A method for preparing a toughened bio-protein fiber based on a two-stage crosslinking system

Abstract

The application discloses a method for preparing a toughened biological protein fiber based on a two-stage crosslinking system. The method comprises the following steps: S1, adding a crosslinking agent drop by drop into a protein solution to perform primary crosslinking, so as to form a protein spinning solution with a certain crosslinking network; S2, extruding the protein spinning solution through a syringe pump, extruding the protein spinning solution into a coagulation bath containing a certain concentration of crosslinking agent through a multi-channel microfluidic / wet spinning chip, and then performing secondary crosslinking; S3, performing post-stretching on the fiber through a stretching roller to obtain a toughened biological protein fiber with a certain stress and strain; and the toughening is performed in the following three ways: adding a toughening agent in the coagulation bath; passing the fiber into a toughening agent solution to perform toughening during the post-stretching process; and the combination of the above two methods. The application prepares a biological protein fiber with enhanced toughness through the combination of primary crosslinking and secondary crosslinking and the three toughening methods, and provides a high-performance material for the application of natural biological macromolecular fibers in the biomedical field.

Description

Technical Field

[0001] This invention relates to the field of bio-protein fiber preparation technology, and in particular to a method for preparing toughened bio-protein fibers based on a secondary cross-linking system. Background Technology

[0002] It is well known that fibers prepared from natural biomacromolecules such as proteins and polysaccharides possess excellent biocompatibility, renewability, and biodegradability. However, compared to synthetic polymer fibers, the mechanical properties of natural biomacromolecule fibers still cannot meet specific requirements in some applications. Currently, the modification of natural biomacromolecules has become one of the directions of technological research and development, mainly including physical modification and chemical modification. Physical modification mainly includes blending, doping, and heat treatment. This method requires high compatibility between the components; if the components are incompatible, the performance of the blended composite material will not be significantly improved. Chemical modification refers to a class of modification methods that change the types and arrangements of atoms or atomic groups on polymer chains through chemical reactions. These methods mainly include crosslinking, grafting, block polymerization, and chain extension, among which crosslinking modification is widely used in the modification of natural biomacromolecules. Crosslinking can react linear or branched polymers to form a network structure, thereby enhancing the stability and mechanical properties of the material.

[0003] Wet spinning is a method for preparing fibers through solution spinning. The basic steps of wet spinning include preparing the spinning solution, extruding the solution from a spinneret or injection needle to form a fiber stream, and then coagulating or undergoing a chemical reaction in a coagulation bath to form nascent fibers. These nascent fibers are then stretched to form fibers with specific mechanical properties, which can be applied to materials that cannot be melt-spun, such as natural biomolecules. Wet spinning technology has, to some extent, expanded the processing and application range of natural biomolecule fibers. However, current wet spinning technology still has drawbacks, such as insufficient strength of protein fibers and the need to use high doses of toxic crosslinking agents. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing toughened bio-protein fibers based on a two-stage crosslinking system, thereby solving the problems of insufficient strength and toughness of bio-protein fibers and the need to use high doses of toxic crosslinking agents in the prior art.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] According to a first aspect of the present invention, a method for preparing toughened bio-protein fibers based on a secondary crosslinking system is provided, comprising the following steps: S1: adding a crosslinking agent dropwise to a protein solution to perform primary crosslinking, forming a protein spinning solution with a certain crosslinking network; wherein, the protein is one or more selected from bovine serum albumin, elastin-like protein, silk fibroin, soybean protein, and corn protein; the concentration of the protein solution is 3-600 mg / mL; the crosslinking agent for primary crosslinking includes glutaraldehyde, PEG dialdehyde, and genipin; the volume ratio of the crosslinking agent to the protein solution is (0.05-1):100; the concentration of the crosslinking agent component in the primary crosslinking agent solution is 0.5%-30%; S2: extruding the protein spinning solution obtained in step S1 through an injection pump, and extruding it through a multi-channel microfluidic / wet spinning chip into a solution containing a certain crosslinking network. Secondary crosslinking is performed in a coagulation bath containing a crosslinking agent; wherein the coagulation bath is an aqueous solution containing a dehydrating agent and a crosslinking agent; the dehydrating agent is one or more of methanol, ethanol, and polyols; the crosslinking agent for secondary crosslinking includes glutaraldehyde, PEG dialdehyde, and genipin; the concentration of the crosslinking agent component in the coagulation bath is 0.5% to 10%; S3: After secondary crosslinking in the coagulation bath, the fiber is post-stretched by a stretching roller and wound on a collecting roller to form a toughened bioprotein fiber with certain stress and strain; wherein toughening is performed in the following three ways: a) adding a toughening agent to the coagulation bath in step S2; b) passing the fiber through a toughening agent solution for toughening during the post-stretching process in step S3; c) a combination of the above two methods; the toughening agent is one or more of glycerol, ethyl acetate, ectoine, and dioctyl phthalate.

[0007] Preferably, in step S2, the concentration of the toughening agent in the coagulation bath is 0-10%; more preferably, it is 4%-10%.

[0008] Preferably, in step S3, the concentration of the toughening agent in the toughening agent solution is 0.5% to 50%; more preferably, it is 1% to 15%; and most preferably, it is 10%.

[0009] Preferably, the concentration of the protein solution is 3–600 mg / mL, more preferably 300–500 mg / mL; and most preferably 400 mg / mL. If the concentration is too low, the fiber cannot be formed; if the concentration is too high, the spinning solution is too viscous and cannot be spun normally.

[0010] The crosslinking agent for the primary crosslinking is preferably glutaraldehyde, PEG-dialdehyde, or genipin; more preferably glutaraldehyde.

[0011] Preferably, in step S1, the concentration of the crosslinking agent component in the primary crosslinking agent solution is 0.5%–30%; more preferably 5%–20%; and most preferably 10%. The volume ratio of the crosslinking agent to the protein solution is (0.05–1):100, more preferably (0.1–0.4):100, and most preferably 0.2:100. According to research based on the present invention, if the crosslinking concentration of the primary crosslinking agent or the concentration of the crosslinking agent component in the primary crosslinking agent solution is too high, excessive reaction will occur with the protein spinning solution, leading to the appearance of a gel-like substance and preventing normal spinning.

[0012] The primary crosslinking described in this invention involves adding a crosslinking agent dropwise to a protein solution to form a protein spinning solution with a certain crosslinking network. Preferably, in step S1, the volume of the crosslinking agent added dropwise is 5–200 μL. By controlling the volume of the crosslinking agent solution added dropwise, the rate of the chemical reaction is avoided from becoming too fast, which could cause the solution to become gel-like.

[0013] Preferably, in step S2, the multi-channel microfluidic / wet spinning chip is a structural unit with a central channel connected to a stainless steel microtube or a glass conical microtube connector, and multiple branch channels evenly distributed in the same direction inside the chip. The number of branch channels is 2 to 100 channels; more preferably 2 to 50 channels; and most preferably 10 to 20 channels. Different numbers of channels result in different numbers of fibers.

[0014] Preferably, in step S2, the flow rate of the injection pump is 0.5–500 μL / min; more preferably 0.5–400 μL / min; and most preferably 50–300 μL / min. It should be understood that the flow rate determines whether the fiber can be properly formed. Too low a flow rate will prevent the spinning solution from being extruded or the fiber will be too fine to be stretched further; too high a flow rate will cause the spinning solution to directly contact the bottom of the coagulation bath, preventing proper collection.

[0015] The crosslinking agent for the secondary crosslinking is preferably glutaraldehyde, PEG-dialdehyde, or genipin; more preferably glutaraldehyde.

[0016] The toughening agent is preferably one or more of glycerol, ethyl acetate, ectoine, and dioctyl phthalate; more preferably glycerol.

[0017] Preferably, in step S2, the concentration of the dehydrating agent in the coagulation bath is 50%–99.5%, the concentration of the crosslinking agent component in the coagulation bath is 0.5%–10%, and the concentration of the toughening agent is 0–10%. Different concentrations of crosslinking agent will produce fibers with different strengths. When the concentration is too low, the fiber strength decreases; when it is too high, the fiber is too brittle and easily breaks.

[0018] The stretching rollers in this invention are preferably a set of stainless steel rollers with the same diameter and adjustable rotation speed. The diameter of the stainless steel rollers is preferably 3–20 cm; more preferably 5–10 cm; and most preferably 7.5 cm.

[0019] Preferably, in step S3, the rotational speed of the stretching roller is 1–100 rpm; more preferably, it is 3–40 rpm. The collecting roller has the same diameter as the stretching roller and can fix the paper tube on the central shaft, rotating synchronously with the collecting roller. Different stretching roller rotation speeds result in different stretching ratios, and different stretching ratios result in different fiber mechanical strengths. The higher the stretching ratio, the greater the stress and the smaller the strain.

[0020] According to a second aspect of the present invention, a toughened bio-protein fiber prepared by the above-described preparation method is provided.

[0021] The fibers prepared by this invention can be woven into various textiles through a weaving process and applied to biomaterials such as surgical sutures, biological patches, and cardiac stents.

[0022] According to the present invention, a method for preparing toughened bio-protein fibers based on a two-stage crosslinking system is provided. First, a crosslinking agent is used to perform a low-degree primary crosslinking of protein materials such as bovine serum albumin, elastin-like protein, silk fibroin, soybean protein, and corn protein. Then, through wet spinning technology, a crosslinking agent is added to the coagulation bath to perform secondary crosslinking of the fibers in the coagulation bath. Finally, the fibers are post-stretched by stretching rollers and wound on collecting rollers to form toughened bio-protein fibers with certain stress and strain.

[0023] The key inventive point of this invention lies in the fact that it prepares a toughened bio-protein fiber by combining primary and secondary crosslinking with three toughening methods. The first toughening method involves directly adding the toughening agent to the coagulation bath. The second toughening method involves passing the fiber through a toughening agent solution during post-stretching. The third method is a combination of the aforementioned two methods. The working principle is as follows: the protein spinning solution undergoes a Schiff base chemical reaction with the glutaraldehyde crosslinking agent in the coagulation bath. Simultaneously, the toughening agent diffuses into the fiber interior, ensuring its distribution both inside and outside the fiber. After the primary and secondary crosslinking, the fiber strength is initially enhanced. Passing the fiber through a toughening agent bath during post-stretching further enhances its toughness without causing breakage.

[0024] In summary, this invention successfully prepared a bio-protein fiber with significantly improved toughness by performing low-degree primary crosslinking in the spinning solution and high-degree secondary crosslinking in the coagulation bath, while simultaneously enhancing the fiber's toughness (strain) by adding a non-toxic toughening agent (such as glycerol) to the coagulation bath or by passing the fiber through the toughening agent solution during post-stretching. This invention can significantly improve the mechanical properties of natural biomacromolecule fibers, enabling the preparation of high-strength and high-toughness biomacromolecule protein fibers, and providing high-performance materials for the application of natural biomacromolecule fibers in the biomedical field. Attached Figure Description

[0025] Figure 1 This is a top view schematic diagram of an apparatus for preparing toughened bio-protein fibers based on a secondary cross-linking system;

[0026] Figure 2 This is a schematic diagram of the post-stretching of fibers in this invention;

[0027] Figure 3 This is a schematic diagram of the post-stretching of fibers in this invention, with a toughening agent solution placed between the third and fourth stretching rollers.

[0028] Figure 4 This is a scanning electron microscope image of the fibers prepared in Example 1;

[0029] Figure 5 The stress / strain curve of the fiber prepared in Example 1 is shown below.

[0030] Figure 6 The stress / strain curve of the fiber prepared in Example 2 is shown below.

[0031] Figure 7 The stress / strain curve of the fiber prepared in Example 3 is shown below.

[0032] Figure 8 The stress / strain curve of the fiber prepared in Example 4 is shown below.

[0033] Figure 9 The stress / strain curve of the fiber prepared in Example 5 is shown below.

[0034] Figure 10 The stress / strain curve of the fiber prepared in Comparative Example 1 is shown.

[0035] Figure 11 The stress / strain curve of the fiber prepared in Comparative Example 2 is shown.

[0036] The meanings of the reference numerals in the attached figures are as follows:

[0037] 1-Injection pump; 2-Injector; 3-Connecting tube; 4-Plastic needle; 5-Multi-channel microfluidic / wet spinning chip; 6-Coagulation bath; 7-First stretching roller; 8-Sixth stretching roller; 9-Novary fiber; 10-Fiber guide; 11-Collection roller; 12-Toughening agent solution. Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0039] Example 1

[0040] 1) Preparation of primary crosslinking spinning solution

[0041] Weigh bovine serum albumin powder and dissolve it in purified water at pH 6.5. After shaking to dissolve, a protein solution with a concentration of 400 mg / mL is obtained.

[0042] The protein solution was placed on a magnetic stirrer and set to 700 rpm. Then, commercially available 50% glutaraldehyde was diluted to 10% and added dropwise (25 μL) to the protein solution at a volume ratio of 0.2% (0.2:100) to induce primary cross-linking of the protein. Finally, the primary cross-linked protein solution was centrifuged to remove bubbles, yielding the spinning solution.

[0043] 2) Preparation of coagulation bath

[0044] In a stainless steel water bath, 80% ethanol, 5% glutaraldehyde, 4% glycerol and 11% water were added in the same volume ratio, and the mixture was stirred thoroughly to obtain a homogeneous and stable coagulation bath solution.

[0045] 3) Fiber preparation

[0046] Combination Figure 1 , Figure 2 As shown, firstly, the spinning solution is loaded into syringe 2, and then syringe 2 is installed on injection pump 1, with the injection flow rate set to 100 μL / min. A ten-channel microfluidic / wet spinning chip 5 is selected. The speed of the stretching rollers is gradually increased within the range of 3 to 40 rpm to make the total stretching ratio 4 times (i.e., the ratio of the speed of the sixth stretching roller 8 to the speed of the first stretching roller 7), wherein the speed of the collecting roller 11 is equal to the speed of the sixth stretching roller 8.

[0047] Start the injection pump 1, and the spinning solution enters the ten-channel microfluidic / wet spinning chip 5 through the connecting tube 3, and then is squeezed into the coagulation bath 6 through the plastic seat needle 4; the nascent fiber 9 coming out of the coagulation bath 6 comes to the first stretching roller 7, and then the nascent fiber 9 is gradually stretched between each stretching roller. Under the action of the guide 10, it is finally collected on the collecting roller 11 to obtain secondary cross-linked toughened bio-protein fiber with a length of more than 3000m.

[0048] 4) Fiber determination

[0049] The stress and strain of the fiber were measured to be 149.3 MPa and 26.9%, respectively. The scanning electron microscope image of the fiber is shown below. Figure 4 As shown, the stress / strain curve is as follows: Figure 5 As shown. It should be understood that, Figures 5-11 The three curves in the image represent the same sample being tested three times.

[0050] Example 2

[0051] In this embodiment, a primary crosslinking spinning solution was prepared according to the method described in Example 1. 80% ethanol, 3% glutaraldehyde, 4% glycerol, and 13% water were added to a stainless steel water bath in the specified volume ratios, and the mixture was stirred thoroughly to obtain a homogeneous and stable coagulation bath solution.

[0052] Fiber preparation: according to Figure 1 The spinning solution is loaded into syringe 2, which is then attached to injection pump 1, and the injection flow rate is set to 100 μL / min. A ten-channel microfluidic / wet spinning chip 5 is selected, and the speed of the stretching rollers is gradually increased within the range of 3–40 rpm to achieve a total stretching ratio of 3.4 times (i.e., the ratio of the speeds of the sixth stretching roller 8 and the first stretching roller 7), wherein the speed of the collecting roller 11 is equal to the speed of the sixth stretching roller 8. Figure 2 The diagram shows the post-stretching process. The nascent fibers 9, after exiting the coagulation bath 6, are gradually stretched between the stretching rollers. Under the action of the guide 10, secondary cross-linked toughened bio-protein fibers with a length of more than 3000m are finally collected on the collecting roller 11.

[0053] Fiber Measurement: The stress and strain of the fiber were measured to be 122.6 MPa and 48.5%, respectively. The stress / strain curve of the fiber is shown below. Figure 6 As shown.

[0054] The difference between Example 2 and Example 1 is that the amount of glutaraldehyde and the total stretching ratio were reduced, resulting in lower stress and higher strain in the prepared fibers.

[0055] Example 3

[0056] In this embodiment, a primary crosslinking spinning solution was prepared according to the method described in Example 1. 80% ethanol, 2% glutaraldehyde, 4% glycerol, and 14% water were added to a stainless steel water bath in the specified volume ratios, and the mixture was stirred thoroughly to obtain a homogeneous and stable coagulation bath solution.

[0057] Fiber preparation: according to Figure 1 The spinning solution is loaded into syringe 2, which is then attached to injection pump 1, and the injection flow rate is set to 50 μL / min. A ten-channel microfluidic / wet spinning chip 5 is selected, and the speed of the stretching rollers is gradually increased within the range of 3–40 rpm to achieve a total stretching ratio of 2 (i.e., the ratio of the speeds of the sixth stretching roller 8 and the first stretching roller 7), wherein the speed of the collecting roller 11 is equal to the speed of the sixth stretching roller 8. Figure 2 The diagram shows the post-stretching process. The nascent fibers 9, after exiting the coagulation bath 6, are gradually stretched between the stretching rollers. Under the action of the guide 10, secondary cross-linked toughened bio-protein fibers with a length of more than 3000m are finally collected on the collecting roller 11.

[0058] Fiber Measurement: The stress and strain of the fiber were measured to be 90.7 MPa and 66.6%, respectively. The stress / strain curve of the fiber is shown below. Figure 7 As shown.

[0059] The difference between Example 3 and Example 2 is that the amount of glutaraldehyde and the total stretch ratio were further reduced, and the injection flow rate was also reduced. As a result, the stress of the prepared fiber was further reduced and the strain was further increased.

[0060] Example 4

[0061] In this embodiment, a primary crosslinking spinning solution was prepared according to the method described in Example 1. 80% ethanol, 3% glutaraldehyde, and 17% water were added to a stainless steel water bath in a specific volume ratio, and the mixture was stirred thoroughly to obtain a homogeneous and stable coagulation bath solution.

[0062] Fiber preparation: according to Figure 1 The spinning solution is loaded into syringe 2, which is then attached to injection pump 1, and the injection flow rate is set to 100 μL / min. A ten-channel microfluidic / wet spinning chip 5 is selected, and the speed of the stretching rollers is gradually increased within the range of 3–40 rpm to achieve a total stretching ratio of 3.4 times (i.e., the ratio of the speeds of the sixth stretching roller 8 and the first stretching roller 7), wherein the speed of the collecting roller 11 is equal to the speed of the sixth stretching roller 8. Figure 3 The diagram shows the post-stretching process. The nascent fibers 9, after exiting the coagulation bath 6, are gradually stretched between the stretching rollers. At the same time, the fibers pass through a toughening agent solution 12 containing 10% glycerol between the third and fourth stretching rollers. Finally, secondary cross-linked toughened bio-protein fibers with a length of more than 3000m are collected on the collecting roller 11.

[0063] Fiber Measurement: The stress and strain of the fiber were measured to be 121.5 MPa and 53.3%, respectively. The stress / strain curve of the fiber is shown below. Figure 8 As shown.

[0064] Example 4 shows that by passing the fiber through a toughening agent solution during the post-stretching process, the toughness of the prepared fiber is improved.

[0065] Example 5

[0066] In this embodiment, a primary crosslinking spinning solution was prepared according to the method described in Example 1. 80% ethanol, 3% glutaraldehyde, 5% glycerol, and 12% water were added to a stainless steel water bath in the specified volume ratios, and the mixture was stirred thoroughly to obtain a homogeneous and stable coagulation bath solution.

[0067] Fiber preparation: according to Figure 1 The spinning solution was loaded into syringe 2, which was then attached to injection pump 1, and the injection flow rate was set to 110 μL / min. A 20-channel microfluidic / wet spinning chip was selected, and the speed of the stretching rollers was gradually increased within the range of 3–40 rpm to achieve a total stretching ratio of 4 times (i.e., the ratio of the speeds of the sixth stretching roller 8 and the first stretching roller 7), wherein the speed of the collecting roller 11 was equal to the speed of the sixth stretching roller 8. Figure 3 The diagram shows the post-stretching process. The nascent fibers 9 emerging from the coagulation bath 6 are gradually stretched between the stretching rollers. At the same time, the fibers pass through a toughening agent solution 12 containing 10% glycerol between the third and fourth stretching rollers. Finally, secondary cross-linked toughened bio-protein fibers with a length of more than 3000m are collected on the collecting roller 11.

[0068] Fiber Measurement: The stress and strain of the fiber were measured to be 169.7 MPa and 33.4%, respectively. The stress / strain curve of the fiber is shown below. Figure 9 As shown.

[0069] The difference between Example 5 and Example 2 is that the number of channels, the amount of glycerin, and the total stretch ratio are increased. At the same time, toughening is performed during the post-stretching process, resulting in a further increase in fiber stress and a decrease in strain.

[0070] A comparison of the test data from the above five embodiments shows that by changing the concentration of the crosslinking agent (glutaraldehyde) or toughening agent (glycerol) in the coagulation bath, and by selecting the method of adding the toughening agent and setting various spinning process parameters, the present invention can regulate the mechanical properties and toughness of the obtained fibers, thereby achieving the goals of process optimization and fiber filament production.

[0071] Comparative Example 1

[0072] In this embodiment, a primary crosslinking spinning solution was prepared according to the method described in Example 1. 80% ethanol, 3% glutaraldehyde, and 17% water were added to a stainless steel water bath in a specific volume ratio, and the mixture was stirred thoroughly to obtain a homogeneous and stable coagulation bath solution.

[0073] In this embodiment, fibers are prepared according to the process parameters described in Example 2.

[0074] Fiber Measurements: The stress and strain of the fiber were measured at 126.0 MPa and 37.9%, respectively. The stress / strain curve of the fiber is shown below. Figure 10 As shown.

[0075] As can be seen from Example 2 and Comparative Example 1, the addition of 4% toughening agent glycerol in Example 2 compared to Comparative Example 1 increased the fiber strain from 37.9% to 48.5%, an increase of 10.6%. This demonstrates that the present invention prepares protein fibers with enhanced toughness through the use of a toughening agent in secondary crosslinking. Conversely, fibers obtained without the addition of a toughening agent in the coagulation bath exhibit lower toughness.

[0076] Comparative Example 2

[0077] In this embodiment, bovine serum albumin powder was weighed and dissolved in purified water at pH 6.5. After shaking and dissolving, a protein solution with a concentration of 400 mg / mL was obtained.

[0078] The prepared protein solution was used to prepare fibers according to the coagulation bath composition parameters and fiber preparation process parameters described in Example 2.

[0079] Fiber Measurements: The stress and strain of the fiber were measured to be 102.4 MPa and 49.8%, respectively. The stress / strain curve of the fiber is shown below. Figure 11 As shown.

[0080] As can be seen from Example 2 and Comparative Example 2, Example 2, compared to Comparative Example 2, added 0.2% (0.2:100) of primary crosslinking to the protein solution, resulting in an increase in fiber stress from 102.4 MPa to 122.6 MPa, an increase of 20.2 MPa. Therefore, this invention successfully prepared protein fibers with enhanced strength through a combination of primary and secondary crosslinking. Conversely, the resulting fibers would have lower strength if the primary and secondary crosslinking methods were not performed simultaneously.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. All simple and equivalent changes and modifications made in accordance with the claims and description of this application fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A method for preparing toughened bio-protein fibers based on a secondary cross-linking system, characterized in that, Includes the following steps: S1: A cross-linking agent is added dropwise to the protein solution to perform primary cross-linking, forming a protein spinning solution with a certain cross-linking network; wherein, the protein is one or more of bovine serum albumin, elastin-like protein, silk fibroin, soy protein, and corn protein; the concentration of the protein solution is 3~600 mg / mL; the primary cross-linking agent includes: glutaraldehyde, PEG dialdehyde, and genipin; the volume ratio of the cross-linking agent to the protein solution is (0.05~1):100; the concentration of the cross-linking agent component in the primary cross-linking agent solution is 5%~20%; S2: The protein spinning solution obtained in step S1 is extruded through an injection pump and fed into a coagulation bath containing a certain concentration of crosslinking agent via a multi-channel microfluidic / wet spinning chip, thereby undergoing secondary crosslinking; wherein, the coagulation bath is an aqueous solution containing a dehydrating agent and a crosslinking agent; the dehydrating agent is one or more of methanol, ethanol, and polyols; the crosslinking agent for secondary crosslinking includes: glutaraldehyde, PEG dialdehyde, and genipin; the concentration of the crosslinking agent component in the coagulation bath is 0.5%~10%; S3: After the fiber undergoes secondary cross-linking in the coagulation bath, it is post-stretched by a stretching roller and then wound up on a collecting roller to obtain toughened bio-protein fiber with certain stress and strain. The toughening process is carried out in the following three ways: a) adding a toughening agent to the coagulation bath in step S2, with a toughening agent concentration of 4-10%; b) passing the fiber through a toughening agent solution during the post-stretching process in step S3, with a toughening agent concentration of 0.5%-50%; c) a combination of the above two methods; the toughening agent is glycerol.

2. The method according to claim 1, characterized in that, In step S1, the crosslinking agent is added dropwise in a volume of 5~200μL.

3. The method according to claim 1, characterized in that, In step S2, the multi-channel microfluidic / wet spinning chip is a structural unit in which a central channel is connected to a stainless steel microtube or a glass conical microtube connecting tube, and multiple branch channels are evenly distributed in the same direction inside the chip. The number of the multiple branch channels is 2 to 100 channels.

4. The method according to claim 1, characterized in that, In step S2, the flow rate extruded by the injection pump is 0.5~500μL / min.

5. The method according to claim 1, characterized in that, In step S2, the concentration of the dehydrating agent in the coagulation bath is 50%~99.5%.

6. The method according to claim 1, characterized in that, In step S3, the rotational speed of the stretching roller is 1~100 rpm.

7. A toughened bio-protein fiber prepared by the method according to any one of claims 1 to 6.

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