Composite hemostatic material and preparation method thereof

Abstract

The present invention belongs to the field of hemostatic materials and provides a composite hemostatic material and a preparation method thereof. The composite hemostatic material comprises a biomimetic adhesive and kaolin. The biomimetic adhesive is a composite of a catechol polymer, TA, and Gel; the kaolin accounts for 1% to 15% by weight. The preparation method comprises: adding DA and PEGDA to dimethyl sulfoxide and dissolving them; adding TEA to adjust the solution to alkalinity; heating the mixture for 2 hours, adding an excess of DA, continuing the reaction for 1 hour, filtering, and washing the filtrate to obtain the catechol polymer; preparing a Gel solution and a TA solution by taking Gel and TA; mixing the catechol polymer, Gel solution, and TA solution to obtain a biomimetic adhesive; freeze-drying the biomimetic adhesive, pulverizing it, mixing it with kaolin powder, adding water and stirring to form a gel, freeze-drying, and pulverizing it to obtain the composite hemostatic material. The composite hemostatic material has strong adhesion, can effectively physically seal wounds, and can quickly and effectively stop bleeding.

Description

Technical Field

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

[0002] Different types of hemostatic materials are used to address different bleeding situations. For arterial hemostasis, the main types include tourniquets, hemostatic gauze, hemostatic sponges, and hemostatic powders. Tourniquets are applied proximally to the injured limb by physically tightening it to block blood flow and prevent exsanguination. However, tourniquets generally only address bleeding in the extremities and lack wound protection or coagulation. Hemostatic gauze and sponges can apply pressure or packing to the bleeding site. However, for arterial or large wound bleeding, larger amounts or larger areas of gauze and sponges require continuous pressure, which can cause secondary damage to delicate tissues or organs at the wound site. Hemostatic powders can achieve hemostasis by covering the wound and promoting coagulation, but most hemostatic powders are easily washed away by the blood and are therefore only suitable for smaller wounds. Therefore, developing a hemostatic material that can rapidly stop bleeding, coagulate blood, and form strong tissue adhesion, suitable for arterial and large wound bleeding, is of great practical and economic value. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention aims to provide a composite hemostatic material which has strong adhesion, can form a physical blockage on the wound, and has fast hemostasis and good hemostatic effect.

[0004] The technical solution adopted in the present invention is as follows:

[0005] A composite hemostatic material, comprising a biomimetic adhesive and kaolin, wherein the biomimetic adhesive is a composite of catechol polymer, tannic acid and gelatin;

[0006] The mass proportion of the kaolin is 1% to 15%.

[0007] Furthermore, the catechol polymer is prepared by Michael addition reaction of polyethylene glycol diacrylate and dopamine hydrochloride.

[0008] Furthermore, the dopamine hydrochloride is grafted to the carbon-carbon double bond at the end of the polyethylene glycol diacrylate via an amino group.

[0009] Furthermore, the catechol polymer does not contain a vinyl group.

[0010] Furthermore, the biomimetic adhesive is prepared by mixing catechol polymer, 10 w / v% gelatin solution and 20 w / v% tannic acid solution in a volume ratio of 3:2:8.

[0011] Furthermore, the composite hemostatic material is prepared by mixing the powder of the biomimetic adhesive with the kaolin powder, adding water and stirring to form a gel, freeze-drying, and pulverizing;

[0012] Alternatively, the composite hemostatic material is prepared by mixing the powder of the biomimetic adhesive with the kaolin powder, adding water and stirring to form a gel, freeze-drying, and crushing the mixture. The crushed mixture is then loaded into a polyvinyl alcohol water-soluble film bag.

[0013] Furthermore, the mass proportion of the kaolin in the composite hemostatic material is 10% to 15%.

[0014] Furthermore, the biomimetic adhesive and kaolin in the composite hemostatic material are cross-linked through hydrogen bonds.

[0015] A method for preparing the composite hemostatic material as described in any one of the above items comprises the following steps:

[0016] S1, weigh dopamine hydrochloride and polyethylene glycol diacrylate, add dimethyl sulfoxide, and stir until dissolved into a transparent clear solution;

[0017] S2, adding triethylamine to adjust the pH to alkaline;

[0018] S3, after heating and reacting for 2 hours, dopamine hydrochloride was added until it was excessive, and the reaction was continued for 1 hour. The filtrate was filtered and collected, and the filtrate was washed with methyl tert-butyl ether. After standing and stratification, the upper liquid was removed, and the methyl tert-butyl ether was removed in a vacuum drying oven to obtain a catechol polymer;

[0019] S4, respectively weighing gelatin and tannic acid to prepare gelatin solution and tannic acid solution;

[0020] S5, stirring and mixing the catechol polymer, gelatin solution and tannic acid solution to prepare a biomimetic adhesive;

[0021] S6, freeze-drying and crushing the biomimetic adhesive;

[0022] S7, mixing the crushed biomimetic adhesive powder with kaolin powder to prepare a composite hemostatic material precursor;

[0023] S8, taking the composite hemostatic material precursor, adding water, stirring to form a gel, freeze-drying, and crushing to obtain a composite hemostatic material.

[0024] Furthermore, one or more of the following conditions are included:

[0025] Steps S1, S2 and S3 are all carried out in the absence of light and under nitrogen protection;

[0026] In step S5, the catechol polymer and tannic acid solution are first mixed evenly, and then the gelatin solution is added and stirred to prepare a biomimetic adhesive;

[0027] In step S8, the mass ratio of the composite hemostatic material precursor to water is 1:5;

[0028] In step S8, the obtained composite hemostatic material is sealed in a polyvinyl alcohol water-soluble film bag to obtain a composite hemostatic material product.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention combines a biomimetic adhesive with kaolin to obtain a new composite hemostatic material. The composite hemostatic material has excellent anti-swelling properties and stronger adhesion than the biomimetic adhesive, and can be used for hemostasis of arteries / large wounds, as well as hemostasis in humid / underwater environments. After absorbing water to form a gel, it becomes a liquid-like material with good stability and certain fluidity, can spread well on the tissue surface and fully and closely contact the tissue, thereby enhancing the hemostatic ability. When used for hemostasis, the composite hemostatic material can quickly absorb water in the blood to form a gel and adhere to the wound. It can not only achieve physical sealing of the wound through strong adhesion to the vascular wound, but also can simultaneously initiate a coagulation cascade reaction through kaolin to exert a coagulation effect, thereby achieving rapid hemostasis.

[0031] Kaolin, as a hemostatic material, possesses excellent water absorption, can concentrate platelets and thrombin in the blood, activate coagulation factors, and promote coagulation and hemostasis. However, kaolin itself has low adhesion (significantly less than that of biomimetic adhesives), making it unsuitable for use alone as a hemostatic agent for arterial bleeding. Adding kaolin to a hemostatic material can lead to a certain degree of loss of adhesion. However, the composite kaolin used in this application yields a hemostatic material with improved adhesion and superior hemostatic properties. In particular, composite hemostatic materials containing 10% to 15% kaolin by mass exhibit superior adhesion and hemostatic properties.

[0032] When preparing the composite hemostatic material, the obtained paste-like biomimetic adhesive glue contains excess water. If it is directly mixed with kaolin, it is difficult to accurately quantify the mass proportion of kaolin. The biomimetic adhesive is first freeze-dried into a powder and then compounded with kaolin, where the kaolin content is more accurately controlled. After the biomimetic adhesive powder is mixed with the kaolin powder, water is added to form a gel, which ensures that the biomimetic adhesive and kaolin fully react chemically. After the product is obtained by freeze-drying, it can obtain stable hemostatic performance when used for hemostasis and is easy to store and transport. The composite hemostatic material can be used in different ways according to needs and has good adaptability. For example, after adding deionized water to mix into a gel and applying it to the wound, it is particularly suitable for the treatment of internal wounds, such as abdominal and thoracic wounds. Or the powder can be directly applied to the wound, which is suitable for the treatment of surface wounds. The powder can also be loaded into a polyvinyl alcohol water-soluble film bag for hemostasis, which can adapt to different parts, especially those with large blood flow and internal wounds, and can prevent the composite hemostatic material from being washed away or adhering to other parts. The composite hemostatic material is packed in a polyvinyl alcohol water-soluble film bag, which is convenient for sterile storage and accurate use. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 This is a flow chart for preparing the composite hemostatic material of the present invention.

[0035] Figure 2 The reaction formula for preparing catechol polymer (DP) is shown in FIG.

[0036] Figure 3 This is a photo of the DP prepared in the present invention.

[0037] Figure 4 This is a photo of the biomimetic adhesive (DP@TA / Gel) paste prepared in the present invention.

[0038] Figure 5 This is a photo of the composite hemostatic material (DP@TA / Gel-kao) prepared in the present invention.

[0039] Figure 6 FT-IR spectra of dopamine hydrochloride (DA), polyethylene glycol diacrylate (PEGDA) and catechol polymer (DP).

[0040] Figure 71H NMR spectra of DA, PEGDA and DP.

[0041] Figure 8 FT-IR spectra of tannic acid (TA), gelatin (Gel), catechol polymer (DP) and biomimetic adhesive (DP@TA / Gel).

[0042] Figure 9 FT-IR spectra of kaolinite, biomimetic adhesive (DP@TA / Gel), DP@TA / Gel-kao5, DP@TA / Gel-kao10 and DP@TA / Gel-kao15.

[0043] Figure 10 These are the XRD patterns of DP@TA / Gel, DP@TA / Gel-kao1, DP@TA / Gel-kao2, DP@TA / Gel-kao5, DP@TA / Gel-kao10 and DP@TA / Gel-kao15.

[0044] Figure 11 The swelling rates of composite hemostatic materials with different kaolin contents after being immersed in PBS for different times.

[0045] Figure 12 Adhesion curves showing the adhesion strength of composite hemostatic materials with different kaolin contents on fresh pig skin as a function of tensile displacement.

[0046] Figure 13 are the storage modulus (G') and loss modulus (G") values ​​of the composite hemostatic material under different strains after absorbing water and forming gel; where: A is DP@TA / Gel; B is DP@TA / Gel-kao1; C is DP@TA / Gel-kao2; D is DP@TA / Gel-kao5; E is DP@TA / Gel-kao10; and F is DP@TA / Gel-kao15.

[0047] Figure 14 These are photos of the surgical operation process of Experimental Test Example 9; among them, a is the operation of stripping muscle tissue through incision, b is the operation of stripping and picking out the artery, and c is the operation of clamping the blood vessel with hemostatic forceps and then cutting open the blood vessel.

[0048] Figure 15 These are photos of the experimental groups (Groups A, B, C, and D) in Experimental Test Example 9 after hemostasis operation.

[0049] Figure 16 This is a photo of the gauze used after the hemostatic operation in the control group (Groups E and F) of Experimental Test Example 9. DETAILED DESCRIPTION

[0050] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0051] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0052] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a composite hemostatic material, comprising the following steps:

[0053] S1. Add dimethyl sulfoxide (DMSO) as the reaction solvent to a three-necked flask. After checking the apparatus for airtightness, pre-bubble nitrogen for 10 minutes to remove the solvent and oxygen from the flask. Then, weigh dopamine hydrochloride (DA) and polyethylene glycol diacrylate (PEGDA) and add them to the three-necked flask. Stir to dissolve DA and PEGDA until a clear solution is formed. The molar ratio of DA to PEGDA is preferably 1:1.

[0054] S2, adding triethylamine (TEA) to the transparent clear solution to adjust the pH of the solution to alkaline, preferably to about 8.0.

[0055] S3, placing the three-necked flask in an oil bath, heating at 80°C for 2 h, then adding excess DA and continuing the reaction for 1 h. After the reaction is completed, filtering the product with a disposable filter to remove possible ammonium salts, and collecting the filtrate;

[0056] Add methyl tert-butyl ether to the filtrate for washing, stir thoroughly until turbid, let it stand and separate, remove the upper liquid, preferably repeat the washing 5 times, put it in a vacuum drying oven and let it stand at room temperature to remove the residual methyl tert-butyl ether, and obtain a yellow transparent liquid catechol polymer (DP). Figure 2 and 3 Analysis showed that the catechol polymer (DP) was generated from PEGDA and DA via Michael addition reaction.

[0057] The molar mass ratio of the amount of DA added in step S3 to the amount of DA added for the first time is preferably controlled to be 0.5: 1. Step S1, step S2 and step S3 are all carried out in the dark and under nitrogen protection.

[0058] S4. Weigh a certain amount of gelatin (Gel), add a certain amount of deionized water, heat and stir in a container until it reaches about 45°C to completely dissolve the Gel, and prepare a Gel solution. Weigh a certain amount of tannic acid (TA), add a certain amount of deionized water, and stir and dissolve at room temperature to obtain a TA solution.

[0059] Preferably, the Gel solution is prepared with a concentration of 10 w / v% and the TA solution is prepared with a concentration of 20 w / v%.

[0060] S5, the DP, Gel solution and TA solution prepared above are mixed in a certain proportion and stirred evenly to prepare a biomimetic adhesive (DP@TA / Gel), such as Figure 4 As shown, the paste was washed with deionized water and collected after standing at room temperature to obtain the desired biomimetic adhesive (DP@TA / Gel).

[0061] Preferably, when mixing the DP, Gel solution, and TA solution in step S5, the DP and TA solutions are first stirred and mixed evenly, and then the Gel solution is added and stirred and mixed to prepare the biomimetic adhesive (DP@TA / Gel). Mixing in this order effectively ensures gelation.

[0062] Furthermore, the TA solution is added to the DP solution and stirred rapidly immediately upon addition. After thorough mixing, the Gel solution is added and stirred rapidly and thoroughly. This allows the polymers to interact with each other and form a regular arrangement, allowing them to quickly precipitate into a gel from the aqueous solution. However, it should be noted that changing the order of addition or failing to stir promptly can result in incomplete or poor gelation.

[0063] Preferably, DP, 10 w / v% Gel solution, and 20 w / v% TA solution are mixed in a volume ratio of 3:2:8 to prepare DP@TA / Gel.

[0064] S6, freeze-drying the prepared paste-like biomimetic adhesive (DP@TA / Gel), and grinding it into powder after drying to obtain biomimetic adhesive (DP@TA / Gel) powder.

[0065] S7, the biomimetic adhesive (DP@TA / Gel) powder and kaolin (Kao) powder are mixed in a certain proportion to prepare a composite hemostatic material precursor.

[0066] The mass proportion of kaolin is preferably controlled to be 1% to 15%.

[0067] More preferably, the mass proportion of kaolin in the composite hemostatic material is controlled to 10% to 15%, thereby obtaining a composite hemostatic material with better adhesion and better hemostatic effect.

[0068] S8, taking the above composite hemostatic material precursor, adding water and stirring to form gel, freeze-drying and crushing after the formation, to obtain composite hemostatic material (DP@TA / Gel-kao) powder.

[0069] Preferably, the mass ratio of the composite hemostatic material precursor to water is controlled at approximately 1:5, and approximately 5 times the weight of water is added to the mixture before stirring to form a gel. The composite hemostatic material can be stirred and mixed evenly, absorbs water to form a gel, and does not retain excess water. Excessive water content can lead to problems such as kaolin powder floating, prolonged freeze-drying time, and high energy consumption. Too little water content can easily lead to uneven stirring and insufficient water absorption, affecting the uniformity of product quality.

[0070] Example 1

[0071] Take 60mL of dimethyl sulfoxide and add it to a three-necked flask. After checking the airtightness, introduce nitrogen for 10 minutes to remove the solvent and oxygen in the three-necked flask. Then, weigh 7.6g (40mmol) of DA and 24g (40mmol) of PEGDA and add them to the three-necked flask. Stir to dissolve DA and PEGDA until a transparent clear solution is formed.

[0072] An appropriate amount of TEA was added to the transparent clear solution to adjust the pH of the solution to about 8.0.

[0073] Place the three-necked flask in an oil bath and heat at 80°C for 2 h. Then add excess DA (3.8 g, 20 mmol) and continue the reaction for 1 h. After the reaction is completed, filter the product with a disposable filter to remove possible ammonium salts, and collect the filtrate.

[0074] Methyl tert-butyl ether was added to the filtrate for washing, and the filtrate was stirred thoroughly until turbid and then allowed to stand for stratification. The upper liquid was removed and the washing was repeated 5 times. After washing, the filtrate was placed in a vacuum drying oven and allowed to stand to remove the residual methyl tert-butyl ether at room temperature to obtain a yellow transparent liquid DP.

[0075] The above reactions were all carried out in the dark and under nitrogen protection.

[0076] Weigh Gel and add deionized water to prepare a Gel solution with a concentration of 10 w / v%. Weigh TA and add deionized water to prepare a TA solution with a concentration of 20 w / v%.

[0077] DP, Gel solution and TA solution were mixed in a volume ratio of 3:2:8 to prepare DP@TA / Gel paste.

[0078] The paste DP@TA / Gel was freeze-dried and then ground into powder to obtain DP@TA / Gel dry powder.

[0079] DP@TA / Gel powder and kaolin powder were mixed at a mass ratio of 99:1 (i.e., the kaolin content was 1%) to prepare a composite hemostatic material precursor.

[0080] The composite hemostatic material precursor was taken, 5 times its weight of deionized water was added, and the mixture was stirred and mixed evenly until it became a gel, and then freeze-dried. After drying, the mixture was ground and pulverized to obtain the composite hemostatic material DP@TA / Gel-kao1.

[0081] Example 2

[0082] The method is basically the same as Example 1, except that DP@TA / Gel powder and kaolin powder are mixed at a mass ratio of 49:1 (ie, the kaolin content is 2%) to obtain DP@TA / Gel-kao2.

[0083] Example 3

[0084] The method is basically the same as Example 1, except that DP@TA / Gel powder and kaolin powder are mixed at a mass ratio of 19:1 (ie, the kaolin content is 5%) to obtain DP@TA / Gel-kao5.

[0085] Example 4

[0086] The method is basically the same as Example 1, except that DP@TA / Gel powder and kaolin powder are mixed in a mass ratio of 9:1 (ie, the kaolin content is 10%) to obtain DP@TA / Gel-kao10.

[0087] Example 5

[0088] The method is basically the same as Example 1, except that DP@TA / Gel powder and kaolin powder are mixed in a mass ratio of 17:3 (ie, the kaolin content is 15%) to obtain DP@TA / Gel-kao15.

[0089] In summary, the specific compositions of the composite hemostatic materials (DP@TA / Gel-kao) prepared in Examples 1-5 are shown in Table 1 below.

[0090] Table 1 Ratios of sample components in Examples 1-5

[0091]

[0092] Experimental test example 1

[0093] The raw materials DA, PEGDA and the intermediate product DP were tested by Fourier-transform infrared spectrometer (FT-IR) in the wave number range of 4000-400 cm -1 .

[0094] like Figure 6 Shown are the FT-IR spectra of DA, PEGDA and DP.

[0095] For DA, the analysis results show that 3336.4cm -1 The N—H stretching vibration absorption peak on the primary amino group is at 1284.4 cm -1 The peak at the center is the stretching vibration absorption peak of the phenolic hydroxyl group on the benzene ring; the analysis results are consistent with the structural formula of the DA monomer.

[0096] For PEGDA, 1635.4 cm -1 The absorption peak of carbon-carbon double bond is at 1616.9cm -1 The stretching vibration absorption peak of carbon-carbon double bond conjugation is at 2865.8cm -1 The peak at 1722.2 cm is the stretching vibration absorption peak of H in C-H of C=CH-; -1 The strong absorption peak of C=O in the carbonyl ester group is at 1097.3 cm -1 The stretching vibration absorption peak of the ether bond C—O—C is found; the analysis results are consistent with the expression of PEGDA monomer.

[0097] For DP, the analysis results show that 1635.4cm -1 1616.9cm -1 The absorption peak of the carbon-carbon double bond at 2865.8cm -1 The absorption peak of C-H in C=CH- is weakened because the carbon-carbon double bond disappears and other molecular bonds are generated; 1731.8cm -1 The strong absorption peak of C=O in the ester bond is offset compared with PEGDA, which is caused by the opening of the carbon-carbon double bond next to the ester group; 1604.5cm -1 The absorption peak at 1284.4 cm is mainly caused by C=C in the benzene ring structure, indicating that the amino group in DA is grafted onto the carbon chain; -1 The peak at 1016.3 cm is the stretching vibration absorption peak of the phenolic hydroxyl group on the DA benzene ring in DP; -1 The peak at the center is the stretching vibration absorption peak of the ether bond C—O—C. Its position is shifted to a lower wave number than that of PEGDA because its oxygen atoms form hydrogen bonds.

[0098] From the above analysis results, it can be seen that through the reaction of the present application, the catechol group was successfully introduced into DP, and the carbon-carbon double bond at the end of the PEGDA molecular chain was completely blocked, thereby preparing a functionalized polymer DP with a catechol group.

[0099] Experimental Test Example 2

[0100] The raw materials DA, PEGDA and the intermediate product DP were tested by nuclear magnetic resonance (NMR) instrument, and the solvent was deuterated dimethyl sulfoxide (DMSO-d6).

[0101] like Figure 7 As shown, the H NMR spectra of DA, PEGDA and DP were obtained ( 1 H NMR).

[0102] Among them, the chemical shift at about 2.5 ppm and the chemical shift at about 3.4 ppm are resonance peaks caused by water.

[0103] Depend on Figure 7 Analysis shows that the resonance peaks at chemical shifts of 8.86 ppm and 8.82 ppm in DA are attributed to the two protons (a and b) on the o-diphenol group; the resonance peak at a chemical shift of 7.83 ppm is attributed to the three protons (c) on the primary amino group, one of which comes from HCl; the resonance peaks with chemical shifts ranging from 6.47 ppm to 6.68 ppm are attributed to the three protons (d, e and f) on the benzene ring; the resonance peaks at chemical shifts of 2.67 ppm and 2.92 ppm are attributed to the protons in the methylene group close to the benzene ring (g) and far away from the benzene ring (h), respectively.

[0104] For PEGDA, the resonance peaks with chemical shifts ranging from 5.94 ppm to 6.36 ppm are attributed to the protons on the vinyl group (a, b, and c); the resonance peak with a chemical shift of around 4.2 ppm is attributed to the proton on the methylene group next to the ester group (d); and the resonance peak with a chemical shift ranging from 3.53 ppm to 3.66 ppm is attributed to the proton on the methylene group next to the ether bond.

[0105] For DP, the resonance peaks due to the protons in DA also appear in the 1H NMR spectrum of DP, but the resonance peaks due to the protons on the vinyl groups in PEGDA completely disappear. Furthermore, resonance peaks due to methylene protons on the main chain and side chains appear in the range of 2.51 ppm to 3.15 ppm. These analysis results further confirm that DP has a catechol structure and that DA is grafted onto the carbon-carbon double bond in PEGDA via amino groups. Furthermore, the absence of vinyl groups at the ends of the molecular chain indicates that the reaction between PEGDA and DA is complete, resulting in a catechol polymer (DP) with a high degree of polymerization, long molecular chain length, and superior mechanical properties.

[0106] Experimental Test Example 3

[0107] The raw materials TA, Gel, intermediate product DP and product DP@TA / Gel were tested by Fourier-transform infrared spectroscopy (FT-IR) in the wave number range of 4000-400 cm -1 .

[0108] like Figure 8 Shown are the FT-IR spectra of TA, Gel, DP and DP@TA / Gel.

[0109] For TA, the analysis results show that in the range of 3600-3000cm -1 The broad peak band in the range is due to the stretching vibration of O—H; 1697.1cm -1 The absorption peak at 1606.4 cm is caused by the C=O in the ester bond formed between the carboxyl group in tannic acid and the phenolic hydroxyl group; -1 The absorption peak at 1444.4 cm is mainly caused by C=C in the benzene ring structure; -1 and 1309.4cm -1 The absorption peaks at 1186.0 cm are caused by C—O and —OH in the phenolic hydroxyl structure; -1 The absorption peak at 1018.3 cm is caused by the C—O in the ester bond; -1 The absorption peak at is caused by the stretching vibration of the ether bond C—O—C; the analysis results are consistent with the structural formula of TA monomer.

[0110] For Gel, the analysis results show that 3278.5cm -1 and 3074.1cm -1 The absorption peak at 1627.7cm is mainly caused by the stretching vibration of N-H bond; -1 The stretching vibration absorption peak of C=O is at 1525.4cm -1 The absorption peak at 1236.2 cm is caused by the stretching vibration of the C-N bond and the bending vibration of the N-H bond; -1 The absorption peak at is mainly caused by the rocking vibration of the -CH2- group, the bending vibration of the N-H bond and the stretching vibration of the C-N bond; the analysis results are consistent with the structural formula of the Gel monomer.

[0111] For DP, the analysis results show that 2865.8cm -1 The absorption peak at 1731.8cm is formed by C—H in methylene; -1 The strong absorption peak of C=O in the ester bond is at 1604.5cm -1 The peak at 1284.4 cm is the vibration absorption peak caused by C=C in the benzene ring structure; -1 The stretching vibration absorption peak of the phenolic hydroxyl group -OH on the benzene ring is 1016.3cm -1 The peak is the stretching vibration absorption peak of the ether bond C—O—C.

[0112] For DP@TA / Gel, the analysis results show that the N—H bond in Gel is at 3278.5 cm -1 and 3074.1cm -1The stretching vibration peak at 2865.8 cm coincides with the —OH peak from DP and TA; -1 The absorption peak at 1716.4 cm comes from the C—H of the methylene in DP; -1 The C=O stretching vibration absorption peak is at 1606.4cm, which is slightly offset from DP, possibly due to the influence of intermolecular hydrogen bonding. -1 The absorption peak at 1531.2cm is mainly caused by the C=C in the benzene ring structure, which is present in both DP and TA. -1 The absorption peak at 1511.9 cm-1 coincides with the peak at that position in TA, which may be caused by the skeleton vibration of the benzene ring. -1 The weak peak at 1444.4 cm-1 may be related to the secondary amino group from Gel and is shifted to a lower wave number due to hydrogen bonding. -1 The absorption peak of C—O from the phenolic hydroxyl structure of TA is also retained at 1313.3 cm-1. However, due to the formation of a large number of hydrogen bonds and the overlap with the amino peak from Gel, the absorption peak of -OH in the phenolic hydroxyl group is moved to 1313.3 cm-1. -1 1187.9cm -1 The absorption peak at 754.1cm is the C—O bond of the ester bond in DP, TA and Gel. -1 The absorption peak at coincides with that of TA. This peak is a unique characteristic peak of TA and is presumably related to the out-of-plane swinging vibration of CH on the benzene ring.

[0113] From the above analysis results, it can be seen that through the reaction of the present application, DP, TA, and Gel are fully mixed, and the product DP@TA / Gel (bionic adhesive) having a skeleton Gel, a crosslinker TA, and a functionalized polymer DP containing a catechol group is prepared through a large number of hydrogen bond interactions.

[0114] Experimental Test Example 4

[0115] The raw material kaolinite and the products DP@TA / Gel, DP@TA / Gel-kao5, DP@TA / Gel-kao10, and DP@TA / Gel-kao15 were tested by Fourier-transform infrared spectrometer (FT-IR) in the wavenumber range of 4000-400 cm -1 .

[0116] like Figure 9 Shown are the FT-IR spectra of Kaolinite, DP@TA / Gel, DP@TA / Gel-kao5, DP@TA / Gel-kao10, and DP@TA / Gel-kao15.

[0117] For DP@TA / Gel, the analysis results show that 2865.8cm -1 The absorption peak at 1716.4 cm comes from C—H in methylene; -1 The stretching vibration absorption peak of C=O is at 1531.2cm -1 The absorption peak at 1511.9 cm-1 may be caused by the skeleton vibration of the benzene ring. -1 The weak peak at 1444.4 cm is related to the secondary amino group; -1 The absorption peak of C—O in the phenolic hydroxyl structure is at 1313.3 cm -1 The absorption peak of phenolic hydroxyl group -OH is at 1187.9 cm -1 The absorption peak at 754.1 cm is derived from the C—O bond of the ester bond; -1 The absorption peak at is related to the out-of-plane swinging vibration of CH on the benzene ring.

[0118] For Kaolinite, the analysis results show that 3687.4cm -1 The external -OH vibration absorption peak of octahedral coordination of kaolin is at 3619.9 cm -1 The -OH vibration absorption peak at the interface between the tetrahedron and the octahedron of the kaolin structural unit layer is 1002.8cm -1 The stretching vibration absorption peak of Si—O is at 910.3 cm -1 The bending vibration absorption peak of Al-OH is at 528.4 cm -1 、460.9cm -1 The peak at 2 is the bending vibration absorption peak of Si—O. The analysis results are consistent with the structural formula of Kaolinite.

[0119] For DP@TA / Gel-kao5, DP@TA / Gel-kao10, and DP@TA / Gel-kao15, the analysis results show that the hydroxyl peak of kaolin is 3687.4 cm -1 、910.3cm -1 There is a significant change in the composite material, shifting to 3693.2cm -1 and 914.2cm -1 The peak is formed by the external -OH and Al-O of the octahedral coordination formed by the aluminum element, indicating that the hydroxyl groups connected to the aluminum element in kaolin are added to DP@TA / Gel to form hydrogen bonds with its groups; 3619.9cm -1 The -OH vibration absorption peak on the interface between the tetrahedron sheet and the octahedron of the kaolin structural unit layer did not shift because the oxygen atoms inside the structure were difficult to be exposed to form hydrogen bonds with DP@TA / Gel; kaolin 1002.8cm -1、528.1cm -1 、460.9cm -1 The Si-OH characteristic peaks at 1006.7 cm-1 and 1006.7 cm-2 shifted to a certain extent. -1 、534.2cm -1 、466.7cm -1 This indicates that the -OH group connected to silicon in kaolin also forms a bond with DP@TA / Gel, thus affecting the peak positions of -OH and Si-O. At the same time, by comparing the characteristic peaks of DP@TA / Gel and DP@TA / Gel-kao15, it can be seen that the peak at 2865.8cm in DP@TA / Gel is -1 、1187.9cm -1 The peak at 2875.5 cm -1 、1186.0cm -1 It indicates that chemical bonding occurred during the combination of DP@TA / Gel and kaolin.

[0120] From the above analysis results, it can be seen that in the composite hemostatic materials of this application (DP@TA / Gel-kao5, DP@TA / Gel-kao10, DP@TA / Gel-kao15), kaolin and the molecular network of DP@TA / Gel form a chemical bond rather than just a physical mixture, so the composite glue exhibits better mechanical strength and adhesion properties.

[0121] Experimental Test Example 5

[0122] DP@TA / Gel, DP@TA / Gel-kao1, DP@TA / Gel-kao2, DP@TA / Gel-kao5, DP@TA / Gel-kao10 and DP@TA / Gel-kao15 were tested by X-ray diffraction (XRD), and the test 2θ range was 5-60 degrees.

[0123] like Figure 10 As shown in the figure, as the proportion of kaolin increases, its characteristic peaks become more obvious. The peak at 2θ=8.4° in the DP@TA / Gel spectrum is mainly related to the residual triple helical structure of the gelatin component in DP. In addition, the broad peak at 2θ=20.9° is formed by the full scattering of DP@TA / Gel, which also suggests that with the increase of the proportion of kaolin, the peak shifts to 2θ=21.3°. It is speculated that after the addition of kaolin, it is inserted into the polymer network, causing the tertiary structure of gelatin to open during the secondary gelation process, and the hydroxyl groups in kaolin connected to aluminum and silicon elements form hydrogen bonds with the nitrogen atoms in the amino and imino groups in the polymer chain.

[0124] Experimental Test Example 6

[0125] Swelling rate test

[0126] Detection method: Before the test, take out a centrifuge tube and weigh its mass (G0), place a certain amount of DP@TA / Gel-kao hemostatic powder in the centrifuge tube, use phosphate buffered saline (PBS, pH=7.4) as the test liquid, add a certain amount of PBS to the centrifuge tube to allow the hemostatic powder to fully gel, then immediately suck out the PBS with a syringe, and carefully remove excess water on the surface of the material with absorbent paper, and weigh the mass of the centrifuge tube at this time (G1). After adding enough PBS to the centrifuge tube, place it in a constant temperature water bath shaker at 37°C. Take out the centrifuge tube after 1, 3, 6, 12, and 24 hours, suck out the PBS with a syringe, and carefully remove excess water on the surface of the hemostatic material with absorbent paper, and weigh the mass of the centrifuge tube at this time (G t The swelling ratio (Swellingratio) of hemostatic powder is calculated using the following formula:

[0127] Swelling ratio = (G t -G1+G0) / (G1-G0)×100%

[0128] Among them, t=1, 3, 6, 12, 24.

[0129] Test results and analysis: Figure 11 As shown in Figure 2, the swelling rates of DP@TA / Gel-kao hemostatic materials with different kaolin contents were soaked in PBS for different times. Figure 11 It can be seen that throughout the swelling process, all materials reached maximum swelling at 1 hour, then slowly decreased to a minimum with increasing immersion time. Hemostatic materials with higher kaolin content experienced greater swelling rates, but all materials swelled only slightly throughout the swelling process, ultimately reaching a negative value, demonstrating the excellent anti-swelling properties of the DP@TA / Gel-kao hemostatic material. Swelling due to water absorption reduces the material's cohesion, thereby reducing its adhesion. This anti-swelling property ensures that the adhesive hemostatic material does not fall off due to swelling when absorbing water.

[0130] The reason for this is that kaolin is hygroscopic, which increases the water absorption and swelling rate of the composite hemostatic material containing kaolin. At the same time, the bionic adhesive (DP@TA / Gel) absorbs water to form a gel, which is cross-linked through strong hydrogen bonds, and can inhibit the overall water absorption capacity of the material to a certain extent, so that the above materials only swell slightly and finally reach a negative value. Therefore, the interaction between the bionic adhesive and kaolin makes the composite hemostatic powder (DP@TA / Gel-kao) have excellent anti-swelling properties. At the same time, the composite hemostatic powder will not reduce the cohesion of the material due to swelling when stopping bleeding in a humid / underwater environment, so that it has a better adhesion effect.

[0131] Experimental Test Example 7

[0132] Adhesion testing

[0133] The lap shear test was used to determine the shear strength of the hemostatic material and to analyze the adhesion strength of the hemostatic powder.

[0134] The specific method involves using pigskin as the adhesive substrate and testing the adhesion strength of different hemostatic materials using an axial shear tensile test. Fresh pigskin was cut into 20mm x 30mm rectangles and bonded to a 20mm x 100mm Pi (polyimide) sheet using 502 glue. A certain amount of deionized water was added to the hemostatic material to allow it to fully gel. The material was then evenly applied to the fresh pigskin bonded to the Pi sheet. The material was exposed to air for 10 minutes to cure. Another piece of pigskin was then placed on top and pressed firmly for 10 seconds to ensure full contact between the pigskin and the hemostatic material. The Pi sheet was then clamped securely and tensile tested using a universal mechanical testing machine at a rate of 50mm / min. The load-displacement curve was recorded. Adhesion strength was calculated by dividing the load by the adhesion area. Three replicates were performed for each sample group.

[0135] Test results and analysis: Figure 12 The figure shows the adhesion curve of the DP@TA / Gel-kao hemostatic material with different kaolin contents on fresh pig skin as the adhesion strength changes with the tensile displacement. Figure 12It can be seen that different kaolin contents have a great influence on the adhesion of hemostatic materials. Among them, the maximum adhesion strengths of DP@TA / Gel, DP@TA / Gel-kao1, and DP@TA / Gel-kao2 are all around 2.5 kPa, and the overall trend is that the adhesion strength increases slightly with the increase in the proportion of kaolin added, but the difference in adhesion is not large; the maximum adhesion strength of DP@TA / Gel-kao5 shows a significant decrease (around 1.6 kPa); then, the adhesion strength of DP@TA / Gel-kao10 and DP@TA / Gel-kao15 shows a significant jump, which is significantly better than other groups. The maximum adhesion strength of DP@TA / Gel-kao10 is around 5 kPa, and the maximum adhesion strength of DP@TA / Gel-kao15 is around 5.5 kPa. The results show that when the mass proportion of kaolin in the composite hemostatic material is 10%~15%, it has excellent adhesion and is significantly better than the bionic adhesive (DP@TA / Gel). When used for hemostasis, it can achieve a more stable physical closure of the wound, and thus can continuously exert coagulation function at the wound, thereby improving the efficiency of hemostasis.

[0136] Experimental Test Example 8

[0137] Liquidity testing

[0138] Test method: A Haake rotational rheometer was used to characterize the rheological properties of the composite hemostatic material after gelation. First, a certain amount of deionized water was added to the hemostatic powder to allow it to fully gel. Then, a certain amount of hemostatic material was drawn up with a syringe and injected onto a circular flat-bottomed metal sample table with a diameter of 20 mm. After evenly spreading the material, the height of the clamp was adjusted so that the hemostatic material filled the space between the sample table and the clamp. The height between the clamp and the sample table was set to 0.5 mm, and the temperature was set to room temperature. The hemostatic material was subjected to an Osc oscillation amplitude sweep test to obtain the storage modulus (G') and loss modulus (G") at different strains. The test conditions were set as follows: strain range 0.1% to 1000%, constant oscillation frequency 1 Hz.

[0139] Test results and analysis: Figure 13 The figure shows the storage modulus (G') and loss modulus (G") of the composite hemostatic material under different strains after absorbing water and forming a gel. The storage modulus, also known as the elastic modulus, can indicate the amount of energy stored in the material during elastic deformation and can be used to analyze the elasticity of the material. When the G' value of the material is greater than the G" value, the material tends to be solid. The loss modulus, also known as the viscous modulus, can indicate the amount of energy lost in the material during viscous deformation and can be used to analyze the viscosity of the material. When the G" value of the material is greater than the G' value, the material tends to be liquid.

[0140] Depend on Figure 13It can be seen that the G' and G" values ​​of DP@TA / Gel-kao hemostatic powders with different kaolin ratios after absorbing water to form gels show a trend of first being stable and then gradually decreasing with the increase of strain, indicating that DP@TA / Gel-kao hemostatic powders can withstand a certain strain and remain stable. Elasticity and viscosity will decrease due to high-intensity strain. Within the entire test range, the G" value of DP@TA / Gel-kao hemostatic powders with different kaolin ratios is greater than the G' value, indicating that the hemostatic powders become liquid-like materials after absorbing water to form gels. The reason is that after the hemostatic powders are gelled, they mainly rely on the action of hydrogen bonds for cross-linking, and the degree of cross-linking is weak. Liquid-like materials have a certain fluidity, which allows the hemostatic material to spread better on the tissue surface and come into closer contact with the tissue, which helps to generate stronger adhesion between the hemostatic material and the tissue, enhance the adhesion effect, and improve the hemostatic ability.

[0141] Experimental Test Example 9

[0142] The porcine femoral artery rupture model was used to evaluate the hemostatic properties of the materials DP@TA / Gel, DP@TA / Gel-kao5, DP@TA / Gel-kao10, and DP@TA / Gel-kao15.

[0143] The experimental groups are shown in Table 2.

[0144] Table 2 Grouping of the porcine femoral artery rupture model hemostasis evaluation experiment

[0145]

[0146] Surgical Preparation: On the day of surgery, pigs were premedicated with buprenorphine (0.025 mg / kg) for analgesia and glyconolate (0.01 mg / kg) to reduce salivation and block vagal bradycardia. Anesthesia was performed with 5% isoflurane oxygen via face mask. The pigs were then intubated and mechanically ventilated with 100% oxygen. Tidal volume and ventilation were adjusted to maintain an end-tidal carbon dioxide pressure of 40 mmHg ± 2 mmHg.

[0147] Surgical procedures: see Figure 14 As shown in center a, an approximately 10 cm incision is made in the groin. After the abductor femoris muscles are parted to expose the femoral artery, a 5 cm section of the artery is dissected from adjacent tissue to avoid damaging the adjacent femoral vein and nerve. To prevent vasospasm and dilate the artery to its normal diameter, the artery is soaked in 3 mL of 2% lidocaine in gauze for 10 minutes.

[0148] See also Figure 14 As shown in b and c, the proximal and distal ends of the exposed artery are clamped with hemostatic forceps, the artery is lifted up with forceps, and a 4 mm incision is made on the anterior surface of the blood vessel with a scalpel, and a small amount of blood flowing out of the closed blood vessel is wiped off.

[0149] Cut an opening in the hemostatic material bag encapsulated in a polyvinyl alcohol water-soluble film bag to ensure that the material can come into direct contact with the damaged blood vessel and blood. Use the hemostatic material / control group material to accurately cover the vascular wound site and surrounding tissue. Loosen the hemostatic clamps on both sides, add weighed gauze and start pressing for two minutes.

[0150] The treated pig legs were bent and stretched five times to simulate walking to test the hemostatic stability of the material.

[0151] Experimental results: see Figure 16 As shown, the commercial kaolin hemostatic gauze group (Group E) used three hemostatic gauze pieces, requiring approximately 10 minutes to achieve hemostasis, resulting in approximately 20.9 g of blood loss. The group without hemostatic material (Group F) took approximately 15 minutes to achieve hemostasis, resulting in approximately 153.2 g of blood loss. After surgery, the control group's material was slowly removed, but some blood oozing was still visible within the wound.

[0152] Compared with the control group, the hemostasis time of each material group (Groups A, B, C, and D) was significantly shortened, and all achieved immediate hemostasis after pressure application, with no blood seepage observed. Specifically, the DP@TA / Gel group (Group A), DP@TA / Gel-kao5 (Group B), DP@TA / Gel-kao10 (Group C), and DP@TA / Gel-kao15 group (Group D) all achieved immediate hemostasis after pressure application, meaning no blood seepage was observed after the hemostatic pack was applied to the wound. After hemostasis was complete, the hemostatic pack was removed, revealing a certain degree of adhesion between the material and the pig tissue. Figure 15 As shown in the image, after hemostasis, the hemostatic bag inside the wound showed no obvious adhesion to the surrounding tissue, and there was no excess blood or clots. After surgery, the hemostatic bag was removed, and a small amount of powder directly contacted the arterial rupture to maintain adhesion, preventing excess blood from spurting or seeping out of the arterial rupture.

[0153] In summary, the biomimetic adhesive and kaolin in the composite hemostatic material (DP@TA / Gel-kao) are cross-linked through hydrogen bonds, and have good anti-swelling properties. In a humid / underwater environment, hemostasis will not reduce the cohesion of the material due to swelling, and has a good adhesion effect; the composite hemostatic material with a kaolin content of 10%-15% has better adhesion strength and good adhesion performance; after the composite hemostatic material absorbs water and forms a gel, it exhibits the properties of a liquid material, and can fully and closely contact with the adhesion matrix, resulting in a better adhesion effect; the composite hemostatic material (DP@TA / Gel-kao15) has excellent hemostatic properties, can achieve instant physical closure by rapid adhesion to the wound, and at the same time quickly achieve coagulation by initiating a hemostatic cascade reaction through the material, which synergistically can achieve rapid hemostasis of arterial bleeding.

Claims

1. A composite hemostatic material, characterized in that: The composite hemostatic material comprises a biomimetic adhesive and kaolin, wherein the biomimetic adhesive is compounded by catechol polymer, tannic acid and gelatin; The catechol polymer is prepared by Michael addition reaction of polyethylene glycol diacrylate and dopamine hydrochloride; The mass proportion of the kaolin is 10% to 15%; When preparing the biomimetic adhesive, a tannic acid solution is added to a catechol polymer, and stirring and mixing is started immediately after the tannic acid solution is added. After thorough mixing, a gelatin solution is added and continued to be stirred quickly and thoroughly to precipitate a gel to obtain a biomimetic adhesive. The biomimetic adhesive is freeze-dried and crushed to obtain a biomimetic adhesive powder. The composite hemostatic material is prepared by mixing the powder of the biomimetic adhesive with kaolin powder, adding water and stirring to form a gel, freeze-drying, and crushing the mixture. The crushed mixture is then loaded into a polyvinyl alcohol water-soluble film bag. The biomimetic adhesive and kaolin in the composite hemostatic material are cross-linked through hydrogen bonds.

2. The composite hemostatic material according to claim 1, characterized in that: The dopamine hydrochloride is grafted to the carbon-carbon double bond at the end of the polyethylene glycol diacrylate via an amino group.

3. The composite hemostatic material according to claim 2, characterized in that: The catechol polymer does not contain a vinyl group.

4. The composite hemostatic material according to claim 2, characterized in that: The biomimetic adhesive is prepared by mixing catechol polymer, 10 w / v% gelatin solution and 20 w / v% tannic acid solution in a volume ratio of 3:2:

8.

5. A method for preparing the composite hemostatic material according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, weigh dopamine hydrochloride and polyethylene glycol diacrylate, add dimethyl sulfoxide, and stir until dissolved into a transparent clear solution; S2, adding triethylamine to adjust the pH to alkaline; S3, after heating and reacting for 2 hours, dopamine hydrochloride was added until it was excessive, and the reaction was continued for 1 hour. The filtrate was filtered and collected, and the filtrate was washed with methyl tert-butyl ether. After standing and stratification, the upper liquid was removed, and the methyl tert-butyl ether was removed in a vacuum drying oven to obtain a catechol polymer; S4, respectively weighing gelatin and tannic acid to prepare gelatin solution and tannic acid solution; S5, stirring and mixing the catechol polymer, gelatin solution and tannic acid solution to prepare a biomimetic adhesive; S6, freeze-drying and crushing the biomimetic adhesive; S7, mixing the crushed biomimetic adhesive powder with kaolin powder to prepare a composite hemostatic material precursor; S8, taking the composite hemostatic material precursor, adding water, stirring to form a gel, freeze-drying, and crushing to obtain a composite hemostatic material.

6. The method for preparing the composite hemostatic material according to claim 5, characterized in that: Also includes one or more of the following conditions: Steps S1, S2 and S3 are all carried out in the absence of light and under nitrogen protection; In step S5, the catechol polymer and tannic acid solution are first mixed evenly, and then the gelatin solution is added and stirred to prepare a biomimetic adhesive; In step S8, the mass ratio of the composite hemostatic material precursor to water is 1:5; In step S8, the obtained composite hemostatic material is sealed in a polyvinyl alcohol water-soluble film bag to obtain a composite hemostatic material product.

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