Preparation method of plasma activated water based on micro-nano bubble synergistic effect

Abstract

The invention discloses a preparation method of plasma activated water based on a micro-nano bubble synergistic effect, and mainly solves the technical problems that the generation efficiency of liquid-phase active particles in the plasma activated water prepared by the existing method is low, the chemical activity of the plasma activated water is difficult to maintain and the like. The preparation method comprises the following steps: introducing micro-nano bubbles into pure water until the pure water is saturated to obtain micro-nano bubble water; then performing plasma activation treatment on the micro-nano bubble water within 3 minutes to obtain plasma activated water based on the micro-nano bubble synergistic effect; the gas adopted by the micro-nano bubbles is one of air, oxygen, nitrogen or helium. The chemical activity of the plasma activated water is enhanced, the maintenance time of the activity of the activated water is greatly prolonged, efficient production and long-acting storage of the plasma activated water are facilitated, and the method has great significance in biomedical application of the plasma activated water.

Description

Technical Field

[0001] This invention relates to a method for preparing plasma-activated water, specifically a method for enhancing the chemical activity of plasma-activated water and extending its storage period through the synergistic effect of micro- and nano-bubbles. Background Technology

[0002] Plasma-activated water (i.e., atmospheric pressure cold plasma-activated water) is an aqueous solution with weak acidity and strong oxidizing properties obtained by treating deionized water with atmospheric pressure cold plasma. Atmospheric pressure cold plasma (hereinafter referred to as plasma) generates a large number and variety of gaseous active particles in the gas phase, such as H, O, O3, OH, NO, NO2, N2O, H2O2, and N2O5. When these gaseous active particles come into contact with water, they generate H2O2 and O2 in the liquid phase. - OH, NO, ONOO - Various liquid-phase active particles are used. Due to their strong redox properties, these liquid-phase active particles can participate in a variety of biochemical reactions, making plasma-activated water prepared based on them play a significant role in biomedical applications such as anti-cancer and sterilization.

[0003] However, during the transfer of gaseous active particles from plasma into aqueous solution to form liquid active particles, the strong coupling of mass transfer processes at the gas-liquid interface severely hinders the mass transfer process of the gaseous active particles, resulting in a low concentration of liquid active particles in the water and ultimately weak chemical activity of the plasma-activated water. Simultaneously, the strong chemical reactivity of liquid-phase free radicals causes their extremely short lifespan in aqueous solution. If special cryopreservation treatment is not performed after discharge generation, and the water is simply placed in a normal room temperature environment, the various active particles will rapidly react and consume their respective chemical activities. This makes it difficult to maintain the chemical activity of the prepared plasma-activated water for a long time, and it will significantly weaken with increasing storage time, ultimately losing its application potential in the biomedical field.

[0004] The aforementioned phenomena have greatly affected the application of plasma-activated water. Therefore, how to increase the number of liquid-phase active particles in plasma-activated water to enhance its chemical activity, and how to extend the survival time of active particles in activated water to enhance its storage effect and extend the "shelf life" of its chemical activity are currently the difficult and hot research topics.

[0005] Based on the aforementioned problems, existing technologies primarily maintain the activity of plasma-activated water over extended periods by lowering its temperature. The principle is that cooling inhibits the thermal motion of active particles in the water, thereby reducing the probability of particle collisions and reactions and extending storage time. However, cooling plasma-activated water for storage is time-consuming, and a large number of active particles can still react rapidly during this period, resulting in significant particle consumption. If activated water is prepared directly at low temperatures, the lower temperature further reduces gas-liquid mass transfer efficiency, thus affecting the generation efficiency of liquid-phase active particles. Furthermore, many researchers have attempted to adjust discharge parameters to enhance the chemical activity of plasma-activated water and slow down the decay rate of active particles. However, existing techniques struggle to fundamentally maintain the chemical activity of plasma-activated water, potentially leading to its inability to meet practical application requirements due to the decay of chemical activity, thus limiting its clinical application. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems of low generation efficiency of liquid phase active particles in plasma-activated water prepared by existing methods and difficulty in maintaining the chemical activity of plasma-activated water, and to provide a plasma-activated water preparation method based on the synergistic effect of micro-nano bubbles.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0008] A plasma-activated water preparation method based on the synergistic effect of micro- and nano-bubbles, characterized by the following steps:

[0009] Micro-nano bubbles are passed through pure water until saturation is achieved to obtain micro-nano bubble water; the gas used for the micro-nano bubbles is one of air, oxygen, nitrogen, or helium.

[0010] Plasma activation treatment was performed on micro-nano bubble water within 3 minutes to obtain plasma-activated water based on the synergistic effect of micro-nano bubbles.

[0011] Furthermore, saturation refers to pure water appearing completely opaque and milky white.

[0012] Furthermore, the micro-nano bubbles are generated by introducing gas into a micro-nano bubble machine, with the gas flow rate entering the machine at 180–220 sccm and the introduction time at 1–2 minutes. During this process, the gas flow rate needs to be controlled. If the flow rate is too low, it will draw in ambient air; if the flow rate is too high, it will damage the micro-nano bubble machine. Therefore, the gas flow rate entering the micro-nano bubble machine is controlled at 180–220 sccm. Simultaneously, the gas introduction time also needs to be controlled. If the introduction time is too short, the micro-nano bubble machine will draw in some ambient air, mixing it into the working gas and affecting the purity of the introduced gas. If the introduction time is too long, it can easily lead to excessive pressure inside the micro-nano bubble machine, thus affecting the normal operation of the machine, and a sharp popping sound will accompany the removal of the gas tube. Therefore, controlling the gas introduction time to 1–2 minutes is preferable.

[0013] Furthermore, the plasma activation treatment is performed using one or more plasma jet devices arranged in an array, a coaxial circular tube plasma generator for dielectric barrier discharge, a surface discharge plasma generator, or a sliding arc discharge plasma generator.

[0014] Furthermore, the plasma activation treatment is carried out using an underwater bubble plasma device. This treatment method involves both dielectric barrier discharge and underwater arc discharge during discharge, making it relatively easy to occur and resulting in high efficiency of plasma activation treatment.

[0015] Furthermore, the flow rate of the working gas introduced into the underwater bubble plasma device is 500 sccm to 5000 sccm. Too high or too low a flow rate will affect the efficiency of plasma treatment. The working gas is helium doped with nitrogen, and the ratio of the two is 99:1.

[0016] Furthermore, the flow rate of the working gas is 1000 sccm to 2000 sccm, within which the plasma activation treatment is most effective.

[0017] Furthermore, it also includes the steps of dispensing, sealing, and refrigerating plasma-activated water using centrifuge tubes.

[0018] Furthermore, the low temperature is 0–10°C.

[0019] Furthermore, the low temperature is 4°C.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The present invention provides a plasma-activated water preparation method based on the synergistic effect of micro-nano bubbles, which can improve the generation efficiency and concentration of liquid-phase active particles in plasma-activated water under the synergistic effect of micro-nano bubbles, thereby enhancing its chemical activity.

[0022] 2. The present invention provides a plasma-activated water preparation method based on the synergistic effect of micro-nano bubbles. This method can utilize micro-nano bubbles in plasma-activated water to slow down the decay rate of liquid-phase active particles, thereby extending the effective retention time of chemical activity in plasma-activated water.

[0023] 3. In the plasma-activated water preparation method based on the synergistic effect of micro-nano bubbles in this invention, the gas used for micro-nano bubbles is oxygen. The working gas introduced into the underwater bubble plasma device can be helium-doped nitrogen. Oxygen micro-nano bubbles can dissolve in water through the high internal pressure characteristics of the bubbles themselves, thereby enhancing the oxidizing properties of the resulting plasma-activated water. Nitrogen-doped helium, as the working gas of the underwater bubble plasma device, can enhance the discharge effect through Penning ionization. At the same time, oxygen in the water and nitrogen doped in the gas can undergo a synergistic reaction to generate a large number of peroxynitrite ions in the plasma-activated water to enhance its activity.

[0024] 4. In the plasma-activated water preparation method based on the synergistic effect of micro-nano bubbles in this invention, when the micro-nano bubble water is activated by an underwater bubble plasma device, both dielectric barrier discharge and underwater arc discharge exist, thus the efficiency of plasma activation treatment is high.

[0025] 5. This invention enables the large-scale production of plasma-activated water, which can then be packaged, sealed, and stored; at the same time, the "shelf life" of the chemical activity and biomedical effects of the prepared plasma-activated water is significantly extended.

[0026] 6. The plasma-activated water prepared by this invention can be further slowed down by low-temperature refrigeration to slow down the decay rate of active particles in the plasma-activated water and increase the preservation time of its chemical activity.

[0027] 7. The plasma-activated water preparation method based on the synergistic effect of micro-nano bubbles in this invention is simple and easy to implement, which greatly reduces the cost required for efficient preparation and long-term effective storage of plasma-activated water, and has the characteristics of being economical and efficient. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the underwater bubble plasma device used for plasma activation treatment in an embodiment of the present invention.

[0029] Figure 2The images shown are comparisons of the appearance changes of pure water before and after the introduction of micro-nano bubbles in the embodiments of the present invention, wherein: (a) shows the pure water after the introduction of micro-nano bubbles, and (b) shows the pure water before the introduction of micro-nano bubbles.

[0030] Figure 3 This is a comparison chart showing the changes in hydrogen peroxide concentration in plasma-activated water prepared by micro-nano bubbles with different gaseous raw materials under the same plasma treatment conditions, according to an embodiment of the present invention.

[0031] Figure 4 The figures show a comparison of the physicochemical properties of pure water before and after underwater bubble plasma treatment, and before and after the introduction of micro-nano bubbles in the embodiments of the present invention. (a) The figure shows a comparison of the pH values ​​of different aqueous solutions, and (b) The figure shows a comparison of the ORP values ​​of different solutions.

[0032] Figure 5 This is a comparison chart of the concentrations of major active particles in four different aqueous solutions before and after the introduction of micro / nano bubbles and before and after plasma treatment, according to an embodiment of the present invention. (a) The chart compares the concentrations of H2O2, and (b) the concentrations of NO2... - The concentration comparison chart, (c) shows the concentration of ONOO. - / O2 - Figure (d) shows a comparison of the concentrations of OH.

[0033] Figure 6 The figures shown are curves illustrating the changes in the concentrations of short-lived active particles over storage time in plasma-activated water prepared according to embodiments of the present invention and plasma-activated water without the addition of micro / nano bubbles. Figure (a) shows the changes in the concentrations of short-lived active particles over storage time in ONOO. - / O2 - Figure 1 is a comparison chart of the concentration changes of OH, and Figure 2 is a comparison chart of the concentration changes of OH.

[0034] Figure 7 The following are comparative figures on the anticancer effects and storage time of plasma-activated water prepared in the embodiments of the present invention and other plasma-activated waters: (a) Figure shows the comparison of cell viability when different plasma-activated waters are directly applied to cancer cells, and (b) Figure shows the comparison of cell viability when different plasma-activated waters are left to stand for a period of time before treating cancer cells.

[0035] Figure 8 Images showing a comparison of the number of cancer cells observed under a microscope after treatment with different aqueous solutions. Detailed Implementation

[0036] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] This embodiment provides a plasma-activated water preparation method based on the synergistic effect of micro- and nano-bubbles. The specific preparation method is as follows:

[0038] When micro-nano bubbles are introduced into pure water until saturation, the color of the pure water changes from colorless to white and its transparency gradually decreases. When it approaches saturation or even supersaturation, the pure water becomes completely opaque and milky white. Figure 2 As shown in the figure, micro-nano bubble water is obtained at this time; then, the micro-nano bubble water is immediately subjected to plasma activation treatment to obtain plasma activated water based on the synergistic effect of micro-nano bubbles.

[0039] After introducing a large number of micro- and nano-bubbles to turn pure water milky white, the settling time should be as short as possible. Ideally, plasma treatment should be performed immediately after removal. Although micro- and nano-bubbles are relatively stable in aqueous solutions, experiments have shown that if the settling time is too long, the color will still fade until it becomes colorless and transparent, which will greatly weaken the synergistic effect of micro- and nano-bubbles. Therefore, the obtained micro- and nano-bubble water should be plasma treated immediately (generally within 3 minutes, preferably within 30 seconds) to ensure the presence of a large number of micro- and nano-bubbles and maximize their synergistic effect in the plasma treatment process.

[0040] This embodiment introduces micro- and nano-bubbles into the plasma treatment of pure water. Through the synergistic reaction of these micro- and nano-bubbles, the chemical activity and concentration of active liquid-phase particles in the plasma-activated water are significantly higher than those of ordinary plasma-activated water. The synergistic effect of micro- and nano-bubbles mentioned here emphasizes that when a large number of micro- and nano-bubbles are present in the plasma-activated water, the inherent characteristics of these bubbles enhance the plasma treatment effect and prolong the duration of activity in the plasma-activated water. The synergistic effect of micro- and nano-bubbles in the preparation of plasma-activated water refers to the alteration of their properties after being introduced into pure water. Compared to existing technologies, the activated water obtained in this embodiment, under the same conditions, exhibits stronger chemical activity after plasma treatment.

[0041] In this embodiment, the micro-nano bubbles are generated by introducing gas into a micro-nano bubble generator. The gas flow rate into the generator is 200 sccm, and the introduction time is approximately 1 minute. Regarding the gas feedstock, air, oxygen, nitrogen, helium, etc., can be selected. Rare gas molecules, as monatomic molecules, undergo more elastic collisions during discharge in water, which greatly improves the energy utilization rate of electrons, thus significantly enhancing the discharge. However, their usage cost is relatively high. Introducing oxygen results in the best activation effect for micro-nano bubbles, followed by air, while introducing nitrogen results in the least effective activation. Due to the ease and availability of air, this embodiment uses air as the gas feedstock to generate micro-nano bubbles.

[0042] Plasma activation treatment can be carried out using plasma jet devices, plasma surface discharge devices, plasma dielectric barrier discharge devices, or plasma sliding arc discharge devices, or underwater bubble plasma devices. Regardless of the treatment method used, the plasma treatment process after introducing micro-nano bubbles has a significant synergistic promoting effect.

[0043] Preferably, in this embodiment, an underwater bubble plasma device is selected to perform plasma activation treatment on micro-nano bubble water to improve its gas-liquid mass transfer efficiency. At the same time, the device makes full use of the physicochemical effects of ultraviolet radiation, strong electric field, electrons, and local thermal field that accompany the plasma generation process to maximize the plasma mass transfer efficiency and energy utilization efficiency.

[0044] Figure 1 The diagram illustrates an underwater bubble plasma device and a container filled with pure water to be treated (i.e., micro / nano bubble water). A high-voltage electrode is connected to an iron rod electrode within the underwater bubble plasma device, while a ground electrode is connected to a copper mesh outside the water container. Plasma is generated in the air gap between the glass tube and the iron electrode, and then enters the pure water to be treated in the form of plasma bubbles through small holes in the glass tube. This alters the physicochemical parameters of the aqueous solution and generates a large number of liquid-phase active particles.

[0045] Regarding the working gas introduced into the underwater bubble plasma device, there are several options. While rare gases are easier to discharge, their cost is relatively high; meanwhile, nitrogen and oxygen each have their own advantages and disadvantages in terms of discharge characteristics and the plasma they produce. In this embodiment, air is used as the working gas for discharge, as it is the most economical and efficient way to generate plasma. Furthermore, when treating pure water containing a large number of micro- and nano-bubbles, the generation rate of plasma bubbles needs to be controlled. This process requires avoiding both excessive airflow leading to too many plasma bubbles and incomplete reaction, and insufficient airflow resulting in too few plasma bubbles and unsatisfactory treatment results. Considering all factors, the working gas flow rate is controlled between 500 sccm and 5000 sccm during plasma activation treatment, with an ideal flow rate of 1000 sccm to 2000 sccm.

[0046] In this embodiment, the underwater bubble plasma device is powered by a nanosecond pulse power supply, with air as the working gas. The underwater bubble discharge treatment time is set to 5 minutes, the discharge voltage is set to 10 kV, the air flow rate is set to 1000 sccm, the volume of the pure aqueous solution to be treated is 90 mL, and the ambient temperature during the experimental reaction is room temperature, i.e., 25 °C. In the experiment, the cancer cells treated by plasma-activated water were A549 lung cancer cells.

[0047] The aforementioned underwater bubble plasma generator can be further optimized from a single generator to an array of multiple generators, which facilitates large-scale processing of micro / nano bubble water. The plasma generator can be powered by a high-voltage sinusoidal power supply or a high-voltage pulse power supply, while the pure water in the micro / nano bubble water can be deionized water, ultrapure water, or double-distilled water. The obtained plasma-activated water can be transferred to a storage container for storage and transportation, such as using centrifuge tubes. Other types of storage containers can also be selected, and the storage container can even be connected to a container holding the solution to be treated, automatically flowing into the storage container after generation. Storage and transportation can be further optimized to be carried out in a light-protected or low-temperature environment.

[0048] In this embodiment, air is uniformly chosen as the gas feedstock from the perspectives of economy and universality. Ideally, micro-nano bubbles of oxygen can be introduced into pure water, and then helium-doped nitrogen can be used as the working gas of the underwater discharge device. Under these conditions, the chemical activity and anti-cancer effect of the plasma-activated water produced are optimal.

[0049] The plasma-activated water prepared in this embodiment can achieve long-term storage because it contains a large number of micro- and nano-bubbles. The presence of these micro- and nano-bubbles can reduce the probability of collisions and reactions between short-lived active particles in the liquid phase, thereby extending the lifespan of active particles in the liquid phase of the plasma-activated water and thus achieving long-term effective storage of the plasma-activated water.

[0050] Therefore, the prepared plasma-activated water can be dispensed into centrifuge tubes, then sealed tightly, and stored at a low temperature of 4°C (in a refrigerator) or in an ice-water bath. The combined use of low-temperature refrigeration and micro / nanobubbles can further slow down the decay rate of active particles in the plasma-activated water, increasing its chemical activity retention time. Furthermore, during the storage or transportation of this plasma-activated water containing micro / nanobubbles, the container needs to be sealed and the system kept as stable as possible to reduce bubble decomposition caused by vibration or shaking.

[0051] The micro / nano bubble system introduced in this invention has a significant enhancing effect on the efficient production and long-term storage of plasma-activated water. The reaction mechanism is as follows:

[0052] When the pure water to be treated contains a large number of micro- and nano-bubbles, these micro- and nano-bubbles can synergistically promote plasma treatment of pure water. First, the small size of micro- and nano-bubbles gives them a large specific surface area, which enhances their interaction area with water molecules, thus improving the gas-liquid mass transfer efficiency of active particles in the plasma. Second, the surface charge of micro- and nano-bubbles (i.e., the bubble surface carries a negative charge) affects the arrangement of surrounding water molecules, thereby disrupting the hydrogen bond network between water molecules. The weakening of hydrogen bond strength reduces the surface tension of the aqueous solution, leading to a decrease in the coupling of the gas-liquid interface mass transfer process, which is beneficial to the gas-liquid mass transfer of active particles. Simultaneously, the ultraviolet radiation and local thermal field effects generated during underwater bubble plasma treatment cause the quenching of micro- and nano-bubbles, thereby inducing a large amount of turbulence and eddies in the aqueous solution, disturbing the boundary layer of the aqueous solution and accelerating the diffusion of gaseous active particles into the liquid phase. In conclusion, micro- and nano-bubbles in water can synergistically promote the generation of liquid-phase active particles during plasma treatment from multiple perspectives, including interaction area, interfacial tension, and liquid disturbance.

[0053] Meanwhile, when plasma-activated water contains a large number of micro / nano bubbles, their special properties and slow-release effect can further prolong the decay time of active particles in the liquid phase, thus significantly extending the retention time of the active particles in plasma-activated water. Firstly, the interfacial adsorption effect of micro / nano bubbles causes a large number of active particles to tend to accumulate at the gas-liquid interface, reducing contact with other substances in the liquid phase and thus avoiding rapid reaction consumption. Secondly, the surface charges of a large number of micro / nano bubbles form a double layer, thereby changing the chemical environment of the active particles, making their distribution more uniform, reducing free diffusion, and lowering the possibility of collisions or reactions. Thirdly, the high internal pressure effect inside the micro / nano bubbles can encapsulate some active particles within the bubbles, reducing their contact with the external environment through the physical protection of the bubbles, and the high-pressure environment allows some active particles to exist stably. In summary, the micro / nano bubbles retained after the reaction in plasma-activated water can extend the retention time of active particles in the water through multiple mechanisms such as interfacial adsorption, electrostatic shielding, and high-pressure encapsulation.

[0054] In this embodiment, the synergistic effect of introducing micro / nano bubbles into plasma-treated water is utilized during discharge and settling to efficiently generate plasma-activated water, significantly improving its chemical activity and effective storage period. Based on this, the prepared plasma-activated aqueous solution can be applied in the biomedical field, particularly in anti-cancer applications, where its anti-cancer effects are greatly enhanced and optimized. The method of treating cancer cells by mixing plasma-activated water with a culture medium follows basic methods in this field and will not be elaborated further here.

[0055] The main objective of this invention is to provide a reaction system for treating water using micro-nano bubbles in conjunction with plasma, thereby achieving efficient generation and long-term storage of plasma-activated water. Specific parameters during the reaction process, such as the volume of the solution to be treated, discharge voltage, discharge time, and working gas, can be selected differently according to application needs and actual conditions to meet various biomedical applications.

[0056] Figure 2 The images show photographs taken with a Nikon camera before and after the introduction of micro-nano bubbles into pure water. It can be seen from the images that there is a significant difference in the appearance of the aqueous solution before and after the introduction of micro-nano bubbles: pure water is colorless and transparent (Figure b), while it is milky white after the introduction of micro-nano bubbles (Figure a).

[0057] Figure 3This paper presents a comparison of the activity changes of plasma-activated water prepared by micro / nanobubbles with different gaseous raw materials under the same plasma treatment conditions. Many indicators are used to measure the activity of activated water, among which hydrogen peroxide, as a major liquid-phase active particle product, plays a key role in its activity and anti-cancer effect. Therefore, this embodiment approximates the comparison of the activity strength of plasma-activated water by measuring the concentration of liquid-phase hydrogen peroxide. Figure 3 It can be seen that oxygen is the strongest, followed by helium, then air, and nitrogen is the weakest. This is because oxygen is the direct raw material in the hydrogen peroxide generation process. The oxygen micro-nano bubbles and the large amount of dissolved oxygen they carry provide a sufficient oxygen source for the plasma discharge region to generate hydrogen peroxide.

[0058] Figure 4 The bar charts shown represent the differences in the physicochemical properties of the aqueous solution before and after plasma treatment. Figure 4 (a) in the chart corresponds to a comparison of pH values. Figure 4 (b) in the figure corresponds to the ORP value comparison chart. This chart shows that the aqueous solution was essentially neutral before plasma treatment, while it became weakly acidic after plasma treatment. Furthermore, both plasma activation and the introduction of micro / nano bubbles can increase the ORP of the aqueous solution, indicating enhanced oxidizing properties.

[0059] Figure 5 The figures show a comparison of the concentrations of major active particles in four different aqueous solutions before and after the introduction of micro / nano bubbles and before and after plasma treatment. (a) Figure shows a comparison of H2O2 concentration, and (b) Figure shows a comparison of NO2 concentration. - The concentration comparison chart, (c) is ONOO - / O2 - The graph shows a comparison of the concentrations of OH, with (d) being a comparison of the concentrations of OH. Figure 5 As can be seen, under the influence of the micro-nano bubble effect, the concentration of H2O2 particles in plasma-activated water only increases slightly, while the concentration of NO2... - ONOO - / O2 - The concentrations of both OH- and reactive particles increased significantly, with NO2 showing the most significant increase. - with ONOO - / O2 - The concentration of α increases by about 100%, while the concentration of OH increases by nearly 300%.

[0060] Figure 6 This is a graph showing the change in active particle concentration of the plasma-activated water prepared in this embodiment over a certain storage time. Room temperature storage can be considered to be around 25°C, while low-temperature storage refers to storing the plasma-activated water in a centrifuge tube under an ice-water bath, generally considered to be at 0°C. Figure 6 It can be seen that micro-nano bubbles and low-temperature environments are both beneficial to prolonging the lifespan of active particles and extending the effective period of chemical activity, and the combined use of the two has a better effect.

[0061] Figure 7 The immediate anticancer effects of water activated by different plasmas and the effects after storage for a certain period of time were shown. Figure 7 Figure (a) shows that plasma treatment of pure water containing micro- and nano-bubbles can reduce the activity of cancer cells more significantly, while Figure 7 Figure (b) shows that plasma-activated water containing micro-nano bubbles still has an inactivating effect on cancer cells after being stored for a certain period of time.

[0062] Figure 8 The image shows microscopic images of cancer cells treated with different aqueous solutions. The image shows that activated water with the introduction of micro-nano bubbles significantly reduces the number of cancer cells, which proves that it has a stronger anti-cancer effect.

[0063] In summary, the plasma treatment under the synergistic effect of micro-nano bubbles described in this embodiment is significantly more effective than plasma treatment without micro-nano bubbles. Therefore, if plasma-activated water with comparable activity is required, plasma discharge treatment under the synergistic effect of micro-nano bubbles can be carried out under lower treatment conditions, including lower discharge voltage or shorter discharge time. Experiments show that the voltage required to generate plasma without micro-nano bubbles is 13.2 kV, while the voltage required to generate plasma after introducing micro-nano bubbles is only 12.1 kV. Furthermore, the cancer cell viability was measured to be 73% after 5 minutes of plasma treatment without micro-nano bubbles, while it was 58% under the same conditions with micro-nano bubbles. If a 30% decrease in cancer cell viability is taken as the standard, this can be achieved with only about 3 minutes of discharge under conditions containing micro-nano bubbles.

[0064] This invention not only improves the practicality and efficiency of plasma-activated water, but also enhances its long-term storage effect. This is beneficial for the practical application of plasma-activated water and has significant implications for the field of plasma biomedicine, including sterilization, disinfection, anti-cancer, and wound treatment.

[0065] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for preparing plasma-activated water based on the synergistic effect of micro / nano bubbles, characterized in that, Includes the following steps: Micro-nano bubbles are passed through pure water until saturation is achieved to obtain micro-nano bubble water; the gas used for the micro-nano bubbles is one of air, oxygen, nitrogen, or helium. Plasma activation treatment was performed on micro-nano bubble water within 3 minutes to obtain plasma-activated water based on the synergistic effect of micro-nano bubbles.

2. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 1, characterized in that: Saturation refers to the fact that pure water appears completely opaque and milky white.

3. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 1, characterized in that: The micro-nano bubbles are generated by passing gas into a micro-nano bubble machine, and the gas flow rate into the micro-nano bubble machine is 180-220 sccm, with a passage time of 1-2 minutes.

4. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 3, characterized in that: The plasma activation treatment is performed using a single or multiple plasma jet devices arranged in an array, a coaxial circular tube plasma generator for dielectric barrier discharge, a surface discharge plasma generator, or a sliding arc discharge plasma generator.

5. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 3, characterized in that: The plasma activation treatment is performed using an underwater bubble plasma device.

6. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 5, characterized in that: The working gas introduced into the underwater bubble plasma device has a flow rate of 500 sccm to 5000 sccm; the working gas is helium-doped nitrogen gas, and the ratio of the two is 99:

1.

7. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 6, characterized in that: The flow rate of the working gas is 1000 sccm to 2000 sccm.

8. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to any one of claims 1 to 7, characterized in that: It also includes the steps of dispensing, sealing, and refrigerating plasma-activated water using centrifuge tubes.

9. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 8, characterized in that: The low temperature is 0–10°C.

10. The method for preparing plasma-activated water based on the synergistic effect of micro-nano bubbles according to claim 9, characterized in that: The low temperature is 4°C.

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