A rare earth ion-enhanced silk fibroin fiber and its preparation method

Abstract

The present invention discloses a rare earth ion-enhanced silk fibroin fiber and a preparation method thereof, comprising the following steps: S1: degumming silk in an alkaline salt solution to obtain degummed silk; S2: preparing a dissolution solution containing rare earth ions, calcium ions and an organic solvent, and dissolving the degummed silk in the dissolution solution to obtain a spinning solution with a certain concentration; S3: extruding or sucking the spinning solution into a multi-channel spinning chip; S4: after the spinning solution is extruded through the chip, entering a coagulation bath to form multiple strands of fiber fibrils; S5: after the multiple strands of fiber fibrils come out of the coagulation bath, performing differential stretching treatment through a stretching roller, and finally obtaining a rare earth ion-enhanced silk fibroin fiber on a collecting roller. The rare earth ion-enhanced silk fibroin fiber prepared according to the present invention has excellent mechanical properties, excellent biocompatibility and degradability, and has broad application prospects in the medical field.

Description

Technical Field

[0001] The present invention relates to the technical field of bio-protein fiber preparation, and particularly relates to a rare earth ion-enhanced silk fibroin fiber and a preparation method thereof. Background Art

[0002] Silk is a kind of protein fiber formed by silkworms spinning silk, which has excellent biocompatibility, degradability and other advantages, and is widely used in the fields of biomedicine, industry and agriculture, such as surgical sutures, artificial ligaments, silk quilts, silk clothing and other aspects. Silk can be mass-produced by artificial breeding methods. However, as a surgical suture, its degradation rate is far slower than that of regenerated silk, which undoubtedly limits its use in biomedicine; on the other hand, some waste silk will also be generated during the weaving process and the discarded and recycled waste silk clothes. If these waste silk are directly discarded, it will undoubtedly cause waste of resources and environmental hazards. Therefore, how to optimize the rapid degradability of silk and the recycling of waste silk has become a key scientific and technological problem that needs to be researched and solved at present. Summary of the Invention

[0003] The purpose of the present invention is to provide a rare earth ion-enhanced silk fibroin fiber and a preparation method thereof, so as to solve the problem that the silk in the prior art cannot simultaneously meet the requirements of rapid degradation and waste silk recycling.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] According to the first aspect of the present invention, a preparation method of a rare earth metal ion-enhanced silk fibroin fiber is provided, including the following steps: S1: degumming silk in an alkaline salt solution to remove sericin protein and obtain pure fibroin fiber; S2: prepare a dissolution solution containing rare earth metal ions, calcium ions and an organic solvent, and dissolve the degummed silk in the dissolution solution to obtain a spinning solution with a certain concentration; the organic solvent is one or more of formic acid, hexafluoroisopropanol, and trifluoroacetic acid; the source of the rare earth metal ions is a chloride of the rare earth metal ions, and the concentration of the chloride of the rare earth metal ions is 1.0-6.0%, and the source of the calcium ions is calcium chloride, and the concentration of the calcium chloride is 1-10%; S3: use a metering device to extrude or suck the spinning solution into a multi-channel spinning chip to ensure uniform distribution of the spinning solution; S4: after the spinning solution is extruded through the chip, it enters a coagulation bath containing a certain concentration of coagulant and toughening agent to form multiple fiber fibrils; S5: after the multiple fiber fibrils come out of the coagulation bath, they are subjected to differential stretching treatment through a stretching roller, and finally a rare earth metal ion-enhanced silk fibroin fiber is obtained on a collecting roller.

[0006] Preferably, in step S1, the silk raw material is natural silk or waste silk obtained after removing pupae from natural cocoons, and the natural cocoons are one or two of mulberry cocoons and tussah cocoons. Most preferably, they are mulberry cocoons.

[0007] Preferably, in step S1, the solute of the alkaline salt solution is one or more of sodium carbonate and sodium bicarbonate, and the concentration of the alkaline salt solution is 0.01% - 1.00%. Most preferably, it is 0.05%.

[0008] In step S2, the rare earth metal ions include lanthanide elements (lanthanum, cerium, praseodymium, neodymium, etc.) as well as scandium and yttrium, a total of 16 elements (excluding the radioactive element promethium). It should be understood that according to the method provided by the present invention, the rare earth metal ions are any one of these 16 rare earth elements.

[0009] Preferably, in step S2, the source of the rare earth metal ions is chloride with crystal water or chloride without crystal water.

[0010] Preferably, in step S2, the dissolution state of the rare earth metal ions is completely dissolved or not completely dissolved.

[0011] Preferably, in step S2, the concentration of the rare earth metal ion chloride in the dissolution solution used is 1.0 - 3.0%, and the concentration of calcium chloride is 3.0 - 5.0%.

[0012] Preferably, in step S2, the dissolution solution used contains lanthanum chloride with a mass fraction of 1.0%, calcium chloride with a mass fraction of 5%, and the organic solvent is formic acid.

[0013] Preferably, in step S4, by volume, the coagulation bath contains 50 - 60% ethanol and 2 - 5% glycerol. More preferably, by volume, the coagulation bath contains 50 - 60% isopropanol and 2 - 5% glycerol.

[0014] Preferably, in step S5, the drawing ratio of the differential drawing is 4 - 10.

[0015] Preferably, the degumming lasts for a period of 10 - 120 min, most preferably 30 min.

[0016] Preferably, in step S2, the degummed silk fibroin fiber is the dried degummed silk after natural drying; the degumming rate of the degummed silk fibroin fiber is 20% - 35%, more preferably 25% - 30%.

[0017] Preferably, the source of the rare earth metal ions includes chloride with crystal water and chloride without crystal water, more preferably anhydrous chloride; the dissolution process is divided into two ways: completely dissolved and not completely dissolved, and preferably it is not completely dissolved.

[0018] Preferably, in step S3, the metering device is a micro-injection pump, a plunger pump, a metering pump or the like, and most preferably a plunger pump; the multi-channel spinning chip is a microfluidic device containing a main channel and a plurality of branch channels; the material of the chip is stainless steel or aluminum alloy resistant to organic dissolution.

[0019] Preferably, in step S4, the coagulant of the coagulation bath is an alcohol such as ethanol, methanol, isopropanol, etc.; the concentration of the coagulant is 10%-90%, more preferably 50%-60%; the toughening agent of the coagulation bath is one or more of glycerol, ethyl acetate, ectoine, dioctyl phthalate, and most preferably glycerol; the concentration of the toughening agent is 1%-10%, more preferably 2%-5%.

[0020] According to the present invention, in steps S4 and S5, the spinning solution is extruded into the coagulation bath through a microfluidic device containing a main channel and a plurality of branch channels to obtain a regenerated silk fibroin multifilament fibril. The number of single filaments in the multifilament is determined by the number of branch channels of the microfluidic device. The number of single filaments is equal to the number of branch channels. After solvent exchange in the coagulation bath, the multifilament fibril is coagulated into a primary fiber with a certain solid morphology. The primary fiber is differentially stretched between differential stretching rollers, and at the same time, the solvent volatilizes during the stretching process. Finally, a regenerated silk fibroin multifilament long fiber with certain mechanical properties is collected on the collecting roller.

[0021] According to a preferred embodiment of the present invention, a dissolution solution is prepared according to the ratio of 1% by mass fraction of cerium chloride and 5% by mass fraction of calcium chloride in the solvent; a coagulation bath with an isopropanol concentration of 60% and a glycerol concentration of 2% is prepared by volume ratio; after being fully stretched between differential stretching rollers with a total stretching ratio of 6.5 times, rare earth metal ion-enhanced silk fibroin fibers are collected on the collecting roller, and mechanical property tests are carried out. The stress is as high as 720.2±4.3 MPa, and the strain is 14.4±3.5%.

[0022] According to a most preferred embodiment of the present invention, a dissolution solution is prepared according to the ratio of 1% by mass fraction of lanthanum chloride and 5% by mass fraction of calcium chloride in the solvent, and a coagulation bath with an ethanol concentration of 50% and a glycerol concentration of 5% is prepared by volume ratio. After being fully stretched between differential stretching rollers with a total stretching ratio of 6.5 times, rare earth metal ion-enhanced silk fibroin fibers are collected on the collecting roller, and mechanical property tests are carried out. The stress is as high as 748.4±18.5 MPa, and the strain is 25.9±4.7%.

[0023] According to the second aspect of the present invention, there is provided a rare earth metal ion-enhanced silk fibroin fiber prepared by the above method.

[0024] Preferably, the rare earth metal ion - enhanced silk fibroin fiber is composed of multiple regenerated silk fibroin fiber filaments; the number of strands of the multiple fiber fibrils is 2 - 500, more preferably 5 - 50; the long fiber is a regenerated silk fibroin fiber with a length greater than 1000 m.

[0025] Preferably, for the rare earth metal ion - enhanced silk fibroin fiber prepared by the method of the present invention, the stress of the mechanical property is 50 - 1000 MPa, more preferably 100 - 800 MPa, and the strain is 5% - 100%, more preferably 10% - 80%.

[0026] It should be understood that, except for fibers directly derived from animals and plants, the methods for artificially preparing fibers can generally be divided into melt spinning, dry spinning, and wet spinning. Since protein fibers such as silk are not heat - resistant, wet spinning is undoubtedly the best choice for preparing regenerated silk. The team of Zhang Yingying at Tsinghua University reported a method of feeding rare earth ions to silkworms to prepare silk fibers with significantly improved strength and toughness. Since this method involves feeding rare earth ions to silkworms and synthesizing silk through the silkworm organism, there is currently no evidence indicating whether most of the rare earth ions enter the silk or other parts of the silkworm's body. Assuming that the silk contains rare earth ions, obviously the content of rare earth ions in the silk is also uncontrollable. Moreover, simply relying on silkworms to spin silk for silk production obviously has the defects of low yield and low efficiency, and it is also impossible to achieve continuous preparation of silk. Therefore, this method has the disadvantages of low synthesis efficiency, poor controllability, and inability to be continuously prepared.

[0027] However, in the present invention, by dissolving silk in a solution containing rare earth metal ions, calcium ions, and organic solvents, and then extruding the spinning solution into a coagulation bath, after the fiber exits the coagulation bath, orientation setting through post - stretching can obtain regenerated silk fibers with certain mechanical properties. By optimizing process parameters such as the spinning solution and coagulation bath and doping rare earth metal ions and other steps, regenerated silk fibroin fibers comparable to natural silk can be obtained, which has a positive significance for resource recycling and environmental protection while optimizing the degradation performance.

[0028] The key inventive points of the present invention mainly lie in that silk is dissolved by using organic solvents such as formic acid, while adding calcium ions as a dissolution promoter, and especially adding a certain content of rare earth metal ions as a structure enhancer to dissolve the silk well, obtaining a spinning solution with a certain viscosity. Then, the spinning solution is extruded into a coagulation bath through a microfluidic device containing a main channel and multiple branch channels to obtain a regenerated silk fibroin multifilament fibril. The multifilament fibril is coagulated into a primary fiber with a certain solid morphology after solvent exchange in the coagulation bath. The primary fiber is differentially stretched between differential stretching rollers, and at the same time, the solvent volatilizes during the stretching process. Finally, a regenerated silk fibroin multifilament long fiber with certain mechanical properties is collected on a collecting roller. When there is enough spinning solution, the fiber can be continuously stretched for more than 24 hours, achieving the purpose of continuous mass production.

[0029] The rare earth metal ion-reinforced silk protein fiber prepared according to the method of the present invention has excellent mechanical properties. Due to its excellent biocompatibility and biodegradability, it has broad application prospects in the medical field. Especially as an absorbable surgical suture, it can be gradually absorbed by the human body after wound healing without the need for a second operation to remove it, thus reducing the pain and medical costs of patients. In addition to surgical sutures, the regenerated silk fibroin fiber can also be used to prepare other biomaterials, such as tissue engineering scaffolds, drug carriers, etc., providing more innovative options for the biomedical field. With the in-depth research on regenerated silk fibroin fibers, it is expected to develop more fiber materials with special properties and application values in the future. Since the regenerated silk fibroin fiber has broad application prospects in multiple fields, its market potential is huge.

[0030] In summary, the present invention can dissolve and spin silk by a one-step method through using organic solvents such as formic acid, combining the dissolution-promoting and coordination-enhancing effects of calcium ions, and the structure-enhancing effect of rare earth metal ions, and winding to obtain regenerated silk fibroin fibers. The process is simple and convenient, and the mechanical properties of the obtained regenerated silk fibroin fibers are close to those of natural silk, providing a new technical method for the reuse of waste silk. The prepared regenerated silk fibroin fibers have both excellent mechanical properties and good biodegradability, and can be further applied to the biomedical field. Brief Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the experimental device, where 1 - spinning solution inlet; 2 - multi-channel chip; 3 - coagulation bath; 4 - first stretching roller; 5 - second stretching roller; 6 - collecting roller;

[0032] Figure 2 It is the stress-strain curve graph of the fiber in Example 1 of the present invention;

[0033] Figure 3It is the fiber stress-strain curve diagram of Example 2 in the present invention;

[0034] Figure 4 It is the fiber stress-strain curve diagram of Example 3 in the present invention;

[0035] Figure 5 It is the fiber stress-strain curve diagram of Example 4 in the present invention;

[0036] Figure 6 It is the fiber stress-strain curve diagram of Example 5 in the present invention;

[0037] Figure 7 It is the fiber stress-strain curve diagram of Example 6 in the present invention. Detailed implementation manners

[0038] The following further illustrates the present invention in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0039] Example 1

[0040] 1) Degumming of silk

[0041] Cut the silk without pupae and cut it into pieces. Put the silk into a 0.05% sodium carbonate solution, and after boiling and degumming, rinse the silk with purified water flowing water and then dry it. After drying, weigh the mass of the degummed silk, and calculate that the degumming rate is 26.9%.

[0042] 2) Preparation of spinning solution

[0043] Prepare a dissolution solution according to the proportion that the mass fraction of lanthanum chloride in the solvent is 0.5% and the mass fraction of calcium chloride is 5%. After stirring fully for half an hour, an undissolved suspension is obtained. Add the degummed silk to the suspension, and after fully dissolving, a spinning solution with a concentration of 13% is obtained.

[0044] 3) Preparation of coagulation bath

[0045] Prepare a coagulation bath with an ethanol concentration of 50% and a glycerol concentration of 5% by volume ratio.

[0046] 4) Spinning

[0047] As Figure 1 shown, use a 10-channel multi-channel chip 2, with a plunger pump as the power source, suck the spinning from the spinning solution inlet 1 into the chip. After passing through the fine needles at the rear section of the chip, the spinning solution is extruded into the coagulation bath 3 to form primary fibers. After the solvent exchange of multiple primary fibers in the coagulation bath, they are drawn to the first stretching roller 4, passed through the second stretching roller 5, and are fully stretched between the differential stretching rollers with a total stretching multiple of 6.5 times, and a regenerated silk fibroin multifilament long fiber with a certain stress strain is obtained on the collecting roller.

[0048] 5) Test characterization

[0049] The mechanical properties of the obtained regenerated silk fibroin multifilament long fibers were tested, and the results are as Figure 2 shown. Each line of different colors represents a different sample, where the stress is 687.1 ± 4.5 MPa and the strain is 18.9 ± 1.9%.

[0050] Example 2

[0051] 1) Degumming of silk

[0052] The pupa-removed silk was cut into pieces and placed in a 0.05% sodium carbonate solution. After boiling, the degummed silk was rinsed with purified water flowing continuously and then dried. After drying, the mass of the degummed silk was weighed, and the degumming rate was calculated to be 25.7%.

[0053] 2) Preparation of spinning solution

[0054] A dissolving solution was prepared according to the proportion of 1% lanthanum chloride and 5% calcium chloride in the solvent. After stirring thoroughly for half an hour, an undissolved suspension was obtained. The degummed silk was added to the suspension, and after complete dissolution, a spinning solution with a concentration of 13% was obtained.

[0055] 3) Preparation of coagulation bath

[0056] A coagulation bath with an ethanol concentration of 50% and a glycerol concentration of 5% was prepared according to the volume ratio.

[0057] 4) Spinning

[0058] Using a 10-channel aluminum alloy chip and a plunger pump as the power source, the spinning solution was sucked into the chip. After passing through the fine needle at the rear section of the chip, the spinning solution was extruded into the coagulation bath to form primary fibers. After solvent exchange in the coagulation bath, multiple primary fibers were drawn onto the first stretching roller. After being fully stretched between the differential stretching rollers with a total stretching multiple of 6.5 times, regenerated silk fibroin multifilament long fibers with certain stress and strain were obtained on the collecting roller.

[0059] 5) Test characterization

[0060] The mechanical properties of the obtained regenerated silk fibroin multifilament long fibers were tested, and the results are as Figure 3 shown. Each line of different colors represents a different sample, where the stress is 748.4 ± 18.5 MPa and the strain is 25.9 ± 4.7%.

[0061] Example 3

[0062] 1) Degumming of silk

[0063] Cut the pupa-removed silk into pieces, put the silk into a 0.05% sodium carbonate solution, and after boiling and degumming, rinse the silk with purified water flowing water and then dry it. After drying, weigh the mass of the degummed silk, and calculate that the degumming rate is 26.3%.

[0064] 2) Preparation of spinning solution

[0065] Prepare a dissolution solution according to the ratio of 2% mass fraction of lanthanum chloride and 5% mass fraction of calcium chloride in the solvent. After stirring thoroughly for half an hour, an undissolved suspension is obtained. Add the degummed silk to the suspension and fully dissolve it to obtain a spinning solution with a concentration of 13%.

[0066] 3) Preparation of coagulation bath

[0067] Prepare a coagulation bath with an ethanol concentration of 50% and a glycerol concentration of 5% by volume ratio.

[0068] 4) Spinning

[0069] Use a 10-channel aluminum alloy chip, with a plunger pump as the power source, suck the spinning solution into the chip, and after passing through the fine needle at the rear section of the chip, the spinning solution is extruded into the coagulation bath to form primary fibers. After solvent exchange of multiple primary fibers in the coagulation bath, they are drawn to the first stretching roller, and after being fully stretched between the differential stretching rollers with a total stretching multiple of 6.5 times, regenerated silk fibroin multifilament long fibers with a certain stress-strain are obtained on the collecting roller.

[0070] 5) Testing and characterization

[0071] Perform mechanical property tests on the obtained regenerated silk fibroin multifilament long fibers, and the results are as Figure 4 shown. Each line of different colors represents a different sample, where the stress is 640.8 ± 9.4 MPa and the strain is 17.7 ± 0.8%.

[0072] Example 4

[0073] 1) Silk degumming

[0074] Cut the pupa-removed silk into pieces, put the silk into a 0.05% sodium carbonate solution, and after boiling and degumming, rinse the silk with purified water flowing water and then dry it. After drying, weigh the mass of the degummed silk, and calculate that the degumming rate is 27.5%.

[0075] 2) Preparation of spinning solution

[0076] Prepare a dissolution solution according to the ratio of 1% mass fraction of lanthanum chloride and 5% mass fraction of calcium chloride in the solvent. After stirring thoroughly, a completely dissolved dissolution solution is obtained. Add the degummed silk to the clear and transparent dissolution solution and fully dissolve it to obtain a spinning solution with a concentration of 13%.

[0077] 3) Preparation of coagulation bath

[0078] Prepare a coagulation bath with an ethanol concentration of 50% and a glycerol concentration of 5% by volume ratio.

[0079] 4) Spinning

[0080] Use a 10-channel aluminum alloy chip, with a plunger pump as the power source, suck the spinning solution into the chip. After passing through the fine needles at the rear section of the chip, the spinning solution is extruded into the coagulation bath to form nascent fibers. After solvent exchange in the coagulation bath, multiple nascent fibers are drawn to the first stretching roller, and are fully stretched between differential stretching rollers with a total stretching multiple of 6 times, and regenerated silk fibroin multifilament long fibers with a certain stress-strain are obtained on the collecting roller.

[0081] 5) Testing and characterization

[0082] Conduct mechanical property tests on the obtained regenerated silk fibroin multifilament long fibers. The results are as Figure 5 shown. Each line of different colors represents a different sample, where the stress is 576.6 ± 18.6 MPa and the strain is 24.3 ± 5.6%.

[0083] Example 5

[0084] 1) Degumming of silk

[0085] Cut the silk after removing the pupa into pieces, put the silk into a 0.05% sodium carbonate solution, boil it, and rinse the degummed silk with purified water flowing water and then dry it. After drying, weigh the mass of the degummed silk, and calculate that the degumming rate is 26.6%.

[0086] 2) Preparation of spinning solution

[0087] Prepare a dissolution solution according to the proportion of 1% cerium chloride mass fraction and 5% calcium chloride mass fraction in the solvent, stir for half an hour to obtain an undissolved suspension. Add the degummed silk to the suspension, and fully dissolve it to obtain a spinning solution with a concentration of 15%.

[0088] 3) Preparation of coagulation bath

[0089] Prepare a coagulation bath with an isopropanol concentration of 60% and a glycerol concentration of 2% by volume ratio.

[0090] 4) Spinning

[0091] Use a 10-channel aluminum alloy chip, with a micro-injection pump as the power source, squeeze the spinning solution into the chip. After passing through the fine needles at the rear section of the chip, the spinning solution is extruded into the coagulation bath to form nascent fibers. After solvent exchange in the coagulation bath, multiple nascent fibers are drawn to the first stretching roller, and are fully stretched between differential stretching rollers with a total stretching multiple of 6.5 times, and regenerated silk fibroin multifilament long fibers with a certain stress-strain are obtained on the collecting roller.

[0092] 5) Test characterization

[0093] The mechanical properties of the obtained regenerated silk fibroin multifilament were tested, and the results were as follows: Figure 6 As shown, each line of different colors represents a different sample, where the stress is 720.2±4.3MPa and the strain is 14.4±3.5%.

[0094] Example 6

[0095] 1) Silk degumming

[0096] The silk was cut into pieces after the pupae were removed, and the silk was placed in a 0.05% sodium carbonate solution, and the degummed silk was rinsed with purified water and dried. After drying, the mass of the degummed silk was weighed, and the degumming rate was calculated to be 27.7%.

[0097] 2) Spinning solution preparation

[0098] The dissolving solution is prepared according to the ratio of 1% praseodymium chloride mass fraction and 5% calcium chloride mass fraction in the solvent, and a clear and transparent dissolving solution is obtained after sufficient stirring. The degummed silk is added to the dissolving solution, and a spinning solution with a concentration of 15% is obtained after sufficient dissolution.

[0099] 3) Preparation of coagulation bath

[0100] A coagulation bath with an ethanol concentration of 60% and a glycerol concentration of 3% was prepared by volume.

[0101] 4) Spinning

[0102] A 7-channel aluminum alloy chip is used, and a microinjection pump is used as the power source to squeeze the spinning into the chip. After passing through the fine needle at the rear end of the chip, the spinning solution is squeezed into the coagulation bath to form primary fibers. After solvent exchange in the coagulation bath, multiple primary fibers are stretched onto the first stretching roller. After being fully stretched between differential stretching rollers with a total stretching multiple of 6 times, regenerated silk fibroin multifilament long fibers with a certain stress strain are obtained on the collecting roller.

[0103] 5) Test characterization

[0104] The mechanical properties of the obtained regenerated silk fibroin multifilament were tested, and the results were as follows: Figure 7 As shown, each line of different colors represents a different sample, where the stress is 495.1±17.8MPa and the strain is 23.4±5.4%.

[0105] Example 7

[0106] 1) Silk degumming

[0107] Cut the pupal silk and cut it into pieces. Put the silk into a 0.05% sodium carbonate solution, boil to degum the silk, and then rinse it with purified water in a flowing water and dry it. After drying, weigh the mass of the degummed silk, and calculate that the degumming rate is 27.5%.

[0108] 2) Preparation of spinning solution

[0109] Prepare dissolution solutions with the mass fractions of lanthanum chloride: calcium chloride in the solvent being 0%, 6%; 1%, 5%; 2%, 4%; 3%, 3%; 6%, 0% respectively. After fully stirring, obtain a completely dissolved dissolution solution. Add the degummed silk to the clear and transparent dissolution solution, and obtain a spinning solution with a concentration of 13% after full dissolution.

[0110] 3) Preparation of coagulation bath

[0111] Prepare a coagulation bath with an ethanol concentration of 50% and a glycerol concentration of 5% by volume ratio.

[0112] 4) Spinning

[0113] Use a 10-channel aluminum alloy chip, with a plunger pump as the power source, suck the spinning solution into the chip. After passing through the fine needle at the rear section of the chip, the spinning solution is extruded into the coagulation bath to form nascent fibers. After the solvent exchange of multiple nascent fibers in the coagulation bath, they are drawn to the first stretching roller, and are fully stretched between the differential stretching rollers with a total stretching multiple of 6 times, and then a regenerated silk fibroin multifilament long fiber with a certain stress-strain is obtained on the collecting roller.

[0114] 5) Testing and characterization

[0115] Conduct mechanical property tests on the obtained regenerated silk fibroin multifilament long fiber, and the stress is shown in Table 1.

[0116] Table 1 Mechanical properties of fibers prepared with different rare earth La 3+ and Ca 2+ Proportions

[0117] .

[0118] The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also make various changes. All simple, equivalent changes and modifications made according to the claims and the content of the specification of the present invention application shall fall within the scope of the protection of the claims of the present invention patent. Those not described in detail in the present invention are all conventional technical contents.

Claims

1. A method for preparing rare earth ion reinforced silk protein fibers for absorbable surgical sutures, characterized in that: The following steps are involved: S1: degumming the silk in a 0.05% sodium carbonate solution to remove sericin, thereby obtaining degummed silk with a degumming rate of 25.7%; S2: preparing a dissolving solution composed of 1% LaCl3, 5% CaCl2 and an organic solvent, dissolving the degummed silk in the dissolving solution to obtain a spinning solution with a concentration of 13%; the organic solvent is one or more of formic acid, hexafluoroisopropanol and trifluoroacetic acid; the source of the rare earth ions is LaCl3 without crystal water; the dissolved state of the rare earth ions is incomplete dissolution; S3: using a metering device to squeeze or suck the spinning solution into the multi-channel spinning chip to ensure uniform distribution of the spinning solution; S4: After the spinning solution is extruded through the chip, it enters a coagulation bath containing 50% ethanol and 5% glycerol to form multiple strands of fiber fibrils; S5: After the multiple strands of fiber fibrils come out of the coagulation bath, they are subjected to differential stretching treatment by stretching rollers, wherein the stretching multiple of the differential stretching is 6.5 times, and finally a rare earth ion reinforced silk protein fiber is obtained on a collecting roller.

2. The preparation method according to claim 1, characterized in that: In step S1, the silk raw material is natural silk or waste silk obtained after natural silk cocoons are de-pupaed, and the natural silk cocoons are one or both of mulberry silk cocoons and tussah silk cocoons.

3. A rare earth ion reinforced silk protein fiber prepared by the preparation method according to any one of claims 1 to 2.

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