Hydrogel dressing based on cyanine dye as well as preparation method and application of hydrogel dressing

Abstract

The invention discloses a hydrogel dressing based on cyanine dye as well as a preparation method and application of the hydrogel dressing, and belongs to the technical field of medical biological materials. The hydrogel dressing based on the cyanine dye provided by the invention comprises a network structure prepared from molybdenum disulfide nanosheets, modified cyanine dye molecules and four-arm sulfydryl polyethylene glycol, the modified cyanine dye molecule is prepared from Cy5.5 (COOH) 2 and double-bond hyaluronic acid. Wherein a thiol group in the four-arm sulfydryl polyethylene glycol and a double bond of HAMA-Cy5.5 (COOH) 2 are subjected to a click reaction of sulfydryl-olefin to form a carbon-sulfur bond, and an independent macromolecular chain forms a network structure; molybdenum elements in the molybdenum disulfide nanosheets are combined with four-arm sulfydryl polyethylene glycol through chelation coordination, so that the hydrogel has excellent structural stability, the synergistic effect of photothermal therapy and photodynamic therapy can be achieved, the microenvironment of bacterial infection wounds is remarkably improved, and the hydrogel has wide application prospects in preparation of biomedical materials.

Description

Technical Field

[0001] This application belongs to the technical field of biomedical materials, and particularly relates to a hydrogel dressing based on cyanine dye, its preparation method and application. Background Art

[0002] Cyanine dyes (abbreviated as Cy) are a class of organic dyes with strong fluorescence properties, commonly used in targeted fluorescence probes and live cell imaging. The conjugated structure of their molecules has the properties of generating ROS free radicals and heating under near-infrared light, enabling photothermal therapy (PTT) and photodynamic therapy (PDT). PTT and PDT have been widely used as alternative therapies to conventional antibiotic bactericidal therapies, with the advantages of low side effects and broad-spectrum antibacterial properties. For example, in the existing patented technology with the application publication number CN 117924318A, cyanine dyes can be used as antibacterial agents with PTT and PDT effects, blended in hyaluronic acid microneedles encapsulated and used as dressings to inhibit wound bacterial infections. However, in the hydrogel system, cyanine dyes have low water solubility, and directly embedding cyanine dyes into the hydrogel is prone to leakage of cyanine dyes during use, causing the gel dressing to fail quickly and significantly reducing the service life. Therefore, it is necessary to develop dressings with excellent comprehensive performance to expand the application scope.

[0003] In addition, infected wounds are prone to produce an inflammatory environment with a high ROS level. Conventional treatments require reducing the content of ROS free radicals in the microenvironment to facilitate the repair of wound skin. However, the PDT effect of cyanine dyes generating ROS free radicals is not conducive to this process. Based on this, the existing hydrogel materials have the following problems: one is that directly embedding cyanine dyes into the hydrogel has poor structural stability and is prone to leakage; the other is that cyanine dyes generate a large amount of ROS during the treatment of skin wounds, affecting wound healing. Summary of the Invention

[0004] This application discloses a hydrogel dressing based on cyanine dye, its preparation method and application, aiming to solve the technical problems of poor structural stability, easy leakage and affecting wound healing of the existing cyanine dye hydrogel dressing.

[0005] To achieve the above object, the technical solution of this application is:

[0006] The first aspect of this application provides a hydrogel dressing based on cyanine dye, comprising: a network structure made of molybdenum disulfide nanosheets, modified cyanine dye molecules and tetra-armed mercapto polyethylene glycol;

[0007] The modified cyanine dye molecule is made of Cy5.5(COOH) 2 and double-bonded hyaluronic acid.

[0008] Preferably, in combination with the first aspect, the modified cyanine dye molecule is connected to the four-arm mercapto polyethylene glycol by a carbon-sulfur bond;

[0009] The molybdenum disulfide nanosheet is chelated and coordinated with the four-arm mercapto polyethylene glycol.

[0010] Preferably, in combination with the first aspect, the thickness of the molybdenum disulfide nanosheet is 5-10 nm.

[0011] The second aspect of the present application provides a preparation method of the cyanine dye-based hydrogel dressing described in the first aspect, and the preparation method includes:

[0012] Dissolve Cy5.5(COOH) 2 , N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and double-bonded hyaluronic acid in N,N-dimethylformamide and react at room temperature, dialyze, and freeze-dry to obtain the modified cyanine dye molecule;

[0013] React the four-arm mercapto polyethylene glycol, MoS 2 nanosheet and the modified cyanine dye molecule in the dark at room temperature, add a photoinitiator, and irradiate with ultraviolet light to obtain the cyanine dye-based hydrogel dressing.

[0014] Preferably, in combination with the second aspect, the molar ratio of Cy5.5(COOH) 2 to double-bonded hyaluronic acid is 0.8-1.5:1.

[0015] Preferably, in combination with the second aspect, the mass ratio of the four-arm mercapto polyethylene glycol, MoS 2 nanosheet to the modified cyanine dye molecule is 25:30:2.

[0016] Preferably, in combination with the second aspect, after dissolving the activated carboxyl Cy5.5(COOH) 2 and double-bonded hyaluronic acid in N,N-dimethylformamide and reacting at room temperature, dialyze in a cellulose dialysis bag with a cut-off molecular weight of 14000 Da in ultrapure water for 3 days.

[0017] Preferably, in combination with the second aspect, the photoinitiator is IR 2959.

[0018] Preferably, in combination with the second aspect, when adding the photoinitiator and irradiating with ultraviolet light, the temperature is 50-60 °C and the time is 10 min.

[0019] The third aspect of the present application provides the application of the cyanine dye-based hydrogel dressing described in the first aspect or the cyanine dye-based hydrogel dressing prepared by the preparation method described in the second aspect in the preparation of biomedical materials.

[0020] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application at least include:

[0021] The hydrogel dressing based on cyanine dye provided by the present application is made of a network structure formed by molybdenum disulfide nanosheets, modified cyanine dye molecules and tetra-arm mercapto polyethylene glycol. On the one hand, the thiol groups in the tetra-arm mercapto polyethylene glycol react with the double bonds of HAMA-Cy5.5(COOH) 2 to form carbon-sulfur bonds through thiol-ene click reaction, forming a network structure of the hydrogel with independent macromolecular chains; molybdenum disulfide nanosheets are used as functional fillers, and molybdenum elements are combined with tetra-arm mercapto polyethylene glycol through chelation coordination, binding the molybdenum disulfide nanosheets in the hydrogel network, making the hydrogel have excellent structural stability; on the other hand, the modified cyanine dye molecules have excellent photothermal effects and will generate ROS during the treatment process. Molybdenum disulfide nanosheets have peroxidase-like activity and can scavenge ROS for functional compensation, thus greatly improving the skin inflammatory environment; finally, it can achieve the synergistic effect of photothermal therapy and photodynamic therapy, significantly improve the wound microenvironment, improve the skin healing efficiency, and has broad application prospects in the treatment of bacterial-infected skin defect wounds BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 1H NMR spectrum of 3-(5-carboxypentyl)-1,1,2-trimethyl-1H-benzo[e]indol-3-ium bromide provided by the embodiment of the present application;

[0024] Figure 2 1H NMR spectrum of Cy5.5(COOH) provided by the embodiment of the present application 2 ;

[0025] Figure 3 1H NMR spectrum of double-bonded hyaluronic acid provided by the embodiment of the present application;

[0026] Figure 4 1H NMR spectrum of the modified cyanine dye molecule provided by the embodiment of the present application;

[0027] Figure 5 TEM image of MoS 2 nanosheets provided by the embodiment of the present application;

[0028] Figure 6The photothermal heating curve graph of different hydrogels provided by the embodiments of the present application;

[0029] Figure 7 The photothermal sterilization performance graph of different hydrogels provided by the embodiments of the present application;

[0030] Figure 8 The antioxidant performance graph of different hydrogels provided by the embodiments of the present application;

[0031] Figure 9 The actual graph of the bacterial infection wounds of mice in different hydrogel treatment groups provided by the embodiments of the present application;

[0032] Figure 10 The HE staining graph of the wound tissue at the end of the treatment with different hydrogels provided by the embodiments of the present application. Detailed implementation manners

[0033] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0034] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the case of A alone, the case of B alone, and the case of both A and B existing simultaneously. Where A and B may be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0035] In the following description of this embodiment, the term "at least one" means one or more, and "a plurality" means two or more. "At least one (item)" or its similar expression below refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, "at least one (item) of a, b or c", or, "at least one (item) of a, b and c" can all represent: a, b, c, a-b (that is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

[0036] Those skilled in the art should understand that in the following description of the embodiments of the present application, the sequence number does not mean the order of execution. Some or all steps can be executed in parallel or successively, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0037] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0038] Those skilled in the art should understand that the numerical ranges in the embodiments of the present application should be understood as specifically disclosing each intermediate value between the upper and lower limits of the range. Each intermediate value between any stated value and the intermediate values within the stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0039] Unless otherwise specified, the technical / scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present application pertains. Although the present application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the embodiments or test examples of the present application. All documents mentioned in this specification are generally incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this application shall prevail.

[0040] It should be noted that all raw materials and reagents in the embodiments of the present application are purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0041] In a first aspect, the embodiments of the present application provide a hydrogel dressing based on cyanine dye, comprising: a network structure made of molybdenum disulfide nanosheets, modified cyanine dye molecules, and tetra-arm mercapto polyethylene glycol;

[0042] The modified cyanine dye molecule is made of Cy5.5(COOH) 2 and double-bonded hyaluronic acid.

[0043] Wherein, on the one hand, the thiol groups in the tetra-arm mercapto polyethylene glycol react with HAMA-Cy5.5(COOH) 2The double bonds undergo a thiol-ene click reaction to form carbon-sulfur bonds, forming a hydrogel network structure from independent macromolecular chains. Molybdenum disulfide nanosheets serve as functional fillers, chelating and coordinating molybdenum elements with tetra-armed thiol-terminated polyethylene glycol to incorporate the molybdenum disulfide nanosheets into the hydrogel network, endowing the hydrogel with excellent structural stability. On the other hand, the modified cyanine dye molecules have excellent photothermal effects and generate ROS during the treatment process. Molybdenum disulfide nanosheets have catalase-like activity to scavenge ROS for functional compensation, thus significantly improving the skin inflammatory environment. Finally, the synergistic effect of photothermal therapy and photodynamic therapy can be achieved, significantly improving the wound microenvironment and enhancing the skin healing efficiency, showing broad application prospects in the treatment of bacterial-infected skin defect wounds.

[0044] In the embodiments of the present application, the modified cyanine dye molecules are connected to tetra-armed thiol-terminated polyethylene glycol via carbon-sulfur bonds; the molybdenum disulfide nanosheets are chelated and coordinated to tetra-armed thiol-terminated polyethylene glycol. Among them, through an esterification reaction, the water-insoluble cyanine Cy5.5(COOH) 2 is grafted onto double-bonded hyaluronic acid to achieve the dissolution of Cy5.5(COOH) 2 in the hydrogel (aqueous solution). Tetra-armed thiol-terminated polyethylene glycol serves as a crosslinking agent, HAMA-Cy5.5(COOH) 2 serves as a monomer, and molybdenum disulfide nanosheets serve as functional fillers. The thiol groups in tetra-armed thiol-terminated polyethylene glycol can react with the double bonds of HAMA-Cy5.5(COOH) 2 through a thiol-ene click reaction to form C-S carbon-sulfur bonds, forming a hydrogel network structure from independent macromolecular chains. At the same time, the metal molybdenum elements on the molybdenum disulfide nanosheets can chelate and coordinate with tetra-armed thiol-terminated polyethylene glycol through the chelation of thiol with transition element metals, integrating the molybdenum disulfide nanosheets into the hydrogel network.

[0045] In the embodiments of the present application, the thickness of the molybdenum disulfide nanosheets is 5-10 nm. Among them, through the introduction of molybdenum disulfide nanosheets, with the photothermal effect and the mimetic enzyme activity of scavenging free radicals of molybdenum disulfide nanosheets, ROS in various substances such as biomacromolecules, chemical substances, and environmental pollutants can be catalytically decomposed, thereby reducing the toxicity of ROS during the wound healing process. Molybdenum disulfide nanosheets can degrade ROS, eliminate excess ROS at the wound, thereby reducing the inflammatory response, achieving ideal photothermal therapy (PTT) and photodynamic therapy (PDT), and being able to treat bacterial-infected skin defect wounds.

[0046] In a second aspect, the embodiments of the present application further provide a preparation method of the cyanine dye-based hydrogel dressing described in the first aspect, and the preparation method includes:

[0047] Dissolve Cy5.5(COOH)2 , N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, and double-bonded hyaluronic acid are dissolved in N,N-dimethylformamide and reacted at room temperature, dialyzed, and freeze-dried to obtain modified cyanine dye molecules;

[0048] The tetra-armed thiol polyethylene glycol, MoS 2 nanosheets, and modified cyanine dye molecules are subjected to a light-shielded reaction at room temperature, a photoinitiator is added, and ultraviolet light irradiation is carried out to obtain the cyanine dye-based hydrogel dressing.

[0049] It should be noted that in this application, the preparation methods of the Cy5.5(COOH) 2 and double-bonded hyaluronic acid are not particularly limited and can be self-made or purchased. This application does not particularly limit the adopted methods, and they are all within the protection scope of this application.

[0050] Synthesis of 3-(5-carboxypentyl)-1,1,2-trimethyl-1H-benzo[e]indol-3-ium bromide: Weigh 1,1,2-trimethyl-1H-benzo[e]indole (0.510 g, 2.44 mmol), 5-bromopentanoic acid (2.270 g, 11.6 mmol), and potassium iodide (0.202 g, 1.22 mmol) and add them to a 50 mL three-necked round-bottom flask. Dissolve with 10 mL of acetonitrile, purge with argon for 30 min, and then heat under reflux at 110 °C for 36 h. After the reaction is completed, the solvent is removed by rotary evaporation under reduced pressure. The residue is dissolved in 3 mL of dichloromethane, and then 3 mL of ether is added to precipitate a solid. The solid is filtered and dried in vacuo to obtain 0.649 g of a pink solid, and the yield is 82%. The NMR results are as Figure 1 shown.

[0051] Synthesis of cyanine Cy5.5(COOH) 2 : 3-(5-carboxypentyl)-2-((1E,3E,5E)-5-(3-(5-carboxypentyl)-1,1-dimethyl-1,3-dihydro-2H-benzo[e]indol-2-ylidene)pent-1,3-dien-1-yl)-1,1-dimethyl-1H-benzo[e]indol-3-ium bromide; Weigh 3-(5-carboxypentyl)-1,1,2-trimethyl-1H-benzo[e]indol-3-ium bromide (0.661 g, 2.04 mmol) and N-((1E,3E)-3-(benzylidene)prop-1-en-1-yl)aniline (0.396 g, 1.23 mmol) and add them to a 50 mL three-necked round-bottom flask. Dissolve with a mixed solution of 8 mL of acetic anhydride and 8 mL of triethylamine, purge with argon for 30 min, and then heat under reflux at 120 °C for 2 h. After the reaction is completed, the solvent is removed by rotary evaporation under reduced pressure. The crude product is purified by flash silica gel column chromatography (dichloromethane and methanol) to obtain 0.613 g of a dark green solid, and the yield is 44%. The NMR results are asFigure 2 As shown. The reaction equation is as shown in Equation (1):

[0052]

[0053] It should be noted that the synthesis of double-bonded hyaluronic acid (HAMA): Weigh 10 g of hyaluronic acid and add it to a 2000 mL single-necked round-bottom flask, dissolve it with 1000 mL of ultrapure water to prepare a 1%, w / v solution. At 4 °C, 29.6 mL of methacrylic anhydride was added dropwise to the solution, and the pH value of the solution was adjusted to 8 - 9 with 1 M NaOH solution, and the reaction was carried out at low temperature for 24 h. After the reaction was completed, the reaction solution was placed in a cellulose dialysis bag with a molecular weight cut-off of 14000 Da and dialyzed in ultrapure water for 3 days, and then vacuum freeze-dried to obtain a white solid. The NMR results are as Figure 3 shown. The reaction equation is as shown in Equation (2):

[0054]

[0055] In the embodiment of the present application, the molar ratio of the activated carboxyl Cy5.5(COOH) 2 to the double-bonded hyaluronic acid is preferably 0.8 - 1.5:1. Among them, by controlling the molar ratio of Cy5.5(COOH) 2 to the double-bonded hyaluronic acid, the double-bonded hyaluronic acid can be grafted onto the Cy5.5(COOH) 2 molecule, and the grafting amount of the double-bonded hyaluronic acid can be controlled.

[0056] In the embodiment of the present application, the mass ratio of the four-arm mercapto polyethylene glycol, MoS 2 nanosheets and the modified cyanine dye molecule is 25:30:2. Among them, by controlling the addition amount of each substance, excellent structural stability and comprehensive performance can be imparted to the hydrogel dressing.

[0057] In the embodiment of the present application, after dissolving the activated carboxyl Cy5.5(COOH) 2 and the double-bonded hyaluronic acid in N,N-dimethylformamide and reacting at room temperature, it was dialyzed in ultrapure water in a cellulose dialysis bag with a molecular weight cut-off of 14000 Da for 3 days. Among them, by controlling the retention of the macromolecules after the reaction in the dialysis bag and dialyzing in ultrapure water, the small molecule impurities in the dialysis bag were continuously diffused out, so as to achieve the purpose of separating and purifying the reaction product.

[0058] In the embodiment of the present application, the photoinitiator is IR 2959. When the photoinitiator is added and irradiated with ultraviolet light, the temperature is 50 - 60 °C and the time is 10 min. Among them, this photoinitiator can initiate the free radical polymerization reaction of monomers to form larger polymer molecular chains.

[0059] The third aspect of the present application provides the use of the cyanine dye-based hydrogel dressing described in the first aspect or the cyanine dye-based hydrogel dressing prepared by the preparation method described in the second aspect in the preparation of biomedical materials. Based on the above hydrogel dressing having excellent structural stability and being able to achieve the synergistic effect of photothermal therapy and photodynamic therapy, significantly improving the wound microenvironment, it has broad application prospects in the preparation of biomedical materials.

[0060] The technical solution of the present application will be further elaborated below in conjunction with specific embodiments.

[0061] Example 1

[0062] This example provides a preparation method of A1 - cyanine dye-based hydrogel dressing (HXM hydrogel), which specifically includes:

[0063] S101: Weigh Cy5.5(COOH) 2 (68.338 mg, 0.1 mmol), N,N'-dicyclohexylcarbodiimide (30.949 mg, 1.5 mmol) and 4-dimethylaminopyridine (24.434 mg, 0.2 mmol) and add them into a 50 mL single-neck round-bottom flask, dissolve with 5 mL of N,N-dimethylformamide, and react at room temperature for 1 h to activate the carboxyl group of cyanine Cy5.5(COOH). 2 Synthesis of modified cyanine dye molecule (cyanine Cy5.5(COOH) 2 grafted with double-bonded hyaluronic acid, HAMA-Cy5.5(COOH) 2 ): Weigh double-bonded hyaluronic acid (HAMA, 40.331 mg, 0.1 mmol) in a 50 mL single-neck round-bottom flask, dissolve it with a mixed solution of 2.5 mL of N,N-dimethylformamide and 7.5 mL of ultrapure water, add the above-obtained cyanine Cy5.5(COOH) 2 solution after activating the carboxyl group, and react at room temperature for 48 h. After the reaction is completed, the reaction solution is filled in a cellulose dialysis bag with a molecular weight cut-off of 14,000 Da and dialyzed in ultrapure water for 3 days, and then vacuum freeze-dried to obtain a dark green solid. The NMR results are as Figure 4 shown.

[0064] S102: Weigh 25 mg of tetra-armed thiol polyethylene glycol (4ARM-PEG5000-SH) and 2 mg of MoS 2 nanosheets and add them into a 25 mL single-neck round-bottom flask, ultrasonically dissolve and disperse with 3 mL of ultrapure water, and then add 30 mg of HAMA-Cy5.5(COOH) 2, stir in the dark at room temperature until completely dissolved, and finally add 3 mg of photoinitiator IR 2959 and continue stirring to dissolve. Transfer the obtained prepolymer solution to a mold and irradiate it with ultraviolet light at 60 °C for 10 min to obtain A1 - cyanine dye - based hydrogel dressing (HXM hydrogel).

[0065] Double - bond - modified hyaluronic acid and Cy5.5(COOH) 2 The reaction equation for preparing the modified cyanine dye molecule is shown in Equation 3:

[0066]

[0067] The MoS 2 nanosheets used in the examples of this application have a structure as Figure 5 shown.

[0068] Meanwhile, to verify the comprehensive performance of the cyanine dye - based hydrogel dressing prepared in the above examples, the following comparative examples are provided in this application for detailed elaboration.

[0069] Comparative Example 1

[0070] The preparation method of the B1 - hydrogel dressing (HX hydrogel) prepared in this comparative example specifically includes:

[0071] Weigh 25 mg of tetra - arm mercapto - polyethylene glycol (4ARM - PEG5000 - SH) and 30 mg of HAMA - Cy5.5(COOH) 2 Add them to a 25 - mL single - neck round - bottom flask, add 3 mL of ultrapure water, stir in the dark at room temperature until completely dissolved, then add 3 mg of IR 2959 and continue stirring to dissolve. Transfer the obtained prepolymer solution to a mold and irradiate it with ultraviolet light at 60 °C for 10 min to obtain the B1 - hydrogel dressing (HX hydrogel).

[0072] Comparative Example 2

[0073] The preparation method of the B2 - hydrogel dressing (HM hydrogel) prepared in this comparative example specifically includes:

[0074] Weigh 25 mg of tetra - arm mercapto - polyethylene glycol (4ARM - PEG5000 - SH) and 2 mg of MoS 2 nanosheets, add them to a 25 - mL single - neck round - bottom flask, ultrasonically dissolve and disperse with 3 mL of ultrapure water, then add 30 mg of HAMA, stir at room temperature until completely dissolved, and finally add 3 mg of IR 2959 and continue stirring to dissolve. Transfer the obtained prepolymer solution to a mold and irradiate it with ultraviolet light at 60 °C for 10 min to obtain the B2 - hydrogel dressing (HM hydrogel).

[0075] Comparative Example 3

[0076] The preparation method of the B3-hydrogel dressing (H hydrogel) prepared in this comparative example specifically includes:

[0077] Weigh 25 mg of tetra-armed thiol polyethylene glycol (4ARM-PEG5000-SH) and 30 mg of HAMA and add them to a 25 mL single-neck round-bottom flask. Add 3 mL of ultrapure water and stir at room temperature until completely dissolved. Then add 3 mg of IR 2959 and continue to stir and dissolve. Transfer the obtained prepolymer solution to a mold and irradiate it with ultraviolet light at 60 °C for 10 min to obtain the B3-hydrogel dressing (H hydrogel).

[0078] To explore the photothermal heating performance of the hydrogel, the photothermal performance of the hydrogel samples (HXM, HX, HM, and H) was characterized by a near-infrared thermal imaging system (885-2, Testo, Germany). The prepared samples were first soaked in PBS for 24 h for swelling treatment. Weigh 200 mg of the hydrogel sample and add it to a 2 mL centrifuge tube. Add 500 μL of ultrapure water and irradiate it with an 808 nm laser (2.0 W / cm 2 ) for 15 min, and record the temperature value every 30 s. In addition, in the same way, the photothermal performance of the HXM hydrogel sample under laser irradiation with different power densities (1.0, 1.5, and 2.0 W / cm 2 ) was studied, and the photothermal cycling stability of the HXM hydrogel at a power density of 2.0 W / cm 2 was also explored. The results are as Figure 6 shown, where (a) the temperature change curves of HXM, HX, HM, and H under NIR (2.0 W / cm 2 ); (b) the temperature change curves of HXM under different NIR power densities (1.0, 1.5, and 2.0 W / cm 2 ); (c) the cyclic on-off temperature curve of HXM under NIR (2.0 W / cm 2 ).

[0079] According to Figure 6 what is known, through the introduction of cyanine Cy5.5(COOH) 2 , the HXM hydrogel and the HX hydrogel have photothermal heating performance, and the photothermal performance is optimal at a power density of 2.0 W / cm 2 . The HXM hydrogel has excellent photothermal cycling stability under NIR (2.0 W / cm 2 ).

[0080] To explore the photothermal bactericidal performance of the hydrogel. Dilute the Staphylococcus aureus bacterial solution to 10 6CFU / mL, and 500 μL of the diluted bacterial solution was incubated with 200 mg of different hydrogel samples (HXM, HX, HM, and H). The experiment was divided into a near-infrared irradiation group (+NIR) and a non-near-infrared irradiation group (-NIR). Among them, the hydrogel samples without near-infrared irradiation were incubated with the bacterial solution at 37 °C for 25 min, while the hydrogel samples with near-infrared irradiation were first incubated with the bacterial solution for 10 min and then irradiated with an 808 nm laser (2.0 W / cm 2 ) for 15 min. Subsequently, the bacterial solution incubated with the hydrogel samples was diluted to 10 4 CFU / mL, and 100 μL of the bacterial solution was used for plate coating experiments on solid media. The plates were cultured in an incubator at 37 °C for 9 - 12 h, and the number of colonies formed was photographed and recorded. The results are as Figure 7 shown, where (A) is the colony photo of Staphylococcus aureus, and (B) is the survival rate of Staphylococcus aureus.

[0081] According to Figure 7 what is known, under near-infrared irradiation, the HM, HX, and HXM hydrogels all showed a killing effect on Staphylococcus aureus, and the HX and HXM hydrogels containing cyanine Cy5.5(COOH) 2 had a survival rate of Staphylococcus aureus basically of 0, indicating that the introduction of cyanine Cy5.5(COOH) 2 into the hydrogel achieved excellent antibacterial performance.

[0082] To verify the enzyme-mimicking activity of the hydrogel, the prepared hydrogel was tested for catalase-like activity, scavenging of hydroxyl radicals, and scavenging of superoxide anions.

[0083] 1) Catalase-like activity: The titanium sulfate colorimetric method was used to monitor the consumption of H 2 O 2 by the hydrogel samples (HXM, HX, HM, and H). 3 mL of H 2 O 2 (1 mM, diluted with PBS) and 200 mg of the hydrogel sample were incubated in an oven at 37 °C for 24 h. Then, 1 mL of the supernatant was placed in a 5 mL centrifuge tube, and 2 mL of the titanium sulfate solution (prepared by dissolving 1.33 mL of 24 wt% titanium sulfate solution and 8.33 mL of concentrated sulfuric acid in 50 mL of ultrapure water) was added. After reacting for 30 min, the ultraviolet absorption curve in the range of 300 - 600 nm was detected using an ultraviolet spectrophotometer.

[0084] 2) Scavenging of hydroxyl radicals: Non-fluorescent terephthalic acid can capture ·OH to form a fluorescent compound, 2-hydroxyterephthalic acid. In the presence of terephthalic acid (0.5 mM), H 2 O 2Add 200 mg of the hydrogel sample to 3 mL of PBS (1 mM), incubate the mixture in a shaker at 37 °C for 12 h, and detect the fluorescence spectrum of the solution using a fluorescence spectrophotometer.

[0085] 3) Scavenging of superoxide anions: Based on the ability to inhibit the photoreduction of nitroblue tetrazolium (NBT) in the NADH-NBT-PMS system, the scavenging ability of the hydrogel sample for superoxide anions was evaluated. Immerse 200 mg of the hydrogel sample in 4.5 mL of 16 mM Tris-HCl buffer (pH 8.0), add 300 μM NBT (0.5 mL), 468 μM NADH (0.5 mL), and then add 60 μM PMS (0.5 mL) to the mixture to initiate the reaction. Incubate the mixture at 37 °C for 5 min, and detect the ultraviolet absorption curve in the range of 400 - 700 nm using an ultraviolet spectrophotometer. Based on the absorbance of the blank sample at 560 nm, a decrease in the absorbance of the reaction mixture indicates an enhanced scavenging activity of superoxide anions. The results are as Figure 8 shown, where (a) the ultraviolet-visible spectrum of H 2 O 2 consumed after treatment with the hydrogel sample; (b) the fluorescence spectrum of ·OH scavenging; (c) the ultraviolet-visible spectrum of O 2 ·- scavenging.

[0086] According to Figure 8 what is known, the HM and HXM hydrogels containing molybdenum disulfide nanosheets have the ability to catalyze hydrogen peroxide, scavenge hydroxyl radicals and superoxide anions, while the H and HX hydrogels do not have this effect, indicating that introducing molybdenum disulfide nanosheets into the hydrogel can scavenge ROS in the environment.

[0087] Bacterial infection-type wound skin repair experiment of the hydrogel: Healthy male Kunming mice (30 - 40 g, purchased from Chengdu Dashuo Experimental Animal Co., Ltd.) were selected to construct a bacterial infection-type skin defect wound model to study the effects of hydrogel samples (HXM, HX, HM, and H) on wound repair at active sites. The mice were fed in the laboratory for three days to adapt to the environment, then the hair on the neck was shaved and the mice were anesthetized with a physiological saline solution of 1% sodium pentobarbital. The wound skin was disinfected with iodophor solution and 4% chlorhexidine gluconate. A full-thickness skin wound with a diameter of about 7 mm was made using a disposable skin biopsy punch. Finally, 10 μL of Staphylococcus aureus solution (concentration of 10 8(CFU / mL) was dropped on the wound for infection. The mice after dropping the bacterial solution were randomly divided into 10 groups (4 in each group) for different treatments: 1: HXM; 2: HXM + NIR; 3: HX; 4: HX + NIR; 5: HM; 6: HM + NIR; 7: H; 8: H + NIR; 9: PBS; 10: PBS + NIR. The wounds were measured and photographed at days 0, 3, 6, 8, and 10 to record the wound repair process, and the hydrogel samples were replaced when photographing the wounds. On day 10, all the experimental mice used were bled and sacrificed, and the wound surface tissues were fixed with 4% paraformaldehyde fixative, then dehydrated by a fully automatic dehydrator and embedded in paraffin. The samples were sectioned and dewaxed, stained with hematoxylin for 10 - 20 min, then rinsed with tap water for 2 min, differentiated with hydrochloric acid alcohol for 5 - 10 s, rinsed continuously for 2 min, placed in a weakly alkaline aqueous solution at 50 °C to bluing until blue appeared, rinsed again for 2 min, placed in 85% alcohol for 3 - 5 min, stained with eosin for 3 - 5 min, dehydrated with alcohol gradient after washing with water, cleared with xylene and sealed with neutral gum, observed under a microscope, and histological analysis was carried out. The test results are as Figure 9 and Figure 10 shown.

[0088] According to Figure 9 and Figure 10 it can be known that under near-infrared irradiation, the HXM hydrogel uses the synergistic photothermal effect of cyanine Cy5.5(COOH) 2 and MoS 2 nanosheets to kill bacteria, and MoS 2 nanosheets can scavenge ROS free radicals. The functional components in the hydrogel synergistically sterilize and anti-inflammatory to improve the bacterial infection and high ROS microenvironment around the wound. After the treatment, the wound closure is the best, the re-epithelialization at the wound is more complete, and the hair follicle formation is more complete, significantly promoting wound healing.

[0089] Therefore, the hydrogel dressing based on cyanine dye provided in this application has an excellent structural stability by forming a network structure made of molybdenum disulfide nanosheets, modified cyanine dye molecules, and tetra-arm thiol polyethylene glycol, can achieve the synergistic effect of photothermal therapy and photodynamic therapy, significantly improve the wound microenvironment, and improve the healing efficiency of the skin, and has a wide application prospect in the treatment of bacterial infection type skin defect wounds.

[0090] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0091] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A cyanine dye-based hydrogel dressing, characterized in that: It includes: a network structure made of molybdenum disulfide nanosheets, modified cyanine dye molecules and four-arm thiol polyethylene glycol; The modified cyanine dye molecule is made of Cy5.5(COOH)2 and double-bonded hyaluronic acid.

2. The cyanine dye-based hydrogel dressing according to claim 1, characterized in that: The modified cyanine dye molecule is connected to the four-arm thiol polyethylene glycol via a carbon-sulfur bond; The molybdenum disulfide nanosheet is chelated and coordinated with four-arm mercapto polyethylene glycol.

3. The cyanine dye-based hydrogel dressing according to claim 1, characterized in that: The thickness of the molybdenum disulfide nanosheet is 5-10 nm.

4. A method for preparing a cyanine dye-based hydrogel dressing according to any one of claims 1 to 3, characterized in that: The preparation method comprises: Cy5.5(COOH)2, N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and double-bonded hyaluronic acid are dissolved in N,N-dimethylformamide and reacted at room temperature, dialyzed and freeze-dried to obtain a modified cyanine dye molecule; The four-arm mercapto polyethylene glycol, MoS2 nanosheets and modified cyanine dye molecules are reacted in the dark at room temperature, a photoinitiator is added, and ultraviolet light is applied to obtain the cyanine dye-based hydrogel dressing.

5. The method for preparing a cyanine dye-based hydrogel dressing according to claim 4, characterized in that: The molar ratio of Cy5.5(COOH)2 to double-bonded hyaluronic acid is 0.8-1.5:

1.

6. The method for preparing a cyanine dye-based hydrogel dressing according to claim 4, characterized in that: The mass ratio of the four-arm mercapto polyethylene glycol, MoS2 nanosheets and modified cyanine dye molecules is 25:30:

2.

7. The method for preparing a cyanine dye-based hydrogel dressing according to claim 4, characterized in that: The activated carboxyl Cy5.5(COOH)2 and the double-bonded hyaluronic acid were dissolved in N,N-dimethylformamide and reacted at room temperature, and then dialyzed in ultrapure water for 3 days in a cellulose dialysis bag with a molecular weight cutoff of 14000 Da.

8. The method for preparing a cyanine dye-based hydrogel dressing according to claim 4, characterized in that: The photoinitiator is IR 2959.

9. The method for preparing a cyanine dye-based hydrogel dressing according to claim 4, characterized in that: The photoinitiator is added and the ultraviolet light is irradiated at a temperature of 50-60° C. for 10 minutes.

10. Use of the cyanine dye-based hydrogel dressing according to any one of claims 1 to 3 or the cyanine dye-based hydrogel dressing prepared by the preparation method according to any one of claims 4 to 9 in the preparation of biomedical materials.

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