Black antibacterial coating for outer surface of clip applier, preparation method of black antibacterial coating and clip applier containing black antibacterial coating

Abstract

The invention relates to the technical field of medical instruments, in particular to a black antibacterial coating for the outer surface of a clip applier, a preparation method of the black antibacterial coating and the clip applier comprising the black antibacterial coating, and the black antibacterial coating comprises a black anodic oxidation layer and a controllable sealing layer which are sequentially arranged on the surface of a base material from inside to outside; the thickness of the black anodic oxidation layer is 0.5-1 [mu] m; the thickness of the controllable sealing layer is 0.01 to 0.2 [mu] m; the black anodic oxidation layer contains antibacterial metal ions, the controllable sealing layer is of a porous silane-chitosan sealing structure, and the porous structure allows the antibacterial metal ions to be gradually released; and the pore diameter and the porosity can be dynamically adjusted according to the change of the pH value, so that the release rate of the antibacterial metal ions is adaptively controlled. Through the synergistic effect of the black anodic oxidation layer and the controllable porous silane-chitosan composite sealing layer, a porous silane structure is combined to provide a controllable channel for release of antibacterial metal ions, and the intelligent release function of the coating in different environments is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a black antibacterial coating for the outer surface of a clip applier and a preparation method thereof, as well as a clip applier containing the coating. Background Art

[0002] In modern surgery, clip appliers are important tools for ligating blood vessels or other tubular tissue structures and are widely used in various complex surgical operations. Clip appliers are usually pre-assembled with ligation clips, and the structural design is relatively complex, especially the jaws at the working end need to bear the pushing, transfer and closing operations of the ligation clip. These complex mechanical actions determine that the clip applier must have high precision and reliability to ensure that the ligation clip can successfully complete the ligation of blood vessels or tissues and avoid bleeding or other surgical risks.

[0003] The working end of the clip applier is usually made of stainless steel, such as 304, 316L or 420 stainless steel, to ensure that the instrument has sufficient strength and corrosion resistance. However, the reflectivity of the stainless steel surface may become an interference factor under the surgical light, especially in laparoscopic surgery, where strong light reflections will affect the surgeon's field of vision and increase the difficulty of surgical operations. Therefore, many clip appliers need to be coated with a black coating on the stainless steel surface to reduce the reflection problem. However, the application of conventional black coatings on clip appliers still has multiple problems and technical difficulties.

[0004] (1) Complex structure leads to easy wear and peeling of the coating: The structure of the clip applier is relatively complex, especially the working end is responsible for pushing, transferring and closing the ligation clip during surgery, these actions will cause severe friction on the surface of the clip applier. Although the conventional black coating can play an anti-glare role on the stainless steel surface, due to the limited adhesion of the coating, it is easy to be worn during mechanical friction, especially in high-friction areas such as the jaws and pushing channels of the clip applier. The coating's wear resistance is insufficient, which may cause local coating peeling. The peeling of the coating not only affects the function of the clip applier, but also may produce tiny coating debris. If these debris remain in the surgical site, they may cause inflammatory reactions and even cause postoperative complications. In severe cases, they may affect the patient's recovery process.

[0005] (2) Lack of antibacterial function increases the risk of infection: There is a potential risk of infection during surgery. The clip applier is not an anatomical tool. It is mostly used to ligate corresponding blood vessels and tubular tissues in open surgery / laparoscopic surgery. The frequency of use is low. Therefore, traditional black coatings can effectively reduce the reflection problem, but basically have no antibacterial properties. This means that when the clip applier is operated in the body, the risk of infection may increase due to the attachment of microorganisms to the surface of the coating. In particular, microbial infection at the surgical site may lead to postoperative wound infection and even cause serious systemic infection. Therefore, the development of antibacterial coatings is crucial to improving the safety of clip appliers.

[0006] (3) Uniformity of coating and complex preparation process: Uniformly coating the complex surface of the clip applier is a technical difficulty in itself, especially in the push and close parts of the special-shaped structure. The coating is often difficult to cover evenly. The uneven thickness of the coating may lead to insufficient local wear resistance, which in turn causes the coating to fall off during use. In addition, the preparation process of some high-performance coatings is relatively complicated and may require multiple coatings or special treatments, which not only increases the cost of the coating, but also makes the production of the clip applier more expensive.

[0007] Therefore, it is an urgent technical problem to uniformly coat the surface of the clip applier with a complex structure with a black coating and ensure its antibacterial performance and durability. The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0008] The first object of the present invention is to provide a black antibacterial coating for the outer surface of a clip applier to solve the problems of the clip applier during surgery due to the reflection of stainless steel, easy wear of the coating, and lack of antibacterial properties.

[0009] The above technical objectives of the present invention are achieved through the following technical solutions:

[0010] A black antibacterial coating, comprising a black anodized layer and a controllable sealing layer sequentially arranged on the surface of a substrate from the inside to the outside;

[0011] The substrate is 420 medical grade stainless steel, the thickness of the black anodized layer is 0.5-1 μm; the thickness of the controllable sealing layer is 0.01-0.2 μm;

[0012] The black anodized layer contains antibacterial metal ions, and the controllable closed layer is a porous silane-chitosan closed structure. The porous structure allows the antibacterial metal ions to be gradually released; and the pore size and porosity can be dynamically adjusted according to the change of pH value, thereby adaptively controlling the release rate of the antibacterial metal ions.

[0013] Anodizing is an electrochemical process that applies voltage to oxidize the surface of stainless steel, generating a dense oxide layer. Due to its nanoscale pore structure, carbon black can be embedded or the thickness and structure of the oxide layer can be adjusted to present a black appearance. Antibacterial metal ions are introduced during the anodizing process, and the microporous structure in the oxide layer allows these metal ions to be gradually released from the coating, providing a long-term antibacterial effect.

[0014] The controlled sealing layer not only controls the release of antimicrobial metal ions, but also improves the stability of the anodized layer, preventing it from being physically worn or chemically corroded during use. If the clip applier comes into contact with liquid or human tissue during surgery, the controlled sealing layer can provide additional protection to prevent the anodized layer from being weakened by external factors; it can also provide a matte, anti-glare effect.

[0015] In the controllable closed layer, the SiO2 network formed by the hydrolysis of silane under acidic conditions constructs a porous structure, providing a channel for the release of antimicrobial metal ions. Chitosan is a natural polymer with pH responsiveness. When in contact with an acidic environment (such as blood), chitosan will swell and fill the micropores, reducing the release rate of antimicrobial metal ions. In the absence of liquid or normal conditions, chitosan remains relatively non-swelling and the micropores remain open, allowing the normal release of antimicrobial metal ions, thereby effectively maintaining the antimicrobial ability of the coating without affecting the normal function of the clip applicator.

[0016] Preferably, the pore size of the porous silane-chitosan closed structure is between 1 and 10 nm, and the porosity is controlled at 10% to 30%; the depth of the pores is 10% to 80% of the thickness of the controllable closed layer.

[0017] During abdominal surgery, the pH value will be affected by the local tissue fluid or lesions at the surgical site, especially at the infected site, where the pH is slightly acidic. When the clamp head of the clip applier gradually approaches the blood vessels or other tubular tissues, the chitosan expands under the influence of the acidic environment, and the release rate of metal ions slows down, thereby avoiding affecting the normal function of the clip applier. When the environment returns to normal, the pore size increases, and the metal ion release rate increases, ensuring that the clip applier remains sterile when placed normally. Through the synergistic effect of the black anodized layer and the controllable porous silane-chitosan composite sealing layer, the coating of the present invention can provide long-term antibacterial effects, as well as pH responsiveness and mechanical stability. The dynamic regulation of the entire system mainly depends on the pH response characteristics of chitosan, combined with the porous silane structure to provide a controllable channel for the release of antibacterial metal ions, thereby realizing the intelligent release function of the coating under different environments.

[0018] In the present invention, porous silane and chitosan form a composite solution for sealing the anodized layer, wherein the amount of chitosan is limited to 30% to 50% of the silane solution to avoid swelling of the coating in a wet environment due to excessive dosage, to avoid excessive stickiness of the coating surface, to ensure smooth use of the clip applier, and to adapt to the stable delivery of millimeter-level ligation clips.

[0019] A second object of the present invention is to provide a method for preparing a black antimicrobial coating that can achieve uniform coverage on the complex surface structure of the clip applier, particularly at the end of the clip applier and the push-to-close area, where the coating has consistency.

[0020] The above technical objectives of the present invention are achieved through the following technical solutions:

[0021] A method for preparing a black antibacterial coating comprises the following steps:

[0022] S1: The surface of the substrate is ultrasonically cleaned multiple times and passivation pretreatment is performed; the present invention removes oxides on the surface of the stainless steel by pickling, and then effectively removes the residues by alkaline washing and ultrapure water washing, which can significantly improve the adhesion, corrosion resistance and stability of the coating during the anodizing process.

[0023] Preferably, in S1, medical grade ultrapure water and isopropyl alcohol are used for multiple cleaning to ensure that the surface is free of oil, dust and organic residues; the surface oxide layer is removed by acid and alkaline washing, and then the substrate is thoroughly rinsed and dried with ultrapure water to ensure that there is no residual moisture on the surface of the substrate.

[0024] Furthermore, in S1, the pickling is to immerse in 20% HNO3 for 15 to 30 minutes, keep the solution temperature at 25 to 30°C, form a passivation film, enhance the adhesion and corrosion resistance of the coating, and then rinse thoroughly with ultrapure water and dry; the alkaline washing is a post-pickling treatment, and the dried substrate after pickling is completely immersed in a 5% to 10% NaOH solution, keep the solution temperature at 25 to 40°C, soak for 10 to 20 minutes, and then rinse again with ultrapure water.

[0025] S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and an inert electrode as a cathode, applying direct current for anodic oxidation, controlling the voltage to be between 10 and 30 V, and the current density to be between 0.5 and 1 A / dm 2, the temperature is between 15 and 25°C to ensure the uniform growth and color consistency of the oxide film; anodizing is an electrochemical oxidation process. Under the action of the electric field, components such as iron and chromium on the metal substrate are oxidized to form a dense oxide layer. Since the oxidation process generates a microporous structure at the nanoscale, these holes can embed carbon black to appear black. In the present invention, antibacterial metal ions such as silver nitrate or silver chloride are added to the anodizing solution. During the growth of the oxide layer, these ions are embedded in the micropores. The microporous structure allows the antibacterial ions to be slowly released to maintain a long-term antibacterial effect.

[0026] Preferably, in S2, the anodizing solution comprises the following components in parts by weight:

[0027] Film former: 10-20 parts; Oxidation accelerator: 0.5-2 parts; Antibacterial agent: 0.01-0.05 parts; Carbon black: 0.1-0.5 parts; Water: 65-80 parts;

[0028] Among them, the film-forming agent is concentrated sulfuric acid with a concentration of 15% to 20%, or phosphoric acid with a concentration of 10% to 15%; concentrated sulfuric acid or phosphoric acid can react with the metal surface to form a dense oxide film, thereby increasing the hardness and corrosion resistance of the coating; sulfuric acid or phosphoric acid with a moderate concentration can effectively control the formation rate and quality of the oxide film, thereby ensuring a uniform and stable coating.

[0029] The oxidation promoter is acetic acid or nitric acid; the concentration of the oxidation promoter in the anodizing solution is 0.1% to 1%; acetic acid or nitric acid can provide additional hydrogen ions or oxidizing ions in the anodizing solution to promote the anodizing reaction, and can also adjust the acidity and alkalinity of the anodizing solution to optimize the growth rate and uniformity of the oxide film.

[0030] The antibacterial agent is silver nitrate or silver chloride; the antibacterial agent is introduced into the anodizing solution, the main purpose of which is to integrate the antibacterial property into the final coating; silver nitrate or silver chloride can release silver ions, has a broad-spectrum antibacterial activity, and effectively inhibits the growth of microorganisms, thereby enabling the coating to have long-term antibacterial protection capabilities.

[0031] Carbon black is added to the anodizing solution. Its main function is to give the coating a black or dark appearance. It can improve the visual appearance of the coating without affecting the function of the coating and avoid reflections that affect surgical operations.

[0032] S3: Controllably seal the black anodized layer obtained in step S2 to obtain the black antibacterial coating.

[0033] Preferably, in S3, the preparation of the controllable sealing layer comprises the following steps:

[0034] S31: dissolving chitosan and hydrolyzing and polymerizing silane under acidic conditions, respectively, gradually adding the chitosan solution to the silane solution and stirring to mix evenly; adding a surfactant and mixing evenly, gradually and slowly adjusting the pH value of the mixed solution to 6-7 under stirring to control the uniform dispersion of silane and chitosan, and obtaining a silane-chitosan composite solution;

[0035] S32: slowly immerse the anodized substrate into the silane-chitosan composite solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 5 to 10 minutes to allow the silane and chitosan to gradually polymerize on the surface;

[0036] S33: taking out the substrate from the solution, placing it in an environment of 50 to 60° C. for curing for 15 to 30 minutes to form a stable porous silane-chitosan closed structure; the curing process can better crosslink and harden the silane and chitosan to form a durable and stable closed layer;

[0037] S34: Rinse the sealed substrate, clean it with anhydrous ethanol or ultrapure water to remove unreacted silane and dry it; ensure the purity and smoothness of the surface of the sealing layer, reduce the impact of residues, and improve the overall quality and performance of the coating.

[0038] Preferably, in step S31, dissolving chitosan and hydrolyzing and polymerizing silane are respectively performed under acidic conditions, and gradually adding the chitosan solution to the silane solution and stirring and mixing them uniformly means:

[0039] Tetraethoxysilane with a concentration of 0.1% to 0.5% by volume is diluted with anhydrous ethanol at a volume ratio of 1:9, deionized water of 0.1% by volume of the solution is added for hydrolysis reaction, and acetic acid is used to adjust the pH value of the solution to 4 to 5 to promote the polymerization of silane; 0.1% to 0.2% chitosan is dissolved in 0.5% to 1% acetic acid solution to prepare an acidic solution of chitosan; the chitosan solution is gradually added to the silane solution at a mass ratio of 1:2 to 3, and stirred to ensure that the two are evenly mixed.

[0040] Preferably, the surfactant is polyvinyl alcohol or polyoxyethylene, and the dosage of the surfactant is 0.05% to 0.1%. The above materials are all purchased from Aladdin or Merck.

[0041] The third object of the present invention is to provide a clip applier having a black antibacterial coating, which improves the performance and safety of the clip applier during surgery and meets the high standards required for modern surgical instruments.

[0042] The above technical objectives of the present invention are achieved through the following technical solutions:

[0043] A clip applier with a black antibacterial coating, comprising a handle and a working area, characterized in that the working area of ​​the clip applier is surface treated with the black antibacterial coating obtained by the method according to any one of claims 4 to 9, and the black antibacterial coating at least covers a range of 10 cm from the end of the clip applier toward the handle. Specifically, the range of 10 cm, 15 cm, 20 cm, etc. from the end of the clip applier toward the handle can be set to cover, and the entire working area can also be set to be completely covered.

[0044] In summary, the present invention has the following beneficial effects:

[0045] The present invention effectively reduces the reflection phenomenon on the stainless steel surface by providing a black anodized layer on the 420 stainless steel substrate. The vision of the surgeon is significantly improved under the operating light, which helps to perform more precise operations, reduce visual interference, and improve surgical safety and efficiency. In addition, since the clip applier involves complex mechanical operations such as pushing and closing during surgery, the coating has good wear resistance and adhesion. It ensures that the coating is not easy to fall off during high-frequency mechanical operations, ensuring its long-term stability in complex surgical environments.

[0046] The antibacterial metal ions in the black antibacterial coating are embedded in the anodized layer and gradually released through the porous sealing layer. It can maintain a sterile state during normal placement to avoid instrument contamination. The chitosan-silane composite sealing layer has an intelligent control function, which can respond to the local tissue environment (such as pH changes) during surgery and dynamically adjust the pore size and the release rate of antibacterial ions. In an acidic environment, the chitosan structure expands and fills the pores, slowing down the release of antibacterial metal ions; in a neutral or alkaline environment, the chitosan becomes dense and increases the release of metal ions. This dynamic control mechanism can maintain the sterility of the instrument during storage according to actual needs, and will not affect the surgical operation due to the release of excess ions.

[0047] The black antibacterial coating prepared in the present invention is suitable for disposable medical devices such as clip applicators. The material is easy to obtain, the process is relatively simple, and it is economical. Compared with the traditional high-cost coating technology, this solution can reduce the manufacturing cost while ensuring the black antibacterial effect, making it suitable for large-scale production of disposable medical devices, meeting the dual needs of medical devices for economy and reliability. DETAILED DESCRIPTION

[0048] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a black antibacterial coating for the outer surface of a clip applier and a preparation method thereof, as well as a clip applier containing the coating, are described in detail as follows.

[0049] Example 1

[0050] A black antibacterial coating for the outer surface of a clip applier comprises a black anodized layer with a thickness of 0.6 μm and a controllable sealing layer with a thickness of 0.1 μm, which are sequentially arranged on the surface of a substrate (420 medical grade stainless steel) from the inside to the outside; the pore size of the controllable sealing layer is about 5 nm, and the porosity is controlled at 25%; the preparation method of the above black antibacterial coating comprises the following steps:

[0051] S1: Use medical grade ultrapure water and isopropyl alcohol to clean the substrate multiple times to ensure that there is no oil, dust and organic residue on the surface; then soak the substrate in 20% HNO3 for 25 minutes, keep the solution temperature at 25°C for pickling, and then rinse it thoroughly with ultrapure water and dry it; then completely soak the pickled and dried substrate in 5% NaOH solution, keep the solution temperature at 30°C, soak it for 15 minutes, and then rinse it again with ultrapure water and dry it to ensure that there is no residual moisture on the substrate surface.

[0052] S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and graphite as a cathode, applying direct current for anodic oxidation, controlling the voltage to be between 20V and the current density to be 1A / dm 2 , the temperature is 20℃, the time is 20min, to ensure the uniform growth and color consistency of the oxide film;

[0053] The anodizing solution includes the following components in parts by weight: 18 parts of 15% concentrated sulfuric acid; 1 part of acetic acid; 0.03 parts of silver chloride; 0.3 parts of carbon black; 71 parts of water;

[0054] S3: performing controllable sealing on the black anodized layer obtained in step S2 to obtain the black antibacterial coating, wherein the preparation of the controllable sealing layer comprises the following steps:

[0055] S31: Use tetraethoxysilane with a concentration of 0.1% by volume and dilute it with anhydrous ethanol at a volume ratio of 1:9, add 0.1% deionized water by volume of the solution for hydrolysis reaction, and use acetic acid to adjust the pH value of the solution to 4.5 to promote the polymerization of silane; dissolve 0.1% chitosan in 0.5% acetic acid solution to obtain an acidic solution of chitosan; gradually add the chitosan solution to the silane solution at a mass ratio of 1:2, and stir to ensure that the two are evenly mixed; add polyvinyl alcohol and mix evenly, with a dosage of 0.05%. Under stirring, gradually and slowly adjust the pH value of the mixed solution to 6.5 to obtain a silane-chitosan composite solution;

[0056] S32: Slowly immerse the anodized substrate into the silane-chitosan composite solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 7 minutes to allow the silane and chitosan to gradually polymerize on the surface;

[0057] S33: taking out the substrate from the solution and curing it in an environment of 50° C. for 20 min to form a stable porous silane-chitosan closed structure;

[0058] S34: The sealed substrate is rinsed, cleaned with anhydrous ethanol or ultrapure water to remove unreacted silane, and dried.

[0059] A clip applier with a black antibacterial coating comprises a handle and a working area. The working area of ​​the clip applier is surface treated with the black antibacterial coating prepared by the above method. The black antibacterial coating at least covers a range of 10 cm from the end of the clip applier toward the handle.

[0060] Example 2

[0061] A black antibacterial coating for the outer surface of a clip applier comprises a black anodized layer with a thickness of 0.7 μm and a controllable sealing layer with a thickness of 0.15 μm, which are sequentially arranged on the surface of a substrate (420 medical grade stainless steel) from the inside to the outside; the pore size of the controllable sealing layer is about 8 nm, and the porosity is controlled at 20%; the preparation method of the above black antibacterial coating comprises the following steps:

[0062] S1: Use medical grade ultrapure water and isopropyl alcohol to clean the substrate multiple times to ensure that there is no oil, dust and organic residue on the surface; then soak the substrate in 20% HNO3 for 30 minutes, keep the solution temperature at 30°C for pickling, and then rinse it thoroughly with ultrapure water and dry it; then completely soak the pickled and dried substrate in 8% NaOH solution, keep the solution temperature at 35°C, soak it for 10 minutes, and then rinse it again with ultrapure water and dry it to ensure that there is no residual moisture on the substrate surface.

[0063] S2: Place the pretreated substrate in anodizing solution, use the substrate as anode and lead plate as cathode, apply direct current for anodizing, control the voltage to be between 25V and the current density to be 0.7A / dm 2 , the temperature is 25℃, the time is 25min, to ensure the uniform growth and color consistency of the oxide film;

[0064] The anodizing solution includes the following components in parts by weight: 15 parts of 15% phosphoric acid; 0.5 parts of nitric acid; 0.05 parts of silver nitrate; 0.1 parts of carbon black; 70 parts of water;

[0065] S3: performing controllable sealing on the black anodized layer obtained in step S2 to obtain the black antibacterial coating, wherein the preparation of the controllable sealing layer comprises the following steps:

[0066] S31: Use tetraethoxysilane with a concentration of 0.5% by volume and dilute it with anhydrous ethanol at a volume ratio of 1:9, add 0.1% of the solution volume of deionized water for hydrolysis reaction, use acetic acid to adjust the pH value of the solution to 5 to promote the polymerization of silane; dissolve 0.5% chitosan in 1% acetic acid solution to obtain an acidic solution of chitosan; gradually add the chitosan solution to the silane solution at a mass ratio of 1:3, and stir to ensure that the two are evenly mixed; add polyethylene oxide and mix evenly, with a dosage of 0.1%. Under stirring, gradually and slowly adjust the pH value of the mixed solution to 7 to obtain a silane-chitosan composite solution;

[0067] S32: slowly immerse the anodized substrate into the silane-chitosan composite solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 8 minutes to allow the silane and chitosan to gradually polymerize on the surface;

[0068] S33: taking out the substrate from the solution and curing it in an environment of 55° C. for 30 min to form a stable porous silane-chitosan closed structure;

[0069] S34: The sealed substrate is rinsed, cleaned with anhydrous ethanol or ultrapure water to remove unreacted silane, and dried.

[0070] A clip applier containing a black antibacterial coating comprises a handle and a working area. The black antibacterial coating prepared by the above method is used to perform surface treatment on the working area of ​​the clip applier, and the black antibacterial coating covers the entire working area of ​​the clip applier.

[0071] Example 3

[0072] A black antibacterial coating for the outer surface of a clip applier comprises a black anodized layer with a thickness of 1 μm and a controllable sealing layer with a thickness of 0.2 μm, which are sequentially arranged on the surface of a substrate (420 medical grade stainless steel) from the inside to the outside; the pore size of the controllable sealing layer is about 8 nm, and the porosity is controlled at 30%; the preparation method of the above black antibacterial coating comprises the following steps:

[0073] S1: Use medical grade ultrapure water and isopropyl alcohol to clean the substrate multiple times to ensure that there is no oil, dust and organic residue on the surface; then soak the substrate in 20% HNO3 for 25 minutes, keep the solution temperature at 28°C for acid pickling, and then rinse it thoroughly with ultrapure water and dry it; then completely immerse the acid-washed and dried substrate in 10% NaOH solution, keep the solution temperature at 40°C, soak it for 10 minutes, and then rinse it again with ultrapure water and dry it to ensure that there is no residual moisture on the substrate surface.

[0074] S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and graphite as a cathode, applying direct current for anodic oxidation, controlling the voltage to be between 30V and the current density to be 0.8A / dm 2 , the temperature is 22℃, the time is 30min, to ensure the uniform growth and color consistency of the oxide film;

[0075] The anodizing solution includes the following components in parts by weight: 20 parts of 15% concentrated sulfuric acid; 2 parts of nitric acid; 0.04 parts of silver chloride; 0.2 parts of carbon black; and 68 parts of water.

[0076] S3: performing controllable sealing on the black anodized layer obtained in step S2 to obtain the black antibacterial coating, wherein the preparation of the controllable sealing layer comprises the following steps:

[0077] S31: Use tetraethoxysilane with a concentration of 0.3% by volume and dilute it with anhydrous ethanol at a volume ratio of 1:9, add 0.1% of the solution volume of deionized water for hydrolysis reaction, use acetic acid to adjust the pH value of the solution to 5 to promote the polymerization of silane; dissolve 0.2% chitosan in 0.5% acetic acid solution to obtain an acidic solution of chitosan; gradually add the chitosan solution to the silane solution at a mass ratio of 1:2, and stir to ensure that the two are evenly mixed; add polyvinyl alcohol and mix evenly, with a dosage of 0.1%. Under stirring, gradually and slowly adjust the pH value of the mixed solution to 6.7 to obtain a silane-chitosan composite solution;

[0078] S32: slowly immerse the anodized substrate into the silane-chitosan composite solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 5 minutes to allow the silane and chitosan to gradually polymerize on the surface;

[0079] S33: taking out the substrate from the solution and curing it in an environment of 60° C. for 15 min to form a stable porous silane-chitosan closed structure;

[0080] S34: The sealed substrate is rinsed, cleaned with anhydrous ethanol or ultrapure water to remove unreacted silane, and dried.

[0081] A clip applier containing a black antibacterial coating comprises a handle and a working area. The black antibacterial coating prepared by the above method is used to perform surface treatment on the working area of ​​the clip applier, and the black antibacterial coating covers the entire working area of ​​the clip applier.

[0082] Comparative Example 1

[0083] A black antibacterial coating for the outer surface of a clip applier comprises a black anodized layer with a thickness of 0.6 μm arranged on the surface of a substrate (420 medical grade stainless steel) from the inside to the outside; a method for preparing the black antibacterial coating comprises the following steps:

[0084] S1: Use medical grade ultrapure water and isopropyl alcohol to clean the substrate multiple times to ensure that there is no oil, dust and organic residue on the surface; then soak the substrate in 20% HNO3 for 25 minutes, keep the solution temperature at 25°C for pickling, and then rinse it thoroughly with ultrapure water and dry it; then completely soak the pickled and dried substrate in 5% NaOH solution, keep the solution temperature at 30°C, soak it for 15 minutes, and then rinse it again with ultrapure water and dry it to ensure that there is no residual moisture on the substrate surface.

[0085] S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and graphite as a cathode, applying direct current for anodic oxidation, controlling the voltage to be between 20V and the current density to be 1A / dm 2 , the temperature is 20° C., the time is 20 min, to ensure the uniform growth and color consistency of the oxide film; and the black antibacterial coating is obtained.

[0086] The anodizing solution includes the following components in parts by weight: 18 parts of 15% concentrated sulfuric acid; 1 part of acetic acid; 0.03 parts of silver chloride; 0.3 parts of carbon black; 71 parts of water;

[0087] A clip applier with a black antibacterial coating comprises a handle and a working area. The working area of ​​the clip applier is surface treated with the black antibacterial coating prepared by the above method. The black antibacterial coating at least covers a range of 10 cm from the end of the clip applier toward the handle.

[0088] Comparative Example 2

[0089] A black antibacterial coating for the outer surface of a clip applier comprises a black anodized layer with a thickness of 0.6 μm and a sealing layer with a thickness of 0.1 μm which are sequentially arranged on the surface of a substrate (420 medical grade stainless steel) from the inside to the outside; the pore size of the controllable sealing layer is about 5 nm, and the porosity is controlled at 25%; the preparation method of the above black antibacterial coating comprises the following steps:

[0090] S1: Use medical grade ultrapure water and isopropyl alcohol to clean the substrate multiple times to ensure that there is no oil, dust and organic residue on the surface; then soak the substrate in 20% HNO3 for 25 minutes, keep the solution temperature at 25°C for pickling, and then rinse it thoroughly with ultrapure water and dry it; then completely soak the pickled and dried substrate in 5% NaOH solution, keep the solution temperature at 30°C, soak it for 15 minutes, and then rinse it again with ultrapure water and dry it to ensure that there is no residual moisture on the substrate surface.

[0091] S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and graphite as a cathode, applying direct current for anodic oxidation, controlling the voltage to be between 20V and the current density to be 1A / dm 2 , the temperature is 20℃, the time is 20min, to ensure the uniform growth and color consistency of the oxide film;

[0092] The anodizing solution includes the following components in parts by weight: 18 parts of 15% concentrated sulfuric acid; 1 part of acetic acid; 0.03 parts of silver chloride; 0.3 parts of carbon black; 71 parts of water;

[0093] S3: performing silane sealing on the black anodized layer obtained in step S2 to obtain the black antibacterial coating, wherein the preparation of the silane sealing layer comprises the following steps:

[0094] S31: using tetraethoxysilane with a concentration of 0.1% by volume and diluting it with anhydrous ethanol at a volume ratio of 1:9, adding deionized water with a volume of 0.1% of the solution to carry out a hydrolysis reaction, using acetic acid to adjust the pH value of the solution to 4.5 to promote the polymerization of silane; gradually and slowly adjusting the pH value of the mixed solution to 6.5 under stirring to obtain a silane solution;

[0095] S32: Slowly immerse the anodized substrate into the silane solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 7 minutes to allow the silane to gradually polymerize on the surface;

[0096] S33: taking out the substrate from the solution, placing it in an environment of 50° C. for curing for 20 minutes to form a stable porous silane closed structure;

[0097] S34: The sealed substrate is rinsed, cleaned with anhydrous ethanol or ultrapure water to remove unreacted silane, and dried.

[0098] A clip applier with a black antibacterial coating comprises a handle and a working area. The working area of ​​the clip applier is surface treated with the black antibacterial coating prepared by the above method. The black antibacterial coating at least covers a range of 10 cm from the end of the clip applier toward the handle.

[0099] Comparative Example 3

[0100] A black antibacterial coating for the outer surface of a clip applier comprises a black anodized layer with a thickness of 0.6 μm, a silane sealing layer with a thickness of 0.05 μm and a chitosan layer with a thickness of 0.05 μm arranged on the surface of a substrate (420 medical grade stainless steel) from the inside to the outside; the pore size of the silane sealing layer is about 5 nm, and the porosity is controlled at 25%; the preparation method of the above black antibacterial coating comprises the following steps:

[0101] S1: Use medical grade ultrapure water and isopropyl alcohol to clean the substrate multiple times to ensure that there is no oil, dust and organic residue on the surface; then soak the substrate in 20% HNO3 for 25 minutes, keep the solution temperature at 25°C for pickling, and then rinse it thoroughly with ultrapure water and dry it; then completely soak the pickled and dried substrate in 5% NaOH solution, keep the solution temperature at 30°C, soak it for 15 minutes, and then rinse it again with ultrapure water and dry it to ensure that there is no residual moisture on the substrate surface.

[0102] S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and graphite as a cathode, applying direct current for anodic oxidation, controlling the voltage to be between 20V and the current density to be 1A / dm 2 , the temperature is 20℃, the time is 20min, to ensure the uniform growth and color consistency of the oxide film;

[0103] The anodizing solution includes the following components in parts by weight: 18 parts of 15% concentrated sulfuric acid; 1 part of acetic acid; 0.03 parts of silver chloride; 0.3 parts of carbon black; 71 parts of water;

[0104] S3: performing silane sealing on the black anodized layer obtained in step S2, and then depositing a chitosan layer on the silane sealing layer to obtain the black antibacterial coating.

[0105] The preparation of the silane sealing layer comprises the following steps:

[0106] S31: using tetraethoxysilane with a concentration of 0.1% by volume and diluting it with anhydrous ethanol at a volume ratio of 1:9, adding deionized water with a volume of 0.1% of the solution to carry out a hydrolysis reaction, using acetic acid to adjust the pH value of the solution to 4.5 to promote the polymerization of silane; gradually and slowly adjusting the pH value of the mixed solution to 6.5 under stirring to obtain a silane solution;

[0107] S32: Slowly immerse the anodized substrate into the silane solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 7 minutes to allow the silane to gradually polymerize on the surface;

[0108] S33: taking out the substrate from the solution, placing it in an environment of 50° C. for curing for 20 minutes to form a stable porous silane closed structure;

[0109] S34: The sealed substrate is rinsed, cleaned with anhydrous ethanol or ultrapure water to remove unreacted silane, and dried.

[0110] The preparation of the chitosan layer comprises the following steps:

[0111] S35: dissolving 0.1% chitosan in 0.5% acetic acid solution to obtain an acidic solution of chitosan; and gradually and slowly adjusting the pH value of the mixed solution to 6.5 under stirring to obtain a chitosan solution;

[0112] S36: slowly immersing the substrate with a porous silane sealing structure into the chitosan composite solution to ensure that the solution is evenly covered on the surface of the porous silane sealing layer; immersing for 7 minutes to allow the chitosan to gradually polymerize on the surface;

[0113] S37: taking out the substrate from the solution and curing it in an environment of 50°C for 20 minutes to form a stable chitosan response structure;

[0114] S38: Rinse the sealed substrate and dry it.

[0115] A clip applier with a black antibacterial coating comprises a handle and a working area. The working area of ​​the clip applier is surface treated with the black antibacterial coating prepared by the above method. The black antibacterial coating at least covers a range of 10 cm from the end of the clip applier toward the handle.

[0116] Performance Testing

[0117] Specifically, the corrosion resistance of the outer coating of the clip applier was tested by salt spray test (ASTM B117), the scratch resistance of the outer coating of the clip applier was tested by hardness test (ASTM D3363), and the inhibition zone test was conducted for 48 hours on Staphylococcus aureus / Escherichia coli. Then, the clip applier samples were immersed in simulated body fluids of pH 5.5 and pH 7.4 for 15 minutes respectively to test the release rate of antibacterial ions and the smoothness of pushing.

[0118]

[0119]

[0120] Examples 1 to 3 exhibit good comprehensive performance, and their corrosion resistance, antibacterial properties, and mechanical stability all meet medical standards. Among them, in terms of economy, Example 1 has better comprehensive performance and is suitable for application on the outside of disposable clip appliers. Example 2 performs best in terms of antibacterial properties and pH responsiveness and is suitable for complex medical environments. Example 3 has better stability under high mechanical stress and can also be used for high-frequency surgical instruments.

[0121] Comparative Example 1 does not have a sealing layer, which results in the inability to release the antibacterial agent for a long time, and the mechanical properties are also affected accordingly. In Comparative Example 2, chitosan is not added to the sealing layer, resulting in the inability to adjust the release rate adaptively, which may cause the local metal ion concentration to exceed the standard in a short time, affecting healing. In Comparative Example 3, a silane sealing layer and a chitosan layer are sequentially provided outside the anodized layer. Although a long-lasting antibacterial effect is achieved, the mechanical properties are also affected accordingly. Specifically, in an acidic environment, chitosan swells, causing the coating surface to become soft and sticky, hindering the smooth use of the clip applier.

[0122] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A black antibacterial coating for the outer surface of a clip applier, characterized in that: It includes a black anodized layer and a controllable sealing layer which are sequentially arranged on the surface of the substrate from the inside to the outside; The substrate is 420 medical grade stainless steel, the thickness of the black anodized layer is 0.5-1 μm; the thickness of the controllable sealing layer is 0.01-0.2 μm; The black anodized layer contains antibacterial metal ions, and the controllable closed layer is a porous silane-chitosan closed structure. The porous structure allows the antibacterial metal ions to be gradually released; and the pore size and porosity can be dynamically adjusted according to the change of pH value, thereby adaptively controlling the release rate of the antibacterial metal ions.

2. A black antibacterial coating for the outer surface of a clip applier according to claim 1, characterized in that: The pore size of the porous silane-chitosan closed structure is between 1 and 10 nm, and the porosity is controlled at 10% to 30%; the depth of the pores is 10% to 80% of the thickness of the controllable closed layer.

3. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 1, characterized in that: The steps are as follows: S1: ultrasonic cleaning of the substrate surface is performed multiple times and passivation pretreatment is performed; S2: placing the pretreated substrate in an anodic oxidation solution, using the substrate as an anode and an inert electrode as a cathode, applying direct current for anodic oxidation, controlling the voltage between 10 and 30 V, and the current density between 0.5 and 1 A / dm 2 , the temperature is between 15 and 25°C to ensure uniform growth and color consistency of the oxide film; S3: Controllably seal the black anodized layer obtained in step S2 to obtain the black antibacterial coating.

4. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 3, characterized in that: In S1, medical-grade ultrapure water and isopropyl alcohol are used for multiple cleanings to ensure that there is no oil, dust, or organic residue on the surface; the surface oxide layer is removed by acid and alkaline washing, and then the substrate is thoroughly rinsed and dried with ultrapure water to ensure that there is no residual moisture on the surface of the substrate.

5. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 4, characterized in that: In S1, the acid pickling is to immerse in 20% HNO3 for 15 to 30 minutes, keep the solution temperature at 25 to 30°C, form a passivation film, enhance the adhesion and corrosion resistance of the coating, and then rinse thoroughly with ultrapure water and dry; the alkaline washing is a post-acid washing treatment, and the dried substrate after acid washing is completely immersed in 5% to 10% NaOH solution, keep the solution temperature at 25 to 40°C, soak for 10 to 20 minutes, and then rinse again with ultrapure water.

6. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 3, characterized in that: In S2, the anodizing solution comprises the following components in parts by mass: Film-forming agent: 10-20 parts; Oxidation accelerator: 0.5-2 parts; Antibacterial agent: 0.01-0.05 parts; Carbon black: 0.1-0.5 parts; Water: 65~80 parts; Wherein, the film-forming agent is concentrated sulfuric acid with a concentration of 15% to 20%, or phosphoric acid with a concentration of 10% to 15%; The oxidation promoter is acetic acid or nitric acid; the concentration of the oxidation promoter in the anodizing solution is 0.1% to 1%; The antibacterial agent is silver nitrate or silver chloride.

7. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 3, characterized in that: In S3, the preparation of the controllable sealing layer comprises the following steps: S31: dissolving chitosan and hydrolyzing and polymerizing silane under acidic conditions, respectively, gradually adding the chitosan solution to the silane solution and stirring to mix evenly; adding a surfactant and mixing evenly, and gradually and slowly adjusting the pH value of the mixed solution to 6-7 under stirring to obtain a silane-chitosan composite solution; S32: Slowly immerse the anodized substrate into the silane-chitosan composite solution to ensure that the solution evenly covers the surface of the black anodized layer; soak for 5 to 10 minutes to allow the silane and chitosan to gradually polymerize on the surface; S33: taking out the substrate from the solution, and curing it in an environment of 50-60° C. for 15-30 min to form a stable porous silane-chitosan closed structure; S34: The sealed substrate is rinsed, cleaned with anhydrous ethanol or ultrapure water to remove unreacted silane, and dried.

8. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 7, characterized in that: In step S31, dissolving chitosan and hydrolyzing and polymerizing silane are respectively performed under acidic conditions, and gradually adding the chitosan solution to the silane solution and stirring and mixing them uniformly means: Tetraethoxysilane with a concentration of 0.1% to 0.5% by volume is diluted with anhydrous ethanol at a volume ratio of 1:9, and deionized water of 0.1% by volume of the solution is added for hydrolysis reaction. Acetic acid is used to adjust the pH value of the solution to 4 to 5 to promote the polymerization of silane; 0.1% to 0.2% chitosan is dissolved in 0.5% to 1% acetic acid solution to prepare an acidic solution of chitosan; the chitosan solution is gradually added to the silane solution at a mass ratio of 1:2 to 3, and stirred to ensure that the two are evenly mixed.

9. A method for preparing a black antibacterial coating on the outer surface of a clip applier according to claim 7, characterized in that: The surfactant is polyvinyl alcohol or polyoxyethylene, and the dosage of the surfactant is 0.05% to 0.1%.

10. A clip applier having a black antimicrobial coating, comprising a handle and a working area, characterized in that: The working area of ​​the clip applier is surface treated with the black antibacterial coating prepared by the method according to any one of claims 4 to 9, wherein the black antibacterial coating at least covers a range of 10 cm from the end of the clip applier toward the handle.

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