Plasma nanomist generator

Abstract

This plasma nano mist generation device comprises: a discharge tube into which a solution is injected, the discharge tube being configured from a dielectric; a liquid-feeding unit for feeding the solution into the discharge tube; an electrode provided within the discharge tube; a voltage application unit for applying a voltage to the electrode; a grounding electrode provided on the distal-end side of the electrode and on the outer periphery of the discharge tube, the grounding electrode being grounded within the device itself; and a control unit for controlling the liquid-feeding unit and the voltage application unit so as to feed the solution into the discharge tube and apply a voltage to the electrode such that dielectric barrier discharge occurs on the distal-end side of the electrode to generate a plasma nano mist.

Description

[Technical field]

[0001] The present disclosure relates to a plasma nano-mist generating device. [Background technology]

[0002] Atmospheric pressure plasma is a key technology behind many industrial innovations, as it generates electric fields, optical radiation, heat, and reactive chemical species. In recent years, plasma systems have been explored for applications in medicine and biology as an effective tool for wound healing (see, for example, WO 2011 / 071182) and cancer treatment (see, for example, "Nagatsu Masaaki, Yang Enbo, Zhang Rilhan, Sakudo Shoichi, Ikuta Kazuyoshi, Bio-medical applications of plasma-modified nanoparticles," Hyomen Kagaku, Vol. 34, No. 10, pp. 535-540, 2013.").

[0003] These biomedical applications are mainly based on applying plasma-derived physical and chemical stimuli (such as ultraviolet light and reactive oxygen and nitrogen species) directly to the target object. This is fine when the affected area is exposed, such as a wound, but applying plasma directly to a lesion inside the body places a significant surgical burden on the patient.

[0004] On the other hand, there has been little research into biomedical technologies that indirectly utilize the effects of plasma. For example, if we could use plasma to manipulate the morphology of drugs and drug solutions and promote their percutaneous absorption, this could lead to new developments in medical technology that reduces the burden on the entire body.

[0005] Nanoparticleization is important to promote transdermal absorption of drugs. Nanotechnology-based delivery systems allow drugs to pass through the skin barrier, reach the target site in a stable state, and maintain their effectiveness for a long period of time. Plasma-generated nanoparticles (see, for example, "Nagatsu, M., Yang, E., Zhang, R., Sakudo, S., Ikuta, K., Bio-medical applications of plasma-modified nanoparticles, Hyomen Kagaku, Vol. 34, No. 10, pp. 535-540, 2013." and "Michael, P., Lam, YT, Filipe, EC et al. Plasma polymerized nanoparticles effectively deliver dual siRNA and drug therapy in vivo. Sci Rep 10, 12836(2020). https: / / doi.org / 10.1038 / s41598-020-69591-x.") can be used in such delivery systems.

[0006] However, these methods have the disadvantage of requiring complicated chemical processes. If nano-sized particulate aggregates could be directly produced from aqueous or oily solutions containing drugs by simple processes, further development of transdermal drug delivery would be expected.

[0007] Electrostatic spraying is known as a technique for nanoparticleizing a solution (generating a nano-sized mist) using electrical effects (see, for example, International Publication No. 2011 / 071182 and JP 2019-058862 A). In addition, a technique is also known for improving the transdermal absorption effect by generating a mist using an atomizing mechanism such as an ultrasonic vibrator and then performing atmospheric pressure plasma treatment. Summary of the Invention [Problem to be solved by the invention]

[0008] However, the electrostatic spray method requires that the target side be grounded to form a closed circuit and that a high voltage be applied, and has the drawback that the target itself is included in the high voltage system.

[0009] Furthermore, the mist generation method using ultrasonic waves has the disadvantage that it requires an atomization mechanism such as an ultrasonic vibrator.

[0010] An object of the present disclosure is to provide a plasma nano-mist generating device capable of generating nano-sized mist with a simple configuration. [Means for solving the problem]

[0011] The plasma nano mist generating device according to the first aspect comprises a discharge tube made of a dielectric and into which a solution is injected, a liquid delivery unit that delivers the solution into the discharge tube, an electrode provided within the discharge tube, a voltage application unit that applies a voltage to the electrode, a ground electrode that is provided on the tip side of the electrode and on the outer periphery of the discharge tube and is grounded within the device, and a control unit that controls the liquid delivery unit and the voltage application unit so that the solution is delivered to the discharge tube and a voltage is applied to the electrode, so that a dielectric barrier discharge is generated at the tip side of the electrode to generate a plasma nano mist.

[0012] In the plasma nano-mist generating device according to the first aspect, the electrode may be a needle electrode or a cylindrical electrode.

[0013] In the plasma nano-mist generating device according to the first aspect, the electrode may be a needle electrode.

[0014] Moreover, the plasma nano-mist generating device according to the first aspect may be configured to include a blower that blows air into the discharge tube.

[0015] Furthermore, in the plasma nano mist generating device according to the first aspect, the control unit may be configured to control the voltage application unit so that a voltage is applied to the electrode that is set based on a correspondence relationship between the type of the solution, the outer diameter of the discharge tube, the outer diameter of the electrode, and the voltage applied to the electrode, the correspondence relationship being a predetermined correspondence relationship that is a generating condition under which the plasma nano mist can be generated.

[0016] Furthermore, in the plasma nano mist generating device according to the first aspect, the control unit may be configured to control the voltage application unit so that the voltage set based on a correspondence relationship between the type of the solution, the outer diameter of the discharge tube, the outer diameter of the electrode, the voltage applied to the electrode, and a liquid delivery speed of the solution, which is a predetermined correspondence relationship that is a generating condition for generating the plasma nano mist, is applied to the electrode, and the control unit may be configured to control the liquid delivery unit so that the solution is delivered at the liquid delivery speed set based on the correspondence relationship. Effect of the Invention

[0017] According to the present disclosure, there is an effect that nano-sized mist can be generated with a simple configuration. [Brief description of the drawings]

[0018] [Figure 1A] FIG. 1 is a diagram illustrating the configuration of a plasma nano-mist generating device. [Figure 1B] FIG. 2 is a diagram showing a streamer as viewed from below the discharge tube. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 13 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 8 mm, and showing the conditions under which plasma nano-mist can be generated. [Diagram 5] FIG. 11 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 8 mm, and showing the preferable conditions among the conditions under which plasma nano-mist can be generated. [Figure 6A] FIG. 2 is a diagram showing nano-mist generated by the plasma nano-mist generating device. [Figure 6B] FIG. 6B is a partially enlarged view of FIG. 6A. [Figure 7]FIG. 13 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 10 mm, and showing the conditions under which plasma nano-mist can be generated. [Figure 8] FIG. 11 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 10 mm, and showing the preferable conditions among the conditions under which plasma nano-mist can be generated. [Figure 9] FIG. 13 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 15 mm, and showing the conditions under which plasma nano-mist can be generated. [Figure 10] FIG. 11 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 15 mm, and showing the preferable conditions among the conditions under which plasma nano-mist can be generated. [Figure 11] FIG. 13 is a diagram showing discharge characteristics for each solution and for each solution sending speed. [Figure 12] FIG. 13 is a graph showing the relationship between the liquid flow rate of ultrapure water and the electrical conductivity. [Figure 13] FIG. 13 is a graph showing the relationship between the liquid delivery speed of phosphate buffered saline and the electrical conductivity. [Figure 14] FIG. 11 is a diagram showing the relationship between the amount of hydrogen peroxide solution generated and the liquid delivery speed. [Figure 15] FIG. 13 is a graph showing the relationship between the amount of nitrite ions generated and the liquid delivery speed. [Figure 16] FIG. 13 is a graph showing the relationship between the amount of nitrate ions generated and the liquid delivery speed. [Figure 17] FIG. 1 is a diagram showing the configuration of a plasma nano-mist generating device equipped with a blowing section. [Figure 18] FIG. 13 is a diagram showing the corresponding relationship between the outer diameter of the discharge tube, the outer diameter of the electrode, and the applied voltage when the solution is ultrapure water and phosphate buffered saline, and showing the conditions under which plasma nano-mist can be generated. [Figure 19] FIG. 13 is a diagram showing the corresponding relationship between the outer diameter of the discharge tube, the outer diameter of the electrode, and the applied voltage when the solution is ultrapure water and phosphate buffered saline, and showing the conditions under which plasma nano-mist can be generated. [Figure 20] FIG. 13 is a diagram showing a gauge conversion table. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an example of an embodiment of the present disclosure will be described with reference to the drawings.

[0020] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a plasma nano-mist generating device. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 13 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 8 mm, and showing the conditions under which plasma nano-mist can be generated. [Diagram 5] FIG. 11 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 8 mm, and showing the preferable conditions among the conditions under which plasma nano-mist can be generated. [Figure 6A] FIG. 2 is a diagram showing nano-mist generated by the plasma nano-mist generating device. [Figure 6B] FIG. 6B is a partially enlarged view of FIG. 6A. [Figure 7] FIG. 13 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 10 mm, and showing the conditions under which plasma nano-mist can be generated. [Figure 8] FIG. 11 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 10 mm, and showing the preferable conditions among the conditions under which plasma nano-mist can be generated. [Figure 9] FIG. 13 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 15 mm, and showing the conditions under which plasma nano-mist can be generated. [Figure 10]FIG. 11 is a diagram showing the relationship between the outer diameter of the electrode, the applied voltage, and the solution sending speed when the outer diameter of the discharge tube is 15 mm, and showing the preferable conditions among the conditions under which plasma nano-mist can be generated. [Figure 11] FIG. 13 is a diagram showing discharge characteristics for each solution and for each solution sending speed. [Figure 12] FIG. 13 is a graph showing the relationship between the liquid flow rate of ultrapure water and the electrical conductivity. [Figure 13] FIG. 13 is a graph showing the relationship between the liquid delivery speed of phosphate buffered saline and electrical conductivity. [Figure 14] FIG. 11 is a diagram showing the relationship between the amount of hydrogen peroxide solution generated and the liquid delivery speed. [Figure 15] FIG. 13 is a graph showing the relationship between the amount of nitrite ions generated and the liquid delivery speed. [Figure 16] FIG. 13 is a graph showing the relationship between the amount of nitrate ions generated and the liquid delivery speed. [Figure 17] FIG. 1 is a diagram showing the configuration of a plasma nano-mist generating device equipped with a blowing section. [Figure 18] FIG. 13 is a diagram showing the corresponding relationship between the outer diameter of the discharge tube, the outer diameter of the electrode, and the applied voltage when the solution is ultrapure water and phosphate buffered saline, and showing the conditions under which plasma nano-mist can be generated. [Figure 19] FIG. 13 is a diagram showing the corresponding relationship between the outer diameter of the discharge tube, the outer diameter of the electrode, and the applied voltage when the solution is ultrapure water and phosphate buffered saline, and showing the conditions under which plasma nano-mist can be generated. [Figure 20] FIG. 13 is a diagram showing a gauge conversion table.

[0021] 2 and 3, the discharge unit 20 includes a discharge tube 21 and an electrode 22. For example, a needle electrode or a cylindrical electrode is used as the electrode 22. The needle electrode is an electrode having an outer diameter (diameter) of, for example, less than 2 mm, and the cylindrical electrode is an electrode having an outer diameter of, for example, 2 mm or more and 5 mm or less. The electrode 22 is inserted into a through hole of a socket 23 made of, for example, PLA resin (polylactic acid) and having a through hole. The socket 23 is fitted into the discharge tube 21, so that the tip side of the electrode 22 is disposed inside the discharge tube 21.

[0022] The discharge tube 21 is made of a dielectric material such as borosilicate glass, etc. The outer periphery of the discharge tube 21 is covered with a polyimide film tape 24.

[0023] The tip side of the electrode 22 and the outer periphery of the discharge tube 21 are covered with a ground electrode 25 made of, for example, Al (aluminum). The ground electrode 25 is grounded within the plasma nano mist generating device 10. In other words, since the ground electrode 25 is grounded within the device itself and forms a closed circuit, there is no need to ground it on the side to which the plasma nano mist is to be supplied, and safety is increased compared to when an electrostatic spray method is used.

[0024] The other end of the electrode 22 is connected to a syringe pump 31 of a liquid delivery section 30, which will be described later. The electrode 22 has a hollow structure, into which a solution is injected from the syringe pump 31.

[0025] The liquid sending section 30 sends the solution into the discharge tube 21. Specifically, the liquid sending section 30 includes a syringe pump 31 that sends the solution, and a drive section 32 that drives the syringe pump 31.

[0026] The voltage application unit 40 applies a voltage to the other end of the electrode 22. The voltage application unit 40 includes a power supply unit 41, a transformer 42, and a high-voltage amplifier 43. The power supply unit 41 supplies an AC voltage of 100 V. The transformer 42 transforms the AC voltage supplied from the power supply unit 41 into a predetermined AC voltage. The high-voltage amplifier 43 amplifies the AC voltage supplied from the transformer 42 to a high voltage of, for example, several kV to tens of kV, and applies it to the other end of the electrode 22. The frequency of the voltage applied to the other end of the electrode 22 is, for example, about 10 kHz.

[0027] The control unit 50 controls the drive unit 32 and the voltage application unit 40 of the solution delivery unit 30 so that the solution is delivered to the discharge tube 21 and a voltage is applied to the other end of the electrode 22, so that a dielectric barrier discharge, more specifically, a corona-like dielectric barrier discharge is generated on the tip side of the electrode 22 to generate a plasma nano-mist. Here, the plasma nano-mist refers to particles produced by plasma with a diameter of less than 1 μm, i.e., nanometer-sized particles.

[0028] The solution injected from the syringe pump 31 into the electrode 22 becomes charged as it passes through the electrode 22, and generates nanomist by interacting with the plasma generated at the tip of the electrode 22. Note that any liquid delivery means other than a syringe pump may be used as long as it can deliver the liquid at a desired speed. For example, a piezo micropump or the like may be used to deliver the liquid continuously.

[0029] The principle of nanomist generation will be explained below. Streamers ST are generated from the tip of the electrode 22 toward the ground electrode 25 as shown in Figures 1A and 1B. When a high AC voltage is applied to the electrode 22, the discharge tube 21, which is a dielectric in front of the electrode 22, and the layer of air between the electrode 22 and the discharge tube 21 are charged, and an inverse electric field is formed between the tip of the electrode 22, where the charge is locally large, and the surface of the discharge tube 21 located closest to the tip of the electrode 22. As a result, the streamers ST generated by the high electric field are limited, and a discharge space without sparks is obtained.

[0030] The streamer ST is a strongly ionized discharge path when a discharge in air starts. When electrodes are placed in the air and the voltage exceeds a certain value, electrons obtain energy from the electric field and move toward the anode, forming an electron avalanche in the process. Positive ions with large masses generated by ionization are left behind by the electron avalanche, and a strong electric field is generated by the space charge at the anode side, which is the head of the electron avalanche, and the ionized electrons are attracted by the light emitted from the electron avalanche. The inside of the streamer ST is a plasma, and at its tip, a cloud of positive ions moves at high speed toward the other electrode. In addition, a strong light is emitted from the tip of the positive ion cloud, and a photoionized region is formed near the streamer ST. Since the streamer ST is unstable in discharge forms such as spark discharge, it is stabilized by the dielectric barrier discharge described above.

[0031] In addition, when the liquid is sent through the electrode 22, it is charged by a high voltage and is atomized by so-called Coulomb repulsion at the tip of the electrode 22. When the atomized droplets come into contact with the streamer ST, which is a strongly ionized discharge path, further ionization occurs, and the droplets are highly fined to become a nanomist.

[0032] Since the plasma nano-mist generating device 10 has the above-mentioned configuration, it does not require an atomization mechanism such as an ultrasonic vibrator, and can generate plasma nano-mist with a simple configuration.

[0033] Whether or not plasma nano-mist can be generated depends on the type of solution, the outer diameter of the discharge tube 21, the outer diameter of the electrode 22, the voltage applied to the electrode 22, and the solution transfer speed.

[0034] Therefore, the control unit 50 controls the voltage application unit 40 so that a voltage set based on table data representing the correspondence between the type of solution, the outer diameter of the discharge tube 21, the outer diameter of the electrode 22, the voltage applied to the electrode 22, and the solution delivery speed, which is a correspondence relationship that is predetermined as a generation enabling condition for generating the plasma nano mist, is applied to the electrode 22, and controls the drive unit 32 of the liquid delivery unit 30 so that the solution is delivered at the liquid delivery speed set based on the table data. This generates the plasma nano mist. The generated plasma nano mist can be used in a wide range of applications, such as medical and cosmetic products. In addition, the generated plasma nano mist is charged, which improves wettability.

[0035] 4 shows the relationship between the voltage (kV) applied to electrode 22, the solution feed rate (μL / min), and the outer diameter (diameter, mm) of electrode 22 when the outer diameter (diameter, mm) of discharge tube 21 is 8 mm. The solution is ultrapure water (UPW), and the solution is also ultrapure water in Figs. 5 to 10 described later.

[0036] As shown in FIG. 4, assuming that the applied voltage is P (kV), the solution feed rate (μL / min) is S, and the outer diameter (mm) of electrode 22 is D, plasma nano-mist can be generated by satisfying the conditions below, preferably all of the following formulas (1) to (3).

[0037] 7≦P≦17.5 (1) 0 <S<500 ···(2) 0.25≦D≦5 (3)

[0038] Figure 5 shows the optimal conditions among the conditions for generating the plasma nano-mist shown in Figure 4. Here, the optimal conditions refer to conditions under which the phenomenon of droplets (droplets) being generated from the discharge tube 21 does not occur. As shown in Figure 5, the range of optimal conditions is narrower than the range of conditions for generating the plasma nano-mist shown in Figure 4.

[0039] 6A and 6B are images of mist generated by the plasma nanomist generator 10 using ultrapure water as a solution, taken with a digital camera using a 10x microscope lens at an ISO sensitivity of 8000 and a shutter speed of 1 / 8000 seconds. FIG. 6A is an image of the generated mist, and FIG. 6B is an enlarged view of a portion of the area surrounded by a white frame in FIG. 6A. From FIG. 6B, it can be confirmed that the generated mist is equal to or smaller than the minimum pixel size (2150 nm x 2150 nm) of the camera that took the image, and that the generated mist is in the range of micro to nano sizes of 2.15 μm or less.

[0040] FIG. 7 shows the correspondence between the voltage (kV) applied to electrode 22, the solution feed rate (μL / min), and the outer diameter (diameter, mm) of electrode 22 when the outer diameter (diameter, mm) of discharge tube 21 is 10 mm.

[0041] As shown in FIG. 7, the range of conditions under which plasma nano-mist can be generated is narrower than when the outer diameter (diameter, mm) of the discharge tube 21 in FIG. 4 is 8 mm.

[0042] Fig. 8 shows the preferable conditions among the conditions under which the plasma nano-mist can be generated shown in Fig. 7. As shown in Fig. 8, the range of the preferable conditions is narrower than the range of conditions under which the plasma nano-mist can be generated shown in Fig. 7.

[0043] FIG. 9 shows the correspondence between the voltage (kV) applied to electrode 22, the solution feed rate (μL / min), and the outer diameter (diameter, mm) of electrode 22 when the outer diameter (diameter, mm) of discharge tube 21 is 15 mm.

[0044] As shown in Figure 9, the range of conditions under which plasma nano-mist can be generated is narrower than when the outer diameter (diameter, mm) of the discharge tube 21 in Figure 4 is 8 mm and when the outer diameter (diameter, mm) of the discharge tube 21 in Figure 7 is 10 mm.

[0045] Fig. 10 shows the preferable conditions among the conditions under which the plasma nano-mist can be generated shown in Fig. 9. As shown in Fig. 10, the range of the preferable conditions is narrower than the range of conditions under which the plasma nano-mist can be generated shown in Fig. 9.

[0046] Furthermore, whether or not a solution tends to turn into mist depends on the conductivity of the solution. That is, the higher the conductivity of the solution, the more likely it is to turn into mist, and the lower the conductivity, the less likely it is to turn into mist.

[0047] FIG. 11 shows the results of measuring the voltage and current applied to electrode 22, i.e., the results of measuring the discharge characteristics, for three types of solutions: ultrapure water (UPW), phosphate buffered saline (PBS), and castor oil (CO), with the solution delivery speed changed to 10 (μL / min), 50 (μL / min), and 100 (μL / min). As shown in FIG. 11, the discharge characteristics differ depending on the solution. And, the difference in the discharge characteristics of the solutions means that the conductivity of the solutions is different, and therefore the likelihood of becoming mist differs.

[0048] FIG. 12 shows the results of measuring the conductivity of ultrapure water when the ultrapure water flow rate was changed to 50 (μL / min), 100 (μL / min), and 1000 (μL / min).

[0049] In addition, Figure 13 shows the results of measuring the conductivity of phosphate buffered saline when the liquid delivery speed was changed to 50 (μL / min), 100 (μL / min), and 1000 (μL / min). As shown in Figures 12 and 13, the conductivity differs depending on the type of solution. In other words, the tendency to become mist differs.

[0050] Therefore, by controlling the voltage applied to the electrode 22 and the speed at which the solution is sent depending on the type of solution, it is possible to appropriately turn the solution into a nano-mist.

[0051] In addition, the interaction between the plasma generated at the tip of the electrode 22 and the solution produces, for example, hydrogen peroxide (H2O2), nitrite ions (NO2 - ), and nitrate ion (NO3 -) may produce reactive chemical species that have disinfecting or germicidal effects.

[0052] FIG. 14 shows the results of measuring the amount of hydrogen peroxide solution (mg / L) dissolved in ultrapure water (UPW) by changing the solution delivery speed (μL / min) when the solution was ultrapure water.

[0053] FIG. 15 shows the results of measuring the amount of nitrite ions (mg / L) dissolved in ultrapure water (UPW) by changing the solution delivery speed (μL / min) when the solution was ultrapure water.

[0054] FIG. 16 shows the results of measuring the amount of nitrate ions (mg / L) dissolved in ultrapure water (UPW) by changing the solution delivery speed (μL / min) when the solution was ultrapure water.

[0055] 14 to 16, it can be seen that the amount of reactive chemical species varies depending on the type of reactive chemical species. When it is desired to suppress the generation of reactive chemical species, a scavenger may be mixed into the solution.

[0056] 17, a configuration may be provided in which a blower 60 is provided to blow air into the discharge tube 21. This makes it easier to send the generated plasma nano-mist to the outside of the discharge tube 21.

[0057] In addition, although the discharge tube 21 is set facing downward in FIG. 1A, it is also possible to install the discharge tube 21 facing upward or sideways.

[0058] Furthermore, when it is desired to generate a large amount of nano-mist, a bundle of a plurality of discharge tubes 21 and electrodes 22 can be used.

[0059] 17, in the case of a configuration in which air is blown into the discharge tube 21 and in the case of the configuration shown in Fig. 1A with the discharge tube 21 facing upward, the solution sending speed does not affect the generation of droplets. In this case, the control unit 50 controls the voltage application unit 40 so that a voltage set based on table data representing correspondence relationships among the type of solution, the outer diameter of the discharge tube 21, the outer diameter of the electrode 22, and the voltage applied to the electrode 22 is applied to the electrode 22.

[0060] FIG. 18 shows the relationship between the outer diameter (mm) of the discharge tube 21, the outer diameter (G) of the electrode 22, and the applied voltage (kV) in ultrapure water and phosphate buffered saline as conditions for generating plasma nano-mist.

[0061] Fig. 19 shows the relationship between the outer diameter (mm) of the discharge tube 21, the outer diameter (G) of the electrode 22, and the applied voltage (kV) in castor oil. Fig. 20 shows a gauge conversion table showing the relationship between the gauge (G), outer diameter (mm), inner diameter (mm), and wall thickness (mm).

[0062] 18 and 19, the white areas are areas where plasma nano mist is not generated, and the other areas are areas where the conditions are such that plasma nano mist can be generated. Also, because discharge tube 21 will be damaged if a voltage higher than 17.5 kV is applied, the applied voltage must be 17.5 kV or less. As shown in Figures 18 and 19, it can be seen that the conditions for generating plasma nano mist differ when the solution is ultrapure water and phosphate buffered saline, and when the solution is castor oil.

[0063] Although the embodiment of the present disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present disclosure are also included.

[0064] For example, the solution is not limited to ultrapure water, castor oil, and phosphate buffered saline, but may be, for example, methanol, ethanol, 1-propanol, 2-propanol, butanol, fragrance (including both oil-based and water-based), pigment-based ink, and dye-based ink. Specific examples of fragrance include essential oils and volatile oil-based fragrances, and the components include fragrances dissolved in alcohol, carbon disulfide, petroleum ether, and fatty oil. For pigment-based ink and dye-based ink, inks using, for example, vegetable oil derivatives as the main component can be used. For pigment-based ink, it is possible to turn pigment-based ink dissolved in, for example, an organic solvent into nano-mist without any problem.

[0065] The disclosure of Japanese Patent Application No. 2022-057334 is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. a discharge tube made of a dielectric material and into which a solution is injected; A liquid delivery unit that delivers the solution into the discharge tube; an electrode provided in the discharge tube and capable of delivering the solution; A voltage application unit that applies a voltage to the electrodes; a ground electrode provided on the tip side of the electrode and on the outer periphery of the discharge tube, the ground electrode being grounded within the device itself; A control unit that controls the solution delivery unit and the voltage application unit so that the solution is delivered to the discharge tube and a voltage is applied to the electrode so that a dielectric barrier discharge is generated at the tip side of the electrode to generate a plasma nanomist; A plasma nanomist generating device equipped with the device.

2. The electrode is a needle electrode or a cylindrical electrode. The plasma nano-mist generating device according to claim 1.

3. The electrode is a needle electrode. The plasma nano-mist generating device according to claim 2.

4. A blower for blowing air into the discharge tube The plasma nano-mist generating device according to claim 1 .

5. The control unit controls the voltage application unit so that a voltage set based on a correspondence relationship between the type of the solution, the outer diameter of the discharge tube, the outer diameter of the electrode, and a voltage applied to the electrode is applied to the electrode, the correspondence relationship being a predetermined correspondence relationship as a generation enabling condition for generating the plasma nano mist. The plasma nano-mist generating device according to claim 1.

6. The control unit controls the voltage application unit so that the voltage set based on a correspondence relationship between the type of the solution, the outer diameter of the discharge tube, the outer diameter of the electrode, the voltage applied to the electrode, and a liquid delivery speed of the solution, which is a correspondence relationship previously determined as a generating condition for generating the plasma nano mist, and controls the liquid delivery unit so that the solution is delivered at the liquid delivery speed set based on the correspondence relationship. The plasma nano-mist generating device according to claim 1.

7. The liquid delivery rate is greater than 0 μL / min and less than 500 μL / min. The plasma nano-mist generating device according to claim 6.

8. The solution is any one of ultrapure water, castor oil, and phosphate buffered saline; The outer diameter of the discharge tube is 8 mm or more and 15 mm or less, The outer diameter of the electrode is 0.25 mm or more and 5 mm or less, The voltage is equal to or greater than 7 kV and equal to or less than 17.5 kV. The plasma nano-mist generating device according to any one of claims 1 to 7.

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