WO2013131481A1

WO2013131481A1 - Porous hydroxyapatite bioceramic and preparing method thereof

Info

Publication number: WO2013131481A1
Application number: PCT/CN2013/072262
Authority: WO
Inventors: 周科朝; 黄智�; 张斗; 李志友; 张妍; 陈良建
Original assignee: 中南大学
Priority date: 2012-03-07
Filing date: 2013-03-06
Publication date: 2013-09-12
Also published as: CN104220102A; CN102641523A; CN104220102B

Abstract

Disclosed are a porous hydroxyapatite bioceramic and a preparing method thereof. The porous hydroxyapatite bioceramics of the present invention has suitable pore diameters and distribution, porosity, pore-through situations, and pore surface morphology for bone tissue growth, and not only has large pores allowing a new bone to grow into, but also has abundant flake-shaped pores in pore walls, thus transferring osteogenesis. In the preparing method of the present invention, diameters and distribution of polymeric fibers are arranged appropriately in a die in advance, aqueous hydroxyapatite slurry is frozen and solidified by using orientated temperature field to make hydroxyapatite powder particulates to agglomerate and rearrange under of pushing and thrusting of an orientated grown ice crystal, a resulting ice block is frozen and dried to sublime the ice crystal before sintering is performed. The method can perform fine regulating may be performed on the porous microstructure. And porous hydroxyapatite prepared by the present invention has the high pore-through rate and the high porosity, suitable for bone tissue growth.

Description

Porous hydroxyapatite bioceramic and preparation method thereof

Technical field

The invention relates to a porous hydroxyapatite bioceramic and a preparation method thereof.

Background technique

At present, the repair of long bone damage and defects caused by trauma, inflammation, and tumor resection still lacks satisfactory bone substitute materials, which has become a difficult problem to be solved in medicine. At present, the main clinical repair methods for long bone injury are autologous bone graft, allogeneic bone, allogeneic bone graft and artificial bone replacement. Autologous bone transplantation is the "gold standard" for the treatment of bone defects, but it causes damage to the donor tissue when repairing large bone defects. The bone supply is limited, and it is easy to produce complications, and it is often difficult to achieve satisfactory therapeutic effects. Allogeneic bone and allogeneic bone grafts, while avoiding damage to the donor tissue, have a high infection rate and are at risk of causing immune rejection. Therefore, autologous bone and allogeneic bone transplantation have certain limitations in clinical application. Synthetic bone substitute materials have the advantages of easy quality control and standardized mass production while avoiding the above disadvantages, and thus become a focus of biomedical materials research. Porous hydroxyapatite bioceramics are similar to the chemical composition and crystal structure of inorganic substances in human bone, and have good biocompatibility, biodegradability and osteoconductivity, and serve as scaffold materials and artificial bones for bone tissue engineering. There is great potential for application in alternative materials. The porous calcium phosphate bioceramic is implanted into the bone, and the bone can grow into the surface pores and combine by mechanical inlaying. However, the inward growth of bone tissue in hydroxyapatite bioceramics is affected by factors such as the pore size and distribution of the material, porosity, pore penetration and surface morphology of the pores. There are currently no porous hydroxyapatite bioceramic materials that are well suited for bone tissue growth.

technical problem

It is an object of the present invention to provide a plunged porous hydroxyapatite bioceramic suitable for bone tissue.

Technical solution

In order to achieve the above object, the porous hydroxyapatite bioceramic of the present invention has a macroporous and lamellar porous structure, wherein the angle between the lamellar porous and the macroporous channel is -45 to 45, and the macropore pore diameter is 150~1000μm, and the lamellar porous structure pores and the large pore tunnels penetrate each other.

The large holes pass through the entire bioceramic material.

Preferably, the layer-like porous structure has a channel layer spacing of 10 to 50 μm.

Another object of the present invention is to provide a method of preparing a plunged porous hydroxyapatite bioceramic suitable for bone tissue.

In order to achieve the above object, the preparation method of the present invention comprises:

a) will 95-105 parts by weight of deionized water, 0.5-2 parts by weight of polyacrylamide, 0.5-2 parts by weight of polyvinyl alcohol and 5 to 150 parts by weight of hydroxyapatite powder are uniformly mixed to obtain water-based hydroxyapatite Slurry, and aligned with polymer fibers having a diameter of 165~1050μm in the mold;

b) The water-based hydroxyapatite slurry is injected into the mold, and then subjected to low-temperature directional solidification in the same direction as the arrangement of the polymer fibers, and the cooling rate is controlled to 0.5 to 5 ° C / min, and then the frozen body is freeze-dried;

c) Sintering the lyophilized body at 1250 ° C ~ 1350 ° C.

After c-sintering, a porous hydroxyapatite ceramic with a pore diameter of 150-1000 μm and a lamellar porous structure can be obtained, and the angle between the lamellar porous and the macroporous channel is -45° to 45°. And the lamellar porous structure pores and the large pore tunnels penetrate each other.

The low-temperature directional solidification in which the polymer fibers are aligned in the same direction is controlled by different freezing temperatures at both ends of the mold, so that there is a temperature difference inside the mold, so that the ice crystals can be solidified and grown along the direction of the arrangement of the polymer fibers.

Preferably, the polymer fiber is a hydrophobic polymer fiber.

Further preferably, the hydrophobic polymer fiber is polyester or nylon.

Beneficial effect

The porous hydroxyapatite bioceramic of the present invention has pore size and distribution suitable for bone tissue growth, porosity, pore penetration state and surface morphology of pores, and has not only large pores capable of accommodating new bone growth but also having connectivity The rich layer is porous and thus has the function of conducting osteogenesis. In addition, due to the orientation distribution of the pores, the mechanical properties of the ceramics are anisotropic and have a large compressive strength along the pore direction.

The preparation method of the invention prepares the hydroxyapatite powder particles by using the directional temperature field to freeze-solidify the water-based hydroxyapatite slurry in the mold by pre-arranging the orientation, diameter and distribution density of the polymer fibers in the mold. Aggregation rearrangement is carried out under the push repulsion of directional growth ice crystals, and the obtained ice slab is freeze-dried to sublimate and crystallize the ice crystals, thereby leaving porous hydroxyapatite ceramics with lamellar oriented porous structure characterized by ice as a template. The polymer fiber is thermally cracked and volatilized during the sintering process of the porous hydroxyapatite ceramic, leaving a porous porous layer in the porous hydroxyapatite ceramic, and at the same time, a lamellar porous structure formed during the freezing casting process The internal holes of the ceramic penetrate each other. By controlling the diameter of the polymer fiber, the surface morphology, arrangement density and mode of the polyester fiber, the problems of micro-structural parameters such as pore size, pore morphology and spatial distribution of the porous hydroxyapatite ceramics are solved. Its compressive strength in the direction of the hole is comparable to that of the organism's dense bone. The invention can realize the fine regulation of the porous microstructure, and the porous hydroxyapatite prepared by the invention has high pore penetration rate and high porosity, and is suitable for the growth of bone tissue.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal cross-sectional view of a porous hydroxyapatite ceramic prepared in accordance with the present invention.

Fig. 2 is a porous ceramic obtained by adjusting the arrangement density of polymer fibers to obtain different macroporosity. A: low density; B: medium density; C: high density.

Figure 3 shows porous ceramics having different interlayer spacings by adjusting the weight ratio of water to hydroxyapatite powder; A: water: hydroxyapatite = 3:2; B: water: hydroxyapatite = 2:3.

Figure 4 shows the porosity corresponding to the density of the polymer fibers. None: no macropores; low: low density; middle: medium density; high: high density; wherein ▇ is hydroxyapatite weight content is 40%, ○ is hydroxyapatite weight content is 60%

Embodiments of the invention

The invention will now be further described in conjunction with the embodiments.

Example 1

1) Adding 100 g of deionized water, 1 g of polyacrylamide, 1 g of polyvinyl alcohol and 5 g of hydroxyapatite powder to the ball mill jar, and mixing by ball milling for 20 h, a water-based hydroxyapatite slurry is obtained;

2) Fix the polyester woven mesh with a diameter of 185μm at both ends of the mold, and then pass the polyester wire with a diameter of 165μm through the mesh at both ends. Orienting them within the mold;

3) After injecting the water-based hydroxyapatite slurry into the mold, it is placed in a container filled with liquid nitrogen for low-temperature directional solidification (ie, by controlling the flow rate of liquid nitrogen at both ends of the mold to control the temperature and cooling rate at both ends of the mold to realize ice crystal Directional solidification, the same as below), controlling the cooling rate to 5 ° C / min, and then lyophilizing the frozen body in a freeze dryer;

4) The dried body is sintered at 1350 ° C, and after sintering for 1 h, it is cooled to room temperature with the furnace temperature to obtain a porous hydroxyapatite ceramic having a macroporous pore diameter of 150 μm and having a lamellar oriented porous structure. The pore layer spacing of the lamellar porous structure is 50 μm, the angle between the lamellar porous and the macroporous channels is -45° to 45°, and the lamellar porous structure pores and the macroporous pores penetrate each other.

Example 2

1) 95 g of deionized water, 0.5 g of polyacrylamide, 0.5 g of polyvinyl alcohol and 35 g of hydroxyapatite powder were added to the ball mill jar, and the mixture was ball milled for 30 hours to obtain a water-based hydroxyapatite slurry;

2) Fix the nylon woven mesh with a diameter of 530μm at both ends of the mold, and then pass the nylon fiber with a diameter of 510μm through the mesh at both ends. Orienting them within the mold;

3) After the water-based hydroxyapatite slurry is injected into the mold, it is placed in a container filled with liquid nitrogen for low-temperature directional solidification, and the cooling rate is controlled to be 3 ° C / min, and then the frozen body is freeze-dried in a freeze dryer;

4) The dried body is sintered at 1300 ° C, and after sintering for 1 h, it is cooled to room temperature with the furnace temperature to obtain a porous hydroxyapatite ceramic having a macroporous pore diameter of 500 μm and having a lamellar oriented porous structure. The pore layer spacing of the lamellar porous structure is 10 μm, the angle between the lamellar porous and the macroporous channels is -45° to 45°, and the lamellar porous structure pores and the macroporous pores penetrate each other.

Example 3

1) adding 105 g of deionized water, 2 g of polyacrylamide, 2 g of polyvinyl alcohol and 150 g of hydroxyapatite powder to the ball mill, and mixing by ball milling for 20 h to obtain a water-based hydroxyapatite slurry;

2) Fix the polyester woven mesh with a diameter of 1060μm at both ends of the mold, and then pass the polyester wire with a diameter of 1050μm through the mesh at both ends. Orienting them within the mold;

3) After injecting the water-based hydroxyapatite slurry into the mold, placing it in a container filled with liquid nitrogen for low-temperature directional solidification, controlling the cooling rate to 0.5 ° C / min, and then lyophilizing the frozen body in a freeze dryer ;

4) The dried body is sintered at 1250 ° C, sintered for 1.5 h, and then cooled to room temperature with furnace temperature to obtain a porous hydroxyapatite ceramic having a pore size of 1000 μm and having a lamellar oriented porous structure. The pore layer spacing of the lamellar porous structure is 40 μm, the angle between the lamellar porous and the macroporous channels is -45° to 45°, and the lamellar porous structure pores and the macroporous pores penetrate each other.

Claims

A porous hydroxyapatite bioceramic, characterized in that the bioceramic has a macroporous and lamellar porous structure, wherein the angle between the lamellar porous and the macroporous channel is -45°~45°, The pore size of the macroporous channel is 150 to 1000 μm, and the porous pores of the lamellar pores intersect with the macropores.
A porous hydroxyapatite bioceramic according to claim 1, wherein said lamellar porous structure has a channel layer spacing of 10 to 50 μm.
A porous hydroxyapatite bioceramic according to claim 1 wherein said macropores penetrate the entire bioceramic material.
A method for preparing a porous hydroxyapatite bioceramic, characterized in that the method comprises the following steps:

a) will 95-105 parts by weight of deionized water, 0.5-2 parts by weight of polyacrylamide, 0.5-2 parts by weight of polyvinyl alcohol and 5 to 150 parts by weight of hydroxyapatite powder are uniformly mixed to obtain water-based hydroxyapatite Slurry, and aligned with polymer fibers having a diameter of 165~1050μm in the mold;

b) The water-based hydroxyapatite slurry is injected into the mold, and then subjected to low-temperature directional solidification in the same direction as the arrangement of the polymer fibers, and the cooling rate is controlled to 0.5 to 5 ° C / min, and then the frozen body is freeze-dried;

c) The lyophilized body is sintered at 1250 ° C ~ 1350 ° C.
The preparation method according to claim 4, characterized in that after sintering, a porous hydroxyapatite ceramic having a macroporous pore diameter of 150 to 1000 μm and having a lamellar porous structure, lamellar porous and macroporous pores is obtained. The angle between the angles is -45° to 45°, and the lamellar porous structure holes and the large pore channels are interpenetrated.
A method of producing a porous hydroxyapatite bioceramic according to claim 4, wherein said polymer fiber is a hydrophobic polymer fiber.
The method for preparing a porous hydroxyapatite bioceramic according to claim 6, wherein the hydrophobic polymer fiber is polyester or nylon.