Fe-based polyphenol functionalized hydrogel, preparation method and application thereof

Abstract

The present application relates to the field of biomedical materials, in particular to a Fe-based polyphenol functionalized hydrogel and a preparation method and application thereof.The preparation method of the Fe-based polyphenol functionalized hydrogel comprises the following steps: dissolving chlorogenic acid in water, adding gelatin to dissolve to obtain a mixed solution A; dissolving ferric salt, sodium phytate and sodium chloride in water to obtain a mixed solution B; mixing the mixed solution A and the mixed solution B, adjusting the pH to be acidic and heating to react to obtain the Fe-based polyphenol functionalized hydrogel.The DPPH free radical scavenging rate of the hydrogel is as high as 91.6%.In a wound model of diabetic rats, the hydrogel significantly promotes wound healing under the condition of Staphylococcus aureus infection, and the healing rate reaches 98.38%.The material has good interfacial adhesion and antioxidant properties, and shows a broad application prospect in the field of diabetic wound treatment and related wound repair.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials, and in particular to an Fe-based polyphenol functionalized hydrogel, its preparation method, and its applications. Background Technology

[0002] Diabetic wounds are among the most common and difficult-to-treat complications of diabetes. Their healing process is often hampered by multiple pathological factors, including tissue ischemia, persistent inflammation, bacterial infection, and excessive reactive oxygen species (ROS), leading to prolonged wound healing difficulties and a high risk of deterioration into severe infection, tissue necrosis, and even amputation. While existing treatments such as routine dressing changes and moist wound therapy, antibiotics, debridement, and biological agents like growth factors can improve some symptoms, they primarily target single pathological processes and struggle to address the complex issues of infection, inflammatory imbalance, and oxidative stress simultaneously.

[0003] Hydrogels are widely used for wound closure due to their high water content, good biocompatibility, and ability to form a moist barrier, which can reduce pain, isolate contamination, and support cell migration. However, traditional hydrogels are mostly prepared by chemical or photocrosslinking, which is a complex process and may leave toxic reactants. Moreover, their functions are usually singular, making it difficult to simultaneously possess multiple regulatory capabilities such as antibacterial, anti-inflammatory, and ROS scavenging.

[0004] The amino and carboxyl groups in gelatin molecules can form dynamic and reversible coordination networks with polyvalent metal ions, enabling the rapid construction of injectable and self-healing hydrogels without chemical modification. Natural polyphenols, such as chlorogenic acid (CA), containing catechol structures, can form stable metal-polyphenol complexes with metal ions and possess antioxidant, antibacterial, and anti-inflammatory bioactivities. Therefore, the combined construction of metal-polyphenol nanoparticle crosslinked hydrogels using gelatin, metal ions, and chlorogenic acid is not only simple and safe, avoiding the use of toxic crosslinking agents, but also introduces multiple functions into the material. By scavenging ROS and regulating the inflammatory microenvironment, it effectively promotes angiogenesis, collagen deposition, and tissue repair, providing an innovative material for diabetic chronic wounds that combines structural stability and comprehensive therapeutic efficacy. Among numerous metal ions, Fe ions have strong coordination ability and variable valence state characteristics, enabling dynamic coordination with the amino and carboxyl groups in gelatin and the phenolic hydroxyl groups in polyphenols. This helps to construct a stable three-dimensional crosslinked network and improves the structural stability and tissue adhesion of the hydrogel. Meanwhile, after proper coordination and regulation, the Fe-based active center is expected to exhibit the activity of ROS-regulated enzymes such as CAT and SOD, which is beneficial for decomposing H2O2, clearing superoxide anions, and improving the ROS imbalance of diabetic wounds.

[0005] However, the function of Fe active sites is highly dependent on their local coordination environment. Excessive exposure or lack of effective regulation of Fe sites can easily induce Fenton-like pro-oxidative reactions, leading to further ROS accumulation and exacerbating oxidative stress in diabetic wounds. Furthermore, single Fe-polyphenol or Fe-gelatin systems also suffer from problems such as easy oxidation of polyphenols, self-aggregation, competitive coordination, and network heterogeneity, making it difficult to simultaneously achieve both tissue adhesion and ROS scavenging capabilities.

[0006] Therefore, there is an urgent need to develop a functionalized hydrogel system that can stably construct a Fe-based polyphenol-gelatin synergistic network under mild conditions. This system can achieve multiple regulation of the wound microenvironment, ensuring the tissue adhesion of the hydrogel network while moderately constraining the Fe active centers and regulating the local coordination environment, thereby inhibiting pro-oxidative reactions and enhancing ROS scavenging ability. This provides a safer, more efficient, and clinically translational solution for the healing of diabetic wounds. Summary of the Invention

[0007] To address the problems of insufficient regulation of Fe active centers, inadequate network stability, and limited ROS scavenging ability in existing metal-polyphenol-gelatin hydrogel systems, this invention provides an Fe-based polyphenol functionalized hydrogel, its preparation method, and its application in the treatment of diabetic wounds.

[0008] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is a method for preparing Fe-based polyphenol functionalized hydrogels, comprising the following steps: Chlorogenic acid is dissolved in water, and gelatin is added to dissolve it to obtain mixed solution A; Dissolve ferric salt, sodium phytate, and sodium chloride in water to obtain mixed solution B; Mix solution A and mixed solution B, adjust the pH to acidic and heat to react, to obtain Fe-based polyphenol functionalized hydrogel (denoted as Fe / CA-Gel hydrogel).

[0009] The second technical solution of the present invention is a Fe-based polyphenol functionalized hydrogel prepared by the above-mentioned preparation method.

[0010] The third technical solution of this invention is the application of the above-mentioned Fe-based polyphenol functionalized hydrogel in the preparation of diabetic wound dressings.

[0011] The fourth technical solution of the present invention is a diabetic wound dressing, comprising the above-mentioned Fe-based polyphenol functionalized hydrogel.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention constructs a metal polyphenol-gelatin hydrogel system, achieving a significant improvement in the structural and biological functions of the hydrogel through multiple synergistic effects between metal polyphenol and gelatin molecules. This system not only effectively enhances the tissue adhesion of the hydrogel, reaching 11.6 kPa, thus providing a stable and effective physical barrier for the wound, but more importantly, it can efficiently scavenge free radicals, thereby effectively alleviating oxidative stress in diabetic wounds and improving the wound microenvironment.

[0013] (2) In this invention, chlorogenic acid (CA) and sodium phytate (Na-Phytate) are introduced simultaneously during the hydrogel synthesis process. These two substances synergistically regulate the local coordination environment of the Fe active site, thereby effectively regulating Fe-based enzyme-like activity. CA can form a metal-polyphenol coordination structure with Fe ions through polyphenolic hydroxyl groups, providing a certain free radical scavenging ability. Na-Phytate, on the other hand, coordinates with Fe ions through polyphosphate groups, providing appropriate constraint on the Fe active site and reducing POD reactions initiated by Fe sites. The synergistic effect of these two substances can construct a stable and balanced Fe-CA-Na-Phytate-Gel network, resulting in lower POD-like activity and stronger CAT and SOD-like activity. Based on this synergistic regulation, further optimization of the Na-Phytate dosage can enable the hydrogel to achieve even better ROS scavenging ability and antioxidant properties.

[0014] (3) The Fe / CA-Gel hydrogel prepared in this invention exhibits excellent tissue adhesion and significant antioxidant capacity. Its DPPH free radical scavenging rate is as high as 91.6%. In a diabetic rat wound model, this hydrogel significantly promoted wound healing under Staphylococcus aureus infection conditions, with a healing rate of 98.38%. Due to its good interfacial adhesion and antioxidant properties, this material shows broad application prospects in the treatment of diabetic wounds and related wound repair. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The image shows a scanning electron microscope (SEM) image of the sample from Example 1. Figure 2 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the sample from Example 1. Figure 3 These are tissue adhesion test images of samples from Examples 1-3 and Comparative Examples 1-4; Figure 4 For the peroxidase-like (POD) activity test of the samples of Example 1 and Comparative Examples 1-6; Figure 5 The catalase-like (CAT) activity of the samples from Example 1 and Comparative Examples 1-6 was tested. Figure 6 The superoxide dismutase (SOD) activity of the samples from Example 1 and Comparative Examples 1-6 was tested. Figure 7 The images show the MTT biocompatibility test results for samples from Examples 1-3 and Comparative Examples 1-4. Figure 8 The graph shows the DPPH radical scavenging efficiency of samples from Examples 1-3 and Comparative Examples 1-6. Figure 9 Images showing the wound healing of diabetic rats from Example 1; Figure 10 The results show the statistical results of wound healing rate in diabetic rats from Example 1. Detailed Implementation

[0017] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0018] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0019] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0020] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0021] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0022] The first aspect of this invention provides a method for preparing Fe-based polyphenol functionalized hydrogels, comprising the following steps: Chlorogenic acid is dissolved in water, and gelatin is added to dissolve it to obtain mixed solution A; Dissolve ferric salt, sodium phytate, and sodium chloride in water to obtain mixed solution B; Mix solution A and mixed solution B, adjust the pH to acidic and heat to react, to obtain Fe-based polyphenol functionalized hydrogel (denoted as Fe / CA-Gel hydrogel).

[0023] In a preferred embodiment of the present invention, the ratio of chlorogenic acid, gelatin and water in mixed solution A is 10 mg: (1-3) g: (15-30) mL.

[0024] In a preferred embodiment of the present invention, the ratio of ferric salt, sodium phytate, sodium chloride and water in mixed solution B is (0.16-0.25) mmol: (4-7) mmol: (2-6) mmol: (15-30) mL; the ferric salt is ferric chloride.

[0025] In a preferred embodiment of the present invention, when preparing mixed solution A, the conditions for dissolving gelatin are set as follows: 40-60°C, time 1-3 hours; when preparing mixed solution B, ferric salt, sodium phytate, and sodium chloride are dissolved in water by ultrasound; the ultrasound time is 7-15 minutes. The present invention does not impose any particular limitation on the power of the ultrasound; any ultrasound power commonly used by those skilled in the art can be used.

[0026] In a preferred embodiment of the present invention, the volume ratio of mixed solution A to mixed solution B is 1:1.

[0027] In a preferred embodiment of the present invention, adjusting the pH to acidity specifically means adjusting the pH to 4-5; the conditions for the heating reaction are set as follows: 50-80℃ for 1-4 hours.

[0028] In a preferred embodiment of the present invention, the conditions for the heating reaction are set as follows: 50-80°C for 1-4 hours; after the heating reaction is completed, a washing step is also included.

[0029] A second aspect of the present invention provides a Fe-based polyphenol functionalized hydrogel prepared by the above-described preparation method.

[0030] The third aspect of this invention provides the application of the above-mentioned Fe-based polyphenol functionalized hydrogel in the preparation of diabetic wound dressings.

[0031] A fourth aspect of the present invention provides a diabetic wound dressing comprising the above-mentioned Fe-based polyphenol functionalized hydrogel.

[0032] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0033] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1 (1) Dissolve 40 mg of CA (chlorogenic acid) in 20 mL of deionized water by sonication for 10 min to obtain an aqueous solution of CA. Then add 2 g of gelatin powder to the aqueous solution of CA and stir at 50 °C for 2 h to obtain a homogeneous and transparent mixed solution A. Dissolve 0.2 mmol of FeCl3 (ferric chloride), 5 mmol of Na-Phytate (sodium phytate) and 4 mmol of NaCl (sodium chloride) in 20 mL of deionized water by sonication for 10 min to obtain a mixed solution B.

[0035] (2) Add mixed solution A to mixed solution B and stir magnetically for 10 min to make the solution homogeneous. Adjust the pH of the mixed solution to 4.5 with CPBS (citric acid-sodium citrate) buffer (pH 3.5) and react in a water bath at 60°C for 3 h to form a gel. Then wash the reaction product three times with deionized water to obtain Fe / CA-Gel hydrogel, which is recorded as the sample of Example 1.

[0036] SEM tests were performed on the sample from Example 1 (test results are shown in [link]). Figure 1 ) and XPS test (test results can be found in...) Figure 2 The sample from Example 1 was processed before testing.

[0037] The sample processing method for Example 1 is as follows (the same applies below): The sample of Example 1 is placed in a freeze dryer and freeze-dried at -80°C for 24 hours to obtain the solid to be tested.

[0038] Figure 1 The SEM EDS-mapping image of the sample from Example 1 is shown. It can be seen that the sample exhibits a loose, porous network structure, indicating the successful synthesis of the hydrogel. This is attributed to Fe... 3+ Coordination with Na-Phytate and Gel side chain functional groups leads to the formation of cross-linked hydrogels, which is the main force driving hydrogel formation. Furthermore, Fe... 3+Coordination with CA forms a metal-phenolic network (MPN), and CA, as an excellent hydrogen bond donor, forms hydrogen bonds with gel. These forces work synergistically to form the hydrogel of the sample in Example 1. Figure 2 The XPS data for Fe 2p in the sample of Example 1 are shown. 2+ / Fe 3+ The proportions are more stable and balanced, accounting for 48% and 52% respectively.

[0039] Tissue adhesion tests were performed on the sample from Example 1, and the results are shown below. Figure 3 .

[0040] Depend on Figure 3 As can be seen, the tissue adhesion strength of the sample in Example 1 was the best, reaching 11.6 kPa, far exceeding that of the other comparative examples. This may be because the catechol (catechol) groups in the CA molecule can interact with polar sites of tissue surface proteins through hydrogen bonds and π-π bonds, thereby enhancing tissue adhesion. Furthermore, Na-Phytate is rich in phosphate groups, which can coordinate with Fe ions and form electrostatic and hydrogen bonding interactions with amino groups on the Gel molecular chain, thus increasing the crosslinking density, stability, and cohesive strength of the hydrogel network. On the other hand, Na-Phytate phosphate groups can form non-covalent interactions such as ionic interactions and hydrogen bonds with polar groups in tissue surface proteins, thus further enhancing tissue adhesion. Gel provides good biocompatibility and tissue surface contact ability, enabling it to better adhere to and wet the microstructure of the tissue surface, effectively increasing the contact area and further improving adhesion. These combined effects endow the prepared hydrogel with excellent tissue adhesion properties.

[0041] The POD activity of the sample from Example 1 was tested (the test results are shown in [link to sample 1]). Figure 4 CAT activity test (test results are available in [link to test results]). Figure 5 ) and SOD activity test (test results are shown in Figure 6 The test method is as follows. Before testing, the sample from Example 1 was treated using the same method as above: POD activity test method: A suspension (1 mg / mL), TMB (3,3',5,5'-tetramethylbenzidine) (1 mM), and H2O2 (100 mM) solution of the sample from Example 1 were prepared using pure water. Subsequently, 50 µL of the Example 1 suspension, 150 µL of H2O2, and 150 µL of TMB were mixed in 2650 µL of sodium acetate-acetic acid (NaAc-HAc, pH=4, 0.2 M) buffer solution and incubated at room temperature for 30 min. The absorbance of the reaction solution was measured at 652 nm using a UV-Vis spectrophotometer to evaluate the POD activity of the Example 1 sample.

[0042] CAT activity test method: Add 500 µg of the sample from Example 1 to 5 mL of 50 mM H2O2 solution to make the final concentration of the solution 100 µg / mL. -1 After stabilizing for 5 minutes, the dissolved oxygen concentration was recorded every 30 seconds for 20 minutes.

[0043] SOD activity test method: The samples from Example 1 were prepared in doses of 25, 50, 75, and 100 µg / mL. -1 The dispersion was prepared by adding 20 µL of the dispersion to a 96-well plate, followed by 160 µL of WST-8 / enzyme working solution (containing SOD detection buffer, WST-8, and xanthine oxidase) and 20 µL of xanthine reaction initiation solution. Blank1 and Blank2 were set up as controls. After incubating the reaction system at 37 °C in the dark for 30 min, the absorbance was measured at 450 nm. The SOD inhibition rate was calculated using the inhibition rate formula, and a concentration-inhibition rate curve was plotted to characterize the SOD activity of the material.

[0044] Depend on Figure 4 It can be seen that the POD activity of the sample in Example 1 is very weak, significantly lower than that of Comparative Examples 3-5. Figure 5 and Figure 6 It can be seen that the sample of Example 1 has superior SOD and CAT enzyme activities compared to Comparative Examples 3-5, indicating that it has a relatively stronger ROS scavenging ability. This may be because the appropriate amount of sodium phytate in the sample of Example 1 can form an effective but not excessive coordination constraint on the Fe active site, forming a more balanced Fe-Na-Phytate-CA synergistic coordination environment, which inhibits the overactive Fe sites required by POD, causing them to convert to the competitive reaction CAT, while retaining SOD activity.

[0045] The MTT assay was used to test the biocompatibility of the sample from Example 1 (the test results are shown in [link to results]). Figure 7 The test method is as follows: the sample of Example 1 is treated before the test, and the treatment method is the same as above.

[0046] Test method: L929 cells were prepared at a concentration of 1×10⁻⁶. 4 Cells were seeded at a density of [number] cells / well in 96-well plates. After incubation for 1 day, the original culture medium was replaced with 100 μL of fresh culture medium containing different concentrations (1 / 5 / 10 / 20 / 30 μg / mL) of the treated Sample 1 from Example 1. Deionized water served as the negative control, and normal culture medium served as the positive control. Incubation continued for 24 h. Subsequently, the culture medium in the plates was removed, and 50 μL of 5 mg / mL MTT solution was added to each well. After incubation in the dark for 6 h, the MTT solution was removed, and 200 μL of dimethyl sulfoxide was added to each well for color development. The absorbance was read using a microplate reader, and the cytotoxicity of the hydrogel was calculated according to the following formula: Cell viability (%) = (O text -O neg ) / (O pos -O neg )×100%, O text O neg and O pos The absorbance at 570 nm represents the absorbance of the experimental group, negative control group, and positive control group, respectively.

[0047] from Figure 7 As can be seen, after incubation with L929 at different concentrations for 24 hours, the cell viability of the sample in Example 1 remained above 90%, which was higher than that of other comparative samples. This is because gel is derived from collagen and has good biocompatibility, while CA is a natural polyphenol that helps reduce the irritation of the material to cells and tissues. Furthermore, the hydrogel itself has high water content and softness, which better matches the microenvironment of biological tissues. These factors contribute to the good biocompatibility of the sample in Example 1.

[0048] The DPPH radical scavenging efficiency of the sample from Example 1 was tested (the test results are shown in [link to test results]). Figure 8 The test method is as follows: the sample of Example 1 is treated before the test, and the treatment method is the same as above.

[0049] DPPH free radical scavenging test: DPPH was prepared into a solution with a concentration of 0.05 mg / mL. The treated Sample 1 was prepared into dispersions of different concentrations (10-50 μg / mL), which were then mixed with the DPPH solution at a volume ratio of 1:1 and reacted at 37°C for 30 min in the dark. The absorbance was then measured at 516 nm using a UV spectrophotometer. The DPPH free radical scavenging rate was calculated based on the difference in absorbance before and after the reaction, using the following formula: DPPH scavenging(%)=((A C -A S ) / A C )×100; A C The absorbance of the control group (containing only DPPH solution) is A. S The absorbance of the sample group (including DPPH solution and sample dispersion from Example 1) is given.

[0050] Depend on Figure 8As can be seen, in the DPPH radical scavenging efficiency test, the DPPH scavenging rate of the samples from Example 1 at different concentrations were all above 70%, with the highest DPPH scavenging rate at 40 μg / mL, reaching 91.6%. This demonstrates that its radical scavenging rate is significantly higher than that of the other comparative samples. This is because Example 1 can form an optimal Fe-Na-Phytate-CA-Gel synergistic network. This moderate coordination constraint can both inhibit the excessive exposure of Fe sites, reduce POD-promoted oxidation, and suppress excessive free radical generation, while retaining the electron transfer ability of Fe sites, thus facilitating the decomposition of H2O2 and the formation of ·O2. - The removal of free radicals. This allows Example 1 to not only effectively reduce oxidative stress but also maximize free radical scavenging capacity, ultimately achieving the highest DPPH scavenging rate.

[0051] The wound healing test results for rats in Example 1 are shown in the figure below. Figure 9 and Figure 10 .

[0052] Establishment of a diabetic rat model and back wound: All animal experiments complied with the "Guidelines for Animal Care". Male ICR rats aged 6-8 weeks and weighing 200-220g were selected as experimental animals. The diabetic wound preparation was as follows: Rats were fed a high-fat diet for 2 weeks, and then intraperitoneally injected with streptozotocin (300mg / kg) dissolved in citrate buffer (pH 4.5), once daily for 7 consecutive weeks. One week later, blood glucose levels were measured via tail vein injection. Rats with blood glucose levels above 16.5 mmol / L for two consecutive weeks were identified as type 1 diabetic rats. Next, a 2cm diameter circular surgical wound was made on the back of the ether-anesthetized rats using medical scissors. Then, 1000μL of Staphylococcus aureus (1×10⁸ CFU / mL) was evenly applied to the wound, and the wound was bandaged with gauze and medical tape. 24 hours after infection, the rats were randomly divided into two groups (n=5 per group): a blank control group and the Example 1 group. The blank control group was treated with sterile PBS buffer. In Example 1, the hydrogel concentration was 100 μg / mL. 200 μL of hydrogel was injected into the rat wound using a syringe and spread. The hydrogel was replaced every 24 hours. Wound condition was measured on days 0, 3, 7, and 15. The healing rate (%) was calculated as follows: (A0 - A...) t The wound healing rate is calculated as (A0 × 100) / (A0 × 100), where A0 is the initial wound area, A0 is the initial wound area, and A0 is the initial wound area. t This represents the residual wound area at each time point.

[0053] like Figure 9 and Figure 10As shown, the blank control group had persistent pus, while the wound area in the Example 1 group was significantly reduced under the hydrogel treatment, and the wound healing rate for Staphylococcus aureus infection was 98.38%. These results indicate that the Sample 1 can significantly promote the healing of diabetic wounds.

[0054] Example 2 (1) Dissolve 40 mg CA in 15 mL of deionized water by sonication for 10 min to obtain an aqueous solution of CA. Then add 1 g of Gel powder to the aqueous solution of CA and stir at 40 °C for 3 h to obtain a homogeneous and transparent mixed solution A. Dissolve 0.16 mmol FeCl3, 4 mmol Na-Phytate and 2 mmol NaCl in 15 mL of deionized water by sonication for 7 min to obtain a mixed solution B.

[0055] (2) Add mixed solution A to mixed solution B and stir magnetically for 10 min to make the solution homogeneous. Adjust the pH of the mixed solution to 4 with CPBS buffer and react in a water bath at 50°C for 4 h to form a gel. Then wash the reaction product three times with deionized water to obtain Fe / CA-Gel hydrogel, which is recorded as the sample of Example 2.

[0056] Tissue adhesion tests were performed on the samples from Example 2, and the results are shown below. Figure 3 .

[0057] Depend on Figure 3 It can be seen that the tissue adhesion strength of the sample in Example 2 reached 10.7 kPa, which is slightly lower than that in Example 1, but much stronger than the other comparative examples.

[0058] The MTT assay was used to test the biocompatibility of the samples from Example 2 (the test results are shown in [link to results]). Figure 7 The testing method is the same as in Example 1, and the processing method for the sample in Example 2 before testing is the same as that for the sample in Example 1.

[0059] from Figure 7 It can be seen that after incubation with L929 at different concentrations for 24 hours, the cell viability of the sample in Example 2 remained above 90%, which was higher than that of the other comparative samples. This indicates that the sample in Example 3 has good biocompatibility.

[0060] The DPPH radical scavenging efficiency of the sample from Example 2 was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1, and the processing method for the sample of Example 2 before testing is the same as that for the sample of Example 1.

[0061] Depend on Figure 8It can be seen that when the DPPH free radical scavenging efficiency was tested, the DPPH scavenging rate of the samples of Example 2 at different concentrations was all above 70%. The sample of Example 2 had the highest DPPH scavenging rate at a concentration of 40 μg / mL, reaching 88.9%. Therefore, its free radical scavenging rate was slightly lower than that of Example 1, but much higher than that of the other comparative examples.

[0062] Example 3 (1) Dissolve 40 mg CA in 30 mL of deionized water by sonication for 10 min to obtain an aqueous CA solution. Then add 3 g of Gel powder to the CA aqueous solution and stir at 60 °C for 1 h to obtain a homogeneous and transparent mixed solution A. Dissolve 0.25 mmol FeCl3, 7 mmol Na-Phytate and 6 mmol NaCl in 30 mL of deionized water by sonication for 15 min to obtain a mixed solution B.

[0063] (2) Add mixed solution A to mixed solution B and stir magnetically for 10 min to make the solution homogeneous. Adjust the pH of the mixed solution to 5 with CPBS buffer and react in a water bath at 80°C for 1 h to form a gel. Then wash the reaction product three times with deionized water to obtain Fe / CA-Gel hydrogel, which is recorded as the sample of Example 3.

[0064] Tissue adhesion tests were performed on the samples from Example 3, and the results are shown below. Figure 3 .

[0065] Depend on Figure 3 It can be seen that the tissue adhesion strength of the sample in Example 3 reached 10.5 kPa, which is slightly lower than that in Examples 1-2, but much stronger than that in other comparative examples.

[0066] The MTT assay was used to test the biocompatibility of the sample from Example 3 (the test results are shown in [link to results]). Figure 7 The testing method is the same as in Example 1, and the processing method for the sample in Example 3 before testing is the same as that for the sample in Example 1.

[0067] from Figure 7 It can be seen that after incubation with L929 at different concentrations for 24 hours, the cell viability of the sample in Example 3 remained above 90%, which was higher than that of the other comparative samples. This indicates that the sample in Example 3 has good biocompatibility.

[0068] The DPPH radical scavenging efficiency of the sample in Example 3 was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1, and the processing method for the sample of Example 3 before testing is the same as that for the sample of Example 1.

[0069] Depend on Figure 8It can be seen that when the DPPH free radical scavenging efficiency was tested, the DPPH scavenging rate of the samples of Example 3 at different concentrations was all above 70%. The sample of Example 3 had the highest DPPH scavenging rate at a concentration of 40 μg / mL, reaching 82.7%. Therefore, its free radical scavenging rate was slightly lower than that of Examples 1-2, but far exceeded that of the other comparative examples.

[0070] Comparative Example 1 The only difference from Example 1 is that the addition of FeCl3 in step (1) is omitted; the remaining steps and parameters are the same as in Example 1. The resulting product is referred to as Comparative Example 1 sample.

[0071] Tissue adhesion tests were performed on the sample from Comparative Example 1. The test results are shown in [Figure Number]. Figure 3 .

[0072] Depend on Figure 3 It can be seen that the adhesion strength of Comparative Example 1 sample is 5.7 kPa, which is lower than that of Sample 1 of Example 1. This is attributed to the fact that Fe ions can form metal-polyphenol coordination with CA on the one hand, and coordination complexes with the phosphate groups of Na-Phytate on the other hand, thereby further improving the crosslinking density, cohesive strength and structural stability of the system based on the Na-Phytate-Gel electrostatic interaction. Therefore, in Comparative Example 1, which lacks Fe ions, the adhesion of the hydrogel structure decreases due to the lack of dual synergistic crosslinking of Fe-CA and Fe-Na-Phytate.

[0073] The biocompatibility of Comparative Example 1 sample was tested using the MTT assay (test results are shown in [link to results]). Figure 7 The testing method is the same as in Example 1, and the treatment method for the sample of Comparative Example 1 before testing is the same as that for the sample of Example 1.

[0074] from Figure 7 It can be seen that after incubating Comparative Example 1 sample with L929 at different concentrations for 24 hours, the cell viability remained above 80%, which is almost consistent with that of Examples 1-3. This indicates that Comparative Example 1 sample also has good biocompatibility.

[0075] The DPPH radical scavenging efficiency of Comparative Example 1 sample was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1, and the treatment method for the sample of Comparative Example 1 before testing is the same as that for the sample of Example 1.

[0076] Depend on Figure 8It can be seen that, during the DPPH radical scavenging efficiency test, the DPPH scavenging rate of the Comparative Example 1 samples with different concentrations ranged from 48% to 59%, showing a significant decrease compared to the Sample of Example 1. This may be because Fe, as a coordination center, forms a coordination structure with CA and Na-Phytate, regulating the electron distribution of the system and helping to enhance the radical scavenging-related reactions.

[0077] Comparative Example 2 The only difference from Example 1 is that the addition of CA in step (1) is omitted; the remaining steps and parameters are the same as in Example 1. The resulting product is referred to as Comparative Example 2 sample.

[0078] XPS analysis was performed on the comparative example 2 sample, and the test results are shown in Table 1. The processing method of the comparative example 2 sample before the test was the same as that of the sample in Example 1.

[0079] As shown in Table 1, the Fe content in the sample of Comparative Example 2 is... 2+ and Fe 3+ The percentages were 56% and 44%, respectively. 2+ The proportion is increased compared to Example 1. This is due to the lack of CA regulation of the electronic environment of Fe species.

[0080] Tissue adhesion tests were performed on the sample of Comparative Example 2, and the test results are shown below. Figure 3 .

[0081] Depend on Figure 3 As can be seen, the adhesion strength of the Comparative Example 2 sample is 4.6 kPa, which is much lower than that of the Example 1 sample. This is because the catechol groups in CA are important adhesive functional units in the system. The lack of CA reduces the effective adhesion sites in the system, resulting in a decrease in overall adhesion performance.

[0082] POD activity was tested on the comparative example 2 sample (test results are shown in...). Figure 4 CAT activity test (test results are available in [link to test results]). Figure 5 ) and SOD activity test (test results are shown in Figure 6 The testing method is the same as in Example 1. The treatment method for the sample of Comparative Example 2 before testing is the same as that for the sample of Example 1.

[0083] Depend on Figure 4 It can be seen that the POD activity of the sample in Comparative Example 2 is significantly increased compared to that in Example 1. Figure 5 and Figure 6 It can be seen that the CAT and SOD activities of the Comparative Example 2 sample were significantly lower than those of Example 1. This is because the polyphenolic hydroxyl groups in the CA molecule can react with Fe. 3+CA forms a metal-polyphenol coordination structure and participates in regulating the electronic environment around the Fe site. CA itself also possesses certain antioxidant capabilities. Without CA, the system lacks Fe-CA coordination and polyphenol antioxidant units, relying solely on Na-Phytate to regulate the Fe site, making it difficult to form a stable Fe-CA-Na-Phytate synergistic coordination environment. Therefore, the Fe active center is more likely to favor the H2O2-promoted oxidation pathway, resulting in a significant increase in POD activity and a decrease in ROS scavenging ability.

[0084] The biocompatibility of the comparative example 2 sample obtained in step (2) was tested using the MTT assay (the test results are shown in [see table]). Figure 7 The testing method is the same as in Example 1, and the treatment method for the sample of Comparative Example 1 before testing is the same as that for the sample of Example 1.

[0085] from Figure 7 It can be seen that the cell viability of Comparative Example 2 samples remained above 80% after incubation with L929 at different concentrations for 24 hours. This indicates that Comparative Example 2 samples also have good biocompatibility and no obvious cytotoxicity.

[0086] The DPPH radical scavenging efficiency of Comparative Example 2 sample was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1, and the treatment method for the sample of Comparative Example 1 before testing is the same as that for the sample of Example 1.

[0087] Depend on Figure 8 It can be seen that, during the DPPH radical scavenging efficiency test, the DPPH scavenging rate of the Comparative Example 2 samples at different concentrations ranged from 35% to 40%, showing a significant decrease compared to the Sample of Example 1. This is because the CA molecule contains an ortho-dihydroxy polyphenol structure, which can effectively scavenge DPPH radicals through hydrogen donation or electron donation, and is one of the main anti-radical active components in the system. Without the addition of CA, the number of active sites in the system that can directly participate in DPPH radical quenching is reduced, thus decreasing its radical scavenging ability.

[0088] Comparative Example 3 The only difference from Example 1 is that the addition of Na-Phytate in step (1) is omitted; the remaining steps and parameters are the same as in Example 1. The resulting product is designated as Comparative Example 3 sample.

[0089] XPS analysis was performed on the comparative example 3 sample, and the test results are shown in Table 1. The processing method of the comparative example 3 sample before the test was the same as that of the sample in Example 1.

[0090] As shown in Table 1, the Fe content in the sample of Comparative Example 3 is... 2+ and Fe 3+ The percentages were 63% and 37%, respectively.2+ The proportion increased compared to Example 1. This is due to the lack of Na-Phytate regulation of the Fe species coordination environment.

[0091] Tissue adhesion tests were performed on Comparative Example 3 samples, and the results are shown below. Figure 3 .

[0092] Depend on Figure 3 As can be seen, the adhesion strength of Comparative Example 3 sample is 3.2 kPa, which is much lower than that of Example 1 sample. This is because the metal-polyphenol-gelatin crosslinking nodes formed by Na-Phytate phosphate groups are missing, and the auxiliary interfacial interaction with polar groups on the tissue surface is reduced, thereby reducing the cohesive force and interfacial bonding ability of the hydrogel.

[0093] POD activity was tested on the comparative example 3 sample (test results are shown in...). Figure 4 CAT activity test (test results are available in [link to test results]). Figure 5 ) and SOD activity test (test results are shown in Figure 6 The testing method is the same as in Example 1, and the treatment method for the comparative example 3 sample before testing is the same as that for the sample in Example 1.

[0094] Depend on Figure 4 It can be seen that the POD activity of Comparative Example 3 is enhanced, but weaker than that of Comparative Example 2. From Figure 5 and Figure 6 It can be seen that the CAT and SOD activities of Comparative Example 3 were both weakened. This is because the lack of further coordination constraint of the Fe site by the Na-Phytate polyphosphate group resulted in a relatively higher exposure of the Fe active center, making it more likely to participate in H2O2-related pro-oxidation reactions, thus exhibiting the highest POD activity. Meanwhile, although CA itself has a certain ROS scavenging ability, its phenolic hydroxyl groups can directly participate in free radical scavenging and can undergo some coordination with Fe. However, in the absence of Na-Phytate, this effect mainly plays a basic antioxidant and partial stabilizing role, which is insufficient to fully inhibit the reaction tendency of Fe sites towards POD. Therefore, the system as a whole still exhibits strong pro-oxidation characteristics. Precisely because the Fe site lacks further regulation, H2O2 is less likely to effectively shift to the CAT reaction pathway. Although Comparative Example 3 without Na-Phytate retained the basic ROS scavenging effect brought by CA, the lack of Na-Phytate regulation of the local coordination environment of Fe prevented the establishment of a synergistic microenvironment that inhibits POD and enhances CAT and SOD.

[0095] The biocompatibility of Comparative Example 3 sample was tested using the MTT assay (test results are shown in [link to results]). Figure 7 The testing method is the same as in Example 1, and the treatment method for the comparative example 3 sample before testing is the same as that for the sample in Example 1.

[0096] from Figure 7 It can be seen that the cell viability of Comparative Example 3 samples remained above 80% after incubation with L929 at different concentrations for 24 hours. This indicates that Comparative Example 2 samples also have good biocompatibility and no obvious cytotoxicity.

[0097] The DPPH radical scavenging efficiency of Comparative Example 3 was tested (the test results are shown in the figure). Figure 8 The testing method is the same as in Example 1, and the treatment method for the comparative example 3 sample before testing is the same as that for the sample in Example 1.

[0098] Depend on Figure 8 It can be seen that during the DPPH radical scavenging efficiency test, the DPPH scavenging rate of the Comparative Example 3 samples with different concentrations ranged from 46% to 55%, showing a significant decrease compared to the Sample of Example 1. This may be because the lack of coordination regulation by Na-Phytate resulted in complete exposure of the Fe sites, leading to the strongest POD activity and the highest amount of free radical generation in the system. Although CA itself has a certain free radical scavenging ability, the lack of Na-Phytate regulation resulted in the Fe sites being in an extremely active state, and the excessive generation of free radicals made the DPPH scavenging ability the worst.

[0099] Comparative Example 4 The only difference from Example 1 is that the addition of Na-Phytate and CA in step (1) is omitted; the remaining steps and parameters are the same as in Example 1. The resulting product is designated as Comparative Example 4 sample.

[0100] XPS analysis was performed on Comparative Example 4 sample, and the test results are shown in Table 1. The processing method of Comparative Example 4 sample before testing was the same as that of Sample 1 in Example 1.

[0101] As shown in Table 1, the Fe content in the sample of Comparative Example 4 is... 2+ and Fe 3+ The percentages were 75% and 35%, respectively. 2+ The proportion was significantly increased compared to Example 1. This is due to the lack of synergistic regulation of the electronic environment of Fe species by Na-Phytate and CA.

[0102] Tissue adhesion tests were performed on Comparative Example 4 sample, and the results are shown below. Figure 3 .

[0103] Depend on Figure 3 It can be seen that the adhesion strength of Comparative Example 4 sample is 1.3 kPa, which is much lower than that of Example 1 sample and also lower than that of Comparative Examples 1-3. This is because Comparative Example 4 sample relies solely on Fe. 3+Coordination with functional groups in the gel molecular chain forms a gel network, with a relatively simple cross-linking mechanism. Without CA, the number of catechol / polyphenol adhesion sites in the system decreases, making it difficult to form effective non-covalent interactions with tissue surface proteins. Without Na-Phytate, the system loses phosphate-assisted interfacial binding and Fe... 3+ The enhanced coordination and cross-linking properties lead to a decrease in both the cohesive force of the hydrogel network and its interfacial adhesion. Therefore, Comparative Example 4 exhibits the lowest tissue adhesion strength, further demonstrating the synergistic effect of CA and Na-Phytate in improving the tissue adhesion of the hydrogel.

[0104] POD activity was tested on Comparative Example 4 (test results are shown in...). Figure 4 CAT activity test (test results are available in [link to test results]). Figure 5 ) and SOD activity test (test results are shown in Figure 6 The testing method is the same as in Example 1. The treatment method for the sample of Comparative Example 4 before testing is the same as that for the sample of Example 1.

[0105] Depend on Figure 4 It can be seen that the POD activity of Comparative Example 4 was the highest, higher than that of Comparative Examples 2, 3, and 5. From Figure 5 and Figure 6 It can be seen that the CAT and SOD activities of Comparative Example 4 sample were the lowest. These results indicate that when both CA and Na-Phytate are lacking in the system, the Fe active center lacks effective coordination regulation, making it more likely to participate in H2O2-related pro-oxidation reactions, resulting in a significant bias towards POD-like activity and hindering conversion to the CAT and SOD reaction pathways. This may be because CA can react with Fe... 3+ The formation of metal-polyphenol coordination provides a certain antioxidant effect, while Na-Phytate can further constrain Fe sites through polyphosphate groups. The two work synergistically to regulate the local coordination environment of Fe, thereby inhibiting POD-like pro-oxidation reactions and enhancing CAT / SOD activities. Comparative Example 4 lacks both CA and Na-Phytate, and therefore cannot form the above-mentioned synergistic regulatory effect, thus exhibiting the highest POD activity and the lowest CAT and SOD activities.

[0106] The biocompatibility of Comparative Example 4 sample was tested using the MTT assay (test results are shown in [link to results]). Figure 7 The testing method is the same as in Example 1. The treatment method for the sample of Comparative Example 4 before testing is the same as that for the sample of Example 1.

[0107] from Figure 7 It can be seen that the cell viability of Comparative Example 4 sample remained above 80% after incubation with L929 at different concentrations for 24 hours. This indicates that Comparative Example 4 sample also has good biocompatibility and no obvious cytotoxicity.

[0108] The DPPH radical scavenging efficiency of Comparative Example 4 was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1. The treatment method for the sample of Comparative Example 4 before testing is the same as that for the sample of Example 1.

[0109] Depend on Figure 8 It can be seen that, during the DPPH radical scavenging efficiency test, the DPPH scavenging rate of Comparative Example 4 samples at different concentrations ranged from 12% to 17%, significantly lower than that of Sample 1. This may be because Comparative Example 4 samples did not contain CA, resulting in a lack of active sites for radical scavenging, such as polyphenolic hydroxyl groups, that can directly donate hydrogen or electrons. Furthermore, the absence of Na-Phytate meant that Fe sites lacked effective coordination regulation, making it difficult to form a synergistic microenvironment conducive to ROS scavenging. This system primarily relies on Fe... 3+ It forms a basic coordination network with gel, exhibits weak antioxidant activity, and therefore shows a low DPPH free radical scavenging rate.

[0110] Comparative Example 5 The only difference from Example 1 is that the amount of Na-Phytate added in step (1) is changed to 1 mmol. All other steps and parameters are the same as in Example 1. The resulting product is designated as Comparative Example 5.

[0111] POD activity was tested on Comparative Example 5 (test results are shown in...). Figure 4 CAT activity test (test results are available in [link to test results]). Figure 5 ) and SOD activity test (test results are shown in Figure 6 The testing method is the same as in Example 1. The treatment method for the comparative example 5 samples before testing is the same as that for the samples in Example 1.

[0112] Depend on Figure 4 It can be seen that the POD activity of Comparative Example 5 is significantly stronger than that of Example 1, but lower than that of Comparative Example 3. Figure 5 and Figure 6It can be seen that the CAT activity of Comparative Example 5 was significantly weaker than that of Example 1, but stronger than that of Comparative Example 3, while the SOD activity was also weaker than that of Example 1, but stronger than that of Comparative Example 3. This may be because only a low concentration of Na-Phytate (1 mmol) was introduced during the synthesis process, and its polyphosphate groups were able to coordinate with some Fe sites, thereby constraining the Fe active centers and reducing the tendency of some overexposed Fe sites to participate in H2O2-promoted oxidative cracking. Therefore, its POD activity decreased compared to Comparative Example 3. At the same time, chlorogenic acid itself has a certain ROS scavenging ability, and its phenolic hydroxyl groups can participate in free radical scavenging and can form coordination synergy with Fe. Therefore, in the presence of low concentration of Na-Phytate, the system retains the direct antioxidant contribution of chlorogenic acid on the one hand, and on the other hand, Na-Phytate may regulate the local coordination environment around Fe, so that the reaction system shifts from a pro-oxidative pathway to a pathway more conducive to ROS scavenging. Therefore, the CAT and SOD activities are improved compared to Comparative Example 3. However, due to the low sodium phytate content, this regulation is still insufficient and not enough to form a stable, uniform and moderately constrained Fe-Na-Phytate-CA synergistic microenvironment. Therefore, its inhibition of POD and enhancement of CAT and SOD are limited.

[0113] The biocompatibility of Comparative Example 5 obtained in step (2) was tested using the MTT assay (the test results are shown in [see table]). Figure 7 The testing method is the same as in Example 1. The treatment method for the comparative example 5 samples before testing is the same as that for the samples in Example 1.

[0114] from Figure 7 It can be seen that the cell viability of Comparative Example 5 samples remained above 90% after incubation with L929 at different concentrations for 24 hours. This indicates that Comparative Example 5 samples have good biocompatibility.

[0115] The DPPH radical scavenging efficiency of Comparative Example 5 was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1. The treatment method for the comparative example 5 samples before testing is the same as that for the samples in Example 1.

[0116] Depend on Figure 8 As can be seen, in the DPPH radical scavenging efficiency test, the DPPH scavenging rate of the Comparative Example 5 samples with different concentrations ranged from 55% to 68%, which was significantly lower than that of the Sample 1. This may be because the Na-Phytate concentration was low (1 mmol), which made the regulatory effect on Fe sites less obvious than that in Example 1. Although the low concentration of Na-Phytate could inhibit POD activity to some extent and improve CAT activity to a certain extent, some free radicals were still generated due to insufficient regulatory strength.

[0117] Comparative Example 6 The only difference from Example 1 is that the amount of Na-Phytate added in step (1) is changed to 15 mmol. All other steps and parameters are the same as in Example 1. The resulting product is designated as Comparative Example 6.

[0118] POD activity was tested on Comparative Example 6 (test results are shown in...). Figure 4 CAT activity test (test results are available in [link to test results]). Figure 5 ) and SOD activity test (test results are shown in Figure 6 The testing method is the same as in Example 1. The treatment method for the comparative example 6 samples before testing is the same as that for the samples in Example 1.

[0119] Depend on Figure 4 It can be seen that the POD activity of Comparative Example 6 is stronger than that of Example 1, but lower than that of Comparative Examples 3 and 5. Figure 5 and Figure 6 It can be seen that the CAT activity of Comparative Example 6 is weaker than that of Example 1, but stronger than that of Comparative Examples 3 and 5, while the SOD activity is weaker than that of Example 1, but stronger than that of Comparative Example 3. This may be because only a high concentration of Na-Phytate (15 mmol) was introduced during the synthesis process, which significantly enhanced the coordination and chelation of polyphosphate groups to Fe sites in the system. Therefore, it can more effectively weaken the tendency of Fe to participate in H2O2-promoted oxidative cracking, so its POD activity is further reduced compared to Comparative Example 5, making the reaction pathway of the reaction system biased towards CAT conversion. On the other hand, chlorogenic acid itself has a certain ROS scavenging ability. Its phenolic hydroxyl groups can directly participate in free radical scavenging and form a coordination synergy with Fe. In the presence of high concentration of Na-Phytate, this antioxidant basis is still retained, so the sample as a whole still shows good ROS scavenging activity. However, due to the excessively high concentration of Na-Phytate, it may weaken the original synergistic coordination balance between Fe and CA to a certain extent, which is not conducive to the effective electron transfer and substrate contact required for the SOD reaction. Therefore, although its SOD activity is still higher than that of Comparative Example 3, it is still lower than that of Example 1. This indicates that while excessive Na-Phytate is more beneficial in suppressing the pro-oxidation tendency of Fe, it may cause the system to deviate from the optimal cooperative state due to excessive coordination.

[0120] The biocompatibility of Comparative Example 6 samples was tested using the MTT assay (test results are shown in [link to results]). Figure 7 The testing method is the same as in Example 1. The treatment method for the comparative example 6 samples before testing is the same as that for the samples in Example 1.

[0121] from Figure 7 It can be seen that the cell viability of Comparative Example 6 remained above 90% after incubation with L929 at different concentrations for 24 hours. This indicates that Comparative Example 6 has good biocompatibility.

[0122] The DPPH radical scavenging efficiency of Comparative Example 6 was tested (the test results are shown in [link to test results]). Figure 8 The testing method is the same as in Example 1. The treatment method for the comparative example 6 samples before testing is the same as that for the samples in Example 1.

[0123] Depend on Figure 8 As can be seen, in the DPPH radical scavenging efficiency test, the DPPH scavenging rate of Comparative Example 6 samples with different concentrations ranged from 56% to 70%, which was significantly lower than that of Sample 1. This may be because the Na-Phytate concentration was too high (15 mmol), which caused excessive coordination with Fe sites, potentially affecting the activity of system reactions such as electron transfer, leading to a decrease in radical scavenging rate.

[0124] Comparative analysis of Comparative Example 1 and Example 1 shows that the introduction of ferric chloride can form a metal-polyphenol-gelatin crosslinking network with CA and Na-Phytate, enhancing gel cohesion and structural stability. It may also optimize the electronic structure of the system in free radical scavenging tests, improving the system's antioxidant performance. Comparative analysis of Comparative Examples 2 and 4 with Example 1 shows that the introduced CA itself, as a powerful natural antioxidant, can directly and effectively scavenge DPPH free radicals with its phenolic hydroxyl groups. Furthermore, it provides key catechol groups that react with tissue surfaces through various interactions, enhancing interfacial adhesion. Comparative analysis of Comparative Examples 3-6 with Example 1 shows that the introduction of Na-Phytate can construct a high-density crosslinking network, acting as a key crosslinking node in the three-dimensional metal-polyphenol-gelatin network structure, contributing stronger tissue adhesion. Simultaneously, Na-Phytate can chelate Fe ions, inhibiting the system's POD reaction tendency and improving the system's resistance to H2O2 and O2. - The scavenging ability was further demonstrated in Comparative Examples 2, 3, and 4. It can be seen that when either CA or Na-Phytate is absent alone, the system struggles to form a stable and balanced Fe-CA-Na-Phytate synergistic coordination environment, leading to a decrease in the regulatory effect of Fe-based enzyme-like activity. When both CA and Na-Phytate are absent, POD activity is highest, while CAT, SOD-like activity, and DPPH free radical scavenging ability are significantly reduced. This indicates that the enhancement of Fe-based enzyme activity and ROS scavenging ability in this invention is not solely regulated by Na-Phytate, but depends on the synergistic coordination regulation of Fe sites by CA and Na-Phytate. Based on this, the addition of an appropriate amount of Na-Phytate can further optimize the coordination state of Fe sites, enabling the hydrogel to achieve optimal tissue adhesion, antioxidant properties, and diabetic wound repair effects.

[0125] Table 1. XPS analysis results of Example 1 and Comparative Examples 2-4. The test results are expressed in terms of Fe. 2+ / Fe 3+ The formation of proportion

[0126] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing Fe-based polyphenol functionalized hydrogels, characterized in that, Includes the following steps: Chlorogenic acid is dissolved in water, and gelatin is added to dissolve it to obtain mixed solution A; Dissolve ferric salt, sodium phytate, and sodium chloride in water to obtain mixed solution B; Mix solution A and mixed solution B, adjust the pH to acidic and heat to react, to obtain Fe-based polyphenol functionalized hydrogel.

2. The preparation method according to claim 1, characterized in that, In mixed solution A, the ratio of chlorogenic acid, gelatin and water is 10 mg : (1-3) g : (15-30) mL.

3. The preparation method according to claim 1, characterized in that, In mixed solution B, the ratio of ferric salt, sodium phytate, sodium chloride and water is (0.16-0.25) mmol: (4-7) mmol: (2-6) mmol: (15-30) mL; the ferric salt is ferric chloride.

4. The preparation method according to claim 1, characterized in that, The volume ratio of mixed solution A to mixed solution B is 1:

1.

5. The preparation method according to claim 1, characterized in that, When preparing mixed solution A, the conditions for dissolving gelatin are set as follows: 40-60℃, time 1-3h; when preparing mixed solution B, ferric salt, sodium phytate and sodium chloride are dissolved in water by ultrasound; the ultrasound time is 7-15min.

6. The preparation method according to claim 1, characterized in that, The adjustment of pH to acidity specifically means adjusting pH to 4-5; the conditions for the heating reaction are set as follows: 50-80℃ for 1-4 hours.

7. The preparation method according to claim 1, characterized in that, The conditions for the heating reaction are set as follows: 50-80℃ for 1-4 hours; after the heating reaction is completed, a washing step is also included.

8. A Fe-based polyphenol functionalized hydrogel prepared by the preparation method according to any one of claims 1-7.

9. The application of the Fe-based polyphenol functionalized hydrogel as described in claim 8 in the preparation of diabetic wound dressings.

10. A diabetic wound dressing, characterized in that, Including the Fe-based polyphenol functionalized hydrogel as described in claim 8.

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