Phenylboronic acid modified chitosan / aloin antibacterial hydrogel and preparation method thereof

Abstract

This invention relates to the field of biomedical materials technology, specifically to a phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel and its preparation method. The specific technical solution is as follows: First, chitosan is grafted with 4-carboxyphenylboronic acid to obtain phenylboronic acid-modified chitosan; then, chitosan-derived carbon quantum dots are dispersed in an aqueous acetic acid solution and used to dissolve the phenylboronic acid-modified chitosan, obtaining a carbon quantum dot-containing phenylboronic acid-modified chitosan solution; subsequently, this solution is mixed with an aloe vera glycoside solution and crosslinked into a gel under alkaline conditions, followed by standing, water bath, dialysis, and freeze-drying to obtain the target product. The resulting hydrogel possesses self-healing properties, antibacterial properties, and fluorescent tracer functions. This preparation method is simple and mild, and the resulting hydrogel has application value in the fields of antibacterial dressings, wound covering materials, and functional biomedical materials.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, specifically to a phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel and its preparation method, and more particularly to a carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe-glycoside self-healing antibacterial hydrogel and its preparation method. Background Technology

[0002] Wound healing is a complex physiological process involving multiple stages, including hemostasis, inflammation regulation, tissue proliferation, and remodeling. For infected wounds, persistent bacterial colonization and biofilm formation can easily induce long-term inflammatory responses, disrupting the local tissue repair microenvironment and leading to delayed wound closure or even the development of chronic, difficult-to-heal wounds. These wounds typically require long treatment periods and frequent nursing care, placing a significant physiological and economic burden on patients. Therefore, developing novel functional dressing materials that meet the needs of infected wound repair has become an important research direction in the field of biomedical materials.

[0003] Currently, traditional wound dressings such as gauze, bandages, and cotton pads, while providing basic coverage, isolation, and exudate absorption, generally suffer from insufficient moisturizing capacity, easy adhesion to newly formed tissue, limited antibacterial properties, and the potential for secondary damage during dressing changes. They are particularly inadequate to meet the comprehensive needs of infected wounds for maintaining a moist environment, local antibacterial protection, and tissue-friendly contact. Hydrogels, with their high water content, good flexibility, biocompatibility, and extracellular matrix-like three-dimensional network structure, can provide a relatively moist repair environment for wounds and facilitate gas exchange and exudate management, showing promising application prospects in wound dressings and tissue repair. However, existing hydrogel dressings still have certain shortcomings. On the one hand, many hydrogels rely on ordinary physical cross-linking or static chemical cross-linking to form a network. When subjected to stretching, compression, shearing, or localized damage, their internal structure is prone to irreversible damage, lacking self-healing capabilities and making them unsuitable for use in scenarios involving skin bending, joint movement, and dynamic wound deformation. On the other hand, conventional hydrogels typically lack stable intrinsic antibacterial properties and often require additional loading of antibiotics, silver ions, or other antibacterial agents. This not only increases the complexity of preparation but may also lead to problems such as drug resistance, biotoxicity, burst release effects, or uncontrollable long-term release. While some self-healing or antibacterial hydrogels have improved individual properties, they still struggle to achieve a synergistic balance in self-healing, antibacterial protection, biosafety, and functional visualization.

[0004] In recent years, to improve the antibacterial properties and functional integration of hydrogel dressings, researchers have often enhanced their anti-infection capabilities by loading antibiotics, silver ions, metal oxide nanoparticles, or other antibacterial active ingredients. However, this strategy still has certain limitations. Antibiotic components may pose a risk of drug resistance, and silver ions and some metal nanoparticle antibacterial agents may exhibit biotoxicity, uncontrollable release, or local irritation during long-term use. Furthermore, the compatibility between exogenous antibacterial components and the hydrogel network is limited, easily leading to uneven dispersion, burst release, or functional attenuation. For infectious wound dressings, ideal functional components should not only enhance antibacterial protection but also possess excellent aqueous dispersibility, biocompatibility, and interaction with the hydrogel matrix to avoid the safety and stability issues associated with relying solely on free antibacterial agents.

[0005] Besides their antibacterial properties, existing hydrogel dressings generally lack in-situ visualization capabilities during practical use. While the degree of wound healing can be initially assessed under visible light by observing wound area, color, exudate, and crusting, this observation relies heavily on visual experience and is easily affected by factors such as lighting conditions, dressing transparency, wound exudate, and viewing angle. This makes it difficult to accurately reflect the actual coverage, residual state, and boundaries of unhealed areas of the dressing on the wound. Especially when the wound gradually shrinks or the dressing shifts or falls off, traditional dressings struggle to visually indicate whether they still cover the effective treatment area. Therefore, endowing hydrogel dressings with fluorescent tracer or visual identification functions can help determine the distribution, coverage, and residual unhealed areas of the dressing, thereby improving the accuracy of wound care and the convenience of material use.

[0006] Carbon quantum dots (CQDs) are a class of small-sized carbon-based nanomaterials rich in surface functional groups and exhibiting fluorescence response properties, showing potential applications in bioimaging, antibacterial materials, and functional hydrogels. In particular, CQDs prepared from natural polymers such as chitosan as carbon sources typically contain hydrophilic or active functional groups such as hydroxyl, carboxyl, and amino groups on their surface, exhibiting good compatibility with chitosan-based hydrogel systems. They can be uniformly dispersed in the hydrogel network and form hydrogen bonds, electrostatic interactions, or other non-covalent interactions with polymer segments. On one hand, CQDs can serve as fluorescent functional components, endowing hydrogels with visual tracking capabilities, allowing the dressing coverage area and residual state to be identified under ultraviolet light. On the other hand, their small size and abundant surface functional groups enhance their contact with bacterial surfaces and can produce synergistic antibacterial effects with natural active components such as chitosan and aloin. Compared to traditional metal antibacterial agents or simple fluorescent dyes, chitosan-derived CQDs are more suitable for constructing biomedical hydrogel dressings due to their milder source, matrix compatibility, and functional versatility.

[0007] Therefore, how to organically combine dynamic self-healing networks, intrinsic antibacterial capabilities, fluorescent tracer functions, and good biocompatibility while maintaining a mild and simple hydrogel preparation method remains a technical challenge in the development of infectious wound dressings. Based on this, the development of a self-healing antibacterial hydrogel with phenylboronic acid-modified chitosan as the main framework, aloin as the dynamic cross-linking component, and chitosan-derived carbon quantum dots as the functional enhancement component not only improves the material's antibacterial protection against infectious wounds but also enables in-situ visual monitoring of dressing coverage and unhealed areas through the fluorescence response of carbon quantum dots. This is of great significance for improving the functional integration and practical application adaptability of hydrogel dressings. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a phenylboronic acid-modified chitosan / aloe glycoside antibacterial hydrogel and its preparation method, thereby solving the problems of insufficient antibacterial properties, poor self-healing ability, difficulty in restoring damaged structures, lack of visual tracking function, and difficulty in achieving comprehensive performance in existing wound repair hydrogel materials.

[0009] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a method for preparing phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel, comprising the following steps: S1. Chitosan is modified with phenylboronic acid to obtain phenylboronic acid-modified chitosan; S2. Chitosan-derived carbon quantum dots are dispersed in an acidic aqueous solution to obtain a carbon quantum dot dispersion. S3. Dissolve the phenylboronic acid-modified chitosan in the carbon quantum dot dispersion to obtain a carbon quantum dot-containing phenylboronic acid-modified chitosan solution; dissolve aloin in an organic solvent to obtain an aloin solution; S4. After mixing the carbon quantum dot-containing phenylboronic acid modified chitosan solution with the aloe glycoside solution, add an alkaline solution and let it stand to react and form a gel. S5. The gel obtained in step S4 is subjected to water bath treatment, cooling, dialysis and freeze drying to obtain carbon quantum dot-enhanced phenylboronic acid modified chitosan / aloe glycoside antibacterial hydrogel.

[0010] Preferably, in step S1, the process of modifying the chitosan with phenylboronic acid is as follows: (1) Dissolve chitosan in an aqueous acetic acid solution to obtain a chitosan solution; (2) Dissolve 4-carboxyphenylboronic acid in dimethyl sulfoxide, and add buffer, 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole monohydrate for light-protected activation to obtain 4-carboxyphenylboronic acid activated solution. (3) The 4-carboxyphenylboronic acid activating solution was added to the chitosan solution for reaction. After the reaction was completed, the mixture was dialyzed and freeze-dried to obtain phenylboronic acid modified chitosan.

[0011] Preferably, the chitosan is dissolved in an aqueous acetic acid solution with a mass fraction of 0.5%, the pH of the reaction system is 5.6-5.9, and the buffer solution is MES buffer.

[0012] Preferably, the mass ratio of chitosan, 4-carboxyphenylboronic acid, 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole monohydrate is 1:0.10-0.50:0.15-0.65:0.10-0.50.

[0013] Preferably, the activation time of the 4-carboxyphenylboronic acid is 10-30 min; the 4-carboxyphenylboronic acid activation solution is added to the chitosan solution for 20-40 min, and the light-protected reaction time after addition is 5-9 h.

[0014] Preferably, in step S2, the preparation process of the chitosan-derived carbon quantum dots is as follows: chitosan is dissolved in an aqueous acetic acid solution to obtain a chitosan-acetic acid solution; the chitosan-acetic acid solution is transferred to a reaction vessel and subjected to hydrothermal reaction at 160-210℃ for 6-12 hours; after the reaction is completed, the solution is cooled to room temperature, the supernatant is collected by centrifugation, the supernatant is dialyzed and then freeze-dried to obtain chitosan-derived carbon quantum dots.

[0015] Preferably, in step S2, the acidic aqueous solution is a 1% (w / w) acetic acid aqueous solution, and the concentration of the carbon quantum dots in the acidic aqueous solution is 0.05-0.50 mg / mL; In step S4, the alkaline solution is a 1% sodium hydroxide aqueous solution. After adding the alkaline solution, the mixture is allowed to stand for 12-24 hours to form a gel.

[0016] Preferably, in step S3, the mass ratio of the phenylboronic acid-modified chitosan to aloe glycoside is 4-6:1.

[0017] Correspondingly, a carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel is provided. The hydrogel uses phenylboronic acid-modified chitosan as the main framework, aloe-glycoside as the dynamic cross-linking component, and chitosan-derived carbon quantum dots as the functional enhancement component. The hydrogel has self-healing properties, antibacterial properties, and fluorescent tracer functions.

[0018] Accordingly, the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe glycoside antibacterial hydrogel prepared by the aforementioned method is used in the preparation of medical antibacterial materials, wound covering materials, or biomedical materials with fluorescent tracer functions.

[0019] The present invention has the following beneficial effects: (1) The present invention uses phenylboronic acid modified chitosan as the main skeleton and aloin as the dynamic cross-linking component. It utilizes the reversible interaction between the phenylboronic acid group and the polyhydroxy structure of aloin to construct a hydrogel network, so that the hydrogel can re-form dynamic connections after being cut, squeezed or locally damaged, thereby having good self-healing ability and improving its adaptability to the dynamic activity environment of the wound.

[0020] (2) The present invention introduces chitosan-derived carbon quantum dots as a functional enhancement component. The oxygen- or nitrogen-containing functional groups on the surface of the carbon quantum dots can form hydrogen bonds, electrostatic interactions or other non-covalent interactions with phenylboronic acid-modified chitosan and aloin, so that they are stably dispersed in the hydrogel network and endow the resulting hydrogel with fluorescent tracer function, which is beneficial for in-situ visualization and identification of dressing coverage, residue and unhealed areas.

[0021] (3) The hydrogel obtained by the present invention contains chitosan, aloin and chitosan-derived carbon quantum dots, which can have a synergistic effect in antibacterial protection. At the same time, the carbon quantum dots are mildly derived and have good compatibility with the chitosan-based hydrogel system, which helps to reduce the risks of biotoxicity, drug resistance and uncontrollable release that may be caused by traditional metal antibacterial agents or antibiotic additives, so that the obtained hydrogel has application value in the fields of antibacterial dressings, wound covering materials and functional biomedical materials. Attached Figure Description

[0022] Figure 1 Infrared spectra of chitosan, 4-carboxyphenylboronic acid, aloin, 4-carboxyphenylboronic acid-grafted chitosan and aloin-4-carboxyphenylboronic acid-grafted chitosan composite gels. Figure 2 The images show the wound healing process of different treatment groups in a Staphylococcus aureus infection wound model. The treatment groups are, in order, the Staphylococcus aureus infection group, the aloe vera glycoside group, and Example 3. The observation time points are, in order, D0, D2, D4, D6, D9, and D14. Figure 3 The figures show the wound healing effects of different treatment groups in the Staphylococcus aureus infection wound model. The left figure shows the wound healing rate over time, and the right figure shows the scab formation time of different treatment groups. Figure 4 The image shows the self-healing performance test results of the carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel prepared in Example 3. Figure 5 The rheological properties of the carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3 are shown in the figure. Figure 6The images show the antibacterial performance tests of different samples, which are, in order, the blank group, the chitosan group, the aloin group, the carbon quantum dot group, the 4-carboxyphenylboronic acid-grafted chitosan group, the Example 2 group, and the Example 3 group. Figure 7 Scanning electron microscope image of the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel prepared in Example 3; Figure 8 The contact angle test diagram is shown for the carbon quantum dot-reinforced phenylboronic acid modified chitosan / aloe glycoside antibacterial hydrogel prepared in Example 3. Figure 9 Three-dimensional fluorescence spectrum of carbon quantum dots; Figure 10 Fluorescence images of the composite gel prepared in Example 2 and the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3; Figure 11 This is a schematic diagram illustrating the use of the carbon quantum dot-reinforced hydrogel dressing prepared in this invention for in-situ visual monitoring of wound healing. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0025] This invention provides a method for preparing a phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel, comprising the following steps: S1. Chitosan is modified with phenylboronic acid to obtain phenylboronic acid-modified chitosan; Specifically: the process of modifying the chitosan with phenylboronic acid is as follows: (1) Chitosan was dissolved in an aqueous acetic acid solution with a mass fraction of 0.5% to obtain a chitosan solution; deionized water was added to the chitosan solution, and the pH of the system was adjusted to 5.6-5.9 using 2-N-morpholine ethanesulfonic acid buffer to obtain a pretreated chitosan solution; (2) Dissolve 4-carboxyphenylboronic acid in dimethyl sulfoxide, and add buffer (MES buffer, i.e. 2-N-morpholinoethanesulfonic acid), 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride (EDC•HCl) and 1-hydroxybenzotriazole monohydrate (HOBt·H2O) for light-protected activation. The activation time is 10-30 min, preferably 15 min, to obtain 4-carboxyphenylboronic acid activation solution. The mass ratio of chitosan, 4-carboxyphenylboronic acid, 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole monohydrate is 1:0.10-0.50:0.15-0.65:0.10-0.50.

[0026] (3) The 4-carboxyphenylboronic acid activating solution is added to the chitosan solution for a light-protected reaction. After the reaction is completed, the mixture is dialyzed for 1-3 days to remove unreacted small molecule impurities, and then freeze-dried to obtain phenylboronic acid modified chitosan. The 4-carboxyphenylboronic acid activating solution is added to the chitosan solution for 20-40 minutes, and the light-protected reaction time after addition is 5-9 hours, preferably 7 hours.

[0027] S2. Disperse carbon quantum dots (by ultrasound or stirring) in an acidic aqueous solution to obtain a carbon quantum dot dispersion; the acidic aqueous solution is a 1% (w / w) acetic acid aqueous solution, and the concentration of carbon quantum dots in the acidic aqueous solution is 0.05-0.50 mg / mL, preferably 0.10 mg / mL.

[0028] Specifically, carbon quantum dots are prepared from chitosan through hydrothermal carbonization, centrifugation, dialysis, and freeze-drying.

[0029] The preparation process of the carbon quantum dots is as follows: chitosan is dissolved in an aqueous acetic acid solution to obtain a chitosan-acetic acid solution; the chitosan-acetic acid solution is transferred to a reaction vessel and hydrothermally reacted at 160-210℃ (preferably 170℃) for 6-12 hours, preferably 8 hours; after the reaction, the mixture is cooled to room temperature and centrifuged (centrifugation speed 4000-8000 rpm, centrifugation time 10-30 min) to obtain the supernatant. The obtained supernatant is dialyzed (dialysis bag molecular weight cutoff 500-3500 Da, dialysis time 48-96 h) to remove unreacted small molecule components and soluble impurities; after dialysis, the mixture is freeze-dried to obtain carbon quantum dots, i.e., chitosan-derived carbon quantum dots. The amount of chitosan used is 3-8 g, the mass fraction of the aqueous acetic acid solution is 0.5-2%, and the volume of the aqueous acetic acid solution is 80-150 mL.

[0030] S3. Dissolve the phenylboronic acid-modified chitosan in the carbon quantum dot dispersion and stir until completely dissolved to obtain a carbon quantum dot-containing phenylboronic acid-modified chitosan solution; dissolve aloin in an organic solvent (preferably anhydrous ethanol) to obtain an aloin solution; the mass ratio of the phenylboronic acid-modified chitosan to aloin is 4-6:1.

[0031] S4. The carbon quantum dot-containing phenylboronic acid-modified chitosan solution is mixed with the aloin solution and allowed to stand for 5-10 minutes. An alkaline solution is then added, and the mixture is allowed to stand and react to form a gel. The alkaline solution is a 1% (w / w) sodium hydroxide aqueous solution. After adding the alkaline solution, the mixture is stirred evenly and allowed to stand for 12-24 hours to form a gel. The phenylboronic acid groups on the phenylboronic acid-modified chitosan molecular chain interact dynamically and reversibly with the polyhydroxy structures in the aloin molecules, thereby constructing a three-dimensional cross-linked network and endowing the resulting gel with self-healing ability. The carbon quantum dots are dispersed in the phenylboronic acid-modified chitosan / aloe-glycoside hydrogel network. Their surface oxygen- or nitrogen-containing functional groups can form hydrogen bonds, electrostatic interactions, or other non-covalent interactions with chitosan segments, phenylboronic acid groups, and aloin molecules, ensuring the stable distribution of carbon quantum dots within the gel network.

[0032] S5. The gel obtained in step S4 is subjected to water bath treatment, cooling, dialysis, and freeze-drying to obtain a carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel. The water bath treatment temperature is 35-45℃, preferably 40℃, and the water bath treatment time is 0.5-2h, preferably 1h; the dialysis time is 0.5-2d, preferably 1d.

[0033] This invention provides a phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel, particularly a carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside self-healing antibacterial hydrogel. The hydrogel uses phenylboronic acid-modified chitosan as the main framework, aloe vera glycoside as the dynamic cross-linking component, and carbon quantum dots as the functional reinforcing component. A three-dimensional network structure is constructed through the dynamic reversible interaction between the phenylboronic acid groups and the polyhydroxyl structures of aloe vera glycoside. The hydrogel obtained by this invention has a loose and porous network morphology and possesses self-healing properties, antibacterial properties, and fluorescent tracer functionality.

[0034] Specifically, the carbon quantum dots are chitosan-derived carbon quantum dots, which have good compatibility with chitosan-based hydrogel systems, thus improving the biocompatibility and safety of the hydrogel materials. The carbon quantum dots are dispersed within the hydrogel network and impart fluorescent tracer functionality to the hydrogel, facilitating the visual identification of the hydrogel's distribution, coverage, and residue during use. The carbon quantum dots, along with chitosan and aloin, work synergistically to give the resulting hydrogel an antibacterial effect. This invention provides an application of the phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel prepared by the above method in the preparation of medical antibacterial materials, wound dressing materials, or biomedical materials with fluorescent tracer functionality.

[0035] The present invention will be further described below with reference to specific embodiments.

[0036] Example 1 A method for preparing 4-carboxyphenylboronic acid-grafted chitosan, comprising the following steps: (1) Weigh 1.000g of chitosan and add it to 30mL of 0.5% acetic acid aqueous solution. Stir magnetically at room temperature until completely dissolved to obtain chitosan solution.

[0037] (2) Add 15 mL of deionized water to the obtained chitosan solution, adjust the pH of the system to 5.8 using MES buffer, then bring the volume to 50 mL and stir evenly to obtain the pretreated chitosan reaction solution.

[0038] (3) Weigh 0.135g of 4-carboxyphenylboronic acid, add it to 2mL of dimethyl sulfoxide, and stir until completely dissolved; then add 8mL of MES buffer and mix well; then add 0.198g of EDC·HCl and 0.158g of HOBt·H2O, and activate in the dark for 15min to obtain 4-carboxyphenylboronic acid activation solution.

[0039] (4) The obtained 4-carboxyphenylboronic acid activation solution was slowly added dropwise to the above chitosan reaction solution within 30 min. After the addition was completed, the reaction was continued in the dark for 7 h.

[0040] (5) After the reaction is complete, the resulting reaction solution is placed in a dialysis bag and dialyzed in deionized water for 3 days. After the dialysis is complete, it is freeze-dried to obtain 4-carboxyphenylboronic acid grafted chitosan.

[0041] Example 2 A method for preparing an aloe-4-carboxyphenylboronic acid-grafted chitosan composite gel, comprising the following steps: (1) Weigh 0.255 g of the 4-carboxyphenylboronic acid-grafted chitosan obtained in Example 1, add it to 7.5 mL of 1% acetic acid aqueous solution, stir until completely dissolved, and obtain a 4-carboxyphenylboronic acid-grafted chitosan solution.

[0042] (2) Weigh 0.050g of aloin and add it to 2.5mL of anhydrous ethanol. Stir until completely dissolved to obtain an aloin solution.

[0043] (3) Mix the obtained 4-carboxyphenylboronic acid-grafted chitosan solution with aloe-emodin solution evenly and let stand for 10 min.

[0044] (4) Add 3.4 mL of 1% sodium hydroxide aqueous solution to the mixture in step (3), stir evenly and let stand for 24 h to form a gel.

[0045] (5) The obtained gel was placed in a 40°C water bath for 1 hour, and then cooled naturally at room temperature for 2 hours.

[0046] (6) The cooled gel was placed in a dialysis bag and dialyzed in running water for 1 day; after dialysis, it was freeze-dried to obtain aloe-4-carboxyphenylboronic acid-grafted chitosan composite gel.

[0047] Example 3 A method for preparing a carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel, comprising the following steps: (1) Preparation of carbon quantum dots and preparation of carbon quantum dot acetic acid dispersion: Weigh 5.000 g of chitosan and add it to 100 mL of 1% (w / w) acetic acid aqueous solution. Stir magnetically at room temperature until completely dissolved to obtain a chitosan acetic acid solution. Transfer the obtained chitosan acetic acid solution to a polytetrafluoroethylene-lined reactor and hydrothermally react at 170 °C for 8 h. After the reaction, allow the reactor to cool naturally to room temperature to obtain a dark brown reaction solution. Centrifuge the obtained reaction solution at 5500 rpm for 15 min to remove insoluble precipitates and collect the supernatant. Place the obtained supernatant into a dialysis bag with a molecular weight cutoff of 1000 Da and dialyze it in ultrapure water for 72 h. Change the dialysate regularly during the dialysis process to remove unreacted small molecules and soluble impurities. After the dialysis, freeze-dry the obtained dialysate to obtain chitosan-derived carbon quantum dots.

[0048] Weigh 0.75 mg of the obtained carbon quantum dots and add them to 7.5 mL of 1% acetic acid aqueous solution. Disperse the solution by ultrasonication for 10 min to obtain a carbon quantum dot acetic acid dispersion. The concentration of carbon quantum dots in the acetic acid aqueous solution is 0.10 mg / mL.

[0049] (2) Weigh 0.255g of the 4-carboxyphenylboronic acid-grafted chitosan obtained in Example 1, add it to the carbon quantum dot acetic acid dispersion above, and stir at room temperature until completely dissolved to obtain a carbon quantum dot-containing 4-carboxyphenylboronic acid-grafted chitosan solution.

[0050] (3) Weigh 0.050g of aloin and add it to 2.5mL of anhydrous ethanol. Stir until completely dissolved to obtain an aloin solution.

[0051] (4) Mix the obtained carbon quantum dot-containing 4-carboxyphenylboronic acid-grafted chitosan solution with the aloin solution evenly, let stand for 10 min, and obtain a mixed precursor system containing carbon quantum dots, 4-carboxyphenylboronic acid-grafted chitosan and aloin.

[0052] (5) Add 3.4 mL of 1% sodium hydroxide aqueous solution to the mixed precursor system in step (4), stir evenly and let stand for 24 h to form a carbon quantum dot-enhanced composite gel.

[0053] (6) The obtained gel was placed in a 40°C water bath for 1 hour, and then cooled naturally at room temperature for 2 hours.

[0054] (7) The cooled gel was placed in a dialysis bag and dialyzed in running water for 1 day; after dialysis, it was freeze-dried to obtain carbon quantum dot-enhanced phenylboronic acid modified chitosan / aloe glycoside antibacterial hydrogel.

[0055] Effect verification: Example 1 Fourier transform infrared spectroscopy was used to test chitosan, 4-carboxyphenylboronic acid, aloin, 4-carboxyphenylboronic acid-grafted chitosan, and aloin-4-carboxyphenylboronic acid-grafted chitosan composite gel (Example 2), respectively. The results are as follows: Figure 1 As shown.

[0056] Depend on Figure 1 It can be seen that, compared with the original chitosan, 4-carboxyphenylboronic acid grafted chitosan has higher concentrations at 1649, 1545, 1406-1329, and 1155-1031 cm⁻¹. -1 Significant peak position and shape changes were observed in certain regions, while the absorption related to the chitosan backbone glycoside backbone remained. Combined with 4-carboxyphenylboronic acid alone, the peaks at 1689, 1562 / 1512, 1352, and 1273–1016 cm⁻¹ were observed. -1 The comparison results of the characteristic absorption regions show that structural features related to 4-carboxyphenylboronic acid have appeared in the modified sample, indicating that 4-carboxyphenylboronic acid has been introduced into the chitosan system, supporting the successful modification of chitosan.

[0057] Furthermore, compared to 4-carboxyphenylboronic acid-grafted chitosan, the aloe-4-carboxyphenylboronic acid-grafted chitosan composite gel exhibits a higher viscosity at approximately 1715 cm⁻¹. -1 A new absorption peak appears at 1541 cm⁻¹. -1 and 1159-1070cm -1The absorption peaks in the region changed further, indicating that the introduction of aloin altered the local chemical environment of the modified chitosan, suggesting a significant interaction between it and 4-carboxyphenylboronic acid-grafted chitosan, forming a composite gel system.

[0058] Example 2: Testing the healing performance of infected wounds To evaluate the application effect of the hydrogel of the present invention in the repair of infected wounds, a Staphylococcus aureus infection wound model was established, and the Staphylococcus aureus infection group, Example 3 and aloe glycoside group were set up for comparison. The wound healing was observed on D0, D2, D4, D6, D9 and D14 respectively.

[0059] The specific process is as follows: I. Preparation of Staphylococcus aureus culture: 1. Strains resuscitation and passage Revive Staphylococcus aureus from cryopreservation tubes and incubate at 37°C for 18-24 hours until a single colony grows.

[0060] 2. Preparation of bacterial suspension ① Pick a single colony and inoculate it into 5 mL of TSB. Incubate at 37℃ and 200 rpm with shaking for 16-18 h to obtain the bacterial culture in the late logarithmic growth stage (overnight culture).

[0061] ② Transfer the overnight cultured bacterial solution to fresh TSB medium at a ratio of 1:100 (e.g., 100 μL of bacterial solution added to 10 mL of fresh TSB), and continue culturing at 37°C and 200 rpm in a shaker until the bacterial solution reaches the mid-logarithmic growth phase OD. 600 ≈0.5 (amplification culture).

[0062] 3. Measurement and adjustment of bacterial concentration ①OD 600 Measurement: During the culture process, the absorbance (OD) of the bacterial suspension at 600 nm was measured every 30 minutes using a spectrophotometer. 600 (Value). When OD 600 Stop culturing when the OD value reaches approximately 0.5-0.6. 600 =1.0 is approximately equal to 5 × 10 8 -8×10 8 (CFU / mL).

[0063] ② Establish the standard curve by taking: OD 600 For bacterial suspensions with specific values ​​(e.g., 1.0, 0.8, 0.6, 0.4, 0.2), perform serial dilutions of 10-fold (10... -1 10 -2 ,...,10 -7 After incubating at 37℃ for 24 hours, the number of colonies was counted.

[0064] ③ Bacterial suspension treatment: Centrifuge the bacterial suspension that has reached the target OD value (e.g., OD600≈0.5) at 4℃ and 4000rpm for 10min. Discard the supernatant, add 5mL of sterile PBS and centrifuge and wash again. Repeat the washing twice to remove culture medium and metabolites.

[0065] (If OD is measured) 600 When the concentration of the bacterial culture is 0.5, the bacterial concentration is 2×10⁻⁵. 8 If the concentration is CFU / mL, it needs to be diluted 20 times to obtain 1×10⁻⁶ CFU / mL. 7 (Final infection solution with CFU / mL) Dilute to the target concentration with sterile PBS: 3 × 10⁻⁶ 6 CFU / mL; 10 μL was injected into each wound (i.e., approximately 3 × 10⁻⁶ CFU / mL per wound). 5 CFU).

[0066] II. Infected Wound Model Based on the mice's weight, an appropriate dose of anesthetic was injected intraperitoneally to induce general anesthesia. Hair was removed from the mice's backs using a hair removal cream and a hair removal device. The skin at the hair removal site was disinfected with alcohol, then an 8mm skin punch was used to create a hole. The skin at the punched hole was then cut away with scissors, and 10μL of Staphylococcus aureus solution was evenly added to the wound to create an infected wound.

[0067] III. Carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe verain antibacterial hydrogel assembly The carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe glycoside antibacterial hydrogel prepared in Example 3 was applied to the infected wounds of mice at day 0, and no further administration was required.

[0068] IV. Aloe-glycoside group Take 2.5 mg of aloin and sprinkle it evenly on the infected wound of mice at D0. No further administration is required.

[0069] The results are as follows Figure 2 and Figure 3 As shown. By Figure 2 It was observed that the wounds in each group showed varying degrees of healing over time. In the early stages of healing, the Staphylococcus aureus infection group exhibited slower wound contraction, with more pronounced inflammatory reactions and crusting on the wound surface; some repair traces were still visible on day 14. The aloin group showed a certain degree of wound repair promotion compared to the Staphylococcus aureus infection group, with the wound area gradually shrinking over time. In contrast, the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe verain antibacterial hydrogel group showed more significant wound contraction from day 2 to day 9, with the wound essentially closed by day 14, demonstrating superior repair effects on infected wounds.

[0070] Depend on Figure 3As shown in the left figure, the wound healing rate of each group gradually increased with the extension of repair time, but there were significant differences between the different treatment groups. The carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe vera hydrogel group had a higher wound healing rate than the Staphylococcus aureus infection group and the aloe vera group at time points D2, D4, D6, and D9, indicating that the composite gel can promote the contraction and closure of infected wounds earlier. By D14, the wound healing rate of each group had further improved, with the composite gel group maintaining a high healing level.

[0071] Depend on Figure 3 As shown in the right figure, the scab formation time was longer in the Staphylococcus aureus infection group, slightly shorter in the aloe vera group, and significantly shorter in the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe vera antibacterial hydrogel group. This indicates that the antibacterial hydrogel can accelerate the early repair process of infected wounds. This result is consistent with the trend of wound healing rate, indicating that the composite gel has a promoting effect on the healing of infected wounds.

[0072] The above results demonstrate that the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel constructed in this invention can effectively promote wound contraction, improve wound healing rate, and shorten scab formation time in a Staphylococcus aureus-infected wound model. This may be because the chitosan-based material and quantum dots synergistically enhance antibacterial properties and wound adaptability; aloe vera glycoside, as a natural active component, helps improve the local repair environment; and the dynamic hydrogel network formed by phenylboronic acid-modified chitosan and aloe vera glycoside can maintain a moist microenvironment and cover the wound, thus providing favorable conditions for the repair of infected wounds. These results further prove that the hydrogel of this invention is suitable for antibacterial dressings, infected wound covering materials, and functional biomedical materials.

[0073] Example 3 The carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3 was stained with different colors and then cut into two parts. The cut surfaces of the two samples were brought into contact and bonded together, and then left to stand at room temperature to observe the interface changes. The results are as follows. Figure 4 As shown.

[0074] Depend on Figure 4 It can be seen that after the two parts of gel are re-contacted, as the standing time increases, the interface gradually adheres and tends to be continuous, and the original cutting boundary gradually weakens.

[0075] Furthermore, the gel sample, after being left to stand, could be held and lifted with tweezers, and no obvious breakage occurred at the joints, indicating that the separated gels could recombine and restore their integrity. These results demonstrate that the carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloebinin antibacterial hydrogel prepared in this invention possesses excellent self-healing properties.

[0076] Example of effect 4 The carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3 of this invention was subjected to frequency scanning tests using a rotational rheometer to verify its self-healing properties. The results are as follows: Figure 5 As shown.

[0077] The results showed that under the conditions of 25℃, 1% fixed strain (linear viscoelastic region), and frequency scanning of 0.1Hz-10Hz, the storage modulus G' of the original hydrogel sample was always significantly higher than the loss modulus G'', exhibiting a stable elastic-dominated gel state. After the sample was subjected to high shear damage and allowed to self-heal, its G' and G'' curves highly coincided with those of the original sample. It still maintained the gel characteristics of G' being much larger than G'' across the entire frequency range, and the storage modulus value showed almost no decay, with a retention rate of over 95%. This proves that the hydrogel of the present invention can quickly rebuild its three-dimensional network structure after being damaged by external force, and its mechanical properties are almost completely restored, demonstrating excellent self-healing performance.

[0078] Example 5: Antibacterial Performance Test To evaluate the antibacterial properties of different components and composite systems of the present invention, antibacterial performance tests were conducted on a blank group, a chitosan group, an aloin group, a carbon quantum dot group, a 4-carboxyphenylboronic acid-grafted chitosan group, a group from Example 2, and a group from Example 3. The results are as follows: Figure 6 As shown. Among them, Example 2 is an aloe-4-carboxyphenylboronic acid grafted chitosan composite gel, and Example 3 is a carbon quantum dot-reinforced phenylboronic acid modified chitosan / aloe-in antibacterial hydrogel.

[0079] Depend on Figure 6 It can be seen that the blank group had the highest number of colonies, indicating that bacteria could grow and reproduce normally without the addition of antibacterial materials. Compared with the blank group, the number of colonies in the chitosan group was reduced, indicating that chitosan itself has a certain antibacterial effect. The number of colonies in the aloin group and the carbon quantum dot group was also significantly less than that in the blank group, indicating that aloin and carbon quantum dots both have a certain inhibitory effect on bacterial growth. The number of colonies in the 4-carboxyphenylboronic acid-grafted chitosan group was further reduced compared with the blank group, indicating that the functionalized material obtained after 4-carboxyphenylboronic acid grafting modification of chitosan still has good antibacterial ability.

[0080] Furthermore, the number of colonies in the culture dishes of Example 2 was significantly less than that of the individual groups mentioned above, indicating that the overall antibacterial performance of the material was further improved after aloin and 4-carboxyphenylboronic acid were grafted onto chitosan to form a composite gel. Compared with Example 2, almost no obvious colony growth was observed in the culture dishes of Example 3, showing the strongest antibacterial effect, indicating that the introduction of carbon quantum dots into the composite gel system of Example 2 can significantly enhance the antibacterial performance of the material.

[0081] The above results indicate that the excellent antibacterial properties of the hydrogel obtained in Example 3 of this invention do not originate from the simple superposition of single components, but rather from the synergistic effect between chitosan, the 4-carboxyphenylboronic acid grafted structure, aloin, and carbon quantum dots. Specifically, chitosan provides the basic antibacterial activity, the 4-carboxyphenylboronic acid graft modification provides the active structural basis for the construction of the functionalized composite network, aloin, as a natural active component, participates in enhancing the antibacterial protective ability of the system, and carbon quantum dots further enhance the material's inhibitory effect on bacteria. Therefore, the carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3 possesses excellent antibacterial properties and is suitable for antibacterial dressings, infectious wound covering materials, and functional biomedical materials.

[0082] Example 6: Microscopic Morphology Analysis The carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3 was freeze-dried and then observed under a scanning electron microscope. The results are as follows: Figure 7 As shown. By Figure 7 As can be seen, the hydrogel obtained in Example 3 exhibits a distinct three-dimensional porous network structure with interconnected pores, relatively continuous pore walls, and a lamellar and wrinkled gel skeleton morphology. This structure indicates that 4-carboxyphenylboronic acid grafted chitosan and aloin can form a stable three-dimensional network through dynamic cross-linking, while the introduction of carbon quantum dots does not disrupt the main gel skeleton structure, and the hydrogel maintains a relatively intact porous morphology. This loose porous structure is beneficial for water absorption, wound exudate containment, and gas exchange, providing a relatively moist repair environment for the wound. Simultaneously, the continuous pore walls and cross-linked skeleton also help maintain the overall structural stability of the gel, giving it good morphological support when used as a wound dressing material. Combined with the antibacterial performance test results, it can be seen that the carbon quantum dot-reinforced composite gel prepared in this invention not only has good antibacterial activity but also possesses a porous microstructure suitable for use as a hydrogel dressing.

[0083] Example 7: Contact Angle Test The carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel prepared in Example 3 was subjected to a contact angle test to assess its surface wettability. The results are as follows: Figure 8 As shown. By Figure 8It can be seen that when water droplets come into contact with the surface of the hydrogel obtained in Example 3, they are rapidly absorbed within 0.1 seconds, and a stable water droplet morphology does not form on the surface, indicating that the hydrogel has good hydrophilicity and rapid water absorption capacity. This phenomenon indicates that there are a large number of hydrophilic groups on the surface and internal network of the gel, such as the amino and hydroxyl groups on the chitosan molecular chain, the polyhydroxy structure in the aloin molecule, and the oxygen- or nitrogen-containing functional groups on the surface of carbon quantum dots. These structures together enhance the interaction between the material and water molecules. Good hydrophilicity is beneficial for the hydrogel to quickly absorb wound exudate and maintain a relatively moist wound microenvironment. At the same time, water can quickly enter the gel network, which also helps the material to form sufficient contact with the wound surface, thereby improving its fit and comfort when used as a wound covering material. The above results show that the carbon quantum dot-reinforced phenylboronic acid modified chitosan / aloe-glycoside antibacterial hydrogel prepared in this invention has surface wetting characteristics suitable for use as a hydrogel dressing.

[0084] Example 8: Fluorescence Performance Testing of Carbon Quantum Dots The carbon quantum dots used in Example 3 were prepared into an aqueous dispersion, and their three-dimensional fluorescence spectrometry was measured using a fluorescence spectrophotometer. The results are as follows: Figure 9 As shown. By Figure 9 It was observed that the carbon quantum dot dispersion exhibited a significant fluorescence response signal in the three-dimensional fluorescence spectrum, with a strong emission region observed in the excitation wavelength range of approximately 300-350 nm, and the main emission signal concentrated around 400-450 nm. This result indicates that the carbon quantum dots prepared in this invention possess significant fluorescence emission characteristics and can be introduced into the hydrogel system as a fluorescent functional component. The fluorescence response of the carbon quantum dots may be related to their nano-carbon core structure, surface defect states, and oxygen / nitrogen-containing functional groups. Since these carbon quantum dots are prepared using chitosan as the carbon source via a hydrothermal reaction, their surface may retain a certain number of hydrophilic functional groups, which is beneficial for their dispersion in aqueous phase or acetic acid aqueous solution, and further embedding into the phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel network.

[0085] The above results demonstrate that the carbon quantum dots used in this invention can not only serve as a functional enhancement component in the construction of composite hydrogels, but also endow the resulting materials with a basis for fluorescence recognition. Combined with subsequent hydrogel fluorescence testing results, it can be further proven that the introduction of carbon quantum dots gives the hydrogel fluorescence tracer function, which is beneficial for visually observing the material distribution, coverage, and residue.

[0086] Example 9: Hydrogel Fluorescent Tracing Performance Test The aloin-4-carboxyphenylboronic acid-grafted chitosan composite gel prepared in Example 2 and the carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloebinin antibacterial hydrogel prepared in Example 3 were placed under ultraviolet light to observe their fluorescence response. The results are as follows: Figure 10 As shown. By Figure 10 It can be seen that the composite gel without carbon quantum dots did not show a significant fluorescence response under ultraviolet light, while the carbon quantum dot-enhanced hydrogel obtained in Example 3 showed a visible fluorescence signal, indicating that carbon quantum dots were successfully introduced into the gel system and could endow the hydrogel with fluorescence visualization characteristics. This result is consistent with... Figure 9 The results of the three-dimensional fluorescence spectroscopy test of carbon quantum dots corroborate each other, indicating that carbon quantum dots still retain a certain fluorescence emission capability in hydrogels.

[0087] The above results demonstrate that the carbon quantum dot-reinforced hydrogel prepared in this invention not only possesses self-healing and antibacterial functions but also exhibits fluorescent tracer properties. This property facilitates the visual observation of the distribution, coverage, and residue of the hydrogel material during use, thereby improving its convenience as a functional wound dressing or biomedical material.

[0088] Furthermore, such as Figure 11 As shown in the figure, this is an application diagram based on the fluorescence response results of carbon quantum dots, illustrating the in-situ visualization monitoring method of the hydrogel dressing of this invention during wound healing. The carbon quantum dot-reinforced hydrogel dressing (i.e., carbon quantum dot-reinforced phenylboronic acid-modified chitosan / aloe vera glycoside antibacterial hydrogel) can assist in identifying the covered and unhealed areas through fluorescence signals during wound healing. Under visible light conditions, the degree of wound healing can be initially observed through wound area and tissue morphology; under ultraviolet light irradiation, the unhealed areas covered by the carbon quantum dot-reinforced hydrogel dressing exhibit identifiable fluorescence signals, while the healed areas, no longer requiring hydrogel coverage, do not produce corresponding fluorescence responses. As the wound gradually heals, the residual unhealed area and the corresponding fluorescent area gradually shrink, thereby achieving in-situ visualization monitoring of the wound healing process, dressing coverage status, and residual location. This function helps to determine whether the dressing still covers the effective treatment area, avoiding dressing displacement, detachment, or uneven residue leading to insufficient local protection, and improving the operational accuracy and material application convenience during wound care.

[0089] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a phenylboronic acid-modified chitosan / aloin antibacterial hydrogel, characterized by comprising the following steps: Includes the following steps: ​ S1. Chitosan is modified with phenylboronic acid to obtain phenylboronic acid-modified chitosan; S2. Chitosan-derived carbon quantum dots are dispersed in an acidic aqueous solution to obtain a carbon quantum dot dispersion. S3. Dissolve the phenylboronic acid-modified chitosan in the carbon quantum dot dispersion to obtain a carbon quantum dot-containing phenylboronic acid-modified chitosan solution; dissolve aloin in an organic solvent to obtain an aloin solution; S4. After mixing the carbon quantum dot-containing phenylboronic acid modified chitosan solution with the aloe glycoside solution, add an alkaline solution and let it stand to react and form a gel. S5. The gel obtained in step S4 is subjected to water bath treatment, cooling, dialysis and freeze drying to obtain carbon quantum dot-enhanced phenylboronic acid modified chitosan / aloe glycoside antibacterial hydrogel.

2. The method of claim 1, wherein: In step S1, the process of modifying chitosan with phenylboronic acid is as follows: (1) Dissolve chitosan in an aqueous acetic acid solution to obtain a chitosan solution; (2) Dissolve 4-carboxyphenylboronic acid in dimethyl sulfoxide, and add buffer, 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole monohydrate for light-protected activation to obtain 4-carboxyphenylboronic acid activated solution. (3) The 4-carboxyphenylboronic acid activating solution was added to the chitosan solution for reaction. After the reaction was completed, the mixture was dialyzed and freeze-dried to obtain phenylboronic acid modified chitosan.

3. The method of claim 2, wherein: The chitosan was dissolved in an aqueous acetic acid solution with a mass fraction of 0.5%, and the pH of the reaction system was 5.6-5.

9. The buffer solution was MES buffer.

4. The method of claim 2, wherein: The mass ratio of chitosan, 4-carboxyphenylboronic acid, 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole monohydrate is 1:0.10-0.50:0.15-0.65:0.10-0.

50.

5. The preparation method according to claim 2, characterized in that: The activation time of the 4-carboxyphenylboronic acid is 10-30 min; the 4-carboxyphenylboronic acid activation solution is added to the chitosan solution for 20-40 min, and the reaction time in the dark after addition is 5-9 h.

6. The method of claim 1, wherein: In step S2, the preparation process of the chitosan-derived carbon quantum dots is as follows: chitosan is dissolved in an aqueous acetic acid solution to obtain a chitosan-acetic acid solution; the chitosan-acetic acid solution is transferred to a reaction vessel and subjected to hydrothermal reaction at 160-210℃ for 6-12 hours; after the reaction is completed, the solution is cooled to room temperature, the supernatant is collected by centrifugation, the supernatant is dialyzed and then freeze-dried to obtain chitosan-derived carbon quantum dots.

7. The method of claim 1, wherein: In step S2, the acidic aqueous solution is a 1% (w / w) acetic acid aqueous solution, and the concentration of the carbon quantum dots in the acidic aqueous solution is 0.05-0.50 mg / mL; In step S4, the alkaline solution is a 1% sodium hydroxide aqueous solution. After adding the alkaline solution, the mixture is allowed to stand for 12-24 hours to form a gel.

8. The method of claim 1 or 7, wherein: In step S3, the mass ratio of the phenylboronic acid-modified chitosan to aloe glycoside is 4-6:

1.

9. The carbon quantum dots enhanced phenylboronic acid modified chitosan / asiaticoside antibacterial hydrogel prepared by the method of claims 1-8, characterized in that: The hydrogel uses phenylboronic acid-modified chitosan as the main framework, aloin as the dynamic cross-linking component, and chitosan-derived carbon quantum dots as the functional enhancement component.

10. The application of the carbon quantum dot-enhanced phenylboronic acid-modified chitosan / aloe-glycoside antibacterial hydrogel of claim 9 in the preparation of medical antibacterial materials, wound covering materials, or biomedical materials with fluorescent tracer functions.

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