High-strength toughened composite hydrogel for articular disc replacement / repair, preparation method and application thereof

Abstract

The application discloses a high-strength and high-toughness composite hydrogel for articular disc replacement / repair, a preparation method and application thereof, and belongs to the technical field of biomaterials. The preparation method of the composite hydrogel comprises the following steps: taking cyclodextrin grafted polyurethane and polyvinyl alcohol as raw materials, and freezing-thawing circulation after blending to prepare the composite hydrogel. The composite hydrogel prepared by the above preparation method is disclosed. The application also discloses application of the composite hydrogel in preparation of materials for repairing or / and replacing the temporomandibular joint disc. The composite hydrogel is prepared by using the cyclodextrin grafted polyurethane water emulsion and polyvinyl alcohol for the first time, the preparation method is simple and easy to operate, the obtained composite hydrogel has the characteristics of high strength and high toughness, and can be used for preparing the materials for repairing / replacing the temporomandibular joint disc.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological materials, and particularly relates to a high-strength and high-toughness composite hydrogel for temporomandibular disc replacement / repair, a preparation method thereof and application. BACKGROUND

[0002] As the only movable joint of the human oral and maxillofacial region, the temporomandibular joint mainly realizes basic physiological functions such as mastication, speech, and expression through the reciprocating movement of the articular disc with the mandibular head. Clinically, temporomandibular joint disc damage caused by factors such as osteoarthritis, trauma, and tumors is very common, and the temporomandibular joint disease caused thereby accounts for about 18%-58% of oral-related diseases.

[0003] At present, the clinical treatment methods for temporomandibular joint disc damage are divided into conservative treatment and surgical treatment. For cases with relatively mild symptoms, non-invasive or minimally invasive conservative treatment (such as occlusal splinting, intra-articular injection, etc.) is mainly adopted. For severe cases, temporomandibular disc resection and temporomandibular disc reconstruction are mostly selected in clinical practice. Although temporomandibular disc resection can relieve pain, it, like conservative treatment, cannot effectively prevent the expansion of the damaged disc and the occurrence of degenerative changes of the joint tissue. Temporomandibular disc reconstruction is expected to prevent the occurrence of degenerative changes and restore the normal function of the temporomandibular joint. Since the cell density of the temporomandibular disc is low and lacks blood supply, its self-repairing ability is poor, and once damaged, it is difficult to heal, so it is necessary to use a temporomandibular disc replacement implant to reconstruct the temporomandibular disc. Among them, autologous temporomandibular fascial flap and allogeneic acellular dermal matrix, collagen membrane, and dura mater are commonly used in clinical practice. However, the above-mentioned replacement implants are far from the natural temporomandibular disc in terms of tissue composition, structure, morphology, and biomechanical properties, making it impossible to bear the physiological load of the temporomandibular joint movement for a long time. Therefore, seeking a new type of temporomandibular disc replacement material with suitable performance has become a great hope to break through the bottleneck of clinical temporomandibular disc repair.

[0004] The natural temporomandibular disc tissue has high mechanical strength and toughness. When subjected to external impact or extrusion, the temporomandibular disc tissue will undergo moderate deformation, effectively disperse the pressure through energy dissipation, avoid stress concentration, and thus buffer and protect the joint from damage. The natural temporomandibular disc is composed of collagen and proteoglycans. Among them, collagen serves as a rigid support and stability structure; proteoglycans have hydrophilic properties, retain water, and at the same time impart good elasticity to the tissue, enhancing the toughness of the tissue.

[0005] Hydrogel is considered an optimal soft tissue replacement material due to its structural characteristics and physicochemical properties, which are very similar to the extracellular matrix of the human body. At present, hydrogel materials have made series of progress in the replacement and repair of soft cartilage tissues such as articular cartilage, intervertebral disc, meniscus, and temporomandibular disc.

[0006] At present, the synthetic hydrogel material can improve the mechanical strength of the material by changing the components and adjusting the preparation process, but it is difficult to consider high toughness, because of the contradiction between the bonding strength and arrangement, mobility of the atoms or molecules inside. High bonding strength brings high strength, but limits the deformation and reduces the toughness; while high mobility and rearrangement give high toughness, but often weaken the bonding strength and reduce the strength. Based on this, how to construct a hydrogel material with high strength and high toughness for the repair / replacement of the temporomandibular joint disc has become a key problem to be solved at present. SUMMARY

[0007] One of the purposes of the present application is to provide a preparation method of a high-strength and high-toughness composite hydrogel for the repair / replacement of the temporomandibular joint disc, and the composite hydrogel prepared by the method has high strength and high toughness, and can be used to prepare a material for repairing / replacing the temporomandibular joint disc.

[0008] The second purpose of the present application is to use the composite hydrogel prepared by the above method.

[0009] The third purpose of the present application is to provide the application of the composite hydrogel.

[0010] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0011] The present application discloses a preparation method of a high-strength and high-toughness composite hydrogel for the repair / replacement of the temporomandibular joint disc, which comprises the following steps: using cyclodextrin grafted polyurethane and polyvinyl alcohol as raw materials, and blending and then freezing-thawing to prepare the composite hydrogel.

[0012] In some embodiments of the present application, the preparation method comprises the following steps:

[0013] S1. preparing a cyclodextrin grafted polyurethane water emulsion;

[0014] S2. preparing a polyvinyl alcohol aqueous solution: adding polyvinyl alcohol into water and stirring under heating to prepare the polyvinyl alcohol aqueous solution;

[0015] S3. mixing the cyclodextrin grafted polyurethane water emulsion and the polyvinyl alcohol aqueous solution, stirring uniformly, freezing-thawing to prepare the composite hydrogel.

[0016] In some embodiments of the present application, the step S1 comprises the following steps:

[0017] S11. mixing isophorone diisocyanate and polytetrahydrofuran ether diol, heating and stirring under inert gas, adding a catalyst and continuing to heat and stir;

[0018] S12. β-cyclodextrin graft modification: β-cyclodextrin is added to the solution prepared in step S11, and heated and stirred to perform graft modification;

[0019] S13. Chain extension: a chain extender is added to the solution prepared in step S12 to perform chain extension, and heated and stirred to obtain a prepolymer solution;

[0020] S14. Neutralization and emulsification: a neutralizing agent is added to the prepolymer solution prepared in step S13 to perform emulsification, and stirred to form a water emulsion of cyclodextrin grafted polyurethane;

[0021] Preferably, the chain extender comprises 2,2-dimethylol propionic acid;

[0022] Preferably, the molar ratio of each substance is as follows:

[0023] Isophorone diisocyanate: (polytetrahydrofuran ether glycol + β-cyclodextrin + chain extender) = 4:1-1:1; preferably 2:1;

[0024] Polytetrahydrofuran ether glycol: (β-cyclodextrin + chain extender) = 1:1-1:3, preferably 1:1.5;

[0025] β-cyclodextrin: (isophorone diisocyanate + polytetrahydrofuran ether glycol + β-cyclodextrin + chain extender) = 1:100-4:100, preferably 2:100.

[0026] In some embodiments of the present application, in step S11, the isophorone diisocyanate and polytetrahydrofuran ether glycol are mixed and heated and stirred at 75-95°C, more preferably at 85°C; the stirring time is 10-30 min, more preferably 20 min;

[0027] Preferably, the catalyst is stannous octoate; preferably, after adding the catalyst, the heating and stirring is continued at 75-95°C, more preferably at 85°C; the stirring time is 1.5-3 h, preferably 2 h.

[0028] In some embodiments of the present application, in step S12, β-cyclodextrin solution is added to the solution prepared in step S11 to perform graft modification;

[0029] Preferably, the β-cyclodextrin solution is a N,N-dimethylformamide solution of β-cyclodextrin, and the concentration thereof is preferably 25-55 w / v%, more preferably 27 w / v%.

[0030] Preferably, after adding the β-cyclodextrin solution, the heating and stirring is performed at 60-80°C, more preferably at 70°C; the stirring time is 30-120 min, more preferably 60 min.

[0031] In some embodiments of the present application, in step S13, the solution prepared in step S12 is heated and stirred at 55-75°C, more preferably 65°C, after adding the chain extender solution; the stirring time is 1-3h, more preferably 2h.

[0032] Preferably, the chain extender solution is an N,N-dimethylformamide solution of 2,2-dimethylol propionic acid.

[0033] In some embodiments of the present application, in step S14, the neutralizing agent is an aqueous solution of triethylamine.

[0034] Preferably, the molar ratio of triethylamine to 2,2-dimethylol propionic acid is 1:1.

[0035] Preferably, the water content in the cyclodextrin-grafted polyurethane water emulsion is 50wt.%-85wt.%, preferably 70wt.%.

[0036] In some embodiments of the present application, in step S2, the polyvinyl alcohol aqueous solution is prepared by adding water to polyvinyl alcohol and stirring at 90-98°C for 2-12h to obtain a polyvinyl alcohol aqueous solution with a mass fraction of 15-50%, preferably 25-35%, more preferably 30%.

[0037] In step S3, the mass ratio of the solid content in the cyclodextrin-grafted polyurethane water emulsion to the polyvinyl alcohol is 1:1-1:3, preferably 1:3.

[0038] The solid content in the cyclodextrin-grafted polyurethane water emulsion refers to the total mass of isophorone diisocyanate, polytetrahydrofuran ether diol, β-cyclodextrin, 2,2-dimethylol propionic acid, and triethylamine.

[0039] Preferably, the solid content in the solution obtained after mixing the cyclodextrin-grafted polyurethane water emulsion with the polyvinyl alcohol aqueous solution is 20-50%, preferably 30%.

[0040] Preferably, the number of freeze-thaw cycles is 9-15, more preferably 10.

[0041] Preferably, the freezing temperature is -30°C to -10°C, more preferably -20°C.

[0042] Preferably, the freezing time is 6-24h, more preferably 12h.

[0043] Preferably, the thawing temperature is room temperature, more preferably 25°C.

[0044] The composite hydrogel prepared by the above preparation method is disclosed in the present application.

[0045] The application discloses application of the composite hydrogel in preparation of a material for repairing or / and replacing a temporomandibular joint disc.

[0046] The w / v% in the application represents mass volume ratio, for example, the concentration of a N,N-dimethylformamide solution of beta-cyclodextrin is 27 w / v%, which means that 27g of beta-cyclodextrin is added to 100ml of N,N-dimethylformamide.

[0047] The English abbreviations in the application correspond to the following Chinese names:

[0048] IPDI: isophorone diisocyanate;

[0049] PTMEG: polytetramethylene ether glycol;

[0050] CD: beta-cyclodextrin;

[0051] DMF: N,N-dimethylformamide;

[0052] DMPA: 2,2-dimethylol propionic acid;

[0053] PVA: polyvinyl alcohol;

[0054] CD-PU: cyclodextrin grafted polyurethane.

[0055] Compared with the prior art, the application has the following beneficial effects:

[0056] The application has the advantages of scientific design and ingenious concept, the composite hydrogel is prepared by using a cyclodextrin grafted polyurethane water emulsion and polyvinyl alcohol for the first time, the preparation method is simple and easy to operate, the obtained composite hydrogel has high strength and high toughness, and can be used for preparing a material for repairing / replacing a temporomandibular joint disc. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 It is a mechanical compression curve graph of test example 1 of the application; wherein the vertical coordinate Compression stress represents compression stress, and the horizontal coordinate Strain represents strain.

[0058] Figure 2 It is a mechanical compression modulus calculation result graph of test example 1 of the application; wherein the vertical coordinate Compression modulus represents compression modulus.

[0059] Figure 3 It is a mechanical tensile curve graph of test example 1 of the application; wherein the vertical coordinate Tensile stress represents tensile stress, and the horizontal coordinate Strain represents strain.

[0060] Figure 4The figure is the calculation result of the mechanical tensile breaking energy and breaking elongation of the test example 1 of the present application; wherein Tearenergy represents the breaking energy, and Elongation at break represents the breaking elongation.

[0061] Figure 5 The figure is the tensile cycle test result of the test example 1 of the present application; the vertical coordinate Tensile stress represents the tensile stress, and the horizontal coordinate Strain represents the strain.

[0062] Figure 6 The figure is the tensile cycle energy dissipation calculation result of the test example 1 of the present application; Hysteresis Energy represents the hysteresis curve energy consumption.

[0063] Figure 7 The figure is the friction and wear test curve of the test example 1 of the present application, wherein the vertical coordinate Friction coefficient represents the friction coefficient, and the horizontal coordinate Cycles represents the friction and wear cycle number.

[0064] Figure 8 The figure is the cell proliferation result of the articular disc cells co-cultured with the material for 1 day, 3 days and 5 days in the test example 2;

[0065] Figure 9 The figure is the hemolysis rate result of the test example 2. DETAILED DESCRIPTION

[0066] In order to make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of the present application. Unless otherwise specifically stated, all the various raw materials, reagents, instruments and equipment and the like used in the present application can be purchased from the market or can be prepared by the existing method.

[0067] The polytetrahydrofuran ether diol used in the embodiments of the present application has a molecular weight of 2000.

[0068] The calculation formula of the solid content in the embodiments of the present application is as follows:

[0069]

[0070] W IPDI , W PTMEG , W CD , W DMPA , W 三乙胺 , W 水Mass of IPDI, PTMEG, CD, DMPA, triethylamine, water, respectively.

[0071] Example 1 Preparation of CD-PU / PVA composite hydrogel

[0072] Step 1. Preparation of CD-PU aqueous emulsion

[0073] IPDI (0.03 mol) and PTMEG (0.006 mol) were placed in a three-necked flask, and stirred at 85°C for 30 min under nitrogen. After adding 2 drops of stannous octoate, the mixture was stirred at 85°C for 2 h to obtain a mixed solution. 1.021 g of CD (0.0009 mol) dissolved in DMF (4 mL) was added dropwise into the mixed solution, and stirred at 70°C for 1 h. Then, 1.086 g of DMPA (0.0081 mol) dissolved in DMF (4 mL) was added dropwise, and stirred at 65°C for 2 h to obtain a prepolymer solution. The prepolymer solution was emulsified in an aqueous solution containing triethylamine (0.82 g of triethylamine (0.0081 mol) and 50.39 g of water), and stirred at room temperature for 2 h to obtain a CD-PU aqueous emulsion with a solid content of 30 wt.%.

[0074] Step 2. Preparation of PVA aqueous solution

[0075] PVA (9 g) was placed in deionized water (21 g), and stirred at 95°C for 6 h to form a PVA aqueous solution.

[0076] Step 3. 10 g of the CD-PU aqueous emulsion was mixed with the PVA aqueous solution, and stirred uniformly before being poured into a mold to prepare a CD-PU / PVA hydrogel material by freeze-thaw cycles. The freezing temperature was -20°C, and the freezing time was 12 h each time. The thawing temperature was 25°C, and the freeze-thaw cycles were 10 times.

[0077] Example 2 Preparation of CD-PU / PVA composite hydrogel

[0078] Step 1. Preparation of CD-PU aqueous emulsion

[0079] Into a three neck flask, 7.56 g of IPDI (0.034 mol) and 8 g of PTMEG (0.004 mol) were placed and stirred at 75 °C for 30 min under nitrogen. After adding 2 drops of stannous octoate, the mixture was stirred at 75 °C for another 3 h to obtain a mixed solution. Into the mixed solution, 0.57 g of CD (0.0005 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 60 °C for 2 h. Then, 0.54 g of DMPA (0.004 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 55 °C for 3 h to obtain a prepolymer solution. Into the prepolymer solution, an aqueous solution containing triethylamine (triethylamine 0.40 g (0.004 mol), water 96.7 g) was added and emulsified, and stirred at room temperature for 2 h to obtain a CD-PU aqueous emulsion with a solid content of 15 wt.%.

[0080] Step 2. Preparation of PVA aqueous solution

[0081] Into a three neck flask, 7.56 g of IPDI (0.034 mol) and 8 g of PTMEG (0.004 mol) were placed and stirred at 75 °C for 30 min under nitrogen. After adding 2 drops of stannous octoate, the mixture was stirred at 75 °C for another 3 h to obtain a mixed solution. Into the mixed solution, 0.57 g of CD (0.0005 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 60 °C for 2 h. Then, 0.54 g of DMPA (0.004 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 55 °C for 3 h to obtain a prepolymer solution. Into the prepolymer solution, an aqueous solution containing triethylamine (triethylamine 0.40 g (0.004 mol), water 96.7 g) was added and emulsified, and stirred at room temperature for 2 h to obtain a CD-PU aqueous emulsion with a solid content of 15 wt.%.

[0082] Step 3. 10 g of CD-PU aqueous emulsion was mixed with the PVA aqueous solution, and then poured into a mold after being stirred uniformly to obtain a CD-PU / PVA hydrogel material by freeze-thaw cycles. The freezing temperature was -30 °C, and the freezing time was 6 h each time. The thawing temperature was 20 °C, and the freeze-thaw cycles were 9 times.

[0083] Example 3. Preparation of CD-PU / PVA composite hydrogel

[0084] Step 1. Preparation of CD-PU aqueous emulsion

[0085] Into a three neck flask, 7.56 g of IPDI (0.034 mol) and 8 g of PTMEG (0.004 mol) were placed and stirred at 75 °C for 30 min under nitrogen. After adding 2 drops of stannous octoate, the mixture was stirred at 75 °C for another 3 h to obtain a mixed solution. Into the mixed solution, 0.57 g of CD (0.0005 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 60 °C for 2 h. Then, 0.54 g of DMPA (0.004 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 55 °C for 3 h to obtain a prepolymer solution. Into the prepolymer solution, an aqueous solution containing triethylamine (triethylamine 0.40 g (0.004 mol), water 96.7 g) was added and emulsified, and stirred at room temperature for 2 h to obtain a CD-PU aqueous emulsion with a solid content of 15 wt.%.

[0086] Step 2. Preparation of PVA aqueous solution

[0087] Prepare a PVA aqueous solution by placing 10 g of PVA in 10 g of deionized water and stirring at 98 °C for 2 h.

[0088] Step 3. Prepare a CD-PU / PVA hydrogel material by mixing 10 g of the CD-PU aqueous emulsion with the PVA aqueous emulsion, pouring the mixture into a mold after stirring, and subjecting the mixture to freeze-thaw cycles. The freezing temperature is -10 °C, the freezing time is 24 h each time, the thawing temperature is 25 °C, and the number of freeze-thaw cycles is 15.

[0089] Example 4. Preparation of a CD-PU / PVA composite hydrogel

[0090] Step 1. Prepare a CD-PU aqueous emulsion

[0091] Place 8.89 g of IPDI (0.04 mol) and 10 g of PTMEG (0.005 mol) in a three-necked flask, purge with nitrogen, and stir at 80 °C for 20 min. Add 2 drops of stannous octoate and continue stirring at 80 °C for 3 h to obtain a mixed solution. Add 2.84 g of CD (0.0025 mol) dissolved in DMF (4 mL) dropwise to the mixed solution, and stir at 75 °C for 1.5 h. Then add 1.88 g of DMPA (0.014 mol) dissolved in DMF (4 mL) dropwise, and stir at 60 °C for 1.5 h to obtain a prepolymer solution. Emulsify the prepolymer solution in an aqueous solution containing triethylamine (1.42 g of triethylamine (0.014 mol) and 75.1 g of water), and stir at room temperature for 2 h to obtain a CD-PU aqueous emulsion with a solid content of 25 wt.%.

[0092] Step 2. Prepare a PVA aqueous solution

[0093] Prepare a PVA aqueous solution by placing 4 g of PVA in 12 g of deionized water and stirring at 95 °C for 6 h.

[0094] Step 3. Prepare a CD-PU / PVA hydrogel material by mixing 10 g of the CD-PU aqueous emulsion with the PVA aqueous emulsion, pouring the mixture into a mold after stirring, and subjecting the mixture to freeze-thaw cycles. The freezing temperature is -25 °C, the freezing time is 24 h each time, the thawing temperature is 25 °C, and the number of freeze-thaw cycles is 15.

[0095] Example 5. Preparation of a CD-PU / PVA composite hydrogel

[0096] Step 1. Prepare a CD-PU aqueous emulsion

[0097] 6.67 g IPDI (0.03 mol) and 30 g PTMEG (0.015 mol) were placed in a three-necked flask, purged with nitrogen, and stirred at 90°C for 15 minutes. Two drops of stannous octoate were added, followed by further stirring at 90°C for 2.5 hours to obtain a mixed solution. 1.02 g CD (0.0009 mol) dissolved in DMF (4 mL) was added dropwise to the mixed solution, stirred at 65°C for 1 hour, and then 1.88 g DMPA (0.014 mol) dissolved in DMF (4 mL) was added dropwise and stirred at 70°C for 2 hours to obtain a prepolymer solution. An aqueous solution containing triethylamine (1.42 g (0.014 mol) of triethylamine and 61.48 g of water) was added to the prepolymer solution and emulsified. The mixture was stirred at room temperature for 2 hours to obtain an aqueous cyclodextrin-grafted polyurethane (CD-PU) emulsion with a solids content of 40 wt.%.

[0098] Step 2. Preparation of PVA aqueous solution

[0099] 10 g of PVA was placed in 18.5 g of deionized water and stirred at 95 °C for 6 h to form a PVA aqueous solution.

[0100] Step 3. Mix 10g of the CD-PU emulsion and the PVA emulsion, stir thoroughly, pour into a mold, and freeze-thaw repeatedly to produce the CD-PU / PVA hydrogel. The freezing temperature was -15°C, and each freezing time was 12 hours. The thawing temperature was 25°C, and the freeze-thaw cycle was repeated 12 times.

[0101] Example 6 Preparation of CD-PU / PVA Composite Hydrogel

[0102] Step 1. Preparation of cyclodextrin grafted polyurethane (CD-PU) aqueous emulsion

[0103] 6.67g IPDI (0.03mol) and 12g PTMEG (0.006mol) were placed in a three-necked flask, purged with nitrogen, and stirred at 85°C for 30 minutes. Two drops of stannous octoate were added, followed by stirring at 85°C for 2 hours to obtain a mixed solution. 0.5675g CD (0.0005mol) dissolved in DMF (4mL) was added dropwise to the mixed solution, stirred at 70°C for 1 hour, and then 1.811g DMPA (0.0135mol) dissolved in DMF (4mL) was added dropwise, stirred at 65°C for 2 hours to obtain a prepolymer solution. An aqueous solution containing triethylamine (1.366g (0.0135mol) triethylamine and 52.3g water) was added to the prepolymer solution for emulsification, and stirred at room temperature for 2 hours to obtain a cyclodextrin-grafted polyurethane (CD-PU) aqueous emulsion with a solids content of 30 wt.%.

[0104] Step 2. Same as step 2 in Example 1.

[0105] Step 3. Same as step 3 in Example 1.

[0106] Example 7 Preparation of CD-PU / PVA Composite Hydrogel

[0107] Step 1. Preparation of cyclodextrin grafted polyurethane (CD-PU) aqueous emulsion

[0108] 6.67g IPDI (0.03mol) and 12g PTMEG (0.006mol) were placed in a three-necked flask, purged with nitrogen, and stirred at 85°C for 30 minutes. Two drops of stannous octoate were added, followed by stirring at 85°C for 2 hours to obtain a mixed solution. 2.043g CD (0.0018mol) dissolved in DMF (4mL) was added dropwise to the mixed solution, stirred at 70°C for 1 hour, and then 0.966g DMPA (0.0072mol) dissolved in DMF (4mL) was added dropwise, stirred at 65°C for 2 hours to obtain a prepolymer solution. An aqueous solution containing triethylamine (0.729g (0.0072mol) triethylamine and 52.28g water) was added to the prepolymer solution for emulsification, and stirred at room temperature for 2 hours to obtain a cyclodextrin-grafted polyurethane (CD-PU) aqueous emulsion with a solids content of 30 wt.%.

[0109] Step 2. Same as step 2 in Example 1.

[0110] Step 3. Same as step 3 in Example 1.

[0111] Comparative Example 1 Preparation of PVA hydrogel

[0112] 9 g of PVA was placed in 21 g of deionized water and stirred at 95° C. for 6 h to form a PVA aqueous solution.

[0113] The above solution was poured into a mold and subjected to 10 freeze-thaw cycles to prepare a PVA hydrogel. The freezing temperature was -20°C, each freezing time was 12 hours, and the thawing temperature was 25°C.

[0114] Comparative Example 2 Preparation of PU / PVA hydrogel

[0115] 6.67 g IPDI (0.03 mol) and 12 g PTMEG (0.006 mol) were placed in a three-necked flask, purged with nitrogen, and stirred at 85° C. for 30 min. 2 drops of stannous octoate were added and stirring was continued for 2 h to obtain a mixed solution.

[0116] 1.21 g DMPA (0.009 mol) dissolved in DMF (4 mL) was added dropwise to the mixture and stirred at 65 °C for 2 h to obtain a prepolymer solution;

[0117] The prepolymer solution was added to an aqueous solution containing triethylamine (0.91 g (0.009 mol) of triethylamine and 48.51 g of water) and emulsified, and stirred at room temperature for 2 h to obtain a PU aqueous emulsion with a solid content of 30 wt.%.

[0118] 10g of the PU aqueous emulsion was mixed with the PVA aqueous solution prepared according to Comparative Example 1, stirred thoroughly, and poured into a mold. The mixture was then freeze-thawed 10 times to produce a PU / PVA hydrogel. The freezing temperature was -20°C for 12 hours per freeze; the thawing temperature was 25°C.

[0119] Test Example 1

[0120] This test example investigated the mechanical properties of the CD-PU / PVA composite hydrogels prepared in Examples 1, 6, and 7, the PVA hydrogel prepared in Comparative Example 1, and the PU / PVA hydrogel prepared in Comparative Example 2. In the CD-PU / PVA composite hydrogels of Examples 1, 6, and 7, the molar ratios of CD:(PDI+PTMEG+CD+DMPA) were 2:100, 1:100, and 4:100, respectively. Therefore, the CD-PU / PVA composite hydrogels of Examples 1, 6, and 7 were designated as 2% CD-PU / PVA hydrogel, 1% CD-PU / PVA hydrogel, and 4% CD-PU / PVA hydrogel, respectively.

[0121] The specific operations of this test example are as follows:

[0122] 1. Mechanical compression curve investigation

[0123] The compression performance of different PVA, PU / PVA, and CD-PU / PVA hydrogels was tested using a universal mechanical testing machine. Specifically, the hydrogels were made into cylindrical samples with dimensions of Φ×h=10mm×15mm and compressed at a rate of 1mm / min until the sample deformation was 50%. The compression stress-strain curves were obtained. The results are shown in the attached figure. Figure 1 shown.

[0124] By the attached Figure 1 It can be seen that the compressive stress of the three hydrogels gradually increases with the increase of strain. When the compressive strain is 50%, the compressive strength of the hydrogel is: 4%CD-PU / PVA>2%CD-PU / PVA>1%CD-PU / PVA>PU / PVA>PVA, indicating that the double-network hydrogel formed by introducing PU into PVA can effectively enhance the mechanical strength of the material; the CD-PU / PVA hydrogel formed by CD grafting PU has higher mechanical strength. This is because CD can effectively disperse stress in the gel network structure through its own structural characteristics (slip ring structure), giving the hydrogel structural stability.

[0125] 2. Investigation of mechanical compression modulus

[0126] Combined with the compression stress-strain curves, the compression modulus of PVA, PU / PVA, CD-PU / PVA hydrogels were calculated, and the results were shown in Fig. 2. From Fig. 2, it can be seen that the compression modulus of the hydrogels was: CD-PU / PVA > PU / PVA > PVA, in which the compression modulus of CD-PU / PVA was 4.81 MPa, which was close to the compression modulus of natural articular disc of human tissue. Figure 2 Figure 2

[0127] 3. Investigation of mechanical tensile curve

[0128] The mechanical tensile properties of PVA, PU / PVA, CD-PU / PVA hydrogels were tested by using a universal mechanical testing machine. The hydrogels were cut into dumbbell-shaped (l x w x h = 75 mm x 4 mm x 2 mm) samples, and a layer of silicone oil was applied to the surface of the samples to prevent water evaporation in the gel from affecting the experimental results. Then the samples were fixed between the clamps, and the tensile test was carried out after the parameter setting, and the specific parameter setting was as follows: the initial distance between the clamps was 20 mm, and the loading rate was 20 mm / min. The measured tensile stress-strain curves were shown in Fig. 3. From Fig. 3, it can be seen that the tensile stress of the three hydrogels gradually increased with the increase of strain, and the CD-PU / PVA hydrogel had a larger critical tensile strain and higher tensile strength, because the grafting of CD was beneficial to the deformation of the composite hydrogel during the tensile process, and the CD-PU molecular chain as a flexible molecular chain could effectively disperse the stress and avoid stress concentration, giving the material higher mechanical tensile strength. Figure 3 Figure 3

[0129] 4. Investigation of mechanical tensile breaking energy and breaking elongation

[0130] Combined with the tensile stress-strain curves, the breaking elongation and breaking energy of PVA, PU / PVA, CD-PU / PVA hydrogels were calculated, and the results were shown in Fig. 4. From Fig. 4, it can be seen that the CD-PU / PVA hydrogel had a higher breaking elongation, because the special ring structure of CD in CD-PU acted as a sliding ring during the tensile process, allowing the molecular chain to slide freely and avoiding the molecular chain rupture caused by stress concentration. At the same time, the CD-PU / PVA hydrogel had a higher breaking energy, indicating that the toughness of the CD-PU / PVA hydrogel was stronger, which played a positive role in improving the service life of the artificial synthetic articular disc material. Figure 4 Figure 4

[0131] ​​​​​​5. Tensile cycle test The mechanical tensile cycle performance of 2% CD-PU / PVA hydrogel was tested using a universal mechanical testing machine. The sample was stretched to 50%, 100%, 150%, 200%, 250%, 300%, 350% of the original length at a rate of 2 mm / min, respectively, and unloaded to 0 N at the same rate after each stretching was completed. The elastic modulus loss of the material was calculated in combination with the tensile cycle stress-strain curve. The results are shown in FIG. 2. Among them Figure 5 Cycle1, Cycle2, Cycle3, Cycle4, Cycle5, Cycle6 and Cycle7 in FIG. 2 represent the loading-unloading tensile curves of the tensile strain of 50%, 100%, 150%, 200%, 250%, 300%, 350%, respectively. Figure 5

[0132] It can be seen from FIG. 2 that the CD-PU / PVA hydrogel exhibits hysteresis during the tensile cycle process, and the modulus loss of the material is relatively small after each cycle, indicating that the material has good structural stability and fatigue resistance. Figure 6

[0133] 6. Friction and wear test curve

[0134] The friction and wear properties of PVA and CD-PU / PVA hydrogel prepared in Example 1 were tested using a ball-on-disc friction tester. The hydrogel was fixed at the bottom of the instrument, and physiological saline was immersed to simulate the in-vivo liquid environment; a GCr15 steel ball (diameter 8 mm) was used for friction and wear testing. The test sliding distance of each group of materials was 5 mm, the frequency was 1 Hz, the load was 5 N, and the time was 2 h (a total of 7200 cycles), and the results are shown in FIG. 3. It can be seen from FIG. 3 that the friction and wear coefficient of the CD-PU / PVA hydrogel is stable near 0.1, and the material surface is smooth without obvious scratches after 7200 times of friction and wear, indicating that the surface material has good friction and wear properties. Figure 7 Figure 7

[0135] Test Example 2

[0136] In this test example, the biological properties of CD-PU / PVA composite hydrogel prepared in Example 1 and PVA hydrogel prepared in Comparative Example 1 were investigated. Specifically as follows:

[0137] 1. Biocompatibility investigation

[0138] The sterilized PVA and 2% CD-PU / PVA hydrogel were placed in a 24-well plate containing 1 mL of DMEM medium and placed in a 37°C constant temperature incubator overnight. After removing the culture medium, 1 mL of 5 x 105L929 cells were added to each well, and the cells were cultured for 3 days. The culture medium was removed and the cells were fixed with 4% paraformaldehyde for 10 min. After washing with PBS, 1 mL of 0.1% crystal violet was added to each well, and the cells were stained for 10 min. After washing with PBS, the number of cells was counted under a microscope. The results are shown in FIG. 4. 3 ​​​​The articular disc cells are added into the holes and placed in a culture box for culture. The liquid is changed every 2-3 days. After the articular disc cells are co-cultured with the materials for 1 day, 3 days and 5 days respectively, the cell viability is determined by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, MTT) method to investigate the cell growth and survival. The original culture medium in the hole plate is removed, 1 mL of fresh culture medium and 40 μL of MTT are added, and the mixture is incubated in a 37°C constant temperature incubator for 4 hours to form formazan crystals. Then, the mixture is removed, 500 μL of DMSO is added and shaken until the formazan crystals are dissolved, and the absorbance value of the solution is determined at 570 nm by an enzyme-labeled instrument.

[0139] The experimental results are shown in Table 1. Figure 8 As shown in Table 1, the results show that the articular disc cells co-cultured with the CD-PU / PVA hydrogel present a cell proliferation trend with the change of time, and no cell proliferation inhibition phenomenon occurs compared with the blank control group, indicating that the material has good cell biocompatibility.

[0140] 2. Hemolysis performance evaluation of the material.

[0141] 1 mL of rabbit blood is taken in an Ep tube, and the red blood cells in the serum are collected by centrifugation; a small amount of red blood cells is diluted in simulated body fluid (PBS) to obtain a red blood cell solution with a volume ratio of 5%; then, 0.1 g of 2% CD-PU / PVA hydrogel material is added into 200 μL of the red blood cell solution, and centrifuged after incubation in an incubator for 1 hour; 100 μL of the centrifugal supernatant is taken in a 96-well plate, and the absorbance value at 540 nm is measured by an enzyme-labeled instrument, and the hemolysis of the material is calculated. In this experiment, PBS and 0.1% Triton are selected as negative and positive controls respectively.

[0142] Hemolysis rate = (Vs-Vn) / (Vp-Vn) x 100%

[0143] Wherein, Vs, Vn, Vp represent the absorbance values of the experimental sample group, the negative control group and the positive control group respectively.

[0144] The experimental results are shown in Table 1. Figure 9 As shown in Table 1, the results show that the hemolysis rate of 2% CD-PU / PVA hydrogel is 1.88%, which meets the standard requirement of less than 5% for the hemolysis rate of biological medical materials in China.

[0145] The above-described embodiments are part of the embodiments of the present application, rather than all the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair, characterized in that: The steps include: S1. Preparation of cyclodextrin-grafted polyurethane aqueous emulsion; S2 preparation of polyvinyl alcohol aqueous solution: polyvinyl alcohol was added to water, stirred under heating conditions to obtain a polyvinyl alcohol aqueous solution; S3. The cyclodextrin-grafted polyurethane aqueous emulsion was mixed with an aqueous solution of polyvinyl alcohol, stirred evenly, and subjected to freeze-thaw cycles to obtain a composite hydrogel; the mass ratio of the solid mass of the cyclodextrin-grafted polyurethane aqueous emulsion to the mass of polyvinyl alcohol was 1:1-1:3; The step S1 comprises the following steps: S11 isophorone diisocyanate and polytetramethylene ether diol were mixed, heated with stirring under inert gas conditions, the catalyst was added, and heating with stirring was continued; S12 β-cyclodextrin grafting modification: β-cyclodextrin was added to the solution prepared in step S11, heated and stirred, and grafted; S13 chain extension: adding a chain extender to the solution prepared in step S12 for chain extension, heating and stirring to obtain a prepolymer solution; S14 neutralization emulsification: adding a neutralizing agent to the prepolymer solution prepared in step S13 and emulsifying, stirring to form a cyclodextrin grafted polyurethane aqueous emulsion; The molar ratio of each substance is as follows: β-cyclodextrin: (isophorone diisocyanate + polytetramethylene ether glycol + β-cyclodextrin + chain extender) = 1:100~4:

100.

2. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: Chain extenders include 2,2-dimethylolpropionic acid.

3. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: The molar ratios of each substance are as follows: Isophorone diisocyanate: (polytetramethylene ether glycol + β-cyclodextrin + chain extender) = 4:1~1:1; Polytetramethylene ether glycol: (β-cyclodextrin + chain extender) = 1:1-1:

3.

4. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 3, characterized in that: Isophorone diisocyanate: (polytetramethylene ether glycol + β-cyclodextrin + chain extender) = 2:

1.

5. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 3, characterized in that: Polytetramethylene ether glycol: (β-cyclodextrin + chain extender) = 1:1.

5.

6. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 3, characterized in that: β-cyclodextrin: (isophorone diisocyanate + polytetramethylene ether glycol + β-cyclodextrin + chain extender) = 2:

100.

7. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: In step S11, isophorone diisocyanate and polytetramethylene ether glycol are mixed and heated and stirred at 75-95° C.; the stirring time is 10-30 minutes.

8. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 7, characterized in that: In step S11, isophorone diisocyanate and polytetramethylene ether glycol are mixed and heated and stirred at 85° C.; the stirring time is 20 min.

9. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: In step S11, the catalyst is stannous octoate.

10. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 7, characterized in that: In step S11, after adding the catalyst, heating and stirring are continued at 75-95° C.; the stirring time is 1.5-3 hours.

11. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 7, characterized in that: In step S11, after adding the catalyst, heating and stirring are continued at 85° C. for 2 h.

12. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: In the step S12, a β-cyclodextrin solution is added to the solution prepared in the step S11 for grafting modification.

13. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 12, characterized in that: In step S12, the β-cyclodextrin solution is a β-cyclodextrin N,N-dimethylformamide solution with a concentration of 25-55 w / v%.

14. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 13, characterized in that: In step S12, the concentration of the β-cyclodextrin solution is 27 w / v%.

15. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 12, characterized in that: In step S12, after adding the β-cyclodextrin solution, heating and stirring are carried out at 60-80° C.; the stirring time is 30-120 minutes.

16. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 15, characterized in that: In step S12, the β-cyclodextrin solution is added and heated and stirred at 70° C. for 60 min.

17. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: In the step S13, the chain extender solution is added to the solution prepared in the step S12, and then heated and stirred at 55-75° C.; the stirring time is 1-3 hours.

18. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 17, characterized in that: In the step S13, the chain extender solution is added to the solution prepared in the step S12, and then heated and stirred at 65° C. for 2 hours.

19. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 17, characterized in that: In step S13, the chain extender solution is a solution of 2,2-dimethylolpropionic acid in N,N-dimethylformamide.

20. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 2, characterized in that: In step S14, the neutralizing agent is a triethylamine aqueous solution.

21. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 20, characterized in that: In step S14, the molar ratio of triethylamine to 2,2-dihydroxymethylpropionic acid is 1:

1.

22. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 20, characterized in that: In step S14, the water content of the cyclodextrin-grafted polyurethane aqueous emulsion is 50 wt.% to 85 wt.%.

23. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 20, characterized in that: The water content of the cyclodextrin grafted polyurethane aqueous emulsion is 70 wt.%.

24. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 1, characterized in that: The step S2 of preparing the polyvinyl alcohol aqueous solution is as follows: adding water to polyvinyl alcohol and stirring at 90-98° C. for 2-12 hours to prepare a polyvinyl alcohol aqueous solution with a mass fraction of 15-50%.

25. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: The mass fraction of the polyvinyl alcohol aqueous solution prepared in step S2 is 25-35%.

26. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: The mass fraction of the polyvinyl alcohol aqueous solution prepared in step S2 is 30%.

27. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the mass ratio of the solid mass in the cyclodextrin-grafted polyurethane aqueous emulsion to the polyvinyl alcohol is 1:

3.

28. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: The solid content of the solution obtained by mixing the cyclodextrin grafted polyurethane aqueous emulsion and the polyvinyl alcohol aqueous solution is 20-50%.

29. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: The solid content of the solution obtained by mixing the cyclodextrin grafted polyurethane aqueous emulsion and the polyvinyl alcohol aqueous solution is 30%.

30. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the number of freeze-thaw cycles is 9-15 times.

31. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the number of freezing and thawing is 10 times.

32. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the freezing temperature is -30°C to -10°C.

33. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the freezing temperature is -20°C.

34. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the freezing time is 6-24 hours.

35. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the freezing time is 12 hours.

36. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the thawing temperature is room temperature.

37. The method for preparing a high-strength and toughened composite hydrogel for articular disc replacement / repair according to claim 24, characterized in that: In step S3, the thawing temperature is 25°C.

38. The composite hydrogel prepared according to the preparation method according to any one of claims 1 to 37.

39. Use of the composite hydrogel according to claim 38 in preparing a material for repairing or / and replacing a temporomandibular joint disc.

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