A method for preparing amino acid-based degradable material

Abstract

The present invention relates to the technical field of degradable materials, and in particular to a method for preparing an amino acid-based degradable material, comprising the following steps: S1.1, converting calcium glutamate into an amidate under catalysis; S1.2, mixing the amidate with threonine phosphate to obtain a sediment; S1.3, further modifying the sediment with citric acid to obtain a degradable substrate; S1.4, thoroughly and uniformly mixing the degradable substrate, a bioactive molecule, a plasticizer, a stabilizer, and an antioxidant, and then extruding the mixture with a twin-screw extruder to obtain an amino acid-based degradable material; wherein the degradable substrate is prepared from calcium glutamate, threonine phosphate, and citric acid in a mass ratio of 7:3-4:0.5-1; calcium glutamate is used to construct a basic skeleton of the material, and threonine phosphate further enhances structural stability and improves mechanical strength, thereby balancing mechanical properties and degradation cycle, and having broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable materials, in particular to a method for preparing an amino acid-based degradable material. Background Art

[0002] Traditional plastics have been widely used around the world due to their lightness, durability and low cost. However, these plastics are difficult to degrade in the natural environment, and long-term accumulation has led to serious environmental pollution problems. Plastic waste not only destroys the natural landscape, but also poses a huge threat to the marine ecosystem. Many marine organisms die from accidentally ingesting plastic. With the enhancement of environmental awareness and the introduction of environmental protection regulations, degradable materials have gradually received attention. Degradable materials refer to materials that can be quickly decomposed into harmless substances in the natural environment or through the action of microorganisms. The use of these materials can reduce pollution to the environment and reduce the threat of plastic waste to the ecosystem.

[0003] Although biodegradable materials have many advantages, there are still some problems in their practical applications. For example, amino acid-based biodegradable materials have insufficient mechanical properties due to their weak intermolecular forces, low molecular weight, low crystallinity and rapid degradation rate, which limits their application range. In view of this, we propose a preparation method for amino acid-based biodegradable materials. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing an amino acid-based degradable material to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides a method for preparing an amino acid-based degradable material.

[0006] S1.1, converting calcium glutamate into an amidate under catalysis;

[0007] S1.2, mixing the amidate with phosphothreonine to prepare a sediment;

[0008] S1.3, further modifying the sediment with citric acid to obtain a degradable substrate;

[0009] S1.4. After thoroughly mixing the biodegradable substrate, bioactive molecule, plasticizer, stabilizer, and antioxidant, the mixture is extruded using a twin-screw extruder to obtain an amino acid-based biodegradable material.

[0010] The degradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3-4:0.5-1;

[0011] The stabilizer is one or more combinations of modified starch, cellulose nanocrystals and microcrystalline cellulose.

[0012] Preferably, in S1.1, the specific preparation steps of the amidate are:

[0013] Calcium glutamate is dissolved in deionized water to prepare a calcium glutamate solution with a concentration of 0.1-0.5M, a catalyst is added, and the solution is stirred at room temperature for 20-30 minutes until the catalytic reaction is complete. The solution is then transferred to a constant temperature water bath at 80-90°C under nitrogen protection and stirred at 200-300 rpm for 2-4 hours, cooled, washed, and dried to obtain an amidate.

[0014] Preferably, the catalyst is obtained by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5-1, and the catalyst accounts for 12-16% of the mass of calcium glutamate.

[0015] Preferably, in S1.2, the specific steps of preparing the sediment are:

[0016] The amidate is dispersed in deionized water, wherein the solid-liquid ratio of the amidate to the deionized water is 1:5-10, phosphothreonine is added to form a mixed solution, the pH of the mixed solution is adjusted to 8-9, and the mixture is stirred and reacted at 60-70° C. and 100-200 rpm for 2-3 hours to obtain a composite solution, and the pH of the composite solution is further adjusted to 10.5-11, and the mixture is transferred to a high-pressure reactor, heated to 120-150° C., reacted for 10-12 hours, and centrifuged, washed, and dried to obtain a sediment.

[0017] Preferably, in S1.3, the specific steps for preparing the degradable substrate are:

[0018] Citric acid is dissolved in deionized water to prepare a citric acid solution with a concentration of 0.1-0.3 mol / L. The sediment is immersed in the citric acid solution with a mass ratio of citric acid to sediment of 0.5-1:10. The solution is stirred at a speed of 100-150 rpm for 1-2 hours at 40-50° C., and finally centrifuged, washed, and dried to obtain a degradable substrate.

[0019] Calcium glutamate contains carboxyl groups, amino groups and calcium ions. The dehydration condensation reaction between the carboxyl groups and amino groups of calcium glutamate forms an amide bond to make an amino acid-based degradable material. At the same time, phosphothreonine is added. Since the amino and carboxyl groups on the phosphothreonine can participate in the cross-linking reaction, they form an amide bond with calcium glutamate and form a hydrogen bond network, thereby enhancing the cohesion of the material and improving the stability of the material. In addition, the phosphate group on the phosphothreonine can combine with the calcium ions on the calcium glutamate through electrostatic interaction and chemical bonds to form calcium phosphate, and by promoting the transformation of calcium phosphate into hydroxyapatite, the hydroxyapatite is finally deposited on the surface of the amino acid-based degradable material and evenly distributed. Since hydroxyapatite has strong mechanical properties, the mechanical strength of the amino acid-based degradable material is effectively improved. However, hydroxyapatite is difficult to decompose, so citric acid is introduced to provide hydrophilicity, thereby accelerating its decomposition rate. This is beneficial for improving the mechanical strength while controlling its degradation rate so that it does not extend excessively, thereby expanding the scope of application.

[0020] Preferably, in S1.4, the bioactive molecule is one or more combinations of hyaluronic acid, curcumin and tea tree oil; the curcumin is purchased from Hubei Sanxin Pharmaceutical Technology Co., Ltd.; and the tea tree oil is purchased from Shanghai Koraman Reagent Co., Ltd.

[0021] Preferably, in S1.4, the plasticizer is one or more combinations of glycerol, polyethylene glycol and triethyl citrate.

[0022] Preferably, in S1.4, the antioxidant is one or more combinations of vitamin E, rosemary extract and green coffee bean extract.

[0023] Preferably, the modified starch is obtained by oxidizing starch with hydrogen peroxide.

[0024] Preferably, in S1.4, the degradable substrate comprises 74-83 parts by weight, the bioactive molecule comprises 2-7 parts by weight, the plasticizer comprises 5-13 parts by weight, the stabilizer comprises 1-4 parts by weight, and the antioxidant comprises 0.2-0.8 parts by weight.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In the preparation method of the amino acid-based degradable material, the synergistic effect of calcium glutamate, phosphothreonine and citric acid is utilized to significantly improve the mechanical properties and controllable degradability of the material. Calcium glutamate forms amide bonds through dehydration condensation of carboxyl groups and amino groups to build the basic skeleton of the material. At the same time, phosphothreonine participates in the cross-linking reaction to form amide bonds and hydrogen bond networks with calcium glutamate, thereby enhancing cohesion. In addition, the phosphate group of phosphothreonine and the calcium ion of calcium glutamate can combine to form hydroxyapatite, which is uniformly deposited on the surface of the material, greatly improving the mechanical strength. The introduction of citric acid imparts hydrophilicity to the material, accelerates the degradation rate, and balances the mechanical properties and degradation cycle. This overcomes the problems of traditional degradable materials with good mechanical properties but long degradation cycles and single functions, and has broad application prospects. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] A method for preparing an amino acid-based degradable material of the present invention:

[0029] S1.1, converting calcium glutamate into an amidate under catalysis;

[0030] S1.2, mixing the amidate with phosphothreonine to prepare a sediment;

[0031] S1.3, further modifying the sediment with citric acid to obtain a degradable substrate;

[0032] S1.4. After thoroughly mixing the biodegradable substrate, bioactive molecule, plasticizer, stabilizer, and antioxidant, the mixture is extruded using a twin-screw extruder to obtain an amino acid-based biodegradable material.

[0033] The degradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3-4:0.5-1;

[0034] The bioactive molecule is one or more combinations of hyaluronic acid, curcumin and tea tree oil, and the bioactive molecule is preferably tea tree oil;

[0035] The plasticizer is one or more combinations of glycerol, polyethylene glycol and triethyl citrate, and the plasticizer is preferably triethyl citrate;

[0036] The antioxidant is one or more combinations of vitamin E, rosemary extract and green coffee bean extract, and the antioxidant is preferably rosemary extract;

[0037] The stabilizer is one or more combinations of modified starch, cellulose nanocrystals, and microcrystalline cellulose, wherein the modified starch is obtained by oxidizing starch with hydrogen peroxide, and the stabilizer is preferably a mixture of modified starch and microcrystalline cellulose in a mass ratio of 3:1;

[0038] The main active ingredients in rosemary extract include terpenoids (monoterpenes, sesquiterpenes, and diterpenes), phenolic acids (rosmarinic acid and its derivatives), flavonoids (luteolin and its glycosides, apigenins), and volatile oils (α-pinene, β-pinene).

[0039] The main active ingredients in green coffee bean extract include chlorogenic acid compounds (chlorogenic acid and its isomers), trigonelline, fats (triglycerides, etc.) and nitrogen-containing compounds (amino acids, alkaloids).

[0040] Example 1: A method for preparing an amino acid-based degradable material, comprising the following steps:

[0041] S1.1. Dissolve calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, add the catalyst, and stir at room temperature for 30 min. Then, under nitrogen, transfer to a 90°C constant temperature water bath and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate.

[0042] The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate.

[0043] S1.2. Dispersing the amidate in deionized water at a solid-to-liquid ratio of 1:5, adding phosphothreonine to form a mixed solution, adjusting the pH of the mixed solution to 9, stirring and reacting at 70°C and 200 rpm for 3 hours to obtain a composite solution, further adjusting the pH of the composite solution to 11, transferring the solution to an autoclave, heating it to 150°C, reacting it for 12 hours, and centrifuging, washing, and drying to obtain a sediment;

[0044] S1.3. Dissolve citric acid in deionized water to prepare a 0.3 mol / L citric acid solution. Immerse the sediment in the citric acid solution at a mass ratio of citric acid to sediment of 0.5:10. Stir at 150 rpm for 2 h at 40°C, then centrifuge, wash, and dry to obtain a degradable substrate.

[0045] The biodegradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3:0.5;

[0046] S1.4. After thoroughly mixing 83 parts by weight of a degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of a stabilizer and 0.8 parts by weight of a rosemary extract, the mixture was extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0047] Example 2: A method for preparing an amino acid-based degradable material, comprising the following steps:

[0048] S1.1. Dissolve calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, add the catalyst, and stir at room temperature for 30 min. Then, under nitrogen, transfer to a 90°C constant temperature water bath and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate.

[0049] The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate.

[0050] S1.2. Dispersing the amidate in deionized water at a solid-to-liquid ratio of 1:5, adding phosphothreonine to form a mixed solution, adjusting the pH of the mixed solution to 9, stirring and reacting at 70°C and 200 rpm for 3 hours to obtain a composite solution, further adjusting the pH of the composite solution to 11, transferring the solution to an autoclave, heating it to 150°C, reacting it for 12 hours, and centrifuging, washing, and drying to obtain a sediment;

[0051] S1.3. Dissolve citric acid in deionized water to prepare a 0.3 mol / L citric acid solution. Immerse the sediment in the citric acid solution at a mass ratio of citric acid to sediment of 0.5:10. Stir at 150 rpm for 2 h at 40°C, then centrifuge, wash, and dry to obtain a degradable substrate.

[0052] The biodegradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3.5:0.7;

[0053] S1.4. After thoroughly mixing 83 parts by weight of a degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of a stabilizer and 0.8 parts by weight of a rosemary extract, the mixture was extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0054] Example 3: A method for preparing an amino acid-based degradable material, comprising the following steps:

[0055] S1.1. Dissolve calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, add the catalyst, and stir at room temperature for 30 min. Then, under nitrogen, transfer to a 90°C constant temperature water bath and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate.

[0056] The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate.

[0057] S1.2. Dispersing the amidate in deionized water at a solid-to-liquid ratio of 1:5, adding phosphothreonine to form a mixed solution, adjusting the pH of the mixed solution to 9, stirring and reacting at 70°C and 200 rpm for 3 hours to obtain a composite solution, further adjusting the pH of the composite solution to 11, transferring the solution to an autoclave, heating it to 150°C, reacting it for 12 hours, and centrifuging, washing, and drying to obtain a sediment;

[0058] S1.3. Dissolve citric acid in deionized water to prepare a 0.3 mol / L citric acid solution. Immerse the sediment in the citric acid solution at a mass ratio of citric acid to sediment of 0.5:10. Stir at 150 rpm for 2 h at 40°C, then centrifuge, wash, and dry to obtain a degradable substrate.

[0059] The biodegradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3.5:1;

[0060] S1.4. After thoroughly mixing 83 parts by weight of a degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of a stabilizer and 0.8 parts by weight of a rosemary extract, the mixture was extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0061] Example 4: A method for preparing an amino acid-based degradable material, comprising the following steps:

[0062] S1.1. Dissolve calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, add the catalyst, and stir at room temperature for 30 min. Then, under nitrogen, transfer to a 90°C constant temperature water bath and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate.

[0063] The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate.

[0064] S1.2. Dispersing the amidate in deionized water at a solid-to-liquid ratio of 1:5, adding phosphothreonine to form a mixed solution, adjusting the pH of the mixed solution to 9, stirring and reacting at 70°C and 200 rpm for 3 hours to obtain a composite solution, further adjusting the pH of the composite solution to 11, transferring the solution to an autoclave, heating it to 150°C, reacting it for 12 hours, and centrifuging, washing, and drying to obtain a sediment;

[0065] S1.3. Dissolve citric acid in deionized water to prepare a 0.3 mol / L citric acid solution. Immerse the sediment in the citric acid solution at a mass ratio of citric acid to sediment of 0.5:10. Stir at 150 rpm for 2 h at 40°C, then centrifuge, wash, and dry to obtain a degradable substrate.

[0066] The biodegradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3.5:0.7;

[0067] S1.4. After thoroughly mixing 83 parts by weight of a degradable substrate, 2 parts by weight of tea tree oil, 5 parts by weight of triethyl citrate, 1 part by weight of a stabilizer and 0.2 parts by weight of a rosemary extract, the mixture was extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0068] Example 5: A method for preparing an amino acid-based degradable material, comprising the following steps:

[0069] S1.1. Dissolve calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, add the catalyst, and stir at room temperature for 30 min. Then, under nitrogen, transfer to a 90°C constant temperature water bath and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate.

[0070] The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate.

[0071] S1.2. Dispersing the amidate in deionized water at a solid-to-liquid ratio of 1:5, adding phosphothreonine to form a mixed solution, adjusting the pH of the mixed solution to 9, stirring and reacting at 70°C and 200 rpm for 3 hours to obtain a composite solution, further adjusting the pH of the composite solution to 11, transferring the solution to an autoclave, heating it to 150°C, reacting it for 12 hours, and centrifuging, washing, and drying to obtain a sediment;

[0072] S1.3. Dissolve citric acid in deionized water to prepare a 0.3 mol / L citric acid solution. Immerse the sediment in the citric acid solution at a mass ratio of citric acid to sediment of 0.5:10. Stir at 150 rpm for 2 h at 40°C, then centrifuge, wash, and dry to obtain a degradable substrate.

[0073] The biodegradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3.5:0.7;

[0074] S1.4. After thoroughly mixing 74 parts by weight of a degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of a stabilizer and 0.8 parts by weight of a rosemary extract, the mixture was extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0075] Example 6: A method for preparing an amino acid-based degradable material, comprising the following steps:

[0076] S1.1. Dissolve calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, add the catalyst, and stir at room temperature for 30 min. Then, under nitrogen, transfer to a 90°C constant temperature water bath and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate.

[0077] The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate.

[0078] S1.2. Dispersing the amidate in deionized water at a solid-to-liquid ratio of 1:5, adding phosphothreonine to form a mixed solution, adjusting the pH of the mixed solution to 9, stirring and reacting at 70°C and 200 rpm for 3 hours to obtain a composite solution, further adjusting the pH of the composite solution to 11, transferring the solution to an autoclave, heating it to 150°C, reacting it for 12 hours, and centrifuging, washing, and drying to obtain a sediment;

[0079] S1.3. Dissolve citric acid in deionized water to prepare a 0.3 mol / L citric acid solution. Immerse the sediment in the citric acid solution at a mass ratio of citric acid to sediment of 0.5:10. Stir at 150 rpm for 2 h at 40°C, then centrifuge, wash, and dry to obtain a degradable substrate.

[0080] The biodegradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3.5:0.7;

[0081] S1.4. After thoroughly mixing 79 parts by weight of a degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of a stabilizer and 0.8 parts by weight of a rosemary extract, the mixture was extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0082] Comparative Example 1: The method of Example 2 was adopted, and calcium glutamate was directly used without modifying the calcium glutamate with phosphothreonine and citric acid.

[0083] Comparative Example 2: The method of Example 2 was adopted, and calcium glutamate and phosphothreonine were used directly without modifying calcium glutamate and phosphothreonine with citric acid.

[0084] Comparative Example 3: The method of Example 2 was adopted, and calcium glutamate and citric acid were directly used without modifying calcium glutamate and citric acid by phosphothreonine.

[0085] The present invention is an amino acid-based degradable material prepared by using a degradable substrate, wherein the performance index inspection items and inspection standards of the amino acid-based degradable material are as follows:

[0086] The mechanical strength of the material was quantified by tensile testing machine, with a load of 30 MPa, a speed of 5 mm / min, and a standard dumbbell-shaped specimen (length 75 mm, gauge length 25 × 4 × 2 mm 3 ), test its initial tensile strength, and soak it in an acidic environment at 37℃ and pH=5.5 for 7 days to test its tensile strength and mass loss rate (degradation rate), and use 1.5wt% enzymatic hydrolyzate (lipase: protease=2:1) ​​to degrade at a constant temperature of 37℃ for 7 days to test its tensile strength and degradation rate, and then use humus: vermiculite=3:1 (w / w), moisture content of 30%, temperature of 25℃, combined with soil microbial degradation for 30 days to test its tensile strength and degradation rate.

[0087] The amino acid-based degradable materials prepared in Examples 1-6 and Comparative Examples 1-3 were tested using the above standards, and the obtained data are shown in Table 1:

[0088] Table 1 Performance data of Examples 1-6 and Comparative Examples 1-3

[0089]

[0090] The above data fully demonstrate that Examples 1-6, compared with Comparative Examples 1-3, can fully demonstrate the effect of the degradable substrate on the mechanical properties and degradation rate of the amino acid-based degradable material.

[0091] Since the present invention uses a degradable substrate to prepare the amino acid-based degradable material, the degradable substrate effectively improves the mechanical properties and degradation rate of the amino acid-based degradable material, as follows:

[0092] It can be seen from Examples 1-3 that with the continuous increase in the content of calcium glutamate, threonine phosphate and citric acid, the mechanical properties of the amino acid-based degradable material first increase and then decrease. Since threonine phosphate has a cross-linking effect, it can increase the cohesion of the amino acid-based degradable material, improve the stability of the material, and deposit hydroxyapatite to improve the mechanical properties. Therefore, the mechanical properties of the amino acid-based degradable material gradually increase. However, with the increase of citric acid content, the hydrophilicity of the amino acid-based degradable material is enhanced, so the degradation rate of the material increases, so the mechanical properties of the amino acid-based degradable material decrease. As the mechanical properties increase, since hydroxyapatite is not easy to decompose, the degradation rate of the amino acid-based degradable material is slower.

[0093] It can be seen from Examples 3 and 4 that with the continuous increase in the content of other components, the mechanical properties and degradation rate of the amino acid-based degradable material do not change significantly, indicating that small changes in other components to a certain extent are not sufficient to significantly affect the mechanical properties and degradation rate of the amino acid-based degradable material.

[0094] It can be seen from Examples 2, 5 and 6 that as the content of the degradable substrate continues to change, the mechanical properties and degradation rate of the amino acid-based degradable material continue to change. The increase in the content of the degradable substrate means that the content of the skeleton part in the amino acid-based degradable material also gradually increases, and therefore the mechanical properties gradually increase.

[0095] According to the above test experiments, the amino acid-based degradable material prepared according to Example 2 has the best performance, so Example 2 is taken as the best example;

[0096] By comparing Example 2 with Comparative Examples 1-3, it can be seen that:

[0097] In Comparative Example 1, calcium glutamate was directly used without modification by phosphothreonine and citric acid. The mechanical properties and degradation rate of the amino acid-based degradable material were poor. Phosphothreonine formed a cross-linked structure with calcium glutamate and promoted the formation of hydroxyapatite, effectively enhancing the cohesion and mechanical strength of the material; citric acid increased the hydrophilicity of the material and helped to regulate the degradation rate. Therefore, the unmodified material exhibited poor mechanical properties and undesirable degradation behavior due to the lack of these strengthening mechanisms, indicating the importance of multi-component synergy in the preparation of amino acid-based degradable materials.

[0098] Comparative Example 2 directly uses calcium glutamate and threonine phosphate, and does not modify calcium glutamate and threonine phosphate by citric acid. The mechanical properties and degradation rate of the amino acid-based degradable material are poor. Since threonine phosphate contains amino and carboxyl groups, it can form amide bonds with calcium glutamate, thereby enhancing the cross-linking network inside the material, and the phosphate group can form a stable chemical bond with the calcium ions in calcium glutamate, further promoting the deposition of hydroxyapatite, thereby effectively improving the mechanical strength of the material. However, the lack of citric acid, a hydrophilic component, cannot accelerate the degradation process of the material. This demonstrates the important role of threonine phosphate in improving the mechanical properties of the material and the indispensability of citric acid in regulating the degradation rate.

[0099] In Comparative Example 3, calcium glutamate and citric acid were directly used without modifying calcium glutamate and citric acid by phosphothreonine. The mechanical properties and degradation rate of the amino acid-based degradable material were poor. The cross-linking effect of phosphothreonine and the deposition of hydroxyapatite are important strengthening mechanisms for improving the mechanical strength of the material. Without the participation of phosphothreonine, the material contains a citric acid component, which further accelerates the degradation of the material and causes the performance of the material to decay rapidly.

[0100] In summary, the combined effects of calcium glutamate, threonine phosphate and citric acid can significantly improve the comprehensive performance of amino acid-based biodegradable materials. Calcium glutamate provides basic structural support for the material; threonine phosphate further enhances the stability of this structure and promotes the deposition of hydroxyapatite, thereby increasing the mechanical strength of the material. On this basis, citric acid plays a key role in regulating hydrophilicity and degradation rate. By providing additional hydrophilic sites, citric acid accelerates the degradation process of the material while ensuring the safety and biocompatibility of the degradation products. The combination of the three not only effectively improves the mechanical strength of the material, but also optimizes its degradation behavior and expands its application range.

[0101] The basic principles, main features, and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention claimed.

Claims

1. A method for preparing an amino acid-based degradable material, characterized in that: S1.1, converting calcium glutamate into an amidate under catalysis; S1.2, mixing the amidate with phosphothreonine to prepare a sediment; S1.3, further modifying the sediment with citric acid to obtain a degradable substrate; S1.

4. After thoroughly mixing the biodegradable substrate, bioactive molecule, plasticizer, stabilizer, and antioxidant, the mixture is extruded using a twin-screw extruder to obtain an amino acid-based biodegradable material. The degradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3-4:0.5-1; The stabilizer is one or more combinations of modified starch, cellulose nanocrystals and microcrystalline cellulose; In S1.4, the bioactive molecule is one or more combinations of hyaluronic acid, curcumin and tea tree oil.

2. The method for preparing an amino acid-based degradable material according to claim 1, wherein: In S1.1, the specific preparation steps of the amidate are: Calcium glutamate is dissolved in deionized water to prepare a calcium glutamate solution with a concentration of 0.1-0.5M, a catalyst is added, and the solution is stirred at room temperature for 20-30 minutes. Then, under nitrogen protection, the solution is transferred to a constant temperature water bath at 80-90°C and stirred at 200-300 rpm for 2-4 hours. The solution is cooled, washed, and dried to obtain an amidate.

3. The method for preparing an amino acid-based degradable material according to claim 2, wherein: The catalyst is prepared by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:0.5-1, and the catalyst accounts for 12-16% of the mass of calcium glutamate.

4. The method for preparing an amino acid-based degradable material according to claim 1, wherein: In S1.2, the specific steps for preparing the sediment are: The amidate is dispersed in deionized water, wherein the solid-liquid ratio of the amidate to the deionized water is 1:5-10, phosphothreonine is added to form a mixed solution, the pH of the mixed solution is adjusted to 8-9, and the mixture is stirred and reacted at 60-70° C. and 100-200 rpm for 2-3 hours to obtain a composite solution, and the pH of the composite solution is further adjusted to 10.5-11, and the mixture is transferred to a high-pressure reactor, heated to 120-150° C., reacted for 10-12 hours, and centrifuged, washed, and dried to obtain a sediment.

5. The method for preparing an amino acid-based degradable material according to claim 1, wherein: In S1.3, the specific steps for preparing the degradable substrate are: Citric acid is dissolved in deionized water to prepare a citric acid solution with a concentration of 0.1-0.3 mol / L. The sediment is immersed in the citric acid solution with a mass ratio of citric acid to sediment of 0.5-1:

10. The solution is stirred at a speed of 100-150 rpm for 1-2 hours at 40-50° C., and finally centrifuged, washed, and dried to obtain a degradable substrate.

6. The method for preparing an amino acid-based degradable material according to claim 1, wherein: In S1.4, the plasticizer is one or more combinations of glycerol, polyethylene glycol and triethyl citrate.

7. The method for preparing an amino acid-based degradable material according to claim 1, wherein: In S1.4, the antioxidant is one or more combinations of vitamin E, rosemary extract and green coffee bean extract.

8. The method for preparing an amino acid-based degradable material according to claim 1, wherein: The modified starch is obtained by oxidizing starch with hydrogen peroxide.

9. The method for preparing an amino acid-based degradable material according to claim 1, wherein: In the above S1.4, the degradable substrate comprises 74-83 parts by weight, the bioactive molecule comprises 2-7 parts by weight, the plasticizer comprises 5-13 parts by weight, the stabilizer comprises 1-4 parts by weight, and the antioxidant comprises 0.2-0.8 parts by weight.

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