Antibacterial and immune regulation hydrogel, and preparation method and application thereof

Abstract

The application belongs to the field of biomedical new materials, and provides an antibacterial and immune regulation hydrogel as well as a preparation method and application thereof. 3+ The three kinds of hydrogels with antibacterial, antioxidant, anti-inflammatory and immune regulation functions can be obtained based on the Schiff base bond of oDex and EPL, the ionic bond and hydrogen bond of TA and EPL, and the coordination action of TA and Fe 3+ . The hydrogel has the advantages of easy operation and low price. The hydrogel has the functions of photothermal therapy (PTT) combined with EPL and TA / Fe 3+ complexes. The hydrogel has high adhesion, can effectively inhibit the release of oxidative stress (RONS) and inflammatory factors, promote the polarization of macrophages from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, and can effectively promote the healing of mouse diabetic bacterial infection wounds.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new biological medical materials, in particular to an antibacterial and immune regulation hydrogel as well as a preparation method and application thereof. BACKGROUND

[0002] Chronic diabetic wounds are common complications of diabetes. Normal wound healing usually goes through four stages: hemostasis, inflammation, proliferation and remodeling. However, due to pathological reasons such as bacterial infection, oxidative stress, pathological inflammatory response and immune cell regulation disorder, diabetic wound healing is slow (see T. Xiang, Q. Guo, L. Jia, T. Yin, W. Huang, X. Zhang, S. Zhou, Advanced healthcare materials. 2024, 13, 2301885.). Based on the above mechanism, the effective treatment of diabetic infected wounds requires the construction of a multi-target synergistic strategy: bacterial removal, oxidative stress regulation, inflammation inhibition, macrophage polarization regulation, and proliferation promotion are the key to effective treatment of diabetic infected wounds.

[0003] In recent years, hydrogels have been widely used in diabetic wound dressings due to their drug delivery capacity, hydrophilicity and high biocompatibility (see B. H. Shan, F. G. Wu, Advanced Materials. 2024, 36, 2210707.). Hydrogels have a structure similar to the extracellular matrix of tissues, which is suitable for irregular wound sites, absorbs wound tissue exudates, and effectively maintains wound moisture, thereby promoting tissue repair and regeneration. However, many hydrogel strategies often only address one aspect of multiple processes of wound healing, and it is rare to address every aspect of the healing process (see Y. Tang, H. Xu, X. Wang, S. Dong, L. Guo, S. Zhang, X. Yang, C. Liu, X. Jiang, M. Kan, Journal of Nanobiotechnology. 2023, 21, 300.). Therefore, there is an urgent need to develop multifunctional hydrogel dressings for the treatment of diabetic infected wounds. SUMMARY

[0004] The present application provides an antibacterial and immune regulation hydrogel as well as a preparation method and application thereof to solve the technical problems mentioned in the background.

[0005] An antibacterial and immune regulation hydrogel, the hydrogel comprising oxidized dextran (oDex), epsilon-polylysine (EPL), tannic acid (TA) and ferric chloride (Fe 3+), Schiff base bond based on oDex and EPL, ionic bond and hydrogen bond of TA and EPL, and coordination of TA and Fe 3+ Three kinds of hydrogels (OETF n ) with photo-thermal assisted antibacterial, antioxidant, anti-inflammatory and immune regulation functions can be obtained.

[0006] Further, the oDex is prepared by oxidizing dextran (Dex) with sodium periodate (NaIO4); the molecular weight of the dextran is 20,000-70,000 Da, more preferably 70,000 D; and the mass ratio of NaIO4 to dextran is 0.64-1.28:1, more preferably 0.96:1.

[0007] Further, the preparation steps of the oDex are as follows:

[0008] Dex with a molecular weight of 20,000, 40,000, and 70,000 Da, respectively, is dissolved in 20 mL of deionized water;

[0009] 1.28-2.56 g of NaIO4 is dissolved in 12-24 mL of deionized water, more preferably 18 mL of deionized water;

[0010] The NaIO4 solution is added dropwise to the Dex solution, and the reaction is stirred at room temperature for 1-4 h, more preferably 4 h, then 1 mL of ethylene glycol is added to terminate the reaction, and the oDex is prepared by dialysis in deionized water and lyophilization.

[0011] Another object of the present application is to provide a preparation method of an antibacterial and immune regulation hydrogel, which comprises the following steps:

[0012] S1, oDex, EPL, TA and FeCl3·6H2O are dissolved in phosphate buffer (pH 7.4), respectively;

[0013] S2, oDex, EPL and TA are stirred and mixed uniformly, and FeCl3·6H2O solution is added;

[0014] S3, 1 M NaOH is added dropwise to the solution obtained in step S2, and the hydrogel is prepared at 37℃.

[0015] Further, the oDex concentration is 1-7 w / v %, more preferably 7 w / v %; the EPL molecular weight is 2,000-5,000 Da, more preferably 5,000 Da; the EPL concentration is 1-4 w / v %, more preferably 4 w / v %; the TA concentration is 0-1 w / v %, more preferably 0 w / v % (OE), 0.5 w / v % (OETF5) and 1 w / v % (OETF 10 ); Fe 3+ concentration is 0-0.3 w / v %, more preferably 0.15 w / v %; the 1 M NaOH addition amount is 0-20 µL, more preferably 15 µL (OETF5) and 20 µL (OETF 10 ), finally obtaining three kinds of hydrogels, which are named as OE, OETF5 and OETF 10 according to the TA concentration.

[0016] Another purpose of the present application is to provide an application of the antibacterial and immune regulation hydrogel in the preparation of medical antibacterial repair materials.

[0017] The present application has the following beneficial effects:

[0018] The hydrogel in the present application is prepared by the Schiff base bond of oDex and EPL, the ionic bond and hydrogen bond of TA and EPL, and the coordination action of TA and Fe 3+ . Through the release of EPL and TA and the combination of photothermal therapy (PTT), the antibacterial effect is achieved. Secondly, the hydrogel can clear excessive RONS at the infection site by releasing TA, reduce the oxidative stress level of the infection site, and reduce the production of inflammatory factors. In addition, the hydrogel can regulate macrophage phenotype polarization, balance M1 / M2 cell level, and promote cell proliferation, effectively treating diabetic bacterial infection wound healing. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the scanning electron microscope picture of the hydrogel obtained in the embodiment of the present application.

[0020] Figure 2 is the plate coating antibacterial result picture of the hydrogel obtained in the embodiment of the present application.

[0021] Figure 3 is the cytotoxicity result picture of the hydrogel obtained in the embodiment of the present application.

[0022] Figure 4 is the antioxidant and anti-inflammatory result picture of the hydrogel obtained in the embodiment of the present application.

[0023] Figure 5A flow cytometry result diagram of the hydrogel obtained in the embodiment of the present application for regulating macrophage M1 and M2 polarization.

[0024] Figure 6 A result diagram of the hydrogel obtained in the embodiment of the present application for promoting wound healing rate. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0026] The present application provides an antibacterial and immune regulation hydrogel, which comprises oDex (obtained by oxidizing dextran with NaIO4), EPL, TA and Fe 3+ , and is synthesized based on the Schiff base bond of oDex and EPL, the ionic bond and hydrogen bond of TA and EPL, and the coordination action of TA and Fe 3+ .

[0027] The oDex comprises the following preparation steps: 2 g of Dex with a molecular weight of 20,000-70,000 Da is dissolved in 20 mL of deionized water, respectively; 1.28-2.56 g of NaIO4 is dissolved in 12-24 mL of deionized water; the NaIO4 solution is added dropwise into the Dex solution, and the reaction is stirred at room temperature for 1-4 h, then 1 mL of ethylene glycol is added dropwise to terminate the reaction, and the oDex is prepared by dialysis in deionized water and freeze-drying.

[0028] In the preparation process of the oDex, the molecular weight of Dex is preferably 20,000-70,000 Da, and more preferably 70,000 Da; the mass ratio of NaIO4 to Dex is 0.64-1.28:1, and more preferably 0.96:1. The volume of deionized water is 12-24 mL, and more preferably 18 mL. The reaction time is preferably 1-4 h, and more preferably 4 h. Then the oDex is prepared by dialysis in deionized water and freeze-drying.

[0029] The hydrogel comprises the following preparation steps:

[0030] S1, oDex, EPL, TA and FeCl3·6H2O were dissolved in phosphate buffer (pH 7.4) respectively;

[0031] S2, oDex, EPL and TA were stirred and mixed uniformly, and FeCl3·6H2O solution was added;

[0032] S3, 1 M NaOH was added dropwise to the solution obtained in step S2, and the hydrogel was prepared at 37 ℃.

[0033] According to the present application, the oDex concentration in the preparation of the hydrogel is preferably 1-7 w / v %, more preferably 7 w / v %. The EPL molecular weight is preferably 2,000-5,000 Da, more preferably 5,000 Da. The EPL concentration is preferably 1-4 w / v %, more preferably 4 w / v %. The TA concentration is preferably 0-1 w / v %, more preferably 0 w / v % (OE), 0.5 w / v % (OETF5) and 1 w / v % (OETF 10 ). 3+ The Fe concentration is preferably 0-0.3 w / v %, more preferably 0.15 w / v %. The 1 M NaOH addition amount is preferably 0-20 µL, more preferably 15 µL (OETF5) and 20 µL (OETF 10 ), and finally three hydrogels are obtained, which are named OE, OETF5 and OETF 10 according to the TA concentration.

[0034] According to the present application, the near-infrared laser wavelength for the photo-thermal assisted antibacterial function of the hydrogel is preferably 808 nm. The near-infrared laser power is preferably 0.5-1.5 W / cm 2 , more preferably 1 W / cm 2 . The near-infrared laser working time is preferably 1-10 min, more preferably 5 min.

[0035] In the embodiments of the present application, the following is carried out:

[0036] 1) Antibacterial experiment: In the present application, Escherichia coli (labeled as E. coli in the result figure), Staphylococcus aureus (labeled as S. aureus in the result figure) and methicillin-resistant Staphylococcus aureus (labeled as MRSA in the result figure) are selected to study the antibacterial activity of the hydrogel, and LB medium is preferably used for bacterial culture; the bacterial liquid concentration is preferably 1 × 10 6 ~1 ×10 8 cfc / mL, more preferably 1 × 10 8cfu / mL; the co-culturing time of the hydrogel with the bacterial solution is preferably 0.5-4 h, more preferably 0.5 h; preferably, the hydrogel is irradiated with 808 nm near-infrared laser, and the power is preferably 0.5-1.5 W / cm 2 , more preferably 1 W / cm 2 ; the irradiation time is preferably 1-10 min, more preferably 5 min; preferably, the antibacterial ability of the hydrogel is studied by the plate counting method, and the dilution multiple of the bacterial solution is preferably 100-10,000, more preferably 10,000; the volume of the plated bacterial solution is preferably 30-50 μL, more preferably 30 μL; the culture condition is preferably 37 ℃ culture for 16-20 h, and the colony growth is observed and recorded for evaluating the antibacterial activity of the hydrogel.

[0037] 2) Cell culture: in the present application, the RAW 264.7 cell line is selected, and the cells are cultured in DMEM medium containing 10% fetal bovine serum, and the culture condition is preferably carried out in a carbon dioxide incubator with a volume fraction of 5%, and the culture temperature is preferably 37 ℃.

[0038] 3) Cytotoxicity: in the present application, the L929 cell line is selected for cytotoxicity evaluation. The L929 cell density is 5×10 3 / cm2, and the cells are planted in a 96-well plate and cultured overnight. The hydrogel extract is added to the well plate and incubated with the cells for 24 h and 72 h, and then the hydrogel extract is washed away with PBS and fresh culture medium is added, and finally 20 μL of MTT solution is added to each well, and the incubation is continued for 4 h, and then 150 μL of DMSO is added to each well, and the well plate is gently shaken, and the absorbance value of each well is detected by an enzyme-labeled instrument at 492 nm. The cell survival rate is calculated by the following formula.

[0039] Cell survival rate (%) = (A sample / A blank) × 100;

[0040] 4) Cell level anti-inflammatory and antioxidant: in the present application, the cell level anti-inflammatory and antioxidant (the intracellular reactive oxygen species level is detected by the DCFH-DA fluorescent probe) treatment preferably uses the RAW 264.7 cell line, and the RAW 264.7 cell density is 1×10 4 / cm2, and the cells are planted in a 96-well plate and cultured overnight. The model group and the hydrogel treatment group are respectively co-incubated with lipopolysaccharide (LPS) with a concentration of 1-5 μg / mL for 6-24 h. The LPS concentration is preferably 1 μg / mL, and the stimulation time is preferably 24 h.

[0041] 5) Cell level M1 / M2 polarization regulation: in the present application, the cell level M1 / M2 polarization regulation preferably uses the RAW 264.7 cell line, and the RAW 264.7 cell density is 1×105 The holes are planted in a 24-well plate and cultured overnight. The model group and the hydrogel treatment group are respectively incubated with lipopolysaccharide (LPS) at a concentration of 1-5 μg / mL for 6-24 h. The LPS concentration is preferably 1 μg / mL, and the stimulation time is preferably 24 h. The expression levels of M1 marker CD86 and M2 marker CD206 are detected by flow cytometry to evaluate the regulation function of the hydrogel on the M1 / M2 polarization of macrophages.

[0042] 6) Animal model: In the present application, male C57 BL / 6 mice are selected, and streptozotocin (STZ) is used to induce a diabetic model, and the STZ concentration is preferably 150-200 mg / kg, and more preferably 180 mg / kg; Staphylococcus aureus is used to induce a diabetic local wound infection model, and the Staphylococcus aureus concentration is preferably 1 × 10 5 ~1 × 10 8 cfu / mL, and more preferably 1 × 10 8 cfu / mL, and the volume of the bacterial solution is preferably 10-40 μL, and more preferably 40 μL. After inoculating the bacterial solution, drug treatment experiments of different groups are started.

[0043] In order to facilitate those skilled in the art to better understand the technical scheme of the present application, the following specific embodiments of the present application are given:

[0044] The reagents used in the following examples are all commercially available.

[0045] Examples 1-36

[0046] The present application provides a preparation method of an antibacterial and immune regulation hydrogel, which comprises the following steps:

[0047] oDex comprises the following preparation steps: 2 g of Dex with a molecular weight of 70,000 Da is dissolved in 20 mL of deionized water; 1.92 g of NaIO4 is dissolved in 18 mL of deionized water; the NaIO4 solution is added dropwise to the Dex solution, stirred at room temperature for 4 h, then 1 mL of ethylene glycol is added to terminate the reaction, and oDex is prepared by dialysis in deionized water and freeze-drying.

[0048] oDex, EPL, TA and FeCl3·6H2O are respectively dissolved in phosphate buffer (pH 7.4); oDex, EPL and TA are stirred and mixed uniformly, and FeCl3·6H2O solution is added; 1 M NaOH is added dropwise to the above solution, and the hydrogel is prepared at 37 ℃.

[0049] In the hydrogel preparation process, oDex with a preferred concentration of 1-7 w / v%, EPL with a preferred molecular weight of 5,000 Da and a preferred concentration of 1-4 w / v%, TA with a preferred concentration of 0-1 w / v%, and Fe with a preferred concentration of 0-0.15 w / v% are used. 3+ Mix thoroughly; add 0-20 µL of 1 M NaOH to obtain three hydrogels, which are named OE, OETF5, and OETF according to their TA concentrations. 10 Among them, oDex, EPL, TA, and Fe 3+ The amounts of NaOH used are shown in Table 1.

[0050] Table 1. Dosage of different raw materials in Examples 1-36

[0051]

[0052] The hydrogels prepared in Examples 12, 24, and 36 were analyzed using scanning electron microscopy (SEM), and the SEM images were obtained. Based on the TA concentration, they were named OE, OETF5, and OETF, respectively. 10 . Figure 1 Scanning electron microscope images of the hydrogels prepared in Examples 12, 24 and 36, as shown below. Figure 1 As shown, the results indicate that the hydrogels prepared in Examples 12, 24 and 36 all have interconnected porous microstructures, and the pore size of the hydrogels decreases with increasing TA concentration.

[0053] Experimental Example 1

[0054] For the PBS control group and the Met treatment group, the concentration was 1×10 8 cfu / mL of E. coli (marked in the results figure) E. coli Staphylococcus aureus (marked as in the results image) S. aureus ) and methicillin-resistant Staphylococcus aureus (marked as in the results figure) MRSA (100 μL) was co-incubated with PBS and methicillin (Met) at a final concentration of 128 μg / mL for 0.5 h, respectively; for the hydrogel treatment group, 100 μL of bacterial solution was added dropwise to OE, OETF5 and OETF5, respectively. 10 Co-culture on the hydrogel surface for 0.5 h, OETF 10 The power used in the +NIR treatment group was 1 W / cm². 2 808 nm near-infrared laser irradiation of OETF 10 After hydrogelation for 5 min, incubation was continued for 0.5 h. The bacterial suspension was diluted 10,000-fold with sterile PBS, and the antibacterial activity of the hydrogel was studied using the plate count method. 30 μL of the diluted bacterial suspension was plated and incubated at 37 ℃ for 20 h.Figure 2 As shown, the results indicate that, compared to the PBS control group ( Figure 2 Compared to the control group (labeled as Met in the figure), the Met treatment group (labeled as Met in figure 2) showed a weaker antibacterial effect in a short period of time; while OE, OETF5, and OETF... 10 Hydrogel treatment group ( Figure 2 They are named OE, OETF5, and OETF respectively. 10 It exhibits effective antibacterial activity, and this activity increases with increasing TA concentration; OETF 10 +NIR treatment group ( Figure 2 Named OETF 10 +NIR), after OETF irradiation with 808 nm near-infrared laser 10 Hydrogels can kill more than 90% of bacteria.

[0055] Experiment Example 2

[0056] L929 cell density was set at 5×10⁻⁶. 3 Cells were seeded in 96-well plates and cultured overnight. DMEM medium was used as a negative control. Hydrogel extract was added to each well and incubated for 24 h and 72 h. The hydrogel extract was then washed away with PBS, and fresh medium was added. Finally, 20 μL of MTT solution was added to each well, and incubation continued for 4 h. Then, 150 μL of DMSO was added to each well, and the plate was gently shaken. The absorbance of each well was measured at 492 nm using a microplate reader. Cytotoxicity was calculated according to Formula 1. Figure 3 As shown, the results indicate that, compared with the control group ( Figure 3 Compared to OE, OETF5, and OETF (named Control in Chinese), 10 ( Figure 3 They are named OE, OETF5, and OETF respectively. 10 All hydrogels exhibit good biocompatibility.

[0057] Formula 1: Cell viability (%) = (Absorbance of treatment group / Absorbance of control group) × 100%;

[0058] Experimental Example 3

[0059] RAW 264.7 cells were spaced at a density of 1×10⁻⁶ cells. 4 RAW 264.7 cells were seeded in 96-well plates and cultured overnight. The LPS model group was co-incubated with 1 μg / mL LPS for 24 h, while the hydrogel treatment group received OE, OETF5, and OETF... 10 RAW 264.7 cells were co-treated with 1 μg / mL LPS for 24 h using hydrogel extract. Figure 4As shown in Figure A, the results indicate that, compared to the control group of normal cells ( Figure 4 Compared to the Control model group (named Control), the LPS model group ( Figure 4 The oxidative stress level (DCFH-DA fluorescence intensity) of the model group (named LPS) was significantly increased; compared with the LPS model group, OE, OETF5, and OETF were significantly increased. 10 Hydrogel treatment group ( Figure 4 They are named OE, OETF5, and OETF respectively. 10 The oxidative stress level (DCFH-DA fluorescence intensity) was significantly reduced. For example... Figure 4 As shown in BD, the results indicate that, compared to the control group of normal cells ( Figure 4 Compared to the control group, the LPS model group showed significantly increased levels of pro-inflammatory cytokines; compared to the LPS model group (named Control), the pro-inflammatory cytokine levels were significantly increased. Figure 4 Compared to LPS (named LPS in Chinese), OE, OETF5, and OETF 10 Hydrogel treatment group ( Figure 5 They are named OE, OETF5, and OETF respectively. 10 The levels of pro-inflammatory factors TNF-α, IL-6, and IL-1β in the cell supernatant of the hydrogel were significantly reduced, and the anti-inflammatory and antioxidant activities of the hydrogel were enhanced with the increase of TA concentration in the hydrogel.

[0060] Experiment Example 4

[0061] RAW 264.7 cells were spaced at a density of 1×10⁻⁶ cells. 5 RAW 264.7 cells were seeded in 24-well plates and cultured overnight. The LPS model group was co-incubated with 1 μg / mL LPS for 24 h, while the hydrogel treatment group received OE, OETF5, and OETF5. 10 RAW 264.7 cells were co-treated with 1 μg / mL LPS for 24 h using hydrogel extract. The regulatory function of the hydrogel on macrophage M1 / M2 polarization was evaluated by flow cytometry analysis of the expression levels of the M1 marker CD86 and the M2 marker CD206. Figure 5 As shown, the results indicate that, compared with the control group of normal cells ( Figure 5 Compared to the Control model group (named Control), the LPS model group ( Figure 5 The expression levels of CD86 (named LPS) were significantly increased, while the expression levels of CD206 were decreased, indicating significant M1 polarization; compared with the LPS model group, OE, OETF5, and OETF... 10 Hydrogel treatment group ( Figure 6 They are named OE, OETF5, and OETF respectively. 10The decreased expression of the M1 marker CD86 and the increased expression of the M2 marker CD206 indicate that the hydrogel has an effective immunomodulatory function, and the immunomodulatory ability of the hydrogel is enhanced with the increase of TA concentration.

[0062] Experimental Example 5

[0063] A diabetes model was induced in male C57 BL / 6 mice by intraperitoneal injection of STZ at a concentration of 180 mg / kg. A circular wound with a diameter of 8 mm was created on the back of the mouse, and 40 μL of a 1 × 10⁻⁶ STZ solution was dripped into the wound. 8 A localized wound infection model of diabetes was established using Staphylococcus aureus at cfu / mL. After inoculation with the bacterial solution, drug treatment experiments were conducted on different hydrogel groups. PBS treatment served as the negative control group. Figure 6 The membrane was named Control in China, and the commercially available Tegaderm membrane was used as the positive control group. Figure 6 (named Tegaderm in Chinese), using OE and OETF. 10 Hydrogel as a treatment group ( Figure 6 They are named OE and OETF respectively. 10 The administration method involved dripping PBS onto the wound surface; sealing the wound with a Tegaderm membrane; applying different hydrogels to the wound surface, administering the medication every two days, and recording the wound area. For example... Figure 6 As shown, the results indicate that, compared to the negative control group ( Figure 6 Compared to the control group (named Control), the positive control group ( Figure 6 The treatment, named Tegaderm in China, has a weaker effect and cannot promote wound healing; while OE and OETF... 10 Treatment group ( Figure 6 They are named OE and OETF respectively. 10 It can effectively promote the healing of diabetic infected wounds, and the healing speed increases with the increase of TA concentration. Under the assistance of photothermal therapy, using a power of 1 W / cm 2 OETF irradiated with 808 nm near-infrared light 10 Hydrogel 5 min as OETF 10 +NIR treatment group, OETF 10 +NIR treatment group ( ​ Named OETF 10 The wound was almost completely healed after 14 days of treatment (+NIR).

[0064] The present invention provides a hydrogel with antibacterial, antioxidant, anti-inflammatory, and immunomodulatory functions. This hydrogel has advantages such as ease of handling and low cost. The hydrogel is formed by Schiff base bonds between oDex and EPL, ionic and hydrogen bonds between TA and EPL, and bonds between TA and Fe. 3+The hydrogel is prepared by coordination of EPL and TA; the hydrogel plays an antibacterial role by releasing EPL, TA and combining with photothermal therapy (PTT); the hydrogel can clear excessive RONS at the infection site by releasing TA, can reduce the oxidative stress level at the infection site, and can reduce the production of inflammatory factors; the hydrogel can regulate macrophage phenotype polarization, balance M1 / M2 cell levels, and promote cell proliferation, and can effectively treat diabetic bacterial infection wound healing.

[0065] It should be noted that in this text, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "includes a …" does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

Claims

1. Use of a hydrogel in the preparation of a wound healing material for the treatment of diabetic bacterial infections, characterized in that, The hydrogel comprises oDex, EPL, TA and Fe 3+ , a Schiff base bond based on oDex and EPL, an ionic bond and a hydrogen bond based on TA and EPL, and a coordination action of TA and Fe 3+ Three hydrogels with photo-thermal assisted antibacterial, antioxidant, anti-inflammatory and immune regulation functions can be obtained; wherein, the oDex is obtained by oxidizing dextran with NaIO4; The preparation method of the hydrogel comprises the following steps: S1, oDex, EPL, TA and FeCl3·6H2O are respectively dissolved in a phosphate buffer solution; S2, oDex, EPL and TA are stirred and mixed uniformly, and FeCl3·6H2O solution is added; S3, 1 M NaOH is added dropwise to the solution obtained in step S2, and the hydrogel is prepared at 37 DEG C; The TA concentration is 0.5-1 w / v %; the 1 M NaOH addition amount is 15-20 µL; The oDex concentration was 7 w / v %, the EPL molecular weight was 5,000 Da, the EPL concentration was 4 w / v %, Fe 3+ concentration was 0.15 w / v %. The oDex is prepared by sodium periodate oxidation of dextran; the molecular weight of the dextran is 20,000-70,000 Da; the mass ratio of NaIO4 to dextran is 0.64-1.28:1; The preparation steps of the oDex are as follows: Dex 2 g with a molecular weight of 20,000-70,000 Da is dissolved in 20 mL of deionized water to obtain a Dex solution; 1.28-2.56 g of NaIO4 is dissolved in 12-24 mL of deionized water to obtain a NaIO4 solution; The NaIO4 solution is added dropwise to the Dex solution, stirred at room temperature for 1-4 h, then 1 mL of ethylene glycol is added dropwise to terminate the reaction, and the oDex is prepared by dialysis in deionized water and freeze-drying.

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