ELECTRODE AND ELECTRODE KIT

An object is to provide an electrode that is easily arranged at a predetermined position when electroporation is performed. The object is achieved by an electrode used for performing electroporation, the electrode includes: at least two or more conductors; and a member configured to hold each conductor and expose at least one end of each of the conductors to outside, the member has a first face where the one end of each of the conductors is exposed, and at least one or more protruding parts provided to the first face, and the length by which the one or more protruding parts protrude in an axis direction from the first face is longer than the length by which the one end of each of the conductors is exposed from the first face.

TECHNICAL FIELD

The disclosure in the present application relates to an electrode and an electrode kit.

BACKGROUND ART

Methods to introduce a biological substance such as a nucleic acid molecule (such as DNA and RNA) or a protein, a compound serving as an active ingredient of a drug, or the like into target cells as a foreign substance have been widely developed. In particular, gene transfer technologies to introduce a nucleic acid molecule into cells are basic technologies in genetic engineering. Thus, the gene transfer technologies are needed in wide range of fields such as genetically modified crops, gene therapy, genome analysis, genome editing technology, and the like.

Schemes of gene transfer technologies can be classified into biological schemes, chemical schemes, and physical schemes. Among other things, the physical schemes have an advantage that it is less required to take toxicity to cells into consideration than the biological schemes and the chemical schemes and there is no limitation of applicable cells. In particular, an electroporation method is a scheme that is the most versatile and widespread in the physical schemes.

In general electroporation, a cell suspension is put into a cuvette in which two plate electrodes are arranged, and electric pulses are applied thereto. Thus, when introducing molecules into adherent cells, processes of detaching cells from a substrate or the like to prepare the cell suspension, applying an electric field to the cells, and then re-seeding the cells to the substrate or the like to cultivate the cells are performed. However, enzyme treatment with trypsin or the like for detaching cells may cause damage to a protein and a cytoskeleton present on the cell membrane or the cell membrane surface. Accordingly, to avoid damage to cells due to detachment, an electrode with legs to perform electroporation without detaching adherent cells from a substrate or the like has been developed as disclosed in Patent Literature 1.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In the electroporation on adherent cells disclosed in Patent Literature 1, electrodes with legs are arranged on cells cultured on a plate, and electric pulses are applied to perform electroporation with the cells being adhered.FIG.8illustrates a conventional electrode with legs.FIG.8Aillustrates the whole electrode with legs.FIG.8Billustrates a schematic diagram of a side face of the tip of the electrode with legs when viewed from front.FIG.8Cillustrates a schematic diagram of the bottom face of the electrode with legs when viewed from front. In the electrode with legs, a conductor81is coated with an insulator82made of epoxy or the like, and the conductor81is exposed at the tip. Further, the electrode with legs has legs83at the tip. Because the electrode with legs has the legs83, cells adhered to a substrate or the like and the conductor81can be maintained at a constant distance, and electroporation can be performed without the conductor81being in contact with the cells. However, while the electrode with legs does not cause contact between the conductor81and the cells, the portion of the legs83in contact with the substrate or the like is small. Thus, when the electrode with legs is arranged in contact with the substrate or the like, the electrode with legs is likely to be unsettled, and this makes it difficult to maintain the electrode with legs at a predetermined position. Therefore, when an electrode with legs is used, since it is difficult to maintain the electrode with legs (conductor81) at a predetermined position, the distance between the conductor81and the substrate to which cells are adhered is unstable for each experiment, and this causes a problem of difficulty in performing electroporation in the same condition.

Accordingly, an object of the disclosure in the present application is to provide an electrode and an electrode kit that can be easily arranged at a predetermined position. Other optional, additional advantageous effects of the disclosure in the present application will be apparent in embodiments of the present invention.

Solution to Problem

(1) An electrode used for performing electroporation, the electrode comprising:at least two or more conductors; anda member configured to hold each conductor and expose at least one end of each of the conductors to outside,wherein the member hasa first face where the one end of each of the conductors is exposed, andat least one or more protruding parts provided to the first face, andwherein the length by which the one or more protruding parts protrude in an axis direction from the first face is longer than the length by which the one end of each of the conductors is exposed from the first face.

(2) The electrode according to (1) above, wherein the one or more protruding parts comprise two or more protruding parts, and the two or more protruding parts are spaced apart from each other.

(3) The electrode according to (2) above, wherein when, in an outer circumferential portion of the first face, a portion interposed between virtual lines extending from the conductors facing each other is defined as an outer circumferential virtual region,a clearance, which is provided by the protruding parts being spaced apart from each other, and the outer circumferential virtual region at least partially overlap each other.

(4) The electrode according to (1) above, wherein a slope part is provided to the first face.

(5) The electrode according to (2) above, wherein a slope part is provided to the first face.

(6) The electrode according to (3) above, wherein a slope part is provided to the first face.

(7) The electrode according to any one of (1) to (6) above, wherein the one or more protruding parts are arranged on the outer circumferential side from each of the conductors exposed in the first face.

(8) The electrode according to any one of (1) to (6) above,wherein the member has a through hole and/or a recess in the first face,wherein the through hole penetrates between the first face and a face other than the first face, andwherein the recess is recessed in an axis direction of the member from the first face and penetrates through in a side face direction of the member.

(9) The electrode according to (7) above,wherein the member has a through hole and/or a recess in the first face,wherein the through hole penetrates between the first face and a face other than the first face, andwherein the recess is recessed in an axis direction of the member from the first face and penetrates through in a side face direction of the member.

(10) An electrode kit comprising:the electrode according to any one of (1) to (6) above; anda holder connected to a power supply,wherein the other end of each of the conductors is electrically connected to the holder, and power is supplied to each of the conductors from the power supply.

(11) An electrode kit comprising:the electrode according to (7) above; anda holder connected to a power supply,wherein the other end of each of the conductors is electrically connected to the holder, and power is supplied to each of the conductors from the power supply.

(12) An electrode kit comprising:the electrode according to (8) above; anda holder connected to a power supply,wherein the other end of each of the conductors is electrically connected to the holder, and power is supplied to each of the conductors from the power supply.

(13) An electrode kit comprising:the electrode according to (9) above; anda holder connected to a power supply,wherein the other end of each of the conductors is electrically connected to the holder, and power is supplied to each of the conductors from the power supply.

Advantageous Effect

The electrode disclosed in the present application can be easily arranged at a predetermined position when electroporation is performed on cells.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of an electrode and an electrode kit will be described below in detail with reference to the drawings. Note that, in the present specification, members having similar functions are labeled with the same or similar references. Further, for the members labeled with the same or similar references, duplicated description may be omitted.

Further, the position, the size, the range, or the like of each configuration illustrated in the drawings do not always represent the actual position, the actual size, the actual range, or the like for easier understanding. Thus, the disclosure in the present application is not necessarily limited to the position, the size, the range, like disclosed in the drawings.

First Embodiment of Electrode

Electrodes1A to1C according to a first embodiment will be described with reference toFIG.1toFIG.4.FIG.1Ais a diagram schematically illustrating an example of the external appearance of the electrode1A according to the first embodiment.FIG.1Bis a diagram of a first face31of the electrode1A when viewed from front.FIG.1Cis a sectional view taken along the arrow X-X′ ofFIG.1B.FIG.2Ais a diagram of the first face31of the electrode1B when viewed from front.FIG.2Bis a sectional view taken along the arrow X-X′ ofFIG.2A.FIG.3Ais a diagram of the first face31of the electrode1C when viewed from front.FIG.3Bis a sectional view taken along the arrow Y-Y′ ofFIG.3A.FIG.4is a diagram illustrating protruding parts34provided to the first face31of a member3as an example.

The electrode1A according to the first embodiment is used when electroporation is performed on cells. The electrode1at least has at least two or more conductors2(in the following description, two or more conductors may be simply referred to as “conductors”) and a member3.

The conductors2are held in the member3described later. Further, the conductors2are electrically connected to an external power supply and used to perform electroporation on cells by using electric pulses supplied from the power supply. The conductor2may be any conductor as long as it can conduct electric pulses supplied from the power supply, and the shape or the material of the conductor2is not particularly limited. The shape of the conductor2may be, for example, a plate shape, a bar shape, or the like. In the example illustrated inFIG.1, the conductor2has a plate shape. Further, the material of the conductor2may be, for example, gold, platinum, stainless, titanium, chromium, tungsten, carbon, or the like. Note that these two or more conductors2may be of the same shape and material or may be of different shapes or materials as long as they can perform electroporation on cells.

The member3holds the conductors2and exposes at least one ends of the conductors2from the surface of the member3so that the conductors2can perform electroporation on cells. Further, the other ends of the conductors2held by the member3may be in any form as long as they can be electrically connected to the external power supply and may or may not be exposed from the surface of the member3. Note that, in the present specification, the face where one ends of the conductors2that perform electroporation on adherent cells of the member3(hereafter, which may be referred to as “end(s)21”) is exposed is defined as the first face31, and the face opposite to the first face31is defined as a second face32.

In the example illustrated inFIG.1, the other ends of the conductor2held by the member3(hereafter, which may be referred to as “end(s)22”, however, references “21” and “22” may be omitted in some drawings to avoid complicating the drawings) is exposed in the second face32of the member3. Alternatively, although not illustrated, the ends22of the conductors2may not be exposed in the second face32. In such a case, to enable electrical connection to the external power supply, the member3may have an insertion hole passing through from the second face32to the ends of the conductors2. Furthermore, the conductor2held by the member3may have an L-shape.FIG.2illustrates an electrode1B that holds the L-shaped conductors2in the member3. Since the member3of the electrode1B holds the L-shaped conductors2, when the ends21of the conductors2are exposed in the first face31, the ends22of the conductors2are exposed in a side face33of the member3in the example illustrated inFIG.2. Therefore, in the electrode1B, the ends22of the conductors2exposed in the side face33of the member3are electrically connected to the external power supply.

Although the member3has a cylindrical shape in the example illustrated inFIG.1, the member3may have any shape as long as it can hold the conductors2, and the shape is not particularly limited. The shape of the member3may be any shape other than a cylindrical shape, for example, may be a polygonal prism shape. Further, the material of the member3is not particularly limited as long as it is an insulator, for example, may be a resin or the like. The resin may be, for example, silicone, polypropylene, polycarbonate, thermosetting urethane, epoxy, acrylic, or the like.

Further, the conductors2held by the member3are required to have a positive polarity and a negative polarity when electroporation is performed. Therefore, while the member3holds at least two conductors2, this does not limit that the member3holds three or more conductors2. The number of conductors2held by the member3can be, for example, two, three, four, or the like. Note that, in the conventional electrode with legs, the three conductors81are coated with the insulator82, respectively, as illustrated inFIG.8. Thus, when it is understood that the insulator82corresponds to a member to hold the conductors81, the insulator82is not a member to hold at least two or more conductors81. It is therefore apparent that the configuration of the electrode1disclosed in the present application differs from the configuration of the electrode with legs of the conventional art.

The length by which the end21of each conductor2is exposed from the first face31(in other words, the length of the conductor2protruding from the first face31) is not particularly as limited long as electroporation can be performed on cells. While electroporation can be performed as long as the first face31and the end faces of the ends21of the conductors2are on the same level, it is preferable that the ends21of the conductors2protrude from the first face31. When electroporation is performed, the efficiency thereof varies in accordance with the amount of electroporation buffer (hereafter, which may be referred to as “buffer”), the surface area of the conductor2exposed from the first face31, or the like. Therefore, to achieve desired efficiency of electroporation in accordance with the situation where the electrode1A according to the first embodiment is used, the surface area of the conductor2exposed from the first face31can be designed as appropriate.

The member3has at least one or more protruding parts34. Each protruding part34is provided to the first face31of the member3and protrudes in the axis L direction of the member3. In the present specification, the axis (L) direction of the member3means the direction of the center axis of a prism when the member3has a prism shape such as a circular prism shape or a polygonal prism shape, for example. Note that, when the shape of the member3is not a prism, the direction substantially perpendicular to the first face31may be the axis direction. Further, when two or more conductors2are held by the member3so as to be substantially parallel to each other, it can also be said that the axis direction is a direction parallel to the conductors2.

Further, the length by which the protruding part34protrudes in the axis L direction from the first face31is longer than the length by which the end21of each conductor2is exposed from the first face31. Thus, when the electrode1A according to the first embodiment is used to perform electroporation on adherent cells adhered to a substrate or the like, since the top of the protruding part34is located on the substrate side from the ends21of the conductors2exposed in the first face31, the ends21of the conductors2are not in contact with the adherent cells. Therefore, this prevents adherent cells from being significantly damaged due to supply of electric pulses. Note that the electrode1A disclosed in the present application can be suitably used for electroporation on adherent cells in an adhered state and can also be used for electroporation on other cells such as floating cells. In such a case, the length by which the protruding part34protrudes in the axis L direction from the first face31can be adjusted as appropriate.

Further, in the electrode1A according to the first embodiment, because the member3has the protruding parts34, the protruding parts34come into contact with a substrate or the like and keep the attitude of the electrode1A when the electrode1A is installed to the substrate or the like. Therefore, this makes it easier to maintain the conductors2exposed in the first face31of the member3at a predetermined position. In the conventional electrode with legs, it is not possible to provide legs to a part other than the tip of the electrode because of the structure thereof. In contrast, in the electrode1A, since the member3holds the conductors2, it is possible to provide the protruding parts34to the first face31. In the example illustrated inFIG.1, the protruding parts34are provided along the outer circumference of the first face31of the member3. Because the protruding parts34are provided along the outer circumference, when the electrode1A is installed to a substrate or the like, the contact portion between the protruding parts34and the substrate or the like is increased, and this makes it easier to maintain the conductors2stably in the place where the electrode1A is installed.

The number of protruding parts34, the shape of the protruding part34, and the place to arrange the protruding parts34are not particularly limited as long as the conductors2are maintained stably at places where the electrode1A is installed after installation of the electrode1A. Since the protruding parts34protrude from the first face31, when the electrode1A is put into the buffer, air may remain in the space surrounded by the first face31and the protruding part34. If air remains, this may cause a problem with electrical conduction between the conductors2facing each other. It is therefore preferable to design the protruding parts34so that the air around the first face31A of the member3does not remain when the electrode1A is put into the buffer. In the example illustrated inFIG.1, two protruding parts34are provided spaced apart from each other to form clearances35so that the air around the first face31of the member3does not remain. Note that, as described later, the protruding part34may be provided to the entire outer circumference of the first face31, and a through hole to allow air remaining in the member3to escape may be provided.

Further, a slope part36may be provided to the first face31to facilitate air to move from the first face31to outside.FIG.3illustrates an example of the electrode1C in which the slope part36is provided to the first face31interposed between the conductors2facing each other. The slope part36is not particularly limited as long as it has a shape that facilitates air of the portion interposed between the conductors2facing each other to move in the outer circumferential direction of the member3along the slope part36due to floating force when the electrode1C is put into the buffer. In the example illustrated inFIG.3, the direction that is substantially orthogonal to the axis L direction and substantially orthogonal to the conductors2facing each other is defined as D1, and the direction opposite to the direction in which the protruding part34protrudes from the first face31is defined as D2. In the example illustrated inFIG.3B, the slope part36is inclined in the D2direction from substantially the center portion of the first face31interposed between the conductors2facing each other as any slope face36ais closer to the outer circumference of the member3in the D1direction. Therefore, even when the electrode1C is put into the buffer, air moves in the outer circumferential direction of the member3along the slope part36of the first face31. Note that it is preferable, but is not limited, that the clearances35be formed in the inclination direction of the slope part36.

Note that, in the example illustrated inFIG.3B, the slope part36is formed from substantially the center portion of the first face31interposed between the conductors2facing each other. Alternatively, the slope part36may be formed on the outer circumferential side from the portion of the first face31interposed between the conductors2facing each other (may be formed in a portion close to the clearances35in the example illustrated inFIG.3A). When the slope part36is formed in the portion close to the clearances35, it is possible to easily adjust the surface area of the conductors2exposed from the first face31in the same manner as in the examples illustrated inFIG.1andFIG.2.

Further, in terms of easier adjustment of the surface area of the conductors2exposed from the first face31, the slope part36may be formed to a portion spaced apart from the conductors2in the first face31interposed between the conductors2facing each other. While the slope part36is formed in contact with the conductors2in the example illustrated inFIG.3B, it is possible to easily adjust the surface area of the conductors2exposed from the first face31by forming the slope part36to the portion spaced apart from the conductors2(in the example illustrated inFIG.3A, in the direction of the dotted line illustrated by Y-Y′ from the conductors2).

The protruding parts34may be arranged between a plurality of conductors2. However, since electric pulses are supplied to the conductors2, it is preferable not to arrange the protruding parts34between the conductors2exposed in the first face31so as to less affect the electric field. Further, it is more preferable to arrange the protruding parts34on the outer circumferential side from the conductors2exposed in the first face31. Because the protruding parts34are arranged outside the conductors2, when the electrode1A is installed to a substrate or the like, a contact portion between the protruding parts34and the substrate or the like is increased, and the conductors2can be maintained stably in the place where the electrode1A is installed. Further, when the protruding parts34are arranged outside the conductors2, it is possible to increase the distance between any points of the protruding parts34. Thus, when the electrode1A is installed to the substrate or the like, the conductors2can be maintained stably in the place where the electrode1A is installed.FIG.4illustrates, not as a limitation, an example in which different protruding parts34from those in the example illustrated inFIG.1are provided.FIG.4illustrates the first face31of the member3when viewed from front.FIG.4Aillustrates an example in which the protruding parts34of the example illustrated inFIG.1Bare arranged with rotation by 90 degrees thereof.FIG.4BtoFIG.4Dillustrate examples in which the number of protruding parts34is two, three, and four. Further, as with the example illustrated inFIG.4D, the protruding parts34may be arranged inside the outer circumference of the first face31. In the example illustrated inFIG.4, the protruding parts34are spaced apart from each other to form the clearances35. Therefore, when the electrode1is put into the buffer, the air around the first face31can move along the first face31to outside of the member3through any of the clearances.

Note that, as described above, in terms of electrical conduction between the conductors2facing each other, it is preferable that no air remain between the conductors2facing each other. Therefore, as illustrated inFIG.1B, when, in the outer circumferential portion of the first face31, a portion interposed between virtual lines IL extending from the conductors2facing each other is defined as an outer circumferential virtual region IR, it is preferable that the clearances35, which are provided by the protruding parts34being spaced apart from each other, and the outer circumferential virtual region IR at least partially overlap each other. Because at least a part of the clearances35overlaps the outer circumferential virtual region IR, this facilitates the air between the conductors2facing each other to escape from the clearances35between the protruding parts34. Note that, although the whole of each clearance35is included in the outer circumferential virtual region IR in the example illustrated inFIG.1B, the clearance35may be made larger so as to include the whole outer circumferential virtual region IR as illustrated inFIG.4B. Further, as illustrated inFIG.4C, one of the clearances may overlap the outer circumferential virtual region IR.

The electrodes1A to1C according to the first embodiment achieve the following advantageous effects.

(1) Since the member3of the electrodes1A to1C has the protruding parts34on the first face31, when each of the electrodes1A to1C is installed to a substrate or the like, the conductors2can be maintained stably in the place where each of the electrodes1A to1C is installed. Further, the conventional electrode is fabricated by first coating the conductor81with the insulator82and then holding the conductor81coated with the insulator82in a holding portion. Thus, as illustrated inFIG.8, the distance from the holding portion to the tip of the conductor81is relatively long. In contrast, in the electrodes1A to1C, since the conductors2except for the portion exposed from the first face31are held by the member3, the centroid of the electrode in use can be lowered compared to the conventional electrode. Therefore, with the use of the electrodes1A to1C, electroporation can be stably performed.

(2) The length by which the protruding part34protrudes in the axis L direction from the first face31is longer than the length by which the end21of the conductor2is exposed from the first face31. Therefore, when each of the electrodes1A to1C is used for electroporation on adherent cells, the electroporation can be performed without the conductors2being in contact with the adherent cells.

(3) When the slope part36is provided to the first face31interposed between the conductors2facing each other, air moves to the outer circumferential side of the member3along the slope part36even when the electrode is put into the buffer. Therefore, a likelihood of air remaining between the conductors2is reduced.

(4) Since each of the electrodes1A to1C can be handled as a separate member from a power supply, the electrodes1A to1C can also be used as a disposable electrode.

Second Embodiment of Electrode

Electrodes1D to1F according to the second embodiment will be described with reference toFIG.5.FIG.5represents schematic diagrams illustrating examples of the electrodes1D to1F in which the member3has recesses37or a through hole38.FIG.5Ais a diagram of the first face31of the electrode1D when viewed from front.FIG.5Bis a sectional view taken along the arrow X-X′ ofFIG.5A.FIG.5Cis a diagram of the first face31of the electrode1E when viewed from front.FIG.5Dis a sectional view taken along the arrow X-X′ ofFIG.5C.FIG.5Eis a diagram of the first face31of the electrode1F when viewed from front.FIG.5Fis a sectional view taken along the arrow X-X′ ofFIG.5E.

The electrodes1D to1F according to the second embodiment differ from those of the first embodiment in that the member3has the through hole38and/or the recesses37in the first face31. Therefore, for the electrodes1D to1F according to the second embodiment, features different from those of the first embodiment will be mainly described, and duplicated description for the features that have already been described in the first embodiment will be omitted. Thus, it is apparent that, even when not explicitly described in the second embodiment, the features that have already been described in the first embodiment can be employed.

The recess37is provided in the first face31, is recessed in the axis L direction of the member, and penetrates through in the side face33direction of the member3. Further, the through hole38penetrates through the first face31and a face other than the first face31. Because the member3has the recesses37and/or the through hole38, the space surrounded by the first face31and the protruding parts34is connected to outside of the member3via the recesses37and/or the through hole38. Therefore, when each of the electrodes1D to1F is put into the buffer, air of the space surrounded by the first face31and the protruding parts34can be more reliably discharged through the recesses37and/or the through hole38.

The number of recesses37and through holes38and the arrangement of the recesses37and the through holes38provided in the first face31are not particularly limited as long as they can connect the space surrounded by the first face31and the protruding parts34to outside, and the member3may have any one of or both of the recess37and the through hole38.

In the example of the electrodes1D and1E illustrated inFIG.5AtoFIG.5D, the recess37recessed in the axis L direction from the first face31and penetrating through in the side face33direction is provided between the conductors2. Further, in the example of electrode1E illustrated inFIG.5CandFIG.5D, three conductors2are held by the member3, and two recesses37are provided in the member3. Further, in the example of the electrode1F illustrated inFIG.5EandFIG.5F, the through hole38penetrating through the first face31and the second face32is provided in the member3. Because the member3has the through hole38as with the electrode1F, the member3may have a single protruding part34not disconnected on the outer circumference of the first face31. Although not illustrated, the through hole38may penetrate from the first face31to the side face33. Note that, although provided between the conductors2in the examples of the electrodes1D to1F illustrated inFIG.5, the recess37or the through hole38may be provided in a place other than the above, for example, provided between each conductor2and the outer circumference of the member3.

The electrodes1D to1F according to the second embodiment synergistically achieve the following advantageous effects in addition to the advantageous effects achieved by the electrodes1A to1C according to the first embodiment.

(1) The member3has the recess(s)37and/or the through hole38, and this enables more reliable discharge of air of the space surrounded by the first face31and the protruding parts34. Therefore, electroporation can be performed without any contact of the conductors2exposed in the first face31with air.

(2) In the case of the electrodes1A to1C according to the first embodiment, the length by which the protruding part34protrudes in the axis L direction from the first face31is required to be designed in accordance with use. For example, when electroporation is performed on adherent cells, the length by which the protruding part34protrudes in the axis L direction from the first face31is relatively shorter. Accordingly, the size of each clearance35, which is formed by the protruding parts34being spaced apart from each other, depends on the width of the protruding parts34. In contrast, in the electrodes1D to1F according to the second embodiment, the size of each recess37and/or each through hole38can be decided regardless of the length by which the protruding part34protrudes, and this improves flexibility of design.

Embodiment of Electrode Kit

An electrode kit has at least any one of the electrodes1A to1F and a holder. The electrodes1A to1F of the electrode kit have already been described in the above embodiments. Thus, duplicated description will be omitted for the electrodes1A to1F.

The holder electrically connects an external power supply to the conductors2held by the member3of the electrodes1A to1F and is used to supply power from the external power supply to the conductors2. The holder is not particularly limited as long as it can electrically connect the external power supply and the conductors2of the member3to each other. For example, in the example of the electrode1A illustrated inFIG.1, since the conductors2protrude from the second face32and are exposed, a holder to be fitted to the protruding conductors2may be used. Further, in the example of the electrode1B illustrated inFIG.2, since the conductors2are exposed in the side face33of the member3, a holder contacted with the conductors2exposed in the side face33of the member3to form electrical connection to the conductors2may be used. Furthermore, when the conductors2electrically connected to the external power supply are not exposed from the member3and the member3has an insertion hole connected to the conductors2, the holder can have an insertion part inserted into the insertion hole so as to be electrically connected to the conductors2.

The electrode kit according to the embodiment is characterized in that the electrode kit includes the electrode1according to the above embodiments. Therefore, the same advantageous effects as those of the electrodes1A to1F according to the above embodiment are achieved.

Note that the present invention is not limited to the embodiment described above. Within the scope of the present invention, any combination of respective embodiments described above, modification of any component of each embodiment, or omission of any component of each embodiment is possible.

EXAMPLES

Electroporation was performed on adherent cells by using the electrode1. The materials, devices, and procedures used will be described below. Further,FIG.6illustrates the electrode1used.FIG.6Ais a diagram of the first face31when viewed from front.FIG.6Bis a sectional view taken along the arrow X-X′ ofFIG.6A. As the electrode1, an electrode in which three plate-like conductors2were held in the member3was used. [Material and Device]African green monkey's kidney cells COS-1adhered to a 24-well platePlasmid DNA incorporating green fluorescent protein (GFP) geneOpti-MEM I (Invitrogen) (buffer)Cell culture medium for post-culture (DMEM medium (Sigma)+10% FBS (Thermo) penicillin-streptomycin mixed solution (Nacalai Tesque) diluted 100-fold addition)Electroporator (CUY21EDIT II (BEX CO., LTD.)Electrode 1 (Each size of a to k illustrated inFIG.6is listed in Table 1)Fluorescent microscope (Nikon DIAPHOTO300, Nikon HB-10103AF, ultra-high pressure mercury lamp power supply device)

Procedure

1. Plasmid DNA was added to the buffer to give plasmid DNA concentration of 5 μg/μL.

2. The wells to which cells were adhered were washed by the buffer.

3. The buffer of 250 μL including the plasmid DNA prepared in 1. was added to the wells.

4. The electrode1was arranged in the well so that the cells were not detached therefrom.

5. Electroporation was performed. In the electroporation, the electrode1was connected to the electroporator such that the center conductor2was positive, and two conductors on both sides were negative, and electric pulses were supplied to the cells in a damped wave (Decay (V)) mode. The poration pulse (Pp) and the driving pulse (Pd) in the damped wave mode were set as follows.Pd setting valueVoltage: 250VPulse duration (Pon): 10 msPulse interval (Poff): 50 msPd setting valueVoltage: 30VPulse duration (Pon): 50 msPulse interval (Poff): 50 msNumber of pulses: 5Pattern: +/−Capacitance: 940 μF

6. The electrode1was taken out of the well, and the well plate was incubated for 10 minutes in a CO2incubator for recovering the cells.

7. The buffer was removed from the well, and a pre-incubated cell culture medium for post-culture was gently added thereto.

8. The well plate was moved to the CO2incubator, and post-culture was started.

9. After 48 hours of the post-culture, the well plate was taken out of the CO2incubator, and the cells were observed by using the fluorescent microscope.

Comparative Example 1

Comparative example 1 is the same as Example 1 except that the electrode used in electroporation was the conventional electrode with legs (LF513-5, BEX CO., LTD.).

With respect to the electrode1used in Example 1, when the electrode1was arranged in the well, the conductors2was maintained at a predetermined position stably due to the protruding parts34of the member3. Further, since the tips of the protruding parts34protrude more than the ends21of the conductors2exposed in the first face31of the member3of the electrode1, the conductors2did not come into contact with cells. Therefore, in Example 1, with the use of the electrode1, the conductors2was maintained at a predetermined position, and the electroporation on adherent cells was stably performed. In contrast, in Comparative example 1, since the conventional electrode with legs was used, it was difficult to stably maintain the electrode with legs at a predetermined position.

After the electroporation was performed, the post-cultured adherent cells were observed by using the fluorescent microscope.FIG.7illustrates the result. It was indicated inFIG.7that, in both Example 1 and Comparative example 1, plasmid DNA was introduced to the adherent cells by electroporation, and GFP was expressed. It was therefore shown that the electrode1used in Example 1 can perform electroporation at efficiency to the same degree as the conventional electrode with legs. Thus, it was shown that the electrode1can maintain the position the conductors more stably than the conventional electrode with legs and can introduce genes to adherent cells to the same degree as the conventional electrode with legs, and therefore, the electrode1can perform electroporation in a simple manner.

INDUSTRIAL APPLICABILITY

The use of the electrode and the electrode kit disclosed in the present application makes it easier to arrange the electrode at a predetermined position when performing electroporation on cells. Therefore, the electrode and the electrode kit are useful for business entities that handle an electrode used for performing electroporation on cells.

LIST OF REFERENCES