Ruthenium complex MXene chitosan composite antibacterial hydrogel as well as preparation method and application thereof

Abstract

The invention relates to the technical field of new material synthesis and medical antibacterial materials, in particular to ruthenium complex MXene chitosan composite antibacterial hydrogel as well as a preparation method and application thereof. According to the preparation method, carboxymethyl chitosan, tannic acid and a quaternized ruthenium complex MXene composite material are used for constructing a triple functional composite hydrogel system by adopting a rapid mixing one-step method, and the preparation method can complete gelation at room temperature within 30 seconds to prepare the ruthenium complex MXene chitosan composite antibacterial hydrogel. The prepared ruthenium complex MXene chitosan composite antibacterial hydrogel has multiple synergistic antibacterial mechanisms, the antibacterial effect can be synergistically exerted through the chemical action of quaternary ammonium salt, the physical cutting and photothermal effects of MXene and the photodynamic action of the ruthenium complex, the antibacterial ability is remarkably enhanced through the combination of the multiple action mechanisms, and the hydrogel has a good antibacterial effect. The antibacterial activity is stable and efficient. The ruthenium complex MXene chitosan composite antibacterial hydrogel has a good application prospect in preparation of medical antibacterial drugs and wound repair materials.

Description

Technical Field

[0001] This invention relates to the fields of new material synthesis and medical antibacterial materials technology, specifically to a ruthenium complex MXene chitosan composite antibacterial hydrogel and its preparation method and application. Background Technology

[0002] With the accelerating rate of bacterial mutation and the increasing severity of antibiotic overuse, the development of novel antibacterial materials has become an urgent need in scientific research and the medical field. The single-mechanism action of traditional antibacterial drugs easily leads to bacterial resistance, resulting in a gradual decline in treatment efficacy and even the threat of "superbugs." Single antibacterial components suffer from low antibacterial efficiency; currently, most antibacterial materials rely on only a single antibacterial mechanism, such as simple chemical sterilization or physical contact. This single-mode of action is ineffective and its antibacterial efficiency significantly decreases under complex physiological environments. Traditional hydrogels, as antibacterial materials, suffer from insufficient mechanical properties. This mechanical deficiency causes structural collapse in wound dressing applications, making it impossible to maintain a stable three-dimensional scaffold structure, affecting nutrient delivery and reducing the stability of the drug delivery system.

[0003] Therefore, in recent years, the research and development of multifunctional composite antibacterial materials has attracted much attention and become a key direction for solving this problem. Multifunctional composite antibacterial materials, by organically combining multiple antibacterial components or mechanisms, can exert synergistic antibacterial effects, inhibiting or killing bacteria through multiple pathways, thereby effectively reducing the risk of bacterial resistance. This multi-layered antibacterial mechanism not only achieves highly efficient bactericidal effects at low concentrations but also reduces toxicity to host cells and improves biocompatibility.

[0004] However, the existing processes for preparing multifunctional composite antibacterial materials are relatively complex, and the gelation process is time-consuming, resulting in slow production efficiency. Furthermore, the antibacterial activity and antibacterial capacity of existing multifunctional composite antibacterial materials need further improvement. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the first objective of this invention is to provide a method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel. This method constructs a triple-functionalized composite hydrogel system through a rapid one-step mixing process, which shortens the gelation time. The resulting composite antibacterial hydrogel possesses multiple synergistic antibacterial mechanisms, significantly enhances antibacterial ability, and exhibits stable and efficient antibacterial activity.

[0006] To overcome the shortcomings of the prior art, the second objective of this invention is to provide a ruthenium complex MXene chitosan composite antibacterial hydrogel, which possesses multiple synergistic antibacterial mechanisms, significantly enhances antibacterial ability, and exhibits stable and efficient antibacterial activity.

[0007] The third objective of this invention is to provide an application of a ruthenium complex MXene chitosan composite antibacterial hydrogel.

[0008] To achieve the first objective of the invention, the technical solution adopted by the present invention is as follows:

[0009] This invention provides a method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel, comprising the following steps:

[0010] S1. Preparation of ruthenium precursor: Ruthenium salt, 2,2-bipyridine and lithium chloride were dissolved in an organic solvent and heated under reflux in an inert atmosphere. After filtration and washing, the ruthenium precursor was obtained.

[0011] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an inert atmosphere. Then the temperature was raised and the stirring was continued. The ligands were obtained after filtration, washing and drying.

[0012] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 are dissolved in a solvent, heated under reflux and stirred to react, cooled, separated and purified, and the solvent is removed to obtain the ruthenium complex.

[0013] S4. Synthesis of quaternary ruthenium complex: The ruthenium complex was dissolved in iodomethane in a solvent, heated under reflux and stirred to react, and then the solvent was removed to obtain the quaternary ruthenium complex;

[0014] S5. Preparation of MXene quaternary ruthenium complex: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets, and the mixture was stirred and reacted at room temperature in the dark under an inert atmosphere. After washing and drying, the MXene quaternary ruthenium complex was obtained.

[0015] S6. Preparation of composite antibacterial hydrogel: Carboxymethyl chitosan, tannic acid, and the quaternary ammonium ruthenium complex MXene composite material obtained in step S5 are dissolved in water, stirred and mixed to obtain a mixture, and allowed to stand to obtain the ruthenium complex MXene chitosan composite antibacterial hydrogel.

[0016] This invention discloses a method for preparing a ruthenium complex MXene-chitosan composite antibacterial hydrogel. The method uses carboxymethyl chitosan (CMCS), which exhibits excellent biocompatibility, as the matrix material. Dynamic covalent cross-linking is achieved by utilizing the polyphenolic hydroxyl properties of tannic acid (TA). Simultaneously, a quaternized ruthenium complex MXene composite material (Q / Ru-MXene) is uniformly dispersed within the network structure as a multifunctional pharmaceutical additive. The carboxymethyl chitosan, tannic acid, and the quaternized ruthenium complex MXene composite material are constructed using a "rapid mixing one-step method" to create a triple-functionalized composite hydrogel system. This preparation method allows gelation to be completed within 30 seconds at room temperature, yielding the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene). The prepared ruthenium complex MXene-chitosan composite antibacterial hydrogel possesses multiple synergistic antibacterial mechanisms. Through the chemical action of quaternary ammonium salt, the physical cleavage and photothermal effect of MXene, and the photodynamic effect of ruthenium complex, the antibacterial effect can be exerted synergistically. The combination of this multiple mechanism significantly enhances the antibacterial ability.

[0017] Further, in step S1, the molar volume ratio of the ruthenium salt, 2,2-bipyridine, lithium chloride, and organic solvent is (6–9) mmol:(13–17) mmol:(18–22) mmol:(8–12) mL; and / or

[0018] The ruthenium salt is RuCl3-3H2O; and / or, the organic solvent is N,N-dimethylformamide; and / or

[0019] Ruthenium salt, 2,2-bipyridine, and lithium chloride were dissolved in an organic solvent and refluxed at 75°C–85°C for 10–14 h under an argon atmosphere. After cooling to room temperature, acetone was added, and the mixture was then frozen at -18°C–22°C for 10–15 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor. The volume ratio of acetone added after cooling to room temperature to the organic solvent was (4–6):1.

[0020] In the preparation of the ruthenium precursor, the filtrate was washed with acetone until it was almost colorless, and the ruthenium precursor was obtained as dark green crystals, denoted as (bpy)2RuCl2·2H2O crystals. The crystals were then stored in a vacuum desiccator.

[0021] Further, in step S2, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine is (0.3–0.7) mmol:(13–17) mL; and / or

[0022] 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 25-35 minutes. A milky white insoluble substance was observed at this point. The temperature was then raised to 55-65°C, and the reaction was continued with stirring for 4-6 hours. After cooling to room temperature, the ligand was obtained by filtration, washing with ice-cold ethanol, and vacuum drying. The obtained ligand was a pale pink solid.

[0023] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 75℃~85℃ for 22h~26h. Then, it is placed in a fume hood and dried for 10h~15h to volatilize the excess sulfoxide, thereby obtaining 2,2-bipyridine-4,4-dicarboxylic acid.

[0024] In the synthesis of 2,2-bipyridine-4,4-dicarboxylic acid chloride, sulfoxide is freshly distilled sulfoxide, i.e., sulfoxide that has just been purified by distillation. Furthermore, the obtained 2,2-bipyridine-4,4-dicarboxylic acid chloride is a milky yellow product.

[0025] Further, in step S3, the molar volume ratio of the ligand, ruthenium precursor, and solvent is (0.1–0.4) mmol:(0.1–0.4) mmol:(25–35) mL; and / or

[0026] The solvent is anhydrous ethanol; and / or

[0027] The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in a solvent and reacted under reflux at 75℃~85℃ for 10h~14h. After cooling to room temperature, the mixture was purified by silica gel column chromatography, and the solvent was removed by rotary evaporation to obtain the ruthenium complex. The obtained ruthenium complex was an orange-red crystal.

[0028] Further, in step S4, the molar volume ratio of the ruthenium complex, iodomethane, and solvent is (0.05–0.15) mmol:(0.1–0.3) mmol:(25–35) mL; and / or

[0029] The solvent is anhydrous ethanol; and / or

[0030] The ruthenium complex was dissolved in iodomethane and the mixture was heated under reflux at 75°C–85°C with stirring for 10–14 hours. The solvent was then removed by rotary evaporation to obtain the quaternized ruthenium complex. The obtained quaternized ruthenium complex was a deep red crystal.

[0031] Further, in step S5, the MXene nanosheets are prepared by: adding Ti3AlC2 ceramic powder to the etchant, heating and stirring at 45℃~55℃ for 20h~30h, centrifuging and washing with deionized water until the pH of the supernatant is 7 to obtain a suspension, then subjecting the suspension to ultrasonic oscillation in an ice bath for 2.5h~3.5h, followed by vacuum freeze-drying to obtain monolayer MXene nanosheets; and / or

[0032] The etchant is prepared by mixing 10M-14M HCl solution with LiF; the volume-to-mass ratio of the HCl solution to LiF is (35-45) mL:(2-5) g; and / or

[0033] The Ti3AlC2 ceramic powder has a particle size of 150 mesh to 250 mesh; and / or

[0034] The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is (40-50) mL:(1-3) g.

[0035] Furthermore, in step S5, the volume ratio of the quaternary ruthenium complex to the MXene nanosheet aqueous solution is (0.5–2):(0.5–2); and / or

[0036] In the aqueous solution of MXene nanosheets, the mass concentration of MXene nanosheets is 2 mg / mL to 8 mg / mL; and / or

[0037] The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 10-15 hours. The mixture was then washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material.

[0038] In the preparation of the quaternary ruthenium complex MXene composite material, since the surface of the synthesized quaternary ruthenium complex is positively charged, the surface of the MXene nanosheets is modified by the electrostatic interaction between the quaternary ruthenium complex and the MXene nanosheets, thus obtaining the quaternary ruthenium complex MXene composite material.

[0039] Further, in step S6, the mass concentration of carboxymethyl chitosan in the mixed liquid system is 2.5%–3.5%, the mass concentration of tannic acid in the mixed liquid system is 3.5%–4.5%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixed liquid system is 0.2%–0.8%; and / or

[0040] Carboxymethyl chitosan, tannic acid, and the quaternary ammonium ruthenium complex MXene composite material obtained in step S5 were dissolved in deionized water, and then stirred and mixed for 20 to 30 seconds to obtain a mixture. After standing for 4 to 5 minutes, the ruthenium complex MXene chitosan composite antibacterial hydrogel was obtained.

[0041] To achieve the second objective of the invention, the technical solution adopted by the present invention is as follows:

[0042] This invention provides a ruthenium complex MXene-chitosan composite antibacterial hydrogel, which is prepared by the above-described method for preparing a ruthenium complex MXene-chitosan composite antibacterial hydrogel.

[0043] To achieve the third objective of the invention, the technical solution adopted by the present invention is as follows:

[0044] This invention provides an application of a ruthenium complex MXene-chitosan composite antibacterial hydrogel, specifically the application of the ruthenium complex MXene-chitosan composite antibacterial hydrogel prepared by the above-described method in the preparation of medical antibacterial drugs and wound repair materials.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] (1) A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel of the present invention uses carboxymethyl chitosan (CMCS) with excellent biocompatibility as the matrix material and tannic acid (TA) as the crosslinking agent. The polyphenolic hydroxyl properties of tannic acid are utilized to achieve physical crosslinking through dynamic imine bonds and hydrogen bonds, and dynamic covalent crosslinking is achieved. At the same time, the quaternized ruthenium complex MXene composite material (Q / Ru-MXene) is uniformly dispersed in the network structure as a multifunctional drug additive. The carboxymethyl chitosan, tannic acid and quaternized ruthenium complex MXene composite material are constructed into a triple functionalized composite hydrogel system by a "rapid mixing one-step method". This preparation method can complete gelation within 30 seconds at room temperature to obtain the ruthenium complex MXene chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene). The prepared ruthenium complex MXene-chitosan composite antibacterial hydrogel possesses multiple synergistic antibacterial mechanisms. Through the chemical action of quaternary ammonium salt, the physical cleavage and photothermal effect of MXene, and the photodynamic effect of ruthenium complex, the antibacterial effect can be exerted synergistically. The combination of this multiple mechanism significantly enhances the antibacterial ability.

[0047] (2) The present invention provides a method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel. The method constructs a triple functionalized composite hydrogel system through a rapid mixing one-step method. The gelation time is short, and the prepared composite antibacterial hydrogel has multiple synergistic antibacterial mechanisms, significantly enhances antibacterial ability, and has stable and efficient antibacterial activity.

[0048] (3) The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel of the present invention is simple and convenient in synthesis process, can be mass-produced without cumbersome operation process, and is economical in cost.

[0049] (4) The ruthenium complex MXene chitosan composite antibacterial hydrogel of the present invention has a network cross-linked structure with dense pores inside, good swelling properties, good biocompatibility, can effectively remove reactive oxygen species, and has a certain hemostatic ability.

[0050] (5) The application of a ruthenium complex MXene-chitosan composite antibacterial hydrogel of the present invention, wherein the ruthenium complex MXene-chitosan composite antibacterial hydrogel is used in the preparation of medical antibacterial drugs and wound repair materials. The ruthenium complex MXene-chitosan composite antibacterial hydrogel has injectability, self-healing and tissue adhesion, which enables it to adapt to the shape of complex wounds and closely adhere to the wound surface, and can realize on-demand drug release. By loading the quaternized ruthenium complex MXene composite material, not only is the hydrogel endowed with significant photothermal conversion ability, but also a triple synergistic antibacterial effect is achieved through the contact bactericidal effect of quaternary ammonium salt groups, the photodynamic effect of ruthenium complex and the physical cutting effect of MXene, exhibiting stable and efficient antibacterial activity. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0052] Figure 1 This is a synthetic route diagram of the quaternized ruthenium complex in Example 1 of the present invention.

[0053] Figure 2 This is a SEM image of the monolayer MXene nanosheets prepared in Example 1 of this invention.

[0054] Figure 3 This is a SEM image of a ruthenium complex MXene chitosan composite antibacterial hydrogel according to Example 1 of the present invention.

[0055] Figure 4 This is a graph showing the cumulative release rate of the hydrogels prepared in Example 1 and Comparative Example 1 of the present invention under acidic environment and near-infrared laser response.

[0056] Figure 5 The graph shows the cumulative release rate of the ruthenium complex MXene chitosan composite antibacterial hydrogel of Example 1 of this invention under acidic conditions with different power densities of near-infrared laser irradiation and under no light conditions.

[0057] Figure 6 This is a graph showing the cumulative release rate of the ruthenium complex MXene chitosan composite antibacterial hydrogel of Example 1 of the present invention under different pH conditions after irradiation with a 1.0W near-infrared laser.

[0058] Figure 7 This is a graph showing the cumulative release rate of the ruthenium complex MXene chitosan composite antibacterial hydrogel of Example 1 of the present invention under different pH conditions without near-infrared laser irradiation.

[0059] Figure 8 This is a graph showing the cumulative release rate of the ruthenium complex MXene chitosan composite antibacterial hydrogel of Example 1 of the present invention after being released for 15 minutes under different pH conditions and then subjected to near-infrared laser irradiation for 15 minutes.

[0060] Figure 9 The graph shows the results of testing the relationship between the apparent viscosity and shear rate of the four hydrogels in Example 1 and Comparative Examples 1-3 using a rheometer.

[0061] Figure 10 This is a test result showing that the ruthenium complex MXene chitosan composite antibacterial hydrogel of Example 1 was injected with a needle to write patterns and quickly returned to the gel state after injection.

[0062] Figure 11 This is a graph showing the self-healing process of the ruthenium complex MXene chitosan composite antibacterial hydrogel of Example 1 of the present invention.

[0063] Figure 12 This is a graph showing the adhesion test results of the ruthenium complex MXene chitosan composite antibacterial hydrogel of Embodiment 1 of the present invention on different substrates.

[0064] Figure 13 The graph shows the test results of the force exerted on pigskin by four types of hydrogels at different times in Example 1 and Comparative Examples 1-3.

[0065] Figure 14 The graph shows the test results of the bonding strength of four hydrogels to pigskin in Example 1 and Comparative Examples 1-3.

[0066] Figure 15The graph shows the temperature change of four hydrogels (Example 1 and Comparative Examples 1-3) after irradiation with a 1.0W near-infrared laser for 5 minutes and then the laser was turned off for 5 minutes.

[0067] Figure 16 The graph shows the temperature change of the hydrogel in Example 1 after being irradiated with near-infrared laser at different power densities for 5 minutes and then turned off for 5 minutes.

[0068] Figure 17 This is a temperature change curve of the hydrogel in Example 1 under three on / off cycles of a 1.0W near-infrared laser.

[0069] Figure 18 The graph shows the scavenging rate of DPPH free radicals of four hydrogels in Example 1 and Comparative Examples 1-3.

[0070] Figure 19 The graph shows the scavenging rate of hydroxyl radicals of the four hydrogels in Example 1 and Comparative Examples 1-3.

[0071] Figure 20 These are fluorescence images of WI38 cells after treatment with four different hydrogels: one without H2O2 (control group), one with 1mM H2O2, and two hydrogels (Example 1 and Comparative Examples 1-3) and stained with DCFH-DA.

[0072] Figure 21 The graph shows the inhibition of Escherichia coli colony growth by four types of hydrogels in Example 1 and Comparative Examples 1-3 under no light and 1.0W near-infrared laser irradiation for 5 min.

[0073] Figure 22 This is a graph showing the detection results of the diameter of the inhibition zone formed by the four hydrogels in Example 1 and Comparative Examples 1-3 after incubating Escherichia coli colonies for 12 hours.

[0074] Figure 23 The graph shows the inhibition of Escherichia coli colony growth by four different Q / Ru loading hydrogels under no light and 1.0W near-infrared laser irradiation for 5 min.

[0075] Figure 24 This is a graph showing the detection results of the diameter of the inhibition zone formed by four hydrogels with different Q / Ru loadings after incubating E. coli colonies for 12 hours.

[0076] Figure 25 The graph shows the BCI index detection results for four types of hydrogels in Example 1, Comparative Examples 1-3, and the blank control group.

[0077] Figure 26 This is a graph showing the detection results of hemolysis rate for four types of hydrogels in Example 1, Comparative Examples 1-3, and the blank control group.

[0078] Figure 27 These are the hemolysis detection graphs for four types of hydrogels in Example 1, Comparative Examples 1-3, and the blank control group.

[0079] Figure 28 The graph shows the cell viability test results of WI38 cells using four hydrogel extracts from Example 1, Comparative Examples 1-3, and the blank control group.

[0080] Figure 29 The images show the results of fluorescence staining of live / dead cells after treatment with four types of hydrogel extracts (Example 1, Comparative Examples 1-3, and the blank control group). Detailed Implementation

[0081] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0082] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. In this invention, the singular forms “a,” “the,” and “the” as used in the embodiments and appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0083] The tannic acid mentioned in this invention is also known as tannic acid.

[0084] In this embodiment of the invention, a method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0085] S1. Preparation of ruthenium precursor: Ruthenium salt, 2,2-bipyridine and lithium chloride were dissolved in an organic solvent and heated under reflux in an inert atmosphere. After filtration and washing, the ruthenium precursor was obtained.

[0086] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an inert atmosphere. Then the temperature was raised and the stirring was continued. The ligands were obtained after filtration, washing and drying.

[0087] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 are dissolved in a solvent, heated under reflux and stirred to react, cooled, separated and purified, and the solvent is removed to obtain the ruthenium complex.

[0088] S4. Synthesis of quaternary ruthenium complex: The ruthenium complex was dissolved in iodomethane in a solvent, heated under reflux and stirred to react, and then the solvent was removed to obtain the quaternary ruthenium complex;

[0089] S5. Preparation of MXene quaternary ruthenium complex: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets, and the mixture was stirred and reacted at room temperature in the dark under an inert atmosphere. After washing and drying, the MXene quaternary ruthenium complex was obtained.

[0090] S6. Preparation of composite antibacterial hydrogel: Carboxymethyl chitosan, tannic acid, and the quaternary ammonium ruthenium complex MXene composite material obtained in step S5 are dissolved in water, stirred and mixed to obtain a mixture, and allowed to stand to obtain the ruthenium complex MXene chitosan composite antibacterial hydrogel.

[0091] In some embodiments, in step S1, the molar volume ratio of the ruthenium salt, 2,2-bipyridine, lithium chloride, and organic solvent is (6–9) mmol:(13–17) mmol:(18–22) mmol:(8–12) mL; and / or

[0092] The ruthenium salt is RuCl3-3H2O; and / or, the organic solvent is N,N-dimethylformamide; and / or

[0093] Ruthenium salt, 2,2-bipyridine, and lithium chloride were dissolved in an organic solvent and refluxed at 75°C–85°C for 10–14 h under an argon atmosphere. After cooling to room temperature, acetone was added, and the mixture was then frozen at -18°C–22°C for 10–15 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor. The volume ratio of acetone added after cooling to room temperature to the organic solvent was (4–6):1.

[0094] In some embodiments, in step S2, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine is (0.3–0.7) mmol:(13–17) mL; and / or

[0095] 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 25-35 minutes. The temperature was then raised to 55-65°C, and the reaction was continued with stirring for 4-6 hours. After cooling to room temperature, the ligand was obtained by filtration, washing with ice-cold ethanol, and vacuum drying; and / or

[0096] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 75℃~85℃ for 22h~26h. Then, it is dried in a fume hood for 10h~15h to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0097] In some embodiments, in step S3, the molar volume ratio of the ligand, ruthenium precursor, and solvent is (0.1–0.4) mmol:(0.1–0.4) mmol:(25–35) mL; and / or

[0098] The solvent is anhydrous ethanol; and / or

[0099] The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in a solvent and heated under reflux at 75℃~85℃ for 10h~14h. After cooling to room temperature, the mixture was purified by silica gel column chromatography and the solvent was removed by rotary evaporation to obtain the ruthenium complex.

[0100] In some embodiments, in step S4, the molar volume ratio of the ruthenium complex, iodomethane, and solvent is (0.05–0.15) mmol:(0.1–0.3) mmol:(25–35) mL; and / or

[0101] The solvent is anhydrous ethanol; and / or

[0102] The ruthenium complex was dissolved in iodomethane and heated under reflux at 75°C to 85°C for 10 to 14 hours with stirring. The solvent was then removed by rotary evaporation to obtain the quaternized ruthenium complex.

[0103] In some embodiments, in step S5, the MXene nanosheets are prepared by: adding Ti3AlC2 ceramic powder to an etchant, heating and stirring at 45℃~55℃ for 20h~30h, centrifuging and washing with deionized water until the pH of the supernatant is 7 to obtain a suspension, then subjecting the suspension to ultrasonic oscillation in an ice bath for 2.5h~3.5h, followed by vacuum freeze-drying to obtain monolayer MXene nanosheets; and / or

[0104] The etchant is prepared by mixing 10M-14M HCl solution with LiF; the volume-to-mass ratio of the HCl solution to LiF is (35-45) mL:(2-5) g; and / or

[0105] The Ti3AlC2 ceramic powder has a particle size of 150 mesh to 250 mesh; and / or

[0106] The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is (40-50) mL:(1-3) g.

[0107] In some embodiments, in step S5, the volume ratio of the quaternary ruthenium complex to the MXene nanosheet aqueous solution is (0.5–2):(0.5–2); and / or

[0108] In the aqueous solution of MXene nanosheets, the mass concentration of MXene nanosheets is 2 mg / mL to 8 mg / mL; and / or

[0109] The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 10-15 hours. The mixture was then washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material.

[0110] In some embodiments, in step S6, the mass concentration of carboxymethyl chitosan in the mixed liquid system is 2.5%–3.5%, the mass concentration of tannic acid in the mixed liquid system is 3.5%–4.5%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixed liquid system is 0.2%–0.8%; and / or

[0111] Carboxymethyl chitosan, tannic acid, and the quaternary ammonium ruthenium complex MXene composite material obtained in step S5 were dissolved in deionized water, and then stirred and mixed for 20 to 30 seconds to obtain a mixture. After standing for 4 to 5 minutes, the ruthenium complex MXene chitosan composite antibacterial hydrogel was obtained.

[0112] In this embodiment of the invention, an application of a ruthenium complex MXene-chitosan composite antibacterial hydrogel is described, specifically its application in the preparation of medical antibacterial drugs and wound repair materials.

[0113] The following description is based on specific embodiments.

[0114] Example 1

[0115] A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0116] S1. Preparation of ruthenium precursor: RuCl3-3H2O, 2,2-bipyridine and lithium chloride were dissolved in N,N-dimethylformamide and refluxed at 80°C for 12 h under argon atmosphere. After cooling to room temperature, acetone was added and then the mixture was frozen at -20°C for 12 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor.

[0117] In this embodiment, the molar volume ratio of ruthenium salt, 2,2-bipyridine, lithium chloride and N,N-dimethylformamide is 7.5 mmol:15 mmol:20 mmol:10 mL; the volume ratio of acetone to organic solvent added after cooling to room temperature is 5:1.

[0118] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 30 min. Then, the temperature was raised to 60 °C and the reaction was continued with stirring for 5 h. After cooling to room temperature, the ligands were obtained by filtration, washing with ice-cold ethanol, and vacuum drying. In this example, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine was 0.5 mmol: 15 mL.

[0119] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 80°C for 24 hours. Then it is dried in a fume hood for 12 hours to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0120] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in anhydrous ethanol. The mixture was heated to reflux at 80°C and stirred for 12 h. After cooling to room temperature, the mixture was purified by silica gel column chromatography and the solvent was removed by rotary evaporation to obtain the ruthenium complex. In this embodiment, the molar volume ratio of ligand, ruthenium precursor and anhydrous ethanol was 0.25 mmol:0.25 mmol:30 mL.

[0121] S4. Synthesis of quaternized ruthenium complex: The ruthenium complex and iodomethane were dissolved in anhydrous ethanol, and the mixture was heated under reflux at 80°C with stirring for 12 h. The solvent was then removed by rotary evaporation to obtain the quaternized ruthenium complex, denoted as Q / Ru. In this example, the molar volume ratio of the ruthenium complex, iodomethane, and anhydrous ethanol was 0.1 mmol:0.2 mmol:30 mL. The synthetic route of the quaternized ruthenium complex is as follows: Figure 1 As shown.

[0122] S5. Preparation of quaternary ruthenium complex MXene composite material: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 12 h. Then, the mixture was washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material, denoted as Q / Ru-MXene. In this embodiment, the volume ratio of the quaternary ruthenium complex to the aqueous solution of MXene nanosheets was 1:1; the mass concentration of MXene nanosheets in the aqueous solution of MXene nanosheets was 5 mg / mL.

[0123] The preparation method of MXene nanosheets is as follows: Ti3AlC2 ceramic powder with a particle size of 200 mesh is added to an etchant, and the mixture is heated and stirred at 50°C for 25 hours. The mixture is then centrifuged and washed with deionized water until the pH of the supernatant reaches 7, obtaining a suspension. The suspension is then subjected to ultrasonic oscillation in an ice bath for 3 hours, followed by vacuum freeze-drying to obtain monolayer MXene nanosheets. In this embodiment, the etchant is prepared by mixing 12M HCl solution with LiF; the volume-to-mass ratio of the HCl solution to LiF is 40 mL:3.2 g; the volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is 45 mL:2 g. The morphology of the monolayer MXene nanosheets is characterized by scanning electron microscopy (SEM), as shown below. Figure 2 As shown.

[0124] S6. Preparation of the composite antibacterial hydrogel: Carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) obtained in step S5 were dissolved in deionized water, stirred and mixed for 25 seconds to obtain a mixture, and then allowed to stand for 4.5 minutes to obtain the ruthenium complex MXene-chitosan composite antibacterial hydrogel, denoted as CMCS-TA-Q / Ru-MXene. In this embodiment, the mass concentration of carboxymethyl chitosan in the mixture system was 3%, the mass concentration of tannic acid in the mixture system was 4%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixture system was 0.5%.

[0125] The ruthenium complex MXene-chitosan composite antibacterial hydrogel was morphologically characterized using scanning electron microscopy (SEM), such as... Figure 3 As shown. By Figure 3 As can be seen, the ruthenium complex MXene chitosan composite antibacterial hydrogel prepared by the present invention exhibits a network cross-linked structure with dense pores inside. Therefore, the ruthenium complex MXene chitosan composite antibacterial hydrogel has good swelling properties.

[0126] Example 2

[0127] A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0128] S1. Preparation of ruthenium precursor: RuCl3-3H2O, 2,2-bipyridine and lithium chloride were dissolved in N,N-dimethylformamide and refluxed at 75°C for 14 h under argon atmosphere. After cooling to room temperature, acetone was added and then the mixture was placed in a freezer at -18°C for 10 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor.

[0129] In this embodiment, the molar volume ratio of ruthenium salt, 2,2-bipyridine, lithium chloride and N,N-dimethylformamide is 6 mmol:13 mmol:18 mmol:8 mL; the volume ratio of acetone to organic solvent added after cooling to room temperature is 4:1.

[0130] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 25 min. Then, the temperature was raised to 55 °C and the reaction was continued with stirring for 6 h. After cooling to room temperature, the ligands were obtained by filtration, washing with ice-cold ethanol, and vacuum drying. In this example, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine was 0.3 mmol: 13 mL.

[0131] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to thionyl chloride, and then heated and stirred under reflux at 75°C for 26 hours. After that, it is dried in a fume hood for 10 hours to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0132] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in anhydrous ethanol, heated under reflux at 75°C and stirred for 14 h, cooled to room temperature, purified by silica gel column chromatography, and the solvent was removed by rotary evaporation to obtain the ruthenium complex; In this example, the molar volume ratio of ligand, ruthenium precursor and anhydrous ethanol was 0.1 mmol:0.1 mmol:25 mL.

[0133] S4. Synthesis of quaternized ruthenium complex: The ruthenium complex and iodomethane were dissolved in anhydrous ethanol, heated to reflux at 75°C and stirred for 14 h, and the solvent was removed by rotary evaporation to obtain the quaternized ruthenium complex, denoted as Q / Ru; In this example, the molar volume ratio of ruthenium complex, iodomethane and anhydrous ethanol was 0.05 mmol:0.1 mmol:25 mL.

[0134] S5. Preparation of quaternary ruthenium complex MXene composite material: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 10 h. Then, the mixture was washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material, denoted as Q / Ru-MXene. In this example, the volume ratio of the quaternary ruthenium complex to the aqueous solution of MXene nanosheets was 0.5:1; the mass concentration of MXene nanosheets in the aqueous solution of MXene nanosheets was 2 mg / mL.

[0135] The preparation method of MXene nanosheets is as follows: Ti3AlC2 ceramic powder with a particle size of 150 mesh is added to the etchant, and the mixture is heated and stirred at 45°C for 30 h. The mixture is then centrifuged and washed with deionized water until the pH of the supernatant is 7 to obtain a suspension. The suspension is then subjected to ultrasonic oscillation in an ice bath for 2.5 h and vacuum freeze-dried to obtain monolayer MXene nanosheets. In this embodiment, the etchant is prepared by mixing 10M HCl solution with LiF. The volume-to-mass ratio of the HCl solution to LiF is 35 mL: 2 g. The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is 40 mL: 1 g.

[0136] S6. Preparation of the composite antibacterial hydrogel: Carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) obtained in step S5 were dissolved in deionized water, stirred and mixed for 20 seconds to obtain a mixture, and then allowed to stand for 4 minutes to obtain the ruthenium complex MXene-chitosan composite antibacterial hydrogel, denoted as CMCS-TA-Q / Ru-MXene. In this embodiment, the mass concentration of carboxymethyl chitosan in the mixture system was 2.5%, the mass concentration of tannic acid in the mixture system was 3.5%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixture system was 0.2%.

[0137] Example 3

[0138] A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0139] S1. Preparation of ruthenium precursor: RuCl3-3H2O, 2,2-bipyridine and lithium chloride were dissolved in N,N-dimethylformamide and refluxed at 85°C for 10 h under argon atmosphere. After cooling to room temperature, acetone was added and then the mixture was frozen at -22°C for 15 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor.

[0140] In this embodiment, the molar volume ratio of ruthenium salt, 2,2-bipyridine, lithium chloride, and N,N-dimethylformamide is 9 mmol:17 mmol:22 mmol:12 mL; the volume ratio of acetone to organic solvent added after cooling to room temperature is 6:1.

[0141] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 35 min. Then, the temperature was raised to 65°C and the reaction was continued with stirring for 4 h. After cooling to room temperature, the ligands were obtained by filtration, washing with ice-cold ethanol, and vacuum drying. In this example, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine was 0.7 mmol: 17 mL.

[0142] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 85°C for 22 h. After that, it is dried in a fume hood for 15 h to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0143] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in anhydrous ethanol, heated under reflux at 85°C and stirred for 10 h, cooled to room temperature, purified by silica gel column chromatography, and the solvent was removed by rotary evaporation to obtain the ruthenium complex; In this example, the molar volume ratio of ligand, ruthenium precursor and anhydrous ethanol was 0.4 mmol:0.4 mmol:35 mL.

[0144] S4. Synthesis of quaternized ruthenium complex: The ruthenium complex and iodomethane were dissolved in anhydrous ethanol, heated to reflux at 85°C and stirred for 10 h, and the solvent was removed by rotary evaporation to obtain the quaternized ruthenium complex, denoted as Q / Ru; In this example, the molar volume ratio of ruthenium complex, iodomethane and anhydrous ethanol was 0.15 mmol:0.3 mmol:35 mL.

[0145] S5. Preparation of quaternary ruthenium complex MXene composite material: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 15 h. Then, the mixture was washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material, denoted as Q / Ru-MXene. In this embodiment, the volume ratio of the quaternary ruthenium complex to the aqueous solution of MXene nanosheets was 2:1; the mass concentration of MXene nanosheets in the aqueous solution of MXene nanosheets was 8 mg / mL.

[0146] The preparation method of MXene nanosheets is as follows: Ti3AlC2 ceramic powder with a particle size of 250 mesh is added to the etchant, and the mixture is heated and stirred at 55°C for 20 h. The mixture is then centrifuged and washed with deionized water until the pH of the supernatant is 7 to obtain a suspension. The suspension is then subjected to ultrasonic oscillation in an ice bath for 3.5 h and vacuum freeze-dried to obtain monolayer MXene nanosheets. In this embodiment, the etchant is prepared by mixing 14M HCl solution with LiF. The volume-to-mass ratio of the HCl solution to LiF is 45 mL: 5 g. The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is 50 mL: 3 g.

[0147] S6. Preparation of the composite antibacterial hydrogel: Carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) obtained in step S5 were dissolved in deionized water, stirred and mixed for 30 seconds to obtain a mixture, and then allowed to stand for 5 minutes to obtain the ruthenium complex MXene-chitosan composite antibacterial hydrogel, denoted as CMCS-TA-Q / Ru-MXene. In this embodiment, the mass concentration of carboxymethyl chitosan in the mixture system was 3.5%, the mass concentration of tannic acid in the mixture system was 4.5%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixture system was 0.8%.

[0148] Example 4

[0149] A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0150] S1. Preparation of ruthenium precursor: RuCl3-3H2O, 2,2-bipyridine and lithium chloride were dissolved in N,N-dimethylformamide and refluxed at 78°C for 13 h under argon atmosphere. After cooling to room temperature, acetone was added and then the mixture was frozen at -19°C for 11 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor.

[0151] In this embodiment, the molar volume ratio of ruthenium salt, 2,2-bipyridine, lithium chloride and N,N-dimethylformamide is 7 mmol:14 mmol:19 mmol:9 mL; the volume ratio of acetone to organic solvent added after cooling to room temperature is 4.5:1.

[0152] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 27 min. Then, the temperature was raised to 58 °C and the reaction was continued with stirring for 5.5 h. After cooling to room temperature, the ligands were obtained by filtration, washing with ice-cold ethanol, and vacuum drying. In this example, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine was 0.4 mmol: 14 mL.

[0153] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 78°C for 25 h. After that, it is dried in a fume hood for 11 h to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0154] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in anhydrous ethanol, heated under reflux at 78°C and stirred for 13 h, cooled to room temperature, purified by silica gel column chromatography, and the solvent was removed by rotary evaporation to obtain the ruthenium complex; In this example, the molar volume ratio of ligand, ruthenium precursor and anhydrous ethanol was 0.2 mmol:0.2 mmol:28 mL.

[0155] S4. Synthesis of quaternized ruthenium complex: The ruthenium complex and iodomethane were dissolved in anhydrous ethanol, heated to reflux at 78°C and stirred for 13 h, and the solvent was removed by rotary evaporation to obtain the quaternized ruthenium complex, denoted as Q / Ru; In this example, the molar volume ratio of ruthenium complex, iodomethane and anhydrous ethanol was 0.08 mmol:0.15 mmol:28 mL.

[0156] S5. Preparation of quaternary ruthenium complex MXene composite material: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 11 h. Then, the mixture was washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material, denoted as Q / Ru-MXene. In this embodiment, the volume ratio of the quaternary ruthenium complex to the aqueous solution of MXene nanosheets was 1.5:2; the mass concentration of MXene nanosheets in the aqueous solution of MXene nanosheets was 3 mg / mL.

[0157] The preparation method of MXene nanosheets is as follows: Ti3AlC2 ceramic powder with a particle size of 180 mesh is added to the etchant, and the mixture is heated and stirred at 48°C for 28 hours. The mixture is then centrifuged and washed with deionized water until the pH of the supernatant is 7 to obtain a suspension. The suspension is then subjected to ultrasonic oscillation in an ice bath for 2.7 hours and freeze-dried under vacuum to obtain monolayer MXene nanosheets. In this embodiment, the etchant is prepared by mixing 11M HCl solution with LiF. The volume-to-mass ratio of the HCl solution to LiF is 38 mL:3 g. The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is 42 mL:1.5 g.

[0158] S6. Preparation of the composite antibacterial hydrogel: Carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) obtained in step S5 were dissolved in deionized water, stirred and mixed for 23 seconds to obtain a mixture, and then allowed to stand for 4.3 minutes to obtain the ruthenium complex MXene-chitosan composite antibacterial hydrogel, denoted as CMCS-TA-Q / Ru-MXene. In this embodiment, the mass concentration of carboxymethyl chitosan in the mixture system was 2.8%, the mass concentration of tannic acid in the mixture system was 3.7%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixture system was 0.3%.

[0159] Example 5

[0160] A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0161] S1. Preparation of ruthenium precursor: RuCl3-3H2O, 2,2-bipyridine and lithium chloride were dissolved in N,N-dimethylformamide and refluxed at 82°C for 11 h under argon atmosphere. After cooling to room temperature, acetone was added and then the mixture was placed in a freezer at -21°C for 14 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor.

[0162] In this embodiment, the molar volume ratio of ruthenium salt, 2,2-bipyridine, lithium chloride and N,N-dimethylformamide is 8 mmol:16 mmol:21 mmol:11 mL; the volume ratio of acetone to organic solvent added after cooling to room temperature is 5.5:1.

[0163] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 32 min. Then, the temperature was raised to 63 °C and the reaction was continued with stirring for 4.5 h. After cooling to room temperature, the ligands were obtained by filtration, washing with ice-cold ethanol, and vacuum drying. In this example, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine was 0.6 mmol: 16 mL.

[0164] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 83°C for 23 hours. After that, it is dried in a fume hood for 14 hours to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0165] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in anhydrous ethanol, heated under reflux at 83°C and stirred for 11 h, cooled to room temperature, purified by silica gel column chromatography, and the solvent was removed by rotary evaporation to obtain the ruthenium complex; In this example, the molar volume ratio of ligand, ruthenium precursor and anhydrous ethanol was 0.3 mmol:0.4 mmol:32 mL.

[0166] S4. Synthesis of quaternized ruthenium complex: The ruthenium complex and iodomethane were dissolved in anhydrous ethanol, and the mixture was heated under reflux at 83°C and stirred for 11 h. The solvent was then removed by rotary evaporation to obtain the quaternized ruthenium complex, denoted as Q / Ru. In this example, the molar volume ratio of the ruthenium complex, iodomethane, and anhydrous ethanol was 0.12 mmol:0.25 mmol:33 mL.

[0167] S5. Preparation of quaternary ruthenium complex MXene composite material: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 14 h. Then, the mixture was washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material, denoted as Q / Ru-MXene. In this example, the volume ratio of the quaternary ruthenium complex to the aqueous solution of MXene nanosheets was 2:1.6; the mass concentration of MXene nanosheets in the aqueous solution of MXene nanosheets was 7 mg / mL.

[0168] The preparation method of MXene nanosheets is as follows: Ti3AlC2 ceramic powder with a particle size of 220 mesh is added to the etchant, and the mixture is heated and stirred at 52°C for 22 hours. The mixture is then centrifuged and washed with deionized water until the pH of the supernatant is 7 to obtain a suspension. The suspension is then subjected to ultrasonic oscillation in an ice bath for 3.3 hours and freeze-dried under vacuum to obtain monolayer MXene nanosheets. In this embodiment, the etchant is prepared by mixing 13M HCl solution with LiF. The volume-to-mass ratio of the HCl solution to LiF is 43 mL:4 g. The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is 48 mL:2.5 g.

[0169] S6. Preparation of the composite antibacterial hydrogel: Carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) obtained in step S5 were dissolved in deionized water, stirred and mixed for 28 seconds to obtain a mixture, and then allowed to stand for 4.8 minutes to obtain the ruthenium complex MXene-chitosan composite antibacterial hydrogel, denoted as CMCS-TA-Q / Ru-MXene. In this embodiment, the mass concentration of carboxymethyl chitosan in the mixture system was 3.3%, the mass concentration of tannic acid in the mixture system was 4.3%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixture system was 0.7%.

[0170] Example 6

[0171] A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel includes the following steps:

[0172] S1. Preparation of ruthenium precursor: RuCl3-3H2O, 2,2-bipyridine and lithium chloride were dissolved in N,N-dimethylformamide and refluxed at 81°C for 12.5 h under argon atmosphere. After cooling to room temperature, acetone was added and then the mixture was frozen at -20°C for 13 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor.

[0173] In this embodiment, the molar volume ratio of ruthenium salt, 2,2-bipyridine, lithium chloride and N,N-dimethylformamide is 7 mmol:15 mmol:21 mmol:10 mL; the volume ratio of acetone to organic solvent added after cooling to room temperature is 4.8:1.

[0174] S2. Preparation of ligands: 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 31 min. Then, the temperature was raised to 62°C and the reaction was continued with stirring for 5 h. After cooling to room temperature, the ligands were obtained by filtration, washing with ice-cold ethanol, and vacuum drying. In this example, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine was 0.6 mmol: 15 mL.

[0175] The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 79°C for 24 h. After that, it is dried in a fume hood for 13.5 h to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

[0176] S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in anhydrous ethanol, heated under reflux at 81°C and stirred for 12 h, cooled to room temperature, purified by silica gel column chromatography, and the solvent was removed by rotary evaporation to obtain the ruthenium complex; In this example, the molar volume ratio of ligand, ruthenium precursor and anhydrous ethanol was 0.3 mmol:0.2 mmol:31 mL.

[0177] S4. Synthesis of quaternized ruthenium complex: The ruthenium complex and iodomethane were dissolved in anhydrous ethanol and heated under reflux at 75℃~85℃ with stirring for 13h. The solvent was then removed by rotary evaporation to obtain the quaternized ruthenium complex, denoted as Q / Ru. In this example, the molar volume ratio of the ruthenium complex, iodomethane and anhydrous ethanol was 0.09mmol:0.18mmol:29mL.

[0178] S5. Preparation of quaternary ruthenium complex MXene composite material: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 13 h. Then, the mixture was washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material, denoted as Q / Ru-MXene. In this example, the volume ratio of the quaternary ruthenium complex to the aqueous solution of MXene nanosheets was 1.8:1.5; the mass concentration of MXene nanosheets in the aqueous solution was 6 mg / mL.

[0179] The preparation method of MXene nanosheets is as follows: Ti3AlC2 ceramic powder with a particle size of 210 mesh is added to the etchant, and the mixture is heated and stirred at 49°C for 25 h. The mixture is then centrifuged and washed with deionized water until the pH of the supernatant is 7 to obtain a suspension. The suspension is then subjected to ultrasonic oscillation in an ice bath for 2.9 h and freeze-dried under vacuum to obtain monolayer MXene nanosheets. In this embodiment, the etchant is prepared by mixing 12M HCl solution with LiF. The volume-to-mass ratio of the HCl solution to LiF is 39 mL:4 g. The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is 46 mL:2 g.

[0180] S6. Preparation of the composite antibacterial hydrogel: Carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) obtained in step S5 were dissolved in deionized water, stirred and mixed for 27 seconds to obtain a mixture, and then allowed to stand for 4.6 minutes to obtain the ruthenium complex MXene-chitosan composite antibacterial hydrogel, denoted as CMCS-TA-Q / Ru-MXene. In this embodiment, the mass concentration of carboxymethyl chitosan in the mixture system was 2.9%, the mass concentration of tannic acid in the mixture system was 3.8%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixture system was 0.5%.

[0181] Example 7

[0182] Application of a ruthenium complex MXene chitosan composite antibacterial hydrogel: The ruthenium complex MXene chitosan composite antibacterial hydrogel prepared by any one of the preparation methods of Examples 1 to 6 is used in the preparation of medical antibacterial drugs and wound repair materials.

[0183] Comparative Example 1

[0184] A method for preparing a ruthenium complex chitosan hydrogel is disclosed. The difference between this comparative example and Example 1 is that the raw materials for preparing the hydrogel in step S6 are: carboxymethyl chitosan (CMCS), tannic acid (TA), and the quaternized ruthenium complex (Q / Ru) obtained in step S4. That is, in step S6, the quaternized ruthenium complex (Q / Ru) is used instead of the quaternized ruthenium complex MXene composite material (Q / Ru-MXene). The ruthenium complex chitosan hydrogel prepared in this comparative example is denoted as CMCS-TA-Q / Ru. The remaining preparation methods of this comparative example are the same as in Example 1.

[0185] Comparative Example 2

[0186] A method for preparing a hydrogel is disclosed. This comparative example differs from Example 1 in that the raw materials for preparing the hydrogel in step S6 are carboxymethyl chitosan (CMCS) and tannic acid (TA). That is, in step S6, the quaternary ruthenium complex MXene composite material (Q / Ru-MXene) is omitted. The hydrogel prepared in this comparative example is denoted as CMCS-TA. The remaining preparation methods of this comparative example are the same as in Example 1.

[0187] Comparative Example 3

[0188] A method for preparing a hydrogel is disclosed. This comparative example differs from Example 1 in that the raw materials for preparing the hydrogel in step S6 are carboxymethyl chitosan (CMCS), tannic acid (TA), and an aqueous solution of MXene nanosheets. Specifically, an aqueous solution of MXene nanosheets (MXene nanosheet mass concentration of 5 mg / mL) is used instead of the quaternary ruthenium complex MXene composite material (Q / Ru-MXene). The hydrogel prepared in this comparative example is denoted as CMCS-TA-MXene. The remaining preparation methods of this comparative example are the same as in Example 1.

[0189] Performance analysis and testing

[0190] (I) Detection of pH and near-infrared laser-responsive release of hydrogels

[0191] The ruthenium complex chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 and the ruthenium complex chitosan hydrogel (CMCS-TA-Q / Ru) prepared in Comparative Example 1 were irradiated with a 1.5W near-infrared laser for 30 min in an acidic environment with a pH of 6.0. The cumulative release rate of CMCS-TA-Q / Ru-MXene and CMCS-TA-Q / Ru within 30 min was measured, and the results are as follows. Figure 4 As shown.

[0192] Depend on Figure 4 As can be seen, under acidic conditions of pH 6.0 and irradiation with a 1.5W near-infrared laser, the CMCS-TA-Q / Ru-MXene hydrogel prepared in Example 1 exhibited a cumulative release rate of up to 90% within 30 minutes, while the CMCS-TA-Q / Ru hydrogel prepared in Comparative Example 1 showed a cumulative release rate of only 30%. This demonstrates that the ruthenium complex MXene-chitosan composite antibacterial hydrogel prepared in this invention possesses excellent drug release performance. Furthermore, it was also confirmed that the synergistic effect of the acidic environment and photothermal effect can effectively promote the dissociation of the hydrogel network, thereby enhancing drug release.

[0193] In addition, the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was subjected to near-infrared laser irradiation at different power densities for 30 minutes in an acidic environment at pH 6.0, and the cumulative release rate of CMCS-TA-Q / Ru-MXene within 30 minutes was measured under both irradiation conditions and in the absence of light. The test results are as follows. Figure 5 As shown.

[0194] Depend on Figure 5 As can be seen, the cumulative release rate of CMCS-TA-Q / Ru-MXene hydrogel is only 20% under no light irradiation, 55% under 1.0W laser irradiation, and as high as 90% under 1.5W laser irradiation. This indicates a clear dose-dependent relationship between the photothermal effect and drug release behavior; the higher the laser power density, the higher the cumulative drug release rate. Therefore, laser power density is a key parameter for controlling the release rate.

[0195] In addition, the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was irradiated with a 1.0W near-infrared laser for 30 minutes under different pH conditions (pH 4.5, 6.0, 7.4, and 9.0). The cumulative release rate of CMCS-TA-Q / Ru-MXene within 30 minutes was measured. The test results are as follows: Figure 6 As shown.

[0196] In addition, the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was tested under different pH conditions (pH 4.5, 6.0, 7.4, and 9.0) without near-infrared laser irradiation. The cumulative release rate of CMCS-TA-Q / Ru-MXene within 30 minutes was measured. The test results are as follows. Figure 7 As shown.

[0197] from Figure 6 and Figure 7 It can be seen that the release of the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in this invention increases with decreasing pH of the release medium, and exhibits significant pH responsiveness in both the presence and absence of near-infrared light irradiation. This is because, under acidic conditions, the amino groups (-NH2) in carboxymethyl chitosan (CMCS) are reacted with excess H+. + Substitution, transforming into protonated amino NH3 +This causes some disruption to the stability of the hydrogel's network structure. Increased temperature after near-infrared laser irradiation accelerates the breakdown of the hydrogel network, leading to the rapid release of CMCS-TA-Q / Ru-MXene, indicating that the hydrogel exhibits certain pH-responsive characteristics.

[0198] In addition, the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was subjected to different pH environments (pH 4.5 and 7.4) for 15 min of release followed by 1.0W near-infrared laser irradiation for 15 min. The cumulative release rate was measured, and the results are as follows: Figure 8 As shown.

[0199] Depend on Figure 8 As can be seen, when the ambient pH decreased from physiological conditions (7.4) to acidic conditions (4.5), the release rate of the CMCS-TA-Q / Ru-MXene hydrogel prepared in this invention significantly increased from 7% to 35% within 15 minutes, confirming the sensitivity of the CMCS-TA-Q / Ru-MXene prepared in this invention to pH changes. After applying 1.0W near-infrared laser irradiation at 15 minutes, the release rate under pH 4.5 conditions increased sharply to 80% within 15 minutes, while the release rate under the same light conditions at pH 7.4 only showed a slight increase (about 12%). These results not only verify the ability of near-infrared photothermal effects to regulate drug release, but also reveal the synergistic effect of the dual response mechanism of pH and photothermal: the acidic environment weakens the hydrogel network structure through protonation, while the local thermal effect generated by near-infrared irradiation further accelerates network dissociation, thereby achieving precise and controllable drug release. This intelligent response characteristic provides an important reference for the development of environmentally sensitive drug delivery systems.

[0200] (II) Testing the injectability and self-healing properties of hydrogels

[0201] The apparent viscosity and shear rate of the four hydrogels prepared in Example 1 (CMCS-TA-Q / Ru-MXene), Comparative Example 1 (CMCS-TA-Q / Ru), Comparative Example 2 (CMCS-TA), and Comparative Example 3 (CMCS-TA-MXene) were measured using a rheometer. The test results are as follows: Figure 9 As shown.

[0202] Depend on Figure 9 It can be seen that all four hydrogels exhibit typical shear-thinning behavior: as the shear rate increases from 0.1 s⁻¹... -1 Increase to 100s -1The apparent viscosity decreased significantly by 2-3 orders of magnitude. In particular, the CMCS-TA-Q / Ru-MXene prepared in Example 1 of this invention exhibited even better shear-thinning properties. The excellent shear-thinning properties of the CMCS-TA-Q / Ru-MXene prepared in this invention stem from the temporary dissociation of the dynamic cross-linked network under shear force, causing the hydrogel to exhibit liquid behavior during injection, allowing it to pass smoothly through a 22G needle and accurately write the letter "GDUT," as shown in the example. Figure 10 As shown, it quickly returns to a gel state after injection, thus adhering well to the wound.

[0203] In addition, the self-healing properties of the CMCS-TA-Q / Ru-MXene prepared in Example 1 and the CMCS-TA-Q / Ru prepared in Comparative Example 1 were tested. Macroscopic self-healing experiments confirmed the self-healing properties of the CMCS-TA-Q / Ru-MXene hydrogel and the CMCS-TA-Q / Ru hydrogel of the present invention. For the self-healing process, please refer to [link to relevant documentation]. Figure 11 . Figure 11 In the image, the black hydrogel is CMCS-TA-Q / Ru-MXene, and the translucent hydrogel is CMCS-TA-Q / Ru. From... Figure 11 As can be seen, when CMCS-TA-Q / Ru-MXene hydrogels and CMCS-TA-Q / Ru hydrogels are cut, complete healing and restoration of original mechanical strength can be achieved within 1 minute of contact between the cut surfaces. This self-healing ability is mainly attributed to the reversible properties of dynamic ionic and hydrogen bonds in the network structure: at the damaged site, these dynamic bonds can rapidly recombine, rebuilding the three-dimensional cross-linked network. This self-repair process can be completed spontaneously without external stimulation, and the repaired hydrogel retains certain mechanical properties, providing an ideal solution for long-term wound care.

[0204] (III) Adhesion performance testing of hydrogels

[0205] The ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was used to adhere to substrates such as plastic, polytetrafluoroethylene, wood, rubber, glass, and metal. The adhesion ability of the hydrogel was tested by apparent adhesion experiments. Figure 12 As shown. By Figure 12 As can be seen, the hydrogel prepared by this invention has a certain degree of adhesion to substrates such as plastics, polytetrafluoroethylene, wood, rubber, glass, and metals. The adhesive properties of the hydrogel are an important functional characteristic as a wound dressing. This property allows it to adhere firmly to the wound surface, providing an ideal moist healing environment for the wound, while effectively blocking the invasion of external bacteria.

[0206] In addition, the ruthenium complex chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1, the ruthenium complex chitosan hydrogel (CMCS-TA-Q / Ru) prepared in Comparative Example 1, the hydrogel (CMCS-TA) prepared in Comparative Example 2, and the hydrogel (CMCS-TA-MXene) prepared in Comparative Example 3 were respectively adhered to pigskin, and the force exerted by the hydrogel on the pigskin at different times was tested. The test results are as follows. Figure 13 As shown in the figure. The adhesion strength of the hydrogel to pigskin was tested, and the test results are as follows. Figure 14 As shown. By Figure 13 and Figure 14 As can be seen, the CMCS-TA-Q / Ru-MXene of Example 1 and the CMCS-TA-MXene of Comparative Example 3 exhibit significantly improved adhesive properties due to the introduction of MXene and Q / Ru. This enhancement effect stems from the synergistic effect of multiple components: the polyphenol groups in the hydrogel form chemical bonds with the amino / thiol groups of skin tissue, while the addition of MXene and Q / Ru further strengthens the interfacial interactions by increasing the number of hydroxyl and amino groups in the system. This multi-physical-chemical cross-linking network not only improves the cohesive strength of the hydrogel but also enables it to adhere firmly to irregular wound surfaces, providing an ideal moist healing microenvironment for the wound, while effectively blocking the invasion of external pathogenic microorganisms, thereby promoting the tissue repair process.

[0207] (iv) Photothermal Properties Testing of Hydrogels

[0208] The ruthenium complex chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1, the ruthenium complex chitosan hydrogel (CMCS-TA-Q / Ru) prepared in Comparative Example 1, the hydrogel (CMCS-TA) prepared in Comparative Example 2, and the hydrogel (CMCS-TA-MXene) prepared in Comparative Example 3 were irradiated with a near-infrared laser (1.0W) for 5 minutes, and the temperature change detection was turned off for 5 minutes. The test results are as follows. Figure 15 As shown. By Figure 15 As can be seen, after 5 min of near-infrared irradiation (1.0 W), the temperature of CMCS-TA-MXene and CMCS-TA-MXene / Ru hydrogels increased by about 25 °C, while the temperature of CMCS-TA and CMCS-TA-Q / Ru hydrogels without MXene only increased by about 3 °C. The results indicate that the introduction of MXene has a significant impact on the near-infrared responsiveness of the hydrogel, while the quaternary ruthenium complex (Q / Ru) has little effect on the photothermal effect of the hydrogel.

[0209] In addition, the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was irradiated for 5 minutes with different near-infrared laser power densities (0.5, 1.0, 1.5W), and the temperature change detection was turned off for 5 minutes. The test results are as follows. Figure 16 As shown. By Figure 16 As can be seen, after irradiation with different near-infrared laser power densities (0.5, 1.0, and 1.5 W) for 5 min, the corresponding temperature rise of CMCS-TA-Q / Ru-MXene increased significantly, reaching 20℃, 25℃, and 30℃, respectively. The results indicate that the CMCS-TA-Q / Ru-MXene hydrogel possesses significant photothermal conversion capability, and the photothermal effect is enhanced with increasing near-infrared laser power density.

[0210] In addition, the temperature change of the ruthenium complex MXene-chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1 was detected under three on / off cycles of near-infrared laser (1.0W). The test results are as follows. Figure 17 As shown. By Figure 17 As can be seen, after three laser switching cycle tests, the temperature curve and peak temperature of the CMCS-TA-Q / Ru-MXene hydrogel in Example 1 remained stable, indicating that it has excellent photothermal stability and reusability.

[0211] The above test results on the photothermal properties of the hydrogel confirm that the introduction of MXene enables the hydrogel to achieve efficient and stable photothermal conversion capabilities.

[0212] (v) Testing of the antioxidant properties of hydrogels

[0213] Reactive oxygen species (ROS) are a byproduct of cellular metabolism. Low levels of ROS are beneficial for killing bacteria on the wound surface, but excessive ROS can trigger inflammation, thus hindering wound healing and tissue regeneration. First, the antioxidant properties of the hydrogel were evaluated through scavenging experiments on DPPH and hydroxyl radicals. DPPH radicals are stable nitrogen-centered free radicals and are an important indicator of a sample's antioxidant capacity. DPPH radicals have a single electron, and their alcoholic solution is purple with strong absorption at 515 nm. When antioxidants are present, DPPH radicals are scavenged, and the solution color lightens. The decrease in absorbance at 515 nm reflects the sample's ability to scavenge DPPH radicals. Hydroxyl radicals act on biomolecules such as proteins, nucleic acids, and lipids, easily causing damage to cell structure and function. The Fenton reaction is commonly used to determine the effect of hydrogels on hydroxyl radicals.

[0214] The ruthenium complex chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1, the ruthenium complex chitosan hydrogel (CMCS-TA-Q / Ru) prepared in Comparative Example 1, the hydrogel (CMCS-TA) prepared in Comparative Example 2, and the hydrogel (CMCS-TA-MXene) prepared in Comparative Example 3 were soaked in PBS solution (phosphate buffered saline) for 10 min to obtain hydrogel extract samples. Vitamin C (VC) samples were also prepared by dissolving VC in PBS solution. In all the above samples, the concentration of both hydrogel and VC in the solution system was 10 mg / mL. The scavenging rates of DPPH free radicals and hydroxyl free radicals in the above samples were tested, and the test results are as follows: Figure 18 and Figure 19 As shown. By Figure 18 , 19 It is evident that all four hydrogels exhibit strong scavenging efficiency against DPPH and hydroxyl radicals, even surpassing that of vitamin C (VC). This is because the phenolic hydroxyl group derived from tannic acid (TA) can provide a hydrogen atom or electron to react with free radicals without generating new free radicals.

[0215] In addition, WI38 cells were treated with a ruthenium complex chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1, a ruthenium complex chitosan hydrogel (CMCS-TA-Q / Ru) prepared in Comparative Example 1, a hydrogel (CMCS-TA) prepared in Comparative Example 2, and a hydrogel (CMCS-TA-MXene) prepared in Comparative Example 3, and fluorescence images during DCFH-DA staining were detected.

[0216] The intracellular ROS levels of WI38 cells stimulated with H2O2 were detected using the DCFH-DA staining method under hydrogel-containing and hydrogel-free extraction media. DCFH-DA can penetrate the cell membrane, is deacetylated by intracellular esterases, and then oxidized to DCF by ROS, exhibiting green fluorescence under an inverted fluorescence microscope. The detection method involved detecting the fluorescence images of WI38 cells after treatment with PBS solution without H2O2 (blank control), 1 mM H2O2, 1 mM H2O2 + CMCS-TA hydrogel, 1 mM H2O2 + CMCS-TA-Q / Ru hydrogel, 1 mM H2O2 + CMCS-TA-MXene hydrogel, and 1 mM H2O2 + CMCS-TA-Q / Ru-MXene hydrogel during DCFH-DA staining. (See attached image). Figure 20 As shown. By Figure 20As can be seen, WI38 cells exhibited strong green light after H2O2 stimulation, indicating the production of a large amount of ROS. However, after culturing with the hydrogel extract, the intracellular ROS level was significantly reduced, almost identical to that of the control group. These results suggest that this type of hydrogel can effectively remove intracellular ROS, thereby reducing oxidative stress damage to damaged tissues and promoting wound healing.

[0217] (vi) Testing of the antibacterial properties of hydrogels

[0218] The antibacterial properties of hydrogels were systematically evaluated using the agar diffusion method.

[0219] The ruthenium complex chitosan composite antibacterial hydrogels prepared in Example 1 (CMCS-TA-Q / Ru-MXene), Comparative Example 1 (CMCS-TA-Q / Ru), Comparative Example 2 (CMCS-TA), and Comparative Example 3 (CMCS-TA-MXene) were subjected to different levels of inhibition on Escherichia coli colony growth under conditions of no light and 1.0W near-infrared laser irradiation for 5 minutes. Figure 21 As shown in the figure. The diameters of the inhibition zones formed near the four types of hydrogels after 12 hours of incubation were also measured, and the results are shown in the figure. Figure 22 As shown.

[0220] Depend on Figure 21 and 22 As can be seen, no obvious inhibition zone was formed in the CMCS-TA-MXene hydrogel experimental group, indicating that MXene mainly exerts its bactericidal effect through surface contact, with limited inhibition of the growth of surrounding colonies. Both the CMCS-TA-Q / Ru and CMCS-TA-Q / Ru-MXene hydrogel experimental groups showed obvious inhibition zones, indicating that the quaternary ruthenium complex can effectively release and inhibit the growth of surrounding bacteria. After near-infrared light treatment, the antibacterial effect of the CMCS-TA-Q / Ru-MXene experimental group was significantly enhanced, confirming the synergistic antibacterial effect of photothermal and photodynamic therapy. These results indicate that the introduction of the quaternary ruthenium complex endows the hydrogel with diffusible antibacterial activity, and near-infrared light irradiation can further promote drug release through the photothermal effect, enhancing the antibacterial effect.

[0221] Furthermore, the effect of adjusting the loading of quaternary ruthenium complex (Q / Ru) in the quaternary ruthenium complex MXene composite (Q / Ru-MXene) on its antibacterial effect was investigated. Four hydrogels with different Q / Ru loadings were prepared: CMCS-TA-Q / Ru1-MXene, CMCS-TA-Q / Ru2-MXene, CMCS-TA-Q / Ru4-MXene, and CMCS-TA-Q / Ru8-MXene. The mass percentages of Q / Ru in these four hydrogels were 1%, 2%, 4%, and 8%, respectively. The inhibition of *E. coli* colony growth by these four hydrogels under light-free conditions and under 1.0W near-infrared laser irradiation for 5 min was measured. Figure 23 As shown in the figure. The diameters of the inhibition zones formed near the four types of hydrogels after 12 hours of incubation were also measured, and the results are shown in the figure. Figure 24 As shown. By Figure 23 and 24 It is evident that the diameter of the inhibition zone exhibits a significant positive correlation with the Q / Ru loading. As the Q / Ru loading increases, the corresponding inhibition zone diameter also increases, indicating that the antibacterial effect of the sample is dose-dependent. With the increase of Q / Ru loading, the concentration of active ingredients released from the hydrogel per unit time increases accordingly, thereby inhibiting bacterial growth more efficiently through a synergistic mechanism of chemo-photodynamic-photothermal action.

[0222] (vii) In vitro coagulation and hemolysis properties testing of hydrogels

[0223] The in vitro coagulation and hemolysis properties of the ruthenium complex chitosan composite antibacterial hydrogel (CMCS-TA-Q / Ru-MXene) prepared in Example 1, the ruthenium complex chitosan hydrogel (CMCS-TA-Q / Ru) prepared in Comparative Example 1, the hydrogel (CMCS-TA) prepared in Comparative Example 2, and the hydrogel (CMCS-TA-MXene) prepared in Comparative Example 3 were evaluated, and a blank control was performed.

[0224] The in vitro hemostatic properties and blood compatibility of four hydrogels were evaluated by measuring the coagulation index (BCI) and hemolysis rate. The coagulation index (BCI) reflects the proportion of free red blood cells that did not participate in clotting within a fixed clotting time; a lower BCI value indicates better hemostatic ability of the surface sample. Figure 25 As can be seen, the BCI values ​​of the four hydrogels are all below 30%, and the BCI value of CMCS-TA-Q / Ru-MXene is the lowest, at only 15%. This indicates that the ruthenium complex MXene chitosan composite antibacterial hydrogel prepared in this invention has a significant procoagulant effect, which is mainly attributed to the specific binding effect of tannic acid (TA) with blood proteins.

[0225] In addition, regarding blood compatibility, the hemolysis rate test results are as follows: Figure 26 As shown. By Figure 26 As can be seen, the hemolysis rates of the four hydrogels were all below 3.5%, which is below the safety threshold of 5%. This result confirms that the hydrogels prepared in this invention do not cause significant red blood cell rupture or hemoglobin release, and possess good blood compatibility. Furthermore, the hemolysis test results are as follows... Figure 27 As shown in the figures, these data demonstrate that the hydrogel prepared in this invention possesses both excellent hemostatic properties and biocompatibility, making it valuable for applications in the field of trauma treatment.

[0226] (viii) Biocompatibility testing of hydrogels

[0227] Biocompatibility is a key indicator for the application of hydrogel wound dressings. In this study, human embryonic lung fibroblasts WI38 were used as an in vitro model to systematically evaluate the biocompatibility of four hydrogels: a ruthenium complex chitosan composite antibacterial hydrogel prepared in Example 1 (CMCS-TA-Q / Ru-MXene), a ruthenium complex chitosan hydrogel prepared in Comparative Example 1 (CMCS-TA-Q / Ru), a hydrogel prepared in Comparative Example 2 (CMCS-TA), and a hydrogel prepared in Comparative Example 3 (CMCS-TA-MXene). A blank control group was also set up.

[0228] Sample preparation: CMCS-TA-Q / Ru-MXene (Example 1), CMCS-TA-Q / Ru (Comparative Example 1), CMCS-TA (Comparative Example 2), and CMCS-TA-MXene (Comparative Example 3) were prepared by soaking in DMEM high-glucose medium for 10 min. The blank sample was DMEM high-glucose medium. Cell viability was detected using the CCK-8 assay. This method is based on the principle that WST-8 reagent is reduced to water-soluble formazan by mitochondrial dehydrogenases in living cells. Cell viability is quantified by measuring absorbance at 450 nm. The detection results are as follows: Figure 28 As shown. By Figure 28 As can be seen, under both light and dark conditions, after 24 hours of treatment with the four hydrogel leachates, the survival rate of WI38 cells remained above 80%, indicating that the hydrogel prepared by this invention has good cell compatibility.

[0229] In addition, the four hydrogel extracts and the blank control group were subjected to fluorescence staining detection of live / dead cells, and the results are as follows: Figure 29 As shown. By Figure 29As can be seen, high density of bright green fluorescently labeled live cells (acrididine orange staining) was observed in all experimental groups, while the number of red fluorescently labeled dead cells (propidium iodide staining) was extremely small. This result corroborates the cell viability data obtained by the CCK-8 assay, confirming that all four hydrogels possess excellent biocompatibility. This demonstrates that the ruthenium complex MXene chitosan composite antibacterial hydrogel prepared in this invention maintains excellent biocompatibility despite the introduction of antibacterial components, meeting the application requirements for wound dressings.

[0230] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a ruthenium complex MXene chitosan composite antibacterial hydrogel, characterized in that, Includes the following steps: S1. Preparation of ruthenium precursor: Ruthenium salt, 2,2-bipyridine and lithium chloride were dissolved in an organic solvent and heated under reflux in an inert atmosphere. After filtration and washing, the ruthenium precursor was obtained. S2. Preparation of ligands: 3-Dimethylaminopropylamine was added to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an inert atmosphere. Then the temperature was raised and the stirring was continued. The ligands were obtained after filtration, washing and drying. S3. Preparation of ruthenium complex: The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 are dissolved in a solvent, heated under reflux and stirred to react, cooled, separated and purified, and the solvent is removed to obtain the ruthenium complex. S4. Synthesis of quaternary ruthenium complex: The ruthenium complex was dissolved in iodomethane in a solvent, heated under reflux and stirred to react, and then the solvent was removed to obtain the quaternary ruthenium complex; S5. Preparation of MXene quaternary ruthenium complex: The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets, and the mixture was stirred and reacted at room temperature in the dark under an inert atmosphere. After washing and drying, the MXene quaternary ruthenium complex was obtained. S6. Preparation of composite antibacterial hydrogel: Carboxymethyl chitosan, tannic acid, and the quaternary ammonium ruthenium complex MXene composite material obtained in step S5 are dissolved in water, stirred and mixed to obtain a mixture, and allowed to stand to obtain the ruthenium complex MXene chitosan composite antibacterial hydrogel.

2. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S1, the molar volume ratio of the ruthenium salt, 2,2-bipyridine, lithium chloride, and organic solvent is (6–9) mmol:(13–17) mmol:(18–22) mmol:(8–12) mL; and / or The ruthenium salt is RuCl3-3H2O; and / or, the organic solvent is N,N-dimethylformamide; and / or Ruthenium salt, 2,2-bipyridine, and lithium chloride were dissolved in an organic solvent and refluxed at 75°C–85°C for 10–14 h under an argon atmosphere. After cooling to room temperature, acetone was added, and the mixture was then frozen at -18°C–22°C for 10–15 h. After filtration, the mixture was washed with ice water and then with acetone to obtain the ruthenium precursor. The volume ratio of acetone added after cooling to room temperature to the organic solvent was (4–6):

1.

3. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S2, the molar volume ratio of 2,2-bipyridine-4,4-dicarboxylic acid chloride to 3-dimethylaminopropylamine is (0.3–0.7) mmol:(13–17) mL; and / or 3-Dimethylaminopropylamine was added dropwise to 2,2-bipyridine-4,4-dicarboxylic acid chloride, and the mixture was stirred in an ice bath under an argon atmosphere for 25-35 minutes. The temperature was then raised to 55-65°C, and the reaction was continued with stirring for 4-6 hours. After cooling to room temperature, the ligand was obtained by filtration, washing with ice-cold ethanol, and vacuum drying; and / or The synthesis method of 2,2-bipyridine-4,4-dicarboxylic acid is as follows: 2,2-bipyridine-4,4-dicarboxylic acid is added to sulfoxide, and then heated and stirred under reflux at 75℃~85℃ for 22h~26h. Then, it is dried in a fume hood for 10h~15h to obtain 2,2-bipyridine-4,4-dicarboxylic acid.

4. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S3, the molar volume ratio of the ligand, ruthenium precursor, and solvent is (0.1–0.4) mmol:(0.1–0.4) mmol:(25–35) mL; and / or The solvent is anhydrous ethanol; and / or The ligand obtained in step S2 and the ruthenium precursor obtained in step S1 were dissolved in a solvent and heated under reflux at 75℃~85℃ for 10h~14h. After cooling to room temperature, the mixture was purified by silica gel column chromatography and the solvent was removed by rotary evaporation to obtain the ruthenium complex.

5. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S4, the molar volume ratio of the ruthenium complex, iodomethane, and solvent is (0.05–0.15) mmol:(0.1–0.3) mmol:(25–35) mL; and / or The solvent is anhydrous ethanol; and / or The ruthenium complex was dissolved in iodomethane and heated under reflux at 75°C to 85°C for 10 to 14 hours with stirring. The solvent was then removed by rotary evaporation to obtain the quaternized ruthenium complex.

6. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S5, the MXene nanosheets are prepared by: adding Ti3AlC2 ceramic powder to the etchant, heating and stirring at 45℃~55℃ for 20h~30h, washing with deionized water by centrifugation until the pH of the supernatant is 7 to obtain a suspension, then subjecting the suspension to ultrasonic oscillation in an ice bath for 2.5h~3.5h, followed by vacuum freeze-drying to obtain monolayer MXene nanosheets; and / or The etchant is prepared by mixing 10M-14M HCl solution with LiF; the volume-to-mass ratio of the HCl solution to LiF is (35-45) mL:(2-5) g; and / or The Ti3AlC2 ceramic powder has a particle size of 150 mesh to 250 mesh; and / or The volume-to-mass ratio of the etchant to the Ti3AlC2 ceramic powder is (40-50) mL:(1-3) g.

7. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S5, the volume ratio of the quaternary ruthenium complex to the MXene nanosheet aqueous solution is (0.5–2):(0.5–2); and / or In the aqueous solution of MXene nanosheets, the mass concentration of MXene nanosheets is 2 mg / mL to 8 mg / mL; and / or The quaternary ruthenium complex was mixed with an aqueous solution of MXene nanosheets and stirred at room temperature under an argon atmosphere in the dark for 10-15 hours. The mixture was then washed with deionized water until the supernatant was colorless and freeze-dried under vacuum to obtain the quaternary ruthenium complex MXene composite material.

8. The preparation method of the ruthenium complex MXene chitosan composite antibacterial hydrogel as described in claim 1, characterized in that, In step S6, the mass concentration of carboxymethyl chitosan in the mixed liquid system is 2.5%–3.5%, the mass concentration of tannic acid in the mixed liquid system is 3.5%–4.5%, and the mass concentration of the quaternary ruthenium complex MXene composite material in the mixed liquid system is 0.2%–0.8%; and / or Carboxymethyl chitosan, tannic acid, and the quaternary ammonium ruthenium complex MXene composite material obtained in step S5 were dissolved in deionized water, and then stirred and mixed for 20 to 30 seconds to obtain a mixture. After standing for 4 to 5 minutes, the ruthenium complex MXene chitosan composite antibacterial hydrogel was obtained.

9. A ruthenium complex MXene chitosan composite antibacterial hydrogel, characterized in that, The ruthenium complex MXene chitosan composite antibacterial hydrogel is prepared by any one of claims 1 to 8.

10. The application of a ruthenium complex MXene chitosan composite antibacterial hydrogel, characterized in that, The application of the ruthenium complex MXene chitosan composite antibacterial hydrogel prepared by the method of any one of claims 1 to 8 in the preparation of medical antibacterial drugs and wound repair materials.

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