CN108310454B

CN108310454B - Gradient biological ceramic material coated with gelatin/chitosan composite porous membrane and preparation method thereof

Info

Publication number: CN108310454B
Application number: CN201810231583.7A
Authority: CN
Inventors: 陈传忠; 李慧君; 于慧君
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2018-03-20
Filing date: 2018-03-20
Publication date: 2020-04-17
Anticipated expiration: 2038-03-20
Also published as: CN108310454A

Abstract

The invention provides a gradient biological ceramic material coated with gelatin/chitosan composite porous membrane and a preparation method thereof, the biological ceramic is a gradient β type calcium polyphosphate biological ceramic, the composite sol contains chitosan and gelatin, and the degradation rate of the material in Tris-HCl solution is improved by 2-11 times compared with that of the gradient β type calcium polyphosphate biological ceramic.

Description

Gradient biological ceramic material coated with gelatin/chitosan composite porous membrane and preparation method thereof

Technical Field

The invention belongs to the field of biological ceramic materials, and particularly relates to a gradient biological ceramic material coated with a gelatin/chitosan composite porous membrane and a preparation method thereof.

Background

Articular cartilage tissue is a porous, biphasic, viscoelastic tissue with unique biomechanical properties, consisting of an extracellular matrix and chondrocytes dispersed in the matrix. The cartilage tissue can be divided into four parts, the surface layer is connected with subchondral bone, the mechanical stress and the compression deformation caused by the flow of body fluid are gradually weakened, the pressure of the body fluid is increased, the density, the porosity and the shape of cartilage cells of each part are different, and the cartilage tissue is divided into the surface layer, the middle layer, the deep layer and the calcified layer from top to bottom.

Calcium Polyphosphate (CPP) is a Calcium phosphate-based inorganic polymer, and the main chain structure of the Calcium Polyphosphate is not formed by simple covalent bond connection but is connected through [ PO3- ] ions of a tetrahedral structure, so that the performance of the Calcium Polyphosphate can be regulated and controlled by utilizing the characteristics of the polymer and changing the structural parameters such as the polymerization degree of a material; meanwhile, calcium ions and [ PO3- ] are combined with each other by ionic bonds, so that the material can be researched by utilizing the characteristics of the calcium ions and the [ PO3- ] as inorganic matters. However, CPP has large brittleness and too low degradation speed, and cannot meet the requirement of bone repair. Composite technology is one of the important ways to solve these problems. Chitosan is a cationic polysaccharide extracted from chitin by deacetylation. The chitosan membrane has good biodegradability, biocompatibility and bioactivity, but the pore volume of the chitosan membrane is small, and the pore volume is very important for the degradation of materials and cell adhesion. Gelatin is an isomeric polypeptide compound, as a collagen, prepared by hydrolysis of extracellular matrix, and is an amphoteric polyelectrolyte capable of hydrogen bonding with water molecules. Gelatin is insoluble in most non-polar organic solvents such as alcohol, but is soluble in aqueous acetic acid and some aqueous solutions of polyols, and chitosan is also soluble in weak acid solutions such as aqueous acetic acid. Meanwhile, the gelatin has a structure similar to that of organism collagen, has lower antigenicity than natural collagen, and degradation products of the gelatin are easily absorbed by a human body, have no additional inflammatory reaction and have higher degradation speed. The pore volume directly affects the growth and degradation properties of the biomaterial cells, while gelatin has a significant impact on the pore volume of the film.

Disclosure of Invention

In order to overcome the defects, the invention provides a gradient biological ceramic material coated with a gelatin/chitosan composite porous membrane and a preparation method thereof, the biological ceramic is a gradient β type calcium polyphosphate biological ceramic, the composite sol contains chitosan and gelatin, and the degradation rate of the material in a Tris-HCl solution is improved by 2-11 times compared with that of a gradient β type calcium polyphosphate biological ceramic.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a gradient biological ceramic material coated with a gelatin/chitosan composite porous membrane comprises the following steps:

1) heating the calcium dihydrogen phosphate powder to 500 ℃ at a speed of 2-6 ℃/min, preferably at a heating speed of 3-5 ℃/min, more preferably at a heating speed of 4 ℃/min, and keeping the temperature for 2-12 h, preferably 6-11 h, more preferably 10h.

Sintering, cooling to room temperature along with the furnace, grinding, fully mixing with the binder polyvinyl alcohol, ball-milling, drying, and sieving to obtain powder 1 for later use;

2) ball-milling stearic acid, and screening 50-200 mesh pore-foaming agents, preferably 50-80 mesh or 80-120 mesh;

3) uniformly mixing the powder 1 and a pore-foaming agent with the pore diameter of 80-120 meshes according to the mass ratio of 1.5-4: 1, preferably 3:1 to obtain powder 2, and uniformly mixing the powder 1 and the pore-foaming agent with the pore diameter of 50-80 meshes according to the mass ratio of 1.5-4: 1, preferably 2.5:1 to obtain powder 3; sequentially weighing powder 1 and powder 2 according to the ratio of 1:3:7 or 1:2:8 or 1:4:6, pressing powder 3 into a cylinder with the diameter of 1cm and the height of 1cm by using a powder tablet press, wherein the preferable ratio is 1:3:7

4) And (3) heating the pressed sample to 400 ℃ at the speed of 2-6 ℃/min, preferably at the heating speed of 3-5 ℃/min, further preferably at the heating speed of 4 ℃/min, keeping the temperature for 2h, then heating to 800-900 ℃, preferably at the temperature of 850-880 ℃, further preferably at the temperature of 850 ℃, keeping the temperature for 60-120 min, preferably for 90min at the speed of 4 ℃/min.

Cooling to room temperature along with the furnace to obtain the gradient β type calcium polyphosphate bioceramic, polishing the surface of the sample by No. 600 abrasive paper, ultrasonically cleaning by alcohol, removing grease and residual powder, and drying.

5) And coating gelatin/chitosan composite sol on the surface of the gradient β type calcium polyphosphate biological ceramic to obtain the gradient biological ceramic material coated with the gelatin/chitosan composite porous membrane.

Preferably, the gelatin/chitosan composite sol contains chitosan and gelatin with the viscosity of less than or equal to 200 mPa.s.

Preferably, the concentration of the gelatin/chitosan composite sol is 3% -9%, preferably 3% -6%, more preferably 6%, and the proportion of gelatin is 1/6-5/6, more preferably 1/3-2/3.

Preferably, the specific steps of step 5) are as follows: drying the pretreated substrate, standing the prepared composite sol for 12h to remove bubbles, weighing 80g of the composite sol, placing the composite sol in a 200ml beaker, weighing 8ml of dibutyl phthalate, pouring the dibutyl phthalate into the sol, uniformly stirring, immersing the substrate in the chitosan/gelatin composite sol, soaking for 6h-48h under the constant temperature condition of 40 ℃ water bath, preferably for 24h-48h, further preferably for 24h, ultrasonically oscillating for 10min, taking out, and then drying by air blowing for 6h at 55 ℃; sequentially removing residual acetic acid and pore-forming agent dibutyl phthalate by using 0.1mol/L NaOH solution, deionized water and acetone, and drying by using a blast drying oven.

Preferably, the preparation method of the gelatin/chitosan composite sol comprises the following steps: measuring glacial acetic acid solution, dissolving in deionized water, and stirring. Weighing chitosan powder, adding the chitosan powder into deionized water, fully stirring to uniformly disperse chitosan in the deionized water, dropwise adding the prepared acetic acid solution, uniformly stirring to form chitosan sol, placing the sol at 40 ℃, adding gelatin, and uniformly stirring to form composite sol.

Preferably, the preparation method of the gelatin/chitosan composite sol comprises the following steps:

1) the volume ratio of the acetic acid solution to the deionized water is as follows: 2-8:50, preferably 4-6:50, more preferably 4:50

2) The stirring time is 12-90min, preferably 15-60min, and further preferably 30 min;

3) the proportion of the chitosan powder to the deionized water is as follows: 2 to 8g, 50ml, preferably 2 to 6g, 50ml, more preferably 2g, 50ml,3g, 50ml,4g, 50ml, and finally preferably 3g, 50ml

4) The invention also provides a gradient biological ceramic material coated with the gelatin/chitosan composite porous membrane, which is prepared by any one of the methods, wherein the mass of the gelatin is 2-8g, preferably 2-6g, more preferably 2g,3g,4g, and finally preferably 3 g.

The invention also provides a degradable biological scaffold material for cartilage or bone repair, which comprises the material with the chitosan/gelatin composite porous membrane coated on the surface by the gradient porous biological ceramic impregnation film-forming method.

The invention also provides the application of the gradient biological ceramic material coated with the gelatin/chitosan composite porous membrane in the preparation of biomedical materials.

The invention has the advantages of

(1) The invention provides a gradient biological ceramic material coated with gelatin/chitosan composite porous membrane and a preparation method thereof, which is characterized in that the used biological ceramic is a gradient β type calcium polyphosphate biological ceramic, composite sol contains chitosan and gelatin, and the degradation rate of the material is improved by 2-20 times compared with that of a gradient β type calcium polyphosphate biological ceramic in Tris-HCl solution.

(2) The preparation method is simple, high in efficiency, strong in practicability and easy to popularize.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 shows the surface morphology of the porous gelatin/chitosan composite film coated calcium polyphosphate biological ceramic material prepared in examples 1,2 and 3, wherein (a) is a chitosan solution coating material with a concentration of 6%, (b), (c) and (d) are samples prepared in examples 1,2 and 3 in sequence

FIG. 2 is a graph of mass change versus pH change after Tris-HCl solution soaking for samples prepared in examples 1,2, 3. (a: chitosan/gelatin 2:1, b: chitosan/gelatin 1:1, c: chitosan/gelatin 1: 2);

FIG. 3 is the mass change of the samples prepared in example 2 after soaking in Tris-HCl solution and the chitosan-coated samples with 6% concentration

FIG. 4 is a phase change diagram after soaking in Tris-HCl solution. (a1, a2: chitosan/gelatin 2:1, b1, b2: chitosan/gelatin 1:1, c1, c2: chitosan/gelatin 1: 2.7 days: a1, b1, c1, cpp-1; 14 days: a2, b2, c2, cpp-2);

FIG. 5 is a scan of the surface microtopography before and after soaking in Tris-HCl solution. (a, a1, a2: chitosan/gelatin 2:1, b, b1, b2: chitosan/gelatin 1:1, c, c1, c2: chitosan/gelatin 1: 2. unsubmerged: a, b, c, 7 days: a1, b1, c 1; 14 days: a2, b2, c 2);

FIG. 6 is a Fourier infrared spectrum change before and after soaking in Tris-HCl solution. (a1, a2: chitosan/gelatin 2:1, b1, b2: chitosan/gelatin 1:1, c1, c2: chitosan/gelatin 1: 2.7 days: a1, b1, c 1; 14 days: a2, b2, c 2);

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The present invention will be further described with reference to specific examples.

Example 1

1) Preparation of porous bioceramics

The ceramic raw material is calcium dihydrogen phosphate, and the selected pore-forming agent is stearic acid. The binder is polyvinyl alcohol (5% PVA) and is sintered in a box furnace, and an alumina crucible is selected. The ceramic sintering process is divided into two steps, wherein the pre-sintering process comprises the steps of pouring calcium dihydrogen phosphate powder into a crucible, heating to 500 ℃ at a speed of 5 ℃/min, preserving heat for 10 hours, cooling to room temperature along with a furnace, and taking out. Roughly grinding by using a mortar, fully mixing the mixture with polyvinyl alcohol serving as a binder according to the mass ratio of 5%, pouring the mixture into a ball milling tank, adding a proper amount of deionized water (without powder), ball milling by using a ball mill at the speed of 230r/h for 1h, taking out the mixture, drying the mixture in a blast drying oven at the temperature of 55 ℃, and screening powder 1 with the particle size of less than 200 meshes by using a 200-mesh sieve for later use. Ball-milling stearic acid, and screening to 50-80 meshes or 80-120 meshes; uniformly mixing powder 1 and a pore-foaming agent with the pore diameter of 80-120 meshes according to the mass ratio of 3:1 to obtain powder 2, and uniformly mixing the powder 1 and the pore-foaming agent with the pore diameter of 50-80 meshes according to the mass ratio of 2.5:1 to obtain powder 3; sequentially weighing powder 1 and powder 2 according to the ratio of 1:3:7, and pressing the powder 3 into a cylinder with the diameter of 1cm and the height of 1cm by using a powder tablet press. Placing the pressed sample on an alumina ceramic tray, laying a layer of alumina powder on the bottom of the alumina ceramic tray, heating to 400 ℃ at the speed of 5 ℃/min in a box-type furnace, preserving heat for 120min, heating to 880 ℃ again, preserving heat for 90min, and cooling to room temperature along with the furnace.

And (3) grinding the surface of the sample into a thin layer by using fine 600# abrasive paper, then ultrasonically cleaning the sample by using alcohol, removing grease and residual powder, and drying the sample for later use.

2) Preparing gelatin/chitosan composite sol:

a glacial acetic acid solution of 4mL is measured, dissolved in deionized water of 50mL and stirred for 30 min. Weighing 3g of chitosan powder, adding the chitosan powder into 50mL of deionized water, fully stirring to uniformly disperse chitosan in the deionized water, dropwise adding the prepared acetic acid solution, stirring for 2 hours to form uniform chitosan sol, placing the sol at 40 ℃, adding 3g of gelatin, and uniformly stirring to form composite sol with the proportion of chitosan being 1/2 respectively.

3) Gelatin/chitosan composite sol coating

Putting 80g of the composite sol prepared in the step 2) into a 200ml beaker, weighing 8ml of dibutyl phthalate, pouring the dibutyl phthalate into the sol, uniformly stirring, immersing the substrate into the chitosan/gelatin composite sol, soaking for 24 hours under the constant temperature condition of 40 ℃ water bath, ultrasonically oscillating for 10 minutes, taking out, and drying for 6 hours by blowing at 55 ℃; sequentially removing residual acetic acid and pore-forming agent dibutyl phthalate by using 0.1mol/L NaOH solution, deionized water and acetone, and drying by using a blast drying oven.

Example 2

1) Preparing porous bioceramic: same as example 1

2) Preparing gelatin/chitosan composite sol:

a glacial acetic acid solution of 4mL is measured, dissolved in deionized water of 50mL and stirred for 30 min. Weighing 2g of chitosan powder, adding the chitosan powder into 50mL of deionized water, fully stirring to uniformly disperse chitosan in the deionized water, dropwise adding the prepared acetic acid solution, stirring for 2 hours to form uniform chitosan sol, placing the sol at 40 ℃, adding 4g of gelatin, and uniformly stirring to form composite sol with the proportion of chitosan being 1/3 respectively.

3) Coating with gelatin/chitosan composite sol: same as example 1

Example 3

1) Preparing porous bioceramic: same as example 1

2) Preparing gelatin/chitosan composite sol:

a glacial acetic acid solution of 4mL is measured, dissolved in deionized water of 50mL and stirred for 30 min. Weighing 4g of chitosan powder, adding the chitosan powder into 50mL of deionized water, fully stirring to uniformly disperse chitosan in the deionized water, dropwise adding the prepared acetic acid solution, stirring for 2 hours to form uniform chitosan sol, placing the sol at 40 ℃, adding 2g of gelatin, and uniformly stirring to form composite sol with the proportion of chitosan being 2/3 respectively.

3) Coating with gelatin/chitosan composite sol: same as example 1

And (3) performance testing:

1. the surface morphology of the porous gelatin/chitosan composite film coated calcium polyphosphate biological ceramic material prepared in the examples 1,2 and 3 is shown in fig. 1, wherein (a) is a chitosan solution coating material with the concentration of 6%, and (b), (c) and (d) are the materials prepared in the examples 1,2 and 3 in sequence. As can be seen from fig. 1, as the content of gelatin increases, the cavity volume of the film layer gradually increases due to electrostatic interaction between the gelatin and chitosan molecules.

2. The porous gelatin/chitosan composite film prepared in the examples 1,2 and 3 is coated with a calcium polyphosphate biological ceramic material, and the uncoated calcium polyphosphate biological ceramic material is soaked in a Tris-HCl solution according to the mass volume ratio of 1g/20ml, is subjected to constant temperature water bath at 37 ℃, is replaced with water every other day, and is used for measuring the pH value of the solution. Soaking for 3 days, 7 days and 14 days respectively, taking out, sequentially removing surface residual ions by using deionized water and absolute ethyl alcohol, drying, and weighing the weight to obtain the weight loss ratio before and after soaking. FIG. 2 is a graph showing the comparison of the weight loss ratio of the porous gelatin/chitosan composite film coated calcium polyphosphate biological ceramic material in Tris-HCl solution and the weight loss ratio of the calcium polyphosphate biological ceramic material, and the change of pH value during the soaking process. From the 7 th day of soaking, the weight loss of the material obtained by the chitosan/gelatin ratio of 1:1 is particularly obvious, and after the material is soaked for 14 days, the maximum degradation rate of the composite ceramic material is 5.33 percent, and compared with 0.48 percent of pure calcium polyphosphate biological ceramic, the degradation rate is improved by 11 times. In the soaking process, the pH value can be seen to be changed between 7.2 and 7.4 all the time, and the degradation process can be maintained in a weak alkali environment which is beneficial to a human body.

3. Fig. 3 shows that the weight loss rate of the porous gelatin/chitosan composite film layer coated calcium polyphosphate biological ceramic material prepared in example 2 and the chitosan solution coated calcium polyphosphate material with the concentration of 6% in the Tris-HCl solution is 5.33% after soaking for 14 days, and compared with 4.16% of the biological ceramic coated with chitosan with the same concentration, the degradation rate is improved by 1.28 times.

4. Fig. 4 the porous gelatin/chitosan composite membrane layer coated calcium polyphosphate bio-ceramic material prepared in examples 1,2 and 3 was soaked in Tris-HCl solution for 7 days, (a1: chitosan/gelatin 2:1, b1: chitosan/gelatin 1:1, c1: chitosan/gelatin 1:2) for 14 days (a2: chitosan/gelatin 2:1, b2: chitosan/gelatin 1:1, c2: chitosan/gelatin 1:2) and then phase change was observed

5. FIG. 5 is a scanning image of the surface microtopography before and after soaking in Tris-HCl solution. Soaking for 7 days (a1: chitosan/gelatin 2:1, b1: chitosan/gelatin 1:1, c1: chitosan/gelatin 1: 2); after 14 days (a2: chitosan/gelatin 2:1, b2: chitosan/gelatin 1:1, c2: chitosan/gelatin 1: 2). After 7 days of soaking, the surface a is adhered with flakes, the surface c is adhered with rods, after 14 days of soaking, the flakes on the surface a are degraded into smaller particles, and the rods on the surface c are split into clustered needles. And b, the surface film layer of the calcium polyphosphate film is gradually degraded along with the increase of the soaking time, and the degradation of the ceramic particles close to the film layer is reduced when the calcium polyphosphate film is soaked for 7 days, because the chitosan and the sol have certain swelling rates, the effect of ions in water and a solution on the calcium polyphosphate particles can be accelerated.

6. FIG. 6 changes in Fourier infrared spectra before and after immersion in Tris-HCl solution. No soaking (a: chitosan/gelatin 2:1, b: chitosan/gelatin 1:1, c: chitosan/gelatin 1: 2); soaking for 7 days (a1: chitosan/gelatin 2:1, b1: chitosan/gelatin)Gum 1:1, c1 chitosan/gelatin 1: 2); 14 days (a2: chitosan/gelatin 2:1, b2: chitosan/gelatin 1:1, c2: chitosan/gelatin 1: 2); along with the increase of the soaking time, the length of the soaking time is 3400cm^-1The stretching vibration peak of-OH which is formed by hydrogen bond association nearby is gradually narrowed, which shows that hydrogen bond acting force existing between chitosan, gelatin and calcium polyphosphate is reduced. P-O-P, and 1100cm^-1The nearby P-O decreases.

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereto, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications and equivalents can be made in the technical solutions described in the foregoing embodiments, or equivalents thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims

1. A method for preparing a gradient biological ceramic material coated with gelatin/chitosan composite porous membrane, which is characterized in that,

coating gelatin/chitosan composite sol on the surface of the gradient β type calcium polyphosphate bioceramic, wherein the gelatin/chitosan composite sol contains chitosan and gelatin with the viscosity of 50-200mPa.s, the concentration of the gelatin/chitosan composite sol is 3% -9%, and the gelatin accounts for 1/6-5/6;

the preparation method of the gradient β type calcium polyphosphate biological ceramic comprises the following steps:

1) heating the calcium dihydrogen phosphate powder to 500 ℃ at the speed of 2-6 ℃/min, and keeping the temperature for 2-12 h;

2) ball-milling stearic acid, and screening a pore-forming agent of 50-200 meshes;

3) uniformly mixing the powder 1 and a pore-foaming agent with the pore diameter of 80-120 meshes according to the mass ratio of 1.5-4: 1 to obtain powder 2, and uniformly mixing the powder 1 and the pore-foaming agent with the pore diameter of 50-80 meshes according to the mass ratio of 1.5-4: 1 to obtain powder 3; sequentially weighing powder 1 and powder 2 according to the ratio of 1:3:7 or 1:2:8 or 1:4:6, and pressing the powder 3 into a cylinder with the diameter of 1cm and the height of 1cm by using a powder tablet press;

4) raising the temperature of the pressed sample to 400 ℃ at the speed of 2-6 ℃/min, preserving the heat for 2h, then raising the temperature to 800-900 ℃ at the speed of 4 ℃/min, and preserving the heat for 60-120 min;

cooling to room temperature along with the furnace to obtain the gradient β type calcium polyphosphate bioceramic.

2. The method according to claim 1, wherein in the step (1) of preparing the gradient β type calcium polyphosphate bioceramic, the temperature rising speed is 3 ℃/min to 5 ℃/min.

3. The method according to claim 1, wherein in the step (1) of preparing the calcium polyphosphate bioceramic type gradient β, the temperature rising speed is 4 ℃/min.

4. The method according to claim 1, wherein the step (1) of preparing the calcium polyphosphate bioceramic with the gradient β type is carried out for 6-11 hours.

5. The method according to claim 1, wherein the step of preparing the gradient β type calcium polyphosphate bioceramic in step (1) is performed for 10 hours.

6. The method according to claim 1, wherein in the step (2) of preparing the gradient β type calcium polyphosphate bioceramic, stearic acid is subjected to ball milling, and a pore-forming agent of 80-120 meshes is screened out.

7. The method according to claim 1, wherein in the step (2) of preparing the gradient β type calcium polyphosphate bioceramic, stearic acid is subjected to ball milling, and a pore-forming agent of 50-80 meshes is screened out.

8. The method according to claim 1, wherein in the step (3) of preparing the gradient β type calcium polyphosphate bioceramic, the powder 1 and the pore-forming agent with the pore diameter of 80-120 meshes are uniformly mixed according to the mass ratio of 3:1 to obtain the powder 2, and the powder 1 and the pore-forming agent with the pore diameter of 50-80 meshes are uniformly mixed according to the mass ratio of 2.5:1 to obtain the powder 3.

9. The method of claim 1, wherein in the step (4) of preparing the calcium polyphosphate bioceramic type gradient β, the pressed sample is raised to 400 ℃ at a rate of 3 ℃/min to 5 ℃/min.

10. The method of claim 1, wherein in step (4) of preparing the gradient β type calcium polyphosphate bioceramic, the pressed sample is raised to 400 ℃ at a rate of 4 ℃/min.

11. The method of claim 1, wherein after the incubation time of 2 hours, the temperature is raised to 850 ℃ to 880 ℃ at a rate of 4 ℃/min.

12. The method according to claim 1, wherein in the step (4) of preparing the calcium polyphosphate bioceramic type gradient β, after the heat preservation is carried out for 2 hours, the temperature is raised to 850 ℃ at a rate of 4 ℃/min.

13. The method as claimed in claim 1, wherein in the step (4) of preparing the gradient β type calcium polyphosphate bioceramic, after the heat preservation is carried out for 2 hours, the temperature is raised to 800-900 ℃ at a rate of 4 ℃/min, and the heat preservation is carried out for 90 min.

14. The method according to claim 1, wherein the concentration of the gelatin/chitosan composite sol is 3% to 6%.

15. The method of claim 1, wherein the gelatin/chitosan composite sol has a concentration of 6%.

16. The method of claim 1, wherein the gelatin is present in a proportion of 1/3-2/3.

17. The method of claim 1, wherein the gelatin is present in a proportion of 1/2.

18. The method of claim 1, comprising the specific steps of: drying the pretreated substrate, standing the prepared composite sol for 12h to remove bubbles, weighing 80g of the composite sol, putting the composite sol into a 200ml beaker, weighing 8ml of dibutyl phthalate, pouring the dibutyl phthalate into the sol, uniformly stirring, immersing the substrate into the chitosan/gelatin composite sol, soaking for 6h-48h under the constant temperature condition of a water bath at 40 ℃, ultrasonically shaking for 10min, taking out, and then drying by air blowing for 6h under the condition of 55 ℃; sequentially removing residual acetic acid and pore-forming agent dibutyl phthalate by using 0.1mol/L NaOH solution, deionized water and acetone, and drying by using a blast drying oven.

19. The method of claim 18, wherein the soaking time is from 24 hours to 48 hours.

20. The method of claim 18, wherein the soaking time is 24 hours.

21. The method of claim 1, wherein the gelatin/chitosan composite sol is prepared by the following steps: measuring glacial acetic acid solution, dissolving in deionized water, uniformly stirring, weighing chitosan powder, adding into deionized water, fully stirring to uniformly disperse chitosan in deionized water, dropwise adding the prepared acetic acid solution, uniformly stirring to form chitosan sol, placing the sol at 40 ℃, adding gelatin, and uniformly stirring to form composite sol.

22. The method of claim 21,

the preparation method of the gelatin/chitosan composite sol comprises the following steps:

1) the volume ratio of the acetic acid solution to the deionized water is as follows: 2-8: 50; 2) the stirring time is 12-90 min;

3) the proportion of the chitosan powder to the deionized water is as follows: 2-8g, 50 ml;

4) the gelatin has a mass of 2-8 g.

23. The method of claim 22, wherein in step (1) of the preparation method of the gelatin/chitosan composite sol, the volume ratio of the acetic acid solution to the deionized water is 4-6: 50.

24. The method of claim 22, wherein in step (1) of the method for preparing the gelatin/chitosan composite sol, the volume ratio of the acetic acid solution to the deionized water is 4: 50.

25. The method according to claim 22, wherein the stirring time is 15 to 60min in the step (2) of the method for preparing the gelatin/chitosan composite sol.

26. The method according to claim 22, wherein the stirring time is 30min in the step (2) of the method for preparing the gelatin/chitosan composite sol.

27. The method of claim 22, wherein in the step (3) of the preparation method of the gelatin/chitosan composite sol, the ratio of the chitosan powder to the deionized water is 2-6g:50 ml.

28. The method according to claim 22, wherein in the step (3) of the preparation method of the gelatin/chitosan composite sol, the ratio of the chitosan powder to the deionized water is 3g:50 ml.

29. The method according to claim 22, wherein the gelatin has a mass of 2 to 6g in the step (4) of the method for preparing the gelatin/chitosan composite sol.

30. The method of claim 22, wherein the gelatin has a mass of 2g,3g, or 4g in step (4) of the method for preparing the gelatin/chitosan composite sol.

31. The method for preparing a gradient biological ceramic material coated with gelatin/chitosan composite porous membrane as claimed in claim 1,

and (3) polishing the surface of the gradient β type calcium polyphosphate bioceramic by using No. 600 abrasive paper, ultrasonically cleaning the surface by using alcohol, removing grease and residual powder, and drying the surface.

32. A gradient bioceramic material coated with a gelatin/chitosan composite porous membrane prepared by the method of any one of claims 1 to 31.

33. A degradable biological scaffold material for cartilage or bone repair, which comprises the material of gelatin/chitosan composite porous membrane coated on the surface by the gradient porous bioceramic impregnation film-forming method of claim 32.

34. Use of the gradient bioceramic coated gelatin/chitosan composite porous membrane of claim 32 in the manufacture of biomedical materials.