A porous microsphere-reinforced injectable in-situ forming hydrogel dressing and a preparation method thereof
By combining porous microspheres with a photocrosslinkable hydrogel matrix, a mechanical anchoring structure is formed, which solves the problems of insufficient mechanical strength and rapid degradation of existing hydrogel dressings. It achieves a balance between injectability and mechanical support, and provides continuous healing-promoting activity through a graded sustained-release mechanism, thereby improving the overall performance of hydrogel dressings.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GEHUI MEDICAL TECH (HEILONGJIANG) CO LTD
- Filing Date
- 2026-06-04
- Publication Date
- 2026-08-04
AI Technical Summary
Existing injectable hydrogel dressings suffer from insufficient mechanical strength, rapid degradation, and limited bioactivity, making it difficult to balance the convenience of injectability with the reliability of mechanical support, and they also cannot achieve sustained healing-promoting activity.
An injectable in-situ moldable hydrogel dressing reinforced with porous microspheres forms a mechanical anchoring structure by combining silk fibroin (SF) and chitosan (CS) composite porous microspheres with photocrosslinkable hydrogel matrix components. The honeycomb pore structure achieves mechanical reinforcement, and the microspheres and matrix provide continuous healing-promoting activity through a graded sustained-release mechanism.
It significantly improves the mechanical properties of hydrogels, meeting the long-term support needs of moving parts such as joints, and achieves good injectability and anti-fatigue properties. At the same time, it provides continuous antibacterial and healing-promoting effects through multi-component graded sustained release.
Smart Images
Figure CN122499352A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of injectable hydrogel dressing technology, specifically to a porous microsphere-reinforced injectable in-situ molding hydrogel dressing and its preparation method. Background Technology
[0002] Injectable in-situ molding hydrogels have attracted widespread attention due to their ability to fill irregular wounds and reduce invasive procedures. However, existing injectable hydrogel dressings generally suffer from insufficient mechanical strength, rapid degradation, and limited bioactivity. While dual-network hydrogels constructed from natural polymers such as carboxymethyl chitosan (CMC) and sericin exhibit high swelling rates and rapid hemostasis, their compressive modulus is typically only 10-50 kPa, which is insufficient to meet the mechanical support requirements of wounds in mobile areas such as joints. On the other hand, while silk fibroin (SF) and chitosan (CS) composite nanofiber scaffolds possess good mechanical properties and antibacterial activity, they cannot be injected. The key technological bottleneck lies in balancing the convenience of injectability with the reliability of mechanical support, while simultaneously endowing the hydrogel with sustained healing-promoting activity. Summary of the Invention
[0003] The purpose of this invention is to provide a porous microsphere-reinforced injectable in-situ moldable hydrogel dressing and its preparation method, which takes into account both the convenience of injectability and the reliability of mechanical support, and endows the hydrogel with continuous healing-promoting activity.
[0004] The objective of this invention can be achieved through the following technical solutions: A porous microsphere-reinforced injectable in-situ moldable hydrogel dressing includes a porous microsphere component and a photocrosslinkable hydrogel matrix component. The porous microsphere component is dispersed in the photocrosslinkable hydrogel matrix component as a reinforcing filler. The precursor liquid of the photocrosslinkable hydrogel matrix component penetrates into the pores of the porous microsphere component and forms a mechanical anchoring structure after in-situ photocrosslinking and curing.
[0005] The porous microspheres are composed of silk fibroin SF and chitosan CS composite porous microspheres. The particle size of the porous microspheres is 100-300 μm, the pore size is 2-10 μm, and the porosity is 68%. The interior of the porous microspheres is a honeycomb interconnected porous network. The mass ratio of silk fibroin SF to chitosan CS in the porous microspheres is 5-7:3-5.
[0006] The photocrosslinkable hydrogel matrix component includes methacryloyl gelatin (GelMA) and carboxymethyl cellulose (CMC), with a mass ratio of 6-8:2-4 between methacryloyl gelatin (GelMA) and CMC; the degree of substitution of methacryloyl gelatin (GelMA) is 45%-75%.
[0007] The photocrosslinkable hydrogel matrix component also includes a photoinitiator LAP, which is lithium phenyl-2,4,6-trimethylbenzoylphosphonate, and the mass fraction of the photoinitiator is 0.05%-0.2%.
[0008] It also includes natural antibacterial and healing-promoting ingredients, namely fenugreek oil, with a mass fraction of 3%-8%.
[0009] The porous microsphere component has a mass fraction of 10%-20% in the uncured mixture of the injectable in-situ hydrogel dressing.
[0010] A method for preparing a porous microsphere-reinforced injectable in-situ moldable hydrogel dressing, the method comprising the following steps: Step S1: Prepare porous microsphere components; Step S2: Prepare photocrosslinkable hydrogel matrix components; Step S3: Disperse the porous microsphere component in the photocrosslinkable hydrogel matrix component, add natural antibacterial and healing-promoting ingredients, and form an in-situ shaped hydrogel dressing.
[0011] Step S4: Inject the in-situ molded hydrogel dressing into the designated location, and then irradiate it with blue light to crosslink and cure it, thus obtaining a cured hydrogel.
[0012] Step S1 includes: mixing regenerated silk fibroin solution and chitosan solution in a volume ratio, adding glutaraldehyde as a crosslinking agent, and preparing by emulsification-chemical crosslinking method; dropping the mixed solution into liquid paraffin, stirring to form water-in-oil emulsion, and then centrifuging, washing, and freeze-drying after crosslinking to obtain porous microspheres.
[0013] Step S2 includes: dissolving methacrylamide gelatin (GelMA) in phosphate PBS solution, dissolving carboxymethyl cellulose (CMC) in phosphate PBS solution, mixing the methacrylamide gelatin (GelMA) solution and carboxymethyl cellulose (CMC) solution in a mass ratio, and adding photoinitiator LAP to obtain a photocrosslinkable hydrogel matrix.
[0014] The wavelength of the blue light irradiation is 405nm, and the irradiation time is 30-90 seconds.
[0015] The beneficial effects of this invention are: Through the honeycomb-like pore structure on the surface and inside of the porous microspheres, the precursor liquid of the photocrosslinkable hydrogel matrix can fully penetrate into the pores of the microspheres. After in-situ photocrosslinking and curing, a strong mechanical anchoring structure is formed, fundamentally solving the problem of weak interfacial bonding between traditional solid microspheres and the hydrogel matrix. This results in a significant improvement in the mechanical properties of the porous microspheres through their mechanical interlocking mechanism. The compressive modulus can reach 150-300 kPa, which can meet the long-term mechanical support requirements of wounds in moving parts such as joints.
[0016] The interlocking structure formed by porous microspheres and the hydrogel matrix not only enhances static mechanical strength but also significantly improves dynamic fatigue resistance. After 10 cycles of strain compression, the modulus retention rate of the hydrogel of this invention reaches 89%-91%, while that of the smooth microsphere-reinforced group is only 72%. With a microsphere addition of 15%, the cyclic modulus retention rate reaches 91%, exhibiting the best fatigue resistance. This characteristic is particularly important for wounds in frequently moving areas such as the knee and elbow joints, ensuring that the dressing maintains structural integrity and functional stability under repeated stress, adapting to the dynamic wound environment.
[0017] By optimizing the microsphere size and dosage, this invention controls the viscosity of the mixed solution within the range of 100-500 mPas. After injection, in-situ cross-linking and curing can be achieved by irradiation with 405 nm blue light for 30-90 seconds. The shape retention rate after curing is 95%, which can perfectly fill wounds of various irregular shapes. Compared with traditional microsphere-reinforced hydrogels, this invention achieves mechanical enhancement while maintaining good injectability, truly realizing enhanced mechanical properties while ensuring operability.
[0018] Porous microspheres serve as secondary drug loading carriers, enabling graded sustained release of multiple components. The porous surface structure and internal honeycomb-like interconnected porous network of the microspheres not only provide a structural basis for the permeation and anchoring of the hydrogel matrix but also serve as independent drug loading carriers, pre-loaded with growth factors or therapeutic drugs. This dual-carrier system of microsphere-loaded drugs and matrix-loaded drugs allows for graded sustained release of different active ingredients: components such as fenugreek oil in the hydrogel matrix are rapidly released in the early stages to exert antibacterial effects, while growth factors such as bFGF and VEGF loaded within the microspheres are slowly released as the microspheres degrade, continuously promoting angiogenesis and tissue regeneration.
[0019] All materials used in this invention are natural biodegradable polymers. Silk fibroin, chitosan, gelatin, and carboxymethyl cellulose all possess excellent biocompatibility. The high specific surface area of the porous microspheres can effectively load natural antibacterial and healing-promoting components such as fenugreek oil, achieving slow release.
[0020] The degradation rate of the hydrogel can be flexibly controlled by adjusting the amount of porous microspheres added. A 10% addition rate results in complete degradation in approximately 21 days, a 15% addition rate in approximately 28 days, and a 20% addition rate in approximately 35 days. This characteristic allows the present invention to select the appropriate microsphere addition amount based on the healing cycle of different wounds: a 10% addition rate can be selected for superficial wounds, with degradation in approximately 21 days; while a 15%-20% addition rate can be selected for deep wounds or wounds near joints, with degradation in approximately 28-35 days. This ensures the dressing continues to function during wound healing and avoids premature degradation and failure. The degradation rate is controllable and adaptable to different wound healing cycles.
[0021] The invention will now be further described with reference to the accompanying drawings.
[0022] Figure 1 This is a schematic diagram of the preparation method of the porous microsphere-reinforced injectable in-situ molded hydrogel dressing of the present invention; Figure 2 This is a schematic diagram of the mechanical anchoring structure formed by the porous microspheres and hydrogel matrix of the present invention. Detailed Implementation
[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] A porous microsphere-reinforced injectable in-situ molded hydrogel dressing includes a porous microsphere component and a photocrosslinkable hydrogel matrix component. The porous microsphere component is dispersed in the photocrosslinkable hydrogel matrix component as a reinforcing filler. The photocrosslinkable hydrogel matrix component penetrates into the pores of the porous microsphere component to form an in-situ molded hydrogel dressing. After in-situ photocrosslinking and curing, it forms a mechanical anchoring structure.
[0025] The porous microspheres are composed of silk fibroin (SF) and chitosan (CS) composite porous microspheres. The particle size of the porous microspheres is 100-300 μm, the pore size is 2-10 μm, the porosity is 68%, and the interior of the porous microspheres is a honeycomb interconnected porous network.
[0026] Through the honeycomb-like pore structure on the surface and inside of the porous microspheres, the precursor liquid of the photocrosslinkable hydrogel matrix can fully penetrate into the pores of the microspheres. After in-situ photocrosslinking and curing, a strong mechanical anchoring structure is formed, fundamentally solving the problem of weak interfacial bonding between traditional solid microspheres and the hydrogel matrix. This results in a significant improvement in the mechanical properties of the porous microspheres through their mechanical interlocking mechanism. The compressive modulus can reach 150-300 kPa, which meets the long-term mechanical support requirements of wounds in moving parts such as joints. It also avoids the interfacial delamination problem that easily occurs in traditional smooth microsphere reinforcement systems.
[0027] The porous surface structure and internal honeycomb-like interconnected porous network of porous microspheres not only provide a structural basis for the permeation and anchoring of the hydrogel matrix, but also serve as independent drug loading carriers, pre-loaded with growth factors or therapeutic drugs. This dual-carrier system of microsphere drug loading + matrix drug loading enables the graded sustained release of different active ingredients: components such as fenugreek oil in the hydrogel matrix are rapidly released in the early stage to exert antibacterial effects, while growth factors such as bFGF and VEGF loaded in the microspheres are slowly released as the microspheres degrade, continuously exerting angiogenesis and tissue regeneration-promoting effects.
[0028] The silk fibroin SF is a natural high-molecular-weight fibrous protein extracted from silkworm silk, possessing excellent biocompatibility, biodegradability, and mechanical properties. The chitosan CS is a natural polysaccharide extracted from the shells of crustaceans, exhibiting good biocompatibility, antibacterial properties, and adhesive properties. The particle size refers to the diameter of the microspheres; a particle size range of 100-300 μm ensures that the microspheres can pass smoothly through the syringe needle, guaranteeing injectability, while also having sufficient internal space to accommodate the hydrogel matrix and form an anchoring structure. The pore size refers to the diameter of the internal channels of the microspheres; a pore size range of 2-10 μm ensures that the hydrogel matrix solution can smoothly penetrate into the pores, while simultaneously forming sufficient mechanical anchoring force. The porosity refers to the percentage of pore volume in the total volume of the microspheres; a porosity of not less than 68% ensures sufficient space to accommodate the hydrogel matrix and form a adequate mechanical anchoring structure.
[0029] By combining silk fibroin and chitosan, the advantages of both are combined, ensuring the mechanical properties of the microspheres while endowing them with good biocompatibility and antibacterial properties. By optimizing the particle size, pore size and porosity parameters of the microspheres, the best balance between injectability and mechanical enhancement effect is achieved.
[0030] The mass ratio of silk fibroin (SF) to chitosan (CS) in the porous microspheres is 5-7:3-5. The mass fraction of the porous microsphere component in the injectable in-situ hydrogel dressing is 10%-20%.
[0031] The mass ratio refers to the ratio of silk fibroin (SF) to chitosan (CS) in porous microspheres. When the proportion of silk fibroin (SF) is too high, the porous microspheres become more brittle and prone to breakage during preparation and use; when the proportion of chitosan (CS) is too high, the porous microspheres exhibit excessive swelling, affecting their mechanical stability. A mass ratio range of 5-7:3-5 balances the mechanical strength, biocompatibility, and structural stability of the microspheres. By optimizing the ratio of silk fibroin (SF) to chitosan (CS), composite porous microspheres with optimal overall performance were obtained, providing an ideal reinforcing phase for hydrogel dressings.
[0032] The photocrosslinkable hydrogel matrix component includes methacrylamide gelatin (GelMA) and carboxymethyl cellulose (CMC), with a mass ratio of methacrylamide gelatin (GelMA) to carboxymethyl cellulose (CMC) of 6-8:2-4; and a degree of substitution of methacrylamide gelatin (GelMA) of 45%-75%.
[0033] The photocrosslinked gelatin derivative used in this embodiment is methacrylamide gelatin, which is a photosensitive polymer material obtained by modifying gelatin molecules with methacrylamide groups and is prepared by reacting methacrylic anhydride with gelatin; the carboxymethyl cellulose (CMC) is a natural cellulose derivative with good water solubility, biocompatibility and thickening effect.
[0034] The mass ratio refers to the mass ratio of methacrylamide gelatin (GelMA) to carboxymethyl cellulose (CMC) in the matrix. When the proportion of methacrylamide gelatin (GelMA) is too high, the hydrogel becomes brittle and lacks toughness; when the proportion of carboxymethyl cellulose (CMC) is too high, the crosslinking density of the hydrogel decreases, and its mechanical properties decline. A mass ratio range of 6-8:2-4 balances the mechanical properties, toughness, and injectability of the hydrogel. By combining methacrylamide gelatin (GelMA) with carboxymethyl cellulose (CMC), the excellent photocrosslinking properties of methacrylamide gelatin (GelMA) and the superior thickening effect of carboxymethyl cellulose (CMC) are combined, resulting in a hydrogel matrix with good injectability and excellent mechanical properties.
[0035] The degree of substitution refers to the percentage of amino groups modified with methacrylic anhydride in the gelatin molecule. If the substitution is too low, the crosslinking activity of methacryloyl gelatin (GelMA) is insufficient, making it difficult to form a hydrogel of sufficient strength. If the substitution is too high, the biocompatibility of methacryloyl gelatin (GelMA) decreases, and the crosslinking rate is too fast, which is detrimental to operational control. A substitution range of 45%-75% balances crosslinking efficiency and biocompatibility. By optimizing the substitution degree of methacryloyl gelatin (GelMA), an optimal balance between photocrosslinking rate and hydrogel mechanical properties is achieved.
[0036] The photocrosslinkable hydrogel matrix component also includes a photoinitiator LAP, which is lithium phenyl-2,4,6-trimethylbenzoylphosphonate, with a mass fraction of 0.05%-0.2%. After injection, in-situ crosslinking and curing can be completed by irradiation with 405nm blue light for 30-90 seconds, which can perfectly fill wounds of various irregular shapes.
[0037] The LAP is a highly efficient visible light initiator that can efficiently generate free radicals under 405nm blue light irradiation, initiating the cross-linking reaction of methacrylamide gelatin (GelMA). It has the advantages of low cytotoxicity and high initiation efficiency. The mass fraction refers to the percentage of LAP by mass in the matrix solution. Too low a LAP concentration results in insufficient initiation efficiency and incomplete cross-linking; too high a concentration may cause cytotoxicity and increase costs. Using a mass fraction range of 0.05%-0.2% ensures efficient cross-linking while maintaining good biocompatibility. By using LAP as a photoinitiator, rapid cross-linking under visible light is achieved, avoiding the cell damage problems that may arise from UV light initiation.
[0038] It also includes natural antibacterial and healing-promoting ingredients, namely fenugreek oil, which mainly contains trigonelline and 4-hydroxyisoleucine. The mass fraction of fenugreek oil is 3%-8%. The high specific surface area of the porous microspheres can effectively load fenugreek oil and other natural antibacterial and healing-promoting ingredients, achieving slow release. It also has good antibacterial properties, with an antibacterial rate of 78%-96% against Staphylococcus aureus.
[0039] Fenugreek oil is a natural plant oil extracted from fenugreek seeds, possessing various biological activities such as anti-inflammatory, antibacterial, and wound-healing promotion. The mass fraction refers to the percentage of fenugreek oil in the hydrogel dressing. Too low a fenugreek oil content results in insignificant therapeutic effects; too high a content may affect the cross-linking properties and mechanical strength of the hydrogel. A mass fraction range of 3%-8% ensures therapeutic efficacy without compromising the hydrogel's basic properties. By loading fenugreek oil, the hydrogel dressing acquires anti-inflammatory, antibacterial, and wound-healing biological functions, achieving an organic combination of mechanical enhancement and biological therapy.
[0040] The porous microsphere component has a compressive modulus of 150-300 kPa, and its modulus retention rate is not less than 89% after 10 cycles of compression. The interlocking structure formed by the porous microspheres and the hydrogel matrix not only improves static mechanical strength but also significantly enhances dynamic fatigue resistance. After 10 cycles of strain compression, the modulus retention rate of the hydrogel of this invention can reach 89%-91%, while that of the smooth microsphere-reinforced group is only 72%. With a microsphere addition of 15%, the cyclic modulus retention rate reaches 91%, exhibiting the best fatigue resistance. This characteristic is particularly important for wounds in frequently used areas such as the knee and elbow joints, ensuring that the dressing maintains structural integrity and functional stability under repeated stress. It exhibits excellent fatigue resistance and is adaptable to dynamic wound environments.
[0041] To further illustrate the technical solution and beneficial effects of the present invention, detailed descriptions are provided below through specific embodiments.
[0042] Example 1 Step S1: Preparation of SF-CS composite porous microspheres: A 5% (w / v) regenerated silk fibroin solution and a 2% (w / v) chitosan solution (dissolved in 1% acetic acid) were mixed at a volume ratio of 5:5. 0.3% glutaraldehyde was added as a crosslinking agent, and the mixture was prepared using an emulsification-chemical crosslinking method. The mixed solution was dropped into liquid paraffin containing 3% Span 80, stirred at 800 rpm for 30 min to form a water-in-oil emulsion. After crosslinking for 2 h, the mixture was centrifuged, washed, and freeze-dried to obtain porous microspheres with a particle size of 100-200 μm. Both the surface and interior of the microspheres exhibited an interconnected porous structure with a pore size of 2-10 μm and a porosity of 68%.
[0043] The porosity of porous microspheres can be controlled by adjusting the freeze-drying process parameters. Preferably, a porosity of 75% is achieved to obtain better mechanical reinforcement.
[0044] Step S2: Preparation of photocrosslinkable hydrogel matrix: Dissolve GelMA with a substitution degree of about 45% in PBS buffer to prepare a 10% (w / v) solution, dissolve CMC in PBS to prepare a 3% (w / v) solution, mix them at a mass ratio of GelMA:CMC=8:2, and add 0.05% photoinitiator LAP.
[0045] Step S3: Composite hydrogel molding and microsphere interlocking effect: Disperse SF-CS microspheres at a ratio of 10% (w / v) in the above matrix solution, and add 3% fenugreek oil (by volume of the matrix) as a natural antibacterial and healing agent. After mixing evenly, pour the mixture into a double-tube syringe and store it away from light. When using, inject it into the designated location or mold and then irradiate it with 405nm blue light for 90 seconds to solidify in situ.
[0046] Compression modulus 152 kPa; fenugreek oil release rate 35% after 24 hours; Staphylococcus aureus antibacterial rate 78%; L929 cell viability 92%.
[0047] Example 2 Step S1: Preparation of SF-CS composite porous microspheres: A 5% (w / v) regenerated silk fibroin solution and a 2% (w / v) chitosan solution (dissolved in 1% acetic acid) were mixed at a volume ratio of 7:3. 0.6% glutaraldehyde was added as a crosslinking agent, and the mixture was prepared using an emulsification-chemical crosslinking method. The mixed solution was dropped into liquid paraffin containing 3% Span 80, stirred at 800 rpm for 30 min to form a water-in-oil emulsion. After crosslinking for 2 h, the mixture was centrifuged, washed, and freeze-dried to obtain porous microspheres with a particle size of 200-300 μm. Both the surface and interior of the microspheres exhibited an interconnected porous structure with a pore size of 2-10 μm and a porosity of 82%.
[0048] Step S2: Preparation of photocrosslinkable hydrogel matrix: Dissolve GelMA with a substitution degree of about 75% in PBS buffer to prepare a 10% (w / v) solution, dissolve CMC in PBS to prepare a 3% (w / v) solution, mix them at a mass ratio of GelMA:CMC=6:4, and add 0.2% photoinitiator LAP.
[0049] Step S3: Composite hydrogel molding and microsphere interlocking effect: SF-CS microspheres are dispersed in the above matrix solution at a ratio of 20% (w / v), and 8% fenugreek oil (by volume of the matrix) is added as a natural antibacterial and healing agent. After thorough mixing, the mixture is poured into a double-tube syringe and stored away from light. When using, it is injected into the designated location or mold and then cured in situ by irradiation with 405nm blue light for 50 seconds.
[0050] Compression modulus 245 kPa; fenugreek oil release rate 58% after 24 hours; Staphylococcus aureus antibacterial rate 96%; L929 cell viability 88%.
[0051] Example 3 Step S1: Preparation of SF-CS composite porous microspheres: A 5% (w / v) regenerated silk fibroin solution and a 2% (w / v) chitosan solution (dissolved in 1% acetic acid) were mixed at a volume ratio of 6:4. 0.5% glutaraldehyde was added as a crosslinking agent, and the mixture was prepared using an emulsification-chemical crosslinking method. The mixed solution was dropped into liquid paraffin containing 3% Span 80, stirred at 800 rpm for 30 min to form a water-in-oil emulsion. After crosslinking for 2 h, the mixture was centrifuged, washed, and freeze-dried to obtain porous microspheres with a particle size of 150-250 μm. Both the surface and interior of the microspheres exhibited an interconnected porous structure with a pore size of 2-10 μm and a porosity of 75%.
[0052] Step S2: Preparation of photocrosslinkable hydrogel matrix: Dissolve GelMA (substitution degree of about 60%) in PBS buffer to prepare a 10% (w / v) solution, dissolve CMC in PBS to prepare a 3% (w / v) solution, mix them at a mass ratio of GelMA:CMC=7:3, and add 0.1% photoinitiator LAP.
[0053] Step S3: Composite hydrogel molding and microsphere interlocking effect: SF-CS microspheres are dispersed in the above matrix solution at a ratio of 15% (w / v), and 5% fenugreek oil (by volume of the matrix) is added as a natural antibacterial and healing agent. After thorough mixing, the mixture is poured into a double-tube syringe and stored away from light. When using, it is injected into the designated location or mold and then cured in situ by irradiation with 405nm blue light for 70s.
[0054] Compression modulus 186 kPa; fenugreek oil release rate 46% after 24 hours; antibacterial rate against Staphylococcus aureus 87%; L929 cell viability 90%.
[0055] The porous structure of SF-CS microspheres allows low-viscosity matrix solutions to penetrate into the pores on the surface of the microspheres. After solidification, the microspheres form an interlocking mechanical anchoring effect, which significantly improves the overall mechanical properties. At the same time, the chitosan in the microspheres provides continuous antibacterial activity.
[0056] Comparative experiment: Preparation of control samples: Smooth SF microspheres were prepared by conventional silk fibroin emulsion crosslinking method without the addition of pore-forming agents, resulting in pure silk fibroin microspheres with smooth surfaces and no pores, and the particle size was controlled at 150-250 μm.
[0057] The third and fourth sample groups were prepared according to the methods of Examples 3 and 2, and their mechanical properties were compared. Sample group Compression modulus (kPa) Compressive strength (kPa) Modulus retention rate after 10 cycles Pure GelMA / CMC hydrogel 325 8512 61% +15% smooth SF microspheres 7811 15620 72% +15% porous SF-CS microspheres 18624 31235 91% +20% porous SF-CS microspheres 24530 38542 89% After adding smooth SF microspheres, the compressive modulus of the hydrogel increased from 32 kPa to 78 kPa, an increase of about 1.4 times, indicating that the smooth microspheres have a certain mechanical enhancement effect.
[0058] After adding porous SF-CS microspheres, the compressive modulus of the hydrogel increased significantly to 186 kPa, which is 5.8 times that of the pure gel and 2.4 times that of the smooth microsphere-reinforced group, fully demonstrating the excellent mechanical reinforcement effect of the porous microsphere interlocking mechanism.
[0059] In terms of modulus retention, the pure gel had a modulus retention of only 61%, the smooth microsphere reinforced group had a retention of 72%, while the porous microsphere reinforced group had a retention of as high as 91%, indicating that the interlocking mechanism of porous microspheres significantly improved the fatigue resistance of the material.
[0060] When the amount of microspheres added was increased from 15% to 20%, the compressive modulus further increased from 186 kPa to 245 kPa, indicating that the mechanical properties of the hydrogel can be optimized by adjusting the amount of microspheres added.
[0061] After 10 cycles of compression, the modulus retention rate of the porous microsphere-reinforced hydrogel was as high as 91%, which is much higher than the 72% of the smooth microsphere-reinforced group and the 61% of the pure gel. This indicates that the porous microsphere interlocking mechanism of the present invention can significantly improve the fatigue resistance and stability of the hydrogel.
[0062] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.
Claims
1. A porous microsphere-reinforced injectable in-situ moldable hydrogel dressing, comprising a porous microsphere component and a photocrosslinkable hydrogel matrix component, characterized in that: The porous microsphere component is dispersed in the photocrosslinkable hydrogel matrix component as a reinforcing filler. The precursor liquid of the photocrosslinkable hydrogel matrix component penetrates into the pores of the porous microsphere component and forms a mechanical anchoring structure after in-situ photocrosslinking and curing.
2. The porous microsphere-reinforced injectable in-situ moldable hydrogel dressing according to claim 1, characterized in that: The porous microspheres are composed of silk fibroin SF and chitosan CS composite porous microspheres. The particle size of the porous microspheres is 100-300 μm, the pore size is 2-10 μm, and the porosity is 68%. The interior of the porous microspheres is a honeycomb interconnected porous network. The mass ratio of silk fibroin SF to chitosan CS in the porous microspheres is 5-7:3-5.
3. The porous microsphere-reinforced injectable in-situ hydrogel dressing according to claim 1, characterized in that: The photocrosslinkable hydrogel matrix component includes methacrylamide gelatin (GelMA) and carboxymethyl cellulose (CMC), with a mass ratio of methacrylamide gelatin (GelMA) to carboxymethyl cellulose (CMC) of 6-8:2-4; and a degree of substitution of methacrylamide gelatin (GelMA) of 45%-75%.
4. The porous microsphere-reinforced injectable in-situ hydrogel dressing according to claim 1, characterized in that: The photocrosslinkable hydrogel matrix component also includes a photoinitiator LAP, which is lithium phenyl-2,4,6-trimethylbenzoylphosphonate, and the mass fraction of the photoinitiator is 0.05%-0.2%.
5. The porous microsphere-reinforced injectable in-situ moldable hydrogel dressing according to claim 1, characterized in that: It also includes natural antibacterial and healing-promoting ingredients, namely fenugreek oil, with a mass fraction of 3%-8%.
6. The porous microsphere-reinforced injectable in-situ hydrogel dressing according to claim 2, characterized in that: The porous microsphere component has a mass fraction of 10%-20% in the uncured mixture of the injectable in-situ hydrogel dressing.
7. A method for preparing a porous microsphere-reinforced injectable in-situ moldable hydrogel dressing, characterized in that: The method includes the following steps: Step S1: Prepare porous microsphere components; Step S2: Prepare photocrosslinkable hydrogel matrix components; Step S3: Disperse the porous microsphere component in the photocrosslinkable hydrogel matrix component, add natural antibacterial and healing-promoting ingredients, and form an in-situ shaped hydrogel dressing; Step S4: Inject the in-situ molded hydrogel dressing into the designated location, and then irradiate it with blue light to crosslink and cure it, thus obtaining a cured hydrogel.
8. The method for preparing porous microsphere-reinforced injectable in-situ moldable hydrogel dressing according to claim 7, characterized in that: Step S1 includes: mixing regenerated silk fibroin solution and chitosan solution in a volume ratio, adding glutaraldehyde as a crosslinking agent, and preparing by emulsification-chemical crosslinking method; dropping the mixed solution into liquid paraffin, stirring to form water-in-oil emulsion, and then centrifuging, washing, and freeze-drying after crosslinking to obtain porous microspheres.
9. The method for preparing porous microsphere-reinforced injectable in-situ moldable hydrogel dressing according to claim 7, characterized in that: Step S2 includes: dissolving methacrylamide gelatin (GelMA) in phosphate PBS solution, dissolving carboxymethyl cellulose (CMC) in phosphate PBS solution, mixing the methacrylamide gelatin (GelMA) solution and carboxymethyl cellulose (CMC) solution in a mass ratio, and adding photoinitiator LAP to obtain a photocrosslinkable hydrogel matrix.
10. The method for preparing a porous microsphere-reinforced injectable in-situ moldable hydrogel dressing according to claim 7, characterized in that: The wavelength of the blue light irradiation is 405nm, and the irradiation time is 30-90 seconds.