KR20180004418A - A membrane and a manufacturing method for the implant - Google Patents

Abstract

The present invention relates to a membrane for implant and a manufacturing method thereof. The technological point of the present invention is to include: a step of forming titanium oxide nanotube by anodizing a membrane body formed of titanium metal (Ti) or titanium alloy (Ti alloy); and a step of forming a groove on the surface of the membrane body by removing the titanium oxide nanotube. Consequently, the present invention can obtain the membrane for implant in which an inner wall surface area has a rough surface and an outer surface area has a smooth surface. In addition, the present invention prevents leakage from the inside of a living body and can remove residual impurities on the surface during peeling by forming a groove on the surface by removing an anodized surface after anodizing the surface of a membrane body and peeling off the anodized titanium oxide nanotube. The present invention also has excellent biocompatibility, chemical suitability, and mechanical suitability when being implanted into a living body by a groove formed by anodizing the surface by using Ti alloy or titanium for body implant as a material of the membrane body.

Description

[0001] The present invention relates to a membrane for implantation,

The present invention relates to a membrane for an implant and a method of manufacturing the same, and more particularly, to an implant membrane having an inner wall surface area having an rough surface and an outer wall surface area having a smooth surface through anodization, and a method for manufacturing the same.

Biodegradable metals have superior strength, fatigue resistance and molding processability compared to other materials such as ceramics and polymer. Therefore, dental, orthopedic or orthopedic devices for the purpose of regeneration and treatment of defects, It is the most widely used biomaterial in plastic surgery. Such bioactive metals include magnesium (Mg), calcium (Ca), phosphorus (P), zinc (Zn), iron (Fe), chromium (Cr), nickel (Ni), stainless steel, cobalt (Ti), Ti alloy, zirconium (Zr), niobium (Nb), tantalum (Ta), gold (Au) and silver (Ag) Titanium or titanium alloy, which is superior in corrosion resistance and stable even in a human body tissue, is most widely used in the human body.

As a typical product manufactured using such a bioactive metal, there is an implant. Among them, a dental implant is the most widely used. The dental implant procedure is generally accomplished by incising the patient's gums, inserting an implant prosthesis into the alveolar bone in the alveolar bone, and attaching an artificial tooth to the artificial tooth. It is already well known that when the implant is placed in the alveolar bone, the initial fixation of the implant becomes high when the surrounding bone is sufficient, and the prognosis of the implant, such as long-term safety, is increased. However, there are frequent cases of bone defect that is not enough in the surrounding bone. In this case, prognosis after implant placement is unstable. Therefore, in general, the procedure to increase the alveolar bone sufficiently through tissue and bone regeneration procedure is performed. For the periodontal surgery aimed at inducing bone tissue regeneration, a transplantable biodegradable product called a membrane is used. It is used to form a space through the membrane and to move the regenerated tissue to another site and to block the penetration of the epithelial cells into the regenerated tissue for a period of time that allows tissue and bone regeneration.

In the case of the membrane used in the implant treatment, the inner wall surface should have a surface having high bio-affinity so that the tissue and bone regeneration can be smoothly performed. The outer wall surface of the membrane should be protected from blocking with other epithelial cells, It should have a smooth surface. A surface having a high biocompatibility means a surface including an appropriate roughness for smoothly regenerating the tissue on the surface and increasing the adhesion with the tissue.

Korea Patent Office Registration No. 10-0402266 Korea Patent Office Registration No. 10-0875069 Korea Patent Office Registration No. 10-1128059

It is therefore an object of the present invention to provide an implant membrane having an inner wall surface area of the membrane through anodic oxidation having a rough surface and an outer wall surface area having a smooth surface, and a method for manufacturing the same.

Also, the anodized surface of the membrane body is anodized and then the anodized surface is removed to form a groove on the surface. The anodized titanium oxide film is peeled off to prevent it from flowing out from the inside of the living body, and at the same time, And to provide a membrane for a removable implant and a method of manufacturing the same.

In addition, the membrane for implant has excellent biocompatibility, chemical suitability and mechanical suitability when the biodegradable titanium or titanium alloy is used as a material of the membrane main body and is implanted into a living body by a groove formed through surface anodization, and a manufacturing method thereof .

The above object is achieved by an anodizing a membrane body made of a titanium metal (Ti) or a titanium alloy to form titanium oxide nanotubes; And removing the titanium oxide nanotubes to form a groove on the surface of the membrane body.

Forming a polymer protective layer on the outer wall surface of the membrane body to prevent anodic oxidation of the outer surface of the membrane body prior to forming the titanium oxide nanotubes, The polymer protective layer may be formed of a material selected from the group consisting of PDMS (Polydimethylsiloxane), PMMA (Polymethylmethacrylate), PI (Polyimide), PET (polyethylene terephthalate), PES (Polyurethane), polyamide (PA), fiber reinforced plastic (FRP), and mixtures thereof.

Further comprising the step of heat treating the membrane body to form an oxide film having a thickness of 10 to 1,000 nm on the surface of the membrane body after forming the groove on the surface of the membrane body, .

In addition, the step of forming the titanium oxide nanotube by anodic oxidation includes anodizing the membrane body by immersing the membrane main body in an electrolyte containing fluoride (F < ^- >) ions and the electrolyte containing fluoride ions, Salts containing ions; (HF), sodium fluoride (NaF), and ammonium fluoride (NH ₄ F) in the presence of at least one solvent selected from the group consisting of an inorganic acid, an organic acid, and a high molecular alcohol. And the solvent includes at least one of phosphoric acid (H ₃ PO ₄ ), sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), glycerol, and ethylene glycol .

Preferably, the recess has a hemispherical shape, the diameter is between 10 and 1,000 nm, or the hemispherical recess further comprises micropores of a few nanometers in size on the surface.

The removal of the titanium oxide nanotubes is preferably performed by immersing the membrane main body in aqueous hydrogen peroxide (H ₂ O ₂ ) and ultrasonically cleaning the membrane main body, or removing the titanium oxide nanotubes by immersing them in an aqueous solution of an organic acid or a base.

The object of the present invention is to provide a membrane for an implant, which is characterized in that a membrane body made of a titanium metal or a titanium alloy is anodized to form titanium oxide nanotubes, and the titanium oxide nanotubes are removed to form a groove on the surface of the membrane body. .

In this case, the membrane main body is provided with a groove only on the inner wall surface, and the groove has a semi-spherical shape. The groove has a diameter: height ratio of 1: 0.01 to 0.5, Preferably has a size of 10 to 1,000 nm.

The groove may further include fine pores having a size of several nanometers, and the membrane body may further include an oxide layer having a thickness of 10 to 1,000 nm.

The above-mentioned object is also achieved by a membrane for an implant characterized by comprising a membrane body having a hemispherical recess formed on its surface.

Here, it is preferable that the membrane main body has grooves only on the inner wall surface.

According to the above-described constitution of the present invention, it is possible to obtain an implant membrane having an inner wall surface region having a rough surface and an outer wall surface region having a smooth surface.

Also, the anodized surface of the membrane body is anodized and then the anodized surface is removed to form a groove on the surface. The anodized titanium oxide nanotubes are peeled off and prevented from flowing out from the inside of the living body. At the same time, It is possible to remove impurities.

In addition, biodegradable titanium or titanium alloys can be used as the material of the membrane body and have excellent biocompatibility, chemical compatibility, and mechanical compatibility when implanted into living bodies by grooves formed through surface anodization.

1 and 2 are flowcharts of a method for manufacturing a membrane for an implant according to an embodiment of the present invention,
FIGS. 3 and 4 are SEM images of the anodized metal oxide film according to the prior art,
5 is a SEM photograph showing a membrane main body before anodization,
6 is a SEM photograph showing the formation of the titanium oxide nanotube according to the embodiment,
FIGS. 7 and 8 are SEM images showing recesses and micropores formed on the surface of the membrane body from which the titanium oxide nanotubes are removed,
9 is a graph showing the XPS surface component analysis results of the membrane main body before and after the anodizing step,
10 is an AFM photograph of the surface of the membrane body from which titanium oxide nanotubes have been removed.

Hereinafter, a membrane for an implant having a nano patterning groove surface according to an embodiment of the present invention and a method of manufacturing the same will be described in detail with reference to the drawings.

As shown in the flow charts shown in FIGS. 1 and 2, a polymer protective layer 200 is formed on the outer wall surface of the membrane main body 100 (S1).

The membrane body 100 is made of titanium or a titanium alloy. Since the titanium or titanium alloy is a metal suitable as a bio-implantable material, the membrane body 100 of the present invention is made of titanium or a titanium alloy use. Here, the membrane main body 100 has a mesh shape and has a structure in which a plurality of holes are formed in a plate-shaped titanium or titanium alloy. At this time, the plate shape is preferably bent in a shape similar to the alveolar bone so that the teeth can be lifted onto the alveolar bone and the bone graft material. Also, the holes are formed in a number of tens to hundreds, such that the fixing is advantageous when the membrane is placed on the bone graft material.

The implant membrane should have an inner wall surface that has a high affinity with the living body while providing space and time for bone regeneration. The outer wall surface should have a smooth surface for penetration of epithelial cells, adhesion of foreign substances, . However, these membranes are not very suitable for use in a sand blasting method, which is often used as a surface treatment method of a bio-implantable metal such as an implant, since it is made very thin in order to improve workability during a procedure. In addition, a suitable method for selective surface treatment of the membrane is needed because it is not easy to selectively treat only one of the walls.

The polymer protective layer 200 is first formed on the outer wall surface of the membrane body 100 so as to prevent the outer wall surface of the membrane body 100 from being anodized during the anodic oxidation in order to smooth the outer surface of the membrane . In some cases, the polymer protective layer 200 may be selectively formed only on a part of the outer surface of the membrane body 100 that is not desired to be anodized. In this case, only the area where the polymer protective layer 200 is formed A rough surface is formed and a rough surface is formed in a region where the polymer protective layer 200 is not formed.

The polymer protective layer 200 may be formed of a material such as PDMS (Polydimethylsiloxane), PMMA (Polymethylmethacrylate), PI (Polyimide), PET (polyethylene terephthalate), PES (Polyurethane), polyamide (PA), fiber reinforced plastic (FRP), and mixtures thereof.

The membrane body 100 is anodized to form titanium oxide nanotubes 300 on the surface (S2).

A titanium oxide nanotube 300 made of titanium oxide (TiO ₂ ) is applied to a region where an electrolyte is in contact with a membrane body 100 having a polymer protective layer 200 formed on its outer wall surface, . The titanium oxide nanotubes 300 are formed in the form of a tube on the inner wall surface of the membrane body 100 where the polymer protective layer 200 is not formed and the interface between the membrane body 100 and the membrane body 100 And the hemisphere-like shape. The size of the area recessed by the tube shape has a diameter of several tens to several hundred nanometers, and this diameter can be controlled by controlling the anodizing condition.

Here, the electrolytic solution is an electrolytic solution containing fluoride (F ^- ) ions, and the membrane main body 100 is immersed in the electrolytic solution to anodize it. The electrolytic solution containing a fluoride ion is preferably a mixture of a salt containing a fluoride ion and a solvent selected from at least one selected from the group consisting of a mineral acid, an organic acid, a high molecular alcohol and a mixture thereof, and water. The fluoride salt containing ions of hydrogen fluoride (HF), sodium fluoride (NaF), ammonium fluoride (NH ₄ F) and a salt composed thereof is mixed with phosphoric acid (H ₃ PO _4), sulfuric acid (H ₂ It is preferable to use a mixture of water and a solvent selected from the group consisting of sulfuric acid (SO ₄ ), nitric acid (HNO ₃ ), glycerol, ethylene glycol and mixtures thereof.

Halide based ions can effectively dissolve metals to create pitting corrosion on the metal. However, it is difficult to form a straight and uniform nanotube structure in the case of other halide systems such as chloride (Cl ^- ) and bromide (Br ^- ) among halide ions. However, when the anodic oxidation is performed in the electrolytic solution containing the fluoride ion, since the titanium oxide nanotube having a uniform size and interval is formed, the electrolytic solution containing the fluoride ion is used in the present invention.

The polymer protective layer 200 on the outer wall surface of the membrane body 100 is removed (S3).

After the anodic oxidation is completed on the inner wall surface of the membrane body 100, the polymer protective layer 200 protecting the outer wall surface is removed to prevent anodic oxidation. The polymer protective layer 200 can be simply removed using a cleaning solution such as acetone or the like. The step of removing the polymer protective layer 200 may be removed immediately after the anodic oxidation, but may be removed after the membrane is finally manufactured. That is, this step may be performed at any stage after the anodic oxidation is completed.

The titanium oxide nanotubes 300 are removed to form hemispherical grooves 110 on the surface of the membrane main body 100 (S4).

The titanium oxide nanotubes 300 formed by the anodic oxidation are easily peeled off when a membrane formed of titanium or a titanium alloy is implanted or when a physical force is applied to the implanted membrane, as shown in FIGS. 3 and 4. FIGS. 3 and 4 show anodic oxidation of the metal surface through a general anodic oxidation method as in the prior art, and it can be seen that the metal oxide film is immediately separated even if a slight external force is applied. Therefore, when a membrane manufactured through such a conventional technique is implanted, the metal oxide film is peeled off, and the peeled metal oxide film causes problems such as necrosis of somatic cells and reduction of osseointegration of the membrane. In addition, when the nano-sized micropores are formed through the anodic oxidation, it is difficult to effectively remove the impurities remaining in the oxide film. In order to solve this problem, the titanium oxide nanotubes 300 formed on the membrane body 100 are removed.

The hemispherical grooves 110 are formed on the inner wall surface of the membrane main body 100 by removing the titanium oxide nanotubes 300 formed on the inner wall surface of the membrane main body 100 by a physical method or a chemical method. Even when the titanium oxide nanotubes 300 are removed from the membrane body 100, hemispherical grooves 110 formed by the titanium oxide nanotubes 300 remain on the inner wall surface of the membrane body 100. The physical method is preferably a method in which the titanium oxide nanotubes 300 are dipped in hydrogen peroxide water (H ₂ O ₂ ) to perform ultrasonic cleaning. The chemical method is to immerse the membrane main body 100 in an organic acid or base aqueous solution, A method of causing the tube 300 to fall off is preferable, but the present invention is not limited to these methods.

When the titanium oxide nanotubes 300 formed on the inner wall surface of the membrane body 100 are removed, a nano-sized recess 110 having a substantially hemispheric shape is formed on the inner wall surface of the membrane main body 100, A membrane body 100 having micropores (pores) 111 having a size of several nanometers and a size relatively smaller than that of hemispherical grooves 110 can be obtained in the groove 110. The hemispherical grooves 110 may be formed to have a diameter (d) of 10 to 1,000 nm. This can be achieved by adjusting electrochemical conditions such as an applied voltage, an electrolyte solution, and a temperature at the time of anodic oxidation.

(D): height (h) = 1: 0.01 to 0.5 so that the groove (110) can be formed in a hemispherical shape when the diameter (d) and height (h) When the height h of the groove 110 is less than 0.01 times the diameter d, the height is very low, so that the surface roughness is low and it is not easy to support the formed bone and the soft tissue. The groove 110 is hemispherical It can not exceed 0.5 times. Therefore, the ratio of diameter (d): height (h) = 1: 0.01 to 0.5 is most preferable.

The surface of the membrane obtained through steps S1 to S4 is passivated from a metal to a metal oxide and can be used immediately. When a membrane is manufactured by a conventional technique, the process of immobilizing titanium in a form of titanium oxide which is suitable for a biomaterial and can prevent oxidation is separately performed. Passivation in the form of titanium oxide was carried out by exposing the membrane to high temperature or boiling in hot water. However, in the present invention, the groove 110 may be formed on the surface while passivating the membrane in the form of titanium oxide through the anodic oxidation process.

If necessary, the following steps can be further carried out.

An oxide film 400 is formed on the surface of the membrane main body 100 (S5).

An oxide film 400 is formed on the surface of the membrane main body 100 by heat treating the membrane main body 100 having a smooth shape on the outer wall surface and a groove 110 formed on the inner wall surface. Here, the oxide film 400 may be formed of an oxide film 400 including an oxide groove 410 and an oxide micropores 411 formed along the groove 110 and the micropores 111 of the membrane body 100, And the oxide film 400 formed thereon. If the thickness of the oxide film 400 is less than 10 nm, it is not meaningful to perform the heat treatment separately. If the thickness of the oxide film 400 is more than 1,000 nm, the oxide film 400 may be damaged by an external force And can be separated from the main body 100.

The oxide film 400 is amorphous when the surface of the membrane body 100 on which the grooves 110 are formed is not heat-treated, and becomes a crystalline surface when heat-treated. By changing to the crystalline surface in this way, physicochemical properties such as hydrophilicity, hardness, strength, and thickness of the oxide film can be controlled. The semi-spherical oxide groove 410 including the oxidized micropores 411 is formed in the oxide film 400. The heat treatment temperature for forming the oxide groove 410 is preferably 200 to 1200 DEG C, A crystalline oxide film 400 is formed. When the heat treatment temperature is lower than 200 ° C, an amorphous oxide film 400 is formed. When the heat treatment temperature is higher than 1200 ° C, the membrane body 100 may be deformed.

The semi-spherical oxidation groove 410 formed in the oxide film 400 preferably has a diameter of 10 to 1,000 nm. When the diameter of the oxide groove 410 is less than 10 nm, the coupling strength between the resultant bone and the soft tissue is not high, and the oxide groove 410 having a diameter of more than 1,000 nm can be effectively formed by a chemical or physical method. The diameter of the oxide groove 410 can be controlled through condition control of anodic oxidation. Also, the surface of the oxide groove 410 is formed with a coarse surface having fine oxide fine pores 411 having a size of several nanometers. Through the heat treatment process, the hardness is higher and the crystalline titanium oxide film 400 having a thickness of 10 nm or more, which is relatively thicker than the amorphous titanium oxide film, is formed, so that the biocompatibility and hydrophilicity can be increased.

In the case of titanium (Ti), an amorphous titanium oxide (TiO ₂ ) thin film is formed on the surface as a native oxide layer formed naturally after the titanium oxide nanotubes 300 are removed through anodic oxidation . When heat treatment is performed at 200 to 1200 ° C., an anatase crystal phase is formed at a temperature of about 200 ° C. or more, and a rutile crystalline oxide film is formed at a temperature of 700 ° C. or more. The hardness is rutile>anatase> amorphous in order, and the thickness of the oxide film 400 can be increased to 10 nm or more by heat treatment. That is, as the heat treatment is performed, the hardness of the metal surface on which the hemispherical oxidation groove 410 is formed can be increased and the thickness of the oxide film 400 suitable for a living body can be increased.

Hereinafter, embodiments of the present invention will be described in more detail.

<Examples>

The membrane main body of Fig. 5 made of titanium (Ti) metal having a membrane shape is immersed in ethanol and acetone in an ultrasonic washing machine in order, followed by washing for 2 minutes. After cleaning, the membrane body is dried and then polymethylsiloxane (PDMS) is coated on the outer wall surface of the membrane body where anodic oxidation is not desired. The electrode surface is then spot-welded to the titanium metal to anodize the inner wall surface of the membrane body. Then, the membrane main body, which is an object of anodic oxidation, and platinum (Pt) metal as a counter electrode are immersed in the electrolytic solution. Here, an electrolyte having a composition in which 0.01 to 10 wt% NH ₄ F and 1 to 50 vol% H ₂ O are added to ethylene glycol is used, and the temperature of the electrolytic solution is maintained at room temperature.

When the direct current voltage is applied to both ends of the membrane body as an anode and insoluble platinum metal as a cathode, the inner wall surface of the membrane body is anodically oxidized with titanium oxide (TiO ₂ ). At this time, a DC voltage is applied at a constant voltage of 10 to 200 V for 10 to 300 minutes, and the titanium oxide nanoparticles having a thickness of several microns or more on the inner wall surface of the membrane body are anodized titanium oxide nanotubes .

After the anodic oxidation, the PDMS coated on the outer wall surface is removed using acetone. The PDMS coated surface is not anodized and the smooth surface remains intact. Next, the titanium oxide nanotubes obtained through the anodic oxidation are removed from the membrane body, and the anodized titanium nanotubes are immersed in a 30 wt% hydrogen peroxide (H ₂ O ₂ ) solution for 10 minutes under an ultrasonic washing machine. The titanium oxide nanotubes formed on the inner wall surface of the membrane body are removed through such a method, and grooves are formed on the inner wall surface as shown in FIGS. In FIGS. 7 and 8, it can be seen that fine pores are formed in hemispherical grooves. 9 is an XPS result obtained by comparing and analyzing the surface of the original membrane body with the surface removed after forming the titanium oxide nanotubes by anodic oxidation. 10 shows an atomic force microscope (AFM) image of a membrane body from which anodized titanium oxide nanotubes are removed, and it is found that nano-sized recesses are uniformly formed.

The titanium oxide nanotubes are removed and the titanium membrane body having the recesses formed thereon is subjected to a heat treatment at 200 to 1200 ° C. to form an oxide film having an oxide groove as a nano-sized groove of about 10 to 1,000 nm. In this embodiment, And a titanium membrane having a thin film having a thickness of about 100 nm is formed by heat treatment at a temperature baking furnace.

Such an implant membrane can prevent the surface of the membrane body 100 from being anodized, and then the anodized surface is removed. Thus, the anodized surface is peeled off to prevent the decay of somatic cell necrosis or osseointegration. In addition, when a membrane having hemispherical grooves 110 formed through surface anodization of the membrane body 100 is implanted, the surface area is maximized and the surface roughness is increased, thereby enhancing the biocompatibility and preventing tissue necrosis on the metal surface It has an advantage of preventing the membrane from being separated during the transplantation period because the binding force with the generated bone is increased.

100: membrane body
110: groove
111: Microstructure
200: polymer protective layer
300: Titanium oxide nanotubes
400: oxide film
410: oxidation groove
411: oxidation micropores

Claims (20)

Forming a titanium oxide nanotube by anodizing a membrane body made of a titanium metal (Ti) or a titanium alloy (Ti alloy);
And removing the titanium oxide nanotubes to form grooves on the surface of the membrane body. The method according to claim 1,
Before the step of forming the titanium oxide nanotubes,
Forming a polymeric protective layer to prevent anodic oxidation of the outer wall surface of the membrane body,
After the step of forming the titanium oxide nanotubes,
And removing the polymer protective layer. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 3. The method of claim 2,
The polymer protective layer may be,
Polymers such as PDMS (Polydimethylsiloxane), PMMA (Polymethylmethacrylate), PI (Polyimide), PET (polyethylene terephthalate), PES (Polyethersulfone), PEN (Polyethylene naphthalate), PS (Polystyrene), PU reinforced plastic, and mixtures thereof. &lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
After the step of forming the groove on the surface of the membrane body,
And forming an oxide film having a thickness of 10 to 1,000 nm on the surface of the membrane body by heat treating the membrane body. 5. The method of claim 4,
Wherein the heat treatment is performed at 200 to 1200 占 폚. The method according to claim 1,
The anodic oxidation to form the titanium oxide nanotubes may include:
Wherein the membrane body is immersed in an electrolytic solution containing fluoride (F &lt; ^- &gt;) ions to perform anodic oxidation. The method according to claim 6,
The electrolytic solution containing the fluoride ion,
Salts containing fluoride ions; And at least one solvent selected from the group consisting of inorganic acids, organic acids, and high molecular alcohols. 8. The method of claim 7,
Wherein the salt comprises at least one of hydrogen fluoride (HF), sodium fluoride (NaF), and ammonium fluoride (NH ₄ F). 8. The method of claim 7,
The solvent, acid (H ₃ PO _4), sulfuric acid (H ₂ SO _4), nitric acid (HNO _3), glycerol (glycerol), glycol for the implant, characterized in that it comprises at least one of (ethylene glycol) A method of manufacturing a membrane. The method according to claim 1,
The groove has a semi-spherical shape,
Wherein the membrane has a diameter ranging from 10 to 1,000 nm. The method according to claim 1,
The groove has a semi-spherical shape,
Wherein the hemispherical recess further comprises micropores of a few nanometers in size on the surface. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
Wherein the titanium oxide nanotubes are removed by immersing the membrane main body in hydrogen peroxide water (H ₂ O ₂ ) and ultrasonically washing the membrane bodies. The method according to claim 1,
Wherein the titanium oxide nanotubes are removed by immersing them in an aqueous solution of an organic acid or a base. Wherein the membrane body made of titanium metal or titanium alloy is anodized to form titanium oxide nanotubes, and the titanium oxide nanotubes are removed to form grooves on the surface of the membrane body. 15. The method of claim 14,
Wherein the membrane body has a groove formed only on an inner wall surface thereof. 15. The method of claim 14,
The groove has a semi-spherical shape,
Wherein the groove has a diameter: height ratio of 1: 0.01 to 0.5, and the hemispherical groove has a diameter of 10 to 1,000 nm. 15. The method of claim 14,
Wherein the recess further comprises micropores of a few nanometers in size. &Lt; RTI ID = 0.0 &gt; 21. &lt; / RTI &gt; 15. The method of claim 14,
Wherein the membrane body further comprises an oxide film having a thickness of 10 to 1,000 nm. And a membrane main body having hemispherical grooves formed on the surface thereof. 20. The method of claim 19,
Wherein the membrane body has a groove formed only on an inner wall surface thereof.

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