A ROS-responsive controllable drug release hydrogel with high tensile and high viscosity, a preparation method and applications thereof

Abstract

The present application relates to the field of biomaterial technology and medical product technology, and particularly relates to a reactive and active oxygen scavenging drug-releasing hydrogel, a preparation method and application thereof. The hydrogel prepared by the present application uses nicotinamide prodrugs as non-covalent cross-linking agents and free radical polymerization to provide a hydrogel skeleton, and has the characteristics of flexible change of gel physical properties, so it has multiple uses, and the proven uses include cutting wounds, wound surfaces and various scenes with active oxygen level surge. Compared with traditional materials, the flexible physical shape change ability, strong adhesion and excellent tensile capacity have significant advantages for application in irregular wound scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomaterials and medical products, in particular to a ROS-responsive controllable drug release hydrogel with high stretchability and high adhesion, a preparation method and applications thereof. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general context of the present application and does not necessarily constitute an admission that this information forms part of the prior art already known in this field.

[0003] Wounds refer to the damage of skin or mucosa integrity caused by trauma, infection, surgery or chronic diseases, which may involve subcutaneous tissue or even deep structures. Clinically, the damage of skin barrier is considered to increase the risk of pathogen invasion, leading to local infection or systemic sepsis. In addition, wound pain and scar contracture can cause dysfunction, such as limited joint movement. Chronic wounds can consume nutrients and increase metabolic burden, and even induce osteomyelitis or systemic inflammatory response.

[0004] The field of skin wound repair has long been faced with core challenges such as insufficient mechanical properties of traditional dressings, weak environmental responsiveness and uncontrollable drug release. Although hydrogels have advantages over traditional dressings in avoiding secondary damage caused by drying, high water absorption to maintain wound moisture and accelerate healing, and adding functional components to endow hydrogels with specific properties, existing hydrogel materials have physical performance defects such as rigid network structure that is difficult to adapt to skin dynamic activities (such as joint bending and muscle stretching), low elastic modulus, easy breakage and poor adhesion. In addition, the single function and lack of active response to pathological signals in the wound microenvironment also make the drug release out of sync with the healing process, which is a problem in the use of hydrogels in tissue repair. Therefore, hydrogel materials with high adhesion and stretchability to firmly adhere to damaged tissues to adapt to tissue dynamic activities and respond to pathological signals for intelligent drug release have become an important research direction in the repair of damaged tissues.

[0005] The trigger-stimulus-responsive hydrogel can provide targeted drug release as needed, which has great application potential for intelligent improvement of treatment effect and promotion of personalized medicine. The phenylboronic ester bond is a suitable cross-linking bond for hydrogel, which is a reversible reaction between phenylboronic acid and cis-diol. When applied in hydrogel, it can endow the hydrogel with a dynamic reversible cross-linking network, ROS responsiveness and intelligent drug control release ability, so that it can play multiple roles in wound healing: the high adhesion provided by the phenylboronic ester can more easily combine with the skin, closely adhere to irregular wounds through the self-repairing property, and reduce mechanical damage; dynamically release drugs in response to the ROS microenvironment of the wound (such as infection or inflammation state), synergistically inhibit infection, remove active oxygen and promote skin recovery; its biomimetic flexible structure supports tissue remodeling, while the degradation product has good biocompatibility.

[0006] The nucleophilic substitution reaction between the pyridine ring of nicotinamide and 4-bromomethylphenylboronic acid can respond to ROS. After protonation of pyridine, the positive and negative charges can be connected to provide a non-covalent cross-linking agent for the hydrogel, which can significantly improve the ductility of the hydrogel. When this bond is applied in the hydrogel and broken to release drugs in response to ROS, it can dynamically respond to the active oxygen microenvironment.

[0007] In the early stage of skin trauma (24-72 hours), the infiltration of neutrophils and macrophages leads to a sharp increase in local ROS concentration, providing a specific trigger signal for intelligent drug release. By embedding ROS-sensitive nicotinamide prodrugs into the hydrogel network, ROS concentration-dependent drug control release can be achieved: maintaining structural stability in normal tissues, while dynamic bonds break in inflammatory areas to release nicotinamide directionally. Compared with traditional enzyme-responsive systems, the ROS-sensitive mechanism does not depend on specific enzyme expression levels, and can accurately match the ROS concentration gradient of different types of trauma (acute cuts, chronic ulcers), thereby optimizing the synchronization of drug release kinetics and repair progress.

[0008] In the context of the rapid rise of minimally invasive surgery today, the demand for multifunctional, easy-to-use hydrogel functional dressings in clinical practice has become particularly urgent. SUMMARY

[0009] In view of the deficiencies of the prior art, the purpose of the present application is to provide a hydrogel material that can respond to and remove active oxygen and release drugs, and a preparation method thereof. The hydrogel is mainly composed of polyvinyl alcohol and acrylamide and 2-acrylamido-2-methylpropanesulfonic acid copolymer, and the nicotinamide prodrug forms cross-linking points with polyvinyl alcohol and covalent cross-linking chains through the formation of phenylboronic ester bonds and the connection of positive and negative charges to form a hydrogel. The hydrogel has the advantages of strong adhesion, ultra-high stretchability and good biocompatibility. Combining these properties, the material is suitable for wound healing. The core of the design of the hydrogel lies in the synergistic optimization of the dynamic cross-linking network and the biomimetic adhesion mechanism to solve the multiple contradictions in the skin attachment scenario.

[0010] The technical solutions adopted by the present application are as follows:

[0011] In the first aspect of the present application, a ROS-responsive drug-controlled and high-stretching and high-viscosity hydrogel is provided, which uses nicotinamide prodrug (NP) as a non-covalent crosslinking agent to bridge polyvinyl alcohol (PVA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS); on this basis, a covalent crosslinking network is formed through the thermal initiation copolymerization of AMPS and acrylamide (AM), thereby constructing a stable double-crosslinked hydrogel skeleton.

[0012] The present application designs a biomimetic double network structure: 1) a rigid skeleton composed of covalently crosslinked polyacrylamide, providing initial mechanical support; 2) a flexible energy dissipation layer composed of dynamic non-covalent interactions (phenylboronic acid ester bonds, positive and negative charge connections), absorbing deformation energy through reversible bond rupture, endowing the material with tear resistance and rapid rebounding ability and self-repairing ability, significantly prolonging the service life of the material in a dynamic wound.

[0013] In the second aspect of the present application, a preparation method of the ROS-responsive drug-controlled and high-stretching and high-viscosity hydrogel is provided, which comprises the following steps:

[0014] S1, dissolve 2-acrylamido-2-methylpropanesulfonic acid (AMPS) in water and fully dissolve;

[0015] S2, neutralize the solution obtained in step S1 to maintain the pH value at weak alkaline;

[0016] S3, add polyvinyl alcohol (PVA) and acrylamide (AM) to the solution obtained in step S2, heat and stir until completely dissolved;

[0017] S4, add nicotinamide prodrug (NP) to the solution obtained in step S3, stir and dissolve; wherein the structure of NP is ;

[0018] S5, dissolve N,N'-methylenebisacrylamide (MBA) and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] in water and fully dissolve;

[0019] S6, add the solution obtained in step S5 to the solution of step S4 in a set proportion and mix uniformly;

[0020] S7, fill the mixed solution prepared in step S6 with nitrogen to exclude oxygen, and then perform thermal initiation polymerization to form a double-crosslinked hydrogel.

[0021] Further, the mass concentration of AMPS in the solution obtained in S1 is 3-8%, preferably 5%.

[0022] Further, the weak alkaline environment in S2 is to provide suitable reaction conditions for the benzene borate ester bond, and the alkaline pH is generally controlled at about 8 (7.5-8.5).

[0023] Further, the mass concentration of PVA in the solution obtained in S3 is 5-15%, and the mass concentration of AM is 5-15%.

[0024] In S4, the NP is a prior art and can be obtained by those skilled in the art.

[0025] The method in CN120504685A can be used to prepare.

[0026] Further, the mass concentration of the nicotinamide prodrug in the solution obtained in S4 is 0%-25%, not including 0%, and the physical properties of the gel can be dynamically changed by changing the amount of the prodrug according to different application scenarios.

[0027] In S4, (1) In addition to the certain efficacy of nicotinamide itself, the nicotinamide prodrug also has the advantages of low raw material price and high synthesis yield. (2) As a drug-loaded water gel, the nicotinamide prodrug has a drug function and also has a structure function of gelation: 1) The benzene borate ester bond of the nicotinamide prodrug can be connected with polyvinyl alcohol. 2) The protonated pyridine of the nicotinamide prodrug can be connected with a long chain of a poly radical with a negative charge. Based on this, a crosslinking site between the two long chains can be formed. (3) Since both crosslinking sites have ROS response characteristics, the crosslinking site after gelation can provide the gel with the characteristic of ROS response. (4) Both crosslinking methods are non-covalent crosslinking, which can bring high adhesion and high tensile properties to the gel. In addition to the effect of the drug itself, the treatment of the wound also mainly utilizes the physical effect of the water gel material, on the one hand, the wound is adhered without suturing, and on the other hand, the drug also plays a role in antioxidant and antibacterial.

[0028] Further, the mass concentration of MBA in the solution obtained in S6 is 0.03-0.08%, preferably 0.05%; and the mass concentration of 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] is 0.05-0.15%, preferably 0.1%.

[0029] Further, in S7, the polymerization reaction time is 10-15 h, preferably 12 h; and the reaction temperature is 90-95°C.

[0030] In a third aspect of the present application, the ROS-responsive controllable drug release water gel with high tensile and high adhesion is used in the preparation of a drug or dressing for repairing cut wounds, scratches or various wounds.

[0031] Furthermore, the wound is a linear wound repair and / or a facial wound repair.

[0032] Compared with the related technologies known to the inventors, one of the technical solutions of the present invention has the following beneficial effects:

[0033] (1) The advantages of this invention are that the preparation process is simple, all raw materials are commercially available, the required synthetic monomers have high yields and are easy to purify, and the hydrogel materials are easy to prepare on a large scale and promote in the market.

[0034] (2) The ROS-responsive hydrogel provided by this invention has a wide range of applications. After gelation, the hydrogel exhibits strong universal adhesion and excellent extensibility, and different viscoelasticities can be imparted to the hydrogel depending on the amount of raw materials, making it suitable for various application scenarios. Proven implementation examples include: 1) wound adhesives, which can replace medical sutures to close wounds and promote healing; 2) surface-type wound dressings, which serve as multifunctional dressings to cover and heal wounds. This invention is particularly suitable for daily use and has significant value and importance for emergency treatment of everyday accidental injuries.

[0035] (3) The polyvinyl alcohol used in this invention is a pharmaceutical excipient approved by the U.S. Food and Drug Administration (FDA), which has low biotoxicity, good biocompatibility, and is safe to use. At the same time, due to the medicinal value of nicotinamide itself, it can also play a role in improving function after wound repair. Attached Figure Description

[0036] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] Figure 1 : Schematic diagram of a hydrogel that can respond to and remove reactive oxygen species and release drugs (A) Chemical molecular structure of each component of the hydrogel; (B) Macroscopic view of the hydrogel before and after gelation; (C) Microscopic view of the hydrogel after gelation; (D) Rheological properties of each component of the hydrogel.

[0038] Figure 2 : Schematic diagram of the gelation mechanism of hydrogel that can respond to and eliminate reactive oxygen species. (A) Comparison of prodrug and prodrug reacting with polyvinyl alcohol 1H NMR spectrum; (B) Infrared spectrum of each component of hydrogel and after gelation; (C) Stretching properties of hydrogel in different salt environments; (D) Verification of hydrogel synthesis strategy by precipitation of positive and negative charge polymers.

[0039] Figure 3 Effects of prodrugs as non-covalent crosslinking agents and covalent crosslinking agents on the swelling rate of hydrogels (A) Effects of prodrug grouping on the swelling rate of hydrogels (B) Effects of covalent crosslinking agent grouping on the swelling rate of hydrogels

[0040] Figure 4 : Mechanical properties of ROS-responsive and ROS-scavenging hydrogels. (A) Tensile stress-strain of hydrogel prodrug group; (B) Tensile stress-strain of hydrogel covalent crosslinker group; (C) Compressive stress-strain of hydrogel prodrug group.

[0041] Figure 5 : Adhesion properties of ROS-responsive and ROS-scavenging hydrogels. (A) Macroscopic view of adhesion properties; (B) Shear adhesion of prodrug group.

[0042] Figure 6 : Self-healing properties of ROS-responsive and ROS-scavenging hydrogels. (A) Macroscopic view of hydrogel self-healing; (B) Cyclic strain analysis in rheology; (C) Microscopic self-healing of hydrogel.

[0043] Figure 7 : ROS response and drug release of ROS-responsive and ROS-scavenging hydrogels. (A) Molecular formula of prodrug response to ROS decomposition; (B) NMR hydrogen spectrum detection of prodrug response to ROS; (C) Zeta potential of prodrug before and after response to ROS; (D) Zeta potential of prodrug and polyvinyl alcohol solution before and after response to ROS; (E) UV spectrum of prodrug hydrogel response to ROS over time; (F) High performance liquid chromatography of prodrug hydrogel response to ROS over time.

[0044] Figure 8 : ROS scavenging ability of ROS-responsive and ROS-scavenging hydrogels. (A) ABTS antioxidant capacity of hydrogel prodrug group; (B) Fluorescence map of hydrogel prodrug group after co-culture with H2O2.

[0045] Figure 9 : Biocompatibility of ROS-responsive and ROS-scavenging hydrogels. (A) Compatibility of hydrogel prodrug group to L929 cells; (B) Hemolysis level of hydrogel prodrug group.

[0046] Figure 10 : Tissue adhesive application of ROS-responsive and ROS-scavenging hydrogels. (A) Macroscopic view of hydrogel body repairing linear wound; (B) Femtosecond detection of skin sample after hydrogel body repairing linear wound; (C) HE staining and Masson staining after hydrogel body repairing linear wound.

[0047] Figure 11 : Wound repair application of ROS-responsive and ROS-scavenging hydrogels. (A) Macroscopic view of hydrogel body repairing wound; (B) Schematic diagram of hydrogel body repairing wound; (C) Healing rate of wound repair over time; (D) HE staining and Masson staining after hydrogel body repairing linear wound. DETAILED DESCRIPTION

[0048] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0049] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0050] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific examples.

[0051] First, the main raw materials and experimental equipment required by the present application are described in detail.

[0052] Experimental instruments: electronic balance, ultrasonic mixer, magnetic stirrer, pH meter, oil bath, water purification system, pipette, nitrogen device.

[0053] Experimental drugs:

[0054] Nicotinamide, 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), and polyvinyl alcohol (PVA, degree of hydrolysis: 98.0-99.0 mol%, viscosity: 5.2-6.0 mPa.s) were purchased from Aldrich. Acrylamide (AM), N,N'-methylenebisacrylamide (MBA), 4-(bromomethyl)phenylboronic acid, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) were purchased from Alfa Aesar. Sodium hydroxide was provided by SCR Ltd. Nicotinamide prodrug (NP) was prepared according to the method in Example 1 of CN120504685A.

[0055] Example 1, preparation of a drug-releasing hydrogel that can respond to and clear reactive oxygen species

[0056] The target product is obtained by cross-linking the copolymer of polyvinyl alcohol and AM and AMPS using the method of using nicotinamide prodrug as cross-linking agent (the specific chemical structure is shown in the following Figure 1 A). It has the following steps:

[0057] S1, prepare a 50mg / 950μL AMPS solution;

[0058] S2, use NaOH to neutralize the solution to pH 8;

[0059] S3, 100 mg PVA and 100 mg AM were weighed in a 5 mL vial, 950 μL AMPS solution was added, and the two substances were dissolved by stirring at 80°C. Homogenization was performed;

[0060] S4, 0, 5, 10, 15, 20, and 25 mg of nicotinamide prodrug were weighed after homogenization and added to 950 μL of the solution obtained in S3. The mixture was stirred until it became clear. The products were named NPH0, NPH5, NPH10, NPH15, NPH20, and NPH25, respectively, according to the amount of prodrug.

[0061] S5, a small amount of solution containing 1 mg MBA / 100 μL and 2.2 mg 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide) / 100 μL was prepared;

[0062] S6, 40 μL of the solution obtained in S6 was added to the solution obtained in S4, and the mixture was stirred and purged with nitrogen to remove air. The reaction was carried out at 90°C overnight to obtain NPH Figure 1 B, Figure 1 C). In rheology, the storage modulus and loss modulus of NPH were tested Figure 1 D), which showed that as the amount of NP increased, the storage modulus of NPH gradually approached the loss modulus, and the gel tended to be more liquid. This was due to the fact that NP as a non-covalent crosslinking agent caused the gel to gradually lose the covalent crosslinking rigidity of free radical polymerization.

[0063] Example Two, Principle of Drug-Release Hydrogel Responsive to and Clearing Reactive Oxygen Species

[0064] The generation of phenylboronic ester and the linkage of positive and negative charges were verified to prove the successful synthesis of NPH (see Figure 2 ). NP and NP with PVA were detected by nuclear magnetic resonance hydrogen spectrum in weak base to verify the successful generation of phenylboronic ester bond (see Figure 2 A). The results showed that the H peak shifted at a specific position, which was due to the strong electron-withdrawing inductive effect of the alkoxy group caused by the formation of the phenylboronic ester bond, which directly reduced the electron cloud density of the benzene ring, causing the hydrogen on the benzene ring and the connecting group to move to a high field, proving that the phenylboronic ester bond existed in the system at room temperature. In the FTIR spectrum (see Figure 2In B), the B-O bond in NP appears at 1388 cm-1, while in the prodrug gel, the B-O bond appears at 1308 cm-1, due to the increase in the coordination number of the B-O bond, the lengthening of the bond, the formation of the phenylboronic ester bond leading to a decrease in vibration frequency and red shift, also proving the successful connection of the phenylboronic ester bond in the prodrug hydrogel. NPH15 was added to a gradient concentration of NaCl before gelling, and the system was subjected to tensile stress-strain testing in the presence of different concentrations of salt solution, 0, 200, 400, 600 mM. The results show that as the concentration of salt solution increases, the tensile properties of the hydrogel show a weakening trend, which is due to the increase in salt, which introduces a large number of positive and negative electrons Na + and Cl - occupies the original pyridine protonation and sulfonic acid anion group linking site, reducing the non-covalent linking of positive and negative charges, the ability to dissipate external force, and reducing the tensile properties of the gel. When the long chain of the polymer with positive property charge meets the long chain of the negative ion, uneven aggregation occurs, resulting in sedimentation. Based on this, AMPS and AM were polymerized into a long-chain precursor solution with negative electric property, which dissolved PVA, and when it was added to a high-concentration NP solution, white flocculent sedimentation occurred, which was attributed to the addition of NP with a protonated pyridine structure to the solution containing PVA, which quickly connected to form a long-chain structure with positive electric property through a phenylboronic ester bond. When the long chains of the two properties are mixed, the uneven aggregation of the two presents a white flocculent phenomenon (Fig. 6D), confirming the successful linking of positive and negative charges in the system. Figure 2

[0065] Example Three, Mechanical property test of drug release hydrogel that can respond to and scavenge reactive oxygen species

[0066] In the swelling properties of the hydrogel ( Figure 3 ), when the amount of NP increased from 0 to 5 mg, 15 mg, 25 mg, the swelling rate of the gel increased from 384.2% to 462.4%, 516.5%, 541.8%, respectively, while the amount of MBA changed from 1 to 2, 3, 4, the swelling rate of the hydrogel decreased from 602.2% to 440.0%, 402.8%, 365.5%, which can show that the non-covalent crosslinking agent NP brings the dissipation mechanism to the gel at the same time can make the gel network loose, but the introduction of MBA can strengthen the covalent crosslinking to dynamically adjust the physical properties of the hydrogel. Figure 4 In the stress-strain experiment of the gel ( Figure 4 ​C) When the NP concentration increases, the slope of the compression stress-strain curve decreases, which means the decrease of the Young's modulus of the gel. To enhance the strength of the gel in different scenarios, we choose to introduce covalent crosslinker MBA to strengthen the covalent crosslinking network, Figure 4 B) When the amount of MBA increases, the gel shows a trend of gradually becoming hard but brittle.

[0067] Example Four: Adhesion of the ROS-responsive and ROS-removing hydrogel

[0068] The phenylboronic ester bond itself has good adhesion, and through the reversible crosslinking, the hydrogel can better fit the surface microstructure by adjusting the local structure such as the breaking and recombination of dynamic bonds when it contacts the surface, increasing the effective contact area and strengthening the interfacial interaction. The shear adhesion force (SAF) of the hydrogel is measured by the shear adhesion test. Figure 5 B) When the amount of NP increases, the shear adhesion force of the material gradually increases, and when NP is equal to 20 mg, the shear stress reaches 295 KPa, but when the content is 25 mg, the value decreases to 276 KPa. This phenomenon is due to the low strength of the gel at high NP, which causes the gel itself to break before reaching the maximum adhesion force. When testing the adhesion of NPH to various objects, Figure 5 A), NPH also shows wide adhesion properties on various materials.

[0069] Example Five: Self-healing properties of the ROS-responsive and ROS-removing hydrogel

[0070] After connecting different batches of gels, different gel repair phenomena occur Figure 6 A), due to the connection between positive and negative charges and the non-covalent reversible bond of the phenylboronic ester bond, which can be reconnected after breaking, which is reflected in the macroscopic self-healing of the gel. In the rheological analysis Figure 6 B), it can be seen that the gel breaks down when G' is less than G'' in the high strain region, and when it is converted to low strain, G' is greater than G'', and the repair phenomenon occurs. Under the microscope, the gel is cut with a scalpel Figure 6 C), 8 min after the crack repair.

[0071] Example Six: Response and drug release of the ROS-responsive and ROS-removing hydrogel

[0072] When NPH is in an active oxygen environment, the NP acting as a crosslinking agent will respond to ROS to decompose and release functional molecules such as nicotinamide and biocompatible degradation substances Figure 7A), and the corresponding hydrogen spectrum peaks of the two substances were shown, proving the successful response reaction. Zeta potential detection was performed before and after the ROS response of NP, and it could be seen that the state changed from positive to negative, because the pyridine protonation of NP itself would provide a positive potential, and after the response, the pyridine protonation was reduced, and the NP was decomposed into nicotinamide, and the conjugated π electron system of the pyridine ring could make the surface present weak negative electric nature by adsorbing OH⁻ ions in water. Based on this, the Zeta potential detection of the mixed solution of NP and PVA was performed, and the results showed the same trend, proving that when NP and PVA were connected to form a phenylboronic acid ester bond, the decomposition of NP would still occur to break the connection with PVA. When NPH was placed in the ROS environment, the UV analysis spectrum showed that the absorbance of the corresponding peak increased Figure 7 E). Further, high performance liquid chromatography analysis of the time change leaching solution after ROS response of NPH showed that the gel continuously released nicotinamide in six hours, and could not effectively release the drug in the absence of active oxygen.

[0073] Example Seven: Active oxygen scavenging capacity test of active oxygen scavenging and responsive drug release hydrogel

[0074] ABTS antioxidant experiment was performed on NPH in the group Figure 8 A), which showed that after introducing NP, ABTS free radicals were efficiently scavenged. After L929 cells were co-cultured with hydrogen peroxide and different groups of NPH culture medium leaching solution, fluorescence staining was performed Figure 8 B), and by comparing the negative and positive groups, it could be seen that the green fluorescence representing active oxygen damage weakened with the increase of NP, indicating that the active oxygen scavenging capacity gradually improved.

[0075] Example Eight: Biocompatibility of active oxygen scavenging and responsive drug release hydrogel

[0076] The L929 cells were co-cultured with the leaching solution extracted from the NPH in the group, and the absorbance after 24h and 48h was detected by a microplate reader Figure 9 A), and by formula processing, the L929 cells after co-culturing with the leaching solution showed similar proliferation as the control cells without leaching solution, verifying the good cell compatibility of NPH. Hemolysis level analysis was performed on different groups of NPH Figure 9 B), and it was found that NPH in different groups had good hemolysis level, and the hemolysis level of the gel gradually became better with the increase of NP.

[0077] Example Nine: Application of active oxygen scavenging and responsive drug release hydrogel as an adhesive

[0078] Healthy 3-month-old male Kunming mice were selected. After anesthetizing with isoflurane gas, the fur on the back of the mice was removed, and a linear incision of approximately 1 cm in length was created on the back of the mice using a scalpel to simulate a surgical incision. The control group underwent wound treatment with sutures, while the experimental group had their wounds sealed with NPH. The mice in both groups were observed at different time points. Figure 10 A), was euthanized seven days later for testing. The femtosecond laser testing results showed ( Figure 10 (B) In the gel treatment group, the dermis showed a good growth trend, complete closure of the dermis, and abundant collagen fibers. In HE staining, the control group showed dense nuclei arranged along the wound, indicating an inflammatory response to acute injury. The experimental group showed no significant inflammatory response, demonstrating that NPH promotes wound healing and counteracts inflammatory responses caused by injury. NPH is easy to use in wound incisions, prevents secondary damage from suturing in mice, and promotes full-thickness development, showing great potential for clinical application.

[0079] Example 10: Application of responsive and reactive oxygen-releasing hydrogels in skin defects

[0080] Healthy male SD rats weighing 300g were selected. After anesthetizing the rats with isoflurane gas, the fur on their backs was removed, and circular marks of equal area were made. Then, circular full-thickness skin of equal thickness was removed using scissors to create a dorsal wound. The control group received no treatment, while the experimental group had their wounds sealed with NPH dressings. Rats in both groups were observed at different time points. Figure 11 A), the mice were sacrificed two weeks later for testing. After integrating the wound images of the backs of the two groups of mice at different time points, the recovery rate of the wound area was calculated using a formula. Figure 11 B). The results showed that the NPH group exhibited a significant healing-promoting function compared to the control group. In pathological staining, the epidermis in the control group was incompletely healed and discontinuous, with red staining in the dermis and slow collagen fiber formation. In the experimental group, the epidermis healed continuously, and homogeneous new collagen fibers appeared in the dermal regeneration area, indicating that the experimental group had a better healing speed and quality than the control group, demonstrating the value of NPH in wound healing applications.

[0081] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A ROS-responsive, controllable drug release hydrogel with high stretch and high viscosity, characterized in that, The nicotinamide prodrug is used as a non-covalent crosslinking agent to bridge polyvinyl alcohol and 2-acrylamido-2-methylpropanesulfonic acid; on this basis, a covalent crosslinking network is formed through a thermal initiation copolymerization reaction between 2-acrylamido-2-methylpropanesulfonic acid and acrylamide, so as to construct a stable double-crosslinked hydrogel skeleton; The hydrogel is prepared by the following method: S1, 2-acrylamido-2-methylpropanesulfonic acid is dissolved in water and fully dissolved; S2, the solution obtained in step S1 is neutralized, and the pH value is maintained at weak alkaline; S3, polyvinyl alcohol and acrylamide are added to the solution obtained in step S2, heated and stirred until completely dissolved; S4, nicotinamide prodrug is added to the solution obtained in step S3, and stirred and dissolved; wherein the structure of the nicotinamide prodrug is ; S5, N,N'-methylene bisacrylamide and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] are dissolved in water and fully dissolved; S6, the solution obtained in step S5 is added to the solution in step S4 in a set proportion, and mixed uniformly; S7, the mixed solution prepared in step S6 is filled with nitrogen to exclude oxygen, and then a thermal initiation polymerization reaction is carried out to form a double-crosslinked hydrogel; In the solution obtained in S1, the mass concentration of 2-acrylamido-2-methylpropanesulfonic acid is 3-8%; In the solution obtained in S3, the mass concentration of polyvinyl alcohol is 5-15%, and the mass concentration of acrylamide is 5-15%; In the solution obtained in S4, the mass concentration of nicotinamide prodrug is 0%-25%, excluding 0%; In the solution obtained in S6, the mass concentration of N,N'-methylene bisacrylamide is 0.03-0.08%, and the mass concentration of 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] is 0.05-0.15%.

2. The method for preparing a ROS-responsive, controllable drug release and high-stretch, high- viscosity hydrogel according to claim 1, wherein the step of polymerizing the monomer solution is performed at a temperature of 4 to 40°C for 1 to 10 hours. The method comprises the following steps: S1, 2-acrylamido-2-methylpropanesulfonic acid is dissolved in water and fully dissolved; S2, the solution obtained in step S1 is neutralized, and the pH value is maintained at weak alkaline; S3, polyvinyl alcohol and acrylamide are added to the solution obtained in step S2, heated and stirred until completely dissolved; S4, nicotinamide prodrug is added to the solution obtained in step S3, and stirred and dissolved; wherein the structure of the nicotinamide prodrug is ; S5, N,N'-methylene bisacrylamide and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] are dissolved in water and fully dissolved; S6, the solution obtained in step S5 is added to the solution in step S4 in a set proportion, and mixed uniformly; S7, the mixed solution prepared in step S6 is filled with nitrogen to exclude oxygen, and then a thermal initiation polymerization reaction is carried out to form a double-crosslinked hydrogel; In the solution obtained in S1, the mass concentration of 2-acrylamido-2-methylpropanesulfonic acid is 3-8%; In the solution obtained in S3, the mass concentration of polyvinyl alcohol is 5-15%, and the mass concentration of acrylamide is 5-15%; In the solution obtained in S4, the mass concentration of nicotinamide prodrug is 0%-25%, excluding 0%; In the solution obtained in S6, the mass concentration of N,N'-methylene bisacrylamide is 0.03-0.08%, and the mass concentration of 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] is 0.05-0.15%.

3. The method for preparing a ROS-responsive, controllable drug release and high-stretch, high- viscosity hydrogel according to claim 2, wherein the step of polymerizing the monomer solution is performed by adding a photoinitiator to the monomer solution and irradiating the monomer solution with light. In S2, the pH is 7.5-8.

5.

4. The method for preparing a ROS-responsive, controllable drug release and high-stretch, high- viscosity hydrogel according to claim 2, wherein the step of polymerizing the monomer solution is performed at a temperature of 4 to 40°C for 1 to 10 hours. In S7, the polymerization reaction time is 10-15 h; the reaction temperature is 85-95℃.

5. The use of the ROS-responsive drug-controlled and high-stretching and high-viscosity hydrogel of claim 1 or the hydrogel prepared by the method of any one of claims 2-4 in the preparation of a drug or dressing for repairing incised wounds and scratches.

6. The use of the ROS-responsive drug-controlled and high-stretching and high-viscosity hydrogel of claim 1 or the hydrogel prepared by the method of any one of claims 2-4 in the preparation of drugs for various wounds.

7. Use according to claim 6, characterized in that, The wound is a linear wound repair and / or a facial wound repair.

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