A black antibacterial coating for the outer surface of an applicator, a preparation method thereof, and an applicator containing the coating

Abstract

The present invention relates to the technical field of medical devices, and particularly to a black antibacterial coating for the outer surface of an applicator, a preparation method thereof, and an applicator with such a coating. The black antibacterial coating includes a black anodic oxidation layer and a controllable sealing layer that are sequentially arranged on the surface of a substrate from the inside out. The thickness of the black anodic oxidation layer is 0.5 to 1 μm; the thickness of the controllable sealing layer is 0.01 to 0.2 μm; the black anodic oxidation layer contains antibacterial metal ions, and the controllable sealing layer is a porous silane-chitosan sealing structure, and 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. Through the synergistic effect of the black anodic oxidation layer and the controllable porous silane-chitosan composite sealing layer, the present invention combines the porous silane structure to provide a controllable channel for the release of antibacterial metal ions, and realizes the intelligent release function of the coating in different environments.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a black antibacterial coating for the outer surface of an applicator, a preparation method thereof, and an applicator containing the coating. Background Art

[0002] In modern surgical operations, an applicator, as an important tool for ligating blood vessels or other tubular tissue structures, is widely used in various complex surgical procedures. The applicator is usually pre-assembled with ligation clips, and its structural design is relatively complex. In particular, the jaws at the working end need to undertake the operations of pushing, transferring, and closing the ligation clips. These complex mechanical actions determine that the applicator must have high precision and reliability to ensure that the ligation clip can successfully complete the ligation of blood vessels or tissues, avoiding bleeding or other surgical risks.

[0003] The working end of the applicator is usually made of stainless steel materials 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 lamp. Especially in endoscopic surgery, the strong light reflection will affect the vision of the surgeon and increase the difficulty of surgical operations. Therefore, many applicators need to be coated with a black coating on the stainless steel surface to reduce the reflection problem. However, there are still multiple problems and technical difficulties in the application of conventional black coatings on applicators.

[0004] (1) Complex structure leads to easy wear and peeling of the coating: The structure of the applicator is relatively complex. Especially, the working end undertakes actions such as pushing, transferring, and closing the ligation clip during the operation, and these actions will cause intense friction on the surface of the applicator. Although the conventional black coating can play a role in preventing reflection on the stainless steel surface, due to the limited adhesion of the coating, it is easily worn during the mechanical friction process. Especially in high-friction areas such as the jaws and pushing channels of the applicator, the wear resistance of the coating is insufficient, which may lead to local coating peeling. The peeling of the coating not only affects the function of the applicator but also may generate tiny coating debris. If these debris remain in the surgical site, they may cause an inflammatory reaction and even postoperative complications, and 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 the surgical process. The clip applier is not a dissection tool. It mostly realizes the ligation of corresponding blood vessels and tubular tissues in open surgery / laparoscopic surgery, and its usage frequency is relatively low. Therefore, traditional black coatings can mostly effectively reduce the reflection problem, but basically do not have 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 surface microorganisms on the coating. In particular, microbial infection at the surgical site may lead to postoperative wound infection and even cause serious systemic infections. Therefore, the development of antibacterial coatings is crucial for improving the safety of clip appliers.

[0006] (3)Coating uniformity and complex preparation process: Uniformly coating the coating on the complex surface of the clip applier itself is a technical difficulty. Especially in the pushing and closing parts with special-shaped structures, it is often difficult for the coating to cover evenly. Uneven coating thickness may lead to insufficient local wear resistance, and then cause the problem of coating peeling off during use. In addition, the preparation process of some high-performance coatings is relatively complex and may require multiple coatings or special treatments. This not only increases the cost of the coating but also makes the production of clip appliers more expensive.

[0007] Therefore, uniformly coating a black coating on the surface of the clip applier with a complex structure and ensuring its antibacterial properties and durability are technical problems that need to be solved urgently. The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention and should not be regarded as an admission or an indication in any form that this 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 stainless steel reflection, easy wear of the coating, lack of antibacterial properties, etc. during the surgical process.

[0009] The above technical object of the present invention is achieved through the following technical solutions:

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

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

[0012] The black anodic oxidation layer contains antibacterial metal ions, and the controllable sealing layer is a porous silane-chitosan sealing 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] Anodization is an electrochemical process in which a voltage is applied to oxidize the surface of stainless steel, generating a dense oxide layer. Due to its nano-scale pore structure, carbon black can be embedded or a black appearance can be presented by adjusting the thickness and structure of the oxide layer. During anodization, antibacterial metal ions are introduced, and the microporous structure in the oxide layer allows these metal ions to gradually be released from the coating, providing a long-term antibacterial effect.

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

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

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

[0017] During abdominal surgery, the pH value is affected by the local tissue fluid or lesions at the surgical site. Especially at the infected site, the pH is slightly acidic. When the jaws of the applicator gradually approach blood vessels or other tubular tissues, affected by the acidic environment, chitosan swells and the release rate of metal ions slows down, avoiding affecting the normal function of the applicator. When the environment returns to normal, the pore diameter increases and the release rate of metal ions increases, ensuring that the applicator remains sterile when placed normally. Through the synergistic effect of the black anodized layer and the controllable porous silane-chitosan composite sealing layer in the present invention, the coating can not only provide a long-term antibacterial effect but also possess pH responsiveness and mechanical stability. The dynamic regulation of the entire system mainly depends on the pH-responsive characteristics of chitosan, combined with the porous silane structure providing a controllable channel for the release of antibacterial metal ions, realizing the intelligent release function of the coating in different environments.

[0018] In the present invention, a porous silane and chitosan form a composite solution for sealing the anodic oxidation layer. Among them, the dosage of chitosan is limited to 30% - 50% of the silane solution, avoiding swelling of the coating in a humid environment due to excessive dosage, avoiding excessive stickiness on the surface of the coating, ensuring smooth use of the applicator, and thus adapting to the stable delivery of millimeter-sized ligating clips.

[0019] The second object of the present invention is to provide a method for preparing a black antibacterial coating, which can achieve uniform coverage on the complex surface structure of the applicator, especially at the end and the pushing and closing area of the applicator, and the coating has consistency.

[0020] The above technical object of the present invention is achieved through the following technical solutions:

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

[0022] S1: The surface of the substrate is ultrasonically cleaned multiple times and passivated pretreated; in the present invention, the oxide on the stainless steel surface is removed by pickling, and then the residue is effectively removed by alkali washing and ultrapure water rinsing, which can significantly improve the adhesion, corrosion resistance and stability of the coating during anodic oxidation.

[0023] Preferably, in S1, medical-grade ultrapure water and isopropanol are used for multiple cleanings to ensure that there is no oil stain, dust and organic matter residue on the surface; the surface oxide layer is removed by pickling and alkali washing treatment, and then 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 soak in 20% HNO3 for 15 - 30 min, keep the solution temperature at 25 - 30 °C to form a passivation film, enhance the adhesion and corrosion resistance of the coating, and then thoroughly rinse and dry with ultrapure water; the alkali washing is a post-treatment after pickling, completely soak the dried substrate after pickling in a 5% - 10% NaOH solution, keep the solution temperature at 25 - 40 °C, soak for 10 - 20 min, and then rinse again with ultrapure water.

[0025] S2: Place the pretreated substrate in an anodic oxidation solution, use the substrate as the anode and an inert electrode as the cathode, apply direct current for anodic oxidation, control the voltage between 10 - 30 V, and the current density is 0.5 - 1 A / dm 2, the temperature is 15 - 25°C to ensure uniform growth and color consistency of the oxide film; anodic oxidation is a process of electrochemical oxidation. Under the action of an 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 pores can embed carbon black to present a black color. In the present invention, antibacterial metal ions such as silver nitrate or silver chloride are added to the anodic oxidation solution. During the growth of the oxide layer, these ions are embedded into the micropores, and the microporous structure allows the slow release of antibacterial ions to maintain long-term antibacterial effects.

[0026] Preferably, in S2, the anodic oxidation solution comprises the following components in parts by mass:

[0027] Film-forming agent: 10 - 20 parts; Oxidation promoter: 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% - 20% or phosphoric acid with a concentration of 10% - 15%; concentrated sulfuric acid or phosphoric acid can react with the metal surface to form a dense oxide film, 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 to ensure the uniformity and stability of the coating.

[0029] The oxidation promoter is acetic acid or nitric acid; the concentration of the oxidation promoter in the anodic oxidation solution is 0.1% - 1%; acetic acid or nitric acid can provide additional hydrogen ions or oxidation ions in the anodic oxidation solution to promote the anodic oxidation reaction, and at the same time can adjust the acidity and alkalinity of the anodic oxidation 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 anodic oxidation solution, and the main purpose is to integrate antibacterial properties into the final coating; silver nitrate or silver chloride can release silver ions, having broad-spectrum antibacterial activity and effectively inhibiting the growth of microorganisms, so that the coating has long-term antibacterial protection ability.

[0031] Carbon black is added to the anodic oxidation solution, and its main function is to give the coating a black or dark appearance, which can improve the visual appearance of the coating without affecting the coating function and avoid the reflection affecting surgical operations.

[0032] S3: Perform controllable sealing on the black anodic oxidation layer prepared 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 applicator with a black antibacterial coating, comprising a handle and a working area. It is characterized in that the working area of the clip applicator is surface-treated with the black antibacterial coating prepared by the method according to any one of claims 4 to 9, and the black antibacterial coating covers at least a range of 10 cm from the end of the clip applicator towards the handle. Specifically, it can be set to cover ranges of 10 cm, 15 cm, 20 cm... from the end of the clip applicator towards the handle, or it can be set to cover the entire working area.

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

[0045] By providing a black anodized layer on the 420 stainless steel substrate, the present invention effectively reduces the reflection phenomenon on the surface of the stainless steel. It significantly improves the surgeon's field of vision under the surgical lamp, helps for more precise operations, reduces visual interference, and improves surgical safety and efficiency. And since the clip applicator 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 easily detached during high-frequency mechanical operations, guaranteeing its long-term stability in a complex surgical environment.

[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 and avoid instrument contamination. The chitosan-silane composite sealing layer has an intelligent regulation function and can respond to the local tissue environment (such as pH value changes) during the surgical process, dynamically adjusting the pore size and the release rate of antibacterial ions. In an acidic environment, the chitosan structure expands and fills the pore diameter, slowing down the release of antibacterial metal ions; while in a neutral or alkaline environment, the chitosan becomes dense, increasing the release of metal ions. This dynamic regulation mechanism can, according to actual needs, maintain the sterile state of the instrument during storage and will not affect surgical operations due to excessive ion release.

[0047] The black antibacterial coating prepared in the present invention is applicable to disposable medical devices such as clip applicators. Its materials are easy to obtain and the process is relatively simple, having economy. Compared with traditional high-cost coating technologies, this solution can reduce the manufacturing cost on the premise of ensuring the black antibacterial effect, making it applicable to disposable medical devices for large-scale production and meeting the dual requirements of economy and reliability for medical devices. Detailed implementation manners

[0048] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, a black antibacterial coating for the outer surface of a clip applicator, its preparation method, and a clip applicator containing the coating according to the present invention are described in detail below in terms of their specific implementation manners, features, and effects.

[0049] Example 1

[0050] A black antibacterial coating for the outer surface of an applicator, comprising 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 out; the pore diameter 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 includes the following operating 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 matter residue on the surface; then immerse the substrate in 20% HNO3 for 25 min, keep the solution temperature at 25 °C for pickling, and then thoroughly rinse and dry with ultrapure water; then completely immerse the pickled and dried substrate in a 5% NaOH solution, keep the solution temperature at 30 °C, soak for 15 min, and then rinse and dry with ultrapure water again to ensure that there is no residual moisture on the substrate surface.

[0052] S2: Place the pretreated substrate in the anodizing solution, use the substrate as the anode and graphite as the cathode, apply direct current for anodizing, control the voltage between 20 V, the current density is 1 A / dm 2 , the temperature is 20 °C, and the time is 20 min to ensure the uniform growth and color consistency of the oxide film;

[0053] Among them, the anodizing solution includes the following components in parts by mass: 18 parts of concentrated sulfuric acid with a concentration of 15%; 1 part of acetic acid; 0.03 part of silver chloride; 0.3 part of carbon black; 71 parts of water;

[0054] S3: Perform controllable sealing on the black anodized layer obtained in step S2 to obtain the black antibacterial coating. The preparation of the controllable sealing layer includes the following steps:

[0055] S31: Dilute tetraethoxysilane with a controlled volume percentage concentration of 0.1% and absolute ethanol in a volume ratio of 1:9, add 0.1% of deionized water by volume of the solution for hydrolysis reaction, and adjust the pH value of the solution to 4.5 with acetic acid to promote the polymerization of silane; dissolve 0.1% chitosan in a 0.5% acetic acid solution to prepare an acidic solution of chitosan; gradually add the chitosan solution to the silane solution in a mass ratio of 1:2, and stir to ensure uniform mixing of the two; add polyvinyl alcohol and mix evenly, with a dosage of 0.05%. Gradually and slowly adjust the pH value of the mixed solution to 6.5 under stirring to prepare a silane-chitosan composite solution;

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

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

[0058] S34: Rinse the sealed substrate and clean it with absolute ethanol or ultrapure water to remove the unreacted silane and dry it.

[0059] A clip applicator with a black antibacterial coating, including a handle and a working area. The working area of the clip applicator is surface-treated with the black antibacterial coating prepared by the above-mentioned method, and the black antibacterial coating covers at least a range of 10 cm from the end of the clip applicator towards the handle.

[0060] Example 2

[0061] A black antibacterial coating for the outer surface of a clip applicator, including a black anodic oxidation layer with a thickness of 0.7 μm and a controllable sealing layer with a thickness of 0.15 μm that are sequentially arranged on the surface of a substrate (420 medical-grade stainless steel) from the inside out; the pore diameter of the controllable sealing layer is about 8 nm, and the porosity is controlled at 20%; the preparation method of the above-mentioned black antibacterial coating includes the following operation steps:

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

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

[0064] Among them, the anodizing solution includes the following components in parts by mass: 15 parts of 15% concentration phosphoric acid; 0.5 part of nitric acid; 0.05 part of silver nitrate; 0.1 part of carbon black; 70 parts of water;

[0065] S3: Perform controllable sealing on the black anodic oxidation layer obtained in step S2 to obtain the black antibacterial coating. The preparation of the controllable sealing layer includes the following steps:

[0066] S31: Dilute tetraethoxysilane with a concentration by volume percentage of 0.5% and absolute ethanol at a volume ratio of 1:9, add deionized water accounting for 0.1% of the solution volume for hydrolysis reaction, and adjust the pH value of the solution to 5 with acetic acid to promote the polymerization of silane; dissolve 0.5% chitosan in 1% acetic acid solution to prepare 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 uniform mixing of the two; add polyethylene oxide and mix evenly, with the dosage being 0.1%. Gradually and slowly adjust the pH value of the mixed solution to 7 under stirring 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 min to allow silane and chitosan to gradually polymerize on the surface;

[0068] S33: Take out the substrate from the solution and place it in an environment at 55 °C for 30 min to form a stable porous silane-chitosan sealing structure;

[0069] S34: Rinse the sealed substrate and clean it with absolute ethanol or ultrapure water to remove unreacted silane and then dry it.

[0070] A clip applicator with a black antibacterial coating, including a handle and a working area, the working area of the clip applicator is surface-treated with the black antibacterial coating prepared by the above method, and the black antibacterial coating covers the entire working area of the clip applicator.

[0071] Example 3

[0072] A black antibacterial coating for the outer surface of a clip applicator, including a black anodized layer with a thickness of 1 μm and a controllable sealing layer with a thickness of 0.2 μm that are sequentially arranged on the surface of a substrate (420 medical-grade stainless steel) from the inside out; the pore diameter 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 includes the following operating steps:

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

[0074] S2: Place the pre-treated substrate in an anodizing solution. Using the substrate as the anode and graphite as the cathode, apply direct current for anodization. Control the voltage within 30V, the current density at 0.8 A / dm 2 , the temperature at 22 °C, and the time for 30 min to ensure uniform growth of the oxide film and color consistency;

[0075] Among them, the anodizing solution includes the following components in parts by mass: 20 parts of concentrated sulfuric acid with a concentration of 15%; 2 parts of nitric acid; 0.04 parts of silver chloride; 0.2 parts of carbon black; water: 68 parts;

[0076] S3: Conduct controllable sealing on the black anodized layer obtained in step S2 to obtain the black antibacterial coating. The preparation of the controllable sealing layer includes the following steps:

[0077] S31: Dilute tetraethoxysilane with a controlled concentration by volume percentage of 0.3% and absolute ethanol in a volume ratio of 1:9, add deionized water accounting for 0.1% of the solution volume for hydrolysis reaction, and adjust the pH value of the solution to 5 with acetic acid to promote the polymerization of silane; Dissolve 0.2% chitosan in a 0.5% acetic acid solution to prepare an acidic solution of chitosan; Gradually add the chitosan solution to the silane solution in a mass ratio of 1:2 and stir to ensure uniform mixing of the two; Add polyvinyl alcohol and mix evenly, with a dosage of 0.1%. Gradually and slowly adjust the pH value of the mixed solution to 6.7 under stirring to prepare a silane-chitosan composite solution;

[0078] S32: Slowly immerse the anodized substrate in the silane-chitosan composite solution to ensure that the solution evenly covers the surface of the black anodized layer; Soak for 5 min to allow silane and chitosan to gradually polymerize on the surface;

[0079] S33: Take out the substrate from the solution and cure it in an environment at 60 °C for 15 min to form a stable porous silane-chitosan sealing structure;

[0080] S34: Rinse the sealed substrate and clean it with absolute ethanol or ultrapure water to remove unreacted silane and dry it.

[0081] A clip applicator with a black antibacterial coating includes a handle and a working area. The working area of the clip applicator is surface-treated with the black antibacterial coating prepared by the above method, and the black antibacterial coating covers the entire working area of the clip applicator.

[0082] Comparative Example 1

[0083] A black antibacterial coating for the outer surface of an applicator, comprising a black anodized layer with a thickness of 0.6 μm sequentially arranged from the inside out on the surface of a substrate (420 medical-grade stainless steel); the preparation method of the above-mentioned black antibacterial coating includes the following operating steps:

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

[0085] S2: Place the pretreated substrate in an anodizing solution, use the substrate as the anode and graphite as the cathode, apply direct current for anodization, control the voltage between 20 V, the current density is 1 A / dm 2 , the temperature is 20 °C, and the time is 20 min to ensure the uniform growth of the oxide film and color consistency; obtain the above-mentioned black antibacterial coating.

[0086] Among them, the anodizing solution includes the following components in parts by mass: 18 parts of concentrated sulfuric acid with a concentration of 15%; 1 part of acetic acid; 0.03 parts of silver chloride; 0.3 parts of carbon black; 71 parts of water;

[0087] An applicator with a black antibacterial coating, comprising a handle and a working area, use the black antibacterial coating prepared by the above-mentioned method to perform surface treatment on the working area of the applicator, and the black antibacterial coating covers at least a range of 10 cm of the end of the applicator facing the handle.

[0088] Comparative Example 2

[0089] A black antibacterial coating for the outer surface of an applicator, comprising a black anodized layer with a thickness of 0.6 μm and a sealing layer with a thickness of 0.1 μm sequentially arranged from the inside out on the surface of a substrate (420 medical-grade stainless steel); the pore diameter of the controllable sealing layer is about 5 nm, and the porosity is controlled at 25%; the preparation method of the above-mentioned black antibacterial coating includes the following operating steps:

[0090] S1: Clean the substrate multiple times with medical - grade ultrapure water and isopropanol to ensure that there is no oil stain, dust, and organic matter residue on the surface. Then soak the substrate in 20% HNO3 for 25 min, keep the solution temperature at 25°C for pickling, and then rinse it thoroughly with ultrapure water and dry it. After that, completely soak the pickled and dried substrate in a 5% NaOH solution, keep the solution temperature at 30°C, soak for 15 min, 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: Place the pretreated substrate in an anodizing solution, use the substrate as the anode and graphite as the cathode, apply direct current for anodizing, control the voltage between 20V, the current density is 1A / dm 2 , the temperature is 20°C, and the time is 20 min to ensure the uniform growth and color consistency of the oxide film;

[0092] Among them, the anodizing solution includes the following components in parts by mass: 18 parts of concentrated sulfuric acid with a concentration of 15%; 1 part of acetic acid; 0.03 parts of silver chloride; 0.3 parts of carbon black; 71 parts of water;

[0093] S3: Perform silane sealing on the black anodic oxidation layer obtained in step S2 to obtain the black antibacterial coating. The preparation of the silane sealing layer includes the following steps:

[0094] S31: Dilute tetraethoxysilane with a controlled concentration - volume percentage of 0.1% and anhydrous ethanol at a volume ratio of 1:9, add 0.1% of deionized water by the volume of the solution for hydrolysis reaction, use acetic acid to adjust the pH value of the solution to 4.5 to promote the polymerization of silane. Gradually and slowly adjust the pH value of the mixed solution to 6.5 under stirring to obtain a silane solution;

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

[0096] S33: Take out the substrate from the solution and place it in an environment at 50°C for 20 min to cure to form a stable porous silane sealing structure;

[0097] S34: Rinse the sealed substrate, and clean it with anhydrous ethanol or ultrapure water to remove the unreacted silane and dry it.

[0098] A clip applicator with a black antibacterial coating includes a handle and a working area. Use the black antibacterial coating prepared by the above - mentioned method to perform surface treatment on the working area of the clip applicator. The black antibacterial coating covers at least the range of 10 cm of the end of the clip applicator facing the handle.

[0099] Comparative Example 3

[0100] A black antibacterial coating for the outer surface of an applicator, comprising 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, which are sequentially arranged on the surface of a substrate (420 medical-grade stainless steel) from the inside out; the pore diameter 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 includes the following operation steps:

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

[0102] S2: Place the pretreated substrate in an anodizing solution, use the substrate as the anode, use graphite as the cathode, apply direct current for anodizing, control the voltage between 20 V, the current density is 1 A / dm 2 , the temperature is 20 °C, and the time is 20 min to ensure the uniform growth and color consistency of the oxide film;

[0103] Among them, the anodizing solution includes the following components in parts by mass: 18 parts of concentrated sulfuric acid with a concentration of 15%; 1 part of acetic acid; 0.03 part of silver chloride; 0.3 part of carbon black; 71 parts of water;

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

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

[0106] S31: Dilute tetraethoxysilane with a controlled concentration by volume percentage of 0.1% and absolute ethanol in a volume ratio of 1:9, add deionized water with a volume of 0.1% of the solution volume for hydrolysis reaction, use acetic acid to adjust the pH value of the solution to 4.5 to promote the polymerization of silane; gradually and slowly adjust the pH value of the mixed solution to 6.5 under stirring to obtain a silane solution;

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

[0108] S33: Remove the substrate from the solution and place it in an environment at 50 °C for curing for 20 min to form a stable porous silane sealing structure;

[0109] S34: Rinse the sealed substrate and clean it with absolute ethanol or ultrapure water to remove the unreacted silane and then dry it.

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

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

[0112] S36: Slowly immerse the substrate with the formed porous silane sealing structure into the chitosan composite solution to ensure that the solution evenly covers the surface of the porous silane sealing layer; soak for 7 min to allow the chitosan to gradually polymerize on the surface;

[0113] S37: Remove the substrate from the solution and place it in an environment at 50 °C for curing for 20 min to form a stable chitosan-responsive structure;

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

[0115] A clip applicator with a black antibacterial coating includes a handle and a working area. The working area of the clip applicator is surface-treated with the black antibacterial coating prepared by the above method, and the black antibacterial coating covers at least a range of 10 cm from the end of the clip applicator towards the handle.

[0116] Performance testing

[0117] Specifically, the corrosion resistance of the outer coating of the clip applicator is tested by salt spray test (ASTM B117), the scratch resistance of the outer coating of the clip applicator is tested by hardness test (ASTM D3363), and the inhibition zone experiment is carried out for 48 h for Staphylococcus aureus / Escherichia coli. Then, the clip applicator samples are successively immersed in simulated body fluids with pH 5.5 and pH 7.4 for 15 min to test the release rate of antibacterial ions and the pushing smoothness.

[0118]

[0119]

[0120] Examples 1 to 3 exhibited good comprehensive performance, with corrosion resistance, antibacterial property, and mechanical stability all meeting medical standards. Among them, considering economy, Example 1 had relatively better comprehensive performance and was suitable for the application outside disposable clip appliers. Example 2 showed the best performance in antibacterial property and pH responsiveness and was suitable for complex medical environments. Example 3 had better stability under high mechanical stress and could also be applied to surgical instruments used frequently.

[0121] In Comparative Example 1, no sealing layer was provided, resulting in the inability of the antibacterial agent to be released for a long time and the corresponding impact on mechanical properties. In Comparative Example 2, chitosan was not added to the sealing layer, resulting in the inability to adjust the release rate adaptively, which might lead to excessive local metal ion concentration in a short time and affect healing. In Comparative Example 3, a silane sealing layer and a chitosan layer were sequentially provided outside the anodic oxidation layer. Although a lasting antibacterial effect was achieved, the mechanical properties were also affected accordingly. Specifically, in an acidic environment, chitosan swelled, causing the surface of the coating 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 by the above embodiments. What is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A black antibacterial coating for the outer surface of an applicator, characterized in that, It includes a black anodic oxidation layer and a controllable sealing layer which are sequentially arranged on the surface of the substrate from the inside out; The substrate is 420 medical-grade stainless steel, the thickness of the black anodic oxidation layer is 0.5 - 1 μm; the thickness of the controllable sealing layer is 0.01 - 0.2 μm; The black anodic oxidation layer contains antibacterial metal ions, and the controllable sealing layer is a porous silane-chitosan sealing structure. The SiO2 network formed by the hydrolysis of silane under acidic conditions with a pH value of 4 - 5 constructs a porous structure. The porous structure allows the gradual release of the antibacterial metal ions; and dynamically adjusts the pore size and porosity according to the change of pH value, thereby adaptively controlling the release rate of the antibacterial metal ions; The pore size of the porous silane-chitosan sealing structure is between 1 - 10 nm, and the porosity is controlled at 10% - 30%; the depth of the pores is 10% - 80% of the thickness of the controllable sealing layer. The porous silane-chitosan sealing structure is obtained by sealing the anodic oxidation layer with a composite solution of porous silane and chitosan. Among them, the dosage of chitosan is limited to 30% - 50% of the silane solution to avoid excessive viscosity on the surface of the coating.

2. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 1, characterized in that, It includes the following operation steps: S1: Perform ultrasonic cleaning on the surface of the substrate multiple times and carry out passivation pretreatment; S2: Place the pre-treated substrate in an anodizing solution, use the substrate as the anode and an inert electrode as the cathode, apply direct current for anodization, control the voltage between 10 and 30 V, and the current density is 0.5 to 1 A / dm 2 , and the temperature is between 15 and 25 °C to ensure uniform growth of the oxide film and color consistency; S3: Carry out controllable sealing on the black anodic oxidation layer obtained in step S2 to obtain the black antibacterial coating.

3. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 2, characterized in that, In S1, use medical-grade ultrapure water and isopropanol to clean multiple times to ensure that there is no oil stain, dust and organic matter residue on the surface; through pickling and alkali washing treatment, remove the surface oxide layer, and then thoroughly rinse and dry with ultrapure water to ensure that there is no residual moisture on the surface of the substrate.

4. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 3, characterized in that, In S1, the pickling is to soak in 20% HNO3 for 15 - 30 min, keep the solution temperature at 25 - 30 °C to form a passivation film, enhance the adhesion and corrosion resistance of the coating, and then thoroughly rinse and dry with ultrapure water; the alkali washing is a post-treatment after pickling. Immerse the substrate dried after pickling completely in a 5% - 10% NaOH solution, keep the solution temperature at 25 - 40 °C, soak for 10 - 20 min, and then rinse again with ultrapure water.

5. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 2, characterized in that, In S2, the anodic oxidation solution includes the following components in parts by mass: Film-forming agent: 10 - 20 parts; Oxidation promoter: 0.5 - 2 parts; Antibacterial agent: 0.01 - 0.05 parts; Carbon black: 0.1 - 0.5 parts; Water: 65 - 80 parts; Among them, the film-forming agent is concentrated sulfuric acid with a concentration of 15% - 20%, or phosphoric acid with a concentration of 10% - 15%; The oxidation promoter is acetic acid or nitric acid; the concentration of the oxidation promoter in the anodic oxidation solution is 0.1% - 1%; The antibacterial agent is silver nitrate or silver chloride.

6. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 2, characterized in that, In S3, the preparation of the controllable sealing layer includes the following steps: S31: Dissolve chitosan and hydrolyze and polymerize silane respectively under acidic conditions. Gradually add the chitosan solution to the silane solution and stir to mix evenly; add a surfactant and mix evenly. Gradually and slowly adjust 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 uniformly covers the surface of the black anodized layer; soak for 5 - 10 min to allow the silane and chitosan to gradually polymerize on the surface; S33: Take out the substrate from the solution and place it in an environment of 50 - 60 °C for curing for 15 - 30 min to form a stable porous silane-chitosan sealing structure; S34: Rinse the sealed substrate and clean it with absolute ethanol or ultrapure water to remove the unreacted silane and dry it.

7. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 6, characterized in that, In step S31, under acidic conditions, the dissolution of chitosan and the hydrolysis polymerization of silane are carried out respectively. Gradually adding the chitosan solution to the silane solution and stirring to mix evenly means: Dilute tetraethoxysilane with a concentration by volume percentage controlled at 0.1% - 0.5% and absolute ethanol in a volume ratio of 1:9, add deionized water accounting for 0.1% of the solution volume for hydrolysis reaction, use acetic acid to adjust the pH value of the solution to 4 - 5 to promote the polymerization of silane; dissolve 0.1% - 0.2% chitosan in 0.5% - 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 1:2 - 3 and stir to ensure uniform mixing of the two.

8. The preparation method of a black antibacterial coating for the outer surface of an applicator according to claim 6, characterized in that, The surfactant is polyvinyl alcohol or polyoxyethylene, and the dosage of the surfactant is 0.05% - 0.1%.

9. A clip applicator with a black antibacterial coating, comprising a handle and a working area, characterized in that, Use the method according to any one of claims 3 - 8 to perform surface treatment on the working area of the applicator to obtain a black antibacterial coating, and the black antibacterial coating covers at least a range of 10 cm of the end of the applicator facing the handle.

Images