large number of fragments can be analyzed at the same time, and the analysis throughput can be increased. Furthermore, in this method, the base sequence can be determined for each single DNA molecule, which eliminates the need for cloning and PCR sample DNA purification and amplification steps that are problematic in conventional methods. Speed can be expected.

  In recent years, a so-called DNA chip or DNA microarray (hereinafter collectively referred to as a DNA chip) in which predetermined DNA is finely arrayed by microarray technology is used for gene mutation analysis, SNPs analysis, gene expression frequency. It has come to be used for analysis, etc., and has begun to be widely used in drug discovery, clinical diagnosis, pharmacogenomics, evolutionary research, forensic medicine, and other fields.

  This DNA chip is characterized in that comprehensive analysis of hybridization is possible because a wide variety of DNA oligo chains and nucleotide chains such as cDNA are integrated on a glass substrate or a silicon substrate. Hybridization is generally detected by detecting a fluorescent label of a nucleotide chain in a sample.

  In order to improve the detection accuracy of hybridization, various approaches have been proposed in order to reduce background noise caused by nonspecific adsorption of dust, fluorescent molecules, and the like to the substrate.

P.N.A.S. 2003, Vol.100, pp. 3960-3964 J. Chem. Phys. 2004, Vol. 120, pp. 357-366 BUNSEKI KAGAKU 2005, Vol.54, No.6, pp.459-465 Biophys J BioFAST 2007, Vol.106, pp.1529-1544 J.Phys.Chem.B. 2003, Vol.107, pp.668-677 P.N.A.S. 2006, vol.103, pp.19635-19640

  When analyzing a base sequence using an extension reaction on a substrate, as represented by the method disclosed in Non-Patent Document 1, one base extension reaction, washing of an unreacted substrate, and measurement are taken as one cycle. The so-called sequential reaction method is common. When analyzing the base sequence for each single DNA molecule, the fluorescence of one fluorescent dye molecule attached to the nucleotide incorporated on the probe by a single base extension reaction is measured. It is impossible to discriminate between fluorescent molecules associated with nucleotides captured on DNA and unreacted fluorescent molecules associated with unreacted nucleotides floating in the vicinity. It is essential to remove it. By entering this cleaning process, it is necessary to form complicated flow paths, liquid delivery devices, and waste liquid treatment devices on the substrate. In addition, a large amount of reaction reagents are consumed, and reactions necessary for total analysis are required. There was a problem that the time was long.

  In order to solve this problem, a means for discriminating between fluorescent molecules associated with nucleotides captured on the probe and fluorescent molecules associated with unreacted nucleotides is essential.

  In order to distinguish between fluorescent molecules associated with nucleotides captured on probe DNA and fluorescent molecules associated with unreacted nucleotides, only fluorescent molecules captured on probe DNA emit strong fluorescence, and are associated with unreacted nucleotides. It is necessary to create conditions so that the fluorescence derived from the fluorescent molecule is so weak that it can be ignored.

  It is conceivable that the nucleic acid analysis device containing the identification means is configured to fix a probe to a metal structure that generates a fluorescence enhancement field and capture fluorescent molecules on the probe.

  However, such a nucleic acid analysis device has two major problems. One of the problems is that it is difficult to fix the probe to the region where the fluorescence enhancement field of the metal structure is generated. Since the generation region of the fluorescence enhancement field due to localized surface plasmons is localized at several nm, it is very difficult to immobilize the nucleic acid probe specifically in this region with a technique such as blocking. There is a very high probability that the nucleic acid probe will be fixed to this site. If the nucleic acid probe is immobilized on a portion other than the fluorescence enhancement field, it becomes impossible to distinguish between the fluorescent molecule associated with the nucleotide captured on the nucleic acid probe and the fluorescent molecule associated with the unreacted nucleotide. Unnecessary “real-time” measurement system cannot be constructed.

  Another problem is that in the absence of a stirring mechanism or the like, it usually takes 24 hours or more to hybridize the nucleic acid sample to the nucleic acid probe, and a large amount of sample is required. A huge amount of money, time, and labor are required for hybridization. In particular, when analyzing a low expression gene, an extremely large number of target samples are required.

  The present invention has been made in view of such a situation, and specifically binds a nucleic acid probe to a fluorescence enhancement field generation region on a metal structure on a substrate, and also combines a target molecule and a probe molecule in a sample. Provided is a nucleic acid analysis device that increases specific binding speed and completes preparation for analysis in a short time and at low cost.

  In the nucleic acid analysis device of the present invention, a high-frequency alternating voltage is applied between two planar electrodes arranged so as to sandwich the substrate at the same time as light irradiation to the substrate having a metal structure. By irradiating the substrate with light, localized surface plasmons are generated in the metal structure on the substrate and an electric field distribution is created by applying a high-frequency AC voltage. A nucleic acid probe and a nucleic acid sample are specifically induced into the enhancement field. Utilizing this effect, the nucleic acid probe molecule is bound to a specific fine position (fluorescence enhancement field generating region) on the metal structure, and the hybridization rate between the nucleic acid probe and the sample nucleic acid is increased.

  According to the present invention, a nucleic acid probe is specifically bound to a fluorescence enhancement field generation region on a metal structure on a substrate, and the specific binding rate between a target molecule and a probe molecule in a sample is increased, and preparation for analysis is performed. Can be completed in a short time at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each embodiment shown in the drawings shows a representative example of a method and method related to the present invention, and the scope of the present invention should not be interpreted narrowly.

  FIG. 1 is a diagram for explaining the concept of the nucleic acid analysis device of the present invention. The nucleic acid analysis device is arranged so that the reaction region 3 is sandwiched between the first electrode 1 and the second electrode 2. On the reaction region 3 side of the first electrode 1, a substrate 5 having a metal structure 4 constructed in an array on the surface is disposed. As a material of the substrate 5, for example, sapphire, quartz and the like are suitable, and a size of about 10 mm square is suitable. The reaction region 3 functions as a space that provides a field for interaction between substances, and stores a nucleic acid probe solution, a sample solution, and the like. An AC electric field is applied to the reaction region 3 by the AC power source V via the first electrode 1 and the second electrode 2. Further, the surface of the first electrode 1 opposite to the surface on which the substrate 5 is disposed is irradiated with excitation light. The first electrode 1 may be any material that cannot completely reflect the irradiated light, but is preferably formed of a transparent conductor. For example, ITO (indium-tin-oxide) is suitable. The first electrode 1 may be provided with an installation site for the substrate 5.

  In order to bind the nucleic acid probe to the fluorescence enhancement field generating region of the metal structure 4, a solution of the nucleic acid probe P is stored in the reaction region 3, and an alternating electric field is applied via the first electrode 1 and the second electrode 2. At the same time, the first electrode 1 is irradiated with excitation light.

  Localized surface plasmons are induced on the metal structure 4 by the excitation light that has passed through the first electrode 1.

  By applying an alternating electric field, the nucleic acid probe P can be induced and bound to a specific fine position (fluorescence enhancement field generation region) where the localized surface plasmon of the metal structure 4 is induced by using dielectrophoresis. it can.

Dielectrophoresis is a method of generating an induced dipole in a molecule by applying an alternating voltage to a sample solution, and driving the molecule toward a strong electric field in a field where the electric field is not uniform. In particular, in a high-frequency AC electric field, the force acts on the dipole in proportion to the gradient of the square of the average electric field (２E ² ). Therefore, in a portion where a large electric field gradient is generated as in the localized surface plasmon generation region. Has an extremely large dielectrophoretic force. This approach can be applied to any molecule that polarizes and produces an induced dipole, regardless of whether the molecule is charged. In addition, unlike electrophoresis, there is no need to control the sign of the potential of the target site of the molecule, and when a nucleic acid probe having a negative charge is directed to a specific fine position, a specific fine position (region of several nm) There is no difficulty that it is necessary to control so that only the potential of becomes positive.

  In addition, a sample nucleic acid solution is stored in the reaction region 3 in a state where the nucleic acid probe is bound to the metal structure 4, and an alternating electric field is applied through the first electrode 1 and the second electrode 2 in the same manner as described above. In addition, by irradiating the first electrode 1 with excitation light, the sample nucleic acid can be induced in the vicinity of the nucleic acid probe, and the hybridization rate between the nucleic acid probe and the sample nucleic acid can be improved.

  The light irradiation conditions for the substrate are desirably the same as the light irradiation conditions used for the analysis.

  The nucleic acid analysis device of the present invention utilizes the feature that the fluorescence enhancement field and the electric field enhancement field coincide with each other, and can specifically fix the nucleic acid probe to a minute region that produces the fluorescence enhancement effect, thereby removing the unreacted substrate with the fluorescent molecule. The base extension reaction can be measured without

As a metal structure on the substrate on which strong localized surface plasmon is generated by light irradiation, for example, SiO ₂ or the like between _two disk-like metals 23 and 24 as shown in FIG. 3 or a cone-shaped metal structure 34 with a sharpened tip, as shown in FIG. 3, covered with an insulating layer 33 such as SiO ₂ so that only the tip is exposed. Etc. are suitable. As long as the shape has a vertex, a polyhedron such as a triangular pyramid or a quadrangular pyramid may be used instead of the cone shape. Further, as will be described later, the insulating layer 33 can be omitted. These metal structures have a size of about several nanometers, and are arranged in an array of millions on the substrate. As a metal used for these metal structures, a noble metal such as gold, silver, or platinum is preferable. As the insulating layer, an inorganic material such as SiO ₂ or an organic material typified by polyimide may be used.

  In a metal structure in which an insulating layer is inserted between the metals as shown in FIG. 2, in order to bind the nucleic acid probe to the metal structure, a suitable function is used by utilizing the difference in chemical properties between the metal surface and the insulating layer. There is a method of attaching a group to an insulating layer or modifying a functional group at the end of a nucleic acid probe and reacting it with a metal structure. In such a conventional method, a fluorescence enhancement field is generated. It is very difficult to bind a nucleic acid probe to a desired specific fine position. This is because, as can be seen from the electric field strength simulation results described in Non-Patent Document 2, an enhanced electric field is not generated equivalently around the insulating layer in the structure, but an enhanced electric field is generated only in a part of the insulating layer. This is because it does not occur. Even if the difference in chemical properties between the metal surface and the insulating layer is used, the nucleic acid probe is bound to the insulating layer equivalently, so that a fluorescence enhancement field other than the desired specific fine position does not occur. The probability of the fluorescent probe binding to the region is overwhelmingly high.

The nucleic acid analysis device of the present invention solves such a problem as follows. A method using aminosilane treatment will be described as an example. First, amino groups are introduced into the SiO ₂ film, which is an insulating layer of the metal structure, by aminosilane treatment. Thereafter, biotin-succinimide (NHS-Biotin manufactured by Pierce) is reacted, and then streptavidin is reacted. At this stage, streptavidin is bonded to the entire SiO ₂ film. Next, the metal structure is then placed on the apparatus of the present invention, and a nucleic acid probe solution previously modified with biotin at its end is stored in the reaction region 3 and then a high frequency AC voltage of 50 kHz to 1 MHz is applied. And light irradiation to the substrate at the same time. As a result, the biotin-modified nucleic acid probe migrates in a direction where a large electric field gradient exists, that is, toward a specific fine position where an enhanced electric field exists. In this way, the nucleic acid probe can be bound to a desired specific fine position.

In the metal structure in which the metal with the tip sharpened as shown in FIG. 3 is covered with SiO ₂ and only the tip portion is exposed, the nucleic acid probe is made into a metal structure using the difference in chemical properties between the metal and SiO _2. There are ways to bind to the body. Specifically, a metal structure with a probe nucleic acid is introduced by reacting a probe nucleic acid modified with a functional group such as a thiol group at the end while introducing a hydroxy group on the SiO ₂ film by hydroxysilane treatment to prevent non-specific adsorption. It is a method of producing a body. However, in this conventional method, it is difficult to bind a probe nucleic acid to a desired specific fine position where a fluorescence enhancement field is generated. According to the electric field strength simulation result for the Ag triangular prism of Non-Patent Document 2, the enhanced electric field is localized in a region of several nm centering on the apex of the structure. Therefore, combining spin coating and etching so that only this region is exposed. It is very difficult to produce a SiO ₂ film.

  Even if the exposure of the tip portion is suppressed to 10 nm, the probe nucleic acid is bound to a site other than the enhanced electric field generation region with a high probability. If the thin film covering the metal structure adversely affects the characteristics as a nucleic acid analysis device, the thin film must be removed after binding the probe nucleic acid. There is a possibility that adverse effects such as detachment of nucleic acids and detachment of metal structures from the substrate may occur.

  The nucleic acid analysis device of the present invention solves this problem as follows. In the nucleic acid analysis device of the present invention, it is possible to remove the process of covering the metal structure with a thin film and exposing only the tip portion. A substrate on which a metal structure with a sharpened tip is constructed is placed in the apparatus of the present invention, and a nucleic acid probe solution that has been previously modified with a thiol group at the end is stored in the reaction region 3, and then a high frequency of 50 kHz to 1 MHz Application of AC voltage and light irradiation to the substrate are performed simultaneously. As a result, the thiol group-modified nucleic acid probe migrates in a direction in which a large electric field gradient exists, that is, in a specific fine position (an apex site of the metal structure) where an enhanced electric field exists. In this way, the nucleic acid probe can be bound to a desired specific fine position.

  Here, the dielectrophoretic force generated when the probe nucleic acid is immobilized by the nucleic acid analysis device of the present invention will be specifically described below.

First, the dielectrophoretic force is expressed by the following equation.
F = 2πε _m r ³ Re [K (ω)] ∇E ²
In the above equation, ε _m is the dielectric constant of the solvent, r is the particle radius including the dynamic ion cloud, K (ω) is the Clausius-Mossotti factor, and E is the electric field.

For nucleic acids, when water is used as a solvent, Re [K (ω)] has a positive value at a frequency of 1 kHz to 1 MHz, so that the dielectrophoretic force acts in a direction in which ∇E ² becomes a large value. There have been a number of studies on DNA migration using dielectrophoresis, and various types of electrodes have been used. There are various other types such as a quadrupole electrode used in Non-Patent Document 3, an electrode capable of increasing the conductivity only in the light irradiation part used in Non-Patent Document 4, a spiral electrode, etc. Shaped electrodes are used. In Non-Patent Document 3, Non-Patent Document 4, and Patent Document 2, the minimum value of ∇E ² required to move DNA is 10 ⁹ to 10 ¹⁰ [V ² / m ³ ], which corresponds to the end point of electrophoresis. ∇E ² , that is, the highest value of ∇E ² is 10 ¹¹ to 10 ¹³ [V ² / m ³ ].

After the substrate is set on the nucleic acid analysis device of the present invention and the nucleic acid probe solution is stored in the reaction region, the metal structure is formed as a convex portion on the substrate when only high frequency AC voltage is applied without light irradiation. Therefore, the electric field concentrates in this direction, and an electric field gradient is generated. At this time, if the applied voltage is 10 V and the distance between the electrodes is 1 mm, a gradient of ∇E ² = 10 ¹⁰ [V ² / m ³ ] occurs. As a result, the dielectrophoretic force acts in the direction in which the metal structure exists. In this state, the nucleic acid probe is attracted to the entire metal structure, and the nucleic acid probe is bound to a specific fine position on the metal structure. I can't.

  On the other hand, the substrate is set on the nucleic acid analysis device of the present invention, and after storing the nucleic acid probe solution in the reaction region, the substrate is irradiated with light simultaneously with the application of the high-frequency alternating voltage, and the substrate is exposed on the metal structure When localized surface plasmons are generated, as can be seen from the simulation results of Non-Patent Document 2 and Non-Patent Document 5, a very large electric field gradient is generated at specific fine positions on the metal structure. Due to this effect, the nucleic acid probe is attracted to the vicinity of the metal structure, and further guided toward a specific fine position on the metal structure.

Next, E and ∇ E ² generated in the vicinity of specific fine positions on the metal structure will be described. In a metal structure in which an insulating layer is inserted between metals as shown in FIG. 2, Au is used for the metal portion, and a metal structure having the design value shown in the figure is used to generate localized surface plasmons. Therefore, when light having a wavelength of 533 nm is totally reflected on the substrate, the enhancement field is formed only in a part around the SiO ₂ depending on the light irradiation direction. For this part, against the horizontal direction (OA direction), distance and E from the point O, and relationship between the values of ∇E ² shown in the graph of FIG. 4, with respect to the direction of 30 degrees from the horizontal direction (OB direction), the point distance from O and E, the relationship between the values of ∇E ² shown in the graph of FIG. According to these graphs, the horizontal direction, in the A point spaced 20nm of SiO ₂ surface has a gradient of ^{∇E 2 = 10 10 [V 2} / m 3], gets closer to the SiO ₂ surface, ∇E The value of ² increases rapidly and becomes ∇E ² = 1.2 × 10 ¹³ [V ² / m ³ ] at a point of 10 nm from the SiO ₂ surface. Further, with respect to the direction of 30 degrees from the horizontal direction, at a point B 23 nm away from the SiO ₂ surface, it has a gradient of ∇E ² = 1.2 × 10 ¹⁰ [V ² / m ³ ], and SiO ₂ As approaching the surface, the value of ∇E ² increases rapidly and becomes ∇E ² = 1.4 × 10 ¹³ [V ² / m ³ ] at a point of 10 nm from the SiO ₂ surface. From these calculated values, it is predicted that after the nucleic acid is induced to the vicinity of the metal structure, it is induced to an enhanced field forming site existing between Au with a strong force.

A metal structure having a sharpened tip as shown in FIG. 3 is covered with SiO ₂ and only the tip is exposed, Au is used for the metal, and the metal structure having the design value shown in the figure is obtained. When used, when a 533 nm wavelength light is totally reflected on the substrate to generate localized surface plasmons, an enhancement field is formed at the tip of the cone. For this portion, it indicated distance from the vertex and E, the relationship between the values of ∇E ² in the graph of FIG. According to this graph, at a point 20 nm away from the apex, it has a gradient of ∇E ² = 1.1 × 10 ¹⁰ [V ² / m ³ ], and the value of ∇E ² becomes closer to the SiO ₂ surface. It increases rapidly and becomes 頂点 E ² = 6.3 × 10 ¹³ [V ² / m ³ ] at the apex portion. From these calculated values, it is predicted that after the nucleic acid is induced to the vicinity of the structure, it is induced to the apex portion of the cone, which is the site for forming the enhancement field, with a strong force.

  In addition, it is possible to increase the hybridization rate between the probe nucleic acid and the sample nucleic acid immobilized at specific fine positions of the metal structure on the same principle.

  Further, the distance between the electrodes may be adjusted using a micrometer stage.

  As described above, by using the nucleic acid analysis device of the present invention in which the dielectrophoresis technique and the localized surface plasmon generation technique are combined, the probe molecule can be moved to a specific fine position on the nm scale, which has been difficult until now. The selective binding and the specific binding rate of the target molecule to the probe can be increased, the manufacturing process of the substrate for single molecule measurement can be shortened, the stable high fluorescence enhancement effect can be realized, and the measurement pretreatment time such as hybridization TAT (Turn Around Time) can be shortened by shortening.

  Examples of the nucleic acid analyzer will be described. An example of a preferred configuration of a nucleic acid analyzer using a nucleic acid analysis device will be described with reference to FIG.

  In this embodiment, a means for supplying a nucleotide having a fluorescent dye, a nucleic acid synthase, and a nucleic acid sample to a nucleic acid analysis device having a nucleic acid probe immobilized thereon as shown in FIGS. And a luminescence detection means for measuring the fluorescence of the fluorescent dye incorporated into the nucleic acid chain by the nucleic acid extension reaction caused by the coexistence of nucleotides, nucleic acid synthase, and nucleic acid sample on the nucleic acid analysis device. Prepare. More specifically, the nucleic acid analysis device 505 of the present invention is installed in a reaction chamber composed of a cover plate 501, a detection window 502, an inlet 503 that is a solution exchange port, and an outlet 504. Note that PDMS (Polydimethylsiloxane) is used as the material of the cover plate 501 and the detection window 502. The thickness of the detection window 502 is 0.17 mm. Laser light 510 and 509 oscillated from a YAG laser light source (wavelength 532 nm, output 20 mW) 507 and a YAG laser light source (wavelength 355 nm, output 20 mW) 508 are circularly polarized by a λ / 4 plate 511, and only the laser light 509 is circularly polarized. The two laser beams are adjusted to be coaxial by 512 (reflecting 410 nm or less), then condensed by a lens 513, and then irradiated to the device 505 through a prism 514 at a critical angle or more. According to this example, localized surface plasmons are generated in the metal structure of the nucleic acid analysis device 505 by laser irradiation, and the target substance phosphor captured by the nucleic acid probe bound to the metal structure is within the fluorescence enhancement field. Will exist. The phosphor is excited by laser light, and a part of the enhanced fluorescence is emitted through the detection window 502. Further, the fluorescence emitted from the detection window 502 is converted into a parallel light beam by the objective lens 515 (× 60, NA 1.35, differential distance 0.15 mm), and the background light and the excitation light are blocked by the optical filter 516. The image is formed on the two-dimensional CCD camera 518 by the image lens 517.

  In the case of the sequential reaction method, as disclosed in Non-Patent Document 6 as a nucleotide with a fluorescent dye, a 3′-O-allyl group is introduced as a protecting group at the 3′OH position of ribose. Those linked to a fluorescent dye via an allyl group at the 5-position or at the 7-position of purine can be used. Since the allyl group is cleaved by light irradiation or contact with palladium, quenching of the dye and control of the extension reaction can be achieved simultaneously. Even in the sequential reaction, it is not necessary to remove unreacted nucleotides by washing. Furthermore, since no washing step is required, the extension reaction can be measured in real time. In this case, it is not necessary to add a 3′-O-allyl group as a protecting group at the 3′OH position of ribose in the nucleotide, and the nucleotide is linked to the dye via a functional group that can be cleaved by light irradiation. May be used.

  As described above, by assembling a nucleic acid analyzer using the nucleic acid analysis device of the present embodiment, the analysis time can be shortened and the device and the analysis apparatus can be simplified without using a washing step, and the sequential reaction method. In addition, it becomes possible to measure the elongation reaction of bases in real time, and the throughput can be greatly improved as compared with the prior art.

It is a figure for demonstrating the concept of the nucleic acid analysis device of this invention. It is a figure for demonstrating an example of operation | movement of the nucleic acid analysis device of this invention using the metal structure which inserted the insulating layer between the metals. It is a figure for demonstrating an example of operation | movement of the nucleic acid analysis device of this invention using a cone-type metal structure. In the metal structure obtained by inserting an insulating layer between the metal, with respect to the horizontal direction is a graph showing the relationship between the distance and E, ∇E ² values from the point O. In the metal structure obtained by inserting an insulating layer between the metal, to the direction of 30 degrees from the horizontal direction is a graph showing the relationship between the distance and E, ∇E ² values from the point O. In cone-type metal structure is a graph showing the relationship between the distance and E, ∇E ² values from the vertex. It is a figure which shows an example of a structure of the nucleic acid analyzer using a nucleic acid analysis device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st electrode 2 2nd electrode 3 Reaction area | region 4, 34 Metal structure 5 Board | substrate 22, 33 Insulating layer 23, 24 Metal 501 Cover plate 502 Detection window 503 Inlet 504 Outlet 505 Nucleic acid analysis device 507,508 YAG Laser light sources 509 and 510 Laser light 511 λ / 4 plate 512 Dichroic mirror 513 Lens 514 Prism 516 Optical filter 517 Imaging lens 518 Two-dimensional CCD camera

Claims (5)

A nucleic acid analysis method for analyzing nucleic acid in a sample by fluorescence measurement,
A step of disposing a smooth support substrate in which a metal structure in which localized surface plasmons are generated by light irradiation is arranged in an array on one of two electrodes arranged so as to sandwich a reaction region;
Supplying a probe solution to the reaction region;
A step of applying an alternating voltage to the two electrodes and irradiating the metal structure with light to couple a probe to the metal structure , causing dielectrophoresis to cause the probe to fluoresce in the metal structure Inductively coupled to the generation region of the enhancement field; and
Supplying a nucleotide having a fluorescent dye, a nucleic acid synthase, and a nucleic acid sample to the reaction region;
Applying an alternating voltage to the two electrodes and irradiating the metal structure with light;
And a step of measuring fluorescence of a fluorescent dye incorporated in a nucleic acid chain by a nucleic acid extension reaction caused by the coexistence of the nucleotide, the nucleic acid synthase, and the nucleic acid sample. 2. The nucleic acid according to claim 1 , wherein the metal structure is one in which a metal body, an insulating layer, and a metal body are sequentially stacked in a direction perpendicular to the surface of the support substrate. Analysis method. The nucleic acid analysis method according to claim 1 , wherein the metal structure is made of a metal having a shape having a vertex. The nucleic acid analysis method according to claim 3 , further comprising an insulating layer, wherein a part of the metal structure is exposed from the insulating layer. The nucleic acid analysis method according to claim 3 , wherein the metal structure has a conical shape or a polygonal pyramid shape.

Images