A postoperative tumor care wound dressing and a method of making the same

Abstract

The application discloses a kind of wound dressings for postoperative care of tumor and preparation method thereof, belong to nursing dressing technical field.The dressing is made of glucose sulfatase functionalized chitosan and drug-loaded bacterial cellulose composite.Preparation, first Fe3O4 Nanoparticle is reacted with dopamine to obtain polydopamine ferrite, then with aldehyde group chitosan reaction to construct magnetic functionalized carrier, by adsorption fixed glucose sulfatase;While glucosinolate extract and oleanolic acid are loaded in bacterial cellulose;Finally, the two are compounded, and the dressing is obtained.The application utilizes the structure of Schiff base and catechol to realize the strong adhesion of wound surface, releases active ingredients in situ through enzymatic reaction, has multiple effects of antibacterial, anti-inflammatory, antioxidant and healing, and has good biocompatibility, can effectively solve the problems of wound infection, delayed healing and dressing fixation difficulty after tumor operation, and significantly improves the nursing effect.

Description

Technical Field

[0001] This invention belongs to the field of nursing dressing technology, and in particular relates to a wound dressing for postoperative care of tumors and its preparation method. Background Technology

[0002] Cancer, especially malignant tumors, has become a major public health problem posing a serious threat to human life and health worldwide. Currently, for most solid tumors, surgical resection remains the most direct and effective first-line treatment. However, the quality of postoperative wound care directly affects the patient's postoperative recovery process, complication rate, and even long-term prognosis. Clinical practice and research show that postoperative wound healing in cancer faces a more complex physiological and pathological environment than in general surgical trauma. Cancer resection surgery often involves large wound areas and extensive tissue dissection, resulting in significant postoperative wound exudate, which easily leads to complications such as wound infection and bleeding. Furthermore, cancer patients often suffer from tumor-related malnutrition and weakened immune function, and may require early adjuvant radiotherapy or chemotherapy after surgery. These factors severely interfere with fibroblast proliferation and collagen synthesis, leading to significantly impaired wound healing ability. Wounds often remain in a state of prolonged non-healing, and may even develop into chronic, intractable wounds.

[0003] Traditional dressings widely used in clinical practice, such as gauze and cotton pads, primarily function only to passively absorb exudate and protect the wound. They have inherent drawbacks, including easy adhesion to newly formed granulation tissue, secondary damage during dressing changes, and an inability to provide a moist healing environment. In recent years, various novel functional dressings, such as alginate dressings, hydrocolloid dressings, hydrogel dressings, and silver-containing antibacterial dressings, have been applied, but they still cannot fully meet the special nursing needs of post-tumor surgery wounds. Ordinary dressings cannot achieve long-lasting and secure adhesion; most existing dressings have limited functions and lack the ability to regulate the bioactivity of the wound microenvironment after tumor surgery.

[0004] Existing basic research has shown that glucosinolates and their hydrolysis products, particularly sulforaphane, abundant in cruciferous plants (such as broccoli, cabbage, and mustard greens) have significant effects in inducing tumor cell apoptosis, inhibiting histone deacetylase activity, and regulating the Nrf2 antioxidant pathway, exhibiting potential anti-tumor recurrence and anti-inflammatory activities. However, glucosinolates themselves are stable and must be hydrolyzed by glucosinolates to generate biologically active isothiocyanates. Directly mixing enzymes and substrates to prepare dressings is prone to rapid decline in enzyme activity during storage and use, or inaccurate spatial and temporal matching between substrates and enzymes, leading to uncontrollable release of active ingredients and low utilization rates, thus limiting their clinical application.

[0005] In conclusion, developing a novel wound dressing that combines strong tissue adhesion, intelligent controlled drug release, and multiple bioactivities is of great importance for improving postoperative wound care in cancer patients, inhibiting inflammatory responses, and promoting healing. Summary of the Invention

[0006] In view of the above situation and to overcome the shortcomings of the prior art, the present invention improves the chitosan and bacterial cellulose components, so that the dressing has functions such as high-efficiency adhesion, controlled drug delivery, enzymatic activation, antibacterial, anti-inflammatory and antioxidant properties.

[0007] To achieve the above objectives, the following technical solution is adopted: On one hand, the present invention provides a method for preparing a wound dressing for post-tumor surgery care, comprising the following steps:

[0008] S1. Fe3O4 nanoparticles were reacted with dopamine hydrochloride to obtain polydopamine ferrite; chitosan was oxidized with sodium periodate to obtain aldehyde-modified chitosan; aldehyde-modified chitosan was dissolved in 0.1M acetate buffer solution at pH 5.5, polydopamine ferrite was added, the mixture was ultrasonically dispersed, heated to 40-50℃, stirred for 6-8 hours, centrifuged, washed, and freeze-dried to obtain polydopamine ferrite functionalized chitosan carrier;

[0009] S2. Dissolve glucosinolate in 50mM phosphate buffer at pH 6.0, add polydopamine ferrite-functionalized chitosan carrier, and shake at 4℃ for 12-16h to adsorb; collect the product by magnetic separation, wash with buffer, and freeze-dry to obtain glucosinolate-loaded functionalized chitosan.

[0010] S3. Dissolve glucosinolate extract and oleanolic acid in a 70% ethanol solution, immerse bacterial cellulose in the solution, soak at room temperature for 30-60 minutes, remove and vacuum dry at 40-50℃ to obtain drug-loaded bacterial cellulose.

[0011] S4. Disperse glucosinolate-functionalized chitosan in deionized water, immerse drug-loaded bacterial cellulose in the dispersion, shake at 4°C for 12-24 hours, remove and freeze-dry to obtain the wound dressing.

[0012] Furthermore, the preparation process of the polydopamine ferrite is as follows: Fe3O4 nanoparticles are ultrasonically dispersed in a 10mM Tris-HCl buffer solution with pH=8.5 to form a uniform dispersion, dopamine hydrochloride is added, and the mixture is stirred at room temperature in the dark for 12-16 hours. The product is separated by magnetic separation, and then washed alternately with deionized water and ethanol until neutral. The product is then dried under vacuum to obtain the polydopamine ferrite.

[0013] Furthermore, the mass ratio of the Fe3O4 nanoparticles, dopamine hydrochloride, and Tris-HCl buffer is 1:0.2-0.4:100-120.

[0014] Furthermore, the preparation process of the aldehyde-modified chitosan is as follows: chitosan is dissolved in an aqueous acetic acid solution with a volume fraction of 1%-2%, stirred until completely dissolved, sodium periodate is added, and the mixture is stirred at 25-30°C in the dark for 4-6 hours. Finally, ethylene glycol is added, and stirring is continued for 30 minutes. The mixture is then dialyzed with deionized water for 48 hours and freeze-dried to obtain the aldehyde-modified chitosan.

[0015] Further, the mass ratio of chitosan, sodium periodate, ethylene glycol, and aqueous acetic acid is 1:0.4-0.6:0.1-0.3:80-120.

[0016] Furthermore, in step S1, the mass ratio of aldehyde-modified chitosan, polydopamine ferrite, and acetate buffer is 1:0.2-0.5:80-120.

[0017] Furthermore, in step S2, the mass ratio of glucosinolates, polydopamine ferrite-functionalized chitosan carrier, and phosphate buffer is 1:5-10:500-1000.

[0018] Furthermore, in step S3, the mass ratio of glucosinolate extract, oleanolic acid, and ethanol solution is 1:0.3-0.5:50-100.

[0019] Furthermore, in step S4, the mass ratio of glucosinolate-loaded functionalized chitosan to deionized water is 1:100-200.

[0020] On the other hand, the present invention provides a wound dressing for postoperative care of tumor patients, which is prepared by the aforementioned method.

[0021] The beneficial effects of this invention are:

[0022] This invention employs an aldehyde-based chitosan and polydopamine ferrite composite to construct a chitosan adhesion system. Active aldehyde groups are introduced onto the chitosan molecular chain through selective oxidation with sodium periodate, forming Schiff base covalent bonds with the polydopamine ferrite. Simultaneously, the polydopamine ferrite surface is rich in catechol structures, which can mimic the strong coordination and hydrogen bonding between bioadhesion proteins and tissues. This endows the dressing with strong adhesion, non-displacement, and non-falling-off properties on moist, exudative postoperative tumor wounds, effectively solving the problems of easy slippage and difficult fixation of traditional dressings, and providing a stable and sealed healing microenvironment for wound repair.

[0023] Immobilizing glucosinolates on a polydopamine ferrite-functionalized chitosan carrier not only protects enzyme activity and improves stability through the mild immobilization effect of polydopamine, but also preserves the porous structure and biocompatibility of the carrier. Glucosinolate extracts and oleanolic acid are loaded onto a bacterial cellulose matrix. After the dressing is applied to the wound, the enzyme and substrate come into full contact under the influence of wound exudate and the tissue microenvironment. Glucosinolates are hydrolyzed, releasing an antibacterial, anti-inflammatory, and healing-promoting system, reducing the risk of local recurrence, and simultaneously inhibiting the inflammatory response of the wound.

[0024] The polydopamine structure in this composite system has excellent antioxidant and free radical scavenging capabilities. It can effectively remove excess reactive oxygen species in the wound microenvironment, reduce the damage of oxidative stress to normal repair cells such as fibroblasts and endothelial cells, protect newly formed tissues in the wound, improve local tissue repair capabilities, and significantly alleviate the problem of delayed healing in cancer patients.

[0025] Chitosan, bacterial cellulose, polydopamine, and glucosinolate extracts all possess good biocompatibility and biodegradability. While exerting antibacterial, anti-inflammatory, and healing-promoting effects, the dressing has low toxicity and minimal irritation to normal tissues, avoiding secondary damage to the wound when changing dressings. It is suitable for the long-term, gentle, and safe nursing needs of tumor postoperative wounds. Attached Figure Description

[0026] Figure 1 Infrared images of unmodified chitosan (a), aldehyde-modified chitosan (b), polydopamine ferrite-functionalized chitosan carrier (c), and glucosinolate-loaded glucosinolate-functionalized chitosan (d) in this invention.

[0027] Figure 2 This is a comparison chart of the adhesion performance test results of the various groups of dressings of the present invention;

[0028] Figure 3 This is a comparison chart of the enzyme activity test results of the various groups of dressings in this invention;

[0029] Figure 4 This is a comparison chart of the antioxidant activity test results of the various groups of dressings in this invention;

[0030] Figure 5 This is a comparison chart of the antibacterial properties test results of the various groups of dressings of the present invention;

[0031] Figure 6 This is a comparison chart of the cytotoxicity test results of the various groups of dressings in this invention;

[0032] Figure 7 This is a comparison chart showing the wound healing ability characterization results of the dressings prepared in Example 3 and Comparative Examples 1-2 of the present invention.

[0033] 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

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Example 1

[0038] A method for preparing a wound dressing for postoperative care of tumor patients includes the following steps:

[0039] S1. Fe3O4 nanoparticles were ultrasonically dispersed in a 10mM Tris-HCl buffer solution (pH 8.5) to form a uniform dispersion. Dopamine hydrochloride was added, and the mixture was stirred at room temperature in the dark for 12 hours. The product was separated by magnetic separation, and then washed alternately with deionized water and ethanol until neutral. The product was then vacuum dried to obtain polydopamine ferrite. The mass ratio of Fe3O4 nanoparticles, dopamine hydrochloride, and Tris-HCl buffer solution was 1:0.2:100. Chitosan was dissolved in a 1% (v / v) acetic acid aqueous solution and stirred until completely dissolved. Sodium periodate was added, and the mixture was stirred at 25°C in the dark for 4 hours. Ethylene glycol was then added, and stirring continued for 30 min. The mixture was dialyzed against deionized water for 48 h, and then freeze-dried to obtain aldehyde-modified chitosan. The mass ratio of chitosan, sodium periodate, ethylene glycol, and acetic acid aqueous solution was 1:0.4:0.1:80. The aldehyde-modified chitosan was dissolved in a 0.1 M acetate buffer solution (pH 5.5), polydopamine ferrite was added, and the mixture was ultrasonically dispersed. The mixture was heated to 40 °C, stirred for 6 h, centrifuged, washed, and freeze-dried to obtain a polydopamine ferrite-functionalized chitosan carrier. The mass ratio of aldehyde-modified chitosan, polydopamine ferrite, and acetate buffer solution was 1:0.2:80.

[0040] S2. Dissolve glucosinolate in 50 mM phosphate buffer (pH 6.0), add polydopamine ferrite-functionalized chitosan carrier, and shake at 4 °C for 12 h to adsorb. Collect the product by magnetic separation, wash with buffer, and freeze-dry to obtain glucosinolate-loaded functionalized chitosan. The mass ratio of glucosinolate, polydopamine ferrite-functionalized chitosan carrier, and phosphate buffer is 1:5:500.

[0041] S3. Dissolve glucosinolate extract and oleanolic acid in a 70% ethanol solution, immerse bacterial cellulose in the solution, soak at room temperature for 30 min, remove and vacuum dry at 40℃ to obtain drug-loaded bacterial cellulose; wherein the mass ratio of glucosinolate extract, oleanolic acid and ethanol solution is 1:0.3:50.

[0042] S4. Disperse glucosinolate-functionalized chitosan in deionized water, immerse drug-loaded bacterial cellulose in the dispersion, shake at 4°C for 12 hours, remove and freeze-dry to obtain the wound dressing; wherein the mass ratio of glucosinolate-functionalized chitosan to deionized water is 1:100.

[0043] Example 2

[0044] A method for preparing a wound dressing for postoperative care of tumor patients includes the following steps:

[0045] S1. Fe3O4 nanoparticles were ultrasonically dispersed in a 10mM Tris-HCl buffer solution (pH 8.5) to form a uniform dispersion. Dopamine hydrochloride was added, and the mixture was stirred at room temperature in the dark for 16 hours. The product was separated by magnetic separation, and then washed alternately with deionized water and ethanol until neutral. The product was then vacuum dried to obtain polydopamine ferrite. The mass ratio of Fe3O4 nanoparticles, dopamine hydrochloride, and Tris-HCl buffer solution was 1:0.4:120. Chitosan was dissolved in a 2% (v / v) acetic acid aqueous solution and stirred until completely dissolved. Sodium periodate was added, and the mixture was stirred at 30°C in the dark for 6 hours. Finally... Ethylene glycol was added, and stirring was continued for 30 min. Dialysis with deionized water was performed for 48 h, followed by freeze-drying to obtain aldehyde-modified chitosan. The mass ratio of chitosan, sodium periodate, ethylene glycol, and acetic acid aqueous solution was 1:0.6:0.3:120. The aldehyde-modified chitosan was dissolved in a 0.1 M acetate buffer solution (pH 5.5), polydopamine ferrite was added, and the mixture was ultrasonically dispersed. The mixture was heated to 50 °C, stirred for 8 h, centrifuged, washed, and freeze-dried to obtain a polydopamine ferrite-functionalized chitosan carrier. The mass ratio of aldehyde-modified chitosan, polydopamine ferrite, and acetate buffer solution was 1:0.5:120.

[0046] S2. Dissolve glucosinolate in 50 mM phosphate buffer (pH 6.0), add polydopamine ferrite-functionalized chitosan carrier, and shake at 4 °C for 16 h to adsorb. Collect the product by magnetic separation, wash with buffer, and freeze-dry to obtain glucosinolate-loaded functionalized chitosan. The mass ratio of glucosinolate, polydopamine ferrite-functionalized chitosan carrier, and phosphate buffer is 1:10:1000.

[0047] S3. Dissolve glucosinolate extract and oleanolic acid in a 70% ethanol solution, immerse bacterial cellulose in the solution, soak at room temperature for 60 min, remove and vacuum dry at 50℃ to obtain drug-loaded bacterial cellulose; wherein the mass ratio of glucosinolate extract, oleanolic acid and ethanol solution is 1:0.5:100.

[0048] S4. Disperse glucosinolate-functionalized chitosan in deionized water, immerse drug-loaded bacterial cellulose in the dispersion, shake at 4°C for 24 hours, remove and freeze-dry to obtain the wound dressing; wherein the mass ratio of glucosinolate-functionalized chitosan to deionized water is 1:200.

[0049] Example 3

[0050] A method for preparing a wound dressing for postoperative care of tumor patients includes the following steps:

[0051] S1. Fe3O4 nanoparticles were ultrasonically dispersed in a 10mM Tris-HCl buffer solution (pH 8.5) to form a uniform dispersion. Dopamine hydrochloride was added, and the mixture was stirred at room temperature in the dark for 14 hours. The product was separated by magnetic separation, and then washed alternately with deionized water and ethanol until neutral. The product was then vacuum dried to obtain polydopamine ferrite. The mass ratio of Fe3O4 nanoparticles, dopamine hydrochloride, and Tris-HCl buffer solution was 1:0.3:110. Chitosan was dissolved in a 1.5% (v / v) acetic acid aqueous solution and stirred until completely dissolved. Sodium periodate was added, and the mixture was stirred at 28°C in the dark for 5 hours. Ethylene glycol was then added, and stirring continued for 30 min. The mixture was dialyzed against deionized water for 48 h, and then freeze-dried to obtain aldehyde-modified chitosan. The mass ratio of chitosan, sodium periodate, ethylene glycol, and acetic acid aqueous solution was 1:0.5:0.2:100. The aldehyde-modified chitosan was dissolved in a 0.1 M acetate buffer solution (pH 5.5), polydopamine ferrite was added, and the mixture was ultrasonically dispersed. The mixture was heated to 45 °C, stirred for 7 h, centrifuged, washed, and freeze-dried to obtain a polydopamine ferrite-functionalized chitosan carrier. The mass ratio of aldehyde-modified chitosan, polydopamine ferrite, and acetate buffer solution was 1:0.35:100.

[0052] S2. Glucosamine thioglycoside was dissolved in 50 mM phosphate buffer at pH 6.0, and polydopamine ferrite-functionalized chitosan carrier was added. The mixture was shaken and adsorbed at 4 °C for 14 h. The product was collected by magnetic separation, washed with buffer, and freeze-dried to obtain glucosamine thioglycoside-loaded functionalized chitosan. The mass ratio of glucosamine thioglycoside, polydopamine ferrite-functionalized chitosan carrier, and phosphate buffer was 1:7.5:750.

[0053] S3. The glucosinolate extract and oleanolic acid were dissolved in a 70% ethanol solution. The bacterial cellulose was then immersed in the solution and soaked at room temperature for 45 minutes. After being removed, it was vacuum dried at 45°C to obtain drug-loaded bacterial cellulose. The mass ratio of glucosinolate extract, oleanolic acid and ethanol solution was 1:0.4:75.

[0054] S4. Disperse glucosinolate-loaded functionalized chitosan in deionized water, immerse drug-loaded bacterial cellulose in the dispersion, shake at 4°C for 18 hours, remove and freeze-dry to obtain the wound dressing; wherein the mass ratio of glucosinolate-loaded functionalized chitosan to deionized water is 1:150.

[0055] Comparative Example 1

[0056] In this comparative example, no polydopamine ferrite was added in step S1, nor was the reaction step of Fe3O4 nanoparticles with dopamine hydrochloride carried out. Aldehyde-modified chitosan was used directly as the carrier. All other aspects were the same as in Example 3.

[0057] Comparative Example 2

[0058] In step S3 of this comparative example, only the glucosinolate extract was used, and the oleanolic acid component was omitted. All other steps were the same as in Example 3.

[0059] Results Analysis

[0060] The various embodiments and comparative examples of the present invention were characterized and tested.

[0061] Test Example 1

[0062] Figure 1 Infrared images of unmodified chitosan (a), aldehyde-modified chitosan (b), polydopamine ferrite-functionalized chitosan carrier (c), and glucosinolate-loaded glucosinolate-functionalized chitosan (d).

[0063] Depend on Figure 1 (a) and Figure 1 (b) By comparison, it can be seen that: 3432cm -1 and 3291cm -1 The decrease in absorbance at 1726 cm⁻¹ indicates a reduction in the number of OH and NH groups. -1The absorbance increases at this point, forming the C=O stretching vibration peak of the aldehyde group, at 1648 cm⁻¹. -1 The decrease in absorbance and the weakening of NH bending vibration indicate that the aldehyde reaction of chitosan was successfully carried out.

[0064] Depend on Figure 1 (b) and Figure 1 (c) By comparison, it can be seen that: 2709cm -1 The absorbance decreased significantly at 1648 cm⁻¹, indicating that the aldehyde group was consumed. -1 The absorbance increases at this point, forming a C=N double bond, 3432 cm⁻¹ -1 and 3291cm -1 The absorbance showed a slight increase, which came from the -OH and -NH of polydopamine, indicating that the Schiff base reaction in step S1 was successful and the polydopamine ferrite-functionalized chitosan carrier was synthesized.

[0065] Depend on Figure 1 (c) and Figure 1 (d) By comparison, it can be seen that: 1648cm -1 and 1572cm -1 The absorbance increased significantly at 3432 cm⁻¹, forming protein amide I and amide II bands. -1 and 3291cm -1 The absorbance further increased, originating from the NH and OH groups of the protein. This indicates that the polydopamine ferrite-functionalized chitosan carrier successfully loaded glucosinolates.

[0066] Test Example 2

[0067] Fresh, detached pigskin was collected, subcutaneous fat was removed, and the skin was washed with physiological saline. To simulate postoperative wound exudation, a layer of artificial tissue exudate (containing 0.9% NaCl and 1% bovine serum albumin) was evenly applied to the pigskin surface, keeping it moist. Each test dressing was cut into strips of 2.5cm × 10cm and applied to the prepared pigskin. A 200g weight was used to roll the dressing three times at a uniform speed to ensure close contact. The pigskin with the dressing applied was fixed to the lower clamp of a universal testing machine, and the free end of the dressing was folded 180° and clamped to the upper clamp. Vertical peeling was performed at a speed of 300mm / min, and the maximum force during peeling was recorded. Five parallel samples were tested in each group, and the results were averaged, in N / 25mm. The test results are shown below. Figure 2 .

[0068] like Figure 2As shown, the peel strength of each of Examples 3 is much higher than that of Comparative Example 1, which does not contain polydopamine ferrite. This proves that aldehyde-modified chitosan and polydopamine ferrite play a synergistic role in this invention. The catechol groups of polydopamine are tightly bound to the tissue surface through coordination bonds and hydrogen bonds, while aldehyde-modified chitosan forms a covalent cross-linked network with the amino groups of tissue proteins through Schiff base reaction. The synergy between the two achieves a strength higher than that of simple physical adsorption or single-component adhesion.

[0069] Test Example 3

[0070] The enzyme activity of each group of dressings was tested using the following steps: The glucosinolate-functionalized chitosan prepared in Examples 1-3 and the glucosinolate-functionalized chitosan prepared in Comparative Example 1 were placed in phosphate buffer (pH 6.0) and stored at 4°C. Samples were taken on days 0, 7, 15, and 30. Using glucosinolates as a substrate, the mixture was reacted at 37°C for 30 min. The amount of isothiocyanate released was determined by UV spectrophotometry, and the enzyme activity retention rate was calculated. The enzyme activity on day 0 was considered 100%, and three replicates were tested for each group. Results are shown below. Figure 3 .

[0071] Depend on Figure 3 It can be seen that Examples 1-3 maintained high enzyme activity during the 30-day storage period, with an activity retention rate of over 86% after 30 days, indicating that the polydopamine ferrite-functionalized chitosan carrier has a good immobilization and protection effect on glucosinolates. In contrast, in Comparative Example 1, the enzyme was only physically adsorbed onto the ordinary chitosan carrier, lacking covalent binding and the protection of polydopamine, resulting in rapid enzyme inactivation during storage, with an activity retention rate of only 51.4% after 30 days. The results show that the introduction of polydopamine ferrite significantly improved the storage stability of the enzyme, providing a guarantee for the long-term storage and application of the dressing.

[0072] Test Example 4

[0073] The antioxidant activity of the dressings prepared in each group was determined by a DPPH free radical scavenging experiment. The dressings prepared in Examples 1-3 and Comparative Examples 1-2 were cut into 1cm × 1cm pieces and placed in 2mL of 0.1mM DPPH ethanol solution, respectively, and reacted at room temperature in the dark for 30min. The absorbance at 517nm was measured using a UV spectrophotometer, and the free radical scavenging rate was calculated. DPPH solution without dressings was used as a blank control. Three parallel samples were tested in each group. Results are shown below. Figure 4 .

[0074] Depend on Figure 4It can be seen that Examples 1-3 all exhibited excellent free radical scavenging ability, with scavenging rates all exceeding 92%. This is mainly attributed to the abundant catechol structure on the surface of the polydopamine ferrite, which possesses highly efficient antioxidant and free radical scavenging functions. Although Comparative Example 2 lacked oleanolic acid, its polydopamine ferrite component was intact, thus maintaining a scavenging rate of 89.7%. However, Comparative Example 1, due to the complete absence of polydopamine ferrite, showed a significant decrease in free radical scavenging ability to 28.6%. The results indicate that the introduction of polydopamine ferrite endows the dressing with excellent antioxidant properties, effectively scavenging excess reactive oxygen species in the wound microenvironment, reducing oxidative stress damage to normal repair cells, and helping to improve the problem of slow healing in cancer patients.

[0075] Test Example 5

[0076] Staphylococcus aureus and Pseudomonas aeruginosa, common pathogens causing wound infections, were selected as test strains. The dressings prepared in Examples 1-3 and Comparative Examples 1-2 were cut into 1cm × 1cm pieces, sterilized with ultraviolet light, and placed in sterile test tubes containing 3mL of Mueller-Hinton liquid medium. Freshly prepared bacterial suspension was added to bring the final bacterial concentration to 1-1.5 × 10⁻⁶. 6 CFU / mL. The culture was incubated at 37℃ with shaking for 24 h, then diluted and plated to count colonies. A blank control group without dressing was used as a negative control; three replicates were performed for each group. Results are shown below. Figure 5 .

[0077] Depend on Figure 5 It can be seen that Examples 1-3 all showed significant inhibitory effects on Staphylococcus aureus and Pseudomonas aeruginosa, with a significant reduction in colony count after 24 hours compared to the initial inoculation, demonstrating a significant bactericidal effect. The antibacterial effect stems from: the broad-spectrum antibacterial activity of isothiocyanate, a hydrolysis product of glucosinolates; the anti-inflammatory and adjuvant antibacterial effects of oleanolic acid; and the antibacterial properties of polydopamine. The antibacterial effect of Comparative Example 2 was lower than that of the Examples, indicating that oleanolic acid has a synergistic effect in the antibacterial system. The antibacterial effect of Comparative Example 1 was the weakest, which may be related to poor enzyme stability and insufficient generation of active products. The lack of antibacterial activity of polydopamine itself also contributed to the reduced effect. The results indicate that the dressing of the present invention, through the synergistic effect of multiple components, exerts a broad-spectrum antibacterial effect and can effectively prevent postoperative wound infection in tumor patients.

[0078] Test Example 6

[0079] The in vitro cytotoxicity of each dressing group against mouse fibroblast L929 cells was evaluated using the CCK-8 colorimetric assay. The dressings prepared in Examples 1-3 and Comparative Examples 1-2 were cut into 1cm × 1cm pieces, sterilized with ultraviolet light, and then added to DMEM culture medium containing 10% fetal bovine serum at a ratio of 0.1g / mL. The mixture was incubated at 37°C for 24 hours to prepare the extract. L929 cells were seeded at a density of 5 × 10³ cells / well in 96-well plates and cultured for 24 hours to allow cell adhesion. The original culture medium was discarded, and the extracts from each dressing group were added, and the cells were cultured for another 24 hours and 48 hours. After reaching the culture time, 10 μL of CCK-8 reagent was added to each well, and the cells were incubated at 37°C for 2 hours. The absorbance at 450 nm was measured using a microplate reader. Cells cultured in normal medium served as the negative control group, and cells cultured in medium containing 0.5% phenol served as the positive control group. Results are shown below. Figure 6 .

[0080] from Figure 6 As can be seen, the relative cell proliferation rates at 24h and 48h in Examples 1-3 were all above 92%, and the cytotoxicity level was Grade 1, meeting the biosafety requirements for medical dressings. This indicates that the wound dressing prepared by this invention has no significant cytotoxicity to normal fibroblasts. The RGR at 24h and 48h in Comparative Example 1 were 89.5% and 84.6%, respectively, still within the Grade 1 range, but lower than in the Examples. The RGR of the positive control group was 32.6% and 21.8% at 24h and 48h, respectively, with a toxicity level of Grade 3, indicating the effectiveness of the experimental system. The cells in the negative control group grew well, further verifying the reliability of the experimental results. In summary, the wound dressing prepared by this invention has no significant cytotoxicity to L929 fibroblasts, good biocompatibility, and can be safely applied to postoperative wound care in tumor surgery, avoiding secondary damage to normal tissues and meeting the long-term, gentle, and safe nursing needs of postoperative wounds in tumor surgery.

[0081] Test Example 7

[0082] The wound healing ability of the dressings prepared in Example 3 and Comparative Examples 1-2 was characterized using a mouse full-thickness skin defect model. The results are shown in [Figure Number]. Figure 7 .like Figure 7 As shown, on day 5, the wounds of mice in Example 3 had clearly scabbed over and begun to shrink, and by day 10, they had basically healed, with the scabs falling off and only a small residue remaining at the defect site, while the control group healed slowly.

[0083] 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.

[0084] 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 method for preparing a wound dressing for postoperative care of tumor patients, characterized in that: Includes the following steps: S1. Fe3O4 nanoparticles were reacted with dopamine hydrochloride to obtain polydopamine ferrite; chitosan was oxidized with sodium periodate to obtain aldehyde-modified chitosan; aldehyde-modified chitosan was dissolved in 0.1M acetate buffer solution at pH 5.5, polydopamine ferrite was added, the mixture was ultrasonically dispersed, heated to 40-50℃, stirred for 6-8 hours, centrifuged, washed, and freeze-dried to obtain polydopamine ferrite functionalized chitosan carrier; S2. Dissolve glucosinolate in 50mM phosphate buffer at pH 6.0, add polydopamine ferrite-functionalized chitosan carrier, and shake at 4℃ for 12-16h to adsorb; collect the product by magnetic separation, wash with buffer, and freeze-dry to obtain glucosinolate-loaded functionalized chitosan. S3. Dissolve glucosinolate extract and oleanolic acid in a 70% ethanol solution, immerse bacterial cellulose in the solution, soak at room temperature for 30-60 minutes, remove and vacuum dry at 40-50℃ to obtain drug-loaded bacterial cellulose. S4. Disperse glucosinolate-functionalized chitosan in deionized water, immerse drug-loaded bacterial cellulose in the dispersion, shake at 4°C for 12-24 hours, remove and freeze-dry to obtain the wound dressing.

2. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 1, characterized in that: The preparation process of the polydopamine ferrite is as follows: Fe3O4 nanoparticles are ultrasonically dispersed in a 10mM Tris-HCl buffer solution with pH=8.5 to form a uniform dispersion. Dopamine hydrochloride is added, and the mixture is stirred at room temperature in the dark for 12-16 hours. The product is separated by magnetic separation, and then washed alternately with deionized water and ethanol until neutral. The product is then dried under vacuum to obtain the polydopamine ferrite.

3. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 2, characterized in that: The mass ratio of Fe3O4 nanoparticles, dopamine hydrochloride, and Tris-HCl buffer is 1:0.2-0.4:100-120.

4. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 3, characterized in that: The preparation process of the aldehyde-modified chitosan is as follows: chitosan is dissolved in an aqueous acetic acid solution with a volume fraction of 1%-2%, stirred until completely dissolved, sodium periodate is added, and the mixture is stirred at 25-30℃ in the dark for 4-6 hours. Finally, ethylene glycol is added, and stirring is continued for 30 minutes. The mixture is then dialyzed with deionized water for 48 hours and freeze-dried to obtain the aldehyde-modified chitosan.

5. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 4, characterized in that: The mass ratio of chitosan, sodium periodate, ethylene glycol, and acetic acid aqueous solution is 1:0.4-0.6:0.1-0.3:80-120.

6. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 5, characterized in that: In step S1, the mass ratio of aldehyde-modified chitosan, polydopamine ferrite, and acetate buffer is 1:0.2-0.5:80-120.

7. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 6, characterized in that: In step S2, the mass ratio of glucosinolates, polydopamine ferrite-functionalized chitosan carrier, and phosphate buffer is 1:5-10:500-1000.

8. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 7, characterized in that: In step S3, the mass ratio of glucosinolate extract, oleanolic acid, and ethanol solution is 1:0.3-0.5:50-100.

9. The method for preparing the wound dressing for postoperative care of tumor patients according to claim 8, characterized in that: In step S4, the mass ratio of glucosinolate-loaded glucosinolate-functionalized chitosan to deionized water is 1:100-200.

10. A wound dressing for postoperative care of tumor patients, characterized in that: Prepared by the preparation method according to any one of claims 1-9.

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