Shape memory glucose-based aerogel and its preparation method and application
Through the reaction of dextran particles and sugar enzymes in buffered saline solution and supercritical dehydration technology, shape memory glucosyl aerogel was prepared, solving the problems of high waste liquid treatment cost and humidity sensitivity in starch aerogel preparation. , achieving green and efficient preparation and broadening application fields.
Patent Information
- Application Number
- CN202211104272.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-09
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2042-09-09
AI Technical Summary
The existing starch aerogel preparation process requires a high concentration of alkaline solution, which leads to high cost and unenvironmental treatment of waste liquids. Natural starch is sensitive to humidity, resulting in pore collapse, limiting its high-performance application.
Dextran particles react with sugar enzymes through buffered saline solution to form a mixed solution, and then dehydrate under supercritical conditions to prepare a shape memory glucosyl aerogel with low density and high porosity, with over 90% swelling. Water absorption and shape memory function.
It has achieved green and efficient preparation of shape memory glucosyl aerogels, expanded the application field of starch resources, and has porous, ultra-low density, high swelling moisture content properties, and is suitable for delivery and controlled release carriers, food packaging, and biomedical materials.
Smart Images
Figure CN116239815B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a shape memory glucose-based aerogel and a preparation method and application thereof, belonging to the technical field of starch deep processing. Background Art
[0002] Aerogel is a solid material composed of nano-scale colloidal particles aggregated to form a nanoporous grid structure, and the gaps are filled with gaseous dispersion medium. As a material with unique properties, aerogel has a wide range of application prospects due to its porous, ultra-high specific surface area and ultra-low density, including as an adsorption material, drug carrier, foam substitute, thermal insulation material and support skeleton.
[0003] At present, the precursor materials of organic aerogels are mostly polysaccharide polymers such as cellulose and sodium alginate, which are generally prepared by the sol-gel method. However, the process of preparing aerogels often requires a high concentration of alkaline solution as a solvent. The subsequent waste liquid treatment brings huge costs and does not conform to the concept of green chemistry.
[0004] As the second most abundant natural organic polymer in nature, starch has the advantages of large raw material yield, high biocompatibility, low cost, and green processing. However, natural starch is usually hydrophilic and extremely sensitive to water due to capillary forces. Increased humidity in the environment will cause the aerogel to shrink sharply and the internal pores to collapse, which will be limited in specific high-performance applications. For the above reasons, in order to broaden the application field of starch resources and increase the added value, it is urgent to develop a processing method for shape memory glucose-based aerogels. Summary of the invention
[0005] In order to solve the defects of the prior art, the present invention provides a shape memory glucose-based aerogel and its preparation method and application. The glucose-based aerogel has low density, high porosity, and shape memory function, that is, it has the structural adsorption characteristics of the original hydrogel, and the swelling water absorption rate exceeds 90%; it can be used as a carrier for delivering and controlling the release of active substances, food packaging, biomedical materials, etc., and the scope of application can involve the fields of food, medicine, etc.; and the reaction is green and controllable, the operation is efficient and simple, and the product is green and environmentally friendly, etc., realizing the green and efficient preparation of shape memory glucose-based aerogel materials.
[0006] The first object of the present invention is to provide a method for preparing a shape memory glucose-based aerogel, the method comprising the following steps:
[0007] (1) dissolving the dextran particles in a buffered salt solution to prepare a dextran substrate solution, and then adding a donor molecule to form a mixed solution system; the pH value of the buffered salt solution is 5.0 to 7.0;
[0008] (2) adding 30-200 U / g of substrate carbohydrase to the mixed solution system of step (1) to carry out a reaction, and after the reaction is completed, the mixture is allowed to stand to obtain a gel solution;
[0009] (3) Dehydrating the gel solution prepared in step (2) under supercritical conditions to obtain a shape memory glucose-based aerogel.
[0010] In one embodiment, the donor molecule in step (1) includes one or more of sucrose, linear dextrin, maltose, and phosphorylated glucose derivatives.
[0011] In one embodiment, the carbohydrase in step (2) is one or more multifunctional amylases from hydrolase families 13, 57, and 77 that can extend α-1,4 chains on the particle surface.
[0012] In one embodiment, the carbohydrase comprises one or more of GH13 multifunctional amylosucrase, GH57 multifunctional amylomaltase and GH77 multifunctional starch α-transglycosylase.
[0013] In one embodiment, the buffer solution in step (1) comprises any one of phosphate buffer solution, citrate buffer, carbonate buffer, acetate buffer, barbiturate buffer, and Tris buffer.
[0014] In one embodiment, the concentration of the glucan substrate solution in step (1) is 10-40%.
[0015] In one embodiment, the mass amount of the donor molecule added in step (1) is 5-30 times the mass of the dextran substrate.
[0016] In one embodiment, the reaction conditions of step (2) are: temperature of 20-50°C and time of 2-36h.
[0017] In one embodiment, the supercritical conditions in step (3) are: pressure of 7.5-12.0 MPa and temperature of 32-45°C.
[0018] In one embodiment, the particle size of the dextran particles in step (1) is 30-200 nm and the molecular weight is 10 7 -10 8 g / mol, amylose content>10%.
[0019] In one embodiment, the density of the shape memory glucose-based aerogel in step (3) is 0.05-0.25 g / cm 3 , porosity 85%-95%, swelling water content over 90%.
[0020] The second object of the present invention is to provide a shape memory glucose-based aerogel prepared by the above method.
[0021] The third object of the present invention is to provide an application of the shape memory glucose-based aerogel described above in the delivery and controlled release of active substance carriers, food packaging, and biomedical materials.
[0022] The present invention has the following advantages:
[0023] 1. The glucan particles extracted from the natural endosperm of cereal grains not only have good biocompatibility and biodegradability, are non-toxic and harmless, but also transform renewable and degradable biomass resources into high value-added aerogel materials, broadening the application fields and channels of glucan resources.
[0024] 2. Shape memory glucose-based aerogels are obtained by using bioenzymatic catalysis and in-situ dehydration technology. The enzymatic method is efficient and mild, the process is safe and controllable, the operation is simple and environmentally friendly, and the green and efficient preparation of glucose-based aerogel materials is achieved. The density is 0.05-0.25g / cm 3 , porosity 85%-95%, and the aerogel material has shape memory function, that is, it has the structural adsorption characteristics of the original hydrogel, and the swelling water absorption rate exceeds 90%.
[0025] 3. The shape memory glucose-based aerogel material of the present invention has the properties of being porous, ultra-low density, and having a high swelling water content, and can be used to construct delivery and controlled release carriers of active substances, food packaging, biomedical materials, and the like. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is a scanning electron microscope image of the shape memory glucose-based aerogel prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0027] The content of the present invention is further explained below with reference to examples, but the content protected by the present invention is not limited to the following examples.
[0028] Density determination: Use an electronic balance to weigh the mass M of the aerogel, then use a vernier caliper to measure the size of the dried aerogel and calculate the volume V. The density of the aerogel = M / V.
[0029] Porosity measurement: As an important parameter to characterize the structure of aerogel, it refers to the proportion of pores inside the material to the total volume of the material. The porosity is determined by using the volume density of the sample and the true density of starch (1.5 g / cm 3 ) to calculate the porosity.
[0030] Determination of swelling water content: First, weigh the aerogel accurately, then soak the aerogel in water and gently absorb the water overflowing from the surface of the gel with filter paper, and accurately weigh the hydrogel that effectively holds water. The swelling water content is expressed as the mass ratio of the water content in the hydrogel to the aerogel.
[0031] Source of glucan particles: extracted from natural plant endosperm such as corn, rice, wheat, sorghum, etc. Specific extraction process: The grain particles are crushed, partially acid-lyzed, extracted, graded, precipitated, and dried to obtain glucan particles with a particle size of 30-200nm and a molecular weight of 10 7 -10 8 g / mol, linear dextran content>10%.
[0032] The source of the hydrolase family GH13 multifunctional starch sucrase, GH57 multifunctional starch maltase, and GH 77 multifunctional starch α-glycosylase is: any one of thermophilic stearobacillus, thermophilic archaea, thermophilic Thermus, and extreme thermophilic archaea is screened from nature, and the enzyme is obtained through activation culture and fermentation. The transaminase activity: hydrolase activity>30 can be obtained from the reference literature (Microbial Starch-Converting Enzymes: Recent Insights and Perspectives. Ming Miao, Comprehensive Reviews in Food Science and Food Safety. 2018).
[0033] Transaminase activity refers to the activity of reducing the absorbance of the amylose-iodine complex at 660nm, and is based on the ability of the glycosidase to cut the α-1,4 glycosidic bond and transfer it to the 4-hydroxyl group on another glucose residue to form an α-1,4 bond to reduce the linear fragment. Unit enzyme activity definition: the amount of enzyme used to reduce the absorbance value at 660nm by 1% per minute; hydrolase activity refers to the ability of starch sugar chains to depolymerize to form small molecules such as glucose and dextrin. Unit enzyme activity is defined as the enzyme used to hydrolyze water-soluble starch for 1 hour to produce 1mg of glucose.
[0034] Example 1
[0035] A method for preparing shape memory glucose-based aerogel specifically comprises the following steps:
[0036] Weigh 100 g of corn-derived glucan particles (particle size 75 nm, molecular weight 3.7 × 10 7g / mol, linear glucan content 13%) was dissolved in a pH 7.0 phosphate buffer solution to prepare a 10% substrate solution, and sucrose 10 times the mass of the substrate was added and mixed evenly, and 80U / g of substrate GH13 multifunctional starch sucrase (transglycosidase activity: hydrolase activity = 51) was added, and the solution was reacted at 25°C for 10h, and then allowed to stand to obtain a gel; the obtained gel was dehydrated under supercritical conditions of 32°C and 10.0MPa to obtain the target product, shape memory glucose-based aerogel.
[0037] After analysis and measurement, it is known that the density of shape memory glucose-based aerogel is 0.12g / cm 3 , porosity 91%, swelling water content 94%.
[0038] Example 2
[0039] Weigh 100 g of potato-derived glucan particles (particle size 41 nm, molecular weight 1.8 × 10 7 g / mol, linear glucan content 28%) was dissolved in a pH 5.0 citrate buffer solution to prepare a 20% substrate solution, and linear dextrin 8 times the mass of the substrate was added and mixed evenly, and 50U / g of substrate GH57 multifunctional starch maltase (transglycosidase activity: hydrolase activity = 36) was added and then allowed to react at 35°C for 4h, and then allowed to stand to obtain a gel; the obtained gel was placed under supercritical conditions of 45°C and 7.5MPa for dehydration to obtain the target product, shape memory glucose-based aerogel.
[0040] After analysis and measurement, it is known that the density of shape memory glucose-based aerogel is 0.17g / cm 3 , porosity 89%, swelling water content 91%.
[0041] Example 3
[0042] Weigh 100 g of rice-derived glucan particles (particle size 52 nm, molecular weight 0.64 × 10 7 g / mol, linear glucan content 24%) was dissolved in a pH 6.5 phosphate buffer solution to prepare a 30% substrate solution, and 22 times the mass of maltose was added and mixed evenly, and 50U / g of substrate GH 77 multifunctional starch α-transglycosylase (transglycosidase activity: hydrolase activity = 40) was added and then allowed to react at 42°C for 7h, and then allowed to stand to obtain a gel; the obtained gel was placed under supercritical conditions of 37°C and 11.0MPa for dehydration to obtain the target product, shape memory glucosyl aerogel.
[0043] After analysis and measurement, it is known that the density of shape memory glucose-based aerogel is 0.09g / cm 3 , porosity 93%, swelling water content 92%.
[0044] Comparative Example 1
[0045] Referring to Example 1, the addition amount of the donor molecule sucrose was set to 1 times the mass of the substrate, and other conditions remained unchanged to prepare the target product, shape memory glucose-based aerogel. The performance measurement results of the obtained product are shown in Table 1.
[0046] Comparative Example 2
[0047] Referring to Example 1, the dosage of GH13 multifunctional starch sucrase was adjusted to 10 U / g substrate and 300 U / g substrate, respectively, and other conditions remained unchanged to prepare the target product shape memory glucose-based aerogel. The performance measurement results of the obtained product are shown in Table 1.
[0048] Comparative Example 3
[0049] Referring to Example 1, the corn-derived glucan particles were replaced with waxy corn starch, and other conditions remained unchanged to prepare the target product. The results of the obtained product are shown in Table 1.
[0050] Table 1 Performance results of the products obtained in Comparative Examples 1-3
[0051]
[0052]
[0053] Comparative Example 4
[0054] Referring to Example 1, the GH13 multifunctional amylosucrase was replaced with α-glucosidase, and other conditions remained unchanged.
[0055] The results showed that the corn-derived glucan particles were hydrolyzed, the solution became thinner, and could not form a gel, that is, shape memory glucan-based aerogel could not be formed.
[0056] The specific implementation cases described in this application are only used as examples to illustrate the spirit of the present invention and some experiments. Those skilled in the art of the present invention may make various modifications or supplements to the specific implementation cases described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.
Claims
1. A method for preparing shape memory glucose-based aerogel, characterized in that: The method comprises the following steps: (1) Dissolving dextran particles in a buffered salt solution to prepare a dextran substrate solution, and then adding donor molecules to form a mixed solution system; the pH value of the buffered salt solution is 5.0-7.0; the donor molecules include one or more of sucrose, maltose, linear dextrin, and phosphorylated glucose derivatives; the mass of the donor molecules added is 5-30 times the mass of the dextran substrate; the particle size of the dextran particles is 30-200 nm, and the molecular weight is 10 7 -10 8 g / mol, amylose content>10%; (2) adding 30-200 U / g of substrate carbohydrase to the mixed solution system of step (1) to carry out reaction, and after the reaction is completed, the carbohydrase is allowed to stand to obtain a gel solution; the carbohydrase comprises one or more of GH13 multifunctional starch sucrase, GH57 multifunctional starch maltase and GH77 multifunctional starch α-transglycosylase; (3) Dehydrating the gel solution prepared in step (2) under supercritical conditions to obtain shape memory glucose-based aerogel.
2. The method according to claim 1, characterized in that The concentration of the glucan substrate solution in step (1) is 10-40%.
3. The method according to claim 1, characterized in that The reaction conditions of step (2) are: temperature of 20-50°C and time of 2-36 h.
4. The method according to claim 1, characterized in that The supercritical conditions in step (3) are: pressure of 7.5-12.0 MPa and temperature of 32-45°C.
5. The method according to claim 1, characterized in that The buffer solution in step (1) includes any one of phosphate buffer solution, citrate buffer solution, carbonate buffer solution, acetate buffer solution, barbiturate buffer solution, and Tris buffer solution.
6. A shape memory glucose-based aerogel prepared by the method according to any one of claims 1 to 5.
7. Use of the shape memory glucose-based aerogel according to claim 6 in the delivery and controlled release of active substance carriers, food packaging, and biomedical materials.