CN113201222A - Yak skin glue/PMVE-MA composite material and preparation method and application thereof - Google Patents

Abstract

The invention provides a yak skin glue/PMVE-MA composite material which is formed by compounding yak skin glue and PMVE-MA according to the mass ratio of (4-8) to 1. The yak hide gelatin/PMVE-MA composite material has excellent swelling degree and mechanical property, the degradation rate can meet the time requirement of implanting the scaffold material into the body, the microstructure meets the condition of cell adhesion growth, and the yak hide gelatin/PMVE-MA composite material has low hemolysis rate and has excellent potential as a tissue engineering scaffold material.

Description

Yak skin glue/PMVE-MA composite material and preparation method and application thereof

Technical Field

The invention belongs to the field of composite materials, and particularly relates to a yak skin gum/PMVE-MA composite material and a preparation method and application thereof.

Background

In recent years, composite scaffold materials become a research hotspot in the field of medical tissue engineering, compared with traditional metals and high polymer materials, natural biological materials have the characteristics of degradability, no toxicity of degradation products, good biocompatibility and the like, and are main raw materials for preparing degradable tissue engineering scaffold materials. Animal gelatin, a natural biomaterial, has been widely used in the field of tissue engineering. Methyl vinyl ether/maleic anhydride copolymers (PMVE-MA) are a class of FDA approved acid glycoside polymers that have the advantages of biodegradability and low toxicity, have found applications in wound healing research, and have also been used to encapsulate pharmaceuticals to enhance bioadhesion. Therefore, the gelatin and PMVE-MA are compounded into the composite material, the performance and the application in the field of tissue engineering are explored, and a new choice is provided for the field of tissue engineering materials.

Hemlata Chhabra^[1]The inventors have succeeded in preparing a gelatin/PMVE-MA composite stent which, despite its low hemolysis rate, has a high degree of water-swelling up to 1200%. An excessively high swelling ratio means that excessive water enters the interior of the stent, so that not only can the pressure on the stent from inside to outside be generated to increase the pore diameter of the stent, collapse the structure, reduce the mechanical strength and accelerate the degradation rate, but also the 'scouring' effect can be generated on cells adhered to the surface of the stent at the initial stage to cause the shedding of the adhered cells, thereby influencing the regeneration of tissues; in addition, the stent has low mechanical strength, compression modulus below 50MPa, easy destruction and difficult supportThe site of injury.

The yak skin glue is gelatin which is extracted from yak skin and contains rich nutrient components, and because the growth conditions of yaks are different from those of other animals, the yak skin glue extracted from the Qinghai-Tibet plateau yaks not only contains more abundant nutrient substances, but also has higher thermal stability than gelatin of other animals. Yak skin is the waste of meat processing, only a few of the yak skin is used for manufacturing leather products, most yak skin is usually discarded, high-content protein in the yak skin is not effectively utilized, serious resource waste and environmental pollution are caused, if the yak skin can be applied to the field of tissue engineering, the pollution to the environment can be reduced, and the nutritional ingredients in the yak skin can be fully utilized.

Therefore, the research on the tissue engineering material taking the yak skin gum as the matrix has great advantages and important economic value.

Disclosure of Invention

The invention aims to provide a yak skin gum/PMVE-MA composite material.

The invention provides a yak skin glue/PMVE-MA composite material, which is formed by compounding yak skin glue and PMVE-MA; the mass ratio of the yak hide glue to the PMVE-MA is (4-8): 1, and preferably 6: 1.

Further, the hemolysis rate of the composite material is not higher than 5%, preferably 0.1% to 1.6%.

Further, the compression modulus of the composite material is not less than 300MPa, and preferably 391-468 MPa.

Further, the maximum swelling degree of the composite material is not more than 100%, and preferably 54% to 72%.

Furthermore, the composite material is prepared by blending yak skin glue and PMVE-MA according to a proportion, pre-freezing and freeze-drying the mixture, and soaking the mixture in HMDI solution.

Still further, the above blending is: mixing yak hide gelatin and PMVE-MA in proportion, and stirring at 37-55 ℃ for 1-4 hours; and/or the pre-freezing is: freezing at-50 deg.c to-100 deg.c; and/or the soaking is: soaking in HMDI solution for 1-3 hours; preferably, the HMDI solution has a mass concentration of 10%.

The invention provides a preparation method of the composite material, which comprises the following steps: mixing yak hide gelatin and PMVE-MA at a certain proportion, pre-freezing, freeze-drying, and soaking in HMDI solution.

Further, the preparation method comprises the following steps:

(1) mixing yak skin gelatin solution and PMVE-MA solution at a certain proportion;

(2) stirring for 2-3 hours at 37-55 ℃ to obtain a mixed solution;

(3) the mixed solution is pre-frozen at the temperature of between 50 ℃ below zero and 100 ℃ below zero and then is freeze-dried;

(4) and soaking the freeze-dried stent material in an HMDI solution for 1-3 hours.

The solution of the yak skin gum is preferably an ethanol solution of the yak skin gum; the solution of PMVE-MA is preferably an ethanol solution of PMVE-MA; the HMDI solution concentration is preferably 10%.

The invention also provides the application of the composite material in an implant material in vivo, preferably in a tissue engineering scaffold.

Experimental results show that the yak skin gelatin/PMVE-MA composite material has excellent swelling degree and mechanical property, the degradation rate can meet the time requirement of implanting the scaffold material into a body, the microstructure meets the condition of cell adhesion growth, and the yak skin gelatin/PMVE-MA composite material has low hemolysis rate and has excellent potential as a tissue engineering scaffold material.

The PMVE-MA of the invention refers to: methyl vinyl ether/maleic anhydride copolymers; HMDI refers to: hexamethylene diisocyanate. The maximum swelling degree refers to the swelling degree when the quality of the composite material after water absorption and swelling does not change with time and shows statistically significant change.

Obviously, many modifications, substitutions, and variations are possible in light of the above teachings of the invention, without departing from the basic technical spirit of the invention, as defined by the following claims.

The present invention will be described in further detail with reference to the following examples. This should not be understood as limiting the scope of the above-described subject matter of the present invention to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention.

Drawings

FIG. 1: the influence of the composition ratio (mass ratio of yak-hide gelatin: PMVE-MA) on the hemolysis rate of the scaffold material (the marked difference indicates the marked difference of the sample material, the marked difference indicates the marked difference of the control material, or the marked difference indicates that P <0.05, the marked difference, or the marked difference indicates that P <0.01, and the marked difference).

FIG. 2: the effect of the stirring temperature on the hemolysis rate of the scaffold material (# indicates the differential significance of the sample material, # indicates the differential significance of the control material or # indicates P <0.05, the differential significance; # or # # indicates P <0.01, the differential significance).

FIG. 3: the effect of the stirring time on the hemolysis rate of the scaffold material (# indicates the differential significance of the sample material, # indicates the differential significance of the control material or # indicates P <0.05, the differential significance; # or # # indicates P <0.01, the differential significance).

FIG. 4: effect of prefreezing temperature on the hemolysis rate of the scaffold material.

FIG. 5: effect of HMDI soak time on the hemolysis rate of the scaffold material.

FIG. 6: contour lines and response surfaces of interaction of proportioning and stirring temperature.

FIG. 7: the ratio and the stirring time interact with contour lines and response surfaces.

FIG. 8: contour lines and response surfaces of the interaction of stirring temperature and stirring time.

FIG. 9: microstructure of the composite scaffold material.

FIG. 10: the swelling degree (a) and the degradation rate (b) of the composite scaffold material change at different times.

Detailed Description

Materials and reagents:

yak skin glue (self-made in laboratories, the preparation method refers to the method disclosed in Xu M, Wei L, Xiao Y, et al. Molecular structural Properties of expressed gel from Yak skin as analyzed on Molecular weight [ J ]. International Journal of Food Properties, 2017: 10942912.2017.1300813.); PMVE-MA (Technology, Inc., Yinaoka, Beijing); glacial acetic acid (analytical grade, guano chemical technologies, shanghai); physiological saline (Shandong Hualu pharmaceutical Co., Ltd.); PBS (beijing solibao technologies ltd); HMDI (Beijing Yinaoka technologies, Inc.); isopropanol (analytical grade, guano chemical technologies, inc.).

Instruments and equipment:

electronic balance (AL105, mettler-toledo instruments (shanghai) ltd); a heating type magnetic stirrer (heating type 1EA, beijing sailuo scientific ltd); a freeze drier (FD-1A-80+, Beijing Bo Yi kang laboratory instruments Co., Ltd.); ultra-low temperature refrigerator (DW-HL398S, Mitsubishi); an automatic water purifier (UPH-I-40L, Sichuan super pure technology, Inc.); a multifunctional microplate reader (Perinemer Enspire Corp.); bench top high speed refrigerated centrifuge (Sigma 3-18ks,); digital display constant temperature water bath (HH-8, Shanghai Instrument science and technology, Inc.); a microcomputer controlled electronic universal tester (C45.105); scanning electron microscope (hitachi SU 8010).

Example 1 preparation of Yak skin gel/PMVE-MA composite scaffolds of the present invention

Respectively dissolving a yak skin gelatin solution (8% w/v) and a PMVE-MA solution (1.33% w/v) by using 0.5mol/L acetic acid solution, mixing the two solutions in a ratio of 1:1 (the mass ratio of the yak skin gelatin to the PMVE-MA is 6: 1), magnetically stirring for 3.85h at 41 ℃, pouring the stirred mixed solution into a proper mold, freezing for 24h at-80 ℃, freeze-drying, soaking the freeze-dried material sample in a 10% HMDI (prepared by isopropanol) solution for 2h, washing with isopropanol for two times, naturally volatilizing the isopropanol, and washing with pure water for three times.

Example 2 preparation of Yak skin gel/PMVE-MA composite scaffolds of the present invention

Respectively dissolving a yak skin gelatin solution (8% w/v) and a PMVE-MA solution (1% w/v) by using 0.5mol/L acetic acid solution, mixing the two solutions in a ratio of 1:1 (the mass ratio of the yak skin gelatin to the PMVE-MA is 8: 1), magnetically stirring for 4 hours at 55 ℃, pouring the stirred mixed solution into a proper mold, freezing for 24 hours at-50 ℃, freeze-drying, soaking the freeze-dried material sample in a 10% HMDI (prepared by isopropanol) solution for 3 hours, washing with isopropanol for two times, naturally volatilizing the isopropanol, and washing with pure water for three times to obtain the yak skin gelatin.

Example 3 preparation of Yak skin gel/PMVE-MA composite scaffolds of the present invention

Respectively dissolving a yak skin gelatin solution (8% w/v) and a PMVE-MA solution (2% w/v) by using 0.5mol/L acetic acid solution, mixing the two solutions in a ratio of 1:1 (the mass ratio of the yak skin gelatin to the PMVE-MA is 4: 1), magnetically stirring for 1h at 37 ℃, pouring the stirred mixed solution into a proper mold, freezing for 24h at-100 ℃, freeze-drying, soaking the freeze-dried material sample in a 10% HMDI (prepared by isopropanol) solution for 1h, washing with isopropanol for two times, naturally volatilizing the isopropanol, and washing with pure water for three times.

The beneficial effects of the composite material of the invention are demonstrated by the following experimental examples.

Experimental example 1 Single factor test screening of Yak skin glue/PMVE-MA of the invention

1. Influence of concentration ratio (yak skin gelatin: PMVE-MA) on hemolysis rate of stent material

Under the conditions of stirring time of 2h, stirring temperature of 20 ℃, pre-freezing temperature of-80 ℃ and 10% HMDI soaking time of 2h, determining the hemolysis rate of the composite scaffold material when the ratio of the yak skin gelatin to the PMVE-MA is 1:1, 1:2, 2:1 and 4:1, and determining the optimal ratio (ratio refers to mass ratio) of the two components.

FIG. 1 shows that the control material without PMVE-MA polymer component has the lowest hemolysis rate, and less than 5%, which is considered as the material does not cause hemolysis reaction. After the PMVE-MA polymer is added, except for the material with the component ratio of 4:1, the hemolysis rates of the materials with other ratios are obviously increased, wherein when the concentration ratio of the two materials is 1:1, the hemolysis rate of the material reaches the highest and is far higher than 5%, and when the component ratios are 1:2 and 2:1, the hemolysis rate of the material is obviously lower than that of the material with the concentration ratio of 1:1, but still higher than 5%, so that the material is considered to cause hemolysis reaction. The addition of the polymer PMVE-MA causes a reaction between two main components of the stent material, and further influences the hemolysis rate of the composite stent material, and the hemolysis rate determination result shows that PMVE-MA with higher concentration has a certain influence on the hemolysis rate of the material, while the addition of PMVE-MA with low concentration has no obvious influence on the hemolysis rate of the stent material. Therefore, the optimal ratio of the yak skin glue to the PMVE-MA is more than 4: 1.

2. Effect of agitation temperature on hemolysis Rate of Stent Material

Respectively measuring the hemolysis rate of the composite scaffold material at the magnetic stirring temperature of 20 ℃, 37 ℃, 45 ℃ and 55 ℃ under the conditions that the ratio of the yak skin gelatin to the PMVE-MA is 4:1, the stirring time is 2h, the pre-freezing temperature is-80 ℃, and the 10% HMDI solution is soaked for 2h, and determining the optimal magnetic stirring temperature.

Experiments show that when the stirring temperature is 20 ℃ (room temperature), the yak skin gelatin and PMVE-MA can not fully react. As can be seen from fig. 2, in the preparation process of the scaffold material, the stirring temperature has almost opposite influences on the sample material and the reference material, the hemolysis rate of the sample material decreases with the increase of the stirring temperature, and the hemolysis rate of the reference material increases, but the hemolysis rate of the scaffold material prepared at each stirring temperature is lower than 5%, i.e. the material prepared at each stirring temperature does not cause hemolysis reaction. Regardless of the condition of the stirring temperature of 20 ℃ with insufficient reaction, the hemolysis rates of the reference material and the sample material are relatively low at the stirring temperature of 45 ℃, compared with the reference material at 45 ℃, the hemolysis rate of the reference material at 55 ℃ is remarkably increased, and the hemolysis rates of the sample and the reference material at the rest temperatures are not significantly different from the hemolysis rate of the material at 45 ℃, but are higher than the hemolysis rate of the material prepared at 45 ℃. Therefore, the stirring temperature is preferably 37 to 55 ℃ and the most preferable stirring temperature is 45 ℃.

3. Effect of stirring time on the hemolysis rate of the scaffold Material

Respectively measuring the hemolysis rate of the composite scaffold material in the magnetic stirring time of 0.5h, 1h, 2h, 3h and 4h under the conditions that the ratio of the yak skin gelatin to the PMVE-MA is 4:1, the stirring temperature is 20 ℃, the pre-freezing temperature is-80 ℃, and the 10% HMDI solution is soaked for 2h, and determining the optimal magnetic stirring time.

Experiments prove that too short stirring time can cause insufficient reaction between the yak skin gelatin and PMVE-MA and the hemolysis rate of the material is relatively low. The experimental results are shown in fig. 3, the hemolysis rates of all the materials are lower than 5%, but when the stirring time is 3h, the hemolysis rates of the control and sample materials are lowest, compared with the material of 3h, the hemolysis rates of the control, sample material and sample material of 1h are very different from them, and the hemolysis rates of the sample material of 2h are very different from them. Therefore, the stirring time is preferably 1 to 4 hours, and the most preferable stirring time is 3 hours.

4. Effect of prefreezing temperature on hemolysis rate of scaffold Material

Respectively measuring the hemolysis rate of the composite scaffold material at the pre-freezing temperature of-20 ℃, 80 ℃ below zero and 196 ℃ below zero under the conditions that the ratio of the yak skin gelatin to the PMVE-MA is 4:1, the stirring time is 2h, the stirring temperature is 20 ℃, and the 10% HMDI solution is soaked for 2h, and determining the optimal pre-freezing temperature.

FIG. 4 shows that the hemolysis rate of the composite scaffold material did not change significantly at each prefreezing temperature, with hemolysis rates below 5%, where the hemolysis rates of the control and sample materials were relatively lowest at the prefreezing temperature of-196 ℃. According to the experimental condition, when the pre-freezing temperature is-20 ℃, in the process of transferring the material from the mold to a corresponding container for freeze-drying, the surface of a frozen material sample is easy to melt, and under the condition of the pre-freezing temperature of-196 ℃, the mixed solution after magnetic stirring needs to be placed in a liquid nitrogen environment for freezing, so that the operation is difficult, and in the freezing process, the liquid nitrogen easily flows into the mold and contacts with the material to influence the performance of the material. Therefore, the prefreezing temperature is preferably in the range of-50 ℃ to-100 ℃.

5. Effect of HMDI soak time on the hemolysis rate of the scaffold Material

The method comprises the steps of respectively measuring the hemolysis rate of the composite scaffold material in 10% HMDI solution for 1h, 2h and 3h under the conditions that the ratio of yak skin gelatin to PMVE-MA is 4:1, the stirring temperature is 20 ℃, the stirring time is 2h, and the pre-freezing temperature is-80 ℃, and determining the optimal soaking time.

As can be seen from fig. 5, as the soaking time of the 10% HMDI solution is prolonged, the hemolysis rate of the composite scaffold material is slightly increased, but the hemolysis rate of the material is all around 1%, which indicates that the soaking time has no significant effect on the hemolysis rate of the composite scaffold material. Therefore, the HMDI solution is suitable for soaking for 1-3 h.

Experimental example 2 response surface test

1. Method of producing a composite material

On the basis of a single-factor experiment, a preparation condition experiment (shown in table 1) of the yak skin gel/PMVE-MA composite scaffold material is optimized by adopting a Box-Behnken design by taking the ratio (yak skin gel: PMVE-MA), the stirring temperature and the stirring time as independent variables and the hemolysis rate of the scaffold material as a response value.

TABLE 1 level table of design factors of response surface

2. Results

(1) Response surface test results:

design-expert 8.0.6 software was used for data processing, and Table 2 shows the Design and results of the Box-Behnken experiment.

TABLE 2 Box-Behnken Experimental design and results

(2) Establishing a regression model and analyzing variance:

and establishing a model by taking the ratio (yak skin gelatin: PMVE-MA) (A), the stirring temperature (B) and the stirring time (C) as response variables and the hemolysis rate (Y) as a response value. Adopting Design-Expert 8.0.6 software to perform multiple regression analysis on the data in the table 2, and manually optimizing to obtain a model equation of hemolysis rate to three factors of proportion, stirring temperature and stirring time:

Y＝+1.91+4.06*A+0.045*B-0.33*C-0.33*A*B-0.34*A*C-0.037*B*C+2.50 *A²+0.32*B²-0.079*C²

results of the analysis of variance of Table 3Show that F-401.77, P for this model<0.0001, the model is high in significance, and the model is good in reliability. The regression model analysis of variance results show that the proportion and the stirring time have extremely obvious influence on the hemolysis rate of the material, and can be judged according to the F value, and the significance sequence of the influence of the three factors on the hemolysis rate of the material is as follows in the horizontal range of each factor selected in the experiment: ratio (A)>Mixing time (C)>The stirring temperature (B) has no significance on the influence of the stirring temperature (B) on the hemolysis rate of the material, and the influence sequence of the interaction among the factors on the hemolysis rate is as follows: AC>AB>BC, the interaction between ratio (A) and stirring temperature (B) and between ratio (A) and stirring time (C) is significant. The model distortion term P is 0.7064>0.05, no significance, i.e. no significant loss of similarity due to error, and R²＝0.9981，R² _Adj0.9956, all are close to 1, which shows that the model is reliable and can be used for the analysis and prediction of the preparation condition and the hemolysis rate of the composite scaffold material.

TABLE 3 analysis of variance of regression models

(3) Analysis of response surface for interaction between two factors

The interaction of the concentration ratio, the stirring temperature and the stirring time is analyzed, and a contour map and a three-dimensional map of the response surface of each factor to the hemolysis rate of the material are shown in figures 6-8. The response surface can directly reflect the influence degree of each experimental factor on the hemolysis rate of the material, and the steeper the gradient of the response surface is, the larger the influence of the experimental factor on the hemolysis rate of the material is. The contour map is the projection of the response surface on the bottom surface and can reflect the strength of the interaction between the two factors, and the elliptical contour map shows that the interaction between the two factors is obvious. The results in FIGS. 6-8 show that the response surface of the mixture ratio is steepest, the stirring time is second, and the stirring temperature is slowest, which indicates that the stirring temperature has no obvious influence on the hemolysis rate of the material. The interaction of the concentration ratio and the stirring time has the most obvious influence on the hemolysis rate of the material, the interaction of the concentration ratio and the stirring temperature is the second order, and the interaction of the stirring temperature and the stirring time has no obvious influence on the hemolysis rate of the material.

(4) Prediction and validation of optimal production conditions

Through Design Expert software analysis, the optimal process conditions for preparing the yak skin gelatin/PMVE-MA composite scaffold material are as follows: the ratio is 6.25:1 (yak skin glue 8% w/v, PMVE-MA 1.28% w/v), the stirring temperature is 40.84 ℃, the stirring time is 3.88h, and under the condition, the hemolysis rate theoretical value of the prepared composite material is 0.092%. According to the actual situation, the preparation conditions of the composite scaffold material are modified as follows: the optimal process is 6:1 (yak skin gelatin 8% w/v, PMVE-MA 1.33% w/v), the stirring temperature is 41 ℃, and the stirring time is 3.85 h.

Three groups of parallel verification experiments are carried out under the optimal preparation condition, the average value of the hemolysis rate of the material is 0.145 percent and is close to the model value, which shows that the model is real and reliable and can be used for predicting the preparation condition of the yak skin gel/PMVE-MA composite scaffold material.

3. Characterization of the Yak skin rubber/PMVE-MA composite scaffold

The composite scaffold material of example 1 was characterized by swelling degree, degradation rate, measurement of mechanical properties and observation of microstructure.

(1) Microstructure

The sample morphology is shown in fig. 9. FIGS. 9(a) and (b) are section SEM of pure yak skin gelatin material and yak skin gelatin/PMVE-MA composite scaffold material with the same magnification (scale: 300um), and it can be observed from the figure that the section gap of the pure yak skin gelatin material is less, the gap size distribution is more uniform, and the material is more compact; the section of the composite material is in a loose lamellar structure, contains more irregular gaps, has better swelling performance, and is beneficial to cell adhesion and growth, and the intercommunicated gap structure is beneficial to cell growth and proliferation.

(2) Degree of swelling

The swelling degree is an important characteristic of the scaffold material, and the good swelling property is beneficial to the adhesion and proliferation of cells on the scaffold material. Calculated by the following formula:

swelling degree [ (Ww-Wd)/Wd ] × 100%; ww refers to the mass of the wet scaffold after swelling with water, and Wd refers to the mass of the dry scaffold without water.

Fig. 10(a) shows the swelling degree changes of the composite scaffold material after being soaked in PBS solution for 1h, 3h, 5h, 10h, 12h, and 24h, which shows that the swelling degree of the material is rapidly increased within 1h of the beginning of soaking, and the swelling degree is slightly increased at subsequent time points, and after being soaked for 12h, the swelling degree tends to be stable without obvious increase trend, and the swelling degree at this time is the maximum swelling degree and is less than 100% (71.03%). The swelling performance of the stent material is related to the hydrophilicity of the polymer and the microstructure of the material, and the stent material shows better swelling performance because the PMVE-MA has good water retention. According to the observation result of SEM, compared with the pure yak skin glue material, the composite scaffold material has more gap structures, so that the swelling of the material can be further promoted; and Hemlata Chhabra^[1]Compared with the swelling degree (more than 400%) of the gelatin/PMVE-MA composite stent material prepared by the people, the swelling degree of the stent material in the research is obviously lower. There are research reports^[2]An excessively high swelling ratio means that an excessive amount of water enters the interior of the scaffold material, which may cause the scaffold material to generate an inside-out pressure, which may destroy the microstructure thereof, which may cause a decrease in mechanical properties, and may affect the adhesion behavior of cells on the scaffold material. Therefore, compared with the gelatin/PMVE-MA composite scaffold prepared by Hemlata Chhabra et al, the swelling behavior of the invention has obvious advantages.

(3) Degradation Properties

Fig. 10(b) is the mass loss rate of the composite scaffold material after being soaked in PBS solution for 1d, 3d, 5d, 7d and 10d at room temperature, showing the degradation degree of the composite scaffold material at different time points, as can be seen from the figure, the degradation rate of the material gradually increases with time, and the degradation rate reaches 16.44% at day 10, i.e. 73.56% of the scaffold material still exists after day 10, which satisfies the time requirement of the scaffold material being implanted into the body.

(4) Mechanical properties

The results of the mechanical property measurements of the scaffold material (dry state) are shown in table 4. The detection result shows that the bending strength of the yak skin rubber/PMVE-MA composite scaffold material is not much different from that of a pure yak skin rubber material, and the yak skin rubber/PMVE-MA composite scaffold material has approximate flexibility, which indicates that the polymer PMVE-MA has no obvious influence on the bending strength of the composite scaffold material; the composite scaffold material has the advantages that the compression strength and the compression modulus are obviously higher than those of a pure yak skin gum material, the composite scaffold material has stronger compressive capacity, and compared with the pure yak skin gum material, the composite scaffold material shows better mechanical property due to the enhancement effect of the reaction between the polymer and the yak skin gum, and is suitable for being applied as a scaffold material for tissue engineering.

In addition, the compressive modulus of the composite scaffold material prepared by the research is obviously higher than that of the gelatin/PMVE-MA composite scaffold material prepared by Hemlata Chhabra and the like (the dry compressive modulus is lower than 30MPa, and the wet compressive modulus is lower than 5MPa), which shows that the scaffold material prepared by the yak skin gelatin composite PMVE-MA has obvious advantages in the aspect of mechanical properties.

TABLE 4 mechanical Properties of the scaffold Material

n＝3)

Note: signifying the significance of the difference in compressive strength of the samples

P <0.05, significant difference; indicates P <0.01, with very significant difference

In conclusion, the yak skin gel/PMVE-MA composite material provided by the invention has excellent swelling degree and mechanical properties, the degradation rate can meet the time requirement of implanting the scaffold material into a body, the microstructure meets the condition of cell adhesion growth, and the yak skin gel/PMVE-MA composite material has low hemolysis rate and has excellent potential as a tissue engineering scaffold material.

Reference documents:

[1]Chhabra H,Gupta P,Verma PJ,et al.Gelatin–PMVE/MA composite scaffold promotes expansion of embryonic stem cells[J].Materials Science& Engineering C,2014,37.

[2] the preparation and characterization of the graphene oxide-sodium alginate-chitosan composite scaffold [ J ] Proc of higher school chemistry 2020,41(09): 2099-2106.

Claims (10)

1. A yak skin glue/PMVE-MA composite material is characterized in that the yak skin glue/PMVE-MA composite material is formed by compounding yak skin glue and PMVE-MA; the mass ratio of the yak hide glue to the PMVE-MA is (4-8): 1.

2. The composite material of claim 1, wherein the mass ratio of yak hide gelatin to PMVE-MA is 6: 1.

3. A composite material according to claim 1 or 2, characterized in that it has a haemolysis rate not higher than 5%, preferably between 0.1% and 1.6%.

4. The composite material according to claim 1 or 2, characterized in that it has a compression modulus of not less than 300MPa, preferably 391 to 468 MPa.

5. Composite material according to claim 1 or 2, characterized in that it has a maximum swelling capacity not higher than 100%, preferably between 54% and 72%.

6. A composite material as claimed in claim 1 or claim 2, which is prepared by blending yak skin gelatin and PMVE-MA in proportion, pre-freezing and freeze-drying the blend and then soaking the blend in HMDI solution.

7. The composite material of claim 6, wherein the blending is: mixing yak hide gelatin and PMVE-MA in proportion, and stirring at 37-55 ℃ for 1-4 hours; and/or the pre-freezing is: freezing at-50 deg.c to-100 deg.c; and/or the soaking is: soaking in HMDI solution for 1-3 hours; preferably, the HMDI solution has a mass concentration of 10%.

8. A method for preparing the composite material according to claims 1 to 7, characterized by comprising the steps of: mixing yak hide gelatin and PMVE-MA at a certain proportion, pre-freezing, freeze-drying, and soaking in HMDI solution.

9. The method of claim 9, comprising the steps of:

(1) mixing the ethanol solution of the yak skin gelatin and the ethanol solution of PMVE-MA in proportion;

(2) stirring for 2-3 hours at 37-55 ℃ to obtain a mixed solution;

(3) the mixed solution is pre-frozen at the temperature of between 50 ℃ below zero and 100 ℃ below zero and then is freeze-dried;

(4) and soaking the freeze-dried stent material in an HMDI solution for 1-3 hours.

10. Use of the composite material according to claims 1 to 7 in an in vivo implant material, preferably in a vascular stent material.

Images