CN101991877B - Preparation method of a three-phase CaP-glass coating/porous Al2O3 scaffold biocomposite - Google Patents

Abstract

The invention provides a method for preparing a three-phase CaP-glass coating/porous Al ₂ O ₃ scaffold biocomposite material, which belongs to the technical field of biomedical material preparation. A composite coating consisting of HA and _phosphate -based bioglass was applied on porous _Al2O3 scaffolds to obtain a good combination of biological and mechanical properties. HA powder and bioglass powder of different compositions were mixed in different proportions to make a slurry coated on a porous Al ₂ O ₃ support, and heat treated in air at 800°C for 2h. Hydroxyapatite (HA), tricalcium phosphate (TCP) and hydrogen calcium phosphate (DCP) main crystal phases appeared in the coating phase, forming a three-phase CaP-glass coating. This three-phase CaP-glass coating is _dense , uniform, and tightly attached to the porous _Al2O3 scaffold. The bonding strength can reach up to 50MPa, which is more than twice the bonding strength of pure HA coating. Osteoblasts grew well on this porous Al ₂ O ₃ scaffold coated with a three-phase CaP-glass coating, and the cells actively diffused through the coating to the interior of the porous scaffold.

Description

Preparation method of a three-phase CaP-glass coating/porous Al2O3 scaffold biocomposite

technical field

The invention belongs to the technical field of preparation of biomedical materials, and relates to a preparation method of a three-phase CaP-glass coating/porous Al ₂ O ₃ support biocomposite material.

Background technique

Hydroxyapatite (hydroxyapatite, HA) is the main component (60-70%) of the human body's natural bone, and has excellent biological activity and guidance for bone tissue growth. Therefore, it has aroused great interest in bone replacement. Clinical trials have shown that HA has the ability to directly combine with bone and complete osteoconductivity. However, poor mechanical properties, such as strength and fracture toughness, limit its application in hard tissue replacement.

A coating-substrate system, such as ZrO ₂ , Al ₂ O ₃ , Ti and their alloys as the substrate, and HA as the coating, can obtain a good combination of mechanical properties and biological properties. Studies have shown that coating HA coatings on porous Al ₂ O ₃ scaffolds can obtain coatings with a thickness of 20-30 μm, however, the morphology of the coatings is microporous, and the bonding strength is less than 25 MPa. Hard tissue replacement becomes difficult if the bonding force between the coating and the substrate is poor, and the dissolution rate and bioactivity of sintered HA are poor compared with real human bone.

Contents of the invention

The technical problem to be solved by the present invention is to provide a preparation method of a three-phase CaP-glass coating/porous _Al2O3 scaffold biocomposite material, wherein, the three-phase CaP-glass coating is compact, _uniform , and tightly attached to the porous On the Al ₂ O ₃ stent, the bonding strength between the coating and the stent can reach up to 50MPa, which is more than twice the bonding strength of the pure HA coating.

In order to achieve the above object, the present invention also provides a kind of three-phase CaP-glass coating/porous _Al2O3 preparation method of _scaffold biocomposite material, comprising the following steps:

Step 1: Preparation of triple-phase glass: according to the composition formula xCaO·(0.55-x)Na ₂ O·0.45P ₂ O ₅ , where x is 0.1-0.5, weigh P ₂ O ₅ , NaH ₂ PO ₄ and CaCO _3. Sinter at 1100-1250°C for 1 hour to melt;

Step 2: sequentially quenching, grinding and sieving the molten glass obtained in step (1) to obtain glass powder;

Step 3: mixing the glass powder and hydroxyapatite obtained in step (2) in ethanol, and ball milling for 24 hours to obtain a mixed slurry;

Step 4: preparing a porous Al ₂ O ₃ support by dipping method, and then coating the mixed slurry obtained in step (3) on the porous Al ₂ O ₃ support to obtain a composite coating;

Step 5: After the composite coating is dried, heat the porous Al ₂ O ₃ stent to 700°C at a rate of 50°C/min, then to 800°C at a rate of 5°C/min, hold for 2 hours, and then heat at 1°C/min Cool down to room temperature at a rate of min.

The preparation method of the three-phase CaP-glass coating/porous Al ₂ O ₃ scaffold bio-composite material of the present invention has at least the following advantages: the present invention mixes HA powder and bio-glass powder to make a slurry, and then coats it on the porous Al ₂ O ₃ support, heat treatment in air at 800 ℃ for 2h. Hydroxyapatite (HA), tricalcium phosphate (TCP) and hydrogen calcium phosphate (DCP) main crystal phases appeared in the coating phase, forming a three-phase CaP-glass coating. And this three-phase CaP-glass coating is dense, uniform, and tightly attached to the porous _Al2O3 support, and the bonding strength between the coating and the support can reach up to _50MPa , which is twice the bonding strength of the pure HA coating. above.

Description of drawings

Fig. 1 is the XRD patterns of composite coatings prepared by heat treatment at 800°C for 2 hours and with different additions of glass with a CaO content of 30 mol%.

Detailed ways

The preparation method of the three-phase CaP-glass coating/porous _Al2O3 support biocomposite material of the present invention comprises the following steps _:

Example 1

(1) Preparation of triple-phase glass: according to the composition formula xCaO·(0.55-x)Na ₂ O·0.45P ₂ O ₅ , where x is 0.1, weigh P ₂ O ₅ , NaH ₂ PO ₄ and CaCO ₃ , Sinter at 1100°C for 1 hour to melt;

(2) quenching, grinding and sieving the molten glass obtained in step (1) successively to obtain glass powder with a particle size less than 20 μm;

(3) The glass powder obtained in step (2) and hydroxyapatite (hydroxyapatite, HA) were mixed in ethanol, and ball milled for 24 hours to obtain a mixed slurry, wherein the glass powder accounted for the glass powder and hydroxyapatite 5% of the total mass of stone;

(4) Prepare porous Al ₂ O ₃ support by dipping method, and then apply the mixed slurry obtained in step (3) on the porous Al ₂ O ₃ support by dipping-spinning process, so as to obtain a composite coating;

(5) After the composite coating is dried, the porous Al ₂ O ₃ scaffold is heated to 700°C at a rate of 10°C/min, then heated to 800°C at a rate of 5°C/min, kept for 2 hours, and then heated at a rate of 1°C/min Cool down to room temperature at a rate of min.

Example 2

(1) Preparation of triple-phase glass: according to the composition formula xCaO·(0.55-x)Na ₂ O·0.45P ₂ O ₅ , where x is 0.2, weigh P ₂ O ₅ , NaH ₂ PO ₄ and CaCO ₃ , Sinter at 1250°C for 1 hour to melt;

(2) quenching, grinding and sieving the molten glass obtained in step (1) successively to obtain glass powder with a particle size less than 20 μm;

(3) The glass powder obtained in step (2) and hydroxyapatite (hydroxyapatite, HA) were mixed in ethanol, and ball milled for 24 hours to obtain a mixed slurry, wherein the glass powder accounted for the glass powder and hydroxyapatite 50% of the total mass of stone;

(4) Prepare porous Al ₂ O ₃ support by dipping method, and then apply the mixed slurry obtained in step (3) on the porous Al ₂ O ₃ support by dipping-spinning process, so as to obtain a composite coating;

(5) After the composite coating is dried, the porous Al ₂ O ₃ scaffold is heated to 700°C at a rate of 10°C/min, then heated to 800°C at a rate of 5°C/min, kept for 2 hours, and then heated at a rate of 1°C/min Cool down to room temperature at a rate of min.

Example 3

(1) Preparation of triple-phase glass: according to the composition formula xCaO·(0.55-x)Na ₂ O·0.45P ₂ O ₅ , where x is 0.3, weigh P ₂ O ₅ , NaH ₂ PO ₄ and CaCO ₃ , Sinter at 1150°C for 1 hour to melt;

(2) quenching, grinding and sieving the molten glass obtained in step (1) successively to obtain glass powder with a particle size less than 20 μm;

(3) The glass powder obtained in step (2) and hydroxyapatite (hydroxyapatite, HA) were mixed in ethanol, and ball milled for 24 hours to obtain a mixed slurry, wherein the glass powder accounted for the glass powder and hydroxyapatite 15% of the total mass of stone;

(4) Prepare porous Al ₂ O ₃ support by dipping method, and then apply the mixed slurry obtained in step (3) on the porous Al ₂ O ₃ support by dipping-spinning process, so as to obtain a composite coating;

(5) After the composite coating is dried, the porous Al ₂ O ₃ scaffold is heated to 700°C at a rate of 10°C/min, then heated to 800°C at a rate of 5°C/min, kept for 2 hours, and then heated at a rate of 1°C/min Cool down to room temperature at a rate of min.

Example 4

(1) Preparation of triple-phase glass: according to the composition formula xCaO·(0.55-x)Na ₂ O·0.45P ₂ O ₅ , where x is 0.5, weigh P ₂ O ₅ , NaH ₂ PO ₄ and CaCO ₃ , Sinter at 1200°C for 1 hour to melt;

(2) quenching, grinding and sieving the molten glass obtained in step (1) successively to obtain glass powder with a particle size less than 20 μm;

(3) The glass powder obtained in step (2) and hydroxyapatite (hydroxyapatite, HA) were mixed in ethanol, and ball milled for 24 hours to obtain a mixed slurry, wherein the glass powder accounted for the glass powder and hydroxyapatite 35% of the total mass of stone;

(4) Prepare porous Al ₂ O ₃ support by dipping method, and then apply the mixed slurry obtained in step (3) on the porous Al ₂ O ₃ support by dipping-spinning process, so as to obtain a composite coating;

(5) After the composite coating is dried, the porous Al ₂ O ₃ scaffold is heated to 700°C at a rate of 10°C/min, then heated to 800°C at a rate of 5°C/min, kept for 2 hours, and then heated at a rate of 1°C/min Cool down to room temperature at a rate of min.

Compared with existing products, the present invention has the following advantages:

1) The three-phase CaP-glass coating obtained in the present invention is closely combined with the porous Al ₂ O ₃ support, the pores are uniform, and there is no blocked deformation hole; the thickness of the glass coating coated on the support is about 30 μm, and there is no Delamination and cracks appear, indicating that they are perfectly bonded; while the traditional single HA coating, because it is microporous, cannot see a tight bond with the porous Al ₂ O ₃ scaffold, resulting in a The strength is very low, generally no more than 25MPa;

2) The three-phase CaP-glass coating with a glass addition of 35wt% and a CaO content of less than _30mol % has the highest bonding strength to the porous _Al2O3 scaffold, reaching 50MPa, almost twice that of a single HA coating (less than 25MPa ). Such a large bonding force is due to the addition of glass, the coating is denser, and the combination with the substrate is tighter;

3) Please refer to shown in Fig. 1, HA, TCP, and DCP main crystal phases appear in the phase analysis of the three-phase CaP-glass coating that the present invention obtains, and their chemical composition is very similar, makes three-phase CaP-glass coating The biological activity of the layer is greatly enhanced compared with the single HA coating;

4) The sintering temperature of a single HA coating is relatively high, generally greater than 1200°C, while the melting point of the three-phase CaP-glass coating obtained in the present invention is very low, about 800°C, which greatly reduces the sintering temperature and improves the morphology of the coating ;

5) The present invention has obtained HA, TCP, the change law of the main crystal phase of DCP with the addition amount of glass and the CaO content in the glass, promptly increases CaO content in the glass, the content of HA phase just increases in the three-phase CaP-glass coating ; Increase the amount of glass added, the content of HA phase is decreasing. This allows control of the phase content in the three-phase CaP-glass coating;

6) The present invention has drawn the reason that three main crystal phases appear in the three-phase CaP-glass coating, promptly along with the fusing of glass and slow cooling, crystallization has taken place, has formed glass-ceramic; During the process, TCP and DCP phases are formed; the content of these three phases depends on the composition of the glass;

7) A single glass coating will produce many other calcium phosphorus phases during the firing process, such as Ca(PO ₃ ) ₂ , 4CaO·3P ₂ O ₅ , NaCaPO ₄ , DCP and TCP, but there is no HA phase, biological activity greatly reduced. However, the three-phase CaP-glass coating obtained by the present invention has only DCP, TCP, and HA phases during firing, and these phases all have bioactivity and biocompatibility;

8) A single glass coating is coated on a porous Al ₂ O ₃ support, due to the mismatch of thermal expansion coefficients, severe cracks and delamination have occurred, but the three-phase CaP-glass coating obtained by the present invention is compatible with porous Al ₂ O ₃ brackets combine perfectly.

The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent transformation of the technical solution of the present invention adopted by those of ordinary skill in the art by reading the description of the present invention is the right of the present invention. covered by the requirements.

Claims (1)

1. a kind _of three-phase CaP-glass coating/porous Al ₂ O The preparation method of support biocomposite material, it is characterized in that: comprise the following steps: Step 1: Preparation of triple-phase glass: according to the composition formula xCaO·(0.55-x)Na ₂ O·0.45P ₂ O ₅ , where x is 0.1-0.5, weigh P ₂ O ₅ , NaH ₂ PO ₄ and CaCO _3. Sinter at 1100-1250°C for 1 hour to melt; Step 2: sequentially quenching, grinding and sieving the molten glass obtained in step (1) to obtain glass powder; Step 3: Mix the glass powder and hydroxyapatite obtained in step (2) in ethanol, and ball mill for 24 hours to obtain a mixed slurry, wherein the glass powder accounts for 5% of the total mass of the glass powder and hydroxyapatite ~50%; Step 4: preparing a porous Al ₂ O ₃ support by dipping method, and then coating the mixed slurry obtained in step (3) on the porous Al ₂ O ₃ support to obtain a composite coating; Step 5: After the composite coating is dried, heat the porous Al ₂ O ₃ stent to 700°C at a rate of 50°C/min, then to 800°C at a rate of 5°C/min, hold for 2 hours, and then heat at 1°C/min Cool down to room temperature at a rate of min.

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