A strontium ion / zoledronic acid-loaded composite gel and a method for preparing the same

Abstract

The application belongs to the technical field of biomedical materials, and provides a composite gel loaded with strontium ions / zoledronic acid and a preparation method thereof, which comprises the following steps: preparing thiol-modified sodium hyaluronate and double bond-modified carboxymethyl chitosan; preparing strontium ion-doped mesoporous silica microspheres, thiol-modified strontium ion-doped mesoporous silica microspheres and thiol-modified strontium ion-doped mesoporous silica microspheres loaded with zoledronic acid in sequence; dissolving the thiol-modified sodium hyaluronate and the double bond-modified carboxymethyl chitosan in deionized water respectively, and then stirring and mixing the thiol-modified sodium hyaluronate, the double bond-modified carboxymethyl chitosan and the thiol-modified strontium ion-doped mesoporous silica microspheres loaded with zoledronic acid, and adding a photoinitiator and irradiating under ultraviolet light. The composite gel prepared by the application integrates mechanical support, biocompatibility, intelligent drug release and synergistic osteogenesis / angiogenesis, and can be applied to the preparation of high-performance osteoporotic bone defect repair materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biomedical materials, and particularly relates to a composite gel loaded with strontium ions / zoledronic acid and a preparation method thereof. BACKGROUND

[0002] Osteoporosis is a systemic bone disease characterized by bone mass loss and bone microstructure destruction, which significantly increases the risk of bone defects in patients. The repair of such osteoporotic bone defects faces severe challenges: on the one hand, the local bone formation ability of patients is severely low, and the osteoblast activity is insufficient; on the other hand, the bone defect area is often accompanied by poor vascularization, and the transportation of nutrients and repair cells is blocked, further delaying the healing process. Traditional bone defect repair materials often fail to meet the special needs of such pathological microenvironments: they either lack effective biological activity to stimulate osteogenesis and vascularization, or cannot provide suitable mechanical support and degradation performance.

[0003] In recent years, the research of functional bone repair materials has focused on the introduction of bioactive factors. Strontium ions have been proven to have a dual promotion effect: they can significantly enhance the differentiation and mineralization ability of osteoblasts, and effectively stimulate endothelial cell proliferation and angiogenesis; as a strong bisphosphonate, zoledronic acid can effectively inhibit the activity of osteoclasts, preventing pathological bone resorption and creating favorable conditions for bone regeneration. In theory, the synergistic effect of strontium ions and zoledronic acid is expected to provide a more optimized treatment for osteoporotic bone defects, however, most studies focus on a single function, or only pay attention to drug delivery itself, lacking an effective integration strategy for active factor delivery and scaffold materials with suitable mechanical properties, which makes it difficult for the material to fill the defect while providing continuous biological stimulation and stable physical support for bone healing. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a preparation method of a composite gel loaded with strontium ions / zoledronic acid, aiming to solve the problems raised in the background art.

[0005] The embodiments of the present application are implemented in the following way: a preparation method of a composite gel loaded with strontium ions / zoledronic acid, comprising the following steps:

[0006] Sodium hyaluronate is dissolved in deionized water to obtain a sodium hyaluronate solution, and solid cysteamine hydrochloride is added to obtain thiol-modified sodium hyaluronate;

[0007] Carboxymethyl chitosan is dissolved in deionized water to obtain a carboxymethyl chitosan solution, and liquid glycidyl methacrylate is added to obtain double bond-modified carboxymethyl chitosan;

[0008] Cetyl trimethyl ammonium bromide and ammonia water are dissolved in deionized water to obtain a mixed solution, tetraethyl orthosilicate and strontium chloride hexahydrate are added to obtain mesoporous silica microspheres doped with strontium ions;

[0009] The mesoporous silica microspheres doped with strontium ions are dispersed into a toluene solution, and 3-mercaptopropyl trimethoxysilane is added to obtain mercapto-modified mesoporous silica microspheres doped with strontium ions;

[0010] The mercapto-modified mesoporous silica microspheres doped with strontium ions are dispersed into deionized water, and solid zoledronic acid is added to obtain mercapto-modified mesoporous silica microspheres doped with strontium ions loaded with zoledronic acid;

[0011] Sodium hyaluronate modified by mercapto and double bond modified carboxymethyl chitosan are respectively dissolved in deionized water to obtain precursor solutions A and B; precursor solutions A, B and the mercapto-modified mesoporous silica microspheres doped with strontium ions loaded with zoledronic acid are fully stirred and mixed, a photoinitiator is added, and irradiation is performed under ultraviolet light to form a composite gel loaded with strontium ions / zoledronic acid.

[0012] Another purpose of the embodiment of the present application is to provide a composite gel loaded with strontium ions / zoledronic acid, which is prepared by the above preparation method.

[0013] Another purpose of the embodiment of the present application is to provide an application of the composite gel loaded with strontium ions / zoledronic acid in the preparation of bone defect repair materials.

[0014] The composite gel loaded with strontium ions / zoledronic acid provided by the embodiment of the present application integrates mechanical support, biocompatibility, intelligent drug release, and synergistic bone promotion / vascularization, and can be applied in the preparation of high-performance osteoporotic bone defect repair materials, and creatively solves the key bottleneck of insufficient comprehensive performance of repair materials.

[0015] The embodiment of the present application utilizes the mercapto-double bond click chemistry reaction between the mercapto-modified sodium hyaluronate and the double bond-modified carboxymethyl chitosan, realizes rapid and stable crosslinking under 365nm ultraviolet light, and the light-triggered crosslinking strategy overcomes the defects of uncontrollable traditional chemical crosslinking and slow biological crosslinking, and can accurately form in situ, thereby providing persistent mechanical support for bone defect filling;

[0016] The embodiment of the present application creatively prepares strontium ion doped mesoporous silica microspheres, the introduction of strontium ions is not simply added, but realizes the synergistic effect of double biological effects: on the one hand, strontium ions can be continuously released to effectively stimulate the activity of osteoblasts, and significantly enhance the bone induction of the material; on the other hand, it can simultaneously and significantly promote the neovascularization of the bone defect area; this "osteogenesis-vascularization coupling" property is crucial to solve the problems of low bone formation ability and insufficient local blood supply commonly existing in osteoporosis patients, thereby accelerating the bone healing process;

[0017] The embodiment of the present application creatively prepares strontium ion doped mesoporous silica microspheres, the introduction of strontium ions is not simply added, but realizes the synergistic effect of double biological effects: on the one hand, strontium ions can be continuously released to effectively stimulate the activity of osteoblasts, and significantly enhance the bone induction of the material; on the other hand, it can simultaneously and significantly promote the neovascularization of the bone defect area; this "osteogenesis-vascularization coupling" property is crucial to solve the problems of low bone formation ability and insufficient local blood supply commonly existing in osteoporosis patients, thereby accelerating the bone healing process;

[0018] The composite gel prepared in the embodiment of the present application can realize the double regulation of promoting osteogenesis, that is, while the zoledronic acid inhibits osteoclasts, the strontium ions continuously promote the differentiation of osteoblasts, forming a dynamic balance of "anti-absorption-promotion", which will be significantly better than the treatment strategy of a single drug. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The flow chart of the preparation method of the composite gel loaded with strontium ions / zoledronic acid provided in the embodiment of the present application;

[0020] Figure 2 The Fourier infrared spectrum of the composite gel material obtained in the comparative example 1 of the present application; HA is sodium hyaluronate; HA-SH is thiol-modified sodium hyaluronate; CMCS is carboxymethyl chitosan; CMCS-GMA is double bond modified carboxymethyl chitosan; HSCG is a composite gel generated by the reaction of HA-SH and CMCS-GMA;

[0021] Figure 3 The scanning electron microscope graph of the composite gel loaded with strontium ions / zoledronic acid obtained in the embodiment 1 of the present application;

[0022] Figure 4 The transmission electron microscope graph of the mesoporous silica microspheres loaded with zoledronic acid and thiol-modified and strontium ion doped obtained in the embodiment 1 of the present application;

[0023] Figure 5 The particle size distribution graph of the microspheres obtained in steps S4 and S5 in the embodiment 1 of the present application, respectively;

[0024] Figure 6Modulus-amplitude scanning graphs of the composite gels obtained in Examples 1-3 and Comparative Example 1 of the present application;

[0025] Figure 7 Stress-strain curves of the compression strength of the composite gels obtained in Examples 1-3 and Comparative Example 1 of the present application;

[0026] Figure 8 Comparison graphs of the results of BMSC cell proliferation experiments of the composite gels obtained in Examples 1-3 and Comparative Example 1 of the present application;

[0027] Figure 9 Comparison graphs of the results of HUVEC cell angiogenesis experiments of the composite gels obtained in Examples 1-3 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0029] The specific implementation of the present application is described in detail below in combination with specific examples.

[0030] Example 1, a composite gel loaded with strontium ions / zoledronic acid, the preparation method of which is shown in Figure 1 and specifically includes the following steps:

[0031] Step S1, dissolve 1 g of sodium hyaluronate with a molecular weight of 1.0-1.8 MDa (HA) in 100 mL of deionized water, and magnetically stir until completely dissolved to obtain a sodium hyaluronate solution; add 955 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 575 mg of N-hydroxysuccinimide to the obtained solution in sequence, and magnetically stir until completely dissolved; add 283 mg of cysteamine hydrochloride to the above obtained mixed solution, and magnetically stir in a dark environment at 25°C for 24 h; pack the obtained mixed solution into a dialysis bag, dialyze with deionized water for 7 days, and freeze-dry at -80°C for 3 days to obtain thiol-modified sodium hyaluronate (HA-SH);

[0032] Step S2, dissolve 1 g of carboxymethyl chitosan (CMCS) in 100 mL of deionized water, and magnetically stir until completely dissolved to obtain a carboxymethyl chitosan solution; add 1 mL of glycidyl methacrylate to the obtained solution, and magnetically stir until uniformly mixed, and magnetically stir in a dark environment at 25°C for 24 h; pack the obtained mixed solution into a dialysis bag, dialyze with deionized water for 7 days, and freeze-dry at -80°C for 3 days to obtain double bond-modified carboxymethyl chitosan (CMCS-GMA);

[0033] Step S3, 0.728 g of cetyltrimethylammonium bromide and 2 mL of aqueous ammonia were sequentially added to 100 mL of deionized water, and magnetically stirred until completely dissolved (magnetic stirring at 40°C for 1 h); 4.167 g of tetraethyl orthosilicate and 0.34 g of strontium chloride hexahydrate were sequentially added to the above obtained mixed solution, and magnetically stirred until mixed uniformly (magnetic stirring at 40°C for 5 h); the organic solvent was removed, and the nanoparticles were collected by centrifugation at 10,000 rpm for 10 min, washed with ethanol and deionized water alternately for three times, and then placed in a vacuum drying oven, and dried at 60°C for 24 h under vacuum; the obtained product was placed in a tube furnace, heated to 700°C at a heating rate of 2°C / min, and calcined for 3 h to remove excess cetyltrimethylammonium bromide, to obtain mesoporous silica microspheres doped with strontium ions (MSN / Sr);

[0034] Step S4, 150 mg of dried mesoporous silica microspheres doped with strontium ions were placed in a vacuum oven, activated at 80°C for 12 h; 150 mg of the activated mesoporous silica microspheres doped with strontium ions were dispersed in 30 mL of toluene, and magnetically stirred until the particles were uniformly distributed; 0.2 mL of 3-mercaptopropyltrimethoxysilane was slowly added to the above solution, and refluxed at 110°C for 24 h under condensation; the organic solvent was removed, and the nanoparticles were collected by centrifugation at 10,000 rpm for 10 min, washed with ethanol and deionized water alternately for three times, and then placed in a vacuum drying oven, and dried at 60°C for 24 h under vacuum, to obtain mercapto-modified mesoporous silica microspheres doped with strontium ions;

[0035] Step S5, 500 mg of dried mercapto-modified mesoporous silica microspheres doped with strontium ions were dispersed in 200 mL of deionized water, and magnetically stirred until the particles were uniformly distributed; 200 mg of zoledronic acid was added to the above mixed solution, and magnetically stirred until completely dissolved, and magnetically stirred at 25°C for 6 h; the solution was removed, and the nanoparticles were collected by centrifugation at 10,000 rpm for 10 min, washed with water and ethanol alternately for three times, and then freeze-dried at -80°C for 3 days, to obtain mercapto-modified mesoporous silica microspheres doped with strontium ions loaded with zoledronic acid (MSN / Sr / ZA);

[0036] Step S6, the mercapto-modified sodium hyaluronate obtained in step S1 and the double bond-modified carboxymethyl chitosan obtained in step S2 were separately dissolved in deionized water to obtain precursor solutions A and B; precursor solutions A, B and the microspheres obtained in step S5 were thoroughly stirred and mixed, and a photoinitiator was added, and irradiated under ultraviolet light; the volume ratio of precursor solutions A and B was 1:4, the concentration of the microspheres was 0.1% (w / v), the wavelength of the ultraviolet light was 365 nm, 0.5% (w / v) of the photoinitiator was added, and the irradiation time was 1 min, to obtain a composite gel loaded with strontium ions / zoledronic acid (named as HSCG@MSN / Sr / ZA).

[0037] Example 2, a composite gel loaded with strontium ions, the preparation method comprising the following steps:

[0038] Steps S1-S4: the same as steps S1-S4 in Example 1;

[0039] Step S5, the thiol-modified sodium hyaluronate obtained in step S1 and the double bond-modified carboxymethyl chitosan obtained in step S2 are respectively dissolved in deionized water to obtain precursor solutions A and B; the precursor solutions A, B and the microspheres obtained in step S4 are fully stirred and mixed, a photoinitiator is added, and irradiation is performed under ultraviolet light; the volume ratio of the precursor solutions A and B is 1:4, the concentration of the microspheres is 0.1% (w / v), the wavelength of the ultraviolet light is 365 nm, 0.5% (w / v) of the photoinitiator is added, the irradiation time is 1 min, and a carboxymethyl chitosan photocrosslinked sodium hyaluronate composite gel loaded with strontium ions (named as HSCG@MSN / Sr) is obtained.

[0040] Example 3, a composite gel loaded with zoledronic acid, the preparation method comprising the following steps:

[0041] Steps S1-S2: the same as steps S1-S2 in Example 1;

[0042] Step S3, the thiol-modified sodium hyaluronate obtained in step S1 and the double bond-modified carboxymethyl chitosan obtained in step S2 are respectively dissolved in deionized water to obtain precursor solutions A and B; the precursor solutions A, B and the zoledronic acid are fully stirred and mixed, a photoinitiator is added, and irradiation is performed under ultraviolet light; the volume ratio of the precursor solutions A and B is 1:4, the concentration of the zoledronic acid is 0.1% (w / v), 0.5% (w / v) of the photoinitiator is added, the wavelength of the ultraviolet light is 365 nm, the irradiation time is 1 min, and a carboxymethyl chitosan photocrosslinked sodium hyaluronate composite gel loaded with zoledronic acid (named as HSCG@ZA) is obtained.

[0043] Example 4, compared with Example 1, the difference lies in that the volume ratio of the precursor solutions A and B in step S6 is adjusted to 1:3.

[0044] Example 5, compared with Example 1, the difference lies in that the volume ratio of the precursor solutions A and B in step S6 is adjusted to 1:2.

[0045] Comparative Example 1, a gel, the preparation method specifically comprising the following steps:

[0046] Steps S1-S2, the same as steps S1-S2 in Example 1;

[0047] Step S3, the thiol-modified sodium hyaluronate obtained in step S1 and the double bond-modified carboxymethyl chitosan obtained in step S2 are dissolved in deionized water respectively to obtain precursor solutions A and B; precursor solutions A and B are mixed by fully stirring, a photoinitiator is added, and the precursor solution A and B mixture is irradiated under ultraviolet light, the volume ratio of the precursor solution A and B is 1:4; 0.5% (w / v) of the photoinitiator is added, the ultraviolet light wavelength is 365 nm, and the light irradiation time is 1 min to obtain a carboxymethyl chitosan photo-crosslinked sodium hyaluronate composite gel (named as HSCG).

[0048] Performance analysis and test:

[0049] The gel obtained in Comparative Example 1 is subjected to a total reflection infrared spectrum test, and the results are shown in Figure 2 The figure shows that HA is sodium hyaluronate; HA-SH is thiol-modified sodium hyaluronate; CMCS is carboxymethyl chitosan; CMCS-GMA is double bond-modified carboxymethyl chitosan; HSCG is a composite gel generated by the reaction of HA-SH and CMCS-GMA; it can be seen that the characteristic peak of -HN-CO- at 1546 cm -1 is more obvious after the thiolization reaction; the characteristic peak of -C=O- at 1715 cm -1 appears in the infrared spectrum of the double bond-modified carboxymethyl chitosan; the characteristic peak of -C-S- at 765 cm -1 appears in the infrared spectrum of the HSCG composite gel, confirming the successful preparation of the composite gel HSCG.

[0050] The strontium ion / zoledronic acid-loaded composite gel obtained in Example 1 is subjected to field emission electron microscope scanning, and the results are shown in Figure 3 It can be seen that the gel presents an irregular porous microstructure, and obvious microspheres can be observed in the pores.

[0051] The thiol-modified strontium ion-doped mesoporous silica microspheres loaded with zoledronic acid obtained in Example 1 are subjected to field emission transmission electron microscope scanning, and the results are shown in Figure 4 It can be seen that the modified mesoporous silica microspheres still maintain the mesoporous structure and are still nanoscale in size.

[0052] The particle sizes of the microspheres obtained in step S4 and step S5 of Example 1 are analyzed, and the results are shown in Figure 5 The average particle size of the thiol-modified strontium ion-doped mesoporous silica microspheres is 650.0 nm, and the average particle size of the thiol-modified strontium ion-doped mesoporous silica microspheres loaded with zoledronic acid is 664.9 nm. Compared with the average particle size of the thiol-modified strontium ion-doped mesoporous silica microspheres, the size of the drug-loaded microspheres does not change significantly, and the original structure of the thiol-modified strontium ion-doped mesoporous silica microspheres is maintained.

[0053] Modulus-vibration scanning test was performed on the composite gels loaded with strontium ions / zoledronic acid obtained in Examples 1-3 and the composite gel of Comparative Example 1, and the results are shown in Figure 6 As can be seen from the figure, the addition of zoledronic acid did not change the storage modulus of the composite gel, but the incorporation of nanoparticles and modified nanoparticles relatively greatly improved the storage modulus of the HSCG@MSN / Sr / ZA and HSCG@MSN / Sr composite gels.

[0054] Compression strength stress-strain curve test was performed on the composite gels loaded with strontium ions / zoledronic acid obtained in Examples 1-3 and the composite gel of Comparative Example 1, and the results are shown in Figure 7 As can be seen from the figure, the addition of zoledronic acid did not change the compression modulus of the composite gel, but the incorporation of nanoparticles and modified nanoparticles relatively greatly improved the compression modulus of the HSCG@MSN / Sr / ZA and HSCG@MSN / Sr composite gels, which was almost doubled compared with the pure gel group.

[0055] The cell proliferation activity of the composite gels of Examples 1-3 and Comparative Example 1 was evaluated by in vitro culture experiments of rat bone marrow mesenchymal stem cells (BMSC, Beijing Weitong Lihua Experimental Animal Technology Co., Ltd.). The Cell Counting Kit was used to detect the proliferation of cells in the composite gels, and the specific operation method was as follows: the sterilized sample was placed in a 48-well culture plate, and 1×10 4 cells / mL cell suspension was added to each well; the cell culture plate was placed in a cell culture incubator with 5% CO2 saturated humidity at 37°C, and the culture medium was changed every 2-3 days; after 1, 4 and 7 days of cell culture, the original culture medium was removed, 200-400 μL of new culture medium containing 10% CKK-8 solution was added, and the culture plate was placed in the incubator for 1-4 h; 100 μL of culture medium was taken from each well and placed in a 96-well plate; the absorbance value of each well at 450 nm wavelength was measured by a microplate reader (iMark, Bio-Rad, USA); and the results are shown in Figure 8 As can be seen from the figure, the cell proliferation of the HSCG@MSN / Sr composite gel group increased relative to the pure composite gel group due to the addition of strontium ion nanoparticles; and the cell activity and proliferation of the HSCG@MSN / Sr / ZA group were the best among the four composite gel groups due to the loading of zoledronic acid.

[0056] The in vitro blood vessel forming experiment of human umbilical vein endothelial cells (HUVEC, Cell Resource Center of Institute of Basic Medicine, Chinese Academy of Medical Sciences) was used to evaluate the blood vessel forming ability of the composite gel of examples 1-3 and comparative example 1. The Matrigel was used to test the blood vessel forming ability of various materials. The specific operation method is as follows: the sterilized sample was placed in a 48-well plate, and 1 mL of 3% serum-containing DMEM medium was added to each sample well according to the proportion of material surface area / culture medium = 1.25 cm 2 / mL, and incubated in an incubator for 24 h. The culture medium was collected as the sample leaching liquid. The Matrigel was uniformly coated in a 24-well plate at 4°C, and the well plate was placed in an incubator for 40 min. The sample leaching liquid was used to prepare a cell suspension at a density of 6x10 4 cell / mL, 500 μL of the cell suspension was added to the sample well coated with Matrigel, and the well plate was incubated in an incubator. After 6 h, the observation was performed with a microscope, and the images of 6 regions were randomly collected for data statistics in each group. The results are shown in the comparison chart of Figure 9 It can be seen that compared with the blood vessel forming ability of the endothelial cells cultured in the leaching liquid of the pure gel group, the number of blood vessels formed by the composite gel group loaded with zoledronic acid (HSCG@ZA) increased. The number of blood vessel nodes formed by HSCG@MSN / Sr composite gel was more due to the addition of strontium ion nanoparticles. The number of blood vessels formed by HSCG@MSN / Sr / ZA composite gel was more dense and continuous compared with HSCG@MSN / Sr composite gel due to the loading of zoledronic acid, and the blood vessel forming ability of the endothelial cells was improved.

[0057] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a strontium ion / zoledronic acid loaded composite gel, characterized by, The method comprises the following steps: 1g of sodium hyaluronate is dissolved in 100mL of deionized water to obtain a sodium hyaluronate solution, 283mg of solid cysteamine hydrochloride is added to obtain a thiol-modified sodium hyaluronate; 1g of carboxymethyl chitosan is dissolved in 100mL of deionized water to obtain a carboxymethyl chitosan solution, 1mL of liquid glycidyl methacrylate is added to obtain a double bond-modified carboxymethyl chitosan; 0.728g of cetyltrimethylammonium bromide and 2mL of ammonia water are dissolved in 100mL of deionized water to obtain a mixed solution, 4.167g of tetraethyl orthosilicate and 0.34g of strontium chloride hexahydrate are added to obtain mesoporous silica microspheres doped with strontium ions; 150mg of mesoporous silica microspheres doped with strontium ions are dispersed in 30mL of toluene solution, 0.2mL of 3-mercaptopropyl trimethoxysilane is added to obtain thiolated mesoporous silica microspheres doped with strontium ions; 500mg of thiolated mesoporous silica microspheres doped with strontium ions are dispersed in 200mL of deionized water, 200mg of solid zoledronic acid is added to obtain zoledronic acid-loaded thiolated mesoporous silica microspheres doped with strontium ions; The thiol-modified sodium hyaluronate and the double bond-modified carboxymethyl chitosan are respectively dissolved in deionized water to obtain precursor solutions A and B; precursor solutions A, B and the zoledronic acid-loaded thiolated mesoporous silica microspheres doped with strontium ions are thoroughly stirred and mixed, a photoinitiator is added, and irradiation is performed under ultraviolet light to form a strontium ion / zoledronic acid-loaded composite gel; the volume ratio of the precursor solution A to the precursor solution B is 1:2-4, the concentration of the zoledronic acid-loaded thiolated mesoporous silica microspheres doped with strontium ions is 0.1-0.5% w / v, and the concentration of the photoinitiator is 0.45-0.55% w / v.

2. The production method according to claim 1, characterized by, The step of dissolving sodium hyaluronate in deionized water to obtain a sodium hyaluronate solution and adding solid cysteamine hydrochloride to obtain a thiol-modified sodium hyaluronate specifically comprises: Sodium hyaluronate with a molecular weight of 1.0-1.8MDa is dissolved in deionized water and magnetically stirred until completely dissolved to obtain a sodium hyaluronate solution, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide are sequentially added to the solution and magnetically stirred until completely dissolved; cysteamine hydrochloride is added to the obtained mixed solution and magnetically stirred; the obtained mixed solution is dialyzed and freeze-dried to obtain a thiol-modified sodium hyaluronate.

3. The preparation method according to claim 1, characterized in that, The step of dissolving carboxymethyl chitosan in deionized water to obtain a carboxymethyl chitosan solution and adding liquid glycidyl methacrylate to obtain a double bond-modified carboxymethyl chitosan specifically comprises: Carboxymethyl chitosan is dissolved in deionized water and magnetically stirred until completely dissolved to obtain a carboxymethyl chitosan solution; glycidyl methacrylate is added to the obtained solution and magnetically stirred until uniformly mixed; the obtained mixed solution is dialyzed and freeze-dried to obtain a double bond-modified carboxymethyl chitosan.

4. The method of claim 1, wherein, The step of dissolving cetyltrimethylammonium bromide and ammonia water in deionized water to obtain a mixed solution, adding tetraethyl orthosilicate and strontium chloride hexahydrate to obtain mesoporous silica microspheres doped with strontium ions, specifically comprises the following steps: Cetyltrimethylammonium bromide and ammonia water are sequentially added to deionized water, and magnetic stirring is performed until complete dissolution to obtain a mixed solution; Tetraethyl orthosilicate and strontium chloride hexahydrate are sequentially added to the mixed solution, and magnetic stirring is performed until the mixture is uniformly mixed; the organic solvent is removed, centrifuged, and then washed with ethanol and deionized water alternately, and the nanoparticles are collected by centrifugation and vacuum dried; the obtained product is then placed in a tubular heating furnace for heating and calcination to remove excess cetyltrimethylammonium bromide, thereby obtaining mesoporous silica microspheres doped with strontium ions.

5. The preparation method according to claim 1, characterized in that, The step of dispersing the mesoporous silica microspheres doped with strontium ions into a toluene solution and adding 3-mercaptopropyltrimethoxysilane to obtain thiolated mesoporous silica microspheres doped with strontium ions, specifically comprises the following steps: The mesoporous silica microspheres doped with strontium ions are activated; the activated mesoporous silica microspheres doped with strontium ions are dispersed in toluene, magnetic stirring is performed until the particles are uniformly distributed, 3-mercaptopropyltrimethoxysilane is added, and condensation reflux is performed; the organic solvent is removed, centrifuged, and then washed with ethanol and deionized water alternately, and the nanoparticles are collected by centrifugation and vacuum dried to obtain thiolated mesoporous silica microspheres doped with strontium ions.

6. The method of claim 1, wherein, The step of dispersing the thiolated mesoporous silica microspheres doped with strontium ions into deionized water and adding solid zoledronic acid to obtain zoledronic acid-loaded thiolated mesoporous silica microspheres doped with strontium ions, specifically comprises the following steps: The thiolated mesoporous silica microspheres doped with strontium ions are dispersed in deionized water, and magnetic stirring is performed until the particles are uniformly distributed; zoledronic acid is added, and magnetic stirring is performed until complete dissolution; the solution is removed, centrifuged, and then washed with water and ethanol alternately, and the nanoparticles are collected by centrifugation and freeze-dried to obtain zoledronic acid-loaded thiolated mesoporous silica microspheres doped with strontium ions.

7. A strontium ion / zoledronic acid loaded composite gel, characterized in that, It is prepared by the preparation method of any one of claims 1-6.

8. Use of the strontium ion / zoledronic acid-loaded composite gel of claim 7 in the preparation of a bone defect repair material.

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