A self-directed dressing and method of making the same

Abstract

The application discloses a self-guiding dressing and a preparation method thereof. The self-guiding dressing comprises a liquid storage layer and a liquid guiding layer, wherein the liquid storage layer and the liquid guiding layer comprise continuous hydrogels, the liquid guiding layer further comprises oil gel particles distributed in the hydrogels, and the hydrogels between adjacent oil gel particles form hydrophilic channels, so that unidirectional liquid guiding is realized by using the hydrophilic channels, backflow of the absorbed liquid is inhibited, wound exudate can be absorbed into the interior of the hydrogels along the hydrophilic channels between the oil gel particles by capillary force, the oil gel particles arranged on the surface of the liquid guiding layer prevent the absorbed exudate from flowing back to the wound surface and exchange, and adhesion between the dressing and the wound is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wound dressing, in particular to a self-guiding dressing and a preparation method thereof. BACKGROUND

[0002] Skin is the outermost barrier of the human body, and its main function is to protect the underlying muscles, bones, ligaments and internal organs from external biological, chemical, mechanical and physical damage. When the skin is damaged due to factors such as cuts, burns, surgical incisions or diabetes, its structure and function must be re-established to ensure the normal operation of skin function as soon as possible. In order to achieve this purpose, the healing of the wound begins. This process almost occurs immediately after the skin is injured to avoid bacterial contamination. Abnormal healing of the wound often leads to bacterial infection, which causes pathological changes in the human body, and in severe cases, permanent disability or even death.

[0003] Hydrogel dressings are usually water-insoluble hydrophilic polyurethane polymers composed of natural or synthetic polymers. These three-dimensional polymer gels have a hydrophilic porous structure and have high water absorption and water retention capacity. Hydrogels have unique characteristics of high water content (up to 99.5%), non-adhesion, ductility and biological compatibility similar to living tissues. In addition, hydrogels exhibit swelling and reversible deswelling properties in aqueous solutions, so they have a wide range of applications in regenerative medicine, drug delivery, and the focus of this review, wound healing. Hydrogel dressings can create a microenvironment with appropriate moisture on the wound surface, have very high plasticity, and will not cause adhesion to the skin during use because they have high water content, thereby providing a cooling and soothing effect on the wound surface, thereby reducing the pain of dressing change. In addition, the limited adhesion of hydrogels means that they can be easily removed without causing further trauma to the healing tissue.

[0004] In 2007, D. McColl's research group at the University of Buckinghamshire Chilterns University College characterized the moisture profile, impedance and dehydration rate of the wound, and studied the effect of foam dressings with different compositions on the moisture of the wound. They found that excessive infiltration would inhibit wound healing, and this study attracted attention to the control of the moisture of the wound surface.

[0005] Existing medical hydrogel dressings are prone to cause skin immersion and decrease the strength of skin tissue when treating wounds, because the moisture of the wound environment is too large or the gel itself continuously absorbs and exchanges with the exudate on the wound surface. SUMMARY

[0006] Therefore, the self-directed drainage dressing is provided to utilize the capillary force to unidirectionally guide the liquid, inhibit the backflow of the absorbed liquid, and prevent the absorbed exudate from flowing back to the wound surface and from adhering to the wound.

[0007] The self-directed drainage dressing is also provided to provide a preparation method of the self-directed drainage dressing, which is simple and fast.

[0008] To achieve the above object, the technical scheme of the present application is as follows:

[0009] The self-directed drainage dressing comprises a liquid storage layer and a liquid guiding layer connected to one side of the liquid storage layer; the liquid storage layer and the liquid guiding layer comprise a hydrogel connected in sequence; and the liquid guiding layer further comprises oil gel particles distributed in the hydrogel. The liquid guiding layer is a wound contact layer, the hydrogel between the adjacent oil gel particles in the liquid guiding layer forms a hydrophilic channel, the capillary force is utilized to unidirectionally guide the liquid, the backflow of the absorbed liquid is inhibited, the outermost oil gel particles in the liquid guiding layer are exposed on the surface of the liquid guiding layer, and the oil gel particles arranged on the surface of the liquid guiding layer prevent the absorbed exudate from flowing back to the wound surface and from adhering to the wound.

[0010] In a preferred embodiment, the liquid guiding layer has a non-uniform composition in the thickness section, and the specific composition mainly includes: (1) the average particle size of the oil gel particles existing in the surface region of the hydrogel is greater than the average particle size of the oil gel particles existing in the internal region of the hydrogel, and the average gap distance of the oil gel particles existing in the surface region of the hydrogel is greater than the average gap distance of the oil gel particles existing in the internal region of the hydrogel; (2) the average particle size of the oil gel particles existing in the surface region of the hydrogel is greater than the average particle size of the oil gel particles existing in the internal region of the hydrogel, and the average gap distance of the oil gel particles existing in the surface region of the hydrogel is less than the average gap distance of the oil gel particles existing in the internal region of the hydrogel; (3) the average particle size of the oil gel particles existing in the surface region of the hydrogel is less than the average particle size of the oil gel particles existing in the internal region of the hydrogel, and the average gap distance of the oil gel particles existing in the surface region of the hydrogel is greater than the average gap distance of the oil gel particles existing in the internal region of the hydrogel; and (4) the average particle size of the oil gel particles existing in the surface region of the hydrogel is less than the average particle size of the oil gel particles existing in the internal region of the hydrogel, and the average gap distance of the oil gel particles existing in the surface region of the hydrogel is less than the average gap distance of the oil gel particles existing in the internal region of the hydrogel.

[0011] The first non-uniform composition morphology is a more preferred composition morphology, in which the hydrophilic channels in the liquid guiding layer are branched from the surface to the inside, and the pore size decreases from the surface of the hydrogel to the inside of the hydrogel, so that the gradient capillary force of the hydrophilic channels is used for one-way liquid guiding, and the liquid absorption effect is the best. In actual wound dressing applications, different self-guiding and discharging dressings with different liquid guiding efficiencies can be used according to the wound conditions.

[0012] In another preferred embodiment, the oil gel particles are uniformly distributed in the liquid guiding layer in the thickness section.

[0013] Specifically, in the self-guiding and discharging dressing of the present application, the average gap distance of the oil gel particles in the liquid guiding layer is 0.5-50 μm.

[0014] Specifically, the average particle size of the oil gel particles is 5-100 μm, preferably 20-40 μm; and the particle size range of the oil gel particles is 0-200 μm.

[0015] Specifically, the hydrogel is obtained by light curing of a hydrogel pre-polymer solution, and the hydrogel pre-polymer solution comprises deionized water and polymer monomers, a first cross-linking agent and a first photoinitiator dissolved in the deionized water; the oil gel particles are obtained by light curing of an oil gel pre-polymer solution, and the oil gel pre-polymer solution comprises an oil liquid and a second cross-linking agent and a second photoinitiator dissolved in the oil liquid.

[0016] Specifically, the volume ratio of the oil gel particles to the hydrogel is 0.5:9.5 to 5:5, and the thickness of the liquid guiding layer accounts for 10%-60% of the overall thickness of the self-guiding and discharging dressing.

[0017] Preferably, the polymer monomers are selected from at least two of acrylamide, sodium alginate, acrylic acid and methacrylic acid, and sodium alginate is contained; the first cross-linking agent is N’N-methylene bisacrylamide or azobisisobutyronitrile; and the first photoinitiator is diethoxyphenylacetone, ammonium persulfate or 2-hydroxy-2-methylpropiophenone.

[0018] Preferably, the oil liquid is lauryl methacrylate, n-butyl methacrylate or stearyl methacrylate; the second cross-linking agent is ethylene glycol dimethacrylate; and the second photoinitiator is N’N-methylene bisacrylamide or 2-hydroxy-2-methylpropiophenone.

[0019] Preferably, the concentrations of the polymer monomers, the first cross-linking agent and the first photoinitiator in the hydrogel pre-polymer solution are 5-30 wt%, 0.04-3 wt% and 0.04-3 wt%, respectively, and are further preferably 10%-20 wt%, 0.1 wt% and 0.2 wt%, respectively.

[0020] Preferably, the concentrations of the second cross-linking agent and the second photoinitiator in the oil gel pre-polymer solution are 0.4-10wt%, 0.4-10wt% respectively, and further preferably 1wt%, 3wt% respectively.

[0021] Further preferably, the hydrogel is a sodium alginate / polyacrylamide type double network hydrogel, the polymer monomer is acrylamide and sodium alginate, and the oil liquid is methyl methacrylate laurate.

[0022] Based on the self-guiding dressing described above, the application further provides a preparation method of a self-guiding dressing, comprising: dispersing an oil gel pre-polymer solution into oil phase droplets in a hydrogel pre-polymer solution, and performing a curing treatment such as thermal curing or photo-curing on the hydrogel pre-polymer solution containing the oil phase droplets, thereby obtaining the self-guiding dressing.

[0023] For the self-guiding dressing with a non-uniform composition morphology liquid guiding layer, the following preparation method can be used, which specifically comprises the following steps:

[0024] Step 1: preparing a hydrogel pre-polymer solution and an oil gel pre-polymer solution;

[0025] Step 2: mixing and homogenizing the hydrogel pre-polymer solution and the oil gel pre-polymer solution, wherein the oil gel pre-polymer solution is dispersed into oil phase droplets as a dispersed phase, and the hydrogel pre-polymer solution is a continuous phase, thereby obtaining an oil-in-water emulsion;

[0026] Step 3: placing the oil-in-water emulsion, and the oil-in-water emulsion undergoes creaming, during which the oil phase droplets gather to the surface of the oil-in-water emulsion and are distributed in the upper layer of the hydrogel pre-polymer solution, so that the oil-in-water emulsion is stratified, and the stratified oil-in-water emulsion is subjected to a curing treatment, so that the oil phase droplets are cured into oil gel particles, and the hydrogel pre-polymer solution is cured into a hydrogel, thereby obtaining the self-guiding dressing.

[0027] Specifically, the step 1 specifically comprises: dissolving a polymer monomer, a first cross-linking agent and a first photoinitiator in deionized water, and mixing uniformly to obtain a hydrogel pre-polymer solution; and dissolving a second cross-linking agent and a second photoinitiator in an oil liquid to obtain an oil gel pre-polymer solution.

[0028] Preferably, the polymer monomer is selected from at least two of acrylamide, sodium alginate, acrylic acid and methacrylic acid, and contains sodium alginate; the first cross-linking agent is N’N-methylene bisacrylamide or azobisisobutyronitrile; and the first photoinitiator is diethoxyphenylacetone, ammonium persulfate or 2-hydroxy-2-methylpropiophenone.

[0029] Preferably, the oil liquid is lauryl methacrylate, n-butyl methacrylate or stearyl methacrylate; the second crosslinking agent is ethylene glycol dimethacrylate; the second photoinitiator is N’N-methylene bisacrylamide or 2-hydroxy-2-methylpropiophenone.

[0030] Preferably, the concentrations of the polymer monomer, the first crosslinking agent and the first photoinitiator in the hydrogel pre-polymer solution are 5-30wt%, 0.04-3wt% and 0.04-3wt% respectively, and are further preferably 10%-20wt%, 0.1wt% and 0.2wt% respectively.

[0031] Preferably, the concentrations of the second crosslinking agent and the second photoinitiator in the oil gel pre-polymer solution are 0.4-10wt% and 0.4-10wt% respectively, and are further preferably 1wt% and 3wt% respectively.

[0032] Preferably, in step 2, the mixture of the hydrogel pre-polymer solution and the oil gel pre-polymer solution is subjected to ultrasonic homogenization treatment using an ultrasonic cell disrupter.

[0033] Preferably, in step 2, the mixing ratio of the oil gel pre-polymer solution to the hydrogel pre-polymer solution is 0.5:9.5 to 5:5; when the mixing ratio of the oil gel pre-polymer solution to the hydrogel pre-polymer solution is too low, the emulsion oiling cannot occur and the layering occurs; and when the mixing ratio of the oil gel pre-polymer solution to the hydrogel pre-polymer solution is too high, the dispersed oil phase droplets cannot be formed in the liquid guiding layer after the emulsion oiling and layering, and thus the hydrophilic pores of the hydrogel cannot be formed between the oil gel particles.

[0034] Preferably, in step 3, the standing time of the oil-in-water emulsion is 0-48h, and the oil-in-water emulsion is subjected to curing treatment by ultraviolet light irradiation.

[0035] Preferably, in the preparation process, by controlling the component ratio, homogenization degree, standing time and other parameters, the composition and morphology of the liquid guiding layer can be controlled, and the liquid guiding layer with the first or second non-uniform composition and morphology can be obtained; and the liquid guiding layer with the third or fourth non-uniform composition and morphology can be obtained by inverting the liquid guiding layer with the first or second non-uniform composition and morphology and then compounding it with the hydrogel layer.

[0036] For the self-guided dressing of the liquid guiding layer with the uniform composition and morphology, the preparation method specifically includes the following steps:

[0037] Step 1', preparing a hydrogel pre-polymer solution and an oil gel pre-polymer solution;

[0038] Step 2', mixing and homogenizing the hydrogel pre-polymer liquid and the oil gel pre-polymer liquid, wherein the oil gel pre-polymer liquid is dispersed as oil phase droplets as a dispersed phase, and the hydrogel pre-polymer liquid is as a continuous phase, to obtain an oil-in-water emulsion;

[0039] Step 3', solidifying the homogenous oil-in-water emulsion to solidify the oil phase droplets into oil gel particles and solidify the hydrogel pre-polymer liquid into a hydrogel.

[0040] Preferably, the step 3' can further include pouring the homogenous oil-in-water emulsion onto the hydrogel pre-polymer liquid to form a dressing pre-polymer, and solidifying the dressing pre-polymer to solidify the oil phase droplets in the dressing pre-polymer into oil gel particles and solidify the hydrogel pre-polymer liquid in the dressing pre-polymer into a hydrogel, wherein the homogenous oil-in-water emulsion on the upper layer of the dressing pre-polymer is solidified into a liquid guiding layer, and the hydrogel pre-polymer liquid on the lower layer of the dressing pre-polymer is solidified into a liquid storage layer.

[0041] Preferably, the step 1' specifically includes dissolving the polymer monomer, the first cross-linking agent and the first photoinitiator in deionized water, and mixing uniformly to obtain the hydrogel pre-polymer liquid; and dissolving the second cross-linking agent and the second photoinitiator in an oil liquid to obtain the oil gel pre-polymer liquid.

[0042] Preferably, the polymer monomer is selected from at least two of acrylamide, sodium alginate, acrylic acid and methacrylic acid, and the at least two include sodium alginate; the first cross-linking agent is N'N-methylene bisacrylamide or azobisisobutyronitrile; and the first photoinitiator is diethoxyphenylacetone, ammonium persulfate or 2-hydroxy-2-methylpropiophenone.

[0043] Preferably, the oil liquid is lauryl methacrylate, n-butyl methacrylate or stearyl methacrylate; the second cross-linking agent is ethylene glycol dimethacrylate; and the second photoinitiator is N'N-methylene bisacrylamide or 2-hydroxy-2-methylpropiophenone.

[0044] Preferably, the concentrations of the polymer monomer, the first cross-linking agent and the first photoinitiator in the hydrogel pre-polymer liquid are 5-30wt%, 0.04-3wt% and 0.04-3wt% respectively, and are further preferably 10%-20wt%, 0.1wt% and 0.2wt% respectively.

[0045] Preferably, the concentrations of the second cross-linking agent and the second photoinitiator in the oil gel pre-polymer liquid are 0.4-10wt% and 0.4-10wt% respectively, and are further preferably 1wt% and 3wt% respectively.

[0046] Preferably, in the step 2', an ultrasonic cell disrupter is used to perform ultrasonic homogenization on the mixture of the hydrogel pre-polymer liquid and the oil gel pre-polymer liquid.

[0047] Preferably, in the step 2', the mixing ratio of the oil gel pre-polymer solution to the water gel pre-polymer solution is 0.5:9.5 to 5:5.

[0048] The present application has the following advantages:

[0049] The present application provides a self-draining dressing, comprising a liquid storage layer and a liquid guiding layer, wherein the liquid storage layer and the liquid guiding layer comprise a continuous water gel, and the liquid guiding layer further comprises oil gel particles distributed in the water gel, the water gel between adjacent oil gel particles forms a hydrophilic channel, wound exudate can be absorbed into the water gel along the hydrophilic channel between the oil gel particles by capillary force, and the oil gel particles arranged on the surface of the liquid guiding layer prevent the exchange of absorbed exudate back to the wound surface, effectively preventing adhesion between the dressing and the wound. The preparation method of the self-draining dressing of the present application is simple and fast, and the oil and water gel, i.e. the liquid storage layer and the liquid guiding layer, are prepared by one-step photopolymerization reaction. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a first structural form diagram of the self-draining dressing of the present application;

[0051] Figure 2 It is a second structural form diagram of the self-draining dressing of the present application;

[0052] Figure 3 It is a third structural form diagram of the self-draining dressing of the present application;

[0053] Figure 4 It is a fourth structural form diagram of the self-draining dressing of the present application;

[0054] Figure 5 It is a fifth structural form diagram of the self-draining dressing of the present application;

[0055] Figure 6 It is a flowchart of the first preparation method of the self-draining dressing of the present application;

[0056] Figure 7 It is a schematic diagram of the distribution of oil droplets in the oil-in-water emulsion in the emulsification process in step 3 of the first preparation method of the self-draining dressing of the present application;

[0057] Figure 8 It is a flowchart of the second preparation method of the self-draining dressing of the present application;

[0058] Figure 9 It is a confocal microscope photo showing the oil-in-water emulsion in the emulsification process in Example 1 of the present application;

[0059] Figure 10The microstructure photo of the liquid guiding layer of the self-guiding dressing of embodiment 1 of the present application under the confocal microscope;

[0060] Figure 11 The particle size distribution chart of the oil gel particles of embodiment 1 of the present application;

[0061] Figure 12 The scanning electron microscope photo of the surface and different thickness sections of the liquid guiding layer of the self-guiding dressing of embodiment 2 of the present application. DETAILED DESCRIPTION

[0062] The technical solutions of the present application will be further described in detail below in combination with specific embodiments. The following embodiments are only illustrative and explanatory of the present application and should not be interpreted as limiting the scope of protection of the present application. Any technology realized based on the above description of the present application is covered within the scope of protection intended by the present application.

[0063] Please refer to Figure 1 , Figure 1 The first structural form of the self-guiding dressing of the present application is shown in the schematic diagram. The self-guiding dressing of the first structural form of the present application comprises a liquid storage layer 1 and a liquid guiding layer 2 connected continuously with one side of the liquid storage layer 1. The liquid storage layer 1 and the liquid guiding layer 2 comprise a hydrogel 11 connected continuously. The liquid guiding layer 2 further comprises oil gel particles 21 distributed in the hydrogel 11. In the liquid guiding layer 2, the hydrogel 21 between adjacent oil gel particles 21 constitutes a hydrophilic channel 25. In the thickness section, the liquid guiding layer 2 presents a non-uniform composition form. The average particle size of the oil gel particles 21 existing in the surface region of the hydrogel 11 is greater than the average particle size of the oil gel particles 21 existing in the internal region of the hydrogel 11. The average gap distance of the oil gel particles 21 existing in the surface region of the hydrogel 11 is greater than the average gap distance of the oil gel particles 21 existing in the internal region of the hydrogel 11. The hydrophilic channels 25 in the liquid guiding layer 2 are in a branched state. The pore size thereof decreases from the surface of the hydrogel 11 to the inside of the hydrogel 11, so that the gradient capillary force of the hydrophilic channels 25 can be used for unidirectional liquid guiding, and the backflow of the absorbed liquid is inhibited. The wound exudate can be absorbed into the inside of the hydrogel 11 along the hydrophilic channels 25 between the oil gel particles 21 by capillary force, and the gradient arrangement of the oil gel particles 21 in the inside of the liquid guiding layer 2 prevents the backflow and exchange of the absorbed exudate to the wound surface.

[0064] Please refer to Figure 2 , Figure 2This is a schematic diagram of the second structural form of the self-extracting dressing of the present invention. Compared with the first structural form of the self-extracting dressing, the oleogel particles 21 are more sparsely distributed in the liquid-conducting layer 2. The average gap distance of the oleogel particles 21 existing in the surface area of ​​the hydrogel 11 is greater than that of the oleogel particles 21 existing in the internal area of ​​the hydrogel 11. The hydrophilic channels 25 between the oleogel particles 21 in the liquid-conducting layer 2 can also play a liquid-conducting role, but the liquid absorption efficiency is slightly worse than that of the first structural form of the self-extracting dressing.

[0065] like Figure 6 As shown, the above-mentioned self-extracting dressing with a non-uniform structural morphology can be obtained by the following preparation method, specifically including the following steps:

[0066] Step 1: Preparation of hydrogel prepolymer and oleogel prepolymer.

[0067] Step 2: Mix the hydrogel prepolymer and the olegel prepolymer and homogenize them, wherein the olegel prepolymer is dispersed into oil phase droplets as the dispersed phase and the hydrogel prepolymer is the continuous phase, to obtain an oil-in-water emulsion.

[0068] Step 3, as follows Figure 7 As shown, the oil-in-water emulsion is left to stand, and the oil-in-water emulsion undergoes emulsification. During this emulsification process, the oil phase droplets gather on the surface of the oil-in-water emulsion and are distributed on the upper layer of the hydrogel prepolymer, causing the oil-in-water emulsion to separate into layers. The separated oil-in-water emulsion is then irradiated with ultraviolet light to solidify the oil phase droplets into oil gel particles 21 and to solidify the hydrogel prepolymer into hydrogel 11, thus obtaining a self-extracting dressing.

[0069] [Hydrogel prepolymer solution]

[0070] The hydrogel prepolymer is obtained by uniformly mixing polymer monomers, a first crosslinking agent, and a first photoinitiator in deionized water. In order to improve the mechanical strength of the hydrogel, the present invention uses two polymer monomers containing sodium alginate to form a hydrogel with a dual network structure, which has stronger mechanical strength.

[0071] Preferably, the polymer monomer is selected from at least two of acrylamide, sodium alginate, acrylic acid, and methacrylic acid; the first crosslinking agent is N'N-methylenebisacrylamide or azobisisobutyronitrile; and the first photoinitiator is diethoxyacetophenone, ammonium persulfate, or 2-hydroxy-2-methylacetone.

[0072] Preferably, the concentrations of the polymer monomer, the first crosslinking agent, and the first photoinitiator in the hydrogel prepolymer solution are 5-30 wt%, 0.04-3 wt%, and 0.04-3 wt%, respectively, and more preferably 10%-20 wt%, 0.1 wt%, and 0.2 wt%, respectively.

[0073]

Olegel Prepolymer

[0074] The oleogel prepolymer is obtained by dissolving a second crosslinking agent and a second photoinitiator in oil.

[0075] Preferably, the oil is lauryl methacrylate, n-butyl methacrylate, or octadecyl methacrylate; the second crosslinking agent is ethylene glycol dimethacrylate; and the second photoinitiator is N'N-methylenebisacrylamide or 2-hydroxy-2-methylphenylacetone.

[0076] Preferably, the concentrations of the second crosslinking agent and the second photoinitiator in the oleogel prepolymer are 0.4-10 wt% and 0.4-10 wt%, respectively, and more preferably 1 wt% and 3 wt%, respectively.

[0077] This invention obtains an emulsified asymmetric oil-water gel by adjusting the spontaneous phase separation process of the oil and water phases. Both the oil-water gel, i.e., the liquid-conducting layer 2 and the liquid-reservoir layer 1, are prepared in one step via photopolymerization, making the operation simple and rapid. The specific principle is as follows:

[0078] The oil droplet deposition rate is calculated using Stokes' law, and the following Stokes sedimentation formula is used:

[0079]

[0080] Among them, V STOKES ρ represents the oil droplet migration rate. c Continuous phase density, ρ d Dispersed phase density, d oil droplet diameter, μ c The viscosity of the continuous phase and g are given by gravitational acceleration. It can be seen that during emulsification, larger oil droplets move faster, and after stratification, the oil droplets are roughly oriented from the liquid surface inwards according to their particle size, decreasing from largest to smallest. Furthermore, the above equation shows that increasing the viscosity of the continuous phase reduces the movement of the oil droplets, thus slowing down or even stopping the emulsification process.

[0081] Thus, when the emulsification reaches a certain stage, the oil-in-water emulsion is cross-linked to obtain an oil-hydrogel with a specific structure. Wound exudate can then be drawn into the hydrogel via capillary force through the hydrophilic channels between the oleogel particles 21. The gradient arrangement of the oleogel particles 21 within the gel prevents the absorbed exudate from flowing back to the wound surface for exchange.

[0082] Referring to Figure 3 , Figure 3 The third structural form of the self-draining dressing of the present application is shown in the schematic diagram. Compared with the self-draining dressing of the first structural form, the average particle size of the oil gel particles 21 present in the surface region of the hydrogel 11 is smaller than the average particle size of the oil gel particles 21 present in the internal region of the hydrogel 11, and the average interstitial distance of the oil gel particles 21 present in the surface region of the hydrogel 11 is greater than the average interstitial distance of the oil gel particles 21 present in the internal region of the hydrogel 11. The hydrophilic pores 25 between the oil gel particles 21 in the liquid guiding layer 2 gradually increase from the surface to the inside, and the liquid absorption efficiency is slightly poorer than that of the self-draining dressing of the first structural form. The self-draining dressing of the third composition form can be obtained by inverting the second non-uniform composition form of the liquid guiding layer and then compounding it with the hydrogel layer.

[0083] Referring to Figure 4 , Figure 4 The third structural form of the self-draining dressing of the present application is shown in the schematic diagram. Compared with the self-draining dressing of the first structural form, the average particle size of the oil gel particles 21 present in the surface region of the hydrogel 11 is smaller than the average particle size of the oil gel particles 21 present in the internal region of the hydrogel 11, and the average interstitial distance of the oil gel particles 21 present in the surface region of the hydrogel 11 is greater than the average interstitial distance of the oil gel particles 21 present in the internal region of the hydrogel 11. The hydrophilic pores 25 between the oil gel particles 21 in the liquid guiding layer 2 gradually increase from the surface to the inside, and the liquid absorption efficiency is slightly poorer than that of the self-draining dressing of the first structural form. The self-draining dressing of the third composition form can be obtained by inverting the second non-uniform composition form of the liquid guiding layer and then compounding it with the hydrogel layer.

[0084] Referring to Figure 5 , Figure 5 The fifth structural form of the self-draining dressing of the present application is shown in the schematic diagram. Compared with the self-draining dressing of the first structural form, the oil gel particles 21 are uniformly distributed in the liquid guiding layer 2 in the thickness section. Compared with the above-mentioned non-uniform structure liquid guiding layer, as shown in Figure 8 , the difference in preparation method mainly lies in that after homogenizing the hydrogel and the oil gel pre-polymer solution, the liquid guiding layer 2 is directly solidified without layering treatment, and the liquid storage layer 1 is obtained by directly solidifying the pure hydrogel pre-polymer solution.

[0085] The implementation process of the present application is illustrated by specific examples below, and the implementation effect is fully evaluated. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0086] Example 1:

[0087] Step 1. Preparation of pre-polymer solution

[0088] Preparation of 100 mL hydrogel pre-polymer solution: polymer monomer, first crosslinking agent and first photoinitiator were dissolved in deionized water, mixed uniformly to obtain a hydrogel pre-polymer solution, wherein 10 wt% acrylamide (polymer monomer), 2 wt% sodium alginate (polymer monomer, viscosity control), 0.006 wt% N’N-methylene bisacrylamide (first crosslinking agent), 0.006 wt% 2,2-diethoxyacetophenone (first photoinitiator).

[0089] Preparation of 100 mL oil gel pre-polymer solution: 86.3 g of lauryl methacrylate (oil liquid), 3 g of ethylene glycol dimethacrylate (second crosslinking agent) and 1 g of 2,2-diethoxyacetophenone (second photoinitiator) were taken and mixed uniformly to obtain an oil gel pre-polymer solution.

[0090] Step 2. Preparation of oil-in-water emulsion

[0091] An oil-in-water emulsion was obtained by taking 20 mL of the total volume of the hydrogel / oil gel pre-polymer solution with a water / oil volume ratio of 8:2, and using an ultrasonic cell crusher for ultrasonic homogenization. After ultrasonic treatment, 2 mL of the oil-in-water emulsion was taken and placed in a culture dish mold with a diameter of 35 mm.

[0092] Step 3. Emulsification process and solidification

[0093] The mold containing the oil-in-water emulsion was placed in a confocal microscope for observation. After standing for 15 h, the final product was obtained by solidification in an ultraviolet light reactor, thereby obtaining a self-guiding dressing.

[0094] Figure 9 The confocal microscope photos of the self-guiding dressing of Example 1 show the emulsification process of the oil-in-water emulsion during standing, as shown in FIG. 2, wherein the oil phase droplets gradually gather to the surface of the oil-in-water emulsion during the emulsification process, causing the oil-in-water emulsion to separate into two layers, and the oil phase droplets are distributed in the upper layer. Figure 9

[0095] The microstructure photos of the liquid guiding layer of the self-guiding dressing of Example 1 under the confocal microscope are shown in FIG. 3, wherein the oil phase droplets in the oil-in-water emulsion are distributed in the emulsification process, and the large particle oil phase droplets are mainly accumulated on the surface of the liquid, and the small particle oil phase droplets are accumulated below the large particle oil phase droplets. Figure 10 Figure 10 In this Example 1, the total thickness of the self-guiding dressing formed is 1.5 mm, the thickness of the liquid guiding layer is about 400 μm, and the proportion of the thickness of the liquid guiding layer to the total thickness of the self-guiding dressing is about 27%.

[0096] ​The formula for calculating the capillary force is fc= γp cos θ, where γ is the surface tension of the liquid, θ is the contact angle of the liquid with the channel, and p is the perimeter of the contact surface. In the gradient branching channel system, the contact angle and surface tension are fixed values, and the perimeter of the contact surface is actually the sum of the side lengths of the oil droplets on the same horizontal plane. The smaller the particle size of the oil droplets, the more tightly packed they are, the smaller the pore size of the hydrophilic channels, the larger the specific surface area and the contact surface perimeter, and the stronger the capillary force. The gradient arrangement of the oil gel particles 21 gradually increases the capillary force from the edge to the inside, and this asymmetric capillary force can achieve one-way water guidance on the surface of the wound.

[0097] Figure 11 For Figure 10 The oil gel particle size distribution diagram of the oil gel particles in the self-guiding dressing of Example 1 is shown in the figure. The particle size of the oil gel particles is calculated by the Nano measurer software. The particle size of the large particles on the upper surface is about 45 μm, the average particle size is 26.23 μm, the particle size of the small particles can be about 1 μm, and the overall average particle size is 13.22 μm.

[0098] According to the above Example 1 and the test results, it can be shown that the self-guiding dressing obtained according to the present application has the oil gel particles 21 oriented and stacked according to the particle size on the top of the hydrogel, and forms a branched gradient hydrophilic channel on the top of the hydrogel, so that the gradient capillary force of the hydrophilic channel can be used for one-way liquid guidance, and the backflow of the absorbed liquid can be inhibited. The wound exudate can be absorbed along the hydrophilic channels between the oil gel particles 21 and absorbed into the interior of the hydrogel by the capillary force, and the oil gel particles 21 arranged on the surface of the liquid guiding layer can prevent the backflow and exchange of the absorbed exudate to the surface of the wound, and avoid the adhesion between the dressing and the wound.

[0099] Example 2

[0100] Compared with Example 1, the difference is that in step 3, the oil-in-water emulsion after ultrasonic treatment is placed for 3 h and then cured in an ultraviolet light reactor to obtain the final product, thereby obtaining the self-guiding dressing.

[0101] Figure 12 The scanning electron microscope photos of the self-guiding dressing liquid guiding layer of Example 2 are shown in the figure, wherein Figure 12 a is the scanning electron microscope photo of the outermost surface of the liquid guiding layer 2 of the self-guiding dressing, Figure 12 b and 12c are the cross-sectional scanning electron microscope photos of different thicknesses, wherein Figure 12 c is the cross-sectional photo farthest from the surface of the liquid guiding layer 2, and Figure 12 It can be seen that in the self-guiding dressing of Example 2, the particle size of the oil gel particles 21 gradually decreases from the surface of the liquid guiding layer 2 to the inside, but the gap distance between the oil gel particles 21 gradually increases.

[0102] Example 3

[0103] Compared with example 1, the difference lies in that: after the oil-in-water emulsion is obtained by ultrasonic homogenization treatment in step 2, 2 mL of hydrogel pre-polymer liquid and oil-in-water emulsion are removed in turn and cured in the ultraviolet light reactor for 15 min to obtain the final product, and a uniform structure of the oil hydrogel is obtained.

[0104] Although the present application has been described in detail by the above examples, the above description is only to make those skilled in the art more easily understand the present application, and does not limit the implementation range of the present application, so that any equivalent changes and modifications made according to the shape, structure, characteristics and spirit described in the claims of the present application are still within the scope of the present application.

Claims

1. A self-draining dressing, characterized in that, It includes a liquid storage layer and a liquid guiding layer that is continuous with one side of the liquid storage layer; The liquid storage layer is a phase-continuous hydrogel; the liquid guiding layer comprises a phase-continuous hydrogel. The liquid-conducting layer also includes oleogel particles distributed in the hydrogel; The volume ratio of oleogel particles to hydrogel in the liquid-conducting layer is from 0.5:9.5 to 5:

5. In terms of thickness, the liquid-conducting layer exhibits a non-uniform composition, with the average particle size of the oleogel particles present on the surface of the hydrogel being larger than that of the oleogel particles present in the interior of the hydrogel. or In terms of thickness, the liquid-conducting layer exhibits a non-uniform composition, with the average particle size of the oleogel particles present on the surface of the hydrogel being smaller than that of the oleogel particles present in the interior region of the hydrogel; or In the thickness section, the oleogel particles with the same average particle size are uniformly distributed in the liquid-conducting layer.

2. The self-draining dressing according to claim 1, characterized in that, In the thickness section, the liquid guiding layer exhibits a non-uniform composition. When the average particle size of the oleogel particles existing in the surface region of the hydrogel is greater than the average particle size of the oleogel particles existing in the interior region of the hydrogel, in the thickness section, the average gap distance of the oleogel particles existing in the surface region of the hydrogel is greater than the average gap distance of the oleogel particles existing in the interior region of the hydrogel.

3. The self-draining dressing according to claim 1, characterized in that, In the thickness section, the liquid guiding layer exhibits a non-uniform composition. When the average particle size of the oleogel particles existing in the surface region of the hydrogel is greater than the average particle size of the oleogel particles existing in the interior region of the hydrogel, in the thickness section, the average gap distance of the oleogel particles existing in the surface region of the hydrogel is smaller than the average gap distance of the oleogel particles existing in the interior region of the hydrogel.

4. The self-draining dressing according to any one of claims 1 to 3, characterized in that, In terms of thickness cross-section, the liquid-conducting layer exhibits a non-uniform composition. When the average particle size of the oleogel particles present on the surface of the hydrogel is greater than that of the oleogel particles present in the interior of the hydrogel, the average particle size of the oleogel particles is 5-100 μm; the particle size range of the oleogel particles is 0-200 μm.

5. The self-draining dressing according to any one of claims 1 to 3, characterized in that, In terms of thickness, the liquid-conducting layer exhibits a non-uniform composition. When the average particle size of the oleogel particles present on the surface of the hydrogel is greater than that of the oleogel particles present in the interior of the hydrogel, the thickness of the liquid-conducting layer accounts for 10%-60% of the overall thickness of the self-extracting dressing.

6. The self-draining dressing according to claim 1, characterized in that, In the thickness section, the liquid guiding layer exhibits a non-uniform composition. When the average particle size of the oleogel particles existing in the surface region of the hydrogel is smaller than that of the oleogel particles existing in the interior region of the hydrogel, in the thickness section, the average gap distance of the oleogel particles existing in the surface region of the hydrogel is greater than that of the oleogel particles existing in the interior region of the hydrogel.

7. The self-draining dressing according to claim 1, characterized in that, In the thickness section, the liquid guiding layer exhibits a non-uniform composition. When the average particle size of the oleogel particles existing in the surface region of the hydrogel is smaller than the average particle size of the oleogel particles existing in the interior region of the hydrogel, in the thickness section, the average gap distance of the oleogel particles existing in the surface region of the hydrogel is smaller than the average gap distance of the oleogel particles existing in the interior region of the hydrogel.

8. The self-draining dressing according to any one of claims 1, 6-7, characterized in that, In terms of thickness cross-section, the liquid-conducting layer exhibits a non-uniform composition. When the average particle size of the oleogel particles existing in the surface region of the hydrogel is smaller than the average particle size of the oleogel particles existing in the interior region of the hydrogel, the average particle size of the oleogel particles is 5-100 μm; the particle size range of the oleogel particles is 0-200 μm.

9. The self-draining dressing according to any one of claims 1, 6-7, characterized in that, In terms of thickness cross-section, the liquid-conducting layer exhibits a non-uniform composition. When the average particle size of the oleogel particles present on the surface of the hydrogel is smaller than that of the oleogel particles present in the interior of the hydrogel, the thickness of the liquid-conducting layer accounts for 10%-60% of the overall thickness of the self-extracting dressing.

10. The self-draining dressing according to claim 1, characterized in that, When the oleogel particles are uniformly distributed in the liquid-conducting layer in the thickness section, the average particle size of the oleogel particles is 5-100 μm; the particle size range of the oleogel particles is 0-200 μm.

11. The self-draining dressing according to claim 1, characterized in that, In terms of thickness, when the oleogel particles are uniformly distributed in the liquid-conducting layer, the thickness of the liquid-conducting layer accounts for 10%-60% of the overall thickness of the self-conducting dressing.

12. A method for preparing a self-draining dressing according to claim 1, characterized in that, This includes dispersing an oleogel prepolymer into oil-phase droplets in a hydrogel prepolymer, and then curing the hydrogel prepolymer containing the oil-phase droplets to obtain a self-extracting dressing; specifically including: The hydrogel prepolymer and oleogel prepolymer are mixed and homogenized to obtain an oil-in-water emulsion. The oil-in-water emulsion is then allowed to stand to emulsify and separate into layers. The separated oil-in-water emulsion is then solidified to solidify the oil phase droplets into oleogel particles and the hydrogel prepolymer into a hydrogel, resulting in a self-extracting dressing with a non-uniform composition of the liquid-conducting layer in the thickness section.

13. The preparation method according to claim 12, characterized in that, Specifically, it includes: The hydrogel prepolymer and the oleogel prepolymer are mixed and homogenized to obtain an oil-in-water emulsion. The uniform oil-in-water emulsion is poured onto the hydrogel prepolymer to form a dressing prepolymer. The dressing prepolymer is then cured to solidify the oil phase droplets into oleogel particles and the hydrogel prepolymer into a hydrogel.

14. A method for preparing a self-draining dressing according to claim 1, characterized in that, This includes dispersing an oleogel prepolymer into oil-phase droplets in a hydrogel prepolymer, and then curing the hydrogel prepolymer containing the oil-phase droplets to obtain a self-extracting dressing. Specifically, the process includes: mixing and homogenizing a hydrogel prepolymer and an oleogel prepolymer to obtain an oil-in-water emulsion; pouring the uniform oil-in-water emulsion onto the hydrogel prepolymer to form a dressing prepolymer; and performing a curing treatment on the dressing prepolymer to solidify the oil phase droplets into oleogel particles and the hydrogel prepolymer into a hydrogel, thereby obtaining a self-extracting dressing in which the oleogel particles are uniformly distributed in the liquid-conducting layer on the thickness section.

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