A chitosan-modified clay-based aerogel wound dressing and a preparation method thereof

Abstract

The present application relates to the technical field of wound dressing, and particularly relates to a chitosan modified clay-based aerogel wound dressing and a preparation method thereof. The preparation method comprises the following steps: S1: adding clay minerals into deionized water to prepare a slurry, and adding acetic acid while stirring to obtain a clay mineral slurry; S2: dissolving chitosan in an acetic acid solution to prepare a chitosan sol; S3: continuously stirring and mixing the clay mineral slurry and the chitosan sol to obtain a sol; S4: immersing the sol in a metal cation solution first, and then immersing the sol in an anion salt solution to obtain a standing product; and S5: freeze-drying the standing product to obtain a composite aerogel. The present application successfully constructs a three-dimensional porous aerogel dressing, which not only retains the strong hemostatic ability of clay, but also significantly enhances the mechanical strength and antibacterial performance, and exhibits great potential in the treatment of high-exudation complex wounds such as diabetic foot ulcers and infected wounds.

Description

Technical Field

[0001] This invention relates to the field of wound dressing technology, and more particularly to a chitosan-modified clay-based aerogel wound dressing and its preparation method. Background Technology

[0002] Currently, common wound dressings on the market include traditional dressings (such as gauze), film dressings, hydrogel dressings, alginate dressings, foam dressings, silver ion dressings, and bioactive dressings, each with its unique advantages. The core advantage of current mainstream advanced wound dressings (such as hydrogels and films) lies in their ability to maintain a moist wound environment and effectively promote healing (e.g., autolytic debridement, epithelial migration). However, they share common limitations when managing highly exudative wounds: either excessive water absorption and swelling leads to a significant decrease in mechanical strength or even dissolution (e.g., hydrogels), or limited absorbency leads to exudate accumulation (e.g., films), both of which easily cause wound maceration, barrier failure, and the risk of secondary infection. These shortcomings severely restrict their application in complex exudative wounds.

[0003] Aerogels, as novel wound dressing materials, offer significant advantages in the treatment of complex wounds. Their unique nanoscale porous structure provides an ultra-high specific surface area and excellent permeability, enabling them to maintain extremely low density while possessing strong liquid absorption capacity, good drug loading, and sustained-release properties, making them ideal carriers. Natural clay minerals (such as kaolin and montmorillonite) are considered key raw materials for aerogel preparation due to their low toxicity, good biocompatibility, and excellent hemostatic properties (rapid liquid absorption and promotion of blood clotting). However, the fragility, poor mechanical properties, difficulty in removal, and lack of antibacterial properties of single-clay aerogels limit their application. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a chitosan-modified clay-based aerogel wound dressing and its preparation method.

[0005] The first objective of this invention is to provide a method for preparing a chitosan-modified clay-based aerogel wound dressing, comprising the following steps:

[0006] S1: Add clay minerals to deionized water to prepare a slurry with a mass fraction of 2-10%. While stirring, add acetic acid solution to obtain clay mineral slurry.

[0007] S2: Dissolve chitosan in acetic acid solution to prepare chitosan sol with a mass fraction of 2-10%;

[0008] S3: The clay mineral slurry obtained in step S1 and the chitosan sol obtained in step S2 are continuously stirred and mixed at a certain mass ratio to obtain a clay mineral-chitosan composite sol.

[0009] S4: The sol is first soaked in a metal cation solution, then soaked in an anion salt solution, and the product is left to stand.

[0010] S5: Freeze-dry the static product to obtain the composite aerogel, namely the chitosan-modified clay-based aerogel wound dressing.

[0011] Further, in step S1, the clay mineral is one of kaolin, montmorillonite, halloysite, and sepiolite; the clay mineral slurry is prepared by mechanically stirring at 8000-10000 rpm / min for 30-40 minutes.

[0012] Furthermore, the concentration of acetic acid in the clay mineral slurry is 2-4 wt%.

[0013] Furthermore, the concentration of acetic acid in the chitosan sol is 2-4 wt%.

[0014] Further, in step S3, the clay mineral slurry and the chitosan slurry are uniformly mixed at a mass ratio of (1~9): (9~1).

[0015] Furthermore, in step S4, the metal cation solution is one of MgCl2 solution, CuSO4 solution, ZnCl2 solution, and CaCl2 solution.

[0016] Furthermore, the mass concentration of the metal cation solution is 1-5%.

[0017] Furthermore, in step S4, the anionic salt solution is one of trisodium citrate solution and calcium carbonate solution; the mass concentration of the anionic salt solution is 1-5%.

[0018] Furthermore, in step S5, the freezing temperature is any temperature between -20°C and -196°C, and the drying time is 72 hours.

[0019] A second objective of this invention is to provide a chitosan-modified clay-based aerogel wound dressing prepared using the above-described preparation method.

[0020] The key technical point of this invention is:

[0021] Micro / Nano Hierarchical Structure Self-Assembly: A micron-sized framework network is constructed using clay minerals and combined with a chitosan matrix. Through a framework-guided in-situ mineralization strategy, a multi-level structure integrating a micron-sized framework support with a nano-mineralized layer is formed. This process avoids traditional surface modification steps, significantly increasing the material's specific surface area and functional interface density. Novel Ionic Crosslinking Enhancement Mechanism: Unlike traditional toxic crosslinking agents (such as glutaraldehyde), an aerogel network is constructed using the salting-out and mineralization synergistic effect of metal ion solutions. Unique structural reinforcement is achieved at the molecular / nanoscale, providing a safe and effective new approach to improving the mechanical properties of dressings (such as structural stability), while also exhibiting excellent biocompatibility. Multidimensional Synergistic Drug-Free Hemostasis and Antibacterial Effect: The aerogel's multi-level pores enrich platelets, clay minerals activate intrinsic coagulation pathways, and metal ions promote coagulation factor activation—a triple hemostatic mechanism—along with the dual antibacterial mechanism of chitosan and metal ions synergistically inhibiting bacterial growth, overcomes the limitations of relying on exogenous drugs, achieving highly efficient hemostasis and antibacterial dual functions. Advantages of this Invention

[0022] 1. The aerogel prepared in this invention is based on a three-dimensional interconnected hierarchical porous structure. Its surface energy regulation and capillary action synergistically endow the material with a high liquid absorption rate (mass-to-absorption ratio of 5-8) and liquid holding capacity. During the acute traumatic bleeding period, this material can rapidly absorb wound exudate and blood components, reduce local hematocrit, and accelerate the intrinsic coagulation cascade reaction, achieving a dual-mode hemostasis effect through physical and biochemical means.

[0023] 2. This invention is based on a composite aerogel system of synergistic cross-linking of metal cations and anions. The bacterial membrane structure is destroyed by the synergistic electrostatic interaction between the positive charge of the protonated amino group of chitosan and the metal cation, thereby achieving a highly efficient antibacterial function.

[0024] 3. The raw materials used in this invention meet biocompatibility standards. The prepared aerogel has been verified by hemolysis tests, and its hemolysis rate is consistently less than 5%, indicating that the red blood cell membrane integrity is well maintained when the material comes into contact with blood. Furthermore, this dressing immobilizes the active components through a three-dimensional network confinement effect, significantly reducing the shedding rate of micro- and nano-particles, and significantly reducing the risk of thrombosis caused by intravascular foreign body reactions compared to traditional powder formulations.

[0025] 4. Chitosan (a natural cationic polymer) is not only biocompatible and biodegradable, but its high-deacetylation products also exhibit excellent solubility and broad-spectrum antibacterial activity. A clay-chitosan composite has been successfully used to construct a three-dimensional porous aerogel dressing. This material retains the strong hemostatic ability of clay while significantly enhancing its mechanical strength and antibacterial properties, demonstrating great potential in the treatment of complex, highly exudative wounds such as diabetic foot ulcers and infected wounds. Attached Figure Description

[0026] Figure 1 Chitosan aerogel (CS(Mg) 2+), Comparative Example 2), Kaolin / Chitosan Aerogel (Kao-CS(Mg) 2+ Macroscopic physical image and microscopic SEM image of Example 4);

[0027] Figure 2 Kaolin (Kao), pure chitosan powder (Pure CS), chitosan aerogel (CS(Mg) 2+ Comparative Example 2), Kaolin-Chitosan / Magnesium Composite Aerogel (Kao-CS(Mg) 2+ XRD patterns of Example 4);

[0028] Figure 3 The ingredients are kaolin (Kao), pure chitosan powder (Pure CS), pure trisodium citrate powder (Pure TSC), and chitosan aerogel (CS(Mg). 2+ Comparative Example 2), Kaolin-Chitosan / Magnesium Composite Aerogel (Kao-CS(Mg) 2+ Infrared spectra of Example 4);

[0029] Figure 4 It consists of pure kaolinite (Kao), pure chitosan powder (Pure CS), and chitosan aerogel (CS(Mg)). 2+ Comparative Example 2) and Kaolin-Chitosan / Magnesium Composite Aerogel (Kao-CS(Mg) 2+ Comparative data of in vitro coagulation index in Example 3);

[0030] Figure 5 The aerogels are pure chitosan aerogel (CS Aerogel, Comparative Example 1), kaolin-chitosan aerogel (KAO-CS, Comparative Example 3), and kaolin-chitosan / magnesium composite aerogel (Kao-CS(Mg)). 2+ Example 3) In vitro coagulation index comparison test;

[0031] Figure 6 It consists of pure kaolinite (Kao), pure chitosan powder (Pure CS), and kaolin / chitosan aerogel (Kao-CS(Mg)). 2+ Example 2) shows the antibacterial effect against Escherichia coli (E. coli) and the antibacterial effect data;

[0032] Figure 7 It consists of pure kaolinite (Kao), pure chitosan powder (Pure CS), and kaolin / chitosan aerogel (Kao-CS(Mg)). 2+ Hemolysis index data for Example 3). Detailed Implementation

[0033] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0034] Example 1

[0035] Kaolin was added to deionized water to prepare a 6% (w / w) slurry. The slurry was stirred three times at 8000 r / min for 30 min each time to ensure thorough dispersion. Then, the resulting slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a kaolin slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 6 wt% chitosan sol.

[0036] The two were mixed at a mass ratio of 5:3 and magnetically stirred for 24 h to obtain a kaolin / chitosan composite sol.

[0037] The obtained sol was poured into a petri dish and placed in a 1% magnesium chloride solution for 24 h for cationic pre-crosslinking. Then it was transferred to a 1% trisodium citrate solution and placed for 24 h to complete anionic crosslinking.

[0038] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named Kao5-CS3(Mg 2+ 1%).

[0039] Example 2

[0040] Kaolin was added to deionized water to prepare a 6% (w / w) slurry. The slurry was stirred three times at 10000 r / min for 30 min each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a kaolin slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 6 wt% chitosan sol.

[0041] The two were mixed at a mass ratio of 3:7 and magnetically stirred for 24 h to obtain a kaolin / chitosan composite sol.

[0042] The obtained sol was poured into a petri dish and placed in a 2% magnesium chloride solution for 24 h for cationic pre-crosslinking. Then it was transferred to a 2% trisodium citrate solution and placed for 24 h to complete anionic crosslinking.

[0043] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named Kao3-CS7(Mg 2+ 2%).

[0044] Example 3

[0045] Kaolin was added to deionized water to prepare a 6% (w / w) slurry. The slurry was stirred three times at 8500 rpm for 30 minutes each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a kaolin slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 minutes to obtain a 6 wt% chitosan sol.

[0046] The two were mixed at a mass ratio of 7:3 and magnetically stirred for 24 h to obtain a kaolin / chitosan composite sol.

[0047] The obtained sol was poured into a petri dish and placed in a 2% magnesium chloride solution for 24 h for cationic pre-crosslinking. Then it was transferred to a 2% trisodium citrate solution and placed for 24 h to complete anionic crosslinking.

[0048] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named Kao7-CS3(Mg 2+ 2%).

[0049] Example 4

[0050] Kaolin was added to deionized water to prepare a 5% (w / w) slurry. The slurry was stirred three times at 9000 r / min for 30 min each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a kaolin slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 5 wt% chitosan sol.

[0051] The two materials were mixed at a mass ratio of 5:5 and magnetically stirred for 24 h to obtain a kaolin / chitosan composite sol. The resulting sol was poured into a petri dish and first placed in a 3% magnesium chloride solution for 24 h for cationic pre-crosslinking, and then transferred to a 3% trisodium citrate solution for 24 h to complete anionic crosslinking.

[0052] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named Kao5-CS5(Mg 2+ 3%).

[0053] Example 5

[0054] Montmorillonite was added to deionized water to prepare a 4% (w / w) slurry. The slurry was stirred three times at 8000 r / min for 30 min each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a montmorillonite slurry. Chitosan was separately dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 4 wt% chitosan sol. The two were mixed at a mass ratio of 5:3 and magnetically stirred for 24 h to obtain a montmorillonite / chitosan composite sol. The obtained sol was poured into a petri dish and first placed in a 1% copper sulfate solution for 14 h for cationic pre-crosslinking, then transferred to a 1% trisodium citrate solution and placed for 14 h to complete anionic crosslinking.

[0055] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named MMT5-CS3(Cu 2+ 1%).

[0056] Example 6

[0057] Halloysite was added to deionized water to prepare a 5% (w / w) slurry. The slurry was stirred three times at 8000 r / min for 30 min each time to ensure thorough dispersion. Then, the resulting slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a halloysite slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 5 wt% chitosan sol.

[0058] The two were mixed at a mass ratio of 2:8 and magnetically stirred for 10 hours to obtain halloysite / chitosan composite sol.

[0059] The obtained sol was poured into a petri dish and placed in a 2% copper sulfate solution for 7 hours for cationic pre-crosslinking. Then it was transferred to a 2% trisodium citrate solution and placed for 10 hours to complete anionic crosslinking.

[0060] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named HNTs2-CS8(Cu 2+ 2%.

[0061] Example 7

[0062] Kaolin was added to deionized water to prepare a 5% (w / w) slurry. The slurry was stirred three times at 10000 r / min for 30 min each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a kaolin slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 5 wt% chitosan sol.

[0063] The two were mixed at a mass ratio of 2:8 and magnetically stirred for 10 hours to obtain a kaolin / chitosan composite sol.

[0064] The obtained sol was poured into a petri dish and placed in a 3% calcium chloride solution for 20 hours for cationic pre-crosslinking. Then it was transferred to a 3% trisodium citrate solution and placed for 20 hours to complete anionic crosslinking.

[0065] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named Kao2-CS8 (Ca 2+ 3%.

[0066] Example 8

[0067] Kaolin was added to deionized water to prepare a 5% (w / w) slurry. The slurry was stirred three times at 10000 r / min for 30 min each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) of acetic acid was added while stirring to obtain a kaolin slurry. Separately, chitosan was dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 5 wt% chitosan sol.

[0068] The two were mixed at a mass ratio of 2:8 and magnetically stirred for 10 hours to obtain a kaolin / chitosan composite sol.

[0069] The obtained sol was poured into a petri dish and placed in a 1% zinc chloride solution for 20 hours for cationic pre-crosslinking. Then it was transferred to a 3% trisodium citrate solution and placed for 20 hours to complete anionic crosslinking.

[0070] The resulting gel was pre-frozen at -80 °C for 2 h and then freeze-dried for 72 h to obtain a composite aerogel prepared by stepwise crosslinking of anions and cations, which was named Kao2-CS8(Zn 2+ 1%.

[0071] Comparative Example 1

[0072] Preparation of pure chitosan aerogel (CS Aerogel)

[0073] Chitosan was dissolved in a 2% acetic acid solution and magnetically stirred for 30 min at room temperature to obtain a homogeneous 5 wt% chitosan sol. The resulting sol was then poured into a petri dish and freeze-dried for 72 h to obtain an aerogel. This sample was named CSAerogel.

[0074] Comparative Example 2

[0075] Preparation of chitosan aerogel (CS(Mg) 2+ ))

[0076] Chitosan was dissolved in a 2% acetic acid solution and magnetically stirred for 30 min at room temperature to obtain a homogeneous 5 wt% chitosan sol. The sol was then poured into a petri dish and placed in a 2% magnesium chloride solution for 20 h for cationic pre-crosslinking, followed by placement in a 2% trisodium citrate solution for 20 h to complete anionic crosslinking. Finally, the resulting gel was pre-frozen at -80 °C for 2 h and freeze-dried for 72 h to obtain a composite aerogel. This sample was named CS(Mg) 2+ 2%).

[0077] Comparative Example 3

[0078] Preparation of kaolin-chitosan aerogel (KAO-CS)

[0079] Kaolin was added to deionized water to prepare a 5% (w / w) slurry. The slurry was stirred three times at 10000 r / min for 30 min each time to ensure thorough dispersion. Then, the slurry was placed under magnetic stirring, and 2% (w / w) acetic acid was added while stirring to obtain a kaolin slurry. Chitosan was separately dissolved in a 2% acetic acid solution and stirred for 30 min to obtain a 5 wt% chitosan sol. The two solutions were then mixed at a mass ratio of 6:4 and magnetically stirred for 10 h to obtain a kaolin / chitosan composite sol. The resulting sol was poured into a petri dish, pre-frozen at -80 °C for 2 h, and then freeze-dried for 72 h to obtain a composite aerogel. This sample was named Kao-CS.

[0080] Figure 1 Chitosan aerogel (CS(Mg) 2+ ), Comparative Example 2), Kaolin / Chitosan Aerogel (Kao-CS(Mg) 2+ Macroscopic physical image and microscopic SEM image of Example 4.

[0081] Magnesium ions (Mg 2+ Modified kaolinite-chitosan composite aerogel (Kao-CS(Mg) 2+ Compared to pure chitosan aerogel (CS(Mg) 2+The macroscopic surface is smoother and flatter, attributed to the clay mineral filling of kaolinite enhancing mechanical strength; multi-scale microstructure shows that both have a three-dimensional network porous framework, but the introduction of kaolinite refines the pores, forming a macroporous-mesoporous hierarchical structure (50µm view); its surface roughness is significantly increased (20µm view), which is beneficial for cell adhesion and exudate management in wound dressing applications; high magnification (3µm) confirms Mg 2+ It coordinates with citrate ions in the system to form a crystalline phase in situ, thereby enhancing the functional properties of the material.

[0082] Figure 2 Kaolin (Kao), pure chitosan powder (Pure CS), chitosan aerogel (CS(Mg) 2+ Comparative Example 2), Kaolin-Chitosan / Magnesium Composite Aerogel (Kao-CS(Mg) 2+ XRD patterns of Example 4).

[0083] Pure kaolinite exhibits characteristic diffraction peaks on crystal planes (001) and (002), while pure chitosan shows typical polymer broadening peaks; while Kao-CS(Mg 2+ The retention of kaolinite characteristic peaks (12.4°, 24.8°) in the composite material indicates the integrity of the inorganic mineral phase structure. Peak broadening and intensity reduction confirm that chitosan molecules partially intercalate into the kaolinite interlayer or interact with surface hydroxyl groups, reducing interlayer order. Furthermore, CS(Mg) 2+ ) and Kao-CS(Mg 2+ No diffraction peaks for Mg(OH)₂ or MgO were detected in the samples, which is attributed to Mg. 2+ It forms an amorphous coordination complex with the hydroxyl / citrate carboxyl groups of chitosan; combined with the freeze-drying process to avoid the high-temperature crystallization process, the magnesium element exists in a highly dispersed state, lacking a long-range ordered structure, hence no characteristic diffraction signal in XRD. Therefore, kaolinite not only stably retains the mineral framework in the composite material, but also serves as a reaction site for organic intercalation and ionic coordination, strengthening the coupling effect of the organic-inorganic interface.

[0084] Figure 3 The ingredients are kaolin (Kao), pure chitosan powder (Pure CS), pure trisodium citrate powder (Pure TSC), and chitosan aerogel (CS(Mg). 2+ Comparative Example 2), Kaolin-Chitosan / Magnesium Composite Aerogel (Kao-CS(Mg) 2+ Infrared spectra of Example 4).

[0085] Figure 3 The display shows that CS(Mg) 2+ ) and Kao-CS(Mg 2+No obvious vibrational characteristic peaks of Mg(OH)2 or MgO crystals were observed in any of the samples. Combined with the XRD results, it can be concluded that Mg... 2+ It does not exist in a crystalline form, but rather forms an amorphous complex structure through multi-site coordination with the hydroxyl and citrate carboxyl groups of chitosan. Correspondingly, in CS(Mg... 2+ ) and Kao-CS(Mg 2+ In the original TSC sample, 1580 cm -1 With 1394cm -1 COO - The absorption peak undergoes a red shift and becomes enhanced, accompanied by a peak at 1303 cm⁻¹. -1 With 1277cm -1 The emergence of the new peak is attributed to the enhanced C–OH bending vibration, further confirming the presence of Mg. 2+ The coordination behavior of Kao-CS(Mg) 2+ The sample still retains the XRD diffraction peaks of kaolinite at 12.4° and 24.8°, as well as the FTIR characteristic absorption bands of Si–O and Al–OH, indicating the stable existence of the inorganic mineral framework. Notably, the broadening and weakening of the kaolinite characteristic peaks suggest intercalation or surface hydrogen bonding / coordination between the organic chitosan and the kaolinite layer, resulting in a tight interfacial bond between the chitosan segments and the inorganic framework. Based on this, Mg… 2+ The citrate group further forms a multi-point coordination network across the interface between the hydroxyl groups on the chitosan and kaolinite surfaces, thereby enhancing the organic-inorganic coupling at the molecular level. Therefore, kaolinite not only provides overall material stability as a rigid framework, but also provides reaction sites for chitosan intercalation and ionic coordination through its layered structure and surface hydroxyl groups, and interacts with Mg... 2+ – The citrate network collectively constructs a stable three-dimensional hierarchical pore structure. This interaction mode significantly enhances the pore integrity and synergistic stability of the composite material, laying the foundation for its excellent coagulation-promoting properties.

[0086] Figure 4 It consists of pure kaolinite (Kao), pure chitosan powder (Pure CS), and chitosan aerogel (CS(Mg)). 2+ Comparative Example 2) and Kaolin-Chitosan / Magnesium Composite Aerogel (Kao-CS(Mg) 2+ Comparative data of in vitro coagulation index in Example 3).

[0087] The coagulation indices of pure kaolin and chitosan powder were 7.5% and 68.5%, respectively, while those of chitosan aerogel (CS(Mg)) were higher. 2 +Due to the blood cell adsorption and enrichment effect of the three-dimensional porous network, the coagulation index is significantly reduced by 85% compared to the powder bulk; Kaolin / chitosan composite aerogel (Kao-CS(Mg) 2+ The coagulation index further decreased to 3.2%, and its synergistic enhancement stemmed from the dual mechanism of multi-level pore physical enrichment of blood cells and kaolin activation of the intrinsic coagulation pathway, achieving a breakthrough improvement in coagulation efficiency.

[0088] Figure 5 The aerogels are pure chitosan aerogel (CS Aerogel, Comparative Example 1), kaolin-chitosan aerogel (KAO-CS, Comparative Example 3), and kaolin-chitosan / magnesium composite aerogel (Kao-CS(Mg)). 2+ Example 3) In vitro coagulation index comparison test.

[0089] Single chitosan aerogels, relying on the positive charge generated after protonation of their amino groups, attract the negatively charged platelet surface. Simultaneously, their porous structure allows for liquid absorption and concentration of blood cells and coagulation factors, thus exhibiting a certain procoagulant ability. Kao-CS without magnesium impregnation incorporates kaolin, whose surface acts as a contact activator for factor XII in the intrinsic coagulation pathway. This kaolin forms a complex porous structure with the chitosan network, further enhancing liquid absorption and enrichment. However, the overall effect still primarily relies on physical adsorption and surface activation, resulting in limited pore stability. In contrast, Kao-CS (Mg...) prepared through stepwise anionic and cationic crosslinking... 2+ In Mg 2+ Based on the pre-crosslinking with chitosan amino / kaolin hydroxyl groups, further crosslinking is achieved through citrate and Mg... 2+ The material forms multi-point coordination compounds with chitosan, constructing a stable three-dimensional interpenetrating framework and a hierarchical porous system. This allows the material to maintain its structural integrity even after rapid liquid absorption, enabling efficient adsorption of blood and enrichment of platelets and coagulation factors. It is this synergistic effect of "stable pores + coordination compound cross-linking" that enables Kao-CS(Mg) to... 2+ Its coagulation properties are far superior to the former two, with the lowest coagulation index and the most significant hemostatic effect.

[0090] Figure 6 It consists of pure kaolinite (Kao), pure chitosan powder (Pure CS), and kaolin / chitosan aerogel (Kao-CS(Mg)). 2+ Example 2) shows the antibacterial effect of Escherichia coli (E. coli) and the antibacterial effect data.

[0091] Pure kaolin and chitosan powder have low antibacterial rates, while chitosan aerogel (CS(Mg)) has a lower rate. 2+ )) and kaolinite / chitosan composite aerogel (Kao-CS(Mg 2+The aerogel exhibits a 99.99% inhibition rate against Escherichia coli and Staphylococcus aureus. This potent efficacy stems from the synergistic mechanism of the aerogel, where the positively charged chitosan groups chemically disrupt the bacterial membrane, and the presence of Mg... 2+ It enhances ion interference and induces the generation of reactive oxygen species, overcoming the limitations of single-component antibacterial agents.

[0092] Figure 7 It consists of pure kaolinite (Kao), pure chitosan powder (Pure CS), and kaolin / chitosan aerogel (Kao-CS(Mg)). 2+ Hemolysis index data for Example 3).

[0093] Kaolin exhibits significant hemolytic activity due to its surface charge properties, and its interaction with erythrocytes can induce significant cell membrane damage. In contrast, chitosan-based aerogel materials demonstrate excellent biocompatibility in in vitro hemolysis experiments, with the hemolysis rate consistently remaining below the safe threshold of 5%. Notably, the hemolysis index of the kaolin-chitosan aerogel prepared through a composite process is reduced by more than 90% compared to the pure kaolin system. This confirms that the chitosan molecular network effectively antagonizes the hemolytic toxicity of kaolin particles through charge neutralization and interfacial modification. This phenomenon is mainly attributed to the fact that the three-dimensional porous structure formed by the two-phase composite significantly reduces the probability of direct contact between kaolin and blood cells.

[0094] For any points not covered above, existing technologies shall apply.

[0095] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of preparing a chitosan-modified clay based aerogel wound dressing, characterized by, The method comprises the following steps: S1: adding clay minerals into deionized water to prepare a slurry with a mass fraction of 2-10%, and adding acetic acid while stirring to obtain a clay mineral slurry; S2: dissolving chitosan in an acetic acid solution to prepare a chitosan sol with a mass fraction of 2-10%; S3: continuously stirring and mixing the clay mineral slurry obtained in step S1 and the chitosan sol obtained in step S2 according to a certain mass ratio to obtain a clay mineral-chitosan composite sol; S4: immersing the sol in a metal cation solution first and then in an anion salt solution to obtain a standing product; S5: freeze-drying the standing product to obtain a composite aerogel, i.e., the chitosan-modified clay-based aerogel wound dressing; In step S4, the metal cation solution is one of MgCl2 solution, CuSO4 solution, ZnCl2 solution, and CaCl2 solution; The mass concentration of the metal cation solution is 1-5%. In step S4, the anion salt solution is one of trisodium citrate solution and calcium carbonate solution; and the mass concentration of the anion salt solution is 1-5%.

2. The production method according to claim 1, wherein The clay mineral is one of kaolin, montmorillonite, halloysite, and sepiolite; and the clay mineral slurry is prepared by mechanical stirring at 8000-10000 rpm / min for 30-40 min.

3. The production method according to claim 1, wherein In the clay mineral slurry, the concentration of acetic acid is 2-4wt%.

4. The production method according to claim 1, wherein In the chitosan sol, the concentration of acetic acid is 2-4wt%.

5. The production method according to claim 1, wherein In step S3, the clay mineral slurry and the chitosan slurry are uniformly mixed according to a mass ratio of (1-9):(9-1).

6. The production method according to claim 1, wherein In step S5, the freezing temperature is any temperature ranging from -20℃ to -196℃, and the drying time is 72h.

7. A chitosan-modified clay-based aerogel wound dressing prepared by the preparation method of any one of claims 1-6.

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