KR20030022594A - Ceramic-polymer composite material for tissue engineering using toothapatite and polymer, its manufacturing method, and its application - Google Patents

Abstract

PURPOSE: Provided is a bioabsorptive ceramic-polymer complex material for tissue engineering with teeth apatite and polymer used which mixes teeth apatite, polymer for tissue engineering and solvent to keep porosity on the surface and section so that it improves humidity absorption rate. CONSTITUTION: The production process of the bioabsorptive ceramic-polymer complex material for tissue engineering with teeth apatite and polymer used comprises the steps of: (i) extracting an inorganic material from teeth of human or animals and crushing them to prepare teeth apatite; (ii) selecting one material from PGA, PLA, PLLA, PLGA, chitosan and PHBV as bioabsorptive polymer; (iii) selecting one solvent from methylene chloride, chloroform, DMSO and week acid; and (iv) mixing 60-90wt% of bioabsorptive polymer and 10-40wt% of teeth apatite under the selected solvent to produce a ceramic-polymer complex material.

Description

[Ceramic-polymer composite material for tissue engineering using toothapatite and polymer, its manufacturing method, and its application}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to dental apatite, which is a bioabsorbable ceramic, and more particularly, to dental apatite using a fine chain powder of an inorganic material obtained from a tooth of a human or an animal as a bone substitute material or a biomaterial.

In addition, the present invention mixes biocompatible polymer and dental apatite to maintain uniform porosity on the surface and cross-section while maintaining excellent porosity, non-toxic and naturally decomposed after a certain time, but tissue that can maintain its shape and physical properties for a long time An engineering ceramic-polymer composite material is disclosed.

The present invention also relates to the use of dental apatite and dental apatite-polymer composites as tissue engineering carriers and bone regeneration materials.

In general, synthetic polymers are very useful materials in the field of tissue engineering, and can be easily synthesized, manufactured in various sizes and shapes, and chemical and physical properties can be adjusted according to the intended use. Theoretically, any biodegradable polymers that release non-toxic degradation products can be used for tissue engineering, and polymers of this type are known to be suitable for preparing a matrix (matrix or scaffold). Synthetic polymers most commonly used in tissue engineering are polyglycolic acid (PGA) and polylactic acid (PLA) and their copolymers, polylactic-glycolic acid (PLGA). However, PGAs and PLGAs break down too quickly and produce many small products, causing inflammatory reactions and cysts, and acidifying surrounding tissues during the breakdown, which is particularly disadvantageous for bone tissue regeneration. have.

One of these polymers, polyhydroxybutylate (PHB) polymer, is synthesized as an energy storage source in many kinds of bacteria and has an acid group attached to one end and a hydroxyl group attached to the other end group. Disadvantages of this polymer have been limited to its use because it is very brittle, thermally decomposed and poor in processability. However, when special additives are added during the cultivation of bacteria, copolymers with hydroxyvaleric acid form a thermoplastic polyester of PHBV (polyhydroxybutyrate-co-hydroxyvalerate) to reduce melting temperature, decrease crystallinity, and modulus of elasticity. The improvement of physical properties such as the increase of the toughness and the increase of toughness are achieved. Such PHBV can be used as artificial biomaterials such as drug delivery systems, sutures and artificial skin.

In addition, teeth are hard tissues with high crystallinity and higher mineral content than bone. The mineral part of the tooth is present as apatite crystals, but phosphate ions are replaced by other ions (for example HPO ₄ ⁻ , OH ⁻ ) or interposed between metal ions such as Na ⁺ or Mg ²⁺ . Therefore, to be more precise, the mineral of tooth should be expressed as the main component of hydroxyapatite and whitelockite structurally different tooth apatite, and biological properties and reactivity different from ceramics such as other bone tissue or synthetic hydroxyapatite Indicates. Such dental apatite is disadvantageous in that it is difficult to form because it is in the form of a material or powder useful as a bone substitute. To overcome these shortcomings, some scholars used a mixture of plaster and ceramics, but this is not suitable for tissue engineering.

In bone tissue engineering, reconstruction of bone defects is one of the most difficult areas, and the method of autogenous transplantation is the best method, but the amount is limited, and it is not a complete method because it makes other secondary defects. And allogenic grafts have not completely solved immunological problems, and synthetic materials are highly susceptible to infection and long-term results have not been reported.

Apart from this, reconstruction by polymer-cell constructs is considered a very promising attempt in tissue engineering. These synthetic polymers are made of carriers to help cells grow and organize. As cells secrete their substrates, the goal of tissue engineering is to break down the polymer and remove it from the body, leaving only complete biological tissue. The conditions for the material used as such a carrier are to maintain high strength for an excessively long period of time or to prevent absorption so quickly to maintain physical properties for a necessary period.

However, there is a need to develop a ceramic that can absorb the bio-absorption.

It is a first object of the present invention to provide a method of extracting dental apatite, which is a bioabsorbable ceramic, from a human or animal tooth, and a method of using the extracted dental apatite as a bone substitute material.

The second object of the present invention is to improve the disadvantage that the ceramic is not absorbed in the living body and the disadvantage that the polymer is hydrophobic, while having both the advantages of the ceramic and the advantages of the polymer while being bioabsorbable and hydrophilic that can be used as a tissue replacement or tissue engineering carrier of the human body The present invention provides a use of a phosphorus ceramic-polymer composite material and a ceramic-polymer composite material as a bone substitute material, a bone regeneration material, and a scaffold for tissue engineering of human organ or tissue regeneration.

The third object of the present invention is to form a bioabsorbable polymer material and easily form the size and shape, while mixing the dental apatite to have hydrophilicity to maintain excellent moisture absorption and high porosity without pretreatment, and to produce a non-toxic ceramic engineering polymer-polymer composite material In providing.

The fourth object of the present invention is to have a high crystallinity while maintaining uniform porosity on the surface and cross-section using dental apatite and polymer polyhydroxybutyrate-co-hydroxyvalerate (PHBV) obtained from the teeth, and decomposes naturally after a certain time To provide a ceramic-polymer composite material for tissue engineering and to use it as a scaffold.

1 and 2 are scanning electron micrographs showing the shape of the surface and the cross section of the PHBV-to-apatite composite material according to the present invention.

3 is a graph showing the water contact angle of the PHBV-cheapatite composite material according to the present invention.

Figure 4 is a photograph for showing the degree of hydrophilicity of the PHBV-chiapatite composite material according to the present invention.

5 is an X-ray diffraction graph of the PHBV-cheapatite composite material according to the present invention.

Figure 6 is a graph measuring the tensile strength of the PHBV-cheapatite composite material according to the present invention.

Figure 7 is a graph measuring the biaxial tensile strength of the PHBV-toothite lime composite material according to the present invention.

The present invention for achieving the above object is characterized in that it is used as a bone substitute material by pulverizing only the mineral extracted from extracted tooth of human or animal.

In addition, the present invention is characterized in that the dental apatite is mixed with the bioabsorbable polymer material in preparing a composite material for tissue engineering.

Preferably, the bioabsorbable polymer material is any one selected from polyglycolic acid (PGA), polylactic acid (PLA), polylactic-glycolic acid (PLGA), PLLA, chitosan and polyhydroxybutyrate-co-hydroxyvalerate (PHBV). It is characterized by that.

Preferably, the dental apatite is characterized by pulverizing the extracted tooth to a size of about 400 ㎛ or less after removing the organic material by removing the blood and tissue residue with a hydrogen peroxide solution and heat treatment at a temperature of about 500 to 1300 ℃.

In addition, the composite material for tissue engineering is characterized in that it is prepared as a ceramic-polymer composite material by mixing the bioabsorbable polymer, dental apatite and solvent.

Preferably, the ceramic-polymer composite material is mixed with the polymer 10 to 30% by weight, the solvent 90 to 70% by weight, the dental apatite is characterized in that 10 to 40% by weight based on the polymer weight.

Preferably, the solvent is any one selected from methylene chloride (methylene chloride), chloroform, dimethyl sulfoxide (DMSO), weak acid (week acid).

Also preferably, the ceramic-polymer composite material is characterized in that the pore-forming resin and sodium chloride (NaCl) sintered at 200 to 300 μm as the eluent carrier are further mixed as 80 to 90% by weight relative to the mixed solution of PHBV-cheapatite. do.

Such apatite, ceramic-polymer composite material is used as a bone substitute material, bone regeneration material and scaffold for tissue engineering (tissue engineering) of human organs or tissue regeneration.

Referring to the present invention in more detail as follows. First, in describing the present invention, one of the bioabsorbable polymers is described as PHBV, but PHBV is not limited to the bioabsorbable polymer.

First, a bioabsorbable polymer, preferably a PHBV polymer (moulded by Aldrich) having a molar weight of 690,000-720,000, and dental apatite (TA) is mixed with a solvent, and then solvent-casting / particulate-leaching. The method produces a polymer-to-apatite (TA) composite.

The bioabsorbable polymer used in the present invention is used 60 to 90% by weight based on the polymer-cheapatite mixed weight. At this time, the PHBV polymer, which is one of the bioabsorbable polymers, is prepared by mixing hydroxybutylate and hydroxy valerate (HV) as thermoplastic polyester, and the content of hydroxy valerate is 12 to 30 mol%.

Dental apatite is also stored at about -72 ° C by treating extracted tooth (human, animal) with hydrogen peroxide solution (hydroperoxide) to completely remove blood and tissue residues. The collected teeth are heat treated at a temperature of 500 to 1300 ° C. for 1 hour to remove all organic matter and leave only minerals. After that, it is pulverized to 400 µm or less, preferably 100 µm or less, and 10 to 50% by weight based on the polymer-cheapatite mixed weight is used.

The solvent of the polymer and the apatite is methylene chloride, chloroform, dimethyl sulfoxide (DMSO), or any one selected from weak acids.

The mixture of the polymer, the dental apatite and the solvent is prepared as a ceramic-polymer composite material by a solvent-casting / particulate-leaching method to which a thermal pressurization process is added.

At this time, sodium chloride (NaCl) sintered to have a diameter of 200 to 300㎛ is mixed 80 to 90% by weight with respect to the mixed solution of the polymer-cheapatite as the pore-forming resin and the eluent carrier, it is mixed uniformly in the mixer.

This invention will be described in more detail based on the following examples.

<Example>

1. Preparation of PHBV-Chiapatite Composites

First, 10-30% by weight of PHBV is added to a solvent such as methylene chloride and dissolved to mix for 1 hour at room temperature to produce a homogeneous polymer solution, and then to 0, 10, 20, 30, 40% by weight of the resulting mixture. Tooth apatite (TA) was added, respectively, to prepare five kinds of PHBV-chiapatite mixtures.

2. Preparation of PHBV-TA (Tooth Apatite) Composite Carrier

The porous pore having a uniform pore size was added to 90% of the total weight of NaCl separated using a mesh to have a size of 200 to 300 μm as a porous agent to the mixture of PHBV, dental apatite and solvent prepared as described above. The carrier was produced. The resulting carrier was poured into a mold made of silicone material and evaporated to dry with 0.2 ml of 0.15 gm / l polymer solution containing 0.27 g of NaCl to a thickness of approximately 2.5 mm and a diameter of 20 mm. After drying, all samples were dried in a vacuum at room temperature for 24 hours to remove the remaining solvent to form a disk. The disk-shaped specimens thus prepared were placed in a frame made of brass filled with NaCl and covered with a top plate. The mold was preheated to a pressure of 20 to 30 MPa and a temperature of 160 ° C. for 1 minute and then pressed for 30 seconds at a pressure of 50 to 60 MPa. After that, a disk-shaped specimen containing excessive NaCl in a brass frame was obtained. The specimen was washed with pure water for 25 hours to completely remove NaCl, thereby preparing a porous PHBV-cheapatite composite carrier.

The porosity, hydrophilicity, crystallinity, strength and toxicity were measured as properties for the PHBV-TA composite carrier thus prepared.

3. Characterization of PHBV-PTA Composite Carrier

1) Surface and porosity measurement

Samples of the prepared PHBV-chiapatite composite carrier were cooled in fractured liquid nitrogen, fractured, encoded with gold, measured under 20 kV using SEM (SN550), and analyzed using a scanning electron microscope to analyze the shape of the surface and the cross section. 1 and FIG. 2. At this time, Figure 1a, 2a is 0% by weight of the dental apatite, 10% by weight 1b, 2b, 20% by weight of Fig. 1c, 2c, 30% by weight, based on the mixed weight of PHBV- tooth apatite, 1E and 2E each contain 40% by weight.

As shown, the pore size was similar to the pore size regardless of the content of TA, the size was about 200 to 250㎛ all are uniformly connected open pores form, the pores are well formed on the outer surface It is.

In addition, the minimum injection pressure is set to 0.5 psi, the maximum injection pressure is set to 27.95 psi, the porosity analysis of the carrier using a mercury-containing porosity meter (Autopore III 9420) to calculate the porosity per volume through the total amount of mercury injected in Table 1 Indicated.

Polymer concentration Composition (wt%) Total porosity area (m ² / g) Density (g / mL) Porosity (%) 10 wt% PHBV / TA: 100/0 0.26 0.13 84.07 ± 2.35 10 wt% PHBV / TA: 90/10 0.29 0.16 85.37 ± 1.65 10 wt% PHBV / TA: 80/20 0.24 0.19 84.04 ± 3.23 10 wt% PHBV / TA: 70/30 0.20 0.21 83.49 ± 2.61 10 wt% PHBV / TA: 60/40 0.19 0.25 81.18 ± 3.12

As shown in the figure, the density increased with increasing TA content, and the porosity decreased slightly, but maintained a high porosity of 80 to 88% as a whole.

2) Hydrophilicity Measurement

To compare the degree of hydrophilization according to the content of dental apatite at 0, 10, 20, 30, and 40% by weight in the PHBV-to-apatite composite carrier, a drop of water was applied to the specimen of the PHBV-to-apatite composite carrier, followed by a goniometer-microscope. Water contact angle was analyzed. As a result, as shown in FIG. 3, the water contact angle gradually decreased as the content of dental apatite increased.

In addition, in order to evaluate the degree of hydrophilicity of the carrier, an aqueous ink was deposited on a PHBV-chiapatite carrier containing 40% by weight of dental apatite, and then its absorption was measured. At this time, a PLLA carrier and a PHBV carrier were used as controls. As a result, as shown in Figure 4, the PLLA carrier used as a control was not able to absorb the aqueous ink at all, PHBV-chiapatite composite carrier showed a higher water absorption than the PHBV carrier.

3) Crystallinity Measurement

X-ray diffraction analysis was performed to evaluate the effect of dental apatite on PHBV polymer. X-ray diffraction analysis was performed on a composite carrier mixed with 0, 10, 20, 30 and 40 wt% of dental apatite. As a result, as shown in FIG. 5, the crystallinity of PHBV decreased as the content of dental apatite increased.

4) strength measurement

Each PHBV-chiapatite composite carrier was fabricated into a specimen of 3.18 × 9.53 × 3.2mm conforming to the ASTM standard (D638-90, type V) by a pressure injection method. At this time, in order to minimize the decrease in molecular weight, dental apatite was performed to set a mold temperature of about 170 ° C. and a container temperature of about 100 ° C., and tensile strength was measured using a dynamometer. The change in force versus elongation measured according to ASTM standard at span length 13.5mm cross-head speed 1mm / min is shown in FIG. 6, Young's modulus and maximum tension according to the content of dental apatite are As the apatite content increased, the modulus increased and the maximum tension decreased.

In addition, in order to compare the physical properties of the composite carrier itself, a biaxial tensile test machine (UTM tensile test machine, AG-5000G), as shown in Figure 7, the composite containing 30% by weight of ichpatite in the relationship of the load by distance The average tension was increased in the carrier, but decreased in the composite carrier containing 40% by weight.

5) Toxicity Test

L-929 mammalian fibroblasts were cultured in a 60 mm plate. After removing the culture solution, 5ml of 0.7% agarose overlay medium was applied. After the agar solidified, the negative control sample and the experimental group were placed on the prepared culture plates, respectively, and incubated in the incubator for 24 hours at a temperature of 37 ℃. After removing the sample, 3 ml of 0.01% neutral red stained (viTPAl sTPAining) and further incubated for 30 minutes. The culture medium was removed and the toxicity was assessed by measuring the discoloration of the dye around the specimen and the cell morphology under the microscope at the boundary between living and dead cells. As a result, all samples showed 0/0 almost nontoxic cytotoxicity test.

As described above, the ceramic-polymer composite material of the present invention uses the tooth which is the tissue of the human body and is also non-toxic to the living body by using the bio-absorbing polymer, bio-absorbing, maintains the porosity suitable for the tissue engineering carrier, water absorption degree without pretreatment It has excellent physical properties, with the advantages of ceramics and polymers to create precise forms.

In addition, the ceramic-polymer composite material of the present invention is characterized by improving the difference between the porosity of the outer surface and the inner surface, which is a disadvantage of the conventional polymer carriers, that is, the composite material has a uniform porosity outside or inside the material The porosity and size of the porosity can be controlled, and the size and shape of the carrier can be easily made, that is, the physical properties can be easily manufactured, and thus have easy characteristics for the preparation of tissue engineering carriers.

In addition, the ceramic-polymer composite carrier of the present invention can be used as a bone substitute or regeneration material because it uses dental apatite obtained from a tooth which is a part of the human body, and can also be used as a bone regeneration carrier for tissue engineering and minimizes side effects in human tissue. There is an advantage to this.

Claims (11)

Dental apatite, characterized in that the extraction of only the mineral extracted from the extracted tooth of a human or animal and use it as a bone substitute material or biomaterial. The method of claim 1, wherein the tooth apatite is treated with a hydrogen peroxide solution to completely remove blood stains, tissue residues and foreign matter of the surrounding tissue and heat treated at a temperature of about 500 to 1300 ℃ to remove the organic matter and then pulverized Bone substitute or tissue engineering ceramic material, characterized in that. Tissue engineering ceramic-polymer composite material characterized by mixing a bioabsorbable polymer, dental apatite and a solvent. 4. The ceramic-polymer composite material of claim 3, wherein the dental apatite has a size of 400 µm or less. The method of claim 3, wherein the bioabsorbable polymer material is any one selected from polyglycolic acid (PGA), polylactic acid (PLA), PLLA, polylactic-glycolic acid (PLGA), chitosan and PHBV. Ceramic-polymer composite material for tissue engineering. The ceramic-polymer composite material for tissue engineering according to claim 3, wherein the polymer is mixed with 60 to 90% by weight and the dental apatite is 10 to 40% by weight based on the weight of the dental apatite-polymer composite material. The ceramic-polymer composite material of claim 3, wherein the solvent is any one selected from methylene chloride, chloroform, dimethyl sulfoxide (DMSO), and weak acid. The ceramic for tissue engineering according to claim 3, wherein the pore-forming resin and sodium chloride (NaCl) sintered at 200 to 300 µm as the eluent are further mixed as 80 to 90% by weight with respect to the mixed solution of dental apatite-polymer. Polymer composite materials. The ceramic-polymer composite material for tissue engineering according to claim 3 is used to prepare a mixture of a polymer, dental apatite and a solvent by a solvent-casting / particulate-leaching method to which a heat press process is added. Method for producing a ceramic-polymer composite material for tissue engineering, characterized in that. The method of claim 3, wherein the ceramic-polymer composite material according to claim 3 is used as a bone substitute material or bone regeneration material. The method according to claim 3, wherein the ceramic-polymer composite material according to claim 3 is used as a scaffold for tissue engineering of human organs or tissue regeneration.