Polytetrahydropyrimidinyl adhesive hydrogel dressing as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biomedical materials, and provides a polytetrahydropyrimidine-based adhesive hydrogel dressing as well as a preparation method and application thereof. According to the invention, tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide and N-isopropylacrylamide are used as raw materials, N, N '-methylene bisacrylamide is used as a cross-linking agent, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methyl propiophenone is used as an initiator, water is used as a solvent, and the hydrogel is prepared in a manner of initiating free radical polymerization by ultraviolet light. Then, Jelleine-I antibacterial peptide is grafted, and the polytetrahydropyrimidine-based adhesive hydrogel dressing is obtained. The hydrogel dressing prepared by the invention has the advantage of multiple functions, has good water absorption, adhesiveness, mechanical stability, biological safety, antibacterial property and anti-inflammatory property, has a wide application prospect, and provides a new thought for preparation and application of biomedical materials such as wound dressings and flexible wearable devices.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a polytetrahydropyrimidine-based adhesive hydrogel dressing and a preparation method and application thereof. Background Art

[0002] Hydrogel is a substance with a three-dimensional network structure and water as a dispersion medium. It can be divided into chemically cross-linked hydrogels and physically cross-linked hydrogels according to different cross-linking mechanisms. Since hydrogels can be used as carriers for drugs or cells in vivo and in vitro, they are considered to have potential applications in the field of biomedical materials. Although traditional wound dressings such as gauze, cotton wool, and bandages are widely used in clinical practice, they still have some insurmountable shortcomings. For example, gauze will adhere to the wound after absorbing blood, causing secondary bleeding and pain when changing the gauze; cotton wool has poor adhesion, and other dressings are needed to fix the injured area for a second time.

[0003] Hydrogel dressings have good biosafety, can provide a moist environment for wounds, promote oxygen exchange, and absorb exudates. But in addition to this, hydrogel dressings must have some other characteristics to be better used in clinical practice. For example, good water absorption can absorb exudate, achieve the effect of adhering to the wound, and is conducive to long-term moisturizing; appropriate adhesion enables hydrogel dressings to effectively cover irregular wounds, achieve the effect of rapid hemostasis, and avoid secondary trauma when changing dressings; sufficient mechanical strength can ensure the integrity of the dressing and avoid bacteria invading the wound due to material damage; when the wound is infected, bacteria may cause persistent inflammation at the site of infection. If the inflammatory response is too severe, it will delay healing and lead to the formation of chronic wounds. Therefore, hydrogel dressings also need to have certain antibacterial and anti-inflammatory functions.

[0004] However, current hydrogel dressings are difficult to achieve good water absorption, adhesion, mechanical stability, biosafety, as well as antibacterial and anti-inflammatory properties, which limits their clinical application. Summary of the invention

[0005] In view of this, the present invention provides a polytetrahydropyrimidine-based adhesive hydrogel dressing and a preparation method and application thereof. The polytetrahydropyrimidine-based adhesive hydrogel dressing provided by the present invention has good water absorption, adhesion, mechanical stability, biosafety, antibacterial and anti-inflammatory properties, has multifunctional advantages, and has broad application prospects.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A method for preparing a polytetrahydropyrimidine-based adhesive hydrogel dressing comprises the following steps:

[0008] Tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, a crosslinking agent, an initiator and water are mixed to obtain a hydrogel precursor solution; the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone;

[0009] Expose the hydrogel precursor solution to ultraviolet light to obtain a hydrogel;

[0010] Activating the hydrogel with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to obtain an activated hydrogel;

[0011] The activated hydrogel and the Jelleine-I antimicrobial peptide solution are mixed to carry out a grafting reaction to obtain the polytetrahydropyrimidine-based adhesive hydrogel dressing.

[0012] Preferably, the method for preparing tetrahydropyrimidine methacrylate comprises:

[0013] Hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride are mixed and reacted to obtain the methacrylic acid tetrahydropyrimidine; the mass ratio of the hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride is 2-6:32-34:0.8-2:6-8.

[0014] Preferably, the reaction comprises: first dissolving hydroxytetrahydropyrimidine in trifluoroacetic acid, then adding trifluoromethanesulfonic acid for a first reaction, and then adding methacryloyl chloride for a second reaction; the temperature of the first reaction is 0°C and the time is 5 to 30 minutes; the temperature of the second reaction is 0°C and the time is 0.5 to 4 hours.

[0015] Preferably, the preparation method of dopamine methacrylamide comprises:

[0016] Performing a first mixing of a mixed solution of dopamine hydrochloride, methanol and triethylamine to obtain a first mixed solution;

[0017] Mixing methacryloyl chloride and tetrahydrofuran for a second time to obtain a second mixed solution;

[0018] Mixing triethylamine and methanol to obtain a third mixed solution;

[0019] Alternately dropping the second mixed solution and the third mixed solution into the first mixed solution to react, thereby obtaining the dopamine methacrylamide;

[0020] The volume ratio of dopamine hydrochloride, methanol and triethylamine in the first mixed solution is 0.5-1:8-12:0.5-1; the volume ratio of methacryloyl chloride and tetrahydrofuran in the second mixed solution is 0.5-1:3-7; the volume ratio of triethylamine and methanol in the third mixed solution is 0.5-2:0.5-2; the volume ratio of methanol in the first mixed solution, tetrahydrofuran in the second mixed solution and methanol in the third mixed solution is 8-12:3-7:0.5-2.

[0021] Preferably, in the hydrogel precursor solution, the mass of tetrahydropyrimidine methacrylate is 8% to 32% of the mass of water, the mass of dopamine methacrylamide is 0.04% to 0.2% of the mass of water, the mass of acrylamide is 3% to 10% of the mass of water, the mass of N-isopropylacrylamide is 8% to 32% of the mass of water, the mass of the cross-linking agent is 0.01% to 0.08% of the mass of water, and the mass of the initiator is 0.2% to 0.6% of the mass of water.

[0022] Preferably, the ultraviolet irradiation time is 60 to 100 minutes.

[0023] Preferably, the activation comprises: immersing the hydrogel in a mixed solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, wherein the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide in the mixed solution is 2 to 40 mg / mL, and the concentration of N-hydroxysuccinimide is 2 to 40 mg / mL; and the immersion time is 0.5 to 2 h.

[0024] Preferably, the concentration of the Jelleine-I antimicrobial peptide solution is ≥ 2 mmol / L; the temperature of the grafting reaction is 4 to 25° C., and the time is 2 to 12 hours.

[0025] The present invention also provides a polytetrahydropyrimidine-based adhesive hydrogel dressing prepared by the preparation method described in the above scheme, comprising a hydrogel and a Jelleine-I antimicrobial peptide grafted on the hydrogel; the hydrogel is prepared from tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropylacrylamide, a crosslinking agent, an initiator and water.

[0026] The present invention also provides the use of the polytetrahydropyrimidine-based adhesive hydrogel dressing described in the above scheme in the preparation of biomedical materials.

[0027] The invention provides a preparation method of a polytetrahydropyrimidine-based adhesive hydrogel dressing, comprising the following steps: mixing tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropylacrylamide, a crosslinking agent, an initiator and water to obtain a hydrogel precursor solution; the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone; subjecting the hydrogel precursor solution to ultraviolet light to obtain a hydrogel; activating the hydrogel with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to obtain an activated hydrogel; and mixing the activated hydrogel with Jelleine-I antimicrobial peptide for grafting reaction to obtain the polytetrahydropyrimidine-based adhesive hydrogel dressing. The present invention adopts tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, and N-isopropyl acrylamide as main raw materials to prepare hydrogel, wherein acrylamide and N-isopropyl acrylamide are used to form the basic structure of hydrogel, tetrahydropyrimidine methacrylate can introduce tetrahydropyrimidine structure in hydrogel, tetrahydropyrimidine has strong binding ability with water molecules, high solubility in water environment, and can maintain strong hydration even in high salt environment, which is conducive to absorbing the interface hydration layer to promote the adhesion of hydrogel to the surface, and has anti-inflammatory properties; dopamine methacrylamide can introduce dopamine structure in hydrogel, which can play a role of viscosity increase, and improve the antioxidant and anti-inflammatory properties of hydrogel. At the same time, the present invention grafts Jelleine-I antimicrobial peptide on hydrogel, and Jelleine-I antimicrobial peptide is a typical amphiphilic antimicrobial peptide with low toxicity and strong antimicrobial activity, and is not easy to produce bacterial resistance. In summary, the hydrogel dressing prepared by the present invention has multifunctional advantages, good water absorption, adhesion, mechanical stability, biosafety, antibacterial and anti-inflammatory properties, and broad application prospects. It provides new ideas for the preparation and application of biomedical materials such as wound dressings and flexible wearable devices.

[0028] In addition, the present invention prepares the hydrogel by ultraviolet light-induced free radical polymerization, which is simple to operate, low in cost, and easy to achieve mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The water absorption performance test results of the hydrogels prepared in Example 1 and Comparative Examples 1 to 3;

[0030] Figure 2 The adhesion performance test results of the polytetrahydropyrimidine-based adhesive hydrogel dressing prepared in Example 2;

[0031] Figure 3 The mechanical stability performance test results of the polytetrahydropyrimidine-based adhesive hydrogel dressing prepared in Example 3;

[0032] Figure 4 The test results of the bacterial proliferation experiment of the polytetrahydropyrimidine-based adhesive hydrogel dressing prepared in Example 4, wherein the left side is the bacterial proliferation curve of Staphylococcus aureus, and the right side is the bacterial proliferation curve of Escherichia coli;

[0033] Figure 5 The biosafety test results of the polytetrahydropyrimidine-based adhesive hydrogel dressing prepared in Example 5;

[0034] Figure 6 These are the anti-inflammatory performance test results of the polytetrahydropyrimidine-based adhesive hydrogel dressing prepared in Example 6. DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing a polytetrahydropyrimidine-based adhesive hydrogel dressing, comprising the following steps:

[0036] Tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, a crosslinking agent, an initiator and water are mixed to obtain a hydrogel precursor solution; the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone;

[0037] Expose the hydrogel precursor solution to ultraviolet light to obtain a hydrogel;

[0038] Activating the hydrogel with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to obtain an activated hydrogel;

[0039] The activated hydrogel and Jelleine-I antimicrobial peptide are mixed for grafting reaction to obtain the polytetrahydropyrimidine-based adhesive hydrogel dressing.

[0040] The invention mixes tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, a crosslinking agent, an initiator and water to obtain a hydrogel precursor solution; the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

[0041] In the present invention, the preparation method of tetrahydropyrimidine methacrylate preferably comprises: mixing hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride to react to obtain the tetrahydropyrimidine methacrylate; the mass ratio of hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride is preferably 2-6:32-34:0.8-2:6-8, specifically 5.4:33:1:7; the reaction preferably comprises: first dissolving hydroxytetrahydropyrimidine in trifluoroacetic acid, then adding trifluoromethanesulfonic acid for a first reaction, and then adding methacryloyl chloride for a second reaction; the temperature of the first reaction is 0°C and the time is 5-30min; the temperature of the second reaction is 0°C and the time is 0.5-4h, specifically 2h. In a specific embodiment of the present invention, the method of dissolving hydroxytetrahydropyrimidine is preferably: adding hydroxytetrahydropyrimidine to trifluoroacetic acid, sealing with plastic wrap, and vigorously stirring under ice bath conditions until completely dissolved. After the second reaction is completed, the present invention preferably performs post-treatment on the obtained product liquid to obtain the tetrahydropyrimidine methacrylate, and the post-treatment preferably comprises: adding diethyl ether dropwise to the product liquid under ice bath conditions, filtering after precipitation of a white solid to obtain a crude product, purifying the crude product with methanol / diethyl ether, washing the obtained purified product with diethyl ether and filtering to obtain tetrahydropyrimidine methacrylate, the structural formula of which is shown in Formula I; the purification specifically comprises: dissolving the crude product in methanol, and then precipitating with diethyl ether; the volume ratio of methanol to diethyl ether is preferably 1:100.

[0042]

[0043] In the present invention, the preparation method of dopamine methacrylamide preferably comprises: first mixing dopamine hydrochloride, methanol and triethylamine to obtain a first mixed liquid; second mixing methacryloyl chloride and tetrahydrofuran to obtain a second mixed liquid; mixing triethylamine and methanol to obtain a third mixed liquid; and alternately dropping the second mixed liquid and the third mixed liquid into the first mixed liquid to react to obtain the dopamine methacrylamide. In the present invention, the volume ratio of dopamine hydrochloride, methanol and triethylamine in the first mixed solution is preferably 0.5-1:8-12:0.5-1, specifically 0.7:10:0.7; the volume ratio of methacryloyl chloride and tetrahydrofuran in the second mixed solution is preferably 0.5-1:3-7, specifically 0.6:5; the volume ratio of triethylamine and methanol in the third mixed solution is preferably 0.5-2:0.5-2, specifically 1:1; the volume ratio of methanol in the first mixed solution, tetrahydrofuran in the second mixed solution and methanol in the third mixed solution is preferably 8-12:3-7:0.5-2, specifically 10:5:1; the first mixing, the second mixing and the third mixing are preferably carried out under ice bath conditions; in a specific embodiment of the present invention, the method of alternately adding the second mixed solution and the third mixed solution to the first mixed solution is specifically: the first mixed solution is placed in a three-necked flask, and the second mixed solution and the third mixed solution are placed in two In the constant pressure dropping funnel, two constant pressure dropping funnels are installed on a three-necked flask, and the dropping speed of the two constant pressure dropping funnels is adjusted to achieve alternating dropping; after the second mixed solution and the third mixed solution are added dropwise, the present invention preferably stirs the obtained feed liquid at room temperature for 1h, and then post-treats the obtained product feed liquid to obtain the dopamine methacrylamide; the post-treatment preferably includes: extracting the obtained product feed liquid with ethyl acetate to obtain an organic phase; washing the organic phase with saturated brine and dilute hydrochloric acid in sequence, and then drying, filtering and rotary evaporating in sequence to obtain a residual liquid; mixing the residual liquid with n-hexane to obtain a solid crude product, purifying the solid crude product with ethyl acetate / n-hexane, and then filtering to obtain the dopamine methacrylamide; the concentration of the dilute hydrochloric acid is preferably 1 mol / L; the purification is specifically: dissolving the solid crude product in ethyl acetate, and then precipitating with n-hexane, and the volume ratio of ethyl acetate to n-hexane is preferably 1:100.

[0044] In the present invention, in the hydrogel precursor solution, the mass of tetrahydropyrimidine methacrylate is preferably 8% to 32% of the mass of water, specifically 8%, 16% or 32%, more preferably 16%, the mass of dopamine methacrylamide is preferably 0.04% to 0.2% of the mass of water, specifically 0.0465%, 0.093% or 0.186%, more preferably 0.186%, the mass of acrylamide is preferably 3% to 10% of the mass of water, specifically 3%, 5% or 10%, more preferably 5%, the mass of N-isopropylacrylamide is preferably 8% to 3 ... The mass of the cross-linking agent is 0.01-0.08% of the mass of water, specifically 0.0133%, 0.0266%, 0.0399%, 0.0532%, 0.0665% or 0.0798%, more preferably 0.0532%, the mass of the initiator is 0.2%-0.6% of the mass of water, specifically 0.2%, 0.4% or 0.6%, more preferably 0.2%; the water is water after impurities are removed, specifically deionized water, ultrapure water or distilled water. In the specific embodiment of the present invention, deionized water is preferably used.

[0045] After obtaining the hydrogel precursor solution, the present invention subjects the hydrogel precursor solution to ultraviolet light to obtain a hydrogel. In the present invention, the ultraviolet light exposure time is preferably 60 to 100 minutes, more preferably 80 minutes; the present invention preferably removes bubbles from the hydrogel precursor solution and pours it into a mold, covers the mold with a quartz glass plate, and then subjects it to ultraviolet light exposure; the degassing is preferably vacuum degassing, specifically carried out in a vacuum dryer; the mold is preferably a polytetrafluoroethylene mold; the ultraviolet light exposure is preferably carried out using an ultraviolet crosslinking instrument. After the ultraviolet light exposure is completed, the obtained hydrogel is preferably soaked in deionized water for 30 minutes to remove the monomers that have not reacted completely.

[0046] After obtaining the hydrogel, the present invention activates the hydrogel with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to obtain an activated hydrogel. In the present invention, the activation preferably includes: soaking the hydrogel in a mixed solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide; the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide in the mixed solution is preferably 2 to 40 mg / mL, specifically 12 mg / mL, the concentration of N-hydroxysuccinimide is preferably 2 to 40 mg / mL, specifically 12 mg / mL, the solvent of the activator solution is water, specifically deionized water, ultrapure water or distilled water, in a specific embodiment of the present invention, deionized water is preferably used; the soaking time is 0.5 to 2 hours, preferably 0.5 hours, and the soaking temperature is preferably room temperature; the soaking is preferably carried out under oscillation conditions, and the oscillation speed is preferably 200r / min. After the soaking is completed, the activated hydrogel is preferably cleaned with a phosphate buffer solution and then sterilized with ultraviolet light; the ultraviolet light sterilization time is preferably 30 minutes.

[0047] After obtaining the activated hydrogel, the present invention mixes the activated hydrogel and the Jelleine-I antimicrobial peptide solution for grafting reaction to obtain the polytetrahydropyrimidine-based adhesive hydrogel dressing. In the present invention, the concentration of the Jelleine-I antimicrobial peptide solution is preferably ≥2mmol / L, more preferably ≥4mmol / L, further preferably 4.096-8.192mmol / L, specifically 4.096mmol / L, 6.144mmol / L or 8.192mmol / L, and most preferably 4.096mmol / L; in a specific embodiment of the present invention, when the concentration of the Jelleine-I antimicrobial peptide solution is 4.096mmol / L or more, the obtained hydrogel dressing has the effect of simultaneously inhibiting Staphylococcus aureus and Escherichia coli; the temperature of the grafting reaction is preferably 4-25°C, and the time is preferably 2-12h; after the grafting reaction is completed, the present invention preferably washes the obtained hydrogel dressing with sterile water, and then air-dries it in the dark at room temperature; the time of the air-drying in the dark is preferably 4h.

[0048] The present invention also provides a polytetrahydropyrimidine-based adhesive hydrogel dressing prepared by the preparation method described in the above scheme, comprising a hydrogel and a Jelleine-I antimicrobial peptide grafted on the hydrogel; the hydrogel is prepared from tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropylacrylamide, a cross-linking agent, an initiator and water; the polytetrahydropyrimidine-based adhesive hydrogel dressing provided by the present invention has good water absorption, adhesion, mechanical stability, biosafety, antibacterial and anti-inflammatory properties, and has broad application prospects.

[0049] The present invention also provides the use of the polytetrahydropyrimidine-based adhesive hydrogel dressing described in the above scheme in the preparation of biomedical materials; the biomedical materials preferably include wound dressings or flexible wearable devices.

[0050] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] Add hydroxytetrahydropyrimidine to trifluoroacetic acid, seal with plastic wrap, stir vigorously with magnetic stirring in an ice bath at 0°C until completely dissolved, add trifluoromethanesulfonic acid and stir for 5 minutes, then add methacryloyl chloride and stir for 2 hours, continuously add 30 mL of ether dropwise in an ice bath at 0°C to precipitate a white solid powder, filter with filter paper, further purify with methanol / ether, wash with ether several times, and filter to obtain methacrylic acid tetrahydropyrimidine; wherein, the mass ratio of hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride is 5.4:33:1:7, and the amount of hydroxytetrahydropyrimidine used is 1 g.

[0053] Under an ice bath at 0°C, dopamine hydrochloride is dissolved in a methanol-triethylamine mixed solvent to obtain a first mixed solution, methacryloyl chloride and tetrahydrofuran are mixed for a second time to obtain a second mixed solution; triethylamine and methanol are mixed for a third time to obtain a third mixed solution; the second mixed solution and the third mixed solution are alternately added dropwise to the first mixed solution, then the ice bath is removed, stirred at room temperature for 1 hour, an equal volume of ethyl acetate is added to extract to obtain an organic phase, which is washed with saturated brine and 1 mol / L dilute hydrochloric acid in turn, dried and filtered over anhydrous sodium sulfate for multiple times, rotary evaporated, and n-hexane is added to the residual liquid to obtain a brown solid, which is further purified by ethyl acetate / n-hexane and filtered to obtain dopamine methacrylamide; the volume ratio of dopamine hydrochloride, methanol and triethylamine in the first mixed solution, methacryloyl chloride and tetrahydrofuran in the second mixed solution, and triethylamine and methanol in the third mixed solution is 0.7:10:0.7:0.6:5:1:1; wherein the amount of dopamine hydrochloride is 1 g.

[0054] Tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, crosslinking agent N,N'-methylenebisacrylamide, initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and deionized water are mixed to obtain a hydrogel precursor solution, and the hydrogel precursor solution is poured into a polytetrafluoroethylene mold after removing bubbles in a vacuum dryer, covered with a quartz glass plate, and irradiated with an ultraviolet crosslinker for 80 minutes to obtain a hydrogel; wherein the mass percentages of tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, N,N'-methylenebisacrylamide and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone in the solvent deionized water are 16%, 0.186%, 5%, 16%, 0.0532%, and 0.2%, respectively, and the amount of deionized water is 5g. The obtained hydrogel is recorded as AAm / NIPAAm / ectoine / DMA.

[0055] Comparative Example 1

[0056] The other conditions are the same as those in Example 1, except that tetrahydropyrimidine methacrylate and dopamine methacrylamide are omitted. Specifically, acrylamide, N-isopropylacrylamide, crosslinking agent N,N'-methylenebisacrylamide, initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and deionized water are mixed to obtain a hydrogel precursor solution, wherein the mass percentages of acrylamide, N-isopropylacrylamide, crosslinking agent N,N'-methylenebisacrylamide and initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone in deionized water are 5%, 16%, 0.0532% and 0.2%, respectively. The obtained hydrogel is recorded as AAm / NIPAAm.

[0057] Comparative Example 2

[0058] The other conditions are the same as those in Example 1, except that the addition of dopamine methacrylamide is omitted. Specifically, tetrahydropyrimidine methacrylate, acrylamide, N-isopropylacrylamide, crosslinking agent N,N'-methylenebisacrylamide, initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and deionized water are mixed to obtain a hydrogel precursor solution, wherein the mass percentages of tetrahydropyrimidine methacrylate, acrylamide, N-isopropylacrylamide, crosslinking agent N,N'-methylenebisacrylamide and initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone in deionized water are 16%, 5%, 16%, 0.0532% and 0.2%, respectively. The obtained hydrogel is recorded as AAm / NIPAAm / ectoine.

[0059] Comparative Example 3

[0060] The other conditions are the same as those in Example 1, except that the addition of tetrahydropyrimidine methacrylate is omitted. Specifically, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, crosslinking agent N,N'-methylenebisacrylamide, initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and deionized water are mixed to obtain a hydrogel precursor solution, wherein the mass percentages of dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, crosslinking agent N,N'-methylenebisacrylamide and initiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone in deionized water are 0.186%, 5%, 16%, 0.0532% and 0.2%, respectively. The obtained hydrogel is recorded as AAm / NIPAAm / DMA.

[0061] Take the hydrogels prepared in Example 1 and Comparative Examples 1 to 3, with at least 3 samples in each group, soak each group of hydrogels in phosphate buffer for 48 hours to reach swelling equilibrium, weigh them, and record the mass as W1. After the hydrogels are freeze-dried, weigh them again, and record the mass as W2. The water absorption rate (g / g) of the hydrogels is calculated according to the following formula: Water absorption rate = (W1-W2) / W2. The test results are as follows: Figure 1 shown.

[0062] Figure 1 The test results show that the addition of tetrahydropyrimidine methacrylate can increase the water absorption rate of the hydrogel, which is beneficial for the hydrogel dressing to absorb exudate and achieve the effect of adhesion to the wound, and is beneficial for long-term moisturizing, laying a good foundation for its use as a wound dressing in the biomedical field.

[0063] Example 2

[0064] The preparation method of the hydrogel is the same as that of Example 1; the hydrogel obtained after ultraviolet irradiation is immersed in deionized water for 30 minutes to remove the unreacted monomers, and then immersed in a mixed solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, wherein the concentrations of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in the mixed solution are both 12 mg / mL, and the shaker is oscillated at a speed of 200 r / min for 30 minutes, and then washed 3 times with phosphate buffer, disinfected with ultraviolet light for 30 minutes, immersed in a 4.096 mmol / L Jelleine-I antimicrobial peptide solution at 4°C for 2 hours, washed 3 times with sterile water for 10 minutes each time, and air-dried at room temperature in the dark for 4 hours to obtain a polytetrahydropyrimidine-based adhesive hydrogel dressing.

[0065] The adhesion performance of the hydrogel dressing was tested by a probe tensile test using an electronic universal testing machine. The hydrogel dressing, glass, pig skin and chicken bone were cut into 1 cm × 1 cm squares. The hydrogel dressing was fixed to the upper probe with super glue, and the glass, pig skin or chicken bone was fixed to the lower test base. 10 μL of deionized water was dripped on the glass, pig skin or chicken bone. After the hydrogel dressing was in contact with the glass, pig skin or chicken bone with a force of 1 N for 30 seconds, it was pulled upward at a speed of 30 mm / min until it was completely separated from the glass, pig skin or chicken bone. The maximum force required for separation was divided by the contact area of ​​the hydrogel dressing with the base material (1 cm). 2 , and the adhesion strength of the hydrogel dressing was obtained. The test results are as follows Figure 2 shown.

[0066] Figure 2 The test results in the present invention show that the polytetrahydropyrimidine-based adhesive hydrogel dressing prepared by the present invention has certain adhesion, can meet the use requirements of wound dressings in clinical practice, can be quickly applied to the wound to achieve a hemostatic effect, and has moderate adhesion strength, is easy to replace, and is not prone to causing secondary damage.

[0067] Example 3

[0068] Refer to Example 2, except that the prepared hydrogel dressing is a cylinder with a diameter of 35 mm and a thickness of 2 mm. The storage modulus (G') and loss modulus (G") of the hydrogel dressing are tested over time using a rheometer, with the test frequency set to 1 Hz, the shear stress set to 1 Pa, and the test time being 5 min.

[0069] The test results are as follows Figure 3 As shown, Figure 3 The test results in show that the storage modulus of the hydrogel dressing prepared by the present invention is greater than the loss modulus, and the modulus curve remains stable as time goes by, indicating that the hydrogel dressing has certain elasticity, good stability and the ability to resist external forces.

[0070] Example 4

[0071] Refer to Example 2, except that the prepared hydrogel was immersed in a mixed solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide and shaken for 30 minutes, washed with phosphate buffer three times, and sterilized with ultraviolet light for 30 minutes, and then immersed in Jelleine-I antimicrobial peptide solutions of different concentrations and incubated for 2 hours. The concentration of Jelleine-I antimicrobial peptide was set to: 0 mmol / L, 0.512 mmol / L, 1.024 mmol / L, 2.048 mmol / L, 4.096 mmol / L, 6.144 mmol / L, and 8.192 mmol / L.

[0072] The optimal concentration of antimicrobial peptides was screened for Staphylococcus aureus and Escherichia coli through inhibition zone experiments, bacterial proliferation experiments, and clone formation experiments. Inhibition zone experiment: The absorbance of the bacterial suspension was diluted to 0.1, and 100 μL was added to the LB agar plate and evenly spread. Then, the hydrogel dressing obtained after incubation with different concentrations of antimicrobial peptides was spread on the agar plate, cultured in a 37°C, 5% CO2 incubator for 15 hours, and the size of the inhibition zone was observed. Bacterial proliferation experiment: A cylindrical hydrogel with a diameter of 10 mm and a thickness of 2 mm was co-incubated with 400 μL of bacterial solution with an absorbance of 0.1, and the absorbance of the bacterial solution at 600 nm was measured at different time points to draw a bacterial proliferation curve. Clone formation experiment: The experimental group co-incubated the hydrogel with a bacterial solution with an absorbance of 0.1, and the control group co-incubated the bacterial solution without hydrogel. After 24 hours of incubation, the bacterial solution was diluted 300 times, 20 μL was added to the LB agar plate, spread evenly, incubated for 15 hours, and the number of colonies was observed.

[0073] The results of the inhibition zone experiment and the colony formation experiment showed that the polytetrahydropyrimidine-based hydrogel without antimicrobial peptides itself did not have antibacterial properties. For Staphylococcus aureus, the hydrogel co-incubated with antimicrobial peptides at a concentration of 4.096mmol / L and above had excellent antibacterial effects, and for Escherichia coli, the hydrogel co-incubated with antimicrobial peptides at a concentration of 2.048mmol / L and above had excellent antibacterial effects; the test results of the bacterial proliferation experiment are shown in Figure 4 As shown, Figure 4 The left side shows the bacterial growth curve of Staphylococcus aureus, and the right side shows the bacterial growth curve of Escherichia coli. Figure 4 The test results show that the hydrogel co-incubated with antimicrobial peptides at a concentration of 4.096 mmol / L and above has the effect of simultaneously inhibiting Staphylococcus aureus and Escherichia coli. Therefore, the antimicrobial peptides were selected to be co-incubated with the hydrogel at the lowest effective concentration of 4.096 mmol / L.

[0074] Example 5

[0075] Refer to Example 2, except that the hydrogel extract is prepared by mixing 1 mL of complete culture medium for every 0.1 g of hydrogel dressing. 4000 mouse fibroblasts are plated in a 96-well plate, incubated for 12 hours, the old culture medium is discarded, 100 μL of complete culture medium is added to the control group, and 100 μL of hydrogel extract is added to the experimental group. Culture in a 37°C, 5% CO2 incubator for 24 hours, 48 ​​hours, and 72 hours. At each time point, the old culture medium is discarded, 100 μL of complete culture medium containing 10% CCK-8 reagent is added, and incubated for 1 hour. The absorbance at 450 nm is measured to calculate the cell survival rate.

[0076] The test results are as follows Figure 5As shown, the CCK-8 experimental results show that after the extract of the hydrogel dressing prepared by the present invention was cultured with cells for 24h, 48h, and 72h, the cell viability was close to 100%, demonstrating the excellent biosafety of the hydrogel dressing, and providing a basis and potential possibility for its application in the biomedical field.

[0077] Example 6

[0078] Refer to Example 2, except that the prepared hydrogel dressing is a cylinder with a diameter of 35 mm and a thickness of 2 mm. The experimental group placed the hydrogel dressing in a 6-well plate, while the control group did not contain the hydrogel dressing. Mouse mononuclear macrophages were cultured at a rate of 1×10 6 The number of cells was plated on a 6-well plate and incubated for 12 hours. The old culture medium was discarded, and 2.5 mL of 0.1 μg / mL lipopolysaccharide solution prepared with complete culture medium was added to the experimental group and the positive control group, and 2.5 mL of complete culture medium was added to the negative control group. The cells were cultured in a 37°C, 5% CO2 incubator for 48 hours, and the supernatant was collected to detect the concentrations of inflammatory factors IL-6, IL-1β and TNF-α.

[0079] The test results are as follows Figure 6 As shown, Figure 6 The test results show that the hydrogel dressing prepared by the present invention can reduce the expression of inflammatory factors IL-6, IL-1β and TNF-α, and has a certain anti-inflammatory ability, which provides theoretical support and potential possibility for its use as a wound dressing in clinical practice to promote wound healing.

[0080] In summary, the hydrogel dressing prepared by the present invention has multifunctional advantages, and possesses good water absorption, adhesion, mechanical stability, biosafety, antibacterial and anti-inflammatory properties. It provides a new idea for the preparation and application of biomedical materials such as wound dressings and flexible wearable devices, and has broad application prospects.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a polytetrahydropyrimidine-based adhesive hydrogel dressing, characterized in that: The following steps are involved: Tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropyl acrylamide, a crosslinking agent, an initiator and water are mixed to obtain a hydrogel precursor solution; the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone; Expose the hydrogel precursor solution to ultraviolet light to obtain a hydrogel; Activating the hydrogel with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide to obtain an activated hydrogel; The activated hydrogel and the Jelleine-I antimicrobial peptide solution are mixed to carry out a grafting reaction to obtain the polytetrahydropyrimidine-based adhesive hydrogel dressing.

2. The preparation method according to claim 1, characterized in that: The preparation method of tetrahydropyrimidine methacrylate comprises: Hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride are mixed and reacted to obtain the methacrylic acid tetrahydropyrimidine; the mass ratio of the hydroxytetrahydropyrimidine, trifluoroacetic acid, trifluoromethanesulfonic acid and methacryloyl chloride is 2-6:32-34:0.8-2:6-8.

3. The preparation method according to claim 2, characterized in that: The reaction comprises: first dissolving hydroxytetrahydropyrimidine in trifluoroacetic acid, then adding trifluoromethanesulfonic acid for a first reaction, and then adding methacryloyl chloride for a second reaction; the temperature of the first reaction is 0° C. and the time is 5 to 30 minutes; the temperature of the second reaction is 0° C. and the time is 0.5 to 4 hours.

4. The preparation method according to claim 1, characterized in that: The preparation method of dopamine methacrylamide comprises: performing a first mixing of dopamine hydrochloride, methanol and triethylamine to obtain a first mixed solution; Mixing methacryloyl chloride and tetrahydrofuran for a second time to obtain a second mixed solution; Mixing triethylamine and methanol to obtain a third mixed solution; Alternately dropping the second mixed solution and the third mixed solution into the first mixed solution to react, thereby obtaining the dopamine methacrylamide; The volume ratio of dopamine hydrochloride, methanol and triethylamine in the first mixed solution is 0.5-1:8-12:0.5-1; the volume ratio of methacryloyl chloride and tetrahydrofuran in the second mixed solution is 0.5-1:3-7; the volume ratio of triethylamine and methanol in the third mixed solution is 0.5-2:0.5-2; the volume ratio of methanol in the first mixed solution, tetrahydrofuran in the second mixed solution and methanol in the third mixed solution is 8-12:3-7:0.5-2.

5. The preparation method according to claim 1, characterized in that: In the hydrogel precursor solution, the mass of tetrahydropyrimidine methacrylate is 8% to 32% of the mass of water, the mass of dopamine methacrylamide is 0.04% to 0.2% of the mass of water, the mass of acrylamide is 3% to 10% of the mass of water, the mass of N-isopropylacrylamide is 8% to 32% of the mass of water, the mass of the crosslinking agent is 0.01% to 0.08% of the mass of water, and the mass of the initiator is 0.2% to 0.6% of the mass of water.

6. The preparation method according to claim 1, characterized in that: The ultraviolet irradiation time is 60 to 100 minutes.

7. The preparation method according to claim 1, characterized in that: The activation comprises: soaking the hydrogel in a mixed solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide; the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide in the mixed solution is 2 to 40 mg / mL, and the concentration of N-hydroxysuccinimide is 2 to 40 mg / mL; and the soaking time is 0.5 to 2 hours.

8. The preparation method according to claim 1, characterized in that: The concentration of the Jelleine-I antimicrobial peptide solution is ≥2mmol / L; the temperature of the grafting reaction is 4-25°C, and the time is 2-12h.

9. A polytetrahydropyrimidine-based adhesive hydrogel dressing prepared by the preparation method according to any one of claims 1 to 8, comprising a hydrogel and a Jelleine-I antimicrobial peptide grafted on the hydrogel; the hydrogel is prepared from tetrahydropyrimidine methacrylate, dopamine methacrylamide, acrylamide, N-isopropylacrylamide, a cross-linking agent, an initiator and water.

10. Use of the polytetrahydropyrimidine-based adhesive hydrogel dressing according to claim 9 in the preparation of biomedical materials.

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