Method for prolonging service life of dynamic sealing ring of medical rotary cutting device through magnetic particles and medical rotary cutting device

Abstract

The invention relates to a method for prolonging the service life of a movable sealing ring of a medical rotary cutting device through magnetic particles and the medical rotary cutting device. The method comprises the steps that a glue injection hole is formed in the waste liquid inlet end of a bearing sleeve in the rotary cutting device, and one end of the glue injection hole communicates with a cavity, close to a waste liquid inlet, of the movable sealing ring; injecting a heat conduction agent into the glue injection hole, and curing the heat conduction agent, so that the heat conduction agent is cured in the glue injection hole; the heat conduction agent comprises magnetic particles, and the magnetic particles are dissolved in normal saline or heparin saline and can directionally flow to the movable sealing ring cavity in an external magnetic field. According to the method provided by the invention, for the medical rotary cutting device using the movable sealing ring at the high rotating speed, the heating problem of the working area of the movable sealing ring can be reduced, and the service life of the movable sealing ring at the high rotating speed is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a method for extending the service life of a dynamic sealing ring of a medical rotary cutting device by using magnetic particles and the medical rotary cutting device. Background Art

[0002] Atherectomy is a procedure that uses the distal end of a catheter to cut atherosclerotic plaques that block blood vessels in a high-speed, directional manner to restore blood flow. Compared with traditional thrombus removal methods, atherectomy has higher removal efficiency and lower surgical risks.

[0003] Among them, the stable rotation speed of the cutter head is an important parameter to ensure the safety of the peeling product and its therapeutic effect. Generally speaking, the rotation speed of the cutter head is relatively high, which can reach 40,000-60,000 rpm. At such a high rotation speed, the inner ring of the dynamic seal ring of the peeling equipment and the transmission shaft will generate a lot of heat due to intense friction and heat up. On the one hand, high temperature will inevitably reduce the life of the dynamic seal ring, thereby affecting the sealing effect. On the other hand, GB 9706.1-2020 stipulates that the maximum temperature of the plastic casing of medical electrical equipment cannot exceed 48°C. This makes it particularly important to control the temperature of the working area of ​​the dynamic seal ring.

[0004] For example, CN108852480A discloses a tissue peeling device, in which a sealing ring is sleeved on one end of the connecting tube and is inserted into the piston cylinder in a sealing and sliding manner, and CN116549064A discloses a peeling device, in which a rubber sealing ring is provided between the peeling tube and the side wall hole of the suction chamber to prevent the suction material from entering and interfering with the driving gear and the driven gear transmission. However, the above peeling products do not pay attention to the problem of frictional heat generation in the working area of ​​the sealing ring, and are not suitable for high-speed application scenarios.

[0005] In addition, some existing rotary cutting products avoid using dynamic sealing rings to circumvent the problem that dynamic sealing rings are prone to failure at high speeds. For example, Phoenix's rotary cutting products have a low rotation speed and average suction effect, so ordinary sealing rings can be used to prevent leakage; Boco's Jetstream avoids leakage problems by connecting an external negative pressure pump and controlling the flow of the liquid; BD's Rotarex separates the power input end and the transmission output end into two parts, which are transmitted through a magnetic coupling, so that the sucked liquid is completely collected in the outer casing of the transmission output end. However, the presence of the magnetic coupling limits the overall load of the rotary cutting product. When the rotary cutting cutter head encounters a harder plaque, the product may stop running.

[0006] Therefore, how to reduce the heat generated by the dynamic seal ring and extend its service life is a technical problem that needs to be solved in the current field. Summary of the invention

[0007] In view of the above problems, the purpose of the present invention is to provide a method for extending the life of a dynamic sealing ring of a medical peeling device by using magnetic particles and a medical peeling device. Compared with the prior art, the method provided by the present invention is aimed at a medical peeling device that operates at a high speed (a speed of 40,000-60,000 rpm) and uses a dynamic sealing ring, which can reduce the heating problem in the working area of ​​the dynamic sealing ring and extend the service life of the dynamic sealing ring at high speed.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles, the method comprising:

[0010] A glue injection hole is provided at the waste liquid inlet end of the bearing sleeve in the rotary cutting device, and one end of the glue injection hole is connected to the chamber of the dynamic sealing ring close to the waste liquid inlet;

[0011] Injecting a thermal conductive agent into the glue injection hole, and curing the thermal conductive agent so that the thermal conductive agent is cured in the glue injection hole;

[0012] The thermal conductive agent comprises magnetic particles, and the magnetic particles are dissolved in physiological saline or heparin saline;

[0013] Preferably, the method further comprises controlling the movement of magnetic particles in the thermal conductive agent to the dynamic sealing ring chamber by applying an external magnetic field.

[0014] In the method provided by the present invention, magnetic particles with heat transfer properties are arranged near the dynamic sealing ring. The magnetic particles have biocompatibility and can be discharged along with the waste liquid to take away the heat, thereby avoiding the problem of high-temperature heat accumulation when the dynamic sealing ring rotates at high speed. Furthermore, by applying an external magnetic field, the magnetic particles are directed to flow to the dynamic sealing ring chamber under the action of the magnetic field, thereby avoiding the loss of the heat conductor and improving the thermal conductivity efficiency.

[0015] Specifically, the existing medical rotary cutting device includes a bearing sleeve and a drainage cavity, and the end face of the bearing sleeve close to the waste liquid inlet is arranged inside the drainage cavity. The present invention opens a glue injection hole on the end face, and in the device manufacturing stage, a thermal conductor is injected into the glue injection hole, and the thermal conductor contains magnetic particles with good thermal conductivity and biocompatibility; before the rotary cutting device is used, the characteristic of magnetic particles being soluble in physiological saline or heparin saline is utilized to inject 25°C physiological saline or heparin saline into the drainage cavity to remove the air in the bearing sleeve and the drainage cavity. In this process, physiological saline enters the glue injection hole along the gap between the bearing sleeve and the transmission shaft and releases the magnetic particles. Since one end of the glue injection hole is connected to the dynamic sealing ring chamber, the magnetic particles enter the vicinity of the dynamic sealing ring chamber; when the rotary cutting device is started, Under the suction effect of negative pressure (during the operation of the rotary cutting device, the space within the inner blade of the rotary cutting cutter head is a negative pressure environment through the rotation of the spiral rod line), the magnetic particles enter the dynamic sealing ring chamber, and the magnetic particles use their own thermal conductivity to absorb the heat of the dynamic sealing ring. As the spiral rod line rotates, the waste liquid is continuously sucked into the dynamic sealing ring chamber, so that some magnetic particles that are not completely dissolved and released are sucked into the waste liquid of the dynamic sealing chamber and continue to be dissolved and released, so that free magnetic particles always exist in the drainage chamber of the rotary cutting device during operation. At this time, the friction heat generated by the dynamic sealing ring is conducted to the magnetic particles, and the magnetic particles after heat exchange are discharged from the rotary cutting device through the drainage hose of the drainage chamber with the waste liquid, thereby continuously taking away the heat and avoiding the dynamic sealing ring chamber from accumulating heat and causing the temperature to be too high. In this process, most of the magnetic particles will be discharged through the drainage hose, and only a very small amount will enter the human body, and the magnetic particles used in the present invention have good biocompatibility and will not cause harm to the human body. In addition, the magnetic particles used in the present invention have magnetism under the condition of an external magnetic field, and their application in vivo has more unique advantages.

[0016] In the present invention, in order to strictly control the amount of magnetic particles entering the human body, that is, to avoid the thermal conductor from being lost too quickly, the present invention preferably applies a magnetic field externally, and causes the magnetic particles to flow into the dynamic sealing ring chamber under the action of the magnetic field. It should be noted that: under the condition of no magnetic field, the magnetic particles will also flow into the dynamic sealing ring chamber under the action of negative pressure, but their movement is relatively random, and the magnetic particles are in a free state. The present invention can control the "directional flow" of the magnetic particles by applying an external magnetic field, that is, the magnetic moment inside the magnetic particles is subjected to the force of the magnetic field so that the magnetic particles move along the magnetic field lines to the dynamic sealing ring and contact it. The magnetic particles in the magnetic field are distributed in a chain shape, so that the friction heat generated by the dynamic sealing ring is directly conducted to the magnetic particle chain, which is different from the process in which most of the heat of the dynamic sealing ring needs to be first transferred to the fluid and then transferred from the fluid to the magnetic particles when there is no magnetic field. The heat conduction efficiency is higher when no fluid medium is required; on the other hand, under the action of the external magnetic field, the magnetic particles can maintain directional flow in the dynamic sealing ring chamber, reducing the loss discharged with the waste liquid, so that the accumulated heat is continuously transferred to the waste liquid through the magnetic particles, and a relatively excellent thermal conductivity is maintained. In the present invention, it is generally preferred to control the strength of the external magnetic field to be 600-1200Gs, for example, it can be 600Gs, 700Gs, 800Gs, 900Gs, 1000Gs, 1100Gs or 1200Gs, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable, and the direction is from the distal end to the proximal end. The proximal end referred to in the present invention is the side close to the operator, and correspondingly, the distal end refers to the side away from the operator.

[0017] Preferably, the glue injection holes are evenly distributed along the rotation center of the bearing sleeve.

[0018] In the present invention, the number of glue injection holes can be selected and set according to the size of the rotary cutting device. The glue injection holes need to be as close to the transmission shaft as possible, and the wall thickness of the bearing sleeve needs to be ensured. Generally, the distance between the center of the glue injection hole and the center of the bearing sleeve is controlled to be 0.8 mm. The glue injection holes can be processed by laser processing, and the glue injection holes are only used to store thermal conductive agent.

[0019] Preferably, the depth of the glue injection hole is 0.5-1 mm, for example, it can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] Preferably, the inner diameter of the glue injection hole is 0.1-0.3 mm, for example, it can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the glue injection holes are evenly distributed along the rotation center of the bearing sleeve and the number is 8-12, for example, 8, 9, 10, 11 or 12, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the magnetic particles include Fe3O4 nanoparticles.

[0023] Preferably, the particle size of the Fe3O4 nanoparticles is 10-30 nm, for example, it can be 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm or 30 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In the present invention, Fe3O4 nanoparticles are preferably used because of their advantages such as high surface area to volume ratio, low toxicity and high targeting. For example, Fe3O4 nanoparticles can be used as contrast agents, indicating that they have good biocompatibility and can play an important role in the field of biomedicine. More importantly, Fe3O4 nanoparticles have lubricity and excellent thermal conductivity, and the thermal conductivity increases with the increase of the external magnetic field. Under the condition of an external magnetic field, Fe3O4 nanoparticles can be more accurately guided to continuously enter the inlet end of the dynamic seal ring chamber, and directional flow can be maintained in the dynamic seal ring chamber, thereby better exerting the thermal conductivity and lubricity of Fe3O4 nanoparticles, better solving the problem of excessive local heating of the rotary cutting device containing the dynamic seal ring, and extending the service life of the dynamic seal ring. Furthermore, the present invention preferably controls the particle size of the Fe3O4 nanoparticles to be 10-30nm. When the particle size of the Fe3O4 nanoparticles is less than 10nm, the particles are extremely small and have a large surface energy, so they are prone to agglomeration. Even if the agglomeration problem can be avoided after modification, the extremely small particle size of 10nm may also cause the accumulation of nanoparticles in specific tissues. Due to their large specific surface area and high reactivity, they are more likely to interact with cell membranes, thereby increasing the risk of biological toxicity; when the particle size of the Fe3O4 nanoparticles is greater than 30nm, as the particle size increases, the surface area and volume ratio of the particles decreases, and the amount of the modifier (such as PEG) bound to the nanoparticles decreases, which will also cause the Fe3O4 nanoparticles to agglomerate, making it difficult to meet the requirements of biocompatibility. At the same time, Fe3O4 nanoparticles that are too large are difficult to be excreted from the body through human metabolism, which will cause certain safety hazards.

[0025] Preferably, the surface of the Fe3O4 nanoparticles is sequentially modified with a coating layer and a controlled release layer.

[0026] Preferably, the material of the coating layer includes polyethylene glycol or polylactic acid-glycolic acid copolymer.

[0027] Preferably, the material of the controlled release layer includes hydroxypropyl methylcellulose.

[0028] In view of the fact that unmodified Fe3O4 nanoparticles have toxic side effects on the immune system, nervous system, circulatory system, etc., the Fe3O4 nanoparticles used in the present invention are pre-surface modified, preferably the coating layer and the controlled release layer are modified in sequence.

[0029] In the present invention, the coating layer is preferably modified with polyethylene glycol or polylactic acid-glycolic acid copolymer, which can prevent exogenous Fe3O4 nanoparticles from being adsorbed by plasma proteins when entering the body, and then being recognized by organs rich in reticuloendothelial cells and non-specifically phagocytosed. The methods of modifying Fe3O4 nanoparticles with polyethylene glycol (PEG) and polylactic acid-glycolic acid copolymer (PLGA) are conventional methods in the art, such as electrospraying, rotary evaporation, and coprecipitation; in the present invention, the controlled release layer is preferably modified with hydroxypropyl methylcellulose (HPMC), which is one of the most widely used pharmaceutical excipients in the art and has excellent cold water solubility. When added to cold water and stirred slightly, it can be dissolved into a transparent solution. On the contrary, it is basically insoluble in hot water above 60°C and can only swell.

[0030] Preferably, the thermal conductor is a HPMC-PEG-Fe3O4 nanoparticle solution obtained by adding polyethylene glycol-modified Fe3O4 nanoparticles into a hydroxypropyl methylcellulose solution and dispersing the obtained nanoparticles.

[0031] In the present invention, the hydroxypropyl methylcellulose solution is preferably an aqueous solution of HPMC E5 (E5 means low viscosity) with a mass concentration of 1-2% at 20° C. The mass concentration can be, for example, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. The viscosity is usually 4-6cp, for example, 4cp, 4.2cp, 4.4cp, 4.5cp, 4.6cp, 4.8cp, 5cp, 5.2cp, 5.4cp, 5.5cp, 5.6cp, 5.8cp or 6cp, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. Taking 1% HPMC E5 solution as an example, its preparation method may be: take 1g HPMC, slowly add it into 50mL hot water at 80°C to dissolve, and use a mechanical stirrer to stir continuously to prevent agglomeration, at this time, HPMC suspension is formed; then the HPMC suspension is cooled to room temperature, and 50mL of water at 25°C is added, and stirring is continued with a stirrer until HPMC is completely dissolved and the solution is uniform without bubbles, thereby obtaining 1% HPMC E5 solution.

[0032] In the present invention, the HPMC-PEG-Fe3O4 nanoparticles are Fe3O4 nanoparticles modified by PEG and HPMC in sequence, wherein Fe3O4 is wrapped by PEG and is limited by the solubility of HPMC at different temperatures. When the temperature is 25-50°C, HPMC is easily soluble in water or ethanol and other solvents, so that the Fe3O4 nanoparticles are released; when the temperature reaches 60°C or higher, HPMC is not easily soluble in water or ethanol and other solvents, and is gelled, making it difficult to release the Fe3O4 nanoparticles. By utilizing the characteristic that the solubility of HPMC changes with temperature, the controlled release of Fe3O4 nanoparticles can be formed.

[0033] Preferably, mechanical stirring or ultrasound is performed during the dispersing process.

[0034] Preferably, the mechanical stirring time is 10-30 min, for example, 10 min, 20 min or 30 min, and the ultrasonic time is 10-20 min, for example, 10 min, 15 min or 20 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the volume fraction of Fe3O4 nanoparticles in the thermal conductor is 0.01-0.025%, for example, it can be 0.01%, 0.012%, 0.014%, 0.016%, 0.018%, 0.02%, 0.022%, 0.024% or 0.025%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In the present invention, the volume fraction of Fe3O4 nanoparticles in the thermal conductor is preferably controlled to be 0.01-0.025%. On the one hand, when the thermal conductor is in the fluid, the viscosity, concentration and temperature of the fluid will affect the heat transfer characteristics of the fluid. The present invention helps to maintain the stability of the fluid and reduce the negative impact of exogenous nanoparticles on the organism by preferably controlling the Fe3O4 nanoparticles to occupy a lower volume fraction (such as 0.01-0.025%); on the contrary, when the volume fraction of Fe3O4 nanoparticles exceeds 0.025%, the particle agglomeration phenomenon will increase, and the agglomerated nanoparticles are likely to induce immune response and inflammation risks; in addition, the particle size of the agglomerated Fe3O4 nanoparticles increases, and after entering the body, they may be trapped in the liver and spleen and are difficult to be excreted from the body, thereby resulting in a decrease in the biocompatibility of the nanoparticles. On the other hand, when the volume fraction of Fe3O4 nanoparticles is controlled to be 0.01-0.025% in the present invention, its thermal conductivity is significantly improved compared with that without adding Fe3O4 nanoparticles, and the thermal conductivity effect is stable, which can make the service life of the dynamic sealing ring reach more than 35.7 minutes, and the wear rate of the dynamic sealing ring in 20 minutes reach less than 0.586%, thereby obtaining excellent thermal conductivity and dynamic sealing ring life.

[0037] Preferably, the curing temperature is 60-80°C, for example, it can be 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the curing time is 1.5-2 hours, for example, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] In the present invention, a syringe can be used to inject the thermal conductor into the injection hole of the bearing sleeve (generally made of polycarbonate) so that the injection hole is filled with the thermal conductor, the bearing sleeve is placed at room temperature to dry, most of the solvent is removed, and then the dried substrate is placed in an oven and cured at 60-80°C for 1.5-2h, so that the HPMC-PEG-Fe3O4 nanoparticles can be completely cured in the injection hole of the bearing sleeve.

[0040] In a second aspect, the present invention provides a medical peeling device, which is used for the method of extending the life of a dynamic sealing ring of a medical peeling device by using magnetic particles as described in the first aspect of the present invention; the medical peeling device comprises a bearing sleeve and a drainage chamber; the end face of the bearing sleeve close to the waste liquid inlet is arranged inside the drainage chamber and a glue injection hole is provided on the end face, and one end of the glue injection hole is connected to the chamber of the dynamic sealing ring close to the waste liquid inlet; the dynamic sealing ring is arranged between the bearing sleeve and the transmission shaft, and the transmission shaft passes through the dynamic sealing ring.

[0041] In the medical rotary cutting device provided by the present invention, the setting of the glue injection hole and its position provides conditions for the thermal conductive agent to exert its thermal conductivity and lubricity, which can take away the heat generated by the intense friction between the dynamic sealing ring and the transmission shaft, extend the service life of the dynamic sealing ring, and avoid increasing the complexity of the rotary cutting device.

[0042] Preferably, the medical peeling device also includes a driving mechanism and a peeling mechanism; the driving structure includes a motor, and the motor drives a transmission shaft through gears; the peeling mechanism includes a peeling cutter head, and the peeling cutter head is connected to the transmission shaft in the drainage chamber through a welding component, and a drainage hose is provided in the drainage chamber.

[0043] In the present invention, the space within the inner blade of the rotary cutting cutter head is a negative pressure environment to provide a power basis for injecting the heat conductive agent into the dynamic sealing ring chamber, while the drainage cavity and the drainage hose provide conditions for the release and discharge of magnetic particles.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) In the method provided by the present invention, the thermal conductive agent used has good biocompatibility and can enter the human body through blood vessels without increasing additional surgical risks.

[0046] (2) In the method provided by the present invention, the thermal conductive agent is pre-injected into the rotary cutting device. On the one hand, the load place of the thermal conductive agent is set based on the structural characteristics of the rotary cutting device itself, without increasing the complexity of the rotary cutting device; on the other hand, the thermal conductive agent is released only when liquid enters the bearing sleeve from the outside, thereby ensuring the use efficiency and safety of the magnetic particles. The magnetic particles Fe3O4 also have excellent lubricity, which can quickly take away a large amount of heat generated by the friction between the inlet end of the dynamic sealing ring and the transmission shaft, while reducing the wear between the inlet end of the dynamic sealing ring and the transmission shaft, thereby increasing the service life of the dynamic sealing ring; further, the present invention can also apply a magnetic field to the outside of the rotary cutting device. Under the action of the magnetic field, the thermal conductivity of the magnetic particles is even better, and the magnetic particles can be more accurately guided to continuously enter the dynamic sealing ring chamber, so as to better utilize the thermal conductivity and lubricity of the magnetic particles, and better solve the problems of excessive local heating of the dynamic sealing ring of the rotary cutting product and the short service life of the dynamic sealing ring.

[0047] (3) In the method provided by the present invention, the thermal conductor is pre-injected into the bearing sleeve and solidified, and the amount of thermal conductor used can be adjusted according to the expected duration of the operation to avoid waste or shortage of the thermal conductor. The magnetic particles can also be kept in a directional flow in the dynamic sealing ring chamber under the action of an external magnetic field, thereby maintaining the thermal conductivity efficiency without losing the thermal conductor.

[0048] (4) In the method and the peeling device provided by the present invention, only the glue injection hole needs to be opened in the bearing sleeve, and no other structure of the peeling device needs to be improved, which does not affect the sealing effect of the dynamic sealing ring.

[0049] (5) The method and peeling device provided by the present invention can achieve a thermal conductivity of 0.697 W·m -1 ·K -1 The service life of the dynamic seal ring is more than 35.7 minutes, the wear rate of the dynamic seal ring is less than 0.586% after 20 minutes of operation, and the temperature of the handle shell at the position of the dynamic seal ring is less than 29.3°C after 20 minutes of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of the structure of the medical rotary cutting device after the HPMC-PEG-Fe3O4 nanoparticles are released in Example 1 of the present invention;

[0051] Figure 2 For the present invention Figure 1 The enlarged view of point I in the middle;

[0052] Figure 3 This is a schematic structural diagram of the end surface of the bearing sleeve close to the waste liquid inlet according to Example 1 of the present invention;

[0053] Among them, 1-transmission shaft; 2-bearing sleeve; 3-dynamic seal ring; 4-HPMC-PEG-Fe3O4 nanoparticles; 5-welding component; 6-drain hose; 7-drain chamber; 8-rotary cutter head; 9-gear; 10-motor; 11-glue injection hole; 12-dynamic seal ring chamber;

[0054] Figure 4 The thermal conductivity result diagram of the thermal conductive agent in Examples 1-3, Examples 7-10 and Comparative Example 1 of the present invention;

[0055] Figure 5 The temperature result diagram of the handle shell at the dynamic seal ring position when running for 20 minutes in Examples 1-10 of the present invention and Comparative Examples 1-4;

[0056] Figure 6 The result diagram of the life of the dynamic seal ring in Examples 1-10 of the present invention and Comparative Examples 1-4;

[0057] Figure 7 The graph is a result of the wear rate of the dynamic seal rings in Examples 1-10 of the present invention and Comparative Examples 1-4 after running for 20 minutes. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0059] In one specific embodiment, a medical rotary cutting device is provided, wherein the medical rotary cutting device is used to extend the life of a dynamic sealing ring of the medical rotary cutting device by using magnetic particles, such as Figure 1 As shown, the medical rotary cutting device includes a bearing sleeve 2 and a drainage chamber 7. Figure 2 and Figure 3 As shown, the end face of the bearing sleeve 2 close to the waste liquid inlet is arranged inside the drainage chamber 7 and the end face is provided with a glue injection hole 11, one end of the glue injection hole 11 is connected with the dynamic sealing ring chamber 12 of the dynamic sealing ring 3 close to the waste liquid inlet, the dynamic sealing ring 3 is arranged between the bearing sleeve 2 and the transmission shaft 1, the transmission shaft 1 passes through the dynamic sealing ring 3, the medical peeling device also includes a driving mechanism and a peeling mechanism, the driving structure includes a motor 10, the motor 10 drives the transmission shaft 1 through a gear 9, the peeling mechanism includes a peeling cutter head 8, the peeling cutter head 8 is connected to the drainage chamber 7 with the transmission shaft 1 through a welding component 5, and a drainage hose 6 is arranged in the drainage chamber 7.

[0060] In the medical rotary cutting device provided by the present invention, the injection hole 11 is filled with a thermal conductor containing HPMC-PEG-Fe3O4 nanoparticles 4. The injection hole 11 and its position provide conditions for the thermal conductor to exert its thermal conductivity and lubricity, and can take away the heat generated by the intense friction between the dynamic sealing ring 3 and the transmission shaft 1, thereby extending the service life of the dynamic sealing ring 3 and avoiding increasing the complexity of the rotary cutting device.

[0061] The technical effects of the present invention are further illustrated below by Examples 1-10 and Comparative Examples 1-4. In the following Examples and Comparative Examples:

[0062] The synthesis process of Fe3O4 nanoparticles adopts the chemical coprecipitation method, specifically: FeCl3·6H2O (7g, 0.52M) is dissolved in 50mL of distilled water, and FeSO4·7H2O (3.6g, 0.26M) is dissolved in 50mL of distilled water; then the two solutions are mixed and stirred at a molar ratio of 2:1. After 15 minutes, the orange solution is heated at 60°C with a stirring speed of 450rpm. 50mL of NH4OH solution diluted with distilled water to 10% is slowly dripped into the solution, and the temperature is controlled at 60°C on a magnetic stirrer. Heat, stir at 450 rpm for 90 min, stop heating and stirring when the solution turns black; then take out the magnetic bar, place the obtained black suspension on a permanent magnet, separate the precipitate from the solution for a quick and efficient precipitation process, and after 15 minutes, separate the colorless solution using magnetic declination; then wash the precipitate with distilled water for 7 times until the NH4OH smell disappears, and wash repeatedly to reduce the amount of salt produced by other reactions dissolved in the sample; finally, dry the washed solution at 80°C for 48 h on a hot plate and pound it into Fe3O4 nanoparticles using a mortar and pestle.

[0063] The method for PEG modification of Fe3O4 nanoparticles is as follows: 0.75g PEG is dissolved in 50mL distilled water using a magnetic stirrer, the heating temperature is controlled to be 60°C, the rotation speed is 450rpm, and the stirring is performed for 30min, and then 3g Fe3O4 dissolved in 50mL distilled water is added to the PEG solution and stirred again for 10min. In addition, the sample is deposited with a permanent magnet and then dried on a hot plate at 50°C for 24h. After drying, the sample is crushed into PEG-Fe3O4 nanoparticles.

[0064] The method for modifying Fe3O4 nanoparticles with PLGA is as follows: 1 g of PLGA is dissolved in 100 mL of DMSO (dimethyl sulfoxide) to obtain a 1% (w / v) PLGA solution. Then 5 g of Fe3O4 dissolved in 100 mL of distilled water is added to the PLGA solution, and the solution is centrifuged at 7000 rpm for 5 min under ultrasound assistance, washed with ethanol, and the sample is crushed into PLGA-Fe3O4 nanoparticles after drying.

[0065] The preparation method of the HPMC solution is as follows: slowly adding the target mass of HPMC into hot water of half the volume of the formula at 80° C. to dissolve (taking the mass concentration of 1% as an example, adding 1 g of HPMC into 50 mL of water), and stirring for 30-40 minutes using a mechanical stirrer to prevent agglomeration, at which time an HPMC suspension is formed; then the HPMC suspension is cooled to room temperature, and the remaining volume of water at 25° C. is added (taking the concentration of 1% as an example, adding 50 mL of water), and stirring is continued for 30-40 minutes using a stirrer until the HPMC is completely dissolved and the solution is uniform and free of bubbles, thereby obtaining an HPMC solution of the target concentration.

[0066] Under the condition of a rotation speed of 60000 rpm, the tests on the thermal conductivity and life of the dynamic seal ring of Examples 1-10 and Comparative Examples 1-4 are as follows:

[0067] Thermal conductivity effect: The thermal conductivity of the thermal conductive agent in different embodiments and comparative examples was tested using a thermal conductivity tester. The test results are as follows: Figure 4 As shown; the temperature of the handle shell at the dynamic seal ring position after running for 20 minutes is as follows Figure 5 As shown;

[0068] Dynamic seal life: The life of the dynamic seal is measured by a stopwatch. The test results are as follows: Figure 6 As shown; Taking the failure of the dynamic seal (i.e. water leakage) as the judgment standard, according to the actual service life of the existing dynamic seal, it can be preset that the dynamic seal cannot fail within 20 minutes, so the measurement time is set to 20 minutes to test the mass wear rate of the dynamic seal within this time. The measurement is performed using a precision electronic balance with an accuracy of 0.1 mg. The test results are shown in Figure 7 shown.

[0069] Example 1

[0070] This embodiment provides a method for extending the life of a dynamic seal ring of a medical peeling device by using magnetic particles and a medical peeling device, wherein the medical peeling device is used for the method for extending the life of a dynamic seal ring of a medical peeling device by using magnetic particles, such as Figure 1-3 As shown, the medical rotary cutting device includes a transmission shaft 1, a bearing sleeve 2, a dynamic seal ring 3, a welding component 5, a drainage hose 6, a drainage cavity 7, a rotary cutting head 8, a gear 9, a motor 10, a glue injection hole 11 and a dynamic seal ring chamber 12, and the method includes the following steps:

[0071] A glue injection hole 11 is opened at the waste liquid inlet end of the bearing sleeve 2 in the rotary cutting device, one end of the glue injection hole 11 is connected to the dynamic seal ring chamber 12 of the dynamic seal ring 3 close to the waste liquid inlet, the glue injection holes 11 are evenly distributed along the rotation center of the bearing sleeve 2, the distance between the center of the glue injection hole 11 and the center of the bearing sleeve 2 is 0.8mm, the depth of the glue injection hole 11 is 0.8mm, the inner diameter is 0.15mm, and the number is 8;

[0072] PEG-Fe3O4 nanoparticles are added to a HPMC solution at 20°C, with a mass concentration of 1.5% and a viscosity of 5.5cp, and mechanically stirred for 20 minutes to obtain a solution containing HPMC-PEG-Fe3O4 nanoparticles 4, i.e., a thermal conductor, wherein the particle size of the Fe3O4 nanoparticles is 10-30nm, and the volume fraction of the Fe3O4 nanoparticles in the thermal conductor is 0.025%. The thermal conductor is injected into the injection hole 11 by a syringe to fill the injection hole 11 with the thermal conductor, and the bearing sleeve 2 is dried to remove most of the solvent, and placed at 70°C for curing for 1.6 hours, so that the HPMC-PEG-Fe3O4 nanoparticles 4 can be cured in the injection hole 11 of the bearing sleeve 2;

[0073] Taking advantage of the fact that HPMC-PEG-Fe3O4 nanoparticles 4 are soluble in physiological saline or heparin saline, 25°C physiological saline is injected into the drainage chamber 7 to remove the air in the bearing sleeve 2 and the drainage chamber 7. During this process, the saline enters the injection hole 11 along the gap between the bearing sleeve 2 and the transmission shaft 1 and releases the HPMC-PEG-Fe3O4 nanoparticles 4. Since one end of the injection hole 11 is connected to the dynamic sealing ring chamber 12, the HPMC-PEG-Fe3O4 nanoparticles 4 enter the vicinity of the dynamic sealing ring chamber 12. When the rotary cutting device is started, the HPMC-PEG-Fe3O4 nanoparticles 4 are sucked by the negative pressure. The C-PEG-Fe3O4 nanoparticles 4 enter the dynamic sealing ring chamber 12, and absorb the heat of the dynamic sealing ring 3 by using their own thermal conductivity. The HPMC-PEG-Fe3O4 nanoparticles 4 that have not been completely dissolved continue to dissolve along with the waste liquid sucked up, so that during the operation of the rotary cutting device, there are always HPMC-PEG-Fe3O4 nanoparticles 4 in the drainage chamber 7. The HPMC-PEG-Fe3O4 nanoparticles 4 that have undergone heat exchange are discharged from the rotary cutting device along with the waste liquid through the drainage hose 6 of the drainage chamber 7, thereby continuously taking away heat and preventing the temperature of the dynamic sealing ring chamber 12 from being too high.

[0074] Example 2

[0075] This embodiment provides a method for extending the service life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The method is different from that of Embodiment 1 only in that the volume fraction of Fe3O4 nanoparticles in the thermal conductive agent is 0.016%.

[0076] Example 3

[0077] This embodiment provides a method for extending the service life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The method is different from that of Embodiment 1 only in that the volume fraction of Fe3O4 nanoparticles in the thermal conductive agent is 0.01%.

[0078] like Figure 4-7As shown in the data of Examples 1-3 and Comparative Example 1, when the volume fraction of PEG-modified Fe3O4 nanoparticles is 0.01%-0.025%, the thermal conductivity reaches 0.697 W·m -1 ·K -1 As above, the service life of the dynamic sealing ring reaches more than 35.7 min, the wear rate of the dynamic sealing ring reaches less than 0.586% after 20 min, and the temperature of the handle shell at the position of the dynamic sealing ring reaches less than 29.3°C after 20 min of operation. The thermal conductivity coefficients of Examples 1-3 are significantly increased compared with Comparative Example 1 (the volume fraction of Fe3O4 nanoparticles is 0), and the thermal conductivity effect is stable, and the service life of the dynamic sealing ring is significantly improved.

[0079] Example 4

[0080] This embodiment provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The method is different from that of Embodiment 1 in that the depth of the injection hole 11 is 0.64 mm, the inner diameter is 0.15 mm, and the number is 10. The total volume of the injection hole is kept unchanged.

[0081] Example 5

[0082] This embodiment provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The method is different from that of Embodiment 1 in that the depth of the injection hole 11 is 0.8 mm, the inner diameter is 0.15 mm, and the number is 12. The total volume of the injection hole is kept unchanged.

[0083] Example 6

[0084] This embodiment provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The method is different from that of Embodiment 1 in that the depth of the injection hole 11 is 1 mm, the inner diameter is 0.134 mm, and the number is 8. The total volume of the injection hole is kept unchanged.

[0085] like Figure 5-7 As shown, by comparing Examples 4-6 with Example 1, it can be seen that the life of the dynamic seal in Example 6 is lower than that of Examples 4-5 and Example 1, and the wear rate of the dynamic seal and the temperature of the handle shell at the dynamic seal at 20 minutes are higher than those of Examples 4-5 and Example 1. This shows that when the total volume in the injection hole remains unchanged, the size and number of the injection holes do not affect the release of PEG-modified Fe3O4 nanoparticles from HPMC, while the depth of the injection holes affects the release of PEG-modified Fe3O4 nanoparticles from HPMC, resulting in a decrease in thermal conductivity per unit time.

[0086] Example 7

[0087] This embodiment provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The method is different from that of Embodiment 1 only in that the Fe3O4 nanoparticles are modified by PLGA.

[0088] like Figure 4-7 As shown, from the comparison between Example 7 and Example 1, it can be seen that the thermal conductivity, life of the dynamic seal ring and wear rate of the dynamic seal ring of Example 7 are basically unchanged compared with those of Example 1, indicating that when the modifier of the Fe3O4 nanoparticles is changed from PEG to PLGA, its thermal conductivity efficiency does not change significantly, and the life of the dynamic seal ring is still good.

[0089] Example 8

[0090] This embodiment provides a method for extending the life of a dynamic sealing ring of a medical rotary cutting device by using magnetic particles. The only difference compared with Embodiment 1 is that the strength of the external magnetic field is 600 Gs, and the direction is from the distal end to the proximal end.

[0091] Example 9

[0092] This embodiment provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The only difference compared with Embodiment 2 is that the strength of the external magnetic field is 900 Gs, and the direction is from the distal end to the proximal end.

[0093] Example 10

[0094] This embodiment provides a method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles. The only difference compared with Embodiment 3 is that the strength of the external magnetic field is 1200 Gs, and the direction is from the distal end to the proximal end.

[0095] The simulation test was carried out for about 30 minutes using the methods provided in the above Examples 1-7 and Examples 8-10. The results are as follows: Figure 4-7 As shown, from the experimental results, it can be seen that the thermal conductivity and the life of the dynamic sealing ring in Examples 8-10 are significantly higher than those in Examples 1-7, and the wear rate of the dynamic sealing ring and the temperature of the handle shell at the dynamic sealing ring at 20 minutes are significantly lower than those in Examples 1-7, indicating that when an external magnetic field is applied, the magnetic Fe3O4 nanoparticles maintain a directional flow in the dynamic sealing ring chamber, thereby reducing the loss of effective ingredients of the thermal conductor, and the Fe3O4 nanoparticles are distributed in a chain shape under the magnetic field, which enhances the thermal conductivity of the Fe3O4 nanoparticles and improves the thermal conductivity efficiency, which is ultimately reflected in a longer retention of the thermal conductivity effect, and the thermal conductivity effect increases with the increase of the external magnetic field strength.

[0096] Comparative Example 1

[0097] This comparative example provides a method for extending the life of a dynamic sealing ring of a medical rotary cutting device by using magnetic particles. The only difference compared with Example 1 is that Fe3O4 nanoparticles are not added to the thermal conductive agent.

[0098] Comparative Example 2

[0099] This comparative example provides a rotary cutting device, which is different from Example 1 only in that the bearing sleeve is not provided with a glue injection hole, and the thermal conductive agent with an equal volume fraction is coated on the wall of the bearing sleeve by coating.

[0100] Comparative Example 3

[0101] This comparative example provides a rotary cutting device, which is different from Example 2 only in that the bearing sleeve is not provided with a glue injection hole, and an equal volume fraction of a thermal conductive agent is coated on the wall of the bearing sleeve by coating.

[0102] Comparative Example 4

[0103] This comparative example provides a rotary cutting device, which is different from Example 3 only in that the bearing sleeve is not provided with a glue injection hole, and an equal volume fraction of a thermal conductive agent is coated on the wall of the bearing sleeve by coating.

[0104] like Figure 5-7 As shown, by comparing Comparative Example 2 with Example 1, Comparative Example 3 with Example 2, and Comparative Example 4 with Example 3, it can be seen that the handle shell temperature at the dynamic sealing ring and the wear rate of the dynamic sealing ring when the embodiment is running for 20 minutes are lower than those of the comparative example, and the life of the dynamic sealing ring is significantly higher than that of the comparative example, indicating that when the thermal conductor is set by coating, the thermal conductor is lost faster, which leads to a greatly shortened thermal conductivity maintenance time, an increased wear rate of the dynamic sealing ring, and a reduced life, which cannot meet actual needs.

[0105] In summary, the method and medical rotary cutting device of the present invention can effectively improve the heat conduction efficiency, reduce the heating problem in the working area of ​​the dynamic sealing ring, and extend the service life of the dynamic sealing ring at high speed.

[0106] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for extending the life of a dynamic seal ring of a medical rotary cutting device by using magnetic particles, characterized in that: The method comprises: A glue injection hole is provided at the waste liquid inlet end of the bearing sleeve in the rotary cutting device, and one end of the glue injection hole is connected to the chamber of the dynamic sealing ring close to the waste liquid inlet; Injecting a thermal conductive agent into the glue injection hole, and curing the thermal conductive agent so that the thermal conductive agent is cured in the glue injection hole; The thermal conductive agent comprises magnetic particles, and the magnetic particles are dissolved in physiological saline or heparin saline.

2. The method according to claim 1, characterized in that The method further comprises controlling the movement of magnetic particles in the thermal conductive agent to the dynamic seal ring chamber by applying an external magnetic field.

3. The method according to claim 1, characterized in that The glue injection holes are evenly distributed along the rotation center of the bearing sleeve; Preferably, the depth of the glue injection hole is 0.5-1 mm; Preferably, the inner diameter of the glue injection hole is 0.1-0.3 mm.

4. The method according to claim 1, characterized in that: The magnetic particles include Fe3O4 nanoparticles.

5. The method according to claim 4, characterized in that The particle size of the Fe3O4 nanoparticles is 10-30nm.

6. The method according to claim 4, characterized in that The surfaces of the Fe3O4 nanoparticles are sequentially modified with a coating layer and a controlled release layer.

7. The method according to claim 6, characterized in that The material of the coating layer includes polyethylene glycol or polylactic acid-glycolic acid copolymer; Preferably, the material of the controlled release layer includes hydroxypropyl methylcellulose; Preferably, the thermal conductive agent is: adding polyethylene glycol-modified Fe3O4 nanoparticles to a hydroxypropyl methylcellulose solution to disperse the obtained HPMC-PEG-Fe3O4 nanoparticle solution; Preferably, the volume fraction of Fe3O4 nanoparticles in the thermal conductor is 0.01-0.025%.

8. The method according to claim 1, characterized in that The curing temperature is 60-80°C.

9. A medical rotary cutting device, characterized in that: The medical peeling device is used for the method for extending the life of the dynamic sealing ring of the medical peeling device by using magnetic particles as described in any one of claims 1 to 8; The medical rotary cutting device comprises a bearing sleeve and a drainage cavity; The end face of the bearing sleeve close to the waste liquid inlet is arranged inside the drainage cavity and a glue injection hole is provided on the end face, one end of the glue injection hole is connected to the chamber of the dynamic sealing ring close to the waste liquid inlet; the dynamic sealing ring is arranged between the bearing sleeve and the transmission shaft, and the transmission shaft passes through the dynamic sealing ring.

10. The medical rotary cutting device according to claim 9, characterized in that: The medical rotary cutting device also includes a driving mechanism and a rotary cutting mechanism; The driving structure includes a motor, and the motor drives a transmission shaft through gears; The rotary cutting mechanism comprises a rotary cutting cutter head, and the rotary cutting cutter head is connected to the transmission shaft in the drainage cavity through a welding component, and a drainage hose is arranged in the drainage cavity.

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