Antibacterial and hemostatic composite material and preparation method thereof

Abstract

The present invention relates to an antibacterial and hemostatic composite material and a preparation method thereof. The preparation method comprises the following steps: first reacting exfoliated graphene oxide with KH560 at 60°C to obtain coupled grafted graphene oxide (EGO); then reacting kaolin nanotubes with EGO at 80°C under vigorous stirring to obtain EGO-EK; then using a cross-linking agent and a catalyst, reacting a chitosan solution with EGO-EK to obtain a uniform suspension, and freeze-drying. The hemostatic composite material of the present invention has the characteristics of resisting bacterial infection, not prone to tissue adhesion to the wound surface, good mechanical properties, photothermal effect, excellent biocompatibility and rapid hemostasis ability, and can also accelerate the healing of bacterially infected wounds.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials, and in particular relates to an antibacterial and hemostatic composite material and a preparation method thereof. Background Art

[0002] Uncontrolled bleeding can cause significant casualties and losses. Therefore, timely and effective bleeding control is crucial to improve survival. However, without the assistance of hemostatic materials, the body's own coagulation process cannot effectively stop bleeding in a timely manner. In this context, the development of antimicrobial biomaterials that can effectively and rapidly stop bleeding is of great significance for the treatment of trauma patients.

[0003] Ideal hemostatic materials should not only rapidly control excessive bleeding but also be absorbable, biodegradable, non-antigenic, and biocompatible. While traditional gauze and bandages are simple to manufacture, inexpensive, have a certain hemostatic effect, and can be reused, they suffer from numerous drawbacks, such as bacterial growth, adhesion to the wound surface, and the potential for secondary bleeding and tissue damage during dressing changes. Consequently, technological advancements have led to the development of new hemostatic materials, including polymeric hemostatic materials such as collagen (Col), gelatin (GE), and chitosan (CS). Inorganic hemostatic materials, including kaolin, zeolite, and montmorillonite, are popular due to their high efficiency, ease of use, cost-effectiveness, and minimal tissue reactivity. Combat Gauze (Z-Medica), among others, is a kaolin-impregnated gauze.

[0004] However, most current hemostatic materials are single-purpose or suffer from various defects, failing to meet the requirements of an ideal hemostatic material. For example, collagen has poor tissue adhesion, porous zeolite generates significant heat when absorbing water from the blood, leading to wound inflammation, and chitosan hemostatic materials suffer from brittleness and inflexibility, poor hemostatic efficacy, poor tissue adhesion, and high cost. Inorganic hemostatic materials, such as zeolite, can cause thermal damage to surrounding tissues, while kaolin takes longer to control arterial bleeding. Furthermore, currently used inorganic hemostatic agents are not suitable for deep and non-compressible bleeding, and they also suffer from poor tissue adhesion and low bioactivity.

[0005] Therefore, there is an urgent need to explore composite antibacterial hemostatic materials with excellent hemostatic effect, rapid expansion ability to fill the wound cavity, appropriate tissue adhesion to avoid detachment from the wound, superior biocompatibility, and good antibacterial ability to promote tissue healing. Summary of the Invention

[0006] In view of the above-mentioned deficiencies in current technology, the present invention provides an antibacterial and hemostatic composite material and a preparation method thereof.

[0007] The first aspect of the present invention provides a method for preparing an antibacterial and hemostatic composite material, comprising the steps of:

[0008] S1: first reacting exfoliated graphene oxide with a coupling agent KH560 at 60°C to obtain coupled grafted graphene oxide EGO; then reacting kaolin nanotubes with the EGO at 80°C under vigorous stirring to obtain kaolin nanotube coupled grafted graphene oxide EGO-EK;

[0009] S2 uses a cross-linking agent and a catalyst to react the chitosan solution with EGO-EK to obtain a uniform suspension, which is then freeze-dried to obtain the antibacterial and hemostatic composite material.

[0010] First, graphene and kaolin nanotubes are combined through coupling grafting, and then combined with the polymer hemostatic material chitosan through cross-linking to obtain an inorganic-organic composite hemostatic material. The photothermal effect of graphene can also be utilized. The synthesis method is simple and inexpensive.

[0011] When coupling kaolin nanotubes and graphene oxide, the heating temperature must be 80°C. If the heating temperature is too low, the coupling agent KH560 cannot be fully activated to graft graphene oxide and kaolin nanotubes together; if the temperature is too high, it is easy to cause water evaporation, which is not conducive to the reaction.

[0012] Furthermore, in step S1, the mass ratio of exfoliated graphene oxide to KH560 is 1:4; and the mass ratio of kaolin nanotubes to EGO is 1:1.

[0013] Furthermore, the exfoliated graphene oxide is prepared by the following method: mixing graphite powder with concentrated sulfuric acid, then adding phosphorus pentoxide and potassium permanganate in sequence, and then reacting in a water bath at 80°C to obtain graphite oxide; then, mixing the obtained graphite oxide with concentrated sulfuric acid, adding potassium dichromate, and reacting at 35°C. After the reaction is completed, adding 30% H2O2 solution dropwise in an ice bath to react to obtain graphene oxide; finally, ultrasonic exfoliation is performed to obtain the exfoliated graphene oxide.

[0014] Furthermore, the kaolin nanotubes are prepared by the following method: kaolin, dimethyl sulfoxide and distilled water are mixed and stirred at 60°C for reaction, filtered and dried to obtain a kaolin-DMSO complex; the obtained dry kaolin-DMSO complex is dispersed in methanol, sealed and ultrasonicated, and then centrifuged to obtain a kaolin-CH3OH complex wet sample; the kaolin-CH3OH wet sample is then dispersed in a hexadecyltrimethylammonium chloride methanol solution, vigorously stirred at room temperature for 10 to 14 hours, and finally transferred to a reactor, reacted at 140 to 160°C for 10 to 14 hours, and after cooling, centrifuged, washed and dried to obtain the kaolin nanotubes.

[0015] Using flaky kaolin as raw material, by inserting organic matter between its layers, the hydrogen bonding between the layers is weakened, the distance between the layers is expanded, and its structure is insufficient to overcome the geometric stress and bends and deforms, thereby generating tubular kaolin nanotubes, which have better hemostatic ability than layered kaolin.

[0016] Furthermore, the kaolin particle size is ≤150 μm.

[0017] Furthermore, the kaolin: dimethyl sulfoxide: distilled water: hexadecyltrimethylammonium chloride methanol solution = 10 g: 100 mL: 9 mL: 50 mL, and the concentration of the hexadecyltrimethylammonium chloride methanol solution is 1 mol / L.

[0018] Furthermore, in step S2, the mass ratio of chitosan:EGO-EK is 5:1-3.

[0019] Furthermore, the crosslinking agent is EDC (1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride), and the catalyst is NHS (N-hydroxysuccinimide). The amount of EDC or NHS added is generally 0.2%-0.75% by weight of the chitosan. In a preferred embodiment, the mass ratio of EDC to NHS is 1:1.

[0020] Furthermore, the chitosan M W =50000, pH value of chitosan solution = 6.5-7, concentration is 1wt%.

[0021] Another aspect of the present invention also provides an antibacterial and hemostatic composite material prepared by the preparation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The hemostatic material of the present invention uses a cross-linking method to combine raw materials, and the synthesis method is safe and has no toxic side effects;

[0024] 2) The raw material modification method of the present invention is simple and can be made by modification. The method is simple, cheap, safe and reliable;

[0025] 3) The hemostatic material of the present invention cross-links the polymer hemostatic material chitosan with the inorganic hemostatic kaolin and adds graphene oxide. Compared with traditional single-function hemostatic materials, this material combines the functions of the polymer hemostatic material and the inorganic hemostatic material. It also utilizes the photothermal properties of graphene and combines it with photothermal therapy to further enhance the antibacterial effect. The resulting composite material integrates the three functions of hemostasis, anti-inflammatory, and antibacterial.

[0026] 4) The hemostatic composite material of the present invention has the advantages of resisting bacterial infection, not easily forming tissue adhesion with the wound surface, having good mechanical properties, photothermal effect, excellent biocompatibility and rapid hemostasis ability, and can also accelerate the healing of bacterially infected wounds, providing a reference for the development of antibacterial, hemostatic and healing-promoting composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a SEM analysis picture of an embodiment of the present invention;

[0028] Figure 2 The swelling water absorption test results of the embodiment of the present invention are as follows;

[0029] Figure 3 Compression performance test results of an embodiment of the present invention;

[0030] Figure 4 The in vitro antibacterial performance test results of the embodiments of the present invention are as follows;

[0031] Figure 5 The whole blood coagulation index evaluation result of the embodiment of the present invention;

[0032] Figure 6 This is an evaluation of the bleeding volume and hemostasis time of the rat tail amputation injury model according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below with reference to specific examples, which, however, are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0034] Unless otherwise specified, the reagents and materials used in the following examples were commercially available.

[0035] The kaolin nanotubes (EK), graphene oxide (GO), kaolin nanotube-grafted graphene oxide (EGO-EK), and chitosan (CS) solutions used in the following examples were prepared by the following method:

[0036] (1) Preparation of kaolin nanotubes (EK)

[0037] First, kaolin was sieved through a 100-mesh sieve and set aside. 10 g of 100-mesh kaolin was placed in a mixture of 100 mL of dimethyl sulfoxide and 9 mL of distilled water, stirred at 60°C for 12 h, filtered, and dried at 60°C for 24 h. The resulting kaolin-DMSO complex was dispersed in a sealed conical flask containing methanol and sonicated for 4 h. The kaolin-CH3OH complex was then centrifuged to obtain a wet sample. The wet kaolin-CH3OH complex was then dispersed in 50 mL of a 1 mol / L hexadecyltrimethylammonium chloride solution in methanol and stirred vigorously at room temperature for 12 h. The sample was then transferred to a polytetrafluoroethylene-lined reactor and reacted at 150°C for 12 h. After cooling, the mixture was centrifuged and washed several times with ethanol and distilled water. The mixture was then dried at 100°C to obtain dry kaolin nanotubes.

[0038] (2) Preparation of exfoliated graphene oxide (GO)

[0039] Add 6g of graphite powder to a 500mL flask containing concentrated sulfuric acid. Phosphorus pentoxide and potassium permanganate are then added sequentially while stirring. Place the flask in an 80°C waterbath and react for 4 hours. Filter and dry to obtain graphite oxide. Add graphite oxide to 240mL of concentrated sulfuric acid, followed by potassium dichromate. After reacting at 35°C for 2 hours, transfer the mixture to a container of crushed ice and add a 30% H₂O₂ solution dropwise. Successful oxidation is indicated by a color change from dark brown to bright yellow. Centrifuge to pH 7 and dry at 30°C to obtain graphene oxide. Weigh 0.3g of graphene oxide powder into a beaker containing 100mL of ultrapure water and sonicate for 4 hours to obtain a 0.3% exfoliated graphene oxide solution.

[0040] (3) Preparation of kaolin nanotube-grafted graphene oxide (EGO-EK)

[0041] The prepared exfoliated graphene oxide solution was transferred to a round-bottom flask, and then γ-glycidyloxypropyltrimethoxysilane (coupling agent KH560) was added at a mass ratio of 1:4 to the exfoliated graphene oxide, and then reacted at 60°C for 8h to obtain coupling agent-grafted graphene oxide (EGO).

[0042] Kaolin nanotubes were weighed at a mass ratio of 1:1 to exfoliated graphene oxide and fully dispersed in the solution. The mixture was vigorously stirred and reacted at 80°C for 3 hours, and then freeze-dried to obtain kaolin nanotube-grafted graphene oxide (EGO-EK).

[0043] (4) Preparation of chitosan (CS) solution

[0044] Weigh MW = 50000 2g of chitosan was dissolved in 2% dilute acetic acid, stirred at 300r / min at room temperature for 2h, and allowed to stand for 12h to fully dissolve to obtain a chitosan solution with a concentration of 1%. The pH of the chitosan solution was adjusted to 6.5-7 for use.

[0045] Example 1

[0046] This embodiment provides an antibacterial and hemostatic material CS, and the specific preparation method is as follows:

[0047] Add the crosslinking agent EDC and the catalyst NHS in equal weight ratio to the 1% CS solution, wherein the amount of EDC or NHS added is 0.2% of the weight of CS, and stir at 50°C for 30 minutes to obtain a uniform suspension.

[0048] The suspension was then poured into a mold, placed at 4°C for 12 h to eliminate bubbles, and then freeze-dried for 36 h to obtain a sponge scaffold.

[0049] Example 2

[0050] This embodiment provides an antibacterial and hemostatic composite material CS / EGO-EK, and the specific preparation method is as follows:

[0051] Weigh EGO-EK according to the mass ratio of CS:EGO-EK=5:1, dissolve it in 1% CS solution, and stir at 50℃ for 30 minutes to fully dissolve it;

[0052] Then, add the crosslinking agent EDC and the catalyst NHS in equal weight ratio, wherein the amount of EDC or NHS added is 0.2% of the weight of CS, and stir the reaction for 30 minutes to obtain a uniform suspension;

[0053] The suspension was then poured into a mold, placed at 4°C for 12 h to eliminate bubbles, and then freeze-dried for 36 h to obtain a sponge scaffold.

[0054] Example 3

[0055] This embodiment provides an antibacterial and hemostatic composite material CS / EGO-EK, and the specific preparation method is as follows:

[0056] Weigh EGO-EK according to the mass ratio of CS:EGO-EK=5:2, dissolve it in 1% CS solution, and stir at 50℃ for 30 minutes to fully dissolve it;

[0057] Then, add the crosslinking agent EDC and the catalyst NHS in equal weight ratio, wherein the amount of EDC or NHS added is 0.2% of the weight of CS, and stir the reaction for 30 minutes to obtain a uniform suspension;

[0058] The suspension was then poured into a mold, placed at 4°C for 12 h to eliminate bubbles, and then freeze-dried for 36 h to obtain a sponge scaffold.

[0059] Example 4

[0060] This embodiment provides an antibacterial and hemostatic composite material CS / EGO-EK, and the specific preparation method is as follows:

[0061] Weigh EGO-EK according to the mass ratio of CS:EGO-EK=5:3, dissolve it in 1% CS solution, and stir at 50℃ for 30 minutes to fully dissolve it;

[0062] Then, add the crosslinking agent EDC and the catalyst NHS in equal weight ratio, wherein the amount of EDC or NHS added is 0.2% of the weight of CS, and stir the reaction for 30 minutes to obtain a uniform suspension;

[0063] The suspension was then poured into a mold, placed at 4°C for 12 h to eliminate bubbles, and then freeze-dried for 36 h to obtain a sponge scaffold.

[0064] Example 5

[0065] This embodiment provides an antibacterial and hemostatic composite material CS / GO, the specific preparation method of which is as follows:

[0066] Weigh GO according to the mass ratio of CS:EGO-EK=5:2, dissolve it in 1% CS solution, and stir at 50℃ for 30min to fully dissolve it;

[0067] Then, add the crosslinking agent EDC and the catalyst NHS in equal weight ratio, wherein the amount of EDC or NHS added is 0.2% of the weight of CS, and stir the reaction for 30 minutes to obtain a uniform suspension;

[0068] The suspension was then poured into a mold, placed at 4°C for 12 h to eliminate bubbles, and then freeze-dried for 36 h to obtain a sponge scaffold.

[0069] Testing and Analysis:

[0070] 1. SEM structural analysis of sponge scaffolds

[0071] Testing method: 300 μL of the pre-freezing suspension was placed in a 48-well plate and freeze-dried at -80°C to obtain a freeze-dried composite sponge. The freeze-dried composite sponge was then attached to a copper plate using carbon conductive adhesive. Gold was sprayed onto the surface for 30 seconds, and the surface morphology was observed using a scanning electron microscope (SEM). Testing conditions were 5 kV electron beam. Statistical analysis of the pore size of the composite sponge was performed using Image software.

[0072] Test samples: CS of Example 1, CS / EGO-EK of Examples 2-4.

[0073] The results are as follows Figure 1 As shown in the figure, the freeze-dried composite sponge has an interconnected macroporous structure with a pore size of about 50 μm. At the same time, as the EGO-EK content increases, the pores gradually decrease and the structure becomes denser, which is mainly attributed to the increase in cross-linking degree and the effect of freeze-drying.

[0074] 2. Swelling and water absorption performance test

[0075] Test method: Weigh the sponge scaffold sample using a balance, recording the weight as M0. Place the sample in PBS and allow it to swell for 0.5, 1, 2, 3, 4, 5, and 6 hours. Quickly remove the surface moisture with filter paper and weigh the sample, recording the mass as Mw. The sample water absorption (X) is calculated using the following formula:

[0076] X(%)=(Mw-M0) / M0×100%

[0077] Test samples: CS of Example 1, CS / EGO-EK of Examples 2-4.

[0078] Results: Combined Figure 1 It can be seen that the composite material is rich in porous network structure and has good water absorption capacity, which helps to better absorb blood and wound exudate, promote rapid hemostasis of wounds, and thus prevent bacterial infection. Figure 2 As shown, all composite materials exhibit excellent water absorption performance, swell rapidly within 1 hour after absorbing water, and basically complete 80% of water absorption within 1 hour. Then, after absorbing water and swelling for 5 hours, the water absorption rate reaches a balanced state. Among them, the composite material CS / EGO-EK of Example 3 5:2 It has the best water absorption performance, with the water absorption rate reaching 1280% after swelling for 6 hours; it can fully meet the requirements of rapid expansion to fill the wound cavity.

[0079] 3. Compression performance

[0080] Testing Method: 400 μL of the pre-lyophilized suspension was placed in a 48-well plate and dried in a freeze dryer to form a cylindrical sponge dressing with a diameter of 10 mm and a height of 7 mm. After being placed in a constant humidity environment overnight, the sponge dressing was compressed to 80% of its original height at a rate of 5 mm / min using a universal testing machine. The relationship between stress (MPa) and strain (%) was recorded to examine the material's longitudinal compressive strength.

[0081] Test samples: CS of Example 1, CS / EGO-EK of Examples 2-4.

[0082] Results: In order to reduce the discomfort and pain of patients, hemostatic materials need to have good compression properties when used on wounds. Therefore, the compression strain-stress curve is used to evaluate the mechanical strength of hemostatic materials. Figure 3 As shown in the figure, after adding EGO-EK, the compressive stress increases. When the sponge is 80% deformed, the compressive stress of the hemostatic materials prepared by adding EGO-EK in Examples 2-4 is all greater than 600Kpa. 5:2 The results show that the introduction of an appropriate amount of EGO-EK into the hemostatic material of the present invention can improve the compressive strength. This shows that the composite hemostatic material of the present invention has good mechanical properties and a certain supporting capacity, and has high application value as a wound dressing.

[0083] 4. In vitro antibacterial performance test

[0084] Test Method: Escherichia coli and Staphylococcus aureus were revived and cultured to the logarithmic growth phase. The cells were centrifuged, harvested, and resuspended in saline to a final concentration of 1 × 108 CFU / mL. 500 μL of the corresponding suspension was added to a 24-well plate and cured under UV light to form a gel. 500 μL of saline was added to the control group. Subsequently, 100 μL of the diluted bacterial suspension and 1 mL of sterile saline were added to each well. The cells were incubated at 37°C for 24 hours. After serial dilution, the cells were spread onto LB agar plates and counted.

[0085] Test samples: CS of Example 1, CS / EGO-EK of Example 3, and CS / GO of Example 5.

[0086] Result description: Figure 4 CS, CS / GO are shown in 、 CS / EGO-EK 、 CS / GO 、 +NIR, CS / EGO-EK+NIR in vitro antibacterial test results, where the NIR group used a power of 1.5W / cm 2 808nm near-infrared light irradiation.

[0087] It can be seen that graphene oxide sheets themselves have excellent antibacterial effects, mainly due to the following reasons: 1) Graphene oxide contains a large number of oxygen-containing groups, such as hydroxyl, carboxyl, and carbonyl groups. These groups can form hydrogen bonds with the sugars or proteins that make up the cell wall. Graphene oxide then wraps the cells to isolate them from the nutrient solution, causing them to die from lack of nutrients; 2) Graphene oxide can adsorb on bacteria, and its sharp edges can damage the cell membrane, causing the bacteria to break and die; 3) Graphene oxide can change the oxygen partial pressure within the bacteria, causing the substances within the bacteria to be oxidized, destroying the internal composition of the bacteria and leading to bacterial death. The introduction of EGO-EK has a certain synergistic antibacterial effect. At the same time, the photothermal conversion properties of graphene oxide under 808nm near-infrared laser irradiation, combined with near-infrared irradiation, can cause excessive heat to be generated inside the bacteria, further improving the sterilization rate.

[0088] 5. In vitro hemostatic performance

[0089] Test method: The hemostatic potential of the material was evaluated by a whole blood coagulation experiment. Specifically, the sponge scaffold sample was placed in a 37°C culture dish, and 100 μL of blood (containing 3.8wt% anticoagulant sodium citrate 1:9) and 20 μL of CaCl2 (0.2mol / L) solution were divided into the sponge. The sample was incubated at 37°C for 5 minutes, then added to 25mL of distilled water, gently shaken, and allowed to stand for 5 minutes. The absorbance value of each sample was then measured at 545nm using an ultraviolet spectrophotometer. The blank control group was composed of 200 μL of blood added to 25mL of distilled water. The formula for calculating the coagulation index (BCI) is: BCI (%) = [OD sample / OD control ]×100%, where OD sample is the sample absorbance value, OD control is the absorbance value of the blank group.

[0090] Test samples: CS of Example 1, CS / EGO-EK of Example 3, and CS / GO of Example 5.

[0091] Results show that the whole blood coagulation index reflects the coagulation effect of the material. The lower the coagulation index, the better the coagulation effect. Figure 5As shown, the coagulation index of the hemostatic material with the addition of EGO-EK is significantly reduced, indicating that the introduction of kaolin nanotubes greatly enhances the coagulation ability of the material. At the same time, after deionized water is poured into the culture dish, Example 3 overflows the least red blood cells. The material CS / EGO-EK of these Example 3 has excellent coagulation ability, which mainly depends on its chemical composition and spatial structure. The interconnected microporous structure of the hemostatic sponge is combined with chitosan to significantly improve the blood absorption rate and red blood cell aggregation rate of the material. In addition, kaolin nanotubes are a kind of aqueous aluminosilicate mineral, which further activates the human coagulation cascade by activating coagulation factor XII (FXII). The two materials cooperate with each other to further enhance the hemostatic ability.

[0092] 6. In vivo hemostatic ability

[0093] Test method: Anesthetize rats with 3% (w / v) sodium pentobarbital (intraperitoneal injection, 30 mg / kg) for 3 minutes. After successful anesthesia, the rats were fixed on the operating table in supine position. Disinfect the rat's tail with 75% medicinal alcohol and cut it in the middle with surgical scissors. After 10 seconds of free bleeding, wipe off the flowing blood with sterile gauze, and then stick the composite material sponge to the wound. Press the sampling sponge lightly with your hand and start timing from this starting point. Observe the wound every 30 seconds until there is no bleeding within 30 seconds after removing the hemostatic material. Record the hemostasis time, weigh the sample after hemostasis, and calculate the amount of bleeding. The gelatin sponge was used as the control group, and the untreated group was used as the blank control. Blood loss (m BL ) is calculated as follows: BL =m2-m1, where m1 and m2 are the mass of the sample before and after hemostasis, respectively, in g.

[0094] Test samples: CS of Example 1, CS / EGO-EK of Example 3, and CS / GO of Example 5.

[0095] Results: First, the hemostatic effect of the material was evaluated using a rat tail amputation model. Figure 6 (A) shows photographs of bleeding on filter paper after hemostasis using different hemostatic materials. Among the experimental groups, CS / EGO-EK of Example 3 had the shortest hemostatic time and the least amount of bleeding, demonstrating the best hemostatic performance.

[0096] There are several reasons that can explain the above results, including: a) the porous network structure gives the hemostatic material excellent blood absorption ability and concentrates coagulation factors to capture red blood cells and platelets, thereby accelerating the coagulation process; b) when kaolin nanotubes come into contact with blood, they quickly absorb smaller water molecules in the blood, activate coagulation factors, and activate the body's coagulation cascade reaction; c) positively charged chitosan comes into contact with negatively charged red blood cells, causing red blood cells to aggregate and adhere to the wound.

[0097] In summary, the antibacterial and hemostatic composite material of the present invention, by introducing EGO-EK into chitosan, improves its swelling and water absorption properties, compressibility, antibacterial properties, and in vitro and in vivo hemostatic performance. Furthermore, photothermal effects can be utilized to further enhance its antibacterial properties. The composite material of the present invention exhibits excellent hemostatic effects, rapid expansion to fill wound cavities, suitable tissue adhesion, superior biocompatibility, and good antibacterial properties, promoting tissue healing.

[0098] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing an antibacterial and hemostatic composite material, characterized in that: Including steps: S1: First, exfoliated graphene oxide is reacted with KH560 at 60°C to obtain coupled grafted graphene oxide (EGO); then, kaolin nanotubes are reacted with the EGO at 80°C under vigorous stirring to obtain kaolin nanotube-coupled grafted graphene oxide (EGO-EK); S2 uses a cross-linking agent and a catalyst to react the chitosan solution with EGO-EK to obtain a uniform suspension, which is then freeze-dried to obtain the antibacterial and hemostatic composite material; According to the mass ratio, in step S1, the exfoliated graphene oxide: KH560 = 1:4; kaolin nanotubes: EGO = 1:1; The exfoliated graphene oxide is prepared by the following method: mixing graphite powder with concentrated sulfuric acid, then sequentially adding phosphorus pentoxide and potassium permanganate, and then reacting in a water bath at 80° C. to obtain graphite oxide; Then, the obtained graphite oxide was mixed with concentrated sulfuric acid, and potassium dichromate was added, and the mixture was reacted at 35°C. After the reaction was completed, a 30% H2O2 solution was added dropwise in an ice bath to obtain graphene oxide. Finally, ultrasonic exfoliation is performed to obtain the exfoliated graphene oxide; The kaolin nanotubes are prepared by the following method: Kaolin, dimethyl sulfoxide, and distilled water are mixed and stirred at 60° C. for reaction, and filtered and dried to obtain a kaolin-DMSO complex; the obtained dry kaolin-DMSO complex is dispersed in methanol, sealed and ultrasonicated, and then centrifuged to obtain a kaolin-CH3OH complex wet sample; the kaolin-CH3OH wet sample is then dispersed in a hexadecyltrimethylammonium chloride methanol solution, vigorously stirred at room temperature for 10 to 14 hours, and finally transferred to a reactor, reacted at 140 to 160° C. for 10 to 14 hours, and after cooling, centrifuged, washed, and dried to obtain the kaolin nanotubes; The kaolin: dimethyl sulfoxide: distilled water: hexadecyltrimethylammonium chloride methanol solution = 10 g: 100 mL: 9 mL: 50 mL, and the concentration of the hexadecyltrimethylammonium chloride methanol solution is 1 mol / L; In step S2, the mass ratio of chitosan: EGO-EK is 5:1-3; In step S2, the cross-linking agent is EDC and the catalyst is NHS; In step S2, the chitosan M W =50000, chitosan solution pH=6.5-7, concentration is 1wt%.

2. The preparation method according to claim 1, characterized in that The kaolin particle size is ≤150 μm.

3. The antibacterial and hemostatic composite material prepared according to the preparation method according to any one of claims 1-2.

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