Surface modification method of biomedical titanium plate

Abstract

This invention discloses a surface modification method for biomedical titanium plates, belonging to the field of biomedical materials. The method involves using surface treatment methods such as layer-by-layer self-assembly to deposit hydrophilic nano-titanium dioxide particles modified with polyelectrolytes such as PSS and PAH onto a pretreated pure titanium substrate. By depositing nano-titanium dioxide modified with different polyelectrolytes and nano-titanium dioxide films of varying numbers, the surface hydrophilicity of the titanium plate is effectively improved. This method effectively solves the problem of poor biocompatibility of existing titanium and its alloys as biomedical replacement materials.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials and relates to a surface modification method for biomedical titanium plates. Background Technology

[0002] Rapid economic development has led to rapid social progress, and people's demand for a healthy and fulfilling life has driven a year-on-year increase in the demand for biomedical materials. Titanium and its alloys, with their advantages of strong corrosion resistance, excellent mechanical properties, and high specific strength, and especially their safety and non-toxicity while possessing an elastic modulus similar to human bone, have led to their widespread use in the field of biomedical artificial titanium bones, thus promoting the rapid development of titanium and its alloys as biomedical materials. While artificial titanium alloy bones have reached a relatively mature stage, some issues remain to be addressed. Biocompatibility is one such issue. If biocompatibility problems are not resolved when titanium and its alloys are implanted into the human body as biomedical substitutes, it can lead to poor recovery at the implantation site. Improper handling can cause inflammation, infection, necrosis, and even, in severe cases, sepsis due to infection, resulting in death. Numerous clinical trials have shown that insufficient surface hydrophilicity of titanium leads to decreased biocompatibility. Therefore, improving the hydrophilicity of the titanium surface through surface modification technology is crucial for the rapid healing of the implantation site after artificial titanium bone implantation.

[0003] Currently, many scientists and scholars have explored and researched ways to improve the biocompatibility of artificial titanium bones. Modifying the surface of titanium to enhance its hydrophilicity, thereby improving its biocompatibility as a biomedical material, is a highly feasible research direction and very helpful in addressing the biocompatibility issues of artificial titanium bones. Therefore, finding an effective way to improve the surface hydrophilicity of titanium and its alloys as biomedical grafts is crucial for ensuring the successful use of biomedical titanium and its alloys as transplant materials to repair affected areas and for promoting the integration of the bone-tissue interface after implantation.

[0004] Currently, to improve the biocompatibility of biomedical titanium materials, it is necessary to transform the production process and subsequent processing methods. At present, there are two main approaches to improving the biocompatibility of biomedical titanium: one is to develop novel biomedical titanium materials by adjusting their composition and structure; the other is to modify the surface of biomedical titanium materials. Surface modification of titanium can effectively improve its overall performance as a biomedical material without changing the underlying titanium material. To achieve different changes in the surface properties, various new surface modification technologies can be used, but some modification techniques still have problems due to their immaturity. For example, during plasma spraying, the material in its high-temperature molten state can be oxidized, which will reduce the performance of the prepared product; laser cladding is too complex and requires expensive equipment; chemical vapor deposition has limited applicability, only suitable for preparing small-sized materials. Furthermore, these single surface modification methods cannot simultaneously meet multiple biological needs, leading to difficulties in application. Summary of the Invention

[0005] The technical problem to be solved by this invention is that existing titanium and its alloys have poor biocompatibility as biomedical replacement materials.

[0006] The technical solution adopted by this invention to solve its technical problem is: a surface modification method for biomedical titanium plates, comprising the following steps:

[0007] a. After grinding and cleaning the titanium-based plate, chemically soak it in an acid solution. After soaking, wash it with pure water and blow it dry with nitrogen. Repeat the operation several times and then put it into P-DADMAC solution for shaking and soaking. After soaking, wash it with pure water.

[0008] b. Preparation of TiO2@PAH solution: Nano-titanium dioxide powder and citric acid solution were mixed in a centrifuge tube at a mass ratio of 1:500, ultrasonically vibrated and centrifuged, the supernatant was removed, an equal volume of PAH solution was added to the centrifuge tube, ultrasonically vibrated and centrifuged, the supernatant was removed, deionized water was added to the centrifuge tube again, ultrasonically vibrated and mixed to obtain a TiO2@PAH solution with a concentration of 2 mg / mL;

[0009] c. Preparation of TiO2@PSS solution: Nano-titanium dioxide powder and citric acid solution were mixed in a centrifuge tube at a mass ratio of 1:500, ultrasonically vibrated and centrifuged, the supernatant was removed, an equal volume of PSS solution was added to the centrifuge tube, ultrasonically vibrated and centrifuged, the supernatant was removed, deionized water was added to the centrifuge tube again, ultrasonically vibrated and mixed to obtain a TiO2@PSS solution with a concentration of 2 mg / mL;

[0010] d. The titanium plate treated in step a is immersed in the TiO2@PAH solution obtained in step b and shaken to soak. After soaking, it is washed with deionized water and then immersed in the TiO2@PSS solution obtained in step c and shaken to soak. After soaking, it is washed with deionized water and dried with nitrogen. The operation is repeated multiple times to obtain a biomedical titanium plate with a TiO2@(PAH / PSS) composite structure with surface modification completed through layer-by-layer self-assembly.

[0011] In step a above, the polishing process involves cleaning the titanium-based sheet with hot water and degreasing detergent, polishing it with sandpaper, ultrasonically cleaning it with pure water, and then polishing it with diamond polishing paste.

[0012] Furthermore, polishing was performed using sandpaper of grits 240, 500, 800, 1000, 1500, and 2000 respectively; and polishing was performed using diamond polishing paste of grits 5000, 7000, 10000, 15000, 30000, and 90000 respectively.

[0013] In step a above, the cleaning process involves ultrasonically cleaning the polished titanium-based plate sequentially with acetone, anhydrous ethanol, and deionized water, repeating the process 2-3 times, and then drying it.

[0014] In step a above, the acid solution is a piranha solution, the chemical soaking time is 25-35s, and the operation is repeated 2-3 times; the concentration of P-DADMAC solution is 5-10%, and the shaking soaking time is 25-35min.

[0015] Furthermore, in step a above, before immersing the acid-treated titanium plate in the P-DADMAC solution for ultrasonic oscillation, the acid-treated titanium plate is first immersed in PAH solution for ultrasonic oscillation. After immersion, it is washed with pure water and then immersed in PSS solution. After immersion, it is washed with pure water and dried with nitrogen. This process is repeated multiple times to obtain a titanium plate with a PAH / PSS polyelectrolyte layer. Then, the titanium plate with the PAH / PSS polyelectrolyte layer is immersed in the P-DADMAC solution for ultrasonic oscillation.

[0016] Furthermore, the concentration of PAH solution is 2 mg / mL, the concentration of PSS solution is 2 mg / mL, the soaking time is 25-35 seconds, and the operation is repeated 2-4 times.

[0017] In steps b and c above, the nano-titanium dioxide powder is anatase nano-titanium dioxide powder.

[0018] In step b above, the concentration of citric acid solution is 0.05 mol / L, the concentration of PAH solution is 2 mg / mL, the centrifugation speed is 900 r / min, and the centrifugation time is 4-5 min.

[0019] In step c above, the concentration of citric acid solution is 0.05 mol / L, the concentration of PSS solution is 2 mg / mL, the centrifugation speed is 900 r / min, and the centrifugation time is 4-5 min.

[0020] In step d above, the ultrasonic oscillation soaking time is 25-35 minutes.

[0021] The beneficial effects of this invention are as follows: By using surface treatment methods such as layer-by-layer self-assembly, hydrophilic nano-titanium dioxide particles modified with polyelectrolytes such as PSS and PAH are deposited on a pretreated pure titanium substrate. Through the deposition of nano-titanium dioxide modified with different polyelectrolytes and nano-titanium dioxide films with different numbers of layers, the hydrophilicity of the titanium substrate surface is effectively improved. After surface treatment using the layer-by-layer self-assembly method of this invention, nano-titanium dioxide is uniformly and stably deposited on the surface of the pure titanium substrate, and the wetting angle of the titanium substrate surface changes from approximately 80° to approximately 53°, resulting in a significant improvement in surface hydrophilicity.

[0022] This invention first treats pure titanium plates with acid and P-DADMAC solutions, i.e., through hydroxylation. The reaction between the titanium plate surface and the strongly oxidizing solution removes all organic matter and oxidizes the surface, generating a large number of hydroxyl groups, thus significantly improving the hydrophilicity of the titanium plate surface. Secondly, since nano-titanium dioxide itself has excellent hydrophilicity, the polyelectrolytes of the nano-titanium dioxide modified by this invention have more charge. Combined with the large specific surface area of ​​nano-titanium dioxide, it carries more polyelectrolytes. Furthermore, the charge on the titanium plate after hydroxylation further enhances the hydrophilicity of the self-assembled titanium plate surface, thus improving the biocompatibility of the layer-by-layer self-assembled titanium plate. The surface treatment method of this invention has little impact on the hardness of the titanium plate, and does not affect the internal hardness. This surface treatment method improves the hydrophilicity of the titanium plate surface while ensuring excellent material mechanical properties.

[0023] The surface treatment method of this invention, through chemical immersion and layer-by-layer self-assembly technology, not only boasts advantages such as low cost, simple operation, green and pollution-free nature, and controllable film preparation, but also enables low-cost, large-scale industrial production and is applicable to various complex surface shapes. This invention innovatively coats titanium alloy surfaces with both a polyelectrolyte film and nano-titanium dioxide through layer-by-layer self-assembly, effectively improving the biocompatibility of titanium and its alloys. This composite structure is a fast, safe, efficient, and easily prepared medical material composite film layer that effectively enhances the comprehensive performance and application scenarios of titanium and its alloys as medical materials. It can also be applied in fields beyond biomedical titanium alloy materials, such as self-cleaning and self-wetting materials, providing more possibilities for the development of more novel functional materials. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the process of nano-titanium dioxide after layer-by-layer self-assembly modification of titanium plates according to the present invention;

[0025] Figure 2 This is the EDS energy spectrum of the titanium plate after surface treatment according to the present invention;

[0026] Figure 3 This is a comparison diagram of the contact angles of Embodiment 1 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0027] The technical solution of the present invention can be implemented in the following manner.

[0028] 1. Prepare reagents

[0029] (1) Preparation of piranha solution: Prepare a clean beaker in advance, and then prepare 35 mL of concentrated sulfuric acid. Add the concentrated sulfuric acid to the empty beaker first, and then measure 15 mL of 30% hydrogen peroxide solution. Then slowly add the hydrogen peroxide solution to the concentrated sulfuric acid along the glass rod, and then stir the solution evenly. At this time, a large number of bubbles will be generated.

[0030] (2) Preparation of poly(4-styrene sulfonate) PSS solution: Weigh 0.2g of PAH and 2.922g of NaCl respectively, and prepare 50mL of solution with NaCl concentration of 0.5mol / L and PAH concentration of 2mg / mL.

[0031] (3) Preparation of polyallylamine hydrochloride (PAH) solution: Weigh 0.2 g of PSS and 2.922 g of NaCl respectively, and prepare 50 mL of solution with NaCl concentration of 0.5 mol / L and PSS concentration of 2 mg / mL.

[0032] (4) Preparation of citric acid solution: Prepare a 500mL beaker, add 450mL of deionized water to it, weigh 5.2534g of citric acid monohydrate (C6H8O7·H2O) powder, place the beaker on a magnetic stirrer and stir, then slowly add the citric acid monohydrate to the beaker, wait for the magnetic stirrer to stir until it is completely dissolved, then add deionized water to the beaker to make up to 500mL, and obtain a 0.05mol / L citric acid solution.

[0033] (5) Preparation of TiO2@PAH solution: The prepared citric acid solution was stirred with a magnetic stirrer at a mass ratio of nano-titanium dioxide powder to citric acid solution of 1:500. Then, anatase nano-titanium dioxide powder was slowly added until it was well dispersed in the citric acid solution. The prepared solution was then placed in centrifuge tubes and ultrasonically vibrated to ensure even dispersion. The tubes were then centrifuged at 900 r / min for 4 min. After centrifugation, the centrifuge tubes were removed. At this point, the nano-titanium dioxide... Titanium dioxide has been deposited on the tube wall. After removing the supernatant, add sufficient prepared PAH solution and shake to disperse the nano-titanium dioxide on the tube wall in the solution. Then place the centrifuge tube in an ultrasonic machine for vibration. After vibration, remove the centrifuge tube and centrifuge it at 900 r / min for 4 min. After centrifugation, remove the centrifuge tube, remove the supernatant, add deionized water and shake to disperse the nano-titanium dioxide on the tube wall in the solution. Then place the centrifuge tube in an ultrasonic machine for vibration to prepare TiO2@PAH solution for later use.

[0034] (6) Preparation of TiO2@PSS solution: The prepared citric acid solution was stirred with a magnetic stirrer at a mass ratio of nano-titanium dioxide powder to citric acid solution of 1:500. Then, anatase nano-titanium dioxide powder was slowly added until it was well dispersed in the citric acid solution. The prepared solution was then placed in centrifuge tubes and ultrasonically vibrated to ensure even dispersion. The tubes were then centrifuged at 900 r / min for 4 min. After centrifugation, the centrifuge tubes were removed. At this point, the nano-titanium dioxide... Titanium dioxide has been deposited on the tube wall. After removing the supernatant, add sufficient prepared PSS solution and shake to disperse the nano-titanium dioxide on the tube wall in the solution. Then place the centrifuge tube in an ultrasonic machine for vibration. After vibration, remove the centrifuge tube and centrifuge it at 900 r / min for 4 min. After centrifugation, remove the centrifuge tube, remove the supernatant, add deionized water and shake to disperse the nano-titanium dioxide on the tube wall in the solution. Then place the centrifuge tube in an ultrasonic machine for vibration to prepare TiO2@PSS solution for later use.

[0035] 2. A surface modification method for biomedical titanium plates, comprising the following steps:

[0036] (1) Polishing of titanium plates

[0037] The titanium metal plate is cleaned with hot water and degreasing detergent to remove surface oil stains. Then it is polished with sandpaper of 240, 500, 800, 1000, 1500, and 2000 grits respectively. After ultrasonic cleaning with pure water, it is polished with diamond polishing paste of 5000, 7000, 10000, 15000, 30000, and 90000 grits.

[0038] (2) Cleaning the titanium plate

[0039] The polished pure titanium sheet was ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water, repeating the process three times. After washing, the sample was removed, dried, and sealed with plastic wrap for later use.

[0040] (3) Hydroxylation treatment of titanium plate surface

[0041] The titanium plate was chemically immersed in a piranha solution for 30 seconds each time. After immersion, it was removed, rinsed with pure water, and dried with nitrogen. The process was repeated for the next immersion, and the number of immersions was adjusted as needed. After each immersion, the plate was rinsed with pure water and dried with nitrogen. The plate was then ready for use.

[0042] After being immersed in a strong oxidizing solution, the titanium plate's surface is oxidized and carries a large amount of charge. After being corroded by acid, a thin oxide film is formed on the surface, and a large number of electrons are stripped off, forming numerous ions. Therefore, the surface of the titanium plate also has many electron holes and oxygen holes. When these films come into contact with water, they can react with water and form a hydrophilic structure. At this point, it can be found that the hydrophilicity of the titanium plate surface after hydroxylation treatment is significantly improved compared to before hydroxylation treatment.

[0043] (4) Titanium plate layer-by-layer self-assembled polyelectrolyte

[0044] After hydroxylation treatment, the titanium plate is immersed in the prepared PAH solution and ultrasonically vibrated. Then, the titanium plate is removed and rinsed in pure water to remove excess polyelectrolyte from the surface. The titanium plate is then removed and immersed in the prepared PSS solution. After rinsing in pure water to remove excess polyelectrolyte from the surface, the plate is removed and dried with nitrogen gas for later use. The above steps are repeated to self-assemble multiple PAH / PSS polyelectrolyte layers on the titanium plate.

[0045] (5) Titanium surface coated with poly(diallyldimethylammonium chloride) P-DADMAC

[0046] Take a clean beaker, add a 5-10% P-DADMAC solution, immerse the hydroxylated titanium plate in the P-DADMAC solution, soak for 30 minutes, shake with a shaker during soaking, then remove and gently rinse the titanium surface with deionized water to remove excess P-DADMAC solution.

[0047] (6) Nano-titanium dioxide modified by layer-by-layer self-assembly of titanium plates (e.g.) Figure 1 (As shown)

[0048] The treated titanium plate is immersed in a prepared TiO2@PAH solution and ultrasonically vibrated. After vibration, the titanium plate is removed and rinsed in pure water to remove excess TiO2@PAH from the surface. Then, it is immersed in a prepared TiO2@PSS solution and ultrasonically vibrated. After vibration, the titanium plate is removed and rinsed in pure water to remove excess TiO2@PSS from the surface. After drying with nitrogen, the above steps are repeated to self-assemble a TiO2@(PAH / PSS) composite structure on the surface of the titanium plate, resulting in a biomedical titanium plate with a surface-modified TiO2@(PAH / PSS) composite structure.

[0049] The technical solution and effects of the present invention will be further explained below through practical examples.

[0050] Example

[0051] Multiple experiments were conducted using the surface modification method for biomedical titanium plates of this invention, and corresponding control experiments were set up. The specific steps and experimental results are as follows.

[0052] 1. The surface treatment of the embodiments and comparative examples is shown in Table 1. The pretreatment refers to the process of grinding → cleaning → surface hydroxylation of the titanium-based plate. Layer-by-layer self-assembly refers to the process of surface coating of the titanium plate with P-DADMAC → TiO2@PAH → TiO2@PSS. In Table 1, Comparative Example 1 without pretreatment and layer-by-layer self-assembly is a pure titanium plate without any treatment. The comparative examples are titanium plates that have only undergone pretreatment and have not undergone layer-by-layer self-assembly.

[0053] Table 1. Processes of Examples and Comparative Examples

[0054] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Preprocessing yes yes yes no yes Layer-by-layer self-assembly yes yes yes no no

[0055] 2. Experimental Results

[0056] (1) EDS analysis

[0057] After performing EDS scanning on the self-assembled titanium plates, as shown... Figure 2As shown, after magnifying the titanium plate 20,000 times, a point on the white nano-sized particles on the surface of the titanium plate was selected for energy dispersive spectroscopy (EDS). The analysis revealed that the titanium surface contains three elements: C, O, and Ti, with mass percentages of 12.6%, 32.63%, and 50.57%, respectively. The presence of C indicates that the titanium plate surface has been coated with a polyelectrolyte modified with nano-titanium dioxide. The presence of O and Ti indicates the presence of a compound of titanium and oxygen on the surface. The analysis shows that nano-titanium dioxide has been successfully attached to the titanium plate. Furthermore, the presence of the polyelectrolyte modified with nano-titanium dioxide further demonstrates this, as the significantly improved wettability also supports this conclusion. This also explains why the surface smoothness of the titanium plate decreases after layer-by-layer self-assembly due to the self-assembly of nano-titanium dioxide, thus reducing the gloss of the titanium plate. Since the nano-titanium dioxide particles themselves are white, the whiteness of the titanium plate surface after self-assembly is also improved.

[0058] (2) Surface hydrophilic contact angle analysis

[0059] Research has revealed that the hydrophilicity of titanium's surface directly affects cell adhesion. When biomedical titanium is implanted into the human body, the first substances to come into contact with the implant are proteins. Because proteins also have a certain degree of hydrophilicity, they are rapidly adsorbed onto the biomedical titanium surface. These proteins then guide cells towards the implant and effectively mobilize cellular regeneration, allowing cells that come into contact with them to grow and multiply rapidly. This promotes rapid growth and healing of the tissue at the implantation site. Therefore, surface hydrophilicity directly reflects the biocompatibility of biomedical titanium. Improving the hydrophilicity of biomedical titanium's surface can significantly enhance the subsequent recovery effect after implantation.

[0060] By observing and calculating the titanium plates using a measuring instrument, it was found that the wetting angle of the untreated titanium plate (Comparative Example 1) was about 80°, the wetting angle of the hydroxylated titanium plate (Comparative Example 2) was about 70°, and the wetting angle of the titanium plate after layer-by-layer self-assembly was about 53° (Examples 1-3), as shown in Table 2.

[0061] Table 2. Surface contact angle measurement results of samples from Examples 1-3 and Comparative Examples 1-2.

[0062] sample Unmodified Hydroxylation treatment Layer-by-layer self-assembly Example 1 81.2 72.5 54.8 Example 2 79.3 69.9 52.3 Example 3 76.6 68.7 51.8 Comparative Example 1 79.4 70.2 53.0 Comparative Example 2 80.3 69.9 53.2 mean ± standard deviation 80.0±1.0 70.7±1.0 53.2±1.0

[0063] The calculation formula is as follows: rs represents solid-gas; rsl represents solid-liquid; rx represents liquid-gas.

[0064] The equilibrium equations are: rs = rsl + rx * cosθ; F = rx * cosθ = rs - rsl

[0065] Where θ represents the wetting angle; F represents the wetting tension; and 0°≤θ≤180°, the value of the wetting tension F is greater when θ is approximately 0°. When 0°<θ<90°, the larger the wetting angle, the worse the wetting performance.

[0066] The observation and measurement of the hydrophilicity of the thin film on the titanium surface directly reflects the biocompatibility of the titanium surface. For example... Figure 3 As shown, firstly by Figure 3 (a) As can be seen, measuring the angle between the water droplet and the titanium plate reveals that the wetting angle of the untreated titanium plate is approximately 80°. Further measuring the wetting angle of the hydroxylated titanium plate surface, and comparing it with that of pure titanium, reveals that... Figure 3 As shown in (b), the surface of titanium after hydroxylation is filled with hydroxyl groups. After the titanium plate is stripped of electrons by acid, an ion film is formed on the surface of the titanium plate, which is filled with electron holes and oxygen holes. Once these holes come into contact with water, they will react with water to generate hydroxyl groups. Since hydroxyl groups have a similar structure to water, they are easily attracted by water. Therefore, the hydrophilicity of the titanium plate after hydroxylation is significantly improved, changing from 80° in the untreated plate to about 70°.

[0067] Furthermore, by observing the titanium plates after hydroxylation treatment and those after self-assembly, it is clear that, for example... Figure 3 As shown in (c), the wettability of the titanium surface after layer-by-layer self-assembly significantly increases, changing from approximately 70° after hydroxylation treatment to approximately 53°. This indicates that the anatase nano-titanium dioxide particles self-assembled on the titanium plate surface by this invention increase water adsorption. Because nano-titanium dioxide itself has excellent hydrophilicity, the polyelectrolytes modifying the nano-titanium dioxide also possess a large charge. Furthermore, nano-titanium dioxide has a large specific surface area, thus carrying a large amount of polyelectrolytes, resulting in abundant and numerous charges. Combined with the charges from the hydroxylation treatment, this further enhances the hydrophilicity of the titanium plate surface after self-assembly. This demonstrates that after hydroxylation treatment and subsequent self-assembly of anatase nano-titanium dioxide particles onto the titanium plate, the hydrophilicity of the titanium surface is significantly improved, directly resulting in improved biocompatibility of the titanium surface.

[0068] (3) Hardness analysis of titanium plates

[0069] After conducting Rockwell hardness tests on the titanium plates, as shown in Table 3, the HRC Rockwell hardness of the pure titanium plate was approximately 21.3, the HRC Rockwell hardness of the hydroxylated titanium plate was approximately 21.1, and the HRC Rockwell hardness of the self-assembled titanium plate was approximately 21.2. Because the hydroxylated film and the self-assembled nanofilm on the titanium plate surface are extremely thin, approaching the micrometer level, their impact on the surface hardness of the titanium plate is extremely small, and they have no effect on the internal hardness of the titanium plate. This also indicates that the layer-by-layer self-assembled deposition of titanium dioxide nanofilms on the titanium plate surface has little impact on the hardness of the titanium plate. While improving the hydrophilicity of the titanium plate surface, it basically does not affect the excellent mechanical properties of titanium, which is one of the important factors that makes titanium plates suitable for use as biomedical implants.

[0070] Table 3 Rockwell hardness of samples from Examples 1-3 and Comparative Examples 1-2

[0071] sample Unmodified Hydroxylation treatment Layer-by-layer self-assembly Example 1 21.4 20.8 21.2 Example 2 21.5 20.9 21.5 Example 3 21.1 21.2 21.7 Comparative Example 1 21.5 21.6 20.6 Comparative Example 2 20.7 20.9 21.5 mean ± standard deviation 21.3±0.5 21.1±0.5 21.2±0.5

Claims

1. A method for surface modification of biomedical titanium plates, characterized in that... Includes the following steps: a. After grinding and cleaning, the titanium-based sheet is chemically soaked in an acid solution. After soaking, it is rinsed with pure water and dried with nitrogen. This process is repeated several times. Then, the sheet is immersed in a P-DADMAC solution with shaking. After immersion, it is rinsed with pure water to obtain the treated titanium sheet for later use. The acid solution is piranha solution, the chemical soaking time is 25-35 seconds, and the process is repeated 2-3 times. The P-DADMAC solution concentration is 5-10%, and the shaking soaking time is 25-35 minutes. b. Preparation of TiO2@PAH solution: Nano-titanium dioxide powder and citric acid solution were mixed in a centrifuge tube at a mass ratio of 1:500, ultrasonically vibrated and centrifuged, the supernatant was removed, an equal volume of PAH solution was added to the centrifuge tube, ultrasonically vibrated and centrifuged, the supernatant was removed, deionized water was added to the centrifuge tube again, ultrasonically vibrated and mixed to obtain a TiO2@PAH solution with a concentration of 2 mg / mL; c. Preparation of TiO2@PSS solution: Nano-titanium dioxide powder and citric acid solution were mixed in a centrifuge tube at a mass ratio of 1:500, ultrasonically vibrated and centrifuged, the supernatant was removed, an equal volume of PSS solution was added to the centrifuge tube, ultrasonically vibrated and centrifuged, the supernatant was removed, deionized water was added to the centrifuge tube again, ultrasonically vibrated and mixed to obtain a TiO2@PSS solution with a concentration of 2 mg / mL; d. Immerse the titanium plate treated in step a in the TiO2@PAH solution obtained in step b by shaking and soaking. After soaking, wash it with deionized water. Then immerse it in the TiO2@PSS solution obtained in step c by shaking and soaking. After soaking, wash it with deionized water and dry it with nitrogen. Repeat the operation multiple times to obtain a biomedical titanium plate with a TiO2@(PAH / PSS) composite structure with surface modification as needed by self-assembling layer by layer.

2. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In step a, the polishing process involves cleaning the titanium-based sheet with hot water and degreasing detergent, polishing it with sandpaper, ultrasonically cleaning it with pure water, and then polishing it with diamond polishing paste.

3. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In step a, the cleaning process involves ultrasonically cleaning the polished titanium-based plate sequentially with acetone, anhydrous ethanol, and deionized water, repeating the process 2-3 times, and then drying it.

4. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In step a, before immersing the acid-treated titanium plate in the P-DADMAC solution with shaking, the acid-treated titanium plate is first immersed in PAH solution with shaking. After immersion, it is washed with pure water and then immersed in PSS solution. After immersion, it is washed with pure water and dried with nitrogen. This process is repeated several times to obtain a titanium plate with a PAH / PSS polyelectrolyte layer. Then, the titanium plate with the PAH / PSS polyelectrolyte layer is immersed in the P-DADMAC solution with shaking.

5. The surface modification method for biomedical titanium plates according to claim 4, characterized in that: The concentration of PAH solution is 2 mg / mL, the concentration of PSS solution is 2 mg / mL, the soaking time is 25-35s, and the operation is repeated 2-4 times.

6. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In steps b and c, the nano-titanium dioxide powder is anatase nano-titanium dioxide powder.

7. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In step b, the concentration of citric acid solution is 0.05 mol / L, the concentration of PAH solution is 2 mg / mL, the centrifugation speed is 900 r / min, and the centrifugation time is 4-5 min.

8. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In step c, the concentration of citric acid solution is 0.05 mol / L, the concentration of PSS solution is 2 mg / mL, the centrifugation speed is 900 r / min, and the centrifugation time is 4-5 min.

9. The surface modification method for biomedical titanium plates according to claim 1, characterized in that: In step d, the shaking soaking time is 25-35 minutes.

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