Magnesium alloy surface MGO-MFP5 composite coating and preparation method and application thereof

Abstract

The invention discloses a magnesium alloy surface MGO-MFP5 composite coating and a preparation method and application thereof. The preparation method comprises the steps that a magnesium alloy is ground, cleaned, subjected to sodium hydroxide alkaline etching pretreatment and subjected to ultraviolet sterilization, and then the surface of the magnesium alloy is coated with a mussel adhesion protein solution through a trace drop deposition method to form the MGO-MFP5 composite coating. According to the preparation method, the MgO thin film is formed on the surface of the magnesium alloy through alkali etching, then MFP5 is stably adhered to the surface of the magnesium alloy through the chemical adsorption effect between Dopa molecules of mussel adhesion protein and MgO to form the MgO-MFP5 composite coating, the process is simple, operability is high, the application range is wide, and the obtained composite coating has good biocompatibility, can promote cell proliferation and can be used for preparing the magnesium alloy composite coating. Meanwhile, the antibacterial performance is remarkably improved, adhesion and reproduction of common pathogenic bacteria such as staphylococcus aureus and escherichia coli are inhibited, and the magnesium-based bone implant is suitable for preparing bone fixing instruments, cardiovascular stents and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and in particular relates to an MGO-MFP5 composite coating on a magnesium alloy surface, a preparation method thereof, and an application thereof. Background Art

[0002] Magnesium is one of the essential trace elements for the human body. It is widely present in bones and soft tissues and can participate in bone metabolism and cell signaling. The mechanical properties of magnesium alloys are similar to those of human bones, and they have good biodegradability. They can be gradually absorbed by the human body during bone tissue repair, thus avoiding the need for secondary surgical removal. However, the rapid degradation rate of magnesium in the body can easily lead to mechanical failure, and its surface is prone to breeding bacteria and causing infection. In the existing technology, surface modification mainly improves corrosion resistance through micro-arc oxidation or polymer coating, but there are problems with complex processes or insufficient biocompatibility.

[0003] Mussel protein (MEFP) is extracted from mussels in the ocean and has been widely studied for its good adhesion and biocompatibility. Mussel protein can also maintain high strength and good elasticity in a humid environment. These properties make mussel protein an ideal bio-coating material that can be used to improve the surface properties and biocompatibility of implants. The DOPA group in mussel protein can form a stable chemical bond with the metal surface, thereby enhancing the adhesion and corrosion resistance of the coating. At the same time, mussel protein contains a large number of positively charged amino acids. These positively charged amino acids can undergo strong electrostatic interactions with the negative charges on the bacterial cell membrane, destroying the integrity of the cell membrane and causing leakage of cell contents, thereby inhibiting bacterial growth and even causing bacterial death. Summary of the Invention

[0004] Based on this, the main purpose of the present invention is to provide a method for preparing an MgO-MFP5 composite coating on the surface of a magnesium alloy. First, an MgO film is formed on the surface of the magnesium alloy by NaOH alkaline heat treatment, and then the chemical adsorption between the Dopa group in type 5 mussel adhesion protein (MEFP-5) and MgO is used to make MFP5 stably adhere to the surface of the magnesium alloy to form an MgO-MFP5 composite coating. The method has the characteristics of simple process, strong operability and wide applicability.

[0005] Another object of the present invention is to provide an MgO-MFP5 composite coating on the surface of a magnesium alloy obtained by the above-mentioned preparation method, which combines the multiple excellent properties of the MgO film and the MFP5 coating. On the one hand, the MgO film provides good corrosion resistance, biological stability and the ability to promote cell growth. On the other hand, the MFP5 coating gives the composite coating significant antibacterial properties and cell activity promotion effects.

[0006] Another object of the present invention is to provide a magnesium alloy material containing a MgO-MFP5 composite coating, which includes the aforementioned MgO-MFP5 composite coating.

[0007] Another object of the present invention is to provide the use of the MgO-MFP5 composite coating, or the magnesium alloy material containing the MgO-MFP5 composite coating, in the preparation of magnesium-based bone implants with antibacterial and cell proliferation-promoting effects, wherein the MgO-MFP5 composite coating effectively reduces the risks of various complications caused by medical magnesium products during clinical use, such as bacterial infection and tissue rejection reactions. By reducing the occurrence of these complications, not only can the service life of medical magnesium products be extended, but their medical effects can also be significantly improved.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A first aspect of the present invention provides a method for preparing an MGO-MFP5 composite coating on a magnesium alloy surface, comprising the following steps:

[0010] (1) Cut the magnesium alloy into thin slices and polish them with 800#, 1200#, 1500#, 2000#, and 3000# sandpaper in sequence until the surface is smooth;

[0011] (2) The polished magnesium alloy was ultrasonically cleaned with anhydrous ethanol and deionized water in sequence, and then dried and labeled as Mg;

[0012] (3) Soak Mg in sodium hydroxide solution and let it stand for a while, then take it out and rinse it with deionized water. After drying, mark it as NAOH and sterilize it with ultraviolet light.

[0013] (4) diluting mussel adhesion protein type 5 (MEFP-5) with Tris buffer and filtering and sterilizing to obtain a MEFP-5 solution;

[0014] (5) The MEFP-5 solution was coated on the NAOH surface by a micro-droplet deposition method and dried in the dark to form an MGO-MFP5 composite coating.

[0015] Preferably, in step (1), the magnesium alloy sheet has a diameter of 15 mm and a thickness of 5 mm.

[0016] Preferably, in step (3), the concentration of the sodium hydroxide solution is 3 to 8 mol / L, the soaking temperature is 23 to 27° C., and the standing time is 12 to 24 hours.

[0017] More preferably, in step (3), the concentration of the sodium hydroxide solution is 5 mol / L, the soaking temperature is 25° C., and the standing time is 24 hours.

[0018] Preferably, in step (5), the concentration of the MEFP-5 solution is 0.25-1 mg / mL.

[0019] Preferably, in step (5), the coating amount of the MEFP-5 solution is 0.3 to 0.5 mL / cm 2 .

[0020] In a second aspect of the present invention, an MGO-MFP5 composite coating on a magnesium alloy surface is provided, which is prepared by any of the methods for preparing an MGO-MFP5 composite coating on a magnesium alloy surface described above, and comprises an MgO thin film layer and an MFP5 coating sequentially covering the surface of the magnesium alloy.

[0021] A third aspect of the present invention provides a magnesium alloy material containing an MGO-MFP5 composite coating, which comprises an MGO-MFP5 composite coating on the surface of the magnesium alloy.

[0022] A fourth aspect of the present invention provides use of the MgO-MFP5 composite coating or the magnesium alloy material containing the MgO-MFP5 composite coating in the preparation of a magnesium-based bone implant having antibacterial and cell proliferation promoting effects.

[0023] Preferably, the magnesium-based bone implant comprises a bone fixation device, a cardiovascular stent or a wound repair material.

[0024] The present invention first forms an MgO film by heat-treating the magnesium surface with NaOH. This structure not only significantly increases the hydrophilicity of the magnesium alloy, but also provides favorable conditions for cell attachment and growth, thereby greatly enhancing the biocompatibility of the magnesium-based material. Furthermore, the MgO film can slow the degradation rate of the magnesium alloy, further improving the corrosion resistance and biocompatibility of the material. Subsequently, a Dopa-containing MFP5 solution is drop-coated on the MgO film. The Dopa molecules form a strong adhesion to the MgO surface through chemical adsorption, allowing the MFP5 to evenly cover the magnesium surface, forming a second coating. This MFP5 coating also has excellent antibacterial properties, effectively inhibiting bacterial growth and promoting cell adhesion and proliferation.

[0025] The MgO-MFP5 composite coating prepared by this invention cleverly combines the advantages of MgO thin film and MFP5 coating. The MgO thin film slows down the corrosion of magnesium alloys and enhances the biocompatibility of magnesium-based materials. The MFP5 coating, leveraging its molecular structure, exhibits strong antibacterial properties and promotes cell adhesion. This composite coating can significantly reduce the incidence of adverse reactions such as bacterial infection and tissue rejection that may occur during clinical use of medical magnesium products, effectively extending their service life and improving medical effectiveness.

[0026] The MgO-MFP5 composite coating preparation process of the present invention is simple and efficient, has strong operability, and has wide applicability. By finely controlling the process parameters, uniform coating coverage can be achieved on the surface of medical magnesium-based materials of various shapes and sizes. It is not only suitable for common medical magnesium products such as bone fixation instruments, joint prostheses and bone nails, but can also be expanded to other biomedical materials with surface modification requirements, opening up new paths for the innovative development of biomaterials.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Improved antibacterial properties: The MFP5 in the MgO-MFP5 composite coating, due to the positively charged groups in its molecular structure, can generate strong electrostatic interactions with the negative charges on the bacterial cell membrane. This interaction can destroy the integrity of the bacterial cell membrane and cause leakage of cell contents, thereby inhibiting bacterial growth or even killing bacteria. This is of great significance in reducing the risk of postoperative infection in medical magnesium products and can effectively improve the safety of implants and the quality of postoperative recovery of patients.

[0029] (2) Significant cell adhesion and growth promotion effects: The MgO film and MFP5 coating work together to significantly improve the cell adhesion and growth ability of magnesium-based materials. The MgO film delays the degradation rate of magnesium alloys and provides a suitable microenvironment, which is conducive to cell attachment and proliferation; the MFP5 coating further enhances cell adhesion and accelerates tissue fusion and healing.

[0030] (3) Improved biocompatibility and stability: The excellent corrosion resistance and biocompatibility of the MgO-MFP5 composite coating can maintain long-term stability in the in vivo environment, helping to reduce complications caused by material degradation or corrosion and improve the service life and reliability of the implant. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : Scanning electron microscope (SEM) image of the MGO-MFP5 composite coating sample in the embodiment; wherein, M1: MGO-MFP5 composite coating sample in Example 1; M0.5: MGO-MFP5 composite coating sample in Example 2; M0.25: MGO-MFP5 composite coating sample in Example 3; NAOH: coating sample treated with sodium hydroxide in Examples 1, 2, and 3; MG: sample without any treatment in Examples 1, 2, and 3.

[0032] Figure 2These are SEM images of the MGO-MFP5 composite coating samples after immersion in SBF simulated body fluid for 7 days and 14 days in the examples; wherein, M1: MGO-MFP5 composite coating sample in Example 1; M0.5: MGO-MFP5 composite coating sample in Example 2; M0.25: MGO-MFP5 composite coating sample in Example 3; NAOH: coating sample treated with sodium hydroxide in Examples 1, 2, and 3; MG: sample without any treatment in Examples 1, 2, and 3.

[0033] Figure 3 are the water contact angle and average contact angle of the MGO-MFP5 composite coating samples in the examples; wherein, M1: the MGO-MFP5 composite coating sample in Example 1; M0.5: the MGO-MFP5 composite coating sample in Example 2; M0.25: the MGO-MFP5 composite coating sample in Example 3; NAOH: the coating sample treated with sodium hydroxide in Examples 1, 2, and 3; MG: the sample without any treatment in Examples 1, 2, and 3.

[0034] Figure 4 These are live and dead cell staining images of the MGO-MFP5 composite coating samples in the examples after culturing for 1, 3, and 5 days; wherein, (a) macrophages RAW264.7; (b) human fibroblasts HDF; (c) human chondrocytes HC; M1: MGO-MFP5 composite coating sample in Example 1; M0.5: MGO-MFP5 composite coating sample in Example 2; M0.25: MGO-MFP5 composite coating sample in Example 3; NAOH: coating samples treated with sodium hydroxide in Examples 1, 2, and 3; MG: samples without any treatment in Examples 1, 2, and 3.

[0035] Figure 5 These are the results of the inhibition performance of the MGO-MFP5 composite coating sample against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) verified by the plate count method in the examples; wherein, M1: the MGO-MFP5 composite coating sample in Example 1; M0.5: the MGO-MFP5 composite coating sample in Example 2; M0.25: the MGO-MFP5 composite coating sample in Example 3; NAOH: the coating sample treated with sodium hydroxide in Examples 1, 2, and 3; MG: the sample without any treatment in Examples 1, 2, and 3. DETAILED DESCRIPTION

[0036] In order to more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the following is a further detailed and complete description of the technical effects produced by the present invention in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present invention, and not all of them. It should be pointed out that for those skilled in the art, other embodiments obtained without departing from the concept of the present invention are all within the scope of protection of the present invention.

[0037] Unless otherwise specified in the following examples, all reagents and materials used were commercially available.

[0038] Example 1

[0039] In this embodiment, an MGO-MFP5 composite coating is prepared on the surface of a magnesium alloy, and the steps are as follows:

[0040] (1) Cut the magnesium alloy into thin slices and polish them with 800#, 1200#, 1500#, 2000#, and 3000# sandpaper in sequence until the surface is smooth;

[0041] (2) The polished magnesium alloy was ultrasonically cleaned with anhydrous ethanol and deionized water for 15 minutes, and then dried and labeled as Mg;

[0042] (3) Soak Mg in 5 mol / L sodium hydroxide solution at room temperature for 24 hours (25 ± 2 °C), remove and rinse with deionized water, dry and label as NAOH, and sterilize with UV for 12 hours;

[0043] (4) Dilute MEFP-5 to 0.25-1 mg / mL with Tris buffer and filter sterilize;

[0044] (5) Using the micro-droplet deposition method, 1 mg / mL MEFP-5 solution was coated on the NAOH surface with a coating amount of 0.3-0.5 mL / cm 2 , and dried away from light to form an MGO-MFP5 composite coating.

[0045] Example 2

[0046] The steps are the same as those in Example 1, except that the concentration of MEFP-5 in step (5) is 0.5 mg / mL.

[0047] Example 3

[0048] The steps are the same as those in Example 1, except that the concentration of MEFP-5 in step (5) is 0.25 mg / mL.

[0049] The characterization methods and performance test results are as follows:

[0050] The surface morphology of the samples was characterized by SEM. Figure 1As shown, the MG sample has clear scratches on its surface, which were produced during the sample preparation process. After the NAOH sample was treated with sodium hydroxide, a thin film of MGO formed on its surface, but faint scratches were still visible. Samples M1, M0.5, and M0.25 coated with the MFP-5 solution showed no scratches and clear protein precipitates, demonstrating high coverage of the mussel protein on the NAOH sample surface.

[0051] The samples were immersed in SBF simulated body fluid for 7 days and 14 days to observe the corrosion resistance of MgO film and MGO-MFP5 composite coating on magnesium alloy. Figure 2 As shown in the figure, after 7 days of immersion, the untreated MG sample developed large-scale cracks and shedding on the surface, indicating severe corrosion. The NAOH sample with the MgO film showed no cracks, but exhibited uniform pitting on the surface. The M1, M0.5, and M0.25 samples with the MGO-MFP5 composite coating showed partial cracking, but no pitting or shedding of the coating. After 14 days of immersion, corrosion intensified on the MG sample, with numerous pits forming on the surface and partial corrosion shedding. The NAOH sample with the MgO film showed large cracks, indicating that the MgO film can provide short-term protection but not long-term corrosion resistance. The M1 sample with the MGO-MFP5 composite coating showed only partial cracking, indicating that the MGO-MFP5 composite coating can provide enhanced long-term protection.

[0052] The water contact angle meter is used to characterize the hydrophilicity and hydrophobicity of the sample, such as Figure 3 As shown in the figure, the water contact angle of the NAOH sample with MgO film is lower than that of the untreated MG sample, indicating that the hydrophilicity has been improved. The water contact angles of the M1, M0.5, and M0.25 samples with MGO-MFP5 composite coating are significantly lower than that of the MG sample, indicating that the MGO-MFP5 composite coating has strong hydrophilicity, which is conducive to cell adhesion.

[0053] The cytotoxicity of the samples was tested by live-dead cell staining experiments, such as Figure 4 As shown in the figure, on day 1, the number of cells on the surfaces of the NAOH and MG samples was relatively small and sparsely distributed, while the number of cells on the surfaces of the M1, M0.5, and M0.25 samples coated with the MGO-MFP5 composite coating was slightly higher. By day 3, the number of cells on the surfaces of all samples increased, with the M1 and M0.5 samples showing a more pronounced increase and a denser distribution, indicating improved cell viability. By day 5, the sample coated with the MGO-MFP5 composite coating had the highest number of cells, with a uniform and dense distribution, indicating good cell viability. These results demonstrate that the MGO-MFP5 composite coating has good cytocompatibility and can effectively promote cell proliferation.

[0054] The inhibitory performance of the coating on E. coli and S. aureus was analyzed by plate counting method. Figure 5 As shown in the figure, the MGO-MFP5 composite coating has good antibacterial properties, among which the M1-coated sample has an antibacterial activity against Escherichia coli of 88.37% and an antibacterial activity against Staphylococcus aureus of 92.64%.

[0055] In summary, the MgO-MFP5 composite coating of the present invention cleverly combines the advantages of the MgO film and the MFP5 coating. The MgO film retards corrosion of magnesium alloys and enhances the biocompatibility of magnesium-based materials. The MFP5 coating, leveraging its molecular structure, exhibits strong antibacterial properties and promotes cell adhesion. This composite coating can significantly reduce the incidence of adverse reactions such as bacterial infection and tissue rejection that can occur during clinical use of medical magnesium products, effectively extending their service life and improving their medical effectiveness. It is suitable for common medical magnesium-based bone implants such as bone fixation devices, joint prostheses, and bone screws, and has important clinical application value.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing an MGO-MFP5 composite coating on a magnesium alloy surface, characterized in that: The following steps are involved: (1) Cut the magnesium alloy into thin slices and polish them with 800#, 1200#, 1500#, 2000#, and 3000# sandpaper in sequence until the surface is smooth; (2) The polished magnesium alloy was ultrasonically cleaned with anhydrous ethanol and deionized water in sequence, and then dried and labeled as Mg; (3) Soak Mg in sodium hydroxide solution and let it stand for a while, then take it out and rinse it with deionized water. After drying, mark it as NAOH and sterilize it with ultraviolet light. (4) diluting MEFP-5 with Tris buffer and filtering to sterilize to obtain MEFP-5 solution; (5) The MEFP-5 solution was coated on the NAOH surface by the micro-droplet deposition method and dried in the dark to form the MGO-MFP5 composite coating.

2. The method for preparing the MGO-MFP5 composite coating on the surface of the magnesium alloy according to claim 1, characterized in that: In step (1), the magnesium alloy sheet has a diameter of 15 mm and a thickness of 5 mm.

3. The method for preparing the MGO-MFP5 composite coating on the surface of the magnesium alloy according to claim 1, characterized in that: In step (3), the concentration of the sodium hydroxide solution is 3 to 8 mol / L, the soaking temperature is 23 to 27° C., and the standing time is 12 to 24 hours.

4. The method for preparing the MGO-MFP5 composite coating on the surface of the magnesium alloy according to claim 3, characterized in that: In step (3), the concentration of the sodium hydroxide solution is 5 mol / L, the soaking temperature is 25° C., and the standing time is 24 hours.

5. The method for preparing the MGO-MFP5 composite coating on the surface of the magnesium alloy according to claim 1, characterized in that: In step (4), the concentration of the MEFP-5 solution is 0.25-1 mg / mL.

6. The method for preparing the MGO-MFP5 composite coating on the surface of the magnesium alloy according to claim 1, characterized in that: In step (5), the coating amount of the MEFP-5 solution is 0.3 to 0.5 mL / cm 2 .

7. A MGO-MFP5 composite coating on a magnesium alloy surface, characterized in that: The composite coating is prepared by the method for preparing the MGO-MFP5 composite coating on the surface of the magnesium alloy according to any one of claims 1 to 6, and comprises an MgO film layer and an MFP5 coating sequentially covering the surface of the magnesium alloy.

8. A magnesium alloy material containing an MGO-MFP5 composite coating, characterized in that: It comprises the MGO-MFP5 composite coating on the surface of the magnesium alloy as claimed in claim 7.

9. Use of the MGO-MFP5 composite coating on the surface of the magnesium alloy according to claim 8, or the magnesium alloy material containing the MgO-MFP5 composite coating according to claim 7, in the preparation of magnesium-based bone implants with antibacterial and cell proliferation promoting effects.

10. The use according to claim 9, characterized in that The magnesium-based bone implant includes a bone fixation device, a cardiovascular stent or a bone trauma repair material.

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