Preparation method of amino acid-based degradable material

Abstract

The invention relates to the technical field of degradable materials, in particular to a preparation method of an amino acid-based degradable material, which comprises the following steps: S1.1, converting calcium glutamate into an amidate under the catalytic action; s1.2, mixing the amidate with threonine phosphate to prepare a sediment; s1.3, the sediment is further modified with citric acid, and a degradable base material is obtained; and S1.4, fully and uniformly mixing the degradable base material, the bioactive molecules, the plasticizer, the stabilizer and the antioxidant, and performing extrusion molding by using a double-screw extruder to obtain the amino acid-based degradable material. Wherein the degradable base material is prepared from calcium glutamate, threonine phosphate and citric acid according to the mass ratio of 7: (3-4): (0.5-1); the calcium glutamate is adopted to construct a material basic framework, the phosphothreonine further enhances the structural stability and improves the mechanical strength, the mechanical performance and the degradation period are balanced, and wide application prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable materials, and specifically, to a preparation method of an amino acid-based degradable material. Background Art

[0002] Due to their characteristics such as being lightweight, durable, and low in cost, traditional plastics have been widely used globally. 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 ingesting plastics. With the enhancement of environmental awareness and the introduction of environmental protection regulations, degradable materials have gradually attracted attention. Degradable materials refer to materials that can be decomposed into harmless substances relatively quickly in the natural environment or through the action of microorganisms. The use of these materials can reduce environmental pollution and the threat of plastic waste to the ecosystem.

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

[0004] The purpose of the present invention is to provide a preparation method of an amino acid-based degradable material to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides a preparation method of an amino acid-based degradable material. S1.1. Convert calcium glutamate into an amide compound under catalysis. S1.2. Mix the amide compound with threonine phosphate to prepare a sediment. S1.3. Further modify the sediment with citric acid to obtain a degradable substrate. S1.4. After fully mixing the degradable substrate, bioactive molecules, plasticizer, stabilizer, and antioxidant evenly, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material. Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate, and citric acid according to a mass ratio of 7:3 - 4:0.5 - 1. The stabilizer is one or a combination of modified starch, cellulose nanocrystals, and microcrystalline cellulose.

[0006] Preferably, in the above S1.1, the specific preparation steps of the amide compound are as follows: Dissolve calcium glutamate in deionized water to prepare a calcium glutamate solution with a concentration of 0.1 - 0.5 M. Add a catalyst and stir at room temperature for 20 - 30 min to complete the catalytic reaction. Then, under nitrogen protection, transfer it to a constant temperature water bath at 80 - 90 °C and stir at a speed of 200 - 300 rpm for 2 - 4 h. Cool, wash, and dry to obtain an amide compound.

[0007] 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.

[0008] Preferably, in S1.2, the specific preparation steps of the sediment are as follows: Disperse the amide compound in deionized water, where the solid-liquid ratio of the amide compound to deionized water is 1:5 - 10. Add threonine phosphate to form a mixed solution, adjust the pH of the mixed solution to 8 - 9, and stir and react at 60 - 70 °C and 100 - 200 rpm for 2 - 3 h to obtain a composite solution. Then adjust the pH of the composite solution to 10.5 - 11, transfer it to a high-pressure reactor, heat up to 120 - 150 °C, react for 10 - 12 h, centrifuge, wash, and dry to obtain the sediment.

[0009] Preferably, in S1.3, the specific preparation steps of the degradable substrate are as follows: Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.1 - 0.3 mol / L. Immerse the sediment in the citric acid solution, and the mass ratio of citric acid to the sediment is 0.5 - 1:10. Under the condition of 40 - 50 °C, stir at a speed of 100 - 150 rpm for 1 - 2 h, and finally centrifuge, wash, and dry to obtain the degradable substrate.

[0010] Calcium glutamate contains carboxyl, amino, and calcium ions. The dehydration condensation reaction between the carboxyl and amino groups of calcium glutamate is used to form an amide bond to prepare an amino-based degradable material. At the same time, adding threonine phosphate, since the amino and carboxyl groups on threonine phosphate can participate in cross-linking reactions, form amide bonds with calcium glutamate, and form a hydrogen bond network, enhancing the cohesion of the material and improving the stability of the material. In addition, the phosphate group on threonine phosphate can bind to the calcium ions on calcium glutamate through electrostatic interactions and chemical bonds to form calcium phosphate, and by promoting the transformation of calcium phosphate into hydroxyapatite, finally hydroxyapatite is deposited on the surface of the amino-based degradable material and is evenly distributed. Since hydroxyapatite has strong mechanical properties, the mechanical strength of the amino-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, which is beneficial to controlling the degradation rate without being overly extended while improving the mechanical strength, expanding the application range.

[0011] Preferably, in the step S1.4, the bioactive molecule is one or a combination of more than one of hyaluronic acid, curcumin and tea tree oil; the curcumin is purchased from Hubei Sanxin Medical Technology Co., Ltd.; the tea tree oil is purchased from Shanghai Kelaman Reagent Co., Ltd.

[0012] Preferably, in the step S1.4, the plasticizer is one or a combination of more than one of glycerol, polyethylene glycol and triethyl citrate.

[0013] Preferably, in the step S1.4, the antioxidant is one or a combination of more than one of vitamin E, rosemary extract and green coffee bean extract.

[0014] Preferably, the modified starch is obtained by oxidizing starch with hydrogen peroxide.

[0015] Preferably, in the step S1.4, the biodegradable substrate is 74 - 83 parts by weight, the bioactive molecule is 2 - 7 parts by weight, the plasticizer is 5 - 13 parts by weight, the stabilizer is 1 - 4 parts by weight, and the antioxidant is 0.2 - 0.8 parts by weight.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In the preparation method of the amino acid - based biodegradable material, by using the synergistic effect of calcium glutamate, threonine phosphate and citric acid, the mechanical properties and controllable degradability of the material are significantly improved. Calcium glutamate forms amide bonds through dehydration condensation of carboxyl groups and amino groups to construct the basic framework of the material. At the same time, threonine phosphate participates in the cross - linking reaction, forming amide bonds and hydrogen - bond networks with calcium glutamate to enhance the cohesion force. In addition, the phosphate group of threonine phosphate and the calcium ion of calcium glutamate can combine to generate hydroxyapatite, and deposit it evenly on the surface of the material, greatly improving the mechanical strength. And introducing citric acid endows the material with hydrophilicity, accelerating the degradation rate, balancing the mechanical properties and the degradation period, breaking through the problems of traditional biodegradable materials with good mechanical properties but long degradation periods and single functions, and having broad application prospects. Specific Embodiments

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0018] The preparation method of the amino acid - based biodegradable material of the present invention: S1.1. Convert 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 the degradable substrate, bioactive molecules, plasticizer, stabilizer and antioxidant are fully mixed, extrusion molding is performed using a twin-screw extruder to obtain an amino acid-based degradable material; The degradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3-4:0.5-1; Wherein, 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; The plasticizer is one or more combinations of glycerol, polyethylene glycol and triethyl citrate, and the plasticizer is preferably triethyl citrate; The antioxidant is one or more combinations of vitamin E, rosemary extract and green coffee bean extract, and the antioxidant is preferably rosemary extract; 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 prepared by mixing the modified starch and microcrystalline cellulose in a mass ratio of 3:1; The main active ingredients in rosemary extract include terpenoids (monoterpenes, sesquiterpenes, diterpenes), phenolic acid compounds (rosmarinic acid and its derivatives), flavonoids (luteolin and its glycosides, apigenins) and volatile oils (α-pinene, β-pinene); 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).

[0019] Embodiment 1: A method for preparing an amino acid-based degradable material, comprising the following steps: S1.1, dissolving calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, adding a catalyst, stirring at room temperature for 30 min, then transferring to a 90°C constant temperature water bath under nitrogen protection and stirring at 200 rpm for 4 h, cooling, washing and drying to obtain an amidate; The catalyst is obtained 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; S1.2. Disperse the amidate in deionized water, where the solid-liquid ratio of the amidate to deionized water is 1:5. Add threonine phosphate to form a mixed solution, adjust the pH of the mixed solution to 9, stir and react at 70 °C and 200 rpm for 3 h to obtain a composite solution. Then adjust the pH of the composite solution to 11, transfer it to a high-pressure reactor, heat up to 150 °C, react for 12 h, and centrifuge, wash, and dry to obtain a deposit; S1.3. Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.3 mol / L. Immerse the deposit in the citric acid solution, where the mass ratio of citric acid to the deposit is 0.5:10, and stir at 40 °C and 150 rpm for 2 h. Finally, centrifuge, wash, and dry to obtain a degradable substrate; Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate, and citric acid according to a mass ratio of 7:3:0.5; S1.4. After fully mixing 83 parts by weight of the 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 rosemary extract, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material.

[0020] Example 2: A method for preparing an amino acid-based degradable material, comprising the following steps: S1.1. Dissolve calcium glutamate in deionized water to prepare a calcium glutamate solution with a concentration of 0.1 M. Add a catalyst and stir at room temperature for 30 min. Then, under nitrogen protection, transfer it to a constant temperature water bath at 90 °C and stir at 200 rpm for 4 h. Cool, wash, and dry to obtain an amidate; Among them, the catalyst is obtained by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide according to a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate; S1.2. Disperse the amidate in deionized water, where the solid-liquid ratio of the amidate to deionized water is 1:5. Add threonine phosphate to form a mixed solution, adjust the pH of the mixed solution to 9, stir and react at 70 °C and 200 rpm for 3 h to obtain a composite solution. Then adjust the pH of the composite solution to 11, transfer it to a high-pressure reactor, heat up to 150 °C, react for 12 h, and centrifuge, wash, and dry to obtain a deposit; S1.3. Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.3 mol / L. Immerse the deposit in the citric acid solution, where the mass ratio of citric acid to the deposit is 0.5:10, and stir at 40 °C and 150 rpm for 2 h. Finally, centrifuge, wash, and dry to obtain a degradable substrate; Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate and citric acid according to a mass ratio of 7:3.5:0.7; S1.4. After fully mixing 83 parts by weight of the degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of stabilizer and 0.8 part by weight of rosemary extract, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material.

[0021] Example 3: A preparation method of an amino acid-based degradable material, comprising the following steps: S1.1. Dissolve calcium glutamate in deionized water to prepare a calcium glutamate solution with a concentration of 0.1 M, add a catalyst, stir at room temperature for 30 min, then under nitrogen protection, transfer to a constant temperature water bath at 90 °C and stir at a speed of 200 rpm for 4 h, cool, wash and dry to obtain an amidate; Among them, the catalyst is obtained by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide according to a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate; S1.2. Disperse the amidate in deionized water, wherein the solid-liquid ratio of the amidate to deionized water is 1:5, add threonine phosphate to form a mixed solution, adjust the pH of the mixed solution to 9, stir and react at 70 °C and 200 rpm for 3 h to obtain a composite solution, then adjust the pH of the composite solution to 11, transfer to a high-pressure reactor, heat up to 150 °C, react for 12 h, centrifuge, wash and dry to obtain a sediment; S1.3. Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.3 mol / L, soak the sediment in the citric acid solution, and the mass ratio of citric acid to the sediment is 0.5:10, and under the condition of 40 °C, stir at a speed of 150 rpm for 2 h, and finally centrifuge, wash and dry to obtain a degradable substrate; Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate and citric acid according to a mass ratio of 7:3.5:1; S1.4. After fully mixing 83 parts by weight of the degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of stabilizer and 0.8 part by weight of rosemary extract, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material.

[0022] Example 4: A preparation method of an amino acid-based degradable material, comprising the following steps: S1.1. Dissolve calcium glutamate in deionized water to prepare a calcium glutamate solution with a concentration of 0.1 M, add a catalyst, stir at room temperature for 30 min, then under nitrogen protection, transfer to a constant temperature water bath at 90 °C and stir at a speed of 200 rpm for 4 h, cool, wash and dry to obtain an amidate; The catalyst is obtained 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; S1.2, dispersing the amidate in deionized water, wherein the solid-liquid ratio of the amidate to the deionized water is 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, then adjusting the pH of the composite solution to 11, transferring the composite solution to a high-pressure reactor, heating to 150°C, reacting for 12 hours, centrifuging, washing and drying to obtain a sediment; S1.3, dissolving citric acid in deionized water to prepare a 0.3 mol / L citric acid solution, immersing the sediment in the citric acid solution, with the mass ratio of citric acid to sediment being 0.5:10, stirring at 150 rpm for 2 h at 40°C, and finally centrifugally washing and drying to obtain a degradable substrate; The degradable substrate is prepared from calcium glutamate, phosphothreonine and citric acid in a mass ratio of 7:3.5:0.7; S1.4. After thoroughly mixing 83 parts by weight of the 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 rosemary extract, the mixture is extruded using a twin-screw extruder to obtain an amino acid-based degradable material.

[0023] Example 5: A method for preparing an amino acid-based degradable material, comprising the following steps: S1.1, dissolving calcium glutamate in deionized water to prepare a 0.1 M calcium glutamate solution, adding a catalyst, stirring at room temperature for 30 min, then transferring to a 90°C constant temperature water bath under nitrogen protection and stirring at 200 rpm for 4 h, cooling, washing and drying to obtain an amidate; The catalyst is obtained 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; S1.2, dispersing the amidate in deionized water, wherein the solid-liquid ratio of the amidate to the deionized water is 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, then adjusting the pH of the composite solution to 11, transferring the composite solution to a high-pressure reactor, heating to 150°C, reacting for 12 hours, centrifuging, washing and drying to obtain a sediment; S1.3. Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.3 mol / L. Immerse the sediment in the citric acid solution, with the mass ratio of citric acid to sediment being 0.5:10. Under the condition of 40 °C, stir at a speed of 150 rpm for 2 h, and finally centrifuge, wash, and dry to obtain a degradable substrate; Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate, and citric acid according to a mass ratio of 7:3.5:0.7; S1.4. After fully mixing 74 parts by weight of the degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of stabilizer, and 0.8 parts by weight of rosemary extract, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material.

[0024] Example 6: A preparation method of an amino acid-based degradable material, comprising the following steps: S1.1. Dissolve calcium glutamate in deionized water to prepare a calcium glutamate solution with a concentration of 0.1 M. Add a catalyst and stir at room temperature for 30 min. Then, under nitrogen protection, transfer it to a constant temperature water bath at 90 °C and stir at a speed of 200 rpm for 4 h, cool, wash, and dry to obtain an amide compound; Among them, the catalyst is obtained by mixing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide according to a mass ratio of 1:0.5, and the catalyst accounts for 13% of the mass of calcium glutamate; S1.2. Disperse the amide compound in deionized water, where the solid-liquid ratio of the amide compound to deionized water is 1:5. Add threonine phosphate to form a mixed solution, adjust the pH of the mixed solution to 9, stir and react at 70 °C and 200 rpm for 3 h to obtain a composite solution. Then adjust the pH of the composite solution to 11, transfer it to a high-pressure reaction kettle, heat up to 150 °C, react for 12 h, centrifuge, wash, and dry to obtain a sediment; S1.3. Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.3 mol / L. Immerse the sediment in the citric acid solution, with the mass ratio of citric acid to sediment being 0.5:10. Under the condition of 40 °C, stir at a speed of 150 rpm for 2 h, and finally centrifuge, wash, and dry to obtain a degradable substrate; Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate, and citric acid according to a mass ratio of 7:3.5:0.7; S1.4. After fully mixing 79 parts by weight of the degradable substrate, 7 parts by weight of tea tree oil, 13 parts by weight of triethyl citrate, 4 parts by weight of stabilizer, and 0.8 parts by weight of rosemary extract, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material.

[0025] Comparative Example 1: Using the method of Example 2, calcium glutamate was directly used without modifying calcium glutamate through phosphothreonine and citric acid.

[0026] Comparative Example 2: Using the method of Example 2, calcium glutamate and phosphothreonine were directly used without modifying calcium glutamate and phosphothreonine through citric acid.

[0027] Comparative Example 3: Using the method of Example 2, calcium glutamate and citric acid were directly used without modifying calcium glutamate and citric acid through phosphothreonine.

[0028] The present invention provides an amino acid-based degradable material prepared from a degradable substrate. The performance index test items and test standards of the amino acid-based degradable material are as follows: The mechanical strength of the material was quantified by a tensile testing machine with a load of 30 MPa and a speed of 5 mm / min. A standard dumbbell-shaped specimen (length 75 mm, gauge section 25×4×2 mm 3 ) was used to test its initial tensile strength. It was then soaked in an acidic environment at a temperature of 37 °C and pH = 5.5 for 7 days to test its tensile strength and mass loss rate (degradation rate). An enzymatic hydrolysis solution of 1.5 wt% (lipase: protease = 2:1) was used to degrade it at a constant temperature of 37 °C for 7 days to test its tensile strength and degradation rate. Then, under the conditions of humus soil: vermiculite = 3:1 (w / w), water content of 30%, and temperature of 25 °C, it was combined with soil microorganisms for degradation for 30 days to test the tensile strength and degradation rate.

[0029] Through the above standards, the amino acid-based degradable materials prepared in Examples 1-6 and Comparative Examples 1-3 were tested, and the obtained data are shown in Table 1: Table 1 Performance data of Examples 1-6 and Comparative Examples 1-3 The above data fully show that compared with Comparative Examples 1-3, Examples 1-6 can fully demonstrate the role of the degradable substrate in the mechanical properties and degradation rate of the amino acid-based degradable material.

[0030] Since the present invention uses a degradable substrate to prepare an amino acid-based degradable material, the mechanical properties and degradation rate of the amino acid-based degradable material are effectively improved by the degradable substrate, specifically as follows: It can be seen from Examples 1-3 that as the contents of calcium glutamate, threonine phosphate and citric acid continuously increase, 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 material stability, and deposit hydroxyapatite to improve the mechanical properties. Therefore, the mechanical properties of the amino acid-based degradable material gradually increase. However, as the content of citric acid increases, the hydrophilicity of the amino acid-based degradable material increases, so the degradation rate of the material increases, and thus the mechanical properties of the amino acid-based degradable material decrease. And as the mechanical properties increase, since hydroxyapatite is not easily decomposed, the degradation rate of the amino acid-based degradable material is slower.

[0031] It can be seen from Examples 3 and 4 that as the contents of other components continuously increase, there are no obvious changes in the mechanical properties and degradation rate of the amino acid-based degradable material, 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.

[0032] It can be seen from Examples 2, 5 and 6 that as the content of the degradable substrate continuously changes, the mechanical properties and degradation rate of the amino acid-based degradable material continuously 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, so the mechanical properties gradually increase.

[0033] According to the above test experiments, it is known that the amino acid-based degradable material prepared according to Example 2 has the optimal performance, so Example 2 is taken as the optimal example. It can be seen from the comparison between Example 2 and Comparative Examples 1-3 that: In Comparative Example 1, calcium glutamate was directly used without modifying calcium glutamate with threonine phosphate and citric acid, and the mechanical properties and degradation rate of the amino acid-based degradable material were poor. Threonine phosphate forms a cross-linked structure with calcium glutamate and promotes the formation of hydroxyapatite, effectively enhancing the cohesion and mechanical strength of the material; citric acid increases the hydrophilicity of the material and helps to regulate the degradation rate. Therefore, the unmodified material shows poor mechanical properties and unsatisfactory degradation behavior due to the lack of these strengthening mechanisms, indicating the importance of the synergistic effect of multiple components in the preparation of amino acid-based degradable materials.

[0034] In Comparative Example 2, calcium glutamate and threonine phosphate were directly used without modifying calcium glutamate and threonine phosphate with citric acid. The mechanical properties and degradation rate of the amino acid-based degradable material were poor. Since threonine phosphate contains amino and carboxyl groups, it can form amide bonds with calcium glutamate, enhancing the internal cross-linking network of the material. In addition, the phosphate group can form stable chemical bonds with calcium ions in calcium glutamate, further promoting the deposition of hydroxyapatite, thereby effectively improving the mechanical strength of the material. However, due to the lack of the hydrophilic component citric acid, the degradation process of the material cannot be accelerated. This shows 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.

[0035] In Comparative Example 3, calcium glutamate and citric acid were directly used without modifying calcium glutamate and citric acid with threonine phosphate. The mechanical properties and degradation rate of the amino acid-based degradable material were poor. The cross-linking effect of threonine phosphate and the deposition of hydroxyapatite are important strengthening mechanisms for improving the mechanical strength of the material. In the absence of threonine phosphate and with the presence of the citric acid component, the degradation of the material is further accelerated, resulting in a rapid decline in the performance of the material.

[0036] In summary, through the combined action of calcium glutamate, threonine phosphate, and citric acid, the comprehensive performance of the amino acid-based degradable material can be significantly improved. Calcium glutamate provides the 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 the scope of application.

[0037] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A preparation method of an amino acid-based degradable material, characterized in that: S1.

1. Convert calcium glutamate into an amide compound under the action of a catalyst; S1.

2. Mix the amide compound with threonine phosphate to prepare a sediment; S1.

3. Further modify the sediment with citric acid to obtain a degradable substrate; S1.

4. After fully mixing and uniformly dispersing the degradable substrate, bioactive molecules, plasticizer, stabilizer and antioxidant, extrude and mold with a twin-screw extruder to obtain an amino acid-based degradable material; Among them, the degradable substrate is prepared from calcium glutamate, threonine phosphate and citric acid according to a mass ratio of 7:3-4:0.5-1; The stabilizer is one or a combination of modified starch, cellulose nanocrystals and microcrystalline cellulose.

2. The preparation method of the amino acid-based degradable material according to claim 1, characterized in that: In the above-mentioned S1.1, the specific preparation steps of the amide compound are as follows: Dissolve calcium glutamate in deionized water to prepare a calcium glutamate solution with a concentration of 0.1-0.5M, add a catalyst, stir at room temperature for 20-30 min, then under nitrogen protection, transfer it to a constant temperature water bath at 80-90 °C and stir at a speed of 200-300 rpm for 2-4 h, cool, wash and dry to obtain the amide compound.

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

4. The preparation method of the amino acid-based degradable material according to claim 1, characterized in that: In the above-mentioned S1.2, the specific preparation steps of the sediment are as follows: Disperse the amide compound in deionized water, wherein the solid-liquid ratio of the amide compound to deionized water is 1:5-10, add threonine phosphate to form a mixed solution, adjust the pH of the mixed solution to 8-9, stir and react at 60-70 °C and 100-200 rpm for 2-3 h to obtain a composite solution, then adjust the pH of the composite solution to 10.5-11, and transfer it to a high-pressure reaction kettle, heat up to 120-150 °C, react for 10-12 h, centrifuge, wash and dry to obtain the sediment.

5. The preparation method of the amino acid-based degradable material according to claim 1, wherein: In the above-mentioned S1.3, the specific preparation steps of the degradable substrate are as follows: Dissolve citric acid in deionized water to prepare a citric acid solution with a concentration of 0.1-0.3 mol / L, soak the sediment in the citric acid solution, and the mass ratio of citric acid to the sediment is 0.5-1:10, and under the condition of 40-50 °C, stir at a speed of 100-150 rpm for 1-2 h, and finally centrifuge, wash and dry to obtain the degradable substrate.

6. The preparation method of the amino acid-based degradable material according to claim 1, characterized in that: In the above-mentioned S1.4, the bioactive molecules are one or a combination of hyaluronic acid, curcumin and tea tree oil.

7. The preparation method of the amino acid-based degradable material according to claim 1, characterized in that: In the above-mentioned S1.4, the plasticizer is one or a combination of glycerol, polyethylene glycol and triethyl citrate.

8. The preparation method of the amino acid-based degradable material according to claim 1, wherein: In the above-mentioned S1.4, the antioxidant is one or a combination of vitamin E, rosemary extract and green coffee bean extract.

9. The preparation method of the amino acid-based degradable material according to claim 1, wherein: The modified starch is obtained by oxidizing starch with hydrogen peroxide.

10. The preparation method of the amino acid-based degradable material according to claim 1, characterized in that: In the above-mentioned S1.4, there are 74-83 parts by weight of the degradable substrate, 2-7 parts by weight of the bioactive molecules, 5-13 parts by weight of the plasticizer, 1-4 parts by weight of the stabilizer and 0.2-0.8 parts by weight of the antioxidant.

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