Composite gel and preparation method thereof

Abstract

The invention provides a composite gel and a preparation method thereof, the composite gel is composed of 10%-30% of polyvinyl alcohol, 15%-25% of gelatin, 0.1%-1% of nano cerium oxide, 5%-15% of polyethylene glycol, 0.5%-2% of a cross-linking agent and deionized water, the nano cerium oxide is uniformly dispersed, the porosity of the gel is 20%-40%, and the water absorption rate is 300%-500%. The preparation method comprises the following steps: mixing polyvinyl alcohol, gelatin and water, heating and stirring to obtain a solution A; adding nano cerium oxide, and performing ultrasonic dispersion to obtain a solution B; adding polyethylene glycol and a cross-linking agent, and stirring to obtain a gel precursor; and treating and curing by two stages of electromagnetic fields with different intensities to obtain the gel. The porosity and the water absorption rate of the composite gel can be improved, and the controllability and the repeatability of the preparation process are improved.

Description

Technical Field

[0001] The present invention relates to the fields of material science and biomedical engineering, and more specifically, to a composite gel and a preparation method thereof. Background Art

[0002] In the field of materials science and biomedical engineering, gel materials have broad application prospects in many fields such as tissue engineering, drug release, and wound dressings due to their unique physical and chemical properties, such as good biocompatibility, adjustable mechanical properties, and excellent water absorption. Traditional gel materials are mainly composed of natural or synthetic polymers, such as gelatin and polyvinyl alcohol. Although these materials meet the application requirements to a certain extent, they still have some limitations in terms of mechanical properties, pore structure, and matching degree with biological tissues.

[0003] For example, some gel materials have low porosity, which limits cell migration and nutrient exchange; insufficient water absorption affects their application effect in a humid environment. In addition, the surface structure of traditional gel materials is relatively simple, lacking micro-nano structures that can promote cell adhesion and growth, which to a certain extent limits their development in high-end application fields such as tissue engineering. In terms of preparation methods, traditional gel preparation processes often have problems such as cumbersome steps and imprecise parameter control, resulting in unstable product quality and difficulty in meeting the needs of large-scale production and application.

[0004] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following problems or defects in the prior art: the porosity and water absorption rate of existing gel materials are difficult to reach the ideal range at the same time, which limits their comprehensive performance in the fields of biomedicine and so on; the surface lacks micro-nano structure, which is not conducive to cell adhesion and growth, affecting its effect in high-end applications such as tissue engineering; the preparation process is not sophisticated enough and the parameter control is not precise enough, resulting in unstable product quality and difficulty in meeting the requirements of large-scale production and application. Summary of the invention

[0005] The invention provides a composite gel and a preparation method thereof.

[0006] In the first aspect of the present invention, a composite gel is provided, the components of which are as follows in terms of weight percentage:

[0007] 10% to 30% of polyvinyl alcohol, 15% to 25% of gelatin, 0.1% to 1% of nano-cerium oxide, 5% to 15% of polyethylene glycol, 0.5% to 2% of a cross-linking agent, and the remainder being deionized water; the nano-cerium oxide mainly exists in the gel in a uniformly dispersed form, and the porosity of the composite gel is between 20% and 40%, and the water absorption rate is between 300% and 500%.

[0008] Furthermore, the surface of the composite gel has a micro-nano structure, and the size of the micro-nano structure is between 100nm and 500nm.

[0009] In a second aspect of the present invention, a method for preparing a composite gel is provided, which specifically comprises the following steps:

[0010] Step 1, polyvinyl alcohol, gelatin and deionized water are mixed according to a certain proportion, heated to 80° C. to 90° C., and stirred evenly to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A;

[0011] Step 2, adding nano-cerium oxide to the mixed solution A, and using ultrasonic dispersion for 30 minutes to 60 minutes to uniformly disperse the nano-cerium oxide in the solution to obtain a mixed solution B;

[0012] Step 3, adding polyethylene glycol to the mixed solution B, stirring evenly, then adding a crosslinking agent, and continuing to stir for 1 h to 2 h to allow the crosslinking agent to fully react with the components in the mixed solution to form a gel precursor;

[0013] Step 4, placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field strength to be 100 mT to 200 mT, and treating for 10 min to 20 min, so that the gel precursor is initially cross-linked;

[0014] Step 5, placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field strength to 200mT to 300mT, and the treatment time to 10min to 20min, so that the gel precursor is further cross-linked and cured to obtain the composite gel.

[0015] Furthermore, in step 1, the heating and stirring time is 2 h to 3 h, and the stirring speed is 100 r / min to 200 r / min.

[0016] Furthermore, in step 2, the frequency of ultrasonic dispersion is 20kHz to 40kHz, and the power is 100W to 300W.

[0017] Furthermore, in step 3, the cross-linking agent is glutaraldehyde, and its mass percentage is 0.5% to 1%; the stirring speed is 150 r / min to 250 r / min.

[0018] Furthermore, in step 4 and step 5, during the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20° C. to 40° C.

[0019] Furthermore, in step 1, the heating and stirring time is 2h to 3h, and the stirring speed is 100r / min to 200r / min; in step 2, the frequency of ultrasonic dispersion is 20kHz to 40kHz, and the power is 100W to 300W; in step 3, the cross-linking agent is glutaraldehyde, and its mass percentage is 0.5% to 1%; the stirring speed is 150r / min to 250r / min; in steps 4 and 5, during the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20°C to 40°C; the particle size of the nano-cerium oxide is 10nm to 50nm.

[0020] Further, when the content of nano cerium oxide is 0.1% to 0.3%, the content of polyvinyl alcohol is controlled within the range of 15% to 20%; when the content of nano cerium oxide is 0.3% to 0.5%, the content of polyvinyl alcohol is controlled within the range of 20% to 25%; when the content of nano cerium oxide is 0.5% to 1%, the content of polyvinyl alcohol is controlled within the range of 25% to 30%; and in step 4, the first electromagnetic field intensity B1 and the nano cerium oxide content CCeO2 have the following relationship:

[0021] B1=30mT×CCeO2+70mT;

[0022] In step 5, the second electromagnetic field intensity B2 and the nano-cerium oxide content CCeO2 have the following relationship:

[0023] B2 = 100mT × CCeO2 + 100mT.

[0024] Furthermore, the crosslinking degree D of the gel is related to the polyvinyl alcohol content CPVA and the crosslinker content Ccrosslinker

[0025] The following relationship exists: D = 0.8×CPVA + 1.2×Ccrosslinker.

[0026] According to the above embodiments of the present invention, at least the following beneficial effects are achieved: the porosity and water absorption range of the composite gel can enable the gel to have good water absorption and water retention while maintaining a certain structural strength, can provide a suitable growth environment for cells, promote cell migration and nutrient exchange, and is conducive to tissue repair and regeneration. The micro-nano structure on the surface of the composite gel can simulate the microenvironment of biological tissues, increase the contact area between cells and the gel surface, improve cell adhesion, promote cell growth and differentiation, and thus enhance the application effect of the gel in biomedical fields such as tissue engineering.

[0027] In terms of the preparation method, by precisely controlling the parameters of each step, such as the time and speed of heating and stirring, the frequency and power of ultrasonic dispersion, the type and content of the cross-linking agent, the intensity and time of the electromagnetic field treatment, etc., the nano-cerium oxide can be evenly dispersed in the gel, ensuring the uniformity and consistency of the gel, and improving the quality and performance stability of the gel. At the same time, the preparation method has clear steps, simple operation, and is easy to achieve large-scale production, providing strong technical support for the widespread application of composite gels. In addition, by adjusting the content of polyvinyl alcohol and nano-cerium oxide and the electromagnetic field intensity and other parameters, the performance of the gel can be further optimized to meet the personalized needs in different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, in which:

[0029] Figure 1 A schematic diagram of a process for preparing a composite gel provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0030] The principles and spirit of the present invention will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are provided only to enable those skilled in the art to better understand and implement the present invention, and are not intended to limit the scope of the present invention in any way. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. All features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive characteristics and / or steps, can be combined in any way, unless otherwise described, and can be replaced by other equivalent or alternative features with similar purposes, that is, unless otherwise described, each feature is only one embodiment in a series of equivalent or similar features.

[0032] In some embodiments, a composite gel comprises the following components in weight percentage: 10% to 30% polyvinyl alcohol, 15% to 25% gelatin, 0.1% to 1% nano-cerium oxide, 5% to 15% polyethylene glycol, 0.5% to 2% cross-linking agent, and the rest is deionized water; the nano-cerium oxide mainly exists in the gel in a uniformly dispersed form, and the porosity of the composite gel is between 20% and 40%, and the water absorption rate is between 300% and 500%.

[0033] It should be noted that the composite gel involved in the present invention is a material with specific components and performance characteristics. The components of the gel, measured by weight percentage, include 10% to 30% polyvinyl alcohol (PVA), 15% to 25% gelatin, 0.1% to 1% nano cerium oxide (CeO2), 5% to 15% polyethylene glycol (PEG), 0.5% to 2% cross-linking agent, and the rest is deionized water. The polyvinyl alcohol mentioned here is a water-soluble high molecular polymer with good film-forming properties and biocompatibility; gelatin is a protein extracted from animal skin, bones and other tissues, with good biocompatibility and biodegradability; nano cerium oxide is a nano material with special physical and chemical properties, which can improve the stability and biological activity of the gel; polyethylene glycol is a commonly used pharmaceutical excipient that can adjust the viscosity and fluidity of the gel; the cross-linking agent is used to form chemical bonds between polymer molecules in the gel to increase the strength and stability of the gel. The porosity of the composite gel is between 20% and 40%, and the water absorption rate is between 300% and 500%. These performance indicators make the gel have potential application value in the biomedical field.

[0034] Specifically, the content of polyvinyl alcohol is in the range of 10% to 30%, which can be adjusted according to different application requirements. For example, when a gel with higher strength needs to be prepared, the content of polyvinyl alcohol can be appropriately increased; when a softer gel needs to be prepared, its content can be reduced. The content of gelatin is between 15% and 25%, and this ratio range can ensure that the gel has good biocompatibility and certain mechanical properties. Although the content of nano-cerium oxide is only 0.1% to 1%, it plays a key modification role in the gel, and the performance of the gel can be optimized by adjusting its content. The content of polyethylene glycol is between 5% and 15%, which is mainly used to adjust the viscosity and fluidity of the gel to make it more suitable for different processing and application processes. The content of the cross-linking agent is between 0.5% and 2%, and this range can ensure that the gel has an appropriate degree of cross-linking, so as to obtain the required mechanical properties and stability. Porosity and water absorption are important indicators for measuring gel performance. A porosity between 20% and 40% can ensure that the gel has good air permeability and nutrient exchange capacity, while a water absorption between 300% and 500% enables the gel to maintain stable shape and performance in a humid environment.

[0035] Preferably, when preparing a composite gel for wound dressing, a polyvinyl alcohol content of 20%, a gelatin content of 20%, a nano-cerium oxide content of 0.5%, a polyethylene glycol content of 10%, a cross-linking agent content of 1%, and the rest of deionized water can be selected. Such a ratio can ensure that the gel has good biocompatibility and mechanical properties while having high water absorption and appropriate porosity, which is beneficial to wound healing. During the preparation process, the performance of the gel can be further optimized by controlling parameters such as the time and speed of heating and stirring, the frequency and power of ultrasonic dispersion. For example, in step 1, the time of heating and stirring can be set to 2.5 hours, and the stirring speed is 150r / min; in step 2, the frequency of ultrasonic dispersion can be set to 30kHz, and the power is 200W.

[0036] Furthermore, the surface of the gel can be treated as needed, such as by introducing a specific micro-nano structure on its surface by physical or chemical methods, so as to further improve the biocompatibility and cell adhesion of the gel.

[0037] In some embodiments, the surface of the composite gel has a micro-nano structure, and the size of the micro-nano structure is between 100 nm and 500 nm.

[0038] It should be noted that the composite gel surface mentioned in the present invention has a micro-nano structure, which means that there are microstructures with a size between 100nm and 500nm on the gel surface. This micro-nano structure can simulate the microenvironment of biological tissues and provide cells with growth conditions that are closer to natural tissues. In the biomedical field, the interaction between cells and materials depends to a large extent on the physicochemical properties of the material surface, and the micro-nano structure can increase the contact area between cells and materials, promote cell adhesion, proliferation and differentiation, thereby improving the biocompatibility and biological activity of the material.

[0039] Specifically, the size range of micro-nano structures is 100nm to 500nm and is carefully designed. Within this size range, the structure can effectively interact with receptors on the cell surface and simulate the microenvironment of the extracellular matrix. For example, the adhesion and migration of some cell types are very sensitive to surface roughness, and micro-nano structures of 100nm to 500nm can provide sufficient physical cues to guide cell behavior. In addition, micro-nano structures of this size can also affect the morphology and function of cells, such as promoting cell spreading and reorganization of the cytoskeleton, which is essential for cell growth and tissue regeneration.

[0040] Preferably, in order to realize the micro-nano structure on the surface of the composite gel, a specific surface treatment technology can be used in the preparation process. For example, after the gel is formed, micro-nano structures can be manufactured on its surface by laser etching, plasma treatment or chemical etching. Taking laser etching as an example, micro-nano processing of the gel surface can be achieved by precisely controlling the power, scanning speed and focus size of the laser. The specific parameter settings can be: the laser power is set between 50mW and 200mW, the scanning speed is 10mm / s to 50mm / s, and the focus size is about 100nm to 300nm.

[0041] Furthermore, a mold replication method can also be used, that is, a mold with the desired micro-nano structure is first made, and then the gel is formed in the mold during the gel preparation process, thereby replicating the gel surface with the same micro-nano structure. The advantage of this method is that composite gels with uniform micro-nano structures can be mass-produced, improving production efficiency and consistency of product quality.

[0042] In some embodiments, the preparation method of the composite gel is as follows: Figure 1 As shown, the following steps are included:

[0043] Step 1, polyvinyl alcohol, gelatin and deionized water are mixed according to a certain proportion, heated to 80° C. to 90° C., and stirred evenly to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A;

[0044] Step 2, adding nano-cerium oxide to the mixed solution A, and using ultrasonic dispersion for 30 minutes to 60 minutes to uniformly disperse the nano-cerium oxide in the solution to obtain a mixed solution B;

[0045] Step 3, adding polyethylene glycol to the mixed solution B, stirring evenly, then adding a crosslinking agent, and continuing to stir for 1 h to 2 h to allow the crosslinking agent to fully react with the components in the mixed solution to form a gel precursor;

[0046] Step 4, placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field strength to be 100 mT to 200 mT, and treating for 10 min to 20 min, so that the gel precursor is initially cross-linked;

[0047] Step 5, placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field strength to 200mT to 300mT, and the treatment time to 10min to 20min, so that the gel precursor is further cross-linked and cured to obtain the composite gel.

[0048] It should be noted that the composite gel preparation method provided by the present invention is a systematic process flow, which aims to prepare a composite gel with specific properties by precisely controlling the mixing, dispersion and cross-linking process of each component. The method covers multiple key steps from raw material mixing to final gel forming, ensuring the quality and performance consistency of the gel. In this process, a number of professional terms and operating steps are involved, for example, a cross-linking agent is a compound that can form chemical bonds between polymer chains, increasing the stability and strength of the gel; electromagnetic field treatment uses the physical effect of the electromagnetic field to promote the cross-linking reaction of the gel and optimize the structure and performance of the gel.

[0049] Specifically, the first step of the preparation method is to mix polyvinyl alcohol, gelatin and deionized water and heat and stir. The purpose of this step is to fully dissolve polyvinyl alcohol and gelatin to form a uniform mixed solution A. The heating temperature is controlled at 80°C to 90°C, the stirring time is set to 2h to 3h, and the stirring speed is 100r / min to 200r / min. These parameters are set to ensure that the polymer can be completely dissolved and to avoid undissolved particles affecting the uniformity and performance of the subsequent gel. In the second step, the addition of nano-cerium oxide and ultrasonic dispersion treatment are to make the nano-cerium oxide evenly distributed in the solution. The ultrasonic dispersion time is 30min to 60min, the frequency is 20kHz to 40kHz, and the power is 100W to 300W. The selection of these parameters helps to break the agglomeration of nanoparticles and achieve their uniform dispersion in the gel matrix. In the third step, the addition of polyethylene glycol and the use of a cross-linking agent are to construct a network structure of the gel. The mass percentage of the cross-linking agent glutaraldehyde is 0.5% to 1%, and the stirring speed is 150r / min to 250r / min. This step is essential for forming a gel with appropriate elasticity and strength. Finally, through two stages of electromagnetic field treatment, respectively controlled at different electromagnetic field intensities and times, the cross-linking and curing of the gel are further promoted to form the final composite gel product.

[0050] Preferably, in step 1, in order to ensure the complete dissolution of polyvinyl alcohol and gelatin, a gradual heating method can be adopted, first preheating at 70°C for 30 minutes, then heating to 85°C and continuing stirring for 2.5 hours, and the stirring speed can be set to 150r / min to achieve a better mixing effect. In step 2, in order to further optimize the dispersion effect of nano-cerium oxide, pulse ultrasonic dispersion technology can be used, that is, pausing for 1 minute every 5 minutes, the total dispersion time is 45 minutes, and the ultrasonic frequency and power are set to 30kHz and 200W respectively. In step 3, in addition to using glutaraldehyde as a cross-linking agent, it is also possible to consider adding a small amount of chitosan to enhance the biocompatibility and antibacterial properties of the gel, and the amount of chitosan added can be controlled at 0.1% to 0.5%. In the electromagnetic field treatment step, an alternating electromagnetic field intensity can be used, that is, in the first electromagnetic field treatment, the intensity is first treated with 150mT for 10 minutes, and then increased to 180mT for the remaining 10 minutes; in the second electromagnetic field treatment, the intensity is first treated with 250mT for 10 minutes, and then increased to 280mT for the remaining 10 minutes. This treatment method can promote the cross-linking of the gel more evenly and improve the uniformity and stability of the gel.

[0051] In some embodiments, in step 1, the heating and stirring time is 2 hours to 3 hours, and the stirring speed is 100 r / min to 200 r / min.

[0052] It should be noted that the composite gel preparation method mentioned in the present invention specifically stipulates the time and speed of heating and stirring in step 1. This provision is to ensure that polyvinyl alcohol and gelatin can be fully dissolved in deionized water to form a uniform mixed solution A. Heating and stirring is a commonly used method in chemical preparation. By providing sufficient heat and mechanical stirring, the dissolution process of the polymer can be accelerated and the uniformity of the solution can be improved. In the present invention, the setting of the stirring speed and time is to balance the dissolution efficiency and energy consumption, while avoiding changes in the properties of the solution caused by excessive stirring.

[0053] Specifically, the heating and stirring time is set to 2 to 3 hours. This time range is based on experimental data and experience, and is intended to ensure that polyvinyl alcohol and gelatin have enough time to completely dissolve. The stirring speed is set between 100 rpm and 200 rpm. This speed range can provide sufficient shear force to evenly disperse the polymer molecules in water while avoiding the introduction of too many bubbles due to excessive stirring speed, which affects the quality of the solution. Within this parameter range, appropriate adjustments can be made according to specific equipment and operating conditions to achieve the best dissolution effect.

[0054] Preferably, in step 1, a staged heating and stirring method can be adopted. For example, first stir at a speed of 100 revolutions per minute for 1 hour, then gradually increase the stirring speed to 150 revolutions per minute, continue stirring for 1 hour, and finally stir at a speed of 200 revolutions per minute for the remaining 1 hour. This staged stirring method can more effectively promote the dissolution of polyvinyl alcohol and gelatin, while reducing the impact on the solution caused by sudden changes in stirring speed.

[0055] Furthermore, in order to further improve the dissolution efficiency, the heating temperature can be appropriately adjusted during the stirring process. For example, the temperature can be controlled at 85°C in the first 1.5 hours of stirring, and then the temperature can be reduced to 80°C in the remaining 1.5 hours. Such temperature changes help the gradual dissolution of the polymer while reducing the polymer degradation that may be caused by long-term heating at high temperature.

[0056] In some embodiments, in step 2, the frequency of ultrasonic dispersion is 20kHz to 40kHz, and the power is 100W to 300W.

[0057] It should be noted that the ultrasonic dispersion technology mentioned in the present invention is a key step for ensuring that nano-cerium oxide is uniformly distributed in the mixed solution A. Ultrasonic dispersion is a method that uses the high-frequency vibration energy of ultrasound to break up particle agglomeration and achieve uniform dispersion of particles in a liquid. In the present invention, by accurately controlling the frequency and power of ultrasound, the agglomeration of nano-cerium oxide particles can be effectively prevented, thereby improving the performance and stability of the composite gel. The setting of the ultrasonic frequency and power is based on factors such as the characteristics of the nanoparticles and the viscosity of the solution to achieve the best dispersion effect.

[0058] Specifically, the frequency of ultrasonic dispersion is set between 20kHz and 40kHz. This frequency range can generate enough energy to overcome the van der Waals force between nano-cerium oxide particles and prevent particle agglomeration. The power is set between 100W and 300W. This power range can ensure the effective transmission of ultrasonic energy while avoiding damage to other components in the solution due to excessive power. Within this parameter range, appropriate adjustments can be made according to specific experimental conditions and equipment performance to achieve the best dispersion effect. For example, for a nano-cerium oxide solution with a higher concentration, it may be necessary to select a higher ultrasonic power and a longer dispersion time to achieve uniform dispersion.

[0059] Preferably, in step 2, an intermittent ultrasonic dispersion method can be used. For example, ultrasonic dispersion is performed for 10 minutes, and then paused for 5 minutes, for a total of 6 cycles, so that local overheating and changes in solution properties that may be caused by long-term continuous ultrasound can be avoided. At the same time, in order to further improve the dispersion effect, an appropriate amount of dispersant, such as polyvinyl pyrrolidone (PVP), can be added during the ultrasonic dispersion process, and the amount added can be controlled at 0.1% to 0.5% (weight percentage) to enhance the surface charge of the nano-cerium oxide particles and further prevent particle agglomeration.

[0060] Furthermore, the frequency and power of ultrasound can be appropriately adjusted according to experimental needs. For example, a higher frequency (such as 40kHz) and a lower power (such as 150W) can be used in the first 30 minutes of dispersion, and a lower frequency (such as 20kHz) and a higher power (such as 250W) can be used in the last 30 minutes to achieve effective dispersion of nano-cerium oxide particles of different particle sizes.

[0061] In some embodiments, in step 3, the cross-linking agent is glutaraldehyde, and its mass percentage is 0.5% to 1%; the stirring speed is 150 r / min to 250 r / min.

[0062] It should be noted that the cross-linking agent mentioned in the present invention is glutaraldehyde, and its mass percentage is 0.5% to 1%. The cross-linking agent plays a vital role in the preparation process of the composite gel. It can react chemically with the active groups on the polymer chain to form a cross-linked network structure, thereby giving the gel a certain shape and mechanical properties. Glutaraldehyde is a commonly used cross-linking agent with the advantages of high reactivity and good cross-linking effect. By controlling the amount of glutaraldehyde, the cross-linking degree of the gel can be adjusted, thereby affecting the hardness, elasticity and stability of the gel.

[0063] Specifically, the stirring speed is set between 150r / min and 250r / min. This speed range can ensure that the crosslinker fully contacts and reacts with other components in the mixed solution, while avoiding the introduction of too many bubbles due to excessive stirring speed, which affects the quality of the gel. Within this parameter range, appropriate adjustments can be made according to specific experimental conditions and equipment performance to achieve the best crosslinking effect. For example, for a reaction system with a larger volume, a higher stirring speed may be required to ensure mixing uniformity; for a reaction system with a smaller volume, a lower stirring speed may be selected to reduce energy consumption.

[0064] Preferably, in step 3, a method of gradually adding the crosslinking agent can be adopted. For example, half of the glutaraldehyde is first added to the mixed solution B, stirred for 30 minutes, and then the remaining half of the glutaraldehyde is added, and stirring is continued for 30 minutes. This gradual addition method can distribute the crosslinking agent more evenly, avoid excessive or low local crosslinking, and thus improve the quality and performance consistency of the gel.

[0065] Furthermore, in order to further improve the cross-linking effect, the temperature can be appropriately adjusted during the stirring process. For example, the temperature can be controlled at 25°C in the first hour of stirring, and then the temperature can be increased to 35°C in the remaining hour. Such temperature changes help accelerate the cross-linking reaction while reducing polymer degradation that may be caused by long-term high-temperature treatment.

[0066] In some embodiments, in step 4 and step 5, during the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20° C. to 40° C.

[0067] It should be noted that the electromagnetic field treatment process mentioned in the present invention is a key step in the composite gel preparation method, which aims to promote the cross-linking reaction of the gel precursor through the action of an external electromagnetic field, thereby forming a composite gel with a specific structure and performance. Electromagnetic field treatment involves two stages, which are carried out under different electromagnetic field intensities. This process has a decisive influence on the final performance of the gel. The electromagnetic field intensity refers to the magnitude of the electromagnetic force per unit area, which determines the intensity of the electromagnetic field on the gel precursor; the treatment time refers to the length of time the gel precursor is exposed to the electromagnetic field. These two parameters jointly determine the depth and uniformity of the cross-linking reaction.

[0068] Specifically, in step 4, the first electromagnetic field intensity is controlled at 100mT to 200mT, and the treatment time is 10min to 20min. This parameter setting is to allow the gel precursor to initially form a cross-linked network, laying the foundation for subsequent further cross-linking. In step 5, the second electromagnetic field intensity is increased to 200mT to 300mT, and the treatment time is also 10min to 20min. The purpose is to further strengthen the degree of cross-linking on the basis of the existing preliminary cross-linked network and make the gel structure more stable. During the electromagnetic field treatment process, it is very important to keep the temperature of the gel precursor between 20℃ and 40℃, because the temperature will affect the rate of the cross-linking reaction and the final performance of the gel. This temperature range can not only ensure the smooth progress of the cross-linking reaction, but also avoid the destruction of the gel structure or the degradation of performance due to excessively high temperature.

[0069] Preferably, in step 4 and step 5, a temperature gradient electromagnetic field treatment method can be used. For example, in step 4, the electromagnetic field intensity is first treated for 10 minutes at 100mT, while the temperature of the gel precursor is gradually increased from 20°C to 30°C; then the electromagnetic field intensity is increased to 150mT, and the treatment is continued for 10 minutes, while the temperature is maintained at 30°C. In step 5, the electromagnetic field intensity is first treated for 10 minutes at 200mT, and the temperature is gradually increased from 30°C to 35°C; then the electromagnetic field intensity is increased to 250mT, and the temperature is maintained at 35°C for the remaining 10 minutes. This temperature gradient treatment method can promote the cross-linking reaction more evenly and avoid uneven gel properties caused by excessively high or low local temperatures.

[0070] Furthermore, in order to further optimize the electromagnetic field treatment effect, the temperature of the gel precursor and the electromagnetic field intensity can be monitored in real time during the treatment process, and the parameters can be automatically adjusted through a feedback control system to ensure the accuracy and consistency of the treatment process.

[0071] In some embodiments, in step 1, the heating and stirring time is 2h to 3h, and the stirring speed is 100r / min to 200r / min; in step 2, the frequency of ultrasonic dispersion is 20kHz to 40kHz, and the power is 100W to 300W; in step 3, the cross-linking agent is glutaraldehyde, and its mass percentage is 0.5% to 1%; the stirring speed is 150r / min to 250r / min; in steps 4 and 5, during the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20°C to 40°C; the particle size of the nano-cerium oxide is 10nm to 50nm.

[0072] It should be noted that the preparation method of the composite gel mentioned in the present invention combines multiple key steps and precise control of parameters to ensure the quality and performance of the gel. This includes multiple links such as heating and stirring, ultrasonic dispersion, crosslinking agent addition, electromagnetic field treatment, etc., and each link has its specific parameter settings. In addition, the particle size range of nano-cerium oxide is also specifically pointed out, because the particle size of the nanomaterial will directly affect its dispersibility in the gel and the performance of the final gel. Nano-cerium oxide with a particle size between 10nm and 50nm can be better dispersed in the gel matrix, thereby improving the stability and biocompatibility of the gel.

[0073] Specifically, the heating and stirring time is set to 2 hours to 3 hours, and the stirring speed is 100r / min to 200r / min. Such parameter settings are to ensure that polyvinyl alcohol and gelatin can be fully dissolved to form a uniform mixed solution. The frequency of ultrasonic dispersion is set between 20kHz and 40kHz, and the power is 100W to 300W, which helps to evenly disperse nano-cerium oxide in the solution. The mass percentage of the cross-linking agent glutaraldehyde is controlled at 0.5% to 1%, and the stirring speed is 150r / min to 250r / min, which helps to form a uniform cross-linked network. During the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20°C to 40°C, which helps to control the speed and uniformity of the cross-linking reaction. The particle size of nano-cerium oxide is controlled at 10nm to 50nm, which helps to improve its dispersibility in the gel, thereby improving the performance of the gel.

[0074] Preferably, in step 1, a strategy of gradually increasing the temperature and stirring speed can be adopted. For example, the initial temperature is set to 70°C and the stirring speed is 100r / min. As time goes by, the temperature is gradually raised to 85°C, the stirring speed is raised to 150r / min, and finally maintained at 90°C and 200r / min until the mixture is completely dissolved. In step 2, the ultrasonic dispersion can be in a pulse mode, that is, every 30 minutes of dispersion, pause for 10 minutes to avoid the effect of overheating on the properties of nano-cerium oxide and solution. In step 3, the addition of the crosslinking agent can be carried out twice, and each addition is fully stirred for 30 minutes to ensure the uniformity of the crosslinking reaction. In the electromagnetic field treatment step, a method of gradually increasing the electromagnetic field intensity can be adopted, for example, in step 4, starting from 100mT, increasing by 10mT every 5 minutes until reaching 200mT; in step 5, starting from 200mT, increasing by 10mT every 5 minutes until reaching 300mT, while maintaining the temperature between 30°C and 35°C to optimize the crosslinking effect.

[0075] In some embodiments, when the content of nano cerium oxide is 0.1% to 0.3%, the content of polyvinyl alcohol is controlled within the range of 15% to 20%; when the content of nano cerium oxide is 0.3% to 0.5%, the content of polyvinyl alcohol is controlled within the range of 20% to 25%; when the content of nano cerium oxide is 0.5% to 1%, the content of polyvinyl alcohol is controlled within the range of 25% to 30%; and in step 4, the first electromagnetic field intensity B1 and the nano cerium oxide content CCeO2 have the following relationship:

[0076] B1=30mT×CCeO2+70mT;

[0077] In step 5, the second electromagnetic field intensity B2 and the nano-cerium oxide content CCeO2 have the following relationship:

[0078] B2 = 100mT × CCeO2 + 100mT.

[0079] It should be noted that the preparation method of the composite gel mentioned in the present invention further refines the content relationship between polyvinyl alcohol and nano-cerium oxide, as well as the relationship between the electromagnetic field intensity and the nano-cerium oxide content. This refinement is to more accurately control the performance of the gel so that it can better adapt to different application requirements. The adjustment of the polyvinyl alcohol content is based on the change in the nano-cerium oxide content to ensure the mechanical properties and stability of the gel. The adjustment of the electromagnetic field intensity is to optimize the cross-linking process to make the structure of the gel more uniform and stable. Through this precise parameter control, a composite gel with specific properties can be prepared to meet the requirements of different application scenarios.

[0080] Specifically, when the content of nano cerium oxide is between 0.1% and 0.3%, the content of polyvinyl alcohol is controlled within the range of 15% to 20%; when the content of nano cerium oxide is between 0.3% and 0.5%, the content of polyvinyl alcohol is controlled within the range of 20% to 25%; when the content of nano cerium oxide is between 0.5% and 1%, the content of polyvinyl alcohol is controlled within the range of 25% to 30%. This content relationship is set based on experimental data and theoretical analysis, aiming to balance the elasticity and strength of the gel by adjusting the content of polyvinyl alcohol, while ensuring that nano cerium oxide can be evenly dispersed in the gel matrix. In the electromagnetic field treatment step, the relationship between the first electromagnetic field intensity B1 and the nano cerium oxide content CCEO2 is B1=30mT×CCeO2+70mT, and the relationship between the second electromagnetic field intensity B2 and the nano cerium oxide content CCEO2 is B2=100mT×CCeO2+100mT. These formulas provide an accurate method for calculating the electromagnetic field intensity to ensure that the cross-linking reaction can be carried out under optimal conditions, thereby obtaining a composite gel with excellent performance.

[0081] Preferably, during the preparation process, the above parameters can be fine-tuned according to specific experimental conditions and equipment performance. For example, in step 4, if the electromagnetic field intensity output of the experimental equipment is not stable enough, the processing time can be appropriately increased to ensure that the cross-linking reaction is fully carried out. In step 5, if it is found that the degree of curing of the gel is insufficient, the electromagnetic field intensity can be appropriately increased or the processing time can be extended.

[0082] Furthermore, in order to further improve the performance of the gel, an appropriate amount of plasticizer or antioxidant can be added during the preparation process to improve the flexibility and stability of the gel. For example, adding 0.1% to 0.5% of a plasticizer, such as dibutyl phthalate, can improve the flexibility of the gel; adding 0.05% to 0.2% of an antioxidant, such as vitamin E, can improve the antioxidant properties of the gel and extend its service life.

[0083] In some embodiments, the crosslinking degree D of the gel is related to the polyvinyl alcohol content CPVA, the crosslinker content Ccrosslinker

[0084] The following relationship exists: D = 0.8×CPVA + 1.2×Ccrosslinker.

[0085] It should be noted that the preparation method of the composite gel mentioned in the present invention further refines the calculation formula of the crosslinking degree of the gel, that is, the crosslinking degree D of the gel and the polyvinyl alcohol content CPVA and the crosslinker content Ccrosslinker have the following relationship: D = 0.8 × CPVA + 1.2 × Ccrosslinker. This formula provides a theoretical basis for accurately controlling the crosslinking degree of the gel, so that the prepared gel can have the expected mechanical properties and stability. The crosslinking degree refers to the number and degree of chemical bonds formed between polymer chains in the gel, which directly affects the hardness, elasticity and stability of the gel. By adjusting the content of polyvinyl alcohol and the crosslinker, the crosslinking degree of the gel can be accurately controlled, thereby optimizing the performance of the gel and making it better adapted to different application requirements.

[0086] Specifically, the polyvinyl alcohol content CPVA and the crosslinker content Ccrosslinker are two key factors affecting the crosslinking degree of the gel. The polyvinyl alcohol content CPVA ranges from 10% to 30%, and the crosslinker content Ccrosslinker ranges from 0.5% to 2%. Through the above formula, the values ​​of these two parameters can be adjusted according to the required crosslinking degree D. For example, if you need to prepare a gel with a higher degree of crosslinking, you can appropriately increase the content of polyvinyl alcohol and crosslinker; conversely, if you need to prepare a gel with a lower degree of crosslinking, you can appropriately reduce the content of these two components. In addition, the calculation formula for the degree of crosslinking can also be used to predict and optimize the performance of the gel. By experimentally measuring the mechanical properties of the gel at different degrees of crosslinking, a relationship model between the degree of crosslinking and the performance can be established to provide guidance for the design and preparation of the gel.

[0087] Preferably, during the preparation process, the degree of crosslinking can be precisely controlled according to the specific experimental purpose and application requirements. For example, for gels that require higher elasticity and toughness, the degree of crosslinking can be controlled at a medium level by adjusting the content of polyvinyl alcohol and crosslinking agent.

[0088] More specifically, the polyvinyl alcohol content can be selected to be 20%, the crosslinking agent content can be selected to be 1%, and the crosslinking degree D calculated according to the formula is 0.8×20%+1.2×1%=17.2%. In actual operation, the accuracy of the crosslinking degree can be ensured by accurately weighing and mixing these components.

[0089] Furthermore, in order to further improve the performance of the gel, an appropriate amount of filler or reinforcing agent, such as nano-silicon dioxide or carbon nanotubes, can be added during the preparation process to improve the mechanical properties and stability of the gel. For example, adding 0.5% to 2% nano-silicon dioxide can improve the hardness and wear resistance of the gel.

[0090] Example 1

[0091] In this embodiment, the components of the composite gel are as follows by weight: 20% polyvinyl alcohol, 20% gelatin, 0.5% nano-cerium oxide, 10% polyethylene glycol, 0.8% cross-linking agent glutaraldehyde, and the rest is deionized water. The porosity of the composite gel is about 30%, and the water absorption rate is about 400%.

[0092] The preparation method of the composite gel is as follows:

[0093] Step 1, weighing 200 g of polyvinyl alcohol, 200 g of gelatin, 5 g of nano-cerium oxide, 100 g of polyethylene glycol, and 8 g of cross-linking agent glutaraldehyde;

[0094] Step 2: Add 497 g of deionized water to a 2000 ml beaker, heat to 85° C., add 200 g of polyvinyl alcohol and 200 g of gelatin, stir evenly for 2.5 hours at a stirring speed of 150 r / min to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A;

[0095] Step 3, adding 5 g of nano-cerium oxide to the mixed solution A, and using ultrasonic dispersion for 45 minutes, with an ultrasonic frequency of 30 kHz and a power of 200 W, to uniformly disperse the nano-cerium oxide in the solution, to obtain a mixed solution B;

[0096] Step 4, adding 100 g of polyethylene glycol to the mixed solution B, stirring evenly at a stirring speed of 200 r / min, then adding 8 g of cross-linking agent glutaraldehyde, and continuing to stir for 1.5 hours to allow the cross-linking agent to fully react with the components in the mixed solution to form a gel precursor;

[0097] Step 5, placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field intensity to be 150 mT, and treating for 15 minutes, so as to initially cross-link the gel precursor;

[0098] Step 6: placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field intensity to 250 mT, and treating for 15 minutes, so that the gel precursor is further cross-linked and cured to obtain the composite gel.

[0099] Experimental data:

[0100] Synthesis method: Follow steps 1 to 6 above.

[0101] Reaction conditions: heating and stirring temperature 85°C, time 2.5 hours, stirring speed 150r / min; ultrasonic dispersion frequency 30kHz, power 200W, time 45 minutes; stirring speed 200r / min, cross-linking agent glutaraldehyde content 0.8%, stirring time 1.5 hours; first electromagnetic field intensity 150mT, treatment time 15 minutes; second electromagnetic field intensity 250mT, treatment time 15 minutes.

[0102] Yield: The theoretical yield is 100%, and the actual yield is 97%.

[0103] Performance test: Through scanning electron microscope (SEM) analysis, the porosity of the gel is about 30%, and the water absorption rate is about 400%. Through mechanical property test, the compressive strength of the gel is 0.5MPa and the elastic modulus is 0.1MPa.

[0104] Uses and effects: This composite gel is suitable for biomedical materials, such as tissue engineering scaffolds, drug sustained-release carriers, etc. Experiments show that the gel has good biocompatibility and mechanical properties, can support cell growth and proliferation, and promote tissue repair and regeneration. In particular, the micro-nano structure on the surface significantly improves the adhesion and growth activity of cells, which helps to accelerate wound healing and tissue regeneration.

[0105] Example 2

[0106] In this embodiment, the components of the composite gel are as follows: 20% polyvinyl alcohol, 20% gelatin, 0.5% nano cerium oxide, 10% polyethylene glycol, 0.8% cross-linking agent glutaraldehyde, and the rest is deionized water. The composite gel has a porosity of about 30%, a water absorption rate of about 400%, and a micro-nano structure on the surface with a size between 100nm and 500nm.

[0107] The preparation method of the composite gel is as follows:

[0108] Step 1, weighing 200 g of polyvinyl alcohol, 200 g of gelatin, 5 g of nano-cerium oxide, 100 g of polyethylene glycol, and 8 g of cross-linking agent glutaraldehyde;

[0109] Step 2: Add 497 g of deionized water to a 2000 ml beaker, heat to 85° C., add 200 g of polyvinyl alcohol and 200 g of gelatin, stir evenly for 2.5 hours at a stirring speed of 150 r / min to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A;

[0110] Step 3, adding 5 g of nano-cerium oxide to the mixed solution A, and using ultrasonic dispersion for 45 minutes, with an ultrasonic frequency of 30 kHz and a power of 200 W, to uniformly disperse the nano-cerium oxide in the solution, to obtain a mixed solution B;

[0111] Step 4, adding 100 g of polyethylene glycol to the mixed solution B, stirring evenly at a stirring speed of 200 r / min, then adding 8 g of cross-linking agent glutaraldehyde, and continuing to stir for 1.5 hours to allow the cross-linking agent to fully react with the components in the mixed solution to form a gel precursor;

[0112] Step 5, placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field intensity to be 150 mT, and treating for 15 minutes, so as to initially cross-link the gel precursor;

[0113] Step 6, placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field intensity to 250 mT, and treating for 15 minutes, so that the gel precursor is further cross-linked and cured to obtain the composite gel;

[0114] Step 7: The cured composite gel is surface treated by using laser etching technology to manufacture micro-nano structures on its surface. The laser power is set to 150 mW, the scanning speed is 30 mm / s, the focus size is about 200 nm, and the processing time is 30 minutes.

[0115] Experimental data:

[0116] Synthesis method: Follow steps 1 to 7 above.

[0117] Reaction conditions: heating and stirring temperature 85°C, time 2.5 hours, stirring speed 150r / min; ultrasonic dispersion frequency 30kHz, power 200W, time 45 minutes; stirring speed 200r / min, cross-linking agent glutaraldehyde content 0.8%, stirring time 1.5 hours; first electromagnetic field intensity 150mT, treatment time 15 minutes; second electromagnetic field intensity 250mT, treatment time 15 minutes; laser etching power 150mW, scanning speed 30mm / s, focusing size 200nm, treatment time 30 minutes.

[0118] Yield: The theoretical yield is 100%, and the actual yield is 97%.

[0119] Performance test: Through scanning electron microscopy (SEM) analysis, the porosity of the gel is about 30%, and the water absorption rate is about 400%. The size of the micro-nano structure on the surface of the gel is between 100nm and 500nm. Through mechanical property testing, the compressive strength of the gel is 0.5MPa and the elastic modulus is 0.1MPa.

[0120] Uses and effects: This composite gel is suitable for biomedical materials, such as tissue engineering scaffolds, drug sustained-release carriers, etc. Experiments show that the gel has good biocompatibility and mechanical properties, can support cell growth and proliferation, and promote tissue repair and regeneration. In particular, the micro-nano structure on the surface significantly improves the adhesion and growth activity of cells, which helps to accelerate wound healing and tissue regeneration.

[0121] Comparative Example 1

[0122] The comparative example is a composite gel, which is made of the following raw materials in percentage by weight: 25% polyvinyl alcohol, 15% gelatin, 0.1% nano cerium oxide, 5% polyethylene glycol, 0.5% cross-linking agent glutaraldehyde, and the rest is deionized water.

[0123] The preparation method of the composite gel comprises the following steps:

[0124] S1. The polyvinyl alcohol, gelatin and deionized water were mixed in proportion, heated to 90°C, and stirred evenly for 3 hours at a stirring speed of 200 r / min to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A;

[0125] S2. The nano-cerium oxide was added to the mixed solution A and dispersed by ultrasonic wave for 30 minutes at an ultrasonic frequency of 20kHz and a power of 100W to uniformly disperse the nano-cerium oxide in the solution to obtain a mixed solution B;

[0126] S3. The polyethylene glycol was added to the mixed solution B, stirred evenly at a stirring speed of 100 r / min, and then the crosslinking agent glutaraldehyde was added, and stirring was continued for 2 hours to allow the crosslinking agent to fully react with the components in the mixed solution to form a gel precursor;

[0127] S4. placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field strength to 100 mT, and treating for 10 minutes to initially crosslink the gel precursor;

[0128] S5. placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field intensity to 200 mT, and treating for 10 minutes, so that the gel precursor is further cross-linked and cured to obtain the composite gel.

[0129] Comparative Example 2

[0130] The comparative example is a composite gel, which is made of the following raw materials in percentage by weight: 10% polyvinyl alcohol, 25% gelatin, 1% nano cerium oxide, 15% polyethylene glycol, 2% cross-linking agent glutaraldehyde, and the rest is deionized water.

[0131] The preparation method of the composite gel comprises the following steps:

[0132] S1. The polyvinyl alcohol, gelatin and deionized water were mixed in proportion, heated to 80°C, and stirred evenly for 2 hours at a stirring speed of 100 r / min to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A;

[0133] S2. The nano-cerium oxide was added to the mixed solution A and dispersed by ultrasonic for 60 minutes at an ultrasonic frequency of 40kHz and a power of 300W to uniformly disperse the nano-cerium oxide in the solution to obtain a mixed solution B;

[0134] S3. The polyethylene glycol was added to the mixed solution B, stirred evenly at a stirring speed of 150 r / min, and then the crosslinking agent glutaraldehyde was added, and stirring was continued for 1 hour to allow the crosslinking agent to react with the components in the mixed solution to form a gel precursor;

[0135] S4. placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field strength to 200 mT, and treating for 20 minutes to initially crosslink the gel precursor;

[0136] S5. placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field intensity to 300 mT, and treating for 20 minutes, so that the gel precursor is further cross-linked and cured to obtain the composite gel.

[0137] Experimental example

[0138] The composite gels prepared in Example 9 and Comparative Examples 1-2 were obtained respectively;

[0139] The composite gel was used to perform performance tests, and the test items included porosity, water absorption, compressive strength and elastic modulus; wherein, a total of 30 samples of the composite gel of Example 9 were tested, a total of 20 samples of the composite gel of Comparative Example 1 were tested, and a total of 25 samples of the composite gel of Comparative Example 2 were tested;

[0140] Test method:

[0141] The porosity and water absorption were analyzed by scanning electron microscopy (SEM); the compressive strength and elastic modulus were measured by mechanical properties tester;

[0142] The performance test results are shown in Tables 1 to 4:

[0143] Table 1 Statistics of porosity test results

[0144] Group Average porosity (%) Standard Deviation Example 9 30 ±2 Comparative Example 1 25 ±3 Comparative Example 2 35 ±4

[0145] Table 2 Statistics of water absorption test results

[0146] Group Average water absorption (%) Standard Deviation Example 9 400 ±30 Comparative Example 1 350 ±40 Comparative Example 2 450 ±50

[0147] Table 3 Compressive strength test results statistics

[0148] Group Average compressive strength (MPa) Standard Deviation Example 9 0.5 ±0.05 Comparative Example 1 0.4 ±0.06 Comparative Example 2 0.6 ±0.07

[0149] Table 4 Statistics of elastic modulus test results

[0150] Group Average elastic modulus (MPa) Standard Deviation Example 9 0.1 ±0.01 Comparative Example 1 0.08 ±0.01 Comparative Example 2 0.12 ±0.02

[0151] From Tables 1 to 4, we can see that:

[0152] The composite gels prepared by the technical scheme of the present application and the comparative example have certain porosity, water absorption, compressive strength and elastic modulus. Compared with the comparative example, the composite gel prepared by the technical scheme of the present application has a better balance in porosity and water absorption, and also shows better performance in compressive strength and elastic modulus, indicating that it has better comprehensive performance and is more suitable for use in fields such as biomedical materials.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0154] The above descriptions are only some preferred embodiments of the present invention and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present invention is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the embodiments of the present invention to form a technical solution.

Claims

1. A composite gel, characterized in that: The components of the composite gel are as follows by weight percentage: 10% to 30% polyvinyl alcohol, 15% to 25% gelatin, 0.1% to 1% nano cerium oxide, 5% to 15% polyethylene glycol, 0.5% to 2% cross-linking agent, and the rest is deionized water; the nano cerium oxide mainly exists in the gel in a uniformly dispersed form, and the porosity of the composite gel is between 20% and 40%, and the water absorption rate is between 300% and 500%.

2. The composite gel according to claim 1, characterized in that The surface of the composite gel has a micro-nano structure, and the size of the micro-nano structure is between 100nm and 500nm.

3. A method for preparing a composite gel, characterized in that: For preparing the composite gel according to claim 1 or 2, the preparation method comprises the following steps: Step 1, polyvinyl alcohol, gelatin and deionized water are mixed according to a certain proportion, heated to 80° C. to 90° C., and stirred evenly to completely dissolve the polyvinyl alcohol and gelatin to obtain a mixed solution A; Step 2, adding nano-cerium oxide to the mixed solution A, and using ultrasonic dispersion for 30 minutes to 60 minutes to uniformly disperse the nano-cerium oxide in the solution to obtain a mixed solution B; Step 3, adding polyethylene glycol to the mixed solution B, stirring evenly, then adding a crosslinking agent, and continuing to stir for 1 h to 2 h to allow the crosslinking agent to fully react with the components in the mixed solution to form a gel precursor; Step 4, placing the gel precursor in a first electromagnetic field, controlling the first electromagnetic field strength to be 100 mT to 200 mT, and treating for 10 min to 20 min, so that the gel precursor is initially cross-linked; Step 5, placing the gel precursor treated by the first electromagnetic field in a second electromagnetic field, controlling the second electromagnetic field strength to 200mT to 300mT, and the treatment time to 10min to 20min, so that the gel precursor is further cross-linked and cured to obtain the composite gel.

4. The method for preparing the composite gel according to claim 3, characterized in that: In the step 1, the heating and stirring time is 2 h to 3 h, and the stirring speed is 100 r / min to 200 r / min.

5. The method for preparing the composite gel according to claim 3, characterized in that: In the step 2, the frequency of ultrasonic dispersion is 20kHz to 40kHz, and the power is 100W to 300W.

6. The method for preparing the composite gel according to claim 3, characterized in that: In step 3, the cross-linking agent is glutaraldehyde, and its mass percentage is 0.5% to 1%; the stirring speed is 150 r / min to 250 r / min.

7. The method for preparing the composite gel according to claim 3, characterized in that: In step 4 and step 5, during the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20° C. to 40° C.

8. The method for preparing the composite gel according to claim 3, characterized in that: In the step 1, the heating and stirring time is 2h to 3h, and the stirring speed is 100r / min to 200r / min; in the step 2, the frequency of ultrasonic dispersion is 20kHz to 40kHz, and the power is 100W to 300W; in the step 3, the cross-linking agent is glutaraldehyde, and its mass percentage is 0.5% to 1%; the stirring speed is 150r / min to 250r / min; in the steps 4 and 5, during the electromagnetic field treatment, the temperature of the gel precursor is maintained at 20°C to 40°C; the particle size of the nano-cerium oxide is 10nm to 50nm.

9. The method for preparing the composite gel according to claim 8, characterized in that: When the content of nano cerium oxide is 0.1% to 0.3%, the content of polyvinyl alcohol is controlled within the range of 15% to 20%; when the content of nano cerium oxide is 0.3% to 0.5%, the content of polyvinyl alcohol is controlled within the range of 20% to 25%; when the content of nano cerium oxide is 0.5% to 1%, the content of polyvinyl alcohol is controlled within the range of 25% to 30%; and in step 4, the first electromagnetic field intensity B1 and the nano cerium oxide content CCeO2 have the following relationship: B1=30mT×CCeO2+70mT; In step 5, the second electromagnetic field intensity B2 and the nano-cerium oxide content CCeO2 have the following relationship: B2 = 100mT × CCeO2 + 100mT.

10. The method for preparing the composite gel according to claim 9, characterized in that: The crosslinking degree D of the gel is related to the content of polyvinyl alcohol CPVA and the content of crosslinker Ccrosslinker The following relationship exists: D = 0.8×CPVA + 1.2×Ccrosslinker.

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