KR20100076867A - Etching and biocompatible thin film coated methods for surface of implant - Google Patents

Abstract

PURPOSE: A surface treatment of medical implant and a technology of coating of biocompatible thin film are provided to prevent the nucleation of the calcium phosphate and to promote the formation of the calcium phosphate. CONSTITUTION: A surface treatment of medical implant and a technology of coating of biocompatible thin film include: a step of manufacturing PH 0.05-6.0 of acidic aqueous solution which has calcium ion, phosphate ion, and materials inhibiting the nucleus generation of calcium phosphate; a step of dipping the implant for half an hour to 100 hours; a step of reacting the mixed solution while increasing the temperature of the aqueous solution to 30-150 deg.C after adding alkaline aqueous solution to the aqueous solution and controlling it at pH 9.0 - 14.0; and a step of drying and washing the implant coated with calcium phosphate.

Description

Medical implant surface treatment and biocompatible thin film coating technology {Etching and Biocompatible Thin Film Coated Methods for Surface of Implant}

The present invention relates to an increase in the surface roughness of an implant and a method for producing an implant coated with a biocompatible thin film. Implants are used in dentistry and orthopedics as a substitute to recover tissue loss in the human body. Titanium with excellent mechanical strength and no rejection to the human body is mainly used to replace the tooth root of the missing tooth as well as the aesthetic effect of the damaged tooth of the human body. In order to increase the reactivity between the titanium implant, which is a bioinert material, and the tissue, the surface of the implant is made to be appropriate or the biocompatible thin film is coated to treat the implant surface to facilitate the fusion with bone or tissue. In order to increase the biocompatibility of the double implant surface, a thin film of calcium phosphate is coated on the implant surface. Calcium phosphate is a material that is physically and chemically identical to the minerals that make up bones and teeth in the human body, and shows direct binding to bones and surrounding cells. That is to modify the surface of the implant or to coat the surface of the implant with a bioactive material. As such, milling, acid treatment, spray coating, and ionized surface methods are used as a method of enhancing the reactivity of the implant with biological tissues.

As a method of modifying the implant surface, milling, acid treatment, spray coating, ionized surface method and the like are used as a method of increasing the surface roughness or coating a bioactive material on the implant surface. In addition, Machined (Smooth) surface implant by machining according to the surface treatment method, Titanium plasma sprayed surface implant coated by spray spraying titanium at high temperature, Hydroxyapatite coated implant coated with calcium phosphate as bioactive material, Surface by acid treatment Acid modified etched surface implant, Sandblasting with acid etched surface implant after surface modification using metal grains at high pressure, Acid-treated RBM (Resorbable Blast Media) surface after surface modification by spraying ceramic at high pressure Implants, Sintered Porous-surface Implants with Titanium Granules Bonded at High Temperature. Hydroxyapatite coated implant is a method of surface treatment of calcium phosphate with an implant coated with calcium phosphate, which has the best bonding ability to bone and tissue on the surface. Plasma Spraying, Sputtering, Sol-gel (Sol-Gel) method, ion implantation method, ion beam deposition method, etc. are used.

The present invention is a method of forming a thin film of biophosphate calcium phosphate on the surface after surface modification that increases the surface roughness of the implant. In general, in order to modify the implant surface and to coat the calcium phosphate thin film, each step of manufacturing the implant surface and the process of coating the implant surface with calcium phosphate are performed. That is, in order to modify the implant surface, a method such as RBM which performs a strong acid treatment process and many washing processes or sprays the implant surface at a high pressure using silica or calcium phosphate particles is required. In addition, a method for coating a calcium phosphate thin film on the surface of the implant is required to prepare a calcium phosphate powder or plate for the implant coating and to deposit it on the implant surface. However, in the case of the calcium phosphate thin film coating, the modification of the coated calcium phosphate may occur due to high heat, and since the surface modification process and the calcium phosphate thin film coating process are performed, a complicated process and a high cost are required. Therefore, process improvement for implant surface modification and calcium phosphate thin film coating has been studied separately.

In the case of domestic patent 10-0453289, domestic patent 10-0611945, and domestic patent 10-0775537, the calcium phosphate thin film is formed on the surface of the implant by the hydrothermal treatment method, so that the modification of calcium phosphate can be prevented. There is a disadvantage that only possible and inherent surface modification is not possible. However, in the present invention, since it is possible to form a calcium phosphate thin film on the surface of the implant at a lower temperature than the high temperature deposition method or hydrothermal treatment, the modification of the calcium phosphate thin film can be prevented. In addition, in the case of Korean Patent No. 675573 and Korean Patent No. 388074, a method of forming a calcium phosphate thin film on the surface of an implant in an aqueous solution may be manufactured at a low cost in a relatively simple process. However, there is a disadvantage that the surface modification effect to increase the surface roughness of the implant is not obtained. In addition, since the calcium phosphate thin film is coated on the implant in a neutral atmosphere in the range of pH 6.0 ~ 8.0, the bonding strength between the implant and the calcium phosphate thin film is weak, so it is easily peeled off when handling or implanting the implant. Therefore, a plasma spray method, a sputtering method, an ion implantation method, an ion beam deposition method, and the like, which form a calcium phosphate thin film while high heat is applied to the implant surface, are generally used to increase the bonding force between the implant and the calcium phosphate thin film. However, the present invention is to increase the surface roughness of the implant with the implant and the calcium phosphate thin film has a high binding force because it is possible to coat the calcium phosphate thin film in an alkaline atmosphere of pH 9.0 ~ 14.0. This is because a large number of hydroxyl groups (OH groups) present in the aqueous alkali solution are strongly bonded to the implant surface on the surface of the metallic implant having increased surface roughness in the aqueous alkali solution, and thus the calcium phosphate thin film is formed on the surface thereof, so that the calcium phosphate thin film is hardly peeled off. . In general, it is difficult to prevent the formation of calcium phosphate even if the pH of the aqueous solution in which calcium and phosphate ions are mixed is increased. This is because the calcium phosphate compound is easily produced by increasing the pH of the aqueous solution containing calcium and phosphate ions. Therefore, Korean Patent No. 675573 and Korean Patent No. 388074 select the method of reducing the reactivity as much as possible by the low concentration of ions of calcium and phosphoric acid and the method of removing the microcrystals reacted through the filter. In order to form, a method of slowly forming and growing calcium phosphate nuclei on the implant surface at a temperature of 0 to 40 ° C is used, which requires a long time and is difficult to form a calcium phosphate thin film on a large amount of implant surface. However, in the present invention, since a high concentration of the aqueous solution is used together with the surface modification effect of increasing the roughness of the calcium phosphate implant surface, the calcium phosphate thin film may be coated on a large amount of the implant surface at one time. In addition, since the calcium phosphate thin film is prepared at a high pH of pH 9.0 to 14.0, phosphoric acid finer than the above-described invention (National Patent No. 675573 and Korean Patent No. 388074), which produced the calcium phosphate thin film at a concentration of pH 6.0 to 8.0. A coating layer made of calcium crystals can be obtained. In addition, since the calcium phosphate thin film coating is formed on the surface of the implant by increasing the temperature, the crystallinity of the calcium phosphate thin film can be adjusted according to the temperature control, thereby controlling the rate of absorption and binding to the biological tissue during the transplantation. In addition, since the surface modification was made during the implantation of the living body, the biological tissue is rapidly bound by the calcium phosphate coated on the implant, and even after the calcium phosphate coating layer is absorbed, the surface-modified implant surface and the biological tissue can be more strongly bound. Therefore, the method of the present invention is an economical implant manufacturing method in a very simple process that can simultaneously modify the surface by the implant surface roughness, coating the calcium phosphate thin film coating on the implant surface and control the thickness and crystallinity of the calcium phosphate coating layer .

     The present invention relates to a method for manufacturing an implant for enhancing the adhesion to biological tissues, and more particularly to the surface modification of the implant surface to increase the surface roughness and to have a high surface activity and to the surface of the implant calcium phosphate thin film as a biocompatible material A method of coating.

     According to the present invention, an acidic aqueous solution having a pH of 0.05 to 6.0 containing calcium ions, phosphate ions, and calcium phosphate nucleation inhibitors is prepared [step (1)], and the process of immersing the implant for 30 minutes to 100 hours [step (2) After the alkaline solution is added to the aqueous solution to adjust the pH to 9.0 to 14.0, the reaction is performed while increasing the temperature of the aqueous solution to 40 to 150 degrees [step (3)] to wash and dry the implant coated with calcium phosphate. It provides a medical implant surface treatment and biocompatible thin film coated implant, characterized in that consisting of a step. It may also include the step of heat-treating the implant to control the rate of absorption and absorption with biological tissue.

     In step (1), an acidic aqueous solution having a pH of 0.05 to 6.0 containing calcium ions, phosphate ions and calcium phosphate nucleation inhibitors is prepared. The molar concentration of calcium ions and phosphate ions is set at 0.01M to 0.5M, respectively. At this time, the molar ratio of calcium / phosphorus ions is 0.5 to 2.5, and most preferably the molar ratio of calcium / phosphate ions is 1.5 to 2.0, the molar concentration of calcium and phosphate ions is 0.01 to 0.1M, and the pH is 0.05 to 2.0. It is. The calcium phosphate nucleation inhibitor is a substance containing a carboxyl group that inhibits nucleation and growth of calcium phosphate by a carboxyl group. The content of the calcium phosphate nucleation inhibitor added to the aqueous solution is 0.1wt% ~ 200wt% and most preferably 10wt% ~ 100wt%. In step (2), the implant is immersed in the acidic aqueous solution of step (1) for 30 minutes to 100 hours, and the implant is immersed in the aqueous acidic solution and stirred. The stirring time is most preferably 12 to 48 hours. Immersion and immersion of the implant in an acidic aqueous solution for a sufficient time increases the surface roughness of the implant by the acidic aqueous solution, which has a surface modification effect and increases the binding force with the biological tissue. In this case, when the acidic aqueous solution is reacted at a temperature of 30 to 100 degrees, a better surface modification effect can be obtained. In addition, the coating surface of the calcium phosphate thin film can be obtained a more excellent coating effect due to the rough surface. In step (3), an alkaline aqueous solution is added to the aqueous solution of step (2) to adjust the pH to 9.0 to 14.0, and pH 10-12 is most preferred. The knowledge of those skilled in the art to which the present invention belongs is somewhat different depending on the molar concentrations of calcium and phosphate ions, but the calcium and phosphate ions of the present invention before the pH 9.0 calcium phosphate in the aqueous solution itself It is impossible to form a calcium phosphate coating layer on the surface of the implant because fine crystals of is formed. However, even if the pH is 9.0 to 14.0 in step (3) of the present invention, the reason why calcium phosphate crystals are not produced in the aqueous solution itself is that the carboxyl group, a calcium phosphate nucleation inhibitor, prevents nucleation and growth of calcium phosphate in step (1). Because it inhibits. In addition, by controlling the addition amount of the carboxyl group in accordance with the concentration of calcium ions and phosphate ions can prevent the nucleus growth of calcium phosphate in the aqueous solution for a long time. In step (4), the reaction is carried out while increasing the temperature of the aqueous solution of step (3) from 40 degrees to 150 degrees, most preferably from 60 to 80 degrees. At this time, as the temperature of the aqueous solution increases, the surface roughness is increased because it inhibits the function of the carboxyl group that inhibits the nucleation of calcium phosphate and promotes the nucleation of calcium phosphate by calcium ions and phosphate ions. The calcium phosphate thin film coating layer is gradually formed on the surface. In addition, the hydroxyl group (OH group) present in the alkaline aqueous solution of pH 9.0 ~ 14.0 is attached to the implant surface and forms a calcium phosphate thin film coating layer on the surface while strong bonding with the calcium phosphate nuclei. That is, the surface roughness is increased, and calcium ions are bonded to the surface of the implant with the modified surface by the hydroxyl group (OH group) present in the alkaline aqueous solution, and phosphorus ions are combined with it to form a very thin calcium phosphate coating film on the implant surface naturally. Since strong bonding force is formed between the implant and the calcium phosphate thin film, it is possible to prevent the delamination of the calcium phosphate coating film generated during handling for the procedure or during the implant procedure in the living tissue. Also in the common knowledge of the present invention the crystal (particle) size of calcium phosphate is determined by the pH of the aqueous solution together with the concentrations of calcium and phosphate ions and the crystallinity is determined by the production temperature. The crystal (particle) size decreases with higher concentrations of calcium and phosphate ions and pH, and the crystallinity increases with higher production temperature. Therefore, the calcium phosphate thin film coating formed on the implant surface is formed on the implant surface through the wide range of pH 9.0 to 14.0 in step (3) and the temperature of 40 to 150 degrees. And crystallinity. In addition, if the crystal (particle) size of the calcium phosphate thin film coating formed on the implant surface can be controlled, the thickness of the coated calcium phosphate thin film can be controlled, which means that the rate of decomposition in biological tissue can be controlled. The final step is to wash and dry the coated implant, and then sufficiently washed and dried to increase the surface roughness, thereby preparing an implant coated with a calcium phosphate thin film on which the surface of the implant is modified. In addition, when the implant coated with the calcium phosphate thin film is heat treated at 150 degrees to 1100 degrees, the crystallinity of the coated calcium phosphate can be controlled. As the heat treatment temperature increases, the crystallinity of the calcium phosphate film increases. In general, as the crystallinity of the calcium phosphate coating film formed on the implant surface increases, it takes longer to bind and dissolve the bone and tissue. That is, the crystallinity of the calcium phosphate thin film can be controlled by controlling the temperature of forming the calcium phosphate thin film on the surface of the implant in step (3), and secondly, the implant coated with the calcium phosphate thin film is heat-treated again at 150 to 1100 degrees. Since the crystallinity of the calcium thin film can be further increased, the calcium phosphate thin film coating layer having more diverse crystallinity can be manufactured. Therefore, an implant coated with a calcium phosphate thin film having various decomposition rates in biological tissues can be prepared. This can be usefully used for the coating of artificial auxiliary implanted in living tissue. This is because it is necessary to adjust the binding rate and degradation rate with biological tissues according to the implantation site of the artificial auxiliary implanted. Therefore, by using the present invention, it is possible to easily coat the calcium phosphate thin film on the surface of other metals, ceramics, and polymers as well as implants.

The method of the present invention is very economical because it can be manufactured by a simple process and equipment for surface modification and coating of calcium phosphate thin film by increasing the surface roughness of the implant and compared with the thermal evaporation or hydrothermal treatment method. Because it is made at low temperatures, no impurities other than calcium phosphate are produced. In addition, it is possible to control the microcrystalline size of the calcium phosphate thin film coating layer, the thickness of the thin film and the crystallinity of the thin film on the implant surface, and to control the rate of absorption to the living body. The surface roughness can be increased after being absorbed into biological tissue to achieve a strong bond with the surface modified implant. In addition, the method of the present invention enables the production of a thin layer of calcium phosphate on the surface of metal implants and polymers and ceramic materials for human implantation, such as dental implants, knee implants, screw-type implants, and the like, as well as dental implants.

The following examples of the present invention are described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples.

≪ Example 1 >

     Calcium Nitrate and Ammonium Phosphate were quantified in 100 ml of 0.5M Citric Acid Aqueous Solution to prepare 0.5M Citric Acid-0.05M Calcium Nitrate-0.03M Ammonium Phosphate aqueous solution, and then the calcium phosphate nucleation inhibitor was added to 50 wt%. The aqueous solution of (1) is manufactured. In addition, 0.5M sodium hydroxide solution is prepared.

≪ Example 2 >

     The implant is immersed in 500 ml of the aqueous solution of step (1) prepared in Example 1 and stirred for 24 hours. The stirred implant is also washed with distilled water and dried. 1 shows an electron micrograph of the surface of the implant prepared in Example 2.

<Example 3>

     The implant is immersed in 300 ml of the aqueous solution of step (1) prepared in Example 1 and stirred for 12 hours. After stirring, the pH of the 0.5M Citric Acid-0.05M Calcium Nitrate-0.03M Ammonium Phosphate aqueous solution was adjusted to 12 by adding 0.5M Sodium Hydroxide aqueous solution to the aqueous solution. Heat was added to the aqueous solution adjusted to pH 12 so that the temperature of the aqueous solution was 70 degrees and reacted for 6 hours. The reacted implant is washed five times with distilled water and dried in a drier at a temperature of 100 degrees. 2 shows an electron micrograph of the surface of the implant prepared in Example 3.

Phosphoric acid on the surface of metal implants and polymer and ceramic materials for human implants, such as dental implants, hip implants, knee joint implants, screw-type implants, etc. The calcium thin film layer can be formed.

     Figure 1 shows a scanning electron micrograph of the surface of the implant prepared in Example 2.

     Figure 2 shows a scanning electron micrograph of the calcium phosphate thin film coating layer of the implant surface prepared in Example 3.

Claims (6)

     After preparing an acidic aqueous solution having a pH of 0.05 to 6.0 containing calcium ions, phosphate ions and calcium phosphate nucleation inhibitors [step (1)], and immersing the implant for 30 minutes to 100 hours [step (2)]. After adding an alkaline aqueous solution to the aqueous solution to adjust the pH to 9.0 to 14.0, the reaction temperature is increased to 30 degrees to 150 degrees and reacted (step (3)) to wash and dry the implant coated with calcium phosphate. Surface Treatment of Implants and Coating Methods of Biocompatible Thin Films      The method of claim 1, wherein the calcium phosphate nucleation inhibiting material as a substance containing a carboxyl group and the implant surface treatment and pyrophosphate coating method      The method of claim 1, wherein the aqueous solution after step (2) is replaced with the aqueous solution of step (1) and the step (3) is performed.      According to claim 1, wherein the surface treatment of the implant and coating method of the biocompatible thin film comprising the step of cooling after the temperature of the acidic aqueous solution in step (2) to 30 ℃ ~ 150 ℃      Method of coating a calcium phosphate thin film on the metal, ceramic, polymer surface by the method of claim 1      Method of heat-treating the calcium phosphate thin film coated by the method of claim 1 at 150 to 1100 degrees

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