Composite nano antibacterial coating with layered structure and preparation method thereof

Abstract

The invention provides a composite nano antibacterial coating with a layered structure and a preparation method, and relates to the technical field of surface modification of medical instruments, and the preparation method comprises the following steps: preparing a pre-polymerization solution: preparing a graphene oxide aqueous solution with the concentration of 0.1 mg / mL to 1mg / mL by using deionized water, adding methacrylic acid hyaluronic acid and a photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate salt into the graphene oxide aqueous solution, stirring and dissolving, and performing ultrasonic treatment to obtain a GO-coated HAMA prepolymer solution; treating the substrate: cleaning the substrate with 75% ethanol, and airing; the substrate is placed on a polytetrafluoroethylene bottom plate, a polytetrafluoroethylene gasket and a transparent quartz glass plate are stacked, and the GO-coated HAMA prepolymerization liquid is injected into a cavity of a mold after the substrate and the transparent quartz glass plate are clamped. According to the present invention, the efficient killing effect on escherichia coli and staphylococcus aureus is provided, the sterilization rates respectively achieve 100% and 99.9%, and the bacterial infection problem on the surface of the implantable medical device can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of surface modification of medical devices, and in particular to a composite nano antibacterial coating with a layered structure and a preparation method thereof. Background Art

[0002] With the widespread clinical application of implantable medical devices, bacterial infections and biocompatibility issues caused by their surfaces are becoming increasingly prominent. According to statistics, the global rate of secondary surgeries due to implant infections is as high as 5%-10% each year, which not only directly threatens the safety of patients' lives, but also significantly increases medical costs.

[0003] Traditional surface modification technologies, such as antibiotic coatings and single metal ion loading, can inhibit infection in the short term, but they have many defects. For example, the antibacterial effect is short and difficult to work in the long term; it easily leads to an increased risk of drug resistance; and the biological activity is insufficient, which cannot meet the biocompatibility requirements of medical devices.

[0004] In recent years, composite nano-antibacterial coatings have become a research hotspot due to their multifunctional synergistic effects, but they still face some technical bottlenecks that need to be broken through. Most coatings rely on metal ion release or physical sterilization (such as nanoneedle structures), which are easily affected by bacterial biofilm resistance. For example, the antibacterial effect of silver fixed on the surface of laser nanostructured titanium will decrease significantly after 6 days; although copper oxide nanoparticles have broad-spectrum antibacterial properties, their inhibitory effect on methicillin-resistant Staphylococcus aureus (MRSA) is limited. In addition, photocatalytic antibacterial (such as TiO2) requires ultraviolet light excitation, and ultraviolet light is difficult to penetrate human tissue, which greatly limits its clinical application. To this end, we propose a layered composite nano-antibacterial coating for modifying the surface of implantable medical devices to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite nano antibacterial coating with a layered structure and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: comprising the following steps:

[0007] Preparation of a prepolymer solution: using deionized water to prepare a graphene oxide aqueous solution with a concentration of 0.1 mg / mL to 1 mg / mL, adding methacrylated hyaluronic acid and a photoinitiator, phenyl (2,4,6-trimethylbenzoyl) lithium phosphate, to the graphene oxide aqueous solution, stirring and dissolving, and then ultrasonicating to obtain a GO@HAMA prepolymer solution;

[0008] Treat the substrate: Wash the substrate with 75% ethanol and let it dry;

[0009] Preparation of the coating: placing the substrate on a polytetrafluoroethylene base plate, stacking a polytetrafluoroethylene gasket and a transparent quartz glass plate, clamping, injecting the GO@HAMA prepolymer solution into the mold cavity, and irradiating with ultraviolet light to induce crosslinking to form a hydrogel;

[0010] Post-processing: After removing the template, the sample is moved into a copper ion solution for immersion, and dried to obtain the composite nano antibacterial coating.

[0011] Furthermore, the concentration of the graphene oxide aqueous solution is 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.5 mg / mL, 0.7 mg / mL or 1 mg / mL.

[0012] Furthermore, the concentration of the methacrylated hyaluronic acid in the solution is 10 mg / mL, and the concentration of the photoinitiator in the solution is 1 mg / mL.

[0013] Furthermore, the conditions of the ultraviolet light exposure are: ultraviolet parallel exposure machine, power 150W, and exposure time 3 minutes.

[0014] Furthermore, the concentration of the copper ion solution is 0.1-1 mol / L, and the immersion time is 24 hours.

[0015] Furthermore, the drying temperature is 30° C. and the drying time is 24 hours.

[0016] Furthermore, the substrate is a thin flat polyurethane film.

[0017] Furthermore, a composite nano-antibacterial coating with a layered structure is prepared by the method for preparing a composite nano-antibacterial coating with a layered structure, wherein the composite nano-antibacterial coating has a two-dimensional layered structure.

[0018] Compared with the prior art, the advantages and positive effects of the present invention are:

[0019] 1. The present invention has a highly effective killing effect on Escherichia coli and Staphylococcus aureus, with sterilization rates reaching 100% and 99.9% respectively, and can effectively solve the problem of bacterial infection on the surface of implantable medical devices.

[0020] 2. The coating of the present invention can enhance the fracture strength of the substrate while maintaining a certain flexibility, meeting the mechanical performance requirements of medical devices. The coating presents a two-dimensional layered structure, which is conducive to the synergistic effect of each component and improves the comprehensive performance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The process flow chart for preparing the composite nano antibacterial coating with a layered structure of the present invention;

[0022] Figure 2 Optical images before (a) and after (b) the bending test of the present invention;

[0023] Figure 3 This is a typical stress-strain curve diagram of the present invention;

[0024] Figure 4 The scanning electron micrographs of the double-layer membranes with different GO contents of the present invention;

[0025] Figure 5 Graph showing the antibacterial effect of the coating of the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] A composite nano-antibacterial coating with a layered structure and a preparation method thereof, wherein the prepared GO@HAMA antibacterial nano-coating is named "GO-x", where "x" represents the mass concentration of GO (mgmL -1 ), the six GO@HAMA antibacterial nanocoatings with different GO contents were prepared and recorded as “GO-0.1”, “GO-0.2”, “GO-0.3”, “GO-0.5”, “GO-0.7” and “GO-1.0”, respectively.

[0028] Example 1: Preparation of GO-0.1 antibacterial nanocoating

[0029] Prepare a 0.1 mg / mL graphene oxide (GO) aqueous solution: weigh 0.1 mg of GO powder, add it to 1 mL of deionized water, and ultrasonically disperse it for 30 minutes to obtain a uniform GO aqueous solution. To the above GO aqueous solution, add 0.1 mL of 10 mg / mL HAMA solution and 0.1 mL of 1 mg / mL LAP solution, stir for 10 minutes until completely dissolved, and ultrasonicate for 10 minutes to remove bubbles in the solution to obtain a GO@HAMA prepolymer solution.

[0030] A thin polyurethane flat sheet was washed with 75% ethanol and air-dried, then placed on a polytetrafluoroethylene (PTFE) substrate. A 1mm-thick PTFE gasket and a transparent quartz glass plate were stacked and clamped. A GO@HAMA prepolymer solution was injected into the mold cavity using a syringe. The mold was then exposed to a UV light source (150°C, OAI) for 3 minutes to initiate a cross-linking reaction and form a hydrogel. After removing the template, the sample was immersed in a 0.1 mol / L copper chloride solution for 24 hours and then dried at 30°C for 24 hours to obtain the GO-0.1 antibacterial nanocoating.

[0031] Example 2: Preparation of GO-0.2 antibacterial nanocoating

[0032] Except that the concentration of GO was changed to 0.2 mg / mL, other steps were the same as those in Example 1 to prepare a GO-0.2 antibacterial nanocoating.

[0033] Example 3: Preparation of GO-0.3 antibacterial nanocoating

[0034] Except that the concentration of GO was changed to 0.3 mg / mL, other steps were the same as those in Example 1 to prepare a GO-0.3 antibacterial nanocoating.

[0035] Example 4: Preparation of GO-0.5 antibacterial nanocoating

[0036] Except that the concentration of GO was changed to 0.5 mg / mL, other steps were the same as those in Example 1 to prepare a GO-0.5 antibacterial nanocoating.

[0037] Example 5: Preparation of GO-0.7 antibacterial nanocoating

[0038] Except that the concentration of GO was changed to 0.7 mg / mL, other steps were the same as those in Example 1 to prepare a GO-0.7 antibacterial nanocoating.

[0039] Example 6: Preparation of GO-1.0 antibacterial nanocoating

[0040] Except that the concentration of GO was changed to 1.0 mg / mL, other steps were the same as those in Example 1 to prepare a GO-1.0 antibacterial nanocoating.

[0041] The mechanical properties of the seven prepared double-layer membranes were preliminarily determined through bending experiments. Figure 2 Optical images of the substrate blank, GO-0.1, GO-0.2, GO-0.3, GO-0.5, GO-0.7 and GO-1.0 before and after the bending test. Figure 2 As can be seen in a, the coatings have a uniform macroscopic morphology, and with the increase of GO concentration, the color of the response layer of the GO@HAMA antibacterial coating gradually darkens. Figure 2As can be seen in b, the GO@PVDF layers of GO-0.7 and GO-1.0 are easily brittle and have poor mechanical properties, while the bilayer membranes with other GO concentrations are not damaged after bending;

[0042] Figure 3 It is the state of the substrate blank sample, GO-0.1, GO-0.2, GO-0.3, and GO-0.5 at three representative time points in the tensile test experiment (the start of the experiment, the frame before fracture, and fracture), which corresponds to and intuitively presents the stress-strain curve in the figure above. Tiny fractures appeared in the samples of GO-0.1 and GO-0.2, and the double layers were simultaneously broken in the next second; while a larger crack appeared in the GO@PVDF layer of GO-0.3, but the double layers were also broken immediately; and for GO-0.5, the GO@PVDF layer broke completely first, and then after a period of stretching, the substrate layer was broken. With the increase of GO concentration, the fracture stress of the double-layer membrane first increased and then decreased, and the fracture strain gradually decreased. In general, the mechanical properties gradually weakened. The above results show that the coating improved the fracture strength of the substrate sample and reduced the strain of the substrate sample;

[0043] Figure 4 The following are scanning electron micrographs of bilayer films with different GO contents. The SEM cross-sectional images show that the GO@HAMA nanocoating exhibits a two-dimensional layered structure, which is a characteristic structure of graphene oxide films. Furthermore, as the GO concentration increases, the two-dimensional layered structure becomes more pronounced and denser. These results indicate that a series of tightly connected GO@HAMA nanocoatings with heterogeneous structures have been successfully prepared.

[0044] Figure 5 The results showed that the GO@HAMA nanocoating had a contact killing effect on Escherichia coli and Staphylococcus aureus. The killing rates of the substrate against Escherichia coli and Staphylococcus aureus were 11.9% and 14.6%, respectively, indicating almost no antibacterial effect. When the substrate had a GO@HAMA nanocoating, the killing rate of Escherichia coli reached 100%, and that of Staphylococcus aureus reached 99.9%.

[0045] The antibacterial nanocoatings with different GO contents prepared in the above examples all had good antibacterial properties and certain mechanical properties after testing. Among them, the coatings with GO-0.1 to GO-0.5 had better mechanical properties, while the coatings with GO-0.7 and GO-1.0 had relatively poor mechanical properties, but all showed excellent antibacterial properties.

[0046] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a composite nano antibacterial coating with a layered structure, characterized in that: The steps include: Preparation of a prepolymer solution: using deionized water to prepare a graphene oxide aqueous solution with a concentration of 0.1 mg / mL to 1 mg / mL, adding methacrylated hyaluronic acid and a photoinitiator, phenyl (2,4,6-trimethylbenzoyl) lithium phosphate, to the graphene oxide aqueous solution, stirring and dissolving, and then ultrasonicating to obtain a GO@HAMA prepolymer solution; Treat the substrate: Wash the substrate with 75% ethanol and let it dry; Preparation of the coating: placing the substrate on a polytetrafluoroethylene base plate, stacking a polytetrafluoroethylene gasket and a transparent quartz glass plate, clamping, injecting the GO@HAMA prepolymer solution into the mold cavity, and irradiating with ultraviolet light to induce crosslinking to form a hydrogel; Post-processing: After removing the template, the sample is moved into a copper ion solution for immersion, and dried to obtain the composite nano antibacterial coating.

2. The method for preparing a composite nano antibacterial coating with a layered structure according to claim 1, characterized in that: The concentration of the graphene oxide aqueous solution is 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.5 mg / mL, 0.7 mg / mL or 1 mg / mL.

3. The method for preparing a composite nano antibacterial coating with a layered structure according to claim 2, characterized in that: The concentration of the methacrylated hyaluronic acid in the solution is 10 mg / mL, and the concentration of the photoinitiator in the solution is 1 mg / mL.

4. The method for preparing a composite nano antibacterial coating with a layered structure according to claim 3, characterized in that: The conditions of the ultraviolet light exposure are: ultraviolet parallel exposure machine, power 150W, exposure time 3 minutes.

5. The method for preparing a composite nano antibacterial coating with a layered structure according to claim 4, characterized in that: The concentration of the copper ion solution is 0.1-1 mol / L, and the immersion time is 24 hours.

6. The method for preparing a composite nano antibacterial coating with a layered structure according to claim 5, characterized in that: The drying temperature is 30° C. and the drying time is 24 hours.

7. The method for preparing a composite nano antibacterial coating with a layered structure according to claim 6, characterized in that: The substrate is a thin flat polyurethane film.

8. A layered composite nano-antibacterial coating prepared by the method for preparing a layered composite nano-antibacterial coating according to claim 7, characterized in that: The composite nano antibacterial coating presents a two-dimensional layered structure.

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