KR101016372B1 - Porous guided bone regeneration membrane with selective permeability and bone adhesion property, and preparation method thereof - Google Patents

Abstract

The present invention comprises the steps of preparing a polymer solution; Casting the polymer solution to produce a polymer membrane; And a porous osteoinductive regeneration membrane having asymmetric structure of two or more layers having different average pore sizes prepared through the phase transition by immersing the cast polymer membrane in a non-solvent, and a porous osteoinduction according to the present invention. The regeneration membrane has an asymmetric structure with different pore sizes at the top and the bottom of the membrane to facilitate permeation of nutrients and oxygen essential for bone regeneration, while permeation of fibrous connective tissue, which is an obstacle to bone regeneration, can be suppressed by the pore size. The selective permeability and the porous structure of the surface have excellent adhesion with bone tissue and are very effective for bone regeneration.

 Porous osteoinductive membrane, selective permeability, biocompatible polymer, biodegradable polymer

Description

Porous guided bone regeneration membrane with selective permeability and bone adhesion property, and preparation method

The present invention relates to a porous osteoinductive regeneration membrane having selective permeability and adhesion to bone tissue, and more particularly, to a nutrient solution essential for bone regeneration by making a membrane having an asymmetric structure having different average pore sizes at the top and bottom thereof. The present invention relates to a novel osteoinductive regeneration membrane and a method of manufacturing the same, which can easily permeate oxygen and inhibit the penetration of fibrous connective tissue, which is an obstacle to bone regeneration.

Regeneration of damaged bone tissue occupies a very important place in orthopedic surgery, plastic surgery, dentistry (oral and maxillofacial surgery) and other areas that are closely related to quality of life. In case of damage to bone tissue due to car accidents, fractures, removal of cancerous tissue, surgery for the purpose of plastic surgery, and periodontal disease, the defects are less differentiated epithelial and fibrous connective tissue than highly differentiated bone tissue. It is first filled by HJ to interfere with bone tissue regeneration [JN Kent et al., Otolaryngol. Clin. North. Am ., 17, 273 (1984)]. Treatment that induces regeneration of epithelial and fibrous connective tissues, which play a negative role in bone tissue regeneration, and induces regeneration into desired bone tissue by accessing only defects to cells and substances useful for bone tissue regeneration. It is called guided bone regeneration (GBR), and the membrane used is called a bone induction regeneration membrane (GBR).

The concept of osteoinduction was found in Nyman [S. Nyman, et al., J. Clin. Periodontol ., 9, 257 (1982)] and Gottlow [J. Gottlow, et al., J. Clin. Periodontol. , 11, 494 (1984)], based on the concept of tissue-induced regeneration established by Dahlin [C. Dahlin, et al., Plast. Reconstr. Surg ., 81, 642 (1988)] reported the possibility of bone regeneration using bone guided regeneration membranes and began to establish concretely.Bone guided regeneration was performed by reconstructing bone tissue in vitro and implanting it into the defect. Compared to the histological approach, a lot of researchers are trying to develop a suitable bone guide regeneration membrane.

Materials used as bone-induced regeneration membranes are largely composed of natural polymers such as collagen, alginate, and the like; It can be divided into synthetic polymers such as expanded-polytetrafluoro ethylene (ePTFE), polylactic acid (PLA), polyglycolic acid (poly (glycolic acid), PGA), and the like. Natural polymers have weak physical properties and are easily absorbed (absorption) in the body to meet the function as a bone-induced regenerative membrane is still known to solve many problems, from the study using the biocompatible synthetic polymers ePTFE bone Positive results have been reported for regeneration, but they do not dissolve in the body, and after bone regeneration, they have to be removed through secondary surgery.

For this reason, researches using biodegradable synthetic polymers have been dominant in recent years. Such bone guide regeneration membrane should satisfy the following requirements. 1) It must have biocompatibility first, and 2) have adequate closure to prevent epithelial migration and to prevent infiltration of fibrous connective tissue, and 3) to maintain a space for bone regeneration in bone defects. It should have the mechanical properties of 4) it should be able to adhere well to the surrounding bone tissue to prevent the penetration of fibrous connective tissue from the edge of the membrane, 5) the nutrients and oxygen essential for bone regeneration should be easily permeable, and 6) In order to prevent damage to normal tissues and to give ease of treatment, they must have flexible characteristics.

Recently, due to continuous research on biodegradable polymers, products such as Guidor, Vicryl Periodontal Mesh, and Biomesh based on biodegradable polymers have been released.However, the difficulty of the procedure and bone tissue and It does not meet the most basic requirements for bone-induced regenerative membranes such as low adhesion (fibrinous tissue can penetrate into the membrane), and despite this, the biodegradable polymer does not require reoperation after bone regeneration. The use was very limited.

Moreover, although the permeation of nutrients and oxygen necessary for bone regeneration is possible, there is almost no production of selective permeable membranes having the property of simultaneously inhibiting the penetration of fibrous scar tissue.

Therefore, the present invention does not improve the problems of the prior art as described above, despite a lot of research on bone-induced regenerative membrane for bone regeneration, to solve the problem that still does not produce a satisfactory bone-induced regenerative membrane will be.

In the present invention, by using a phase inversion method to design asymmetrical structure of the pore size of the upper and lower portions of the membrane different from the problem such as control of selective permeation of the conventional bone-induced regeneration membrane and adhesion with bone tissue It became.

Accordingly, it is an object of the present invention to provide a porous osteoinductive regeneration membrane that is imparted with selective permeability and adhesion with bone tissue while permeating nutrient solution and oxygen essential for bone regeneration and inhibiting fibrous connective tissue penetration.

In addition, another object of the present invention to provide a method for producing a porous osteoinductive regeneration membrane having the above characteristics.

The present invention facilitates the penetration of nutrients and oxygen essential for bone regeneration by biocompatible polymers, solvents harmless to the human body, precipitation, washing and drying of the polymer, but inhibits the penetration of fibrous connective tissue, which is an obstacle to bone regeneration. The selective permeability can be excellent and the adhesion with the bone tissue can provide a very positive environment for bone regeneration can be very useful as a new concept bone induction regeneration membrane.

Porous osteoinductive regeneration membrane of the present invention is characterized in that the asymmetric structure including two or more layers of different average pore size.

Method for producing a porous osteoinductive regeneration membrane of the present invention comprises the steps of preparing a polymer solution; Casting the polymer solution to produce a polymer membrane; And immersing the cast polymer membrane in a non-solvent to phase change.

Hereinafter, the present invention will be described in detail.

The present invention comprises the steps of preparing a polymer solution; Casting the polymer solution to produce a polymer membrane; And a phase transition by immersing the cast polymer membrane in a non-solvent, and having a porous structure as a whole, and having an asymmetric structure having a different average pore size at the top and the bottom thereof, passing a material required for bone regeneration. Porous bone oil regeneration membrane with novel structure that can prevent the penetration of tissues unnecessary for bone regeneration.

The porous osteoinductive regeneration membrane having an asymmetric structure of the present invention and a specific method for producing the same will be described in detail below.

First, the biocompatible polymer is dissolved in a suitable solvent to prepare a polymer solution. The biocompatible polymer may be used alone or as a mixture of the biodegradable polymer and hydrophilic polymer.

 Certain biodegradable polymers and hydrophilic polymers used in the present invention are used in the formation of bone-induced regenerative membranes used in the human body, and thus should exhibit biocompatibility.

The biodegradable polymer is a polyester-based polymer having a weight average molecular weight of 1,000 to 1,000,000 g / mol, and specific examples thereof include polylactic acid, polyglycolic acid, and poly. Lactic acid-glycolic acid copolymer (poly (lactic acid-co-glycolic acid)), polydioxanone, polycaprolactone, polylactic acid-caprolactone copolymer (poly (lactic acid-co-co- acid) ε-caprolactone)), polydioxanone-ε-caprolactone (poly (dioxanone-ε-caprolactone)), polyhydroxybutyric acid-co-hydroxyvaleric acid and polyphospho It is one or more selected from the group consisting of ester poly (phosphoester).

In addition, the hydrophilic polymer is a polymer containing a large amount of ethylene oxide (ethylene oxide, -CH ₂ CH ₂ O) or hydroxy (hydroxy, -OH) functional group having a weight average molecular weight of 1,000 to 1,000,000 g / mol, for example , Polyethylene oxide-polypropyleneoxide copolymer (PEO-PPO copolymer, Pluronic series), polyethylene oxide-poly-lactic acid copolymer (PEO-PLA), polyethylene oxide Polylactic glycolic acid copolymer (polyethylene oxide-poly (lactic-co-glycolic acid) (PEO-PLGA), polyethylene oxide-polycaprolactone copolymer (polyethylene oxide-polycaprolactone, PEO-PCL), polyethylene oxide (PEO) ), Polyvinyl alcohol (PVA), polyoxyethylene alkyl ethers (Brij Series), polyoxyethylene castor oil derivatives (Cremophore) s), polyoxyethylene sorbitan fatty acid esters (Tween Series), and polyoxyethylene stearates.

When a biodegradable polymer and a hydrophilic polymer are mixed and used as the biocompatible polymer, the hydrophilic polymer is preferably included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the biodegradable polymer, and the hydrophilic polymer is less than 0.1 part by weight. When used, there is a problem in that the prepared bone induction regeneration membrane does not exhibit hydrophilicity, and when it exceeds 20 parts by weight, no precipitation is formed or physical properties are weakened.

In preparing the biocompatible polymer solution according to the present invention, tetraglycol, 1-methyl-2-pyrrolidinone (1-methyl-2-pyrrolidinone (NMP)), triacetin and benzyl are harmless to humans. It is dissolved in one or more solvents selected from the group consisting of benzyl alcohols.

When dissolved in the solvent, the concentration of the biocompatible polymer solution is preferably 1 to 50% by weight, preferably 10 to 20% by weight, for the preparation of osteoinductive regeneration membrane, and if the polymer solution is less than 1% by weight of the polymer There is a problem that the precipitate is not formed or the physical properties are weak, and when the content exceeds 50% by weight, the solution has a high viscosity, so that it is difficult to dissolve or not handle easily.

In addition to the biodegradable and hydrophilic polymers described above, the present invention may further include biodegradable or hydrophilic polymers while having biocompatibility within the scope of the present invention.

The biocompatible polymer solution may be appropriately changed under conditions maintaining a temperature of room temperature (R.T.) to 100 ° C. according to the polymer used.

After preparing the biocompatible polymer solution as described above, the solution is then taped to a predetermined mold 10 at a predetermined thickness on the four sides of the mold 10 or the general glass substrate 20 as shown in FIG. The polymer film is prepared by applying the solution 40 thereon. In the coating, it is convenient to use a general casting method in the manufacturing process, but is not limited thereto. The thickness of the produced polymer film can be adjusted according to the thickness of the mold used in the casting, preferably 10 to 2,000 ㎛, but is not limited thereto.

Next, the cast polymer film is immersed in a non-solvent to phase inversion. The non-solvent used at this time is at least one selected from the group consisting of water, ethyl alcohol and methyl alcohol, but is not limited thereto. The phase transition time may be performed for 1 minute to 12 hours.

As soon as the polymer membrane cast as described above is immersed in the non-solvent 50, as shown in FIG. 1B, precipitation of the polymer begins to form on the surface 60 where the polymer membrane and the non-solvent meet, and the initial precipitation is formed. Fine pores are formed on the surface, and as the distance from the non-solvent increases, the concentration of the polymer solution decreases to form a pore layer 70 having a larger pore size. That is, the solvent and the non-solvent used in the biocompatible polymer solution are exchanged to form a membrane having a pore layer having a different pore size.

At this time, the upper layer of the polymer membrane has a relatively dense structure having a relatively small average pore size, as shown in FIG. 2, and the lower layer of the polymer membrane has a asymmetric structure having a porous structure having a relatively large average pore size. You can do it. The upper layer of the polymer membrane has an average pore size of 1 to 3,000 nm, more preferably 5 to 100 nm. Having such a pore size, only nutrients and oxygen necessary for the production of bone-induced regeneration membranes can penetrate. And relatively few thousand nm Penetration of large fibrous scar tissue has selective permeability that can be selectively inhibited. Therefore, when the average pore size of the upper layer is less than 1 nm, it is difficult to penetrate the nutrient solution, and when the average pore size exceeds 3,000 nm, the fibrous connective tissue may penetrate, which is not preferable.

In addition, the lower layer of the polymer film has an average pore size of 5 to 500 μm, more preferably 50 to 200 μm, as shown in FIG. 2, and has a relatively large average pore size structure. As the polymer membrane is not brittle and has flexibility, the procedure and adhesion to the bone tissues are easy, and thus the polymer membrane can be very usefully applied as a bone induction regeneration tube.

The bone induction regeneration membrane according to the present invention has a novel asymmetric structure of the dense structure of the upper layer and the porous structure of the lower layer as shown in the cross-section of Figure 2 as follows: It is a act.

In addition, the porous osteoinductive regeneration membrane according to the present invention is preferably in the form of a sheet having a columnar shape as shown in the cross-sectional picture of FIG.

In addition, when hydrophilic (hydrophilic) is imparted to the porous osteoinductive regeneration membrane according to the present invention (membrane made of a mixture of biodegradable / hydrophilic polymer), the penetration of body fluids containing oxygen and nutrients essential for bone regeneration more easily Can be induced.

The polymer film phase-transferred as described above may be prepared through a conventional process such as washing and drying, and this is usually in accordance with known methods and is not particularly limited.

Although this invention is demonstrated in detail based on an Example, this invention is not limited to an Example.

Example 1

Polycaprolactone (weight average molecular weight ~ 80,000 g / mol, polycaprolactone) exhibiting biocompatibility and biodegradability was dissolved in tetraglycol, which is harmless to human body, at 10% by weight, and heated to 90 ° C to prepare a mixed polymer solution.

After the prepared mixed polymer solution was cast in a constant mold (5 x 5 cm; thickness ~ 0.4 mm) stored at room temperature, the mold containing the polymer solution was impregnated with water at room temperature, which is non-solvent. As soon as the polymer solution is in contact with water, precipitation of the polymer begins to form on the surface of the polymer solution. After the first 1 hour of precipitation, the excess solvent is exchanged for 6 hours every hour to replace the residual solvent. Washed thoroughly. After the washing was completed by vacuum drying to obtain a bone-induced regeneration membrane in the form of a sheet.

The surface and the cross-sectional structure of the bone-induced regeneration membrane prepared above were observed through an electron scanning electron microscope (SEM), and the results are shown in FIG. 2. As shown in Figure 2, the bone induction regenerative membrane prepared in Example 1 of the present invention is about 100 nm of the surface (upper layer) in contact with water is possible to penetrate the nutrient solution and oxygen, but not penetrate the fibrous connective tissue It has a porous size, and the cross section of the bone induction regeneration membrane has a columnar porous structure that facilitates permeation of nutrient solution and oxygen, and the lower layer has a porous size of about 100 μm for easy adhesion with bone tissue. Could.

Example 2

Polycaprolactone (weight average molecular weight ~ 80,000 g / mol, polycaprolactone) showing biocompatibility and biodegradability and Pluronic F127 (weight average molecular weight ~ 12,000 g / mol), which is a PEO-PPO copolymer showing biocompatibility, were 1: 0.05 Mixing by weight ratio to dissolve it in 10% by weight, it was heated to 90 ℃ to prepare a mixed polymer solution, which was obtained in the same manner as in Example 1 to obtain a bone-induced regeneration membrane.

As a result of confirming the surface and cross-sectional structure of the bone-induced regeneration membrane prepared using polycaprolactone / Pluronic F127 using SEM, it had a columnar porous structure and showed an asymmetric structure of upper layer ~ 100 nm, lower layer ~ 100 μm. .

Example 3

Polydioxanone (weight average molecular weight ~ 200,000 g / mol, polydioxanone) exhibiting biocompatibility and biodegradability is dissolved in 10% by weight in 1-methyl-2-pyrrolidinone, which is harmless to humans, and mixed by heating to 100 ° C. A polymer solution was prepared, and a bone guide regeneration membrane was obtained in the same manner as in Example 1.

As a result of confirming the surface and the cross-sectional structure of the bone-induced regeneration membrane of the bone-induced regeneration membrane prepared using the polydioxanone using SEM, it has a columnar porous structure and has an asymmetric structure of the upper layer ~ 200 nm, the lower layer ~ 100 ㎛. Indicated.

Example 4

Polydioxanone (weight average molecular weight ~ 200,000 g / mol, polydioxanone) showing biocompatibility and biodegradability, and Pluronic F127 (weight average molecular weight ~ 12,000 g / mol), which is a PEO-PPO copolymer showing biocompatibility, showed a ratio of 1: 0.05. Mix by weight ratio, dissolve it in 10% by weight in 1-methyl-2-pyrrolidinone which is harmless to human body when using a certain amount, and heat it to 100 ℃ to prepare a mixed polymer solution, and the same method as in Example 1 An osteoinductive regeneration membrane was obtained.

The surface and cross-sectional structure of the bone-induced regenerative membrane of the bone-induced regenerative membrane prepared using the polydioxanone / Pluronic F127 was confirmed by SEM, and it had a columnar porous structure, and had an upper layer of 200 nm and a lower layer of 100 μm. Asymmetrical structure was shown.

Experimental Example 1

In order to confirm the bone regeneration effect by the prepared bone-induced regeneration membrane, a rat body (Sprague-Dawley (SD) rat) of 200-250 g body weight was used as a model animal. Tiletamine / zolazepam (10 mg / kg; Zoletil 50, Virbac Laboratories, France) and 2% xylazine hydrochloride (2 mg / kg, Rumpun, Byely Co., Korea) were used for anesthesia in experimental animals. After cutting the skin in the center of the animal's forehead by about 4cm, cut the periosteum and put it aside, while using a 8mm diameter dental punch saw, paying attention to the damage of the blood vessels passing through the meninges and the medial region. 8 mm diameter with critical size defect [JP Schmitz et al., Clin. Orthop. Relat. Res ., 205, 299 (1986)], after forming the bone defects, the bone induction regenerative membrane (φ 12 mm) prepared in Example 1 was covered, and the periosteum and skin were sutured, respectively. At this time, the bone-induced regeneration membrane was well adhered to the bone tissue around the bone defect, so that the membrane could not be lifted. In addition, after inducing bone defects, a control group (blank control) that was closed without any treatment was also tested. After breeding for a certain period of time (8, 16 weeks), bone defects were collected from the sacrificed animals, and histologic examination (H & E staining) was performed to evaluate the bone regeneration effect according to the use of bone regeneration membranes.

As shown in Figure 3, it was observed that Example 1 is superior to bone regeneration compared to the control, when hydrophilized (Example 2), the same pore size as Example 1 (inhibition of penetration of fibrous connective tissue) And hydrophilicity (easily supplying fluids containing oxygen and nutrients to bone defects) was considered to have equal or better bone regeneration ability.

1 is a schematic diagram showing a process for producing bone-induced regeneration membrane according to the present invention,

2 is an electron scanning micrograph of the bone induction regeneration membrane according to the first embodiment of the present invention,

3 is an H & E tissue photograph showing the degree of bone regeneration obtained through the animal experiment of Experimental Example 1 bone induction regeneration membrane prepared in Example 1 of the present invention.

Claims (13)

Porous osteoinduction membrane having an asymmetric structure comprising two or more layers having different average pore sizes. The porous osteoinductive membrane according to claim 1, wherein the porous osteoinductive membrane has an asymmetric structure including an upper layer having an average pore size of 1 to 3,000 nm and a lower layer having an average pore size of 5 to 500 µm. The porous osteoinductive membrane of claim 1, wherein the porous osteoinductive membrane is made of a biodegradable polymer having a weight average molecular weight of 1,000 to 1,000,000 g / mol. The porous osteoinductive membrane according to claim 1, wherein the porous osteoinductive membrane is composed of a mixture of a biodegradable polymer and a hydrophilic polymer. The method of claim 3 or 4, wherein the biodegradable polymer is polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer, polydioxanone, polycaprolactone, polylactic acid-caprolactone copolymer, poly Porous osteoinduced regeneration membrane, characterized in that at least one selected from the group consisting of dioxanone-caprolactone copolymer, polyhydroxybutyric acid-hydroxyvaleric acid copolymer and polyphosphoester. The method of claim 4, wherein the hydrophilic polymer is polyethylene oxide-polypropylene oxide copolymer, polyethylene oxide-polylactic acid copolymer, polyethylene oxide-polylactic glycolic acid copolymer, polyethylene oxide-polycaprolactone copolymer, polyethylene oxide, Osteoinduced regeneration membrane, characterized in that at least one selected from the group consisting of polyvinyl alcohol, polyoxyethylene alkyl ethers, polyoxyethylene caster oil derivatives, polyoxyethylene sorbitan fatty acid esters and polyoxyethylene stearate . The porous osteoinductive membrane according to claim 4, wherein the hydrophilic polymer is included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the biodegradable polymer. Preparing a polymer solution; Casting the polymer solution to produce a polymer membrane; And Phase transition by immersing the cast polymer film in a non-solvent Method for producing a porous osteoinductive regeneration membrane comprising a. The method of claim 8, wherein the polymer is a biodegradable polymer; Or a biocompatible polymer selected from a mixture of the biodegradable polymer and the hydrophilic polymer. The method of claim 8, wherein the polymer solution manufacturing step and the casting step are carried out at a temperature of room temperature to 100 ℃.  The method of claim 8, wherein the solvent used for preparing the polymer solution is tetraglycol, 1-methyl-2-pyrrolidinone (NMP), triacetin, and benzyl. Method for producing a porous bone-induced regeneration membrane, characterized in that at least one selected from the group consisting of alcohol (benzyl alcohol). The method of claim 8, wherein the concentration of the polymer solution is 1 to 50% by weight. The method of claim 8, wherein the non-solvent is at least one selected from the group consisting of water, ethyl alcohol and methyl alcohol.

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