Inorganic-organic composite coating on zinc or zinc alloy surface, preparation method and zinc alloy

Abstract

The invention relates to the field of metal material surface treatment and the field of zinc alloy biological material surface modification, and provides a zinc or zinc alloy surface inorganic-organic composite coating, a preparation method and a zinc alloy, the preparation method comprises the following steps: S1, pre-treating a zinc and zinc alloy sample, and carrying out micro-arc oxidation on the surface of the zinc and zinc alloy sample to form a porous structure; s2, MPN (metal-polyphenol network) coating modification is performed on the porous structure surface of the zinc and zinc alloy sample treated in the step S1, and the inorganic-organic composite coating on the zinc and zinc alloy surface is obtained. According to the invention, tannic acid and Zn < 2 + > on the surface of the porous micro-arc oxidation coating on the surface of zinc and zinc alloy are self-assembled to guide a metal-polyphenol network coating to form an inorganic-organic composite coating on the surface of the micro-arc oxidation porous implant coating, so that the problems of unstable degradation rate of zinc and zinc alloy and initial inflammation outbreak generally existing in various implants are solved; the preparation method is simple, and materials are easy to obtain.

Description

Technical Field

[0001] This invention relates to the fields of surface treatment of metallic materials and surface modification of zinc alloy biomaterials, and particularly to an inorganic-organic composite coating for zinc or zinc alloy surfaces, a preparation method thereof, and the zinc alloy itself. Background Technology

[0002] Biodegradable medical zinc and zinc alloys have attracted widespread attention as implantable materials for medical devices in recent years due to their good biocompatibility and mechanical properties. However, zinc and zinc alloys are prone to cytotoxicity in the early stages of implantation due to the sudden release of zinc ions from the surface, and their degradation is too slow in the later stages, resulting in an unstable surface microenvironment during implantation. Therefore, surface modification of zinc and zinc alloys to stabilize their degradation rate is extremely important. Among surface modification methods, micro-arc oxidation (MAO) technology forms a highly adhesive coating in situ on the substrate surface based on pulsed voltage, which stabilizes the substrate surface microenvironment, and its porous structure can improve the biocompatibility of the implant.

[0003] Furthermore, any implantation procedure can induce inflammation, largely due to a surge in local reactive oxygen species (ROS) caused by changes in the microenvironment. ROS stimulate macrophages to hyperpolarize into the pro-inflammatory M1 form, releasing more inflammatory factors and ROS, creating a vicious cycle of persistent oxidative stress and exacerbating the inflammatory storm. Therefore, enabling implants to respond to inflammation is crucial for alleviating patient suffering.

[0004] Currently, there is no surface modification method that simultaneously stabilizes the degradation rate of zinc and zinc alloys and provides self-responsive inflammation after implantation. Therefore, developing a surface modification method that combines both properties is a key focus for advancing the clinical application of zinc and zinc alloys as implants. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical problem in the prior art of not having both stable zinc and zinc alloy degradation rates and surface modification that provides self-responsive inflammation after implantation, and to provide an inorganic-organic composite coating for zinc or zinc alloy surfaces, a preparation method, and a zinc alloy.

[0006] The present invention adopts the following technical solution:

[0007] On one hand, the present invention provides a method for preparing an inorganic-organic composite coating on the surface of zinc or zinc alloys, comprising:

[0008] S1. Zinc or zinc alloy sample pretreatment: Micro-arc oxidation (MAO) treatment is performed on the surface of zinc or zinc alloy samples to form an inorganic oxide film on the surface of zinc or zinc alloy samples, and at the same time, a porous structure is formed.

[0009] S2. The porous surface of the zinc or zinc alloy sample treated in step S1 is modified with an MPN coating to obtain an inorganic-organic composite coating on the zinc or zinc alloy surface.

[0010] In addition to any of the possible implementations described above, another implementation is provided, wherein step S1 specifically includes:

[0011] S1.1 Sample surface pretreatment: Mechanical grinding, cleaning, and drying of the sample surface;

[0012] S1.2 Micro-arc oxidation (MAO) treatment: A pulsed power supply with zinc sheet as anode and stainless steel plate as cathode is used. An aqueous solution of sodium hydroxide and hydrated glycerol phosphate is used as electrolyte. The sample pretreated in step S1.1 is treated with MAO at the set pulse frequency, duty cycle, voltage and current. After drying, an inorganic coating Zn_MAO is obtained.

[0013] In addition to any of the possible implementations described above, another implementation is provided, wherein the specific method of step S2 is as follows:

[0014] S2.1 Anhydrous zinc sulfate (ZnSO4) and tannic acid (TA) solution are added to an aqueous solution and vigorously mixed to obtain a first mixed solution; then NaOH is added to raise the pH of the mixed solution to slightly alkaline to obtain a second mixed solution containing MPN (metal-polyphenol network) structural units.

[0015] It should be noted that the MPN structural unit can only be obtained in the mixed solution under slightly alkaline conditions (e.g., pH=8).

[0016] S2.2 The sample treated in step S1 is placed in the second mixed solution containing MPN structural units and reacted for a period of time. Then the sample is taken out, rinsed, and dried to obtain the inorganic-organic composite coating Zn_MAO_MPN on the surface of zinc or zinc alloy.

[0017] The metal-polyphenol mesh coating is obtained by self-assembly of ROS-sensitive tannic acid and zinc ions through chelation, wherein the molar ratio of ROS-sensitive tannic acid to zinc ions is 1:1.

[0018] Based on tannic acid (TA), MPNs can be programmed to change macrophages from pro-inflammatory M1 type to anti-inflammatory M2 type by leveraging TA's ROS scavenging function, thus enabling them to respond automatically to inflammation.

[0019] In addition to any of the possible implementations described above, another implementation is provided in which, in step S2.2, the sample is rinsed and dried, then placed back into the second mixed solution to react for a period of time, and then the sample is taken out and rinsed and dried again; this is repeated 1-5 times to obtain the inorganic-organic composite coating Zn_MAO_MPN on the surface of the zinc or zinc alloy.

[0020] In addition to any of the possible implementations described above, another implementation is provided in which, in step S1.1, the sample is continuously mechanically ground with SiC paper with a particle size ranging from 800 to 2000, then ultrasonically cleaned in acetone, anhydrous alcohol, and deionized water for 10-15 minutes each, and dried at room temperature.

[0021] In addition to any of the possible implementations described above, another implementation is provided in which, in step S1.2, the pulse frequency of the MAO processing is 300Hz to 700Hz, the duty cycle is 15% to 30%, the voltage is 200V to 450V, and the current is 1.0A to 2.0A.

[0022] In addition to any of the possible implementations described above, another implementation is provided in which, in step S2.1, ZnSO4 and TA solutions are added to water, and the solutions are vigorously mixed for 10±5s using a vortex mixer to form a first mixed solution.

[0023] In addition to any of the possible implementations described above, a further implementation is provided in which the final concentration of ZnSO4 in the first mixed solution is 0.1 ± 0.02 mg / ml and the final concentration of TA is 0.1 ± 0.02 mg / ml.

[0024] On the other hand, the present invention also provides an inorganic-organic composite coating on the surface of zinc or zinc alloy, wherein the inorganic-organic composite coating on the surface of zinc or zinc alloy is obtained by the above-mentioned preparation method of inorganic-organic composite coating on the surface of zinc or zinc alloy.

[0025] In another aspect, the present invention also provides a zinc alloy, wherein the surface of the zinc alloy is modified with the above-mentioned inorganic-organic composite coating on the zinc or zinc alloy surface.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. This invention utilizes ROS-responsive TA and Zn 2+ The self-assembly of porous MAO coatings on the surface guides the formation of an inorganic-organic composite coating of MPN coatings on the surface of porous implant MAO coatings. The preparation method is simple and easy to implement, and the materials are safe and readily available.

[0028] 2. The inorganic coating MAO on the surface of zinc and zinc alloy prepared by this invention has good bonding performance with the substrate, is not easy to fall off, and stabilizes the degradation of zinc and zinc alloy implants.

[0029] 3. The organic coating prepared by this invention can utilize the ROS response of TA to clear ROS after implantation, thereby alleviating inflammation caused by the surge of local reactive oxygen species (ROS) and achieving the purpose of self-responding to inflammation.

[0030] 4. The modification method of inorganic-organic composite coating on zinc and zinc alloy surfaces proposed in this invention has the same metal ions as the degradation products of zinc and zinc alloy substrates and inorganic-organic composite coatings, so as to achieve a high zinc ion environment on the substrate, slow down the decomposition of organic coatings, and achieve ROS removal effect during the inflammatory outbreak stage (the first two weeks after implantation). Attached Figure Description

[0031] Figure 1 SEM images of the inorganic coating on the zinc surface in Example 1: (a) SEM image of the micron-sized porous structure on the zinc surface; (b) a magnified view of the SEM image of the micron-sized porous structure on the zinc surface; (c) a cross-sectional morphology scanning SEM image of the micron-sized porous structure on the zinc surface.

[0032] Figure 2 For comparative example 1, SEM images of the inorganic coating on the zinc surface under different voltages are shown. The coating cracks are marked with wireframes: (a) and (b) are SEM images at different magnifications under a voltage of 200V; (c) and (d) are SEM images at different magnifications under a voltage of 300V.

[0033] Figure 3 The image shows the XPS image of the inorganic-organic composite coating on the zinc surface obtained in Example 2.

[0034] Figure 4 SEM images of Zn, Zn_MAO obtained in Example 1, Zn_MPN obtained in Comparative Example 2, and Zn_MAO_MPN obtained in Example 2: (a) and (e) are SEM images of Zn at different magnifications; (b) and (f) are SEM images of Zn_MAO at different magnifications; (c) and (g) are SEM images of Zn_MPN at different magnifications; (d) and (h) are SEM images of Zn_MAO_MPN at different magnifications.

[0035] Figure 5 The image shown is a DPPH removal diagram of the inorganic-organic composite coating on the zinc surface in Example 2.

[0036] Figure 6 The diagram shown is a flowchart illustrating a method for preparing an inorganic-organic composite coating on the surface of zinc or zinc alloy according to an embodiment of the present invention. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered in isolation, but can be combined with each other to achieve better technical effects.

[0038] like Figure 6 As shown in the embodiment of the present invention, a method for preparing an inorganic-organic composite coating on a zinc or zinc alloy surface includes:

[0039] S1. Zinc or zinc alloy sample pretreatment: Micro-arc oxidation (MAO) treatment is performed on the surface of zinc or zinc alloy samples to form an inorganic oxide film on the surface of zinc or zinc alloy samples, and at the same time, a porous structure is formed.

[0040] S2. The porous surface of the zinc or zinc alloy sample treated in step S1 is modified with an MPN coating to obtain an inorganic-organic composite coating on the zinc or zinc alloy surface.

[0041] In one specific embodiment, step S1 specifically includes:

[0042] S1.1 Sample surface pretreatment: Mechanical grinding, cleaning, and drying of the sample surface;

[0043] S1.2 Micro-arc oxidation (MAO) treatment: A pulsed power supply with zinc sheet as anode and stainless steel plate as cathode is used. An aqueous solution of sodium hydroxide and hydrated glycerol phosphate is used as electrolyte. The sample pretreated in step S1.1 is treated with MAO at the set pulse frequency, duty cycle, voltage and current. After drying, an inorganic coating Zn_MAO is obtained.

[0044] In one specific embodiment, the method for step S2 is as follows:

[0045] S2.1 Anhydrous zinc sulfate (ZnSO4) and tannic acid (TA) solution are added to an aqueous solution and vigorously mixed to obtain a first mixed solution; then NaOH is added to raise the pH of the mixed solution to slightly alkaline to obtain a second mixed solution containing MPN structural units.

[0046] S2.2 The sample treated in step S1 is placed in the second mixed solution containing MPN structural units and reacted for a period of time. Then the sample is taken out, rinsed, and dried to obtain the inorganic-organic composite coating Zn_MAO_MPN on the surface of zinc or zinc alloy.

[0047] In one specific embodiment, in step S2.2, after the sample is rinsed and dried, it is placed in the second mixed solution again for a period of time, and then the sample is taken out and rinsed and dried again; this process is repeated 1-5 times to obtain the inorganic-organic composite coating Zn_MAO_MPN on the surface of zinc or zinc alloy.

[0048] In one specific embodiment, in step S1.1, the sample is continuously mechanically ground with SiC paper with a particle size ranging from 800 to 2000, then ultrasonically cleaned in acetone, anhydrous alcohol and deionized water for 10-15 minutes each, and dried at room temperature.

[0049] In one specific embodiment, in step S1.2, the pulse frequency of the MAO processing is 300Hz to 700Hz, the duty cycle is 15% to 30%, the voltage is 200V to 450V, and the current is 1.0A to 2.0A.

[0050] In one specific embodiment, in step S2.1, ZnSO4 and TA solutions are added to water, and the solutions are vigorously mixed for 10±5s using a vortex mixer to form a first mixed solution.

[0051] In one specific embodiment, the final concentration of ZnSO4 in the first mixed solution is 0.1 ± 0.02 mg / ml, and the final concentration of TA is 0.1 ± 0.02 mg / ml.

[0052] This invention provides an inorganic-organic composite coating for the surface of zinc or zinc alloys, wherein the inorganic-organic composite coating for the surface of zinc or zinc alloys is obtained by the above-described preparation method for inorganic-organic composite coatings for the surface of zinc or zinc alloys.

[0053] This invention relates to a zinc alloy, wherein the surface of the zinc alloy is modified with an inorganic-organic composite coating as described above.

[0054] Example 1

[0055] The preparation of an inorganic micro-arc oxidation coating on a pure zinc surface includes the following steps:

[0056] (1) First, the zinc sheet (Zn, Φ5×2mm) sample was continuously mechanically ground with SiC paper with a particle size from 800 to 2000. Then, it was ultrasonically cleaned in acetone, anhydrous alcohol and deionized water for 10 minutes each and dried at room temperature.

[0057] (2) A pulsed power supply was used with the zinc sheet obtained above as the anode and the stainless steel plate as the cathode. The electrolyte consisted of 2.5 g / L sodium hydroxide and 0.02 mol / L hydrated calcium glycerophosphate dissolved in deionized water. The pulse frequency was fixed at 500 Hz and the duty cycle was set to approximately 30%. A voltage of 330 V was applied and the treatment was carried out for 3 min. Subsequently, all samples were washed with water and dried to obtain Zn_MAO.

[0058] The surface morphology of Zn_MAO was obtained by SEM. Figure 1 As can be seen from (a) and (b) at different magnifications, the porous structure of the foam is shown in (c). The coating is tightly bonded to the substrate and has sufficient thickness, indicating that the MAO coating has been successfully synthesized on the Zn surface.

[0059] Example 2

[0060] The process of applying an MPN coating to the surface of a Zn_MAO porous structure includes the following steps:

[0061] (1) Add anhydrous zinc sulfate (ZnSO4) and tannic acid (TA) solution to the aqueous solution and mix vigorously for 10 seconds to form a first mixed solution of 40 ml with the concentration of both substances being 0.1 mg / ml; then add 330 μl of NaOH solution (1 g / L) to raise the pH of the mixed solution to about 8 to obtain the MPN structural unit, and then rinse with water and dry.

[0062] (2) Place the Zn_MAO sample obtained above into a solution containing MPN structural units, evacuate for 2 minutes, take it out and dry it to complete the first coating on the front side. Repeat the above steps three times on the back side as well, layer by layer, to obtain Zn_MAO_MPN.

[0063] The absorption peaks and elemental variations of Zn_MAO_MPN and Zn_MAO were analyzed using XPS. Figure 3 As can be seen, Zn_MAO_MPN contains a C=O peak while Zn_MAO does not. This C=O peak is contained in the TA in MPN, indicating that the MPN coating in Zn_MAO_MPN was successfully constructed on the inorganic coating.

[0064] And through Figure 4 SEM image analysis shows that the MPN coating of Zn_MAO_MPN has better continuity.

[0065] Comparative Example 1

[0066] The preparation of Zn_MAO differs from that in Example 1 in that the 330V voltage applied in step (2) is replaced with 200V and 300V respectively, while the other steps and parameters are the same as in Example 1.

[0067] The surface morphology of samples under different voltages was obtained by SEM, such as Figure 2 As shown in (a) and (c), it can be seen that the coating exhibits obvious cracks at voltages of 200 and 300V, while the coating density is lower at lower voltages. Figure 1 (a) shows no obvious cracks and has high density. With increasing voltage, the sample surface is broken down by the high voltage, resulting in black spots. Furthermore, (b) and (d) show that the size and density of the porous structure produced by different voltages are different.

[0068] Comparative Example 2

[0069] The preparation of Zn_MPN differs from that in Example 2 in that the sample used in step (2) is replaced with the Zn obtained in Example 1 (1).

[0070] Effect:

[0071] The oxygen radical DPPH model was used to detect the strength of ROS scavenging ability. An in vitro ROS scavenging ability experiment was conducted on an inorganic-organic composite coating (Zn_MAO_MPN) on a zinc surface.

[0072] Zn, Zn_MAO obtained in Example 1, Zn_MPN obtained in Comparative Example 2, and Zn_MAO_MPN obtained in Example 2 were placed in 48-well plates and immersed in 1 mL of PBS to simulate a body fluid environment. Five parallel wells were set up, and the samples were co-cultured at 37°C for 1, 5, 15, 25, and 28 days. After co-culturing, the samples were removed, washed with deionized water and ethanol, and dried. They were then placed in 96-well plates, and 200 μL of 0.1 mM DPPH was added. The plates were co-cultured in the dark at 37°C for 30 min. Simultaneously, 200 μL of the solution was added to three blank wells as a control group. After co-culturing, 100 μL was taken from each well and added to a new 96-well plate. The absorbance of each well was measured using a microplate reader, and the calculation formula is as follows:

[0073] DPPH clearance rate (%) = (Ac - As) / Ac × 100%

[0074] In the formula, Ac is the absorbance of the blank control containing only DPPH solution, and As is the absorbance of the DPPH solution in the presence of the sample.

[0075] like Figure 5 As shown, the Zn_MAO_MPN group had a higher DPPH clearance rate than the other three groups, and still had half of its original clearance capacity after 28 days, indicating that the Zn_MAO_MPN group has long-term ROS clearance capacity.

[0076] This invention solves the problems of unstable degradation rate of zinc and zinc alloys and the initial inflammatory outbreak that is common in various implants. Moreover, the preparation method is simple and the materials are readily available.

[0077] While several embodiments of the present invention have been provided herein, those skilled in the art should understand that modifications can be made to these embodiments without departing from the spirit of the invention. The above embodiments are merely exemplary and should not be construed as limiting the scope of the invention.

Claims

1. A method for preparing an inorganic-organic composite coating on the surface of zinc or zinc alloy, characterized in that, The method includes: S1. Zinc or zinc alloy sample pretreatment: Micro-arc oxidation (MAO) treatment is performed on the surface of zinc or zinc alloy samples to form an inorganic oxide film on the surface of zinc or zinc alloy samples, and at the same time, a porous structure is formed. S2. The porous surface of the zinc or zinc alloy sample treated in step S1 is modified with an MPN coating to obtain an inorganic-organic composite coating on the zinc or zinc alloy surface.

2. The method for preparing an inorganic-organic composite coating on the surface of zinc or zinc alloy as described in claim 1, characterized in that, Step S1 specifically includes: S1.1 Sample surface pretreatment: Mechanical grinding, cleaning, and drying of the sample surface; S1.2 Micro-arc oxidation (MAO) treatment: A pulsed power supply with zinc sheet as anode and stainless steel plate as cathode is used. An aqueous solution of sodium hydroxide and hydrated glycerol phosphate is used as electrolyte. The sample pretreated in step S1.1 is treated with MAO at the set pulse frequency, duty cycle, voltage and current. After drying, an inorganic coating Zn_MAO is obtained.

3. The method for preparing an inorganic-organic composite coating on the surface of zinc or zinc alloy as described in claim 1, characterized in that, The specific method for step S2 is as follows: S2.1 Anhydrous zinc sulfate (ZnSO4) and tannic acid (TA) solution are added to water and vigorously mixed to obtain a first mixed solution; then NaOH is added to raise the pH of the mixed solution to slightly alkaline to obtain a second mixed solution containing MPN structural units. S2.2 The sample treated in step S1 is placed in the second mixed solution containing MPN structural units and reacted for a period of time. Then the sample is taken out, rinsed, and dried to obtain the inorganic-organic composite coating Zn_MAO_MPN on the surface of zinc or zinc alloy.

4. The method for preparing an inorganic-organic composite coating on a zinc or zinc alloy surface as described in claim 3, characterized in that, In step S2.2, after rinsing and drying, the sample is placed in the second mixed solution again for a period of time, and then the sample is taken out and rinsed and dried again; this process is repeated 1-5 times to obtain the inorganic-organic composite coating Zn_MAO_MPN on the surface of zinc or zinc alloy.

5. The method for preparing an inorganic-organic composite coating on a zinc or zinc alloy surface as described in claim 2, characterized in that, In step S1.1, the sample is continuously mechanically ground with SiC paper with a particle size ranging from 800 to 2000, then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 10-15 minutes each, and dried at room temperature.

6. The method for preparing an inorganic-organic composite coating on a zinc or zinc alloy surface as described in claim 2, characterized in that, In step S1.2, the pulse frequency of the MAO process is 300Hz to 700Hz, the duty cycle is 15% to 30%, the voltage is 200V to 450V, and the current is 1.0A to 2.0A.

7. The method for preparing the inorganic-organic composite coating on the zinc alloy surface as described in claim 3, characterized in that, In step S2.1, ZnSO4 and TA solution are added to water, and the solution is vigorously mixed for 10±5s using a vortex mixer to form the first mixed solution.

8. The method for preparing an inorganic-organic composite coating on a zinc or zinc alloy surface as described in claim 7, characterized in that, In the first mixed solution, the final concentration of ZnSO4 is 0.1±0.02 mg / ml, and the final concentration of TA is 0.1±0.02 mg / ml.

9. An inorganic-organic composite coating for the surface of zinc or zinc alloy, characterized in that, The inorganic-organic composite coating on the zinc or zinc alloy surface is obtained by the preparation method of the inorganic-organic composite coating on the zinc or zinc alloy surface as described in any one of claims 1-8.

10. A zinc alloy, characterized in that, The zinc alloy is surface-modified with the inorganic-organic composite coating on the zinc or zinc alloy surface as described in claim 9.

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