Fluid injection device

Abstract

Provided is a fluid injection device (10) capable of efficiently administering a drug. A first transport body (11) has a first transport flow path through which a first fluid (21) flows, and a second transport body (12) has a second transport flow path through which a second fluid (22) flows. Positive-side microneedles (13) provided to the first transport body (11) have a first opening and a first flow path to which a positive charge is fixed. Negative-side microneedles (14) provided to the second transport body (12) have a second opening and a second flow path to which a negative charge is fixed. When a current / voltage application means (15) applies a current or voltage between a first electrode (24) disposed in the first transport flow path and a second electrode (25) disposed in the second transport flow path, an ion current flows through the first fluid (21) and the second fluid (22), and the first fluid (21) flows from the first opening toward the outside and the second fluid (22) flows from the second opening toward the outside by electroosmotic flow.

Description

Fluid Injection Device

[0001] The present invention relates to a fluid injection device.

[0002] Iontophoresis is a conventional drug administration method that promotes drug penetration by passing a small electric current through the body. Iontophoresis can administer drugs directly into blood vessels or affected areas, which has the advantage of allowing drugs to be administered more efficiently and minimizing side effects compared to conventional oral administration.

[0003] Iontophoresis is widely recognized as being particularly effective in promoting the penetration of drugs through the skin (see, for example, Non-Patent Document 1), and various devices have been developed, from stationary types requiring an external power source to portable types and patch types that are attached to the body surface. Iontophoresis is also considered effective for administering drugs to organs and tumors in addition to the skin, and it has been reported that it can significantly improve the efficiency of administering anticancer drugs to cancer tumors (see, for example, Non-Patent Document 2).

[0004] The penetration-enhancing effect of iontophoresis is thought to be due not only to the electrophoresis of drugs but also to the "electroosmotic flow" that occurs in the skin and tissues. Because drug molecules are small in quantity compared to electrolyte ions, electrophoretic movement is very small, and electroosmotic flow is thought to often dominate overall movement. However, because skin and tissues in the body have a slight negative charge, electroosmotic flow occurs only in the direction of cation movement. For this reason, penetration is promoted only at the positive electrode; at the negative electrode, a flow occurs in the opposite direction, drawing out body fluids, which may hinder drug penetration.

[0005] The present inventors have developed a porous microneedle with a fixed negative charge by chemical modification to generate a large electroosmotic flow on the positive electrode side (see, for example, Non-Patent Documents 3 and 4, or Patent Document 1). It has been reported that this microneedle can deliver a drug under the skin regardless of the charge of the drug, i.e., regardless of the direction of electrophoresis.

[0006] In response to this, the present inventors have developed an electroosmotic flow pump that uses a material with a fixed negative charge on the positive electrode side and a material with a fixed positive charge on the negative electrode side, which is capable of supplying drugs to the surface of the skin or tissue using electroosmotic flow from both the positive and negative electrode sides without interfering with drug penetration on the negative electrode side (see, for example, Patent Document 2).

[0007] Kenji Sugibayashi, "Iontophoresis: A New Transdermal Administration Method," Pharmacia, 2001, Vol. 37, No. 5, pp. 385-387; James D. Byrne et al., "Local iontophoretic administration of cytotoxic therapies to solid tumors," Science Translational Medicine, 2015, 7, 273ra14; Shinya Kusama et al., "Transdermal Electroosmotic Flow Generated by a Porous Microneedle Array Patch," Nature Communications, 2021, 12, 658; Hiroya Abe et al., "Porous Microneedle Patch for Electroosmosis-Promoted Transdermal Delivery of Drugs and Vaccines," Advanced NanoBiomedical Research, 2022, 2, 2100066

[0008] JP 2022-83780 A JP 2023-69170 A

[0009] The electroosmotic flow pump described in Patent Document 2 can deliver a drug to the surface of the skin or tissue from both the positive and negative poles, thereby increasing the amount of drug administered. Furthermore, by delivering different drugs from the positive and negative poles, two types of drugs can be administered simultaneously. Thus, the electroosmotic flow pump described in Patent Document 2 can deliver drugs more efficiently than pumps that only use electroosmotic flow from the positive pole. However, the development of pumps that can deliver drugs even more efficiently is anticipated.

[0010] The present invention has been made in light of these problems, and has an object to provide a fluid injection device that can administer medicine more efficiently.

[0011] In order to achieve the above object, the fluid injection device according to the present invention comprises a first transporter having a first transport flow path through which a first fluid flows, a second transporter having a second transport flow path through which a second fluid flows, a first opening provided at a tip portion, and a first flow path in which a positive charge is fixed and which communicates with the first opening, a positive microneedle provided in the first transporter so that the first flow path communicates with the first transport flow path, and a second opening provided at a tip portion, and a second flow path in which a negative charge is fixed and which communicates with the second opening, a negative microneedle provided in the second transporter so that the second flow path communicates with the second transport flow path. a first electrode disposed in the first transport flow path, and a second electrode disposed in the second transport flow path, and a current / voltage application means provided so as to be able to apply a current or a voltage between the first electrode and the second electrode, wherein when a current or a voltage is applied between the first electrode and the second electrode by the current / voltage application means, an ionic current flows through the first fluid in the first flow path and the second fluid in the second flow path, and electroosmotic flow causes the first fluid to flow outward from the first opening and the second fluid to flow outward from the second opening.

[0012] The fluid injection device according to the present invention is configured such that a first transporter is provided with a positive microneedle, a second transporter is provided with a negative microneedle, and a first fluid flows outward from a first opening of the positive microneedle and a second fluid flows outward from a second opening of the negative microneedle due to electroosmotic flow, thereby enabling the first fluid and the second fluid to be directly injected subcutaneously or into tissue. Therefore, by using fluids containing a drug as the first fluid and the second fluid, the drug can be administered more efficiently than with conventional electroosmotic flow pumps that do not have microneedles.

[0013] When a fluid containing a drug is used as the first fluid and the second fluid, the fluid injection device according to the present invention can supply the drug subcutaneously or into tissue from both the first opening of the positive microneedle and the second opening of the negative microneedle, thereby increasing the drug dosage by up to twice as much as when supplying the drug from either one of them. Furthermore, by using different drugs in the first fluid and the second fluid, two types of drugs can be administered simultaneously.

[0014] The fluid injection device according to the present invention applies a current or voltage to the first electrode as negative and the second electrode as positive by means of a current / voltage application means, thereby passing an ionic current through the first fluid in the first flow path and the second fluid in the second flow path, causing the first fluid to flow outward from the first opening and the second fluid to flow outward from the second opening by electroosmotic flow. The fluid injection device according to the present invention can control the flow rate of the generated electroosmotic flow by adjusting the current or voltage applied by the current / voltage application means, and has excellent controllability over the amount of discharge of the first fluid and the second fluid.

[0015] In the fluid injection device according to the present invention, the positive microneedle and the negative microneedle may be made of a porous body, and the first and second flow paths may extend in a network-like manner through the voids in the porous body. The positive microneedle and the negative microneedle may each consist of one or more. When multiple microneedles are used, they may form a microneedle array. The positive microneedle and the negative microneedle may each have a sharp tip so that they can be inserted into a target object such as skin or tissue to directly inject the first and second fluids into the target object. Alternatively, the tip may be curved or flat so that they can spread the surface of the target object and allow the first and second fluids to penetrate into the target object. The first and second openings may each consist of one or more.

[0016] In the fluid injection device according to the present invention, the positive microneedle may be made of any material capable of immobilizing a positive charge in the first flow path, and the negative microneedle may be made of any material capable of immobilizing a negative charge in the second flow path. In this case, the positive and negative microneedles may be made of, for example, a hydrogel material, a porous resin, an oxide, a metal, a biodegradable material, or the like. More specifically, the positive microneedle may have a higher mobility of anions than cations when a fluid is introduced into the first flow path. For example, the positive microneedle may have a positive charge immobilized on the wall surface of the first flow path, a positive charge embedded in the surface, or may be made of a hydrogel containing positively charged functional groups. Furthermore, the negative microneedle may have a higher mobility of cations than anions when a fluid is introduced into the second flow path. For example, the negative microneedle may have a negative charge immobilized on the wall surface of the second flow path, a negative charge embedded in the surface, or may be made of a hydrogel containing negatively charged functional groups.

[0017] In the fluid injection device according to the present invention, the first fluid and the second fluid are preferably fluids containing a drug, and may be different fluids or the same fluid. In the fluid injection device according to the present invention, the first electrode is preferably inserted into the first transport channel from the other end side of the first transporter, and the second electrode is preferably inserted into the second transport channel from the other end side of the second transporter.

[0018] In the fluid injection device according to the present invention, the positive microneedle and the negative microneedle are preferably arranged adjacent to each other. In this case, the entire device can be configured compactly, and miniaturization can be achieved. In this case, it is also preferable that the tips of the positive microneedle and the negative microneedle protrude on the same side, so that they can be easily inserted into or pressed against a target object simultaneously.

[0019] In the fluid injection device according to the present invention, the first transporter may be elongated and the first transport channel may extend from one end to the other end, the second transporter may be elongated and the second transport channel may extend from one end to the other end, the positive microneedle may be provided at one end of the first transporter, and the negative microneedle may be provided at one end of the second transporter. In this case, the entire device can be made elongated, thereby achieving miniaturization. In addition, in this case, it is preferable that the positive microneedle is provided so that its tip protrudes from the one end of the first transporter in the extension direction of the first transporter, and the negative microneedle is provided so that its tip protrudes from the one end of the second transporter in the extension direction of the second transporter. This allows the positive microneedle and the negative microneedle to be easily pierced or pressed against the target by moving one end of the first transporter and one end of the second transporter toward the target in their respective extension directions.

[0020] In the fluid injection device according to the present invention, the first transporter and the second transporter may be configured separately, or may be provided integrally. In the case where they are provided integrally, the entire device can be configured compactly, which allows for miniaturization and makes the device easier to handle.

[0021] The fluid injection device according to the present invention may have a rigid tubular body integrally constituting the first transporter and the second transporter, the tubular body being elongated and having two hollow portions extending from one end to the other, one of which forms the first transport flow path and the other of which forms the second transport flow path. In this case, the tubular body can be held in one hand and the positive microneedle and the negative microneedle can be pierced or pressed against a target object, making it easy to handle.

[0022] In the fluid injection device according to the present invention, the first transporter and the second transporter may each be a flexible tube. In this case, for example, by using a catheter as the tube, tissue inside a living body can be easily accessed and a drug or the like can be directly injected into the tissue. This allows, for example, an anticancer drug to be administered directly to a tumor, resulting in effective treatment.

[0023] According to the present invention, it is possible to provide a fluid injection device that can administer a drug more efficiently.

[0024] FIG. 1 is a cross-sectional view showing a fluid injection device according to an embodiment of the present invention. FIG. 1 is a perspective view showing an array of positive and negative microneedles of a fluid injection device according to an embodiment of the present invention, and FIG. 2 is an enlarged side view of one negative microneedle. FIG. 2 is a cross-sectional view showing a test method for a test of electroosmotic flow generation using a Franz cell with a horizontal capillary for the positive and negative microneedles of a fluid injection device according to an embodiment of the present invention. FIG. 3 is a graph showing the relationship between current density and flow rate for the positive microneedle ("positive charge fixed" in the figure) and the negative microneedle ("negative charge fixed" in the figure), which is the test result. FIG. 1 is a cross-sectional view showing a test method for a test of electroosmotic flow generation using a Franz cell for the positive and negative microneedles of a fluid injection device according to an embodiment of the present invention. 2 ") and the negative microneedle ("0.5 mA / cm 2 10 is a graph showing the time course of the molecular transport amount of FITC-OVA (Transported OVA) in a test in which dextran was injected into a pig skin section using a fluid injection device according to an embodiment of the present invention. (a) A perspective view showing the test method. (b) A graph showing the time course of the test in which dextran was injected into a pig skin section using a fluid injection device according to an embodiment of the present invention. 2 (c) Bright light and (d) fluorescent micrographs of a pig skin section with a positive microneedle at −0.5 mA / cm 21A and 1B are micrographs of a pig skin section taken under bright light and (e) under fluorescent light, respectively, when a current of 0 mA is applied to the fluid injection device according to an embodiment of the present invention.

[0034] Fig. 1B is a side view showing fluorescence from dextran in the glangum gel, (a) before the test, (b) when the device is left for 20 minutes without applying current (0 mA), and (c) when a current of 2.5 mA is applied between the negative electrode (anode) on the positive microneedle side and the positive electrode (cathode) on the negative microneedle side for 20 minutes, in a test of injecting dextran into the glangum gel using the fluid injection device according to an embodiment of the present invention.

[0035] Fig. 1C is a perspective view of a stamp-type device according to an embodiment of the present invention, (a) an exploded perspective view, (b) an enlarged perspective view of one end of the tubular body, and (c) a perspective view showing the device in use when held in one hand. 8 is a side view showing the state of penetration of rhodamine B and methylene blue into glangum gel when a current of 2.0 mA is applied between the first electrode and the second electrode for 20 minutes, (a) before the test, and (b) when a current of 2.0 mA is applied between the first electrode and the second electrode, in a test of injecting rhodamine B and methylene blue into glangum gel using the stamp-type device shown in Fig. 7. 9 is a perspective view showing the state before and during fluid injection, (b) a graph showing the absorbance (optical density) for each combination of positive and negative microneedles, in a test of inoculating a vaccine model (OVA) into mice using the stamp-type device shown in Fig. 7. 9 shows an example of a catheter-type device of a fluid injection device according to an embodiment of the present invention, (a) an enlarged perspective view of one end of a tube, and (b) a side view showing the state in use.

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings and examples. Figures 1 to 10 show a fluid injection device according to an embodiment of the present invention. As shown in Figure 1, the fluid injection device 10 has a first transporter 11, a second transporter 12, a positive microneedle 13, a negative microneedle 14, and a current / voltage application means 15.

[0026] The first transport body 11 is elongated and has a first transport flow path (not shown) extending from one end to the other end thereof. The first transport body 11 is configured to allow a first fluid 21 to flow through the first transport flow path. The second transport body 12 is elongated and has a second transport flow path (not shown) extending from one end to the other end thereof. The second transport body 12 is configured to allow a second fluid 22 to flow through the second transport flow path. The first transport body 11 and the second transport body 12 may be configured separately from each other, or may be provided integrally.

[0027] The first fluid 21 flowed through the first transport channel and the second fluid 22 flowed through the second transport channel may be any fluids to be injected into a subject, but when the subject is skin or tissue inside a living body, it is preferable that each of them is a fluid containing a drug. The first fluid 21 and the second fluid 22 may be different fluids or the same fluid.

[0028] As shown in FIG. 2 , the positive microneedle 13 and the negative microneedle 14 are each made of a porous material, have a conical shape, and have a flange portion 23 around the rear end of the base of the cone. The positive microneedle 13 has at least a first opening (not shown) at its tip and a first flow path (not shown) that has a fixed positive charge and is connected to the first opening. The negative microneedle 14 has at least a second opening (not shown) at its tip and a second flow path (not shown) that has a fixed negative charge and is connected to the second opening. The first flow path and the second flow path extend in a network-like manner through the voids in the porous material. In a specific example shown in FIG. 2 , the tip heights of the positive microneedle 13 and the negative microneedle 14 are 300 μm, and the height of the flange portion 23 is 300 μm.

[0029] As shown in Fig. 1, the positive microneedle 13 is provided at one end of the first transporter 11 so that the first flow path communicates with the first transport flow path. The positive microneedle 13 is provided so that its tip protrudes from one end of the first transporter 11 in the extension direction of the first transporter 11. The negative microneedle 14 is provided at one end of the second transporter 12 so that the second flow path communicates with the second transport flow path. The negative microneedle 14 is provided so that its tip protrudes from one end of the second transporter 12 in the extension direction of the second transporter 12. The positive microneedle 13 and the negative microneedle 14 are arranged adjacent to each other so that their respective tips protrude on the same side.

[0030] The positive microneedle 13 and the negative microneedle 14 may each consist of a plurality of microneedles, as shown in FIG. 2, or may each consist of a single microneedle. When a plurality of microneedles are used, they may form a microneedle array. Furthermore, as shown in FIG. 2, the positive microneedle 13 and the negative microneedle 14 may each have a pointed tip so that they can be inserted into a target object and directly inject the first fluid 21 and the second fluid 22 into the target object. However, the tip may also have a curved or flat surface so that they can spread the surface of the target object and allow the first fluid 21 and the second fluid 22 to penetrate into the target object. Furthermore, the first opening and the second opening may each consist of a single opening or a plurality of openings.

[0031] The positive microneedle 13 may be made of any material capable of immobilizing a positive charge in the first flow path, and the negative microneedle 14 may be made of any material capable of immobilizing a negative charge in the second flow path. The positive microneedle 13 and the negative microneedle 14 may be made of, for example, a hydrogel material, a porous resin, an oxide, a metal, a biodegradable material, or the like. More specifically, the positive microneedle 13 may have a higher mobility of anions than cations when a fluid is introduced into the first flow path. For example, the positive microneedle 13 may have a positive charge immobilized on the wall surface of the first flow path, a positive charge embedded in the surface, or may be made of a hydrogel containing positively charged functional groups. The negative microneedle 14 may have a higher mobility of cations than anions when a fluid is introduced into the second flow path. For example, the negative microneedle 14 may have a negative charge immobilized on the wall surface of the second flow path, a negative charge embedded in the surface, or may be made of a hydrogel containing negatively charged functional groups.

[0032] Here, the hydrogel material refers to a material that forms a hydrogel when dispersed in water (dispersion medium). Examples of hydrogel materials include natural polymers such as agar, gelatin, agarose, xanthan gum, gellan gum, sclerotium gum, gum arabic, tragacanth gum, karaya gum, cellulose gum, tamarind gum, guar gum, locust bean gum, glucomannan, chitosan, carrageenan, quince seed, galactan, mannan, starch, dextrin, curdlan, casein, pectin, collagen, fibrin, peptides, chondroitin sulfates such as sodium chondroitin sulfate, hyaluronic acid (mucopolysaccharides) and hyaluronates such as sodium hyaluronate, alginic acid, alginate such as sodium alginate, and alginates such as calcium alginate, and derivatives thereof; cellulose derivatives such as methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and carboxymethylcellulose, and salts thereof; polyacrylic acid, polymethacrylic acid, poly(methylcellulose), ... Examples of suitable polymers include poly(meth)acrylic acids and salts thereof, such as sodium dimethacrylate and acrylic acid-alkyl methacrylate copolymers; synthetic polymers such as polyvinyl alcohol, polyhydroxyethyl methacrylate, polyacrylamide, poly(N-isopropylacrylamide), polyvinylpyrrolidone, polystyrene sulfonic acid, polyethylene glycol, carboxyvinyl polymers, alkyl-modified carboxyvinyl polymers, maleic anhydride copolymers, polyalkylene oxide resins, crosslinked products of poly(methyl vinyl ether-alt-maleic anhydride) and polyethylene glycol, crosslinked products of polyethylene glycol, N-vinylacetamide crosslinked products, acrylamide crosslinked products, and crosslinked products of starch-acrylate graft copolymers; silicones; interpenetrating network structure hydrogels and semi-interpenetrating network structure hydrogels; poly(2-hydroxyethyl methacrylate), poly(2-acrylamido-2-methylpropanesulfonic acid); and mixtures of two or more of these.Among these, from the viewpoints of load-bearing capacity and biocompatibility, preferred materials for constituting the hydrogel are collagen, glucomannan; carboxymethylcellulose, sodium carboxymethylcellulose; polyacrylic acid, sodium polyacrylate; interpenetrating network structure hydrogels, and semi-interpenetrating network structure hydrogels. Furthermore, from the viewpoints of obtaining excellent mechanical strength and excellent biocompatibility, a crosslinked product of poly(methyl vinyl ether-alt-maleic anhydride) and polyethylene glycol is preferred, and further, from the viewpoint of ensuring the electrical neutrality of the hydrogel, crosslinked polyethylene glycol is preferred.

[0033] Furthermore, examples of hydrogel materials having a fixed charge (positive or negative charge) include gel materials in which functional groups having a fixed charge have been introduced into hydrogel materials having no fixed charge, and gel materials that are polymers (polymers) containing monomer units having a fixed charge. Among these, gel materials that are polymers (polymers) containing monomer units having a fixed charge are preferred, and copolymers of a non-charged monomer and a monomer having a fixed charge are more preferred.

[0034] Resins include polycarbonate, acrylonitrile-butadiene-styrene (ABS) resin, phenolic resin, acrylic resin, and methacrylic resin (such as polyglycidyl methacrylate resin). Oxides include inorganic oxides and their derivatives, such as silicon oxide, tin oxide, zirconia oxide, titanium oxide, niobium oxide, tantalum oxide, aluminum oxide, tungsten oxide, hafnium oxide, and zinc oxide. Metals include nickel, iron, and alloys thereof. Biodegradable materials include polylactic acid-glycolic acid copolymer (PLGA), PLGA-based composites, beta-tricalcium phosphate, calcium carbonate, polycaprolactone, polydioxanone, hydroxyapatite, polyethylene glycol, and magnesium alloys. The positive microneedle 13 and the negative microneedle 14 may be made of a combination of two or more of the materials listed above.

[0035] The current / voltage application means 15 has a first electrode 24 arranged in the first transport flow path and a second electrode 25 arranged in the second transport flow path, and is configured to be able to apply a current or voltage between the first electrode 24 and the second electrode 25. The first electrode 24 is inserted into the first transport flow path from the other end side of the first transporter 11, and the second electrode 25 is inserted into the second transport flow path from the other end side of the second transporter 12. More specifically, the current / voltage application means 15 is configured to apply a current or voltage with the first electrode 24 as negative and the second electrode 25 as positive. As a result, in the fluid injection device 10, when the current / voltage application means 15 applies a current or voltage between the first electrode 24 and the second electrode 25, an ionic current flows through the first fluid 21 in the first flow path and the second fluid 22 in the second flow path, and electroosmotic flow causes the first fluid 21 to flow outward from the first opening and the second fluid 22 to flow outward from the second opening.

[0036] Next, the operation will be described. The fluid injection device 10 is used as follows. First, the positive microneedle 13 provided at one end of the first transporter 11 and the negative microneedle 14 provided at one end of the second transporter 12 are inserted into or pressed against the skin or tissue inside the living body. In this state, a current or voltage is applied between the first electrode 24 and the second electrode 25 by the current / voltage application means 15. This causes an ionic current to flow through the first fluid 21 in the first flow path and the second fluid 22 in the second flow path, causing the first fluid 21 to flow outward from the first opening of the positive microneedle 13 and the second fluid 22 to flow outward from the second opening of the negative microneedle 14 due to electroosmotic flow. This allows the fluid injection device 10 to directly inject the first fluid 21 and the second fluid 22 into the subcutaneous tissue or tissue. Therefore, by using fluids containing a drug as the first fluid 21 and the second fluid 22, the drug can be administered more efficiently than with conventional electroosmotic pumps that do not have microneedles.

[0037] Furthermore, by using fluids containing a drug as the first fluid 21 and the second fluid 22, the fluid injection device 10 can supply the drug subcutaneously or into tissue from both the first opening of the positive microneedle 13 and the second opening of the negative microneedle 14, thereby increasing the drug dosage by up to twice as much as when supplying the drug from either one of them. Furthermore, by using different drugs for the drug contained in the first fluid 21 and the drug contained in the second fluid 22, two types of drugs can be administered simultaneously.

[0038] The fluid injection device 10 can control the flow rate of the generated electroosmotic flow by adjusting the current or voltage applied by the current / voltage application means 15, and has excellent control over the amount of discharge of the first fluid 21 and the second fluid 22. Furthermore, in the fluid injection device 10, the positive microneedle 13 and the negative microneedle 14 are adjacent to each other and are arranged so that their tips protrude on the same side, allowing the entire device to be configured compactly and miniaturized. Furthermore, the positive microneedle 13 and the negative microneedle 14 can be easily pierced or pressed against a target object simultaneously, making the device easy to handle.

[0039] The positive microneedle 13 and the negative microneedle 14 of the fluid injection device 10 were manufactured, and various tests were performed on the fluid injection device 10. The reagents and materials used in the manufacturing and testing were as follows.

[0040] - Glycidyl methacrylate (GMA, Fujifilm Wako Pure Chemical Industries, Ltd.) - Trimethylolpropane trimethacrylate (TRIM, Sigma-Aldrich Corporation) - Polyethylene glycol (PEG 10 kDa, Sigma-Aldrich Corporation) - Diethylene glycol (DEG, Tokyo Chemical Industry Co., Ltd.) - Irgacure 184 (BASF SE) - Polydimethylsiloxane (PDMS, SILPOT 184, DuPont-Toray Specialty Materials Co., Ltd.) - Gellan gum (Fujifilm Wako Pure Chemical Industries, Ltd.) - Triethylene glycol dimethacrylate (TEGDMA) - (3-acrylamidopropyl) trimethylammonium (APTA)・2-acrylamide-2-methylpropanesulfonic acid (AMPS) ・2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA-044) ・N,N'-methylenebisacrylamide (MBAAmM) ・N,N,N',N'-tetramethylethylenediamine (TEMED) ・ammonium peroxodisulfate solution (APS, 10 w / v%) ・Fluorescein isothiocyanate-dextran (FITC-dextran, average mol wt 500.Fluorescein isothiocyanate-ovalbumin (FITC-OVA, 4.4 kDa, 0.75 mg / mL, Sigma-Aldrich) and 1xPBS(-) (phosphate-buffered saline, Fujifilm Wako Pure Chemical Industries, Ltd.).

[0041] [Fabrication of Microneedle Arrays] Arrays of positive microneedles 13 and negative microneedles 14 were fabricated. First, holes were drilled into an acrylic plate using a cutting machine to create a female mold for each microneedle protrusion. This female mold was then transferred in two steps using PDMS to create a PDMS female mold. Then, precursor solutions for forming the porous body were prepared. The precursor solutions were prepared by mixing a photopolymerization initiator with Solution A and Solution B, each of which had the following composition: Solution A was prepared by mixing PEG (4 g), which can form pores in the structure when dissolved, with DEG (20 mL) as a solvent at 60°C. Solution B was prepared by mixing GMA (10 mL), a monomer, with Trim (5.23 mL) and TEGDMA (15.7 mL), a crosslinking agent.

[0042] Next, solution A (450 μL), solution B (550 μL), and the photopolymerization initiator Irgacure 184 (1.8 mg) were mixed at 40°C to obtain a precursor solution. The precursor solution was poured into a PDMS female mold and degassed for 80 minutes at 25°C and a reduced pressure of -0.096 MPa. This degassing process prevents damage to the needle shape due to air bubbles. After degassing, the substrate was irradiated with 365 nm UV light at 25°C for 1 hour to polymerize the monomer and crosslinker. The solidified protrusion array substrate was then removed from the female mold. The protrusion array substrate was then immersed overnight in a mixture of distilled water and methanol (volume ratio 1:1) to elute the PEG. This resulted in the production of the microneedle array shown in Figure 2, which has a porous structure.

[0043] Next, the fabricated porous microneedle array was immersed in a silane coupling agent solution (2 mL; TMSPMA 0.6 mL, ethanol 1.4 mL) at room temperature for 1 hour to modify the surface, including the interior of the pores, with the silane coupling agent. The modified substrate was then rinsed twice, 15 minutes each, in distilled water while shaking on a shaker to remove excess unreacted TMSPMA and ethanol. After thoroughly wiping to remove water, the substrate was immersed in the following solution (1) for fixing negative charges, or the following solution (2) for fixing positive charges, at 4°C for 8 hours: (1) 0.05 M AMPS, 1 v% APS, and 0.1 v% TEMED; or (2) 0.4 M APTAC with 2 v% VA-044.

[0044] After immersion in each solution, AMPS or PAPTAC was graft-polymerized onto the pore walls of the microneedle array by polymerization in an oven at 80°C for 1 hour, thereby producing an array of negative-side microneedles 14 with a fixed negative charge and an array of positive-side microneedles 13 with a fixed positive charge.

[0045] [Electroosmotic Flow Generation Test] An electroosmotic flow generation test was conducted using the fabricated array of positive microneedles 13 and negative microneedles 14. First, the test was conducted using a Franz cell with horizontal capillaries as shown in Figure 3(a). In the test, the positive microneedles 13 or negative microneedles 14 were sandwiched between the two chambers 31 of the Franz cell and fixed with a jig made of acrylic plates. Both chambers 31 (opening diameter 15 mm) of the Franz cell were filled with PBS buffer solution at pH 7.0, and the inlet of each chamber 31 was closed and sealed with a silicone rubber stopper 33 pierced with an Ag / Cl wire 32.

[0046] In this state, the Ag / Cl wire 32 (AgCl + e- ⇔ Ag + Cl-) was connected to the source meter 34, and measurements were made of -1.0, -0.5, -0.25, 0, 0.25, 0.5, and 1.0 mA / cm 2A direct current of 1.6 mm was applied for 15 minutes each, and the time-dependent change in the water surface position in the horizontal capillary 35 (cross-sectional diameter 1.6 mm) was measured every 5 minutes using a camera. During the test, it was confirmed that no bubbles were generated from the Ag / Cl wire 32 due to the electrode reaction.

[0047] The test results are shown in Figure 3(b). As shown in Figure 3(b), it was confirmed that electroosmotic flow occurs in both the positive microneedle 13 ("positive charge fixed" in the figure) and the negative microneedle 14 ("negative charge fixed" in the figure), and the flow rate increases as the current density increases. It was also confirmed that the flow direction is opposite for the positive microneedle 13 and the negative microneedle 14, and the slopes of the graphs (electroosmotic flow efficiency) are approximately the same.

[0048] Next, a test was conducted using the Franz cell shown in Figure 4(a) by placing a mixture of FITC-OVA and PBS buffer solution in both chambers 31 to measure the amount of molecular transport due to electroosmotic flow. In the test, a current of -0.5 mA / cm was measured between each cell from the source meter 34. 2 (for the positive microneedle 13) or 0.5 mA / cm 2 A direct current (in the case of the negative microneedle 14) was applied, and every 30 minutes, a small amount of the solution in the receptor-side chamber 31 (chamber 31 on the left side of the figure) was sampled and quantitatively analyzed using a plate reader to measure the amount of molecules transported from the donor-side chamber 31 (chamber 31 on the right side of the figure) to the receptor-side chamber 31.

[0049] The test results are shown in Fig. 4(b). As shown in Fig. 4(b), the positive microneedle 13 ("-0.5 mA / cm" in the figure) 2 ") and the negative microneedle 14 ("0.5 mA / cm 2") and it was confirmed that electroosmotic flow occurred, and the amount of FITC-OVA molecular transport (Transported OVA) increased over time. It was also confirmed that approximately the same amount of transport occurred in opposite directions between the positive-side microneedle 13 and the negative-side microneedle 14. Measurements were also performed when no current was applied ("0 mA / cm" in the figure). 2 ") and confirmed that no transportation would occur.

[0050] Next, as shown in Figure 5(a), a test was conducted to inject dextran into a pig skin section 36 using the fluid injection device 10 shown in Figure 1, which used the manufactured positive microneedle 13 and negative microneedle 14. In the test, FITC dextran was used as the first fluid 21 and the second fluid 22, and a current of -0.5 mA / cm was injected into the positive microneedle 13. 2 and 0.5 mA / cm to the negative microneedle 14. 2 The state of penetration of FITC dextran into the inside of the pig skin section 36 when each of the applied voltages was observed using a fluorescence microscope.

[0051] The test results are shown in Figures 5(b) to 5(e). As shown in Figures 5(b) to 5(e), both when a current was applied to the positive microneedle 13 and when a current was applied to the negative microneedle 14, fluorescence was observed inside the pig skin slice 36, confirming that FITC dextran had penetrated.

[0052] 1 using the manufactured positive microneedles 13 and negative microneedles 14, a test was conducted to inject dextran into the glangum gel 37. In the test, agarose gel containing FITC dextran was used as the first fluid 21 and the second fluid 22, and the positive microneedles 13 and negative microneedles 14 were pierced into the glangum gel 37, and electricity was applied with the negative microneedle 14 side serving as the positive electrode (anode) and the positive microneedle 13 side serving as the negative electrode (cathode).

[0053] The test results are shown in Figures 6(a) to 6(c). As shown in Figure 6(b), when the sample was left for 20 minutes without current (0 mA), no fluorescence was observed in the glangum gel 37, confirming that FITC-dextran had not penetrated. In contrast, as shown in Figure 6(c), when a current of 2.5 mA was applied for 20 minutes, fluorescence was observed in the glangum gel 37, confirming that FITC-dextran had penetrated from both electrodes.

[0054] [Example of Fluid Injection Device: Stamp-Type Device] As shown in Figure 7, the fluid injection device 10 has a rigid tubular body 41 that integrally forms the first transport body 11 and the second transport body 12. The tubular body 41 is elongated and has two hollow portions 42a, 42b extending from one end to the other inside, and one hollow portion 42a may form a first transport flow path, and the other hollow portion 42b may form a second transport flow path.

[0055] 7, the fluid injection device 10 has a structure in which a semicircular positive microneedle 13 and a semicircular negative microneedle 14 are fitted into one end of a tube 41 so that the first flow path of the positive microneedle 13 communicates with the first transport flow path and the second flow path of the negative microneedle 14 communicates with the second transport flow path. The tube 41 is made of resin and is manufactured using a 3D printer.

[0056] As shown in Figure 7(c), the fluid injection device 10 is used by holding the tubular body 41 in one hand and pressing one end of the tubular body 41 against a target object. This allows the positive microneedle 13 and the negative microneedle 14 to be pierced or pressed against the target object, making the fluid injection device 10 easy to handle. The fluid injection device 10 can be used, for example, on the body surface or scalp, as well as on organs or tumors exposed by abdominal incision. Furthermore, because the fluid injection device 10 is integrally provided by the tubular body, the entire device can be configured compactly, allowing for miniaturization.

[0057] A fluid injection test was conducted using the fluid injection device 10 shown in FIG. 7 . In the test, a solution of rhodamine B (0.75 mg / mL, 479 Da) was used as the first fluid 21 on the positive microneedle 13 side, and a solution of methylene blue (0.75 mg / mL, 320 Da) was used as the second fluid 22 on the negative microneedle 14 side. As shown in FIG. 8( a), the positive microneedle 13 and the negative microneedle 14 were pierced into the glungum gel 38, and a current of 2.0 mA was applied between the first electrode 24 and the second electrode 25 for 20 minutes. The results are shown in FIG. 8 . As shown in FIG. 8( b), it was confirmed that approximately equal amounts of rhodamine B and methylene blue had permeated the glungum gel 38 from both the positive microneedle 13 and the negative microneedle 14, respectively.

[0058] Next, a vaccine model (OVA) was inoculated into mice using the fluid injection device 10 shown in FIG. 7 . In the test, the positive microneedle 13 and the negative microneedle 14 were immersed in a PBS buffer solution or a 10 mg / mL OVA aqueous solution for two hours. That is, three combinations of the positive microneedle 13 and the negative microneedle 14 were tested: PBS and PBS, OVA and PBS, and OVA and OVA. In the test, a PBS aqueous solution was used as both the first fluid 21 on the positive microneedle 13 side and the second fluid 22 on the negative microneedle 14 side.

[0059] The test was carried out as follows: First, as shown in Fig. 9(a), the positive microneedle 13 and the negative microneedle 14 of the fluid injection device 10 were pressed against the back of a hairless mouse 51, and a current of 0.5 mA / cm was applied between the first electrode 24 and the second electrode 25. 2A current density of 100 μL was applied for 1 minute. Seven days later, a second current was applied under the same conditions. After another 7 days (14 days after the initial current application), mouse 51 was euthanized, and the blood was centrifuged to collect serum. The serum was analyzed for IgG antibody levels. To measure antibody titers, a 96-well plate was coated with 10 μg / mL OVA overnight at 4°C and then blocked with 3% BSA. 100 μL of serum diluted with 1% BSA was added and incubated for 2 hours. Biotin-labeled anti-mouse IgG antibody was then added and incubated for another 2 hours. The absorbance at 450 nm was then measured using a microplate reader. The measured absorbance is proportional to the amount of IgG antibody in the serum.

[0060] The measurement results are shown in Figure 9(b). Measurements were performed four times under each condition, and the error bars in the figure indicate standard deviations. Compared to when both the positive microneedle 13 and the negative microneedle 14 were PBS, when one was OVA, a larger absorbance (optical density) was observed, confirming a higher amount of IgG antibody in the serum. Furthermore, when both were OVA, the amount of IgG antibody produced was even greater. For comparison, measurements were also performed when both were OVA and no current was applied ("No Current" in the figure), confirming that almost no IgG antibody was produced. These results confirmed that OVA administration was achieved by electroosmotic flow caused by current application.

[0061] [Example of Fluid Injection Device: Catheter-Type Device] As shown in Fig. 10(a), in a fluid injection device 10, the first transporter 11 and the second transporter 12 each comprise a flexible tube 43 such as a catheter, and may be connected to each other on their outer surfaces along the length. In the example shown in Fig. 10(a), the positive microneedle 13 and the negative microneedle 14 each comprise one microneedle. More specifically, the first transporter 11 and the second transporter 12 each comprise a silicone tube with an outer diameter of 2 mm.

[0062] As shown in FIG. 10(b), the fluid injection device 10 shown in FIG. 10(a) can easily access tissue inside a living body 1 and directly inject drugs and the like into the tissue. This allows, for example, anticancer drugs to be administered directly to tumors, resulting in effective treatment. For example, in Non-Patent Document 2, which demonstrated the effectiveness of iontophoresis on tumors, drug penetration from the positive electrode was utilized, with the negative electrode located far away, resulting in a design that allowed unnecessary current to flow throughout the body. In contrast, as shown in FIG. 10(b), the fluid injection device 10 shown in FIG. 10(a) can be inserted into the body of a living body 1 through a minimal incision using a catheter system, allowing drugs to be administered directly to tumors from both the positive and negative electrodes without causing unnecessary current to flow throughout the body.

[0063] REFERENCE SIGNS LIST 10 Fluid injection device 11 First transporter 21 First fluid 12 Second transporter 22 Second fluid 13 Positive microneedle 14 Negative microneedle 23 Flange portion 15 Current / voltage application means 24 First electrode 25 Second electrode 31 Chamber 32 Ag / Cl wire 33 Silicone rubber stopper 34 Source meter 35 Horizontal capillary 36 Pig skin slice 37, 38 Glan gum gel 41 Tubular body 42a, 42b Hollow portion 43 Tube 51 Mouse

Claims

1. A first transporter having a first transport flow path for allowing a first fluid to flow; a second transporter having a second transport flow path for allowing a second fluid to flow; a positive microneedle provided on the first transporter having a first opening at a tip portion and a first flow path in which a positive charge is fixed and which communicates with the first opening, the positive microneedle provided on the first transporter such that the first flow path communicates with the first transport flow path; a negative microneedle provided on the second transporter having a second opening at a tip portion and a second flow path in which a negative charge is fixed and which communicates with the second opening, the negative microneedle provided on the second transporter such that the second flow path communicates with the second transport flow path; a first electrode disposed on the first transport flow path and a second electrode disposed on the second transport flow path, and a current / voltage application means provided so as to be able to apply a current or voltage between the first electrode and the second electrode; a fluid injection device configured such that, when a current or voltage is applied between the first electrode and the second electrode by the current / voltage application means, an ionic current flows through the first fluid in the first flow path and the second fluid in the second flow path, and the first fluid flows outward from the first opening and the second fluid flows outward from the second opening due to electroosmotic flow.

2. A fluid injection device according to claim 1, characterized in that the positive microneedle and the negative microneedle are arranged adjacent to each other.

3. A fluid injection device as described in claim 1, characterized in that: the first transporter is elongated and the first transport flow path extends from one end to the other end; the second transporter is elongated and the second transport flow path extends from one end to the other end; the positive side microneedle is provided at the one end of the first transporter; and the negative side microneedle is provided at the one end of the second transporter.

4. A fluid injection device as described in claim 3, characterized in that the positive side microneedle is arranged so that its tip protrudes from the one end of the first transporter along the extension direction of the first transporter, and the negative side microneedle is arranged so that its tip protrudes from the one end of the second transporter along the extension direction of the second transporter.

5. The fluid injection device according to claim 1, wherein said first transport body and said second transport body are integrally provided.

6. A fluid injection device as claimed in any one of claims 1 to 4, characterized in that it has a rigid tubular body which integrally constitutes the first transport body and the second transport body, the tubular body being elongated and having two hollow portions extending therein from one end to the other, one of the hollow portions forming the first transport flow path and the other hollow portion forming the second transport flow path.

7. A fluid injection device according to any one of claims 1 to 5, characterized in that the first transport body and the second transport body each comprise a flexible tube.

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