Process for the preparation of a dope and in-situ deposition of a coating

Abstract

The application provides a spinning dope and a method for in-situ deposition of a dressing. The spinning dope comprises: an alcohol-soluble high-molecular polymer, a hydrophobic silicone high-molecular material, a hydrophobic antibacterial agent and a C2-C3 alcohol solvent. The wound dressing obtained in-situ by electrospinning of the spinning dope has high air permeability, low blood adhesion, superhydrophobicity, antibacterial property, biocompatibility, radiation cooling heat comfort and good conformability to a wound surface.

Description

Technical Field

[0001] This invention belongs to the field of medical dressing technology, specifically relating to a method for a spinning solution and an in-situ deposition dressing. Background Technology

[0002] High wound temperature, water-induced swelling, and bacterial infection can slow the wound healing process, especially in situations such as jungle exploration and emergency rescue. While some commercially available wound dressings, such as hydrogels, porous foams, films, and medicated gauze, can promote wound healing, few effectively address the aforementioned problems. Furthermore, commonly used hydrophilic dressings often cause adhesion to blood clots, leading to pain during dressing changes and hindering effective wound healing. In general applications, patients often need to strictly avoid water contact with the wound to reduce the risk of infection, which can cause potential inconvenience. Electrospun fibers, as an emerging material structure, have been applied to wound dressings due to their inherent high breathability and micro / nanostructure providing waterproofing and breathability to the wound surface. However, most products apply pre-prepared electrospun fibers to the wound, limiting the dressing's conformability. Therefore, it is necessary to provide a new method for preparing electrospun dressings to improve the aforementioned problems. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention aims to provide a method for spinning raw solution and in-situ deposition dressing, thereby obtaining a wound dressing with high air permeability, low blood adhesion, superhydrophobicity, antibacterial properties, biocompatibility, and radiative cooling thermal comfort, and also with good conformity to the wound surface.

[0004] To achieve the above objectives, the present invention provides a spinning solution comprising an alcohol-soluble polymer, a hydrophobic organosilicon polymer, a hydrophobic antibacterial agent, and a C2-C3 alcohol solvent.

[0005] The spinning solution can be deposited in situ on the wound surface to form a dressing. The resulting wound dressing has high conformity to the wound surface and features high breathability, low blood adhesion, superhydrophobicity, antibacterial properties, biocompatibility, and radiative cooling. High breathability helps reduce the stuffiness of the wound surface, superhydrophobicity allows patients to shower or come into contact with water after applying the dressing, low blood adhesion helps reduce pain caused by the adhesion of the dressing to the wound surface tissue during dressing removal, and radiative cooling provides thermal comfort.

[0006] Furthermore, the alcohol-soluble polymer is selected from one or more combinations of polyvinyl butyral, waterborne polyurethane, and alcohol-soluble polyamide.

[0007] Furthermore, the C2-C3 alcohol solvent is selected from ethanol and / or isopropanol.

[0008] Furthermore, the hydrophobic organosilicon polymer material is selected from methyl MQ silicone resin and / or polydimethylsiloxane.

[0009] Furthermore, the hydrophobic antibacterial agent is selected from one or more combinations of hydrophobically treated zinc oxide nanoparticles, titanium dioxide nanoparticles, and silver nanoparticles. The hydrophobic antibacterial agent can be commercially available or prepared in-house. In some optional embodiments, the hydrophobic treatment methods include, but are not limited to, using a silane coupling agent (e.g., hexadecyltrimethylsilane) or a hydrophobic substance (e.g., stearic acid, polydimethylsiloxane, etc.).

[0010] Furthermore, the weight ratio of the alcohol-soluble polymer to the hydrophobic organosilicon polymer is 2:1 to 1:4, for example, it can be 2:1, 2:3, 2:4, 1:1, 1:2, 1:3, or 1:4.

[0011] Further, the hydrophobic antibacterial agent accounts for 0.5% to 5% of the total weight of the alcohol-soluble polymer, the hydrophobic organosilicon polymer, and the hydrophobic antibacterial agent, i.e., the weight of the hydrophobic antibacterial agent / (weight of the alcohol-soluble polymer + weight of the hydrophobic organosilicon polymer + weight of the hydrophobic antibacterial agent) = 0.5% to 5%. In some optional embodiments, the hydrophobic antibacterial agent accounts for 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% of the total weight of the alcohol-soluble polymer, the hydrophobic organosilicon polymer, and the hydrophobic antibacterial agent.

[0012] Further, based on 100 mL of 2-C3 alcohol solvent, the total weight of the alcohol-soluble polymer, the hydrophobic organosilicon polymer, and the hydrophobic antibacterial agent is 5-30 g. In some optional embodiments, based on 100 mL of 2-C3 alcohol solvent, the total weight of the alcohol-soluble polymer, the hydrophobic organosilicon polymer, and the hydrophobic antibacterial agent is 5 g, 10 g, 15 g, 20 g, 25 g, or 30 g.

[0013] Further, the alcohol-soluble polymer, hydrophobic organosilicon polymer, antibacterial agent and C2-C3 alcohol solvent are mixed at 40-60°C for 2-4 hours to obtain the spinning solution.

[0014] The present invention also provides a method for in-situ deposition of a dressing, comprising: using a portable electrospinning device to deposit the aforementioned spinning solution in situ on the wound surface to form a wound dressing.

[0015] The resulting wound dressing exhibits excellent conformability to the wound surface and possesses properties such as high breathability, low blood adhesion, superhydrophobicity, antibacterial properties, biocompatibility, and radiative cooling. High breathability helps reduce the stuffiness of the wound surface; superhydrophobicity allows patients to shower or come into contact with water after applying the dressing; low blood adhesion reduces pain caused by tissue adhesion during dressing changes; and radiative cooling provides thermal comfort. Furthermore, the aforementioned electrospun dressing preparation method is simple, convenient to use, uses readily available raw materials, and is inexpensive.

[0016] In some alternative embodiments, the aforementioned portable electrospinning equipment may be a commercially available portable electrospinning machine or a self-made portable electrospinning machine, without any special limitation.

[0017] Furthermore, in-situ deposition is carried out at voltages of 6–15 kV, such as 6 kV, 7 kV, 8 kV, 9 kV, 10 kV, 11 kV, 12 kV, 13 kV, 14 kV, or 15 kV.

[0018] Furthermore, the receiving distance between the portable electrospinning device and the wound surface is 5 to 25 cm, for example, 5 cm, 10 cm, 15 cm, 20 cm or 25 cm. Attached Figure Description

[0019] Figure 1 This is a photograph of dressing deposition during Embodiment 1 of the present invention.

[0020] Figure 2 This is an optical image of the water droplet rolling angle test of the dressing obtained in Embodiment 1 of the present invention.

[0021] Figure 3 This is a scanning electron microscope image of the surface of the dressing obtained in Example 2 of the present invention.

[0022] Figure 4 This is an optical diagram of the water droplet contact angle of the dressing obtained in Embodiment 2 of the present invention.

[0023] Figure 5 The images show the reflectance of the ultraviolet-visible-near-infrared spectra of the dressings and gauze obtained in Example 2 of this invention, as well as the infrared emissivity spectra with integrating spheres.

[0024] Figure 6 Infrared imaging photographs of the arm with dressing and the arm with gauze in Embodiment 2 of the present invention under solar irradiation.

[0025] Figure 7 This is an optical image of the contact angle between blood and blood clot in the dressing obtained in Embodiment 2 of the present invention.

[0026] Figure 8This is a scanning electron microscope image of the contact area between the dressing and the blood clot obtained in Embodiment 2 of the present invention.

[0027] Figure 9 The images are fluorescence micrographs of mouse fibroblasts after the dressing and gauze obtained in Example 2 of this invention were stained and cultured for 1, 3, and 5 days.

[0028] Figure 10 This is a photograph showing the distribution of colonies of the dressing and gauze obtained in Example 2 of the present invention on an agar plate after co-culturing with Escherichia coli and Staphylococcus aureus. Detailed Implementation

[0029] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0030] Example 1

[0031] This embodiment provides a method for in-situ deposition of dressings, which includes the following steps:

[0032] 0.8 g of waterborne polyurethane (waterborne polyurethane film dried from McLean A909856 waterborne polyurethane emulsion), 0.8 g of polydimethylsiloxane, and 0.08 g of surface-hydrophobic modified silver nanoparticles (5 g of silver nanoparticles were added to 100 mL of hexadecyltrimethylsilane solution (solvents were ethanol and water, with a volume ratio of 4:1 and a mass concentration of 1% hexadecyltrimethylsilane), heated to 40 °C, stirred for 2 hours, the white precipitate was separated by centrifugation, the precipitate was washed repeatedly with ethanol, and further dried at 60 °C for 10 hours to obtain surface-hydrophobic modified silver nanoparticles) were added to 10 mL of ethanol solvent and stirred at 50 °C for 4 hours to obtain a high-viscosity spinning solution (approximately 500 cp), which was then stored at room temperature for later use.

[0033] Using a commercially available portable electrospinning machine (PolyNada HHE-1), the above-mentioned spinning solution was deposited in situ on the skin surface at a voltage of 12kV (e.g., Figure 1 As shown), a dressing is formed, wherein the receiving distance is 20cm.

[0034] Spinning speed test: Using the aforementioned portable electrospinning equipment and spinning solution, the maximum spinning speed was tested at 12kV by connecting the equipment to a uniform-speed injection pump. The maximum spinning speed was found to be approximately 5mL / h. This demonstrates that it can deposit dressings onto the wound surface relatively quickly.

[0035] Hydrophobic property characterization: Figure 2 An optical diagram of the water droplet roll-off angle of the dressing is shown, with a roll-off angle of 9.1°, indicating that the dressing has superhydrophobic properties.

[0036] Example 2

[0037] This embodiment provides a method for in-situ deposition of dressings, which includes the following steps:

[0038] Add 0.7g of polyvinyl butyral, 1.4g of methyl MQ silicone resin, and 0.1g of stearic acid-coated zinc oxide (KONADA, KND-IB30) to 10mL of ethanol solvent, stir at 60℃ for 3h to obtain a spinning solution with a certain viscosity (about 300cp), and set it at room temperature for later use.

[0039] Using a commercially available portable electrospinning machine (PolyNada HHE-1), the above-mentioned spinning solution was deposited in situ on the skin surface at a voltage of 15kV to form a dressing, with a receiving distance of 15cm.

[0040] Morphological characteristics: Figure 3 A scanning electron microscope image of the dressing surface is shown, revealing that the dressing has a distinct fibrous structure.

[0041] Hydrophobic property characterization: Figure 4 An optical diagram of the water droplet contact angle of the dressing is shown, with a contact angle of 154°, indicating superhydrophobic properties.

[0042] Air permeability test: The air permeability of the dressing and gauze was tested separately using the positive cup method. At 35℃, the water vapor transmission rate of the dressing was 5976 gm. -2 d -1 The water vapor transmission rate of the gauze was 6236 gm. -2 d -1 The two are quite similar.

[0043] Radiative cooling capacity test: The reflectance of the ultraviolet-visible-near-infrared spectrum and the emissivity of the infrared spectrum with an integrating sphere were tested for the dressing and gauze respectively. The results are as follows: Figure 5 As shown, the dressing has 95% reflectance in the solar spectrum, while gauze has only 48%. In the mid-infrared band of 8-13 micrometers, the dressing has 86% emissivity.

[0044] Actual radiative cooling performance test under sunlight: One volunteer's arm was covered with the aforementioned dressing, and the other with gauze. The arm was exposed to sunlight at midday on a sunny day, and the surface temperature of each arm was photographed using an infrared camera. The images obtained from the infrared camera are shown below. Figure 6 As shown, the arm with the above dressing was 33.1℃ under an infrared camera, while the gauze was 36.2℃. It is evident that compared to thick gauze, the above dressing can effectively reduce the temperature of the wound surface.

[0045] Anti-blood adhesion test: 0.2 mL of blood was dropped onto the dressing, and the contact angle of the blood on the surface of the wound dressing and the contact angle of the blood clot on the surface of the wound dressing after coagulation were measured. Contact angle images are shown below. Figure 7 As shown, the dressing exhibits strong blood repellency and maintains a large contact angle even as the blood coagulates. Scanning electron micrographs of the contact area between the blood clot and the wound dressing are shown below. Figure 8 As shown, the blood clot adheres to the dressing surface locally point-to-point, which helps reduce the adhesion between the blood and the dressing.

[0046] Cell compatibility testing: The cell compatibility of the dressing with gauze was evaluated using mouse fibroblasts. Mouse fibroblasts were cultured in culture medium and stored at 37°C with 5% CO2. Both samples were immersed in cell-containing culture medium for 1, 3, and 5 days. Subsequently, the state of the cells in the culture medium was observed using confocal microscopy. Fluorescence micrographs of stained mouse fibroblasts are shown below. Figure 9 As shown, both samples exhibit good cell compatibility.

[0047] Antibacterial test: Staphylococcus aureus and Escherichia coli were used as research subjects. A concentration of 1.88 × 10⁻⁶ was applied. 7 CFU / mL bacterial suspension was incubated with the dressing and gauze in an incubator. Bacterial inhibition rate was assessed by analyzing bacterial formation. Bacterial viability was determined using ImageJ software. The distribution of *E. coli* and *Staphylococcus aureus* colonies on agar plates after co-culturing with the two dressings is shown in the image. Figure 10 As shown, the dressing exhibits inhibition rates of 95.62% and 99.58% against Escherichia coli and Staphylococcus aureus, respectively, while gauze has virtually no antibacterial properties.

Claims

1. A spinning solution, wherein, This includes alcohol-soluble polymers, hydrophobic organosilicon polymers, hydrophobic antibacterial agents, and C2-C3 alcohol solvents.

2. The spinning solution according to claim 1, wherein, The hydrophobic organosilicon polymer material is selected from methyl MQ silicone resin and / or polydimethylsiloxane.

3. The spinning solution according to claim 1, wherein, The hydrophobic antibacterial agent is selected from one or more of the following: hydrophobically treated zinc oxide nanoparticles, titanium dioxide nanoparticles, and silver nanoparticles.

4. The spinning solution according to claim 1, wherein, The alcohol-soluble polymer is selected from one or more combinations of polyvinyl butyral, waterborne polyurethane, and alcohol-soluble polyamide; and / or, The C2-C3 alcohol solvent is selected from ethanol and / or isopropanol.

5. The spinning solution according to claim 1, wherein, The weight ratio of the alcohol-soluble polymer to the hydrophobic organosilicon polymer is 2:1 to 1:

4.

6. The spinning solution according to claim 1, wherein, The hydrophobic antibacterial agent comprises 0.5% to 5% of the total weight of the alcohol-soluble polymer, the hydrophobic organosilicon polymer, and the hydrophobic antibacterial agent; and / or, Based on 100 mL of the C2-C3 alcohol solvent, the total weight of the alcohol-soluble polymer, the hydrophobic organosilicon polymer, and the hydrophobic antibacterial agent is 5-30 g.

7. The spinning solution according to claim 1, wherein, The alcohol-soluble polymer, the hydrophobic organosilicon polymer, the antibacterial agent, and the C2-C3 alcohol solvent are mixed at 40-60°C for 2-4 hours to obtain the spinning solution.

8. A method for in-situ deposition of a dressing, wherein, include: A portable electrospinning device is used to deposit the spinning solution of any one of claims 1 to 7 in situ on the wound surface to form a wound dressing.

9. The method for in-situ deposition of dressings according to claim 8, wherein, The in-situ deposition was performed at a voltage of 6–15 kV.

10. The method for in-situ deposition of dressings according to claim 8, wherein, The portable electrospinning device is 5 to 25 cm away from the wound surface.

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