Adhesive liquid bandage hemostatic gel dressing and method of making same

Abstract

The application discloses a kind of liquid bandage hemostatic gel dressings with adhesion and preparation method thereof, the dressing is pH-responsive liquid precursor, comprising amino-oxy modified first polysaccharide, second polysaccharide containing aldehyde group and catechol, and iron ion, keep liquid flow at acidic pH, contact physiological pH environment after being applied to bleeding wound, form in situ within 10-30 seconds double-network hydrogel crosslinked with oxime bond, and catechol complexation crosslinking of iron ion, and realize wet state tissue adhesion through catechol group, hemostatic time is not more than 45 seconds;The application solves the problem of slow solidification and poor wet adhesion of existing liquid bandage through the double-network synergistic crosslinking mechanism triggered by pH response, realizes the effect of rapid hemostasis and firm plugging wound.

Description

Technical Field

[0001] This invention relates to the field of medical biomaterials technology, and in particular to an adhesive liquid bandage hemostatic gel dressing and its preparation method. Background Technology

[0002] Traditional hemostatic materials such as gauze, bandages, and tourniquets have limited effectiveness in stopping irregular wounds, deep wounds, or arterial bleeding, and often require significant pressure during application, which can easily cause secondary damage. Liquid bandages and injectable hemostatic gels have attracted widespread attention due to their ability to conform to wounds of any shape and their ease of application. For example, hemostatic gels based on chitosan and its derivatives can promote coagulation through the interaction of positive charges with the negative charges of erythrocyte membranes; hydrogel dressings based on natural polymers such as alginate and gelatin have also been reported for wound hemostasis.

[0003] First, most products struggle to achieve rapid and secure adhesion to moist, bleeding wounds. During hemostasis, the dressing is easily washed away by the blood flow, leading to hemostasis failure or the need for repeated application. Second, many hemostatic gels have a slow curing speed, typically requiring 1-3 minutes from application to the formation of an effective gel. This is insufficient to meet clinical needs in scenarios requiring near-instantaneous hemostasis, such as arterial bleeding or extensive oozing.

[0004] Therefore, in response to the problems mentioned above, this invention proposes an adhesive liquid bandage hemostatic gel dressing and its preparation method. Summary of the Invention

[0005] To overcome the insufficient adhesion of liquid bandages and hemostatic gel dressings on moist wound surfaces in existing technologies, this invention proposes an adhesive liquid bandage hemostatic gel dressing and its preparation method.

[0006] The technical solution of this invention is: an adhesive liquid bandage hemostatic gel dressing, wherein the dressing is a pH-responsive liquid precursor that maintains a liquid flow state under acidic pH conditions. When applied to a bleeding wound and exposed to a physiological pH environment, it forms an in-situ tissue-adhesive double-network hydrogel. The dressing comprises the following components:

[0007] A water-soluble first polysaccharide modified with an amino group, wherein the amino group is linked to the side chain of the first polysaccharide via an amide bond or an ester bond, wherein the first polysaccharide includes one or more of carboxymethyl chitosan, carboxymethyl dextran, and alginate derivatives, and the degree of substitution of the amino group is 10-40%;

[0008] A second polysaccharide containing aldehyde and catechol groups, comprising one or more of sodium alginate oxidized, dextran oxidized and hydroxyethyl starch oxidized, wherein the aldehyde content is 2-15 mmol / g and the grafting rate of catechol groups is 5-30%;

[0009] Ferric ions (Fe3+ or Fe2+) at a concentration of 0.5-5 mmol / L;

[0010] Pharmaceutical buffer solution, adjusting the pH of the entire system to 4.0-5.5, including 2-morpholine ethanesulfonic acid buffer, acetate-sodium acetate buffer or phosphate buffer solution, with a concentration of 10-100 mM;

[0011] A coagulation promoter comprising at least one of calcium ions, magnesium ions, thrombin, vitamin K, tranexamic acid and Bletilla striata polysaccharide, wherein the total concentration of the coagulation promoter in the dressing is 0.1-5% w / v;

[0012] An antibacterial component, selected from at least one of silver ions, nano-silver, chitosan quaternary ammonium salt, polyhexamethylene biguanide and chlorhexidine, wherein the concentration of the antibacterial component is 0.01-1% w / v;

[0013] The mass ratio of the first polysaccharide to the second polysaccharide is 1:0.5-3, and the molar ratio of ferric ions or ferrous ions to the catechol groups in the second polysaccharide is 0.1-0.5:1. At pH 4.0-5.5, the oxime bond formation reaction between the amino group of component one and the aldehyde group of component two is inhibited, and the coordination effect of the catechol groups with iron ions is weak. When the dressing is applied to the bleeding wound, the increase in pH promotes the rapid formation of oxime bonds as the first cross-linking network, while the deprotonation of catechol enhances the coordination effect with iron ions as the second cross-linking network, thereby forming a double-network hydrogel within 10-30 seconds. This hydrogel achieves wet adhesion through the covalent bonds and physical interactions between the catechol groups and the proteins on the tissue surface, and its hemostasis time does not exceed 45 seconds.

[0014] Preferably, the first polysaccharide is carboxymethyl chitosan with a molecular weight of 10-100 kDa, a degree of deacetylation of 80-95%, and a degree of carboxymethyl substitution of 0.6-1.2; the amino group is grafted onto the carboxyl or amino group of carboxymethyl chitosan by 3-aminooxypropionic acid, aminooxyacetic acid, or aminooxyethylamine via EDC / NHS coupling reaction.

[0015] Preferably, the second polysaccharide is sodium alginate oxidized with an oxidation degree of 20-50%, a molecular weight of 50-300 kDa, and a G / M ratio of 0.5-1.5; the catechol group is obtained by chemically grafting dopamine or 3,4-dihydroxyphenylpropionic acid onto the unoxidized carboxyl group of sodium alginate oxidized with EDC / NHS.

[0016] This invention proposes a method for preparing an adhesive liquid bandage hemostatic gel dressing, comprising the following steps:

[0017] S1, the first polysaccharide is dissolved in 2-morpholine ethanesulfonic acid buffer, EDC and NHS are added to activate the carboxyl group, then 3-aminooxypropionic acid or aminooxyacetic acid is added, the reaction is carried out at room temperature for 12-24 hours, dialyzed and lyophilized to obtain aminooxy modified first polysaccharide.

[0018] S2, firstly, sodium alginate or dextran is oxidized with sodium periodate to obtain oxidized polysaccharide, which is then dialyzed and lyophilized. Then, the oxidized polysaccharide is dissolved in phosphate buffer solution, and EDC, NHS and dopamine or 3,4-dihydroxyphenylpropionic acid are added. The reaction is carried out in the dark for 12-24 hours. After dialyzed and lyophilized, a second polysaccharide containing both aldehyde and catechol is obtained.

[0019] S3. Dissolve the obtained aminooxylated modified first and second polysaccharides in pharmaceutical buffer at a mass ratio of 1:0.5-3. Add iron salt solution (ferrous sulfate, ferrous chloride, ferric ammonium sulfate or ferric chloride) until the final iron ion concentration is 0.5-5 mmol / L. Adjust the pH to 4.0-5.5 with acid or alkali. Then add coagulation promoter and antibacterial components, mix well, and sterilize by sterile filtration or autoclaving. Dispense into sterile containers to obtain liquid bandage hemostatic gel dressing.

[0020] Preferably, the molar ratio of the first polysaccharide to 3-aminooxypropionic acid in step S1 is 1:2 to 1:10;

[0021] The conditions for oxidizing sodium alginate with sodium periodate in step S2 include a molar ratio of sodium alginate to sodium periodate of 1:0.2-1:1, and reaction at 4-25°C in the dark for 2-12 hours.

[0022] The beneficial effects of this invention are:

[0023] 1. This invention utilizes a pH-responsive dual-network cross-linking mechanism. Under acidic storage conditions (pH 4.0-5.5), it maintains the dressing in a liquid flow state by inhibiting the oxime bond reaction between amino groups and aldehyde groups and the coordination of catechol groups with iron ions. When it comes into contact with the physiological pH (7.2-7.6) of the wound, oxime bonds are rapidly formed as the first cross-linking network. At the same time, the deprotonation of catechol enhances the coordination with iron ions as the second cross-linking network. In-situ gelation is completed within 10-30 seconds, controlling the hemostasis time to within 45 seconds. This solves the problems of slow curing speed and easy washing away by blood flow on bleeding wounds of existing liquid bandages.

[0024] 2. This invention introduces aldehyde and catechol groups simultaneously onto the second polysaccharide, enabling the gel to achieve a tissue adhesion strength of 18-29 kPa even in a wet blood environment through physical interactions such as covalent bonds and multiple hydrogen bonds between the catechol groups and tissue surface proteins. This overcomes the problem of insufficient adhesion of traditional hemostatic materials in the presence of blood, ensuring that the dressing firmly seals active bleeding wounds. 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] The hemostatic gel dressing of the present invention is a pH-responsive liquid precursor that maintains a liquid flow state under acidic pH conditions. When applied to a bleeding wound and exposed to a physiological pH environment, it forms a double-network hydrogel with tissue adhesion in situ.

[0029] Specifically, the dressing of the present invention comprises the following components:

[0030] A water-soluble first polysaccharide modified with an amino group, wherein the amino group is linked to the side chain of the first polysaccharide via an amide bond or an ester bond, and the first polysaccharide is selected from one or more of carboxymethyl chitosan, carboxymethyl dextran and alginate derivatives, and the degree of substitution of the amino group is 10-40%;

[0031] A second polysaccharide containing aldehyde and catechol groups, wherein the second polysaccharide is selected from one or more of sodium alginate oxidized, dextran oxidized and hydroxyethyl starch oxidized, wherein the aldehyde content is 2-15 mmol / g and the grafting rate of catechol groups is 5-30%;

[0032] Ferric ions (Fe) 3+ ) or ferrous ions (Fe 2+ Its concentration is 0.5-5 mmol / L;

[0033] Use a pharmaceutical buffer solution to adjust the pH of the entire system to 4.0-5.5.

[0034] The mass ratio of the first polysaccharide to the second polysaccharide is 1:0.5-3, and the ferric ions (Fe) 3+ ) or ferrous ions (Fe 2+ The molar ratio of the catechol group in the first polysaccharide to the catechol group in the second polysaccharide is 0.1-0.5:1.

[0035] In this invention, the oxime bond formation reaction between the amino group of the first polysaccharide and the aldehyde group of the second polysaccharide is significantly inhibited at pH 4.0-5.5 (because the optimal pH for oxime bond formation is usually in the weakly acidic to slightly alkaline range, and the reaction rate is extremely slow below pH 5). Simultaneously, the coordination of the catechol group with iron ions is also weak under acidic conditions. Therefore, the dressing is a low-viscosity liquid in its storage state, exhibiting good injectability and sprayability. When the dressing is applied to a bleeding wound (normal physiological pH is 7.2-7.6), the alkaline buffering capacity provided by the blood and wound environment rapidly raises the local pH to near neutral or weakly alkaline, at which point the two cross-linking reactions are activated almost simultaneously.

[0036] Specifically, an efficient oxime bond formation reaction occurs between the amino group and the aldehyde group, serving as the first cross-linking network and rapidly constructing the hydrogel's framework structure. Simultaneously, the deprotonated catechol groups form highly stable coordination complexes with iron ions (mainly generating monocatechin-iron, dicatechin-iron, and tricatechin-iron complexes), serving as the second cross-linking network and significantly enhancing the gel's mechanical strength and stability. The formation of these two networks exhibits temporal overlap and synergistic effects; the oxime bond network provides rapid gelation (forming a non-flowing gel within 10-30 seconds), while the coordination network gradually strengthens as the pH further equalizes, ultimately forming a dual-network hydrogel. This dual-network structure not only endows the dressing with excellent mechanical strength (compressive modulus up to 10-50 kPa), but the catechol groups, after deprotonation, expose hydroxyl groups that can undergo Michael addition or Schiff base reactions with nucleophilic groups such as amino and thiol groups on the surface of wound tissue proteins. Simultaneously, catechol can also engage in multiple physical interactions with metal ions and hydrogen bond acceptors on the tissue surface, thus achieving strong adhesion even on moist, blood-containing wounds. Hemostasis time can be controlled within 45 seconds.

[0037] In this embodiment, the components of the present invention will be described in detail:

[0038] The first polysaccharide of this invention is an aminooxyl-modified polysaccharide. Water-soluble polysaccharides were chosen as the backbone material because they possess good biocompatibility, biodegradability, and hemostatic activity. Carboxymethyl chitosan retains the positively charged hemostatic function of chitosan while improving its water solubility. The aminooxyl group (-O-NH2) is a highly nucleophilic group that can form a stable oxime bond (C=NO-) with an aldehyde group under mild conditions. The stability of the oxime bond is significantly higher than that of ordinary Schiff bases (imine bonds), and it is not easily hydrolyzed in an aqueous environment, thus ensuring the durability of the gel during in vivo use. The degree of substitution of the aminooxyl group is controlled between 10-40%. Too low a substitution level will lead to insufficient cross-linking points, resulting in slow or incomplete gel formation; too high a substitution level may affect the biocompatibility and solubility of the polysaccharide. The carboxymethyl chitosan has a molecular weight of 10-100 kDa, a degree of deacetylation of 80-95%, and a degree of carboxymethyl substitution of 0.6-1.2. The amino group is grafted onto the carboxyl or amino group of the carboxymethyl chitosan by 3-aminooxypropionic acid, aminooxyacetic acid, or aminooxyethylamine via EDC / NHS coupling reaction.

[0039] The second polysaccharide is a polysaccharide containing aldehydes and catechol. The aldehydes originate from the dialdehyde group formed by the oxidation of the vicinal diol structure on the polysaccharide chain with sodium periodate. The two aldehyde groups can react with different amino groups to form cross-linking points. The aldehyde content is controlled at 2-15 mmol / g. The catechol group (catechol) is chemically grafted onto the unoxidized carboxyl groups on the polysaccharide via EDC / NHS. The grafting rate of the catechol group is 5-30%. This group has three functions: first, it efficiently coordinates with iron ions under neutral to weakly alkaline conditions to form a second network; second, it adheres to the tissue surface; and third, it possesses antioxidant and anti-inflammatory activities, which are beneficial for wound healing. The sodium alginate oxide has an oxidation degree of 20-50%, a molecular weight of 50-300 kDa, and a G / M ratio of 0.5-1.5. The catechol group is obtained by grafting dopamine or 3,4-dihydroxyphenylpropionic acid onto the unoxidized carboxyl group of the sodium alginate oxide.

[0040] The metal ion is an iron ion, and the iron ion (Fe) selected in this invention is... 3+ or Fe 2+ The concentration of iron ions is extremely low (0.5-5 mmol / L), far below the cytotoxic threshold of most cells (typically >10 mmol / L). The coordination constant between iron ions and catechol is very high, forming stable complexes even at very low iron concentrations. At pH 4-5.5, the phenolic hydroxyl groups of catechol exist primarily in a non-dissociated form, with weak coordination to iron ions; when the pH rises above 7, the phenolic hydroxyl groups dissociate to form negatively charged phenoxy anions, resulting in a sharp increase in coordination with iron ions. This pH-gated characteristic ensures that iron ions only exert their cross-linking effect in the wound environment, without affecting storage stability. The molar ratio of iron ions to catechol groups is controlled at 0.1-0.5:1.

[0041] A pharmaceutical buffer solution is used to maintain the pH of the system at 4.0-5.5. This buffer solution is 2-morpholine ethanesulfonic acid buffer, acetate-sodium acetate buffer, or phosphate buffer solution, with a concentration of 10-100 mM and a pH of 4.5-5.0. The choice of buffer solution needs to consider the pH kinetics after mixing with blood: the citrate-sodium citrate buffer system shows a faster pH recovery after dilution, which is beneficial for rapid gelation; at the same time, citrate ions can chelate calcium ions in the blood, exhibiting a certain anticoagulant effect. However, the hemostatic mechanism of this invention mainly relies on physical barriers and adhesion rather than simply on the coagulation cascade, therefore the impact is relatively small.

[0042] This invention also includes coagulation promoters and antibacterial components. Coagulation promoters such as calcium ions (Ca...) 2+ ), magnesium ions (Mg 2+These components can directly activate coagulation factors; thrombin can rapidly catalyze the conversion of fibrinogen into fibrin; vitamin K assists in the synthesis of coagulation factors; tranexamic acid inhibits fibrinolysis; and Bletilla striata polysaccharide possesses traditional hemostatic activity. The addition of these components can further enhance the hemostatic effect, especially in patients with coagulation disorders. Antibacterial components such as silver ions, nano-silver, and chitosan quaternary ammonium salts can prevent wound infection and are suitable for contaminated wounds or wounds with delayed treatment.

[0043] This invention provides Embodiment 1:

[0044] S1, 5.0 g of carboxymethyl chitosan (CMCS) was weighed and dissolved in 500 mL of MES buffer (0.1 M, pH 5.5), and stirred until completely dissolved. EDC (5.8 g, 30 mmol) and NHS (3.5 g, 30 mmol) were added separately, and the carboxyl groups were activated at room temperature for 30 minutes. Then, 3-aminooxypropionic acid (3.2 g, 30 mmol) was added to the reaction solution, and the reaction was stirred at room temperature for 24 hours. After the reaction was completed, the reaction solution was transferred to a dialysis bag (molecular weight cutoff 3500 Da) and dialyzed against deionized water for 3 days (changing the water 4 times a day). The dialysis solution was freeze-dried to obtain a white spongy product (aminooxy-modified first polysaccharide), with a yield of approximately 82%. The degree of substitution of the aminooxy group was determined to be 28.6% by the 2,4,6-trinitrobenzenesulfonic acid method.

[0045] S2: Dissolve 10.0 g of sodium alginate in 1 L of deionized water. Add sodium periodate (4.3 g, 20 mmol) under light-protected conditions. Stir at room temperature for 6 hours, then add 5 mL of ethylene glycol to terminate the reaction. Continue stirring for 30 minutes. Dialyze the reaction solution with deionized water for 3 days and freeze-dry to obtain oxidized sodium alginate (OSA). The oxidation degree was determined to be 38.7% by the hydroxylamine hydrochloride method. Dissolve 5.0 g of the above OSA in 500 mL of PBS buffer (0.1 M, pH 6.0), add EDC (5.8 g) and NHS (3.5 g), activate the carboxyl groups for 30 minutes, then add dopamine hydrochloride (7.6 g, 40 mmol). React at room temperature for 24 hours under light-protected and nitrogen-protected conditions. After the reaction, adjust the pH to 3.5 with hydrochloric acid to stop the reaction. Dialyze (molecular weight cutoff 8000-14000 Da) for 3 days and freeze-dry to obtain a light gray product (a second polysaccharide containing aldehydes and catechols). The dopamine grafting rate was determined to be 24.3% by UV-Vis spectrophotometry (characteristic absorption at 280 nm); the aldehyde content was re-determined to be 8.2 mmol / g by the hydroxylamine hydrochloride method.

[0046] S3. Weigh the above-mentioned aminooxylated modified first polysaccharide and the second polysaccharide containing aldehyde and catechol at a mass ratio of 1:1.5, and dissolve them separately in 20mM 2-morpholine ethanesulfonic acid (MES) buffer (pH 4.5) to prepare stock solutions each containing 2% w / v. Mix 10mL of the aminooxylated modified first polysaccharide stock solution and 15mL of the second polysaccharide stock solution containing aldehyde and catechol, add 0.5mL of FeCl3 solution (final concentration 2mmol / L), and finely adjust the pH to 4.5 with 0.1M hydrochloric acid or sodium hydroxide. After the mixture is homogenized by stirring, filter it through a 0.22μm filter membrane for sterilization, dispense 10mL into sterile vials, seal and store at 4℃ to obtain a single-package liquid dressing.

[0047] This invention provides Embodiment 2:

[0048] The synthesis method described in Example 1 differs from the following:

[0049] The first polysaccharide was replaced with carboxymethyl dextran (molecular weight 50 kDa, degree of carboxymethyl substitution 0.8), and the degree of amino group substitution was designed to be 15.2%; the second polysaccharide was replaced with oxidized dextran (degree of oxidation 28%, molecular weight 70 kDa), with a dopamine grafting rate of 12.6% and an aldehyde content of 5.4 mmol / g; ferrous sulfate (Fe) was selected as the iron ion. 2+ The final concentration was 1 mmol / L; coagulation promoters (calcium chloride (final concentration 0.5% w / v) and Bletilla striata polysaccharide (final concentration 0.1% w / v)) were added; antibacterial components (chitosan quaternary ammonium salt (final concentration 0.05% w / v)) were added; the pharmaceutical buffer was acetate-sodium acetate buffer (50 mM, pH 5.0).

[0050] The mass ratio of the aminooxyl-modified first polysaccharide to the second polysaccharide containing aldehydes and catechol is 1:1.

[0051] This invention provides embodiment 3:

[0052] The synthesis method described in Example 1 differs from the following:

[0053] The first polysaccharide is an alginate derivative (sodium alginate modified with ethylenediamine to introduce amino groups, then grafted with amino groups), with an amino group substitution degree of 35.8%; the second polysaccharide is oxidized hydroxyethyl starch (oxidation degree 45%, molecular weight 200 kDa), with a dopamine grafting rate of 28% and an aldehyde content of 14.2 mmol / g; the iron ion is selected from ferric ammonium sulfate (Fe... 3+ The final concentration was 4.5 mmol / L; the pharmaceutical buffer was PBS buffer (10 mM, pH 4.0).

[0054] The mass ratio of the aminooxyl-modified first polysaccharide to the second polysaccharide containing aldehydes and catechol is 1:2.5.

[0055] This invention provides four sets of comparative examples, specifically:

[0056] Comparative Example 1 is essentially the same as Example 1, except that FeCl3 solution (containing no iron ions) is not added during preparation. This comparative example can only form a single oxime cross-linked network.

[0057] The second polysaccharide in Comparative Example 2 contained only oxidized sodium alginate (OSA) and was not grafted with dopamine (it only had aldehyde groups and no catechol groups). Everything else was the same as in Example 1.

[0058] Comparative Example 3 was essentially the same as Example 1, except that the pH was adjusted to 7.2 (physiological pH) during preparation. This sample had already undergone cross-linking during storage, resulting in a semi-solid gel state, and could not be used as a liquid precursor.

[0059] Comparative Example 4 used a commercially available brand of liquid bandage (the main ingredient of which is cyanoacrylate) as a control.

[0060] This example demonstrates the performance of the invention through experiments conducted on the above examples. Specifically:

[0061] (1) In this example, the gel time was determined by the inverted test tube method. The liquid dressing was placed in a 2 mL centrifuge tube, and an equal volume of PBS buffer (pH 7.4, simulating the physiological environment) was added and mixed quickly. Timing was started. The centrifuge tube was inverted every 5 seconds, and the time when the liquid stopped flowing was observed. This time was the gel time. Each sample was measured 5 times and the average value was taken.

[0062] (2) Adult SD rats (weighing 200-250g, half male and half female) were used in this experiment. After anesthesia with sodium pentobarbital injected intraperitoneally, the liver was exposed by opening the abdomen. A 1cm long and 0.5cm deep incision was made in the left lobe of the liver. After free bleeding for 5 seconds, 0.2mL of the test dressing (or control) was immediately applied. At the same time, the outflowing blood was collected by weighing. The time from the application of the dressing to the complete cessation of bleeding observed by the naked eye was recorded (hemostasis time). The mass of blood absorbed by the filter paper (blood loss) was also weighed. There were 6 rats in each group.

[0063] (3) The adhesion strength of wet tissue was tested using the overlap shear mode. Fresh pigskin was taken, subcutaneous fat was removed, and it was cut into rectangular strips of 2cm × 5cm. 0.1mL of the test dressing was evenly applied to the center of one strip of pigskin, and another strip of pigskin was immediately placed over it, with an overlap area of ​​1cm × 1cm. A pressure of 0.5N was applied for 30 seconds, and then the strip was quickly immersed in PBS (pH 7.4, 37℃) for 5 minutes. After that, a tensile shear test was performed on a universal testing machine at a speed of 10mm / min. The maximum breaking load was recorded, and the adhesion strength (kPa) was obtained by dividing the load by the overlap area. Each sample was tested 5 times.

[0064] (4) In this experiment, the compressive modulus and elongation at break of the gel were determined. First, each dressing was gelled at pH 7.4 and then prepared into a cylindrical gel with a diameter of 10 mm and a height of 10 mm. The gel was then compressed at a speed of 2 mm / min on a universal testing machine, and the stress-strain curve was recorded. The slope of the linear region was taken as the compressive modulus. The elongation at break was determined by tensile testing.

[0065] Table 1 Comparison of physicochemical properties and hemostatic properties of each embodiment and comparative example

[0066]

[0067] As shown in Table 1, the gelation time of the embodiments of the present invention is within the range of 10-30 seconds, the hemostasis time is no more than 45 seconds, and the wet adhesion strength is as high as 18-29 kPa, which is significantly better than Comparative Examples 1 and 2, which lack iron ions or catechol (adhesion strength is only 5-9 kPa). Although Comparative Example 1 still has an oxime bond network, it lacks coordination enhancement and catechol adhesion groups, resulting in a significant increase in hemostasis time and blood loss. Comparative Example 2 completely lacks catechol, which not only significantly reduces adhesion but also significantly reduces mechanical properties due to the absence of the double network. The commercially available liquid bandage Comparative Example 4 is made of cyanoacrylate, which has a slow curing speed and poor wet adhesion, a long hemostasis time, and is brittle and hard, making it unsuitable for dynamic wounds.

[0068] This example continues with tests on biocompatibility, degradability, and antibacterial properties, specifically:

[0069] (5) Take fresh anticoagulated rabbit blood (sodium citrate anticoagulation), add the test dressing (0.1 mL after gelation) to a centrifuge tube, add 0.2 mL of rabbit blood and 0.02 mL of CaCl2 solution (0.2 M) to initiate coagulation. After incubation at 37℃ for 5 minutes, add 10 mL of distilled water, gently mix to rupture uncoagulated red blood cells, then centrifuge at 3000 rpm for 5 minutes, and measure the absorbance of the supernatant at 540 nm. Use the distilled water + blood group as a blank control. BCI = (sample absorbance / blank absorbance) × 100%, the lower the BCI value, the better the coagulation performance.

[0070] (6) Weigh the gel precisely (W0) and immerse it in PBS (pH 7.4) containing lysozyme (1 mg / mL). Shake at 37°C (50 rpm). Remove the gel on days 7, 14, 21, and 28, freeze-dry and weigh (Wt). Degradation rate = (W0 - Wt) / W0 × 100%.

[0071] (7) Co-culture L929 mouse fibroblasts with gel extract for 24 hours, then add CCK-8 reagent, measure absorbance at 450 nm, and calculate cell viability. Cell viability ≥75% is considered acceptable (refer to ISO 10993-5 standard).

[0072] (8) Spread Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) bacterial suspensions on LB plates, place the gels (5 mm in diameter and 2 mm in thickness) from Examples 1 and 2 on the plates, incubate at 37°C for 24 hours, and measure the diameter of the inhibition zone.

[0073] Table 2 Biocompatibility, Degradability and Antibacterial Properties

[0074]

[0075] As shown in Table 2, the coagulation index of the dressing of this invention is significantly lower than that of the comparative example and commercially available products, indicating its strong procoagulant activity. The degradation performance is controllable, with 88-92% degradation within 28 days, meeting the requirements for absorbable hemostatic materials. Cell viability exceeds 85% in all cases, with no significant cytotoxicity. Example 2, with the addition of antibacterial components, showed good antibacterial activity against two common pathogenic bacteria. Example 1, without antibacterial components, showed no inhibition zone, as expected.

[0076] In this example, Example 1 was stored at 4°C and 25°C (protected from light) for 6 months, with samples taken monthly to test its appearance, pH, gelation time, and hemostasis time (in a rat liver model). The results are shown in Table 3.

[0077] Table 3. Stability test results (Example 1)

[0078]

[0079] As shown in Table 3, the dressing performance remained almost unchanged after 6 months of storage at 4℃; after 6 months of storage at 25℃, the gel time was slightly prolonged but still within 30 seconds, and the hemostasis time was still less than 45 seconds, which indicates that the product has good room temperature stability.

[0080] 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. An adhesive liquid bandage hemostatic gel dressing, characterized in that, The dressing is a pH-responsive liquid precursor that remains fluid under acidic pH conditions. When applied to a bleeding wound and exposed to a physiological pH environment, it forms an in-situ, tissue-adhesive, dual-network hydrogel. The dressing contains the following components: A water-soluble first polysaccharide modified with an amino group, wherein the amino group is linked to the side chain of the first polysaccharide via an amide bond or an ester bond, wherein the first polysaccharide includes one or more of carboxymethyl chitosan, carboxymethyl dextran, and alginate derivatives, and the degree of substitution of the amino group is 10-40%; A second polysaccharide containing aldehyde and catechol groups, comprising one or more of sodium alginate oxidized, dextran oxidized and hydroxyethyl starch oxidized, wherein the aldehyde content is 2-15 mmol / g and the grafting rate of catechol groups is 5-30%; Ferric ions (Fe3+ or Fe2+) at a concentration of 0.5-5 mmol / L; Use pharmaceutical buffer solution to adjust the pH of the entire system to 4.0-5.5; A coagulation promoter comprising at least one of calcium ions, magnesium ions, thrombin, vitamin K, tranexamic acid and Bletilla striata polysaccharide, wherein the total concentration of the coagulation promoter in the dressing is 0.1-5% w / v; An antibacterial component, selected from at least one of silver ions, nano-silver, chitosan quaternary ammonium salt, polyhexamethylene biguanide and chlorhexidine, wherein the concentration of the antibacterial component is 0.01-1% w / v.

2. The adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: The mass ratio of the first polysaccharide to the second polysaccharide is 1:0.5-3, and the molar ratio of ferric ions or ferrous ions to catechol groups in the second polysaccharide is 0.1-0.5:

1.

3. The adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: At pH 4.0-5.5, the oxime bond formation reaction between the amino group of component one and the aldehyde group of component two is inhibited, while the coordination effect of the catechol group with iron ions is weak. When the dressing is applied to the bleeding wound, the increase in pH promotes the rapid formation of oxime bonds as the first cross-linking network. At the same time, the deprotonation of catechol enhances the coordination effect with iron ions as the second cross-linking network, thereby forming a double-network hydrogel within 10-30 seconds. This hydrogel achieves wet adhesion through the covalent bonds and physical interactions between the catechol group and the proteins on the tissue surface, and the hemostasis time does not exceed 45 seconds.

4. The adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: The first polysaccharide is carboxymethyl chitosan, with a molecular weight of 10-100 kDa, a degree of deacetylation of 80-95%, and a degree of carboxymethyl substitution of 0.6-1.2; the amino group is grafted onto the carboxyl or amino group of carboxymethyl chitosan by 3-aminooxypropionic acid, aminooxyacetic acid, or aminooxyethylamine via EDC / NHS coupling reaction.

5. The adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: The second polysaccharide is sodium oxidized alginate with an oxidation degree of 20-50%, a molecular weight of 50-300 kDa, and a G / M ratio of 0.5-1.

5. The catechol group is obtained by chemically grafting dopamine or 3,4-dihydroxyphenylpropionic acid onto the unoxidized carboxyl group of sodium oxidized alginate using EDC / NHS.

6. The adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: The pharmaceutical buffer solution is 2-morpholine ethanesulfonic acid buffer, acetic acid-sodium acetate buffer, or phosphate buffer solution with a concentration of 10-100 mM.

7. The adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: The dressing is in single-package liquid form and can be used by squeezing it out with one hand.

8. A method for preparing an adhesive liquid bandage hemostatic gel dressing, comprising preparing the adhesive liquid bandage hemostatic gel dressing according to any one of claims 1-7, characterized in that, Includes the following steps: S1, the first polysaccharide is dissolved in 2-morpholine ethanesulfonic acid buffer, EDC and NHS are added to activate the carboxyl group, then 3-aminooxypropionic acid or aminooxyacetic acid is added, the reaction is carried out at room temperature for 12-24 hours, dialyzed and lyophilized to obtain aminooxy modified first polysaccharide. S2, firstly, sodium alginate or dextran is oxidized with sodium periodate to obtain oxidized polysaccharide, which is then dialyzed and lyophilized. Then, the oxidized polysaccharide is dissolved in phosphate buffer solution, and EDC, NHS and dopamine or 3,4-dihydroxyphenylpropionic acid are added. The reaction is carried out in the dark for 12-24 hours. After dialyzed and lyophilized, a second polysaccharide containing both aldehyde and catechol is obtained. S3. The obtained aminooxyl-modified first and second polysaccharides are dissolved in pharmaceutical buffer at a mass ratio of 1:0.5-3. Iron salt solution is added until the final iron ion concentration is 0.5-5 mmol / L. The pH is adjusted to 4.0-5.5 with acid or alkali. Then, coagulation promoter and antibacterial components are added, mixed evenly, and sterilized by sterile filtration or autoclaving. The mixture is then dispensed into sterile containers to obtain liquid bandage hemostatic gel dressing.

9. The method for preparing the adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: In step S1, the molar ratio of the first polysaccharide to 3-aminooxypropionic acid is 1:2 to 1:

10. The conditions for oxidizing sodium alginate with sodium periodate in step S2 include a molar ratio of sodium alginate to sodium periodate of 1:0.2-1:1, and reaction at 4-25°C in the dark for 2-12 hours.

10. The method for preparing the adhesive liquid bandage hemostatic gel dressing according to claim 1, characterized in that: In step S3, the ferric salt is ferrous sulfate, ferrous chloride, ferric ammonium sulfate, or ferric chloride. The dressing liquid precursor is sprayed or dripped directly onto the bleeding wound during use.

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