Magnesium iontophoresis patch

Abstract

Provided is a magnesium iontophoresis patch 1 which has: a battery part 2 comprising a positive electrode 201, a negative electrode 202, and a separator 203; and an active ingredient 3 stored so as not to come into contact with the battery part 2. The positive electrode 201 contains a carbonized cellulose having a three-dimensional network structure, and the negative electrode 202 contains magnesium. The separator 203 contains no electrolyte, and when the magnesium iontophoresis patch 1 is used, the positive electrode 201, the negative electrode 202, and the separator 203 are impregnated with the active ingredient 3 acting as an electrolyte to start the battery reaction.

Description

Magnesium iontophoresis patch

[0001] The present disclosure relates to magnesium iontophoretic patches.

[0002] Liquid and cream-based cosmetics and pharmaceuticals are widely available. In recent years, magnesium has been attracting attention as an active ingredient in cosmetics and pharmaceuticals. Magnesium itself has antibacterial and antioxidant properties, and there are also reports that it can restore the skin's barrier function and promote the penetration of high-molecular-weight active ingredients such as hyaluronic acid.

[0003] To promote the penetration of magnesium ions, magnesium chloride is added to the active ingredient, and microneedles made of metal are known (Non-Patent Document 1).

[0004] "LABnPEOPLE," https: / / www.labnp.com / en

[0005] However, when magnesium chloride is added, it is difficult to add a sufficient amount of magnesium, and even with microneedles, magnesium needles are inserted directly into living tissue, so the treatment is not completely painless and involves some discomfort.

[0006] The present disclosure has been made in view of the above, and aims to provide a magnesium iontophoretic patch that promotes the introduction of magnesium ions.

[0007] In order to solve the above problems, the magnesium iontophoresis patch according to the present disclosure is a magnesium iontophoresis patch that is attached to biological tissue for use, and has a battery section including a positive electrode, a negative electrode, and a separator, and an active ingredient that is accommodated so as not to come into contact with the battery section, wherein the positive electrode contains carbonized cellulose with a three-dimensional network structure, the negative electrode contains magnesium, and the separator does not contain an electrolyte, and when the biological tissue-attached patch is used, the active ingredient that acts as an electrolyte is impregnated into the positive electrode, the negative electrode, and the separator to initiate a battery reaction.

[0008] According to the present disclosure, a magnesium iontophoretic patch that promotes the introduction of magnesium ions can be provided.

[0009] FIG. 1 is a diagram illustrating the principle by which magnesium ions promote the penetration of hyaluronic acid. FIG. 2 is a plan view showing the configuration of a magnesium iontophoretic patch of this embodiment. FIG. 3 is a diagram showing the state in which the partition of the magnesium iontophoretic patch of FIG. 2 has been broken and the active ingredient has been brought into contact with the battery unit. FIG. 4 is a diagram showing the state in which the battery unit of FIG. 3 is attached to biological tissue for use. FIG. 5 is a schematic diagram showing an example of the configuration of the battery unit. FIG. 6 is a flowchart showing a method for producing bacterially-produced carbonized cellulose. FIG. 7 is a flowchart showing the process of supporting a catalyst on bacterially-produced carbonized cellulose. FIG. 8 is a flowchart showing another method for producing a positive electrode. FIG. 9 is a flowchart showing a method for producing a negative electrode. FIG. 10 is an exploded perspective view of the battery unit of Example 1. FIG. 11 is a cross-sectional view of the battery unit of Example 1. FIG. 12 is a plan view showing the configuration of the magnesium iontophoretic patch of Example 1. FIG. 13 is a diagram showing the state in which the battery unit is placed on a test strip. FIG. 14 is a perspective view of a patch of Comparative Example 1. FIG. 15 is a cross-sectional view of a patch of Comparative Example 1. FIG. 16 is a diagram showing the measurement results of Example 1 and Comparative Example 1. Fig. 17 is an exploded perspective view of the battery unit of Example 2. Fig. 18 is a cross-sectional view of the battery unit of Example 2. Fig. 19 is an exploded perspective view of the battery unit of Example 3. Fig. 20 is a cross-sectional view of the battery unit of Example 3. Fig. 21 is an exploded perspective view of the battery unit of Examples 4 and 5. Fig. 22 is a cross-sectional view of the battery unit of Examples 4 and 5.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] (Configuration of Magnesium Iontophoretic Patch) The magnesium iontophoretic patch of this embodiment is a patch for infusing magnesium ions into biological tissues using electricity generated by a reaction similar to that of a general magnesium-air battery.

[0012] Figure 1 shows the principle of how magnesium ions promote the penetration of hyaluronic acid. Hyaluronic acid is an anionic polymer, and has a large volume due to electronic repulsion. By applying magnesium ions to this, the volume of hyaluronic acid can be reduced by tilting it towards an amphoteric state. This volume reduction promotes penetration into the skin.

[0013] FIG. 2 is a plan view showing the configuration of the magnesium iontophoretic patch of this embodiment. The magnesium iontophoretic patch 1 shown in FIG. 2 has a battery section 2 and an active ingredient 3. The battery section 2 and the active ingredient 3 are housed separately in a plastic pack 4. The battery section 2 does not contain an electrolyte, which is required in general batteries, and is stored in a state in which a battery reaction does not occur. The active ingredient 3 may be in any form, such as a liquid, cream, or gel, as long as it functions as an electrolyte for the battery section 2 when the magnesium iontophoretic patch 1 is used. For example, if the separator of the battery section 2 is impregnated with the active ingredient 3, the active ingredient 3 will function as an electrolyte and initiate a battery reaction.

[0014] The plastic pack 4 has a battery storage section 42 that houses the battery section 2 and an active ingredient storage section 43 that houses the active ingredient 3. The battery storage section 42 and the active ingredient storage section 43 are separated by a partition 41. Both ends 44, 45 of the plastic pack 4 are sealed by heat sealing. Various materials, such as vinyl, polystyrene, and acrylic, can be used as the material for the plastic pack 4. More specifically, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, high-density polyethylene, medium-density polyethylene, low-density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, homopolymer polyacetal, copolymer polyacetal, polymethyl methacrylate, polyester, PPS, polypropylene, cellophane, acetate, polycarbonate, nylon, and polyimide can be used.

[0015] The partition 41 is not particularly limited as long as it can separate and store the battery part 2 and the active ingredient 3. For example, it is preferable to separate the battery part storage part 42 and the active ingredient storage part 43 by heat sealing, adhesive, or a zipper. In particular, heat sealing is preferable from the viewpoint of complexity and cost during manufacturing.

[0016] In addition to the above-mentioned components, the magnesium iontophoretic patch 1 can include structural members such as an exterior film, a case, an adhesive, and a metal foil, as well as elements required for a general magnesium-air battery. These may be conventionally known components.

[0017] When using the magnesium iontophoresis patch 1, the active ingredient 3 is brought into contact with the battery portion 2. The active ingredient 3 functions similarly to an electrolyte, and a battery reaction is initiated in the battery portion 2. For example, as shown in FIG. 3 , the partition 41 is torn to form an opening 46, and the active ingredient 3 is brought into contact with the battery portion 2. A suitable method for breaking the partition 41 is to apply pressure with a finger to the active ingredient storage portion 43 in which the active ingredient 3 is stored, as this method is easy and inexpensive. If the pressure is insufficient to break the partition 41, folding the active ingredient storage portion 43 in half and pressing it increases the pressure, making it possible to break the partition 41. The method for breaking the partition 41 is not particularly limited, but examples include piercing the partition 41 with a sharp needle or toothpick, cutting the partition 41 with scissors, or tearing the partition 41 by hand.

[0018] After the battery reaction has started, the battery part 2 is removed from the battery part storage part 42 and attached to the biological tissue 100 for use, as shown in Fig. 4. The shapes of the magnesium iontophoresis patch 1 and the battery part 2 are not particularly limited. For example, they may be in the form of a patch, a face mask, an eye mask, a glove, a bandage, a bandage, or a compress.

[0019] (Configuration of Battery Unit) Next, the configuration of the battery unit 2 will be described.

[0020] FIG. 5 is a diagram showing a schematic example of the configuration of the battery module 2. As shown in FIG.

[0021] The battery unit 2 in Fig. 5 includes a positive electrode 201, a negative electrode 202 containing magnesium, and a separator 203 arranged to be in contact with the positive electrode 201 and the negative electrode 202. Unlike typical magnesium-air batteries, the battery unit 2 in Fig. 5 does not include current collectors in contact with the positive electrode 201 and the negative electrode 202, and further does not include an electrolyte. The battery unit 2 in Fig. 5 is used by attaching the positive electrode 201 and the negative electrode 202 to the biological tissue 100. In another configuration example of the battery unit 2, the positive electrode 201 and the negative electrode 202 may be in contact with each other.

[0022] Here, the electrode reactions at the positive electrode 201 and the negative electrode 202 will be described.

[0023] When the water contained in the active ingredient 3 comes into contact with oxygen in the air on the surface of the positive electrode 201, the reaction shown in the following formula (1) proceeds.

[0024] O2 + 2H2O + 4e - →4OH - ... (1)

[0025] Meanwhile, the reaction shown in the following formula (2) proceeds in the negative electrode 202 in contact with the active ingredient 3. Specifically, magnesium constituting the negative electrode 202 releases electrons and dissolves in the active ingredient 3 as magnesium ions.

[0026] Mg → Mg 2+ +2e - ... (2)

[0027] These reactions occur via the biological tissue 100. In the battery part 2 of Fig. 5, magnesium ions eluted from the negative electrode 202 are introduced into the biological tissue 100. In the battery part 2 of Fig. 5, electrons (current) flow through the separator 203 and the biological tissue 100 as the reactions of formulas (1) and (2) proceed.

[0028] The overall reaction of the battery is expressed by the following formula (3), which is a reaction to produce magnesium hydroxide.

[0029] 2Mg+O2+2H2O→2Mg(OH)2... (3)

[0030] The theoretical electromotive force is about 2.7 V. Figures 4 and 5 show the components of the battery section 2 as well as the compounds involved in the reaction.

[0031] Each component of the battery module 2 will now be described.

[0032] (I) Positive Electrode The positive electrode 201 can be a cathode used in a typical magnesium-air battery. For example, carbon, metal, oxide, nitride, carbide, sulfide, and phosphide can be used. Two or more of these materials may be mixed. The positive electrode 201 can be fabricated using a known process of molding carbon powder with a binder. Because fluorine-containing resins are typically used as binders, burning the positive electrode 201 during disposal, for example, generates hydrofluoric acid. Therefore, there is room for improvement, such as improving safety and reducing environmental impact. In this embodiment, bacterially produced carbonized cellulose or cellulose nanofiber carbon is used for the positive electrode 201, eliminating the use of fluorine-containing resins. The bacterially produced carbonized cellulose used for the positive electrode 201 has a three-dimensional network structure of carbonized bacterially produced cellulose. For example, the average pore diameter is preferably 0.1 to 50 μm, and more preferably 0.1 to 2 μm. The average pore diameter is determined by mercury intrusion porosimetry. The cellulose nanofiber carbon used in the positive electrode 201 has a three-dimensional network structure of carbonized cellulose nanofibers, and preferably has a fiber diameter of 5 to 500 nm, and more preferably 20 to 200 nm, for example.

[0033] The positive electrode 201 may support a catalyst. The catalyst may be a metal, oxide, nitride, carbide, sulfide, or phosphide. Two or more of these may be mixed. Examples of metals that can be used include iron, manganese, copper, nickel, silver, gold, platinum, cobalt, ruthenium, molybdenum, titanium, chromium, gallium, praseodymium, aluminum, silicon, and tin. Alloys containing two or more of these metals are also acceptable. Oxides made from one of the above metals or composite oxides made from two or more of these metals are preferred. Iron oxide (Fe2O3) is particularly suitable. Iron oxide is desirable because it exhibits particularly excellent catalytic performance and is not a rare metal. The metal oxide used as the catalyst is preferably an amorphous hydrate. For example, it may be a hydrate of one of the transition metal oxides described above. More specifically, it may be an iron(III) oxide-n hydrate. n is the number of moles of H2O per 1 mol of Fe2O3.

[0034] By attaching (adding) highly dispersed nano-sized particles of hydrated iron oxide (Fe2O3.nH2O) to the surface of the bacterially produced carbonized cellulose of the positive electrode 201, it is possible to exhibit excellent performance. The content of the catalyst contained in the positive electrode 201 is 0.1 to 70 wt %, preferably 1 to 30 wt %, based on the total weight of the positive electrode 201. By adding a transition metal oxide as a catalyst to the positive electrode 201, the performance of the battery module 2 is significantly improved.

[0035] The reaction shown in the above formula (1) proceeds on the surface of the positive electrode 201. Therefore, it is important to generate a large number of reaction sites inside the positive electrode 201, and it is desirable that the positive electrode 201 has a large specific surface area. For example, if the specific surface area of ​​the positive electrode 201 is 200 m 2 / g or more, and 2 / g or more is more preferable.

[0036] (II) Negative Electrode The negative electrode 202 is made of a negative electrode active material. The negative electrode active material may be any material that can be used as a negative electrode material for a magnesium-air battery, that is, any material that contains metallic magnesium or a magnesium-containing material. The negative electrode 202 may be made of, for example, metallic magnesium, a metallic magnesium sheet, or magnesium powder.

[0037] (III) Separator The separator 203 may be made of any material that is capable of containing the active ingredient 3 and is not electrically conductive. For example, Japanese paper, cotton, collagen, bacterial gel, and bacterial xerogel can be used. Bacterial xerogel is porous and therefore has high retention capacity for the active ingredient 3. Bacterial xerogel gels when it retains the active ingredient 3, and therefore has excellent adhesion to biological tissue.

[0038] (Regarding the Active Ingredients) Next, the active ingredients will be described.

[0039] In this embodiment, the "active ingredient" refers to a medicinal solution that is effective against a specific disease, a cosmetic solution intended to cleanse, beautify, and enhance the attractiveness of the human body, change the appearance, or keep the skin or hair healthy, water, or alcohol.

[0040] The active ingredient 3 may be any substance that allows magnesium ions and hydroxide ions to move between the positive electrode 201 and the negative electrode 202 via the biological tissue 100 or the separator 203 .

[0041] For example, the active ingredient may be an aqueous solution containing organic acids, inorganic acids, their derivatives, and their salts. For example, the active ingredient may be an anion species such as amino acid ions, chloride ions, citrate ions, lactate ions, succinate ions, phosphate ions, malate ions, pyrrolidone carboxylate ions, sulfocarbonate ions, sulfate ions, nitrate ions, carbonate ions, and perchlorate ions. For example, the amino acids may be glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, threonine, serine, proline, tryptophan, methionine, cysteine, aspartic acid, glutamic acid, asparagine, glutamine, lysine, arginine, histidine, hydroxyproline, cystine, and thyroxine.

[0042] Cationic species include potassium ions, sodium ions, lithium ions, calcium ions, magnesium ions, and zinc ions.

[0043] Specific examples of active ingredients include sodium salts of amino acids, sodium chloride, potassium chloride, magnesium chloride, sodium citrate, magnesium citrate, sodium lactate, magnesium lactate, calcium lactate, sodium succinate, magnesium succinate, sodium malate, magnesium malate, sodium pyrrolidone carboxylate, magnesium pyrrolidone carboxylate, zinc sulfocarbonate, potassium aluminum sulfate (alum), seawater, and hot spring water.

[0044] Furthermore, even for active ingredients that do not undergo migration of magnesium ions and hydroxide ions, the magnesium ions and hydroxide ions may be migrated by adding the above-mentioned amino acid sodium salts, sodium chloride, potassium chloride, magnesium chloride, sodium citrate, magnesium citrate, sodium lactate, magnesium lactate, calcium lactate, sodium succinate, magnesium succinate, sodium malate, magnesium malate, sodium pyrrolidone carboxylate, magnesium pyrrolidone carboxylate, zinc sulfonate, aluminum potassium sulfate (alum), seawater, and hot spring water. In this way, by separately adding the amino acid sodium salts, sodium chloride, potassium chloride, magnesium chloride, sodium citrate, magnesium citrate, sodium lactate, magnesium lactate, calcium lactate, sodium succinate, magnesium succinate, sodium malate, magnesium malate, sodium pyrrolidone carboxylate, magnesium pyrrolidone carboxylate, zinc sulfonate, aluminum potassium sulfate (alum), seawater, and hot spring water, the active ingredient can be used in almost all commonly available pharmaceuticals, quasi-drugs, cosmetics, and supplements.

[0045] For example, the following are examples of pharmaceuticals, quasi-drugs, cosmetics, and supplements:

[0046] Examples of substances that have anti-aging effects include uric acid, glutathione, meatonin, polyphenols, melanoidin, astaxanthin, kinetin, epigallocatechin gallate, coenzyme Q10, vitamins, superoxide dismutase, mannitol, quercetin, catechin and its derivatives, rutin and its derivatives, Moutan Pea extract, Aloe barbadensis leaf extract, Melissa extract, Monk fruit extract, dibutylhydroxytoluene, and butylhydroxyanisole.

[0047] Examples of substances with whitening effects include whitening agents and anti-inflammatory agents. Whitening agents have the effect of preventing the darkening of skin caused by sunburn and the development of age spots and freckles caused by pigmentation. Examples of whitening agents include arbutin, ellagic acid, linoleic acid, vitamin C and its derivatives, kojic acid, tranexamic acid, placenta extract, chamomile extract, licorice extract, star anise extract, Scutellaria root extract, seaweed extract, Sophora root extract, kaempferi extract, kanji extract, rice bran extract, wheat germ extract, Chinese radish extract, Japanese hawthorn extract, sunflower extract, white lily extract, peony extract, scutellaria extract, soybean extract, tea extract, molasses extract, white angelica tree extract, grape extract, hop extract, squid extract, mokka extract, and saxifrage extract. Anti-inflammatory agents have the effect of suppressing the inflammation of hot flashes and erythema caused by sunburn. Examples of anti-inflammatory agents include sulfur and derivatives thereof, glycyrrhizic acid and derivatives thereof, glycyrrhetinic acid and derivatives thereof, althaea extract, angelica tree extract, chamomile extract, goldenrod extract, watercress extract, comfrey extract, salvia extract, lithospermum root extract, perilla extract, shiso extract, shikaraba extract, and gentian extract.

[0048] Those having peeling and brightening effects include, for example, alpha-hydroxy acids, salicylic acid, sulfur, and urea.

[0049] Examples of substances having a slimming effect include substances that have the effect of promoting blood circulation, such as plant extracts such as ginger, capsicum tincture, and sophora root, carbon dioxide, vitamin E, and its derivatives.

[0050] Examples of substances having moisturizing effects include proteins such as elastin and keratin, and their derivatives, hydrolyzed forms, and salts thereof; amino acids such as glycine, serine, ascorbic acid, glutamic acid, arginine, and theanine, and their derivatives; sorbitol, erythritol, trehalose, inositol, glucose, sucrose and its derivatives, dextrin and its derivatives, sugars such as honey, D-panthenol and its derivatives, sodium lactate, sodium pyrrolidonecarboxylate, sodium hyaluronate, mucopolysaccharides, urea, phospholipids, ceramide, coptis japonica extract, calamus extract, rehmannia root extract, cnidium extract, mallow extract, horse chestnut extract, and quince extract.

[0051] Examples of agents having a hair repair effect include isopropylmethylphenol, ginkgo biloba extract, L-menthol, carpronium chloride, diphenhydramine hydrochloride, Polygonum multiflorum (Polygonum multiflorum), dipotassium glycyrrhizinate, salicylic acid, dialkylmonoamine derivatives, ginger, cepharanthine, Cinnamon, Swertia japonica, Panax ginseng, Korean ginseng, capsicum tincture, Angelica acutiloba, trehalose, nicotinic acid / nicotinamide, vitamin E (tocopherol), hinokitiol, placenta extract, and pentadecanoic acid glyceride.

[0052] Examples of substances having a skin conditioning effect include substances intended to improve rough skin, such as improving barrier function or wound healing, etc. Examples of substances having a skin conditioning effect include ceramides, cholesterols, amine derivatives, caffeines, cockscomb extract, seashell extract, royal jelly, silk protein and its degradation products and derivatives thereof, lactoferrin and its degradation products, chondroitin sulfate, mucopolysaccharides such as hyaluronic acid and their salts, collagen, yeast extract, lactic acid bacteria extract, bifidobacterium extract, fermentation metabolism extract, ginkgo extract, barley extract, Swertia japonica extract, ginseng extract, arnica extract, turmeric extract, eucalyptus extract, cattail extract, soapwort extract, rosemary extract, glycolic extract, citric acid, lactic acid, malic acid, tartaric acid, and succinic acid.

[0053] Examples of soothing oils include lavender, rosemary, sandalwood, orris, bitter orange, cypress, and orange oil.

[0054] These drugs may be used alone or in combination of two or more.

[0055] Examples of cosmetics include lotions, emulsions, serums, creams, cream packs, massage creams, cleansing creams, cleansing gels, facial cleansers, sunscreens, styling gels, shampoos, body shampoos, hair setting gels, fragrances, and hair dyes. These cosmetics can provide anti-aging, whitening, peeling / brightening, slimming, moisturizing, hair repair, hair growth, skin conditioning, relaxation, and UV protection effects.

[0056] These cosmetics may be used alone or in combination of two or more.

[0057] (Method for Producing Positive Electrode) Next, a method for producing the positive electrode will be described.

[0058] First, a method for producing the bacterially produced carbonized cellulose that constitutes the positive electrode 201 will be described.

[0059] FIG. 6 is a flow chart showing a method for producing bacterially produced carbonized cellulose.

[0060] In the gel production process of step S101, specific bacteria are allowed to produce a gel in which cellulose nanofibers are dispersed. In the freezing process of step S102, the gel produced by the bacteria is frozen to form a frozen mass. In the drying process of step S103, the frozen mass is dried in a vacuum. Through these processes, a bacterially produced xerogel is obtained. In the carbonization process of step S104, the bacterially produced xerogel is heated and carbonized in an atmosphere of a gas that does not burn cellulose. This yields bacterially produced carbonized cellulose.

[0061] The term "gel" refers to a substance in which the dispersion medium loses fluidity and becomes solid due to the three-dimensional network structure of the nanostructure, which is the dispersoid. 2 ~10 6 The dispersion medium for the gel may be an aqueous system such as water (HO). Alternatively, the dispersion medium for the gel may be an organic system such as carboxylic acid, methanol (CHOH), ethanol (CHOH), propanol (CHOH), n-butanol, isobutanol, n-butylamine, dodecane, unsaturated fatty acid, ethylene glycol, heptane, hexadecane, isoamyl alcohol, octanol, isopropanol, acetone, or glycerin. Two or more of these may be mixed.

[0062] The gel produced by bacteria has a basic structure of nanofibers on the order of nm (fibrous material with a diameter of 1 nm to 1 μm and a length 100 times or more the diameter). The positive electrode 201 produced using this gel has a high specific surface area. Since it is desirable for the positive electrode 201 of the magnesium iontophoresis patch 1 to have a high specific surface area, it is preferable to use a gel produced by bacteria. Specifically, by using a gel produced by bacteria, it is possible to obtain a positive electrode 201 with a specific surface area of ​​300 m 2 / g or more.

[0063] The bacterial-produced gel has a structure in which fibers are entangled in coils and meshes, and furthermore, the nanofibers formed by bacterial growth have a branched structure. Therefore, the positive electrode 201 made from the bacterial-produced gel achieves excellent stretchability, with a strain of 50% or more at the elastic limit. Therefore, the positive electrode 201 made using the bacterial-produced gel can enhance adhesion to biological tissue.

[0064] Examples of bacteria include known bacteria, such as Acetobacter xylinum subsp. sucrofermenta, Acetobacter xylinum ATCC 23768, Acetobacter xylinum ATCC 23769, Acetobacter pasteurianus ATCC 10245, Acetobacter xylinum ATCC 14851, Acetobacter xylinum ATCC 11142, and Acetobacter xylinum ATCC 10821. Alternatively, the bacteria may be produced by culturing various mutant strains created by mutating the above bacteria by known methods using NTG (nitrosoguanidine) or the like.

[0065] In the freezing process, for example, the bacterial-produced gel is placed in an appropriate container such as a test tube, and the surrounding area of ​​the test tube is cooled in a coolant such as liquid nitrogen to freeze the bacterial-produced gel. The method for freezing the bacterial-produced gel is not particularly limited as long as the gel's dispersant can be cooled below its freezing point, and cooling in a freezer or the like is also acceptable. By freezing the bacterial-produced gel, the dispersant loses its fluidity, the cellulose dispersoid is fixed, and a three-dimensional network structure is constructed. If the cellulose dispersoid is not fixed by freezing, the dispersoid will aggregate as the dispersant evaporates in the subsequent drying process. As a result, a sufficiently high specific surface area cannot be obtained, making it difficult to fabricate a high-performance positive electrode 201.

[0066] The drying process is a process in which the frozen body obtained in the freezing process is dried to extract cellulose, a dispersoid that maintains or establishes a three-dimensional network structure, from the dispersion medium. In the drying process, the frozen body is dried in a vacuum, and the frozen dispersion medium is sublimated from its solid state. The drying process is carried out, for example, by placing the obtained frozen body in an appropriate container such as a flask and evacuating the container. By placing the frozen body in a vacuum atmosphere, the sublimation point of the dispersion medium is lowered, making it possible to sublimate substances that do not sublimate at normal pressure. The degree of vacuum in the drying process varies depending on the dispersion medium used, but is not particularly limited as long as it is a degree of vacuum that allows the dispersion medium to sublimate. For example, when water is used as the dispersion medium, a vacuum of 0.06 MPa or less is required, but drying takes time because heat is lost as latent heat of sublimation. For this reason, the degree of vacuum is set to 1.0 x 10 -6 ~1.0 x 10 -2 Pa is preferable. Furthermore, heat may be applied using a heater or the like during drying. When drying is performed in the atmosphere, the dispersion medium changes from solid to liquid and then from liquid to gas. When the dispersion medium becomes liquid, the dispersoid becomes fluid again in the dispersion medium, and the three-dimensional network structure of the cellulose collapses. For this reason, it is difficult to produce stretchable bacterially produced carbonized cellulose by drying in an atmospheric pressure environment.

[0067] Because cellulose, a component of the bacterially produced gel, is not electrically conductive, the carbonization process, which imparts electrical conductivity by heat-treating the cellulose in an inert gas atmosphere to carbonize it, is important. Bacterially produced carbonized cellulose has a three-dimensional network structure that is electrically conductive. Bacterially produced carbonized cellulose has high electrical conductivity, corrosion resistance, high elasticity, and a large specific surface area, making it suitable for use as the positive electrode 201 of the magnesium iontophoretic patch 1.

[0068] The carbonization step may involve carbonizing the bacterially produced xerogel by baking it in an inert gas atmosphere at 500 to 2000 degrees Celsius, more preferably at 900 to 1800 degrees Celsius. Examples of gases that do not burn cellulose include inert gases such as nitrogen gas and argon gas. The gas used may be a reducing gas such as hydrogen gas or carbon monoxide gas, or may be carbon dioxide gas. Carbon dioxide gas or carbon monoxide gas is more preferred as it has an activation effect on carbon materials and is expected to achieve high activation.

[0069] Next, the process of supporting a catalyst on bacterially produced carbonized cellulose will be described.

[0070] FIG. 7 is a flow chart showing the process of supporting a catalyst on bacterially produced carbonized cellulose.

[0071] In the impregnation step S201, the bacterially produced carbonized cellulose obtained by the above-mentioned production method is impregnated with an aqueous solution of a metal salt that serves as a catalyst precursor. In the heating step S202, the bacterially produced carbonized cellulose containing the metal salt is heat-treated.

[0072] The metal salt is preferably at least one metal selected from iron, manganese, copper, nickel, silver, gold, platinum, cobalt, ruthenium, molybdenum, titanium, chromium, gallium, praseodymium, aluminum, silicon, and tin. Iron is preferred because it has a low environmental impact and high electrode performance.

[0073] Conventional methods can be used to support transition metal oxides on bacterially produced carbonized cellulose. Examples include a method in which bacterially produced carbonized cellulose is impregnated with an aqueous solution of transition metal chloride or transition metal nitrate, evaporated to dryness, and then hydrothermal synthesis in water under high temperature and pressure; a precipitation method in which bacterially produced carbonized cellulose is impregnated with an aqueous solution of transition metal chloride or transition metal nitrate and then an aqueous alkali solution is added dropwise; and a sol-gel method in which bacterially produced carbonized cellulose is impregnated with a transition metal alkoxide solution and then hydrolyzed. The conditions for each of these liquid-phase methods are well known, and these known conditions can be applied. These liquid-phase methods are preferred because they allow transition metal oxides to be supported in a highly dispersed state.

[0074] In many cases, metal oxides supported by the liquid-phase method are amorphous because they are not yet crystallized. A crystalline metal oxide can be obtained by heat-treating an amorphous precursor at a high temperature of about 500°C in an inert atmosphere. Such crystalline metal oxides also exhibit high performance when used as a positive electrode catalyst.

[0075] On the other hand, when the amorphous precursor is dried at a relatively low temperature of about 100 to 200 degrees Celsius, the resulting precursor powder is in a hydrate state while maintaining the amorphous state. x O y nH2O (where Me represents the metal, x and y represent the number of metals and oxygen atoms contained in the metal oxide molecule, respectively, and n is the number of moles of H2O per mole of metal oxide). The metal oxide hydrate obtained by such low-temperature drying can be used as a catalyst.

[0076] Amorphous metal oxides (hydrates) are hardly sintered, so they have a large surface area and very small particle diameters of about 30 nm, making them suitable as catalysts, and their use can result in excellent battery performance.

[0077] As mentioned above, crystalline metal oxides exhibit high activity, but metal oxides crystallized by heat treatment at high temperatures as described above may have a significantly reduced surface area. For example, particle aggregation may result in a particle diameter of approximately 100 nm. Note that this particle diameter (average particle diameter) is the average value calculated by measuring the diameter of particles per 10 μm square (10 μm × 10 μm) under magnification observation using a scanning electron microscope (SEM) or the like.

[0078] Furthermore, catalysts based on metal oxides, especially those heat-treated at high temperatures, tend to aggregate, making it difficult to achieve high dispersion on the surface of bacterially produced carbonized cellulose. To achieve sufficient catalytic activity, a large amount of metal oxide may need to be added to the positive electrode, making the production of catalysts by high-temperature heat treatment cost-inefficient. To solve this problem, the amorphous precursor can be dried at a relatively low temperature, around 100 to 200 degrees Celsius, as described above.

[0079] The catalyst-unsupported, bacterially produced carbonized cellulose or catalyst-supported, bacterially produced carbonized cellulose obtained by the above-mentioned manufacturing method can be processed into a plate or sheet, and the plate or sheet of bacterially produced carbonized cellulose can be cut into the desired rectangle (e.g., 30 mm x 20 mm) using a punching blade, laser cutter, or the like to form the positive electrode 201.

[0080] Next, another method for producing the positive electrode will be described.

[0081] The bacterially produced carbonized cellulose obtained by the above-mentioned manufacturing method is brittle and can be difficult to process into the desired shape. However, by using the following alternative manufacturing method, it becomes easier to process the bacterially produced carbonized cellulose into a sheet.

[0082] FIG. 8 is a flowchart showing another method for manufacturing the positive electrode 201.

[0083] Steps S301 to S304 are the same as the method for producing bacterially produced carbonized cellulose described in Fig. 6. After step S304, a step of supporting a catalyst on the bacterially produced carbonized cellulose described in Fig. 7 may be carried out.

[0084] In the pulverization step of step S305, the bacterial-produced carbonized cellulose obtained in steps S301 to S304 is pulverized. In the pulverization step of step S306, the bacterial-produced gel obtained in step S301 is pulverized. In the mixing step of step S307, the bacterial-produced carbonized cellulose pulverized in step S305 and the bacterial-produced gel pulverized in step S306 are mixed.

[0085] The grinding process involves, for example, using a mixer, homogenizer, ultrasonic homogenizer, high-speed rotary shear mixer, colloid mill, roll mill, high-pressure jet disperser, rotary ball mill, vibrating ball mill, planetary ball mill, or attritor to powder or slurry the bacterial-produced gel and bacterial-produced carbonized cellulose. In this case, the bacterial-produced gel and bacterial-produced carbonized cellulose preferably have a secondary particle diameter of 100 nm to 5 mm, more preferably 1 μm to 1 mm. This is because grinding to a secondary particle diameter of 100 nm or less destroys the cocontinuous structure of the nanofibers, making it difficult to obtain sufficient binding strength and conductive paths, and increasing electrical resistance. If the secondary particle diameter is 5 mm or greater, the bacterial-produced gel, which functions as a binder, is not sufficiently dispersed, making it difficult to maintain the positive electrode in a sheet form.

[0086] Bacterially produced carbonized cellulose has high porosity and low density. When bacterially produced carbonized cellulose is pulverized alone, the resulting powder becomes airborne during and after pulverization, making it difficult to handle. Therefore, it is preferable to impregnate the bacterially produced carbonized cellulose with a solvent before pulverization. The solvent used here is not particularly limited, but aqueous solvents such as water (HO) can be used. Alternatively, organic solvents such as carboxylic acids, methanol (CHOH), ethanol (CHOH), propanol (CHOH), n-butanol, isobutanol, n-butylamine, dodecane, unsaturated fatty acids, ethylene glycol, heptane, hexadecane, isoamyl alcohol, octanol, isopropanol, acetone, and glycerin can be used. Two or more of these solvents can also be mixed.

[0087] It is also possible to simultaneously grind the bacterially produced gel and the bacterially produced carbonized cellulose, which is advantageous because the mixing step can be omitted.

[0088] The mixture produced by the above-described pulverization and mixing steps is in the form of a slurry. In the coating step of step S308, this mixed slurry is coated onto separator 203. In the drying step of step S309, the coated mixed slurry is dried. Through these steps, sheet-like positive electrode 201 can be processed into a desired shape.

[0089] In the drying step, a thermostatic oven, a vacuum dryer, an infrared dryer, a hot air dryer, or a suction dryer may be used. Rapid drying can be achieved by performing suction filtration using an aspirator or the like.

[0090] Alternatively, the mixed slurry may be dried, formed into a sheet, and then processed into a desired shape. For example, the resulting sheet of bacterially produced carbonized cellulose may be cut into a desired rectangle (e.g., 30 mm x 20 mm) using a punching blade, laser cutter, or the like to form the positive electrode 201. However, compared to the method of applying the mixed slurry, this increases the cost of materials such as scraps generated during the cutting process.

[0091] Instead of bacterially produced carbonized cellulose, cellulose nanofiber carbon may be used to produce the positive electrode 201. The manufacturing method using cellulose nanofiber carbon is similar to the manufacturing method using bacterially produced carbonized cellulose.

[0092] Specifically, as shown in the manufacturing method of FIG. 6 , in the freezing process, a solution containing cellulose nanofibers is frozen to obtain a frozen body. In the drying process, the frozen body is dried in a vacuum to obtain a dried body. In the carbonization process, the dried body is heated in a gas atmosphere in which cellulose does not burn, and carbonized. This results in cellulose nanofiber carbon. The cellulose nanofiber carbon produced by this manufacturing method has a fibrous network structure. This cellulose nanofiber carbon has a three-dimensional network structure with electrical conductivity and has physical properties, characteristics, and performance equivalent to bacterially produced carbonized cellulose. The cellulose nanofiber carbon is processed into a plate or sheet, which is then cut into the desired shape to form the positive electrode 201. Note that a catalyst may be supported on the cellulose nanofiber carbon, as in the process of FIG. 7 .

[0093] Alternatively, as in the manufacturing method shown in FIG. 8 , a slurry may be prepared from cellulose nanofiber carbon, and the slurry may be applied and dried to prepare the positive electrode 201. In the pulverization step, the cellulose nanofiber carbon prepared as described above is pulverized. In the mixing step, a cellulose nanofiber solution and the pulverized cellulose nanofiber carbon are mixed. This results in a slurry mixture. In the application step and drying step, this mixed slurry is applied to the separator 203, 203A or the conductive layer 204, 204A and dried.

[0094] (Method for Producing Negative Electrode) Next, a method for producing a negative electrode will be described.

[0095] FIG. 9 is a flowchart showing a method for manufacturing the negative electrode 202.

[0096] In the mixing step S401, a metal powder containing a predetermined amount of magnesium is mixed with a binder and a conductive additive. In the coating step S402, the mixed slurry obtained by mixing is coated onto the separator 203. In the drying step S403, the coated mixed slurry is dried. The negative electrode 202 can be produced through these steps. Compared to a method in which magnesium foil is cut into a predetermined shape, the manufacturing method of FIG. 9 can reduce material costs and produce a thin, flexible negative electrode 202.

[0097] In the mixing step, a slurry containing a metal powder containing magnesium, a binder, and a conductive additive is prepared using, for example, a magnetic stirrer, a stirrer, a mixer, a planetary ball mill, a vacuum stirring / degassing mixer, a mixer, a homogenizer, an ultrasonic homogenizer, a high-speed rotary shear type stirrer, a colloid mill, a roll mill, a high-pressure injection type disperser, a rotary ball mill, a vibrating ball mill, a planetary ball mill, or an attritor.

[0098] The magnesium-containing metal powder to be mixed can be pure magnesium or a magnesium-based alloy, such as AZ31, AZ31B, AZ61, AZ91, AMX601, AMX602, AZX611, AZX612, AM50, AM60, and LZ91.

[0099] The magnesium-containing metal powder can be synthesized by a conventional magnesium powder synthesis method, such as water atomization, gas atomization, centrifugal atomization, melt spinning, rotating electrode method, stamp milling, ball milling, mechanical alloying, oxide reduction, chloride reduction, hydrometallurgy, electrolysis, carbonyl reaction, and hydrogen plasma irradiation.

[0100] The particle size of the magnesium-containing metal powder is preferably 10 nm to 5 μm, and more preferably 20 nm to 2 μm. This is because if the particles are too large, they are less likely to contact each other when applied and dried, resulting in reduced electrical conductivity. If the particles are too small, an oxidation reaction may proceed, potentially deactivating the magnesium. In some cases, the oxidation reaction may proceed too rapidly, causing the magnesium metal to burn and leading to a fire.

[0101] The binder to be mixed may be any binder that binds particles together after the drying process of the slurry. Suitable binders include fluorine-free food additives such as gum arabic, sodium anginate, curdlan, carrageenan, agar, xanthan gum, chitosan, guar gum, konjac flour, cyclodextrin, gelatin, tamarind gum, tara gum, dextrin, starch, pregelatinized starch, pullulan, pectin, egg white, locust bean gum, propylene glycol, glycerin, soy protein, CMC, cellulose, and bacterially produced cellulose. The pulverized bacterially produced cellulose used to prepare the positive electrode 201 is suitable as a binder because its three-dimensionally entangled nanofiber structure firmly binds the magnesium-containing metal powder. Since bacterially produced cellulose is a necessary material for synthesizing the positive electrode 201, it is possible to use the same material for the positive electrode 201 and the negative electrode 202, which is cost-effective.

[0102] Examples of conductive additives to be mixed include bacterially produced carbonized cellulose, carbon powder, and conductive polymers, with conductive polymers that have high binding properties with magnesium-containing metal powders being preferred. Examples of conductive polymers include polyacetylene, which is an aliphatic conjugated system; poly(p-phenylene), which is an aromatic conjugated system; poly(p-phenylenevinylene), which is a mixed conjugated system; polythienylenevinylene, which is a heterocyclic conjugated system; polypyrrole, polythiophene, and polyethylenedioxythiophene (PEDOT); polyaniline, which is a heteroatom-containing conjugated system; polyacene and polyfluorene, which are multi-chain conjugated systems; and graphene, which is a two-dimensional conjugated system. PEDOT is preferred because of its excellent conductivity and environmental stability in a conductive state.

[0103] In the mixing process, it is advisable to add a solvent in addition to the magnesium-containing metal powder, binder, and conductive additive. The solvent is not particularly limited, but an aqueous solvent such as water (HO) can be used. Alternatively, organic solvents such as carboxylic acids, methanol (CHOH), ethanol (CHOH), propanol (CHOH), n-butanol, isobutanol, n-butylamine, dodecane, unsaturated fatty acids, ethylene glycol, heptane, hexadecane, isoamyl alcohol, octanol, isopropanol, acetone, and glycerin can be used. Two or more of these solvents may also be mixed.

[0104] In addition to the above manufacturing method, the negative electrode 202 can be formed by any known method. For example, the negative electrode 202 is produced by forming a metal magnesium foil into a predetermined shape.

[0105] (Examples and Evaluation Results) Next, examples in which the configuration of the battery section 2, the materials of the components of the battery section 2, and the manufacturing method were changed, and the evaluation results thereof will be described.

[0106] [Example 1] Fig. 10 is an exploded perspective view of the battery section 2 of Example 1, and Fig. 11 is a cross-sectional view of the battery section 2 of Example 1.

[0107] The battery module 2 of Example 1 includes a positive electrode 201, a negative electrode 202, and a separator 203. In Example 1, bacterially produced carbonized cellulose was used for the positive electrode 201. The preparation of the battery module 2 of Example 1 will be described below.

[0108] The bacterially produced carbonized cellulose used in the positive electrode 201 was obtained by the following method.

[0109] Nata de Coco (Fujicco), a bacterial cellulose gel produced by the acetic acid bacterium Acetobacter xylinum, was used as the bacterial gel. The bacterial gel was immersed in liquid nitrogen in a polystyrene foam box for 30 minutes to completely freeze. After completely freezing the bacterial gel, the frozen bacterial gel was placed on a petri dish and dried in a vacuum of 10 Pa or less using a freeze dryer (Tokyo Rikakikai Co., Ltd.) to obtain a bacterial xerogel. After drying in a vacuum, the bacterial xerogel was carbonized by baking at 1200°C for 2 hours in a nitrogen atmosphere to obtain bacterial carbonized cellulose.

[0110] The obtained bacterially produced carbonized cellulose was evaluated by XRD measurement, SEM observation, porosity measurement, tensile test, and BET specific surface area measurement. XRD measurement confirmed that this bacterially produced carbonized cellulose was a single phase of carbon (C, PDF card No. 01-071-4630). The PDF card No. is the card number of the Powder Diffraction File (PDF), a database compiled by the International Centre for Diffraction Data (ICDD). SEM observation confirmed that the bacterially produced carbonized cellulose was a bicontinuous structure consisting of continuously connected nanofibers with a diameter of 20 nm. The BET specific surface area of ​​the bacterially produced carbonized cellulose was measured using a BET device and found to be 830 m. 2 / g. The porosity of the bacterially produced carbonized cellulose was measured by mercury intrusion porosimetry and found to be over 99%. The porosity was calculated by modeling the pores as cylindrical from the pore size distribution determined by mercury intrusion porosimetry for the bacterially produced carbonized cellulose. The results of the tensile test confirmed that even when a strain of 80% was applied by tensile stress, the elastic region was not exceeded and the material returned to its shape before the stress was applied, demonstrating that the material retains excellent elasticity even after carbonization.

[0111] The positive electrode 201 was prepared by cutting the obtained bacterially produced carbonized cellulose into a rectangle of 30 mm x 20 mm using a punching blade, a laser cutter or the like.

[0112] The negative electrode 202 was prepared by cutting a commercially available metal magnesium foil (thickness: 200 μm, manufactured by Nilaco) into a rectangle of 30 mm×20 mm using a punching blade, a laser cutter, or the like.

[0113] The separator 203 was prepared by cutting commercially available cellulose cotton (Bencotton, manufactured by Asahi Kasei) into a rectangle of 30 mm x 50 mm using a punching blade, a laser cutter, or the like.

[0114] Using the above components, the battery part 2 was prepared as follows: The positive electrode 201 and the negative electrode 202 were placed on the separator 203 so that they did not come into contact with each other. Next, the positive electrode 201 and the negative electrode 202 were glued together with an acrylic adhesive, and the components were bonded together to obtain the battery part 2.

[0115] Fig. 12 is a plan view showing the configuration of the magnesium iontophoretic patch 1 of Example 1. The magnesium iontophoretic patch 1 shown in Fig. 12 has the same configuration as that shown in Fig. 1, and has a battery component 2 and an active ingredient 3 housed in isolation in a plastic pack 4.

[0116] A saturated aqueous solution of nicotinamide was used as the active ingredient 3. In Example 1, nicotinamide was used as the active ingredient, but the active ingredient is not limited to this.

[0117] The battery part 2 and the active ingredient 3 were housed separately in a plastic pack 4 as follows: First, the battery part 2 was inserted all the way into a 10 cm × 10 cm polyethylene film pack (manufactured by Nippon Matai) with one side open, and a heat seal was applied 5 cm from the back to form a partition wall 41, thereby sealing the battery part 2. Then, the active ingredient 3 was injected through the opening of the plastic pack 4 using a vacuum injection device (manufactured by Fine Flow Laboratory), and the opening was then heat sealed.

[0118] First, to initiate the battery reaction, the active ingredient storage section 43 in which the active ingredient 3 was sealed was folded in half along the fold line 47, and finger pressure was applied to break the partition wall 41, allowing the active ingredient 3 to soak fully into the battery section 2. As the active ingredient 3 soaks into the battery section 2, it also functions as an electrolyte, initiating the battery reaction. After confirming that the separator 203 of the battery section 2 was wet with the active ingredient 3, one end 44 of the plastic pack 4 sealing the battery section 2 was torn by hand, and the battery section 2 was removed.

[0119] In the evaluation test, as shown in FIG. 13 , the battery part 2 was attached to a test piece (human skin) 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated using TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0120] The measurement results of Example 1 will be described later together with the measurement results of Comparative Example 1.

[0121] 14 is a perspective view of a patch of Comparative Example 1, and Fig. 15 is a cross-sectional view of Comparative Example 1. Comparative Example 1 does not include a positive electrode 201, but includes a pair of negative electrodes 202 containing magnesium.

[0122] The negative electrode 202 and separator 203 of Comparative Example 1 were prepared as follows using the same materials as in Example 1. The negative electrode 202 was prepared by cutting two 30 mm x 20 mm rectangular pieces out of commercially available metal magnesium foil. The separator 203 was prepared by cutting a 30 mm x 50 mm rectangular piece out of commercially available cellulose-based cotton.

[0123] Using the above components, a patch of Comparative Example 1 was prepared as follows: Two negative electrodes 202 were placed on a separator 203 so that the negative electrodes 202 did not come into contact with each other. Next, the negative electrodes 202 were glued together using an acrylic adhesive, and the components were bonded together to obtain a patch of Comparative Example 1.

[0124] In the evaluation test, similarly to Example 1, the patch of Comparative Example 1 was impregnated with Active Ingredient 3, and the patch was then attached to a test piece 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated using TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0125] Figure 16 shows the measurement results for Example 1 and Comparative Example 1. Figure 16 is a diagram in which the secondary ion intensity of positive Mg ions is mapped on the cross section of the test piece. As is clear from the measurement results shown in Figure 16, magnesium ions were introduced in Example 1, whereas magnesium ions could not be measured in Comparative Example 1.

[0126] This is thought to be because in Example 1, the battery reaction was initiated by the positive electrode 201 and the negative electrode 202, and the magnesium in the negative electrode 202 was quickly ionized, whereas in Comparative Example 1, the battery reaction did not initiate.

[0127] Examples 2 to 5 and Comparative Examples 2 and 3 will be described below in order.

[0128] [Example 2] Fig. 17 is an exploded perspective view of the battery part 2 of Example 2, and Fig. 18 is a cross-sectional view of the battery part 2 of Example 2. Example 2 differs from Example 1 in that the positive electrode 201 and the negative electrode 202 are arranged so as to be in contact with each other.

[0129] In Example 2, the same materials as in Example 1 were used, and a positive electrode 201, a negative electrode 202, and a separator 203 were prepared as follows. The positive electrode 201 was prepared by cutting bacterially produced carbonized cellulose into a 30 mm x 25 mm rectangle. The negative electrode 202 was prepared by cutting commercially available metal magnesium foil into a 30 mm x 25 mm rectangle. The separator 203 was prepared by cutting commercially available cellulose-based cotton into a 30 mm x 50 mm rectangle.

[0130] Using the above components, the battery module 2 of Example 2 was prepared as follows. The positive electrode 201 and the negative electrode 202 were arranged side by side on the separator 203 so that the positive electrode 201 and the negative electrode 202 were in contact with each other. Next, the positive electrode 201 and the negative electrode 202 were glued together using an acrylic adhesive, and the components were bonded together to obtain the battery module 2.

[0131] In the evaluation test, similarly to Example 1, the active ingredient 3 was impregnated into the battery part 2 of Example 2, and then the battery part 2 was attached to the test piece 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated by TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0132] The amount of magnesium ions permeated in Example 2 was equivalent to that in Example 1.

[0133] This is thought to be because even if the positive electrode 201 and the negative electrode 202 are in contact with each other, the battery reaction starts and the magnesium in the negative electrode 202 is ionized.

[0134] 19 is an exploded perspective view of the battery module 2 of Example 3, and Fig. 20 is a cross-sectional view of the battery module 2 of Example 3. Example 3 differs from Examples 1 and 2 in that the positive electrode 201 and the negative electrode 202 are arranged to overlap each other.

[0135] In Example 3, the same materials as in Example 1 were used, and a positive electrode 201, a negative electrode 202, and a separator 203 were prepared as follows. The positive electrode 201 was prepared by cutting two 30 mm x 20 mm rectangular pieces of bacterially produced carbonized cellulose. The negative electrode 202 was prepared by cutting two 30 mm x 20 mm rectangular pieces of commercially available metal magnesium foil. The separator 203 was prepared by cutting a 30 mm x 50 mm rectangular piece of commercially available cellulose-based cotton.

[0136] Using the above components, the battery module 2 of Example 3 was prepared as follows. The positive electrode 201 and the negative electrode 202 were stacked and arranged on both ends of the separator 203. At this time, the positive electrodes 201 and the negative electrodes 202 were arranged so as not to contact each other. Next, the positive electrode 201 and the negative electrode 202 were glued together using an acrylic adhesive, and the components were bonded together to obtain the battery module 2.

[0137] In the evaluation test, similarly to Example 1, the active ingredient 3 was impregnated into the battery part 2 of Example 3, and then the battery part 2 was attached to the test piece 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated by TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0138] The amount of magnesium ions permeated in Example 3 was superior to that in Examples 1 and 2.

[0139] This is thought to be because the positive electrode 201 and the negative electrode 202 were in contact over a larger area than in Example 2, which promoted the ionization of magnesium.

[0140] [Example 4] Fig. 21 is an exploded perspective view of the battery part 2 of Example 4, and Fig. 22 is a cross-sectional view of the battery part 2 of Example 4. Example 4 differs from Examples 1 to 3 in that a mixed electrode 205 in which a positive electrode material and a negative electrode material are mixed is used.

[0141] The positive electrode material was produced by steps S301 to S307 of the production method shown in Figure 8. Bacterially produced carbonized cellulose was obtained by the same method as in Example 1. In the crushing and mixing steps, the bacterially produced carbonized cellulose was impregnated with water, and then the bacterially produced gel and the bacterially produced carbonized cellulose in a weight ratio of 1:1 were stirred for 12 hours using a homogenizer (manufactured by SMT).

[0142] The negative electrode material was manufactured by the following method. The negative electrode used flame-retardant magnesium AZX612 (manufactured by Gonda Metal), which contains magnesium, 1 wt% zinc, 2 wt% calcium, and 6 wt% aluminum. This flame-retardant magnesium AZX612 was irradiated with hydrogen plasma using a metal nanoparticle manufacturing device (manufactured by Attotec) to synthesize flame-retardant magnesium AZX612 nanoparticles. SEM observation of these nanoparticles revealed an average particle diameter of approximately 100 nm. Furthermore, ICP emission spectrometry confirmed that no compositional deviation occurred even after the particles were formed.

[0143] The separator 203 was prepared by cutting commercially available cellulose cotton (Bencotton, manufactured by Asahi Kasei) into a rectangle of 30 mm x 50 mm using a punching blade, a laser cutter, or the like.

[0144] The positive electrode material and the negative electrode material were mixed and applied to the separator 203 to obtain a mixed electrode 205. Specifically, the positive electrode material and the negative electrode material were mixed and stirred for 12 hours using a homogenizer (manufactured by SMT) to obtain a mixed electrode slurry. Using a squeegee, the mixed electrode slurry was applied to two locations on both ends of the separator 203 in a thickness of 3 mm and a size of 30 mm x 20 mm. The separator 203 to which the mixed electrode slurry had been applied was dried in a thermostatic bath at 60°C for 24 hours to obtain a mixed electrode 205.

[0145] In the evaluation test, similarly to Example 1, the active ingredient 3 was impregnated into the battery part 2 of Example 4, and then the battery part 2 was attached to the test piece 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated by TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0146] Example 4 showed the same amount of magnesium ions permeated as Example 3. Since the mixed electrode 205 is obtained by applying the mixed electrode slurry to the battery part 2 of Example 4, an inexpensive and excellent magnesium iontophoretic patch 1 capable of permeating magnesium ions can be realized.

[0147] Example 5 Example 5 has the same structure as Example 4, but differs from Example 4 in that cellulose nanofiber carbon is used as the positive electrode material.

[0148] The cellulose nanofiber carbon used as the positive electrode material was obtained using the following method. First, 1 g of cellulose nanofiber (manufactured by Nippon Paper Industries Co., Ltd.) was mixed with 10 g of ultrapure water in a homogenizer (manufactured by SMT) for 12 hours to obtain a cellulose nanofiber solution in which the cellulose nanofibers were dispersed. The test tube containing the cellulose nanofiber solution was immersed in liquid nitrogen for 30 minutes to completely freeze the cellulose nanofiber solution. The frozen cellulose nanofiber solution was placed on a petri dish and dried in a freeze dryer (manufactured by Tokyo Rikakikai Co., Ltd.) under a vacuum of 10 Pa or less to obtain a dried cellulose nanofiber. After drying in a vacuum, the cellulose nanofibers were carbonized by baking at 600°C for 2 hours in a nitrogen atmosphere to obtain cellulose nanofiber carbon.

[0149] XRD measurement confirmed that this cellulose nanofiber carbon was a single phase of carbon (C, PDF card No. 01-071-4630). SEM observation confirmed that the cellulose nanofiber carbon was a bicontinuous structure of continuously connected nanofibers with a diameter of 70 nm. The BET specific surface area of ​​the cellulose nanofiber carbon was measured using a BET device and found to be 690 m2 / g. The porosity of the cellulose nanofiber carbon was measured using mercury intrusion porosimetry and found to be greater than 99%. Tensile test results confirmed that even when a 30% strain was applied by tensile stress, the elastic region was not exceeded and the carbon nanofiber recovered to its original shape before the stress was applied, demonstrating excellent elasticity even after carbonization.

[0150] The method for forming the mixed electrode 205 is the same as in the fourth embodiment.

[0151] In the evaluation test, similarly to Example 1, the active ingredient 3 was impregnated into the battery part 2 of Example 5, and then the battery part 2 was attached to the test piece 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated by TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0152] Example 5 showed the same amount of magnesium ion penetration as Example 4.

[0153] This is thought to be because the cellulose nanofiber carbon used in the positive electrode has an excellent specific surface area, similar to bacterially produced carbonized cellulose, and the fibrous network structure of the cellulose nanofiber carbon suppresses battery overvoltage.

[0154] Comparative Example 2 has the same structure as Example 1, but differs from Example 1 in that the positive electrode 201 is made of carbon (Ketjen Black EC600JD), which is known as an air electrode for a general magnesium-air battery.

[0155] The positive electrode 201 of Comparative Example 2 was obtained by the following method. Ketjen black powder (manufactured by Lion) and polytetrafluoroethylene (PTFE) powder (manufactured by Daikin) were thoroughly crushed and mixed in a weight ratio of 50:30:20 using a crushing machine, and the mixture was roll-formed to prepare a sheet-like electrode with a thickness of 0.5 mm. The sheet-like electrode was cut into a piece of 30 mm x 20 mm to obtain the positive electrode 201 of Comparative Example 2.

[0156] The manufacturing method of the battery part of Comparative Example 2 was the same as that of Example 1 except for the positive electrode 201 .

[0157] In the evaluation test, similarly to Example 1, the active ingredient 3 was impregnated into the battery portion of Comparative Example 2, and then the battery portion was attached to the test piece 600 for 1 hour to allow magnesium ions to penetrate into the test piece 600, and the skin permeability of the magnesium ions was evaluated using TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0158] Comparative Example 2 showed the same performance as Example 1. However, when the magnesium iontophoresis patch 1 of Comparative Example 2 was observed after the measurement, a part of the positive electrode 201 had crumbled, the active ingredient had turned black, and furthermore, the test piece 600 was found to be soiled with carbon powder.

[0159] Comparative Example 3 Comparative Example 3 is a test specimen in which ordinary cotton is impregnated with a saturated aqueous solution of magnesium chloride as an active ingredient.

[0160] A commercially available cellulose cotton was cut into a rectangle of 30 mm x 50 mm and impregnated with a saturated aqueous solution of magnesium chloride to obtain a patch of Comparative Example 3.

[0161] In the evaluation test, similarly to Example 1, the patch of Comparative Example 3 was impregnated with Active Ingredient 3, and the patch was then attached to the test piece 600 for 1 hour to allow magnesium ions to penetrate the test piece 600, and the skin permeability of the magnesium ions was evaluated using TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0162] It was found that the amount of magnesium permeated in Comparative Example 3 was smaller than that in Example 1.

[0163] This is thought to be because in Example 1, the use of a battery reaction promoted the penetration of magnesium ions.

[0164] As described above, the magnesium iontophoretic patch 1 of this embodiment includes a battery section 2 including a positive electrode 201, a negative electrode 202, and a separator 203, and an active ingredient 3 accommodated so as not to come into contact with the battery section 2. The positive electrode 201 contains carbonized cellulose with a three-dimensional network structure, and the negative electrode 202 contains magnesium. The separator 203 does not contain an electrolyte, and when using the magnesium iontophoretic patch 1, the positive electrode 201, the negative electrode 202, and the separator 203 are impregnated with the active ingredient 3, which acts as an electrolyte, to initiate a battery reaction. This allows the magnesium in the negative electrode 202 to be rapidly ionized, resulting in an excellent magnesium iontophoretic effect.

[0165] According to this embodiment, by using bacterially produced carbonized cellulose or cellulose nanofiber carbon for the positive electrode 201 of the battery part 2, the environmental load can be reduced and the battery part 2 can be easily disposed of in daily life.

[0166] In this embodiment, the battery portion 2 and the active ingredient 3 are housed together in a separate plastic pack 4, but the battery portion 2 and the active ingredient 3 may be housed and stored separately.

[0167] It should be noted that the present disclosure is not limited to the embodiments described above, and it is clear that many modifications and combinations can be made by a person having ordinary knowledge in the art within the technical concept of the present disclosure.

[0168] DESCRIPTION OF SYMBOLS 1...Magnesium iontophoresis patch 2...Battery section 201...Positive electrode 202...Negative electrode 203...Separator 205...Mixed electrode 3...Active ingredient 4...Plastic pack 41...Partition 42...Battery section storage section 43...Active ingredient storage section

Claims

1. A magnesium iontophoresis patch to be attached to biological tissue for use, comprising: a battery section having a positive electrode, a negative electrode, and a separator; and an active ingredient contained so as not to come into contact with the battery section, wherein the positive electrode contains carbonized cellulose with a three-dimensional network structure, the negative electrode contains magnesium, and the separator does not contain an electrolyte, and when the magnesium iontophoresis patch is used, the active ingredient which acts as an electrolyte is impregnated into the positive electrode, the negative electrode, and the separator to initiate a battery reaction.

2. The magnesium iontophoretic patch according to claim 1, wherein the positive electrode and the negative electrode are arranged to be in contact with each other.

3. The magnesium iontophoretic patch according to claim 1, comprising a mixed electrode in which the positive electrode and the negative electrode are mixed.

Images