JP2000146910A - Electrophoresis system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for realizing the quick and simultaneous parallel detection of electrophoresis images in electrophoresis analysis. SOLUTION: The detection of a signal to be operated by one sensor is operated by plural sensors arranged along an electrophoresis path. The electrophoresis path 3 is constituted of rectangular capillary vessels, and when an optical sensor array 1 is integrated with this, a whole electrophoresis system can be integrated into a micro-chip. Thus, the simultaneous parallel monitor of separated states can be realized, and quick electrophoresis analysis can be realized by this inexpensive and fine device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a system for performing electrophoretic analysis. In particular, the present invention relates to an electrophoresis system in which an electrophoresis unit and a detection mechanism for mechanically reading an electrophoresis result are combined.

[0002]

2. Description of the Related Art Electrophoretic analysis is a basic analytical operation indispensable for analyzing and separating biological components such as proteins and nucleic acids. Electrophoretic analysis utilizes a phenomenon in which a substance to be analyzed moves in an electric field based on a difference in charge state.
If the charge state is manipulated under various environmental conditions, not only applications such as detection and quantification of substances, but also physical properties such as molecular weight and isoelectric point can be known. Alternatively, it can be used as a means for collecting a target substance for use as a sample for another analysis operation.

[0003] Among electrophoretic analyzes, capillary electrophoresis has become popular as a new analysis technique. For the capillary, a thin tube made of silica and having an inner diameter of 10 to 100 μm and a length of 10 to 100 cm is generally used, and this is filled with a gel or various liquids as a medium. FIG. 3 shows the principle of capillary electrophoresis and the relationship between time and a signal detected by a sensor (or detector). In the electrophoretic analysis, the influence of convection caused in the electrophoresis medium by heat generation (Joule heat) due to energization greatly affects the separation result. Heat generation due to energization can be said to be a fatal limitation of electrophoretic analysis. For this reason, in the conventional electrophoretic analysis, a gel medium has been used so as not to cause convection. However, by utilizing the special condition of the inside of the capillary, heat can be dissipated effectively. In addition, the temperature can be easily controlled with a capillary as compared with a flat surface where it is difficult to maintain a uniform temperature. Taking advantage of these advantages,
Capillary electrophoresis, which does not necessarily require a gel medium, has excellent separation ability, has become widespread as an inexpensive and highly accurate analyzer.

[0004] In particular, in the analysis of isoelectric point, electrophoretic electrophoresis can be performed in a liquid, so that the migration time has been greatly reduced. In conventional gel electrophoresis, it took a long time for the protein to converge to the isoelectric point in the gel medium.

[0005] Although capillary electrophoresis has been rapidly spread and supported by many advantages, some problems remain. In a known capillary electrophoresis system, detection of a component to be analyzed is performed at one point. For example, in the case of protein detection, it is common that only one optical system for measuring absorption at 280 nm is attached near the end of the migration path. In such a configuration, the component to be analyzed cannot be detected unless it is migrated to the position where the sensor is arranged. Although the electrophoresis time of capillary electrophoresis is short, there are cases where rapid processing becomes difficult in a system that always requires electrophoresis to the sensor portion. Alternatively, depending on the charged state of the analysis target substance, a case where the electrophoresis does not reach the sensor portion may occur.

One feature of capillary electrophoresis is the presence of electroosmotic flow. Usually, the inner wall of the capillary is negatively charged and attracts cations in the running buffer. When a voltage is applied to the capillary, cations move to the cathode. At this time, since the cations move while dragging water ions, the entire solution flows to the cathode.
This flow is an offset flow that does not depend on the sample and is called an electroosmotic flow, and can be controlled to some extent by the pH of the buffer and the coating on the inner wall. Neutral samples run at the same speed as the electroosmotic flow, positively charged samples move faster, and negatively charged samples move slower.

As described above, in capillary electrophoresis, by utilizing an offset flow called an electroosmotic flow,
Positive, negative and neutral samples can be separated at once. However, in a negatively charged sample, | ν _m |> ν
_{At eof} , the sample moves to the anode side and does not reach the sensor (v _m is the velocity of the negatively charged substance, v _eof is the velocity of the electroosmotic flow). The only way to solve this problem is the largest |
It is necessary to supply an electroosmotic flow that can move a sample having ν _m | to the cathode side, but this is not always possible. Even if this was possible, a positively charged sample could reach the sensor in a short time if fast electroosmotic flow was used, making it impossible to separate two samples with similar mobility. There is. As one expression of the degree of separation, the relationship shown in Expression 1 is known.

[0008]

(Equation 1)

Here, N is the number of theoretical plates, Δν is the difference between the moving speeds of the two samples, and ν is the average value of the moving speeds of the two samples. From this, it can be seen that, in order to increase Rs as much as possible, it is necessary to decrease ν. However, increasing the electroosmotic flow increases ν, which results in undesirably decreasing Rs.

Another feature of capillary electrophoresis is that isoelectric focusing in a liquid medium can be performed quickly. However, since the protein converged to the isoelectric point cannot be detected by a sensor fixed at one point, conventionally, an operation of further electrophoretically moving the protein to the sensor has been required. In addition, in known capillary electrophoresis, since a sample can be supplied only from the end portion of the migration path, it may be long if a protein that converges to an opposite end portion in the case of isoelectric focusing becomes an analysis target component. Electrophoresis time is required. In cases where the isoelectric point cannot be predicted, it is obvious that starting electrophoresis near the center is a reasonable approach.However, due to the characteristics of the capillary, a mechanism for supplying the sample to the center near the center should be inexpensive. It is difficult.

[0011] In addition, although the heat radiation and the temperature control are facilitated by using the capillary, the current size is close to the limit due to the limitation in manufacturing the capillary. Also, in terms of operability, a thinner than the current state is liable to breakage and is not realistic. For this reason, it can be seen that the limit has been reached in terms of shortening the migration time due to downsizing, and performing high-sensitivity analysis using a smaller amount of sample.

[0012] In addition to capillary electrophoresis, new electrophoretic analysis techniques have been proposed. For example, an electrophoretic analysis using a microchannel formed on a flat substrate as an electrophoresis path has been attempted. Glass and polymers are often used for microchannels. In this method, a microchannel is used, so by combining semiconductor chips,
Can build even smaller analysis systems than capillaries
(Science, Vol.261, pp895-897, 1993; Proc. Natl. Ac
ad.Sci. USA, Vol.91, pp.11348-11352, 1994; Anal.Che
m., Vol. 69, pp. 3451-3457, 1997). However, since the signal is still detected at one point, the same problem as the capillary electrophoresis system remains. As a minute system, a system in which a detection IC is formed using a semiconductor process and a plastic flow path is formed thereon is known (I
nternational Conference oc Microelectromechanical
Systems -MEMS96-, pp.491-496,1996; International Co
nference on Solid -State Sensors and Actuators -Tr
ansducer97-, pp.503-506,1997). Application of new technologies such as stereolithography to the formation technology of plastic channels (BME, V
ol. 12, No. 4, pp. 66-75, 1998). However, as a detection system, the conventional principle of one-point detection at the outlet of a flow passage has been adopted.

As an analysis method that requires two-dimensional analysis of electrophoresis results, such as determination of the base sequence of DNA, a method of analyzing an electrophoresis pattern by scanning a capillary is known. However, such a method requires a highly accurate optical system for scanning with a minute light beam. In addition, a complicated system including a lens and a prism is required, and it is difficult to commercially supply an inexpensive device. Further, an electrophoresis system that performs detection at a plurality of positions along an electrophoresis path is also known (Japanese Patent Laid-Open No. 10-13278).
3). In the system disclosed in this prior art,
In order to achieve a high S / N ratio while performing optical measurement with a short optical path length, a certain range of signals must be integrated.
For this reason, it is a condition that the power supply is stopped after the electrophoresis is completed and the signal measurement and the data analysis are performed, so that the measurement during the electrophoresis cannot be realized. Further, optical components such as lenses are indispensable, and it is difficult to realize an inexpensive system with a complicated structure.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a signal detection principle which enables more rational and rapid separation while utilizing the characteristics of capillary electrophoresis such as rapidity and high accuracy. I have. In particular,
It is an object of the present invention to provide a novel system and analysis method for improving electrophoretic analysis, which has been variously limited by the arrangement of sensors, based on a more rational detection principle.

A second object of the present invention is to provide an inexpensive electrophoresis system that can be more easily miniaturized than currently popular capillary electrophoresis systems.

[0016]

Means for Solving the Problems The present inventors have focused on the arrangement of sensors and the physical shape of the capillary as factors limiting the possibility of electrophoretic analysis, and conducted research on a new configuration. Was. As a result, they have found that a rational detection system can be configured by providing sensors at a plurality of positions corresponding to the migration path, and completed the present invention.

Further, according to the present invention, if an optical sensor array in which fine sensors are arranged in a matrix in a plane as a plurality of sensors is used, an electrophoresis system having a very fine structure can be configured by the current processing technology. Was found. That is, the present invention relates to the following electrophoresis system and electrophoresis analysis method. [1] An electrophoresis system including at least the following components, wherein a signal can be detected by a sensor during electrophoresis. a) an electrophoresis unit for performing electrophoretic separation of a substance to be analyzed, and b) a plurality of sensors combined with the electrophoresis unit and arranged in a migration path of the substance to be analyzed to detect a signal of the substance. [2] The electrophoresis system according to [1], wherein the sensor is an optical sensor in which a plurality of detection elements are arranged on a plane. [3] The electrophoresis system according to [2], wherein an optical sensor having a plurality of detection elements arranged on a plane is integrated with the electrophoresis unit. [4] The electrophoresis system according to any one of [1] to [3], wherein migration paths in the electrophoresis unit are arranged in parallel. [5] The electrophoresis system according to [4], wherein the migration paths arranged in parallel have a single continuous capillary structure. [6] The detection element according to [4] or [5], wherein the detection element constituting the sensor detects a signal from one migration path and is not affected by a signal of an adjacent migration path arranged in parallel. Electrophoresis system. [7] The electrophoresis system according to [1], wherein an analysis target sample application site is provided at an arbitrary part of the migration path. [8] The electrophoresis system according to [7], wherein an analysis target sample application site is provided in an intermediate portion of a migration path of the electrophoresis unit.

[9] An electrophoretic analysis method including at least the following steps a) to c). a) Performing electrophoresis of the substance to be analyzed b) Using a plurality of sensors arranged at positions corresponding to the path where the substance to be analyzed is migrated by the electrophoretic separation operation, the signal of the substance is parallelized with the electrophoretic separation C) at a plurality of positions c) determining the physicochemical properties of the substance based on the signals detected at the plurality of positions and the position information at which the signals were detected.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an electrophoresis system comprises an electrophoresis unit and a sensor for detecting a signal from an electrophoresis path. The electrophoresis unit constituting the present invention includes an electrophoresis path and an energization mechanism necessary for electrophoresis. As these components, those used in known electrophoresis systems can be applied as they are. For example, an electrophoresis unit using a microchannel is an advantageous embodiment of the present invention. This electrophoresis unit has a structure in which fine grooves are arranged on a substrate and the fine grooves are covered as necessary, and liquid flows through the grooves by capillary action. Both ends of the groove are electrodes, and electrophoresis is started by connecting to a power supply. The arrangement of the grooves is arbitrary, but it is advantageous to form the grooves in a rectangular shape, since a long migration path can be formed with a small area. For example, within a 5mm x 5mm range, a 0.1mm
Effective electrophoresis length by making a rectangular shape folded at intervals
6cm can be achieved. Alternatively, a plurality of migration paths can be arranged in parallel. If the components of the electrophoresis unit are made of a material through which the signal of the substance to be analyzed can pass, the state of electrophoresis can be detected from outside the electrophoresis unit.

The microchannel has a structure in which a groove (flow path) having a cross section of about several tens to 100 μm square is provided on the surface of the substrate, and the groove is sealed with a suitable material. Etching is used to form the grooves (flow paths). The board material includes
Glass was used. Glass has excellent insulating properties and heat dissipation properties, but has disadvantages such as the use of glass or silicon, which requires high-temperature processing for sealing grooves (flow paths). Recently, molding of microchannels based on casting using materials such as silicone elastomers instead of glass has been attempted. Materials include polydimethylsiloxane (hereinafter abbreviated as PDMS, Anal.Che
m., Vol. 69, pp. 3451-3457, 1997), acrylic resin (Ana
l. Chem., Vol. 69, pp. 2626, 1997), polymethyl methacrylate (hereinafter abbreviated as PMMA, Anal. Chem., Vol. 69, pp. 478)
3, 1997). First, a master mold is prepared by etching a silicon wafer. The structure is transferred by pouring a polymer in solution into this, and the polymer is solidified. The general size of the channel can be several tens μm in depth, 10-100 μm in width, and the effective analysis length can be several tens of cm. If PDMS is used as the material, the channel can be easily sealed by natural adsorption to glass or a PDMS substrate.
The temperature required for sealing is 10 when bonding with glass
The temperature is 5 ° C and 108 ° C between PDMS, which is much lower than the bonding temperature required for a glass substrate. It has already been confirmed that electrophoretic separation of DNA fragments and the like is possible in the microchannel thus created. Microchannels using polymers are advantageous in terms of cost because they can be easily mass-produced (Bunseki August 1998, p.608-609). Also, the depth of the microchannel can be made larger than that of glass which is difficult to mold by etching.

A technique for forming a channel by etching a photosensitive glass in addition to a polymer is also known. The photosensitive glass is a silicate glass in which metal ions are added and dissolved together with a sensitizer. A metal colloid is generated by heat development upon exposure to ultraviolet light, and a crystal grows using the colloid as a nucleus. Since these crystals are easily dissolved in acid, etching can be performed by acid treatment. It is possible to provide a taper in the cross section of the flow path, or to cope with a fine and complicated shape in plan view. Microchannels may be created using this processing technique.

In addition, a microchannel can be formed by a stereolithography technique using a photocurable resin.
According to the stereolithography technique, the migration path can be formed directly on the sensor. The stereolithography technique is a technique of assuming a shape obtained by slicing a target structure into multiple layers, forming each layer by light irradiation, and sequentially stacking the layers to complete the entire structure. The step of irradiating light along the sliced shape can be automated by computer control. The laser shaping method includes irradiating a laser beam from above the resin tank and stacking the structure on a vertically movable stage, and irradiating the laser beam from below the resin tank to the bottom of the resin tank. There is a regulated liquid level method for forming and laminating each slice layer between a quartz glass plate attached to a stage and a stage. However, in these general stereolithography methods, since the resin surface is in an unregulated state when the inner surface of the flow path which is a hollow portion is formed, a rough and low-transparency surface unsuitable for optical measurement is formed. However, in the regulated liquid level method, in addition to a stage that can be moved in the vertical direction, a regulating plate for controlling the liquid surface state when producing the hollow part is used, so that the inner surface of the flow path with a smooth surface and excellent transparency is produced. can do. The optical shaping technique can freely form a shape which is impossible in principle with conventional molding techniques such as injection molding and etching. Further, according to the stereolithography technique, the distance between the sensor and the migration path can be easily reduced. Specifically, for example, when irradiating an ultraviolet curable acrylic resin with an ultraviolet laser to form a migration path, the distance between the sensor and the migration path can be made as close as possible. Shorter distances result in sharper images and higher sensitivity. In the embodiment, the distance between the sensor and the migration path is 0.5 mm by the optical shaping technique. In addition, this is not a limitation in the molding technique, but is a numerical value simply set based on a positional relationship with other parts.
Therefore, in principle, the distance between the sensor and the migration path can be further reduced.

The depth of the microchannel is an important factor that determines the optical path length. By using polymer as a material,
An optical path length of 50-100 μm can be easily realized. If the optical path length is shorter than this range, sufficient signal intensity cannot be expected especially in the case of measuring absorbance. On the other hand, when it is 100 μm or more, there is a possibility that the separation ability may be lowered due to an increase in the depth of the migration path. Therefore, the optical path length of 50-100 μm, particularly around 70 μm is a desirable optical path length particularly when the absorbance is used as a signal. In most reports on electrophoresis using microchannels on a flat substrate, detection is performed by fluorescence measurement using an excitation laser and a photomultiplier tube. In a known study on electrophoresis using a microchannel on a flat substrate, the absorption measurement is difficult because the channel is not so deep (therefore, the detection limit concentration C increases). In contrast, if a microchannel having a depth of about 70 μm, which is a desirable embodiment of the present invention, is used, an electrophoresis system having practical sensitivity can be provided. 70 μm with actual commercially available equipment
Absorbance measurement is carried out using a capillary having an inside diameter of the order. Hereinafter, the influence of the optical path length on the absorption measurement will be described in detail. First, absorbance A is defined as in Equation 2.

[0023]

(Equation 2) Here, I _in and I _out are the amount of light incident on the sample and the amount of light emitted from the sample, ε is the molar extinction coefficient, C is the molar concentration, and l is the optical path length. When the absorbance is small, the ratio of the amount of absorption of the sample to the amount of incident light can be described by Equation 3.

[0024]

(Equation 3) The detection limit is determined by the resolution of the detector. For example, 1
When a detector having V as the maximum amplitude and 1 mV as the minimum resolution is used (sufficiently feasible), A = εCl = 10 ⁻³ is the detection limit. Assuming that ε = 1 × 10 ⁴ / Mcm and l = 70 μm, the detection limit concentration can be obtained by Expression 4.

[0025]

(Equation 4) Although it depends on the molar extinction coefficient and the inner diameter of the capillary, this performance is not inferior to the detection limit capability of a commercially available device, and is a performance that can be sufficiently practically applied. However, deep etching of the glass takes time, so generally the optical path length is 10μ.
m. With such a short optical path length, the amount of optical absorption is very small and absorption measurement is difficult, and a sufficient signal intensity cannot be obtained unless fluorescence measurement or luminescence measurement is performed.

Further, by using a polymer as a material, the surface that blocks the optical path can be made flat. When a polymer is used as a material, for example, the cross section of the migration path is generally rectangular, and the surface that necessarily blocks the optical path is necessarily flat. Therefore, problems such as light scattering generated by the circular capillaries are reduced, and improvement in detection capability can be expected.

According to a particularly preferred embodiment of the present invention, as shown in the examples, the microchannel, which is an electrophoresis unit, is positioned closely above the optical sensor array to provide light collection. Optical system can be dispensed with. Although commercially available devices are provided with a detection window (about 0.2 to 0.8 mm), the size of the sensor itself corresponds to the detection window in a configuration in which the sensors are arranged along the flow path. This is about several tens of μm, but as can be seen from the above equation, the detection resolution is determined by the optical path length and does not depend on the horizontal spread, so it is particularly important to detect signals while performing electrophoresis in an array type configuration. No problem. In the present invention, conditions under which the optical system can be eliminated will be described below.

Particularly, in a migration path having a structure in which migration paths are arranged in parallel as shown in the embodiment, high precision analysis is required unless optical signals from adjacent electrophoresis paths are not picked up. Cannot be achieved. That is, a configuration is required in which one detection element detects a signal from one migration path. It is also necessary to avoid the influence of light passing between the migration paths. In such a case, an optical system for condensing light is usually employed, but in the present invention, the optical system can be omitted by bringing the detection element and the migration path close to each other. In the present invention, the distance between the detection element and the migration path is usually 1.5 mm or less, and preferably 0.1 to
By setting the thickness to 1.0 mm, more preferably 0.1 to 0.5 mm, a highly accurate analysis result can be expected. By bringing the distance closer to 0.1 mm or less, a more optically desirable state can be obtained, but insulation breakdown may occur depending on the material constituting the migration path.

Problems in optical measurement when the migration paths are arranged in parallel are roughly divided into diffraction and refraction. Light passing through the aperture spreads due to the Fresnel diffraction phenomenon. That is, the light that has passed through the migration path spreads before reaching the detection element. Light passing through a medium having a different refractive index such as liquid / resin / air is refracted at each interface.
If the sensing element surface is not perpendicular to the light, it can lead to a risk of reacting to signals that should not be picked up. Therefore, if the migration path and the detection element are brought as close as possible and the size of the detection element is reduced, the configuration is such that only the signal of one migration path is picked up without being affected by the signal from the adjacent migration path. it can. That is, in a preferred embodiment of the present invention, the plurality of sensing elements arranged at a plurality of locations on the migration path each correspond to a signal from one migration path.
There is no point in showing a general numerical value because the refractive index differs depending on the material constituting the migration path, but for example, a structure in which the detection element is in close contact with the electrophoresis unit is an ideal structure when the optical system is omitted. It can be said. Although the size of the sensing element is also affected by various conditions, the closer the sensing element is to the migration path, the more the detection element can be used, the closer to the width of the migration path. Conversely, the farther away from the migration path, the easier it is to pick up light that has been refracted or diffracted from a portion other than the migration path. Therefore, it is desirable to reduce the size of the detection element with respect to the width of the migration path. Note that if a charge integration type sensor is used as the detection element, there is no possibility that a reduction in area will lead to a decrease in sensitivity.

The spread of light due to diffraction can be predicted by a Fresnel approximation. Refraction can be calculated from the refractive index of the medium through which light passes and the angle of incidence of the light. From these numerical values, if conditions such as the distance between the migration path and the detection element or the size of the detection element are appropriately adjusted, sensitivity and accuracy can be achieved at a sufficiently practical level even without an optical system. It becomes possible.

When a sensor having a large number of sensing elements arranged in a plane, such as an optical sensor array, is employed, it is not necessary that all the sensing elements constituting the sensor correspond to the migration path. In such an embodiment,
By selectively collecting only the signal of the detection element corresponding to the migration path, an ideal detection mechanism can be realized as a result.

In the present invention, it is necessary to arrange a plurality of sensors for detecting a signal derived from the substance to be analyzed along the migration path. Moreover, the sensor constituting the present invention must be capable of detecting a signal during electrophoresis. In the present invention, arranging along an electrophoresis path means detecting a signal of the substance at a plurality of positions with respect to a region in which an analyte may move by electrophoresis in an electrophoresis unit. It means to arrange the sensors as possible. The region where the substance to be analyzed may move is, for example, the entire migration path, but in the present invention, it is not necessary to arrange the sensor so as to cover the entire migration path. At least a plurality of sensors may be arranged at arbitrary positions. However, as described later, such as an optical sensor array composed of densely arranged sensor elements,
The configuration in which the sensor element can be arranged corresponding to the entire migration path is an advantageous embodiment in various points.

Furthermore, in the present invention, a sensor capable of detecting a signal during electrophoresis means a sensor capable of detecting a signal at an arbitrary timing and at an arbitrary place even during electrophoresis. Any kind of signal can be used as long as it can be an index of the substance to be analyzed. Specifically, an optical signal is generally used, but in some cases, radioactivity or magnetic activity can be used as an index. Optical signals include such things as absorbance at a particular wavelength, refractive index, fluorescence and luminescence. Sensors for detecting these signals are known. For example, if an optical signal is to be detected, a photodiode or a phototransistor can be used.
In order to arrange a plurality of sensors along the migration path, it is preferable to assemble a plurality of sensors arranged in advance in the electrophoresis unit.

In order to realize this configuration, it is preferable to use an optical sensor array. An optical sensor array is a sensor element (phototransistor, etc.) that can extract changes in optical signals as changes in electrical signals.
Are two-dimensionally arranged electronic components.
Since each sensor element independently detects a signal, by comparing the obtained signal with its position information, it is possible to know at which position the signal was detected. In the present invention, the correspondence between the signal intensity during electrophoresis that can be obtained by the present invention and the position information at which the signal intensity is detected is called an image in the present invention. The image can be further superimposed with information on the transition of the signal intensity over time and displayed on a graph such as that shown in FIG. If the sensor elements constituting the optical sensor array used in the present invention are made finer and integrated in a small area, the entire optical sensor array can be formed into a microchip.

Such an electronic component is a CCD (Charged Coup)
led Device) and CMOS (Complementary Metal Oxide Semicon)
ductor) Commercially supplied as image sensors and the like. CCDs are also called semiconductor image sensors and the like, and are the mainstream of image sensors used in video cameras. On the other hand, the CMOS image sensor discharges the parasitic capacitance for a certain period of time based on the output signal of the photodiode, and then reads the parasitic capacitance. It has features such as sensitivity adjustment, low power consumption, and integration not only of sensor elements but also of peripheral circuits, and is attracting attention as a new image sensor. From among these devices, the signals to be detected,
It is appropriately selected in consideration of conditions such as sensitivity, integration degree, and size. That is, the electrophoresis unit to be combined has a shape capable of disposing a sensor element at a position along a path along which an analyte is migrated, and has a performance capable of detecting a signal caused by the analyte with appropriate sensitivity. Just choose an optical sensor array. For example, when a rectangular microchannel as shown in FIG. 1 is used for an electrophoresis unit, it is desirable to arrange the sensor element so that the microchannel can be observed with a certain resolution. At this time, if the sensor elements are more densely arranged with respect to the microchannel, there is no need to strictly define the positional relationship between the two. This is because as long as the migration path is located in a certain area where the sensor elements are arranged, it can be captured by any one of the sensor elements. By using a sensor array in which sensor elements are densely arranged, a system that does not require strict positioning with the electrophoresis unit can be provided. In such a system, it is advantageous that only the electrophoresis unit can be easily replaced.

For example, when detecting a fluorescence signal, an optical sensor array having a phototransistor arranged as a sensor element is used, and excitation light is guided from a light source having a specific wavelength. Irradiation with the excitation light may be performed by simultaneously irradiating the entire optical sensor array, or a method of scanning with a point-like or linear light source may be employed. Alternatively, if the absorbance at a specific wavelength is used as a signal, light of a specific wavelength is also emitted, and the absorption is detected by a sensor element.

By utilizing an optical sensor array, the relative positional relationship between the individual sensor elements can be kept strictly constant. This is because the sensor elements on the optical sensor array are fixed on the substrate.
In addition, since the optical sensor array is an electronic component that can be mass-produced, the cost can be kept low. Therefore, even if many sensors are used, it is economical.

In addition to the optical detection method, thermo-optical detection, electrochemical detection, electrical conductivity detection, and the like can be applied. Thermo-optical detection is an application of measurement to a phenomenon in which, when a sample component is irradiated with a laser, the temperature near the component rises locally and the refractive index changes. Changes in the refractive index can be detected by another laser. In the electrochemical detection, electrolysis is caused using two electrodes, and a component to be analyzed is measured based on an oxidation current or a reduction current at this time. In the electric conductivity detection, two electrodes are arranged in a capillary, and the electric resistance between the electrodes, that is, the electric conductivity of the sample is measured. If the sample component is ionic, the electrical conductivity is proportional to the ion concentration.

In a preferred aspect of the present invention, the electrophoresis unit and a plurality of sensors are integrated.
The term “integration” in the present invention means fixing of a relative positional relationship between the two. In this case, although it depends on the combination of the signal to be detected and the sensor, it is generally advantageous to bring them as close as possible in terms of noise and sensitivity. In particular, when an optical signal is detected by an optical sensor array, a result having a better S / N ratio can be obtained when image information is configured based on the signal of the sensor element. The integration may be performed at least when the detection is performed by the sensor. Therefore, for example, it is also possible to adopt a configuration in which the two are separably integrated, and after electrophoresis, only the electrophoresis unit is replaced and the sensor portion is repeatedly used.

Various functions necessary for electrophoretic analysis can be added to the electrophoretic system configured according to the present invention. For example, automation can be achieved by equipping the electrophoresis unit with a mechanism for supplying a sample. In order to perform the operation of supplying a sample to a minute electrophoresis path such as a microchannel by a manual technique, an operation under a microscope is required. This operation can be omitted by automation. As a means for supplying a sample to a fine migration path, for example, an electrophoretic mass transport technique can be adopted. FIG. 9 shows an example of the sample supply means.
That is, an electrophoresis path for supplying a sample is formed in which an arbitrary part of the microchannel (electrophoresis path for separation) is used as the migration path. At the end of the electrophoresis path, an electrode is connected for contact with the solution containing the sample, and at the same time, for energization with the other end. When a current is supplied in this state, the sample solution starts to move electrophoretically and is eventually guided into the microchannel. When the required amount of the sample solution is transferred into the microchannel, the electrophoresis for supplying the sample is stopped, and the electrophoresis for separation on the microchannel side may be started. According to the sample introduction method based on this principle, the sample introduction can be performed in an open system in which all the flow paths are open (that is, an opening / closing valve is not required). High accuracy can be achieved.

The sample supply means shown here can be provided at any part of the microchannel. In capillary electrophoresis, it was common to supply a sample to the end of the capillary. However, in the present invention,
For example, a sample supply means can be provided in an intermediate portion of the microchannel. Here, the intermediate portion does not necessarily mean a true intermediate point of the microchannel. Even if the position is deviated from the true midpoint, it should be understood as an intermediate portion unless it is at the end. By supplying the sample in the vicinity of the center and detecting the movement of the component to be analyzed by a plurality of sensors, the detection can always be performed by the sensors regardless of whether the sample is positively or negatively charged. Further, from the viewpoint of increasing the degree of separation, a sample is introduced from the center in a state where the electroosmotic flow is suppressed as much as possible (that is, with ν in the above formula 1 reduced), and separation is performed based on only the movement of the charge of the sample. That is, the ideal analysis conditions can be realized.

In order to actually analyze a substance by using the electrophoresis system according to the present invention having the above-described configuration, a substance to be analyzed is introduced into the electrophoresis unit, and the signal thereof is subjected to electrophoresis while the electrophoresis is performed. Tracking by sensors located along According to the present invention, it is possible to observe the output of the sensor while performing the electrophoresis, or to perform the sensing after the electrophoresis is completed if it is not necessary. In the present invention, various variations are made possible by detecting the substance to be analyzed at a plurality of positions with respect to the electrophoresis unit. Hereinafter, a particularly advantageous embodiment of the known electrophoresis system will be specifically described.

One type of electrophoresis analysis that can be particularly advantageously performed in the present invention is isoelectric focusing.
FIG. 2 schematically shows a comparison between the conventional method of detecting a signal with a single sensor and the present invention using a plurality of sensors. Isoelectric focusing is an analytical method that utilizes the phenomenon that proteins converge at a position corresponding to their charge in a pH gradient. Therefore, in principle, it is impossible to know at which position the signal of the protein may be detected before performing the electrophoresis. In a preferred embodiment of the present invention, monitoring at a plurality of positions on the migration path can be performed by the optical sensor array, so that a signal can be reliably detected regardless of where the migration is performed. Further, since the state of the electrophoresis can be monitored while performing the electrophoresis, it is an advantage of the present invention that the end of the electrophoresis can be quickly determined. On the other hand, in the conventional isoelectric focusing, it was necessary to take a sufficient electrophoresis time to surely converge to the isoelectric point. An advantage of applying the present invention to isoelectric focusing is that the starting position of electrophoresis can be freely selected. That is, when the above-described microchannel is employed in the electrophoresis unit, electrophoresis can be started from the center thereof. Since isoelectric focusing is performed on a substance whose charge is unknown, it is very reasonable to start electrophoresis from the central point of electrolysis. By the introduction method from the vicinity of the center of the sample, the charge of the component to be analyzed is not particularly limited, and electrophoresis with high resolution can be performed.

The signals detected by the optical sensor array can be processed in any manner according to the purpose of the analysis.
For example, a substance is identified by comparing the mobility of a component to be analyzed in a microchannel with a standard sample, and a quantitative value can be obtained based on the signal intensity. When obtaining a quantitative numerical value, not only the signal intensity but also the area information of the obtained signal is reflected. According to the present invention in which data of a plurality of sensor elements can be collected even during electrophoresis, collection of area information is easy.

FIG. 1 shows a preferred embodiment of the present invention. Hereinafter, an embodiment of the present invention will be specifically described based on this drawing. FIG. 1 shows an electrophoresis system according to the present invention in which an optical sensor array (1) and an electrophoresis unit (2) using microchannels are combined. Both can be integrated by means capable of fixing the mutual positional relationship. On the electrophoresis unit (2), one electrophoresis path (3) by a microchannel is installed in a rectangular shape, and constitutes one continuous electrophoresis path. The individual optical sensor elements constituting the optical sensor array (1) are fixed on a substrate, and output signals corresponding to optical signals at the positions of the sensor elements independently of each other. The optical sensor array has optical sensor elements fixed on its surface arranged along the turn-back interval of the migration path (3), and is arranged so that optical signals can be detected at a plurality of sites.

On the other hand, the end of the migration path (3) is connected to a buffer solution tank (4), and an electrode (6) connected to a power supply (5) is immersed in the buffer solution tank (4). Further, a sample introduction means for introducing a sample to be subjected to electrophoresis is provided in the migration path (3).
(7) is connected. The sample introducing means (7) itself constitutes an independent electrophoresis path, and the migration path overlaps a part of the migration path of the microchannel. The sample solution is in contact with the end of the sample introduction means (7),
By applying electricity, the sample solution is electrophoretically moved to a portion shared with the microchannel. When the transfer of the required amount of the sample is completed, the electrophoresis for supplying the sample is stopped, and the original electrophoretic analysis in the microchannel may be performed again. A series of movements of the sample solution in the sample supply means using electrophoresis are as shown in FIG. In addition, such a liquid sending system using electrophoresis can be applied not only to introduction of a sample but also to washing of an electrophoresis path.

In the electrophoresis system according to the present invention shown in FIG. 1, since the optical sensor array (1) can be integrated with the electrophoresis unit (2), both can be integrated at the start of electrophoresis. Thus, the state of separation of the sample can be optically tracked even during electrophoresis. It is possible to observe the state of the separation and immediately stop the operation if it is determined that the electrophoretic separation has been completed. It is not necessary to perform electrophoretic separation for a long time in order to expect reliable separation. Alternatively, it is also possible to prevent a trouble such that a part of the band moves to the end of the electrophoresis path and becomes inseparable due to excessive electrophoresis time.

The electrophoresis system or the electrophoresis analysis method according to the present invention can be applied in a wide range as a general-purpose electrophoresis analysis technique. In particular, it is particularly effective when a large amount of specimens must be promptly processed at low cost. For example, the analysis of glycated hemoglobin (HbA1c) in blood, which is a diagnostic indicator of diabetes, is an analysis item that is expected to require a large number of samples for disease management and screening in the aging society. is there. At present, liquid chromatography and electrophoresis analysis are required to analyze glycated hemoglobin with high accuracy, so the electrophoresis system of the present invention, which can perform the analysis at low cost and quickly, is useful. It is. More specifically, a very small amount of blood is collected from a subject using a micro blood collection device and mixed with a hemolysis buffer to prepare a sample for electrophoretic analysis. The trace amount of blood may be collected not only by a special blood collection device but also by a simple method such as filter paper blood collection. The obtained hemolyzed sample is introduced into the microchannel of the electrophoresis system according to the present invention, which is filled with an appropriate buffer, by the above-described electrophoretic sample introduction method. This is electrophoresed to analyze glycated hemoglobin. The signal for tracking the test substance may be the absorbance of hemoglobin. By electrophoresis, normal hemoglobin and glycated hemoglobin are separated, and the ratio between them can be determined.
According to the present invention, since the microchannel can be replaced, if only the electrophoresis unit is replaced as needed and the sensor array portion is repeatedly used, the running cost can be reduced. Hereinafter, the present invention will be described more specifically based on examples.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preparation of Electrophoresis Analysis System According to the Present Invention An electrophoresis system according to the present invention having the structure shown in FIG. 1 was prepared. As the electrophoresis unit, a substrate in which a microchannel was formed by etching a photosensitive glass and a glass seal was applied was prepared. On the other hand, the optical sensor array was created using CMOS technology.

1-1. Electrophoresis unit 70 μm width x 70 depth on a 7.342 mm x 14.537 mm photosensitive glass
μm micro channel is 5.57mm × 3.23mm as shown in Fig.5
An electrophoresis unit arranged in a rectangular shape within the range was prepared. First, a mask for exposing a pattern having a desired shape was applied to the surface of the photosensitive glass and irradiated with ultraviolet rays. Next, the photosensitive glass substrate was developed (heat-treated) and further re-exposed to ultraviolet light. The portion which has not been irradiated with the first ultraviolet ray by the heat treatment is not exposed. The re-exposed glass substrate was treated with acid to dissolve the UV-irradiated portion, and further heated to crystallize. Thus, the glass substrate on which the microchannel was formed in the desired pattern was glass-sealed and integrated by heating. At this time, capillaries were attached to the end portion of the microchannel and the end of the sample supply means as an interface with the outside, to form an electrophoresis unit.

1-2. Optical sensor array p + np type photosensitive phototransistor (68μm × 39μm)
4.6m at 117μm intervals both vertically and horizontally on a silicon wafer
A sensor portion (right in FIG. 6) composed of a pixel array of 30 rows × 48 columns was arranged in an area of m × 6.8 mm. This sensor part was further mounted on a base chip provided with terminals for power supply and signal output to form an optical sensor array unit (FIG. 6, left). The electrophoresis unit was placed on the obtained optical sensor array unit and fixed with an adhesive to obtain an electrophoresis system according to the present invention (FIG. 4). The positional relationship between the two was, as shown in FIG.
m, the gap between the sensor surface and the back surface of the glass substrate is 0.5 mm, and there is a gap of 1.5 mm as a whole. Also, when viewed in a plane,
The microchannels of the electrophoresis unit are located exactly every third sensor element.

2. Optical Recognition of Electrophoresis Path In the electrophoresis system according to the present invention, it was confirmed how a signal was detected. First, a borate buffer solution (transparent) was filled in a migration path composed of microchannels using a capillary. The front surface of the electrophoresis unit was irradiated with a halogen lamp as a light source (8), and the output signal (mV) of the optical sensor array was recorded. FIG. 7 shows an image formed from the output signals of the optical sensor array. The signal in the portion corresponding to the migration path is seen as black. The borate buffer is transparent, but is black because light scattering occurs on the surface of the glass material as the migration path is formed. Black lines appear at every third line, which clearly shows that they correspond to microchannels. If an optical signal is to be detected below the migration path, it is generally not preferable that this part be dark. However, in the present invention, since the optical sensor and the migration path are close to each other as described above, the image of the migration path can be detected without the aid of an optical component such as a lens.

In order to construct an image from the output signal of the optical sensor array, the following processing was performed. Each pixel that makes up the optical sensor array has
A phototransistor is provided for photoelectric conversion, and outputs a current proportional to the amount of incident light. In order to sequentially output the current from each pixel, a shift register array is arranged in each of the x direction and the y direction so that only one pixel always provides an output signal. That is, by driving the two shift register columns at appropriate timing, the signal of each pixel can be obtained in order.
More specifically, the optical sensor array used in this example has 30 rows × 48 columns of pixels. Therefore, 1
Each time a signal corresponding to 48 columns is obtained per row, a trigger signal indicating that a transition to the next row should be issued. After converting the obtained current output from the sensor into a voltage, A / D conversion was performed based on a control signal from the sensor, and data was input to a computer and reconstructed as two-dimensional data.

3. Sample concentration and sensor detection signal In the electrophoresis system according to the present invention, instead of borate buffer, 0-25 mg / mL blue dextran (blue, having an absorption maximum of 610 nm) is filled in the electrophoresis path as a model and an optical sensor array is formed. The change in the output signal was observed. The difference between the output signal (mV) of the optical sensor array at each concentration and the output signal (mV) when the buffer was filled with the borate buffer was averaged to see the relationship between the two. The results are shown in FIG. The output signal of the optical sensor array changed depending on the concentration of blue dextran, confirming that the electrophoresis system according to the present invention enables quantitative analysis.

4. Sample Movement Detected by Optical Sensor Array It was confirmed that the electrophoresis system according to the present invention can track the movement of the analyte in the migration path in parallel with the electrophoresis. The blue dextran introduced into the migration path filled with borate buffer was migrated, and an image was constructed based on the output signal of the optical sensor array. Blue dextran was electrophoretically introduced into the migration path. The principle of sample introduction at this time is shown in FIG. That is, a sample introduction migration path which is continuous with the sample tank (blue dextran) -migration path-anode tank is configured (FIG. 9-1), and electricity is supplied between the sample tank / anode tank to move the blue dextran electrophoretically. And introduced into the migration path (FIG. 9-2).
In this state, if electricity is supplied to the original electrophoresis path, the introduced blue dextran starts to move by electrophoresis (FIG. 9).
-3, Fig. 9-4). The change of the output signal at this time was recorded at intervals of 7 seconds.

FIG. 10 shows an image formed from the output signals of the optical sensor array according to the movement of the blue dextran. The position of Blue Dextran turns black,
It was confirmed that the sample moved with the migration time. According to the present invention, it is possible to simultaneously track the movement of the analyte in the electrophoresis path in parallel.

5. Improvement of electrophoresis chip using micro flow channel made of photosensitive glass 5-1. Improvement of photosensitive glass The shape of the flow channel is the same as that described in Example 1. However, the thickness of the glass at the bottom was 0.4 mm. The distance from the flow path to the sensor is 830 μm due to the thinner glass at the bottom
(0.83 mm). Due to the manufacturing process, white turbidity is seen in the part corresponding to the bottom of the flow path in the bottom glass, but this time the thickness of this part has been reduced from 0.93 mm to 0.33 mm, so that a clearer image can be obtained.

5-2. Improvement of Optical Sensor Array The optical sensor array described in Example 1 was improved as follows. Number of pixels: 147 × 147 Size of one pixel: 39 μm × 39 μm Photoelectric conversion method: Charge integration method using photodiode Absorbance detection limit: 0.0012 One pixel is smaller than the phototransistor sensor described in Example 1. In addition, the detection limit of the absorbance was reduced by reducing the noise. This is due to the use of a kind of integral type photoelectric conversion method in which a photodiode generates a current generated by light irradiation in a parasitic capacitance.

5-3. Electrophoresis Experiment A microchannel was prepared using photosensitive glass, and an integrated electrophoresis chip was prepared by bonding the microchannel to an optical sensor (FIG. 11). In this improved electrophoresis system, it was confirmed that the movement of a single substance by electrophoresis can be detected in parallel with electrophoresis. As a sample, 4.9 nl proof dextran (25 mg / ml) was filled in the migration path, and the change in the output signal of the optical sensor array was observed (FIG. 12). The buffer used was a 50 mM phosphate buffer (pH 7). The detection wavelength was 620 nm and the applied voltage was 50 V / cm. As a result, it was possible to clearly detect how the sample moved as a spot. The detection was carried out using an absorption method. The moving speed was about 0.1 mm / sec.

6. 6. Electrophoresis system using microchannel fabricated by stereolithography 6-1. FIG. 13 shows a design drawing of the electrophoresis chip, and FIG. 14 shows a photograph of the produced chip. A method called stereolithography (a method in which a resin is cured one layer at a time by laser irradiation and scanning to create a three-dimensional shape, electric processing technology 21 [68], p8-12, 1997) and acrylic on the sensor A resin flow path was directly produced. The channel has a cross-sectional shape of 100 μm × 100 μm and an effective length of 4.5 cm. Since it was fabricated directly on the sensor, the distance between the flow path and the sensor surface could be reduced to 0.5 mm. Further, the transparency of the acrylic resin is very high, and a good image is expected. Note that a 147 × 147 pixel sensor was used as the optical sensor.

6-2. Electrophoresis experiments Two blue molecular weight markers (lactate dehydrogenase (molecular weight 39,000) and β-galactosidase (molecular weight 116,000), both at a concentration of 10 mg / ml) were used as samples, and the gel buffer was ethylene glycol and Tris buffer. A mixture was used. Detection wavelength is 620nm, applied voltage is 1
The test was performed at 8 V / cm. As a result of the electrophoresis experiment, it was confirmed that the two samples migrated on the two-dimensional image and separated over time (FIG. 15). FIG. 16 shows an electrophoresis pattern one-dimensionally reconstructed along the flow path.

[0062]

According to the present invention, the progress of electrophoretic analysis can be tracked quickly and in parallel. For example, when the present invention is applied to microchannel electrophoresis, the signal of a substance to be analyzed can be traced even immediately after the start of electrophoresis. If the separation can be confirmed within a short migration time, the migration can be completed at that time. On the other hand, in a known system that performs detection only at one location, no information on the migration result can be obtained unless the analyte is migrated to the location where the signal detection mechanism is located. In particular, when applied to isoelectric focusing, an electrophoresis can be started from the center of the pH gradient and a reasonable analysis system capable of constantly monitoring the movement of the substance to be analyzed thereafter can be provided. In the isoelectric focusing electrophoresis analysis according to the present invention, rapid analysis is possible because the convergence state of the protein can be continuously monitored. Further, the combination with the sample introduction means from the central part of the migration path enables detection independent of the charged state of the component to be analyzed.

In the embodiment of the present invention in which a plurality of sensors are formed as an optical sensor array, signals can be detected two-dimensionally, and at the same time, the plurality of sensors can be easily and inexpensively integrated with the electrophoresis unit. can do. Furthermore, by forming the electrophoresis unit integrated with the optical sensor array into a single capillary structure arranged in a rectangular shape on a plane, the entire system can be integrated on a small chip. This chip functions as a rapid electrophoresis system for trace samples.

In addition, according to the present invention, a very simple optical system in which the sensor array is disposed immediately below the electrophoresis unit can be provided. At this time, an expensive optical system such as a lens is unnecessary. Also, precise processing is not required. Therefore, the cost of the electrophoresis system is reduced. In particular, in a mode in which a microchannel is used for the electrophoresis unit, an optical system excellent in reliability is realized because a capillary that causes light scattering that affects the absorbance measurement is not used.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an integrated microelectrophoresis system according to the present invention. Optical sensor array (1)
The electrophoresis unit (2) is integrated.

FIG. 2 is a schematic diagram showing advantages that can be expected by combining a plurality of sensors according to the present invention.

FIG. 3 is a schematic view showing the principle of capillary electrophoresis.

FIG. 4 is a photograph of an integrated microelectrophoresis system according to the present invention.

FIG. 5 is a photograph of an electrophoresis unit constituting the integrated micro electrophoresis system according to the present invention and a cross-sectional view thereof.

FIG. 6 is an enlarged image of an optical sensor array unit constituting an integrated micro electrophoresis system according to the present invention and its sensor portion.

FIG. 7 is an image composed of output signals of an optical sensor array when an electrophoresis unit is filled with a borate buffer.

FIG. 8 is a graph showing a change in an output signal of the integrated microelectrophoresis system according to the present invention when 0-25 mg / mL blue dextran is introduced. The vertical axis indicates (average output signal of the entire optical sensor array when the borate buffer is filled)-(average output signal of the entire optical sensor array when the blue dextran is filled) mV, and the horizontal axis indicates Indicates a blue dextran concentration (mg / mL).

FIG. 9 is a schematic diagram showing a procedure for electrophoretically introducing a sample into the integrated microelectrophoresis system according to the present invention.

FIG. 10 shows the results of electrophoresis of blue dextran.
5 is a temporal change of an image formed from output signals of the integrated micro electrophoresis system according to the present invention.

FIG. 11 is a diagram showing a configuration of an improved electrophoresis chip according to the present invention. It consists of a microchannel made of photosensitive glass and an optical sensor.

FIG. 12 shows the results of electrophoresis of blue dextran.
FIG. 5 is a time-dependent change of an image composed of output signals of the improved microelectrophoresis system according to the present invention.

FIG. 13 is a diagram illustrating a configuration of an electrophoresis chip using a microchannel manufactured by an optical shaping method. (A) is a design diagram of a flow channel, and (b) is a cross-sectional view of an electrophoresis chip.

FIG. 14 is a photograph of an electrophoresis chip manufactured by a stereolithography method. (A) is an overall view, (b) is an enlarged view of a flow path portion, (c)
It is an enlarged view of a sample injection part.

FIG. 15 shows the results of electrophoresis of molecular weight markers.

FIG. 16 is a diagram showing an electrophoresis pattern reconstructed along a flow channel. The horizontal axis represents the pixel position, and the vertical axis represents the absorbance.

[Explanation of symbols]

 (1) Optical sensor array (2) Electrophoresis unit (3) Electrophoresis path (4) Buffer solution tank (5) Power supply (6) Electrode (7) Sample introduction means (8) Light source

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 27/26 331E

Claims (9)

[Claims] An electrophoresis system comprising at least the following configuration, wherein a signal can be detected by a sensor during electrophoresis. a) an electrophoresis unit for performing electrophoretic separation of a substance to be analyzed, and b) a plurality of sensors combined with the electrophoresis unit and arranged in a migration path of the substance to be analyzed to detect a signal of the substance. 2. The electrophoresis system according to claim 1, wherein the sensor is an optical sensor having a plurality of sensing elements arranged on a plane. 3. The electrophoresis system according to claim 2, wherein an optical sensor having a plurality of detection elements arranged on a plane is integrated with the electrophoresis unit. 4. An electrophoresis path in the electrophoresis unit,
The electrophoresis system according to any one of claims 1 to 3, which is arranged in parallel. 5. The electrophoresis system according to claim 4, wherein the migration paths arranged in parallel have a single continuous capillary structure. 6. The sensor according to claim 4, wherein the detection element constituting the sensor detects a signal from one migration path, and is not affected by a signal of an adjacent migration path arranged in parallel. Electrophoresis system. 7. The electrophoresis system according to claim 1, wherein an analysis sample application site is provided at an arbitrary part of the migration path. 8. The electrophoresis system according to claim 7, wherein an analysis target sample application site is provided at an intermediate portion of a migration path of the electrophoresis unit. 9. An electrophoretic analysis method comprising at least the following steps a) to c). a) Performing electrophoresis of the substance to be analyzed b) Using a plurality of sensors arranged at positions corresponding to the path where the substance to be analyzed is migrated by the electrophoretic separation operation, the signal of the substance is parallelized with the electrophoretic separation C) at a plurality of positions c) determining the physicochemical properties of the substance based on the signals detected at the plurality of positions and information on the positions at which the signals are detected.