A multifunctional wound patch combined with electrical stimulation therapy and its preparation method and application

Abstract

The present invention discloses a multifunctional wound patch for combined electrical stimulation therapy, as well as its preparation method and application, and relates to the field of medical material technology. The multifunctional wound patch comprises a double-layer electrospun fiber membrane, a conductive ink layer, and a conductive hydrogel layer. The surface of the hydrophobic fiber layer (the side directly contacting the wound) is integrated with a pair of serpentine concentric conductive electrodes written with conductive ink, and the ends of the two electrodes can be drawn with square conductive ports of corresponding sizes as needed. The surface of the conductive electrode pair is encapsulated with a conductive hydrogel with antibacterial function. External electrical signals can be transmitted to the electrode pair of the patch through the conductive ports of the electrode pair, and then act on the wound through the conductive hydrogel layer to achieve on-demand electrical stimulation treatment of the wound. The multifunctional wound patch for combined electrical stimulation therapy prepared by the present invention can achieve the discharge of excess exudate and ensure a good wound environment; the loaded curcumin drug has antibacterial, antioxidant, and healing effects on the wound.

Description

Technical Field

[0001] The present invention relates to a multifunctional wound patch combined with electrical stimulation therapy, a preparation method and application thereof, and belongs to the technical field of medical materials. Background Art

[0002] The healing process of chronic wounds (such as diabetic ulcers, pressure sores, and venous ulcers) and acute wounds is complex and affected by multiple factors, including infection, inflammation, and circulatory impairment. Traditional dressings (such as gauze and hydrocolloid dressings) only passively protect the wound surface and fail to actively intervene in the healing microenvironment, resulting in prolonged healing and high recurrence rates. Furthermore, many chronic wounds often produce excessive exudate. Traditional dressings lack the ability to drain exudate. After absorbing exudate, these dressings can leak back into the wound, leading to accumulation and infection, as well as adhesion between the dressing and the wound. This can hinder wound healing and can cause secondary injury and pain to the patient during dressing changes. According to statistics, the global number of chronic wound patients is increasing by 8%-10% annually, necessitating an urgent need for innovative treatments. Single treatment modalities (such as antimicrobial and moisturizing) are insufficient to meet the needs of complex wounds. To achieve multifunctional patches, advanced material design and preparation are required. Existing integrated circuit wound patches are made from dense membranes, which have poor air permeability and allow exudate accumulation at the wound site, hindering wound healing and even worsening the wound microenvironment, making it difficult to heal. Micro-nanofiber membranes produced through electrospinning technology, on the other hand, are porous and can be loaded with anti-inflammatory and antibacterial drugs. Their ease of preparation makes them promising for wound treatment. Furthermore, studies have shown that appropriate electrical stimulation (field strength of 50-100 mV / cm) can promote fibroblast migration, enhance angiogenesis, and inhibit bacterial biofilms. However, existing electrical stimulation devices are mostly large desktop instruments that require hospital use, and direct contact between electrodes and wounds can cause secondary damage. Stretchable circuits and printed electrodes are laying the foundation for flexible electrical stimulation patches, while conductive hydrogels can achieve dual electrical and chemical signal responses, providing a carrier for combined therapy. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the first object of the present invention is to provide a method for preparing a multifunctional wound patch combined with electrical stimulation therapy, comprising the following steps:

[0004] S1: Preparation of hydrophilic electrospun fiber membrane layer;

[0005] Dissolving polyurethane and polyoxyethylene polyoxypropylene ether (F127) in a mass ratio of 4-5:1 in 10 mL of a binary organic solvent and stirring until completely dissolved to obtain an electrospinning solution for a hydrophilic electrospinning fiber membrane with a concentration of 12 wt%-20 wt%, and subjecting the obtained electrospinning solution for the hydrophilic electrospinning fiber membrane to an electrospinning treatment to obtain a hydrophilic electrospinning fiber membrane layer;

[0006] S2: Continuously performing electrospinning on the hydrophilic electrospun fiber membrane layer to obtain a drug-loaded hydrophobic electrospun fiber membrane layer;

[0007] Dissolve polyurethane and curcumin in 10 mL of a binary organic solvent and stir at room temperature until completely dissolved to obtain an electrospinning solution of a drug-loaded hydrophobic electrospun fiber membrane with a concentration of 12 wt%-20 wt%, wherein the mass fraction of curcumin in the solute polyurethane is 5%-15%, and continuously electrospinning is performed on the hydrophilic electrospun fiber membrane layer to obtain a drug-loaded hydrophobic electrospun fiber membrane layer;

[0008] S3: Directly writing a serpentine concentric circle conductive ink layer on the drug-loaded hydrophobic electrospun fiber membrane layer;

[0009] Conductive silver ink is used as the conductive material, the writing speed is 10-30 mm / min, and the air pressure is 2-5Kg / cm 2 ;

[0010] S4: Writing a conductive hydrogel layer on the serpentine concentric circle conductive ink layer;

[0011] The conductive hydrogel material is composed of polyvinyl alcohol, phytic acid, tannic acid, zinc chloride and glycerol; the writing speed is 1-5mm / min, and the air pressure is 3-5Kg / cm 2 .

[0012] Preferably, the electrospinning process parameters in steps S1 and S2 are: receiving distance 10-15 cm, voltage 15-20 kV, pushing speed 0.6-1.2 mL / h, temperature 20-30 ° C, humidity below 50%, drum speed 100-200 r / min, and spinning time 1-5 h.

[0013] Preferably, the binary organic solvent in steps S1 and S2 is an organic solution composed of N,N-dimethylformamide and dichloromethane in a volume ratio of 1-9:1.

[0014] Using the above technical solution, the drug-loaded hydrophobic electrospun fiber membrane layer of the present invention is made of polyurethane, and the drug is curcumin, which is hydrophobic. The hydrophilic electrospun fiber membrane layer is made of a hydrophobic material and a hydrophilic material, wherein the hydrophilic material is polyoxyethylene polyoxypropylene ether (F127) and the hydrophobic material is polyurethane (PU). Because the two-layer fiber membrane with different hydrophilic and hydrophobic properties is prepared using the same hydrophobic material, and the second drug-loaded hydrophobic layer is electrospun immediately after the first hydrophilic layer is spun, the organic solvent in the hydrophilic layer is not fully volatilized, which acts as a bond to the hydrophobic layer. As a result, the two-layer fiber membrane has a stronger interlayer bond and is less prone to delamination when stretched, eliminating the need for a binder to bond the hydrophilic and hydrophobic layers.

[0015] Preferably, after writing is completed in step S3, the fiber film is placed in a blast drying oven and dried at 60° C. for 1-2 hours to evaporate the organic solvent in the conductive silver paste.

[0016] Preferably, in the conductive hydrogel material of step S4, the concentration of polyvinyl alcohol is 8wt%-12wt%, the mass ratio of phytic acid to polyvinyl alcohol is 0.5-1:1, and the mass ratio of tannic acid to polyvinyl alcohol is 0.05-0.1:1.

[0017] Using the above technical solution, the drug-loaded hydrophobic electrospun fiber membrane layer is composed of a hydrophobic material polyurethane PU with good elasticity and biocompatibility and a hydrophobic drug curcumin with antibacterial and antioxidant effects. It is located on the side near the wound to allow wound exudate to pass through and prevent reverse osmosis of the exudate. The hydrophilic electrospun fiber membrane layer is prepared by polyurethane PU and a hydrophilic small molecule material polyoxyethylene polyoxypropylene ether F127 in a certain proportion. It is located on top of the drug-loaded hydrophobic electrospun fiber membrane layer, and the two layers of fiber membranes are tightly combined. When the two layers of fiber membrane come into contact with the exudate at the wound, the exudate will be directed from the hydrophobic layer to the hydrophilic layer due to the different hydrophilic and hydrophobic properties of the two layers of fiber membranes, and will not reversely osmosis to the hydrophobic layer, thereby draining away excess exudate from the wound, ensuring a dry and comfortable environment at the wound and promoting wound healing. The hydrophobic layer is loaded with curcumin and is released during contact with the exudate, achieving antibacterial, anti-inflammatory and antioxidant effects at the wound, further promoting wound healing.

[0018] The second purpose of the present invention is to provide a multifunctional wound patch for combined electrical stimulation therapy prepared by the above method, wherein the multifunctional wound patch comprises a double-layer electrospun fiber membrane, a conductive ink layer and a conductive hydrogel layer, wherein the double-layer electrospun fiber membrane comprises a hydrophilic electrospun fiber membrane layer and a drug-loaded hydrophobic electrospun fiber membrane layer, and the multifunctional wound patch comprises, from top to bottom, a hydrophilic electrospun fiber membrane layer, a drug-loaded hydrophobic electrospun fiber membrane layer, a conductive ink layer and a conductive hydrogel layer, and the adjacent two layers are tightly combined.

[0019] Preferably, the thickness of the hydrophilic electrospun fiber membrane layer is 25-40 μm, and the thickness of the drug-loaded hydrophobic electrospun fiber membrane layer is 20-35 μm.

[0020] Preferably, the conductive ink layer is a serpentine concentric circle conductive ink layer, the diameter of the center circle is 2 mm, the radius from the center of the center circle to the outermost side of the serpentine ring is 10 mm, the radius from the center of the center circle to the innermost side of the serpentine ring is 8 mm, the line width is 1 mm, and the end interface is 4 mm long and 3 mm wide.

[0021] Preferably, the conductive hydrogel layer has a center diameter of 4 mm, a line width of 2 mm, and a thickness of 0.1 mm.

[0022] Using the above technical solution, the multifunctional wound patch comprises a double-layer electrospun fiber membrane (a drug-loaded hydrophobic layer and a hydrophilic layer), a conductive ink layer, and a conductive hydrogel layer. The double-layer fiber membrane forms the main body of the wound patch, facilitating the directional drainage of exudate from the wound, preventing reverse leakage and accumulation of exudate in the wound, which can lead to infection or adhesion. Furthermore, the porous structure of the fiber membrane effectively improves the breathability of the entire wound dressing. Furthermore, the surface of the hydrophobic fiber layer (the side directly contacting the wound) is integrated with a pair of concentric, serpentine conductive electrodes inscribed with conductive ink. One of the electrodes is a ring-shaped serpentine electrode, and the other is a central circle electrode. Square conductive ports of corresponding sizes can be drawn on the ends of both electrodes as needed. The surface of the conductive electrode pair is further encapsulated with a conductive hydrogel with antibacterial properties. External electrical signals (voltage or current of a specific waveform) can be transmitted to the patch's electrode pair through the conductive ports, where they are then applied to the wound through the conductive hydrogel layer, achieving on-demand electrical stimulation therapy for the wound. Moreover, the conductive port can be connected to the test instrument, and the impedance monitoring of the wound can be achieved using the conductive electrode pair, and the stage of the wound can be analyzed by the change of the skin-wound impedance. The conductive electrode pair encapsulated by the conductive hydrogel can prevent the conductive ink from falling off and enhance the ability of the conductive electrode to resist deformation; at the same time, the conductive hydrogel with antibacterial function also enhances the fit of the electrode on the fiber dressing to the wound surface, giving the fiber-based dressing stronger conformability and comfort. And the antibacterial property of the gel itself can also ensure that the patch effectively inhibits bacterial growth during long-term use. In addition, the drugs contained in the hydrophobic fibers of the wound patch can be continuously released at the wound, effectively promoting wound healing. This multifunctional fiber-based wound patch with combined electrical stimulation provides an effective solution for promoting wound healing, especially the healing of chronic wounds.

[0023] The multifunctional wound patch of this invention can be connected to a multimeter to monitor wound impedance, analyzing the wound's stage through changes in skin-wound impedance. During the inflammatory phase, exudate increases, blood cell aggregation, and edema occur, leading to a significant decrease in low-frequency impedance (<10 kHz). During the proliferative phase, granulation tissue forms (new blood vessels, fibroblasts, and collagen), and the mid- and high-frequency impedance (10-100 kHz) increases. During the maturation phase, collagen remodeling and scar formation (low vascular density) occur, and the high-frequency impedance (>100 kHz) approaches that of normal skin (or slightly higher).

[0024] Beneficial effects of the present invention:

[0025] The present invention produces a multifunctional wound patch combined with electrical stimulation therapy, which can achieve the discharge of excess exudate and ensure a good wound environment; the loaded curcumin drug has antibacterial, antioxidant and healing effects on the wound; the conductive hydrogel encapsulated silver paste can prevent the silver paste from falling off and enhance the electrode's resistance to deformation; at the same time, the conductive hydrogel enhances the electrode fit and conformability on the fiber dressing, as well as the antibacterial and comfort properties for long-term use. In addition, wound information is digitized by monitoring wound impedance, and the treatment plan is adjusted based on the wound impedance information. The relevant parameters of electrical stimulation are dynamically adjusted to achieve the optimal strategy for wound treatment. Ultimately, it will help medical staff provide patients with more timely and personalized treatment strategies, accelerate wound healing, and reduce the burden on patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the exploded structure of the multifunctional wound patch of the present invention;

[0027] Figure 2 This is a diagram showing the key dimensions of the multifunctional wound patch of the present invention;

[0028] Figure 3 Schematic diagram of the treatment process of the multifunctional wound patch of the present invention;

[0029] Figure 4 The SEM image and water contact angle image of the hydrophilic electrospun fiber membrane layer provided in Example 1 of the present invention;

[0030] Figure 5 The SEM image and water contact angle image of the drug-loaded hydrophobic electrospun fiber membrane layer provided in Example 1 of the present invention;

[0031] Figure 6 This is a graph showing the test results of the one-way drainage capacity of the sample provided in Example 1 of the present invention;

[0032] Figure 7 This is a graph showing the test results of the anti-gravity one-way drainage capacity of the sample provided in Example 1 of the present invention;

[0033] Figure 8 This is a qualitative result diagram of drug release of the sample provided in Example 1 of the present invention;

[0034] Figure 9 This is a graph showing the quantitative drug release results of the sample provided in Example 1 of the present invention;

[0035] Figure 10 Graph showing the air permeability test results of samples provided in Example 1 and Comparative Examples 1 to 5 of the present invention;

[0036] Figure 11 The cell compatibility test results of the samples provided in Control Group 1, Example 1 and Example 2 of the present invention;

[0037] Figure 12 This is a diagram of the lighting of a small light bulb of the sample provided in Comparative Example 6 and Example 2 of the present invention;

[0038] Figure 13 Graphs showing the conductivity of each group of hydrogels in Experimental Example 4 of the present invention;

[0039] Figure 14 The bacterial colonies of the samples provided in Control Group 2 and Example 2 of the present invention;

[0040] Figure 15 This is the one-way drainage effect of the products of Example 3 of the present invention and Comparative Example 10 on the skin;

[0041] Figure 16 The electrical output performance results of the product of Example 3 of the present invention;

[0042] Figure 17 This is a diagram showing impedance detection and electrical stimulation treatment of a mouse wound using the product of Example 3 of the present invention;

[0043] Figure 18 This is a physical picture of the wound patch in Test Example 6 of the present invention when stretched;

[0044] Figure 19 This is a diagram of water diffusion under vacuum for the wound patch of the present invention;

[0045] Figure 20 This is a diagram showing the failure of the wound patch of the present invention to drain liquid in one direction on the skin after vacuum drying;

[0046] Figure 21 This is a diagram showing the effect of the wound patch of the present invention on unidirectional drainage of exudate from a mouse wound;

[0047] In the figure: 1-hydrophilic electrospun fiber membrane layer, 2-drug-loaded hydrophobic electrospun fiber membrane layer, 3-conductive ink layer, 4-conductive hydrogel layer. DETAILED DESCRIPTION

[0048] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0049] Example 1

[0050] A method for preparing an electrospun double-layer fiber membrane comprises dissolving 1.5 g of polyurethane and 0.3 g of F127 in 10 mL of a binary organic solvent (N,N-dimethylformamide: dichloromethane, volume ratio: 7:3) and magnetically stirring at room temperature for 6-8 hours until completely dissolved, yielding an electrospinning solution with a concentration of 18 wt% for the hydrophilic electrospun fiber membrane. Furthermore, dissolving 1.5 g of polyurethane and 0.167 g of curcumin in 10 mL of a binary organic solvent (N,N-dimethylformamide: dichloromethane, volume ratio: 7:3) and magnetically stirring at room temperature for 6-8 hours until completely dissolved, yielding an electrospinning solution with a concentration of 16 wt% for the drug-loaded hydrophobic electrospun fiber membrane. The mass fraction of curcumin in the polyurethane solute is 10%. The electrospinning solution for the resulting hydrophilic electrospun fiber membrane was electrospun at an ambient temperature of 25°C and a relative humidity of 40%-50%. The electrospinning parameters were 19 kV, a receiving distance of 15 cm, a push speed of 1 mL / h, and a drum speed of 200 rpm. The receiving substrate was aluminum foil, and the spinning time was 2 hours. Subsequently, a drug-loaded hydrophobic electrospun fiber membrane was electrospun sequentially on top of the hydrophilic electrospun fiber membrane layer. The electrospinning parameters were largely the same as those for the hydrophilic layer, except that the voltage was 20 kV and the spinning time was 2 hours. Finally, the fiber membrane was transferred to a vacuum drying oven to dry and remove the organic solvent from the fiber membrane.

[0051] Example 2

[0052] A method for preparing a conductive hydrogel involves adding 0.6 mL of phytic acid (50% in water), 0.3 mL of 0.05 mol / L ZnCl2, 0.95 g of polyvinyl alcohol (1799 type), and 0.05 g of tannic acid to 6.1 mL of a solution containing deionized water and glycerol in a 4:1 volume ratio. The mixture is then magnetically stirred at 90°C for 2 hours until the solution is completely dissolved. The hydrogel precursor is then poured into a mold and subjected to repeated freeze-thaw cycles to obtain the finished hydrogel.

[0053] Example 3

[0054] A method for preparing a multifunctional wound patch combined with electrical stimulation therapy is as follows:

[0055] S1: Preparation of hydrophilic electrospun fiber membrane by electrospinning

[0056] The hydrophilic electrospun fiber membrane layer was constructed using a hydrophobic polyurethane material and the hydrophilic small molecule F127. 1.5 g of polyurethane and 0.3 g of F127 were dissolved in 10 mL of a binary organic solvent consisting of N,N-dimethylformamide and dichloromethane in a volume ratio of 7:3. The solution was magnetically stirred at room temperature for 6-8 hours until completely dissolved, yielding an electrospinning solution with an 18 wt% concentration for the hydrophilic electrospinning fiber membrane. The solution was electrospun at an ambient temperature of 25°C and a relative humidity of 40%-50%. The electrospinning parameters were 19 kV, a receiving distance of 15 cm, a push speed of 1 mL / h, and a drum speed of 200 r / min. The receiving substrate was aluminum foil, and the spinning time was 2 hours.

[0057] S2: Preparation of drug-loaded hydrophobic electrospun fiber membrane by electrospinning

[0058] The drug-loaded hydrophobic electrospun fiber membrane layer was constructed using a hydrophobic polyurethane and curcumin. 1.5 g of polyurethane and 0.167 g of curcumin were dissolved in 10 mL of a binary organic solvent consisting of N,N-dimethylformamide and dichloromethane (7:3 by volume). The solution was magnetically stirred at room temperature for 6-8 hours until completely dissolved, resulting in an electrospinning solution with a concentration of 16 wt% for the drug-loaded hydrophobic electrospun fiber membrane. The mass fraction of curcumin in the polyurethane solution was 10%. The electrospinning process was performed at an ambient temperature of 25°C and a relative humidity of 40%-50%. The electrospinning parameters were 20 kV, a receiving distance of 15 cm, a push speed of 1 mL / h, and a drum speed of 200 r / min. The receiving substrate was aluminum foil, and the spinning time was 2 hours.

[0059] After the hydrophilic electrospun fiber membrane is electrospun, a drug-loaded hydrophobic electrospun fiber membrane must be prepared immediately on top of the hydrophilic layer. This is because the organic solvent in the hydrophilic layer has not fully evaporated, causing adhesion to the subsequent hydrophobic layer fibers. The prepared double-layer electrospun fiber membrane is placed in a vacuum drying oven and evacuated for at least 30 minutes to remove the organic reagents from the fiber membrane.

[0060] S3: Directly writing a serpentine concentric circle conductive ink layer on the drug-loaded hydrophobic electrospun fiber membrane layer

[0061] Remove the double-layer fiber membrane from the vacuum drying oven after draining the organic solvent, ensure that the drug-loaded hydrophobic electrospun fiber membrane layer is on top, and securely place it on the writing machine platform. Conductive silver ink is used as the conductive material, and the inner diameter of the needle is 0.34 mm. In some embodiments, the writing parameters meet the following requirements: writing speed of 10-30 mm / min, air pressure of 2-5 kg / cm 2 A serpentine concentric circle conductive silver paste layer was written on the drug-loaded hydrophobic electrospun fiber membrane. After writing, the fiber membrane was placed in a forced air drying oven at 60°C for 1-2 hours to evaporate the organic solvent in the conductive silver paste.

[0062] S4: Writing a conductive hydrogel layer on the serpentine concentric circle conductive ink layer

[0063] (1) Preparation of conductive hydrogel precursor

[0064] The conductive hydrogel material uses polyvinyl alcohol, phytic acid, tannic acid, zinc chloride, and glycerol, all of which have excellent biosafety. Phytic acid can improve the conductivity of the hydrogel, while tannic acid has antioxidant effects and zinc chloride has antibacterial effects, resulting in a good wound healing effect. The concentration of the polyvinyl alcohol is 8wt%-12wt%, the mass ratio of phytic acid to polyvinyl alcohol is 0.5-1:1, and the mass ratio of tannic acid to polyvinyl alcohol is 0.05-0.1:1. The preferred ratio is: 0.6 mL of phytic acid (50% in water), 0.3 mL of 0.05 mol / L ZnCl2, 0.95 g of polyvinyl alcohol (type 1799), and 0.05 g of tannic acid are added to 6.1 mL of a solution containing 6.1 mL of deionized water and glycerol in a volume ratio of 4:1. The mixture is magnetically stirred at 90°C for 2 hours until the solution is completely dissolved.

[0065] (2) Conductive hydrogel is written onto the conductive silver ink layer

[0066] The dried fiber membrane containing the conductive silver paste layer is placed on the writing platform, ensuring that the conductive silver paste layer side is on top. The conductive hydrogel precursor prepared by direct ink writing technology (such as a dispensing machine, 3D printing system, etc.) is extruded through a needle and written on the preset annular concentric serpentine electrode pair area, where the inner diameter of the needle is 0.34 mm. In some embodiments, the writing parameters meet the following requirements: writing speed of 1-5 mm / min, air pressure of 3-5 kg / cm 2 The written device was placed in a dry sealed box, and then placed in a -20℃ refrigerator for 2 h, then taken out and thawed at room temperature for 2 h, and repeated freezing and thawing 3 times.

[0067] Since the hydrogel substrate is made of polyvinyl alcohol, polyvinyl alcohol and phytic acid need to be mixed evenly and then repeatedly frozen and thawed to generate a large number of hydrogen bonds to form a hydrogel. If the integrated device with written gel is placed directly in the refrigerator, the moisture in the refrigerator will soak the double-layer fiber membrane, and the one-way drainage function will be destroyed. Therefore, the written device needs to be placed in a dry and sealed box, then placed in the refrigerator to freeze, taken out and thawed at room temperature. In addition, the device with written gel cannot be sealed in a vacuum drying bag, because under the action of vacuum, the water in the hydrogel will be squeezed out and diffused onto the double-layer fiber membrane, and the one-way drainage function will also be destroyed. Therefore, the device after freeze-thawing needs to be placed in a sealed box for the next step.

[0068] The multifunctional wound patch can be connected to a multimeter to monitor wound impedance, analyzing the wound's stage through changes in skin-wound impedance. During the inflammatory phase, exudate increases, blood cell aggregation, and edema occur, leading to a significant decrease in low-frequency impedance (<10kHz). During the proliferative phase, granulation tissue forms (neovascularization, fibroblasts, collagen), and medium- and high-frequency impedance (10-100kHz) increases. During the maturation phase, collagen remodeling and scar formation (low vascular density) occur, and high-frequency impedance (>100kHz) approaches that of normal skin (or slightly higher).

[0069] Example 4

[0070] A multifunctional wound patch comprises a double-layer electrospun fiber membrane, a conductive ink layer and a conductive hydrogel layer. The double-layer electrospun fiber membrane comprises a hydrophilic electrospun fiber membrane layer 1 and a drug-loaded hydrophobic electrospun fiber membrane layer 2. The multifunctional wound patch comprises, from top to bottom, a hydrophilic electrospun fiber membrane layer 1, a drug-loaded hydrophobic electrospun fiber membrane layer 2, a conductive ink layer 3 and a conductive hydrogel layer 4, and the adjacent two layers are tightly combined.

[0071] like Figure 1-Figure 3As shown, the multifunctional wound patch is composed of a double-layer electrospun fiber membrane as the substrate. The thickness of the hydrophilic electrospun fiber membrane layer 1 is preferably 25-40 μm, and the thickness of the drug-loaded hydrophobic electrospun fiber membrane layer 2 is preferably 20-35 μm. A serpentine concentric circle conductive ink layer 3 is applied to the drug-loaded hydrophobic electrospun fiber membrane layer 2. The diameter of the center circle is 2 mm, the radius from the center of the center circle to the outermost side of the serpentine ring is 10 mm, and the radius from the center of the center circle to the innermost side of the serpentine ring is 8 mm. The line width is 1 mm, and the end interface is 4 mm long and 3 mm wide. Because the conductive ink will penetrate into the inner side of the fiber, the thickness of the conductive ink layer is negligible. A conductive hydrogel layer 4 is encapsulated on the conductive ink layer, with a center diameter of approximately 4 mm, a line width of 2 mm, and a thickness of 0.1 mm. The organic solvent in the conductive ink will partially dissolve and bond with the fiber membrane, while the polyvinyl alcohol in the hydrogel contains a large number of hydrogen bonds, which can form hydrogen bonds with the conductive ink and the polar groups on the fiber surface, thereby enhancing the intermolecular force and generating viscosity, so that the layers are tightly bonded and will not delaminate or fall off due to use. Due to the porous structure of the fiber membrane, the conductive ink can penetrate and diffuse into the fiber membrane. After ordinary conductive ink is written and solidified on the fiber membrane, the conductive circuit is prone to cracking or a sharp increase in resistance after the fiber membrane is bent or stretched. The use of stretchable conductive ink can improve the stretchability of the device. In order to prevent the conductive material from falling off after being rubbed on the skin and affecting the resistance performance, a layer of conductive hydrogel is encapsulated on the conductive ink. This can not only protect the conductive ink layer and improve wear resistance, but also form a better fit with the skin due to the flexibility and adaptability of the hydrogel, effectively transmit electrical properties, and enhance the electrode's ability to resist deformation. The designed serpentine structure can enhance the patch's ductility; the annular concentric structure can form a centripetal electric field, which makes the electric field more concentrated on the wound area, ensuring that the entire wound surface receives uniform electrical stimulation and avoiding localized excessive or insufficient stimulation. The direction of the current is from the periphery to the center, mimicking the endogenous electric field, guiding cell migration toward the wound, and thus enhancing wound healing. The above dimensions are designed to meet the requirements of circular wounds with a diameter of 8-15 mm, and are used to implement the present invention and are not intended to limit the present invention. In other embodiments, the above dimensions can be adjusted accordingly based on actual needs, such as the size and shape of the wound.

[0072] Test Example 1

[0073] Test group: Example 1;

[0074] Test method:

[0075] (1) SEM scanning test method:

[0076] The fiber membrane prepared in Example 1 was cut into 1×1 cm squares and adhered to a metal tray using conductive adhesive. It was gold-sprayed for 30 min and photographed using a scanning electron microscope (SEM, JSM 7800F). The photographing parameters were: gold spraying 15 nm, voltage 2.7 kV, beam current 8, WD 9.6 mm, and photographing magnification 4000x.

[0077] (2) Water contact angle test method:

[0078] The fiber membrane prepared in Example 1 was cut into a rectangle of 20×10 mm, and then the cut fiber membrane was adhered to a homemade H-type glass slide so that the fiber membrane was parallel and its center was suspended on the water contact angle meter table. 5 μL RO water was dripped into the center of the fiber membrane with a needle, and the size of the water contact angle was analyzed and recorded using the equipped software.

[0079] (3) One-way drainage capacity test method:

[0080] First, the fiber membrane prepared in Example 1 was cut into a shape with the same outer diameter as the silicone gasket (inner diameter: 15 mm, outer diameter: 17 mm, thickness: 2 mm) and adhered to the silicone gasket. Then, 2 μL of simulated exudate containing 1% red ink was dripped into the hydrophobic layer and hydrophilic layer of the sample, respectively. The entire process of the water droplet contacting the fiber membrane and diffusing was recorded by video, and photos were taken to record the diffusion area on the hydrophilic and hydrophobic sides.

[0081] (4) Anti-gravity one-way drainage capacity test method:

[0082] First, the fiber membrane prepared in Example 1 was cut into a 20×10 mm rectangle and adhered to an H-type glass slide, which was then placed on a horizontal surface (Note: the fiber membrane must be stretched straight and suspended in the air) with the hydrophobic side facing down. A dispensing peristaltic pump was used to deliver 1 μL of simulated exudate containing fluorescent ink through a catheter to a No. 21 needle (fixed vertically upward). A video was used to record the entire process of the liquid being pumped out of the needle, contacting the hydrophobic layer of the fiber membrane, and being absorbed into the hydrophilic layer.

[0083] (5) Drug release test method:

[0084] The fiber membrane prepared in Example 1 was clamped tightly between two-way tubes. 10 mL of simulated exudate was added to each side, and a video was taken to record drug release. A certain amount of fiber membrane was placed in a centrifuge tube containing PBS. Samples were taken at specific time points, and the absorbance at 425 nm was measured using a UV spectrophotometer.

[0085] ;

[0086] in is the sampling volume (mL), is the drug concentration of the i-th sampling (μg / mL), is the total volume of the released liquid (mL), is the total drug loading (μg), Cn is the nth drug concentration, and n is 1, 2, 3,…, 9.

[0087] Test results:

[0088] Depend on Figure 4 and Figure 5 It can be seen that the prepared fiber membrane has a uniform diameter distribution and no beads. The water contact angle of the hydrophilic electrospun fiber membrane becomes close to 0° within 2s, showing superhydrophilicity. The water contact angle of the drug-loaded hydrophobic electrospun fiber membrane remains at around 110° within 1min, showing hydrophobicity. Figure 6 It can be seen that the double-layer fiber membrane achieves unidirectional liquid transport in about 26 seconds, and there is no reverse osmosis in the hydrophobic layer, indicating that the material has unidirectional liquid drainage capability. Figure 7 It can be seen that the liquid can be transported from the hydrophobic layer to the hydrophilic layer against gravity, indicating that the material has anti-gravity unidirectional drainage capability. Figure 8 and Figure 9 It can be seen that curcumin drug can be released from the hydrophobic side into the simulated exudate.

[0089] Test Example 2

[0090] Test groups: Example 1 and Comparative Examples 1 to 5;

[0091] Test method:

[0092] Air permeability test method:

[0093] Comparative Examples 1-5, respectively, consisted of a hydrophobic fiber membrane containing 10% curcumin, a commercial fiber membrane, a 3M membrane, a PDMS membrane, and a medical cloth tape membrane electrospun for 4 hours. The products of Example 1 and Comparative Examples 1-5 were subjected to a 21-day air permeability test. Each set of materials was sealed into the mouth of a centrifuge tube containing the same volume of deionized water. The water content of the centrifuge tube was weighed and recorded daily. The air permeability was calculated as follows:

[0094] Average water permeability = water mass loss / (cross-sectional area × time)

[0095] Test results:

[0096] from Figure 10 It can be seen that the material has similar air permeability as the open system.

[0097] Test Example 3

[0098] Test groups: Example 1, Example 2, Control group 1;

[0099] Test method:

[0100] Cytocompatibility testing methods:

[0101] The sterilized products of Example 1 and Example 2 were incubated in DMEM culture medium containing penicillin for 5 days to prepare material leaching solutions. Control group 1 was complete culture medium without adding material. Endothelial cells (EC cells) were seeded in 96-well plates at a density of 5000 cells / well. After culturing for 24 hours until the cells adhered to the wall, the original culture medium was replaced with the material leaching solution. After changing the medium every day and incubating for 3 or 5 days, the leaching solution was removed and 100 μL of pre-prepared complete culture medium containing 10% CCK-8 was added. After incubating in the dark for 1 hour, the absorbance value of the contents of the well plate at 450 was measured. The calculation formula of cell viability can be found in the CCK-8 reagent manual.

[0102] In addition, endothelial cells (EC cells) were seeded into 24-well plates and cultured for 24 hours until the cells adhered. The culture medium was then replaced with hydrogel extract. The medium was changed daily, and after 3 or 5 days of incubation, the extract medium was removed. The adherent cells in the wells were then stained with Calcein AM and propidium iodide (PI). The staining results for live cells (green fluorescence with Calcein) and dead cells (red fluorescence with propidium iodide) were observed using a fluorescence microscope.

[0103] Test results:

[0104] Depend on Figure 11 It is concluded that the double-layer fiber membrane and conductive hydrogel prepared by the present invention have good cell compatibility.

[0105] Test Example 4

[0106] Test groups: Comparative Example 6-Comparative Example 9, Example 2, wherein Comparative Example 6 is a hydrogel containing only polyvinyl alcohol, Comparative Example 7 is a hydrogel containing polyvinyl alcohol and tannic acid, Comparative Example 8 is a hydrogel containing polyvinyl alcohol, phytic acid, and tannic acid, and Comparative Example 9 is a hydrogel containing polyvinyl alcohol, phytic acid, tannic acid, and zinc chloride.

[0107] Test method:

[0108] (1) Small bulb lighting test method:

[0109] Each group of hydrogel samples was connected to two wires 2 cm apart, powered by a 3V battery, and formed a closed loop with a diode.

[0110] (2) Antibacterial performance test method:

[0111] A. Prepare bacterial culture medium: Dissolve 2.5g of tryptone, 1.25g of yeast extract, and 2.5g of sodium chloride in 250mL of deionized water and autoclave to obtain a liquid culture medium. For solid culture medium, add 3.75g of agarose per 250mL of liquid culture medium and autoclave to obtain a solid culture medium. Sterilize the bacterial workbench and plate with ultraviolet light for 30 minutes. Transfer the sterilized solid culture medium to the bacterial workbench and pour approximately 10mL of the medium onto the plate. Allow to cool before use.

[0112] B. Shake culture: Select single colonies of Staphylococcus aureus and Escherichia coli and place them in 10 mL of liquid culture medium. Shake and culture in a bacterial incubator for 7-8 hours.

[0113] C. Incubate bacteria and materials together: dilute the cultured bacterial suspension to a concentration of 10 5 The hydrogel material was added to a centrifuge tube, and 50 μL of the diluted bacterial suspension and 5 mL of liquid culture medium were added thereto and incubated for 8 h. In the control group 2, no hydrogel material was added.

[0114] D. Plate Spreading: Dilute the co-incubated bacterial suspension to an appropriate multiple. Place 10 μL of the diluted bacterial suspension on the surface of the solid culture medium. Pour five 3 mm glass beads into the culture dish and shake the dish crosswise for 5 minutes to evenly spread the bacterial suspension on the solid culture medium. Finally, place the dish in an incubator for 24 hours and observe the colony count. The formula for determining the bacterial killing rate of the hydrogel is as follows:

[0115] Bactericidal rate = (bacterial count in blank control group - bacterial count in material group) / bacterial count in blank control group * 100%.

[0116] Test results:

[0117] Depend on Figure 12 and Figure 13 It is concluded that the hydrogel material has good electrical conductivity and can make the small light bulb light up. Figure 14 It was concluded that the material had good antibacterial properties.

[0118] Test Example 5

[0119] Example 3 is an integrated device of a double-layer fiber membrane, a conductive silver paste layer, and a conductive hydrogel layer, while Comparative Example 10 is an integrated device of a 3M membrane and a conductive silver paste layer. The unidirectional effect test method is as follows: 10 μL of liquid containing 1% red ink is dripped onto the skin, and the side containing the conductive hydrogel is placed close to the skin to cover the liquid. The comparative example is to place the side containing the conductive silver paste close to the skin, uncover it after a period of time, and observe the liquid residue on the skin to judge the unidirectional drainage effect of the device. The effect diagram is as follows Figure 15 shown.

[0120] like Figure 16 As shown, the integrated device is connected to an external voltage of 3V, and the voltage at the end point of the conductive part is tested using a multimeter and is 2.840V.

[0121] like Figure 17 As shown, the integrated device was connected to a multimeter for impedance testing, and the test value was 0.2467 MΩ; the integrated device was connected to a signal generator for 30 minutes of electrical stimulation treatment.

[0122] Test Example 6

[0123] like Figure 18 As shown, after silver is made into a paste, the silver particles are connected by a resin or organic binder. If the resin system is relatively hard (such as epoxy resin), it will be brittle after curing and easily fall off in pieces when stretched. If a flexible resin system (such as polyurethane) is used, the elasticity of the silver paste can be improved, allowing the writing of stretchable silver paste on the fiber membrane. In addition, the fiber substrate is made of polyurethane, which improves the interfacial bonding of the stretchable conductive silver paste on the fiber membrane, but local cracks still exist during stretching. Therefore, a layer of conductive hydrogel is written on the stretchable silver paste area. The conductive electrode pairs encapsulated by the hydrogel can prevent the conductive ink from falling off and enhance the conductive electrode's ability to resist deformation. At the same time, the conductive hydrogel with antibacterial function also enhances the adhesion of the electrodes on the fiber dressing to the wound surface, giving the fiber-based dressing greater conformability and comfort. The antibacterial properties of the gel itself can also ensure that the patch effectively inhibits bacterial growth during long-term use.

[0124] Since the hydrogel substrate is polyvinyl alcohol, polyvinyl alcohol and phytic acid need to be mixed evenly and then repeatedly frozen and thawed to generate a large number of hydrogen bonds to form a hydrogel. If the integrated device with written gel is placed directly in the refrigerator, the moisture in the refrigerator will soak the double-layer fiber membrane and the one-way drainage function will be destroyed. Therefore, the written device needs to be placed in a dry and sealed box, then placed in the refrigerator to freeze, and then taken out and thawed at room temperature. In addition, the device with written gel cannot be placed in a vacuum drying bag and sealed, such as Figure 19 and Figure 20 As shown in the figure, under the action of vacuum, the water in the hydrogel will be squeezed out and diffused onto the double-layer fiber membrane, and the one-way drainage function will also be destroyed. Therefore, after the freeze-thaw cycle is completed, the device needs to be placed in a sealed box for the next step. Under the premise of not destroying the one-way drainage function, the conductive hydrogel is integrated on the electrode device through the optimized preparation process, such as Figure 21 As shown, the one-way drainage effect of the integrated dressing was tested on the wound of mice, which can ensure a dry and comfortable environment at the wound.

[0125] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are intended to be included therein.

[0126] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing a multifunctional wound patch combined with electrical stimulation therapy, characterized in that: The steps include: S1: Preparation of hydrophilic electrospun fiber membrane layer; Dissolving polyurethane and polyoxyethylene polyoxypropylene ether in a mass ratio of 4-5:1 in 10 mL of a binary organic solvent and stirring until completely dissolved to obtain an electrospinning solution of a hydrophilic electrospun fiber membrane with a concentration of 12 wt%-20 wt%, and subjecting the obtained electrospinning solution of the hydrophilic electrospun fiber membrane to an electrospinning treatment to obtain a hydrophilic electrospun fiber membrane layer; S2: Continuously performing electrospinning on the hydrophilic electrospun fiber membrane layer to obtain a drug-loaded hydrophobic electrospun fiber membrane layer; Dissolve polyurethane and curcumin in 10 mL of a binary organic solvent and stir at room temperature until completely dissolved to obtain an electrospinning solution of a drug-loaded hydrophobic electrospun fiber membrane with a concentration of 12 wt%-20 wt%, wherein the mass fraction of curcumin in the solute polyurethane is 5%-15%, and continuously electrospinning is performed on the hydrophilic electrospun fiber membrane layer to obtain a drug-loaded hydrophobic electrospun fiber membrane layer; S3: Directly write a serpentine concentric circle conductive ink layer on the drug-loaded hydrophobic electrospun fiber membrane layer to form a serpentine concentric circle conductive electrode pair, one of which is a ring-shaped serpentine electrode and the other is a central circle electrode. The ends of the two electrodes are drawn with corresponding sized square conductive ports; Conductive silver ink is used as the conductive material, the writing speed is 10-30 mm / min, and the air pressure is 2-5Kg / cm 2 ; S4: A conductive hydrogel layer is written on the serpentine concentric circle conductive ink layer. The surface of the hydrophobic fiber layer directly contacts the wound side, which allows the wound exudate to be discharged in a directional manner and prevents reverse leakage of the exudate. The conductive hydrogel material is composed of polyvinyl alcohol, phytic acid, tannic acid, zinc chloride and glycerol; the writing speed is 1-5mm / min, and the air pressure is 3-5Kg / cm 2 .

2. The method for preparing a multifunctional wound patch combined with electrical stimulation therapy according to claim 1, characterized in that: The electrospinning process parameters in steps S1 and S2 are: receiving distance of 10-15 cm, voltage of 15-20 kV, pushing speed of 0.6-1.2 mL / h, temperature of 20-30°C, humidity below 50%, drum speed of 100-200 r / min, and spinning time of 1-5 h.

3. The method for preparing a multifunctional wound patch combined with electrical stimulation therapy according to claim 1, characterized in that: The binary organic solvent in steps S1 and S2 is an organic solution composed of N,N-dimethylformamide and dichloromethane in a volume ratio of 1-9:

1.

4. The method for preparing a multifunctional wound patch combined with electrical stimulation therapy according to claim 1, characterized in that: After the writing is completed in step S3, the fiber film is placed in a blast drying oven and dried at 60° C. for 1-2 hours to evaporate the organic solvent in the conductive silver paste.

5. The method for preparing a multifunctional wound patch combined with electrical stimulation therapy according to claim 1, characterized in that: In the conductive hydrogel material of step S4, the concentration of polyvinyl alcohol is 8 wt %-12 wt %, the mass ratio of phytic acid to polyvinyl alcohol is 0.5-1:1, and the mass ratio of tannic acid to polyvinyl alcohol is 0.05-0.1:

1.

6. A multifunctional wound patch combined with electrical stimulation therapy prepared by the method according to any one of claims 1 to 5, characterized in that: The multifunctional wound patch comprises a double-layer electrospun fiber membrane, a conductive ink layer and a conductive hydrogel layer, wherein the double-layer electrospun fiber membrane comprises a hydrophilic electrospun fiber membrane layer (1) and a drug-loaded hydrophobic electrospun fiber membrane layer (2), and the multifunctional wound patch comprises, from top to bottom, a hydrophilic electrospun fiber membrane layer (1), a drug-loaded hydrophobic electrospun fiber membrane layer (2), a conductive ink layer (3) and a conductive hydrogel layer (4), and the adjacent two layers are tightly combined.

7. The multifunctional wound patch combined with electrical stimulation therapy according to claim 6, characterized in that: The thickness of the hydrophilic electrospun fiber membrane layer (1) is 25-40 μm, and the thickness of the drug-loaded hydrophobic electrospun fiber membrane layer (2) is 20-35 μm.

8. The multifunctional wound patch combined with electrical stimulation therapy according to claim 6, characterized in that: The conductive ink layer (3) is a serpentine concentric circle conductive ink layer, the diameter of the center circle is 2 mm, the radius from the center of the center circle to the outermost side of the serpentine ring is 10 mm, the radius from the center of the center circle to the innermost side of the serpentine ring is 8 mm, the line width is 1 mm, and the end interface is 4 mm long and 3 mm wide.

9. The multifunctional wound patch combined with electrical stimulation therapy according to claim 6, characterized in that: The conductive hydrogel layer (4) has a central diameter of 4 mm, a line width of 2 mm, and a thickness of 0.1 mm.

Images