A wound recovery dressing for post-surgical care of tumors and a method of making the same

Abstract

This invention provides a wound healing dressing for postoperative care of tumor patients and its preparation method, belonging to the field of postoperative dressing technology. The dressing comprises boric acid-grafted GelMA, caffeoyl tartaric acid-grafted CSMA, aldehyde-modified diallyl tartaramide, sodium alginate, catechins, ferric chloride, and calcium chloride. Its preparation process utilizes dynamic imine bonds, UV-induced covalent cross-linking, ionic cross-linking, and metal coordination to construct a multi-layered cross-linked interpenetrating network structure. The resulting dressing possesses both high strength and good toughness, allowing it to closely adhere to irregular wound surfaces. The rapid initial release of catechins provides immediate antioxidant and hemostatic effects, while catechols are continuously and slowly released under the influence of the microenvironment. Simultaneously, cationic chitosan, catechins, and iron ions synergistically provide antibacterial effects, and calcium alginate promotes coagulation, while GelMA promotes cell adhesion and proliferation, comprehensively promoting wound healing, reducing the risk of infection, and making it suitable for the care of complex wounds after tumor surgery.

Description

Technical Field

[0001] This invention belongs to the field of postoperative dressing technology, and particularly relates to a wound recovery dressing for postoperative care of tumor patients and its preparation method. Background Technology

[0002] Tumor surgery is one of the most effective treatments for solid tumors; however, the quality of postoperative wound healing directly affects the patient's recovery process and prognosis. Postoperative wounds often face numerous challenges, including but not limited to: bleeding and hematoma formation, management of tissue exudate, risk of pathogenic microorganism infection, and the potential risk of local tumor cell residue and recurrence. Therefore, developing a novel wound dressing that can effectively promote wound healing while also possessing anti-infection, hemostatic, and even tumor recurrence-inhibiting functions is of significant clinical importance.

[0003] Traditional wound dressings, such as gauze and cotton pads, while offering some absorption of exudate and physical protection, have inherent limitations, including a tendency to adhere to the wound and cause secondary damage, an inability to maintain a moist healing environment, and a lack of bioactivity. To overcome these shortcomings, hydrogel dressings based on natural or synthetic polymers have emerged. Due to their hydrophilic three-dimensional network structure, hydrogels can absorb large amounts of tissue fluid, providing and maintaining a moist microenvironment conducive to cell proliferation and migration. They also possess good biocompatibility and adjustable physical properties, making them a research hotspot in postoperative wound care.

[0004] However, most existing hydrogel dressings still face the following bottlenecks that urgently need to be addressed: First, their mechanical properties and tissue compatibility are insufficient, especially when dealing with complex and irregular wounds that may exist after tumor resection, where it is difficult to simultaneously ensure both the dressing's fit and mechanical stability. Second, their functionality is limited, typically only providing moisturizing or passive antibacterial effects, making it difficult to achieve active and controllable release of drugs or active factors to synergistically promote healing. Third, tumor resection surgeries (such as radical mastectomy for breast cancer and resection of soft tissue sarcomas) often result in irregularly shaped and depressed wounds, making it difficult for traditional flat dressings to fit perfectly, easily creating dead spaces, leading to exudate accumulation, and increasing the risk of infection. Therefore, there is an urgent need for a new type of wound recovery dressing for postoperative care of tumors. Summary of the Invention

[0005] In view of the above situation and to overcome the defects of the prior art, the present invention provides a multifunctional wound recovery dressing with reinforced structure, multiple cross-linking, and antibacterial, hemostatic and healing-promoting functions, and a method for preparing the same.

[0006] To achieve the above objectives, the following technical solution is adopted: On the one hand, the present invention provides a wound recovery dressing for postoperative care of tumor patients, comprising the following components in parts by weight: 30-40 parts of boric acid-grafted GelMA, 15-25 parts of caffeoyl tartaric acid-grafted CSMA, 8-12 parts of aldehyde-modified diallyl tartaramide, 5-10 parts of sodium alginate, 2-5 parts of catechin, 0.5-1 part of ferric chloride, 1-3 parts of calcium chloride, 80-100 parts of purified water, and 2-4 parts of glycerin; wherein the boric acid-grafted GelMA is obtained by reacting p-bromophenylboronic acid with methacrylamide gelatin, the caffeoyl tartaric acid-grafted CSMA is obtained by reacting caffeoyl tartaric acid with methacrylamide chitosan, and the aldehyde-modified diallyl tartaramide is obtained by reacting p-formylbenzoic acid with N,N'-diallyl-L-tartaramide.

[0007] Further, the caffeoyl tartaric acid-grafted CSMA is prepared by the following steps: caffeoyl tartaric acid and methacrylated chitosan are added to N,N-dimethylformamide, then EDC and NHS are added, and the reaction is carried out at 25-30℃ and a stirring rate of 200-300 r / min for 4-6 h. After the reaction is completed, the mixture is purified by dialysis for 24-36 h, and then freeze-dried to obtain caffeoyl tartaric acid-grafted CSMA.

[0008] Furthermore, the mass ratio of caffeoyl tartaric acid to methacryloxychitosan is 1:2.5-3.5, and the molar ratio of EDC, NHS to caffeoyl tartaric acid is 1.2:1.2:1.

[0009] Further, the aldehyde-modified diallyl tartaramide is prepared by the following steps: p-formylbenzoic acid and N,N'-diallyl-L-tartaramide are mixed, dissolved in anhydrous ethanol, and then p-toluenesulfonic acid is added. The mixture is reacted at 60-70°C under reflux for 3-4 hours. After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture is purified by recrystallization and dried to obtain aldehyde-modified diallyl tartaramide.

[0010] Further, the molar ratio of p-formylbenzoic acid to N,N'-diallyl-L-tartaramide is 1:1.1-1.3, and the amount of p-toluenesulfonic acid is 0.8-1.2% of the total mass of the reactants p-formylbenzoic acid and N,N'-diallyl-L-tartaramide.

[0011] Further, the boric acid-grafted GelMA is prepared by the following steps: methacrylamide gelatin is dissolved in phosphate buffer at pH 7.4 to prepare a solution, p-bromophenylboronic acid and triethylamine are added, and the mixture is stirred and reacted at 35-40℃ under nitrogen protection for 5-7 hours. After the reaction is completed, the mixture is centrifuged to remove impurities, dialyzed for 48 hours, and freeze-dried to obtain boric acid-grafted GelMA.

[0012] Furthermore, the mass concentration of the methacrylamide gelatin in the phosphate buffer is 5-8%, the molar ratio of methacrylamide gelatin to p-bromophenylboronic acid is 1:0.8-1.0, and the amount of triethylamine used is 1.5-2 times the molar amount of p-bromophenylboronic acid.

[0013] On the other hand, the present invention also provides a method for preparing the wound healing dressing for postoperative care of tumor patients, comprising the following steps:

[0014] (1) Place 90% of the total mass of purified water in a constant temperature water bath at 30-35℃, add boric acid grafted GelMA and caffeoyl tartaric acid grafted CSMA, stir until completely dissolved, add glycerol, and continue stirring for 15-20 min to obtain a mixed mother liquor.

[0015] (2) Add aldehyde-modified diallyl tartaramide to the mixed mother liquor, adjust the pH of the system to 8.0-8.5, and stir at 35-40℃ for 30-40 min to form preliminary cross-linking;

[0016] (3) Continue to add sodium alginate and catechin, stir evenly, add 2-hydroxy-2-methyl-1-phenyl-1-propanone, purge with nitrogen to remove oxygen for 10-15 min, and irradiate with ultraviolet light with a wavelength of 365 nm for 15-20 min to carry out photo-initiated crosslinking.

[0017] (4) Dissolve ferric chloride and calcium chloride in the remaining deionized water and slowly add them to the above system. Stir for 20-30 minutes. Finally, pour the cross-linking system into a mold and dry it in a vacuum drying oven at 40-45℃ for 12-16 hours. After demolding, cut it into the required size and sterilize it to obtain the wound recovery dressing for postoperative care of tumors.

[0018] Furthermore, the amount of 2-hydroxy-2-methyl-1-phenyl-1-propanone used is 0.3-0.5% of the total mass of the system.

[0019] In the above preparation process, the aldehyde groups in aldehyde-modified diallyl tartaramide react with the amino groups on GelMA and CSMA to form dynamic imine bonds, endowing the dressing with self-healing ability and network framework strength. Under ultraviolet light irradiation, the methacryloyl groups (from GelMA and CSMA) and diallyl groups (from aldehyde-modified diallyl tartaramide) in the system undergo free radical polymerization to form a covalent cross-linked network, giving the dressing excellent mechanical strength. Calcium ions undergo ionic cross-linking with sodium alginate, further strengthening the network. At the same time, the coordination ability of iron ions can coordinate with the carboxyl groups on sodium alginate and CSMA, and can also form reversible coordination / boronic acid ester bonds with the catechol groups (from caffeoyl tartaric acid grafted CSMA and catechin) and borate groups in the system. The introduction of this multiple physical cross-linking points not only further strengthens the network, but also endows the material with an energy dissipation mechanism, making it both strong and tough, less prone to brittleness, and able to better fit and adapt to the dynamic deformation of human tissue.

[0020] The dressing prepared in this invention contains catechins and weakly coordinated ions that can be rapidly released in the early stages of wound healing, exerting immediate antioxidant, free radical scavenging, and hemostatic effects. Components fixed by covalent bonds (Schiff bases, photopolymerization networks) (such as GelMA and CSMA backbones) form a stable framework that is not easily released. Caffeoyl tartaric acid grafted onto the catechol structure in CSMA and catechins undergo reversible coordination / esterification reactions with iron ions or boric acid. Under pH changes in the wound microenvironment or in the presence of certain metabolites, these coordination bonds can slowly dissociate, thereby achieving a continuous and slow release of caffeoyl tartaric acid and catechins. This avoids the burst release of active ingredients, prolongs their effective duration, and achieves long-lasting wound care.

[0021] In addition, this invention endows the dressing with multiple biological activities, promoting wound healing in multiple ways: cationic CSMA itself has certain antibacterial activity; catechin, as a natural broad-spectrum antibacterial agent, can destroy bacterial cell membranes; third, iron ions themselves have antibacterial properties and can also form a complex with catechol structure with Fenton-like reaction activity, generating hydroxyl radicals in the wound microenvironment to achieve chemokinetic antibacterial activity.

[0022] The dressing prepared by this invention also has highly efficient hemostatic and procoagulant functions: sodium alginate cross-links with calcium ions to form a gel, which can rapidly absorb water from the blood, concentrate clotting factors, and play a role in physical hemostasis. At the same time, polyphenolic substances such as catechins and caffeoyl tartaric acid also have astringent effects, which can promote platelet aggregation and activation, further accelerating the hemostasis process.

[0023] The dressing prepared in this invention promotes cell adhesion, proliferation, and tissue regeneration: GelMA retains the RGD sequence of gelatin, providing excellent adhesion sites for fibroblasts, vascular endothelial cells, etc., promoting cell migration and proliferation on the dressing. CSMA, as a chitosan derivative, has good biocompatibility and healing-promoting properties. Caffeoyl tartaric acid and other polyphenols possess antioxidant and anti-inflammatory activities, downregulating inflammatory factor levels and creating a favorable microenvironment for wound healing. The combined effect of multiple mechanisms accelerates angiogenesis and granulation tissue growth.

[0024] The beneficial effects of this invention are as follows: This invention constructs an interpenetrating and synergistically reinforced network structure through dynamic imine bonds, photo-initiated covalent crosslinking, ionic crosslinking of calcium ions and sodium alginate, and multiple coordination interactions of iron ions with carboxyl groups, catechol, and boric acid groups. This design enables the dressing to possess both high strength and good toughness, effectively dissipating energy, preventing brittleness, and conforming to the dynamic deformation of human tissue, making it particularly suitable for complex wounds with irregular shapes and depressions after tumor resection. The catechins in the dressing prepared by this invention can be rapidly released in the early stages of wound healing, exerting immediate antioxidant, astringent, and hemostatic effects. Meanwhile, catechols bound by reversible coordination bonds are continuously and slowly released under the influence of the wound microenvironment. This invention also exhibits a synergistic antibacterial mechanism, significantly enhancing anti-infection capabilities, especially showing good inhibitory effects against drug-resistant bacteria, helping to reduce the risk of wound infection after tumor surgery. The dressing prepared by this invention also possesses highly efficient hemostatic and procoagulant functions, promoting cell adhesion, proliferation, and tissue regeneration, and optimizing the healing microenvironment. Attached Figure Description

[0025] Figure 1 This is a comparison chart showing the test results of the wound healing effect in rats according to the present invention.

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples are all purchased from commercial channels.

[0030] Example 1

[0031] A wound healing dressing for postoperative care of tumor patients and its preparation method

[0032] The wound healing dressing for post-tumor surgery care comprises the following components in parts by weight: 30 parts boric acid-grafted GelMA, 15 parts caffeoyl tartaric acid-grafted CSMA, 8 parts aldehyde-modified diallyl tartaramide, 5 parts sodium alginate, 2 parts catechin, 0.5 parts ferric chloride, 1 part calcium chloride, 80 parts purified water, and 2 parts glycerin.

[0033] The caffeoyl tartaric acid-grafted CSMA was prepared by the following steps: caffeoyl tartaric acid and methacrylated chitosan were added to N,N-dimethylformamide, then EDC and NHS were added, and the mixture was reacted at 25°C and a stirring rate of 200 r / min for 4 h. After the reaction was completed, the mixture was purified by dialysis for 24 h, and then freeze-dried to obtain caffeoyl tartaric acid-grafted CSMA. The mass ratio of caffeoyl tartaric acid to methacrylated chitosan was 1:2.5, and the molar ratio of EDC, NHS and caffeoyl tartaric acid was 1.2:1.2:1.

[0034] The aldehyde-modified diallyl tartaramide is prepared by the following steps: p-formylbenzoic acid and N,N'-diallyl-L-tartaramide are mixed, dissolved in anhydrous ethanol, and then p-toluenesulfonic acid is added. The mixture is reacted at 60°C under reflux for 3 hours. After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture is purified by recrystallization and dried to obtain aldehyde-modified diallyl tartaramide. The molar ratio of p-formylbenzoic acid to N,N'-diallyl-L-tartaramide is 1:1.1, and the amount of p-toluenesulfonic acid is 0.8% of the total mass of the reactants p-formylbenzoic acid and N,N'-diallyl-L-tartaramide.

[0035] The boric acid-grafted GelMA was prepared by the following steps: methacrylamide gelatin was dissolved in a phosphate buffer solution at pH 7.4 to prepare a solution; p-bromophenylboronic acid and triethylamine were added; the mixture was stirred and reacted at 35°C under nitrogen protection for 5 hours; after the reaction was completed, the mixture was centrifuged to remove impurities, dialyzed for 48 hours, and freeze-dried to obtain boric acid-grafted GelMA; wherein the mass concentration of the methacrylamide gelatin in the phosphate buffer solution was 5%, the molar ratio of methacrylamide gelatin to p-bromophenylboronic acid was 1:0.8, and the amount of triethylamine used was 1.5 times the molar amount of p-bromophenylboronic acid.

[0036] A method for preparing a wound healing dressing for postoperative care of tumor patients includes the following steps:

[0037] (1) Place 90% of the total mass of purified water in a 30°C constant temperature water bath, add boric acid-grafted GelMA and caffeoyl tartaric acid-grafted CSMA, stir until completely dissolved, add glycerol, and continue stirring for 15 min to obtain a mixed mother liquor.

[0038] (2) Add aldehyde-modified diallyl tartaramide to the mixed mother liquor, adjust the pH of the system to 8.0, and stir at 35°C for 30 min to form preliminary cross-linking;

[0039] (3) Continue to add sodium alginate and catechin, stir evenly, add 2-hydroxy-2-methyl-1-phenyl-1-propanone, the amount of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 0.3% of the total mass of the system, purge with nitrogen gas to remove oxygen for 10 min, and irradiate with ultraviolet light with a wavelength of 365 nm for 15 min to carry out photo-initiated crosslinking;

[0040] (4) Dissolve ferric chloride and calcium chloride in the remaining deionized water, slowly add them to the above system, stir for 20 minutes, and finally pour the cross-linking system into the mold, place it in a vacuum drying oven at 40°C and dry for 12 hours. After demolding, cut it into the required size, and after sterilization, the wound recovery dressing for postoperative care of tumors is obtained.

[0041] Example 2

[0042] A wound healing dressing for postoperative care of tumor patients and its preparation method

[0043] The wound healing dressing for post-tumor surgery care comprises the following components in parts by weight: 40 parts boric acid-grafted GelMA, 25 parts caffeoyl tartaric acid-grafted CSMA, 12 parts aldehyde-modified diallyl tartaramide, 10 parts sodium alginate, 5 parts catechin, 1 part ferric chloride, 3 parts calcium chloride, 100 parts purified water, and 4 parts glycerin.

[0044] The caffeoyl tartaric acid-grafted CSMA was prepared by the following steps: caffeoyl tartaric acid and methacrylated chitosan were added to N,N-dimethylformamide, then EDC and NHS were added, and the mixture was reacted at 30°C and a stirring rate of 300 r / min for 6 h. After the reaction, the mixture was purified by dialysis for 36 h, and then freeze-dried to obtain caffeoyl tartaric acid-grafted CSMA. The mass ratio of caffeoyl tartaric acid to methacrylated chitosan was 1:3.5, and the molar ratio of EDC, NHS and caffeoyl tartaric acid was 1.2:1.2:1.

[0045] The aldehyde-modified diallyl tartaramide is prepared by the following steps: p-formylbenzoic acid and N,N'-diallyl-L-tartaramide are mixed, dissolved in anhydrous ethanol, and then p-toluenesulfonic acid is added. The mixture is reacted at 70°C under reflux for 4 hours. After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture is purified by recrystallization and dried to obtain aldehyde-modified diallyl tartaramide. The molar ratio of p-formylbenzoic acid to N,N'-diallyl-L-tartaramide is 1:1.3, and the amount of p-toluenesulfonic acid is 1.2% of the total mass of the reactants p-formylbenzoic acid and N,N'-diallyl-L-tartaramide.

[0046] The boric acid-grafted GelMA was prepared by the following steps: methacrylamide gelatin was dissolved in a phosphate buffer solution at pH 7.4 to prepare a solution; p-bromophenylboronic acid and triethylamine were added; the mixture was stirred and reacted at 40°C under nitrogen protection for 7 hours; after the reaction was completed, the mixture was centrifuged to remove impurities, dialyzed for 48 hours, and freeze-dried to obtain boric acid-grafted GelMA; wherein the mass concentration of the methacrylamide gelatin in the phosphate buffer solution was 8%, the molar ratio of methacrylamide gelatin to p-bromophenylboronic acid was 1:1.0, and the amount of triethylamine used was twice the molar amount of p-bromophenylboronic acid.

[0047] A method for preparing a wound healing dressing for postoperative care of tumor patients includes the following steps:

[0048] (1) Place 90% of the total mass of purified water in a 35°C constant temperature water bath, add boric acid-grafted GelMA and caffeoyl tartaric acid-grafted CSMA, stir until completely dissolved, add glycerol, and continue stirring for 20 min to obtain a mixed mother liquor.

[0049] (2) Add aldehyde-modified diallyl tartaramide to the mixed mother liquor, adjust the pH of the system to 8.5, and stir at 40°C for 40 min to form preliminary cross-linking;

[0050] (3) Continue to add sodium alginate and catechin, stir evenly, add 2-hydroxy-2-methyl-1-phenyl-1-propanone, the amount of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 0.5% of the total mass of the system, purge with nitrogen gas to remove oxygen for 15 min, and irradiate with ultraviolet light with a wavelength of 365 nm for 20 min to carry out photo-initiated crosslinking;

[0051] (4) Dissolve ferric chloride and calcium chloride in the remaining deionized water, slowly add them to the above system, stir for 30 min, and finally pour the cross-linking system into the mold, place it in a vacuum drying oven at 45℃ and dry for 16 h. After demolding, cut it into the required size, and after sterilization, the wound recovery dressing for postoperative care of tumors is obtained.

[0052] Example 3

[0053] A wound healing dressing for postoperative care of tumor patients and its preparation method

[0054] The wound healing dressing for post-tumor surgery care comprises the following components in parts by weight: 35 parts boric acid-grafted GelMA, 20 parts caffeoyl tartaric acid-grafted CSMA, 10 parts aldehyde-modified diallyl tartaramide, 7.5 parts sodium alginate, 3.5 parts catechin, 0.75 parts ferric chloride, 2 parts calcium chloride, 90 parts purified water, and 3 parts glycerin.

[0055] The caffeoyl tartaric acid-grafted CSMA was prepared by the following steps: caffeoyl tartaric acid and methacrylated chitosan were added to N,N-dimethylformamide, then EDC and NHS were added, and the mixture was reacted at 27.5°C and a stirring rate of 250 r / min for 5 h. After the reaction was completed, the mixture was purified by dialysis for 30 h, and then freeze-dried to obtain caffeoyl tartaric acid-grafted CSMA. The mass ratio of caffeoyl tartaric acid to methacrylated chitosan was 1:3, and the molar ratio of EDC, NHS and caffeoyl tartaric acid was 1.2:1.2:1.

[0056] The aldehyde-modified diallyl tartaramide is prepared by the following steps: p-formylbenzoic acid and N,N'-diallyl-L-tartaramide are mixed, dissolved in anhydrous ethanol, and then p-toluenesulfonic acid is added. The mixture is reacted at 65°C under reflux for 3.5 h. After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture is purified by recrystallization and dried to obtain aldehyde-modified diallyl tartaramide. The molar ratio of p-formylbenzoic acid to N,N'-diallyl-L-tartaramide is 1:1.2, and the amount of p-toluenesulfonic acid is 1.0% of the total mass of the reactants p-formylbenzoic acid and N,N'-diallyl-L-tartaramide.

[0057] The boric acid-grafted GelMA was prepared by the following steps: methacrylamide gelatin was dissolved in a phosphate buffer solution at pH 7.4 to prepare a solution; p-bromophenylboronic acid and triethylamine were added; the mixture was stirred and reacted at 37.5°C under nitrogen protection for 6 hours; after the reaction was completed, the mixture was centrifuged to remove impurities, dialyzed for 48 hours, and freeze-dried to obtain boric acid-grafted GelMA; wherein the mass concentration of the methacrylamide gelatin in the phosphate buffer solution was 6.5%, the molar ratio of methacrylamide gelatin to p-bromophenylboronic acid was 1:0.9, and the amount of triethylamine used was 1.75 times the molar amount of p-bromophenylboronic acid.

[0058] A method for preparing a wound healing dressing for postoperative care of tumor patients includes the following steps:

[0059] (1) Place 90% of the total mass of purified water in a 32.5℃ constant temperature water bath, add boric acid grafted GelMA and caffeoyl tartaric acid grafted CSMA, stir until completely dissolved, add glycerol, and continue stirring for 17.5 min to obtain a mixed mother liquor.

[0060] (2) Add aldehyde-modified diallyl tartaramide to the mixed mother liquor, adjust the pH of the system to 8.25, and stir at 37.5℃ for 35 min to form preliminary cross-linking;

[0061] (3) Continue to add sodium alginate and catechin, stir evenly, add 2-hydroxy-2-methyl-1-phenyl-1-propanone, the amount of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 0.4% of the total mass of the system, purge with nitrogen gas to remove oxygen for 12.5 min, and irradiate with ultraviolet light with a wavelength of 365 nm for 17.5 min to carry out photo-initiated crosslinking;

[0062] (4) Dissolve ferric chloride and calcium chloride in the remaining deionized water and slowly add them to the above system. Stir for 25 minutes. Finally, pour the cross-linking system into a mold and dry it in a vacuum drying oven at 42.5℃ for 14 hours. After demolding, cut it into the required size and sterilize it to obtain the wound recovery dressing for postoperative care of tumors.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 3 is that no aldehyde-modified diallyl tartaramide component was added; otherwise, they are the same as in Example 3.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 3 is that ungrafted methacrylated chitosan was used instead of caffeoyl tartaric acid grafted CSMA; otherwise, they are the same as in Example 3.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 3 is that ungrafted methacrylamide gelatin was used instead of boric acid-grafted GelMA; otherwise, they are the same as in Example 3.

[0069] Results Analysis

[0070] Test Example 1: Mechanical Property Test

[0071] Test objective: To verify that the dressing prepared in this invention has an interpenetrating network structure constructed through multiple cross-linked networks, which gives it both high strength and good toughness.

[0072] Testing standards:

[0073] Refer to GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets".

[0074] Detailed testing process:

[0075] The dressings prepared in Examples 1-3 and Comparative Examples 1-3 were cut into standard dumbbell-shaped specimens (total length ≥75mm, gauge length 25mm, width 6mm). Five parallel samples were prepared for each type of specimen.

[0076] The sample was placed in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 24 hours to adjust its condition.

[0077] The specimen is mounted on the fixture of the universal testing machine, and the initial distance of the fixture is set to the gauge length (25 mm).

[0078] Set the stretching speed to 50 mm / min.

[0079] Start the testing machine and stretch the specimen at a constant speed until it breaks. The testing machine automatically records the force-displacement curve during the stretching process, recording the maximum force and the displacement at fracture, thereby calculating the tensile strength and elongation at break.

[0080] Calculate the mean and standard deviation of the five parallel samples in each group.

[0081] The test results are shown in Table 1.

[0082] Table 1 Comparison of Test Results of Mechanical Properties of Dressings

[0083] sample Tensile strength (MPa) Elongation at break (%) Example 1 2.8±0.2 185±15 Example 2 3.2±0.3 210±18 Example 3 3.5±0.2 240±20 Comparative Example 1 1.9±0.2 85±10 Comparative Example 2 2.2±0.2 160±12 Comparative Example 3 2.5±0.2 170±14

[0084] Table 1 shows that Examples 1-3 all exhibited high tensile strength and elongation at break. Compared to Example 3, Comparative Example 1, lacking aldehyde-modified diallyl tartrate, lost dynamic imine bonds and some photopolymerization crosslinking points, resulting in an incomplete network structure, significantly reduced mechanical strength, and a substantial decrease in elongation at break, making the material more brittle. Comparative Example 2, using ungrafted CSMA, lacked catechol groups, leading to weakened coordination with iron ions and reduced energy dissipation, thus its toughness and strength were slightly lower than Example 3. Comparative Example 3, using ungrafted GelMA, lacked borate groups, similarly weakening coordination with iron ions and potential dynamic borate ester bonds, resulting in lower mechanical properties than Example 3. The results indicate that this invention, through a synergistic enhancement via multiple crosslinking mechanisms, endows the dressing with excellent mechanical properties.

[0085] Test Example 2: Antibacterial Performance Test

[0086] Test objective: To verify the antibacterial mechanism of the dressing of the present invention (cationic chitosan, catechin, iron ion-based Fenton reaction) and its inhibitory effect on common pathogens, especially its inhibitory ability on drug-resistant bacteria.

[0087] Testing standards:

[0088] Refer to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Vibration method".

[0089] Detailed testing process:

[0090] Bacterial strain preparation: Staphylococcus aureus (ATCC 6538) and methicillin-resistant Staphylococcus aureus (MRSA, ATCC 43300) were selected as test strains. The strains were inoculated into LB broth and incubated at 37°C for 18 hours. The bacterial culture was then diluted to 1×10⁻⁶ with sterile physiological saline. 6 CFU / mL.

[0091] Sample preparation: Cut the dressings from Examples 1-3 and Comparative Examples 1-3 into 2cm × 2cm squares. All samples and controls were autoclaved at 121℃ for 20 min.

[0092] Shaking contact: Add 70 mL of PBS buffer and 10 mL of bacterial suspension to a sterile Erlenmeyer flask. Add sterile dressing samples separately, and set up a blank control with only bacterial suspension and no dressing. Place the Erlenmeyer flask in a shaker and incubate with shaking at 37°C and 150 rpm for 24 h.

[0093] Viable cell count: After culturing, take 1 mL of culture medium and perform 10-fold serial dilutions with PBS. Take 100 μL of the appropriately diluted bacterial solution and spread it evenly on LB agar plates, with 3 replicates for each dilution. Incubate the plates at 37°C for 24 h.

[0094] Colony counting: Select plates with colony counts between 30 and 300 for counting.

[0095] Antibacterial rate calculation: The antibacterial rate is calculated according to the formula.

[0096] The test results are shown in Table 2.

[0097] Table 2 Comparison of Antibacterial Performance Test Results of Dressings

[0098] sample Antibacterial rate against S. aureus (%) Antibacterial rate against MRSA (%) Example 1 98.5±1.2 96.5±1.5 Example 2 99.2±0.8 97.8±1.1 Example 3 99.6±0.5 98.5±0.9 Comparative Example 1 90.2±2.1 86.3±2.5 Comparative Example 2 85.5±2.5 78.5±3.0 Comparative Example 3 92.5±1.8 88.5±2.2

[0099] Table 2 shows that Examples 1-3 exhibited excellent antibacterial activity against both strains, with inhibition rates all above 96%. Comparative Example 1 showed slightly weaker antibacterial activity, possibly due to network defects caused by the lack of aldehyde-modified diallyl tartrate, which may have affected the release of the small-molecule antibacterial component. Comparative Example 2 showed significantly reduced antibacterial activity because it used ungrafted CSMA, reducing the cationic and catechol groups on the CSMA and weakening the antibacterial properties of the CSMA itself and its subsequent synergistic antibacterial effect with iron ions. Comparative Example 3 also showed lower antibacterial activity than Example 3 because the lack of boric acid grafting affected the coordination stability of iron ions, potentially weakening the antibacterial effect produced by the Fenton-like reaction. The results indicate that the synergistic effect of the multiple antibacterial mechanisms of this invention significantly enhances the anti-infection ability of the dressing, especially showing a strong inhibitory effect against drug-resistant MRSA.

[0100] Test Example 3: In Vitro Hemostatic Performance Test

[0101] Test objective: To verify the astringent effect of polyphenols (catechins, caffeoyl tartaric acid) in the dressing of this invention and the physical hemostatic function of sodium alginate / calcium ions.

[0102] Testing standards:

[0103] Refer to YY / T 1765-2020 "Tissue-engineered medical device products collagen - Part 1: Evaluation of hemostatic properties of collagen".

[0104] Detailed testing process:

[0105] Sample preparation: Cut the dressings of Examples 1-3 and Comparative Examples 1-3 into 1cm × 1cm square samples. Set up 3 parallel samples for each group.

[0106] Activated partial thromboplastin time (APTT) assay:

[0107] a. Place the dressing sample in a test tube, add 0.1 mL of APTT reagent, and preheat at 37°C for 5 min.

[0108] b. Add 0.1 mL of fresh anticoagulated rabbit plasma and continue preheating at 37°C for 3 min.

[0109] c. Add 0.1 mL of 0.025 MCaCl2 solution and immediately record the coagulation time detected by the coagulation analyzer.

[0110] Prothrombin time (PT) measurement:

[0111] a. Place the dressing sample in a test tube, add 0.1 mL of fresh anticoagulated rabbit plasma, and preheat at 37°C for 3 min.

[0112] b. Add 0.2 mL of PT reagent and immediately record the coagulation time detected by the coagulation analyzer.

[0113] Blank control: The above tests were performed using an equal volume of physiological saline instead of the dressing sample.

[0114] Data recording methods and calculation methods:

[0115] Record the APTT and PT values ​​directly (unit: seconds). The smaller the APTT and PT values, the better the hemostasis effect.

[0116] The test results are shown in Table 3.

[0117] Table 3 Comparison of In Vitro Hemostatic Performance Test Results of Dressings

[0118] sample APTT (seconds) PT (seconds) Blank control 32.5±1.5 14.2±0.8 Example 1 20.5±1.2 11.5±0.6 Example 2 19.8±1.0 11.2±0.5 Example 3 19.5±0.9 10.8±0.4 Comparative Example 1 27.5±1.5 13.0±0.7 Comparative Example 2 24.5±1.3 12.5±0.7 Comparative Example 3 23.8±1.2 12.2±0.6

[0119] Table 3 shows that the APTT and PT values ​​of all example groups were significantly lower than those of the blank control group, indicating that the dressing has good hemostatic function. Comparative Example 1 showed relatively poor hemostatic effect because it did not contain aldehyde-modified diallyl tartaramide, resulting in a denser network structure, which may have affected the initial release of polyphenols, thus weakening its astringent hemostatic effect. Comparative Examples 2 and 3 also showed lower hemostatic effects than Example 3, respectively, due to the lack of caffeoyl tartaric acid grafting and boric acid grafting, which affected the dynamic balance between polyphenols and iron ions, leading to a reduction in the initial rapid release of active ingredients. The results indicate that the polyphenols and sodium alginate / calcium ions in the dressing of this invention work synergistically to effectively promote coagulation, shorten coagulation time, and achieve efficient hemostasis.

[0120] Test Example 4: Active Ingredient Release Behavior Test

[0121] Test objective: To verify the sustained and slow release of catechins in the dressing of this invention, and to prove that it achieves controlled release and long-lasting care.

[0122] Test standard: Refer to the "Release Rate Determination Method" in General Chapter 0931 of Part IV of the 2020 edition of the Chinese Pharmacopoeia.

[0123] Detailed testing process:

[0124] Sample preparation: Cut the dressings of Examples 1-3 and Comparative Examples 1-3 into circular pieces with a diameter of 2 cm and weigh them.

[0125] Release medium: Prepare PBS buffer solution with pH 7.4 (simulating normal physiological environment) and PBS buffer solution with pH 6.5 (simulating slightly acidic environment of wound).

[0126] Release experiment: Place the sample in a 50 mL centrifuge tube, add 20 mL of release medium, and place in a constant temperature shaking incubator at 37 °C and 100 rpm.

[0127] Sampling and replenishment: Take 1 mL of release solution at preset time points (1 h, 168 h) and immediately replenish with 1 mL of fresh release medium.

[0128] Content determination: The concentration of catechins in the release solution was determined by HPLC. Chromatographic conditions: C18 column, mobile phase: methanol-0.1% phosphoric acid aqueous solution, gradient elution, detection wavelength: 280 nm.

[0129] Calculation: Calculate the cumulative release amount (µg / mg dressing) at each time point based on the standard curve.

[0130] The test results are shown in Table 4.

[0131] Table 4 Comparison of Test Results for Release Behavior of Active Ingredients in Dressings

[0132] sample pH 7.4 / 1h pH 7.4 / 168h pH 6.5 / 1h pH 6.5 / 168h Example 1 1.85±0.12 3.15±0.18 1.98±0.14 3.51±0.20 Example 2 1.82±0.15 3.18±0.22 1.95±0.16 3.55±0.24 Example 3 1.95±0.10 3.12±0.15 2.01±0.12 3.80±0.18 Comparative Example 1 1.92±0.14 2.55±0.20 1.95±0.15 2.72±0.22 Comparative Example 2 2.08±0.13 2.48±0.19 2.01±0.14 2.65±0.21 Comparative Example 3 1.99±0.12 2.50±0.18 2.03±0.13 2.68±0.20

[0133] As shown in Table 4, in all examples and comparative examples, catechins achieved a high cumulative release within 1 hour, continued to be released slowly over the following 7 days, and exhibited a high cumulative release after 168 hours. While the comparative example also achieved a high cumulative release within 1 hour, it failed to achieve sustained release in subsequent stages. This indicates that the catechins in the dressings have immediate antioxidant and astringent hemostatic effects, as well as a long-lasting sustained-release effect. The release rate at a slightly acidic pH of 6.5 is slightly higher than at pH 7.4, which is beneficial for releasing more active ingredients in the slightly acidic environment of the wound.

[0134] Test Example 5: Cell Compatibility and Proliferation Assay (CCK-8 assay)

[0135] Test objective: To verify that the dressing of the present invention has good biocompatibility and can promote the adhesion and proliferation of cells (such as fibroblasts) and optimize the healing microenvironment.

[0136] Test standard: Refer to GB / T 16886.5-2017 "Biological evaluation of medical devices - Part 5: In vitro cytotoxicity test".

[0137] Detailed testing process:

[0138] Preparation of extract: The dressings from Examples 1-3 and Comparative Examples 1-3 were cut into 1cm × 1cm pieces and immersed in DMEM complete medium at a ratio of 0.2g / mL. The mixture was then extracted at 37℃ in a 5% CO2 incubator for 24 hours to obtain a 100% extract. The extracts were then diluted with medium to prepare 50% and 10% extracts.

[0139] Cell seeding: HSF cells in logarithmic growth phase were digested and seeded at a density of 5 × 10³ cells / well in 96-well plates, 100 μL per well. Cells were cultured at 37°C in a 5% CO2 incubator for 24 h to allow cell adhesion.

[0140] Sample addition: Remove the old culture medium from the wells and add different concentrations of extraction solution (100%, 50%, 10%), with 6 replicates per group. Also set up a negative control (culture medium without samples) and a blank control (no cells, culture medium only).

[0141] Incubation: Continue incubation for 24 hours and 72 hours.

[0142] CCK-8 assay: At each time point, 10 μL of CCK-8 solution was added to each well and incubated in an incubator for 2 hours. The absorbance (OD value) at 450 nm was measured using a microplate reader.

[0143] Cell viability calculation: Cell viability (%) = (OD sample - OD blank) / (OD negative control - OD blank) × 100%.

[0144] The test results are shown in Table 5.

[0145] Table 5 Comparison of Dressing Cell Compatibility and Proliferation Test Results

[0146] sample Cell viability (%) negative control 100 Example 1 108±5 Example 2 112±6 Example 3 120±5 Comparative Example 1 95±4 Comparative Example 2 102±5 Comparative Example 3 98±5

[0147] As shown in the table above, the cell viability of Examples 1-3 was greater than 100%, indicating that the dressing was non-cytotoxic and could promote cell proliferation, with Example 3 showing the most significant proliferation-promoting effect. The cell viability of Comparative Examples 1, 2, and 3 was lower than that of Example 3. Comparative Example 1 may have had a denser network structure, limiting the exposure of active sites such as the RGD sequence that promotes cell adhesion. Comparative Examples 2 and 3, respectively, lacked caffeoyl tartaric acid grafting and boric acid grafting, resulting in decreased antioxidant and anti-inflammatory activities, and slightly poorer network structure integrity, affecting the cell growth microenvironment. The results indicate that the dressing of the present invention has good biocompatibility and can effectively promote cell adhesion and proliferation through the RGD sequence of GelMA and the healing-promoting properties of CSMA, which is beneficial to wound tissue regeneration.

[0148] Test Example 6: Test on Wound Healing Effect in Rats

[0149] Test objective: To verify the wound-healing effect of the dressing of the present invention at the wound site by constructing a skin infection wound model in rats.

[0150] Detailed testing process:

[0151] Animal model: 32 male SD rats (weighing 200-250g) aged 6-8 weeks were randomly divided into 4 groups: Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3, with 8 rats in each group.

[0152] Modeling: After anesthesia, a circular wound with a diameter of 10 mm was created on the back of the rat.

[0153] Treatment: Cut each dressing to a size slightly larger than the wound, place it over the wound, and secure it with sterile gauze and medical tape. Change the dressing every 2 days.

[0154] Observation and recording: On postoperative days 0, 3, 7, 10 and 14, the wounds of each group were photographed and the presence of infection, suppuration and other conditions were recorded.

[0155] As can be seen from the figure, the wound healing rate of Group 3 in Example 3 was significantly higher than that of the other groups at all time points, and it was basically completely healed by day 14, with a relatively smooth wound. In contrast, the comparative groups 3 showed scab formation, pus discharge, uneven surface, and incomplete wound healing during the experiment. This indicates that the method can significantly accelerate wound healing, improve healing quality, and effectively control infection and inflammation.

[0156] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0157] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown are only one of the embodiments of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A wound healing dressing for postoperative care of tumor patients, characterized in that: The product comprises the following components in parts by weight: 30-40 parts of boric acid-grafted GelMA, 15-25 parts of caffeoyl tartaric acid-grafted CSMA, 8-12 parts of aldehyde-modified diallyl tartaramide, 5-10 parts of sodium alginate, 2-5 parts of catechin, 0.5-1 part of ferric chloride, 1-3 parts of calcium chloride, 80-100 parts of purified water, and 2-4 parts of glycerol; wherein the boric acid-grafted GelMA is obtained by reacting p-bromophenylboronic acid with methacrylamide gelatin, the caffeoyl tartaric acid-grafted CSMA is obtained by reacting caffeoyl tartaric acid with methacrylamide chitosan, and the aldehyde-modified diallyl tartaramide is obtained by reacting p-formylbenzoic acid with N,N'-diallyl-L-tartaramide.

2. The wound healing dressing for postoperative care of tumor patients according to claim 1, characterized in that: The caffeoyl tartaric acid-grafted CSMA is prepared by the following steps: caffeoyl tartaric acid and methacrylated chitosan are added to N,N-dimethylformamide, then EDC and NHS are added, and the reaction is carried out at 25-30℃ and a stirring rate of 200-300 r / min for 4-6 h. After the reaction is completed, the mixture is purified by dialysis for 24-36 h, and then freeze-dried to obtain caffeoyl tartaric acid-grafted CSMA.

3. The wound healing dressing for postoperative care of tumor patients according to claim 2, characterized in that: The mass ratio of caffeoyl tartaric acid to methacrylated chitosan is 1:2.5-3.5, and the molar ratio of EDC, NHS to caffeoyl tartaric acid is 1.2:1.2:

1.

4. The wound healing dressing for postoperative care of tumor patients according to claim 1, characterized in that: The aldehyde-modified diallyl tartaramide is prepared by the following steps: p-formylbenzoic acid and N,N'-diallyl-L-tartaramide are mixed, dissolved in anhydrous ethanol, and then p-toluenesulfonic acid is added. The mixture is reacted at 60-70°C under reflux for 3-4 hours. After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture is purified by recrystallization and dried to obtain aldehyde-modified diallyl tartaramide.

5. The wound healing dressing for postoperative care of tumor patients according to claim 4, characterized in that: The molar ratio of p-formylbenzoic acid to N,N'-diallyl-L-tartaramide is 1:1.1-1.3, and the amount of p-toluenesulfonic acid used accounts for 0.8-1.2% of the total mass of the reactants p-formylbenzoic acid and N,N'-diallyl-L-tartaramide.

6. The wound healing dressing for postoperative care of tumor patients according to claim 1, characterized in that: The boric acid-grafted GelMA was prepared by the following steps: methacrylamide gelatin was dissolved in phosphate buffer solution at pH 7.4 to prepare a solution, p-bromophenylboronic acid and triethylamine were added, and the mixture was stirred and reacted at 35-40℃ under nitrogen protection for 5-7 hours. After the reaction was completed, the mixture was centrifuged to remove impurities, dialyzed for 48 hours, and freeze-dried to obtain boric acid-grafted GelMA.

7. The wound healing dressing for postoperative care of tumor patients according to claim 6, characterized in that: The mass concentration of the methacrylamide gelatin in the phosphate buffer solution is 5-8%, the molar ratio of methacrylamide gelatin to p-bromophenylboronic acid is 1:0.8-1.0, and the amount of triethylamine used is 1.5-2 times the molar amount of p-bromophenylboronic acid.

8. A method for preparing a wound healing dressing for postoperative care of tumor patients according to any one of claims 1-7, characterized in that: Includes the following steps: (1) Place 90% of the total mass of purified water in a constant temperature water bath at 30-35℃, add boric acid grafted GelMA and caffeoyl tartaric acid grafted CSMA, stir until completely dissolved, add glycerol, and continue stirring for 15-20 min to obtain a mixed mother liquor. (2) Add aldehyde-modified diallyl tartaramide to the mixed mother liquor, adjust the pH of the system to 8.0-8.5, and stir at 35-40℃ for 30-40 min to form preliminary cross-linking; (3) Continue to add sodium alginate and catechin, stir evenly, add 2-hydroxy-2-methyl-1-phenyl-1-propanone, purge with nitrogen to remove oxygen for 10-15 min, and irradiate with ultraviolet light with a wavelength of 365 nm for 15-20 min to carry out photo-initiated crosslinking. (4) Dissolve ferric chloride and calcium chloride in the remaining deionized water and slowly add them to the above system. Stir for 20-30 minutes. Finally, pour the cross-linking system into a mold and dry it in a vacuum drying oven at 40-45℃ for 12-16 hours. After demolding, cut it into the required size and sterilize it to obtain the wound recovery dressing for postoperative care of tumors.

9. The method for preparing the wound healing dressing for postoperative care of tumor patients according to claim 8, characterized in that: The amount of 2-hydroxy-2-methyl-1-phenyl-1-propanone used is 0.3-0.5% of the total mass of the system.

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