A solution-driven collagen-based artificial muscle, its preparation method and application

Abstract

This invention discloses a solution-driven collagen-based artificial muscle, its preparation method, and its application. The preparation method of the artificial muscle includes the following steps: dissolving collagen powder in water, adding acetic acid to swell the solution, and mixing thoroughly to obtain a collagen solution; preparing a coagulation bath; adding the collagen solution to the coagulation bath, and obtaining collagen fibers through wet spinning; subsequently, twisting and shaping the obtained collagen fibers to obtain the solution-driven collagen-based artificial muscle. This invention, by combining wet spinning and twisting techniques, prepares a collagen-based artificial muscle with both excellent mechanical properties and good biocompatibility. This muscle exhibits high flexibility, long cycle life, fast response speed, and high strain. The entire preparation process is simple to operate, and the raw materials are inexpensive and readily available.

Description

Technical Field

[0001] This invention belongs to the field of fiber-based artificial muscle technology, and particularly relates to a solution-driven collagen-based artificial muscle, its preparation method, and its application. Background Technology

[0002] Artificial muscles can simulate the high-power energy output of biological muscles, breaking through the rigid limitations of traditional actuators and providing a more convenient and flexible new driving method. Currently, most artificial muscles are fibrous soft actuators, capable of converting external stimuli such as electricity, light, and heat into macroscopic mechanical motion. Unlike the large-scale bending deformation of film-based actuators, artificial muscles mainly achieve actuation through linear contraction, torsion, or a combination of both. Among them, helical artificial muscles, when stimulated by external stimuli, will generate torsional motion due to volume expansion, accompanied by axial expansion and contraction. This helical structure is usually formed by applying torsional force after the fibers are prepared, causing the fibers to tightly wrap. When environmental stimuli act on this type of helical fiber, the pretension stored inside is released, thereby converting into radial rotation and axial contraction motion.

[0003] Currently, artificial muscles are primarily driven through thermal and electrical response mechanisms, thus typically requiring polymer fibers with high coefficients of thermal expansion or lightweight, flexible electrode materials. However, these artificial muscles often only achieve a single mode of movement and are limited by the inherent performance limitations of the materials, thereby restricting their application potential. Therefore, developing biocompatible, environmentally friendly, and low-cost responsive materials, and achieving more diverse energy conversion methods, has become a crucial challenge that urgently needs to be overcome in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a solution-driven collagen-based artificial muscle, its preparation method, and its application, thereby solving the technical problems of limited movement modes and application scenarios of artificial muscles in existing technologies.

[0005] The objective of this invention is achieved through the following technical solution: A method for preparing solution-driven collagen-based artificial muscle includes the following steps: Collagen powder is dissolved in water, swollen with acetic acid, and then mixed evenly to obtain a collagen solution; the amount of collagen powder added to the water is 10~30mg / mL; Polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 are dissolved in water and mixed evenly to obtain a coagulation bath. The collagen solution is added to the coagulation bath, and collagen fibers are obtained by wet spinning; then the obtained collagen fibers are twisted and shaped to obtain the solution-driven collagen-based artificial muscle.

[0006] In this invention, a collagen solution is first prepared as the spinning solution, and a coagulation bath is prepared. The spinning solution is injected into the coagulation bath via wet spinning to obtain collagen fiber filaments. Subsequently, the fiber filaments are twisted and shaped to ultimately produce a solution-driven collagen-based artificial muscle. This artificial muscle can produce radial rotation and axial contraction under stimulation by water and ethanol. It should be noted that untwisted raw collagen fibers only undergo diameter changes in solution, without any contraction or rotation. After twisting, the fibers form a helical structure, and the internal pretension is released under solution stimulation, thereby driving radial rotation and axial contraction.

[0007] Preferably, in the preparation step of the collagen solution, the mass ratio of acetic acid to collagen powder is 5:2.

[0008] Preferably, the collagen powder is type I bovine Achilles tendon collagen.

[0009] This invention is the first to use type I collagen derived from bovine Achilles tendon as the collagen raw material. This material exhibits good biocompatibility, controllable degradation properties, and excellent environmental responsiveness. When applied to the human body, it can effectively reduce immune rejection, thereby expanding the application prospects of artificial muscles in medicine, tissue engineering, and biomimetic materials. Furthermore, the collagen-based artificial muscle prepared by this invention demonstrates excellent flexibility, long cycle life, rapid response speed, and high strain capacity, significantly outperforming solution-driven artificial muscles reported in the prior art in terms of overall performance.

[0010] Bovine Achilles tendon type I collagen has a larger molecular weight and a more intact structure, which better maintains its bioactivity. Compared to fish collagen, it has better thermal stability and is less prone to denaturation during processing and medical applications, thus preserving its functional integrity. Furthermore, the production process for bovine Achilles tendon type I collagen is relatively mature; the traditional acid-enzyme extraction technique not only ensures process stability but also yields a high-purity product. In contrast, the extraction process of marine collagen is easily limited by the source of raw materials, such as the compositional differences between different fish species and potential contamination risks, affecting the stability of its large-scale production and clinical application.

[0011] Preferably, in the preparation step of the coagulation bath, the concentration of polyethylene glycol (PEG) is 100-120 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES) is 6-7.5 mg / mL, the concentration of NaCl is 7-8.5 mg / mL, the concentration of Na2HPO4 is 12-13.5 mg / mL, and the concentration of NaH2PO4 is 4-5 mg / mL; more preferably, the concentration of polyethylene glycol is 110 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6.86 mg / mL, the concentration of NaCl is 8 mg / mL, the concentration of Na2HPO4 is 12 mg / mL, and the concentration of NaH2PO4 is 4 mg / mL.

[0012] In this invention, the main component of the coagulation bath is PEG, which serves to coagulate the collagen solution in the bath. The concentration of PEG affects the diameter and coagulation rate of the collagen fibers; generally, the higher the concentration, the larger the fiber diameter and the faster the coagulation rate. Furthermore, TES, NaCl, Na₂HPO₄, and NaH₂PO₄ are primarily used to adjust the pH value of the coagulation bath, and changes in pH value affect the fiber morphology and coagulation rate.

[0013] Preferably, in the collagen fiber preparation step, the collagen solution is added to the coagulation bath at a rate of 0.10~0.50 mL / min using a syringe, the rotation speed of the wet spinning collection device is 5~30 r / min, and the wet spinning temperature is 25~50℃.

[0014] Preferably, the needle diameter of the syringe is 0.06~1.65 mm.

[0015] Preferably, the motor speed during the twisting process is 300 r / min, and the twist degree is 2000~5000 r / m.

[0016] Preferably, the shaping process is performed at room temperature.

[0017] The solution-driven collagen-based artificial muscle prepared by the above-described method is a solution-driven collagen-based artificial muscle.

[0018] The above-mentioned solution-driven collagen-based artificial muscles are used in the preparation of medical, tissue engineering, and biomimetic materials.

[0019] Compared with the prior art, the beneficial effects of the present invention include: (1) This invention combines wet spinning and twisting techniques to prepare collagen-based artificial muscles with excellent mechanical properties and good biocompatibility. The muscles exhibit high flexibility, long cycle life, fast response speed, and high strain. The entire preparation process is simple to operate, and the raw materials are inexpensive and readily available.

[0020] (2) The collagen-based artificial muscle prepared by this invention can achieve rapid and reversible contraction and rotation in different solution environments; at the same time, it can also be used to prepare medical materials such as wound dressings, medical sutures, and skin tension reducers. Under the stimulation of water or ethanol, the material can quickly contract and cover the wound, thereby accelerating skin healing and preventing infection. This artificial muscle constructed from natural biomaterials shows great application potential in the fields of medicine, tissue engineering, and biomimetic materials. Attached Figure Description

[0021] Figure 1 The images shown are SEM images of the collagen fibers prepared in Example 1, where image a has a magnification of 300x and image b has a magnification of 20.0kx.

[0022] Figure 2 These are ultra-depth-of-field microscopic images of the solution-driven collagen-based artificial muscle prepared in Example 1 in different solutions. In the images, a corresponds to deionized water with a magnification of 100x, and b corresponds to ethanol with a magnification of 100x.

[0023] Figure 3 The figure shows the driving performance response curves of the solution-driven collagen-based artificial muscle prepared in Example 1 under stimulation with deionized water and ethanol, where a corresponds to deionized water and b corresponds to ethanol.

[0024] Figure 4 The results of the cyclic driving performance test of the solution-driven collagen-based artificial muscle prepared in Example 1 under no-load conditions and under alternating stimulation with ethanol and deionized water are shown. Among them, a is the strain-time curve of the artificial muscle during 50 driving cycles, and b is the strain-time curve of a single driving cycle.

[0025] Figure 5 The images shown are ultra-depth-of-field microscopic images of the collagen fibers prepared in Comparative Example 1 under different environments. In the images, a corresponds to the air environment with a magnification of 100x, b corresponds to the water environment with a magnification of 100x, and c corresponds to the ethanol environment with a magnification of 100x.

[0026] Figure 6 The results of driving performance tests of collagen fibers (cut into 10 cm samples) prepared in Comparative Example 1 under stimulation with deionized water and ethanol are shown, where a corresponds to deionized water stimulation and b corresponds to ethanol stimulation. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] In all examples and comparative examples, glacial acetic acid was used, anhydrous ethanol was used, and polyethylene glycol was PEG20000.

[0029] Example 1 A method for preparing solution-driven collagen-based artificial muscle, comprising the following steps: (1) Dissolve 0.2g of type I bovine Achilles tendon collagen powder in 10mL of deionized water, add 0.5g of acetic acid to swell, and obtain a collagen solution by mechanical stirring for 24 h; (2) Dissolve polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 in water and mix them evenly to obtain a coagulation bath; wherein the concentration of polyethylene glycol is 110 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6.86 mg / mL, the concentration of NaCl is 8 mg / mL, the concentration of Na2HPO4 is 12 mg / mL and the concentration of NaH2PO4 is 4 mg / mL; (3) The collagen solution was injected into the coagulation bath through a syringe with a needle diameter of 1.55 mm. The injection rate of the collagen solution was 0.16 mL / min, the rotation speed of the collection device was 20 r / min, and the spinning temperature was 37℃. Collagen fibers with a diameter of 245 μm were prepared by wet spinning. (4) Cut 10cm of the collagen fiber obtained in step (3) and fix one end, connect the other end to a rotary motor, and twist it at a speed of 280r / min to prepare a sample with a twist of 2800r / m. After shaping at room temperature, the solution-driven collagen-based artificial muscle is obtained.

[0030] Figure 1 SEM images of the collagen fibers prepared in Example 1 are shown, where image a has a magnification of 300x and image b has a magnification of 20.0kx. Figure 1 It can be seen that the microstructure of the collagen fibers exhibits a distinct periodic band structure.

[0031] Figure 2 These are ultra-depth-of-field microscopic images of the solution-driven collagen-based artificial muscle prepared in Example 1 in different solutions, where a corresponds to deionized water at 100x magnification and b corresponds to ethanol at 100x magnification. Figure 2It can be seen that the artificial muscle exhibits a regular and tight spiral structure in deionized water, while it undergoes untwisting and elongation in ethanol, resulting in an increase in the distance between each spiral coil.

[0032] The driving performance of the solution-driven collagen-based artificial muscle prepared in Example 1 under water and ethanol stimulation was tested, and the experimental results are as follows: Figure 3 As shown in the figure, where a corresponds to deionized water and b corresponds to ethanol. During the experiment, one end of the artificial muscle was fixed, and the other end was connected to a 100 mg weight and allowed to hang naturally. The results showed that under ethanol stimulation, the artificial muscle rapidly rotated, and its helical structure gradually unfolded within 45 seconds, resulting in the fiber length increasing to twice its original length; while under deionized water stimulation, the artificial muscle completed its twisting and returned to its initial length within 15 seconds. These results indicate that the artificial muscle has good reversible driving performance and rapid response capability.

[0033] The solution-driven collagen-based artificial muscle prepared in Example 1 was subjected to cyclic driving performance testing in ethanol-water under no-load conditions. The specific testing procedure was as follows: At the start of the experiment, a weight was attached to the bottom of the artificial muscle, which was then completely immersed in water. Since the artificial muscle in its dry state undergoes radial expansion and longitudinal contraction upon absorbing water (but not untwisting-rewinding), it was necessary to wait until its length stabilized before rapidly transferring it to the ethanol solution. The time required for the artificial muscle to stop rotating and elongating from immersion in ethanol was recorded, with an average of 45 seconds. After the strain process in ethanol ended, the artificial muscle was immediately re-immersed in deionized water, and the time from immersion to stopping rotation and contraction was recorded, with an average of 15 seconds. A total of 49 cyclic experiments were then conducted, with the solution being changed alternately each time according to the above procedure. Throughout the process, the experimental conditions were kept consistent, and the strain time and deformation were recorded each time. The average value was taken as the final result.

[0034] Test results are as follows Figure 4 As shown, a is the strain-time curve of the muscle during 50 driving cycles, and b is the strain-time curve of a single driving cycle; from Figure 4 It can be seen that the artificial muscle exhibits stable performance during 50 driving cycles, with both driving strain and response speed remaining good. Under ethanol stimulation, the artificial muscle rapidly rotates, and its helical structure gradually unfolds within 45 seconds; while in deionized water, it only takes 15 seconds to complete the twisting and return to its initial length.

[0035] Example 2 A method for preparing solution-driven collagen-based artificial muscle, comprising the following steps: (1) Dissolve 0.2g of type I bovine Achilles tendon collagen powder in 10mL of deionized water, add 0.5g of acetic acid to swell, and obtain a collagen solution by mechanical stirring for 24 h; (2) Dissolve polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 in water and mix them evenly to obtain a coagulation bath; wherein the concentration of polyethylene glycol is 110 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6.86 mg / mL, the concentration of NaCl is 8 mg / mL, the concentration of Na2HPO4 is 12 mg / mL and the concentration of NaH2PO4 is 4 mg / mL; (3) The collagen solution was injected into the coagulation bath through a syringe with a needle diameter of 1.36 mm. The injection rate of the collagen solution was 0.16 mL / min, the rotation speed of the collection device was 20 r / min, and the spinning temperature was 37℃. Collagen fibers with a diameter of 195 μm were prepared by wet spinning. (4) Cut the collagen fiber obtained in step (3) into 10cm pieces, fix one end, connect the other end to a rotary motor, and twist it at a speed of 330r / min to prepare a sample with a twist of 3300r / m. After shaping at room temperature, the solution-driven collagen-based artificial muscle is obtained.

[0036] Example 3 A method for preparing solution-driven collagen-based artificial muscle, comprising the following steps: (1) Dissolve 0.2g of type I bovine Achilles tendon collagen powder in 10mL of deionized water, add 0.5g of acetic acid to swell, and obtain a collagen solution by mechanical stirring for 24 h; (2) Dissolve polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 in water and mix them evenly to obtain a coagulation bath; wherein the concentration of polyethylene glycol is 110 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6.86 mg / mL, the concentration of NaCl is 8 mg / mL, the concentration of Na2HPO4 is 12 mg / mL and the concentration of NaH2PO4 is 4 mg / mL; (3) The collagen solution was injected into the coagulation bath through a syringe with a needle diameter of 1.25 mm. The injection rate of the collagen solution was 0.16 mL / min, the rotation speed of the collection device was 20 r / min, and the spinning temperature was 37℃. Collagen fibers with a diameter of 170 μm were prepared by wet spinning. (4) Cut 10cm of the collagen fiber obtained in step (3) and fix one end, connect the other end to a rotary motor, and twist it at a speed of 400r / min to prepare a sample with a twist of 4000r / m. After shaping at room temperature, the solution-driven collagen-based artificial muscle is obtained.

[0037] Example 4 A method for preparing solution-driven collagen-based artificial muscle, comprising the following steps: (1) Dissolve 0.2g of type I bovine Achilles tendon collagen powder in 10mL of deionized water, add 0.5g of acetic acid to swell, and obtain a collagen solution by mechanical stirring for 24 h; (2) Dissolve polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 in water and mix them evenly to obtain a coagulation bath; wherein the concentration of polyethylene glycol is 110 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6.86 mg / mL, the concentration of NaCl is 8 mg / mL, the concentration of Na2HPO4 is 12 mg / mL and the concentration of NaH2PO4 is 4 mg / mL; (3) The collagen solution was injected into the coagulation bath through a syringe with a needle diameter of 1.10 mm. The injection rate of the collagen solution was 0.16 mL / min, the rotation speed of the collection device was 20 r / min, and the spinning temperature was 37℃. Collagen fibers with a diameter of 150 μm were prepared by wet spinning. (4) Cut the collagen fiber obtained in step (3) to 10 cm and fix one end, connect the other end to a rotary motor, and twist it at a speed of 450 r / min to prepare a sample with a twist of 4500 r / m. After shaping at room temperature, the solution-driven collagen-based artificial muscle is obtained.

[0038] Comparative Example 1 A method for preparing collagen fibers, with the following specific steps: (1) Dissolve 0.2g of type I bovine Achilles tendon collagen powder in 10mL of deionized water, add 0.5g of acetic acid to swell, and obtain a collagen solution by mechanical stirring for 24 h; (2) Dissolve polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 in water and mix them evenly to obtain a coagulation bath; wherein, the concentration of polyethylene glycol is 110 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6.86 mg / mL, the concentration of NaCl is 8 mg / mL, the concentration of Na2HPO4 is 12 mg / mL and the concentration of NaH2PO4 is 4 mg / mL; (3) The collagen solution was injected into the coagulation bath through a syringe with a needle diameter of 1.55 mm. The injection rate of the collagen solution was 0.16 mL / min, the rotation speed of the collection device was 20 r / min, and the spinning temperature was 37℃. Collagen fibers with a diameter of 245 μm were prepared by wet spinning.

[0039] Figure 5 The images shown are ultra-depth-of-field microscopic images of the collagen fibers prepared in Comparative Example 1 under different environments. In these images, a corresponds to the air environment (100x magnification), b corresponds to the underwater environment (100x magnification), and c corresponds to the ethanol environment (100x magnification). Figure 5 It can be seen that untwisted collagen fibers only change in diameter in water and ethanol environments. The fiber diameter becomes thicker in water and thinner when placed in ethanol. Throughout the process, the fiber length remains basically unchanged. In addition, the comparison between air and ethanol shows that the fiber diameter is slightly larger in the ethanol environment than in the air.

[0040] The collagen fibers prepared in Comparative Example 1 were cut into 10 cm samples and their driving performance was tested under stimulation with deionized water and ethanol. The experimental results are as follows: Figure 6 As shown, a corresponds to deionized water stimulation, and b corresponds to ethanol stimulation. During the experiment, one end of the fiber was fixed, and the other end was connected to a 200 mg weight and allowed to hang naturally. The results showed that the collagen fiber only exhibited diameter changes in the two solutions: the fiber diameter increased in water and decreased in ethanol; however, no obvious stretching or rotational behavior was observed.

[0041] Under the condition of suspending a certain mass weight, the driving performance of the artificial muscles prepared in Examples 1-4 and the collagen fibers prepared in Comparative Example 1 under ethanol stimulation was tested. The test results are shown in Table 1.

[0042] Table 1. Drive performance test results

[0043] As shown in Table 1, comparing Examples 1-4, it was found that as the diameter of the syringe needle gradually decreased, the diameter of the obtained collagen fibers also decreased, and the driving strain of the artificial muscle showed a downward trend. This is because the mechanical properties are reduced due to the decrease in fiber diameter. Furthermore, comparing the driving performance of Example 1 under different weight load conditions, it was found that the driving strain of the artificial muscle without load was lower than the strain value when a 100 mg weight was suspended. This is because, under no-load conditions, the collagen-based artificial muscle will have some bending during driving, while the suspended weight will straighten the artificial muscle, keeping the fibers in a straight state, thereby improving its driving performance. However, as the mass of the weight further increases, the driving strain decreases instead, and excessive load may even damage the helical structure of the artificial muscle, causing irreversible damage.

[0044] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing solution-driven collagen-based artificial muscle, characterized in that, Includes the following steps: Collagen powder is dissolved in water, swollen with acetic acid, and then mixed evenly to obtain a collagen solution; the amount of collagen powder added to the water is 10~30mg / mL; Polyethylene glycol, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, NaCl, Na2HPO4 and NaH2PO4 are dissolved in water and mixed evenly to obtain a coagulation bath. The collagen solution is added to the coagulation bath, and collagen fibers are obtained by wet spinning; then the obtained collagen fibers are twisted and shaped to obtain the solution-driven collagen-based artificial muscle. The twisting method is as follows: cut a 10cm section of the collagen fiber, fix one end, connect the other end to a rotary motor, and twist it at a speed of 280r / min, 300r / min, 330r / min, 400r / min, or 450r / min to prepare a sample with a twist of 2000~5000r / m. In the preparation step of the collagen solution, the mass ratio of acetic acid to collagen powder is 5:2; The collagen powder is type I bovine Achilles tendon collagen; In the preparation step of the coagulation bath, the concentration of polyethylene glycol is 100~120 mg / mL, the concentration of N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is 6~7.5 mg / mL, the concentration of NaCl is 7~8.5 mg / mL, the concentration of Na2HPO4 is 12~13.5 mg / mL, and the concentration of NaH2PO4 is 4~5 mg / mL; In the preparation step of collagen fibers, the collagen solution is added to the coagulation bath at a rate of 0.10~0.50 mL / min using a syringe, the rotation speed of the wet spinning collection device is 5~30 r / min, and the temperature of wet spinning is 25~50℃. The syringe needle has a diameter of 0.06~1.65 mm.

2. The method for preparing solution-driven collagen-based artificial muscle according to claim 1, characterized in that, The shaping process is carried out at room temperature.

3. Solution-driven collagen-based artificial muscle prepared by the method of any one of claims 1 to 2.

4. The application of the solution-driven collagen-based artificial muscle of claim 3 in the preparation of medical, tissue engineering or biomimetic materials.

Images