Sprayable medical hydrogel and application thereof

Abstract

The invention relates to a sprayable medical hydrogel and application thereof, the injectable medical hydrogel comprises a first component and a second component, the first component comprises chitosan or chitosan oligosaccharide with high deacetylation degree or a derivative thereof, and the second component comprises chitosan with high deacetylation degree or chitosan oligosaccharide with high deacetylation degree or chitosan oligosaccharide with high deacetylation degree or chitosan oligosaccharide with high deacetylation degree or chitosan oligosaccharide with high deacetylation degree; the second component is one of aldehyde group terminated multi-arm polyethylene glycol or succinimide terminated multi-arm polyethylene glycol; the medical hydrogel is absorbable medical hydrogel formed by in-situ crosslinking after a first component and a second component are subjected to bi-component injection physical mixing. The medical hydrogel can be used for sealing wounds of injured parts of dura mater or spinal cord; the temperature-sensitive hydrogel overcomes the defects of slow curing time and low gel strength of temperature-sensitive hydrogel, can be polymerized without open ultraviolet irradiation, and is suitable for in-vivo injection.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and more specifically, to a sprayable medical hydrogel for sealing the dura mater or spinal cord and its uses. Background Technology

[0002] Hydrogels are three-dimensional networks formed by the chemical or physical cross-linking of hydrophilic polymer chains. They can absorb water effectively but remain insoluble in water, swelling significantly while maintaining their original three-dimensional structure. Hydrogels contain a large amount of water (up to 90%), are soft, shape-variable, and have physical properties similar to biological tissues. They exhibit excellent biocompatibility, can load different materials, and have extremely high compatibility. Furthermore, their mechanical properties are tunable, making them an excellent class of biomaterials. They are widely applicable in many fields such as environmental engineering, flexible sensing, and electrochemistry, especially in the biomedical field, including tissue engineering, drug delivery systems, wound dressings, biosensors, and contact lenses.

[0003] Commonly used hydrogels are thermosensitive hydrogels and photosensitive hydrogels. Thermosensitive hydrogels need to be injected into the body in liquid form at low temperatures and gradually solidify into a gel at body temperature. However, thermosensitive hydrogels have disadvantages such as slow curing speed and low gel strength because they do not undergo chemical cross-linking, and their mechanical properties cannot meet the requirements for hydrogel adhesives, sealants, and in-situ isolation. Photosensitive hydrogels, on the other hand, require external light to induce hydrogel formation in the presence of a photoinitiator, as illustrated in, for example, Chinese patent document CN. Item 106543454A discloses a photopolymerizable polyethylene glycol hydrogel. However, this type of photosensitive hydrogel requires open ultraviolet light irradiation to initiate polymerization, making it unsuitable for closed-cell intravenous injection. This solution employs a two-component injection technique to inject the two liquid components that form the hydrogel into the body, where they undergo an in-situ chemical reaction and cross-linking to form the hydrogel. This overcomes the shortcomings of thermosensitive hydrogels, such as slow curing time and low gel strength due to the lack of chemical cross-linking. Furthermore, polymerization can occur without open ultraviolet light irradiation, making it suitable for intravenous injection. Additionally, given the high swelling rate of current hydrogels, which can easily absorb water and swell to compress nerves during surgical closure of traumatic brain injury and peripheral nerve injury, the two-component hydrogel in this solution has a low swelling rate, preventing nerve compression caused by swelling. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a sprayable medical hydrogel for sealing the dura mater or spinal cord and its uses, so as to solve the technical problems mentioned in the background art.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] A sprayable medical hydrogel, wherein the first component comprises highly deacetylated chitosan or chitosan oligosaccharide or derivatives thereof, wherein the chitosan derivatives include, but are not limited to, chitosan hydrochloride, carboxymethyl chitosan, hydroxypropyl chitosan methacryloylated carboxymethyl chitosan, and hydroxyethyl deacetylated chitosan, and wherein the chitosan oligosaccharide derivatives include, but are not limited to, chitosan oligosaccharide hydrochloride, and the second component is at least one of aldehyde-terminated multi-arm polyethylene glycol or succinimidyl-terminated multi-arm polyethylene glycol.

[0007] Preferably, the chitosan in the first component has a degree of deacetylation of at least 80%, and more preferably a degree of deacetylation of 99%.

[0008] Preferably, the molecular weight of chitosan in the first component is 10kDa-100kDa, more preferably 50kDa.

[0009] Preferably, the degree of polymerization of the chitosan oligosaccharide in the first component can be any chitosan oligosaccharide or a mixture of multiple chitosan oligosaccharides between 2 and 20.

[0010] Preferably, the chitosan or chitosan oligosaccharide or derivatives thereof in the first component can be of plant or animal origin.

[0011] Preferably, the second component is selected from aldehyde-terminated multi-arm polyethylene glycol or succinimide-terminated multi-arm polyethylene glycol, with at least two polyethylene glycol arms, preferably four-arm polyethylene glycol and eight-arm polyethylene glycol.

[0012] Preferably, the second component is selected from aldehyde-terminated multi-arm polyethylene glycol or succinimide-terminated multi-arm polyethylene glycol, and the molecular weight of the multi-arm polyethylene glycol is 1kDa-100kDa, preferably 10kDa-20kDa.

[0013] Preferably, the hydrogel is prepared by dissolving the first component in a 1% acetic acid solution or physiological saline to form a first solution, dissolving the second component in physiological saline to form a second solution, and then mixing the first solution and the second solution through a two-component injection system to obtain a medical hydrogel.

[0014] Preferably, the molar ratio of active functional groups in the first component and the second component is 1:1.

[0015] Preferably, the hydrogel can be used for wound sealing at sites of dura mater or spinal cord injury.

[0016] Compared with the prior art, the present invention has the following outstanding features:

[0017] 1. The first and second components used in this invention have a short gelation time after mixing, and gel can be formed in situ within 3-20 seconds after mixing;

[0018] 2. The absorbable medical hydrogel of the present invention has a low swelling rate and will not cause significant swelling that compresses nerves;

[0019] 3. The medical hydrogel of the present invention has good biodegradability in vivo, and the in vivo degradation and absorption time can be adjusted by changing the component ratio;

[0020] 4. The surgical site is sealed by injection or spraying, avoiding the pain and cost associated with surgical implantation;

[0021] 5. The injectable medical hydrogel of the present invention is simple to operate, and both the raw materials and the product are non-toxic.

[0022] This patent uses chitosan or chitosan oligosaccharide and multi-arm polyethylene glycol as raw materials. Chitosan is a product of chitin, a natural polysaccharide, by removing some acetyl groups. It has various physiological functions such as biodegradability, biocompatibility, non-toxicity, antibacterial properties, anticancer effects, lipid-lowering effects, and immune enhancement. It is widely used in food additives, textiles, agriculture, environmental protection, beauty and health care, cosmetics, antibacterial agents, medical fibers, medical dressings, artificial tissue materials, drug sustained-release materials, gene transduction vectors, biomedical fields, medical absorbable materials, tissue engineering carrier materials, medical and drug development, and many other fields and daily chemical industries. Chitosan oligosaccharide is produced by the depolymerization of chitosan and is an upgraded product of chitin and chitosan products. This product possesses unparalleled advantages over chitosan. Prepared using advanced enzymatic hydrolysis, chitosan oligosaccharides exhibit advantages such as low molecular weight, high water solubility, significant functional effects, easy absorption by the human body, and high bioactivity. Furthermore, it is characterized by being purely natural, radiation-free, pollution-free, and additive-free. Polyethylene glycol, a polymer of ethylene oxide hydrolysis products, is non-toxic and non-irritating, and widely used in various pharmaceutical preparations. Four-armed and eight-armed polyethylene glycols polymerized with pentaerythritol and trimerpentaerythritol as cores are widely used in the preparation of hydrogel materials. These hydrogels have various applications in medical devices and regenerative medicine, particularly suitable for drug sustained release, 2D and 3D cell culture, and wound sealing and healing. Attached Figure Description

[0023] Figure 1 A delivery device for two-component hydrogels;

[0024] Figure 2 This is the molecular structural formula of chitosan;

[0025] Figure 3 The molecular structural formula of chitosan;

[0026] Figure 4 The molecular structural formula of chitosan is shown below.

[0027] Figure 5 The molecular structural formula of chitosan;

[0028] Figure 6 The molecular structure of aldehyde-terminated four-arm polyethylene glycol (4ARM-PEG-CHO);

[0029] Figure 7 The molecular structure of aldehyde-terminated eight-arm polyethylene glycol (8ARM-PEG-CHO);

[0030] Figure 8 The molecular structure of succinimide-terminated four-arm polyethylene glycol (4ARM-PEG-NHS);

[0031] Figure 9 The molecular structure of succinimide-terminated eight-arm polyethylene glycol (8ARM-PEG-NHS);

[0032] Figure 10 This is an image of the medical hydrogel prepared in Example 1;

[0033] Figure 11 This is an image of the medical hydrogel prepared in Example 2;

[0034] Figure 12 This is an image of the medical hydrogel prepared in Example 3;

[0035] Figure 13 This is an image of the medical hydrogel prepared in Example 4;

[0036] Figure 14 This is an image of the medical hydrogel prepared in Example 9;

[0037] Figure 15 This is an image of the medical hydrogel prepared in Example 11;

[0038] Figure 16 This is an image of the medical hydrogel prepared in Example 13;

[0039] Figure 17 This is an image of the medical hydrogel prepared in Example 15;

[0040] Figure 18 This is an image of the medical hydrogel prepared in Example 17;

[0041] Figure 19 MRI image of the medical hydrogel of Example 10 implanted subcutaneously in the leg of a rat;

[0042] Figure 20 Pathological staining image of the medical hydrogel of Example 10 implanted subcutaneously in the leg of a rat 7 days later;

[0043] Figure 21Pathological staining image of the medical hydrogel of Example 10 implanted subcutaneously in the leg of a rat 14 days later;

[0044] Figure 22 Pathological staining image of the medical hydrogel of Example 10 implanted subcutaneously in the leg of a rat 21 days later. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] A sprayable medical hydrogel and its uses are disclosed. Specifically, the first component is dissolved in a 1% acetic acid solution or physiological saline to form a first solution, and the second component is dissolved in physiological saline to form a second solution. The first and second solutions are then mixed using a two-component delivery system to obtain the medical hydrogel. A three-dimensional view of the mentioned two-component delivery system is shown below. Figure 1 More specifically, depending on the needs of the injection site, a coating nozzle can be connected to the Y-type connector of the two-component injection system. The first component is dissolved in a 1% acetic acid solution or physiological saline to form a first solution, and the second component is dissolved in physiological saline to form a second solution. The first and second component solutions are respectively drawn into two syringes, which are assembled in the two-component delivery system. During the injection process, the first and second component solutions flow through the Y-type connector and are mixed in the coating nozzle connected to the Y-type connector. They are then applied to the surgical site to seal the surgical wound.

[0047] Based on the above scheme, to gain a more specific understanding of the optimal performance of the hydrogel, the following more detailed preparation examples were conducted, wherein the molecular structure diagram of chitosan is shown in the figure. Figure 2 As shown, it contains a large number of amino groups; the molecular structure diagram of chitosan is shown below. Figure 3 As shown, it contains three amino groups; the molecular structure diagram of chitosan is shown below. Figure 4 As shown, it contains five amino groups; the molecular structure diagram of chitosan is shown below. Figure 5 As shown, it contains seven amino groups.

[0048] Example 1

[0049] According to the molar ratio of active functional groups of the first component to the second component being 1:1, 66.8 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 13.36 mg / mL; 1000 mg of aldehyde-terminated tetraarm polyethylene glycol (4ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0050] Example 2

[0051] According to the molar ratio of active functional groups of the first component to the second component being 1:1, 33.4 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a 6.68 mg / mL solution of the first component; 1000 mg of aldehyde-terminated tetraarm polyethylene glycol (4ARM-PEG-CHO-20K, molecular weight 20000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a 200 mg / mL solution of the second component; the first and second component solutions were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0052] Example 3

[0053] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 133.6 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 26.72 mg / mL; 1000 mg of aldehyde-terminated octane polyethylene glycol (8ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0054] Example 4

[0055] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 66.8 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 13.36 mg / mL; 1000 mg of aldehyde-terminated octane polyethylene glycol (8ARM-PEG-CHO-20K, molecular weight 20000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0056] Example 5

[0057] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 66.8 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 13.36 mg / mL; 1000 mg of succinimide-terminated tetraarm polyethylene glycol (4ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0058] Example 6

[0059] According to the molar ratio of active functional groups of the first component to the second component being 1:1, 33.4 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a 6.68 mg / mL solution of the first component; 1000 mg of succinimide-terminated tetraarm polyethylene glycol (4ARM-PEG-NHS-20K, molecular weight 20000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a 200 mg / mL solution of the second component; the first and second component solutions were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0060] Example 7

[0061] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 133.6 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 26.72 mg / mL; 1000 mg of succinimide-terminated octahedral polyethylene glycol (8ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0062] Example 8

[0063] According to the molar ratio of active functional groups of the first component to the second component being 1:1, 66.8 mg of chitosan (molecular weight 501 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 13.36 mg / mL; 1000 mg of succinimide-terminated octahedral polyethylene glycol (8ARM-PEG-NHS-20K, molecular weight 20000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first and second component solutions were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0064] Example 9

[0065] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 131.84 mg of chitosan (molecular weight 824 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 26.37 mg / mL; 1000 mg of aldehyde-terminated octane polyethylene glycol (8ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0066] Example 10

[0067] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 131.84 mg of chitosan (molecular weight 824 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 26.37 mg / mL; 1000 mg of succinimide-terminated octahedral polyethylene glycol (8ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0068] Example 11

[0069] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 130.97 mg of chitosan (molecular weight 1146 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 26.19 mg / mL; 1000 mg of aldehyde-terminated octahedral polyethylene glycol (8ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0070] Example 12

[0071] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 130.97 mg of chitosan (molecular weight 1146 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a first component solution of 26.19 mg / mL; 1000 mg of succinimide-terminated octahedral polyethylene glycol (8ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0072] Example 13

[0073] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 129.6 mg of chitosan (degree of deacetylation 99%, average molecular weight 50 kDa) was dissolved in 5 mL of 1% acetic acid solution to prepare a first component solution of 25.92 mg / mL; 1000 mg of aldehyde-terminated octane polyethylene glycol (8ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0074] Example 14

[0075] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 129.6 mg of chitosan (99% degree of deacetylation, average molecular weight 50 kDa) was dissolved in 5 mL of 1% acetic acid solution to prepare a first component solution of 25.92 mg / mL; 1000 mg of succinimide-terminated octahedral polyethylene glycol (8ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0076] Example 15

[0077] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 172.8 mg of chitosan (degree of deacetylation 75%, average molecular weight 50 kDa) was dissolved in 5 mL of 1% acetic acid solution to prepare a first component solution of 34.56 mg / mL; 1000 mg of aldehyde-terminated octane polyethylene glycol (8ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0078] Example 16

[0079] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 172.8 mg of chitosan (degree of deacetylation 75%, average molecular weight 50 kDa) was dissolved in 5 mL of 1% acetic acid solution to prepare a first component solution of 34.56 mg / mL; 1000 mg of succinimide-terminated octahedral polyethylene glycol (8ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0080] Example 17

[0081] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 259.2 mg of chitosan (degree of deacetylation 50%, average molecular weight 50 kDa) was dissolved in 5 mL of 1% acetic acid solution to prepare a first component solution of 51.84 mg / mL; 1000 mg of aldehyde-terminated octane polyethylene glycol (8ARM-PEG-CHO-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0082] Example 18

[0083] According to the molar ratio of active functional groups of the first component to the second component of 1:1, 259.2 mg of chitosan (degree of deacetylation 50%, average molecular weight 50 kDa) was dissolved in 5 mL of 1% acetic acid solution to prepare a first component solution of 51.84 mg / mL; 1000 mg of succinimide-terminated octane polyethylene glycol (8ARM-PEG-NHS-10K, molecular weight 10000 g / mol) was dissolved in 5 mL of physiological saline with pH 7.2 to prepare a second component solution of 200 mg / mL; the first component solution and the second component solution were extruded in equal amounts through a duplex mixer to form a medical hydrogel.

[0084] The detection method for the above-prepared medical hydrogel is as follows:

[0085] S1. Determination of gel solidification time: Dissolve the first component in 1% acetic acid solution or physiological saline to form the first solution, and dissolve the second component in physiological saline to form the second solution. Then, mix the first solution and the second solution through a two-component delivery system and inject them into a preheated thermostat at 37°C. Start timing immediately after the gel is injected until hydrogel is formed (by picking up the gel with a syringe needle) and record the gelation time.

[0086] S2. Swelling Rate (%) Detection: The swelling rate refers to the percentage increase in mass of the hydrogel during the swelling process in phosphate buffer after cross-linking and curing. The first component is dissolved in 1% acetic acid solution or physiological saline to form a first solution, and the second component is dissolved in physiological saline to form a second solution. The first and second solutions are then mixed using a two-component injection system and injected into a cylindrical cavity mold with an inner diameter of 10 mm and a height of 10 mm to form a cylindrical hydrogel with a diameter of 10 mm and a height of 10 mm. The hydrogel sample is accurately weighed and transferred to a petri dish, which is then immersed in preheated 37°C neutral phosphate buffer. The petri dish is placed in a 37°C incubator. Every 5 minutes, the hydrogel sample is removed, and surface moisture is absorbed with filter paper. The weight of the sample after water absorption is measured until the weight of the hydrogel sample no longer increases. The gel swelling rate is calculated using the following formula:

[0087]

[0088] S3: Mechanical property test: The first component is dissolved in 1% acetic acid solution or physiological saline to form a first solution, and the second component is dissolved in physiological saline to form a second solution. Then, the first solution and the second solution are mixed through a two-component injection system and injected into a cylindrical cavity mold with an inner diameter of 10 mm and a height of 10 mm to form a cylindrical hydrogel with a diameter of 10 mm and a height of 10 mm. The hydrogel sample is removed and placed in the compression test module of an electronic universal testing machine (INSTRON5982, USA) to test the force-displacement curve, stress-strain curve, compressive strength and compressive modulus of the hydrogel.

[0089] S4: In vitro degradation test: The first component is dissolved in 1% acetic acid solution or physiological saline to form the first solution, and the second component is dissolved in physiological saline to form the second solution. The first and second solutions are then mixed through a two-component delivery system and injected into a cylindrical cavity mold with an inner diameter of 10 mm and a height of 10 mm to form a cylindrical hydrogel with a diameter of 10 mm and a height of 10 mm. The hydrogel sample is then removed and immersed in neutral phosphate buffer at 37°C. The hydrogel is observed daily until it is no longer visible to the naked eye, and this is recorded as the in vitro degradation time of the hydrogel.

[0090] S5: In vivo safety test: Adult male SD rats were used as experimental animals to test the biotoxicity of the medical hydrogel via subcutaneous implantation. Rats were anesthetized with isoflurane gas and fixed in a prone position on the operating table. Leg hair was shaved and disinfected with iodine and ethanol. The first component was dissolved in 1% acetic acid solution or physiological saline to form a first solution, and the second component was dissolved in physiological saline to form a second solution. The first and second solutions were then mixed using a two-component delivery system and injected subcutaneously into the rat's leg tissue via an injection needle. Tissue samples were taken at different time points for pathological sectioning and staining to observe the effects of the hydrogel on the tissue.

[0091] The test data of the medical hydrogels prepared in Examples 1 to 8 were compared according to the above test methods as follows:

[0092] Table 1. Comparison of the properties of medical hydrogels prepared with different second-component polyethylene glycol.

[0093]

[0094]

[0095] Special Note:

[0096] 1. The second component used in Examples 1 and 2 is aldehyde-terminated four-arm polyethylene glycol (4ARM-PEG-CHO), with the molecular structure as follows: Figure 6 As shown;

[0097] 2. The second component used in Examples 3 and 4 is aldehyde-terminated eight-arm polyethylene glycol (8ARM-PEG-CHO), with the molecular structure as follows: Figure 7 As shown;

[0098] 3. The second component used in Examples 5 and 6 is succinimide-terminated four-arm polyethylene glycol (4ARM-PEG-NHS), with the molecular structure as follows: Figure 8 As shown;

[0099] 4. The second component used in Examples 7 and 8 is succinimide-terminated eight-arm polyethylene glycol (8ARM-PEG-NHS), with the molecular structure as follows: Figure 9 As shown.

[0100] Through experimental comparison:

[0101] The medical hydrogel prepared in Example 1 has the following appearance: Figure 10 As shown, it is a colorless and transparent hydrogel that can maintain its shape and is a soft gel.

[0102] The medical hydrogel prepared in Example 2 has the following appearance: Figure 11 As shown, it is a colorless and transparent hydrogel that can barely maintain its shape and is a viscous gel.

[0103] The medical hydrogel prepared in Example 3 has the following appearance: Figure 12 As shown, it is a colorless and transparent hydrogel that can be molded and has good elasticity and toughness;

[0104] The medical hydrogel prepared in Example 4 has the following appearance: Figure 13 As shown, it is a colorless and transparent hydrogel that can be molded and has good elasticity, but its elasticity and toughness are significantly weaker than those of Example 3.

[0105] The medical hydrogel prepared in Example 5 has a similar appearance and properties to that in Example 1;

[0106] The medical hydrogel prepared in Example 6 has a similar appearance and properties to that in Example 2;

[0107] The medical hydrogel prepared in Example 7 has a similar appearance and properties to that in Example 3;

[0108] The medical hydrogel prepared in Example 8 has a similar appearance and properties to that in Example 4.

[0109] By comparing Examples 1 and 2, 3 and 4, 5 and 6, and 7 and 8, it can be determined that when the second component uses PEG with the same number of arms, the higher the molecular weight, the longer the gel curing time, the higher the swelling rate, the shorter the degradation time, and the weaker the mechanical properties.

[0110] Based on the data comparison of the medical hydrogels in Examples 1 and 3, 2 and 4, 5 and 7, and 6 and 8, it can be determined that, for the same molecular weight of the second component, the medical hydrogel prepared by eight-arm polyethylene glycol has a shorter gel solidification time, lower swelling rate, longer in vitro degradation time, and stronger mechanical properties compared to four-arm polyethylene glycol. The reason for this is that, for the same molecular weight, polyethylene glycol with more arms has a higher concentration of active groups, a faster reaction rate with chitosan, more chemical bonds formed, a shorter hydrogel formation time, and higher strength.

[0111] By comparing Examples 1 and 5, Examples 2 and 6, Examples 3 and 7, and Examples 4 and 8, it can be determined that when the second component uses PEG with the same number of arms and molecular weight, compared with aldehyde-terminated polyethylene glycol, succinimide-terminated polyethylene glycol generally reacts with chitosan to form a hydrogel in a shorter time and reacts faster, indicating that succinimide groups have a faster reactivity with amino groups.

[0112] The test data of the medical hydrogels prepared in Examples 3, 7, and 9 to 12 were compared according to the above test methods as follows:

[0113] Table 2 Comparison of the properties of medical hydrogels prepared with different first-component chitosan oligosaccharides

[0114]

[0115]

[0116] Through experimental comparison:

[0117] The medical hydrogel prepared in Example 9 has the following appearance: Figure 14As shown, it is a colorless, opaque hydrogel that can be molded and has good elasticity and toughness;

[0118] The medical hydrogel prepared in Example 11 has the following appearance: Figure 15 As shown, it is a colorless, opaque hydrogel that can be molded and has good elasticity and toughness;

[0119] The medical hydrogel prepared in Example 10 has a similar appearance and properties to that in Example 9;

[0120] The medical hydrogel prepared in Example 12 has a similar appearance and properties to that in Example 11;

[0121] Comparing Examples 3, 9 and 11, and Examples 7, 10 and 12, it can be determined that, under the condition that the second component is the same, there is no significant difference in the gelation time, swelling ratio, in vitro degradation time and mechanical properties of the hydrogels formed by chitosan, chitopentose and chitoheptaose with the second component.

[0122] The test data of the medical hydrogels prepared in Examples 13 to 18 were compared according to the above test methods as follows:

[0123] Table 3 Comparison of the properties of medical hydrogels prepared with different first-component chitosan

[0124]

[0125] Through experimental comparison:

[0126] The medical hydrogel prepared in Example 13 has the following appearance: Figure 16 As shown, it is a pale yellow, transparent hydrogel that can maintain its shape and is a soft gel.

[0127] The medical hydrogel prepared in Example 15 has the following appearance: Figure 17 As shown, it is a pale yellow, transparent hydrogel that cannot maintain its shape and is a viscous gel.

[0128] The medical hydrogel prepared in Example 17 has the following appearance: Figure 18 As shown, it is a pale yellow, transparent hydrogel that cannot maintain its shape and is a viscous gel.

[0129] The medical hydrogel prepared in Example 14 has a similar appearance and properties to that in Example 13;

[0130] The medical hydrogel prepared in Example 16 has a similar appearance and properties to that in Example 15;

[0131] The medical hydrogel prepared in Example 18 has a similar appearance and properties to that in Example 17;

[0132] Comparing Examples 13, 15 and 17, and Examples 14, 16 and 18, as the degree of chitosan deacetylation decreased, the gelation time of the medical hydrogel was significantly prolonged, the swelling rate was significantly increased and the compression modulus was reduced, and the in vitro degradation time gradually decreased.

[0133] Comparing Examples 13 and 14, 15 and 16, and 17 and 18, it can be seen that, under the same degree of chitosan deacetylation in the first component, there are no significant differences in gel time, swelling ratio, in vitro degradation time, and mechanical properties between the hydrogels formed by aldehyde-terminated polyethylene glycol and succinimide-terminated polyethylene glycol and the first component.

[0134] Based on the comparison of physical properties of each embodiment, the hydrogel formed by chitosan oligosaccharide and the second component showed significantly better physical parameters than the hydrogel formed by chitosan and the second component. The performance of Example 10 was significantly superior to the other embodiments. The medical hydrogel prepared in Example 10 was injected subcutaneously into the leg of rats to observe its biocompatibility and MRI imaging effects. Figure 19 As shown, in Example 10, the medical hydrogel injected into the subcutaneous tissue 24 hours later could be imaged on MRI, revealing the location of the hydrogel. Figure 20-22 As shown, pathological section staining of medical hydrogel injected into subcutaneous tissue in Example 10 for 7, 14 and 21 days showed no obvious inflammatory reaction in the tissue surrounding the hydrogel, indicating that the hydrogel has excellent biocompatibility.

[0135] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto; any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A sprayable medical hydrogel, characterized in that: The first component comprises chitosan or chitosan oligosaccharide with a high degree of deacetylation, or derivatives thereof, wherein the chitosan derivatives include, but are not limited to, chitosan hydrochloride, carboxymethyl chitosan, hydroxypropyl chitosan methacryloylated carboxymethyl chitosan, and hydroxyethyl deacetylated chitosan, and the chitosan oligosaccharide derivatives include, but are not limited to, chitosan oligosaccharide hydrochloride. The second component is at least one of aldehyde-terminated multi-arm polyethylene glycol or succinimide-terminated multi-arm polyethylene glycol.

2. The sprayable medical hydrogel according to claim 1, characterized in that: The degree of deacetylation of chitosan in the first component is at least 80%, preferably 99%.

3. The sprayable medical hydrogel according to claim 1, characterized in that: The molecular weight of chitosan in the first component is 10kDa-100kDa, preferably 50kDa.

4. The sprayable medical hydrogel according to claim 1, characterized in that: The degree of polymerization of the chitosan oligosaccharide in the first component can be any chitosan oligosaccharide or a mixture of multiple chitosan oligosaccharides between 2 and 20.

5. The sprayable medical hydrogel according to claim 1, characterized in that: The chitosan or chitosan oligosaccharide or derivatives thereof in the first component may be of plant or animal origin.

6. The sprayable medical hydrogel according to claim 1, characterized in that: The second component is selected from aldehyde-terminated multi-arm polyethylene glycol or succinimide-terminated multi-arm polyethylene glycol, with at least two polyethylene glycol arms, preferably four-arm polyethylene glycol and eight-arm polyethylene glycol.

7. The sprayable medical hydrogel according to claim 1, characterized in that: The second component is selected from aldehyde-terminated multi-arm polyethylene glycol or succinimide-terminated multi-arm polyethylene glycol, with a molecular weight of 1kDa-100kDa, preferably 10kDa-20kDa.

8. The sprayable medical hydrogel according to claim 1, characterized in that: The hydrogel is prepared by dissolving the first component in a 1% acetic acid solution or physiological saline to form a first solution, dissolving the second component in physiological saline to form a second solution, and then mixing the first solution and the second solution through a two-component injection system to obtain a medical hydrogel.

9. The sprayable medical hydrogel according to claim 1, characterized in that: The molar ratio of active functional groups in the first component and the second component is 1:

1.

10. The sprayable medical hydrogel according to claim 1, characterized in that: Hydrogels can be used to seal wounds at sites of dura mater or spinal cord injury.

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