Preparation method and application of super lubricating hydrogel

Abstract

The present invention discloses a method for preparing a super-lubricating hydrogel and its application, relating to the field of medical technology. The present invention utilizes a surface-initiated atom transfer radical polymerization reaction to graft a 2-methacryloyloxyethyl phosphorylcholine polymer onto the surface of a methacrylated gelatin hydrogel matrix to obtain a super-lubricating hydrogel. The super-lubricating hydrogel prepared by the present invention can be used as a super-lubricating interface for enhancing tribological properties of biomimetic articular cartilage, constructing a novel low-friction, wear-resistant biomimetic articular cartilage scaffold, thereby resolving the shortcomings of current cartilage repair materials. This is of great significance for promoting the development of articular cartilage repair technology and improving the quality of life of patients with articular cartilage injuries.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to a preparation method of a super-lubricating hydrogel and application thereof. Background Art

[0002] Cartilage diseases are both a hot topic and a challenging area of ​​medical research. For example, osteoarthritis, the most common disease, has surpassed cardiovascular disease to become the world's leading cause of disability. Articular cartilage defects are a significant cause of disability in the general population and the leading cause of combat readiness training suspensions for military personnel, making them a pressing issue in both general and military medicine. Due to the intense, long-term combat readiness training, military personnel are frequently subjected to abnormal forces on their knees and temporomandibular joints (TMJs), resulting in a much higher incidence of arthritis than the general population.

[0003] Articular cartilage is a highly organized elastic connective tissue covering the surface of human joints, performing important functions in human joints, including load bearing, cushioning, and lubrication. Although articular cartilage provides an excellent lubricated interface, it continues to wear and tear due to excessive loads and repetitive movement, ultimately leading to joint aging, injury, and common diseases such as osteoarthritis. Clinically, articular cartilage defects are caused by a variety of factors, including osteoarthritis, sports injuries, training impacts, and temporomandibular joint disorders. Adverse stress can cause mild damage to the articular cartilage, resulting in a rough joint surface that can further develop into articular cartilage defects.

[0004] Because articular cartilage lacks blood vessels, lymphatic vessels, or neural tubes, its ability to heal and regenerate is inherently limited. Currently, clinical treatments for cartilage defects rely primarily on surgical therapies, such as medication and arthroscopic debridement, microfracture, autologous cartilage transplantation, allogeneic cartilage transplantation, and autologous chondrocyte transplantation. However, these procedures primarily focus on short-term pain relief and have limitations in promoting cartilage regeneration, failing to meet current clinical treatment needs.

[0005] With the rapid development of regenerative medicine, the emergence of stem cell-based cartilage tissue engineering (CTE) has broadened the horizons of traditional cartilage defect treatment technology and has gradually become a hot topic in cartilage defect repair research. This technology is to restore, maintain and improve the function of articular cartilage by loading stem cells and growth factors on a degradable scaffold material. The three elements of tissue engineering research include: scaffold, cells and growth factors, and its purpose is to achieve functional regeneration, maintenance and improvement of damaged tissue. Cartilage tissue engineering usually includes three steps: (1) in vitro expansion of therapeutic cells; (2) culturing stem cells and growth factors in a scaffold to form a cell scaffold; (3) implanting the cell scaffold into the tissue defect, and as new cartilage is formed in situ, the scaffold gradually degrades. Due to the difficulty of articular cartilage regeneration and its complex structure and function in a load environment, there are still many problems to be solved in cartilage tissue engineering, such as improving the mechanical properties of the scaffold material, constructing a tissue surface lubrication system, and achieving tissue structure integration.

[0006] The microenvironment of articular cartilage is complex, so scaffold materials that combine mechanical properties, surface lubrication, and tissue structural integration are key factors in cartilage tissue engineering. They are primarily made of natural and artificial polymers and composite materials, often appearing in the form of sponges, lattices, membranes, nanofibers, and hydrogels. Hydrogels are networks of hydrophilic polymer chains, also known as colloidal gels. Due to their inherent cross-linked structural integrity and similarity to natural cartilage structure, hydrogels are considered ideal biomaterials for articular cartilage repair due to their hydrophilicity and solid-like properties. Methacrylamide gelatin (Gel-MA) hydrogels are widely used in tissue engineering due to their excellent biocompatibility and controllability. After cross-linking, this hydrogel forms a stable three-dimensional network structure with strong support, good thermosensitive gel properties, and biodegradability, which can simulate the mechanical cushioning and support functions of articular cartilage.

[0007] Therefore, constructing a new type of low-friction and wear-resistant bionic articular cartilage scaffold to address the shortcomings of current cartilage repair materials is of great significance to promoting the development of articular cartilage repair technology and improving the quality of life of patients with articular cartilage injuries. Summary of the Invention

[0008] The purpose of the present invention is to provide a preparation method of a super-lubricating hydrogel and its application, thereby solving the problem that cartilage repair hydrogel scaffolds cannot be properly repaired due to insufficient surface lubricity of the cartilage repair hydrogel scaffolds.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] The present invention provides a method for preparing a super lubricating hydrogel, comprising the following steps:

[0011] The super-lubricating hydrogel is obtained by grafting 2-methacryloyloxyethyl phosphorylcholine polymer on the surface of the methacrylated gelatin hydrogel matrix through surface-initiated atom transfer radical polymerization reaction.

[0012] The specific reaction process is as follows:

[0013]

[0014] As a further preference of the present invention, the reaction temperature of the surface-initiated atom transfer radical polymerization reaction is room temperature, and the reaction time is 2-3 hours.

[0015] As a further preference of the present invention, the method specifically comprises the following steps:

[0016] soaking the methacryloylated gelatin hydrogel matrix in an initiator solution to obtain a methacryloylated gelatin hydrogel matrix with the initiator attached to the surface;

[0017] The methacryloylated gelatin hydrogel matrix with an initiator connected to the surface is immersed in a 2-methacryloyloxyethyl phosphorylcholine monomer solution, and the super-lubricating hydrogel is obtained by surface-initiated atom transfer radical polymerization reaction.

[0018] Further preferred steps are as follows:

[0019] (1) Using 5-20 mL of PBS buffer solution as a solvent, 5-20 wt% methacryloyl gelatin (GelMA) as a solute, and adding 5-10 mg of Irgacure 2959 as a photoinitiator, the resulting solution was heated in a water bath at 50°C and stirred for 2-3 h. The resulting solution was then cast into a cylindrical mold and placed under ultraviolet light for 10-20 min to crosslink. The mold was then removed and washed with PBS to obtain a columnar GelMA hydrogel, which was stored in PBS solution at 4°C.

[0020] (2) Immerse the smoother end of the columnar GelMA hydrogel in a 5-10 mg / mL SI-ATRP initiator solution in the dark for 18-30 h, and wash with PBS to obtain a GelMA hydrogel with an initiator at one end;

[0021] (3) 1 g of MPC monomer, 1 mL of deionized water, and 0.5 mL of methanol were mixed, and 18.4 μL of pentamethyldiethylenetriamine (PMDETA) was added to prepare an MPC monomer solution. The MPC monomer solution was dropped on a copper foil, and then the end of the columnar GelMA hydrogel connected with the initiator was placed on the copper foil dripped with the MPC monomer solution for SI-ATRP reaction. The reaction was carried out for 2-3 h, and then the superlubricating hydrogel was washed three times with PBS and disinfected with medical alcohol to obtain a superlubricating hydrogel, which was then stored in a PBS solution at 4 °C.

[0022] The present invention also provides a super-lubricating hydrogel prepared by the above preparation method.

[0023] The present invention further provides the use of the super-lubricating hydrogel as a cartilage repair hydrogel scaffold material.

[0024] Articular cartilage possesses exceptional lubrication properties due to the presence of charged biomacromolecules on its surface, which form a "hydration lubrication" mechanism. Hydration lubrication converts friction between two surfaces into friction between water molecules on the surface through ion-dipole interactions. In healthy articular cartilage, biomacromolecules such as hyaluronic acid, proteoglycans, lubricin, and phospholipids form bottlebrush-like polymer molecular brushes. These charged biomacromolecules readily form a hydration layer, which is crucial for maintaining excellent lubrication and cushioning properties in joints.

[0025] Using GelMA to construct a high-performance cartilage repair scaffold, and further constructing a dual-function scaffold that simultaneously guides the regeneration of cartilage and subchondral bone, and reconstructing full-thickness osteochondral defects, has important social significance and academic value. Phosphorylcholine polymers MPC have special properties such as good blood and tissue compatibility and hydrophilicity. The present invention grafts a layer of PMPC polymer brush with a high degree of hydration on the surface of GelMA hydrogel through surface-initiated atom transfer radical polymerization (SI-ATRP), thereby increasing the lubricity of the hydrogel surface without sacrificing the mechanical strength of the GelMA hydrogel, thereby achieving superlubricity.

[0026] The grafted MPC polymer brushes of the present invention contain zwitterionic groups. The hydration and lubrication effects of the zwitterionic phosphorylcholine groups significantly reduce friction. Furthermore, since protein adsorption can cause biofouling, leading to biofilm formation, thrombosis, and foreign body reactions, proteins are more readily adsorbed on hydrophobic surfaces, while protein adsorption on hydrophilic surfaces is generally relatively weak. Zwitterionic polymer brushes attract water molecules and repel protein molecules. The zwitterionic moieties in the material strongly attract water molecules, creating a hydration layer that resists dehydration and maintains high pressure, thereby forming stable interfacial lubrication.

[0027] The present invention creatively combines a methacryloyl (GelMA) hydrogel matrix with an MPC polymer molecular brush. Based on the structure of mature articular cartilage, a chemical grafting method is used to mimic the biomimetic cartilage structure to construct a hydrogel scaffold (GelMA-MPC) with a super-lubricating molecular brush coating. This solves the problems of poor surface lubricity, weak mechanical support performance, and poor biocompatibility of existing scaffold materials, ultimately achieving the goal of cartilage repair.

[0028] The present invention discloses the following technical effects:

[0029] The present invention grafts poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC) on the surface of methacryloyl (GelMA) to simulate the super-lubricating interface of bionic articular cartilage to enhance the tribological properties, thereby constructing a new low-friction, wear-resistant bionic articular cartilage scaffold, thereby addressing the shortcomings of current cartilage repair materials. This is of great significance for promoting the development of articular cartilage repair technology and improving the quality of life of patients with articular cartilage injuries. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 Schematic diagram of the preparation reaction of the super-lubricating hydrogel in Example 1 of the present invention.

[0032] Figure 2 Schematic diagram of the preparation process of super-lubricating hydrogel in Example 1 of the present invention.

[0033] Figure 3 This is a graph showing the lubricity coefficient test results of the superlubricating hydrogel in Example 1 of the present invention.

[0034] Figure 4 Surface and cross-sectional microstructures of GelMA hydrogel and GelMA-MPC hydrogel in Example 1 of the present invention.

[0035] Figure 5 The in vitro degradation diagram (a) and cytotoxicity diagram (b) of the hydrogel prepared in Example 1 of the present invention are shown.

[0036] Figure 6 This is a tissue section diagram of the systemic toxicity test of the hydrogel prepared in Example 1 of the present invention.

[0037] Figure 7 This is the culture situation of primary chondrocytes on molecular brush layer.

[0038] Figure 8 Bone marrow mesenchymal stem cells cultured on a hydrogel scaffold.

[0039] Figure 9 As an example to verify the effect of the present invention, the rabbit knee cartilage defects were repaired in vivo in different treatment groups. Gross observation results and scores were obtained 3 months later.

[0040] Figure 10 This is an example of the effectiveness verification of the present invention, showing the Micro CT images and BV / TV measurement values ​​of the subchondral bone repair effect of different treatment groups after repairing rabbit knee cartilage defects for 3 months.

[0041] Figure 11 This is an example of validation of the effect of the present invention. The histological (HE staining and Safranin O fast green staining) observation results were obtained 3 months after the rabbit knee cartilage defects were repaired in vivo in different treatment groups. DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0043] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0044] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0045] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0046] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0047] Example 1

[0048] (1) 10 mL of PBS buffer solution was used as the solvent, and then the solute component GelMA was added to make the mass percentage of the solute 5 wt%. Then, 50 mg of photoinitiator Irgacure 2959 was added, and the resulting solution system was heated in a 50°C water bath and stirred for 2 h. The resulting solution was cast into a cylindrical mold with a diameter of 6 mm and a thickness of 2 mm and placed under ultraviolet light for 1 h to crosslink it. The mold was then removed and washed with PBS to obtain a columnar GelMA hydrogel, which was stored in PBS solution at 4°C.

[0049] (2) The smoother end of the columnar GelMA hydrogel was immersed in a 10 mg / mL SI-ATRP initiator solution in the dark for 24 h. After washing with PBS, a GelMA hydrogel with an initiator at one end was obtained.

[0050] (3) 1 g of MPC monomer, 1 mL of deionized water, and 0.5 mL of methanol were mixed, and 18.4 μL of pentamethyldiethylenetriamine (PMDETA) was added to prepare an MPC monomer solution. The MPC monomer solution was dropped on a copper foil, and then the end of the columnar GelMA hydrogel connected with the initiator was placed on the copper foil dripped with the MPC monomer solution for SI-ATRP reaction. The reaction was carried out for 2 h, and then the columnar GelMA hydrogel was washed three times with PBS and disinfected with medical alcohol to obtain a superlubricating hydrogel GelMA-MPC, which was then stored in a PBS solution at 4 °C.

[0051] Figure 1 Schematic diagram of the preparation reaction of the super-lubricating hydrogel in Example 1 of the present invention.

[0052] Figure 2 Schematic diagram of the preparation process of super-lubricating hydrogel in Example 1 of the present invention.

[0053] Friction coefficient determination: The experiment was conducted using a friction and wear testing machine. A hard steel ball was used as an indenter to contact the hydrogel sample, and pure water was used as a lubricant. The two were then subjected to relative motion to measure the friction coefficient.

[0054] Figure 3 This is a graph showing the lubricity coefficient test results of the superlubricating hydrogel in Example 1 of the present invention.

[0055] Scanning electron microscopy observation of the surface microstructure of GelMA hydrogel and GelMA-MPC hydrogel:

[0056] GelMA hydrogel and GelMA-MPC hydrogel were placed in a freeze dryer. The condenser was first cooled and maintained at -40°C. The chamber cooling valve was then opened to maintain a vacuum at -40°C. After 24 hours, the instrument was shut down, the sample removed, and placed on a conductive plate. An automated sputtering device was then used for 180 seconds at 20 mA to platinum-coate the particle surface to enhance conductivity. The surface structures of the two hydrogels were observed using a scanning electron microscope.

[0057] Using the same method, GelMA and GelMA-MPC hydrogels were vacuumed at -40°C for 24 hours. After removal, the samples were fractured at the center, with the cross-section facing upward, and placed on a conductive plate. Subsequently, an automated sputtering apparatus was used at 20 mA for 180 seconds to platinum-coate the particle surface to enhance conductivity. The cross-sectional structures of the two hydrogels were observed using a scanning electron microscope.

[0058] Figure 4 The surface and cross-sectional microstructures of GelMA hydrogel and GelMA-MPC hydrogel in Example 1.

[0059] Effect verification example:

[0060] The performance of the GelMA hydrogel and GelMA-MPC hydrogel prepared in Example 1 was tested:

[0061] 1. In vitro degradation test:

[0062] Degradation experiments were performed on GelMA and GelMA-MPC scaffolds immersed in simulated body fluid (SBF) at a 1:10 ratio of scaffold weight (g) to simulated body fluid volume (ml). The scaffolds were placed in a constant temperature shaker (37°C, 100 rpm). The SBF was refreshed every two days. The scaffolds were vacuum-dried and weighed every five days. The residual mass percentage was calculated at each time point, and degradation curves were plotted.

[0063] 2. Biocompatibility testing:

[0064] (1) Cytotoxicity test: The biocompatibility of the hydrogel material was evaluated by using bone marrow mesenchymal stem cell proliferation experiment and adhesion observation on the scaffold.

[0065] The two scaffolds (GelMA hydrogel and GelMA-MPC hydrogel) were cut into thin slices with a diameter of 6 mm and a thickness of 1 mm and placed in a 96-well plate. A control group (culture medium containing cells) was also added. Each group was set up with three replicates and an observation period of 7 days. Bone marrow mesenchymal stem cell suspension was prepared and counted. The cell suspension was inoculated in a 96-well plate, with approximately 100 μl of cell suspension per well, 5,000 cells, and three replicates per group. The culture plate was placed in an incubator for a period of pre-incubation (37°C, 5% CO2). It takes about 2 hours for the cells to attach to the wall. On the first day (after 24 hours), the culture medium was replaced, and 10 μl of CCK-8 solution was added to each well. The culture plate was placed in an incubator and incubated for 1 hour. The absorbance (OD) at 450 nm was measured with a microplate reader. The absorbance value was measured daily using the above method for seven consecutive days.

[0066] Figure 5 Figure 1 shows the in vitro degradation diagram (a) and cytotoxicity test diagram (b) of the hydrogel prepared in Example 1 of the present invention.

[0067] (2) Systemic toxicity test:

[0068] First, the hydrogel material extract was prepared. According to the calculation formula for the extract volume in GB / T 16886.12-2023, GelMA hydrogel and GelMA-MPC hydrogel were prepared into uniform cylinders with a diameter of 6 mm and a thickness of 2 mm. Then, 3.6 ml of PBS was calculated for each hydrogel. The two hydrogels were then added to PBS and the resulting extract mixture was placed in a constant temperature incubator at 37±1°C. After 24±2 hours, the material was removed to obtain the extract corresponding to each group. Fifteen healthy SD rats (male, 8 weeks old, 250±50g) were divided into a blank control group, a GelMA group, and a GelMA-MPC group, with 5 rats in each group. Under the same conditions, they were allowed to eat freely and had a 12-hour day and night rhythm. The experiment was carried out one week later. According to GB / T16886.11-2021, each rat in each group was intraperitoneally injected with 5 ml of the corresponding hydrogel extract, and the blank control group was injected with the same dose of PBS. Two weeks later, the heart, liver, spleen, lung, and kidney of the SD rats were fixed and embedded in wax blocks, then sectioned, stained with HE, and observed under an upright microscope.

[0069] Figure 6 This is a tissue section diagram of the systemic toxicity test of the hydrogel prepared in Example 1 of the present invention.

[0070] 3. In vitro experiments:

[0071] Observation of cell adhesion to molecular brushes: MPC molecular brushes were coated on cell slides (control group without MPC molecular brushes) and primary chondrocytes were seeded on them. After 24 hours of culture, cells were fixed with 2.5% glutaraldehyde at 4°C for 15 minutes and then incubated with FITC-phalloidin (5 μg / mL) at 37°C for 45 minutes. Observation was performed using a laser confocal microscope.

[0072] Figure 7 The figure shows the culture of primary chondrocytes on the molecular brush layer. Compared with the control group, the molecular brush layer has slightly fewer cell brushes, which is related to the low lubricity of the molecular brush layer, which is not conducive to cell attachment.

[0073] Observation of cell migration and adhesion in the super-lubricating hydrogel matrix layer: In order to avoid mechanical changes to the polymer caused by high-temperature sterilization, the super-lubricating hydrogel scaffold GelMA-MPC was soaked in 75% ethanol for 2 hours, then freeze-dried, pre-soaked in culture medium for 24 hours, and then bone marrow mesenchymal stem cell suspension was inoculated on each sample. After culturing for 12 hours, 24 hours and 48 hours, it was fixed with 2.5% glutaraldehyde at 4°C for 15 minutes, and then incubated with FITC-phalloidin (5ug / mL) at 37°C for 45 minutes. A 3D confocal laser scanning microscope was used to scan the cells from bottom to top (scanning volume 632.84×632.84×52um 3 ) reconstructed a three-dimensional image of the cell distribution within the scaffold.

[0074] Figure 8 Figure 2 shows the culture of bone marrow mesenchymal stem cells on the hydrogel scaffold GelMA-MPC. The figure shows that bone marrow mesenchymal stem cells can adhere and migrate well in the hydrogel scaffold GelMA-MPC.

[0075] 4. In vivo experiments

[0076] Fifteen 3-month-old female New Zealand white rabbits were selected and randomly divided into a blank control group, a GelMA group, and a GelMA-MPC group, with 5 rabbits in each group. 2% sodium pentobarbital was used for intravenous anesthesia. The knee joint was exposed through a lateral parapatellar incision, and the medial patella was dislocated to expose the anterior articular surface of the distal femur. A cartilage defect (6 mm in diameter, 2 mm deep) was created on the articular surface of the femoral patellar groove using an electric ring drill. After flushing the joint with sterile saline, GelMA and GelMA-MPC (6 mm in diameter, 2 mm deep) were implanted into the cartilage defect. The blank control group was not filled with any substance, and the knee joint capsule and skin were sutured layer by layer. Each experimental rabbit was raised individually in a cage, fed a normal diet, and could move its legs freely. After 12 weeks, the experimental rabbits were killed by injection of an overdose of anesthetics, and samples were taken from the knee joints. The gross specimens were observed and scored.

[0077] Figure 9As an example to verify the effect of the present invention, the rabbit knee cartilage defects were repaired in vivo in different treatment groups. Gross observation results and scores were obtained 3 months later.

[0078] Micro-CT images of the recovered cartilage regeneration tissue were taken, and the images were reconstructed using a high-resolution micro-CT imaging system. A cylindrical area with a diameter of 6 mm and a depth of 4 mm centered on the defect was selected as the region of interest (ROI). The bone volume / tissue volume (BV / TV) ratio was quantified to compare the ossification area between the different groups.

[0079] Figure 10 This is an example of the effectiveness verification of the present invention, showing the Micro CT images and BV / TV measurement values ​​of the subchondral bone repair effect of different treatment groups after repairing rabbit knee cartilage defects for 3 months.

[0080] Histological staining. Samples were fixed in 4% paraformaldehyde, decalcified in 10% EDTA, dehydrated in a graded alcohol series, and embedded in paraffin. 4-μm-thick thin sections were sliced, dehydrated, and stained with Safranin O Fast Green to visualize the cartilage matrix. Hematoxylin / eosin (HE) staining was used as a reference.

[0081] Figure 11 This is an example of validation of the effect of the present invention. The histological (HE staining and Safranin O fast green staining) observation results were obtained 3 months after the rabbit knee cartilage defects were repaired in vivo in different treatment groups.

[0082] Compared with the physical grafting method, the polymer brush obtained by the chemical grafting method adopted in the present invention will not fall off under the force when the product is sheared, and can produce effective lubrication.

[0083] The present invention is based on the load-bearing performance of the bionic cartilage glue network of the hydrogel scaffold, and a super-lubricating molecular brush layer is coated on the surface of the material to construct a new tissue engineering material, providing a new method for repairing cartilage defects.

[0084] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a super lubricating hydrogel, characterized in that: The following steps are involved: (1) Use 5-20 mL PBS buffer solution as solvent, 5-20 wt% methacrylated gelatin as solute, add 5-10 mg Irgacure 2959 as photoinitiator, heat the resulting solution in a water bath at 50 °C and stir for 2-3 h, then cast the resulting solution into a cylindrical mold and place it under ultraviolet light for 10-20 min to crosslink it, then remove the mold and wash with PBS to obtain a columnar GelMA hydrogel, which was stored in PBS solution at 4 °C; (2) Immersing the smoother end of the columnar GelMA hydrogel in a 5-10 mg / mL SI-ATRP initiator solution for 18-30 h in the dark, and washing with PBS to obtain a GelMA hydrogel with an initiator at one end; (3) 1 g of MPC monomer, 1 mL of deionized water, and 0.5 mL of methanol were mixed, and 18.4 μL of pentamethyldiethylenetriamine was added to prepare an MPC monomer solution. The MPC monomer solution was dropped on a copper foil, and then the end of the columnar GelMA hydrogel connected with the initiator was placed on the copper foil dripped with the MPC monomer solution for SI-ATRP reaction. The reaction was carried out for 2-3 h, and then the superlubricating hydrogel was washed three times with PBS and disinfected with medical alcohol to obtain the superlubricating hydrogel, which was then stored in a PBS solution at 4 °C.

2. The preparation method according to claim 1, characterized in that The surface initiated atom transfer radical polymerization reaction is carried out at room temperature for 2-3 hours.

3. The super-lubricating hydrogel prepared by the preparation method as claimed in claim 1.

4. Use of the super lubricating hydrogel as claimed in claim 3 as a cartilage repair hydrogel scaffold material.

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