JPS62247243A - Medium material for electrophoresis - Google Patents

Abstract

PURPOSE:To obtain a polyacrylamide gel film-based electrophoretic medium material using a resin film as the support with the resolution equal to or more than that of the electrophoretic medium material produced using a glass plate as the support, by providing a resin intermediate layer made of a resin material having the oxygen transmission coefficient lower than the support material between a medium layer for electrophoresis and a support layer. CONSTITUTION:A medium material for electrophoresis which includes a medium layer for electrophoresis made of a polyacrylamide-based water gel produced by crosslinked polymerization of an acrylamide-based compound and a cross linking agent in the presence of water and a resin support is provided with a resin intermediate layer made of a resin material with the oxygen transmission coefficient lower than the support material between the medium layer for electrophoresis and the support layer. The resin intermediate layer is preferably made of a resin material with the oxygen transmission of below 15cc/m<2>.atm per day in the form of a film made at a thickness of 20mum. The resin material herein applicable is a vinylidene-vinylchloride copolymer, polyvinyl alcohol or the like.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to an electrophoretic medium material, and more particularly to an electrophoretic medium material suitable for use in electrophoretic analysis of biopolymer components such as proteins. This relates to media materials for use.

[Background of the Invention] A typical embodiment of electrophoretic analysis is electrophoresis produced by coating or casting a film-forming material such as agar, cellulose, cellulose acetate, starch, silica gel, or polyacrylamide on a glass plate support. The membrane is impregnated with a buffer solution, the Th substance to be analyzed is attached to this -L, a voltage is applied to the P4 end of the support, and the membrane is developed on or inside the support (
An example of an embodiment is to carry out a single-sparrow analysis of each component of the substance by staining the sample and measuring the optical density of the dyed sample.

For details on such 'hypophoresis analysis and electrophoretic membranes, please refer to Electrophoresis Experimental Methods, ``Electrophoresis Experimental Methods (revised 5th edition in L!)'' (Bunkodo, published in 1975).

Aomizu, Nagai ed. “J!r latest electrophoresis method” (Nariyo Shoten,
Published in 1973)':9.

In recent years, electrophoresis has been frequently used to analyze biological components, and protein analysis in particular has been frequently used in biochemical tests for disease diagnosis.

Filter paper has been used as a membrane or sheet for electrophoresis for a long time, but as mentioned above, agarose membranes and polyacrylamide gel membranes have recently been used from the viewpoint of performance. Acrylamide gel membranes are currently most commonly used.

Polyacrylamide gel membranes are produced by polymerizing and crosslinking monomers such as acrylamide with a difunctional crosslinking agent such as N,N'-methylenebisacrylamide in the absence of oxygen in the presence of a polymerization catalyst. It is obtained by

Anionic surfactants are often added as denaturing agents when producing polyacrylamide gel membranes, but in the production of gel membranes for protein analysis, the amount of denaturing agent required is small, so it is added to wet gel membranes. The modifier can be impregnated into the gel film by a method of applying an aqueous modifier solution, a method of immersing the gel film in an aqueous modifier solution, or the like.

The above polymerization reaction is a radical crosslinking polymerization, and since the reaction is inhibited by the influence of oxygen, it is necessary to prepare the polyacrylamide gel film in a state where the # element is blocked. For this reason, it is now common.

A polyacrylamide gel film is produced by injecting a gel-forming solution into a cell (having a certain space, for example, about 0.3 to 1 mm thick) formed by two glass plates, and blocking out oxygen. It is cross-linked and polymerized to form a gel film.

However, since the gel film is formed between two glass plates, this method has major drawbacks such as poor handling and difficulty in mass-producing the gel film.

Electrophoresis operations using the polyacrylamide gel membrane formed as described above as an electrophoresis medium include, for example,
It is implemented as follows.

A polyacrylamide gel membrane with a sample slot provided at the upper end was placed vertically between glass plates, and after performing a pre-electrophoresis fjJ operation, a fixed amount of sample was injected into the sample slot. Next, electrophoresis is performed. After performing electrophoresis for a certain period of time, one side of the glass plate was carefully removed and immersed in a staining solution.
The electrophoretic pattern is imaged by staining the electrophoretically separated protein or its derivative 1 decomposition product.

Conventional acrylamide gel membranes used as aerophoretic media materials have problems in handling because they use glass plates as mentioned above, and experiments often fail due to the glass breaking. The development of a pneumophoresis medium material that has improved its shortcomings and is easy to handle has already been promoted.
An electrophoretic medium material has already been proposed in which a support made of a plastic material such as polyethylene terephthalate is used as a support and a polyacrylamide gel film is formed thereon.

] The electrophoretic medium material using the support made of plastic material has the advantage of being easy to manufacture and easy to handle. The present inventor has investigated in detail whether it is possible to perform electrophoresis of proteins, etc. using this electrophoretic medium material. When compared to the running media material.

It was found that there was a tendency for the resolution to decrease slightly.

[Summary of the Invention] An object of the present invention is to provide a polyacrylamide gel membrane-based electrophoretic medium material using a novel plastic film (or sheet) as a support.

The object of the present invention is particularly a polyacrylamide gel membrane-based electrophoretic medium material using a plastic film (or sheet) as a support, which is different from an electrophoretic medium material manufactured using a glass plate as a support. The object of the present invention is to provide an electrophoretic medium material that exhibits an equivalent or higher resolution.

The present invention provides an electrophoretic medium material comprising an electrophoretic medium layer made of an aqueous polyacrylamide gel formed by crosslinking an acrylamide compound and a crosslinking agent in the presence of wood, and a support made of a plastic material. A medium material for electrophoresis, characterized in that a resin intermediate layer made of a resin material having an oxygen permeability coefficient lower than that of the support material is provided between the medium layer for electrophoresis and the support layer. It consists of

[Effects of the Invention] As described above, the electrophoresis medium material of the present invention is provided with a resin intermediate layer that can reduce the permeation and diffusion of oxygen from the plastic support to the electrophoresis medium layer. Therefore, the crosslinking polymerization reaction for forming the electrophoresis medium layer (polyacrylamide gel membrane) proceeds very smoothly.
A highly homogeneous electrophoretic medium layer is formed. Therefore,
Compared to an electrophoretic medium layer formed on a plastic support layer that does not include such a resin intermediate layer, the electrophoretic medium layer of the electrophoretic medium material of the present invention has even higher resolution. show.

[Detailed Description of the Invention] The support for the electrophoresis medium material of the present invention is a sheet-like material (including a film-like material) formed from a plastic material.
It is. This plastic sheet may be made of any plastic material. Examples of preferred plastic materials include polyethylene terephthalate, polycarbonate of bisphenol A, polyvinyl chloride, polymethyl methacrylate, polyethylene, polypropylene, polystyrene, cellulose acetate, and cellulose acetate propionate.

It is preferable that the support made of plastic material has its surface made hydrophilic by a known surface activation treatment. Known methods such as ultraviolet irradiation, glow discharge treatment, corona discharge treatment, flame treatment, electron beam irradiation, chemical etching, and electrolytic etching can be applied to the surface wood-carrying treatment.

The support used generally has a thickness of about 50 to 5007 hm, preferably about 70 to 300 pm.

In electrophoresis media using plastic supports that have been proposed so far, a coating solution for forming a polyacrylamide gel is applied onto the plastic support directly or via an adhesive layer, and then a nitrogen atmosphere is applied. A cross-linking polymerization reaction is carried out below.

In the electrophoresis medium of the present invention, a resin intermediate layer made of a resin material with a low oxygen permeability coefficient is provided on a plastic support.

The resin intermediate layer marked with has an oxygen permeation rate of 15 cc/go・alIl- in the state of a film formed to a layer thickness of 20 gm.
It is preferably made of a resin material having a film thickness of 201 Lm or less, and particularly preferably a resin material having an oxygen permeation rate of 1 Occ/G·aL·day or less in a film formed to a layer thickness of 201 Lm. Examples of preferred resin materials include vinylidene chloride/vinyl chloride copolymer, polyvinyl alcohol, polyacrylonitrile, polyvinylidene chloride, vinyl alcohol/ethylene copolymer, vinylidene chloride/acrylonitrile copolymer, and acrylonitrile/methyl acrylate/butadiene copolymer. Examples include polymers. In addition, the oxygen permeation mentioned above! , :, is m o which is generally used as a measurement method for oxygen permeation.
This is a value measured by the con method.

The resin intermediate layer preferably has a layer thickness of about 0.5 to 20 μm, more preferably about 1 to 8 μm.

The acid permeation rate of the laminate consisting of the resin intermediate layer and the support is preferably 10 cc/rtf-al, m.day or less, and more preferably 7 cc/m'.at
It is particularly preferable that it is less than @·day.

1-, an electrophoretic medium layer is provided on the resin intermediate layer 4- either directly or via another intermediate layer such as an adhesive layer.

Next, the electrophoresis medium layer (hereinafter also referred to as gel medium layer, polyacrylamide gel membrane, or simply gel membrane)
I will explain about it.

Polyacrylamide gel membrane is an aqueous gel obtained by dissolving or dispersing an acrylamide compound and a crosslinking agent in water as an aqueous solution or dispersion to prepare a gel forming liquid, and then crosslinking and polymerizing both in the liquid. In this specification, unless otherwise specified, dissolution (in water) and dissolution (in water)
Both dispersion and dispersion are collectively referred to as dissolution (in water), and both aqueous solutions and aqueous dispersions are simply referred to as aqueous solutions. It also includes a mixture of an organic solvent and water, which may be added as desired as a solvent or dispersion medium.

Examples of acrylamide compounds that can be used to form polyacrylamide gel membranes include acrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-(hydroxymethyl)acrylamide,
Examples include acrylamide compounds such as diacetone acrylamide and methacrylamide compounds such as methacrylamide, and these compounds can be used alone or in combination of two or more. Among these acrylamide compounds, acrylamide is most preferred, and a combination of acrylamide and one or more of other acrylamides, Kenhokuai products, and methacrylamide compounds is also preferred.

As a crosslinking agent, rEIelectrophoresis
Known compounds (one type or a combination of two or more types) described in J 19g1.2゜220-228 etc. can be used. Examples of crosslinking agents include N,N'-methylenebisacrylamide (BIS); N,N'-propylenebisacrylamide (PBA), di(acrylamide dimethyl) ether (DAE); l,2-diacrylamide ethylene glycol. (DEG); ethylene ureabisacrylamide (EUB); ethylene diacrylate (EDA);
e: DATD); and N,N'-bisacrylycystamine (N,N'-bisacrylylylc
ysLamine.

Examples include difunctional residue compounds such as BAC).

The amount of crosslinking agent is approximately 2 to 20% based on the total weight of the body and crosslinking agent.
30 wt%, preferably in the range of about 3 to low wt%.

The gel concentration is S, 1ljerten: r
Arch.

Mouth iochem, Biophys, J I
(5upp1.), 147 (1962), the amount of monomer and crosslinking agent is approximately 3 to 30 w, based on the volume of the gel film consisting of monomer, crosslinking agent, and water. /v% range.

The electrophoresis medium material of the present invention is mainly used to advantageously analyze proteins or complex proteins (e.g. riboprotein, glycoprotein, etc.), and the electrophoresis medium layer contains an anionic surfactant as a denaturing agent. It is possible to contain an agent.

When the sample to be analyzed is a protein or a complex protein (eg, riboproteins, glycoproteins, etc.), the inclusion of an anionic surfactant is preferred or often necessary.

Of course, the anionic surfactant may not be included in the gel medium layer. For example, a gel medium layer that does not contain an anionic surfactant can be used for genetic disease diagnosis based on DNA fragment analysis or DNA analysis using restriction enzyme digestion.
It can be used for structural analysis, etc.

By incorporating an anionic surfactant into the electrophoresis medium layer, it becomes possible to efficiently separate proteins or complex proteins and measure their molecules.

Examples of anionic surfactants include alkyl sulfates, and alkyl sulfates having a long chain alkyl group having 10 or more carbon atoms are particularly preferably used. As cations that form salts, alkali metal ions such as sodium ions, potassium ions, and lithium ions are generally used, and among these, sodium ions are easier to use. Among alkyl sulfates, dodecyl sulfate (
(sodium salt, potassium salt, lithium salt, etc.) are preferred, and among them, sodium dodecyl sulfate (SDS) is most preferred. Inclusion of SDS in the gel medium layer of the present invention facilitates efficient separation of proteins or complex proteins and measurement of their molecular weights.

The content of the anionic surfactant as a modifier is in the range of about 0.05 to 2.0 w/v%, preferably about 0.1 to 1.5 w/v%, based on the gel forming solution.

The polyacrylamide gel membrane can contain a water-soluble polymer.

As the water-soluble polymer, an addition polymerization type or a reduced-to-metal type water-soluble polymer can be used.

Specific examples of addition polymerization type polymers include nonionic water-soluble polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide. 1Iiif
Specific examples of fi polymers include nonionic water-soluble polyalkylene gelcols such as polyethylene glycol and polypropylene glycol. Preferably, the water-soluble polymer has a molecular weight in the range of about 10,000 to about 1,000,000. Among these water-soluble polymers, polyethylene glycol and polyacrylamide are particularly preferred.

The water-soluble polymer is present in an amount ranging from about 2 to 100 wt%, preferably from about 5 to 50 wt% based on the total weight of monomer and crosslinker.
It is used in amounts ranging from wt%. By adding a water-soluble polymer, the polyacrylamide gel film becomes plastic, so it will not break during cutting, and the gel film also becomes plastic when drying, improving its brittleness and preventing it from breaking. This has the advantage of being less difficult. Furthermore, the viscosity of the gel film can be controlled by selecting the molecular weight and amount of the water-soluble polymer added.

The polyacrylamide gel membrane can contain agarose. The agarose is not particularly limited as long as it is a known agarose, and any of low electroosmotic, medium electroosmotic, and high electroosmotic agaroses can be used. Examples of agarose that can be used include those disclosed in Japanese Patent Application Laid-open Nos. 57-5730, 110946-1982, and Japanese Patent Publication No. 502098-1982.

Agarose is added at a rate of about 0.2 to 2 w/v%, preferably about 0.3 to 1.2 w/v%, based on the volume of the gel composition containing the mH form and the crosslinking agent. Ru. By adding agarose to the gel film, it is possible to control the solution viscosity to an appropriate level by changing the temperature of the gel forming solution, and the tli and fh properties can be stopped, and the gel film can be formed. Sometimes it has the advantage of being easier to mold.

The gel medium layer may also contain a pH buffer.

As a buffer, depending on the sample to be electrophoretically analyzed, P
It is possible to use an appropriate buffer selected from known buffering agents capable of buffering to pH 4ti within the range of H2.5 to 10.0.

The vine buffer to be used is manufactured by Chemical Society of Japan T! A “Chemistry Handbook Basic Edition” (Tokyo, Marukan ■ Published in 1966) 1312-
1320 pages: 8th Thu, Nagai ed. “Latest electrophoresis methods” (
Tokyo, Hirokaku Shoten, 1973, 320-322 pages; r Data for Biochemical
Re5searchJ (R,M.

C, Dawson cL al, ed., 2nd edition, 0xf
ord at LheClarkdon Press
, published in 1969) 476-508 pages; r
RiochemisLry J 5.467 (1
966), r Analytical Biochem
isLryJ 104. :100-:110(198
0) Buffers described in i.

Examples of buffers include barbiturate-containing buffers, tris(hydroxymethyl)aminomethane (Tris)-containing buffers, phosphate-containing buffers, borate-containing buffers, acetic acid or acetate salts. Buffers, citric acid or buffers containing citrate, lactic acid or milk #Ji! buffer containing glycine, N,N-bis(2-hydroxyethyl)glycine (Bicine), N-2-hydroxyethylpiperazine-N'-2-hydroxypropane-3-sulfone # (HEPPSO) or a salt thereof, N-2-hydroxyethylpiperazine-N'-3-
Propanesulfonic acid (EPPS) or its salt, N-[
Tris(hydroxymethyl)co-3-aminopropanesulfonic acid (TAPS) or a salt thereof, and an acid, alkali, or J'i! which is optionally combined with any of these. etc. can be mentioned. Specific examples of preferred buffers include potassium dihydrogen phosphate-disodium hydrogen phosphate, Tris/sodium borate, Tris/sodium borate/EDTAZNa salt, Tris/citric acid, sodium harbital/sodium acetate, sodium harbital/ hydrochloric acid.

Barbiturate/sodium harbital, acetic acid/sodium acetate, lactic acid/sodium lactate, citric acid/phosphoric acid disodium, Bicine.

HEPPSO, HEPPSO sodium salt, EPPS,
Examples include EPPS sodium salt, TAPS, TAPS sodium salt, and the like.

In the present invention, the polyacrylamide gel membrane is a monomer typified by acrylamide, a difunctional allyl (ally)
l) It is obtained by radical crosslinking polymerization of a monomer and a crosslinking agent in an aqueous solution in which a compound or an acrylic compound (crosslinking agent), a water-soluble polymer, and agarose are substantially uniformly dissolved. It is presumed that the water-soluble polymer and agarose are substantially dispersed in the three-dimensional cross-linked polymer formed from the body and the cross-linking agent, and the latter two polymer buttons are intertwined with the three-dimensional cross-linked polymer. Ru.

The above-mentioned radical crosslinking polymerization reaction can be caused by a known method such as the presence of peroxide and/or ultraviolet irradiation in the absence of molecular oxygen. This reaction can also be accelerated by heating and UV radiation.

As a catalyst for radical crosslinking polymerization, r Electr
.

phoresisJ 1981. 2. 213-2
19. Same 1981. 2. 220-228; Aomizu and Nagai (eds.) [Latest Electrophoresis Methods J (published in 1973), etc., known low-temperature radical polymerization initiators can be appropriately selected and used.

Specific examples of preferred radical polymerization initiators include β-dimethylaminopropionitrile (DMAPN)-beroxonisulfate ammonium mixture, N, N, N', N'
Examples include a combination of -tetramethylethylenediamine (TEMED)-beroxonisulfate mixture, TEMED-riboflavin mixture, TEMED-riboflavin-hydrogen peroxide mixture and ultraviolet irradiation. The content of the radical polymerization initiator is about 0.3 to 5% by weight, and preferably about 0.3% to 5% by weight, based on the total weight of the width h1 and the crosslinking agent.
It is in the range of 5 to 3% by weight.

The gel medium layer is formed by coating the gel forming liquid on the resin intermediate layer on the support by a known method, either directly or through another intermediate layer such as an adhesive layer, and then forming the gel. It can be formed by crosslinking and polymerizing a liquid.

When the gel-forming liquid is crosslinked and polymerized on the surface of the resin intermediate layer, the gel-forming liquid coating layer can be further covered with a covering material such as a cover film, sheet, or plate. The cover film, sheet, or plate used for this purpose may be made of the same material as the support described above, and may also have a reduced actual acid permeability like the support. The thickness of the coating material is less than 300Bm,
A practically preferred thickness range is about 4 to 200 gm, and a particularly preferred range is about 44 m to 100 gm.

The polyacrylamide gel film may contain other additives such as an antioxidant, if necessary. As the antioxidant, various compounds known to be incorporated into the gel film can be used. Specific examples of antioxidants include dithiothreitol and 2-mercaptoethanol.

Other additives include wetting agents, and the polyacrylamide gel film may contain polyol compounds such as glycerin and ethylene glycol T. The content of the polyol compound is about 5 to about 40% based on the volume of the gel membrane.
Selected from the range of w/v%. Among the polyol compounds, glycerin is particularly preferred. By incorporating a wetting agent, it is possible to prevent the gel film from drying out due to extreme water evaporation during storage, and it also improves the physical properties of the gel film, such as preventing brittleness caused by extreme dryness and preventing cracking. There is an advantage to being R.

The electrophoresis medium material of the present invention can be used in any of the water-motor type and vertical plate electrophoresis methods, disk electrophoresis methods, etc. according to the known methods described in the above-mentioned documents.

Examples of the present invention are described below.
There is no limit to the scope of

[Example 1] Thickness: 180g with surface made wood-friendly by ultraviolet irradiation treatment
M colorless and transparent polyethylene terephthalate sheet (support)
9:l) The amount of oxygen permeation in a film formed with a copolymer layer thickness of 20 pm is approximately 5 cc/m2・atm.
day) to form a resin layer with a thickness of approximately 5 pm.

The oxygen permeability 'jS coefficient of the support provided with the resin layer of letter L was 4 cc/rrf-atm·day.

On the vapor deposition layer provided on the support, acrylamide 9
．． 5g, BISo, 5g, 3.58g disodium hydrogen phosphate decahydrate, 0.33g sodium dihydrogen phosphate dihydrate, and 5DSO, 10 containing log
Add 1.3 ml of ammonium belloxonisulfate (5 m ji 1%) as a polymerization initiator to a solution of 0 mJL, TEMED.
33. The product to which u was added was coated and molded to a thickness of 0.3 mm, irradiated with a 100W high-pressure mercury lamp from a distance of 10 cm in a nitrogen atmosphere, and left to stand for 10 minutes to obtain a polyacrylamide gel film.

[Comparative Example 1] Polyethylene terephthalate sheet (support) L was coated with polyvinylidene chloride/vinyl chloride (9:1) copolymer in the same manner as in Example 1, except that a coating layer of vinylidene chloride/vinyl chloride (9:1) copolymer was not provided. An acrylamide gel was formed.

In addition, the oxygen permeability coefficient of the support described in L is 17cc/go・a
It was te-day.

[Reference Example 1] Using a glass plate instead of a polyethylene terephthalate sheet as a support, vinylidene tijide/vinyl chloride (
9.l) A polyacrylamide gel film was formed on the support in the same manner as in Example 1 except that the copolymer coating layer was not provided.

[Electrophoresis test] A sample injection port was formed in the polyacrylamide gel film prepared in 11) in Example 1, Comparative Example 1, and Reference Example 1, and then a polyethylene terephthalate sheet (cover sheet) with a thickness of 63 m was placed on the gel film. covered.

Use this polyacrylamide gel membrane! ! Separation experiments were performed by subjecting quasi-protein samples to electrophoresis.

After the electrophoresis was completed, the cover film of the gel membrane was gently peeled off and removed, and the entire gel membrane was immersed in a 0.1% Coma Sea Blue aqueous solution to stain the migration zone blue.

The migration patterns obtained with the gel membranes of Example 1 and Reference Example 1 showed high resolution and were easy to decipher. On the other hand, the resolution of the migration pattern obtained with the gel film of Comparative Example 1 was lower than that of the migration pattern obtained with the gel films of Example 1 and Reference Example 1.

In addition, the difference in migration distance between the central migration row and both side migration rows due to the smiling effect of the migration patterns obtained with the gel membranes of Example 1 and Reference Example 1 was small, but Comparative Example 1 The migration pattern obtained with the gel membrane has a central migration column due to the Smile Link effect and r+? The difference in migration distance with the side migration column was large.

[Example 2] The intermediate resin layer provided on the support was made of polyacrylonitrile (
The oxygen permeation rate of this polyacrylonitrile film formed to a layer thickness of 20 μm is approximately 2 cc/lrr'
A support having an intermediate resin layer was formed in the same manner as in Example 1, except that the layer was formed from 1101 L in thickness.

The acid permeability coefficient of the support attached to the above resin layer is 2.
c c /rn'-atm-day.

Then, a polyacrylamide gel film was formed on the intermediate resin layer of the support 7 in the same manner as in Example 1.

[Electrophoresis test] A sample injection port was formed in the polyacrylamide gel membrane obtained in Example 2, Comparative Example 1, and Reference Example 1, and then a polyethylene terephthalate sheet (cover sheet) with a thickness of 504 m was covered over the gel membrane. .

Using this polyacrylamide gel membrane, a standard protein sample was subjected to electrophoresis and a separation experiment was conducted.

After the electrophoresis run, the cover film of the gel membrane was gently removed, and the entire gel membrane was immersed in a 0.1% Comassie blue aqueous solution to dye the migration zone blue.

The migration patterns obtained with the gel membranes of Example 1 and Reference Example 1 showed high resolution and were easy to decipher. On the other hand, the resolution of the migration pattern obtained with the gel membrane of Comparative Example 1 was the same as that of Example 1 and Reference Example 1. The resolution of the electrophoretic pattern obtained with the gel membrane was low compared to that obtained with the gel membrane.

In addition, the difference in migration distance between the central electrophoresis column and the both measurement sections due to the smiling effect of the electrophoresis patterns obtained with the gel membranes of Example 1 and Reference Example 1 was small, but in the comparative example There was a large difference in the migration distance between the central electrophoresis column and both measurement sections due to the smiling effect of the electrophoresis pattern formed by the gel membrane of No. 1.

Claims (1)

[Scope of Claims] 1. An electrophoretic medium comprising an electrophoretic medium layer made of an aqueous polyacrylamide gel obtained by crosslinking and polymerizing an acrylamide compound and a crosslinking agent in the presence of water, and a support made of a plastic material. An electrophoresis material, characterized in that a resin intermediate layer made of a resin material having an oxygen permeability coefficient lower than that of the support material is provided between the electrophoresis medium layer and the support layer. medium material. 2. The electrophoretic medium material according to claim 1, wherein the resin intermediate layer has a layer thickness of 0.5 to 20 μm. 3. The resin intermediate layer has an oxygen permeation rate of 15 cc/m^2・at in the state of a film formed to a layer thickness of 20 μm.
2. The electrophoretic medium material according to claim 1, characterized in that it is made of a resin material having a particle diameter of m·day or less. 4. The resin intermediate layer is made of vinylidene chloride/vinyl chloride copolymer, polyvinyl alcohol, polyacrylonitrile, polyvinylidene chloride, vinyl alcohol/ethylene copolymer, vinylidene chloride/acrylonitrile copolymer,
and a low oxygen permeability resin material comprising acrylonitrile/methyl acrylate/butadiene copolymer. 5. The resin intermediate layer is formed by coating on the support, and the oxygen permeation rate of the laminate formed by the resin intermediate layer and the support is 10 cc/m^2・atm・day or less. The electrophoretic medium material according to claim 1, characterized in that: 6. The electrophoretic medium material according to claim 1, wherein the support made of plastic material is made of polyethylene terephthalate. 7. The electrophoresis medium material according to any one of claims 1 to 6, wherein the electrophoresis medium layer further contains a water-soluble polymer and agarose. 8. The electrophoretic medium material according to any one of claims 1 to 6, wherein the electrophoretic medium layer further contains a modifier consisting of an anionic surfactant.