Self-healing rapid hemostatic liquid bandage gel dressing and method of making same

Abstract

The application discloses a self-healing quick hemostatic liquid bandage gel dressing and a preparation method thereof. The gel dressing is a two-component spray gel composed of independently encapsulated first and second precursor solutions. The first precursor solution contains catechol-modified sodium alginate and tranexamic acid, and the second precursor solution contains oxidized sodium alginate and calcium chloride. The application realizes equal-volume spray mixing by single-handed pressing through a double-cavity spray bottle. The self-healing hydrogel is formed on the surface of a wound through reversible Schiff base bonds and calcium ion coordination bonds. The self-healing hydrogel is quickly formed in 10-60 seconds, and the self-healing recovery rate is over 90% within 30 seconds. The hemostatic time of mouse liver puncture is as short as 15-30 seconds, and the self-healing hydrogel can be dissolved and removed by a sodium citrate solution within 1 minute.

Description

Technical Field

[0001] This invention relates to the field of medical hemostatic materials technology, and in particular to a self-healing, rapid-acting hemostatic body bandage gel dressing and its preparation method. Background Technology

[0002] Currently, commonly used hemostatic products in clinical practice include hemostatic gauze, zeolite powder, chitosan hemostatic powder, gelatin sponge, and various liquid bandages. Among these, liquid bandages have attracted widespread attention due to their ability to conform to irregular wound surfaces, form a protective film, and are easy to use. Existing technologies have disclosed several sprayable gel dressings or liquid hemostatic materials, such as hemostatic gels based on natural or synthetic polymers like alginate, polyvinyl alcohol, and chitosan.

[0003] First, traditional hemostatic gauze or powder is difficult to adequately cover and adhere to deep, narrow, or irregularly shaped wounds, and removal can easily cause secondary damage. Many existing spray-on liquid bandages are typically single-component solvent-based film-forming agents, with long film-forming times (several minutes), and the resulting film is brittle and has poor adhesion, easily cracking and detaching at joints, leading to secondary bleeding. Second, although some two-component in-situ gelling hemostatic gels have been reported, most require pre-mixing the two components in vitro before application to the wound, a cumbersome procedure unsuitable for single-handed operation in emergencies; alternatively, using a dual-syringe syringe to squeeze out the components and manually apply them results in poor mixing uniformity, uncontrollable gel-forming speed, and easy washing away by blood before complete mixing. Third, existing self-healing hydrogels typically require long self-healing times (minutes or more) or rely on specific external stimuli (such as temperature or pH changes), making it difficult to meet the requirements for immediate mechanical recovery in rapid hemostasis scenarios. Fourth, many hemostatic materials are difficult to separate from the tissue surface after wound healing; forcibly removing them can damage newly formed granulation tissue.

[0004] Therefore, in response to the problems mentioned above, this invention proposes a self-healing, rapid hemostatic body bandage gel dressing and its preparation method. Summary of the Invention

[0005] To overcome the problems of existing hemostatic dressings being prone to breakage and failure under dynamic wound conditions, having poor ease of operation, lacking self-healing ability, and being difficult to remove after hemostasis, this invention proposes a self-healing, rapid hemostatic body bandage gel dressing and its preparation method.

[0006] The technical solution of the present invention is: a self-healing, fast-acting, hemostatic bandage gel dressing, wherein the gel dressing is a two-component spray gel, comprising an independently packaged first precursor solution and a second precursor solution, wherein the volume ratio of the first precursor solution to the second precursor solution is 1:1;

[0007] The first precursor solution comprises, by weight-volume percentage (w / v), 2-8% catechol-modified sodium alginate, 0.5-2% tranexamic acid, 0.1-1% antimicrobial peptide (ε-polylysine or nisin), with the balance being phosphate buffer at pH 7.4.

[0008] The second precursor solution comprises, by weight-volume percentage (w / v), 1-5% sodium alginate, 0.1-0.5% calcium chloride, 0.01-0.1% recombinant human thrombin, and the balance being deionized water;

[0009] The gel dressing is operated by one hand by pressing and spraying through a dual-chamber spray bottle. The two precursor solutions are mixed in equal volumes at the moment of spraying and form a self-healing hydrogel on the wound surface within 10-60 seconds.

[0010] The self-healing property originates from the reversible Schiff base bond formed between the amino group of the dopamine residue in catechol-modified sodium alginate and the aldehyde group in oxidized sodium alginate, as well as the dual dynamic crosslinking of the coordination bond formed between calcium ions and the carboxyl group on the sodium alginate chain.

[0011] Preferably, the degree of substitution of the catechol-modified sodium alginate is 15-35%, and its preparation method is as follows: sodium alginate is dissolved in 0.1M MES buffer at pH 5.5, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide are added to activate the carboxyl group, then dopamine hydrochloride is added, and the reaction is carried out at room temperature in the dark for 12-24 hours, followed by dialyzing and lyophilization.

[0012] Preferably, the oxidation degree of the oxidized sodium alginate is 40-60%, and its preparation method includes: dissolving sodium alginate in deionized water, adding sodium periodate, reacting in the dark for 2-6 hours, adding ethylene glycol to terminate the reaction, and dialysis and freeze-drying to obtain the product.

[0013] Preferably, the dual-chamber spray bottle includes a first liquid storage chamber, a second liquid storage chamber, a press pump head, and a mixing nozzle. The first liquid storage chamber is used to contain a first precursor solution, and the second liquid storage chamber is used to contain a second precursor solution. When the pump head is pressed, the solutions in the two chambers enter the mixing nozzle through independent channels in equal volume proportions, and after merging at the nozzle, they are sprayed out in the form of mist or droplets.

[0014] This invention proposes a method for preparing a self-healing, rapid-acting hemostatic body bandage gel dressing, comprising the following steps:

[0015] S1. Sodium alginate was dissolved in 0.1M MES buffer at pH 5.5 to prepare a 1-3% (w / v) solution. 1-Ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added at a molar ratio of 1:0.5-1 relative to the carboxyl groups of sodium alginate to activate the carboxyl groups. After activation for 30 minutes, dopamine hydrochloride was added at a molar ratio of 1:0.5-1.5 relative to the carboxyl groups of sodium alginate. The pH was adjusted to 5.5, and the reaction was carried out at room temperature in the dark for 24 hours. After the reaction was completed, the solution was dialyzed with deionized water for 3 days and then lyophilized to obtain catechol-modified sodium alginate.

[0016] S2, dissolve sodium alginate in deionized water to prepare a 1-2% (w / v) solution, add sodium periodate, the molar ratio of sodium periodate to sodium alginate sugar units is 1:0.2-0.5, react in the dark for 4 hours, add ethylene glycol to terminate the reaction, dialyze with deionized water for 2 days, and freeze dry to obtain oxidized sodium alginate.

[0017] S3, the obtained catechol-modified sodium alginate, tranexamic acid and antimicrobial peptide were placed in phosphate buffer at pH 7.4 to make the final concentration of catechol-modified sodium alginate 2-8% (w / v) and the final concentration of tranexamic acid 0.5-2% (w / v). The solution was then sterile filtered through a 0.22 μm filter membrane to obtain the first precursor solution.

[0018] S4, the obtained sodium oxidized alginate, calcium chloride and recombinant human thrombin are dissolved in deionized water to make the final concentration of sodium oxidized alginate 1-5% (w / v) and the final concentration of calcium chloride 0.1-0.5% (w / v). The solution is then sterile filtered through a 0.22μm filter membrane to obtain the second precursor solution.

[0019] S5, the first precursor solution and the second precursor solution are respectively filled into the first and second storage chambers of the dual-chamber spray bottle and sealed.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention constructs a dual dynamic cross-linking network by simultaneously introducing reversible Schiff base bonds between catechol-modified sodium alginate and oxidized sodium alginate, and coordination bonds between calcium ions and carboxyl groups on the alginate chain. This allows the gel dressing to recover more than 90% of its storage modulus within 30 seconds without external stimulation after being damaged by external force. This solves the problems of slow healing, poor mechanical strength, and inability to meet the immediate repair needs of dynamic bleeding wounds in existing self-healing hydrogels, and significantly improves the success rate of hemostasis.

[0022] 2. This invention uses a dual-chamber spray bottle to independently package the first and second precursor solutions. With a single hand press, equal volumes can be instantly mixed and uniformly covered on the wound surface in a mist. The gel formation time is only 10-60 seconds, and the operation time is less than 3 seconds. This solves the problems of uneven mixing, cumbersome operation, and easy washing away by blood caused by the need for pre-mixing or manual application of existing two-component hemostatic gels. It is especially suitable for pre-hospital emergency care and rapid treatment of irregular wounds.

[0023] 3. The present invention adds tranexamic acid to the first precursor solution, which produces a synergistic hemostatic effect with calcium chloride in the second precursor solution. In the mouse liver puncture model, the hemostasis time is as short as 15-30 seconds, which solves the problems of slow hemostasis and ineffectiveness of existing liquid bandages for active bleeding.

[0024] 4. The gel dressing formed by this invention can be completely dissolved and removed within 1 minute by a 10% sodium citrate solution. It utilizes the competitive chelation of calcium ions by citrate ions to break the coordination bonds, while the Schiff base bonds are hydrolyzed under acidic conditions. This solves the problem that existing hemostatic materials are difficult to separate from the tissue surface after healing, and that forced removal will damage the newly formed granulation tissue, thus achieving painless and damage-free removal. Attached Figure Description

[0025] Figure 1 The diagram shown illustrates the preparation process of this invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, but 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.

[0027] This invention provides an embodiment:

[0028] This invention is a two-component spray gel, comprising a separately packaged first precursor solution and a second precursor solution, used in a 1:1 volume ratio. The first precursor solution contains 2-8% (w / v) catechol-modified sodium alginate, 0.5-2% tranexamic acid, and 0.1-1% antimicrobial peptides (ε-polylysine or nisin), with the balance being phosphate buffer at pH 7.4. The second precursor solution contains 1-5% (w / v) oxidized sodium alginate, 0.1-0.5% calcium chloride, and 0.01-0.1% recombinant human thrombin, with the balance being deionized water. This gel dressing is operated with a single-handed press-spray via a dual-chamber spray bottle. The two precursor solutions mix in equal volumes upon spraying, forming a self-healing hydrogel on the wound surface within 10-60 seconds.

[0029] This invention provides Embodiment 1:

[0030] Please see Figure 1 Preparation method:

[0031] S1. Dissolve 10 g of sodium alginate in 1000 mL of 0.1 M MES buffer (pH 5.5) to prepare a 1% (w / v) solution. Add 1.92 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, equivalent to 0.8 times the molar ratio of sodium alginate carboxyl groups) and 1.15 g of N-hydroxysuccinimide (NHS, equivalent to 0.5 times the molar ratio of sodium alginate carboxyl groups), and activate at room temperature with stirring for 30 minutes. Then add 2.2 g of dopamine hydrochloride (equivalent to 0.6 times the molar ratio of sodium alginate carboxyl groups), adjust the pH to 5.5, and react at room temperature in the dark for 24 hours. After the reaction is complete, put the reaction solution into a dialysis bag with a molecular weight cutoff of 8000-14000 Da, dialyze in deionized water for 3 days (changing the water 4 times a day), and freeze-dry to obtain catechol-modified sodium alginate. The amount of dopamine grafted was determined by ultraviolet spectrophotometry at 280 nm, and the degree of substitution was calculated to be 25.6% (the degree of substitution is defined as the number of dopamine grafted per 100 sodium alginate sugar units).

[0032] S2, dissolve 10g of sodium alginate in 1000mL of deionized water to prepare a 1% (w / v) solution. Add 5.35g of sodium periodate and react in the dark for 4 hours. Add 2mL of ethylene glycol to terminate the reaction and continue stirring for 30 minutes. Dialyze the reaction solution in deionized water for 2 days (molecular weight cutoff as above), and lyophilize to obtain oxidized sodium alginate. Determine the aldehyde content using the hydroxylamine hydrochloride titration method, and calculate the oxidation degree to be 48.2%.

[0033] S3, weigh 4g of the obtained catechol-modified sodium alginate and 1g of tranexamic acid, dissolve them in 100mL of pH 7.4 phosphate buffer to make the final concentration of catechol-modified sodium alginate 4% (w / v) and the final concentration of tranexamic acid 1% (w / v). Stir well and filter aseptically through a 0.22μm polyethersulfone membrane to obtain the first precursor solution.

[0034] S4. Weigh 2g of the obtained sodium alginate oxide and 0.2g of calcium chloride, dissolve them in 100mL of deionized water to make the final concentration of sodium alginate oxide 2% (w / v) and the final concentration of calcium chloride 0.2% (w / v). Stir well and filter aseptically through a 0.22μm filter membrane to obtain the second precursor solution.

[0035] S5, the first precursor solution and the second precursor solution are respectively filled into the first and second storage chambers of the 5mL dual-chamber spray bottle, with 3mL filled into each chamber, and then sealed.

[0036] The test results are shown in Table 1:

[0037] Table 1 Test results of Example 1

[0038] Testing items Test Results Notes / Testing Method gelation time Average 28 seconds (range 25-33 seconds) Glass rod penetration test after spraying at 25℃, n=5 Initial storage modulus G' 680 Pa Rheometer, 1% strain, 1 Hz, 25℃ G' at 1% strain after failure at 500% strain and recovery for 30 seconds 620 Pa Recovery rate: 91.2% G' at 1% strain after failure at 500% strain and recovery for 60 seconds 665 Pa Recovery rate: 97.8% G' at 1% strain after failure at 500% strain and recovery for 300 seconds 680 Pa Fully restored to initial value Self-healing cycles ≥3 sessions, with a recovery rate >90% each time. Strain Cyclic Testing Time to stop bleeding in mouse liver puncture 22.4 ± 3.1 seconds 18G needle puncture, spray once, n=8 10% sodium citrate solution removal time 48±6 seconds Droplets are added to the gel surface; complete dissolution time, n=8 relative survival rate of L929 cells 95.8% MTT method, ISO 10993-5 Skin irritation index 0 New Zealand rabbit, GB / T 16886.10-2017 Gel appearance Translucent, uniform gel film After spray mixing

[0039] (1) Press the spray bottle filled above once at 25°C (about 0.2 mL of total liquid) and spray it into the glass petri dish. Start timing at the same time. Gently touch the droplet with a glass rod. Record the gelation time when the droplet stops flowing and the surface becomes elastic. Repeat 5 times. The average gelation time is 28 seconds (range 25-33 seconds).

[0040] (2) Strain cycling tests were performed using a rotational rheometer (20 mm diameter plate, 500 μm gap). The gel sprayed in Example 1 was first deposited in a petri dish to form a gel sheet approximately 1 mm thick. A circular sample with a diameter of 20 mm was then placed on the rheometer platform. Test conditions: oscillation frequency 1 Hz, 25 °C. In the first stage, a 1% strain (linear viscoelastic region) was applied for 60 seconds, and the storage modulus G' was measured to be 680 Pa. In the second stage, a 500% strain (destructive strain) was applied for 60 seconds, causing the gel structure to break down and G' to drop to 12 Pa. In the third stage, the strain was restored to 1% for 300 seconds, and the recovery of G' was observed. The results showed that after restoring to 1% strain, G' recovered to 620 Pa (recovery rate 91.2%) at 30 seconds, 665 Pa (recovery rate 97.8%) at 60 seconds, and completely recovered to the initial value at 300 seconds. The above cycle was repeated three times, with each recovery rate exceeding 90%, demonstrating the excellent rapid self-healing properties of the gel.

[0041] (3) A mouse liver puncture hemorrhage model was used. Male Kunming mice weighing 25-30g were selected, anesthetized, and their livers were exposed by abdominal surgery. A 3mm deep puncture wound was created in the left lobe of the liver using an 18G needle, allowing blood to flow out naturally. The natural hemostasis time was measured to be 187±32 seconds in the preliminary experiment. The spray from Example 1 was applied to the wound, and the spray was applied once (about 0.2mL) to cover the wound. The time from the start of spraying to the complete cessation of bleeding (no fresh blood seepage) was recorded as the hemostasis time. A total of 8 mice were tested, and the average hemostasis time was 22.4±3.1 seconds. At the same time, the adhesion between the gel membrane and the tissue after hemostasis was observed. The gel membrane adhered tightly to the wound and did not fall off when gently pulled.

[0042] (4) Thirty minutes after hemostasis, 10% (w / v) sodium citrate solution (pH 7.0) was added to the gel surface using a dropper to cover the gel, and the time for complete dissolution and disappearance of the gel was recorded. The average dissolution and removal time for the 8 mice was 48±6 seconds. No obvious secondary bleeding was observed on the wound surface after removal, and the tissue surface was smooth with no gel residue.

[0043] (5) MTT assay was performed using L929 mouse fibroblasts according to ISO 10993-5 standard. The two precursor solutions of the gel dressing from Example 1 were mixed in a 1:1 ratio, gelled in a culture dish, and then soaked in cell culture medium (DMEM and 10% fetal bovine serum) at 37°C for 24 hours to obtain the extract. L929 cells were cultured at 1×10⁶ cells per well. 4 Cells were seeded into 96-well plates and cultured for 24 hours. The original culture medium was discarded, and 100 μL of extraction buffer was added. Cultured for another 24 hours. The control group received fresh culture medium. Then, 20 μL of MTT solution (5 mg / mL) was added to each well, and the cells were cultured for 4 hours. The supernatant was discarded, and 150 μL of DMSO was added to dissolve the formazan. The absorbance at 570 nm was measured using a microplate reader. Relative cell viability was calculated as (OD value of experimental group / OD value of control group) × 100%. The results showed that the OD value of the experimental group was 0.68 ± 0.05, and that of the control group was 0.71 ± 0.04, with a cell viability of 95.8%, indicating that the gel was non-cytotoxic.

[0044] (6) Referring to GB / T 16886.10-2017, the hair on the back of New Zealand rabbits was removed, and the gel dressing of Example 1 (a mixture of two precursor solutions) and physiological saline (control) were applied respectively. The dressings were covered for 4 hours, and the rabbits were observed at 1, 24 and 48 hours after removal. No irritation reactions such as erythema or edema were observed, and the irritation index was 0, which was determined to be non-irritating.

[0045] This invention provides Embodiment 2:

[0046] This embodiment is based on Example 1, with the addition of the antimicrobial peptide ε-polylysine to the first precursor solution at a final concentration of 0.5% (w / v); and the addition of recombinant human thrombin to the second precursor solution at a final concentration of 0.05% (w / v). Other components and preparation methods are the same as in Example 1.

[0047] The first precursor solution was prepared as follows: 4g of catechol-modified sodium alginate (degree of substitution 25.6%), 1g of tranexamic acid, and 0.5g of ε-polylysine were weighed and dissolved in 100mL of pH 7.4 phosphate buffer solution, and then filtered for sterilization.

[0048] The second precursor solution was prepared as follows: Weigh 2g of oxidized sodium alginate (oxidation degree 48.2%), 0.2g of calcium chloride, and 5mg of recombinant human thrombin (activity ≥1000IU / mg), dissolve in 100mL of deionized water, and filter through a 0.22μm filter membrane (the thrombin solution needs to be filtered separately before being added to the filtered oxidized sodium alginate / calcium chloride solution to avoid thrombin loss due to filtration adsorption). The remaining filling steps are the same as in Example 1.

[0049] The test results are shown in Table 2:

[0050] Table 2 Test Results of Example 2

[0051] Testing items Results of Example 2 Notes / Testing Method gelation time Average 26 seconds (range 23-30 seconds) Glass rod penetration test after spraying at 25℃, n=5 Initial storage modulus G' 710Pa Rheometer, 1% strain, 1Hz, 25℃ G' (recovery rate) when the strain recovers to 1% after failure at 500% strain for 30 seconds. 648Pa (91.3%) Strain Cyclic Testing G' (recovery rate) when the strain recovers to 1% after failure at 500% strain for 60 seconds. 695Pa (97.9%) Strain Cyclic Testing Time to stop bleeding in mouse liver puncture 15.3 ± 2.5 seconds 18G needle puncture, spray once, n=8 Time for hemostasis by transverse section of the femoral artery in rats 15.3 ± 2.5 seconds Artery wall transversely cut at 1 / 3, n=8 10% sodium citrate solution removal time 46±5 seconds Droplets are added to the gel surface; complete dissolution time, n=8 Diameter of inhibition zone (Staphylococcus aureus ATCC 25923) 16.5±1.2mm Agar diffusion method: 20 μL of filter paper is mixed to form a gel solution. Diameter of inhibition zone (E. coli ATCC 25922) 13.8±0.9mm Agar diffusion method: 20 μL of filter paper is mixed to form a gel solution. hemolysis rate 2.1% Rabbit red blood cell suspension, 540 nm, negative control saline

[0052] (1) The average gelation time was 26 seconds, which was slightly faster than that of Example 1, but the impact was not significant.

[0053] (2) A rat femoral artery hemorrhage model (a more severe hemorrhage model) was used. SD rats (300-350g) were anesthetized, and the femoral artery was separated. One-third of the vessel wall was transversely cut with a scalpel to create jet-like bleeding. The rats were randomly divided into three groups: Group 1 was a blank control (gauze applied), Group 2 received the gel dressing from Example 1, and Group 3 received the gel dressing from Example 2. Each group consisted of 8 rats. The average natural hemostasis time in Group 1 was 245 seconds (due to the difficulty in stopping arterial bleeding spontaneously), in Group 2 it was 28.6±4.2 seconds, and in Group 3 it was 15.3±2.5 seconds. The hemostasis time in Group 3 was significantly shorter than that in Group 2 (p<0.01), indicating that the addition of recombinant human thrombin significantly enhanced the rapid hemostasis effect. Furthermore, in Group 3, the gel adhered firmly to the arterial rupture within 30 seconds after hemostasis, with no further bleeding.

[0054] (3) The antibacterial performance was tested using the inhibition zone method. Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 were respectively spread on MH agar plates. Sterile filter paper discs with a diameter of 8 mm were placed on the plate surface, and 20 μL of the mixture of Example 2 gel dressing (before gel formation) and Example 1 were added as controls. The mixtures were incubated at 37℃ for 24 hours, and the diameter of the inhibition zone was measured. Example 1 showed an inhibition zone of 0 mm against Staphylococcus aureus (no antibacterial effect) and no inhibition zone against Escherichia coli. Example 2 showed an inhibition zone diameter of 16.5 ± 1.2 mm against Staphylococcus aureus and 13.8 ± 0.9 mm against Escherichia coli, indicating that ε-polylysine endowed the gel with broad-spectrum antibacterial activity.

[0055] (4) Rheological tests were performed in the same manner as in Example 1. The results showed that the initial storage modulus of the gel in Example 2 was G' = 710 Pa. After 500% strain failure, it recovered to 1% strain. At 30 seconds, G' recovered to 648 Pa (recovery rate 91.3%), and at 60 seconds, it recovered to 695 Pa (97.9%), which was comparable to that in Example 1. This indicates that the addition of antimicrobial peptides and thrombin does not affect the self-healing properties.

[0056] (5) A hemolysis rate test was performed. A 2% red blood cell suspension was prepared from rabbit heart blood and mixed 1:1 with the gel extract from Example 2 (prepared according to the method in Example 1). The mixture was incubated at 37°C for 1 hour, and the absorbance of the supernatant at 540 nm was measured after centrifugation. The negative control was physiological saline, and the positive control was 0.1% Triton X-100. The hemolysis rate was calculated as: (sample absorbance - negative control absorbance) / (positive control absorbance - negative control absorbance) × 100%. The hemolysis rate was 2.1% (<5%), meeting the requirements for hemolysis in medical materials.

[0057] Comparative Example 1 provided by the present invention:

[0058] This comparative example is used to verify that the dual dynamic crosslinking system utilizing both reversible Schiff base bonds and calcium ion coordination bonds in this invention has a synergistic effect on rapid hemostasis, self-healing rate, and wound adhesion strength compared to a single crosslinking system containing only Schiff base bonds or only calcium ion coordination bonds, and the effect is far superior to that of a single system. The specific grouping is shown in Table 3:

[0059] Table 3 Experimental group design

[0060] Group First precursor solution (w / v) Second precursor solution (w / v) Crosslinking type Example 1 4% catechol-modified sodium alginate + 1% tranexamic acid 2% sodium alginate oxide + 0.2% calcium chloride <![CDATA[Schiff base + Ca 2+ Coordination]]> Comparison Group 1 4% catechol-modified sodium alginate + 1% tranexamic acid 2% Sodium Oxygenated Schiff bases only Comparison Group 2 4% Unmodified Sodium Alginate + 1% Tranexamic Acid 0.2% calcium chloride <![CDATA[Only Ca 2+ coordination (without dynamic covalent bonds)]]>

[0061] (1) In this experiment, the gelation time was determined by the glass rod probing method at room temperature (25℃). A total of five tests were conducted, and the average value was taken. The results are shown in Table 4:

[0062] Table 4 Results of gelation time determination

[0063] Group Average gelation time (seconds) Range (seconds) Example 1 28 25-33 Comparison Group 1 35 30-42 Comparison Group 2 >120 (still a flowing liquid after 60 seconds) Incomplete gelation

[0064] As shown in Table 4, only Ca 2+ The coordination group cannot form a stable gel in a short time because although ordinary sodium alginate and calcium ions can form an eggshell structure, the gelation speed is limited by the diffusion and uniformity of calcium ions. After spray mixing, the local cross-linking is loose and the flowability is high. In Example 1, due to the rapid formation of a pre-crosslinked network by the Schiff base and the further reinforcement by calcium ions, the gelation time is the shortest and the gel is uniform.

[0065] (2) The rheological strain cyclic test was performed under the same conditions as in Example 1, and the cycle was repeated 3 times. The results are shown in Table 5:

[0066] Table 5. Results of self-healing performance test

[0067] Group Example 1 Comparison Group 1 Comparison Group 2 Initial G'(Pa) 680 210 Unable to form a stable gel, not measured Recovery time is 30 seconds G'(Pa) after destruction. 620 105 - 30-second recovery rate (%) 91.2 50.0 - Recovery time is 60 seconds G'(Pa) after destruction. 665 130 - 60-second recovery rate (%) 97.8 61.9 - Can it complete 3 cycles? able Yes (but with a low recovery rate). -

[0068] As shown in Table 5, only the Schiff base system exhibits self-healing ability, but its initial modulus and recovery rate are significantly lower than those of Example 1. This indicates that calcium ion coordination bonds not only enhance initial mechanical strength but also facilitate faster recombination of the Schiff base network through physical cross-linking. There is a synergistic effect between the double bonds, rather than a simple additive effect.

[0069] (3) The liver puncture hemostasis test in mice was conducted under the same conditions as in Example 1. A total of 8 mice were tested, and the results are shown in Table 6:

[0070] Table 6 Results of hemostasis time by liver puncture in mice

[0071] Group Hemostasis time (seconds, mean ± SD) Hemostasis success rate (%) Gel adhesion Example 1 22.4±3.1 100 Fits snugly without falling off Comparison Group 1 45.2±5.6 87.5 (1 mouse experienced rebleeding) Partially cracked, soaked with blood Comparison Group 2 112±18 25.0 (6 cases failed to stop bleeding) The gel is soft and easily washed away by the blood.

[0072] Table 6 shows that Example 1 achieved the shortest hemostasis time and was successful in all cases. Only the Schiff base group had insufficient gel strength, resulting in local rupture under bleeding pressure and slow self-healing (recovery rate 50%), failing to close the wound in time. Only the Ca2+ coordination group was almost ineffective, indicating that simple ionic cross-linking cannot meet the requirements for rapid hemostasis.

[0073] (4) In this experiment, the gels of each group were mixed and prepared into circular gel sheets with a diameter of 10 mm and a thickness of 2 mm. The sheets were fixed on a pressure device and stained saline was injected at a constant flow rate. The pressure (mmHg) at the time of gel rupture was recorded (simulating the pressure of pulsating bleeding). Six samples were tested in each group. The results are shown in Table 7.

[0074] Table 7 Results of Blasting Strength Test

[0075] Group Average blasting strength (mmHg) Range (mmHg) Example 1 158±12 142-172 Comparison Group 1 62±8 52-74 Comparison Group 2 The gel could not form sheets; testing was not conducted. -

[0076] As shown in Table 7, the venous pressure in the human body is approximately 5-10 mmHg, and the arterial pressure is approximately 80-120 mmHg. The burst strength of Example 1 reached 158 mmHg, which can withstand arterial bleeding pressure, while the Schiff base group only reached 62 mmHg, making it extremely easy to rupture in pulsatile arterial bleeding.

[0077] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A self-healing, fast-acting, hemostatic bandage gel dressing, characterized in that: The gel dressing is a two-component spray gel, comprising an independently packaged first precursor solution and a second precursor solution, wherein the volume ratio of the first precursor solution to the second precursor solution is 1:

1. The first precursor solution comprises, by weight-volume percentage (w / v), 2-8% catechol-modified sodium alginate, 0.5-2% tranexamic acid, and the balance being phosphate buffer at pH 7.

4. The second precursor solution comprises, by weight-volume percentage (w / v), 1-5% sodium alginate, 0.1-0.5% calcium chloride, 0.01-0.1% recombinant human thrombin, and the balance being deionized water; The gel dressing is operated by one hand by pressing and spraying through a dual-chamber spray bottle. The two precursor solutions are mixed in equal volumes at the moment of spraying, forming a self-healing hydrogel on the wound surface within 10-60 seconds.

2. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 1, characterized in that, The degree of substitution of the catechol-modified sodium alginate is 15-35%.

3. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 2, characterized in that, The method for preparing the catechol-modified sodium alginate includes: dissolving sodium alginate in 0.1M MES buffer at pH 5.5, adding 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide to activate the carboxyl group, then adding dopamine hydrochloride, reacting at room temperature in the dark for 12-24 hours, and then lyophilizing by dialyzing to obtain the product.

4. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 1, characterized in that: The oxidation degree of the oxidized sodium alginate is 40-60%.

5. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 4, characterized in that, The method for preparing the oxidized sodium alginate includes: dissolving sodium alginate in deionized water, adding sodium periodate, reacting in the dark for 2-6 hours, adding ethylene glycol to terminate the reaction, and dialysis and freeze-drying to obtain the product.

6. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 1, characterized in that: The first precursor solution also contains 0.1-1% by weight / volume of an antimicrobial peptide.

7. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 6, characterized in that: The antimicrobial peptide is ε-polylysine or nisin.

8. The self-healing, rapid-acting hemostatic bandage gel dressing according to claim 1, characterized in that: The dual-chamber spray bottle includes a first liquid storage chamber, a second liquid storage chamber, a press pump head, and a mixing nozzle. The first liquid storage chamber is used to contain a first precursor solution, and the second liquid storage chamber is used to contain a second precursor solution. When the pump head is pressed, the solutions in the two chambers enter the mixing nozzle through independent channels in equal volume proportions. After converging at the nozzle, they are sprayed out in the form of mist or droplets.

9. A method for preparing a self-healing, rapid-closing, hemostatic bandage gel dressing, comprising the preparation of any one of claims 1-8, characterized in that, Includes the following steps: S1. Sodium alginate was dissolved in 0.1M MES buffer at pH 5.5 to prepare a 1-3% (w / v) solution. 1-Ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added at a molar ratio of 1:0.5-1 relative to the carboxyl groups of sodium alginate to activate the carboxyl groups. After activation for 30 minutes, dopamine hydrochloride was added at a molar ratio of 1:0.5-1.5 relative to the carboxyl groups of sodium alginate. The pH was adjusted to 5.5, and the reaction was carried out at room temperature in the dark for 24 hours. After the reaction was completed, the solution was dialyzed with deionized water for 3 days and then lyophilized to obtain catechol-modified sodium alginate. S2, dissolve sodium alginate in deionized water to prepare a 1-2% (w / v) solution, add sodium periodate, the molar ratio of sodium periodate to sodium alginate sugar units is 1:0.2-0.5, react in the dark for 4 hours, add ethylene glycol to terminate the reaction, dialyze with deionized water for 2 days, and freeze dry to obtain oxidized sodium alginate. S3, the obtained catechol-modified sodium alginate, tranexamic acid solution and antimicrobial peptide are placed in phosphate buffer at pH 7.4 to make the final concentration of catechol-modified sodium alginate 2-8% (w / v) and the final concentration of tranexamic acid 0.5-2% (w / v). The solution is then sterilely filtered through a filter membrane to obtain the first precursor solution. S4, the obtained sodium oxidized alginate, calcium chloride and recombinant human thrombin are dissolved in deionized water to make the final concentration of sodium oxidized alginate 1-5% (w / v) and the final concentration of calcium chloride 0.1-0.5% (w / v). The solution is then sterile filtered through a filter membrane to obtain the second precursor solution. S5, the first precursor solution and the second precursor solution are respectively filled into the first and second storage chambers of the dual-chamber spray bottle and sealed.

10. The method for preparing the self-healing, rapid-acting hemostatic bandage gel dressing according to claim 1, characterized in that: The filter membranes used in steps S3 and S4 are both 0.22 μm.

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