A spinning process suitable for the formation of protein fibres

Abstract

The application provides a spinning preparation process suitable for protein fiber forming, which comprises the following steps: S1: dissolving protein in water and adding a trace amount of crosslinking agent to make the protein pre-react to obtain a protein spinning stock solution; S2: preparing a coagulation bath, wherein the volume fraction of the crosslinking agent is 1-10%; S3: feeding the protein spinning stock solution into a needle through an injection pump, making the protein spinning stock solution first pass through an air layer with a height of 1-10 mm, and then enter the coagulation bath containing the crosslinking agent under the traction of its own gravity, and chemical crosslinking reaction and dehydration occur to form fibers; and S4: performing differential stretching and collection to obtain a high-performance protein fiber after stretching treatment. According to the method, the continuity and stability of the protein fiber spinning are obviously improved, the efficiency of fiber forming is greatly improved, a material basis is laid for the application of the biological protein fiber in the fields of biological medicine and special equipment, and the method has a wide application prospect.

Description

Technical Field

[0001] This invention relates to a continuous and stable preparation process for biological protein fibers, specifically an optimized preparation process for high-performance protein fibers inspired by globular and random proteins. Background Technology

[0002] High-performance bio-protein fibers, such as spider silk and silkworm silk, which possess high mechanical strength, have attracted considerable research and attention. However, the limited production of natural spider silk and the relatively low mechanical properties of silkworm silk make it difficult for natural fibers to meet the needs of mass production or certain specific applications, thus restricting their further widespread use. Therefore, developing a bio-protein fiber that is readily available, possesses excellent mechanical properties, and can be mass-produced is one of the urgent challenges that needs to be addressed.

[0003] The abundance of globular and random proteins in nature, such as bovine serum albumin, ovalbumin, β-lactoglobulin, and elastin-like proteins, offers new prospects and opportunities for the preparation of novel fibers with strong mechanical properties. Unlike traditional fibrous proteins, most globular proteins contain two or more secondary structural units embedded within the protein and possess hydrophobic properties; while hydrophilic residues (-NH2, -COOH, etc.) are distributed on the protein surface, making it difficult for the proteins to assemble or stack tightly through intermolecular interactions. This results in a certain lag in the reaction during fiber formation due to incomplete exposure of functional groups, leading to numerous defects in the fibers and making it difficult to effectively and stably prepare high-performance biofibers. Especially for the currently mature wet spinning process, proteins that fail to react promptly after entering the coagulation bath will precipitate due to dehydration and gradually adhere to and stack between the tube wall and the needle over time, increasing the frequency of needle blockage and ultimately resulting in poor continuity and stability of the wet spinning process. Therefore, it is urgent to develop and optimize more efficient preparation processes to achieve continuous and stable production of high-performance biofibers for constructing globular proteins. Summary of the Invention

[0004] The purpose of this invention is to provide a spinning process suitable for protein fiber forming, thereby solving the problem that existing wet spinning processes for spherical protein bio-fibers are difficult to achieve continuous stability.

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

[0006] A spinning preparation process suitable for protein fiber forming is provided, comprising the following steps: S1: At room temperature, protein is dissolved in a certain volume of water, and then a trace amount of crosslinking agent is added to the solution to allow the protein to undergo a pre-reaction, thereby obtaining a protein spinning solution. The concentration of the trace amount of crosslinking agent in the protein spinning solution is 1-10 wt‰; S2: A coagulation bath is prepared, wherein the coagulation bath is a mixed solution of dehydrating agent, crosslinking agent, and water, and the volume fraction of the crosslinking agent in the coagulation bath is 1-10%; S3: The protein spinning solution is fed into a needle by an injection pump, and the flow rate of the injection pump is set to 100-120 μL / min, so that the protein spinning solution first passes through an air layer with a height of 1-10 mm, and then is drawn into the coagulation bath containing the crosslinking agent by its own gravity. The solution is dehydrated and forms fibers through a chemical crosslinking reaction with the crosslinking agent, and is collected by a collecting roller; S4: The solution is collected by differential stretching using collecting rollers of the same diameter but different rotation speeds to obtain a high-performance protein fiber that has undergone post-stretching treatment.

[0007] Preferably, in step S1, the protein includes a fusion structural protein and a natural protein, and the concentration of the protein in the protein spinning solution is 200-600 mg / mL.

[0008] Preferably, in step S1, the concentration of the trace crosslinking agent in the protein spinning solution is 1–10 wt‰, more preferably 5–10 wt‰. According to research based on the present invention, the addition of the trace crosslinking agent can pre-react the protein in the spinning solution, reducing structural defects that occur during fiber forming and further improving the overall performance of the fiber.

[0009] Preferably, in step S1, the trace crosslinking agent is glutaraldehyde, PEG dialdehyde, or Danipridine.

[0010] Preferably, in step S2, the concentration of the crosslinking agent in the coagulation bath is 1-10% (v / v), more preferably 5-10% (v / v). Research according to the present invention has found that the amount of crosslinking agent used in this step is very important. If the concentration of the crosslinking agent is too low (below 1%), fiber forming is difficult, while if it is too high (above 10%), it easily leads to increased fiber brittleness.

[0011] Preferably, in step S2, the dehydrating agent is one of methanol, ethanol, and isopropanol, and the crosslinking agent is glutaraldehyde, PEG dialdehyde, or Daniper, etc.

[0012] Preferably, in step S3, the height of the air layer is 1 to 10 mm, more preferably 5 to 10 mm.

[0013] Preferably, in step S3, the flow rate of the injection pump is 100-120 μL / min, more preferably 110-120 μL / min.

[0014] Preferably, step S4 includes: differential stretching collection by a first collecting roller, a second collecting roller, and a third collecting roller with the same diameter but different rotation speeds, wherein the angular velocities of the first collecting roller, the second collecting roller, and the third collecting roller are ω1, ω2, and ω3, respectively, and the nascent fiber is stretched by ω3 / ω1 times to obtain a high-performance protein fiber after post-stretching treatment.

[0015] Dry-wet spinning, also known as dry-jet wet spinning, is a process commonly used for high-molecular polymers such as carbon fibers and polyacrylonitrile, but rarely combined with the spinning of biological protein macromolecules. Because the functional groups available for cross-linking reactions in globular proteins are not fully exposed, the time for the protein to enter the coagulation bath and form nascent fibers is relatively long. Therefore, during wet spinning, the protein solution enters the coagulation bath, dehydrates and precipitates, adhering to the tube wall and between the needle, increasing the frequency of needle blockage and resulting in poor continuity and stability of the wet spinning process.

[0016] The main advantages of this invention in preparing protein fibers using a dry-wet spinning process are as follows: First, after the spinning solution is extruded by a micro-pump, it passes through an air layer, where it forms a jet and is stretched. Second, while increasing the spinning speed (ten times or more than that of wet spinning), it effectively prevents the protein solution from dehydrating and settling against the wall of the dispensing needle in the coagulation bath, thus preventing adhesion. Third, this invention also adds a trace amount of crosslinking agent when preparing the spinning solution to pre-react the protein, further shortening the fiber forming time of globular proteins in the coagulation bath and greatly improving the overall spinning efficiency and continuity. Fourth, dry-wet spinning can use spinning solutions with higher concentrations and viscosities (up to 200-600 mg / mL), providing more favorable conditions for spinning processes of more large-molecule biological proteins.

[0017] The spinning process for protein fiber forming provided by the present invention has the following advantages compared with the prior art:

[0018] 1) By adopting a dry-wet spinning process, the problem of poor continuity and stability of a large number of globular and random proteins during the spinning process in the prior art is solved. The method of the present invention can be applied to the preparation of fused structure protein fibers, including globular and random proteins, as well as natural protein fibers.

[0019] 2) By pre-adding a small amount of crosslinking agent to the spinning solution to facilitate better chemical crosslinking, continuous and stable preparation of bio-protein fibers was achieved, and the mechanical properties of the fibers were enhanced to a certain extent.

[0020] 3) Increasing the spinning speed improved production efficiency;

[0021] 4) A post-stretched fiber with excellent mechanical properties was prepared by combining the post-stretching process.

[0022] In summary, the spinning process for protein fiber forming provided by this invention significantly improves the continuity and stability of protein fiber spinning, greatly enhances the efficiency of fiber forming, and produces protein fibers with excellent mechanical properties. This lays a material foundation for the application of bio-protein fibers in fields such as surgical sutures, biomedicine, and special equipment, and has broad application prospects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating a spinning process for protein fiber forming according to the present invention. Detailed Implementation

[0024] 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. Unless otherwise specified, the techniques used in the embodiments are conventional practices in the art, or experimental methods recommended by the reagent kit and instrument manufacturers. Unless otherwise specified, the reagents and materials used in the embodiments are commercially available.

[0025] Example 1: A spinning preparation process and post-stretching treatment suitable for bovine serum albumin fiber forming

[0026] (1) At room temperature, bovine serum albumin was dissolved in a certain volume of water to obtain bovine serum albumin spinning solution with a concentration of 500 mg / mL. Then, a trace amount of glutaraldehyde was added to react with it in advance, and a mixed solution of ethanol, water and glutaraldehyde with a volume fraction ratio of 16:3:1 was used as the coagulation bath.

[0027] (2) As attached Figure 1 As shown, the spinning solution is fed into a dispensing needle with an inner diameter of 210 μm via an injection pump. The injection pump flow rate is set to 100–120 μL / min. It first passes through an air layer of approximately 10 mm in height, and then is introduced into the mixed coagulation bath containing glutaraldehyde in step (1) (e.g., ...). Figure 1 As shown), glutaraldehyde undergoes a chemical cross-linking reaction with bovine serum albumin, followed by dehydration to form fibers, which are collected by collecting roller I (where collecting roller I rotates at 7 rpm).

[0028] (3) The nascent fibers collected in step (2) are subjected to differential stretching treatment by collecting rollers I to III with the same diameter but different rotation speeds. The angular velocities of collecting roller I and collecting roller III are ω1 to ω3 respectively. The ratio of ω3:ω2:ω1 is set to 4:3:2 respectively to obtain fibers stretched twice.

[0029] (4) The continuous fiber collection time is about 3 to 5 hours and the collection length is about 600 to 1000 m.

[0030] Comparative Example 1: Preparation of bovine serum albumin fibers by wet spinning process

[0031] (1) At room temperature, bovine serum albumin was dissolved in a certain volume of water to obtain bovine serum albumin spinning solution with a concentration of 500 mg / mL. Then, a trace amount of glutaraldehyde was added to react with it in advance, and a mixed solution of ethanol, glutaraldehyde and water in a volume fraction ratio of 16:3:1 was used as the coagulation bath.

[0032] (2) As attached Figure 1 As shown, the spinning solution is fed into a dispensing needle with an inner diameter of 210 μm through an injection pump (where the flow rate of the injection pump is set to 10 μL / min), and then directly into the mixed coagulation bath containing glutaraldehyde in step (1). After the glutaraldehyde undergoes a chemical cross-linking reaction with bovine serum albumin, it is dehydrated to form fibers, which are collected by collecting roller I (where the rotation speed of collecting roller I is 3 rpm).

[0033] (3) The nascent fibers collected in step (2) are subjected to differential stretching treatment by collecting rollers I to III with the same diameter but different rotation speeds. The angular velocities of collecting roller I and collecting roller III are ω1 to ω3, respectively, and ω3:ω2:ω1 = 4:3:2 are set respectively, so that 2 times the stretching fiber is obtained.

[0034] (4) The continuous fiber collection time is about 1.5 to 3 hours, and the collection length is about 130m to 260m.

[0035] Comparative Example 2: Preparation of bovine serum albumin fibers by wet spinning process

[0036] (1) At room temperature, bovine serum albumin was dissolved in a certain volume of water to obtain a bovine serum albumin spinning solution with a concentration of 500 mg / mL, and a coagulation bath was used with a mixed solution of ethanol, glutaraldehyde and water in a volume ratio of 16:3:1.

[0037] (2) As attached Figure 1 As shown, the spinning solution is fed into a dispensing needle with an inner diameter of 210 μm through an injection pump (where the flow rate of the injection pump is set to 10 μL / min), and then directly into the mixed coagulation bath containing glutaraldehyde in step (1). After the glutaraldehyde undergoes a chemical cross-linking reaction with bovine serum albumin, it is dehydrated to form fibers, which are collected by collecting roller I (where the rotation speed of collecting roller I is 3 rpm).

[0038] (3) The nascent fibers collected in step (2) are subjected to differential stretching treatment by collecting rollers I to III with the same diameter but different rotation speeds. The angular velocities of collecting roller I and collecting roller III are ω1 to ω3, respectively, and ω3:ω2:ω1 = 4:3:2 are set respectively, so that 2 times the stretching fiber is obtained.

[0039] (4) The continuous fiber collection time is about 1 to 2 hours, and the collection length is about 87m to 170m.

[0040] Comparison of Comparative Examples 1 and 2 revealed that when the spinning solution was pretreated with trace amounts of glutaraldehyde, the spinning process time and stability were significantly improved.

[0041] By comparing Example 1 with Comparative Examples 1 and 2, it was found that the flow rate of the injection pump (120 μL / min) in Example 1 using the dry-wet spinning method was much higher than that in Comparative Examples 1 and 2 (10 μL / min). This means that the spinning efficiency of the dry-wet spinning process used in the invention has been greatly improved. In addition, when the pre-treated spinning solution passes through a 10 mm high air layer after being extruded through the dispensing needle instead of directly entering the coagulation bath, the spinning preparation time is extended by a greater margin, and the fiber collection length is also significantly improved.

[0042] 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 spinning process suitable for protein fiber forming, characterized in that, Includes the following steps: S1: At room temperature, the protein is dissolved in a certain volume of water, and then a trace amount of cross-linking agent is added to it to cause the protein to undergo a pre-reaction, thereby obtaining a protein spinning solution. The concentration of the trace cross-linking agent in the protein spinning solution is 5~10wt‰, the protein is bovine serum albumin, the concentration of the protein in the protein spinning solution is 200~600 mg / mL, and the trace cross-linking agent is one of glutaraldehyde, PEG dialdehyde, and Danipin. S2: Prepare a coagulation bath, wherein the coagulation bath is a mixed solution of a dehydrating agent, a crosslinking agent, and water, wherein the volume fraction of the crosslinking agent in the coagulation bath is 1-10%, the dehydrating agent is one of methanol, ethanol, and isopropanol, and the crosslinking agent is one of glutaraldehyde, PEG dialdehyde, and Danipin. S3: The protein spinning solution is fed into the needle by an injection pump. The flow rate of the injection pump is set to 100~120μL / min. The protein spinning solution first passes through an air layer with a height of 1~10mm, and then is drawn into a coagulation bath containing a crosslinking agent by its own gravity. It is dehydrated and forms fibers through a chemical crosslinking reaction with the crosslinking agent, and is collected by a collecting roller. S4: Differential stretching and collection is performed by a first collecting roller, a second collecting roller, and a third collecting roller with the same diameter but different rotation speeds. The angular velocities of the first collecting roller, the second collecting roller, and the third collecting roller are ω1, ω2, and ω3, respectively. The nascent fiber is stretched by ω3 / ω1 times to obtain a high-performance protein fiber that has undergone post-stretching treatment.

2. The spinning preparation process according to claim 1, characterized in that, In step S2, the volume fraction of the crosslinking agent in the coagulation bath is 5-10%.

3. The spinning preparation process according to claim 1, characterized in that, In step S3, the height of the air layer is 5~10mm.

4. The spinning preparation process according to claim 1, characterized in that, In step S3, the flow rate of the injection pump is 110~120μL / min.

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