JP3991008B2 - Electrophoresis apparatus, capillary array, and electrophoresis method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a capillary electrophoresis apparatus for separating and analyzing a sample such as DNA or protein.
[0002]
[Prior art]
The prior art of the capillary electrophoresis apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-360262. Here, a capillary array composed of 16 capillaries is used. Each of the 16 capillaries is inserted into a hollow electrode made of a thin pipe made of stainless steel (hereinafter referred to as SUS). The sample introduction end of the capillary protrudes slightly from the hollow electrode and is fixed with an epoxy adhesive. The capillary is a quartz pipe whose outer jacket is coated with polyimide resin. The hollow electrode is made of SUS304 or SUS with high corrosion resistance.
Austenitic stainless steel such as 316.
[0003]
[Patent Document 1]
JP 2002-360262 A
[0004]
[Problems to be solved by the invention]
If the hollow electrode is a hard metal, when the capillary is inserted into the hollow electrode (during creation) or when the user touches the capillary (during use), the capillary's polyimide coating will be damaged and the capillary will be broken. There is. When a high voltage is applied to the broken capillary, it is discharged from the broken part, and thus electrophoretic analysis cannot be performed.
[0005]
In addition, the following problems also occur in an electrophoresis apparatus that irradiates laser light so as to propagate through a plurality of capillaries. In this method, the refractive index around the capillary, the electrophoresis medium, and the capillary is adjusted to reduce the divergence of the laser light propagating through the capillary. For this reason, if there is a capillary that cannot be filled with a separation medium due to breakage, a problem occurs in the propagation of laser light, and electrophoretic analysis cannot be performed.
[0006]
Therefore, if even one capillary breaks, the capillary array itself is discarded.
[0007]
An object of the present invention relates to avoiding capillary breakage.
[0008]
[Means for Solving the Problems]
The present invention relates to making a material of an electrode holding a capillary plastic. Since the electrodes are softer than the capillaries, breakage during capillary array creation and use can be avoided.
[0009]
The plastic electrode in the present invention includes an electrode whose material is plastic. The shape of the plastic electrode includes a pipe shape that can penetrate the capillary inside, and a U shape that can fit the capillary into the recess.
[0010]
The above and other novel features and effects of the present invention will be described below with reference to the drawings.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
[Example 1]
FIG. 1 is a schematic diagram of an electrophoresis apparatus, and FIG. 2 is a schematic diagram of a capillary array. Hereinafter, an outline of the electrophoresis apparatus will be described.
[0012]
The capillary 1 generally has an outer diameter of 0.1 to 0.3 mm and an inner diameter of 0.02 to 0.1 mm, and the outer cover is coated with a resin such as polyimide. The capillary 1 holds therein a gel that is a separation medium for electrophoretic separation of the sample. The capillaries themselves are quartz pipes, and a plurality of capillaries (several tens to 100 are common) are arranged to constitute a capillary array. In this embodiment, 96 capillaries are used in which a quartz pipe having an inner diameter of 0.050 mm and an outer diameter of 0.126 mm is coated with 0.012 mm of polyimide.
[0013]
The capillary array includes a load header 4, a detection unit 5, a capillary head 17, and a separator 16. The load header 4 holds one end of the capillary and the plastic hollow electrode 20 in a matrix corresponding to the arrangement of the sample container 2. Then, DNA is taken into the capillary by electrophoresis. The detection unit 5 arranges and fixes 96 capillaries 1 in parallel in the order of the sample number of the load header, and emits fluorescence 10 which is signal light depending on the sample separated by electrophoresis when irradiated with excitation light. The capillary head 17 on the opposite side of the load header 4 bundles 96 capillaries 1 and attaches them to the buffer solution container 14 containing the buffer solution 13 in a pressure-tight and air-tight manner. A large number of capillaries are aligned by the separator 16. The capillary array is a consumable item that is discarded when the separation performance deteriorates after electrophoresis for several months or several hundred times.
[0014]
In addition, the electrophoresis apparatus includes a sample tray 3 that holds a plurality of samples, an excitation optical system that irradiates each capillary with excitation light, a detection optical system that detects signal light from each capillary, and a high-voltage power supply 15 that electrophores the sample. including.
[0015]
The sample tray 3 incorporates a plurality of sample containers 2 containing fluorescently labeled DNA samples. In this embodiment, 96 samples can be held simultaneously.
[0016]
The excitation optical system irradiates laser light emitted from the laser light source 6 from both sides of the detection unit 5 via the mirror 7, the beam splitter 8, and the condenser lens 9. Laser light, which is excitation light narrowed down to a thickness approximately equal to the inner diameter of the capillary, is irradiated from both sides of the capillaries arranged in a flat plate shape. In this embodiment, laser is irradiated from both side surfaces of a capillary array containing DNA or protein to be electrophoresed. The laser can be focused by the lens action of the capillaries, and all the capillaries can be irradiated with excitation light. By irradiating excitation light from both sides, each capillary can be excited to an equal intensity.
[0017]
The detection optical system is a sensor including a detection lens system 11 that detects fluorescence 10 that is signal light and a CCD camera 12. The detected fluorescence 10 is processed by the signal processing device 21. In the present embodiment, 96 capillaries 1 are arranged in parallel on an optical flat plane with an accuracy of several microns in height, and excitation light is skewed and irradiated from both sides to obtain signal light.
[0018]
The high voltage power supply 15 applies a high voltage of about 15 kV to the buffer container 14 and the load header 4. At the time of sample introduction, a high voltage is applied to the current path including the buffer solution 13, the separation medium in the capillary 1, the sample in the sample container 2, and the plastic hollow electrode 20. Thereby, the sample in the sample container 2 is taken in from the sample introduction end 33. At the time of electrophoretic separation, a buffer solution container is disposed instead of the sample tray 3, and a high voltage is applied to the current path including the buffer solution 13, the separation medium in the capillary 1, the buffer solution, and the plastic hollow electrode 20. Thereby, the sample introduced into the sample introduction end 33 is separated by electrophoresis. While the DNA sample passes through the electrophoresis medium filled in the entire area of the capillary, the passage resistance varies depending on the size of the sample (also expressed as long or short), and therefore the sample reaches the detection section earlier in ascending order. The detector 5 irradiates the capillary 1 with a laser,
Excites fluorescent markings on DNA samples. A CCD camera 12 detects fluorescence 10 that is signal light corresponding to four types of nucleoside bases, adenine, guanine, cytosine, and thymine. Then, the signal processing device 21 analyzes the DNA sample from the detected fluorescence 10 and specifies the base sequence.
[0019]
3A is a schematic front sectional view of the load header, and FIG. 3B is a schematic side sectional view of the load header. FIG. 4 is a detailed partial sectional view of the load header. Hereinafter, the structure of the load header will be described.
[0020]
The load header 4 holds 96 capillaries 1 and plastic hollow electrodes 20 corresponding to the capillaries in a matrix of 8 rows and 12 columns. Recessed grooves (not shown) are respectively formed on the two opposing side surfaces of the load header 4. By fitting this onto two convex rails provided in the electrophoresis apparatus, the capillary array can be mounted on the electrophoresis apparatus. By attaching the load header 4 to the electrophoresis apparatus, the tips of the capillary 1 and the plastic hollow electrode 20 can be arranged at positions corresponding to the sample container 2. In addition, by attaching the load header 4 to the electrophoresis apparatus, the conductive rubber 23 that contacts the plastic hollow electrode 20 is connected to a high voltage contact (not shown) on the electrophoresis apparatus side. Thereby, the plastic hollow electrode 20 and the high voltage power supply 15 are electrically connected.
[0021]
More specifically, each of the 96 capillaries 1 is inserted into a plastic hollow electrode 20 which is a thin plastic pipe. A sample introduction end 33, which is a capillary tip into which a sample can be introduced, is fixed with an epoxy adhesive 27 so as to be flush with the tip of the plastic hollow electrode 20. The plastic hollow electrode 20 inside the load header passes through 96 holes provided in the conductive rubber 23 and is fixed. Thereby, the plastic hollow electrode 20 and the conductive rubber are electrically connected. The 96 plastic hollow electrodes 20 are aligned and fixed to the holder 25 by an adhesive 27. The conductive rubber 23 to which a high voltage is applied during electrophoresis is incorporated in the holder 25 and the lid 26. A part of the conductive rubber 23 is bent by 90 °, is substantially parallel to the plastic hollow electrode 20, and is disposed in the vicinity of the opening provided in the holder 25. A high voltage contact is inserted from this opening, and the high voltage contact is brought into contact with the conductive rubber 23. The holder 25 and the lid 26 are fixed by ultrasonic bonding. The capillary 1 is fixed to the lid 26 with a filling adhesive 28 and sealed with a UV adhesive 34. This prevents the capillary from being pulled out and high voltage leakage.
[0022]
Hereinafter, the plastic hollow electrode 20 will be described in detail.
[0023]
The plastic hollow electrode 20 is preferably a plastic pipe mixed with conductive powder, or a plastic pipe coated with a conductive polymer.
[0024]
The material of the plastic pipe is preferably a thermoplastic material. This is because plastic can be easily formed by applying heat. Further, it is desirable that the plastic pipe does not contain chlorine, sulfur, or a metal that is easily ionized. This is because the corrosion resistance of the hollow electrode is increased and deterioration due to contact with a sample or the like can be prevented. Further, it is possible to prevent ions from being mixed into the sample from the plastic hollow electrode 20, and to avoid deterioration in sensitivity of electrophoretic analysis. As specific materials for the plastic pipe, for example, polyether ether ketone, polyethylene terephthalate, polybutylene terephthalate, polyimide, polyether imide, polyethylene, polycarbonate, polyester, and the like are preferable.
[0025]
When carbon powder or metal powder is mixed with a plastic material to impart conductivity, if the mixing amount of carbon powder or the like is less than 30%, a sufficient resistance value as a hollow electrode cannot be obtained. On the other hand, if it exceeds 30%, the fluidity of the plastic material decreases and becomes brittle, so that it is difficult to form a hollow electrode. For this reason, carbon nanotubules, which are one type of ultrafine carbon, are mixed with a plastic material by several percent to several tens percent, and this is stretched to produce a plastic hollow electrode 20.
[0026]
The plastic material containing carbon nanotubes has improved conductivity when stretched. This is presumably because the carbon nanotubes are entangled with each other when stretched due to the orientation of the carbon nanotubes. For this reason, a sufficient resistance value can be obtained only by mixing a small amount of carbon nanotubes, and the fluidity of the plastic material is not impaired. Moreover, the tensile strength of the plastic material is increased by mixing the carbon nanotubes. This is considered that the tensile strength of the carbon nanotube was provided. Therefore, even if the plastic material has a small outer diameter and a thin pipe shape (for example, an outer diameter of 1 mm and an inner diameter of 0.5 mm), sufficient strength can be ensured. Therefore, if a plastic material containing carbon nanotubes is used, a plastic hollow electrode 20 having a sufficient resistance value can be produced.
[0027]
In addition, as the plastic hollow electrode 20, a plastic pipe coated with a conductive polymer can be used. As the conductive polymer, a polypyrrole-based or polysilane-based polymer is used. Since existing plastic pipes can be used, plastic hollow electrodes can be made at a relatively low cost.
[0028]
When applied only to the inner surface, the conductive polymer hardly touches the sample and the like, so that the plastic hollow electrode can be prevented from being altered or deteriorated. For this reason, adverse effects on electrophoresis can be avoided. Further, when applied only to the outer surface, the distance from the center of the capillary to the conductive polymer increases. When the hollow electrode is brought into contact with the sample and a voltage is applied, an electric field is generated in a wide range, so that more samples can be introduced.
[0029]
A plastic hollow electrode 20 may be formed by combining a plurality of types of plastic pipes. In this case, an effective plastic hollow electrode 20 can be obtained by well combining the characteristics of the plastics. For example, a plastic hollow electrode having a double pipe structure in which the outside is made of highly corrosion-resistant plastic and the inside is made of high-strength plastic can be considered. In this case, the plastic hollow electrode 20 can have both corrosion resistance and strength.
[0030]
Alternatively, a plastic hollow electrode 20 may be formed by forming a mixed material obtained by mixing a plurality of types of plastic materials. Also in this case, an effective plastic hollow electrode 20 can be obtained by well combining the characteristics of the plastics. For example, use of an expensive PEEK excellent in heat resistance, strength, and corrosion resistance and an inexpensive polyethylene mixed material can be considered. In this case, a plastic hollow electrode
No. 20 has sufficient heat resistance, strength, and corrosion resistance, and can be made relatively inexpensively.
[0031]
Since the plastic hollow electrode 20 as described above is softer than the capillary, the capillary is not damaged. For this reason, it is possible to eliminate the capillary breakage during the creation and use of the capillary array.
[0032]
Here, the resistance value (Rd) of the hollow electrode will be described. Rd is determined by the following equation.
[0033]
Rd / (Rc + r) ≦ A
Rc: Capillary resistance (value for one capillary)
r: resistance of the system other than the capillary section
A: Stability of high voltage power supply
That is, if the resistance ratio of the hollow electrode to the total resistance of the electrophoresis system is smaller than the stability A of the high-voltage power supply, there is no problem in electrophoresis even if the resistance of the hollow electrode becomes unstable.
[0034]
In an actual electrophoresis system, the resistance Rd of the hollow electrode constituting r, the internal resistance of the high-voltage power supply, the electric circuit resistance other than the capillary, the plus electrode resistance of the gel solution container, etc. are very small compared to Rc. That is, r << Rc, and Rd is obtained by the following equation.
[0035]
Rd ≦ Rc × A
Rc is generally 100 to 10,000 MΩ, although it depends on the length and inner diameter of the capillary and the type of gel. Further, since the stability of the high voltage power supply is 1/10000, Rd is expressed by the following equation.
[0036]
Rd ≦ 0.01-1MΩ
That is, it is desirable that the resistance value of the hollow electrode be 0.01 to 1 MΩ.
[0037]
Hereinafter, manufacture of the load header 4 provided with the plastic hollow electrode 20 is demonstrated. FIG. 5 is a detailed partial sectional view showing a flare forming process of the plastic hollow electrode. FIG. 6 is a detailed partial cross-sectional view of the load header during production. Hereinafter, each manufacturing process of the load header and its outline will be described.
[0038]
(1) Adhesion between holder and plastic hollow electrode
96 plastic hollow electrodes 20 are respectively inserted into openings of 8 rows and 12 columns provided in the holder 25 and fixed by an adhesive 27. At this time, the length of the plastic hollow electrode 20 protruding from the holder 25 is made constant so that the tip thereof is on the same plane.
[0039]
(2) Formation of plastic hollow electrode
A heated cone-shaped flare core 29 is used to form one end of the plastic hollow electrode 20 in a flare shape. FIG. 5A shows a state immediately before formation, and FIG. 5B shows a state immediately after formation.
[0040]
The saji jig 30 is placed on the holder 25 and the saji jig 30 is applied to the plastic hollow electrode 20 protruding into the holder 25. A cone-shaped flare core 29 is disposed above the plastic hollow electrode. At this time, the center axis of the flare core 29 and the plastic hollow electrode are matched. Then, while the flare core 29 is heated and rotated, it is inserted into the plastic hollow electrode 20. The plastic hollow electrode 20 in contact with the flare core 29 is deformed by heat, and the inside thereof is the flare core.
29 shapes. The outside of the plastic hollow electrode 20
It is received at 30 and becomes its shape. By removing the flare core 29 and the sagging jig 30 and cooling them with air, the plastic hollow electrode 20 is solidified into a flare shape. As described above, by using a plastic material for the hollow electrode, the end portion of the hollow electrode can be easily formed into a flared shape. Since plastic is also deformed by ultrasonic waves, the above-described formation can be performed by applying ultrasonic waves to the flare core 29.
[0041]
(3) Attaching conductive rubber to plastic hollow electrode
Conductive rubber 23 is attached to 96 plastic hollow electrodes 20 projecting inside holder 25. The ends of the flared hollow electrodes are respectively directed to openings provided in the conductive rubber 23 in 8 rows and 12 columns, and the conductive rubber 23 is pushed in. Thereby, the plastic hollow electrode 20 is inserted into the opening of the conductive rubber 23 and is electrically connected.
[0042]
(4) Ultrasonic bonding of holder and lid
The plastic holder 25 is put on the plastic holder 25 and bonded by ultrasonic waves.
[0043]
(5) Capillary insertion into a plastic hollow electrode
The capillaries 1 are inserted into the flared openings arranged in the lid 26 so as to form 8 rows and 12 columns. The capillary 1 is inserted into the hollow electrode from the end of the flared hollow electrode that exists directly under the opening. Since the material of the hollow electrode is softer than the capillary 1, the capillary is not broken even if a somewhat large load is applied.
[0044]
(6) Application of filling adhesive
The filling adhesive 28 is applied to the flared opening disposed in the lid 26 in which the capillary 1 is inserted by the above-described process. The adhesive hangs down from the opening to the end of the flared hollow electrode and flows down into the hollow electrode in which the capillary 1 is inserted.
[0045]
(7) Filling the plastic hollow electrode with filling adhesive
Vacuum suction is performed from the sample introduction end side of the plastic hollow electrode, and the filling adhesive 28 dripping onto the end of the flared hollow electrode is sucked and lowered into the hollow electrode. The gap between the plastic hollow electrode 20 and the capillary 1 is completely filled with the filling adhesive 28. By sealing the gap between the plastic hollow electrode 20 and the capillary 1 on the sample introduction end side, it is possible to avoid the sample remaining in the gap. As a result, it is possible to prevent carry-over that causes a residual sample to be mixed and cause an analysis error. The above (6) and (7) can also be implemented between (7) and (8) described later. Further, the gap between the plastic hollow electrode 20 and the capillary 1 may not be completely filled, but may be partially sealed and bonded.
[0046]
(8) Adhesion of capillary and lid
A UV adhesive 34 is applied to the opening of the lid 26 in which the capillary 1 is inserted. The capillary 1 and the lid 26 are fixed by curing with UV irradiation.
[0047]
(9) Curing of filling adhesive
The filled adhesive 28 is heated and cured. As a result, the capillary 1, the plastic hollow electrode 20, and the lid 26 are fixed. Since the plastic hollow electrode 20 contains a filler, it has better adhesiveness than a conventional SUS hollow electrode. Also, when the conductive hollow polymer 20 is coated with a conductive polymer, the adhesion is improved. It should be noted that it is desirable to cure in a state where the capillary protrudes from the sample introduction end side of the plastic hollow electrode 20. The left side of FIG. 6 shows a state immediately after the filling adhesive is cured.
[0048]
(10) Cutting of the sample introduction end side of the hollow electrode
The tip of the plastic hollow electrode 20 is cut with a rotary cutter coated with diamond powder and the capillary 1 is cut at the same time. In the case of a conventional SUS hollow electrode, the cutting surface of a rotary cutter or the like is immediately clogged with metal powder and cannot be cut. For this reason, the hollow electrode made of SUS was not cut, but only the capillary 1 was cut. However, when the hollow electrode is made of plastic, the hollow electrode and the capillary can be cut simultaneously. Thereby, the cross section of the plastic hollow electrode 20 and the cross section of the capillary 1 can be made substantially on the same plane.
[0049]
(11) Cleaning and drying of the hollow electrode
The sample introduction end manufactured by the above process is washed and dried, and the cutting powder generated at the time of cutting is removed. This completes the production of the load header 4.
[0050]
If the material of the hollow electrode is plastic as in this embodiment, it can be easily processed by heating or ultrasonic waves. Further, unlike the production of SUS hollow electrodes, a great effort such as deburring or returning during processing is unnecessary. For this reason, a hollow electrode can be produced easily.
[0051]
Hereinafter, a method for introducing a sample using a plastic hollow electrode will be described. FIG. 7 is a partial detailed cross-sectional view of the plastic hollow electrode during sample introduction.
[0052]
When the sample is introduced, the plastic hollow electrode 20 is inserted into the sample container 2 in which a small amount of the sample 32 is held. As a result, the plastic hollow electrode 20 and the sample introduction end 33 of the capillary come into contact with the sample 32. A voltage is applied to the plastic hollow electrode 20. As a result, an electric field is generated in the sample 32 as shown by the arrow in FIG. The electric field is generated from the plastic hollow electrode 20 toward the sample introduction end 33. By this electric field, charged DNA or the like contained in the sample 32 is introduced into the separation medium filled in the capillary 1.
[0053]
In this embodiment, the cross section of the plastic hollow electrode 20 and the cross section of the capillary 1 are substantially on the same plane. For this reason, if the sample introduction end 33 is in contact with the sample 32, the plastic hollow electrode 20 is also in contact with the sample 32 and the sample can be introduced. That is, the sample can be introduced without sinking the sample introduction end 33 into the sample 32 as in the prior art in which the capillary protrudes from the hollow electrode. Therefore, a very small amount of DNA sample of 10 μl or less can be introduced.
[0054]
Samples used for DNA analysis and the like are obtained by purifying cells and the like with a large number of reagents and procedures and increasing the amount of replication. For this reason, it is very expensive to obtain a large amount of samples. However, in this embodiment, it is possible to analyze a sample that can contact the sample introduction end. That is, analysis can be performed without a large amount of sample that can sink the sample introduction end. Therefore, the cost of electrophoretic analysis can be reduced.
[0055]
In this embodiment, a plastic hollow electrode is used. Since plastic is softer than capillaries, breakage of capillaries during capillary array fabrication and use can be avoided. For example, in the capillary array fabrication described above, an excessive load is applied when the capillary is inserted into the hollow electrode, and no breakage occurs even if the two are rubbed together. Also, when the capillary array is installed, no breakage occurs even if the user handles the capillaries somewhat roughly.
[0056]
[Example 2]
In this embodiment, a plastic hollow electrode is pressure-bonded to a capillary to seal a gap between them on the sample introduction end side. Although it differs from the first embodiment in that the plastic hollow electrode 20 is deformed and pressure-bonded to the capillary 1, the rest is substantially the same as the first embodiment. Hereinafter, the difference from the first embodiment will be mainly described.
[0057]
When manufacturing the capillary array in the present embodiment, the crimping process shown in FIG. 8 is performed in (6) and (7) of the first embodiment. FIG. 8A shows a state immediately before the pressure bonding, and FIG. 8B shows a state immediately after the pressure bonding.
[0058]
The squeezing jigs 31 on both sides thereof are arranged so as to sandwich the plastic hollow electrode 20 into which the capillary 1 is inserted. A mold simulating the sample introduction end side is formed inside the aperture jig 31. The drawing jig 31 is heated to sandwich the plastic hollow electrode 20. The plastic hollow electrode 20 is heat-shrinked and pressure-bonded to the capillary 1. Thereafter, the drawing jig 31 is removed and air-cooled, whereby the plastic hollow electrode is hardened in a state where the capillary is crimped. Of course, instead of heating the squeezing jig 31, the plastic hollow electrode 20 can be processed by applying ultrasonic waves. In this case, the working time can be further shortened.
[0059]
In this embodiment, the gap between the plastic hollow electrode and the capillary on the sample introduction end side can be sealed without using an adhesive. In the method using an adhesive, ions contained in the adhesive may dissolve in the sample and adversely affect electrophoresis, but this problem can be avoided. In addition, since the outer diameter on the sample introduction end side can be made thinner than that in Example 1, a smaller amount of sample can be introduced.
[0060]
[Example 3]
The present embodiment is an electrophoresis apparatus that attaches and introduces a sample to the sample introduction end. The cross section of the plastic hollow electrode 20 and the capillary 1 is flat (same surface), and a sample is directly attached thereto by a nozzle or a dispenser. FIG. 9 is a schematic diagram showing a load header. FIG. 10 is a detailed cross-sectional view of the sample introduction end. FIG. 11 is a detailed cross-sectional view showing a sample introduction end in the middle of manufacture. Hereinafter, the difference from the first and second embodiments will be mainly described.
[0061]
As shown in FIG. 9, the load header 4 of this embodiment includes seven plastic hollow electrodes 20 facing upward. At the time of sample introduction, a very small amount of sample is dropped on the sample introduction end side by a dispenser 35 and a robot (not shown). Then, a high voltage is applied by the high voltage power supply 15 to introduce the sample.
[0062]
In addition, the direction of the load header 4 at the time of electrophoresis does not ask | require. For example, as shown in FIG. 9, it may be carried out with the sample introduction end facing upward. Further, the orientation of the load header 4 may be changed as appropriate in response to a series of electrophoresis analysis steps (washing → sampling → sample uptake electrophoresis → buffering → analysis electrophoresis → washing).
[0063]
As shown in FIG. 10, the hollow electrode of the present embodiment has a flared sample introduction end, and can increase the amount of sample attached. Further, by changing the diameter of the flare portion, the amount of adhesion can be controlled without changing the capillary dimensions. Of course, the plastic hollow electrode shown in Example 1 can also be used. Note that the adhesion of the sample can be improved by subjecting the sample introduction end side to a hydrophilic treatment with acid or the like. Moreover, since the sample adhering to the sample introduction end side can be easily removed, the sample introduction end side can be effectively cleaned. For this reason, it is possible to avoid carryover when the separation medium in the capillary is refilled with a new one, and to perform highly accurate DNA analysis.
[0064]
The production of the plastic hollow electrode 20 in which the sample introduction end side is flared will be described with reference to FIG. As shown in FIG. 11, a capillary is inserted into a plastic hollow electrode 20 whose tip is processed into a flared shape. With the tip of the capillary protruding from the plastic hollow electrode 20, the gap between them is bonded with an adhesive such as epoxy. After the adhesive is cured, the plastic hollow electrode 20 and the capillary 1 are cut by a rotary cutter. For example, the hollow electrode shown in FIG. 10 can be produced by cutting at the position indicated by AB in FIG. The cutting position is determined so as to obtain a desired diameter in consideration of the amount of sample to be adhered. Further, the cut surface may be inclined in accordance with the use posture of the plastic hollow electrode 20.
[0065]
According to the present embodiment, since the sample can be introduced directly to the sample introduction end side, the electrophoresis analysis can be performed even with a very small amount of sample. For example, if the attached sample shape is a hemisphere and the outer diameter of the hollow electrode is 1 mm, it is about 0.26 μl.
[0066]
【The invention's effect】
According to the present invention, capillary breakage can be avoided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an electrophoresis apparatus.
FIG. 2 is a schematic view of a capillary array.
FIG. 3 is a schematic sectional view of a load header.
FIG. 4 is a detailed partial sectional view of a load header.
FIG. 5 is a detailed partial cross-sectional view showing flaring of a plastic hollow electrode.
FIG. 6 is a detailed partial cross-sectional view of a load header during production.
FIG. 7 is a detailed partial cross-sectional view of a plastic hollow electrode when a sample is introduced.
FIG. 8 is a detailed partial cross-sectional view showing a crimping process.
FIG. 9 is a schematic diagram of a load header in the third embodiment.
10 is a detailed cross-sectional view of a sample introduction end in Example 3. FIG.
FIG. 11 is a detailed sectional view showing a sample introduction end in the middle of manufacture.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Capillary, 2 ... Sample container, 3 ... Sample tray, 4 ... Load header, 5 ... Detection part, 6 ... Laser light source, 7 ... Mirror, 8 ... Beam splitter, 9 ... Condensing lens, 10 ... Fluorescence, 11 ... Detection lens system, 12 ... CCD camera, 13 ... buffer solution, 14 ... buffer solution container, 15 ... high voltage power supply, 16 ... separator, 17 ... capillary head, 20 ... hollow plastic electrode, 21 ... signal processing device, 23 ... Conductive rubber, 25 ... Holder, 26 ... Cover, 27 ... Adhesive, 28 ... Filling adhesive, 29 ... Flare core, 30 ... Sasae jig, 31 ... Drawing jig, 32 ... Sample, 33 ... Sample introduction end, 34 ... UV adhesive, 35 ... Despencer.

Claims (21)

An electrophoresis apparatus comprising the following configuration;
One or more capillaries having a sample introduction end capable of introducing a sample, holding a separation medium for electrophoretic separation of the sample;
A plastic electrode that has a hollow shape that can penetrate the capillary inside and holds the capillary in close contact with the capillary ;
A power source capable of applying a voltage to the current path including the sample introduction end, the sample, and the plastic electrode;
A light source for irradiating light to the separated sample;
A sensor that detects light generated from a sample. The electrophoresis apparatus according to claim 1,
The electrophoresis apparatus, wherein the plastic electrode is a plastic containing carbon nanotubes. The electrophoresis apparatus according to claim 1,
The electrophoresis device, wherein the plastic electrode is a plastic coated with a conductive polymer. The electrophoresis apparatus according to claim 3, wherein
The electrophoretic device, wherein the conductive polymer is a polypyrrole polymer or a polysilane polymer. The electrophoresis apparatus according to claim 1,
An electrophoresis apparatus in which a capillary cross section at a sample introduction end and a cross section of a plastic electrode are substantially in the same plane. The electrophoresis apparatus according to claim 1,
An electrophoresis apparatus in which a sample introduction end is formed by cutting a capillary substantially simultaneously with a plastic electrode. The electrophoresis apparatus according to claim 1,
An electrophoresis apparatus that irradiates laser light so as to propagate through a plurality of capillaries . A capillary array that can be attached to and detached from an electrophoresis apparatus, including the following configuration:
One or more capillaries having a sample introduction end capable of introducing a sample, holding a separation medium for electrophoretic separation of the sample;
A plastic electrode that has a hollow shape that can penetrate the capillary inside and holds the capillary in close contact with the capillary;
Holder for holding plastic electrodes. The capillary array according to claim 8, wherein
A capillary array, wherein the plastic electrode is a plastic containing carbon nanotubes. The capillary array according to claim 8, wherein
A capillary array in which the plastic electrode is a plastic coated with a conductive polymer. The capillary array according to claim 10, wherein
A capillary array, wherein the conductive polymer is a polypyrrole polymer or a polysilane polymer. The capillary array according to claim 8, wherein
An electrophoresis apparatus in which a capillary cross section at a sample introduction end and a cross section of a plastic electrode are substantially in the same plane. The capillary array according to claim 8, wherein
The plastic electrode has a hollow shape that can penetrate the capillary inside thereof,
A capillary array in which a sample introduction end is formed by cutting a capillary substantially simultaneously with a plastic electrode. The capillary array according to claim 8, wherein
A capillary array irradiated with laser light so as to propagate through a plurality of capillaries . A method for introducing a sample into a capillary holding an electrophoresis medium,
Hold the sample in the sample container,
It has a hollow shape that can penetrate the capillary inside, and a plastic electrode that holds the capillary in close contact with the capillary is brought into contact with the sample,
A sample introduction method for applying a voltage to a plastic electrode in a state where a sample introduction end of a capillary capable of introducing a sample is in contact with the sample. The sample introduction method according to claim 15,
A sample introduction method, wherein the plastic electrode is a plastic containing carbon nanotubes. The sample introduction method according to claim 15,
A sample introduction method, wherein the plastic electrode is a plastic coated with a conductive polymer. The sample introduction method according to claim 15,
The electrophoretic device, wherein the conductive polymer is a polypyrrole polymer or a polysilane polymer. The sample introduction method according to claim 15,
A sample introduction method in which a capillary cross section at a sample introduction end and a contact surface of a plastic electrode with a sample are substantially the same plane. The sample introduction method according to claim 18, wherein
The sample introduction method, wherein the sample introduction end is formed by cutting the capillary substantially simultaneously with the plastic electrode. The sample introduction method according to claim 15,
A sample introduction method in an electrophoresis apparatus that irradiates a laser beam so as to propagate through a plurality of capillaries .

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