Composite fiber and preparation method and application thereof

Abstract

The invention discloses a composite fiber as well as a preparation method and application thereof. The composite fiber comprises a fiber core and a coating layer coating the surface of the fiber core, the fiber core comprises a porous carrier and a bioactive substance loaded on the porous carrier; the bioactive substance is selected from at least one of platelet-enriched plasma and embryonic stem cell secretions; the material of the coating layer is selected from at least one of chitosan, sodium alginate, collagen and hyaluronic acid. The composite fiber comprises the fiber core and the coating layer, and the coating layer can protect the bioactive substances in the fiber core, prevent the bioactive substances from being damaged during use or storage and can also protect the bioactive substances from being broken in the freeze-drying process, so that the loading capacity of the bioactive substances in the composite fiber is high, and the service life of the composite fiber is prolonged. The platelet loss rate is low, the sustained release property and the long-acting storage property are realized, and the effective storage of 12 months can be realized.

Description

Technical Field

[0001] The invention belongs to the field of materials, and in particular relates to a composite fiber and a preparation method and application thereof. Background Art

[0002] At present, medical fiber dressings are mainly alginate fibers, sodium carboxymethyl cellulose fibers, chitosan fibers, etc. prepared by wet spinning technology. In order to improve the performance of medical fiber dressings, silver ions, EDTA, functional drugs, etc. are introduced into the medical fiber dressings, and the clinical therapeutic effect of medical fiber dressings is improved by fiber loading.

[0003] Medical fiber dressings produced by existing methods have single functions and slow therapeutic effects. As chronic wounds become more and more complex, the requirements for the versatility of dressings are getting higher and higher. However, the fiber dressings produced by wet spinning technology have a single structure, and during the preparation process, they will also cause the drug to fall off when passing through the coagulation bath. During the freeze-drying process, their performance is easily destroyed by the formation of ice crystals, which leads to low drug loading in the medical fiber dressings. Active drugs cannot be preserved for a long time due to exposure and other problems. These problems have greatly limited the large-scale promotion and use of medical fiber dressings. Summary of the invention

[0004] In order to overcome at least one technical problem existing in the above-mentioned prior art, one of the objectives of the present invention is to provide a composite fiber.

[0005] A second object of the present invention is to provide a method for preparing composite fibers.

[0006] A third object of the present invention is to provide a fiber dressing.

[0007] A fourth object of the present invention is to provide the use of the composite fiber and / or the fiber dressing in the preparation of a wound topical medicament.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] The first aspect of the present invention provides a composite fiber, which includes a fiber core and a coating layer coated on the surface of the fiber core; the fiber core includes a porous carrier and a bioactive substance loaded on the porous carrier; the bioactive substance is selected from at least one of platelet-rich plasma and embryonic stem cell secretions; the material of the coating layer is selected from at least one of chitosan, sodium alginate, collagen, and hyaluronic acid.

[0010] In the present invention, the material of the coating layer has a certain antibacterial effect and does not directly contact the biologically active substance, especially when the cationic ions such as chitosan are used as the outermost layer, it has a better antibacterial effect. The coating layer can also provide protection for the biologically active substance (such as platelet-rich plasma, embryonic stem cell secretion, etc.) during the freeze-drying process to avoid the formation of ice crystals during the freezing process to destroy the activity of the biologically active substance.

[0011] Preferably, the material of the porous carrier is selected from at least one of gelatin, sodium alginate, hyaluronic acid, polyvinyl alcohol, and polyvinyl pyrrolidone. The porous carrier in the present invention is made by wet spinning of materials with good biocompatibility. It has good compatibility with bioactive substances and will not destroy the activity of bioactive substances. In the freeze-drying process of preparing the fiber core, ice crystals directly sublimate, and a porous structure can be formed after drying, providing a large amount of attachment surface for bioactive substances. In addition, the composite fiber in the present invention has a coating layer, which can provide a protective barrier for bioactive substances, prevent direct contact between bioactive substances and the outside world, and preserve greater activity of bioactive substances.

[0012] Preferably, the coating layer comprises an outer layer and a middle layer; the material of the outer layer is selected from at least one of chitosan and collagen; the material of the middle layer is selected from at least one of sodium alginate and hyaluronic acid.

[0013] Preferably, the fiber core also includes a protective agent. The protective agent can stabilize the membrane protein components of the bioactive substance during the freeze-drying process, prevent further formation of ice crystals, and play a protective role. The protective agent binds to the surface membrane protein of the bioactive substance during the freezing process, prevents the formation of ice crystals on the surface of the bioactive substance, and plays a protective role. In addition, the protective agent forms hydrogen bonds with the biomacromolecules in the bioactive substance during the drying process, acting as water to maintain the steady state of the bioactive substance. Reduce the loss of the bioactive substance during the freeze-drying process.

[0014] Preferably, the protective agent includes at least one of trehalose and mannitol.

[0015] Preferably, the water absorption rate of the composite fiber is 700-1400%.

[0016] Preferably, the water retention rate of the composite fiber is 400-1300%.

[0017] Preferably, the swelling ratio of the composite fiber is 600-1400%.

[0018] The second aspect of the present invention provides a method for preparing the composite fiber according to the first aspect of the present invention, comprising the following steps:

[0019] S1: preparing the fiber core spinning solution and the cladding layer spinning solution respectively;

[0020] S2: wet spinning the fiber core spinning solution and the cladding layer spinning solution, and then coagulating to obtain a sheath-core fiber;

[0021] S3: freeze-drying the core-sheath fiber to obtain the composite fiber.

[0022] Preferably, the method for preparing the fiber core spinning solution is: mixing the raw materials for preparing the porous carrier, the bioactive substance, and the solvent at 30-50° C. to obtain the fiber core spinning solution.

[0023] Preferably, the method for preparing the coating layer spinning solution is: mixing the raw materials for preparing the coating layer and the solvent at 30-50° C. to obtain the coating layer.

[0024] Preferably, the coating layer spinning solution is prepared by mixing the outer layer material and the middle layer material with a solvent respectively to obtain the outer layer spinning solution and the middle layer spinning solution.

[0025] Preferably, the solvent comprises water.

[0026] Preferably, the mixing rate is 300-800 rpm.

[0027] Preferably, the step S2 is: spinning the fiber core spinning solution and the cladding layer spinning solution by a double-channel coaxial nozzle of wet spinning, and then coagulating in a coagulation bath to obtain the sheath-core fiber.

[0028] Preferably, the step S2 is: spinning the fiber core spinning solution, the outer layer spinning solution and the middle layer spinning solution by a three-channel coaxial nozzle of wet spinning, and then coagulating in a coagulation bath to obtain the sheath-core fiber.

[0029] Preferably, the freezing temperature is -20 to -198° C. The lower the freezing temperature, the shorter the freezing time.

[0030] Preferably, the drying temperature does not exceed -50° C. If the drying temperature is higher than -50° C., the fiber structure may collapse.

[0031] The third aspect of the present invention provides a fiber dressing, comprising the composite fiber described in the first aspect of the present invention.

[0032] The fourth aspect of the present invention provides use of the composite fiber described in the first aspect of the present invention and / or the fiber dressing described in the third aspect of the present invention in the preparation of a wound topical medicament.

[0033] The beneficial effects of the present invention are as follows: the composite fiber of the present invention comprises a fiber core and a coating layer, the coating layer can protect the bioactive substance in the fiber core to prevent the bioactive substance from being damaged during use or storage, and can also protect the bioactive substance from being broken during the freeze-drying process. Therefore, the composite fiber has a high loading amount of bioactive substances, a low platelet loss rate, sustained release and long-term storage properties, and can achieve effective storage for up to 12 months.

[0034] The preparation method of the present invention prepares the composite fiber through a coaxial nozzle of wet spinning, and the preparation method is simple and easy to promote and apply.

[0035] The fiber dressing of the present invention has a good effect in treating traumatic wounds. During use, it can quickly degrade and release a large amount of VEGF growth factor continuously, inhibit infection around the wound, promote the growth and recovery of wound tissue, and significantly shorten the wound healing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a test chart of the antibacterial effect of the medical fiber dressing prepared in Example 1.

[0037] Figure 2 2 are SEM images of the medical fiber dressings in Comparative Example 1 and Example 1.

[0038] Figure 3 This is a graph showing the release curve of vascular endothelial growth factor (VEGF) from PRP in vitro in the medical dressings of Comparative Example 1 and Example 1.

[0039] Figure 4 It is a test chart of platelet loss rate of the medical dressings in Example 1 and Comparative Examples 1-2.

[0040] Figure 5 It is the safety test diagram of the medical fiber dressing of Example 1-2.

[0041] Figure 6 The graphs are test results of the medical fiber dressings of Examples 1 to 2 on the release of platelet-derived growth factor (PDGF) growth factor from PRP in vitro.

[0042] Figure 7 It is a diagram of the healing process of the medical dressings in Comparative Example 1 and Examples 1-2.

[0043] Figure 8 It is a healing rate curve diagram of the medical dressings in Comparative Example 1 and Examples 1-2.

[0044] Fig. 9 The histological diagrams are of the wound healing process of the medical dressings in Comparative Example 1 and Examples 1-2.

[0045] Fig.10 It is a test diagram of the physical properties of the medical fiber dressings in Examples 1 to 3. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

[0047] Example 1

[0048] This example provides a method for preparing a medical fiber dressing, and the specific steps include:

[0049] (1) Collagen powder was mixed with deionized water to prepare a collagen solution with a mass percentage of 1%, and the mixture was stirred at a speed of 500 rpm and a temperature of 45° C. for 1 hour to fully mix the mixture and prepare a cortex spinning solution. The higher the concentration of the collagen solution, the thicker the outermost layer, which is more conducive to improving the sustained-release effect of the fiber.

[0050] (2) mixing sodium alginate powder with deionized water to prepare a sodium alginate solution with a mass percentage of 2%, stirring at a speed of 500 rpm and a temperature of 45° C. for 1 hour to fully mix the mixture, thereby preparing an intermediate layer spinning solution;

[0051] (3) Mixing polyvinyl pyrrolidone powder and trehalose powder with deionized water to prepare a mixed solution of polyvinyl pyrrolidone and trehalose with a total mass percentage of 1% (the mass ratio of polyvinyl pyrrolidone to trehalose is 1:1), stirring at a speed of 500 rpm and a temperature of 30° C. for 1 hour to fully mix them, and mixing the mixed solution with platelet-rich plasma (i.e., bioactive PRP) at a volume ratio of 1:2, stirring at 500 rpm for 10 minutes to fully mix them, and preparing a core spinning solution;

[0052] (4) The skin layer spinning solution, the middle layer spinning solution and the core layer spinning solution were respectively loaded into syringes and connected to a three-channel coaxial nozzle (mainly composed of three layers of channels) for wet spinning. The propulsion speeds of the spinning solutions were 90 mL / h (skin layer spinning solution), 180 mL / h (middle layer spinning solution) and 90 mL / h (core layer spinning solution). After passing through the coaxial nozzle, the spinning solution was coagulated in a 2% by mass calcium chloride solution bath to form a stable skin-core fiber.

[0053] (5) Take out the sheath-core fiber, immediately remove excess moisture on the fiber surface with filter paper, wrap it with tin foil and freeze it in liquid nitrogen for 30 minutes, then place it in a freeze dryer for drying. Set the internal temperature of the dryer to -80°C and the drying time to 48 hours to obtain the medical fiber dressing in this example.

[0054] The core layer spinning solution can form hydrogen bonds with polysaccharides (such as trehalose, mannitol, etc.) and increase viscosity. The formation of hydrogen bonds during freeze-drying also changes its glass transition temperature, which can maintain the steady state of biologically active substances.

[0055] Example 2

[0056] The preparation method of the medical fiber dressing in this example is different from that in Example 1 only in that:

[0057] In step (1), chitosan is used in this example to replace the collagen in Example 1 in equal amounts;

[0058] In step (2), in this example, hyaluronic acid is used to replace the sodium alginate in Example 1 in an equal amount;

[0059] In step (3), in this example, polyvinyl alcohol is used to replace the polyvinyl pyrrolidone in Example 1 in an equal amount, and embryonic stem cell secretion is used to replace the bioactive PRP in Example 1 in an equal amount.

[0060] Cortical collagen solution and Ca in the coagulation bath 2+ The combination can activate platelets, thereby causing platelet rupture, and chitosan solution can also cause platelet rupture. Therefore, in Examples 1 to 2 of the present invention, a three-channel coaxial nozzle is used during wet spinning, and a three-layer structure of a cortex, an intermediate layer and a core layer is used. The intermediate layer can prevent the collagen solution or chitosan solution of the cortex from contacting with the secretion of biologically active embryonic stem cells. After freeze drying, the fluidity of the secretion of biologically active embryonic stem cells and the collagen solution or chitosan solution is also reduced, so that the medical fiber dressings in Examples 1 to 2 can achieve long-term storage of up to 12 months.

[0061] Example 3

[0062] This example provides a method for preparing a medical fiber dressing, and the specific steps include:

[0063] (1) Chitosan powder was mixed with deionized water to prepare a chitosan solution with a mass percentage of 1%, and the mixture was stirred at a speed of 500 rpm and a temperature of 45° C. for 1 hour to fully mix the mixture to prepare a skin spinning solution.

[0064] (2) mixing gelatin powder with deionized water to prepare a gelatin solution with a mass percentage of 2%, stirring at a speed of 500 rpm and a temperature of 45° C. for 1 hour to fully mix, then adding trehalose to make the mass percentage of trehalose in the mixed solution 0.5%, stirring at a speed of 500 rpm and a temperature of 30° C. for 1 hour to fully mix, and mixing the mixed solution with platelet-rich plasma (i.e., bioactive PRP) at a volume ratio of 1:2, stirring at 500 rpm for 10 minutes to fully mix, and preparing a core spinning solution;

[0065] (3) The skin layer spinning solution and the core layer spinning solution are respectively loaded into syringes and connected to a two-channel coaxial nozzle (mainly composed of two layers of channels) for wet spinning. The propulsion speed of the spinning solution is 90 mL / h (skin layer spinning solution) and 180 mL / h (core layer spinning solution). After passing through the coaxial nozzle, the spinning solution passes through a coagulation bath of a 2% by mass calcium chloride solution to form a stable skin-core fiber.

[0066] (4) Take out the sheath-core fiber, immediately remove excess moisture on the fiber surface with filter paper, wrap it with tin foil and freeze it in liquid nitrogen for 30 minutes, then place it in a freeze dryer for drying. Set the internal temperature of the dryer to -80°C and the drying time to 48 hours to obtain the medical fiber dressing in this example.

[0067] Comparative Example 1

[0068] The medical dressing in this example is prepared by freezing platelet-rich plasma in liquid nitrogen for 30 minutes, and then drying it in a freeze dryer, with the internal temperature of the dryer set at -80°C and the drying time set at 48 hours.

[0069] Comparative Example 2

[0070] The only difference between the preparation method of the medical dressing in this example and that in Example 1 is that step (3) of this example does not contain trehalose.

[0071] Performance Test:

[0072] (1) Antibacterial effect test

[0073] The medical fiber dressing prepared in Example 1 was added to Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus culture dishes for antibacterial tests. The specific test results are as follows: Figure 1 As shown. Figure 1It can be seen that the medical fiber dressing in Example 1 has good antibacterial effects on Escherichia coli and Staphylococcus aureus, and obvious antibacterial circles appear during the test. After testing, the medical fiber dressings in Examples 2 to 3 have an antibacterial effect that is basically equivalent to that of Example 1.

[0074] (2) Scanning electron microscope test

[0075] The activity of PRP of the medical fiber dressings in Comparative Example 1 and Example 1 after freeze-drying was tested by scanning electron microscopy. The specific test results are as follows: Figure 2 (a) and Figure 2 (b) is shown. Figure 2 (a) It can be seen that the platelets in the simple platelet-rich plasma in Comparative Example 1 showed aggregation during freeze-drying, and a large number of platelets ruptured and lost their biological activity due to aggregation. Figure 2 (b) It can be seen that in Example 1, after PRP is loaded by wet spinning using a coaxial nozzle to prepare a medical fiber dressing, a large amount of enriched platelets can be dispersed and loaded on the core layer of the fiber. The platelets are round, the platelet membrane is not broken, and the outer layer presents a tight collagen layer, which prevents the platelets from directly contacting the outside during storage. After the medical fiber dressing in Example 1 was stored at room temperature for 12 months, its surface morphology was tested using a scanning electron microscope. Specifically, Figure 2 (c) and Figure 2 (d) Figure 2 (c) and Figure 2 (d) SEM images of platelet morphology after freeze-drying and storage for 3 months and 12 months, respectively. The scale bars are 200 nm and 2 μm, respectively. Figure 2 (c) It can be seen that with the extension of storage time, the morphology of PRP has not been significantly changed, and platelets adhere to the surface of the core material. The main reason is that trehalose can increase the viscosity between the core solution and platelets, so that platelets are stably loaded on the surface of the core material. On the other hand, trehalose can protect platelets and avoid damage to platelets during preparation and storage. Figure 2 (d) It can be seen that after 12 months of storage, some platelets became square and a small amount of platelet aggregation occurred. The number of platelets in the core layer also became relatively smaller, but there were still a large number of platelets with relatively complete morphology in the fiber layer. Therefore, long-term preservation of platelets can be achieved by fiber wrapping.

[0076] (3) Long-term storage effect test

[0077] In order to evaluate the long-term storage effect of the PRP loaded on the medical fiber dressing prepared in Example 1, the release curves of vascular endothelial growth factor (VEGF) released by PRP in vitro of the medical dressings prepared in Comparative Example 1 and Example 1 were tested respectively by Elisa enzyme-linked immunosorbent assay, wherein the release curve of vascular endothelial growth factor (VEGF) released by PRP of the medical dressing in Comparative Example 1 was tested immediately after preparation, and the release curve of vascular endothelial growth factor (VEGF) released by PRP of the medical fiber dressing in Example 1 was tested after being placed at room temperature for 0 months, 3 months, 6 months, and 12 months, and the release curve of vascular endothelial growth factor (VEGF) released by PRP in vitro for 7 days was tested respectively. The specific test results are as follows: Figure 3 As shown. Figure 3 It can be seen that after the medical fiber dressing in Example 1 was placed for 12 months, the cumulative release of growth factors in the sample within 7 days lost about 50%; while the medical dressing in Comparative Example 1 almost all PRP lost its activity. Therefore, the medical dressing prepared by the present invention has a long-term preservation effect of up to 12 months.

[0078] (4) Platelet loss rate test

[0079] In order to evaluate the protective effect of trehalose and polyvinyl pyrrolidone in the fiber dressing on the freeze-drying process of PRP loaded in the medical fiber dressing, the ELISA enzyme-linked immunosorbent assay was used to measure the release of growth factors before and after freeze-drying of PRP in the medical fiber dressing. The specific test method was: the cumulative release of VEGF from PRP in vitro was tested respectively for unfreeze-dried PRP, freeze-dried PRP (i.e., Comparative Example 1), the fiber dressing in Comparative Example 2, the sheath-core fiber prepared in step (4) of Example 1, and the fiber dressing prepared in Example 1. The specific test results are shown in Figure 2. Figure 4 As shown. Figure 4 It can be seen that in the process of preparing the core-skin fiber in Example 1, the loss of PRP is small, only about 10% is lost. Trehalose is not used in the core layer in Comparative Example 2. During the freeze-drying process, the loss of PRP is large, mainly because the platelet membrane is easily punctured by ice crystals, resulting in platelet activation and loss of activity, with a loss of about 60%. In order to reduce the damage to platelets during the freeze-drying process, Example 1 of the present invention increases the viscosity between trehalose and the platelet membrane and changes the glass transition temperature of platelets through the synergistic effect between polyvinyl pyrrolidone and trehalose, which can reduce the formation of ice crystals during the freezing process and maintain the homeostasis in the platelets. The loss rate of platelets loaded in the prepared fiber dressing is only 25%. Therefore, the medical dressing prepared by the present invention can significantly reduce the destructiveness of the freeze-drying process to platelets.

[0080] (5) Safety testing

[0081] In order to evaluate the cell viability of the medical fiber dressing, the medical fiber dressings of Example 1 and Example 2 were tested using CCK-8 assay. The specific test results are as follows: Figure 5 As shown. Figure 5 It can be seen that the number of cells increases linearly, indicating that the medical fiber dressings of Example 1 and Example 2 are non-toxic to cell growth and have high safety.

[0082] (6) Sustained release effect test

[0083] In order to evaluate the sustained release of biological activity in the fiber dressing, the ELISA enzyme-linked immunosorbent assay was used to measure the effect of PRP in the medical fiber dressings in Example 1 and Example 2 on the release of platelet-derived growth factor (PDGF) by PRP in vitro. The specific test results are as follows: Figure 6 As shown. Figure 6 It can be seen that the medical fiber dressings of Examples 1 to 2 of the present invention can still maintain the activity of PRP and can regulate the slow release of PDGF growth factor, and the slow release time can be as long as more than 10 days.

[0084] (7) Wound healing effect test

[0085] In order to evaluate the wound healing effect of fiber dressings, a full-thickness skin incision model was used to test the wound healing ability of fiber dressings. After a full-thickness skin incision was prepared on the back of rats, gauze, PRP gel (unfreeze-dried platelet-rich plasma), fiber dressings in Example 1 and Example 2 were used for treatment, and then photos were taken on the 0th day of treatment, the 7th day of treatment, the 14th day of treatment, and the 21st day of treatment. Figure 7 As shown, the wound healing rate and time curve are then calculated and plotted based on the wound area, as shown in Figure 8 As shown. Figure 7 and Figure 8 It can be seen that the epithelialization of the skin wounds of the medical fiber dressings in Examples 1 to 2 was basically completed at 21 days, indicating that the medical dressings loaded with bioactive substances through fibers can promote the epithelialization of wounds.

[0086] In order to evaluate the histological changes of fiber dressings during wound healing, a full-thickness skin incision model was used to test the wound healing ability of fiber dressings. The collagen deposition and tissue healing during the skin healing process were evaluated by histological analysis such as hematoxylin and eosin staining (H&E staining) and Masson staining. The specific test results are as follows: Fig. 9 As shown. Fig. 9 It can be seen that the wound healing quality and effect of the fiber dressings in Examples 1 to 2 are the best after 21 days of use, and the wound surface presents mature skin appendages and collagen structure, and the epidermis is almost healed.

[0087] (8) Physical properties test

[0088] In order to evaluate the physical properties of the medical fiber dressing, the degradation performance, water retention performance, swelling rate and water absorption performance of the medical fiber dressings in Examples 1 to 3 were tested respectively. The specific test results are as follows: Fig.10 As shown, Fig.10 (a) is the degradation performance test diagram, Fig.10 (b) is the water retention rate test chart, Fig.10 (c) is the swelling rate test graph, and 10(d) is the water absorption rate test graph. Fig.10 It can be seen that the degradation rate of the medical fiber dressing prepared in Example 1 reached 90% on the sixth day; the water absorption rate reached 1000%, the water retention rate reached 800%, and the swelling rate reached a maximum value of 1400% in 7 hours. The degradation rate of the medical fiber dressing prepared in Example 2 reached 90% on the seventh day; the water absorption rate reached 1400%, the water retention rate reached 1300%, and the swelling rate reached a maximum value of 1000% in 7 hours. The degradation rate of the medical fiber dressing prepared in Example 3 reached 80% on the seventh day, the water absorption rate reached 700%, the water retention rate reached 400%, and the swelling rate reached a maximum value of 600% in 7 hours. Among them, the speed of the degradation rate will affect the release speed of PRP, and the size of the swelling rate will affect the ability of the dressing to absorb wound exudate; the water absorption rate and the water retention rate indicate whether the dressing can maintain the relative moisture of the wound, which is more conducive to wound healing. The above results show that the medical fiber dressing prepared by the present invention meets the use requirements.

[0089] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A composite fiber, characterized in that: The composite fiber includes a fiber core and a coating layer coated on the surface of the fiber core; the fiber core includes a porous carrier and a bioactive substance loaded on the porous carrier; the bioactive substance is selected from at least one of platelet-rich plasma and embryonic stem cell secretion; the material of the coating layer is selected from at least one of chitosan, sodium alginate, collagen, and hyaluronic acid.

2. The composite fiber according to claim 1, characterized in that: The material of the porous carrier is selected from at least one of gelatin, sodium alginate, hyaluronic acid, polyvinyl alcohol and polyvinyl pyrrolidone.

3. The composite fiber according to claim 1, characterized in that: The coating layer comprises an outer layer and a middle layer; the material of the outer layer is selected from at least one of chitosan and collagen; the material of the middle layer is selected from at least one of sodium alginate and hyaluronic acid.

4. The composite fiber according to claim 1, characterized in that: The fiber core also includes a protective agent.

5. The composite fiber according to claim 4, characterized in that: The protective agent includes at least one of trehalose and mannitol.

6. The composite fiber according to any one of claims 1 to 5, characterized in that: The composite fiber has at least one of the following characteristics: (a) the water absorption rate of the composite fiber is 700 to 1400%; (b) the water retention rate of the composite fiber is 400 to 1300%; (c) The swelling ratio of the composite fiber is 600 to 1400%.

7. The method for preparing the composite fiber according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: preparing the fiber core spinning solution and the cladding layer spinning solution respectively; S2: wet spinning the fiber core spinning solution and the cladding layer spinning solution, and then coagulating to obtain a sheath-core fiber; S3: freeze-drying the core-sheath fiber to obtain the composite fiber.

8. The method for preparing the composite fiber according to claim 7, characterized in that: The freezing temperature is -20 to -198°C; And / or, the drying temperature does not exceed -50°C.

9. A fiber dressing, characterized in that: The composite fiber comprises the composite fiber according to any one of claims 1 to 6.

10. Use of the composite fiber according to any one of claims 1 to 6 and / or the fiber dressing according to claim 9 in the preparation of a wound topical medicament.

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