KR20040099964A - The biocompatible implant on which is coated with hydroxyapatite/titania double layer - Google Patents

Abstract

PURPOSE: A biocompatible implant on which is coated with hydroxyapatite/titania double layer is provided to induce a fast synostosis and to have a surface corrosion resistance and a surface abrasion resistance. CONSTITUTION: The biocompatible implant on which is coated with hydroxyapatite/titania double layer comprises a titanium substrate, an inner layer having a titania coating layer and an outer layer having a hydroxyapatite layer. The biocompatible implant is obtained by a surface treatment method comprising preparing a hydroxyapatite sol and a titania sol and coating the Ti substrate with the hydroxyapatite sol and the titania sol.

Description

The biocompatible implant on which is coated with hydroxyapatite / titania double layer}

The present invention relates to an implant coated on the surface by using a plurality of coating materials that can support the bone adhesion, and improve the mechanical properties of the implant for biological use, more specifically, a bio-implant excellent in mechanical properties (mechanical properties) Titanium for bio-implants with a double layer coating of hydroxyapatite (HA) as an outer layer on a titanium (Ti) metal substrate and a titania as an inner layer. It is about.

The human body can easily corrode metals. Titanium (Ti) for bio-implants is close to the environment of human bones and has excellent biocompatibility, excellent mechanical properties, and reactions with biological tissues. It is widely used as a biomaterial for implants not only in the field of dental medicine but also in the field of orthopedics.

Recently, many attempts have been made to physically and chemically improve the surface of the titanium for bio implants in order to promote the oseointegration. Sand blasting or acid etching can be used to change the physical properties of the surface or to coat the surface with a material that is chemically different from titanium. There may be a variety of materials to be coated, but the coating of the apatite hydroxide is reported to induce a faster bone adhesion when the implant is implanted into bone tissue.

On the other hand, attempts have been made to increase the biocompatibility by coating the surface of titanium for biological implants with titania (TiO ₂ ). The material of the implant must be free from corrosion, degradation, absorption, etc. in the living body, and must be mechanically strong enough to withstand mastication pressure.

Pure titanium (purity 99.5%), which is the main material for current implants, can react with body fluids in vivo by itself, resulting in surface changes such as corrosion and decomposition absorption. In general, an oxide film is spontaneously formed on the titanium surface in the body fluid to prevent decomposition in the human body, and wear resistance and corrosion resistance are enhanced. However, the oxide film spontaneously formed on the surface of titanium is so thin that its abrasion resistance and corrosion resistance are not sufficient. Therefore, an attempt is made to artificially form a titania layer on the surface of titanium to increase corrosion resistance and further increase biocompatibility. have.

As the results of the study show that bone adhesion increases as the surface roughness increases, sandblasting is used as a means to increase surface roughness, and blasting using titania is the most popular medium. It is used.

However, a method of using alumina (Al ₂ O ₃ ) has also been attempted because only the method of blasting titania does not satisfy the required surface roughness. However, the method using alumina has the advantage of increasing the surface roughness, but since the effect on the living body of the alumina present on the surface of the implant is not yet fully identified, it is not actually used in clinical practice.

On the other hand, the thin titania film naturally formed on the surface of titanium increases the adhesion strength between titanium and apatite in the process of coating apatite on the surface of titanium, but it is not thin enough to maintain the adhesion strength. There is a disadvantage. Therefore, there is a need to strengthen the titania coating layer inside the apatite hydroxide layer in coating the apatite hydroxide.

The present invention has been made to solve the above problems, by using a surface coating method of the surface treatment method of titanium for biological implants at the same time to form an apatite hydroxide / titania bilayer at the same time the outer layer is excellent tissue reaction by apatite hydroxide Induces rapid bone adhesion through the inner layer, the inner layer is intended to provide titanium for bio-implants that the surface of the titanium for bio-implants has a corrosion resistance and wear resistance by titania.

In addition, the objective of the present invention is to provide a titanium for a bio-implant in which the titania coating layer is inserted between the apatite hydroxide and titanium, thereby improving the low adhesion between the conventional apatite hydroxide coating layer and titanium.

1 is a diagram showing a coating of a bilayer of an apatite hydroxide outer layer and a titania inner layer on a titanium substrate.

2 is a scanning electron micrograph of apatite hydroxide / titania bilayer coated on a titanium substrate.

3 is a graph showing phase analysis of an apatite hydroxide / titania bilayer coated on a titanium substrate using an X-ray diffraction method.

4 is a graph showing the adhesion strength of the apatite hydroxide / titania bilayer and the apatite hydroxide monolayer coated on the titanium substrate.

FIG. 5 is a scanning electron micrograph showing the proliferation of osteoblasts grown for 5 days on apatite hydroxide / titania bilayer coated on a titanium substrate.

Figure 6 is a graph showing the proliferation rate of osteoblasts grown on a titanium substrate for 10 days.

7 is a graph showing the differentiation rate of osteoblasts grown on a titanium substrate for 10 days.

The present invention relates to an implant coated on the surface by using a plurality of coating materials that can support the bone adhesion, and improve the mechanical properties of the biological implant, more specifically, the biological implant having excellent mechanical properties (mechanical properties) Titanium for bio-implants with a double layer coating of hydroxyapatite (HA) as an outer layer on a titanium (Ti) metal substrate and a titania as an inner layer. In order to simplify the coating process and to form a high quality coating film, apatite hydroxide and titania are prepared using the sol-gel method.

The coating method according to the present invention comprises the steps of preparing a hydroxyapatite sol, preparing a titania sol, coating a titania layer on a titanium substrate, heat-treating the titanium for the bio-implant coated with titania, to the titania Coating a layer of apatite hydroxide on the coated titanium for bio-implant and heat-treating the titanium for bio-implant coated with the hydroxide apatite.

Preferred embodiments of the titanium surface treatment method for a biological implant according to the present invention will be described in detail with reference to the accompanying drawings.

The system of the present invention consists of a double coating of an apatite hydroxide outer layer and a titania inner layer on a titanium substrate as shown in FIG.

Figure 2 shows a scanning electron micrograph showing the cross-sectional shape of the apatite hydroxide / titania bilayer formed by the sol-gel method on the titanium substrate in accordance with an embodiment of the present invention. As shown schematically in FIG. 1, the bilayer structure of the apatite hydroxide outer layer and the titania inner layer is clearly shown. The thickness of each layer was found to be about 800 nm for the apatite hydroxide layer and about 200 nm for the titania layer.

Both the outer layer of apatite hydroxide and the inner layer of titania show a very uniform and dense microstructure, and no cracks or peelings are found inside the coating layer or at each interface.

Figure 3 is a graph showing the phase of the apatite hydroxide / titania bilayer formed by the sol-gel method on the titanium substrate as an embodiment according to the present invention using the X-ray diffraction method (X-ray diffraction method). As can be seen from the peaks, the peaks of the apatite hydroxide phase and the titania phase are clearly shown, indicating that each phase is formed correctly.

In FIG. 4, the adhesion strengths of the apatite hydroxide / titania bilayer and the apatite hydroxide monolayer formed by the sol-gel method on the titanium substrate as an embodiment according to the present invention are shown graphically according to the heat treatment temperature. At the heat treatment temperature of 450 ° C. or higher, the bilayer into which titania is inserted as an intermediate layer shows a value of about 60% or more higher than that of a single layer containing only apatite hydroxide. When the heat treatment at 500 ℃ it can be seen that the strength of the double layer shows the highest value of 55MPa. This high adhesion strength in the bilayer is believed to be due to the good chemical affinity of titania inserted into the intermediate layer with not only titanium but also apatite hydroxide.

Figure 5 shows the proliferation of the cells after culturing the HOS cells on the bilayer for 5 days in order to determine the cell reaction characteristics of the apatite hydroxide / titania bilayer formed by the sol-gel method on the titanium substrate in accordance with an embodiment of the present invention. It can be seen that the cells grow very well on the coating layer.

FIG. 6 is a graph measuring the number of HOS cells grown after a 7-day incubation on apatite hydroxide / titania bilayer, showing the incubation in pure titanium and titanium coated only with titania. Compared to pure titanium, the titania single coating and the apatite hydroxide / titania bilayer have more cell numbers.

7 is a graph measuring alkaline phosphatase (ALP) activity after culturing cells on apatite hydroxide / titania bilayers for 10 days to measure the degree of differentiation of cells. The differentiation stage of the cells is a post-proliferation stage of the cells during the bone formation process, indicating the activity of the cells and the function of the bone formation, ALP activity is an important indicator of this cell differentiation. Compared with pure titanium, the coating with titania showed a high rate of differentiation, and the bilayer coated with hydroxide apatite showed a higher rate of differentiation. This demonstrates that biocompatibility can be enhanced by coating with apatite hydroxide / titania bilayer on a titanium substrate.

Hereinafter, the embodiment according to the present invention will be described in detail.

<Example 1>

A process for preparing a hydroxyapatite sol is a step of dissolving Ca (NO ₃ ) ₂ · 4H ₂ O, a raw material of calcium (Ca) in ethanol (C ₂ H ₅ OH) and stirring to prepare a calcium solution, and phosphorus (P) Preparing a phosphorus solution by dissolving P (CH ₃ CH ₂ O) ₃ and distilled water (H ₂ O), which are the raw materials, in ethanol (C ₂ H ₅ OH), followed by stirring, and mixing the calcium solution and the phosphorus solution. And then stirring and aging the solution.

The mixed solution of the calcium solution and the phosphorus solution is characterized in that the calcium: phosphorus is mixed in a molar ratio of 1.67, the solution is aged at room temperature for 60 hours to 80 hours and then again at 35 ℃ to 45 ℃ 20 hours to 30 It is characterized by aging for time.

<Example 2>

The manufacturing process of titania sol was prepared by mixing Ti (OCH ₂ CH ₂ CH ₃ ) _2, which is a titanium (Ti) raw material, with a solution containing ethanol (C ₂ H ₅ OH) and diethanolamine [(HOCH ₂ CH ₂ ) ₂ NH]. Adding and mixing; and stirring the mixed solution, followed by adding distilled water and then stirring.

The ethanol (C ₂ H ₅ OH) and diethanolamine [(HOCH ₂ CH ₂ ) ₂ NH] is characterized in that the mixture at a volume ratio of 5: 1.

<Example 3>

Coating the titania inner layer includes applying a titania sol to the titanium substrate for bio-implant to wet the titanium substrate, spin using a spin coater, drying the titanium substrate coated with titania sol, and drying Heat-treating the titanium substrate.

The spin coating machine is used to spin for 10 seconds to 30 seconds at a speed of 2,500 to 3,500 rpm, and the drying is performed for 5 to 7 hours at 70 ℃ to 90 ℃, the heat treatment is 500 It is characterized by performing for 1 hour at ℃.

<Example 4>

The coating of the outer layer of apatite hydroxide may be performed by applying a titania sol to a titanium substrate for biological implants to wet the titanium substrate, spinning using a spin coater, drying the titanium substrate coated with titania sol, and And heat treating the dried titanium substrate.

The spin coating machine is characterized in that the spin for 20 seconds at a speed of 3000 rpm, the drying is characterized in that for 6 hours at 80 ℃, the heat treatment at 400 ℃ to 600 ℃ for 1 hour to 2 hours It is characterized by performing.

The present invention is not limited to those illustrated by the above detailed description and illustrated in the following drawings, and various modifications can be made as examples within the description of the claims.

As disclosed in the present invention, it is possible to induce high biocompatibility by providing titanium for a bio-implant coated with apatite hydroxide / titania bilayer, and also by placing a titania interlayer between titanium for a bio-implant and apatite hydroxide. The adhesion strength to the titanium substrate can be increased and a thin, uniform and dense film can be formed by using the sol-gel method as a coating process.

Claims (11)

Apatite hydroxide sol and titania sol are prepared and prepared by the surface treatment method of an implant for a living body comprising coating the apatite hydroxide sol and the titania sol so that the inner layer comprises a titania coating layer and the outer layer is apatite hydroxide. Biological implant coated with apatite hydroxide / titania bilayer characterized in that it comprises a coating layer. The method of claim 1, The apatite hydroxide sol is, Ca (NO ₃ ) ₂ .4H ₂ O, a raw material of calcium (Ca), was dissolved in ethanol (C ₂ H ₅ OH) and stirred to prepare a calcium solution, and P (CH ₃ CH ₂ , a raw material of phosphorus (P), was prepared. O) ₃ and distilled water (H ₂ O) is dissolved in ethanol (C ₂ H ₅ OH) and stirred to prepare a phosphorus solution, the calcium solution and the phosphorus solution is mixed, stirred and aged to prepare A biocompatible implant coated with apatite hydroxide / titania bilayer. The method of claim 2, The mixed solution of the calcium solution and the phosphorus solution is a biological implant coated with apatite hydroxide / titania bilayer, characterized in that the calcium: phosphorus is mixed in a molar ratio of 1.67. The method of claim 2, The solution is aged for 60 hours to 80 hours at room temperature, and then aged for 20 hours to 30 hours at 35 ℃ to 45 ℃ again biocompatible implant coated with apatite hydroxide / titania bilayer. The method of claim 1, The titania sol, Ti (OCH ₂ CH ₂ CH ₃ ) ₂ , which is a titanium (Ti) raw material, is added to a mixed solution of ethanol (C ₂ H ₅ OH) and diethanolamine [(HOCH ₂ CH ₂ ) ₂ NH], followed by mixing After stirring the mixed solution, distilled water is added, and then prepared by stirring the biological implant coated with apatite hydroxide / titania bilayer. The method of claim 5, wherein The ethanol (C ₂ H ₅ OH) and diethanolamine [(HOCH ₂ CH ₂ ) ₂ NH] is a biological implant coated with apatite hydroxide / titania bilayer, characterized in that the volume ratio of 5: 1. The method of claim 1, Biometric implant coated with apatite hydroxide / titania bilayer characterized in that the spin coating of the titania layer on the titanium substrate. The method of claim 7, wherein Biological implant coated with apatite hydroxide / titania bilayer, characterized in that spin for 10 seconds to 30 seconds at a speed of 2,500 to 3,500 rpm using the spin coating machine. The method of claim 7, wherein The drying is a biological implant coated with apatite hydroxide / titania bilayer, characterized in that performed for 5 to 7 hours at 70 ℃ to 90 ℃. The method of claim 7, wherein The heat treatment is a biological implant coated with apatite hydroxide / titania bilayer, characterized in that performed for 1 hour to 2 hours at 400 ℃ to 600 ℃. The method of claim 1, Coating the apatite hydroxide layer on the titanium substrate for bio-implantation and heat treatment coated with titania is carried out in the same manner as described in claims 7 to 10 coated with apatite hydroxide / titania bilayer Bio Implants.