A medical dressing, preparation method and application

Abstract

A medical dressing, a preparation method and an application, belonging to the field of functional composite materials. The dressing is prepared by blending liquid metal, multifunctional additives and polyurethane; taking the weight of polyurethane as 100 weight fractions, the amount of multifunctional additives is 10 - 55 weight parts, the liquid metal is 800 - 1500 weight parts, the polyurethane is a urea-containing polyurea polyurethane, the liquid metal is a gallium-indium alloy with a melting point of 3°C - 30°C, and the multifunctional additive is glutathione and its derivatives. The medical dressing of the present invention has excellent biocompatibility, has self-healing and wound healing promoting functions, can be widely used in the field of medical materials, and plays a positive role in wound repair with the assistance of electrical stimulation, and can be used for wound dressings or medical materials for promoting tissue regeneration.

Description

Technical Field

[0001] The present invention belongs to the field of functional composite materials, and particularly relates to a medical dressing, a preparation method and an application thereof. Background Art

[0002] The skin is the largest organ of the human body, which not only protects the internal tissues and organs of the human body from the invasion of external harmful factors, but also plays a role in sensing and metabolism. However, due to reasons such as diabetes, aging, and burns, skin or tissue injuries are difficult to heal for a long time, which not only causes inconvenience in daily life, reduces immunity, but even endangers life. Therefore, the research on promoting wound healing is an important topic for life science and improving the quality of human life.

[0003] Applying electrical stimulation (ES) to the wound site of a patient can promote cell proliferation and differentiation, thereby promoting tissue repair. Researchers have detected that skin injury will cause an endogenous current at the wound, which helps to accelerate the migration of key cells and plays a positive role in wound healing. On this basis, simulating and enhancing the wound potential will contribute to tissue repair in the following aspects: (1) facilitating DNA and collagen synthesis; (2) migration of wound healing-related cells; (3) antibacterial effects in vitro and in vivo. Therefore, promoting wound healing by applying external electrical stimulation has great application prospects. However, traditional electrode materials are too rigid and have poor plasticity, resulting in problems of incompatibility with the skin interface and difficulty in achieving good skin compliance; moreover, traditional electrode materials have poor self-healing properties and are difficult to meet the complex requirements of daily use; at the same time, the power supply parts of traditional electrode materials are too concentrated, making it difficult to form a stable and uniform electrical stimulation, which affects the treatment effect and the use experience. Using a flexible conductive dressing instead of a traditional rigid electrode is an effective method to solve the above problems. The paper Chemical Engineering Journal 406(2021)126741 prepared a conductive foam dressing by dispersing silver nanowires in porous polyurethane. This dressing can uniformly and effectively promote wound healing under external electrical stimulation, but the silver nanowire conductive filler and polyurethane foam used in this dressing do not have self-healing properties.

[0004] Liquid metal (LM) is a new type of alloy with good biocompatibility and electrical conductivity. It has fluidity similar to that of a liquid under near-ambient conditions, high deformability and reworkability, which provides the possibility for it to be used as a conductive filler to achieve skin compliance and self-healing of wound dressings. The paper Adv. Funct. Mater. 2022, 32, 2200444 encapsulated liquid metal into polydimethylsiloxane (PDMS) blended with polyethylene glycol (PEG) to prepare epidermal electronic devices, conducted physiological detection experiments and significantly promoted wound healing through external electrical stimulation. However, in this study, the liquid metal was encapsulated into the matrix material with a fixed thickness and shape, making it difficult to achieve uniform electrical stimulation for wounds of different shapes. And due to the liquid state of liquid metal at room temperature, this preparation method is prone to the problem of a large amount of liquid metal leakage after the dressing is damaged, causing inconvenience in use. The paper ACS Nano 2019, 13, 9122 - 9130 synthesized a liquid metal composite hydrogel for stretchable electronic products by ultraviolet radiation method. This material can achieve circuit reconstruction through friction induction. However, due to the poor compatibility between liquid metal and the matrix, the composite hydrogel prepared in this study shows low mechanical properties. Currently, there is no relevant report on a self-healing type wound healing promoting dressing based on liquid metal. Therefore, there is an urgent need to develop a medical material with good self-healing property, skin compliance, biocompatibility, and uniform electrical response that can promote wound healing. Summary of the Invention

[0005] To solve the problems in the prior art, the present invention provides a medical dressing, a preparation method and an application thereof. The composite material obtained by the present invention has excellent self-healing property, uniform electrical conductivity, good biocompatibility, is safe and non-toxic, and can significantly promote the repair of the wound surface through the auxiliary effect of external electrical stimulation.

[0006] Technical solution of the present invention:

[0007] A medical dressing, which is prepared by blending liquid metal, a multifunctional additive and polyurethane; the polyurethane is a polyurea polyurethane containing urea groups; the liquid metal is one or more mixtures of gallium-indium alloys with a melting point of 3 - 30 °C; the multifunctional additive is one or more mixtures of glutathione and its derivatives.

[0008] Furthermore, taking the weight of polyurea polyurethane as 100 weight fractions, the addition amount of each substance is 10 - 55 weight parts for the multifunctional additive and 800 - 1500 weight parts for the liquid metal.

[0009] Furthermore, in the medical dressing, the polyurea polyurethane has self-healing property, the liquid metal has a structure remodeling function, the multifunctional additive improves the system compatibility and has the effect of promoting wound surface healing.

[0010] Furthermore, the polyurea polyurethane is prepared by solution reaction from raw materials including the following components: taking isocyanate as 100 parts by weight, polyol mixture as 50 - 500 parts by weight, chain extender as 10 - 50 parts by weight, catalyst as 1 - 8 parts by weight, and solvent as 500 - 1000 parts by weight.

[0011] Furthermore, the isocyanate is one or a mixture of two or more of isophorone diisocyanate, dicyclohexylmethane - 4,4'-diisocyanate, and diphenylmethane diisocyanate; the polyol mixture is a mixture of two or more of polyether diol 200 - 3000 or polyester diol 200 - 2000; the chain extender is one of isophthaloyl hydrazide, maleic dihydrazide, succinic dihydrazide, and furan - 2,5 - dicarboxylic dihydrazide;; the catalyst is an organotin catalyst; the solvent is one of dimethylformamide and dimethylacetamide.

[0012] Furthermore, the preparation process of the polyurea polyurethane is as follows: the polyol mixture, catalyst, and isocyanate are dissolved in the solvent in proportion, heated to 60°C - 80°C, and stirred and reacted for 2 - 3 h; after cooling to room temperature, the chain extender is added, and stirred and reacted at room temperature for 2 h - 4 h; after removing the solvent, it is stored dry or dissolved in an ethanol solution for standby.

[0013] A preparation method of a medical dressing includes the following steps:

[0014] Disperse liquid metal in an aqueous alcohol solution in which a multifunctional additive has been dissolved by ultrasound for 10 - 120 min; add the ethanol solution of polyurea polyurethane according to the ratio and ultrasound for 1 - 5 min; pour or scrape the dispersion liquid, and obtain the dressing after drying.

[0015] An application of a medical dressing, the medical dressing has excellent biocompatibility, has self - repairing and wound - healing promoting functions, and can be widely applied in the field of medical materials.

[0016] Furthermore, with the assistance of electrical stimulation, it plays a positive role in wound repair and can be used for wound dressings or medical materials for promoting tissue regeneration.

[0017] The present invention includes the following beneficial effects:

[0018] (1) The dressing of the present invention has excellent biocompatibility, self - reparability, is safe and non - toxic, and can promote rapid wound healing at the same time.

[0019] (2) The multifunctional additive of the present invention not only facilitates the good dispersion of liquid metal in the polymer matrix, greatly improves the electrical conductivity uniformity, but also helps to improve skin immunity, thereby assisting in the repair of the wound skin.

[0020] (3) In the present invention, the polyurea polyurethane structure containing urea groups contains multiple hydrogen bonds, endowing the matrix material with excellent self-healing properties. In synergistic action with the multifunctional additive, it further improves the stable dispersion of the liquid metal.

[0021] (4) The liquid metal in the present invention has a low melting point and strong deformation ability, which is conducive to realizing structure reshaping; it has excellent biocompatibility. Even in the case of high filling and large thickness, the dressing still has good skin compliance, plasticity and self-healing properties, which helps the future development of electrostimulation to promote tissue healing to be more personalized and differentiated. Description of the Drawings

[0022] Figure 1 It is the transmission electron microscope photograph of the liquid metal-glutathione dispersion in Example 1;

[0023] Figure 2 It is the scanning electron microscope photograph of the cross-section of the dressing in Example 1;

[0024] Figure 3 It is the live-dead cell staining photograph of the dressing in Example 1 at 24 hours and 48 hours. Specific Implementation Methods

[0025] Except for special regulations otherwise, the reagents used in the embodiments of the present invention can be obtained by commercial purchase.

[0026] It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Except for the raw materials used in the embodiments of the present invention, raw material components with the same functional groups as those in the raw materials used in the embodiments or containing the same structural units involved in the present invention and using equivalent replacement should be included in the protection scope of the present invention. The present invention will be further described below with specific embodiments.

[0027] The present invention provides the attached drawings of the detection results of some embodiments. The same detection methods are used for other embodiments and comparative examples. Those skilled in the art can directly and unambiguously determine the content of the embodiments of the present invention through the detection methods provided by the present invention.

[0028] The external electrostimulation method adopted by the present invention is to connect a 3.6V button battery to the wound healing dressing

[0029] The present invention will be further described below with reference to the embodiments.

[0030] Example 1

[0031] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of isophorone diisocyanate, 280 parts of polyethylene glycol 2000, 20 parts of polyethylene glycol 400, and 5 parts of dibutyltin dilaurate. Place them in a three-necked flask, add 600 parts of N,N-dimethylformamide to dissolve, heat up to 60 °C, and stir and react for 3 h; stop heating, and after natural cooling to room temperature, add 40 parts of isophthalic dihydrazide, and stir and react at room temperature for 2 h; after drying N,N-dimethylformamide, polyurea polyurethane 1 is obtained.

[0032] (2) Preparation of medical dressing: Use ultrasonic crushing to disperse 1500 parts by weight of gallium-indium alloy (melting point is 3 °C) in 20 ml of an alcohol aqueous solution in which 55 parts of glutathione have been dissolved, and ultrasonicate for 60 min; add the polyurethane-ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonicate for 1 min; pour the dispersion into a mold, and after drying, a self-healing dressing 1 is obtained. Prepare test specimens, vertically cut them in the middle, splice them again in a 35 °C air blast dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. Additionally, assist in fixing a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0033] Example 2

[0034] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of dicyclohexylmethane-4,4'-diisocyanate, 280 parts of polyethylene glycol 2000, 20 parts of polyethylene glycol 400, and 3 parts of dibutyltin dilaurate. Place them in a three-necked flask, add 800 parts of N,N-dimethylacetamide to dissolve, heat up to 75 °C, and stir and react for 2.5 h; stop heating, and after natural cooling to room temperature, add 40 parts of maleic dihydrazide, and stir and react at room temperature for 3 h; after drying N,N-dimethylacetamide, polyurea polyurethane 2 is obtained.

[0035] (2) Preparation of medical dressing: Use ultrasonic crushing to disperse 1200 parts by weight of gallium-indium alloy (melting point is 11 °C) in 20 ml of an alcohol aqueous solution in which 45 parts of glutathione have been dissolved, and ultrasonicate for 60 min; add the polyurethane-ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonicate for 2 min; pour the dispersion into a mold, and after drying, a self-healing dressing 2 is obtained. Prepare test specimens, vertically cut them in the middle, splice them again in a 35 °C air blast dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. Additionally, assist in fixing a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0036] Example 3

[0037] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of isophorone diisocyanate, 200 parts of polyethylene glycol 2000, 40 parts of polyethylene glycol 400, and 2 parts of dibutyltin dilaurate. Place them in a three-necked flask, add 500 parts of N,N-dimethylformamide to dissolve, heat up to 80 °C, and stir and react for 2 h; stop heating, and after naturally cooling to room temperature, add 30 parts of isophthaloyl hydrazide, and stir and react at room temperature for 3 h; after drying N,N-dimethylformamide, polyurea polyurethane 3 is obtained.

[0038] (2) Preparation of self-healing dressing: Use ultrasonic crushing to disperse 1200 parts by weight of gallium-indium alloy (melting point is 11 °C) in 20 ml of an alcohol-water solution in which 40 parts of glutathione have been dissolved, and ultrasonic for 100 min; add the polyurethane-ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonic for 1 min; pour the dispersion into a mold, and after drying, self-healing dressing 3 is obtained. Prepare test specimens, cut them vertically in the middle, splice them again in a 35 °C air-blowing dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. In addition, assist in fixing a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0039] Example 4

[0040] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of diphenylmethane diisocyanate, 200 parts of polyethylene glycol 2000, 40 parts of polyethylene glycol 400, and 1 part of dibutyltin dilaurate. Place them in a three-necked flask, add 600 parts of N,N-dimethylacetamide to dissolve, heat up to 80 °C, and stir and react for 3 h; stop heating, and after naturally cooling to room temperature, add 30 parts of succinyl hydrazide, and stir and react at room temperature for 4 h; after drying N,N-dimethylacetamide, polyurea polyurethane 4 is obtained.

[0041] (2) Preparation of self-healing dressing: Use ultrasonic crushing to disperse 1000 parts by weight of gallium-indium alloy (melting point is 11 °C) in 20 ml of an alcohol-water solution in which 40 parts of glutathione have been dissolved, and ultrasonic for 100 min; add the polyurethane-ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonic for 1 min; pour the dispersion into a mold, and after drying, self-healing dressing 4 is obtained. Prepare test specimens, cut them vertically in the middle, splice them again in a 35 °C air-blowing dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. In addition, assist in fixing a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0042] Example 5

[0043] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of dicyclohexylmethane - 4,4'-diisocyanate, 120 parts of polyethylene glycol 2000, 57 parts of polyethylene glycol 400, and 2 parts of dibutyltin dilaurate. Add 500 parts of N,N - dimethylformamide to a three - necked flask for dissolution, heat up to 75 °C, and stir - react for 2.5 h; stop heating, and after natural cooling to room temperature, add 40 parts of isophthalic dihydrazide, and stir - react at room temperature for 3 h; after drying N,N - dimethylformamide, polyurea polyurethane 5 is obtained.

[0044] (2) Preparation of self - healing dressing: Use ultrasonic comminution to disperse 800 parts by weight of gallium - indium alloy (melting point 16 °C) in 20 ml of an alcohol - aqueous solution in which 30 parts of glutathione have been dissolved, and ultrasonicate for 80 min; add the polyurethane - ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonicate for 3 min; pour the dispersion into a mold, and after drying, self - healing dressing 5 is obtained. Prepare test specimens, cut them vertically in the middle, splice them again in a 35 °C air - blast dryer, and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1 - 2. Additionally, fix a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 5.

[0045] Example 6

[0046] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of dicyclohexylmethane - 4,4'-diisocyanate, 120 parts of polyethylene glycol 2000, 30 parts of polyethylene glycol 400, and 2 parts of dibutyltin dilaurate. Add 200 parts of N,N - dimethylformamide to a three - necked flask for dissolution, heat up to 70 °C, and stir - react for 3 h; stop heating, and after natural cooling to room temperature, add 50 parts of furan - 2,5 - dicarboxylic dihydrazide, and stir - react at room temperature for 3 h; after drying N,N - dimethylformamide, polyurea polyurethane 6 is obtained.

[0047] (2) Preparation of self - healing dressing: Use ultrasonic comminution to disperse 1000 parts by weight of gallium - indium alloy (melting point 30 °C) in 20 ml of an alcohol - aqueous solution in which 30 parts of glutathione have been dissolved, and ultrasonicate for 120 min; add the polyurethane - ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonicate for 5 min; pour the dispersion into a mold, and after drying, self - healing dressing 6 is obtained. Prepare test specimens, cut them vertically in the middle, splice them again in a 35 °C air - blast dryer, and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1 - 2. Additionally, fix a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0048] Example 7

[0049] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of dicyclohexylmethane - 4,4'-diisocyanate, 20 parts of polycarbonate diol 2000 (PCDL 2000), 70 parts of polyethylene glycol 400, and 2 parts of dibutyltin dilaurate. Place them in a three - necked flask, add 500 parts of N,N - dimethylformamide to dissolve, heat up to 70 °C, and stir for 3 h; stop heating, and after natural cooling to room temperature, add 40 parts of isophthalic dihydrazide, and stir at room temperature for 3 h; after drying N,N - dimethylformamide, polyurea polyurethane 7 is obtained.

[0050] (2) Preparation of self - healing dressing: Use ultrasonic crushing to disperse 1000 parts by weight of gallium - indium alloy (melting point is 11 °C) in 20 ml of an alcohol - aqueous solution in which 15 parts of S - acetyl - L - glutathione have been dissolved, and ultrasonicate for 40 min; add the polyurethane - ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonicate for 2 min; pour the dispersion into a mold, and after drying, self - healing dressing 7 is obtained. Prepare test specimens, cut them vertically in the middle, splice them again in a 35 °C air - blast dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1 - 2. Additionally, assist in fixing a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0051] Example 8

[0052] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of dicyclohexylmethane - 4,4'-diisocyanate, 140 parts of polycarbonate diol 2000 (PCDL 2000), 50 parts of polyethylene glycol 400, and 2 parts of dibutyltin dilaurate. Place them in a three - necked flask, add 1000 parts of N,N - dimethylformamide to dissolve, heat up to 70 °C, and stir for 3 h; stop heating, and after natural cooling to room temperature, add 10 parts of isophthalic dihydrazide, and stir at room temperature for 2 h; after drying N,N - dimethylformamide, polyurea polyurethane 8 is obtained.

[0053] (2) Preparation of self - healing dressing: Use ultrasonic crushing to disperse 1000 parts by weight of gallium - indium alloy (melting point is 11 °C) in 20 ml of an alcohol - aqueous solution in which 10 parts of glutathione have been dissolved, and ultrasonicate for 40 min; add the polyurethane - ethanol (100 parts by weight) solution prepared in step (1) according to the ratio, and ultrasonicate for 2 min; pour the dispersion into a mold, and after drying, self - healing dressing 8 is obtained. Prepare test specimens, cut them vertically in the middle, splice them again in a 35 °C air - blast dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1 - 2. Additionally, assist in fixing a 3.6 V button battery at the mouse wound to apply electrical stimulation to promote healing, and its wound healing situation is shown in Table 3.

[0054] Example 9

[0055] (1) Preparation of polyurea polyurethane: Weigh 100 parts by weight of isophorone diisocyanate, 360 parts of polyethylene glycol 1000, 8 parts of polyethylene glycol 400, and 8 parts of dibutyltin dilaurate. Add them to a three-necked flask and dissolve in 1000 parts of N,N-dimethylformamide. Heat to 60 °C and stir for 3 h. Stop heating and let it cool naturally to room temperature. Then add 40 parts of isophthaloyl hydrazide and stir at room temperature for 3 h. After drying N,N-dimethylformamide, polyurea polyurethane 9 is obtained.

[0056] (2) Preparation of self-healing dressing: Disperse 1000 parts by weight of gallium-indium alloy (melting point 11 °C) in 20 ml of an aqueous alcohol solution in which 40 parts of S-acetyl-L-glutathione has been dissolved by ultrasonic crushing for 40 min. Add the polyurethane-ethanol (100 parts by weight) solution prepared in step (1) according to the ratio and ultrasonicate for 5 min. Pour the dispersion into a mold and dry to obtain self-healing dressing 9. Prepare test specimens, cut them vertically in the middle, rejoin them in a 35 °C forced-air dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. Additionally, fix a 3.6 V button battery to the mouse wound to apply electrical stimulation to promote healing, and the wound healing situation is shown in Table 3.

[0057] Comparative Example 1

[0058] Replace isophthaloyl hydrazide in Example 1(1) with isophthalamide, keep other conditions in Example 1 unchanged, and prepare polyurethane and dressing. Prepare test specimens, cut them vertically in the middle, rejoin them in a 35 °C forced-air dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. Additionally, fix a 3.6 V button battery to the mouse wound to apply electrical stimulation to promote healing, and the wound healing situation is shown in Table 3.

[0059] Comparative Example 2

[0060] Keep other conditions in Example 1(1) unchanged. In step (2), do not add glutathione, directly ultrasonicate the liquid metal in the polyurethane ethanol solution for 62 min, pour the dispersion into a mold and dry to obtain the product. Prepare test specimens, cut them vertically in the middle, rejoin them in a 35 °C forced-air dryer and test the mechanical strength recovery and conductivity recovery of the dressing at different times, as shown in Table 1-2. Additionally, fix a 3.6 V button battery to the mouse wound to apply electrical stimulation to promote healing, and the wound healing situation is shown in Table 3.

[0061] Comparative Example 3

[0062] Replace isophthalohydrazide in Example 1(1) with isophthalamide, and in step (2), do not add glutathione. Directly ultrasonicate the liquid metal in the polyurethane ethanol solution for 62 min, pour the dispersion into a mold, and dry to obtain the product. Prepare test specimens, vertically cut them in the middle, splice them again in a 35 °C air dryer and test the recovery of the mechanical strength of the dressing at different times, as well as the recovery of the conductivity, as shown in Table 1-2. Additionally, fix a 3.6 V button battery to the mouse wound to apply electrical stimulation to promote healing, and the wound healing situation is shown in Table 3.

[0063] Table 1 Mechanical strength recovery rate

[0064]

[0065]

[0066] Table 2 Conductivity recovery rate

[0067] 30 min 1h 2h 3h 4h 5h 6h Example 1 100％ - - - - - - Example 2 100％ - - - - - - Example 3 100％ - - - - - - Example 4 100％ - - - - - - Example 5 96％ 100％ - - - - - Example 6 96％ 100％ - - - - - Example 7 90％ 100％ - - - - - Example 8 88％ 100％ - - - - - Example 9 100％ - - - - - - Comparative Example 1 0 0 0 0 0 0 0 Comparative Example 2 40％ 62％ 83％ 83％ 83％ 83％ 83％ Comparative Example 3 0 0 0 0 0 0 0

[0068] Table 3 Wound healing rate

[0069]

[0070]

[0071] Comparing Table 1 and Table 2, under the condition of 35 °C, the mechanical properties of the dressing in the example can be well recovered within 4-5 h, and its conductivity can be instantly recovered. However, for Comparative Example 1 and Comparative Example 3 where no urea bond is introduced into the structure, both the mechanical properties and electrical properties cannot be recovered. In Comparative Example 2, due to the lack of multifunctional additives, the dispersion of the internal gallium-indium alloy is poor, the self-healing rate of its mechanical properties decreases, and the electrical properties are difficult to fully recover.

[0072] Comparing with Table 3, due to the poor self-healing ability of the dressings in Comparative Example 1 and 3, the dressings cannot maintain uniform and stable electrical stimulation through self-healing during the treatment process, and the wound healing speed is slower than that of the example. At the same time, for Comparative Example 2 without adding multifunctional additives, the wound healing speed is also slower, which proves that the addition of additives is beneficial to achieving better healing effects by promoting dispersion and enhancing skin immunity.

[0073] Figure 1 It can be seen from the transmission electron microscope that the multifunctional additive (glutathione) in Example 1 is coated on the surface of the liquid metal, proving that it has good interaction with the liquid metal and can promote its good dispersion. Figure 2 The cross-sectional scanning electron microscope photo further proves that the liquid metal is uniformly dispersed in the dressing without obvious agglomeration phenomenon, and a uniform and stable electrical response can be formed. Figure 3In vitro live / dead cell assay (CalceinAM staining for live cells and PI staining for dead cells). A large number of green cells were stained with CalceinAM, and very few red cells were stained with PI, indicating that fibroblasts proliferated in the dressing extract did not show large-scale death within 48 h, and the cell morphology remained good, proving that the dressing in Example 1 had good biocompatibility and could be applied in medical fields.

[0074] The composite dressing provided by the present invention can promote wound healing. At the same time, it has good flexibility, self-repairability, biocompatibility and plasticity, overcomes the problem that traditional dressings are difficult to self-repair, has the potential to achieve more extensive, convenient and effective medical applications, and has good development prospects.

[0075] Those of ordinary skill in the art should understand that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A medical dressing, characterized in that: The dressing is prepared by blending liquid metal, multifunctional additives and polyurethane; the polyurethane is a urea-containing polyurea polyurethane; the liquid metal is one or more mixtures of gallium-indium alloys with a melting point of 3°C - 30°C; the multifunctional additives are one or more mixtures of glutathione and its derivatives.

2. The medical dressing according to claim 1, characterized in that: Taking the weight of the polyurea polyurethane as 100 weight fractions, the addition amount of each substance is 10 - 55 weight parts for the multifunctional additives and 800 - 1500 weight parts for the liquid metal.

3. A medical dressing according to claim 1, characterized in that, In the medical dressing, the polyurea polyurethane has self-healing properties, the liquid metal has a structure remodeling function, the multifunctional additives improve the system compatibility, and have the effect of promoting wound healing.

4. A medical dressing according to claim 1, wherein The polyurea polyurethane is prepared by solution reaction from raw materials including the following components: taking isocyanate as 100 weight parts, polyol mixture as 50 - 500 weight parts, chain extender as 10 - 50 weight parts, catalyst as 1 - 8 weight parts, and solvent as 500 - 1000 weight parts.

5. The medical dressing according to claim 4, characterized in that, The isocyanate is one or more mixtures of isophorone diisocyanate, dicyclohexylmethane - 4,4'-diisocyanate, diphenylmethane diisocyanate.

6. The medical dressing according to claim 4, characterized in that, The polyol mixture is a mixture of two or more of polyether diol 200 - 3000 or polyester diol 200 - 2000; the chain extender is one of isophthaloyl hydrazide, maleic dihydrazide, succinic dihydrazide, furan - 2,5 - dicarboxylic hydrazide; the catalyst is an organotin catalyst; the solvent is one of dimethylformamide, dimethylacetamide.

7. The medical dressing according to claim 4, wherein The preparation process of the polyurea polyurethane is as follows: the polyol mixture, catalyst, and isocyanate are dissolved in the solvent in proportion, heated to 60°C - 80°C, and stirred and reacted for 2 - 3 h; after cooling to room temperature, the chain extender is added, and stirred and reacted at room temperature for 2 h - 4 h; after removing the solvent, it is stored dry or dissolved in an ethanol solution for standby.

8. A method for preparing a medical dressing according to any one of claims 1-7, characterized in that, Including the following steps: The liquid metal is dispersed in an aqueous alcohol solution in which the multifunctional additives have been dissolved by ultrasonic treatment for 10 - 120 min; the ethanol solution of polyurea polyurethane is added according to the ratio, and ultrasonic treatment is carried out for 1 - 5 min; the dispersion is poured or scraped, and the dressing is obtained after drying.

9. Use of a medical dressing according to any one of claims 1-7 or a medical dressing obtained by the preparation method according to claim 8, characterized in that, The medical dressing has excellent biocompatibility, has self-healing and wound healing promoting functions, and can be widely used in the field of preparing medical materials.

10. The application of a medical dressing as claimed in claim 9, wherein, With the assistance of electrical stimulation, it plays a positive role in wound repair and can be used to prepare wound dressings or medical materials for promoting tissue regeneration.

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