A polyurea fiber membrane, a mechanically active dressing and a preparation method thereof

Abstract

The application relates to the technical field of medical dressings, in particular to a polyurea fiber membrane, a mechanically active dressing and a preparation method thereof. The preparation method of the polyurea fiber membrane comprises the following steps: S1, adding a polyether amine solution into a diisocyanate solution, uniformly stirring at room temperature, and forming a prepolymer solution; S2, adding a diamine monomer solution into the prepolymer solution, then reacting under the condition of 20-50 DEG C, after the reaction is completed, forming the reaction liquid, and obtaining a polyurea elastomer; wherein the side chain of the diamine monomer contains a hydrophilic group; S3, dissolving the polyurea elastomer in an organic solvent to obtain an electrospinning solution; and S4, electrospinning the electrospinning solution to obtain the polyurea fiber membrane. The polyurea fiber membrane obtained by electrospinning the polyurea elastomer has sufficient strength and toughness; and the polyurea fiber membrane can generate a shrinkage force under the action of water, so as to promote wound closure.

Description

Technical Field

[0001] This invention relates to the field of medical dressing technology, and more specifically, to a polyurea fiber membrane, a mechanically active dressing, and a method for preparing the same. Background Technology

[0002] Wound management is a central issue in clinical nursing, and dressings are commonly used for wound treatment. Current dressings mainly consist of gauze and cotton wool, primarily aimed at maintaining moisture at the wound site, managing exudate, and protecting the wound from pathogenic infection by delivering antimicrobial agents. While these strategies are widely used, they are unreliable for treating large-area injuries and chronic wounds because they rely on a slow and passive healing process. To further promote wound healing, much work has focused on delivering bioactive substances, such as growth factors and cells derived from the dressing. Recently, sophisticated wound dressings have been developed to monitor and respond to physiological signals at the wound site, including local bacterial strain, temperature, and pH. However, these designs often require complex manufacturing processes, are costly, involve drug side effects, and present difficulties in loading and controlling the release of bioactive agents.

[0003] Embryonic wound healing, which provides perfect regeneration of fetal skin, can inspire new strategies for wound dressing design. Embryonic wound healing involves the formation of actin cords at the leading edge of the cells surrounding the wound. These actin cords contract and exert force, pulling the wound edges together in a purse-like manner. Inspired by the contractile capacity of embryonic wounds, a new type of wound dressing, called a mechanoactive adhesive dressing, has been developed to apply sufficient contractile force to promote active wound closure. In this design, the mechanoactive adhesive dressing needs to be biomechanically active, requiring it to possess the following properties: sufficient strength and toughness; the ability to generate contractile force in response to external stimuli after being placed on the skin; and strong adhesion to effectively transfer these contractile forces to the wound edges. However, preparing a mechanoactive dressing that simultaneously meets all these properties remains challenging. Summary of the Invention

[0004] The technical problem solved by this invention is: how to prepare a mechanically active adhesive dressing with the following characteristics: sufficient strength and toughness; able to generate contractile force in response to external stimuli after being placed on the skin, and having strong adhesion.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a polyurea fiber membrane, comprising:

[0007] Step S1: Add the polyetheramine solution to the diisocyanate solution and stir evenly at room temperature to form a prepolymer solution;

[0008] Step S2: Add a diamine monomer solution to the prepolymer solution, and then react it at a temperature of 20-50°C. After the reaction is completed, allow the reaction solution to solidify to obtain a polyurea elastomer; wherein the side chain of the diamine monomer contains hydrophilic groups.

[0009] Step S3: Dissolve the polyurea elastomer in an organic solvent to obtain an electrospinning solution;

[0010] Step S4: Electrospinning is performed using the electrospinning solution to obtain a polyurea fiber membrane.

[0011] Compared with existing technologies, this invention uses polyetheramine, diisocyanate, and diamine monomers as reactants. The amino groups in the polyetheramine react with the isocyanate groups in the diisocyanate to form urea groups that constitute double hydrogen bonds. The isocyanate groups in the diisocyanate react with the diamino groups in the diamine monomer to form quadruple hydrogen bonds, forming a non-covalently cross-linked, spider-silk-like polyurea molecular structure. Because the molecular chain structure contains reversible strong hydrogen bonds (quadruple hydrogen bonds) and weak hydrogen bonds (double hydrogen bonds), adjusting the ratio of strong and weak hydrogen bonds allows the prepared polyurea to have a wide range of adjustable strength and toughness. The cross-linking of hydrogen bonds increases the interaction forces between polyurea molecular chains, strengthens the cross-linked network structure, and improves the material's strength. Under external force, the reversible hydrogen bond cross-linking dissipates some energy, improving the material's toughness. This mechanism enables the prepared polyurea elastomer to possess both strong and tough mechanical properties, solving the problem of the incompatibility between strength and toughness in elastomers. Furthermore, reversible hydrogen bonds can act as molecular switches; applying external force can alter the network structure and macroscopic shape. Once the reversible bonds are rebuilt, the network structure is fixed, forming a temporary shape. When the reversible bonds are broken again, the network structure changes in the direction of increasing entropy under entropy-driven conditions, and the temporary shape returns to its initial shape, completing a shape memory cycle. Therefore, the polyurea elastomer prepared by this invention possesses strong and tough mechanical properties and excellent shape memory properties. In addition, because the side chains of the diamine monomer contain hydrophilic groups, the polyurea elastomer exhibits humidity-responsive characteristics. Consequently, the polyurea fiber membrane obtained by electrospinning the polyurea elastomer prepared by this invention has sufficient strength and toughness. This polyurea fiber membrane can generate contractile force under the action of water, thereby promoting wound closure. Experiments have shown that when this polyurea fiber membrane is wrapped around a fresh wound, it can tightly adhere to the wound, exhibiting strong adhesion properties, thus meeting the dynamic changes of complex wounds and effectively converting contractile force for wound closure.

[0012] Preferably, the diamine monomer includes at least one selected from 1,3-diamino-2-propanol, 2,6-diamino-3-pyridinol, and 2-(4,6-diamino-1,3,5-triazin-2-yl)ethanol.

[0013] Preferably, the polyetheramine includes at least one of polyetheramine 2000, polyetheramine 300, and polyetheramine 230; the diisocyanate includes at least one of isophorone diisocyanate, 1,6-hexane diisocyanate, and 4,4-dicyclohexane diisocyanate.

[0014] Preferably, the molar ratio of the diisocyanate, the polyetheramine, and the diamine monomer is 10:3.4632-7.4074:2.1164-6.0606.

[0015] Preferably, the electrospinning solution has a mass fraction of 25%.

[0016] Preferably, in step S4, the electrospinning advance speed is 0.5 ml / h, the voltage is 15 kV, and the distance between the syringe and the collector is 30 cm.

[0017] The present invention also provides a polyurea fiber membrane, which is prepared by the polyurea fiber membrane preparation method described above.

[0018] This invention also provides a method for preparing a mechanically active dressing, comprising:

[0019] Step M1: Immerse the polyurea fiber membrane as described above in a dopamine solution, adjust the pH value to 8.5, react at room temperature for 22-26 hours, then wash and dry to obtain a composite fiber membrane;

[0020] Step M2: Immerse the composite fiber membrane in silver ammonia solution, add glucose solution, stir and react for 10-14 hours, then wash and dry to obtain mechanically active dressing.

[0021] Preferably, in step M1, the concentration of the dopamine solution is 2 mg / ml.

[0022] The present invention also provides a mechanically active dressing, which is prepared by the mechanically active dressing preparation method described above.

[0023] Compared with existing technologies, the polyurea fiber membrane prepared by this invention possesses sufficient strength and toughness. This polyurea fiber membrane can generate contractile force under the action of water, thereby promoting wound closure. Experiments have shown that when this polyurea fiber membrane is wrapped around a fresh wound, it can tightly adhere to the wound, exhibiting strong adhesive properties, thus meeting the dynamic changes of complex wounds and effectively converting contractile force for wound closure. This invention further composites dopamine and Ag nanoparticles onto the polyurea fiber membrane to obtain a mechanically active dressing. Because dopamine has a strong effect on Ag... +With strong adsorption capacity, Ag nanoparticles can uniformly coat the outer wall of the polyurea fiber membrane, allowing them to directly contact bacteria and thus providing a good antibacterial effect. Furthermore, the mechanically active dressing provided by this invention integrates different compositions and functional zones, achieving both excellent antibacterial properties and sufficient strength and toughness. When this mechanically active dressing is applied to a fresh wound, water stimulation causes the dressing to absorb water and shrink, thereby promoting wound closure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the process for preparing polyurea fiber membrane in an embodiment of the present invention;

[0025] Figure 2 This is a photograph of the polyurea fiber membrane prepared in Example 1;

[0026] Figure 3 Here is a scanning electron microscope image of the polyurea fiber membrane prepared in Example 1;

[0027] Figure 4 A photograph of a fresh wound wrapped with the polyurea fiber membrane prepared in Example 1;

[0028] Figure 5 The process diagram shows the polyurea fiber membrane being immersed in water for 2 seconds and then removed, followed by biaxial stretching of the moistened polyurea fiber membrane.

[0029] Figure 6 Here is a scanning electron microscope image of the mechanically active dressing prepared in Example 1;

[0030] Figure 7 This is a diagram illustrating the process by which the mechanically active dressing prepared in Example 1 promotes wound closure.

[0031] Figure 8 This is a diagram illustrating the process of non-invasively wrapping the heart with the mechanically active dressing prepared in Example 1. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] It should be noted that, unless otherwise specified, the features in the embodiments of this invention can be combined with each other. The terms "comprising," "including," "containing," and "having" are non-limiting, meaning that other steps and other components that do not affect the results can be added. The above terms cover the terms "composed of" and "substantially composed of." Unless otherwise specified, the materials, equipment, and reagents are commercially available.

[0034] like Figure 1 As shown, this embodiment of the invention provides a method for preparing a polyurea fiber membrane, comprising:

[0035] Step S1: Add the polyetheramine solution to the diisocyanate solution and stir evenly at room temperature to form a prepolymer solution;

[0036] Step S2: Add a diamine monomer solution to the prepolymer solution, and then react it at a temperature of 20-50°C. After the reaction is completed, allow the reaction solution to solidify to obtain a polyurea elastomer; wherein the side chain of the diamine monomer contains hydrophilic groups.

[0037] Step S3: Dissolve the polyurea elastomer in an organic solvent to obtain an electrospinning solution;

[0038] Step S4: Electrospinning is performed using the electrospinning solution to obtain a polyurea fiber membrane.

[0039] Compared with existing technologies, this invention uses polyetheramine, diisocyanate, and diamine monomers as reactants. The amino groups in the polyetheramine react with the isocyanate groups in the diisocyanate to form urea groups that constitute double hydrogen bonds. The isocyanate groups in the diisocyanate react with the diamino groups in the diamine monomer to form quadruple hydrogen bonds, forming a non-covalently cross-linked, spider-silk-like polyurea molecular structure. Because the molecular chain structure contains reversible strong hydrogen bonds (quadruple hydrogen bonds) and weak hydrogen bonds (double hydrogen bonds), adjusting the ratio of strong and weak hydrogen bonds allows the prepared polyurea to have a wide range of adjustable strength and toughness. The cross-linking of hydrogen bonds increases the interaction forces between polyurea molecular chains, strengthens the cross-linked network structure, and improves the material's strength. Under external force, the reversible hydrogen bond cross-linking dissipates some energy, improving the material's toughness. This mechanism enables the prepared polyurea elastomer to possess both strong and tough mechanical properties, solving the problem of the incompatibility between elastomer strength and toughness. Furthermore, reversible hydrogen bonds can act as molecular switches; applying external force can alter the network structure and macroscopic shape. Once the reversible bonds are rebuilt, the network structure is fixed, forming a temporary shape. When the reversible bonds are broken again, the network structure changes in the direction of increasing entropy under entropy-driven conditions, and the temporary shape returns to its initial shape, completing a shape memory cycle. Therefore, the polyurea elastomer prepared in this invention possesses strong and tough mechanical properties and excellent shape memory properties. Additionally, because the side chains of the diamine monomer contain hydrophilic groups, the polyurea elastomer exhibits humidity-responsive characteristics. Therefore, the polyurea fiber membrane obtained by electrospinning the polyurea elastomer prepared using the embodiments of this invention has sufficient strength and toughness. This polyurea fiber membrane can generate contractile force under the action of water, thereby promoting wound closure. Experiments have shown that when this polyurea fiber membrane is wrapped around a fresh wound, it can tightly adhere to the wound, exhibiting strong adhesion properties, thus meeting the dynamic changes of complex wounds and effectively converting contractile force for wound closure.

[0040] In some embodiments of the present invention, in step S3, the organic solvent is composed of dimethylacetamide and dichloromethane, wherein the volume ratio of dimethylacetamide to dichloromethane is 2:1.

[0041] In some embodiments of the present invention, the specific operation of molding the reaction solution in step S2 includes: pouring the reaction solution into a mold and drying it overnight to obtain the polyurea elastomer.

[0042] In some embodiments of the present invention, the diamine monomer includes at least one of 1,3-diamino-2-propanol, 2,6-diamino-3-pyridinol, and 2-(4,6-diamino-1,3,5-triazin-2-yl)ethanol; the polyetheramine includes at least one of polyetheramine 2000, polyetheramine 300, and polyetheramine 230; and the diisocyanate includes at least one of isophorone diisocyanate, 1,6-hexanediisocyanate, and 4,4-dicyclohexamethylenediisocyanate.

[0043] In some embodiments of the present invention, the molar ratio of the diisocyanate, the polyetheramine, and the diamine monomer is 10:3.4632-7.4074:2.1164-6.0606.

[0044] In some embodiments of the present invention, the electrospinning solution has a mass fraction of 25%.

[0045] In some embodiments of the present invention, in step S4, the electrospinning advance speed is 0.5 ml / h, the voltage is 15 kV, and the distance between the syringe and the collector is 30 cm.

[0046] This invention also provides a polyurea fiber membrane, which is prepared using the polyurea fiber membrane preparation method described above.

[0047] This invention also provides a method for preparing a mechanically active dressing, comprising:

[0048] Step M1: Immerse the polyurea fiber membrane as described above in a dopamine solution, adjust the pH value to 8.5, react at room temperature for 22-26 hours, then wash and dry to obtain a composite fiber membrane;

[0049] Step M2: Immerse the composite fiber membrane in silver ammonia solution, add glucose solution, stir and react for 10-14 hours, then wash and dry to obtain mechanically active dressing.

[0050] Compared with existing technologies, the polyurea fiber membrane prepared in this invention has sufficient strength and toughness. This polyurea fiber membrane can generate contractile force under the action of water, thereby promoting wound closure. Experiments have shown that when this polyurea fiber membrane is wrapped around a fresh wound, it can tightly adhere to the wound, exhibiting strong adhesive properties, thus meeting the dynamic changes of complex wounds and effectively converting contractile force for wound closure. This invention further composites dopamine and Ag nanoparticles onto the polyurea fiber membrane to obtain a mechanically active dressing. Because dopamine has a strong effect on Ag... +With strong adsorption capacity, Ag nanoparticles can uniformly coat the outer wall of the polyurea fiber membrane, allowing them to directly contact bacteria and thus exhibiting good antibacterial effects. Furthermore, the mechanically active dressing provided in this embodiment integrates different compositions and functional zones, achieving both excellent antibacterial properties and sufficient strength and toughness. When this mechanically active dressing is applied to a fresh wound, water stimulates the wound, causing the dressing to absorb water and shrink, thereby promoting wound closure.

[0051] In some embodiments of the present invention, in step M1, the concentration of the dopamine solution is 2 mg / ml.

[0052] This invention also provides a mechanically active dressing, which is prepared using the mechanically active dressing preparation method described above.

[0053] This invention also provides a wound care method, comprising:

[0054] The mechanically active dressing described above is shaped to obtain a temporary shape, resulting in a mechanically active dressing with a temporary shape.

[0055] The temporary mechanically active dressing is wrapped around the wound. Water stimulates the temporary mechanically active dressing to contract, and the contraction force promotes wound closure and reduces bacterial infection.

[0056] In some embodiments of the present invention, the mechanically active dressing is shaped by: wetting the mechanically active dressing, stretching it to a temporary shape, maintaining the stretched state until the moisture evaporates and dries completely, thereby obtaining a mechanically active dressing in a temporary shape.

[0057] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0058] Example 1

[0059] 1.1 Add the polyetheramine solution dropwise to the diisocyanate solution, stir evenly at room temperature, and react for 3 hours to form a prepolymer solution; wherein, the molar ratio of isophorone diisocyanate to polyetheramine 2000 in the prepolymer solution is 10:7.4074;

[0060] The preparation method of the polyetheramine solution includes: dissolving polyetheramine 2000 in N,N-dimethylacetamide, stirring evenly at room temperature, and the mass fraction of polyetheramine 2000 is 50%; the preparation method of the diisocyanate solution includes: dissolving isophorone diisocyanate in N,N-dimethylacetamide, stirring evenly at room temperature, and the mass fraction of isophorone diisocyanate is 50%.

[0061] 1.2. Add a diamine monomer solution to the prepolymer solution, and then react at 50°C for 20 hours. After the reaction is complete, pour the reaction solution into a mold and dry at 80°C for 24 hours to form a polyurea elastomer. The diamine monomer is 1,3-diamino-2-propanol. The molar ratio of isophorone diisocyanate, polyetheramine 2000, and diamine monomer in the reaction solution is 10:7.4074:2.1164. The diamine monomer solution is prepared by dissolving 1,3-diamino-2-propanol in N,N-dimethylacetamide and stirring at room temperature until homogeneous. The mass concentration of 1,3-diamino-2-propanol is 20%.

[0062] 1.3 The polyurea elastomer is dissolved in an organic solvent to obtain an electrospinning solution; the organic solvent is composed of dimethylacetamide and dichloromethane, wherein the volume ratio of dimethylacetamide to dichloromethane is 2:1; the mass fraction of the electrospinning solution is 25%.

[0063] 1.4. Electrospinning is performed using the aforementioned electrospinning solution to obtain a polyurea fiber membrane. A photograph of the polyurea fiber membrane is shown below. Figure 2 During the electrospinning process, the electrospinning speed is 500 r / min, the feed rate is 0.5 ml / h, the voltage is 15 kV, and the distance between the syringe and the collector is 30 cm.

[0064] 1.5. The polyurea fiber membrane was immersed in a dopamine solution, the pH was adjusted to 8.5, and the reaction was carried out at room temperature for 24 hours. The polyurea fiber membrane changed from white to brown. After repeated rinsing with deionized water, it was dried to obtain a composite fiber membrane. The concentration of the dopamine solution was 2 mg / ml.

[0065] 1.6. The composite fiber membrane is immersed in silver ammonia solution, glucose solution is added, and the reaction is stirred for 12 hours. After rinsing the composite fiber membrane repeatedly with deionized water to remove the loose Ag nanoparticles floating on the surface, it is dried to obtain a mechanically active dressing. The preparation process of the silver ammonia solution includes: dissolving AgNO3 solid particles in deionized water to prepare a solution with a concentration of 6-12 g / L, adding ammonia water dropwise while stirring continuously until the solution shows a clear-turbid-clear phenomenon, then stopping the addition to obtain the silver ammonia solution.

[0066] Example 2

[0067] The difference from Example 1 is that the molar ratio of isophorone diisocyanate, polyetheramine 2000 and diamine monomer in the reaction solution is 10:3.4632:6.0606, while all other aspects are the same.

[0068] Experimental Example

[0069] The polyurea fiber membrane prepared in Example 1 was characterized by scanning electron microscopy, and the results are shown in the figure. Figure 3 ,from Figure 3 It can be seen that the average diameter of the fibers in the polyurea fiber membrane is approximately 1.34 μm. When the polyurea fiber membrane prepared in Example 1 is wrapped around a fresh wound, the polyurea fiber membrane can tightly adhere to the wound, exhibiting strong adhesive properties. It can accommodate the dynamic changes of complex wounds and effectively convert contractile force for wound closure. This process is demonstrated in... Figure 4 middle.

[0070] The polyurea fiber membrane prepared in Example 1 was immersed in water for 2 seconds and then removed. A biaxial stretching demonstration was performed on the moistened polyurea fiber membrane. Its area could be stretched to nine times its original size without breaking, demonstrating the strong water-toughening properties of the polyurea fiber membrane. This process was shown in… Figure 5 middle.

[0071] The mechanically active dressing prepared in Example 1 was characterized by scanning electron microscopy, and the results are shown in the figure. Figure 6 ,from Figure 6 As can be seen, Ag nanoparticles are uniformly coated on the outer wall of the fiber, forming a deposition thickness of approximately 270 nm. The mechanically active dressing prepared in Example 1 was applied to the wound, and water spraying stimulated the dressing to contract, using the contractile force to close the wound. This process was demonstrated in… Figure 7 middle.

[0072] The mechanically active dressing from Example 1 was made into a 20mm diameter ring. After wetting the ring, it was stretched to a 40mm diameter ring and held in this stretched state until the moisture evaporated completely. The 40mm diameter ring was then placed on the heart. Water stimulation caused the mechanically active dressing to contract, causing the 40mm ring to recover its shape and shrink back to 20mm, tightly wrapping the heart. This process requires no sutures and exhibits good elasticity, allowing it to accommodate dynamic changes in the heart and achieve monitoring and treatment purposes. This process was demonstrated in… Figure 8 middle.

[0073] Furthermore, it should be noted that although the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a polyurea fiber membrane, characterized in that, include: Step S1: Add the polyetheramine solution to the diisocyanate solution and stir evenly at room temperature to form a prepolymer solution; Step S2: Add a diamine monomer solution to the prepolymer solution, and then react it at a temperature of 20-50°C. After the reaction is completed, allow the reaction solution to solidify to obtain a polyurea elastomer; wherein the side chain of the diamine monomer contains hydrophilic groups. Step S3: Dissolve the polyurea elastomer in an organic solvent to obtain an electrospinning solution; Step S4: Electrospinning is performed using the electrospinning solution to obtain a polyurea fiber membrane; The molar ratio of the diisocyanate, the polyetheramine, and the diamine monomer is 10:3.4632-7.4074:2.1164-6.0606.

2. The method for preparing polyurea fiber membrane according to claim 1, characterized in that, The diamine monomer includes at least one of 1,3-diamino-2-propanol, 2,6-diamino-3-pyridinol, and 2-(4,6-diamino-1,3,5-triazin-2-yl)ethanol.

3. The method for preparing the polyurea fiber membrane according to claim 1, characterized in that, The polyetheramine includes at least one of polyetheramine 2000, polyetheramine 300, and polyetheramine 230; the diisocyanate includes at least one of isophorone diisocyanate, 1,6-hexane diisocyanate, and 4,4-dicyclohexamethylene diisocyanate.

4. The method for preparing the polyurea fiber membrane according to claim 1, characterized in that, The electrospinning solution has a mass fraction of 25%.

5. The method for preparing the polyurea fiber membrane according to claim 1, characterized in that, In step S4, the electrospinning advance speed is 0.5 ml / h, the voltage is 15 kV, and the distance between the syringe and the collector is 30 cm.

6. A polyurea fiber membrane, prepared by the method for preparing a polyurea fiber membrane as described in any one of claims 1-5.

7. A method for preparing a mechanically active dressing, characterized in that, include: Step M1: Immerse the polyurea fiber membrane as described in claim 6 in a dopamine solution, adjust the pH value to 8.5, react at room temperature for 22-26 hours, and then wash and dry to obtain a composite fiber membrane. Step M2: Immerse the composite fiber membrane in silver ammonia solution, add glucose solution, stir and react for 10-14 hours, then wash and dry to obtain mechanically active dressing.

8. The method for preparing the mechanically active dressing according to claim 7, characterized in that, In step M1, the concentration of the dopamine solution is 2 mg / ml.

9. A mechanically active dressing, characterized in that, It is prepared by the method for preparing mechanically active dressings as described in any one of claims 7-8.

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