A strong and tough polypeptide biofiber and its preparation method and application

Abstract

The present application relates to the technical field of bio-based functional fiber materials, and particularly relates to a strong and tough polypeptide bio-fiber as well as a preparation method and application thereof.The strong and tough polypeptide bio-fiber comprises the following steps: S1, mixing polyglutamic acid with a surfactant to form modified polyglutamic acid; S2, preparing a base solution by using a base material with multiple hydroxyl groups on a main chain, introducing a crosslinking agent, and adding the modified polyglutamic acid into the base solution to obtain a composite spinning solution; and S3, performing spinning treatment on the composite spinning solution to process and form the strong and tough polypeptide bio-fiber.The preparation method is simple in operation, low in raw material cost and easy to obtain, can reduce the production cost and significantly improve the yield, solves the high cost problem of natural protein fiber in large-scale production, and makes the natural protein fiber have the potential for large-scale application.

Description

Technical Field

[0001] This invention relates to the field of bio-based functional fiber materials technology, specifically to a strong and tough polypeptide bio-fiber, its preparation method, and its application. Background Technology

[0002] Spider silk and silkworm silk, as typical natural protein fibers, possess unique multi-level ordered structures that endow them with excellent mechanical strength, outstanding biocompatibility, and biodegradability, making them exemplary lightweight and high-strength biomaterials. However, natural protein fibers suffer from limitations such as limited natural yield and large batch-to-batch quality fluctuations, making it difficult to meet the needs of large-scale production and standardized applications. Developing biomimetic high-performance fibers that combine structure and function has become a cutting-edge research focus in the field of biomaterials.

[0003] Regenerated protein fibers, made from renewable natural proteins, possess a soft feel, excellent wearing comfort, and moisture-wicking properties. Regenerated fibers prepared using high-performance proteins such as silk and spider silk as precursors can retain the multi-level ordered structure of the original silk at the molecular scale, thereby achieving synergistic regulation of mechanical strength and biological function, providing a feasible path to obtain designable bio-based high-performance fibers. However, the development of regenerated protein fibers faces key bottlenecks. The limited availability of high-quality protein raw materials and the immature large-scale extraction and spinning processes result in low fiber yield and high cost, severely restricting their application in high-end textiles, biomedicine, and other fields. Since proteins are essentially polypeptide chains formed by amino acids linked by peptide bonds, developing polypeptide biofibers with excellent mechanical properties and biological functions, along with their preparation methods, has become a key need to overcome the current bottlenecks. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing strong and tough polypeptide biofibers, so as to overcome the limitations of existing fibers in terms of performance, yield and cost, and meet the needs of different fields for high-performance fibers.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing strong and resilient polypeptide biofibers, comprising the following steps:

[0006] S1. Mix polyglutamic acid with a surfactant and stir continuously at room temperature to promote a complexation reaction between the two to form modified polyglutamic acid.

[0007] S2. Obtain a matrix material with multiple hydroxyl groups on its main chain, mix it evenly with a crosslinking agent to prepare a matrix solution, add the modified polyglutamic acid to the matrix solution, and continuously stir to allow the hydroxyl groups on the main chain of the matrix material to interact with the carboxyl and amino groups in the modified polyglutamic acid through hydrogen bonding to form a dynamic hydrogen bond network. The crosslinking agent is used to regulate the structure and strength of the dynamic hydrogen bond network in order to optimize the interaction force between the polyglutamic acid and the matrix material, thereby obtaining a composite spinning solution.

[0008] S3. The composite spinning solution is spun to form strong and tough polypeptide bio-fibers.

[0009] Further, in step S1, the polyglutamic acid and the surfactant are mixed in a mass ratio of 1:(0.5-2); the molecular weight of the polyglutamic acid is any value between 200,000 and 2,000,000; and the surfactant is a cationic surfactant.

[0010] Further, in step S2, the mass fraction of the matrix material in the matrix solution is any value between 5% and 10%, and the amount of crosslinking agent introduced is 0% to 50% of the mass of the matrix material; the mass fraction of the modified polyglutamic acid in the composite spinning solution is any value between 3% and 10%.

[0011] Furthermore, in step S2, the degree of alcoholysis of the matrix material is not less than 98%, and the molecular weight is any value between 85,000 and 146,000;

[0012] The matrix material is polyvinyl alcohol, and the crosslinking agent is β-cyclodextrin.

[0013] Furthermore, the method also includes pre-stretching the tough polypeptide biofiber formed in step S3, wherein the pre-stretching ratio of the pre-stretching treatment is any value from 1 to 5.

[0014] Furthermore, the strong and tough polypeptide biofiber has a tensile strength ≥100MPa, an elongation at break ≥40%, and a toughness ≥200MJ·m. -3 .

[0015] Furthermore, the tough polypeptide biofiber exhibits an antibacterial rate of ≥99% against Escherichia coli, Staphylococcus aureus, and Candida albicans within 24 hours.

[0016] Further, in step S3, during the spinning process, the spinning temperature is any value between 15℃ and 40℃, and the extrusion speed of the composite spinning solution is any value between 0.5mL / h and 10mL / h.

[0017] This application also provides a tough polypeptide biofiber, which is prepared by the above-described preparation method.

[0018] This application also provides the application of the above-mentioned strong polypeptide biofibers in surgical sutures or clothing sutures.

[0019] The beneficial effects of this invention are as follows: The method for preparing strong and tough polypeptide biofibers provided in this application optimizes the interaction between polyglutamic acid and the matrix material by modifying polyglutamic acid and introducing a crosslinking agent, thereby significantly improving the mechanical properties of the prepared polypeptide biofibers to meet the application requirements of high strength; and endowing them with excellent antibacterial properties, with an antibacterial rate of ≥99%, which can effectively inhibit the growth of Gram-negative bacteria, Gram-positive bacteria and fungi, ensuring its safety and long-term effectiveness in the medical field, such as its use as surgical sutures.

[0020] The preparation method provided in this application is simple to operate, uses low-cost and readily available raw materials, and can reduce production costs while significantly increasing yield. This solves the high-cost problem faced by natural protein fibers in large-scale production, giving them the potential for large-scale application. Furthermore, the raw materials used to prepare strong polypeptide biofibers have good biocompatibility and biodegradability, enabling them to decompose in the biological environment, reducing environmental burden and meeting the requirements of green and sustainable development.

[0021] The preparation method provided in this application can further improve the mechanical properties of the strong and tough polypeptide biofiber by pre-stretching the nascent fibers, thereby increasing its tensile strength to over 100 MPa, elongation at break ≥40%, and toughness ≥200 MJ·m. -3 .

[0022] The strong and tough polypeptide biofiber provided in this application has excellent mechanical properties, antibacterial properties and good biocompatibility. It can be widely used in many fields such as high-end textiles, medical materials and functional clothing, and can effectively solve the bottleneck problems of existing fiber materials in terms of mechanical properties, cost and sustainability.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 The FTIR spectrum of the composite spinning solution shown in Example 1 of this invention;

[0025] Figure 2 A photograph of the strong and tough polypeptide biofiber shown in Example 1 of this invention;

[0026] Figure 3 This is a SEM image of the strong and tough polypeptide biofiber shown in Example 1 of the present invention;

[0027] Figure 4 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 1 of the present invention;

[0028] Figure 5 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 2 of the present invention;

[0029] Figure 6 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 3 of the present invention;

[0030] Figure 7 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 4 of the present invention;

[0031] Figure 8 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 5 of the present invention;

[0032] Figure 9 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 7 of the present invention;

[0033] Figure 10 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 8 of the present invention;

[0034] Figure 11 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 9 of the present invention;

[0035] Figure 12 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 10 of the present invention.

[0036] Figure 13 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 11 of the present invention.

[0037] Figure 14 This is a stress-strain curve of the strong and tough polypeptide biofiber shown in Example 14 of the present invention.

[0038] Figure 15 The stress-strain curve of the polyvinyl alcohol fiber shown in Comparative Example 4 of this invention is shown.

[0039] Figure 16 This is a comparison diagram of the antibacterial effects of the fibers shown in Example 10 and Comparative Example 4 of the present invention;

[0040] Figure 17This is a diagram illustrating the antibacterial effect of the fiber shown in Example 10 of the present invention. Detailed Implementation

[0041] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] It should be noted that, unless otherwise specified, all raw materials used in this invention are commercially available.

[0043] It should be noted that the materials obtained in the embodiments of the present invention were subjected to performance testing according to the following method:

[0044] The microstructure of the fibers was analyzed using a field emission scanning electron microscope (FESEM, S4800), a solid-state nuclear magnetic resonance spectrometer (Bruker Avance Ⅲ 400 MHz), and a Fourier transform infrared spectrometer (Thermo Nicolet iS50). The tensile mechanical properties of the fibers were tested using a universal testing machine (HY-0580). The inhibition rates against Staphylococcus aureus, Escherichia coli, and Candida albicans were tested using the colony counting method (GB / T20944.2-2007).

[0045] Proteins are essentially polypeptide chains formed by amino acids linked together by peptide bonds. Experimental studies have shown that when polypeptides are blended with synthetic polymers, a dense and reversible hydrogen-bonded network structure can be formed between them. This network structure can effectively enhance the tensile strength and modulus of the material through intermolecular interactions, giving the material higher resistance to deformation under external forces. Simultaneously, it can significantly enhance the toughness of the material through energy dissipation mechanisms, preventing brittle fracture due to stress concentration. Furthermore, this network structure endows the material with excellent elastic recovery properties, allowing it to quickly return to its initial state after the external force is unloaded. Therefore, this application focuses on the field of biofibers, proposing a method for preparing strong and tough polypeptide biofibers based on modified polyglutamic acid, in order to develop novel biofiber materials with superior performance and broader application prospects.

[0046] A preferred embodiment of this application illustrates a method for preparing strong and resilient polypeptide biofibers, comprising the following steps:

[0047] S1. Mix polyglutamic acid with a surfactant and stir continuously at room temperature to promote a complexation reaction between the two to form modified polyglutamic acid.

[0048] S2. The obtained matrix material with multiple hydroxyl groups on the main chain is mixed with a crosslinking agent to form a matrix solution. Modified polyglutamic acid is added to the matrix solution and stirred continuously to allow the hydroxyl groups on the main chain of the matrix material to interact with the carboxyl and amino groups in the modified polyglutamic acid through hydrogen bonding, forming a dynamic hydrogen bond network. The structure and strength of the dynamic hydrogen bond network are controlled by the crosslinking agent to optimize the interaction force between polyglutamic acid and the matrix material, thus obtaining a composite spinning solution.

[0049] S3. The composite spinning solution is spun to form a strong and tough polypeptide bio-fiber based on modified polyglutamic acid.

[0050] In step S1, polyglutamic acid is modified by undergoing a complexation reaction with a surfactant. This complexation reaction can impart antibacterial properties to polyglutamic acid while ensuring that its spinnability is not affected, laying the foundation for the subsequent preparation of high-performance fibers.

[0051] In step S2, the matrix solution containing crosslinking agent and matrix material is thoroughly mixed with modified polyglutamic acid, allowing the hydroxyl groups on the main chain of the matrix material to interact with the carboxyl and amino groups in the modified polyglutamic acid through hydrogen bonding, forming a dynamic hydrogen bond network. Simultaneously, the crosslinking agent is used to regulate the structure and strength of the dynamic hydrogen bond network, optimizing the interaction force between polyglutamic acid and the matrix material, thereby obtaining a composite spinning solution with excellent fiber mechanical properties and spinnability.

[0052] Step S3 involves injecting the composite spinning solution into the spinning device and extruding it through a needle with a suitable aperture at a specific extrusion speed, allowing it to enter the coagulation bath to complete solvent exchange and form a strong and tough polypeptide bio-fiber with both excellent mechanical and antibacterial properties, ensuring that the fiber is formed and meets quality standards.

[0053] In one embodiment, in step S1, polyglutamic acid and a surfactant are mixed at a mass ratio of 1:(0.5-2) to ensure that the complexation reaction proceeds fully and efficiently. The molecular weight of polyglutamic acid is preferably limited to any value between 200,000 and 2,000,000. Polyglutamic acid with different molecular weights exhibits different performance in the complexation reaction. Extensive experimental studies have found that polyglutamic acid within this molecular weight range, after complexation with a surfactant, can better balance antibacterial and spinnability properties. The surfactant is preferably a cationic surfactant. The positive charge of the cationic surfactant can effectively interact with the negatively charged groups on the polyglutamic acid molecule through electrostatic interaction, thereby promoting the complexation reaction. By clearly defining the molecular weight of polyglutamic acid, the mass ratio range with the surfactant, and the type of surfactant, stable and suitable conditions are created for the complexation reaction, allowing it to proceed smoothly. This results in the modified polyglutamic acid possessing ideal antibacterial properties, effectively inhibiting the growth and reproduction of various common bacteria, while maintaining good spinnability. In some embodiments, the polyglutamic acid is preferably γ-polyglutamic acid (γ-PGA). γ-PGA exhibits better reactivity and stability in complexation reactions. The surfactant can be selected from one of the following: hexadecyltrimethylammonium chloride (CTAC), hexadecyltrimethylammonium bromide (CTAB), benzalkonium chloride (BAC), cetrimonium bromide, ethyl lauroyl arginine (ELA), or pyridinium salts. Comparative experiments have shown that ethyl lauroyl arginine can achieve a better balance between antibacterial and spinnable properties in modified polyglutamic acid; therefore, ethyl lauroyl arginine (ELA) is preferred as the surfactant. In this embodiment or other embodiments, in step S2, the mass fraction of the matrix material in the matrix solution is limited to 5%–10% by mass percentage to ensure complete dissolution and provide a stable reaction system. The amount of crosslinking agent introduced is 0%–5% of the mass fraction of the matrix material. Appropriate introduction of the crosslinking agent can regulate the structure and strength of the dynamic hydrogen bond network, avoiding adverse effects on the final material's performance due to excessive or insufficient addition. The matrix solution and modified polyglutamic acid were mixed in a specific ratio, with the mass fraction of modified polyglutamic acid in the composite spinning solution being 3%–10%. This ensured the compatibility and interaction between the modified polyglutamic acid and the matrix material, allowing them to achieve optimal synergistic effects in the composite spinning solution. By precisely controlling the concentration of the matrix material in the matrix solution, the amount of crosslinking agent added, and the mass fraction of modified polyglutamic acid in the composite spinning solution, extremely favorable conditions were created for the formation of a dynamic hydrogen bond network. This effectively optimized the intermolecular interactions and enhanced the intermolecular binding forces, thus formulating a high-performance composite spinning solution and laying the foundation for the subsequent preparation of high-performance fiber materials.

[0054] In one embodiment, in step S2, the degree of alcoholysis of the matrix material is not less than 98% to ensure that the molecular chain of the matrix material has a sufficient number of active hydroxyl groups to fully interact with the modified polyglutamic acid. Simultaneously, the molecular weight of the matrix material needs to be controlled within the range of 85,000 to 146,000 to ensure that the matrix material can form a structurally stable and high-performance composite system, i.e., a composite spinning solution system, when combined with the modified polyglutamic acid. By limiting the degree of alcoholysis and molecular weight range of the matrix material, suitable physicochemical properties are ensured, thereby enabling better interaction with the modified polyglutamic acid and forming a high-performance composite system. In this embodiment or other embodiments, the matrix material is preferably polyvinyl alcohol (PVA). Polyvinyl alcohol is widely available and inexpensive, and the large number of hydroxyl groups in its molecular structure gives it good hydrophilicity and reactivity, enabling it to form a strong interaction with the modified polyglutamic acid, which is beneficial to improving the performance of the composite system. The crosslinking agent can be cyclodextrin, and preferably β-cyclodextrin (β-CD). β-Cyclodextrin has a unique cyclic molecular structure, and its cavity can encapsulate the matrix material and modified polyglutamic acid molecules, thereby effectively regulating the formation and structure of the dynamic hydrogen bond network, and thus significantly improving the mechanical properties and other related properties of the material, making the composite system more in line with the requirements of high-performance fibers.

[0055] In one embodiment, in step S3, during the spinning process, the spinning temperature is limited to the range of 15℃-40℃ to ensure that the components in the composite spinning solution maintain good dispersion and suitable viscosity. This avoids problems such as poor flowability and difficulty in extrusion due to excessively low temperatures, and thermal degradation or uneven phase separation due to excessively high temperatures, thus providing a stable temperature environment for the smooth formation of nascent fibers. The extrusion speed of the composite spinning solution is any value between 0.5mL / h and 10mL / h, allowing the composite spinning solution to be extruded from the spinneret in a stable and continuous manner and enter the coagulation bath to complete the solvent exchange and fiber formation process. This ensures that the formed nascent fibers are of uniform quality and avoids defects such as rough fiber surface and internal pores caused by excessively fast extrusion speeds, or uneven fiber diameter and low production efficiency caused by excessively slow extrusion speeds. By precisely limiting the range of spinning temperature and extrusion speed, the smooth formation of nascent fibers of uniform quality by the composite spinning solution during the spinning process is guaranteed.

[0056] In one embodiment, the preparation method may further include pre-stretching the strong and tough polypeptide biofiber formed in step S3, wherein the pre-stretching ratio is limited to the range of 1 to 5. Pre-stretching involves applying a certain stretching force to orient the fiber molecular chains along the stretching direction, thereby improving the crystallinity and orientation of the fiber. Within this stretching ratio range, the fiber molecular structure can achieve an orderly and sufficient arrangement, avoiding both insufficient mechanical properties due to a too small stretching ratio and excessive defects and stress concentration within the fiber due to an excessively large stretching ratio, which could lead to fiber breakage. After pre-stretching, the final strong and tough polypeptide biofiber possesses excellent mechanical properties, with a tensile strength ≥100 MPa, capable of withstanding significant external forces without breakage; a breaking elongation ≥40%, exhibiting good flexibility and deformability; and a toughness ≥200 MJ·m. -3 This allows the fiber to absorb a large amount of energy during deformation under stress, resulting in excellent impact resistance. Consequently, the mechanical properties of the resulting strong and tough polypeptide biofiber meet predetermined standards, fully satisfying the diverse needs of different application scenarios for fiber strength, flexibility, and impact resistance. This lays the foundation for the widespread application of this strong and tough polypeptide biofiber in biomedicine, textiles, and composite materials. In other embodiments, the resulting strong and tough polypeptide biofiber also exhibits excellent antibacterial properties. Against common pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Candida albicans, the antibacterial rate consistently reaches 99% or higher within 24 hours. This antibacterial effect is mainly attributed to the modified polyglutamic acid component, which precisely disrupts the bacterial cell wall or cell membrane structure, interfering with the normal physiological metabolic processes of bacteria, thereby achieving a highly effective inhibition of bacterial growth and reproduction. The excellent antibacterial properties give this strong and tough polypeptide biofiber broad application prospects in fields with extremely high hygiene and safety requirements, such as biomedicine.

[0057] This application also provides a tough polypeptide biofiber prepared by the above-described preparation method.

[0058] This application also provides the application of the aforementioned strong and tough polypeptide biofiber in surgical sutures or clothing sutures. This strong and tough polypeptide biofiber possesses excellent mechanical and antibacterial properties. In surgical suturing, it can effectively prevent suture breakage, ensuring the smooth progress of the operation and significantly reducing the risk of postoperative infection, providing strong support for patient recovery. In clothing applications, it can ensure that garments are less prone to unraveling during wear and washing, improving garment durability, inhibiting bacterial growth, reducing odor, and providing wearers with a healthier and more comfortable experience.

[0059] Example 1

[0060] S1. Weigh 20g of γ-polyglutamic acid (PGA), which has a molecular weight of 2 million. Dissolve the PGA in 1L of deionized water, mix thoroughly, and prepare a 2% (w / w) PGA solution. Separately weigh 20g of lauroyl arginine ethyl ester, dissolve it in 1L of deionized water, and prepare a 2% (w / w) ELA solution. Then, slowly add the prepared PGA solution dropwise to the lauroyl arginine ethyl ester solution, and mechanically stir at room temperature for 2 hours to promote a complexation reaction between PGA and lauroyl arginine ethyl ester, forming a complex solution. Filter the complex solution, collect the precipitate, and ultrasonically clean the precipitate with deionized water to remove free lauroyl arginine ethyl ester and unreacted PGA. After repeated ultrasonic cleaning three times, collect the lumpy product and freeze-dry it under vacuum for 48 hours. The lumpy product was then ground to obtain a white modified polyglutamic acid powder, denoted as PEA powder.

[0061] S2. Weigh 1.0 g of polyvinyl alcohol (PVA) with a molecular weight of 130,000 and a degree of alcoholysis of 99%. Add the weighed PVA to 9.0 g of DMSO (dimethyl sulfoxide) and stir at 90°C for 2 hours to completely dissolve the PVA, forming a PVA solution. After the PVA solution cools naturally to room temperature, add 0.2 g of β-cyclodextrin to form a matrix solution, ensuring the mass fraction of the crosslinking agent in the matrix solution is approximately 2%. Continue stirring to ensure that the β-cyclodextrin is fully dispersed and uniformly mixed in the matrix solution. Subsequently, weigh 1.0 g of PEA powder and dissolve it in 9.0 g of DMSO to obtain a 10% PEA solution. Subsequently, the matrix solution containing polyvinyl alcohol and β-cyclodextrin was mixed with the PEA solution at a mass ratio of 1:2, so that the mass fraction of modified polyglutamic acid in the composite spinning solution was 6.67%. Continuous stirring was performed using a magnetic stirrer to allow the hydroxyl groups on the polyvinyl alcohol backbone to interact with the carboxyl and amino groups in the PEA powder through hydrogen bonding, gradually forming a dynamic hydrogen bond network. The structure and strength of this dynamic hydrogen bond network were then controlled using β-cyclodextrin to optimize the interaction between the modified polyglutamic acid and polyvinyl alcohol. After thorough stirring and reaction, a uniform and stable composite spinning solution was finally obtained. The Fourier transform infrared (FTIR) spectra of this composite spinning solution and its precursor materials are as follows: Figure 1 As shown.

[0062] S3. Transfer the composite spinning solution to a specially designed spinning device, using a needle with an inner diameter of 0.6 mm as the spinning nozzle. At 25°C, extrude the composite spinning solution from the needle at an extrusion rate of 10 mL / h. The extruded spinning solution directly enters a pre-prepared methanol coagulation bath. Methanol, acting as a coagulant, rapidly diffuses the solvent DMSO from the spinning solution, simultaneously solidifying components such as polyvinyl alcohol and modified polyglutamic acid, thereby forming strong and tough polypeptide biofibers, such as... Figure 2 As shown.

[0063] like Figure 3 The image shown is a SEM image of this strong polypeptide biofiber. Figure 3 As can be seen, the tough polypeptide biofiber based on antibacterial modified polyglutamic acid prepared in Example 1 is a continuous and uniform cylindrical shape with obvious wavy or wrinkled texture on the surface, but without obvious breakage or defects. Five segments of the tough polypeptide biofiber were randomly selected for performance testing, and the results are as follows: Figure 4 As shown.

[0064] Example 2

[0065] The difference between this embodiment and Embodiment 1 is that in step S2, 0.1 g of β-cyclodextrin is added to the polyvinyl alcohol solution, making the mass fraction of the crosslinking agent in the matrix solution approximately 1%; ultimately, a glossy and tough polypeptide biofiber is obtained. The mechanical property test results of this tough polypeptide biofiber are as follows: Figure 5 As shown.

[0066] Example 3

[0067] The difference between this embodiment and Embodiment 1 is that in step S2, 0.3g of β-cyclodextrin is added to the polyvinyl alcohol solution, making the mass fraction of the crosslinking agent in the matrix solution approximately 3%; ultimately, a glossy and tough polypeptide biofiber is obtained. The mechanical property test results of this tough polypeptide biofiber are as follows: Figure 6 As shown.

[0068] Example 4

[0069] The difference between this embodiment and Embodiment 1 is that in step S2, 0.4 g of β-cyclodextrin is added to the polyvinyl alcohol solution, making the mass fraction of the crosslinking agent in the matrix solution approximately 4%; ultimately, a glossy and tough polypeptide biofiber is obtained. The mechanical property test results of this tough polypeptide biofiber are as follows: Figure 7 As shown.

[0070] Example 5

[0071] The difference between this embodiment and Embodiment 1 is that in step S2, 0.5g of β-cyclodextrin is added to the polyvinyl alcohol solution, making the mass fraction of the crosslinking agent in the matrix solution approximately 5%; ultimately, a glossy and tough polypeptide biofiber is obtained. The mechanical property test results of this tough polypeptide biofiber are as follows: Figure 8 As shown.

[0072] Example 6

[0073] The difference between this embodiment and Example 1 is that in step S2, β-cyclodextrin is not added to the polyvinyl alcohol solution, i.e., a pure PVA solution is obtained; finally, a glossy and tough polypeptide bio-fiber is obtained.

[0074] The spinnability of the composite spinning solutions prepared in Examples 1-6 was tested. The results showed that when no crosslinking agent was introduced or only a small amount was introduced (i.e., the mass fraction of the crosslinking agent in the matrix solution did not exceed 1%), the matrix solution could be uniformly mixed with the PEA matrix solution to form a composite spinning solution, and the composite spinning solution could be spun into fibers smoothly. However, the composite spinning solution was prone to gelation, and the spinning effect gradually deteriorated over time. When the mass fraction of the crosslinking agent in the matrix solution was in the range of 1% to 3%, the gelation phenomenon of the composite spinning solution was improved, the spinning effect was significantly improved, and uniform fibers could be spun continuously and stably. However, when the mass fraction of the crosslinking agent in the matrix solution exceeded 3%, the viscosity of the composite spinning solution became too high, which led to a decrease in spinning effect, uneven fibers, and a decline in fiber performance. Simultaneously, combined with... Figures 4-8 It is evident that adjusting the amount of crosslinking agent introduced significantly affects the properties of polypeptide biofibers. When the amount of crosslinking agent introduced reaches a specific value, the composite spinning solution achieves optimal spinnability, and the resulting strong and tough polypeptide biofibers exhibit excellent mechanical properties, possessing higher strength and toughness. However, with the continuous increase in the amount of crosslinking agent introduced, the spinnability of the composite spinning solution gradually deteriorates, and the mechanical properties of the strong and tough polypeptide biofibers also decline. This is because the crosslinking agent plays a connecting and stabilizing role in the matrix solution. An appropriate amount of crosslinking agent can optimize the molecular structure and rheological properties in the matrix solution, thereby improving the spinning effect and fiber properties; however, when the crosslinking agent is excessive, it leads to excessive crosslinking between molecules in the matrix solution, resulting in excessive viscosity, which in turn damages the spinnability of the formed composite spinning solution, ultimately affecting fiber formation and quality. Therefore, in the technical solution provided in this application, when the mass fraction of the crosslinking agent in the matrix solution is approximately 2%, the spinnability of the composite spinning solution and the mechanical properties of the prepared strong and tough polypeptide biofibers can both reach a relatively ideal state.

[0075] Example 7

[0076] The difference between this embodiment and Embodiment 1 is that in step S4, the strong and tough polypeptide biofiber formed in step S3 is pre-stretched, and the pre-stretch ratio is 1, i.e., pre-stretched by 100%; finally, a glossy and strong polypeptide biofiber is obtained. The mechanical property test results of this strong and tough polypeptide biofiber are as follows: Figure 9 As shown.

[0077] Example 8

[0078] The difference between this embodiment and Embodiment 1 is that in step S4, the strong and tough polypeptide biofiber formed in step S3 is pre-stretched, and the pre-stretch ratio is 2, i.e., pre-stretched by 200%; finally, a strong and tough polypeptide biofiber is obtained. The mechanical property test results of this strong and tough polypeptide biofiber are as follows: Figure 10 As shown.

[0079] Example 9

[0080] The difference between this embodiment and Embodiment 1 is that in step S4, the strong and tough polypeptide biofiber formed in step S3 is pre-stretched, and the pre-stretch ratio is 3, i.e., pre-stretched by 300%; finally, a strong and tough polypeptide biofiber is obtained. The mechanical property test results of this strong and tough polypeptide biofiber are as follows: Figure 11 As shown.

[0081] Example 10

[0082] The difference between this embodiment and Embodiment 1 is that in step S4, the strong and tough polypeptide biofiber formed in step S3 is pre-stretched, and the pre-stretch ratio is 4, i.e., pre-stretched by 400%; finally, a strong and tough polypeptide biofiber is obtained. The mechanical property test results of this strong and tough polypeptide biofiber are as follows: Figure 12 As shown.

[0083] Example 11

[0084] The difference between this embodiment and Embodiment 1 is that in step S4, the strong and tough polypeptide biofiber formed in step S3 is pre-stretched, and the pre-stretch ratio is 5, i.e., pre-stretched by 500%; finally, a strong and tough polypeptide biofiber is obtained. The mechanical property test results of this strong and tough polypeptide biofiber are as follows: Figure 13 As shown.

[0085] Comparing Example 1 with Examples 7-11, it can be seen that the strong and tough polypeptide biofiber prepared in Example 1, without pre-stretching treatment, exhibits typical low strength and high ductility mechanical characteristics. Figure 4 It is known that the tensile strength of this tough polypeptide bio-fiber is only about 45 MPa, while its elongation at break exceeds 700%, indicating that the fiber only breaks under significant deformation, but the tensile force it can withstand is relatively small. Figures 9-13As shown, when nascent fibers are pre-stretched, their mechanical behavior is altered, and this change is significant with increasing pre-stretch ratio. During pre-stretching, the polyvinyl alcohol and polyglutamic acid molecular chains within the fiber are subjected to external forces, forcing them to orient themselves in an orderly manner along the stretching direction. This effectively reduces the random coiling of the molecular chains, promoting a more regular arrangement and increasing the content of crystalline or ordered regions within the fiber. The increased content of crystalline or ordered regions significantly enhances the intermolecular forces. This increased intermolecular force improves the overall tensile strength of the fiber at the microscopic level. Therefore, with increasing pre-stretch ratio, the tensile strength and other mechanical properties of the fiber are significantly improved, enabling the fiber to withstand greater tensile forces without breaking, exhibiting superior mechanical properties.

[0086] Example 12

[0087] The difference between this embodiment and Embodiment 1 is that in step S2, the PEA solution and the PVA solution containing about 2% β-CD are mixed at a mass ratio of 3:2; finally, strong and tough polypeptide biofibers are obtained.

[0088] Example 13

[0089] The difference between this embodiment and Embodiment 1 is that in step S2, the PEA solution and the PVA solution containing 2% β-CD are mixed at a mass ratio of 3:1; finally, strong and tough polypeptide biofibers are obtained.

[0090] Example 14

[0091] The difference between this embodiment and Embodiment 1 is that in step S1, 1g of γ-polyglutamic acid with a molecular weight of 2 million is weighed. The weighed γ-polyglutamic acid is dissolved in 9g of deionized water, mixed evenly, and a γ-polyglutamic acid solution is prepared for later use.

[0092] S2. Weigh 1.0 g of polyvinyl alcohol (PVA) with a molecular weight of 130,000 and a degree of alcoholysis of 99%. Add the weighed PVA to 9.0 g of DMSO (dimethyl sulfoxide) and stir at 90°C for 2 hours to completely dissolve the PVA, forming a PVA solution. After the PVA solution has cooled naturally to room temperature, mix the above PVA solution with a γ-polyglutamic acid solution at a mass ratio of 1:1 and stir continuously with a magnetic stirrer to allow the hydroxyl groups on the main chain of PVA to interact with the carboxyl and amino groups in the PEA powder through hydrogen bonding, gradually forming a dynamic hydrogen bond network. After thorough stirring and reaction, a uniform and stable composite spinning solution is finally obtained.

[0093] The final product was a polypeptide biofiber. The mechanical properties of this polypeptide biofiber were tested as follows: Figure 14 As shown.

[0094] The performance of the tough polypeptide biofibers prepared in Examples 1, 12-14 above was tested, and the comparison results are shown in Table 1.

[0095]

[0096] As shown in Table 1 above, modification of polyglutamic acid not only endows it with antibacterial function but also imparts certain hydrophobic properties. When this hydrophobic antibacterial modified polyglutamic acid is blended with polyvinyl alcohol and β-cyclodextrin is introduced to prepare polypeptide biofibers, the mechanical properties of the polypeptide biofibers can be significantly improved through dynamic hydrogen bonding networks and physical cross-linking networks. Furthermore, a higher proportion of modified polyglutamic acid can increase the hydrophobic microdomains in the composite spinning solution system, thereby enhancing the strength of the physical cross-linking network and potentially inducing more complex molecular self-assembly structures, thus improving the tensile strength of the polypeptide biofibers. In addition, even with a high content of antibacterial modified polyglutamic acid, its hydrophobicity and the effect of β-cyclodextrin effectively maintain the uniformity and flowability of the composite spinning solution, avoiding phase separation or gelation caused by excessively high concentrations of antibacterial modified polyglutamic acid, ensuring that the high content of antibacterial modified polyglutamic acid is uniformly dispersed and fully exerts its reinforcing effect.

[0097] Comparative Example 1

[0098] Natural γ-polyglutamic acid powder with a molecular weight of 300 kDa was added to deionized water and magnetically stirred at 25°C for 12 h to prepare a uniform spinning solution with a mass fraction of 15%. After the solution was allowed to stand at 4°C for 24 h to remove bubbles, it was loaded into a 10 mL syringe and fed through a stainless steel spinneret with an inner diameter of 200 μm and an aspect ratio of 10:1 at a rate of 0.5 mL / min. -1 The extrusion rate is injected into a flow velocity of 2 cm·s. -1 Nascent fibers were formed in an acetone coagulation bath. After being drawn 1 m in the coagulation bath, the nascent fibers were guided by rollers into a water washing tank and immersed for 30 min to remove residual solvent. Subsequently, the wet fibers were uniaxially stretched at 3 times their initial length at room temperature, fixed on a glass plate, and dried in a vacuum drying oven at 40 °C for 24 h to obtain γ-PGA fibers with a diameter of approximately 150 μm.

[0099] Comparative Example 2

[0100] Commercially available Vicryl® absorbable sutures (Ethicon, Inc., USA, model: Vicryl 3-0, with needle).

[0101] Comparative Example 3

[0102] Chitosan with a degree of deacetylation ≥85% and a molecular weight of approximately 200 kDa was added to a deionized aqueous solution containing 2 wt% glacial acetic acid at a mass ratio of 3:7 with polyvinyl alcohol (molecular weight between 89,000 and 98,000). The solution was stirred at 80°C for 6 hours until completely dissolved, preparing a homogeneous spinning solution with a total solid content of 12 wt%. After degassing the spinning solution at 60°C for 12 hours, the solution was fed through a spinneret with an inner diameter of 180 μm at a rate of 0.3 mL / min. -1 The fibers were extruded at a flow rate into a coagulation bath consisting of 5 wt% NaOH and 70 vol% ethanol to form nascent fibers. After being washed with water until neutral, the nascent fibers were wet-stretched at 25°C with a stretch ratio of 2.5. They were then suspended in a sealed container and exposed to glutaraldehyde vapor at 25°C and 60% relative humidity for 2 hours for crosslinking. Finally, the fibers were vacuum-dried at 40°C for 12 hours to obtain chitosan / polyvinyl alcohol (CS / PVA) composite antibacterial fibers with a diameter of approximately 160 μm.

[0103] Comparative Example 4

[0104] 1.0 g of polyvinyl alcohol (PVA) with a molecular weight of 130,000 was weighed and added to 9.0 g of DMSO (dimethyl sulfoxide). The mixture was stirred at 90°C for 2 hours to completely dissolve the PVA, forming a PVA solution. After the PVA solution cooled naturally to room temperature, 0.2 g of β-cyclodextrin was added to the PVA solution to make the mass fraction of the crosslinking agent in the solution approximately 2%. The mixture was then thoroughly mixed to prepare a spinning solution. At 25°C, the spinning solution was extruded from a needle into a methanol coagulation bath at an extrusion rate of 10 mL / h to form PVA fibers. The mechanical properties of the PVA fibers were tested as follows: Figure 15 As shown.

[0105] The mechanical properties and antibacterial rate of the fiber materials prepared in Example 10 and Comparative Examples 1-4 were tested, and the results are shown in Table 2.

[0106]

[0107] As shown in Table 2, compared with the three fibers provided in Comparative Examples 1-4, the strong and tough polypeptide biofiber prepared in Example 10 has superior mechanical properties, with a tensile strength ≥100MPa, elongation at break ≥40%, and toughness ≥200MJ·m. -3 All of these significantly outperformed unmodified γ-PGA fibers, polyvinyl alcohol fibers, commercially available Vicryl® sutures, and chitosan / polyvinyl alcohol composite fibers. Furthermore, as... Figure 16-17As shown, the tough polypeptide biofiber prepared in Example 10, compared with the pure polyvinyl alcohol fiber in Comparative Example 4, exhibited broad-spectrum and highly efficient inhibition of Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and fungi (Candida albicans) in terms of antibacterial properties. The antibacterial rate after 24 hours was ≥99%, which was far superior to that of pure polyvinyl alcohol fiber.

[0108] Therefore, the strong and tough polypeptide biofiber prepared by the preparation method provided in this application can have both high mechanical reliability and broad-spectrum and long-lasting antibacterial properties, and can be used in applications such as surgical suturing or clothing fabrics in high-risk infection environments.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing strong and tough polypeptide biofibers, characterized in that, Includes the following steps: S1. Polyglutamic acid and surfactant are mixed and stirred continuously at room temperature to promote a complexation reaction between the two to form modified polyglutamic acid; wherein, the polyglutamic acid and surfactant are mixed in a mass ratio of 1:(0.5-2); the molecular weight of the polyglutamic acid is any value between 200,000 and 2,000,000; and the surfactant is lauroyl arginine ethyl ester. S2. Obtain a matrix material with multiple hydroxyl groups on its main chain, mix it evenly with a crosslinking agent to prepare a matrix solution, add the modified polyglutamic acid to the matrix solution, and continuously stir to allow the hydroxyl groups on the main chain of the matrix material to interact with the carboxyl and amino groups in the modified polyglutamic acid through hydrogen bonding, forming a dynamic hydrogen bond network. The crosslinking agent is used to regulate the structure and strength of the dynamic hydrogen bond network to optimize the interaction between the polyglutamic acid and the matrix material, thereby obtaining a composite spinning solution; wherein, the degree of alcoholysis of the matrix material is not less than 98%, and the molecular weight is any value between 85,000 and 146,000; The matrix material is polyvinyl alcohol, and the crosslinking agent is β-cyclodextrin; S3. The composite spinning solution is spun to form strong and tough polypeptide bio-fibers.

2. The preparation method according to claim 1, characterized in that, In step S2, the matrix material in the matrix solution has a mass fraction of 5% to 10% by mass percentage, and the amount of crosslinking agent introduced is 0% to 50% of the mass of the matrix material; the modified polyglutamic acid in the composite spinning solution has a mass fraction of 3% to 10%.

3. The preparation method according to claim 1, characterized in that, It also includes pre-stretching the strong polypeptide biofiber formed in step S3, wherein the pre-stretching ratio of the pre-stretching treatment is any value from 1 to 5.

4. The preparation method according to claim 3, characterized in that, The strong and tough polypeptide biofiber has a tensile strength ≥100MPa, an elongation at break ≥40%, and a toughness ≥200MJ·m. -3 .

5. The preparation method according to claim 3, characterized in that, The tough polypeptide biofiber exhibits an antibacterial rate of ≥99% against Escherichia coli, Staphylococcus aureus, and Candida albicans within 24 hours.

6. The preparation method according to claim 1, characterized in that, In step S3, during the spinning process, the spinning temperature is any value between 15℃ and 40℃, and the extrusion speed of the composite spinning solution is any value between 0.5mL / h and 10mL / h.

7. A strong and resilient polypeptide bio-fiber, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

8. The application of the strong polypeptide biofiber of claim 7 in surgical sutures or clothing sutures.

Images