阅读说明：本技术 一种涂覆生物活性涂层的多孔锌合金骨组织工程支架及其制备方法 (Porous zinc alloy bone tissue engineering scaffold coated with bioactive coating and preparation method thereof ) 是由 陈民芳 孙逢栋 由臣 于 2021-08-25 设计创作，主要内容包括：一种涂覆生物活性涂层的多孔锌合金骨组织工程支架及其制备方法,解决了目前高孔隙率锌合金骨组织工程支架力学强度低、生物活性较差的问题。通过合金熔炼、气压渗流铸造和涂层制备而成,包括：1)筛选出不同粒径的氯化钠颗粒,将其倒入模具,压实并预热；2)向熔化的锌液中加入Li、Ag和Mn中的1-3种；3)将锌合金液倒入装有氯化钠颗粒的模具中,进行气压渗流；4)冷却后洗除氯化钠颗粒,剩余多孔锌合金；5)线切割多孔锌合金,然后进行酸处理；6)处理后的多孔锌合金浸入聚合物(海藻酸钠、果胶、壳聚糖等)溶液中,离心干燥。得到孔隙率高,孔径可调,强度较高,生物活性较好的多孔锌合金骨组织工程支架。(A porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating and a preparation method thereof solve the problems of low mechanical strength and poor bioactivity of the conventional high-porosity zinc alloy bone tissue engineering scaffold. Prepared by alloy smelting, air pressure seepage casting and coating, comprising the following steps: 1) screening sodium chloride particles with different particle sizes, pouring the sodium chloride particles into a mould, compacting and preheating; 2) adding 1-3 of Li, Ag and Mn into the molten zinc liquid; 3) pouring the zinc alloy liquid into a mould filled with sodium chloride particles, and carrying out air pressure seepage; 4) after cooling, washing out sodium chloride particles, and leaving the porous zinc alloy; 5) performing wire cutting on the porous zinc alloy, and then performing acid treatment; 6) and immersing the treated porous zinc alloy into a polymer (sodium alginate, pectin, chitosan and the like) solution, and centrifugally drying. The porous zinc alloy bone tissue engineering scaffold with high porosity, adjustable pore diameter, higher strength and better biological activity is obtained.)

1. A porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating is characterized in that: the zinc alloy used by the bracket is added with one or two or more of Li, Ag and Mn, wherein the mass percentage of the alloy elements is Li0.2-1.4 wt.%, and/or Ag0 wt-0.5 wt.%, and/or Mn0 wt-0.5 wt.%, and the balance is pure zinc; the prepared porous zinc alloy bone tissue engineering scaffold can meet the requirements of different bone tissue parts, the compressive yield strength is within the range of 1MP-60MP, the porosity is within the range of 50% -90%, the pore size is within the range of 100-800 mu m, and both the pore size and the porosity can be adjusted.

2. The porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating according to claim 1, wherein: the surface of the porous zinc alloy bone tissue engineering scaffold is provided with a bioactive coating.

3. A preparation method of the porous zinc alloy bone tissue engineering scaffold coated with the bioactive coating according to claim 1 or 2, is characterized by comprising the following specific preparation method:

1) screening the particle size of sodium chloride particles: the sodium chloride particles pass through 20 meshes, 32 meshes, 48 meshes and 150 meshes respectively to obtain the sodium chloride particles with the particle size ranges of 100-300 mu m, 300-500 mu m and 500-800 mu m respectively; after the screening is finished, drying for 2-8h at 300-500 ℃;

2) respectively putting the sodium chloride particles with different particle sizes into different moulds, preheating, and continuously compacting the sodium chloride particles in the process; the degree of compaction is measured by the mass to volume ratio of the sodium chloride granules;

3) smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection; firstly, weighing metals in a certain proportion according to the content of the alloy elements in the claim 1, then melting the zinc block at 500 ℃, adding other selected alloy elements, and homogenizing for half an hour after the zinc block is melted;

4) and (3) seepage casting: heating the homogenized zinc alloy liquid to 560 ℃, casting the zinc alloy liquid into the mould containing the sodium chloride particles in the step 2) which is preheated to 400 ℃, sealing and pressurizing the mould, so that the zinc alloy liquid completely permeates into the pores of the sodium chloride particles, and controlling the gas pressure to be 0.2-0.5 MP;

5) washing of sodium chloride particles: cooling the zinc alloy containing the sodium chloride particles to room temperature after the casting is finished, putting the zinc alloy into a beaker, continuously performing ultrasonic treatment by using clear water, fully washing the sodium chloride particles in the alloy, and leaving a porous zinc alloy structure;

6) optimizing the pore structure of the porous zinc alloy: cutting the cleaned porous zinc alloy wire into the shape of bone defect, and putting the cut zinc alloy into 0.1-0.5M hydrochloric acid solution for ultrasonic treatment for 2-30min, thereby not only increasing the porosity, but also greatly increasing the roughness of the solid strut part;

7) preparation of polymer solution: weighing one or more of sodium alginate, pectin or chitosan, wherein the total weight is 0.2g-2g, and adding into 100ml of acetic acid water solution, wherein the volume ratio of Vol water: stirring Vol acetic acid respectively at the rotation speed of 200-900r/min for 1-10h until the Vol acetic acid is completely dissolved, wherein the Vol acetic acid is 10:1, 9:1, 8:1, 7:1, 6:1, 5:1 and 4: 1;

8) adhering bioactive polymer on the surface of the porous zinc alloy: pouring the 100ml of polymer solution into a 100ml conical flask, putting the porous zinc alloy subjected to acid treatment in the step 6) into the flask, covering a rubber stopper, vacuumizing, and treating for 1-10min under the negative pressure of 0.03-0.09Mpa to ensure that the porous zinc alloy is completely immersed into the polymer solution;

9) centrifuging out the polymer solution in the porous zinc alloy: putting the porous zinc alloy immersed in the bioactive polymer into a centrifuge, centrifuging for 3-10min at the rotating speed of 1000-10000r/min, so that the polymer solution in the porous zinc alloy can be centrifuged out, and preventing excessive bioactive polymer from sealing the inner holes after drying;

10) and (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying for 5h at the temperature of 60 ℃ to obtain the porous zinc alloy bone tissue engineering scaffold with the bioactive coating on the surface.

4. The preparation method of the porous zinc alloy bone tissue engineering scaffold coated with the bioactive coating according to claim 3, wherein the preparation method comprises the following steps: the shape of the bone defect in the step 6) comprises a strip shape, a square block shape and a cylindrical shape.

5. The preparation method of the porous zinc alloy bone tissue engineering scaffold coated with the bioactive coating according to claim 3, wherein the preparation method comprises the following steps: the preparation of the bioactive coating on the surface of the bone tissue engineering scaffold improves the biocompatibility of the porous zinc alloy scaffold, can well adhere cells and promote the growth of the cells.

Technical Field

The invention relates to a preparation method of a degradable porous zinc alloy bone tissue engineering scaffold, which mainly comprises the preparation of porous zinc alloy (Zn, Li, Ag and Mn) and the preparation of a porous zinc alloy surface bioactive coating, and belongs to the technical field of the design, preparation and application of biomedical materials of bone tissue engineering scaffolds.

Background

The bone tissue engineering scaffold is mainly used for repairing bone defect parts caused by bone tumors, bone inflammation or trauma, and the current research mainly focuses on a plurality of directions of Polymer (PLGA), bioactive glass or ceramic, non-degradable metal (titanium alloy), degradable metal and the like. The bone tissue engineering scaffolds prepared from various materials have advantages and disadvantages. The polymer has low mechanical strength, and the bioactive glass and the ceramic have good bioactivity but high brittleness, and are not suitable for repairing bone defect of a bearing part. When the non-degradable metal is implanted for a long time, harmful ions are dissolved out, so that an implanted part generates an inflammatory reaction. The iron, zinc, magnesium and other degradable metal stents have higher strength, degradability and certain bioactivity, and have great market prospect in the field of bone tissue engineering.

Zinc is one of the major elements of human body, and plays an important role in various physiological functions such as normal growth, immune function, protein and DNA synthesis, wound healing and the like. In order to avoid zinc deficiency, the intake of 15-40 mg of zinc per day is recommended. In vitro studies have shown that zinc promotes osteoblast adhesion, proliferation, differentiation (i.e. stimulates bone formation) and inhibits bone resorption. The electrode potential of zinc is-0.762V, which is between magnesium (-2.372V/SCE) and iron (-0.444V/SCE). The degradation rate of zinc-based alloys of different composition in simulated body fluids is in the range of 20-300 μm/year, lower than fast degrading magnesium-based alloys (typically higher than 300 μm/year), higher than slow degrading iron-based alloys (typically lower than 50 μm/year). Thus, moderate corrosion behavior and excellent mechanical properties provide potential prospects for zinc alloys as tissue engineering scaffolds.

The porous zinc alloy with high porosity and good connectivity can be prepared by seepage casting, and the method is a good method for preparing the porous bone tissue engineering scaffold. Yi et Al prepared porous alloys of Zn-3 wt.% Cu [ Y. Hou, et Al, Synthesis of biodegradable Zn-based coatings using NaCl templates, Relationship between porous properties and degradation detectors, Materials Characterization (2018)137: 162) 169 ], Zhao et Al prepared porous alloys of Zn-1 wt.% Al [ L.ZHao, et Al, mechanical properties and biodegradation of porous Zn-1Al alloys Letters (2019)247:75-78 ], but the alloying elements Cu, Al are non-vital elements, the biocompatibility of which is not ideal. Some studies have shown that the mechanical strength of the scaffold decreases as its porosity increases. The addition of the metal Li can form a structure that LiZn4 and lamellar zinc are alternately arranged in matrix zinc, so that the mechanical property of the zinc alloy can be greatly improved, and the porous zinc alloy bracket with high porosity can keep enough mechanical strength. According to the current research report, the strengthening effect of Li element on zinc alloy is most obvious, and the excellent biocompatibility of Li element can completely meet the requirement of in vivo implantation. The mechanical strength of the zinc alloy is continuously increased along with the increase of the Li content, so that the mechanical strength of the porous zinc alloy bracket can be adjusted by adjusting the content of the Li element. Small amounts of Li (0.2-1.4 wt.%) can greatly enhance the mechanical strength of Zn. The addition of the metal silver and the metal manganese can refine grains and well improve the toughness of the material. Although the zinc-lithium alloy has better mechanical properties, no relevant report is found in the research of preparing the zinc-lithium porous alloy by using seepage casting.

Some studies have shown that zinc alloy scaffolds do not adhere well to cells, increasing the healing time at the site of injury. The bioactive coating is prepared on the surface of the porous zinc alloy bracket, so that the cell activity can be well increased, and the rapid healing of an implanted part is promoted. Jasmin et al prepared a Collagen Coating on a Bioactive Glass scaffold to promote cell proliferation [ Jasmin H, et al, Collagen as Coating Material for 45S5 biological Glass-Based scans for Bone Tissue Engineering, International Journal of molecular Sciences, (2018)6: 1807-. Ana et al have improved biocompatibility by etching porous titanium alloy scaffolds with hydrofluoric acid [ Civantosa, et al, Designing bioactive porous titanium organic properties and in vitro cells biology and technologies, (2019)368: 162-. However, the preparation of coatings on porous zinc alloy stents has not been much investigated. Anhao characteristic and the like, a layer of antibacterial ZnO coating is prepared on the porous zinc alloy by a hydrothermal method, (2021)2: 58-65) of research and surface technology of ZnO surface modification Zn-Cu tissue engineering scaffold, but the prepared coating has a certain non-uniform phenomenon due to large difference of internal and external pH values of the porous zinc, and the bioactivity and biocompatibility of the zinc alloy scaffold are not improved.

Disclosure of Invention

The invention aims to solve the dual problems of insufficient mechanical property and poor bioactivity of a high-porosity porous zinc alloy bracket, provides a method for combining seepage casting porous zinc alloy with a surface physical adhesion bioactive coating, and prepares a bone tissue engineering bracket with excellent mechanical property and bioactivity for repairing a bone tissue defect part.

In order to meet the requirements of different implantation parts on the mechanical properties of the zinc alloy stent, the lithium element is added into the zinc alloy subjected to seepage casting for the first time, so that the mechanical strength of the stent is greatly improved, and the Ag and Mn elements are added on the basis of the zinc-lithium alloy, so that the toughness of the stent material is improved. And coating a layer of bioactive coating (sodium alginate, pectin and chitosan) on the surface of the porous zinc alloy to obtain the porous zinc alloy scaffold with good bioactivity and compatibility.

Technical scheme of the invention

A zinc alloy bone tissue engineering scaffold coated with a bioactive coating is characterized in that an alloy element added in a zinc alloy material of the tissue engineering scaffold is one or two or more of Li, Ag and Mn, and the weight percentages of the components are respectively as follows: 0.2-1.4 wt.% for Li, 0-0.5 wt.% for Ag, and/or 0-0.5 wt.% for Mn, the remainder being Zn. The porous zinc alloy bone tissue engineering scaffold prepared by adopting the air pressure seepage method can meet the requirements of different bone tissue parts, the compressive yield strength is within the range of 1MP-60MP, the porous zinc alloy bone tissue engineering scaffold has mutually communicated pores, the pore size is 100-800 mu m, the porosity is 50% -90%, and the pore size and the porosity can be adjusted. The surface of the porous zinc alloy stent is provided with a bioactive coating.

A preparation method of a porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating comprises the following steps:

1) screening the particle size of sodium chloride particles: the sodium chloride particles pass through 20 meshes, 32 meshes, 48 meshes and 150 meshes respectively, so as to obtain the sodium chloride particles with the particle size ranges of 100-300 mu m, 300-500 mu m and 500-800 mu m respectively. After the screening is finished, drying treatment is carried out for 2-8h at the temperature of 300-500 ℃.

2) And respectively putting the sodium chloride particles with different particle sizes into different moulds, preheating, and continuously compacting the sodium chloride particles in the process. The degree of compaction can be measured by the mass to volume ratio of the sodium chloride granules.

3) Smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection. Firstly, metals (Zn, Li (0.2-1.4 wt.%), Ag (0-0.5 wt.%), Mn (0-0.5 wt.%)) in a certain ratio are weighed according to the content of the alloy elements in the porous zinc alloy bone tissue engineering scaffold. The zinc mass is then melted at 500 ℃, and one or more of the other selected alloying elements (Li, Ag, Mn) are added, homogenized for half an hour after it has melted.

4) And (3) seepage casting: heating the homogenized zinc alloy melt to 560 ℃, casting the zinc alloy melt into the mould containing the sodium chloride particles in the step 2) which is preheated to 400 ℃, and sealing and pressurizing the mould to ensure that the zinc alloy melt completely permeates into the pores of the sodium chloride particles. The gas pressure is generally controlled to be 0.2-0.5 MP.

5) Washing of sodium chloride particles: and (3) putting the zinc alloy and the sodium chloride particle block body cooled to room temperature into a beaker, continuously performing ultrasonic treatment by using clear water, and fully washing away the sodium chloride particles in the alloy to leave the porous zinc alloy.

6) Optimizing the pore structure of the porous zinc alloy: cutting the cleaned porous zinc alloy wire into bone defect shapes including strip, square and cylinder shapes; such as a wafer having a diameter of 6-8mm and a height of 2-3mm, and then immersed in a 0.1-0.5M hydrochloric acid solution for sonication for 2-30min to increase the zinc alloy porosity and roughness of the zinc alloy solid strut surface.

7) Preparation of polymer solution: one or more of sodium alginate, pectin, chitosan and the like are weighed, the total weight is 0.2g-2g, the mixture is added into 100ml of aqueous solution of acetic acid (Vol water: Vol acetic acid is 10:1, 9:1, 8:1, 7:1, 6:1, 5:1 and 4:1), and the mixture is stirred for 1-10h at the rotating speed of 200r/min-900r/min until the mixture is completely dissolved.

8) Adhering bioactive polymer on the surface of the porous zinc alloy: pouring the 100ml of polymer solution into a 100ml conical flask, putting the porous zinc alloy subjected to acid treatment in the step 6) into the conical flask, covering a rubber stopper and vacuumizing. Treating under 0.03-0.09Mpa for 1-10min to make the porous zinc alloy completely immersed in the polymer solution.

9) Centrifuging out the polymer solution in the porous zinc alloy: and (3) putting the porous zinc alloy immersed in the bioactive polymer into a centrifuge, centrifuging for 3-10min at the rotating speed of 1000-10000r/min to enable the polymer solution in the porous zinc alloy to be centrifuged out, and preventing excessive bioactive polymer from blocking the inner holes after drying.

10) And (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying for 5h at the temperature of 60 ℃ to obtain the porous zinc alloy bone tissue engineering scaffold with the bioactive coating on the surface.

The invention has the advantages and beneficial effects that:

the porous zinc alloy stent with adjustable strength and excellent bioactivity is prepared by casting the porous zinc alloy stent through seepage and combining with bioactive coatings (a sodium alginate coating, a pectin coating and a chitosan coating). The prepared porous scaffold has high porosity (50-90%), adjustable pore size (100-800 μm), uniform pore distribution, good pore connectivity and excellent biocompatibility. Under the high porosity state, the compressive yield strength of the zinc alloy stent can be kept within the range of 1MP-60MP by adjusting the content of the additive elements (Li, Ag and Mn) in the zinc alloy stent, so as to meet the requirements of bone defect repair at different parts. A bioactive coating with excellent bioactivity is prepared on the porous zinc alloy bracket, and can well adhere to cells, promote the growth of the cells and accelerate the healing of bone injury parts.

Drawings

FIG. 1 is a flow chart of seepage casting.

Fig. 2 is a macroscopic morphology of the porous zinc alloy.

FIG. 3 is an electron microscope picture of a porous zinc-lithium alloy.

Fig. 4 is an electron microscope picture of the porous zinc-lithium-silver alloy.

Fig. 5 is an electron microscope picture of the acid treated porous zinc alloy.

FIG. 6 is an electron microscope picture of the pectin coating prepared on the porous zinc alloy.

Detailed Description

Example 1:

the embodiment relates to a preparation method of a porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating (pectin coating), wherein the pore size is 100-300 mu m, the porosity is 50-70%, and a zinc-lithium alloy (Zn-0.8 wt.% Li) is used as a matrix. FIG. 3 shows the pore distribution and pore size of the porous zinc alloy, and the porosity of the porous zinc alloy is measured by the drainage method. The specific method comprises the following steps: and putting the cut porous sample (phi 6X 20mm) into a 25ml measuring cylinder filled with 10ml of water, connecting the measuring cylinder to a vacuum machine, and vacuumizing for about 5min until all gas in the porous metal is exhausted. At this point the volume of water drained by the porous scaffold (V) was recorded₂). The volume of the porous sample was the volume (V) of a cylinder (. phi.6X 20mm)₁＝565.2mm³)。

The porosity of the porous sample can be obtained from the formula.

The method comprises the following specific implementation steps:

screening the particle size of sodium chloride particles: the sodium chloride particles pass through 48-mesh and 150-mesh sieves respectively, so that the sodium chloride particles with the particle size range of 100-300 mu m can be obtained. After the screening is finished, drying treatment is carried out for 6 hours at 400 ℃.

300g of sodium chloride granules are placed in a mould of the sizePreheating to 300 ℃ and keeping the temperature for 8 h. And continuously compacting the sodium chloride particles in the process to ensure that the density of the sodium chloride particles reaches 60-70%. Naturally piled sodium chloride salt particles are compacted to the extent of 50% -60%, and we compact the naturally piled sodium chloride salt particles down by 1 cm. The degree of compaction can be measured by the mass to volume ratio of the sodium chloride granules.

Smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection. Firstly, 992g of pure zinc and 8g of lithium sheets are weighed according to the content proportion of Zn-0.8 wt.% Li in the zinc-lithium alloy. The zinc mass is then melted at 500 ℃ and the lithium flakes are added thereto and homogenized for half an hour after melting.

And (3) seepage casting (the casting process is shown in figure 1): and heating the homogenized zinc-lithium alloy liquid to 560 ℃, casting the zinc-lithium alloy liquid into a mould containing sodium chloride particles preheated to 400 ℃, and sealing and pressurizing the mould to ensure that the zinc alloy liquid completely permeates into the pores of the sodium chloride particles. The gas pressure was controlled at 0.5 MP.

Washing of sodium chloride particles: and cooling the zinc alloy containing the sodium chloride particles to room temperature after the casting is finished, putting the zinc alloy into a beaker, continuously performing ultrasonic treatment by using clear water, changing the clear water for 2 hours, and repeating the ultrasonic treatment for 10 times. Fully washing away sodium chloride particles in the zinc alloy, and leaving a porous zinc alloy structure with the pore size of 100-300 mu m. The macro-topography is shown in fig. 2.

Acid treatment: and performing linear cutting on the cleaned porous zinc alloy, and cutting out a wafer with the diameter of 8mm and the height of 3 mm. And (3) putting the cut zinc alloy into 0.1M hydrochloric acid solution for ultrasonic treatment for 30min, taking out the zinc alloy, washing the zinc alloy for three times by using clear water, and drying the zinc alloy. The morphology after treatment is shown in FIG. 4.

Preparing a pectin solution: 2g of pectin are added to 100ml of an aqueous solution of acetic acid (Vol water: Vol acetic acid ═ 10:1) and stirred at 200r/min for 10h until complete dissolution.

Adhering pectin on the surface of the porous zinc alloy: pouring the 100ml pectin solution into a 100ml conical flask, putting the porous zinc alloy after acid treatment into the conical flask, covering a rubber stopper and vacuumizing. Treating under 0.03Mpa for 10min to completely immerse the porous zinc alloy in the pectin solution.

Centrifuging to obtain a pectin solution in the porous zinc alloy: and (3) putting the porous zinc alloy soaked in the pectin into a centrifuge, centrifuging for 3min at the rotating speed of 1000r/min to enable the pectin solution in the porous zinc alloy to be centrifuged out, and preventing excessive pectin from blocking internal holes after drying.

And (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying at 60 ℃ for 5h to obtain the porous zinc alloy bone tissue engineering scaffold with the pectin coating on the surface. The morphology is shown in FIG. 6.

Example 2

The embodiment relates to a preparation method of a porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating (chitosan coating), the pore size is 500-800 μm, the porosity is 70-90%, and zinc-lithium-silver alloy (Zn-0.8 wt.% Li-0.5 wt.% Ag) is used as a matrix. The porosity of the porous zinc alloy was measured by the drainage method, the procedure being the same as in example 1.

The method comprises the following specific implementation steps:

screening the particle size of sodium chloride particles: the sodium chloride granules pass through 20-mesh and 32-mesh sieves respectively to obtain the sodium chloride granules with the particle size range of 500-800 mu m. After the screening is finished, drying treatment is carried out for 2h at 500 ℃.

300g of sodium chloride granules are placed in a mould of the sizePreheating to 400 ℃ and preserving heat. And continuously compacting the sodium chloride particles in the process to ensure that the density of the sodium chloride particles reaches 80-90 percent. Naturally piled sodium chloride salt granules are compacted to a degree of 50% to 60% and we compact 300g of naturally piled sodium chloride salt granules down 2 cm. The degree of compaction can be measured by the mass to volume ratio of the sodium chloride granules.

Smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection. Firstly, 987g of pure zinc, 8g of lithium sheets and 5g of silver particles are weighed according to the content proportion of Zn-0.8 wt.% Li to 0.5 wt.% Ag of the zinc-lithium-silver alloy. Then, the zinc block was melted at 500 ℃, and the lithium pieces and silver particles were added thereto, and homogenized for half an hour after it was melted.

And (3) seepage casting (the casting process is shown in figure 1): and heating the homogenized zinc-lithium-silver alloy liquid to 560 ℃, casting the homogenized zinc-lithium-silver alloy liquid into a mould containing sodium chloride particles, which is preheated to 400 ℃, and sealing and pressurizing the mould to ensure that the zinc alloy liquid completely permeates into the pores of the sodium chloride particles. The gas pressure was controlled at 0.2 MP.

Washing of sodium chloride particles: and cooling the zinc alloy containing the sodium chloride particles to room temperature after the casting is finished, putting the zinc alloy into a beaker, continuously performing ultrasonic treatment by using clear water, changing the clear water for 2 hours, and repeating the ultrasonic treatment for 10 times. Fully washing away sodium chloride particles in the zinc alloy, and leaving a porous zinc alloy structure with the pore size of 500-800 mu m. The morphology is shown in FIG. 5.

And performing linear cutting on the cleaned porous zinc alloy, and cutting out a wafer with the diameter of 6mm and the height of 2 mm. And (3) putting the cut zinc alloy into 0.5M hydrochloric acid solution for ultrasonic treatment for 2min, taking out the zinc alloy, washing the zinc alloy for three times by using clear water, and drying the zinc alloy.

Preparation of chitosan solution: 0.2g of chitosan was added to 100ml of an aqueous solution of acetic acid (Vol water: Vol acetic acid 4:1) and stirred at 900r/min for 1h until it was completely dissolved.

Adhering chitosan on the surface of the porous zinc alloy: pouring the 100ml chitosan solution into a 100ml conical flask, putting the porous zinc alloy after acid treatment into the conical flask, covering a rubber stopper and vacuumizing. Treating under 0.09Mpa for 10min to completely immerse the porous zinc alloy in the chitosan solution.

Centrifuging to obtain a chitosan solution inside the porous zinc alloy: and (3) putting the porous zinc alloy soaked in the chitosan into a centrifugal machine, centrifuging for 10min at the rotating speed of 10000r/min to enable the chitosan solution in the porous zinc alloy to be centrifuged out, and preventing excessive chitosan from blocking internal pores after drying.

And (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying for 5h at the temperature of 60 ℃ to obtain the porous zinc alloy bone tissue engineering scaffold with the chitosan coating on the surface.

Example 3

The embodiment relates to a preparation method of a porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating (sodium alginate coating), wherein the pore size is 500-800 μm, the porosity is 70-90%, and zinc-lithium-manganese alloy (Zn-0.8 wt.% Li-0.5 wt.% Mn) is used as a matrix. The porosity of the porous zinc alloy was measured by the drainage method, the procedure being the same as in example 1.

The method comprises the following specific implementation steps:

screening the particle size of sodium chloride particles: the sodium chloride granules pass through 20-mesh and 32-mesh sieves respectively to obtain the sodium chloride granules with the particle size range of 500-800 mu m. After the screening is finished, drying treatment is carried out for 6 hours at 400 ℃.

300g of sodium chloride granules are placed in a mould of the sizePreheating to 400 ℃ and preserving heat. And continuously compacting the sodium chloride particles in the process to ensure that the density of the sodium chloride particles reaches 80-90 percent. Naturally piled sodium chloride salt granules are compacted to a degree of 50% to 60% and we compact 300g of naturally piled sodium chloride salt granules down 2 cm. The degree of compaction can be measured by the mass to volume ratio of the sodium chloride granules.

Smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection. Firstly, 952g of pure zinc, 8g of lithium sheet and 40g of zinc-manganese intermediate alloy (Zn-20 wt.% Mn) are weighed according to the content ratio of zinc-lithium-manganese alloy Zn-0.8 wt.% Li to 0.5 wt.% Mn. Then, the zinc block is melted at 500 ℃, the lithium sheet and the zinc-manganese intermediate alloy are added, and after the lithium sheet and the zinc-manganese intermediate alloy are melted, the mixture is homogenized for half an hour.

And (3) seepage casting (the casting process is shown in figure 1): and heating the homogenized zinc-lithium alloy liquid to 560 ℃, casting the zinc-lithium alloy liquid into a mould containing sodium chloride particles preheated to 400 ℃, and sealing and pressurizing the mould to ensure that the zinc alloy liquid completely permeates into the pores of the sodium chloride particles. The gas pressure was controlled at 0.5 MP.

Washing of sodium chloride particles: and cooling the zinc alloy containing the sodium chloride particles to room temperature after the casting is finished, putting the zinc alloy into a beaker, continuously performing ultrasonic treatment by using clear water, changing the clear water for 2 hours, and repeating the ultrasonic treatment for 10 times. Fully washing away sodium chloride particles in the zinc alloy, and leaving a porous zinc alloy structure with the pore size of 500-800 mu m.

And performing linear cutting on the cleaned porous zinc alloy, and cutting out a wafer with the diameter of 8mm and the height of 3 mm. And (3) putting the cut zinc alloy into 0.5M hydrochloric acid solution for ultrasonic treatment for 10min, taking out the zinc alloy, washing the zinc alloy for three times by using clear water, and drying the zinc alloy.

Preparation of sodium alginate solution: 2g of sodium alginate are added to 100ml of an aqueous solution of acetic acid (Vol water: Vol acetic acid 4:1) and stirred at 700r/min for 8h until they are completely dissolved.

Adhering sodium alginate on the surface of the porous zinc alloy: pouring the above 100ml sodium alginate solution into a 100ml conical flask, adding the porous zinc alloy after acid treatment, covering with a rubber plug and vacuumizing. Treating under 0.08Mpa for 5min to make the porous zinc alloy completely immersed in sodium alginate solution.

Centrifuging to obtain a sodium alginate solution inside the porous zinc alloy: and (3) putting the porous zinc alloy immersed in the sodium alginate into a centrifuge, centrifuging for 5min at the rotating speed of 7000r/min to enable the sodium alginate solution in the porous zinc alloy to be centrifuged out, and preventing excessive sodium alginate from blocking internal holes after drying.

And (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying for 5h at the temperature of 60 ℃ to obtain the porous zinc alloy bone tissue engineering scaffold with the sodium alginate coating on the surface.

Example 4

The embodiment relates to a preparation method of a porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating (sodium alginate coating), wherein the pore size is 100-300 mu m, the porosity is 50-70%, and zinc-lithium-manganese alloy (Zn-1.4 wt.% Li-0.5 wt.% Mn) is used as a matrix. The porosity of the porous zinc alloy was measured by the drainage method, the procedure being the same as in example 1.

The method comprises the following specific implementation steps:

screening the particle size of sodium chloride particles: the sodium chloride granules are respectively sieved by 48 meshes and 150 meshes to obtain the sodium chloride granules with the particle size range of 100-300 mu m. After the screening is finished, drying treatment is carried out for 6 hours at 400 ℃.

300g of sodium chloride granules are placed in a mould of the sizePreheating to 400 ℃ and preserving heat. And continuously compacting the sodium chloride particles in the process to ensure that the density of the sodium chloride particles reaches 50-70%. Naturally piled sodium chloride salt granules are compacted to a degree of 50% to 60%, and we compacted 300g of naturally piled sodium chloride salt granules down 1 cm. The degree of compaction can be measured by the mass to volume ratio of the sodium chloride granules.

Smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection. Firstly, 946g of pure zinc, 14g of lithium sheet and 40g of zinc-manganese intermediate alloy (Zn-20 wt.% Mn) are weighed according to the content ratio of zinc-lithium-manganese alloy Zn-0.8 wt.% Li to 0.5 wt.% Mn. Then, the zinc block is melted at 500 ℃, the lithium sheet and the zinc-manganese intermediate alloy are added, and after the lithium sheet and the zinc-manganese intermediate alloy are melted, the mixture is homogenized for half an hour.

And (3) seepage casting (the casting process is shown in figure 1): and heating the homogenized zinc-lithium alloy liquid to 560 ℃, casting the zinc-lithium alloy liquid into a mould containing sodium chloride particles preheated to 400 ℃, and sealing and pressurizing the mould to ensure that the zinc alloy liquid completely permeates into the pores of the sodium chloride particles. The gas pressure was controlled at 0.5 MP.

Washing of sodium chloride particles: and cooling the zinc alloy containing the sodium chloride particles to room temperature after the casting is finished, putting the zinc alloy into a beaker, continuously performing ultrasonic treatment by using clear water, changing the clear water for 2 hours, and repeating the ultrasonic treatment for 10 times. Fully washing away sodium chloride particles in the zinc alloy, and leaving a porous zinc alloy structure with the pore size of 100-300 mu m.

And performing linear cutting on the cleaned porous zinc alloy, and cutting out a wafer with the diameter of 8mm and the height of 3 mm. And (3) putting the cut zinc alloy into 0.5M hydrochloric acid solution for ultrasonic treatment for 10min, taking out the zinc alloy, washing the zinc alloy for three times by using clear water, and drying the zinc alloy.

Preparation of sodium alginate solution: 0.5g of sodium alginate was added to 100ml of an aqueous solution of acetic acid (Vol water: Vol acetic acid 4:1) and stirred at 700r/min for 8h until it was completely dissolved.

Adhering sodium alginate on the surface of the porous zinc alloy: pouring the above 100ml sodium alginate solution into a 100ml conical flask, adding the porous zinc alloy after acid treatment, covering with a rubber plug and vacuumizing. Treating under 0.08Mpa for 5min to make the porous zinc alloy completely immersed in sodium alginate solution.

Centrifuging to obtain a sodium alginate solution inside the porous zinc alloy: and (3) putting the porous zinc alloy immersed in the sodium alginate into a centrifuge, centrifuging for 5min at the rotating speed of 7000r/min to enable the sodium alginate solution in the porous zinc alloy to be centrifuged out, and preventing excessive sodium alginate from blocking internal holes after drying.

And (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying for 5h at the temperature of 60 ℃ to obtain the porous zinc alloy bone tissue engineering scaffold with the sodium alginate coating on the surface.

Example 5

The embodiment relates to a preparation method of a porous zinc alloy bone tissue engineering scaffold coated with a bioactive coating (chitosan coating), the pore size is 500-800 μm, the porosity is 70-90%, and zinc-lithium-silver alloy (Zn-1.4 wt.% Li-0.5 wt.% Ag) is used as a matrix. The porosity of the porous zinc alloy was measured by the drainage method, the procedure being the same as in example 1.

The method comprises the following specific implementation steps:

screening the particle size of sodium chloride particles: the sodium chloride granules pass through 20-mesh and 32-mesh sieves respectively to obtain the sodium chloride granules with the particle size range of 500-800 mu m. After the screening is finished, drying treatment is carried out for 2h at 500 ℃.

300g of sodium chloride granules are placed in a mould of the sizePreheating to 400 ℃ and preserving heat. And continuously compacting the sodium chloride particles in the process to ensure that the density of the sodium chloride particles reaches 80-90 percent. Naturally piled sodium chloride salt granules are compacted to a degree of 50% to 60% and we compact 300g of naturally piled sodium chloride salt granules down 2 cm. The degree of compaction can be measured by the mass to volume ratio of the sodium chloride granules.

Smelting of the alloy: alloy smelting is carried out in a composite furnace, and argon is introduced into the furnace for protection. Firstly, 981g of pure zinc, 14g of lithium sheets and 5g of silver particles are weighed according to the content proportion of Zn-0.8 wt.% Li in the zinc-lithium-silver alloy. Then, the zinc block was melted at 500 ℃, and the lithium pieces and silver particles were added thereto, and homogenized for half an hour after it was melted.

And (3) seepage casting (the casting process is shown in figure 1): and heating the homogenized zinc-lithium alloy liquid to 560 ℃, casting the zinc-lithium alloy liquid into a mould containing sodium chloride particles preheated to 400 ℃, and sealing and pressurizing the mould to ensure that the zinc alloy liquid completely permeates into the pores of the sodium chloride particles. The gas pressure was controlled at 0.2 MP.

Washing of sodium chloride particles: and cooling the zinc alloy containing the sodium chloride particles to room temperature after the casting is finished, putting the zinc alloy into a beaker, continuously performing ultrasonic treatment by using clear water, changing the clear water for 2 hours, and repeating the ultrasonic treatment for 10 times. Fully washing away sodium chloride particles in the zinc alloy, and leaving a porous zinc alloy structure with the pore size of 500-800 mu m.

And performing linear cutting on the cleaned porous zinc alloy, and cutting out a wafer with the diameter of 6mm and the height of 2 mm. And (3) putting the cut zinc alloy into 0.5M hydrochloric acid solution for ultrasonic treatment for 2min, taking out the zinc alloy, washing the zinc alloy for three times by using clear water, and drying the zinc alloy.

Preparation of chitosan solution: 0.75g of chitosan was added to 100ml of an aqueous solution of acetic acid (Vol water: Vol acetic acid 4:1) and stirred at 700r/min for 8h until it was completely dissolved.

Adhering chitosan on the surface of the porous zinc alloy: pouring the 100ml chitosan solution into a 100ml conical flask, putting the porous zinc alloy after acid treatment into the conical flask, covering a rubber stopper and vacuumizing. Treating under 0.08Mpa for 5min to make the porous zinc alloy completely immersed in the chitosan solution.

Centrifuging to obtain a chitosan solution inside the porous zinc alloy: and (3) putting the porous zinc alloy soaked in the chitosan into a centrifuge, centrifuging for 5min at the rotating speed of 7000r/min to enable the chitosan solution in the porous zinc alloy to be centrifuged out, and preventing excessive residual chitosan from blocking internal pores after drying.

And (3) drying treatment: and (3) putting the centrifuged porous zinc alloy into a vacuum drying oven, and carrying out vacuum drying for 5h at the temperature of 60 ℃ to obtain the porous zinc alloy bone tissue engineering scaffold with the chitosan coating on the surface.