A substrate with micro-nano composite texture and a preparation method and application thereof

Abstract

The application relates to a substrate with micro-nano composite texture and a preparation method and application thereof, and belongs to the technical field of biological medicine. The preparation method comprises the following steps: S1, adopting a nanosecond laser to perform texture treatment on pretreated metal titanium, forming micro texture on the surface of the metal titanium, and obtaining micro texture metal titanium; S2, uniformly stirring ammonium fluoride in ethylene glycol, then uniformly stirring water in the ethylene glycol, and obtaining an electrolyte; S3, connecting the positive pole of a direct current power supply to the micro texture metal titanium as an anode, connecting the negative pole of the direct current power supply to a platinum electrode as a cathode, and performing magnetic field assisted anodic oxidation treatment on the micro texture metal titanium in the electrolyte, so that nano texture is formed on the surface of the micro texture metal titanium; and after cleaning and drying, a substrate with micro-nano composite texture is obtained. The substrate is applied to a drug-loaded coating of a metal implant, can realize micro-nano multi-scale cooperation, integrates the macrostructure advantage of the micron texture and the surface characteristics of the nanotube, and greatly improves the comprehensive performance of the drug-loaded coating.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, and in particular relates to a substrate with micro-nano composite texture, its preparation method and application. Background Technology

[0002] In the biomedical field, drug-loaded coatings are widely used in implantable medical devices such as orthopedic implants and cardiovascular stents. By loading therapeutic drugs onto the surface of the device, local drug delivery can be achieved, effectively reducing the side effects of systemic administration. However, traditional methods for preparing drug-loaded coatings have many limitations, namely, low drug loading and difficulty in controlling the release rate, often resulting in "burst release." Additionally, the coating has weak adhesion to the substrate, is prone to detachment, and has a simple structure that cannot meet complex therapeutic needs.

[0003] Micro-nano composite textures, with their unique multi-level structure, provide an ideal carrier platform for drug-loaded coatings. Preparing micron- or nano-scale textures on the surface of metal implants can improve cell affinity, promote cell proliferation, and reduce the risk of implant-induced inflammation. However, existing methods for preparing micro-nano composite textures still have their own drawbacks: for example, while traditional anodizing can fabricate tubular nanotextures on metal surfaces, it suffers from difficulties in controlling tube diameter, length, and arrangement; insufficient bonding strength between nanotubes and the substrate; and low processing efficiency. Especially in the ethylene glycol-ammonium fluoride electrolyte system, the formation of nanotubes on titanium surfaces depends on the dynamic balance between the slow corrosion of the titanium surface by fluoride ions in the electrolyte and the oxidation reaction. This process requires a long reaction period to form nanotube arrays with specific lengths and masses. Especially when preparing deeper and longer nanotubes, the oxidation time often takes several hours or even tens of hours. Such a lengthy oxidation process not only significantly increases preparation costs and severely restricts production efficiency but also leads to uneven nanotube growth. While laser etching microtexturing technology can precisely prepare micron-scale patterns on metal surfaces, it can only change the geometry and roughness of the metal surface. In the biomedical field, the interaction between cells and material surfaces is not only determined by surface morphology, but is also affected by multiple factors such as surface chemical composition and charge properties. Although this technology can improve the surface roughness of titanium and reduce its hydrophobicity, improper hydrophobicity control can still easily lead to excessive hydrophobicity of the surface, thereby weakening the cell affinity and biological activity of the metal surface and deteriorating its biocompatibility.

[0004] Therefore, developing a substrate with micro-nano composite texture that can solve the above problems and its preparation method is of great practical significance. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of poor biocompatibility of laser etching microtexture processing in the prior art, insufficient growth uniformity and low preparation efficiency of titanium nanotubes, and weak film-substrate bonding strength of drug-loaded coatings.

[0006] To address the aforementioned technical problems, this invention provides a substrate with micro / nano composite textures, its preparation method, and its applications. First, a nanosecond laser is used to construct a microtexture on the surface of metallic titanium, thereby increasing the specific surface area and surface energy of the substrate. Then, through a magnetic field-assisted anodizing process, titanium nanotubes are grown in situ on the surface of the microtextured titanium to form a nanotexture, ultimately achieving the controllable preparation of micro / nano composite textures suitable for drug-loaded coatings. The preparation of the microtexture provides a structured substrate for the subsequent growth of the nanotexture. Its high specific surface area not only enhances the loading capacity of titanium nanotubes, but the increased surface energy also strengthens the interfacial bonding between the titanium nanotubes and the substrate. Furthermore, the introduction of the magnetic field-assisted mechanism accelerates the growth of F... - Transport to the titanium / titanium oxide interface and promote [TiF6] transport. 2- Removing the substrate from the interface region avoids the formation of concentration gradients due to ion consumption or product accumulation at the bottom and near the pores of titanium nanotubes, making the anodic oxidation reaction more uniform. This effectively improves the growth uniformity of titanium nanotubes and significantly enhances their preparation efficiency, laying a key structural foundation for the high performance of the substrate.

[0007] The first objective of this invention is to provide a method for preparing a substrate with a micro-nano composite texture, comprising the following steps:

[0008] S1. Texturization treatment of pretreated metallic titanium is performed using nanosecond laser to form microtextures on the surface of metallic titanium, resulting in microtextured metallic titanium.

[0009] S2. Add ammonium fluoride to ethylene glycol and stir until homogeneous. Then add water and continue stirring until homogeneous to obtain the electrolyte.

[0010] S3. Connect the microtextured titanium metal described in S1 to the positive terminal of a DC power supply as the anode and the platinum electrode to the negative terminal of a DC power supply as the cathode. Perform magnetic field-assisted anodic oxidation treatment in the electrolyte described in S2 to form a nanotexture on the surface of the microtextured titanium metal. After ultrasonic cleaning and natural drying, the substrate with the micro-nano composite texture is obtained.

[0011] In one embodiment of the present invention, in S1, the pretreated titanium metal is obtained by grinding, polishing and cleaning titanium metal.

[0012] In one embodiment of the present invention, in S1, the processing parameters of the texturing process are: laser pulse power of 1W-10W, frequency of 100kHz-500kHz, pulse width of 10ns-15ns, and scanning speed of 20mm / s-200mm / s.

[0013] In one embodiment of the present invention, in S1, the dimensions of the microtexture are: a depth of 10μm-50μm, a width of 50μm-150μm, and a spacing of 100μm-200μm.

[0014] In one embodiment of the present invention, in S2, the concentration of ammonium fluoride in the electrolyte is 3 mg / mL-5 mg / mL, and the volume ratio of ethylene glycol to water is (8.8-9.2):1.

[0015] In one embodiment of the present invention, in S3, the magnetic field assistance is achieved by applying a magnetic field of 0.12T-0.18T perpendicular to the electric field direction through a ring-shaped permanent magnet.

[0016] In one embodiment of the present invention, in S3, the processing parameters for the anodizing treatment are: voltage of 20V-40V and time of 1h-2h.

[0017] In one embodiment of the present invention, in S3, the dimensions of the nanotexture are: tube diameter of 90nm-120nm, wall thickness of 15nm-20nm, and length of 8µm-15µm.

[0018] In one embodiment of the present invention, in S3, the ultrasonic cleaning is performed in anhydrous ethanol for 4-6 minutes.

[0019] And / or, the natural drying is to air dry in a ventilated place for 1-2 hours.

[0020] A second objective of this invention is to provide a substrate with a micro-nano composite texture prepared by the method.

[0021] A third objective of this invention is to provide an application of a substrate with a micro-nano composite texture in a drug-loaded coating.

[0022] The technical solution of the present invention has the following advantages compared with the prior art:

[0023] (1) The preparation method of the present invention initiates the anodic oxidation reaction under a specific voltage. The titanium atoms at the anode lose electrons and undergo oxidation, combining with oxygen ions in the electrolyte to form titanium oxide. Driven by the electric field, fluoride ions in the electrolyte migrate towards the anode, causing nanoscale pores to gradually form on the surface of the titanium metal. As the reaction continues, the pores further develop into an ordered array of titanium nanotubes. At the same time, an external magnetic field perpendicular to the direction of the electric field is introduced during the anodic oxidation process. The Lorentz force acts on the charged particles in the electrolyte, thereby inducing magnetohydrodynamic convection and forming "micro-eddies". This effect works synergistically with the electric field to significantly reduce the static diffusion layer on the electrode surface, which on the one hand can accelerate the F - The etchant is continuously and uniformly delivered to the reaction front, while the [TiF6] generated during dissolution is rapidly removed. 2- This not only prevents the accumulation of bubbles in the pores, but also accelerates the detachment of bubbles from the electrode surface, reducing the bubble shielding effect to prevent defects such as pinholes. It not only effectively promotes the homogenization of ion concentration in the interface region and optimizes the morphology of titanium nanotubes, improving their growth uniformity, growth kinetics and structural order, but also significantly improves the growth rate and preparation efficiency of titanium nanotubes.

[0024] (2) The preparation method described in this invention combines laser processing technology with magnetic field-assisted anodizing technology to construct a micro-nano composite texture on the surface of metallic titanium. Laser processing thermally oxidizes the metallic titanium to form a titanium oxide layer several micrometers thick. This titanium oxide layer exhibits a thickness gradient due to the microtexture, and the non-stoichiometric titanium oxide layer formed on the surface of the microtexture contains a large number of oxygen vacancies and interstitial titanium atoms. Its porous structure can serve as a highly efficient ion transport channel, significantly accelerating the ion transport process. - The diffusion process into the titanium substrate; the roots of the titanium nanotubes generated by subsequent anodizing will be embedded in the recessed areas of the microtexture, forming a nested structure of "micro-pit-nanotube"; this structure allows the nanotube array to grow laterally at the edge of the micropit and hook into adjacent textures to form a network of mechanical connections in the lateral direction; in the longitudinal direction, because the depth of the micropit is hundreds of times the length of the nanotube, the bottom of the nanotube is "locked" at the bottom of the pit to resist the vertical peeling force. This micro-anchoring structure can significantly improve the mechanical bonding force between the titanium nanotube and the titanium substrate and prevent the subsequent drug-loaded coating from falling off. Meanwhile, this micro-nano composite texture, relying on the synergistic effect of micro-nano technology, not only further enhances coating adhesion through multi-scale mechanical interlocking structures, but also significantly optimizes interfacial stress distribution and greatly increases the specific surface area of ​​the material. Furthermore, the titanium nanotube nanotexture based on the microtexture can enhance the hydrophilicity of the material surface, placing the surface in a more suitable moderately hydrophilic state for cell growth, thereby promoting cell proliferation and improving the biocompatibility of the material. The high aspect ratio pore structure of the nanotubes can also restrict the Brownian motion of drug molecules, giving the coating excellent drug release kinetics, effectively solving the problems of low drug loading, difficult release rate control, and easy "burst release" in traditional drug-loaded coatings.

[0025] (3) The substrate with micro-nano composite texture described in this invention is applied to the drug-loaded coating of metal implants. Through the synergistic effect of micro-nano multi-scale, it integrates the macroscopic structural advantages of micron texture with the surface characteristics of nanotubes, which greatly improves the comprehensive performance of the drug-loaded coating. It has important application value in the field of drug-loaded coatings for biomedical implantable medical devices. Attached Figure Description

[0026] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the magnetic field-assisted anodizing process of the present invention;

[0028] Figure 2 The images show the surface FESEM morphology and EDS elemental analysis of the substrate in Embodiment 1 of the present invention; wherein, (A) is the FESEM morphology image, (B) is the EDS elemental mapping image, and (C) is the EDS energy spectrum analysis image.

[0029] Figure 3 The following are the surface FESEM morphology and EDS elemental analysis diagrams of the substrate of Comparative Example 1 of the present invention; wherein, (A) is the FESEM morphology diagram, (B) is the EDS elemental mapping diagram, and (C) is the EDS energy spectrum analysis diagram.

[0030] Figure 4 The following are the surface FESEM morphology and EDS elemental analysis diagrams of the substrate of Comparative Example 2 of the present invention; wherein, (A) is the FESEM morphology diagram, (B) is the EDS elemental mapping diagram, and (C) is the EDS energy spectrum analysis diagram.

[0031] Figure 5 The cross-sectional morphology and EDS elemental analysis diagram of the drug-loaded coating prepared on the substrate of Comparative Example 1 of this invention are shown.

[0032] Figure 6 The cross-sectional morphology and EDS elemental analysis diagram of the drug-loaded coating prepared on the substrate of Comparative Example 2 of this invention are shown.

[0033] Figure 7 The cross-sectional morphology and EDS elemental analysis diagram of the drug-loaded coating prepared on the substrate of Example 1 of the present invention are shown.

[0034] Figure 8 The cross-sectional morphology and EDS elemental analysis diagram of the drug-loaded coating prepared on the substrate in Example 2 of this invention are shown.

[0035] Figure 9 This is a comparative analysis of the thickness and drug loading of drug-loaded coatings prepared on different substrates according to the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0037] In this invention, unless otherwise stated, the diamond polishing agent used in the embodiments of this invention was purchased from Jiashan Naibo Precision Instruments Co., Ltd., and the model is PG-DSP0.25.

[0038] Example 1

[0039] The substrate with micro-nano composite texture and its preparation method in this embodiment specifically include the following steps:

[0040] S1. Surface pretreatment: The titanium metal was successively ground with 80#, 200#, 500#, 800#, 1500#, and 2000# sandpaper until there were no obvious scratches on the sample surface. Then, the sample was fixed on a grinding and polishing machine, and polishing was continued with a polishing cloth and diamond polishing agent to achieve a mirror finish. Finally, the polished titanium metal was ultrasonically cleaned in ethanol for 15 minutes to complete the surface pretreatment and obtain pretreated titanium metal.

[0041] S2. Texture treatment: The pretreated titanium metal is textured using an ultraviolet nanosecond laser to induce the formation of microtextures on its surface with a depth of approximately 10 μm, a width of approximately 100 μm, and a spacing of approximately 125 μm, resulting in microtextured titanium metal. The processing parameters for the texture treatment are: laser pulse power of 4W, frequency of 250kHz, pulse width of 13ns, and scanning speed of 20mm / s.

[0042] S3. Electrolyte preparation: Add 0.3g of ammonium fluoride granules to a beaker containing 90mL of ethylene glycol, stir magnetically for 40min, then add 10mL of deionized water and continue stirring magnetically for 20min to obtain the electrolyte.

[0043] S4, Magnetic field-assisted anodizing treatment ( Figure 1 Electrolyte was injected into an electrolytic cell. Microtextured titanium was connected to the positive terminal of a DC power supply as the anode, and a platinum electrode was connected to the negative terminal of a DC power supply as the cathode. A magnetic field of 0.15T perpendicular to the electric field direction was applied, and the microtextured titanium was anodized for 1 hour under a voltage of 20V. Titanium nanotubes with a diameter of about 117nm, a wall thickness of about 15nm, and a length of about 9µm were grown in situ on the surface of the microtexture to form a nanotexture. After the oxidation treatment, it was ultrasonically cleaned in anhydrous ethanol for 5 minutes, and then air-dried in a ventilated place for 1.5 hours to obtain a titanium coating with a micro-nano composite texture.

[0044] Example 2

[0045] The substrate with micro-nano composite texture and its preparation method in this embodiment specifically include the following steps:

[0046] S1. Surface pretreatment: Same as in Example 1;

[0047] S2. Texturing treatment: Same as in Example 1;

[0048] S3. Electrolyte preparation: Add 0.5g of ammonium fluoride granules to a beaker containing 90mL of ethylene glycol, stir magnetically for 40min, then add 10mL of deionized water and continue stirring magnetically for 20min to obtain the electrolyte.

[0049] S4. Magnetic field-assisted anodizing treatment: Electrolyte is injected into an electrolytic cell. Microtextured titanium metal is connected to the positive terminal of a DC power supply as the anode, and a platinum electrode is connected to the negative terminal of a DC power supply as the cathode. A magnetic field of 0.15T perpendicular to the electric field direction is applied, and the microtextured titanium metal is anodized for 2 hours under a voltage of 40V. Titanium nanotubes with a diameter of about 110nm, a wall thickness of about 18nm, and a length of about 13µm are grown in situ on the surface of the microtexture to form a nanotexture. After the oxidation treatment is completed, it is placed in anhydrous ethanol for ultrasonic cleaning for 5 minutes, and then placed in a ventilated place to air dry naturally for 1.5 hours to obtain a titanium coating with a micro-nano composite texture.

[0050] Comparative Example 1

[0051] It is basically the same as Example 1, except that no texturing treatment is performed.

[0052] Comparative Example 2

[0053] The process is basically the same as in Example 1, except that a magnetic field of 0.15T perpendicular to the electric field direction was not applied during the anodizing process.

[0054] Test Example 1

[0055] The surface microstructure of the substrates in Example 1, Comparative Example 1, and Comparative Example 2 was characterized using field emission scanning electron microscopy (FESEM). Simultaneously, energy-dispersive X-ray spectroscopy (EDS) was used to qualitatively and quantitatively analyze the elemental composition, mass percentage, atomic percentage, and elemental distribution of each substrate surface. The results are as follows: Figures 2-4 As shown. From Figures 2-4It can be seen that the microstructure and elemental distribution of the substrates in Example 1 (prepared by nanosecond laser texturing + magnetic field-assisted anodizing), Comparative Example 1 (prepared by untextured + magnetic field-assisted anodizing), and Comparative Example 2 (prepared by nanosecond laser texturing + no magnetic field-assisted anodizing) show significant differences. The substrates in Example 1 and Comparative Example 1, which underwent magnetic field-assisted anodizing, exhibit highly ordered and uniform titanium nanotube arrays with intact walls, regular arrangement, and no obvious defects. However, the substrate in Comparative Example 2, which did not receive magnetic field assistance, shows obvious problems of nanotube array collapse, aggregation, and wall rupture, with significantly reduced structural order and integrity, and the nanotube geometry also exhibits greater dispersion. This is because, in the absence of magnetic field-assisted anodizing, the F in the electrolyte... - The inability to achieve uniform and rapid mass transfer leads to a significant concentration gradient at the titanium / titanium oxide interface, resulting in significant differences in the oxidation and etching reaction kinetics of different micro-regions on the anode surface, with locally high F... - In the high-concentration region, the excessively rapid etching reaction rate leads to over-corrosion of the nanotube walls, ultimately resulting in loss of structural strength and morphological damage. Meanwhile, the introduction of a magnetic field assist induces magnetohydrodynamic convection through Lorentz force, forming "micro-eddies" that significantly thin the static diffusion layer on the electrode surface, accelerating the process. - [TiF6] is uniformly delivered to the reaction front and rapidly removed. 2- This effectively avoids the formation of concentration gradients, ensuring the uniformity and structural integrity of nanotube growth. Furthermore, EDS elemental analysis shows that the surfaces of all three substrates are primarily composed of C, O, and Ti elements, with a uniform overall distribution and no obvious agglomeration. O and Ti are the main elements constituting titanium nanotubes, while C is a trace impurity from the testing process. Moreover, due to the construction of the micro-nano composite texture in Example 1, the ratio of O to Ti elements on its surface more closely matches the stoichiometry of titanium oxides, further confirming that the micro-textured substrate combined with magnetic field-assisted anodizing can optimize the growth process of titanium nanotubes.

[0056] Test Example 2

[0057] Drug-loaded coatings were prepared on the substrates of Comparative Examples 1-2 and Examples 1-2 using electrophoretic deposition (EPD). The specific preparation process was as follows: First, 49.5 mL of deionized water was accurately measured, and 0.5 mL of glacial acetic acid was added. After mixing, 0.5 g of chitosan powder was added, and the mixture was magnetically stirred at room temperature for 2 hours until fully dissolved to obtain a chitosan solution. Next, 0.05 g of curcumin powder was weighed and added to 50 mL of anhydrous ethanol. The mixture was magnetically stirred for 1 hour until completely dissolved to obtain a curcumin solution. Under continuous stirring, the curcumin solution was slowly added dropwise to the chitosan solution. After mixing evenly, the mixture was ultrasonically treated using an ultrasonic cell disruptor. The ultrasonic treatment was set to 15 seconds of continuous operation and 2 seconds of intermittent operation, with a total ultrasonic time of 5 minutes. After ultrasonic treatment, the... The mixed system was allowed to stand for 5 minutes to obtain a stable electrophoretic deposition solution. Subsequently, each substrate was used as the cathode and a platinum sheet as the anode, immersed in the deposition solution, and electrophoretic deposition was performed for 40 minutes under a constant DC voltage of 10V. After deposition, the samples were removed, the unadsorbed particles on the surface were rinsed with anhydrous ethanol, and the samples were allowed to air dry in a ventilated area to obtain the curcumin-loaded coatings corresponding to each substrate. Next, the cross-sectional morphology of the drug-loaded coatings of each sample was characterized using field emission scanning electron microscopy (FESEM), and the coating thickness was determined using image analysis software. The curcumin loading of each coating was quantitatively detected using high-performance liquid chromatography (HPLC), and the elemental distribution of the coating cross-section was analyzed using EDS elemental analysis. The relevant results are as follows: Figures 5-9 As shown. From Figures 5-9It can be seen that the curcumin drug-loaded coatings prepared on different substrate surfaces exhibit significant differences in cross-sectional morphology, coating thickness, and drug loading, and there is a significant positive correlation between coating thickness and drug loading. Comparative Example 1, which did not undergo nanosecond laser texturing, has a substrate surface without micron-level texture, consisting only of nanotube arrays prepared by magnetic field-assisted anodic oxidation. The surface is relatively smooth, limiting the effective contact area and providing fewer coating adhesion sites and nucleation centers during electrophoretic deposition. Therefore, the drug-loaded coating formed by this example has the densest cross-section and the thinnest thickness, corresponding to the highest curcumin drug loading among all samples. The lowest among the three examples; Comparative Example 2, which underwent nanosecond laser texturing but without magnetic field-assisted anodizing, showed defects in the nanotube array on the substrate surface, such as collapse, aggregation, and tube wall rupture. The structural integrity and order of the nanotexture were poor. Although the presence of microtexture increased the specific surface area of ​​the substrate, the defective nanotube array could not fully utilize the carrier role of the nanotexture, resulting in low utilization of coating adhesion sites. Therefore, its coating thickness and drug loading were somewhat improved compared to Comparative Example 1, but the overall effect was still unsatisfactory. In contrast, Examples 1-2, which were prepared by nanosecond laser texturing combined with magnetic field-assisted anodizing, showed that the substrate surface... A well-structured and highly ordered micro / nano composite texture was constructed. The micron-scale texture provided a structured substrate for the nanotube array. The titanium nanotube array prepared with magnetic field assistance had intact walls and a regular arrangement. This micro / nano hierarchical structure greatly increased the specific surface area of ​​the substrate, providing abundant and efficient attachment sites and nucleation centers for curcumin particles and coating matrix during electrophoretic deposition. This allowed the coating to be fully deposited in the recessed areas of the microtexture, within the pores of the nanotubes, and on the surface. Therefore, the thickness of the drug-loaded coating in Examples 1-2 was significantly increased. The cross-section showed that the coating and the substrate formed a tight interlocking structure. The curcumin loading in Example 2 also reached the optimal level. Furthermore, due to the higher voltage and longer time of anodizing, the nanotubes grew more fully, and the specific surface area of ​​the substrate was further increased. The coating thickness and drug loading were slightly improved compared to Example 1. At the same time, the EDS elemental analysis results showed that the characteristic elements of curcumin and coating matrix, such as C and O, were more uniformly distributed in the cross-section of the drug-loaded coatings in Examples 1-2. Moreover, the elemental signals were stronger in the microtexture depressions and nanotube channels, further confirming the promoting effect of micro-nano composite texture on coating deposition and the effect of improving drug loading.

[0058] In summary, the substrate with micro-nano composite texture prepared by this invention significantly increases the specific surface area and the number of surface binding sites by relying on the micro-nano synergistic effect. Compared with single nanotextured substrates and micro-nanotextured substrates with defects, it exhibits superior load-bearing performance in the preparation of drug-loaded coatings, effectively improving the thickness and drug loading of drug-loaded coatings, and solving the technical problem of low drug loading of traditional drug-loaded coatings.

[0059] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a substrate with a micro-nano composite texture, characterized in that, Includes the following steps: S1. Texturization treatment of pretreated metallic titanium is performed using nanosecond laser to form microtextures on the surface of metallic titanium, resulting in microtextured metallic titanium. S2. Add ammonium fluoride to ethylene glycol and stir until homogeneous. Then add water and continue stirring until homogeneous to obtain the electrolyte. S3. Connect the microtextured titanium metal described in S1 to the positive terminal of a DC power supply as the anode and the platinum electrode to the negative terminal of a DC power supply as the cathode. Perform magnetic field-assisted anodic oxidation treatment in the electrolyte described in S2 to form a nanotexture on the surface of the microtextured titanium metal. After ultrasonic cleaning and natural drying, the substrate with the micro-nano composite texture is obtained.

2. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S1, the processing parameters for the texturing process are: laser pulse power of 1W-10W, frequency of 100kHz-500kHz, pulse width of 10ns-15ns, and scanning speed of 20mm / s-200mm / s.

3. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S1, the dimensions of the microtexture are: a depth of 10μm-50μm, a width of 50μm-150μm, and a spacing of 100μm-200μm.

4. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S2, the concentration of ammonium fluoride in the electrolyte is 3 mg / mL-5 mg / mL, and the volume ratio of ethylene glycol to water is (8.8-9.2):

1.

5. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S3, the magnetic field assistance is achieved by applying a magnetic field of 0.12T-0.18T perpendicular to the direction of the electric field through a ring-shaped permanent magnet.

6. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S3, the processing parameters for the anodizing treatment are: voltage of 20V-40V and time of 1h-2h.

7. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S3, the dimensions of the nanotexture are: tube diameter of 90nm-120nm, wall thickness of 15nm-20nm, and length of 8µm-15µm.

8. The method for preparing a substrate with micro-nano composite texture according to claim 1, characterized in that, In S3, the ultrasonic cleaning is performed in anhydrous ethanol for 4-6 minutes. And / or, the natural drying is to air dry in a ventilated place for 1-2 hours.

9. A substrate with a micro-nano composite texture prepared by the method according to any one of claims 1-8.

10. The application of the substrate with micro-nano composite texture as described in claim 9 in drug-loaded coatings.

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