An antibacterial coating for ePTFE implants, its preparation method and application

Abstract

This invention belongs to the field of medical implant surface modification technology, specifically disclosing an antibacterial coating for ePTFE implants, its preparation method, and its application. The method includes the following steps: plasma etching of ePTFE material, followed by immersion of the plasma-etched ePTFE material in a conductive organic polymer dispersion to form a conductive coating on the ePTFE material surface; using the ePTFE material with the conductive coating as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode to construct a three-electrode system; and performing an electropolymerization reaction in a working solution containing antibacterial active substances to form an antibacterial active substance layer on the outer layer of the ePTFE material. This invention features a simple and low-cost process, produces a uniform, stable, non-toxic, and environmentally friendly coating with extremely high antibacterial rate and biocompatibility.

Description

Technical Field

[0001] This invention belongs to the field of medical implant surface modification technology, specifically relating to an antibacterial coating for ePTFE implant surface, its preparation method, and its application. Background Technology

[0002] Expanded polytetrafluoroethylene (ePTFE), as a stable organic polymer material, is widely used in the field of medical implants due to its excellent biocompatibility, bioinertness, non-toxicity, and plasticity. However, its mesoporous structure makes it susceptible to bacterial colonization and implant-related infections, leading to patient complications and economic losses.

[0003] In related technologies, invention patent CN109529128A discloses an anti-infective coating and its preparation method, including the following steps: a) coating the surface of a medical polymer material with a photoinitiator to obtain a base material; b) placing the base material obtained in step a) in a mixed solution including an anti-adhesion monomer, a pH-responsive polymeric monomer, and polyethylene glycol diacrylate, and performing an ultraviolet crosslinking reaction to obtain a material with a gel coating on the surface; c) chemically loading the material with the gel coating obtained in step b) with antibiotics to obtain an anti-infective coating. The preparation method provided by this invention application uses specific processes and conditions to obtain an anti-infective coating; this anti-infective coating has dual functions of antibacterial adhesion and controlled antibiotic release bactericidal effect. While effectively reducing bacterial adhesion, it can achieve controlled and on-demand release of antibiotics, thereby solving the problems of poor antibacterial effect persistence caused by excessively rapid antibiotic release and bacterial resistance caused by random antibiotic release.

[0004] However, the preparation methods of antibacterial coatings in the prior art are complex, and the stability and uniformity of the antibacterial layer are insufficient, requiring further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide an antibacterial coating for the surface of ePTFE implants, its preparation method and application, so as to solve the technical problem of ePTFE biocompatibility and achieve excellent antibacterial performance.

[0006] To achieve the above objectives, the present invention employs the following technical solution: According to one aspect of the present invention, a method for preparing an antibacterial coating on the surface of an ePTFE implant is provided, comprising the following steps: The ePTFE material is subjected to plasma etching, and the plasma-etched ePTFE material is immersed in a conductive organic polymer dispersion to form a conductive coating on the surface of the ePTFE material. A three-electrode system was constructed using ePTFE material with a conductive coating as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. An electropolymerization reaction was carried out in a working solution containing antibacterial active substances to form an antibacterial active substance layer on the outer layer of the ePTFE material.

[0007] The above-mentioned technical solution utilizes plasma etching to thoroughly clean the surface of ePTFE material and significantly improves the surface energy and reactivity of ePTFE material through high-energy particle bombardment. Physical etching of the ePTFE surface at the nano / micro scale can form a rougher surface morphology, thereby increasing the specific surface area and providing more "anchor points" for the subsequent adhesion of conductive coatings. This fundamentally solves the problem of easy coating detachment from both physical interlocking and chemical bonding perspectives.

[0008] After plasma activation, the surface of ePTFE material changes from hydrophobic to hydrophilic, and can be well wetted by aqueous dispersion, thus forming a continuous, uniform, and defect-free conductive coating.

[0009] By precisely controlling electrochemical parameters (such as voltage, current, polymerization time, and number of scan cycles), the thickness, density, and morphology of the outer antibacterial active substance layer can be precisely controlled, thereby affecting the antibiotic loading and release rate, making it possible to achieve long-acting and controllable drug release.

[0010] The antibacterial active substance layer, generated by in-situ polymerization on the surface of an ePTFE material with a conductive coating via electropolymerization, is tightly bonded to the conductive coating through chemical bonds and physical entanglement, rather than simple physical adsorption. Therefore, the layer-to-layer bonding is strong. Furthermore, the electropolymerization reaction is carried out under mild conditions, which helps to protect the biological activity of antibiotics.

[0011] Furthermore, before plasma etching the ePTFE material, a pretreatment step for the ePTFE material is also included; The pretreatment steps include: immersing the ePTFE material in a cleaning solution, then ultrasonically cleaning it, and then drying it; the cleaning solution is acetone, ethanol, or water.

[0012] Furthermore, the ultrasonic cleaning process can be repeated once or multiple times.

[0013] Furthermore, in the pretreatment step, different cleaning solutions are used during the multiple ultrasonic cleaning processes.

[0014] Furthermore, in the plasma etching step of the ePTFE material, the working atmosphere is an inert gas atmosphere with a gas flow rate of 10L / h-100L / h and a glow discharge power of 200W-1200W. Generally, the inert gas is argon, nitrogen, or helium, etc.

[0015] Furthermore, the conductive organic polymer dispersion is a mixture of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS) aqueous solution and (3-glycidylpropoxy)trimethoxysilane (GPTMS). In the poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution, the mass concentration of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) is 0.5%-2%; the volume ratio of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution to (3-glycidylpropoxy)trimethoxysilane is 10-100:1.

[0016] Furthermore, the plasma-etched ePTFE material is immersed in a conductive organic polymer dispersion for 1-24 hours.

[0017] Furthermore, the working solution containing antibacterial active substances is a mixture of antibiotics and fullerenes; the concentration of antibiotics in the working solution is 10mM / L-100mM / L, and the concentration of fullerenes is 0.1mM / L-1mM / L.

[0018] Furthermore, the antibiotic is ciprofloxacin or levofloxacin, and the fullerene is C60, C70, or C80.

[0019] Furthermore, the electropolymerization reaction was carried out using cyclic voltammetry, and the reaction time was 30 min to 180 min.

[0020] Furthermore, after the electropolymerization reaction is completed, the process also includes cleaning and freeze-drying the treated ePTFE material.

[0021] Using the above technical solution, a large number of silanol groups (-Si-OH) are produced on the surface of the ePTFE material through plasma etching. One end of the silane coupling agent GPTMS forms a Si-O-Si covalent bond with the silanol group via dehydration condensation, while the epoxy group at the other end undergoes a ring-opening addition reaction with the sulfonic acid group of the polystyrene sulfonic acid component in PEDOT:PSS, generating a COS covalent bond. Through this continuous covalent reaction, a stable chemical bonding interface is constructed between the silicone substrate and the PEDOT:PSS conductive coating, thereby forming a conductive coating with PEDOT on the surface of the ePTFE material.

[0022] Furthermore, using ePTFE material with a PEDOT coating as the working electrode, electrochemical co-deposition was performed in a working solution containing fullerene and antibiotic antibacterial active substances using cyclic voltammetry. By controlling the electric field to drive the fullerene to undergo electrochemical reduction and form an insoluble deposition layer, and simultaneously utilizing the electrostatic effect and physical embedding effect during the deposition process, antibiotics were simultaneously doped into this functional layer. Thus, a composite film integrating photosensitizer and antibacterial drug was constructed on the PEDOT conductive coating, forming an antibacterial active substance layer.

[0023] According to another aspect of the present invention, an antibacterial coating for the surface of an ePTFE implant is provided, which is obtained by any of the above-described preparation methods.

[0024] Furthermore, the antimicrobial coating on the surface of the ePTFE implant includes: a conductive coating attached to the surface of the ePTFE and an antimicrobial active substance layer on the surface of the conductive coating; the conductive coating is an organic polymer layer.

[0025] Furthermore, the conductive coating comprises poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) and (3-glycidylpropoxy)trimethoxysilane; The antibacterial active substance layer includes antibiotics and fullerenes.

[0026] Furthermore, the antibiotic is ciprofloxacin or levofloxacin, and the fullerene is C60, C70, or C80.

[0027] By adopting the above technical solution, a uniform conductive coating is formed on the surface of the ePTFE material, making the surface of the ePTFE material conductive, which facilitates the bonding of the antibacterial active substance layer and improves the uniformity and stability of the antibacterial layer.

[0028] The conductive coating, serving as an intermediate layer, adheres firmly to the ePTFE surface, providing a stable and reliable adhesion platform for the antimicrobial active material layer and solving the inherent "difficult adhesion" problem of ePTFE. Treating the antimicrobial active material as a separate layer facilitates the loading of large amounts of antibiotics and helps achieve sustained and long-lasting release of antibiotics, rather than rapid depletion in the initial implantation stage, thus enabling controllable loading and release of antimicrobial drugs.

[0029] The chemical cross-linking action of (3-glycidylpropoxy)trimethoxysilane firmly bonds the coating components to the ePTFE substrate, ensuring the integrity and functionality of the coating during the long-term service of the implant in the body. One end of the (3-glycidylpropoxy)trimethoxysilane molecule is a methoxysilane, which can hydrolyze and condense with trace amounts of hydroxyl groups that may be present on the ePTFE surface or with functional groups introduced through pretreatment to form a strong Si-O covalent bond. The other end is an epoxy group, exhibiting high reactivity. The epoxy groups of (3-glycidylpropoxy)trimethoxysilane can react with functional groups (such as sulfonic acid groups) in poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), and can also react with amino groups and other groups in the upper antibiotic molecules; thus, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), (3-glycidylpropoxy)trimethoxysilane and antibiotics are chemically cross-linked together, which greatly enhances the mechanical stability and bonding strength of the entire coating and prevents the coating from falling off under the flushing of liquids in the body.

[0030] The conductivity of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) may be beneficial to cell behavior and ensure the formation of a uniform and stable conductive coating film; the antioxidant properties of fullerene can reduce inflammatory responses. Together, they create a better microenvironment for cells around the implant, promoting tissue integration and reducing complications caused by foreign body reactions and inflammation.

[0031] In addition, the conductive coating can responsively promote the release of antibacterial substances in the antibacterial active substance layer under the stimulation of an external electric field, thereby achieving controllable and intelligent antibacterial inhibition by organically combining electrostimulation-responsive antibiotic biological sterilization and photodynamic physical sterilization.

[0032] According to another aspect of the present invention, an ePTFE implant is provided, comprising ePTFE material and an antimicrobial coating on the surface of the ePTFE implant prepared by any of the above-described preparation methods.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The antibacterial coating on the surface of the ePTFE implant of this application comprises a conductive coating and an antibacterial active substance layer, which helps to improve the uniformity and stability of the antibacterial coating and has good biocompatibility. Treating the antibacterial active substance as a separate layer helps to achieve sustained and long-lasting release of antibiotics, enabling controllable loading and release of antibacterial drugs. The combination of the conductive coating and the antibacterial active substance layer achieves controllable and intelligent antibacterial inhibition through the organic combination of electrically responsive antibiotic biological sterilization and photodynamic physical sterilization, realizing staged intelligent antibacterial action during and after implantation surgery.

[0034] 2. Through the chemical cross-linking of (3-glycidylpropoxy)trimethoxysilane, the coating components are firmly bonded to the ePTFE substrate, ensuring the integrity and functionality of the coating during the long-term service of the implant in the body. The conductivity of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) may benefit cell behavior and ensure the formation of a uniform and stable conductive coating film; the antioxidant properties of fullerene can reduce inflammatory responses. Together, they create a better microenvironment for the cells surrounding the implant, promoting tissue integration and reducing complications caused by foreign body reactions and inflammation.

[0035] 3. The composite coating on the surface of the ePTFE implant of the present invention has an antibacterial rate of over 99.42% against Escherichia coli and an antibacterial rate of over 99.08% against Staphylococcus aureus; and the composite coating is non-toxic or low-toxic to HaCaT cells, which helps maintain cell viability and provides growth support for cells.

[0036] 4. The method for preparing the antibacterial coating on the surface of ePTFE implants of the present invention is simple and low in cost. The prepared coating is uniform, stable, non-toxic, and environmentally friendly, and has broad application prospects. Attached Figure Description

[0037] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A bar chart comparing the Escherichia coli bacterial concentrations of ePTFE material with no composite coating on the surface in Comparative Example 1, ePTFE material with only a conductive coating in Comparative Example 2, and ePTFE material with a surface composite coating in Example 1. Figure 2 A bar chart comparing the Staphylococcus aureus bacterial concentrations of ePTFE material with no composite coating on the surface in Comparative Example 1, ePTFE material with only a conductive coating in Comparative Example 2, and ePTFE material with a surface composite coating in Example 1. Figure 3 Comparison chart of cell viability obtained from cell viability testing of ePTFE material with no composite coating on the surface in Comparative Example 1, ePTFE material with only conductive coating in Comparative Example 2, and ePTFE material with surface composite coating in Example 1; Figure 4 Comparison of cell fluorescence staining results obtained from cell viability testing of ePTFE material with no composite coating on the surface in Comparative Example 1, ePTFE material with only conductive coating in Comparative Example 2, and ePTFE material with surface composite coating in Example 1. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0039] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0040] To further illustrate the present invention, the following embodiments are provided for detailed description. All raw materials used in the following embodiments of the present invention are commercially available products.

[0041] Example 1 Antibacterial coating prepared on the surface of ePTFE material S1. Pre-treat the ePTFE material.

[0042] The ePTFE material was immersed in a cleaning solution and then ultrasonically cleaned. In this embodiment, the ePTFE material was ultrasonically cleaned three times, using acetone, ethanol, and deionized water as the cleaning solutions, respectively. The power of each ultrasonic cleaning was 150W, the temperature was 37°C, and the time was 10 min, 30 min, and 30 min, respectively. Subsequently, the ultrasonically cleaned ePTFE material was dried at 40°C for 2 hours.

[0043] S2. The pretreated ePTFE material from step S1 is subjected to plasma etching under an argon atmosphere, a gas flow rate of 50 L / h, and a glow discharge power of 800 W for 10 min. After etching, the ePTFE is transferred to a conductive organic polymer dispersion and fully immersed for 24 h. After immersion, the ePTFE material is thoroughly cleaned with deionized water to form a conductive coating on the surface of the ePTFE material.

[0044] The conductive organic polymer dispersion is prepared by dispersing poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution and (3-glycidylpropoxy)trimethoxysilane at a volume ratio of 100:1, wherein the mass concentration of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) in the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution is 1.5%.

[0045] S3. Using the ePTFE material treated in step S2 as the working electrode, a platinum mesh as the counter electrode, and Ag / AgCl as the reference electrode, electropolymerization is carried out in a working solution containing antibacterial active substances. The electropolymerization reaction is performed using cyclic voltammetry, with a voltage of 0.5V and a reaction time of 120min. After electropolymerization, the treated ePTFE material is thoroughly rinsed with deionized water to form an antibacterial active substance layer on the outer layer of the ePTFE material.

[0046] The working solution containing antibacterial active substances is a mixture of ciprofloxacin and fullerene C60; the concentration of antibiotic in the working solution is 50 mM / L and the concentration of fullerene is 0.5 mM / L.

[0047] S4. The ePTFE material processed in step S3 is freeze-dried at -40℃ and 20Pa vacuum to obtain an ePTFE material with a surface composite coating. The surface composite coating is the antibacterial coating on the surface of the ePTFE implant.

[0048] Example 2 The difference between this embodiment and Embodiment 1 is that: In step S1, the ePTFE material is ultrasonically cleaned twice, with the cleaning solutions used for the two ultrasonic cleanings being acetone and deionized water, respectively, and the ultrasonic cleaning times being 10 min and 30 min, respectively.

[0049] In step S2, the plasma etching conditions are a gas flow rate of 80 L / h and a glow discharge power of 200 W. After etching, the ePTFE is transferred to a conductive organic polymer dispersion and fully immersed for 12 h. In step S2, the conductive organic polymer dispersion is formed by dispersing poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution and (3-glycidylpropoxy)trimethoxysilane at a volume ratio of 50:1, wherein the mass concentration of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) in the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution is 0.5%.

[0050] In step S3, the electropolymerization reaction time is 30 min; the working solution containing antibacterial active substances is a mixture of levofloxacin and fullerene C70; in the working solution, the concentration of antibiotic is 100 mM / L and the concentration of fullerene is 1 mM / L.

[0051] All other steps and conditions are the same.

[0052] Example 3 The difference between this embodiment and Embodiment 1 is that: In step S1, the ePTFE material is ultrasonically cleaned twice, with the cleaning solutions used for the two ultrasonic cleanings being ethanol and deionized water, respectively, and the ultrasonic cleaning times being 30 min and 30 min, respectively.

[0053] In step S2, the plasma etching conditions are a gas flow rate of 10 L / h and a glow discharge power of 1000 W. After etching, the ePTFE is transferred to a conductive organic polymer dispersion and fully immersed for 6 hours. In step S2, the conductive organic polymer dispersion is formed by dispersing poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution and (3-glycidylpropoxy)trimethoxysilane at a volume ratio of 10:1, wherein the mass concentration of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) in the poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution is 1.0%.

[0054] In step S3, the electropolymerization reaction time is 180 min; the working solution containing antibacterial active substances is a mixture of ciprofloxacin and fullerene C80; in the working solution, the concentration of antibiotic is 10 mM / L and the concentration of fullerene is 0.1 mM / L.

[0055] All other steps and conditions are the same.

[0056] Example 4 The difference between this embodiment and Embodiment 1 is that: In step S1, the ePTFE material is ultrasonically cleaned only once. The cleaning solution used for ultrasonic cleaning is deionized water, and the ultrasonic cleaning time is 30 minutes.

[0057] In step S2, the plasma etching conditions are a gas flow rate of 100 L / h and a glow discharge power of 1200 W; after etching, the ePTFE is transferred to a conductive organic polymer dispersion and fully immersed for 1 h. In step S2, the conductive organic polymer dispersion is formed by dispersing poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution and (3-glycidylpropoxy)trimethoxysilane at a volume ratio of 10:1, wherein the mass concentration of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) in the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution is 2.0%.

[0058] In step S3, the electropolymerization reaction time is 30 min.

[0059] All other steps and conditions are the same.

[0060] Comparative Example 1 The difference between this comparative example and Example 1 is that: Only the ePTFE material is pretreated, and the pretreatment steps and conditions are the same as step S1 in Example 1; but the treatment in steps S2-S4 in Example 1 is not involved.

[0061] This comparative example yields pretreated ePTFE material.

[0062] Comparative Example 2 The difference between this comparative example and Example 1 is that: Only the ePTFE material was pretreated, plasma etched, and electropolymerized. The pretreatment steps and conditions were the same as step S1 in Example 1, the plasma etching steps and conditions were the same as step S2 in Example 1, and the electropolymerization steps and conditions were the same as step S3 in Example 1. The treatment in step S4 of Example 1 was not involved.

[0063] This comparative example yields an ePTFE material with a surface conductive coating.

[0064] Test case Test of antibacterial effect Escherichia coli and Staphylococcus aureus were selected as representatives of Gram-negative and Gram-positive bacteria, respectively, for antibacterial efficacy testing.

[0065] Escherichia coli and Staphylococcus aureus were routinely revived in nutrient broth medium, and bacterial concentrations of 1×10⁻⁶ were prepared respectively. 7 Escherichia coli CFU / ml, bacterial concentration 1×10⁻⁶ 7 A suspension of Staphylococcus aureus at CFU / ml.

[0066] Circular ePTFE materials with a diameter of 1.25 cm and a thickness of 1 mm prepared in Examples 1-4, each with a surface composite coating, as well as pretreated ePTFE materials and ePTFE materials with a surface conductive coating prepared in Comparative Examples 1-2, were respectively mixed with bacteria at a concentration of 1×10⁻⁶. 7 1 ml of a CFU / ml suspension of Escherichia coli or Staphylococcus aureus was co-cultured at 37°C.

[0067] After co-culturing for 24 hours, the bacterial culture of the corresponding strain and group was aspirated, and its OD600 reading was read using a TECAN microplate reader. The corresponding bacterial concentration was then calculated according to the formula.

[0068] The calculated antibacterial rates of the ePTFE materials with surface composite coatings in Examples 1-4 against Escherichia coli are shown in Table 1, compared with the ePTFE materials without surface composite coatings in the comparative examples; the antibacterial rates of the ePTFE materials with surface composite coatings in Examples 1-4 against Staphylococcus aureus are shown in Table 2.

[0069] Table 1. Antibacterial rate of ePTFE materials in Examples 1-4 against Escherichia coli compared with Comparative Example 1.

[0070] Table 2 shows the antibacterial rate of ePTFE materials in Examples 1-4 against Staphylococcus aureus compared to Comparative Example 1.

[0071] The bar charts showing the Escherichia coli bacterial concentrations of ePTFE material with a surface composite coating in Example 1, ePTFE material without a surface composite coating in Comparative Example 1, and ePTFE material with only a conductive coating in Comparative Example 2 are shown below. Figure 1 The corresponding bar chart for Staphylococcus aureus bacterial concentration is shown below. Figure 2 .

[0072] Combination Figure 1 It can be seen that the bacterial solutions containing the ePTFE material without a composite coating in Comparative Example 1 and the ePTFE material with only a conductive coating in Comparative Example 2 contained a large number of live Escherichia coli bacteria. The number of Escherichia coli in the bacterial solution containing the ePTFE material with a composite coating provided in Example 1 was significantly reduced, indicating that the sample of Example 1 had good anti-Escherichia coli ability. Furthermore, due to the release of some antibiotics, most of the Escherichia coli died. Specifically, compared with Comparative Example 1 and the sample provided in Comparative Example 1, the sample provided in Example 1 achieved an inhibition rate of 99.99% against Escherichia coli.

[0073] Combination Figure 2 It can be seen that the bacterial solutions containing the ePTFE material without a composite coating in Comparative Example 1 and the ePTFE material with only a conductive coating in Comparative Example 2 contained a large number of live Staphylococcus aureus bacteria. The number of Staphylococcus aureus bacteria in the bacterial solution containing the ePTFE material with a composite coating provided in Example 1 was significantly reduced, indicating that the sample of Example 1 had good anti-Staphylococcus aureus ability. Furthermore, due to the release of some antibiotics, most of the Staphylococcus aureus bacteria died. Specifically, the sample provided in Example 1 achieved an antibacterial rate of 99.96% against Staphylococcus aureus.

[0074] According to Tables 1 and 2, compared with the sample provided in Comparative Example 1, the ePTFE materials with surface composite coatings provided in Examples 2-4 achieved antibacterial rates of 99.71%, 99.37% and 99.42% against Escherichia coli, respectively; and antibacterial rates of 99.29%, 99.13% and 99.08% against Staphylococcus aureus, respectively.

[0075] Cell viability assay Immortalized human epidermal keratinocytes (Hacat) were selected for cell viability testing. Hacat cells were revived and cultured in DMEM complete medium supplemented with 10% fetal bovine serum, and a cell suspension with a concentration of 20,000 cells / mL was prepared.

[0076] The ePTFE materials with surface composite coatings prepared in Examples 1-4, the ePTFE material without surface composite coating prepared in Comparative Example 1, and the ePTFE material with only conductive coating prepared in Comparative Example 2 were co-cultured with 1 mL of cell suspension at a cell concentration of 20,000 cells / mL at 37°C and 5% CO2. The ePTFE materials in Examples 1-4 and Comparative Examples 1-2 were all spherical, with a diameter of 1.25 cm and a thickness of 1 mm.

[0077] Routine medium changes were performed during the 7-day co-culture period. After 7 days of co-culture, the cell viability was assessed using the Alamarblue cell viability assay reagent provided by Thermo Fisher Scientific, following the instructions for use, and the fluorescence intensity was measured using a TECAN microplate reader. Cell viability was determined based on the fluorescence intensity. A comparison of cell viability between the co-cultured ePTFE material prepared in Comparative Example 1 (without a composite coating), the ePTFE material prepared in Comparative Example 2 (with only a conductive coating), and the ePTFE material prepared in Example 1 (with a composite coating) is provided below. Figure 3 .

[0078] In addition, for the samples co-cultured using the same method, cells were stained with fluorescence using the LIVE / DEAD cell viability staining kit provided by Thermo Fisher Scientific according to the instructions, and photographed under an upright fluorescence microscope. Cell viability was determined based on the distribution and density of green fluorescence. The fluorescence staining results of cells co-cultured with the ePTFE material prepared in Comparative Example 1 (without a composite coating), the ePTFE material prepared in Comparative Example 2 (with only a conductive coating), and the ePTFE material prepared in Example 1 (with a composite coating) are shown in the attached images. Figure 4 .

[0079] Combination Figure 3 Comparative Example 1 showed the lowest cell viability and the highest bacterial concentration (approximately 2.0 × 10⁻⁶). 4The CFU / mL concentration indicates that the growth of HaCaT cells on the surface of the ePTFE material without a composite coating was significantly inhibited; the cell viability of Comparative Example 2 was slightly higher than that of Comparative Example 1, with a bacterial concentration of approximately 1.2 × 10⁻⁶ CFU / mL. 4 Even at CFU / mL, the bacteria concentration remained significantly toxic or inhibitory to cells. Example 1 showed the highest cell viability and the lowest bacterial concentration, approximately 2.0 × 10³ CFU / mL, indicating that HaCaT cells exhibited optimal growth on the surface of the ePTFE material with the surface composite coating, with minimal bacterial influence. Therefore, compared to the ePTFE material without a load coating in Comparative Example 1 or the ePTFE material with only a conductive coating in Comparative Example 2, the ePTFE material with the surface composite coating significantly inhibits bacterial growth, reduces bacterial concentration in the co-culture system, and is non-toxic or low-toxic to HaCaT cells, thus promoting cell growth. In other words, the ePTFE material with the surface composite coating provided in Example 1 is significantly superior to Comparative Examples 1 and 2 in maintaining high HaCaT cell viability, demonstrating good cell compatibility while controlling bacterial proliferation. The antibacterial active substances in the surface composite coating of the ePTFE material are slowly released during culture, and the physical barrier formed by the composite coating also helps protect cells from bacterial invasion.

[0080] Combination Figure 4 In Comparative Example 1, the number of cells was small, and their morphology may have been shrunken or incomplete, with weak fluorescence intensity, indicating low cell survival rate, inhibited proliferation, or significant apoptosis / necrosis. In Comparative Example 2, the number of cells was greater than that of Comparative Example 1, and their morphology was relatively intact, with moderate fluorescence intensity, indicating that the cell condition had improved, but had not yet reached the ideal growth state. In Example 1, the number of cells was significantly greater than that of the two pairs of examples, and their morphology was relaxed, well spread out, and their fluorescence was bright and uniform, indicating high cell viability, active proliferation, and healthy morphology.

[0081] The highest cell density was observed in Example 1, further illustrating that, comparatively, the surface of the ePTFE material with the composite coating is most conducive to the proliferation and survival of HaCaT cells. Healthy HaCaT cells should exhibit typical epithelial cell morphology: well-spread, polygonal, and with tight intercellular connections. In contrast, the cells in Comparative Example 1 were shrunken and fragmented, potentially leading to apoptosis or necrosis. The cells in Example 1, however, exhibited the morphology of healthy HaCaT cells, demonstrating that the ePTFE material with the composite coating possesses good biocompatibility and the ability to support cell adhesion. This is because the ePTFE material with the composite coating can effectively inhibit bacterial proliferation, reduce direct bacterial attack on cells or toxic metabolites, and possess antioxidant and anti-inflammatory effects. It can alleviate cell damage caused by bacterial-induced oxidative stress or inflammatory responses, and the material itself can provide growth support for cells, promoting cell adhesion, spreading, or proliferation.

[0082] In summary, the antibacterial coating on the surface of the ePTFE implant provided in Embodiment 1 of the present invention has good antibacterial properties.

[0083] This invention first physically etches the ePTFE surface to create a rougher surface morphology, thereby increasing the specific surface area and providing more "anchor points" for the subsequent adhesion of the conductive coating. This fundamentally solves the problem of easy coating detachment from both physical interlocking and chemical bonding perspectives. Plasma etching technology is used to improve the surface energy and reactivity of the ePTFE material. The activated ePTFE material surface changes from hydrophobic to hydrophilic, allowing it to be well wetted by aqueous dispersions. When immersed in a conductive organic polymer dispersion, a continuous, uniform, and defect-free conductive coating can be formed.

[0084] The conductive coating is formed using an impregnation method, which is simple to operate and easy to scale up industrially. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) has good conductivity. Forming a conductive coating on the ePTFE material surface before the formation of the antibacterial active substance layer allows the hydrophilic conductive surface to interfere with initial bacterial adhesion, thus ensuring the quality of the subsequent antibacterial active substance layer and avoiding bacterial contamination. Furthermore, for implants that require interaction with electroactive tissues (such as muscles and nerves), the conductive coating may be more conducive to cell adhesion and growth, accelerating healing and reducing the risk of infection from foreign body reactions; the antibacterial effect can even be further enhanced by applying a weak external electric field.

[0085] The thickness, density, and morphology of the antibacterial active substance layer can be controlled and adjusted by precisely controlling electrochemical parameters, thereby enabling the regulation of antibiotic loading rate and release rate, and providing the possibility of achieving long-acting and controllable drug release.

[0086] Antibiotics possess highly effective and broad-spectrum bactericidal properties, providing rapid and potent antibacterial effects, and directly killing common implant-related bacteria (such as Escherichia coli and Staphylococcus aureus). Fullerenes, with their unique spherical structure and hydrophobicity, can insert into bacterial cell membranes, physically disrupting their integrity and causing leakage of bacterial contents, leading to bacterial death. This physical mechanism is completely different from the biochemical target action of antibiotics, thus making it extremely difficult to induce antibiotic resistance in bacteria.

[0087] By combining "plasma activation" with "in-situ electrochemical polymerization", excellent adhesion is ensured between the coating and the ePTFE substrate, as well as between the coating layers, which also helps to extend the service life of the functional coating in vivo.

[0088] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0089] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

Claims

1. A method for preparing an antibacterial coating on the surface of an ePTFE implant, characterized in that, Includes the following steps: The ePTFE material is subjected to plasma etching, and the plasma-etched ePTFE material is immersed in a conductive organic polymer dispersion to form a conductive coating on the surface of the ePTFE material. A three-electrode system was constructed using ePTFE material with a conductive coating as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. An electropolymerization reaction was carried out in a working solution containing antibacterial active substances to form an antibacterial active substance layer on the outer layer of the ePTFE material.

2. The preparation method according to claim 1, characterized in that, Before plasma etching of ePTFE material, a pretreatment step for ePTFE material is also included; The pretreatment step includes: ultrasonically cleaning the ePTFE material with a cleaning solution, and then drying it; The cleaning solution is acetone, ethanol, or water.

3. The preparation method according to claim 1, characterized in that, In the plasma etching step of the ePTFE material, the working atmosphere is an inert gas atmosphere, the gas flow rate is 10L / h-100L / h, and the glow discharge power is 200W-1200W.

4. The preparation method according to claim 1, characterized in that, The conductive organic polymer dispersion is a mixture of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution and (3-glycidylpropoxy)trimethoxysilane. The mass concentration of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) in the poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution is 0.5%-2%. The volume ratio of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) aqueous solution to (3-glycidylpropoxy)trimethoxysilane is (10-100):

1.

5. The preparation method according to claim 4, characterized in that, The working solution containing antibacterial active substances is a mixture of antibiotics and fullerenes; In the working solution, the concentration of the antibiotic is 10 mM / L-100 mM / L, and the concentration of the fullerene is 0.1 mM / L-1 mM / L.

6. The preparation method according to claim 1, characterized in that, The electropolymerization reaction is carried out using cyclic voltammetry, and the reaction time is 30 min to 180 min.

7. The preparation method according to claim 1, characterized in that, The electropolymerization reaction is completed, and the process also includes cleaning and freeze-drying the treated ePTFE material.

8. An antibacterial coating on the surface of an ePTFE implant, characterized in that, Obtained by the preparation method described in any one of claims 1-7.

9. The antibacterial coating on the surface of the ePTFE implant according to claim 8, characterized in that, include: A conductive coating is attached to the surface of the ePTFE, and an antibacterial active substance layer is formed on the surface of the conductive coating; the conductive coating is an organic polymer layer; the antibacterial active substance layer includes antibiotics and fullerenes.

10. An ePTFE implant, characterized in that, Includes ePTFE material and an antibacterial coating on the surface of an ePTFE implant prepared by the preparation method described in any one of claims 1-7.

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