Wound dressing based on coaxial electrospun core-sheath structure and method of making the same
By constructing a core-sheath structure wound dressing through coaxial electrospinning and utilizing a combination of polycaprolactone and methacrylamide gelatin, the mechanical strength of the wound dressing and the long-term, controllable release of drugs were achieved. This solved the problems of insufficient mechanical strength, uncontrollable drug release, and instability of silver nanoparticles in existing technologies, and provided sustained antibacterial and angiogenesis-promoting effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF SHANGHAI FOR SCI & TECH
- Filing Date
- 2026-04-21
- Publication Date
- 2026-06-30
AI Technical Summary
Existing electrospun wound dressings suffer from insufficient mechanical strength, uncontrollable drug release, unstable release of silver nanoparticles, and short half-life of angiogenesis promoters, making it difficult to simultaneously address the challenges of bacterial infection and insufficient angiogenesis.
A core-sheath structure was constructed using coaxial electrospinning technology. Polycaprolactone served as the core layer loaded with deferroamine, while methacrylamide gelatin served as the sheath layer loaded with silver nanoparticles. A covalent network was formed through ultraviolet crosslinking to achieve long-term and controllable drug release and mechanical enhancement of the dressing.
It improves the mechanical properties of the dressing and the controllability of drug release, ensures the sustainability of antibacterial and angiogenesis-promoting effects, reduces the cytotoxic risk of silver nanoparticles, and provides a stable moist healing environment.
Smart Images
Figure CN122297748A_ABST
Abstract
Description
Technical Field
[0001] This invention patent relates to the field of medical materials technology, specifically to a core-sheath structure wound dressing based on coaxial electrospinning and its preparation method. Background Technology
[0002] Chronic, refractory wounds, such as diabetic foot ulcers, venous ulcers, and pressure injuries, pose a significant challenge in clinical treatment. The healing impairment of these wounds stems primarily from two core pathological factors: bacterial infection and insufficient angiogenesis. Therefore, an ideal wound dressing needs to possess both effective antibacterial capabilities and sustained angiogenesis-promoting capabilities.
[0003] Electrospinning technology can prepare nanofiber scaffolds that mimic the structure of the extracellular matrix, with high specific surface area and high porosity, and is widely used in wound dressings. Coaxial electrospinning, as an advanced technology, can prepare composite fibers with core-sheath structures, which makes it possible to load different functional active substances in sections and achieve controlled release. Currently, some studies have attempted to use coaxial electrospinning to prepare drug-loaded fibers for wound repair.
[0004] However, existing technologies still have several obvious drawbacks:
[0005] First, ordinary electrospun nanofiber membranes have poor mechanical strength and low adhesion to the skin. They are prone to structural collapse or premature detachment in humid environments, affecting their physical barrier function as dressings and their long-term retention effect.
[0006] Second, due to the high specific surface area of nanofibers, the drugs loaded on them are prone to burst release, and the release behavior is uncontrollable. This cannot meet the different requirements of drug release rate at different stages of wound healing. For example, antibacterial agents need to take effect quickly in the early stage, while growth factors need to be released slowly over a long period of time.
[0007] Third, commonly used inorganic antibacterial agents such as silver nanoparticles have unstable release in fibers, which may lead to excessively high local concentrations in the early stage, causing cytotoxicity, or insufficient release in the later stage, affecting the antibacterial effect.
[0008] Fourth, effective angiogenesis agents such as deferoxamine have extremely short half-lives in vivo, making it difficult to maintain an effective therapeutic concentration at the wound site when applied directly, thus limiting their efficacy.
[0009] Fifth, many dressings have a single function, focusing only on antibacterial properties or growth promotion, making it difficult to address the two coexisting problems of infection and insufficient blood supply.
[0010] In view of this, we propose a core-sheath structure wound dressing based on coaxial electrospinning and its preparation method.
[0011] Invention Patent Content
[0012] The purpose of this invention is to provide a core-sheath structure wound dressing based on coaxial electrospinning and its preparation method, so as to solve the problems existing in the above-mentioned background art.
[0013] To achieve the above objectives, this invention provides the following technical solution:
[0014] A core-sheath structure wound dressing based on coaxial electrospinning includes nanofibers having a core layer and a sheath layer enclosing the core layer. The core layer contains polycaprolactone and deferoxamine loaded in the polycaprolactone. The sheath layer contains methacrylamide gelatin and silver nanoparticles loaded in the methacrylamide gelatin, wherein the methacrylamide gelatin is cross-linked under ultraviolet light to form a covalent network structure.
[0015] Preferably, the mass-volume concentration of polycaprolactone in the core spinning solution is 8% to 12%, and the loading of deferoxamine (based on the total mass of the fiber membrane) is 0.25% to 0.5%.
[0016] Preferably, the methacrylamide gelatin has a mass-volume concentration of 12% to 16% in the sheath spinning solution, and the loading of silver nanoparticles (based on the total mass of the fiber membrane) is 0.5% to 0.75%.
[0017] Preferably, the silver nanoparticles have a particle size of 60 to 120 nanometers.
[0018] Preferably, the average diameter of the nanofibers is between one hundred nanometers and one thousand nanometers.
[0019] A method for preparing a core-sheath structure wound dressing based on coaxial electrospinning includes the following steps:
[0020] S1. Dissolve polycaprolactone in a first organic solvent and stir until completely dissolved to obtain a polycaprolactone solution; then add deferoxamine to the polycaprolactone solution and stir until uniformly dispersed to obtain a core spinning solution;
[0021] S2. Dissolve methacrylamide gelatin in a second organic solvent and stir until completely dissolved to obtain a methacrylamide gelatin solution; then add silver nanoparticles to the methacrylamide gelatin solution, and treat with ultrasound and stirring until uniformly dispersed to obtain a sheath spinning solution;
[0022] S3. The core spinning solution obtained in step S1 and the sheath spinning solution obtained in step S2 are injected into the inner and outer injectors of the coaxial electrospinning device, respectively. The spinning parameters are set, and coaxial electrospinning is performed. After electrospinning, the nascent fiber membrane with core-sheath structure is collected on the receiving device.
[0023] S4. Dissolve the photoinitiator in an alcohol solvent to obtain a photoinitiator solution; immerse the nascent fiber membrane obtained in step S3 in the photoinitiator solution, and then irradiate it under ultraviolet light to cause the methacrylamide gelatin to undergo a crosslinking reaction; after crosslinking is completed, wash it with an alcohol solvent and dry it in a vacuum drying oven at 40 degrees Celsius for 1 day to obtain the core-sheath structure wound dressing.
[0024] Preferably, in step S1, the first organic solvent is hexafluoroisopropanol; in step S2, the second organic solvent is trifluoroethanol.
[0025] Preferably, in step S3, the spinning parameters include: the propulsion speed of the core spinning solution, the propulsion speed of the sheath spinning solution, the applied voltage, and the distance between the receiving device and the tip of the spinning needle.
[0026] Preferably, in step S4, the photoinitiator is one of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone or phenyl-2,4,6-trimethylbenzoylphosphinic acid lithium; the alcohol solvent is ethanol, methanol or water.
[0027] Preferably, in step S4, the wavelength of the ultraviolet light is 365 nanometers, and the irradiation time is 20 to 40 minutes.
[0028] By employing the above technical solution, this invention patent provides a core-sheath structure wound dressing based on coaxial electrospinning and its preparation method. It possesses at least the following beneficial effects:
[0029] This invention patent utilizes polycaprolactone as the core skeleton material and employs coaxial electrospinning to construct a core-sheath structure, achieving a significant enhancement in the mechanical properties of wound dressings. Compared to fiber membranes made of single materials or mixed spinning, this composite structure of a "rigid and tough core layer" and a "hydrophilic sheath layer" effectively solves the common problems of poor mechanical strength and easy deformation or damage in humid environments that exist in electrospun membranes. This gives the dressing better operability and stability on the wound surface, providing lasting physical protection for wound healing.
[0030] By encapsulating deferoxamine within a hydrophobic polycaprolactone core and utilizing the slow-degradation properties of polycaprolactone, a long-lasting and controllable sustained release of deferoxamine is achieved. By loading deferoxamine into the core layer, the hydrophobic polycaprolactone matrix first forms an initial barrier for drug diffusion, effectively slowing down the early burst release of deferoxamine. As polycaprolactone slowly degrades in vivo, deferoxamine can be continuously and stably released to the wound site, thereby extending the duration of drug action from minutes to days or even weeks. This solves the key problems of severe burst release and uncontrollable release of drugs (especially growth factors), as well as the short half-life of deferoxamine itself, which makes it impossible to maintain an effective therapeutic concentration, thus ensuring the persistence of the pro-angiogenic effect.
[0031] By loading silver nanoparticles onto a methacrylamide gelatin sheath and using UV crosslinking technology to form a stable three-dimensional covalent network in the methacrylamide gelatin, effective fixation and controllable release of silver nanoparticles were achieved. The silver nanoparticles were "locked" in the crosslinked network, which greatly improved their dispersion stability in the fibers and prevented the problem of uncontrollable release caused by aggregation or excessively rapid loss. This solved the problems of unstable release and high potential cytotoxicity of silver nanoparticles. At the same time, the crosslinked sheath can release silver ions in a gentler and more durable manner, providing reliable antibacterial protection while significantly reducing the toxic risk of silver nanoparticles to normal cells.
[0032] By using methacrylamide gelatin as the sheath matrix material and implementing ultraviolet cross-linking, the hydrophilicity, morphological stability, and biocompatibility of the dressing were simultaneously optimized and improved. Methacrylamide gelatin itself is inherited from gelatin and has excellent hydrophilicity and cell affinity, which solves the problem of insufficient hydrophilicity of ordinary hydrophobic polymer dressings, which is not conducive to cell adhesion and moist healing. After ultraviolet cross-linking, its water solubility is transformed into water swelling, which can absorb wound exudate and maintain a moist environment while maintaining the integrity and morphological stability of the fiber structure, avoiding dissolution or collapse in the body fluid environment. The "hydrophilic-stable" balanced design provides an ideal biomimetic microenvironment for cell migration, proliferation, and tissue regeneration. Attached Figure Description
[0033] The accompanying drawings, which are included to provide a further understanding of the invention, form part of this application:
[0034] Figure 1 This is a schematic diagram of the preparation process of the core-sheath structure wound dressing based on coaxial electrospinning according to the present invention patent.
[0035] Figure 2 This is a diagram showing the DFOhuvec cell proliferation test results of this invention patent;
[0036] Figure 3 This is a CCK-8 result diagram of Ag-only loading according to the present invention patent;
[0037] Figure 4 This is a comparison of SEM images before and after crosslinking in this invention patent. Detailed Implementation
[0038] The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0039] See Figure 1 , Figure 2 , Figure 3 , Figure 4 This invention provides a core-sheath structure wound dressing based on coaxial electrospinning, comprising nanofibers, wherein the nanofibers have a core layer and a sheath layer enclosing the core layer, the core layer comprising polycaprolactone and deferoxamine loaded in the polycaprolactone, and the sheath layer comprising methacrylamide gelatin and silver nanoparticles loaded in the methacrylamide gelatin, wherein the methacrylamide gelatin is cross-linked under ultraviolet light to form a covalent network structure;
[0040] It should be noted that the core-sheath structure is the core design of this invention. Polycaprolactone (PCL) and deferoxamine (DFO) are placed in the core layer to utilize the excellent mechanical properties of PCL to provide structural support for the fiber membrane, and to utilize its hydrophobic and slow-degradation properties to achieve long-term, controllable sustained release of DFO, thus overcoming the clinical challenge of the short in vivo half-life of DFO. Methacrylamide gelatin (GelMA) and silver nanoparticles (Ag) are placed in the sheath layer to utilize the hydrophilicity and photocrosslinking properties of GelMA to provide a cell-friendly microenvironment, while stabilizing and fixing the Ag nanoparticles through a covalent network formed by ultraviolet crosslinking, thus solving the problems of unstable Ag release and potential cytotoxicity. This partitioned design of "core layer mechanical support and long-term healing promotion, sheath layer hydrophilic antibacterial and stable controlled release" is the key to achieving multi-functional synergy and time-sequential release.
[0041] The mass-volume concentration of polycaprolactone in the core spinning solution is 8% to 12%, and the loading of deferoxamine (based on the total mass of the fiber membrane) is 0.1% to 0.2%.
[0042] It should be noted that PCL concentration within this range can ensure that the core spinning solution has suitable viscosity and spinnability, while ensuring that the formed fiber core has sufficient mechanical strength. DFO loading within this concentration range can not only maintain an effective angiogenesis concentration at the wound site, but also avoid the cytotoxic risks that may be caused by excessive initial loading. Through the sustained-release mechanism of PCL, its duration of action can be extended from several minutes to several weeks.
[0043] The methacrylamide gelatin has a mass-volume concentration of 12% to 16% in the sheath spinning solution, and the loading of silver nanoparticles (based on the total mass of the fiber membrane) is 0.5% to 0.75%.
[0044] It should be noted that the spinning solution prepared with GelMA at this concentration has good spinnability and fiber-forming properties, and the resulting sheath structure is intact. GelMA in this concentration range can form a network of moderate density after crosslinking, which can provide effective fixation sites for Ag nanoparticles and maintain good hydrophilic swelling properties. Within this concentration range, Ag nanoparticles can provide effective and continuous antibacterial protection through contact and ion slow release. Furthermore, because they are fixed by the covalent network, the sudden release of high concentrations of Ag is avoided, thereby minimizing the risk of cytotoxicity.
[0045] The silver nanoparticles have a particle size of 60 to 120 nanometers.
[0046] The average diameter of the nanofibers is between one hundred nanometers and one thousand nanometers.
[0047] It should be noted that Ag nanoparticles with a particle size of 60 to 120 nanometers were selected based on their large specific surface area, high antibacterial efficacy, and ease of dispersion in GelMA solution. The nanofiber diameter is in the range of 100 to 1000 nanometers, which can effectively simulate the topological structure of the natural extracellular matrix, which is conducive to cell adhesion, migration and proliferation, while ensuring that the dressing has high porosity and good air and moisture permeability.
[0048] A method for preparing a core-sheath structure wound dressing based on coaxial electrospinning includes the following steps:
[0049] S1. Dissolve polycaprolactone in a first organic solvent and stir until completely dissolved to obtain a polycaprolactone solution; then add deferoxamine to the polycaprolactone solution and stir until uniformly dispersed to obtain a core spinning solution;
[0050] S2. Dissolve methacrylamide gelatin in a second organic solvent and stir until completely dissolved to obtain a methacrylamide gelatin solution; then add silver nanoparticles to the methacrylamide gelatin solution, and treat with ultrasound and stirring until uniformly dispersed to obtain a sheath spinning solution;
[0051] S3. The core spinning solution obtained in step S1 and the sheath spinning solution obtained in step S2 are injected into the inner and outer injectors of the coaxial electrospinning device, respectively. The spinning parameters are set, and coaxial electrospinning is performed. After electrospinning, the nascent fiber membrane with core-sheath structure is collected on the receiving device.
[0052] S4. Dissolve the photoinitiator in an alcohol solvent to obtain a photoinitiator solution; immerse the nascent fiber membrane obtained in step S3 in the photoinitiator solution, and then irradiate it under ultraviolet light to cause the methacrylamide gelatin to undergo a crosslinking reaction; after crosslinking is completed, wash it with an alcohol solvent and dry it in a vacuum drying oven at 40 degrees Celsius for 1 day to obtain the core-sheath structure wound dressing.
[0053] It should be noted that this preparation method combines two core processes: "coaxial electrospinning" and "UV crosslinking post-treatment." The first step, coaxial electrospinning, achieves integrated molding and precise spatial distribution of the PCL / DFO core layer and the GelMA / Ag sheath layer. The second step, UV crosslinking, is not simply curing; its key role is to covalently crosslink the methacryloyl groups of the GelMA side chains, forming a three-dimensional network. This network, on the one hand, "locks" the Ag nanoparticles within, fundamentally solving the industry problem of easy aggregation and burst release of inorganic nanoparticles in polymer carriers; on the other hand, crosslinking transforms GelMA from water-soluble to water-swellable, ensuring that the dressing maintains its structural integrity and does not dissolve when absorbing wound exudate, thus maintaining the stability of the physical barrier function.
[0054] In step S1, the first organic solvent is hexafluoroisopropanol; in step S2, the second organic solvent is trifluoroethanol.
[0055] It should be noted that hexafluoroisopropanol was chosen as the primary organic solvent for dissolving polycaprolactone (PCL) because of its excellent solubility for PCL, forming a uniform and stable solution. This ensures that the core spinning solution has suitable conductivity and viscosity, thereby guaranteeing the continuous forming and mechanical strength of the core fibers. Secondly, trifluoroethanol was specified as the secondary organic solvent for dissolving methacryloyl gelatin (GelMA) based on its good solubility for GelMA and its ability to form a good solvent miscibility system with hexafluoroisopropanol. During coaxial spinning, the jets of the core layer (PCL / hexafluoroisopropanol) and the sheath layer (GelMA / trifluoroethanol) evaporate simultaneously in the air. The matching evaporation rates of hexafluoroisopropanol and trifluoroethanol are crucial. This avoids problems such as jet instability, fiber morphology defects (e.g., beading), or incomplete core-sheath structure caused by excessive differences in the evaporation rates of the inner and outer solvents. This ensures that the sheath layer can uniformly and completely encapsulate the core layer, forming a composite fiber with a clear structure and strong interface.
[0056] In step S3, the spinning parameters include: the propulsion speed of the core spinning solution, the propulsion speed of the sheath spinning solution, the applied voltage, and the distance between the receiving device and the tip of the spinning needle.
[0057] It is worth noting that spinning parameters are key control variables for obtaining core-sheath fibers with regular morphology and stable structure. By adjusting the propulsion speed ratio of the spinning solution to the core layer and the sheath layer, the diameter ratio of the core layer to the sheath layer in the final fiber can be controlled, thereby adjusting the loading and release dynamics of DFO. Voltage and receiving distance jointly affect the stretching effect of the electrostatic field on the spinning jet, determining the diameter and orientation of the fiber. Those skilled in the art can optimize these parameters within the scope given in the claims and embodiments to adapt to different batches of raw materials or environmental conditions, which falls within the scope of conventional process adjustments of this invention.
[0058] In step S4, the photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone or lithium phenyl-2,4,6-trimethylbenzoylphosphinic acid; the alcohol solvent is ethanol, methanol or water;
[0059] It is worth noting that the photoinitiator Irgacure2959 (2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone) is a preferred initiator for GelMA photocrosslinking due to its good water / alcohol solubility and low cytotoxicity. Other types of photoinitiators are listed to show that the crosslinking reaction system does not depend on a specific substance. Any suitable photoinitiator that can initiate the polymerization of methacryloyl groups under ultraviolet light falls within the scope of this invention. Using alcohol solvents to prepare the initiator solution and as a cleaning agent can effectively remove unreacted monomers and initiators, ensuring the biosafety of the final product.
[0060] In step S4, the wavelength of the ultraviolet light is 365 nanometers, and the irradiation time is 20 to 40 minutes;
[0061] It is worth noting that 365 nm ultraviolet light is a commonly used wavelength for exciting the photoinitiator. It has suitable energy and moderate penetration, which can reduce potential damage to the material itself (such as drug activity) while ensuring crosslinking efficiency. The irradiation time of 20 to 40 minutes is an effective and safe range. Within this time, it is sufficient to induce GelMA to fully crosslink and form a stable network. Too short a time may lead to insufficient crosslinking and poor sheath stability; too long a time may lead to material aging or uneconomical energy efficiency. This parameter range ensures the reliability and repeatability of the process.
[0062] Example 1
[0063] A core-sheath structure wound dressing based on coaxial electrospinning, wherein the core material is polycaprolactone (PCL) as structural support, deferoxamine (DFO) as an angiogenic agent, the sheath material is methacryloyl gelatin (GelMA) as a hydrophilic matrix, and silver nanoparticles (AgNPs) as an antibacterial agent.
[0064] The preparation method is as follows:
[0065] Step S1: Preparation of core spinning solution: Accurately weigh 0.4 g of PCL (molecular weight approximately 80,000), dissolve it in 4 mL of hexafluoroisopropanol (HFIP), and magnetically stir at room temperature for 4 hours until completely dissolved to obtain a PCL solution with a mass-volume concentration of 10%. Then, add 6.2 mg of DFO to this clear solution and continue magnetically stirring for 2 hours to ensure that DFO is uniformly dispersed in the PCL solution, thus obtaining a uniform and stable core spinning solution.
[0066] Step S2: Preparation of sheath spinning solution: Accurately weigh 0.84 g of methacrylamide gelatin (GelMA, degree of substitution approximately 60%), dissolve it in 6 mL of trifluoroethanol, and magnetically stir until completely dissolved to obtain a GelMA solution with a mass-volume concentration of 14%. Then, add 9.3 mg of silver nanoparticles with an average particle size of approximately 60 nm to the solution, sonicate for 30 minutes to initially disperse the nanoparticles, and then continue magnetic stirring for 2 hours to obtain a uniformly dispersed sheath spinning solution without obvious aggregation.
[0067] Step S3, Coaxial Electrospinning: Using an electrospinning device equipped with a coaxial spinneret (inner needle 20G, outer needle 18G), the core spinning solution prepared in step S1 is injected into the inner syringe, and the sheath spinning solution prepared in step S2 is injected into the outer syringe. The propulsion speed of the core spinning solution is set to 1.0 ml / h, and the propulsion speed of the sheath spinning solution is set to 1.5 ml / h. The high voltage power supply is turned on and the voltage is adjusted to 8.8 kV. The flat receiver covered with aluminum foil is placed 18 cm away from the tip of the spinneret. Spinning is carried out at room temperature. After electrospinning, the nascent fiber membrane is dried in an oven at 40 degrees Celsius for 1 day.
[0068] Step S4, UV crosslinking treatment: Prepare a 3% (w / v) photoinitiator solution: Dissolve 0.3 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone (Irgacure2959) in 10 mL of anhydrous ethanol and stir magnetically until completely dissolved. Immerse the nascent fiber membrane obtained in step S3 in the photoinitiator solution for 5 minutes to ensure it is fully wetted. After removal, place it under a UV lamp with a wavelength of 365 nm for 30 minutes. After irradiation, transfer the fiber membrane to fresh anhydrous ethanol for soaking and washing twice, 1 hour each time, to thoroughly remove unreacted monomers and residual photoinitiator. Finally, place the fiber membrane in a vacuum drying oven to dry for 1 day to obtain the core-sheath structure wound dressing. Scanning electron microscopy shows that the fiber morphology is good, with an average diameter of about 600 nm.
[0069] Example 2
[0070] A core-sheath structure wound dressing based on coaxial electrospinning, wherein the core material is selected from polycaprolactone (PCL) and deferroamine (DFO), and the sheath material is selected from methacrylamide gelatin (GelMA) and silver nanoparticles (AgNPs).
[0071] The preparation method is as follows:
[0072] S1. Preparation of core spinning solution: Weigh 0.4 g of PCL and dissolve it in 5 mL of hexafluoroisopropanol to prepare a PCL solution with a mass-volume concentration of 8%. Add 5.0 mg of DFO to this solution and stir to disperse evenly, to obtain a core spinning solution with a DFO loading (based on the total mass of the fiber membrane) of 0.5%.
[0073] S2. Preparation of sheath spinning solution: Weigh 0.6 g of GelMA and dissolve it in 5 mL of trifluoroethanol to prepare a GelMA solution with a mass-volume concentration of 12%. Add 5.0 mg of silver nanoparticles (particle size 60 nm), and after ultrasonic and stirring treatment, obtain a uniform sheath spinning solution with an AgNPs loading (based on the total mass of the fiber membrane) of 0.5%.
[0074] S3. Coaxial electrospinning: The above spinning solution is loaded into a coaxial spinning device. To adapt to a lower concentration of spinning solution, the process parameters are adjusted as follows: the core flow rate is set to 0.5 ml / h, the sheath flow rate is set to 1.0 ml / h, the spinning voltage is adjusted to 7.5 kV, and the receiving distance is shortened to 15 cm. Spinning is then carried out, followed by drying in a 40°C oven for 1 day, and the nascent fiber membrane is collected.
[0075] S4. UV Crosslinking Treatment: Same as in Example 1, soaked in 3% Irgacure 2959 ethanol solution, irradiated with 365nm UV light for 30 minutes, then washed and dried in a vacuum drying oven at 40 degrees Celsius for 1 day. The resulting dressing is lighter and thinner with better breathability.
[0076] In summary, Example 1 provides a standardized and reproducible preparation example, verifying the core feasibility of the technical solution; Example 2 shows that, near the lower limit of the active ingredient concentration, a qualified dressing can also be prepared by adapting the process, demonstrating the rationality of the protection range and the robustness of the technical solution.
[0077] All the products obtained in the embodiments possess the core features and advantages expected by the present invention: the PCL core layer provides mechanical support, the GelMA cross-linked mesh provides hydrophilicity and stability, Ag achieves controllable antibacterial properties, and DFO achieves long-term angiogenesis promotion. These embodiments together verify the effectiveness, inventiveness, and feasibility of the combination of the "core-sheath structure design," "materials science combination," and "post-cross-linking fixation process" in systematically solving the problems listed in the background art. Those skilled in the art can combine or adjust the specific parameters in the above embodiments according to actual needs within the scope of the claims of the present invention.
[0078] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0079] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A core-sheath structure wound dressing based on coaxial electrospinning, comprising nanofibers, characterized in that, The nanofiber has a core layer and a sheath layer enclosing the core layer. The core layer contains polycaprolactone and deferoxamine loaded in the polycaprolactone. The sheath layer contains methacrylamide gelatin and silver nanoparticles loaded in the methacrylamide gelatin. The methacrylamide gelatin is cross-linked under ultraviolet light to form a covalent network structure.
2. The core-sheath structure wound dressing based on coaxial electrospinning according to claim 1, characterized in that, The mass-volume concentration of polycaprolactone in the core spinning solution is 8% to 12%, and the loading of deferoxamine (based on the total mass of the fiber membrane) is 0.25% to 0.75%.
3. The core-sheath structure wound dressing based on coaxial electrospinning according to claim 1, characterized in that, The methacrylamide gelatin has a mass-volume concentration of 12% to 16% in the sheath spinning solution, and the loading of silver nanoparticles (based on the total mass of the fiber membrane) is 0.5% to 0.75%.
4. The core-sheath structure wound dressing based on coaxial electrospinning according to claim 1, characterized in that, The silver nanoparticles have a particle size of 60 to 120 nanometers.
5. The core-sheath structure wound dressing based on coaxial electrospinning according to claim 1, characterized in that, The nanofibers have an average diameter of 100 nanometers to 1,000 nanometers.
6. A method for preparing a core-sheath structure wound dressing based on coaxial electrospinning according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Dissolve polycaprolactone in a first organic solvent and stir until completely dissolved to obtain a polycaprolactone solution. Then, add deferoxamine to the polycaprolactone solution and stir until uniformly dispersed to obtain a core spinning solution. S2. Dissolve methacrylamide gelatin in a second organic solvent and stir until completely dissolved to obtain a methacrylamide gelatin solution. Then add silver nanoparticles to the methacrylamide gelatin solution and treat with ultrasound and stirring until uniformly dispersed to obtain a sheath spinning solution. S3. The core spinning solution obtained in S1 and the sheath spinning solution obtained in S2 are injected into the inner and outer injectors of the coaxial electrospinning device, respectively. The spinning parameters are set, and coaxial electrospinning is performed. After electrospinning, the fibers are dried in an oven at 40 degrees Celsius for 1 day. The nascent fiber membrane with a core-sheath structure is collected on the receiving device. S4. Dissolve the photoinitiator in an alcohol solvent to obtain a photoinitiator solution. Immerse the nascent fiber membrane obtained in S3 in the photoinitiator solution and then irradiate it under ultraviolet light to cause the methacrylamide gelatin to undergo a crosslinking reaction. After the crosslinking is completed, wash it with an alcohol solvent and dry it in a vacuum drying oven at 40 degrees Celsius for 1 day to obtain the core-sheath structure wound dressing.
7. The method for preparing a core-sheath structure wound dressing based on coaxial electrospinning according to claim 6, characterized in that, In step S1, the first organic solvent is hexafluoroisopropanol; in step S2, the second organic solvent is trifluoroethanol.
8. The method for preparing a core-sheath structure wound dressing based on coaxial electrospinning according to claim 6, characterized in that, In step S3, the spinning parameters include: the propulsion speed of the core spinning solution, the propulsion speed of the sheath spinning solution, the applied voltage, and the distance between the receiving device and the tip of the spinning needle.
9. The method for preparing a core-sheath structure wound dressing based on coaxial electrospinning according to claim 6, characterized in that, In step S4, the photoinitiator is one of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone or phenyl-2,4,6-trimethylbenzoylphosphinic acid lithium; the alcohol solvent is ethanol, methanol or water.
10. The method for preparing a core-sheath structure wound dressing based on coaxial electrospinning according to claim 6, characterized in that, In step S4, the wavelength of the ultraviolet light is 365 nanometers, and the irradiation time is 20 to 40 minutes.