Portable normal-pressure microwave plasma low-temperature jet device for oral cavity

Abstract

The invention provides a portable normal-pressure microwave plasma low-temperature jet device for oral cavity, which comprises a coaxial transmission line structure, a bendable plasma excitation structure and a microwave source module, the microwave source module is connected with the input end of the coaxial transmission line structure, the plasma excitation structure is arranged at the output end of the coaxial transmission line structure, and the microwave source module is connected with the output end of the coaxial transmission line structure. The plasma excitation structure comprises a bendable metal conductor and an air entraining pipe arranged on the metal conductor, the metal conductor is connected with the inner conductor of the coaxial transmission line structure, and the air entraining pipe is connected with the outer conductor of the coaxial transmission line structure. When the device is used in a narrow oral cavity, the device can reach the deep area of the oral cavity through the bendable plasma excitation structure, and the application area is enlarged.

Description

Technical Field

[0001] The invention relates to the medical field, and in particular to a portable normal-pressure microwave plasma low-temperature jet device for oral cavity. Background Art

[0002] In recent years, the research on atmospheric pressure plasma has become increasingly popular and has considerable application value. It has also gradually attracted attention in many fields of biomedicine, such as disinfection, wound healing, blood coagulation, cancer treatment, immunotherapy, etc. Studies have shown that the effect of plasma treatment mainly depends on the chemical or physical reaction between the active substances (active oxides and active nitrides) or high-energy electrons in the plasma and the treated object. Microwave low-temperature plasma can increase the excitation, ionization and dissociation process of gas molecules. The plasma has high energy, many types of active particles, strong activity, and is easier to induce related physical and chemical reactions. Therefore, the application and development prospects of microwave atmospheric pressure plasma are broader.

[0003] Microwave atmospheric pressure plasma low temperature jet uses microwave energy to ionize the working gas in an open space to produce a low temperature plasma with a flame-like morphology. It has good application potential in the oral field, such as oral surgery trauma or hemostasis after tooth extraction and accelerated wound healing, reversible aphthous ulcers, oral leukoplakia treatment, head and neck squamous cell carcinoma treatment, periodontal inflammation treatment and root canal disinfection. Especially in the field of oral and maxillofacial trauma and oral tooth extraction, microwave atmospheric pressure low temperature plasma jet can have a better effect. Commonly used high-frequency electrocoagulation knife uses electric heat to coagulate small blood vessels, so that blood coagulation and carbonization can achieve the purpose of hemostasis, but it is easy to cause tissue burning. And when the mouth is moist and in motion, the local charred tissue is easy to fall off, causing new bleeding. Another low-temperature plasma radiofrequency ablation method uses a certain frequency to excite plasma to cut the tissue and achieve the effect of ablating the tissue. In contrast, microwave atmospheric pressure low temperature plasma jet not only does not cause cutting damage to the tissue, but also because of its low gas temperature, it does not generate high heat to coagulate the tissue or damage the local tissue, thereby hindering the further healing of the wound. It can accelerate blood coagulation by activating platelets, promoting platelet aggregation, and promoting blood dehydration. There will be no side effects during the treatment process, such as heat generation, gasification, carbonization, bacterial contamination, etc. At the same time, active particles such as reactive oxygen and reactive nitrogen generated by plasma can mediate a series of core cell behaviors such as proliferation, migration, and differentiation of wound healing, thereby promoting rapid tissue healing.

[0004] However, there are many limitations in using microwave atmospheric pressure low-temperature plasma jet in the oral field, so there is no practical application in the oral field at present. The difficulties are as follows:

[0005] First of all, the existing microwave atmospheric pressure plasma jet sources are almost all simple metal coaxial structures. The plasma jet generated can only be ejected vertically outward and cannot change its direction at will, which seriously limits the application scenarios of the plasma source. Especially when used in a relatively narrow oral cavity, the vertically ejected plasma jet is difficult to reach the deep areas of the oral cavity, such as the upper and lower third molar areas, which limits its effectiveness. Secondly, the existing microwave atmospheric pressure plasma jet sources all need to use commercial microwave sources to feed microwave energy from the outside, which makes the entire microwave atmospheric pressure plasma system bulky and expensive.

[0006] Therefore, how to design a suitable microwave atmospheric pressure low-temperature plasma jet source is the core of whether this technology can be promoted. For actual clinical applications, the microwave atmospheric pressure plasma jet source should be applicable to multiple clinical application scenarios, portable, safe, stable, efficient and low-cost. Summary of the invention

[0007] The present invention provides a portable normal-pressure microwave plasma low-temperature jet device for oral use to solve at least one of the above-mentioned technical problems.

[0008] To solve the above problems, as one aspect of the present invention, a portable normal-pressure microwave plasma low-temperature jet device for oral use is provided, comprising: a coaxial transmission line structure, a bendable plasma excitation structure and a microwave source module, wherein the microwave source module is connected to the input end of the coaxial transmission line structure, the plasma excitation structure is arranged at the output end of the coaxial transmission line structure, the plasma excitation structure comprises a bendable metal conductor and an air duct arranged on the metal conductor, the metal conductor is connected to the inner conductor of the coaxial transmission line structure, and the air duct is connected to the outer conductor of the coaxial transmission line structure. Preferably, the metal conductor is made of copper, aluminum, or iron.

[0009] Preferably, the air duct is made of plastic or metal.

[0010] Preferably, the coaxial transmission line structure comprises a first coaxial transmission line, a second coaxial transmission line, a third coaxial transmission line, a tapered coaxial compression section and a fourth coaxial transmission line which are connected in sequence.

[0011] Preferably, the first coaxial transmission line is filled with air, the second coaxial transmission line is filled with Teflon, and the third coaxial transmission line, the tapered coaxial compression section and the fourth coaxial transmission line are all filled with working gas.

[0012] Preferably, the first coaxial transmission line, the second coaxial transmission line and the third coaxial transmission line have different sizes.

[0013] Preferably, air inlet pipes are symmetrically arranged on both sides of the third coaxial transmission line in the circumferential direction.

[0014] Due to the adoption of the above technical solution, when the present invention is used in a relatively narrow oral cavity, it can reach the deep area of ​​the oral cavity through the flexible plasma excitation structure, thereby increasing the application area. In addition, the built-in microwave source module does not need to use a commercial microwave source to feed microwave energy from the outside, making the entire microwave atmospheric pressure plasma system more portable and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The overall structural diagram of the present invention is schematically shown;

[0016] Figure 2 A cross-sectional view of the present invention is schematically shown.

[0017] The reference numerals in the figure are: 1. air inlet pipe; 2. coaxial transmission line structure; 3. plasma excitation structure; 4. microwave source module; 5. metal conductor; 6. air bleed pipe; 7. inner conductor; 8. outer conductor; 9. first coaxial transmission line; 10. second coaxial transmission line; 11. third coaxial transmission line; 12. gradient coaxial compression section; 13. fourth coaxial transmission line. DETAILED DESCRIPTION

[0018] The following is a detailed description of embodiments of the present invention, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0019] As one aspect of the present invention, a portable normal-pressure microwave plasma low-temperature jet device for oral use is provided, which is applied to local biological medical treatment of the oral cavity, and comprises: a coaxial transmission line structure 2, a flexible plasma excitation structure 3 and a microwave source module 4, wherein the microwave source module 4 is connected to the input end of the coaxial transmission line structure 2, the plasma excitation structure 3 is arranged at the output end of the coaxial transmission line structure 2, the plasma excitation structure 3 comprises a flexible metal conductor 5 and an air duct 6 arranged on the metal conductor 5, the metal conductor 5 is connected to the inner conductor 7 of the coaxial transmission line structure 2, and the air duct 6 is connected to the outer conductor 8 of the coaxial transmission line structure 2.

[0020] Preferably, the microwave source module 4 is a solid-state module, which is directly connected to the coaxial transmission line structure to provide microwave power.

[0021] The bendable plasma excitation structure 3 can focus microwave energy on the tip of the conductor in the bend structure, forming a higher field strength, which is beneficial to plasma excitation and the adjustment of the direction and morphology of the plasma jet.

[0022] Preferably, the metal conductor 5 is made of copper, aluminum or iron. Preferably, the air duct 6 is made of plastic or metal.

[0023] Preferably, the coaxial transmission line structure 2 comprises a first coaxial transmission line 9, a second coaxial transmission line 10, a third coaxial transmission line 11, a tapered coaxial compression section 12 and a fourth coaxial transmission line 13 connected in sequence. Preferably, the first coaxial transmission line 9 is filled with air, the second coaxial transmission line 10 is filled with Teflon, and the third coaxial transmission line 11, the tapered coaxial compression section 12 and the fourth coaxial transmission line 13 are all filled with working gas. Preferably, the first coaxial transmission line 9, the second coaxial transmission line 10 and the third coaxial transmission line 11 have different sizes. In particular, the characteristic impedance of all sections of the coaxial transmission line structure 2 is 50Ω, and the sizes of its inner and outer conductors meet the impedance requirements.

[0024] Preferably, the third coaxial transmission line 11 is symmetrically provided with air inlet pipes 1 on both sides of the circumference. The inclined air inlet pipe 1 holes are provided at symmetrical positions on both sides of the coaxial line, and the gas enters the coaxial cavity to form a stable airflow, which is convenient for exciting the plasma.

[0025] When working, the device is supplied with commercial power, and then gas is injected from the air inlet pipe 1, and the switch of the microwave source module 4 is turned on. The microwave energy is focused on the bent structure terminal of the bendable plasma excitation structure 3, so that the electric field intensity here is very high, which is conducive to ionizing the gas to generate plasma.

[0026] Due to the adoption of the above technical solution, when the present invention is used in a relatively narrow oral cavity, it can reach the deep area of ​​the oral cavity through the flexible plasma excitation structure, thereby increasing the application area. In addition, the built-in microwave source module does not need to use a commercial microwave source to feed microwave energy from the outside, making the entire microwave atmospheric pressure plasma system more portable and reducing costs.

[0027] In one embodiment, the microwave source is a solid-state source, the microwave power is adjustable, the frequency is 2450 MHz, the angle between the air inlet pipe and the outer conductor is adjustable, and there is no fixed requirement for the type of excitation gas used, which can be air, argon, helium, nitrogen, etc., or a mixed gas, and the flow rate of the gas is adjustable. The microwave power can be adjusted according to the type of gas passed, or different microwave powers can be used for the same gas to obtain plasmas with different properties.

[0028] Experimental example: A microwave low-temperature plasma device was used to optimize the conditions for promoting the adhesion and proliferation of human gingival fibroblasts.

[0029] 1. Experimental Methods

[0030] 1. Effect of microwave low-temperature plasma device on the activity and proliferation ability of human gingival fibroblasts.

[0031] Human gingival fibroblasts, the core cells for soft tissue healing and closure of tooth extraction sockets, were cultured and inoculated in a 24-well plate at a density of 5×104 cells per well. After plasma treatment of the cells (treatment time was 0s, 15s, 30s, 1min, 2min, 3min, 4min, and 5min, channel frequency was 2400MHz, channel power was 25W, and spray distance was 5mm), OD values ​​were detected using CCK-8 kit 1, 2, and 3 days after treatment, and cells were stained with live and dead dye to screen plasma treatment conditions that promote the proliferation of human gingival fibroblasts.

[0032] 2. The effect of microwave low-temperature plasma device on the level of reactive oxygen species in human gingival fibroblasts.

[0033] Human gingival fibroblasts were cultured and seeded in a 96-well plate at a density of 4×103 cells per well. After the cells were treated with plasma (treatment time was 0 s, 15 s, 30 s, 1 min, 2 min, and 3 min, channel power was 25 W, and injection distance was 5 mm), the fluorescent probe DCFH-DA was used to detect the level of intracellular reactive oxygen species, and the nitric oxide detection kit was used to detect the level of intracellular nitric oxide, and the plasma treatment condition with the strongest ability to produce reactive oxygen species was screened.

[0034] 3. The effect of microwave low-temperature plasma device on adhesion-related genes in human gingival fibroblasts.

[0035] Human gingival fibroblasts were cultured and seeded in 6-well plates at a density of 1×105 cells per well. After plasma treatment (treatment time was 0s, 30s, 1min, 2min, 3min, and 4min, channel power was 25W, and injection distance was 5mm), the cells were cultured for 1 and 3 days and RNA was extracted. RT-qPCR was used to detect the expression of adhesion-related genes in human gingival fibroblasts to screen the plasma treatment conditions with the strongest adhesion promotion.

[0036] 2. Experimental Results

[0037] Human gingival fibroblasts are one of the core cells for wound healing in the oral cavity, especially for wound healing of tooth extraction. Compared with other conditions, low-temperature atmospheric pressure plasma treatment of human gingival fibroblasts for more than 30 seconds can effectively promote cell proliferation, while effectively enhancing the level of intracellular reactive oxygen species and promoting the expression of adhesion-related genes in human gingival fibroblasts. That is, the microwave low-temperature plasma device treatment time of 2 minutes, channel power of 25W, and injection distance of 5mm are the best conditions, which also shows that the low-temperature atmospheric pressure plasma device treatment has a good promoting effect on the adhesion of human gingival fibroblasts in vitro.

[0038] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0039] (1) Microwave low-temperature plasma can increase the excitation, ionization, and dissociation process of gas molecules. It excites more substate atoms, and its degree of ionization and dissociation of gas is one order of magnitude higher than other types of plasma (such as radio frequency electric field plasma). The plasma has high density, high ionization degree, high energy, and strong activity, making it easier to cause or trigger related physical and chemical reactions. Therefore, it is more efficient in medical treatments that rely on plasma active components.

[0040] (2) The structure of the device is compact, small, easy to carry, and easy to assemble and mass produce. The air guide holes of the outer conductor are cleverly arranged. The air guide holes are arranged at both ends of the outer conductor column and are obliquely inserted into the cavity formed by the inner conductor and the outer conductor at a certain angle. The air guide holes move along the inner conductor column toward the discharge tip in a spiral manner, which stabilizes the flow of the airflow to a certain extent, making the airflow at the tip more stable, so that the plasma beam can be stably output.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A portable atmospheric pressure microwave plasma cryogenic jet device for oral use, characterized in that, it includes: a coaxial transmission line structure (2), a bendable plasma excitation structure (3) and a microwave source module (4). The microwave source module (4) is connected to the input end of the coaxial transmission line structure (2), and the plasma excitation structure (3) is arranged at the output end of the coaxial transmission line structure (2). The plasma excitation structure (3) includes a bendable metal conductor (5) and an air intake pipe (6) arranged on the metal conductor (5). The metal conductor (5) is connected to the inner conductor (7) of the coaxial transmission line structure (2), and the air intake pipe (6) is connected to the outer conductor (8) of the coaxial transmission line structure (2).

2. The portable atmospheric pressure microwave plasma cryogenic jet device for oral use according to claim 1, characterized in that, the metal conductor (5) is made of copper, or aluminum, or iron.

3. The portable atmospheric pressure microwave plasma cryogenic jet device for oral use according to claim 1, characterized in that, the air intake pipe (6) is made of plastic or metal.

4. The portable atmospheric pressure microwave plasma cryogenic jet device for oral use according to claim 1, characterized in that, the coaxial transmission line structure (2) includes a first coaxial transmission line (9), a second coaxial transmission line (10), a third coaxial transmission line (11), a tapered coaxial compression section (12) and a fourth coaxial transmission line (13) connected in sequence.

5. The portable atmospheric pressure microwave plasma cryogenic jet device for oral use according to claim 4, characterized in that, air is filled in the first coaxial transmission line (9), Teflon is filled in the second coaxial transmission line (10), and working gas is filled in the third coaxial transmission line (11), the tapered coaxial compression section (12) and the fourth coaxial transmission line (13).

6. The portable atmospheric pressure microwave plasma cryogenic jet device for oral use according to claim 5, characterized in that, the first coaxial transmission line (9), the second coaxial transmission line (10) and the third coaxial transmission line (11) have different dimensions.

7. The portable atmospheric pressure microwave plasma cryogenic jet device for oral use according to claim 5, characterized in that, air intake pipes (1) are symmetrically arranged on both circumferential sides of the third coaxial transmission line (11).

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