CN103290455A - A highly bioactive titanium dioxide film with micro/nano dual structure and preparation method thereof - Google Patents

Abstract

A titanium dioxide film with high biological activity and micro/nano dual structure and a preparation method thereof belong to the field of biomedical materials and surface engineering. The preparation method of the film comprises the following steps: the method comprises the following steps of carrying out micro-arc oxidation on the surface of the cleaned titanium metal, wherein an electrolyte is a lithium tetraborate aqueous solution, a power supply is a bipolar pulse micro-arc oxidation power supply, the working voltage of the power supply is 360-500V, and the current density of the power supply is 1-4A/dm²The pulse frequency is 400-700 Hz, the duty ratio is 10% -30%, and the oxidation time is 1-30 minutes. The morphology of the obtained film is as follows: the uniformly dispersed micron-scale grooves and the nano-scale holes are overlapped and distributed on the surface of the whole film layer. The titanium dioxide film with micro/nano dual structure determines the special performance: the film layer has super strong wetting ability, and the contact angles of water and oil are zero. The method has important significance for the new generation dental implant which can bear large occlusal force and has short healing period. The preparation process is simple, the electrolyte is pollution-free, and the large-scale production and industrial popularization are easy.

Description

A highly bioactive titanium dioxide film with micro/nano dual structure and preparation method thereof

technical field

The invention relates to a highly biologically active titanium dioxide film with a micro/nano dual structure and a preparation method thereof. The titanium dioxide thin film can be used as a surface modification layer of a human body hard tissue substitute material, and belongs to the fields of biomedical materials and surface engineering.

technical background

Compared with other metal medical implant materials, titanium metal has become a popular choice for dental implants, bone trauma products and artificial joints because of its low elastic modulus, low density, high specific strength, excellent corrosion resistance, and good processing and forming properties. It is the preferred material for human hard tissue substitutes and restorations, and it has been more and more widely used clinically. After hard tissue replacement materials are implanted into the human body, they must be well fixed with the surrounding bone tissue. Typically, in the field of denture implantation, the dental implant completely needs to form osseointegration with the alveolar bone for fixation. The prerequisite for the rapid formation of osseointegration between the implant and the bone is to establish direct contact between the bone and the implant without the intervention of connective tissue or other non-osseous tissues, which strongly depends on the surface of the implant. characteristic. The reason why the corrosion resistance of titanium metal is excellent is that a complete and dense TiO ₂ protective layer will be formed on its surface naturally. This layer of protective layer has good biological inert properties, they will not chemically bond with bone, and cannot induce bone growth like Ca and P containing coatings. Studies in the literature [Liu XY, Chu PK, Ding CX. Surface modification of titanium, titanium alloys, and related materials for biomedical applications. Materials Science and Engineering, 2004; R47:49–121] have shown that this plant with a biologically inert surface After the implant is implanted into the human body, it will be quickly wrapped by a layer of fibrous tissue to isolate it from the surrounding bone tissue, thus preventing or weakening the direct connection between the surface of the implant and the bone tissue. Therefore, how to improve the biological activity of the titanium dioxide film on the surface of titanium metal implants, improve the compatibility of its hard tissue or bone tissue, and promote the formation of osseointegration is the core issue of whether modern biomedical titanium can be widely used clinically. One of the difficulties that need to be solved urgently.

Literature [Geetha M, Singh AK, Asokamani R, et al.Ti based biomaterials, the ultimate choice for orthopedic implants–A review. Progress in Materials Science, 2009;54:397-425], [Tian Y, Ding SY, Peng H ,ea al.Osteoblast growth behavior on porous-structure titanium surface.Applied Surface Science,2012;261:25-30] and literature [Rupp F,Scheideler L,Olshanska N,et al.Enhancing surface free energy and hydraulicity through chemical modification of microstructured titanium implant surfaces.Journal of Biomedical Materials Research Part A,2006;76A(2):323-334], [Stadlinger B,Lode AT,Eckelt U,et al.Surface-conditioned dental implants:an animal study on bone formation.Journal of ClinicalPeriodontology,2009;36:882-891] pointed out that improving the surface roughness of titanium metal and enhancing its surface hydrophilicity can strengthen the interaction between it and the biological environment, and promote the adsorption, differentiation and final bone formation of osteoblasts. The formation of the bond enhances the biological activity of titanium metal. The literature [Huang Weixin. Preparation of superhydrophilic porous TiO2 film and research on superhydrophilic mechanism. Guangzhou: South China University of Technology, 2010] pointed out that there is a correlation between the roughness of the material surface and its surface hydrophilicity. The improvement of the surface roughness of the material has a greater promotion effect on its surface hydrophilicity. But in fact, the roughness can not reflect the regular characteristics of the microscopic topography of the material surface, the literature [Koch K,Barthlott W.Superhydrophobic and superhydrophilic plant surfaces: an inspiration for biomimeticmaterials.Philosophical Transactions of the Royal Society A,2009;367:1487- 1509] showed that only the micro/nano dual or multiple regular structures with bionic features on the surface could exhibit excellent hydrophilicity and biological properties. Therefore, inventing and preparing a _TiO2 modified layer on the surface of titanium metal with micro/nano dual or multiple microstructural features on the surface, which has higher roughness and exhibits superhydrophilic properties, is the key to improving its biological activity. Best way.

The traditional micro-arc oxidation method can prepare TiO ₂ porous structure on the surface of titanium metal. The porous structure is mostly single crater-like, does not have micro/nano dual structure characteristics, and has poor hydrophilicity, which leads to its biological activity and osseointegration. Capability is also lower. Selecting a specific electrolyte for micro-arc oxidation can prepare a TiO ₂ film layer with wrinkled pores and grooves on the surface of titanium metal, which can improve the surface roughness of titanium metal and make it exhibit super-hydrophilic properties. Such as the technical solution previously invented by the inventor (Chinese invention patent: a preparation process patent application number of super-wettable wrinkled pore-shaped titanium dioxide film: 201210096780.5). The technical solution is to obtain a titanium dioxide film in situ on the surface of pure titanium by using plasma micro-arc oxidation technology. The electrolyte used is prepared by adding 0.07-1.2 mol of sodium tetraborate into 1000 g of deionized water. The characteristics of the film prepared by using this electrolyte are as follows: the surface is composed of wrinkled pores and nano-scale micropores evenly distributed around the pores; the surface is composed of uniformly distributed porous structures below the surface or inside the membrane layer; the surface is wrinkled. The inner porous structure is occasionally connected. In this preparation process, the pore size, depth and density of the titanium dioxide film are controlled by changing the time of micro-arc oxidation to ensure that the obtained titanium dioxide film has no internal stress and has good wettability; To obtain an oxide film with suitable hole density and depth. Due to the limitation of the selected electrolyte, the TiO ₂ modified film prepared by this technical solution still has insufficient biological activity performance. The main problems are as follows: ① When sodium tetraborate is used as the electrolyte, although the prepared TiO ₂ The membrane layer structure is composed of micron-scale wrinkled pores and nanoscale micropores evenly distributed around the pores, but the interconnection of the micron-scale pores is not enough, and the number of nanoscale pores is small and the depth is shallow, making the film layer The structure is dominated by micron-scale pore structure, the micro/nano dual structure features are not obvious, and the superhydrophilic performance of the film layer cannot be fully utilized; adsorption and growth.

Contents of the invention

The purpose of the present invention is to provide a highly biologically active titanium dioxide film with a micro/nano dual structure and a preparation method thereof to address the problems and deficiencies in the above-mentioned prior art. The titanium dioxide micro-arc oxidation film layer has remarkable micro/nano dual structure characteristics, and should have more excellent superhydrophilic performance and biological activity compared with the prior art. As the surface modification layer of a new generation of dental implants, its osseointegration ability should be stronger, and the implant healing period should be shorter. The preparation method should be simple, pollution-free and efficient.

The technical scheme adopted in the present invention is as follows: a highly biologically active titanium dioxide film with a micro/nano dual structure, the titanium dioxide film is composed of micron-scale grooves with a groove width of 1 μm-30 μm uniformly distributed on the entire surface and inside and outside the grooves. Uniformly distributed nano-scale holes with a diameter of less than 1 μm; two geometric structures, micro-scale grooves and nano-scale holes, overlap and distribute on the entire surface of the film; micro-scale grooves present irregular, interconnected, curved and wrinkled shapes. Divide the film material into numerous worm-like or island-like protrusions.

A preparation method of a highly biologically active titanium dioxide film with a micro/nano dual structure: first prepare a titanium metal sample, polish the working surface with sandpaper, clean it with ultrapure water, ultrasonically clean it with high-purity acetone, and dry it or dry it; The cleaned titanium metal surface is subjected to micro-arc oxidation, and the power source used is a bipolar pulse micro-arc oxidation power source; the titanium metal material is used as the anode, and the stainless steel sheet is used as the cathode, and the anode and cathode are placed in the electrolyte; the electrolyte is used in Add 0.05~0.5mol lithium tetraborate Li ₂ B ₄ O ₇ to 1000g deionized water to prepare; keep the temperature of the electrolyte below 50°C, apply a DC pulse voltage between the two electrodes, the voltage is 360~500V, and the current density is 1 ～4A/dm ² , the pulse frequency is 400～700Hz, the duty ratio is 10%～30%, the oxidation time is 1～30 minutes, and finally a titanium dioxide film with micro/nano dual structure is obtained on the titanium metal surface.

The titanium metal is industrial pure titanium or titanium-based alloy.

In the above-mentioned preparation method, the density and distribution of micron-scale grooves in the titanium dioxide film are controlled by changing the time of micro-arc oxidation, so as to ensure that the obtained titanium dioxide film micro/nano dual structure features are evenly distributed, and there is no excessive oxidation to cause thin film The phenomenon of exfoliation; reasonable selection of voltage, current density, pulse frequency and duty cycle to obtain an oxide film with a suitable micron-scale trench size and depth, so that the film has the best superhydrophilic and bioactive properties.

The beneficial technical effect of the present invention is: the preparation method of this titanium dioxide thin film is to adopt lithium tetraborate aqueous solution as electrolyte, carry out micro-arc oxidation treatment to the cleaned titanium metal surface, power supply is bipolar pulse micro-arc oxidation power supply, its The working voltage is 360-500V, the current density is 1-4A/dm2, the pulse frequency is 400-700Hz, the duty cycle is 10%-30%, and the oxidation time is 1-30 minutes. The morphology of the obtained film is as follows: uniformly dispersed micron-scale grooves and nano-scale holes are overlapped and distributed on the entire surface of the film layer. This titanium dioxide film with a micro/nano dual structure determines its special properties: the film layer has super-wetting ability, and the contact angle of water and oil is zero. It is of great significance for a new generation of dental implants that can withstand large occlusal forces and have a short healing period. The preparation process is simple, the electrolyte is pollution-free, and it is easy for large-scale production and industrial promotion.

Description of drawings

Figure 1 is the SEM microscopic topography (500 times) of titanium dioxide thin film obtained by micro-arc oxidation on the surface of pure titanium using sodium tetraborate electrolyte in the prior art.

Figure 2 is a further enlarged view of Figure 1 (4000 times).

Fig. 3 is a SEM microscopic topography view (500 times) of a titanium dioxide thin film with micro/nano dual structure characteristics prepared on the surface of pure titanium according to the technical solution of the present invention and various parameters of Example 1.

Figure 4 is a further enlarged view of Figure 3 (5000 times).

In the figure: 1. Wrinkle hole groove, 2. Nano-scale micropore, 3. Micron-scale groove, 4. Worm-shaped or island-shaped protrusion, 5. Nano-scale hole.

Figures 1 and 2 show that although the titanium dioxide film layer structure prepared by the prior art is also composed of micron-scale wrinkled pores 1 and uniformly distributed nanoscale micropores 2, the interconnection of the wrinkled pores 1 is not enough, and the nanoscale The number of micropores 2 is small and the depth is relatively shallow, so that the film layer structure is dominated by the structure of micron-scale pores 1, the micro/nano dual structure features are not obvious, and the superhydrophilic performance of the film layer cannot be fully exerted. In addition, the edges of the wrinkled pore-like structure are relatively sharp, and the transition of each region is not round, which is not conducive to the adsorption and growth of cells.

3 and 4 show that the titanium dioxide film prepared by the technical scheme of the present invention is composed of micron-scale grooves 3 uniformly distributed on the entire surface and nano-scale holes 5 uniformly distributed inside and outside the groove; micron-scale grooves 3 and nano-scale holes 5 These two geometric structures overlap and distribute on the entire surface of the film layer, forming a typical micro/nano double structure; micron-scale grooves 3 present irregular curved and wrinkled shapes, and are interconnected, thereby dividing the film layer material into Numerous worm-like or island-like protrusions4.

Detailed ways

The present invention will be further described in detail below with specific embodiments in conjunction with the accompanying drawings.

The operation steps to obtain a highly biologically active titanium dioxide film with a micro/nano dual structure on the surface of commercially pure titanium with the grade TA2 are as follows:

(1) Cleaning treatment of pure titanium substrate

The sample was cut into discs with a diameter of 10 mm and a thickness of 2 mm. Then use 800#, 1000# sandpaper to polish respectively, clean with ultrapure water, then use acetone with a concentration of 99.7% to ultrasonically clean, and dry with cold air.

(2) Micro arc oxidation

The micro-arc oxidation is performed on the cleaned pure titanium surface, and the power source used is a bipolar pulse micro-arc oxidation power source; the pure titanium sample is used as the anode, and the stainless steel sheet is used as the cathode, and the anode and cathode are placed in the electrolyte; the electrolyte uses Prepared by adding 0.1mol lithium tetraborate to 1000g deionized water; keep the electrolyte below 35°C by cooling circulating water, and apply a DC pulse voltage between the two poles, the voltage is 440V, and the current density is 3A/dm ² , the pulse frequency was 500 Hz, the duty cycle was 15%, and the oxidation time was 15 minutes.

SEM was used to observe the surface morphology of the titanium dioxide film prepared in the above examples. As shown in Figures 3 and 4, micron-scale grooves 3 (groove width 10-20 μm) and nano-scale holes 5 (aperture diameter) were evenly distributed on the obtained film. 100-300nm); micron-scale grooves 3 and nano-scale holes 5 overlap and distribute on the entire surface of the film, forming a typical micro/nano dual structure; micron-scale grooves 3 present irregular curved folds Morphology, interconnected with each other, so that the film material is divided into numerous worm-like or island-like protrusions4.

Claims (3)

1. the titanium deoxid film with micro-/ nano dual structure of a high biological activity is characterized in that: described titanium deoxid film is by being that equally distributed aperture constitutes less than the nano level hole of 1 μ m inside and outside the micron order groove of 1 μ m-30 μ m and the groove in equally distributed groove width on the whole surface; These two kinds of geometry overlap population of micron order groove and nano level hole are at whole film surface; The flexural fold shape form that the micron order groove presents is random, interconnect is divided into numerous vermiforms or island projection with film material.

2. the preparation method of the titanium deoxid film with micro-/ nano dual structure of a kind of high biological activity according to claim 1, it is characterized in that: at first produce the titanium metal sample, use the sand papering working face, ultrapure water cleans, high pure acetone ultrasonic cleaning dries up or dries; Surface of metal titanium to clean is carried out differential arc oxidation, and the power supply that adopts is the bipolar pulse mao power source; Titanium metal material is anode, and stainless steel substrates is negative electrode, and anode and negative electrode are put into electrolytic solution; Electrolytic solution adopts and add the preparation of 0.05～0.5mol lithium tetraborate in the 1000g deionized water; The temperature of electrolytic solution remains on below 50 ℃, dc pulse voltage in addition between the two poles of the earth, and its voltage is 360～500V, current density is 1～4A/dm ², pulse-repetition is 400～700Hz, and dutycycle is 10%～30%, and oxidization time is 1～30 minute, at last the titanium deoxid film that has the micro-/ nano dual structure in the surface of metal titanium acquisition.

3. the preparation method of the titanium deoxid film with micro-/ nano dual structure of a kind of high biological activity according to claim 2, it is characterized in that: described titanium metal is industrially pure titanium or titanium base alloy.

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