A method for preparing a gradient size nanowire coating on a medical titanium surface

Abstract

The present application belongs to the technical field of surface modification of biomedical materials, and specifically relates to a method for preparing a gradient-size nanowire coating on a medical titanium surface, comprising the following steps: first, titanium sheets are subjected to acid pickling pretreatment to remove the surface oxide layer, then sodium hydroxide solution is uniformly and slowly added dropwise, and a continuous-size nanowire coating is obtained through a gradient alkali etching method, laying a foundation for accurate screening of the size of the nanowire coating based on the functions of bone integration-related cells. In addition, compared with traditional orthogonal experiment screening materials, this gradient screening can realize accurate screening of the material structure, improve the screening efficiency, and the required equipment is simple, low in cost, and high in operability, and has high practicability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface modification of biomedical materials, and particularly relates to a method for preparing a gradient-size nanowire coating on a medical titanium surface. BACKGROUND

[0002] In recent years, more than 1 million bone endoprosthesis replacement surgeries are performed worldwide each year for the functional improvement of patients with osteoarthritis and other bone tissue damage, and as the population ages, the demand for bone endoprosthesis replacement will remain high. Implant loosening after implantation leads to more than half of the implantation surgery failures, and the reason for this phenomenon is the insufficient bone integration between the implant and the bone tissue interface. Titanium has the advantages of light weight, high strength, good biocompatibility, strong corrosion resistance, and similar density to human bone. In the 1950s, the United States and the United Kingdom began to implant pure titanium as an endoprosthesis, and since then, pure titanium has been widely used as artificial joints, artificial bones, orthotics, and surgical instruments in clinical applications, and has greatly improved the quality of life of patients with end-stage osteoarthritis and other diseases. However, pure titanium as a biologically inert metal has poor surface activity, is not easy to combine with natural bone after implantation, and can easily cause inflammation, ultimately leading to implant failure and other problems, causing great harm to the physical and mental health of patients.

[0003] Titanium implants can change their surface properties after certain surface treatment, promote cell adhesion and protein adsorption, and promote bone integration. Since the 1990s, pure titanium has been immersed in sodium hydroxide (NaOH) aqueous solution for alkaline etching treatment, which can grow a sodium titanate nanowire coating perpendicular to the surface on the surface of pure titanium. This nanowire coating can change the biological activity of the pure titanium surface, regulate the function of bone integration-related cells, and ultimately determine the bone integration ability of the implant in the body. Studies have shown that the size of the nanowire has a greater impact on the function of bone integration-related cells, but it is still not conclusive which size of nanowire can best promote the function of bone integration-related cells.

[0004] The traditional method for preparing nanowire coating on the surface of titanium by alkali etching treatment is to immerse the titanium sheet completely in NaOH aqueous solution, and take out after a fixed time to prepare a single size nanowire coating on the surface of titanium. By changing the immersion time of titanium sheet in NaOH solution and other parameters, nanowire coatings of different sizes can be prepared to screen the coating nanowire size with better bone integration ability through orthogonal test. However, the nanowire coating prepared by this treatment method cannot systematically study the continuous change of the function of bone integration related cells with the size of nanowire, that is, the size of nanowire cannot be accurately screened through the function of bone integration related cells. Therefore, it is of great significance for constructing titanium implant coating with high bone integration ability to prepare gradient nanowire coating with continuously changing size on the surface of pure titanium, culture bone integration related cells on the surface thereof, and then accurately screen the size of nanowire based on the function of related cells to determine the nanowire size most conducive to bone integration. SUMMARY

[0005] The purpose of the present application is to provide a method for preparing gradient size nanowire coating on the surface of medical titanium. First, the titanium sheet is pretreated by acid pickling to remove the surface oxide layer, and then sodium hydroxide solution is added uniformly and slowly to prepare a nanowire coating with continuously changing size by gradient alkali etching method, which lays a foundation for accurate screening of the size of nanowire coating based on the function of bone integration related cells.

[0006] The present application is implemented by using the following technical solutions:

[0007] A method for preparing gradient size nanowire coating on the surface of medical titanium, comprising the following steps:

[0008] (1) Titanium sheet pretreatment: the titanium sheet is placed in an aqueous solution containing hydrofluoric acid and nitric acid for pretreatment to remove the surface oxide layer;

[0009] (2) The pretreated titanium sheet is vertically placed in a container, and NaOH solution is added into the container containing the titanium sheet to prepare a gradient nanowire coating on the surface of titanium.

[0010] Further preferably, before the titanium sheet is pretreated, the titanium sheet is sequentially immersed in acetone, alcohol and ultrapure water for ultrasonic cleaning for 10 minutes respectively, and is dried for standby use.

[0011] Further preferably, in step (1), the volume ratio of HF, HNO3 and water is 1:1:2. The concentration of HF is 40%; the concentration of HNO3 is 68%.

[0012] Further preferably, in step (2), the concentration of NaOH solution is 2.5M-15M. The dropping rate of NaOH solution is 0.5ml / h-1ml / h. The dropping time of NaOH solution is 48h-96h.

[0013] The method for preparing the gradient size nanowire coating on the medical titanium surface in the application, the nanowire diameter of the prepared coating can continuously vary between 10 nm to 57 nm, and the preparation of the coating with the continuous size nanowire is successfully realized, which lays a foundation for the accurate screening of the nanowire size of the coating based on the cell function related to bone integration. During the reaction process, F- in the acid solution will invade the surface oxide layer of Ti, and then further destroy the Ti matrix. The continuous dropping of the NaOH solution makes the upper part of Ti gradually corroded, and OH - continuously attacks Ti and the residual TiO2 on the surface, and in this process, local anode and cathode reactions occur: on the cathode, Ti(OH) 3+ reacts with OH - to generate H2 by hydration and is adsorbed on the near-surface of the sample. On the anode, the negatively charged and hydrated substrate can combine with Na + to form a porous sodium titanate layer, and with the passage of time, these processes gradually intensify, and the Ti matrix with a longer corrosion time at the bottom forms a nanowire structure with a larger size and depth.

[0014] The application has a reasonable design, and the preparation of the coating with the continuous size nanowire is realized, which lays a foundation for the accurate screening of the nanowire size of the coating based on the cell function related to bone integration. Moreover, compared with the traditional orthogonal experiment screening material, the gradient screening can not only realize the accurate screening of the material structure, but also greatly improve the screening efficiency, and the required equipment is simple, the cost is low, the operability is strong, has high practicability, and has good practical application value. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the application and, together with the specification, serve to explain the principles of the application.

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without any creative effort on the premise of not paying any creative effort.

[0017] Figure 1 An optical photo of the gradient size nanowire coating prepared on the titanium surface in Example 1 of the application is shown.

[0018] Figure 2 A scanning electron microscope photo of the gradient size nanowire coating prepared on the titanium surface in Example 1 of the application is shown.

[0019] Figure 3This image shows a live / dead staining photograph of macrophages cultured on a gradient-sized nanowire coating on a titanium surface, as described in Example 1 of this invention.

[0020] Figure 4 This image shows a scanning electron microscope (SEM) image of macrophages cultured on a gradient-size nanowire coating on a titanium surface in Example 1 of this invention.

[0021] Figure 5 An optical photograph showing the gradient-size nanowire coating prepared on the titanium surface in Example 2 of the present invention.

[0022] Figure 6 This is a scanning electron microscope image showing the gradient-size nanowire coating prepared on the titanium surface in Example 2 of the present invention.

[0023] Figure 7 An optical photograph showing the gradient-size nanowire coating prepared on the titanium surface in Example 3 of the present invention.

[0024] Figure 8 This is a scanning electron microscope image showing the gradient-size nanowire coating prepared on the titanium surface in Example 3 of the present invention.

[0025] Figure 9 An optical photograph showing the gradient-size nanowire coating prepared on the titanium surface in Example 4 of the present invention.

[0026] Figure 10 This is a scanning electron microscope image showing the gradient-size nanowire coating prepared on the titanium surface in Example 4 of the present invention.

[0027] Figure 11 This image shows a live / dead staining photograph of macrophages cultured on a gradient-sized nanowire coating on a titanium surface, as shown in Example 4 of this invention.

[0028] Figure 12 This image shows a scanning electron microscope (SEM) image of macrophages cultured on a gradient-sized nanowire coating on a titanium surface in Example 4 of this invention.

[0029] Figure 13 An optical photograph showing the gradient-size nanowire coating prepared on the titanium surface in Example 5 of the present invention.

[0030] Figure 14 This is a scanning electron microscope image showing the gradient-size nanowire coating prepared on the titanium surface in Example 5 of the present invention.

[0031] Figure 15 This image shows a live / dead staining photograph of macrophages cultured on a gradient-sized nanowire coating on a titanium surface in Example 5 of this invention.

[0032] Figure 16A scanning electron microscope photo showing macrophages cultured on the gradient size nanowire coating on the titanium surface in Example 5 of the present application. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the schemes of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0034] In the description, it should be noted that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. It should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0035] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein; obviously, the examples in the description are only some of the embodiments of the present application, not all the embodiments.

[0036] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Example 1

[0037] A method for preparing a gradient size nanowire coating on a medical titanium surface: a titanium sheet with a length and width of 32 mm and 10 mm is tested, the titanium sheet is vertically placed in a beaker, and NaOH solution is slowly and uniformly injected into the beaker through an automatic liquid adding device, and a gradient size nanowire coating is prepared on the surface of the titanium sheet.

[0038] The specific operation steps are as follows:

[0039] (1) Titanium sheet surface pretreatment:

[0040] A titanium sheet with a length and width of 32 mm and 10 mm is sequentially immersed in acetone, alcohol and ultrapure water for ultrasonic cleaning for 10 minutes, and then immersed in a mixed solution of HF (concentration of 40%), HNO3 (concentration of 68%) and H2O with a volume ratio of 1:1:2 for 10 seconds to remove the oxide film on the surface of the titanium sheet, thereby obtaining a pretreated titanium sheet.

[0041] (2) Alkaline etching treatment of the surface of the titanium sheet:

[0042] The pretreated titanium sheet is ultrasonically cleaned, dried and vertically placed in a beaker with a volume of 100 ml. An automatic liquid feeding device is used to inject 2.5 M NaOH solution into the beaker at a speed of 0.5 ml / h at room temperature. The injection time is 96 h, and the titanium sheet is gradually immersed in the NaOH solution from bottom to top for a gradually decreasing time, so as to prepare a nano-wire coating with gradient size on the surface of the titanium sheet.

[0043] Figure 1 The optical photo of the gradient nano-wire coating prepared on the surface of the titanium sheet by the above method in Example 1 of the present application is shown. It can be seen that the color of the surface coating of the sample gradually changes, indicating that the size of the coating gradually changes. Ten positions on the sample that have experienced different alkali etching times are selected, and the surface morphology of the coating at different positions is observed by a scanning electron microscope. The observation results are shown in FIG. 2. Figure 1 Figure 2 It can be seen that the titanium sheet treated by NaOH alkali etching has a nano-wire structure, and the diameter of the nano-wire gradually increases with the extension of the alkali etching time, from 10 nm after alkali etching for 0.5 h to about 40 nm after alkali etching for 96 h. The above results show that a nano-wire coating with gradient size is successfully prepared on the surface of the titanium sheet by the present Example 1. Figure 3 The live and dead staining photo of the macrophages cultured on the surface of the gradient sample shows that no obvious dead cells (red) appear on the surface of the sample, indicating that the gradient nano-wire coating has no cytotoxicity, and the macrophages can grow normally on the surface of the sample. Figure 4 The scanning electron microscope photo of the macrophages on the gradient nano-wire layer shows that the cells can well adhere to and spread on the surface of the coating, but the adhesion effect of the small-size nano-wire coating is better than that of the large-size coating, indicating that the size of the nano-wire has a significant influence on the adhesion of the macrophages. Example 2

[0044] A method for preparing a gradient nano-wire coating on the surface of a medical titanium sheet: a titanium sheet with a length and a width of 32 mm and 10 mm, respectively, is used for the test. The titanium sheet is vertically placed in a beaker, and a NaOH solution is slowly and uniformly injected into the beaker by an automatic liquid feeding device, so as to prepare a gradient nano-wire coating on the surface of the titanium sheet.

[0045] The specific operation steps are as follows:

[0046] (1) Surface pretreatment of the titanium sheet:

[0047] The titanium sheet with a length and a width of 32 mm and 10 mm, respectively, is sequentially immersed in acetone, alcohol and ultrapure water for ultrasonic cleaning for 10 minutes. Then, the titanium sheet is immersed in a mixed solution of HF (concentration of 40%), HNO3 (concentration of 68%) and H2O with a volume ratio of 1:1:2 for 10 seconds, so as to remove the oxide film on the surface of the titanium sheet, and a pretreated titanium sheet is obtained. ​

[0048] (2) Alkaline etching treatment on the surface of titanium sheet:

[0049] After ultrasonic cleaning of the pretreated titanium sheet, the titanium sheet was dried and vertically placed in a beaker with a volume of 100 ml. An automatic liquid feeding device was used to inject 5M NaOH solution into the beaker at a speed of 0.5 ml / h at room temperature. The injection time was 96 h, and the titanium sheet was gradually immersed in the NaOH solution from bottom to top for a gradually decreasing time, so as to prepare a gradient size nanowire coating on the surface of the titanium sheet.

[0050] Figure 5 The optical photo of the gradient size nanowire coating prepared on the surface of the titanium sheet by the above method in Example 2 of the present application is shown. It can be seen that the color of the coating on the surface of the sample gradually changes, indicating that the size of the coating gradually changes. Ten positions on the sample that have undergone different alkaline etching times are selected, and the surface morphology of the coating at different positions is observed by scanning electron microscopy, and the observation results are shown in FIG. 2. Figure 5 The optical photo of the gradient size nanowire coating prepared on the surface of the titanium sheet by the above method in Example 2 of the present application is shown. It can be seen that the color of the coating on the surface of the sample gradually changes, indicating that the size of the coating gradually changes. Ten positions on the sample that have undergone different alkaline etching times are selected, and the surface morphology of the coating at different positions is observed by scanning electron microscopy, and the observation results are shown in FIG. 2. Figure 6 It can be seen that the titanium sheet treated by NaOH alkaline etching has a nanowire structure, and the diameter of the nanowire gradually increases from 10 nm after alkaline etching for 0.5 h to about 49 nm after alkaline etching for 96 h. The above results show that a gradient size nanowire coating is successfully prepared on the surface of the titanium sheet by the present example. Example 3

[0051] A method for preparing a gradient size nanowire coating on the surface of a medical titanium sheet: a titanium sheet with a length and width of 32 mm and 10 mm, respectively, is tested, the titanium sheet is vertically placed in a beaker, and NaOH solution is slowly and uniformly injected into the beaker by an automatic liquid feeding device, so as to prepare a gradient size nanowire coating on the surface of the titanium sheet.

[0052] The specific operation steps are as follows:

[0053] (1) Pretreatment of the surface of the titanium sheet:

[0054] A titanium sheet with a length and width of 32 mm and 10 mm, respectively, is sequentially immersed in acetone, alcohol and ultrapure water for ultrasonic cleaning for 10 minutes, and then immersed in a mixed solution of HF (concentration of 40%), HNO3 (concentration of 68%) and H2O with a volume ratio of 1:1:2 for 10 seconds, so as to remove the oxide film on the surface of the titanium sheet, and obtain a pretreated titanium sheet.

[0055] (2) Alkaline etching treatment on the surface of the titanium sheet:

[0056] The pretreated titanium sheet is ultrasonically cleaned, dried and vertically placed in a beaker with a volume of 100 ml. An automatic liquid feeding device is used to inject 10 M NaOH solution into the beaker at a speed of 0.5 ml / h at room temperature. The injection time is 96 h. The titanium sheet is gradually immersed in the NaOH solution from bottom to top for a gradually decreasing time, so as to prepare a nano-wire coating with gradient size on the surface of the titanium sheet.

[0057] Figure 7 An optical photo of the nano-wire coating with gradient size prepared on the surface of the titanium sheet by the above method in Example 3 of the present application is shown. It can be seen that the color of the surface coating of the sample gradually changes, indicating that the size of the coating gradually changes. Ten positions on the sample that have experienced different alkali etching times are selected. Figure 7 The surface morphology of the coating at different positions is observed by a scanning electron microscope. The observation results are shown in FIG. 2. Figure 8 It can be seen that the titanium sheet treated by NaOH alkali etching has a nano-wire structure, and the diameter of the nano-wire gradually increases with the extension of the alkali etching time, from 10 nm for 0.5 h alkali etching to about 52 nm for 96 h alkali etching. The above results show that a nano-wire coating with gradient size is successfully prepared on the surface of the titanium sheet by the present example. Example 4

[0058] A method for preparing a nano-wire coating with gradient size on the surface of a medical titanium sheet: a titanium sheet with a length and width of 32 mm and 10 mm, respectively, is used for the test. The titanium sheet is vertically placed in a beaker. An automatic liquid feeding device is used to slowly and uniformly inject NaOH solution into the beaker, so as to prepare a nano-wire coating with gradient size on the surface of the titanium sheet.

[0059] The specific operation steps are as follows:

[0060] (1) Pretreatment of the surface of the titanium sheet:

[0061] The titanium sheet with a length and width of 32 mm and 10 mm, respectively, is ultrasonically cleaned in acetone, alcohol and ultrapure water for 10 minutes, respectively. Then, the titanium sheet is immersed in a mixed solution of HF (concentration of 40%), HNO3 (concentration of 68%) and H2O with a volume ratio of 1:1:2 for 10 seconds, so as to remove the oxide film on the surface of the titanium sheet, thereby obtaining a pretreated titanium sheet.

[0062] (2) Alkali etching treatment of the surface of the titanium sheet:

[0063] The pretreated titanium sheet is ultrasonically cleaned, dried and vertically placed in a beaker with a volume of 100 ml. An automatic liquid feeding device is used to inject 10 M NaOH solution into the beaker at a speed of 0.5 ml / h at room temperature. The injection time is 96 h. The titanium sheet is gradually immersed in the NaOH solution from bottom to top for a gradually decreasing time, so as to prepare a nano-wire coating with gradient size on the surface of the titanium sheet.

[0064] Figure 9 An optical photo of the gradient size nanowire coating prepared on the surface of the titanium sheet by the above method in Example 4 of the present application is shown. It can be seen that the color of the surface coating of the sample gradually changes, indicating that the size of the coating gradually changes. Ten positions on the sample that have undergone different alkali etching times are selected, and the surface morphology of the coating at different positions is observed by scanning electron microscopy, and the observation results are shown in FIG. 6. Figure 9 Figure 10 It can be seen that the titanium sheet surface treated by NaOH alkali etching has a nanowire structure, and the diameter of the nanowire gradually increases with the extension of the alkali etching time, from 10 nm of alkali etching for 0.5 h to about 57 nm of alkali etching for 96 h. The above results show that a gradient size nanowire coating is successfully prepared on the surface of the titanium sheet by the present Example 4. Figure 11 The live and dead staining photos of the macrophages cultured on the surface of the gradient sample show that there are no obvious dead cells (red) on the surface of the sample, indicating that the gradient size nanowire coating has no cytotoxicity, and the macrophages can grow normally on the surface of the sample. Figure 12 The scanning electron microscope photos of the macrophages on the gradient nanowire layer show that the cells can adhere and spread well on the surface of the coating, but the adhesion effect of the small size nanowire coating is better than that of the large size coating, indicating that the size of the nanowire has a significant influence on the adhesion of the macrophages. Example 5

[0065] A method for preparing a gradient size nanowire coating on a medical titanium surface: a titanium sheet with a length and a width of 32 mm and 10 mm, respectively, is tested, the titanium sheet is vertically placed in a beaker, and NaOH solution is slowly and uniformly injected into the beaker through an automatic liquid adding device to prepare a gradient size nanowire coating on the surface of the titanium sheet.

[0066] The specific operation steps are as follows:

[0067] (1) Titanium sheet surface pretreatment:

[0068] A titanium sheet with a length and a width of 32 mm and 10 mm, respectively, is sequentially immersed in acetone, alcohol and ultrapure water for ultrasonic cleaning for 10 minutes, and then it is placed in a mixed solution of HF (concentration of 40%), HNO3 (concentration of 68%) and H2O with a volume ratio of 1:1:2 for immersion for 10 seconds to remove the oxide film on the surface of the titanium sheet, thereby obtaining a pretreated titanium sheet.

[0069] (2) Titanium sheet surface alkali etching treatment:

[0070] ​The pretreated titanium sheet is cleaned by ultrasonic and dried, and then vertically placed in a beaker with a volume of 100 ml. An automatic liquid feeding device is used to inject 2.5M NaOH solution into the beaker at a speed of 1 ml / h at room temperature, and the injection time is 48 h. The titanium sheet is immersed in the NaOH solution from bottom to top, and the immersion time gradually decreases, so as to prepare a nano-wire coating with gradient size on the surface of the titanium sheet.

[0071] Figure 13 The optical photo of the gradient nano-wire coating prepared on the surface of the titanium sheet by the above method in Example 5 of the present application is shown. It can be seen that the color of the surface coating of the sample gradually changes, indicating that the size of the coating gradually changes. Ten positions on the sample that have experienced different alkali etching times are selected, and the surface morphology of the coating at different positions is observed by a scanning electron microscope, and the observation results are shown in FIG. 2. Figure 13 Figure 14 It can be seen that the titanium sheet surface treated by NaOH alkali etching has a nano-wire structure, and the diameter of the nano-wire gradually increases with the extension of the alkali etching time, from 10 nm of alkali etching for 0.5 h to about 31 nm of alkali etching for 48 h. The above results show that the gradient nano-wire coating is successfully prepared on the surface of the titanium sheet by the present Example 5. Figure 15 The live and dead staining photo of the macrophages cultured on the surface of the gradient sample shows that there is no obvious dead cell (red) on the surface of the sample, indicating that the gradient nano-wire coating has no cytotoxicity, and the macrophages can grow normally on the surface of the sample. Figure 16 The scanning electron microscope photo of the macrophages on the gradient nano-wire coating shows that the cells can well adhere and spread on the surface of the coating, but the adhesion effect of the small-size nano-wire coating is better than that of the large-size coating, indicating that the size of the nano-wire has a significant influence on the adhesion of the macrophages.

[0072] In specific implementation, the automatic liquid feeding device is an existing product, which can be purchased from Shanghai Land Medical Instrument Co., Ltd., and the model is LD-P2020 II.

[0073] ​In summary, the five groups of examples can all prepare the nano-wire structure with gradient size. In example 1, the nano-wire size increases at a slow speed, and the macrophages cultured on the surface can well adhere and spread. When the concentration of NaOH solution increases to 5M, the nano-wire size mutates from 0.5h to 6h; when the concentration of NaOH solution continues to increase to 10M and 15M, the nano-wire structure with larger size has collapsed, and the macrophages cultured on the surface of the coating are spherical and cannot normally adhere to the surface of the sample. Compared with example 1, the nano-wire coating prepared in example 5 with shorter etching time has smaller size change, and the cell adhesion effect has no obvious change. In summary, the nano-wire coating prepared under the condition of example 1 has obvious size change, no structure collapse phenomenon occurs, and is suitable for cell adhesion and spreading, and is expected to be used as a sample for subsequent experiments to continue to evaluate the cell function.

[0074] The above merely describes the specific embodiments of the present application, so that those skilled in the art can understand or implement the present application. Although the foregoing embodiments are described in detail, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered in the protection scope of the claims.

Claims

1. A method of producing a gradient size nanowire coating on a medical titanium surface, characterized by: It comprises the following steps: (1) titanium sheet pretreatment: the titanium sheet is placed in a water solution containing hydrofluoric acid and nitric acid for pretreatment to remove the surface oxide layer; wherein the volume ratio of HF, HNO3 and water is 1:1:2, the concentration of HF is 40%, and the concentration of HNO3 is 68%; (2) the pretreated titanium sheet is vertically placed in a container, and NaOH solution is dropped into the container containing the titanium sheet to prepare a titanium surface gradient nanowire coating; wherein the concentration of the NaOH solution is 2.5M-15M, the dropping speed of the NaOH solution is 0.5mL / h-1mL / h, and the dropping time of the NaOH solution is 48h-96h.

2. The method of claim 1, wherein the method is characterized by: Before the titanium sheet is pretreated, the titanium sheet is sequentially immersed in acetone, alcohol and ultrapure water for ultrasonic cleaning for 10 minutes, and is dried for standby use.

3. The method of claim 2, wherein the method is characterized by: In step (2), the concentration of the NaOH solution is 2.5M, the dropping speed of the NaOH solution is 0.5mL / h, and the dropping time is 96h.

Images