Injectable hydrogel for treating osteosarcoma

Abstract

The invention relates to injectable hydrogel for treating osteosarcoma, which is characterized in that a hydrogel matrix is formed by catechol modified gelatin GelHCA and phenylboronic acid modified glucan DEX-PBA, and is loaded with platinum-strontium deposited EGCG (epigallocatechin gallate) nanoparticles Sr (at) Pt (at) EGCG. According to the hydrogel, a dynamic covalent network is formed by catechol modified gelatin and phenylboronic acid modified glucan, a photothermal effect is achieved by adding the Sr-Pt-EGCG nanoparticles, the Pt nanoparticles can continuously generate ROS under the photothermal effect, meanwhile, EGCG also contains antioxidant components, the free radical scavenging and antibacterial capacity is remarkably improved, and the hydrogel has a good application prospect. In addition, by promoting differentiation and proliferation of osteoblasts, strontium ions can significantly improve the regeneration capacity of bone tissues and help repair bone defects. The hydrogel disclosed by the invention integrates four functions of photo-thermal therapy, immunotherapy, antibacterial protection and bone tissue regeneration, and forms an overall scheme of collaborative therapy.

Description

Technical Field

[0001] The invention belongs to the field of biomedical engineering materials, and in particular relates to an injectable hydrogel for treating osteosarcoma based on photothermal immunotherapy and antibacterial protection. Background Art

[0002] Osteosarcoma is the most common malignant bone tumor in children and adolescents. Current standard treatments include surgical resection, neoadjuvant chemotherapy, radiotherapy, and immunotherapy, but have encountered obstacles in completely eradicating the tumor and optimal bone tissue regeneration. Due to the complex anatomical structure of bone tissue, complete resection of osteosarcoma remains challenging, which often increases the risk of postoperative recurrence and metastasis. In addition, large-area surgical resection may result in unhealed bone defects or require amputation, seriously affecting the patient's quality of life, especially in pediatric cases. The current 3-year and 5-year event-free survival rates are 59% and 54%, respectively, highlighting the urgent need to improve prognosis and long-term bone health. However, there is indeed a contradiction between the elimination of residual osteosarcoma cells and bone repair. Although effective elimination of residual tumor cells after surgical resection is crucial to prevent recurrence and metastasis, the treatments used (such as chemotherapy and radiotherapy) can also have an adverse effect on bone regeneration. These therapies are known to destroy the regenerative microenvironment of bone, disrupt the proliferation and differentiation of osteocytes, and impair the natural healing and regeneration of bone tissue. In addition, the risk of infection in the postoperative wound further increases the complexity of treatment, not only affecting bone regeneration, but also exacerbating the risk of tumor recurrence. Therefore, achieving a balance between eliminating cancer cells, preventing postoperative infection, and promoting bone regeneration requires careful consideration and innovative approaches.

[0003] In recent years, innovative therapies based on nanotechnology and responsive materials have gradually become a research hotspot. In particular, photothermal therapy, with its non-invasiveness, local precision and high efficiency, has shown potential for application in the treatment of osteosarcoma. Photothermal therapy uses photothermal converters to generate local high temperatures under near-infrared light irradiation, selectively killing tumor cells while avoiding damage to surrounding healthy tissues. However, single photothermal therapy is difficult to eradicate tumor cells and cannot avoid recurrence. For this reason, immunotherapy, as a means of activating the patient's own immune system and suppressing tumors for a long time, is gradually being combined with photothermal therapy to exert a synergistic effect. However, how to achieve the organic combination of photothermal therapy and immunotherapy, while achieving controlled release of drugs, is an important problem in current research.

[0004] In addition to precise tumor killing, bone tissue repair after osteosarcoma treatment is also crucial. If the bone defect formed after surgical resection is not repaired in time, the patient's functional recovery will be greatly reduced. Although existing bone filling materials can promote bone regeneration to a certain extent, their biocompatibility is poor and the degradation rate is uncontrollable, making it difficult to meet clinical needs. Therefore, the development of multifunctional materials that can simultaneously promote bone regeneration and tumor treatment has become a research focus.

[0005] In this context, the emergence of responsive hydrogels provides new possibilities for multifunctional treatment strategies. Responsive materials can achieve precise drug release and enhance therapeutic effects according to external stimuli (such as pH, temperature, redox state). Targeting the special microenvironment of osteosarcoma (such as high oxidative stress, acidic environment, etc.), responsive hydrogels can play a therapeutic role at the right time and location, thereby effectively solving the limitations of current treatment options. Summary of the invention

[0006] In this context, the present invention provides an injectable hydrogel for the treatment of osteosarcoma, which can simultaneously achieve photothermal immunotherapy of osteosarcoma and bone defect repair.

[0007] The technical scheme of the present invention is as follows: The present invention provides an injectable hydrogel for treating osteosarcoma, wherein the hydrogel matrix is ​​formed by catechol-modified gelatin GelHCA and phenylboronic acid-modified dextran DEX-PBA, and is loaded with platinum-strontium deposited EGCG nanoparticles Sr@Pt@EGCG.

[0008] Catechol-modified gelatin and phenylboronic acid-modified dextran form a dynamic covalent network, which makes the hydrogel have good biocompatibility, self-healing and injectability. Sr@Pt@EGCG nanoparticles can produce photothermal effect through near-infrared light irradiation. Pt nanoparticles can continuously produce ROS under the action of photothermal. At the same time, EGCG also has antioxidant components, which can remove excessive ROS and have a lasting antibacterial effect. Strontium ions can significantly enhance the regeneration ability of bone tissue and help repair bone defects by promoting the differentiation and proliferation of osteoblasts.

[0009] Preferably, in terms of mass ratio, GelHCA:DEX-PBA:Sr@Pt@EGCG=10:5:2.

[0010] Preferably, the hydrogel is prepared by dissolving GelHCA in PBS and adjusting the pH value to 7.5, dispersing Sr@Pt@EGCG nanoparticles therein to obtain a GelHCA / Sr@Pt@EGCG solution; dissolving DEX-PBA in PBS to obtain a DEX-PBA solution; and finally vortex mixing the GelHCA / Sr@Pt@EGCG solution and the DEX-PBA solution.

[0011] Preferably, in the GelHCA / Sr@Pt@EGCG solution, the concentration of GelHCA is 10 w / v%, the concentration of Sr@Pt@EGCG nanoparticles is 2 mg / mL, and in the DEX-PBA solution, the concentration of DEX-PBA is 5% w / v.

[0012] In some embodiments, the catechol-modified gelatin used in the hydrogel of the present invention is prepared by dissolving EDC and NHS in MES buffer, and then adding them dropwise to MES buffer containing gelatin and catechol at room temperature under nitrogen protection to undergo a coupling reaction.

[0013] Preferably, the gelatin:catechol:EDC:NHS=1-2g:0.5-1.5g:0.8-1.5g:0.5-0.8g, and the reaction time is 12-36h. In a preferred embodiment, gelatin:catechol:EDC:NHS=1.2g:1g:1g:0.6g, and the reaction time is 24h.

[0014] In some embodiments, the phenylboronic acid-modified dextran used in the hydrogel of the present invention is prepared by dissolving phenylboronic acid in dichloromethane, adding carbonyldiimidazole for activation, then diluting with ethyl acetate, washing, drying, and concentrating to obtain carbonyldiimidazole-activated phenylboronic acid, and then adding 4-dimethylaminopyridine to the dextran and carbonyldiimidazole-activated phenylboronic acid in anhydrous DMSO, and mixing and stirring overnight to obtain the resultant.

[0015] Preferably, the phenylboronic acid: carbonyldiimidazole: dextran: 4-dimethylaminopyridine = 0.15-0.5g: 0.2g-0.6g: 60mg-120mg: 100mg-200mg, and the reaction time is 12h-24h. In a preferred embodiment, phenylboronic acid: carbonyldiimidazole: dextran: 4-dimethylaminopyridine = 0.339g: 0.469g: 90mg: 150mg, and the reaction time is 24h.

[0016] In some embodiments, the platinum-strontium deposited EGCG (Sr@Pt@EGCG) nanoparticles used in the hydrogel of the present invention are prepared by dispersing EGCG nanoparticles in double distilled water, then adding K2PtCl4 and SrCl2, stirring the mixed solution and heating it in an oil bath, and after reaching the desired reaction temperature, adding NaBH4 and continuing heating for 30 minutes, and then centrifuging and washing to obtain Sr@Pt@EGCG nanoparticles.

[0017] Preferably, EGCG: K2PtCl4: SrCl2: NaBH4 = 3mg-10mg: 2.5-7.5mg: 1.5-5.5mg: 1.5-5.5mg, the reaction temperature is 50°C-110°C, and the centrifugal speed is 8000-12000rpm. In a preferred embodiment, EGCG: K2PtCl4: SrCl2: NaBH4 = 7mg: 5mg: 3.5mg: 3.5mg, the reaction temperature is 80°C, and the centrifugal speed is 10000rpm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. Multifunctional integration: tumor removal and bone regeneration are carried out simultaneously.

[0020] The hydrogel of the present invention integrates four functions: photothermal therapy, immunotherapy, antibacterial protection, and bone tissue regeneration, forming an overall solution for synergistic treatment. This multifunctional integration can not only kill tumor cells locally and accurately, but also promote the repair of bone defects at the same time, meeting the dual needs of osteosarcoma treatment and bone regeneration. Compared with the single treatment method in the prior art, the present invention greatly improves the comprehensiveness and efficiency of the treatment.

[0021] 2. Precision tumor removal: combining photothermal and immunotherapy.

[0022] The Sr@Pt@EGCG metal polyphenol complex in the hydrogel produces a photothermal effect through near-infrared light irradiation, and local temperature rises to selectively kill tumor cells. At the same time, the photothermal effect can release tumor antigens, activate the patient's immune system, effectively eliminate residual tumor cells, and reduce the risk of recurrence. Compared with existing photothermal therapy, this invention combines the enhancement of immune response to make tumor removal more thorough.

[0023] 3. Reactive oxygen species (ROS) regulation: precise regulation of the tumor microenvironment.

[0024] The hydrogel of the present invention has dual functions. It can not only generate reactive oxygen species (ROS) to kill tumor cells during photothermal therapy, but also remove excess ROS through antioxidant ingredients such as EGCG to maintain the health of normal tissues. This dynamic regulation of ROS avoids the side effects caused by excessive ROS in the prior art, while accurately destroying the tumor microenvironment, inhibiting tumor cell proliferation and recurrence, and improving the safety and effectiveness of treatment.

[0025] 3. Long-lasting antibacterial effect: protection against postoperative infection.

[0026] The platinum (Pt) nanoparticles introduced into the hydrogel can continuously generate ROS under the action of light and heat, have a significant antibacterial effect, and can effectively prevent the risk of infection after surgery. Compared with traditional antibacterial measures (such as local use of antibiotics), the present invention provides continuous antibacterial protection and reduces the occurrence of postoperative complications.

[0027] 4. Promote bone tissue regeneration: Strontium ions enhance the osteogenesis effect.

[0028] The strontium ions in the present invention significantly enhance the regenerative capacity of bone tissue by promoting the differentiation and proliferation of osteoblasts, and help repair bone defects. Compared with traditional bone filling materials in the prior art, the present invention has better biocompatibility and bone formation-promoting effects in bone regeneration, and can significantly shorten bone healing time.

[0029] 5. Excellent biocompatibility and injectability.

[0030] The catechol-modified gelatin and phenylboronic acid-modified dextran form a dynamic covalent network, which makes the hydrogel have good biocompatibility, self-healing and injectability. This design not only enables the hydrogel to be accurately implanted into the target site through minimally invasive means, but also improves the flexibility and adaptability of the material, avoids the adverse reactions caused by the uncontrollable hardness or degradation rate of existing materials, and greatly improves the safety and convenience of surgery.

[0031] The innovative design of the injectable hydrogel of the present invention realizes multifunctional integration, which not only achieves significant improvements in tumor clearance, immune activation, antibacterial protection and bone tissue regeneration, but also has excellent biocompatibility and minimally invasive surgical advantages, overcoming many limitations of the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the scanning electron microscopy image of the hydrogel;

[0033] Figure 2 The temperature rise of OGHG0 and OGHG2 at different laser powers (0.5, 1 and 2 W / cm2) is shown.

[0034] Figure 3 (AC) Examining the effect of OGHG2 hydrogel on O2 · -(A), ABTS(B) and DPPH(C) free radical scavenging ability;

[0035] Figure 4 The cytotoxicity of OGHG0 and OGHG2 hydrogels to MG63 cells;

[0036] Figure 5 Shown are the survival rates of Escherichia coli and Staphylococcus aureus after treatment in different experimental groups. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0038] Example 1: Preparation of hydrogel

[0039] A hydrogel is composed of Sr@Pt@EGCG nanoparticles, GelHCA and DEX-PBA. The preparation method thereof is as follows:

[0040] First, GelHCA was dissolved in PBS solution at 10% w / v to obtain a GelHCA solution, and the pH value was adjusted to 7.5 by 1 M NaOH. Subsequently, an appropriate amount of Sr@Pt@EGCG nanoparticles was dispersed into the GelHCA solution by ultrasound at a Sr@Pt@EGCG nanoparticle concentration of 2 mg / mL; a GelHCA / Sr@Pt@EGCG solution was obtained.

[0041] DEX-PBA was dissolved in PBS solution at a concentration of 5% w / v to obtain a DEX-PBA solution.

[0042] Then, the above GelHCA / Sr@Pt@EGCG solution and DEX-PBA solution were mixed by vortex in an equal volume ratio to prepare a hydrogel, which was recorded as OGHG2.

[0043] Comparative Example 1

[0044] A hydrogel, which differs from Example 1 in that no Sr@Pt@EGCG nanoparticles are added. A 10% w / v GelHCA solution and a 5% w / v DEX-PBA solution were directly mixed by vortexing in an equal volume ratio to prepare a hydrogel, which was recorded as OGHG0.

[0045] The preparation methods of phenylboronic acid dextran (PHB-DEX), catechol functionalized gelatin (GelHCA), and platinum strontium deposited EGCG (Sr@Pt@EGCG) nanoparticles used in the examples and comparative examples are as follows:

[0046] (1) Preparation of phenylboronic acid dextran (PHB-DEX)

[0047] APBA (0.339 g, 31.5 mmol) was dissolved in 46 mL CH2Cl2, CDI (0.469 g, 62.9 mmol) was added, stirred for 30 min, diluted with ethyl acetate (200 mL), washed with deionized water (3×10 mL), washed with physiological saline (1×10 mL), dried over MgSO4, and concentrated in vacuo to obtain pure white solid APBA-CDI.

[0048] DEX (molecular weight = 10500 g mol -1 , 90 mg, 0.0086 mmol) was dissolved in anhydrous DMSO (1.575 mL), and then 4-dimethylaminopyridine (DMAP) (149.3 mg, 1.22 mmol) was added, followed by CDI-activated APBA (364.6 mg, 1.11 mmol, 2.0 mol / L). The mixture was stirred overnight, and the modified DEX was precipitated in deionized water (35 mL). The product was isolated by centrifugation for 15 minutes, and the resulting precipitate was washed with deionized water (2×35 mL). Phenylboronic acid-modified dextran (PHB-DEX) nanoparticles were collected by lyophilization.

[0049] (2) Preparation of catechol-functionalized gelatin (GelHCA)

[0050] GelHCA is prepared by EDC / NHS coupling reaction. The specific steps are as follows: 1.2g Gelatin and 1g HCA are completely dissolved in 150ml MES buffer (0.1mol / L, pH 4.7), and heated to dissolve at 25°C. Then 1.052g EDC and 0.632g NHS are dissolved in 10ml MES buffer (0.1mol / L, pH 5.5), added dropwise to the above solution under N2 protection, and stirred at 25°C for 24h. The mixture is then dialyzed with acidic pure water (MWCO 3,500) for 72h to remove unreacted HCA or salt, and then dialyzed with pure water (MWCO 3,500) for 10h. Finally, the purified product is freeze-dried and stored at 2-8°C for use.

[0051] (3) Preparation of platinum-strontium deposited EGCG (Sr@Pt@EGCG) nanoparticles

[0052] Sr@Pt@EGCG nanoparticles were created by a one-step noble metal deposition technique. EGCG nanoparticles (3.5 mL, 3 mg / mL) were first mixed into 6.5 mL of double distilled water (DDW), followed by the addition of 3.5 mg of SrCl2 and 5 mg of K2PtCl4. The mixed solution was gently stirred and heated to 80 °C in an oil bath. After reaching the desired temperature, 3.5 mg of NaBH4 was added and heating was continued for 30 min. The final product was then isolated using centrifugation at 10 000 rpm for 5 min and then washed three times with DDW. The final Sr@Pt@EGCG nanoparticles were resuspended in DDW for further applications.

[0053] Performance test of hydrogel:

[0054] 1. Morphology observation

[0055] like Figure 1 As shown, the morphology of the hydrogel obtained in Example 1 was observed by scanning electron microscopy. The hydrogel exhibited a porous cross-linked network structure.

[0056] 2. Photothermal properties of hydrogels

[0057] The photothermal properties of OGHG hydrogels were evaluated by experiments using NIR lasers. To investigate the photothermal effects of 808 nm laser light, different NIR laser powers (2.0, 1.0, and 0.5 W / cm 2 ) affects the photothermal efficiency of the material. The temperature changes of the material were closely tracked using a FLIR thermal imaging camera. The results are shown in Figure 2 As shown, the photothermal activity of the OGHG2 hydrogel of Example 1 was evaluated by 808 nm NIR laser, and the OGHG0 hydrogel of Comparative Example 1 was used as a control. The temperature of the OGHG0 hydrogel did not change significantly after 10 min of near-infrared light irradiation, while the temperature of the hydrogels with 2 mg / mL of Sr@Pt@EGCG increased rapidly, and the temperature continued to increase with the increase of photothermal power. When the OGHG2 power exceeded 1 W / cm 2 When the temperature of the gel is higher than 50 °C, it indicates that the OGHG2 hydrogel has significant photothermal activity.

[0058] 3. Reactive oxygen species (ROS) scavenging ability

[0059] The scavenging efficiency of the OGHG2 hydrogel of Example 1 on superoxide radicals (O2·-) was determined by the inhibition rate of nitro blue tetrazolium (NBT). A reaction mixture was prepared in a PBS solution, containing NBT (336 μM), nicotinamide adenine dinucleotide (936 μM), phenazine methyl sulfate (120 μM) and the prepared materials. After taking out the test sample, the mixture was maintained at 37°C for 6 minutes. Next, the absorbance of the sample at 560 nm was recorded. The scavenging ability of each sample on O2·- was calculated using the following formula: Inhibition rate (%) = (1-At / Ac) × 100%. Among them, Ac represents the absorbance of the blank control group, and At represents the absorbance of the sample of the OGHG2 hydrogel. The results are as shown in the figure. Figure 3 (A) shown.

[0060] In addition, the overall antioxidant capacity of the OGHG2 hydrogel of Example 1 was evaluated by the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. In a generalized procedure, 100 mg of hydrogel containing pt@EGCG nanoparticles was immersed in 1.0 ml of culture medium for 30 minutes. The extracts of these hydrogels were subjected to the total antioxidant capacity assay according to the instructions provided by the kit manufacturer. The subsequent steps involved measuring and comparing the absorbance of the solutions at 734 nm. The results are shown in Figure 2. Figure 3 (B) shown.

[0061] In addition, the antioxidant capacity of the OGHG2 hydrogel of Example 1 was evaluated by performing a DPPH free radical scavenging test, which measures its ability to neutralize free radicals. DPPH was mixed with ethanol (0.1 mM) into a new solution for testing. Subsequently, the sample was immersed in the DPPH solution and stored in a dark environment at 37°C for a period of time. Then, the absorbance of the reaction mixture was measured at a wavelength of 517 nm. The DPPH scavenging ability percentage was determined by the following formula: Inhibition rate (%) = (1-Aa / Ab) × 100%. In this formula, Ab represents the initial absorbance of the DPPH solution, and Aa represents the absorbance of DPPH after mixing with the sample to be tested for a period of time. The results are shown in Figure 2. Figure 3 (C) shown.

[0062] It can be seen that the free radical scavenging ability of the OGHG2 hydrogel of Example 1 is significantly higher than that of the OGHG0 of Comparative Example 1.

[0063] 4. Cytotoxicity

[0064] The method of detecting cell activity using CCK-8 was used to evaluate the toxic effects of OGHG0 in Comparative Example 1 or OGHG2 in Example 1 on human osteosarcoma MG63. The specific steps are as follows: First, human osteosarcoma MG63 was inoculated in a 96-well plate at a density of 5000 cells / well, and then placed in a carbon dioxide incubator to culture overnight. Subsequently, the original culture medium was aspirated and replaced with a fresh complete culture medium extract containing OGHG0 or OGHG2, with 5 parallels for each concentration. Then, the cells were cultured in an incubator for 24, 48h and 72h. After culture, the cells were washed once with PBS and 100 μL of fresh culture medium (containing 10% CCK-8) was added to each well. The cells were placed in an incubator and incubated for a period of time. Finally, an ELISA reader was used to detect and record the absorbance at a wavelength of 450 nm. The cell survival rate was calculated using the following formula: cell survival rate (%) = (absorbance of the experimental group - absorbance of the blank group) / (absorbance of the negative control group - absorbance of the blank group) × 100%.

[0065] The results are as follows Figure 4 As shown in the data, the cell survival rate of OGHG0 or OGHG2 was very high at different time periods, and neither of them produced any cytotoxicity to rat fibroblast RS1. Therefore, we believe that OGHG0 or OGHG2 materials have excellent biocompatibility and can be used as safe gel materials for the study of chronic wound treatment.

[0066] 5. Antibacterial

[0067] The excellent photothermal activity of the OGHG2 hydrogel of Example 1 inspired further evaluation of its antibacterial activity. The antibacterial activity of the prepared hydrogel against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was evaluated using agar disk diffusion test and surface contact test. E. coli and S. aureus were revived overnight in Luria-Bertani (LB) broth at 37°C. All hydrogel samples were sterilized by ultraviolet irradiation before testing.

[0068] The results are as follows Figure 5As shown, compared with the PBS control group, the OGHG0 hydrogel group can kill 17.3% of Staphylococcus aureus and 19.5% of Escherichia coli, which may be attributed to the presence of active amino groups in GelHCA. There was no significant difference in the antibacterial properties of OGHG0 hydrogels with or without NIR irradiation. However, OGHG2 hydrogels showed obvious antibacterial activity, with killing rates of 84.6% and 87.9% for Staphylococcus aureus and Escherichia coli, respectively; and combined with photothermal therapy, the antibacterial activity of the OGHG2 hydrogel + NIR group was further enhanced, and the synergistic antibacterial coefficients of photothermal and silver nanoparticles against Staphylococcus aureus and Escherichia coli reached 98.8% and 97.1%, respectively, proving that OGHG2 hydrogels have significant photothermal and platinum nanoparticle synergistic antibacterial properties. These results confirm that OGHG2 hydrogels have significant photothermal and silver nanoparticle synergistic antibacterial activity.

[0069] From the above, it can be seen that catechol-modified gelatin and phenylboronic acid-modified dextran can form a dynamic covalent network, which makes the hydrogel have good biocompatibility, self-healing and injectability. By introducing Sr@Pt@EGCG nanoparticles and producing a photothermal effect through near-infrared light irradiation, the free radical scavenging and antibacterial ability of the gel can be significantly improved. In addition, strontium ions significantly improve the regeneration ability of bone tissue and help repair bone defects by promoting the differentiation and proliferation of osteoblasts. The hydrogel of the present invention integrates four major functions: photothermal therapy, immunotherapy, antibacterial protection, and bone tissue regeneration, forming an overall solution for synergistic treatment.

[0070] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An injectable hydrogel for treating osteosarcoma, characterized in that: The hydrogel matrix is ​​formed by catechol-modified gelatin GelHCA and phenylboronic acid-modified dextran DEX-PBA, and is loaded with platinum-strontium deposited EGCG nanoparticles Sr@Pt@EGCG.

2. The injectable hydrogel for treating osteosarcoma according to claim 1, characterized in that: According to the mass ratio, GelHCA:DEX-PBA:Sr@Pt@EGCG=10:5:

2.

3. The injectable hydrogel for treating osteosarcoma according to claim 1, characterized in that: The hydrogel is prepared by dissolving GelHCA in PBS and adjusting the pH value to 7.5, dispersing Sr@Pt@EGCG nanoparticles therein to obtain a GelHCA / Sr@Pt@EGCG solution; dissolving DEX-PBA in PBS to obtain a DEX-PBA solution; and finally vortex mixing the GelHCA / Sr@Pt@EGCG solution and the DEX-PBA solution.

4. The injectable hydrogel for treating osteosarcoma according to claim 3, characterized in that: In the GelHCA / Sr@Pt@EGCG solution, the concentration of GelHCA is 10 w / v%, the concentration of Sr@Pt@EGCG nanoparticles is 2 mg / mL, and in the DEX-PBA solution, the concentration of DEX-PBA is 5% w / v.

5. The injectable hydrogel for treating osteosarcoma according to claim 1, characterized in that: The catechol-modified gelatin is prepared by dissolving EDC and NHS in MES buffer, then dropping them into MES buffer containing gelatin and catechol under nitrogen protection and room temperature to perform coupling reaction.

6. The injectable hydrogel for treating osteosarcoma according to claim 5, characterized in that: The gelatin: catechol: EDC: NHS = 1-2 g: 0.5-1.5 g: 0.8-1.5 g: 0.5-0.8 g, and the coupling reaction time is 12-36 h.

7. The injectable hydrogel for treating osteosarcoma according to claim 1, characterized in that: The phenylboronic acid-modified dextran is prepared by dissolving phenylboronic acid in dichloromethane, adding carbonyldiimidazole for activation, then diluting with ethyl acetate, washing, drying and concentrating to obtain carbonyldiimidazole-activated phenylboronic acid, and then adding 4-dimethylaminopyridine to the dextran and the carbonyldiimidazole-activated phenylboronic acid in anhydrous DMSO, and mixing and stirring overnight to obtain the resultant.

8. The injectable hydrogel for treating osteosarcoma according to claim 7, characterized in that: The phenylboric acid: carbonyldiimidazole: dextran: 4-dimethylaminopyridine = 0.15-0.5 g: 0.2-0.6 g: 60 mg-120 mg: 100 mg-200 mg, and the reaction time is 12 h-24 h.

9. The injectable hydrogel for treating osteosarcoma according to claim 1, characterized in that: The platinum-strontium deposited EGCG (Sr@Pt@EGCG) nanoparticles are prepared by dispersing EGCG nanoparticles in double distilled water, then adding K2PtCl4 and SrCl2, stirring the mixed solution and heating it in an oil bath, adding NaBH4 after reaching the desired reaction temperature, and continuing heating for 30 minutes, and then centrifuging and washing to obtain Sr@Pt@EGCG nanoparticles.

10. The injectable hydrogel for treating osteosarcoma according to claim 9, characterized in that: EGCG: K2PtCl4: SrCl2: NaBH4 = 3mg~10mg: 2.5~7.5mg: 1.5~5.5mg: 1.5~5.5mg, the reaction temperature is 50℃~110℃, and the centrifugal speed is 8000~12000rpm.

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