Degradable medical dressing and preparation method thereof

Abstract

The invention discloses a degradable medical dressing and a preparation method thereof, and relates to the technical field of medical dressings, the preparation method comprises the following steps: adding sodium carboxymethyl cellulose and hydroxy propyl cellulose into deionized water, uniformly stirring, adding a 10wt% hydrochloric acid solution and epichlorohydrin, and adjusting the pH value of the solution to 0.2-0.5 to obtain a porous foam fabric; the preparation method comprises the following steps: adding a polyethylene glycol precursor containing beta-amino acrylate bonds into N, N-dimethylformamide, adding diphenylmethane diisocyanate and dibutyltin dilaurate, carrying out a heating reaction in a nitrogen atmosphere, adding imidazolidinyl urea, carrying out a heat preservation reaction, and adding chlorin e6 to obtain a hydrogel dressing; the preparation method comprises the following steps: cutting a porous foam fabric, partially immersing the fabric into a hydrogel dressing, drying, and treating with tannic acid-silicate to obtain the degradable medical dressing.

Description

Technical Field

[0001] The invention relates to the technical field of medical dressings, in particular to a degradable medical dressing and a preparation method thereof. Background Art

[0002] When treating burns caused by overheating or corrosive chemicals, the choice of wound dressing is critical to the healing process. Although traditional dressings can provide some protection in some cases, their effectiveness may be limited when it comes to burn wounds. An ideal wound dressing should have several key characteristics: first, it needs to be able to flexibly fit the irregular shape of the burn wound; second, it needs to be able to absorb wound exudate while maintaining a suitable moist environment to promote the healing process; third, the dressing material needs to have good biocompatibility and be able to effectively prevent wound infection; finally, the dressing change process should minimize secondary damage to the wound and avoid the pain and discomfort caused by high adhesion.

[0003] Hydrogel dressings are widely used in modern medicine due to their superior physical and biological properties, especially in burn treatment. Hydrogels not only have good wettability and can maintain the ideal humidity of the wound during the healing process, but also have excellent softness and adhesion, which can better adapt to the irregular shape of the wound and reduce damage to the wound when changing the dressing. In addition, the high moisture content and biocompatibility of hydrogel dressings enable them to effectively promote wound healing, reduce inflammatory reactions, and will not cause secondary infections.

[0004] With the increasing demand for burn treatment, how to solve the adhesion problem during the dressing replacement process needs to be solved urgently. Therefore, it is of great significance to invent a degradable medical dressing. Summary of the invention

[0005] The object of the present invention is to provide a degradable medical dressing and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A preparation method of a degradable medical dressing comprises the following steps: S1: adding sodium carboxymethyl cellulose and hydroxypropyl cellulose to deionized water, stirring evenly, adding 10wt% hydrochloric acid solution and epichlorohydrin, adjusting the pH of the solution to 0.2-0.5, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1-1.5h, freezing to -20--18°C to react for 20-22h, thawing, washing with deionized water, and drying in an environment of 40-45°C for 24h to obtain a porous foam fabric;

[0008] S2: Add a polyethylene glycol precursor containing a β-aminoacrylate bond to N,N-dimethylformamide, heat to 75-80°C, stir evenly, flush with nitrogen, add a solution of diphenylmethane diisocyanate and dibutyltin dilaurate in N,N-dimethylformamide, heat to 75-80°C under a nitrogen atmosphere for reaction for 5-6 hours, add imidazolidinyl urea, keep warm for reaction for 4-4.5 hours, add dry N,N-dimethylformamide, stir evenly, add dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0009] S3: The porous foam fabric is cut and partially immersed in the hydrogel dressing. After drying, it is treated with tannic acid-silicate to obtain a degradable medical dressing.

[0010] Furthermore, during the preparation of the porous foam fabric, the mass ratio of sodium carboxymethyl cellulose:hydroxypropyl cellulose is 0.6:(0.3-0.5).

[0011] Furthermore, in the preparation process of the hydrogel dressing, the molar ratio of polyethylene glycol precursor containing β-aminoacrylate bond: diphenylmethane diisocyanate: imidazolidinyl urea: dihydrochlorin e6 is (0.3-0.4):(2-3):(1.7-1.9):0.003.

[0012] Furthermore, the preparation method of the polyethylene glycol precursor containing β-amino acrylate bond comprises the following steps: step (1): adding polyethylene glycol, propiolic acid and p-toluenesulfonic acid hydrate into toluene, heating to reflux reaction for 24 hours under nitrogen atmosphere, concentrating under reduced pressure, adding the product into ether for precipitation, and obtaining functionalized polyethylene glycol;

[0013] Step (2): Add the functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30-32° C. and stir evenly, add diethanolamine, keep warm for 1-1.5 hours, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing a β-amino acrylate bond.

[0014] Furthermore, in the preparation process of the functionalized polyethylene glycol, the mass ratio of polyethylene glycol: propiolic acid: p-toluenesulfonic acid hydrate is 10:(3.57-3.76):(1.52-1.55).

[0015] Furthermore, in the preparation process of the polyethylene glycol precursor containing β-amino acrylate bonds, the molar ratio of functionalized polyethylene glycol to diethanolamine is 1:3.

[0016] Furthermore, the specific process of the tannic acid-silicate treatment includes: adding tannic acid to deionized water, stirring evenly, immersing the part of the porous foam fabric containing the hydrogel dressing after drying therein, adding a hyaluronic acid solution containing potassium silicate, stirring evenly, soaking for 3-4 days, and drying.

[0017] Furthermore, in the tannic acid-silicate treatment process, tannic acid is added to deionized water to form a solution with a concentration of 10-30wt%; in the hyaluronic acid solution containing potassium silicate, the solvent is a hyaluronic acid solution with a concentration of 4-5mg / mL, and the amount of solute potassium silicate added is 0.04-0.05g / mL.

[0018] Furthermore, the drying process includes any one of natural air drying, constant temperature drying or vacuum drying.

[0019] Furthermore, the porous foam fabric is immersed in the hydrogel dressing for 0.5-2 hours, and the drying treatment time is 2-10 hours.

[0020] Furthermore, the degradable medical dressing structure comprises: an upper portion of a porous foam fabric having a porous foam structure, and a lower portion of a hydrogel dressing containing tannic acid-silicate treatment.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention uses carboxymethyl cellulose to construct a porous foam fabric with a hierarchical pore structure through double cross-linking and porogen leaching, which not only disperses stress on multiple scales and gives the porous foam fabric super elasticity, but also deeply absorbs biological fluids (blood and body fluids) through its hierarchical porous surface and strong wetting force from abundant hydrophilic groups (such as hydroxyl and carboxyl groups), showing better absorbency than commercial elastic polyurethane foam, which is beneficial to improving the healing rate of patients' wounds, and can be completely degraded in the body and soil.

[0023] 2. In order to alleviate the pain caused by cell adhesion to the dressing during the dressing change of the burn wound, the porous foam fabric prepared above is used to absorb the wound of the continuous deep biological fluid. In addition, the present invention prepares a polyethylene glycol containing a β-aminoacrylate structure, and further prepares an imidazolidinyl urea reinforced polyurethane hydrogel dressing using it as a raw material. Finally, tannic acid and silicate are loaded in the hydrogel dressing network through a variety of non-covalent interactions. On the one hand, tannic acid and silicate can eliminate the overexpression of reactive oxygen, fight infection and produce a microenvironment that is beneficial to cells to accelerate in vitro wound healing. On the other hand, the hydrogel dressing continuously absorbs body fluids at the wound. When the body fluid absorption is in a saturated state, the upper porous foam fabric will absorb the body fluids. When in this situation, it means that the dressing needs to be changed. Visible light can be used to irradiate the medical dressing to make the medical dressing lose its mechanical strength and cell adhesion properties, so that the medical dressing can fall off naturally, greatly reducing the pain of the injured patient and greatly broadening the application scenarios of medical dressings. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0025] In the following examples, the specifications of sodium carboxymethyl cellulose are: degree of substitution = 0.72, molecular weight = 85000; the specifications of hydroxypropyl cellulose are: degree of substitution 0.52, molecular weight = 110000; the specifications of polyethylene glycol are: Mn = 4000 g / mol; the specifications of tannic acid are: Mw = 800 kDa; the specifications of hyaluronic acid are: Mw = 400 kDa; the commercially available PU foam fabric model is: 3M, 90619; and the remaining raw materials are all commercially available.

[0026] Embodiment 1: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying at 40 ° C for 24 h to obtain a porous foam fabric;

[0027] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol;

[0028] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0029] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 h, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 h, add dry N,N-dimethylformamide, stir evenly, add 0.003 mol of dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0030] S5: Cut the porous foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing in a 10wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 4 mg / mL, and the amount of potassium silicate added is 0.04 g / mL.

[0031] Example 2: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying at 40 ° C for 24 h to obtain a porous foam fabric;

[0032] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol;

[0033] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0034] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 h, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 h, add dry N,N-dimethylformamide, stir evenly, add 0.003 mol of dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0035] S5: Cut the porous foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing in a 30wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 5 mg / mL, and the amount of potassium silicate added is 0.05 g / mL.

[0036] Comparative Example 1: A method for preparing a degradable medical dressing, comprising the following steps: preparing functionalized polyethylene glycol using polyethylene glycol having a molecular weight of 1000;

[0037] The remaining steps are the same as those in Example 1.

[0038] Comparative Example 2: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying in a 40 ° C environment for 24 h to obtain a porous foam fabric;

[0039] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol;

[0040] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0041] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 hours, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 hours, add dry N,N-dimethylformamide, stir evenly, and obtain a hydrogel dressing;

[0042] S5: Cut the porous foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing in a 10wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 4 mg / mL, and the amount of potassium silicate added is 0.04 g / mL.

[0043] Comparative Example 3: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying at 40 ° C for 24 h to obtain a porous foam fabric;

[0044] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol; wherein the molecular weight of the polyethylene glycol was 1000;

[0045] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0046] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 hours, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 hours, add dry N,N-dimethylformamide, stir evenly, and obtain a hydrogel dressing;

[0047] S5: Cut the porous foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing in a 10wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 4 mg / mL, and the amount of potassium silicate added is 0.04 g / mL.

[0048] Comparative Example 4: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying at 40 ° C for 24 h to obtain a porous foam fabric;

[0049] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol;

[0050] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0051] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 h, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 h, add dry N,N-dimethylformamide, stir evenly, add 0.003 mol of dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0052] S5: The porous foam fabric is cut and partially immersed in the hydrogel dressing, and then dried to obtain a degradable medical dressing.

[0053] Comparative Example 5: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying at 40 ° C for 24 h to obtain a porous foam fabric;

[0054] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol;

[0055] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0056] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 h, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 h, add dry N,N-dimethylformamide, stir evenly, add 0.003 mol of dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0057] S5: Cut the porous foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing in a 5wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 4 mg / mL, and the amount of potassium silicate added is 0.04 g / mL.

[0058] Comparative Example 6: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 0.6 g of sodium carboxymethyl cellulose and 0.3 g of hydroxypropyl cellulose to 9.1 g of deionized water, stirring evenly, adding 3 mL of 10 wt% hydrochloric acid solution and 0.1 mL of epichlorohydrin, adjusting the pH of the solution to 0.35, centrifuging to remove bubbles, transferring the solution to a sealed mold, reacting at room temperature for 1 h, freezing to -18 ° C for 20 h, thawing, washing with deionized water, and freeze-drying in a 40 ° C environment for 24 h to obtain a porous foam fabric;

[0059] S2: 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate were added to 150 mL of toluene, heated to reflux for 24 h under a nitrogen atmosphere, concentrated under reduced pressure, and the product was added to ether for precipitation to obtain functionalized polyethylene glycol;

[0060] S3: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0061] S4: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 h, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 h, add dry N,N-dimethylformamide, stir evenly, add 0.003 mol of dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0062] S5: Cut the porous foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing after drying in a 10wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 3 mg / mL, and the amount of potassium silicate added is 0.03 g / mL.

[0063] Comparative Example 7: A method for preparing a degradable medical dressing, comprising the following steps: S1: adding 10 g of polyethylene glycol, 3.57 g of propiolic acid, and 1.52 g of p-toluenesulfonic acid hydrate to 150 mL of toluene, heating to reflux for 24 h under a nitrogen atmosphere, concentrating under reduced pressure, and adding the product to ether for precipitation to obtain functionalized polyethylene glycol;

[0064] S2: Add 1 mmol of functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30°C and stir evenly, add 3 mmol of diethanolamine, keep warm for 1 hour, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing β-amino acrylate bonds;

[0065] S3: Add 0.3 mol of polyethylene glycol precursor containing β-amino acrylate bond to N,N-dimethylformamide, heat to 75°C, stir evenly, flush with nitrogen to completely remove water, add 2.3 mol of diphenylmethane diisocyanate and 0.001 mol of dibutyltin dilaurate in N,N-dimethylformamide solution, heat to 75°C under nitrogen atmosphere for reaction for 5 h, add 1.52 mol of imidazolidinyl urea, keep warm for reaction for 4 h, add dry N,N-dimethylformamide, stir evenly, add 0.003 mol of dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing;

[0066] S4: Cut the commercially available PU foam fabric and partially immerse it in the hydrogel dressing. After drying, immerse the part of the porous foam fabric containing the hydrogel dressing in a 10wt% tannic acid deionized water solution, add a hyaluronic acid solution containing potassium silicate, stir evenly, soak for 4 days, and dry to obtain a degradable medical dressing. The concentration of the hyaluronic acid solution is 4 mg / mL, and the amount of potassium silicate added is 0.04 g / mL.

[0067] Experiment: Photodegradation performance test: The degradable medical dressings prepared in Examples 1-2 and Comparative Examples 1-3 were photodegradable using a visible light diode laser (16 mW / cm 2 ) The hydrogels were subjected to photodegradation. The hydrogels were irradiated for 90 min. To ensure that the films were in a fully expanded state, they were soaked in water for 24 h before irradiation.

[0068] The experimental data are shown in Table 1 below.

[0069] Table 1 Photodegradation performance test data of degradable medical dressings

[0070] Tensile strength / kPa Fracture strain / % Young's modulus / MPa Example 1 21 31.2 0.09 Example 2 23 29.8 0.09 Comparative Example 1 478 22.9 2.58 Comparative Example 2 1233 81.2 2.49 Comparative Example 3 3679 41.8 16.13

[0071] Conclusion: The degradable medical dressing prepared by the present invention has excellent photodegradation performance.

[0072] In Comparative Example 1, polyethylene glycol with a molecular weight of 1000 was used, and in Comparative Example 2, dihydrochlorin e6 was not added. In Comparative Example 3, polyethylene glycol with a molecular weight of 1000 was used and dihydrochlorin e6 was not added, all of which resulted in a decrease in the photodegradation performance of the degradable medical dressing.

[0073] Free radical scavenging performance test: The free radical scavenging activity of PTKH hydrogel was detected by DPPH assay. In short, DPPH was dissolved in methanol to prepare a stock solution (100 μM), and then the degradable medical dressings of Examples 1-2 and Comparative Examples 4-6 were immersed in DPPH (50 mg / ml). After 30 minutes, the reading was taken at 517 nm using an enzyme marker.

[0074] Antibacterial performance test: Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) were used as test bacteria. 1×10 5 The Luria-Bertani bacterial suspension with CFU / ml was co-cultured with the degradable medical dressings of Examples 1-2 and Comparative Examples 4-6 for 24 hours. The bacterial survival rate was evaluated by smear counting method.

[0075] The experimental data are shown in Table 2 below.

[0076] Table 2 Test data of photo-free radical performance / antibacterial performance of degradable medical dressings

[0077]

[0078] Conclusion: The biodegradable medical dressing prepared by the present invention has excellent DPPH free radical scavenging and antibacterial properties.

[0079] Since comparative example 4 was not treated with tannic acid-silicate, its DPPH radical scavenging performance was poor and it did not have antibacterial properties, the data was meaningless and the data was not displayed in the table. The tannic acid concentration in comparative example 5 was reduced, and the silicate concentration in comparative example 6 was reduced, both of which led to reduced DPPH radical scavenging and antibacterial properties of the degradable medical dressing.

[0080] Blood / body fluid absorption performance test: The blood and body fluid absorption rate was tested according to the protocol described in the British Pharmacopoeia 1995. Example 1 and Comparative Example 7 were weighed together (W 1 ) 5×5 cm porous foam fabric and commercial PU foam fabric were placed in a culture dish. Blood heated to 37°C (40 times the weight of the dressing) was added. The culture dish was placed in an incubator and maintained at 37°C for 30 minutes. One corner of the test dressing was suspended with forceps for 30 seconds and then reweighed (W 2 );

[0081] Absorption rate calculation = W 2-W 1 / 100cm 2

[0082] The experimental data are shown in Table 3 below.

[0083] Table 3 Porous foam fabric blood / body fluid absorption performance test table

[0084] <![CDATA[Blood absorption rate / g / 100 cm 2 > <![CDATA[Humoral absorption rate / g / 100 cm 2 > Example 1 40.1 37.9 Comparative Example 7 38.7 33.6

[0085] Conclusion: The porous foam fabric prepared by the present invention has excellent blood and body fluid absorption performance.

[0086] Comparative Example 7 uses common commercially available PU foam fabric, which lacks the hierarchical porous structure of the porous foam fabric prepared by the present invention, resulting in reduced blood and body fluid absorption performance.

[0087] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a degradable medical dressing, characterized in that: The following steps are involved: S1: Add sodium carboxymethyl cellulose and hydroxypropyl cellulose to deionized water, stir evenly, add 10wt% hydrochloric acid solution and epichlorohydrin, adjust the pH of the solution to 0.2-0.5, centrifuge to remove bubbles, transfer the solution to a sealed mold, react at room temperature for 1-1.5h, freeze to -20--18℃ and react for 20-22h, thaw, wash with deionized water, and dry in an environment of 40-45℃ for 24h to obtain a porous foam fabric; S2: Add a polyethylene glycol precursor containing a β-aminoacrylate bond to N,N-dimethylformamide, heat to 75-80°C, stir evenly, flush with nitrogen, add a solution of diphenylmethane diisocyanate and dibutyltin dilaurate in N,N-dimethylformamide, heat to 75-80°C under a nitrogen atmosphere for reaction for 5-6 hours, add imidazolidinyl urea, keep warm for reaction for 4-4.5 hours, add dry N,N-dimethylformamide, stir evenly, add dihydrochlorin e6, stir evenly, and obtain a hydrogel dressing; S3: After cutting the porous foam fabric, part of the fabric is immersed in the hydrogel dressing, and after drying, it is treated with tannic acid-silicate to obtain a degradable medical dressing.

2. The method for preparing a degradable medical dressing according to claim 1, characterized in that: During the preparation of the porous foam fabric, the mass ratio of sodium carboxymethyl cellulose to hydroxypropyl cellulose is 0.6:(0.3-0.5).

3. The method for preparing a degradable medical dressing according to claim 1, characterized in that: During the preparation of the hydrogel dressing, the molar ratio of polyethylene glycol precursor containing β-aminoacrylate bonds: diphenylmethane diisocyanate: imidazolidinyl urea: dihydrochlorin e6 is (0.3-0.4):(2-3):(1.7-1.9):0.

003.

4. The method for preparing a degradable medical dressing according to claim 1, characterized in that: The preparation method of a polyethylene glycol precursor containing a β-amino acrylate bond comprises the following steps: step (1): adding polyethylene glycol, propiolic acid, and p-toluenesulfonic acid hydrate into toluene, heating to reflux for 24 hours under a nitrogen atmosphere, concentrating under reduced pressure, and adding the product into ether for precipitation to obtain a functionalized polyethylene glycol; Step (2): Add the functionalized polyethylene glycol to anhydrous dichloromethane, heat to 30-32° C. and stir evenly, add diethanolamine, keep warm for 1-1.5 hours, concentrate under reduced pressure, add the product to ether for precipitation, and obtain a polyethylene glycol precursor containing a β-amino acrylate bond.

5. The method for preparing a degradable medical dressing according to claim 4, characterized in that: In the preparation process of functionalized polyethylene glycol, the mass ratio of polyethylene glycol: propiolic acid: p-toluenesulfonic acid hydrate is 10:(3.57-3.76):(1.52-1.55).

6. The method for preparing a degradable medical dressing according to claim 4, characterized in that: In the preparation of the polyethylene glycol precursor containing β-amino acrylate bonds, the molar ratio of functionalized polyethylene glycol:diethanolamine is 1:

3.

7. The method for preparing a degradable medical dressing according to claim 1, characterized in that: The specific process of the tannic acid-silicate treatment includes: adding tannic acid to deionized water, stirring evenly, immersing the part of the porous foam fabric containing the hydrogel dressing after drying into the deionized water, adding a hyaluronic acid solution containing potassium silicate, stirring evenly, soaking for 3-4 days, and drying.

8. The method for preparing a degradable medical dressing according to claim 7, characterized in that: During the tannic acid-silicate treatment process, tannic acid is added to deionized water to form a solution with a concentration of 10-30wt%; in the hyaluronic acid solution containing potassium silicate, the solvent is a hyaluronic acid solution with a concentration of 4-5mg / mL, and the amount of solute potassium silicate added is 0.04-0.05g / mL.

9. A degradable medical auxiliary material prepared according to the method for preparing a degradable medical dressing according to any one of claims 1 to 8.

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