High mechanical performance particulate hydrogel, method of preparation and use thereof

Abstract

This invention relates to the field of composite material preparation technology, specifically to a high-mechanical-performance particulate hydrogel, its preparation method, and its applications. The method involves mixing gelatin nanoparticles, calcium carbonate nanoparticles, iron oxide nanoparticles, and sodium alginate solution under alkaline conditions, followed by the addition of gluconate-δ-lactone to prepare a high-mechanical-performance particulate hydrogel, abbreviated as Ca-Alg / MCG. This hydrogel system possesses properties suitable for catheter injection, vascular delivery, and intravascular hardening. The hydrogel can be delivered to the small blood vessels of tumors, and its mechanical properties gradually increase over time, further enhancing its embolizing effect in blood vessels. Simultaneously, the magnetic nanoparticles endow the hydrogel with magnetothermal responsiveness, allowing it to rapidly heat up under an alternating magnetic field, further killing tumor cells. Excellent embolizing effects have been observed in rabbit kidney embolization models and rabbit liver cancer embolization models.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to a high-mechanical-performance particulate hydrogel, its preparation method, and its application. Background Technology

[0002] Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver, accounting for 85% to 90% of all liver cancer cases. Globally, approximately 700,000 to 800,000 new cases are diagnosed annually. Transcatheter arterial embolization (TAE) is a mainstream treatment option. By selectively injecting an embolic agent into the tumor's feeding artery, it blocks the tumor's blood supply, inhibits tumor progression, and can significantly prolong the survival time of patients with intermediate to advanced HCC. Traditional embolic agents can be divided into solid embolic agents (polyvinyl alcohol microspheres and gelatin sponge particles) and liquid embolic agents (iodized oil). However, solid embolic agents are limited by size and cannot fill small, irregular blood vessels; moreover, they are prone to aggregation and clogging of catheters. In contrast, liquid embolic agents are more suitable for irregular, targeted blood vessels. Iodized oil has excellent flow properties, allowing it to rapidly enter the peripheral arteries of the tumor and exhibits good vascular conformation. However, its relatively low mechanical strength makes it susceptible to being cleared by blood flow, leading to potential recanalization within the tumor tissue. Therefore, enhancing the delivery characteristics of embolic agents in blood vessels while improving their mechanical properties is key to addressing these issues.

[0003] In recent years, shear-thinning hydrogels have attracted significant attention in the field of vascular embolization agents because they exhibit fluid-like behavior within catheters during injection and revert to their original gel state after stress removal. Particulate hydrogels, a type of shear-thinning hydrogel, utilize nanoparticles as assembly units, assembling from the bottom up into a three-dimensional network structure through non-covalent bonding. When the particulate hydrogel network is subjected to external stress or shear, its viscosity decreases sharply, exhibiting flow characteristics; however, once the external force is removed, it rapidly recovers its original viscosity, demonstrating structural self-healing capabilities. Due to its unique rheological properties, excellent biocompatibility, injectability, and catheter delivery capability, particulate hydrogels are considered highly promising new vascular embolization materials. However, this physically non-covalently formed particulate gel network has relatively weak mechanical properties and is unable to withstand large external loads. Consequently, after implantation into arteries, the particulate hydrogel structure is easily damaged under the shear and impact of high-speed blood flow, making it difficult to form stable and durable embolisms. While chemical crosslinking can effectively improve the mechanical properties and structural stability of particulate hydrogels, this technique often negatively impacts their injectability, making them unsuitable for delivery to the small blood vessels of tumors via catheters, thus failing to meet the needs of clinical embolization procedures. Furthermore, the potential biotoxicity of chemical crosslinking agents limits their application in clinical surgery. Therefore, developing colloidal gel hepatocellular carcinoma vascular embolization agents with excellent mechanical strength, injectability, delivery properties, and biocompatibility remains a challenge.

[0004] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of how to improve the mechanical properties of particulate hydrogels without affecting their injectability, and to provide a high-mechanical-performance particulate hydrogel, its preparation method and its application.

[0006] To achieve the above objectives, this invention discloses a method for preparing high-mechanical-performance particulate hydrogels, comprising the following steps:

[0007] S1, gelatin nanoparticles, iron oxide nanoparticles, calcium carbonate nanoparticles, and sodium alginate are mixed under alkaline conditions;

[0008] S2, add gluconate-δ-lactone powder to adjust pH, and obtain a particulate hydrogel with high mechanical properties.

[0009] The hydrolysis of glucono-δ-lactone causes a slow decrease in pH, resulting in a change in charge from negative to positive for gelatin nanoparticles, while iron oxide nanoparticles retain their negative charge, leading to electrostatic interactions between the two types of particles. Subsequently, calcium carbonate nanoparticles are acidified by hydrogen ions generated from the hydrolysis of glucono-δ-lactone, releasing calcium ions which crosslink with sodium alginate, further enhancing the mechanical properties of the particulate hydrogel formed by the aforementioned electrostatic interactions. Thus, a particulate hydrogel with high mechanical properties can be obtained.

[0010] In step S1, the preparation method of gelatin nanoparticles includes the following steps:

[0011] S111, gelatin is heated and dissolved in deionized water to obtain a gelatin solution, then acetone is added, and the mixture is allowed to stand at room temperature for 1 hour. The supernatant is removed, the precipitate is dissolved again in deionized water and freeze-dried to obtain freeze-dried high molecular weight gelatin.

[0012] S112, dissolve the freeze-dried gelatin obtained in step S111 in deionized water, add dilute hydrochloric acid to adjust the pH to 2.5, add acetone dropwise while stirring, then add glutaraldehyde solution to the gelatin dispersion at room temperature, stir in the dark for 16 hours, then add glycine aqueous solution to the gelatin dispersion, stir for 1 hour, filter, centrifuge and wash to obtain amphoteric gelatin nanoparticles.

[0013] In step S1, the method for preparing iron oxide nanoparticles includes the following steps:

[0014] S121, Add 1.08 g of ferric chloride hexahydrate to a mixed solution of 10 mL of ethylene glycol and 30 mL of diethylene glycol, and stir for 30 min;

[0015] S122, Take 0.1g of polyacrylic acid and add it to the mixed solution in step S121, and stir for 30min;

[0016] S123, add 6g of anhydrous sodium acetate to the mixed solution in step S122 and stir for 1 hour;

[0017] S124. Place the mixed solution from step S123 into a high-pressure reactor and react it at high temperature. Centrifuge and wash the resulting black product to obtain iron oxide nanoparticles.

[0018] In step S124, the reaction temperature is 200℃ and the reaction time is 12h.

[0019] In step S1, the method for preparing calcium carbonate nanoparticles includes the following steps:

[0020] S131, dissolve 150 mg of calcium chloride dihydrate in 100 mL of ethanol;

[0021] S132, Take 5g of ammonium bicarbonate powder and place it in a sealed container;

[0022] S133, the mixed solution from step S131 is placed in the sealed container from step S132, and then placed in an oven for reaction under vacuum. The white product obtained by centrifugation and washing is calcium carbonate nanoparticles.

[0023] In step 133, the reaction temperature is 40°C and the reaction time is 24 hours.

[0024] In step S1, gelatin nanoparticles, iron oxide nanoparticles, calcium carbonate nanoparticles, and sodium alginate are vortexed and mixed at pH≈11.

[0025] In step S2, the solid content of the high mechanical property particulate hydrogel obtained is 11.0 w / v% to 13.5 w / v.

[0026] This invention also discloses the application of high mechanical properties particulate hydrogels prepared by the above-mentioned preparation method in the preparation of interventional embolization agents for combined magnetothermal therapy of liver cancer.

[0027] This invention introduces sodium alginate and calcium carbonate nanoparticles into a particulate hydrogel system composed of gelatin nanoparticles and iron oxide nanoparticles. Under the slow hydrolysis environment of gluconate-δ-lactone, the mechanical properties are gradually enhanced, resulting in a high-mechanical-performance particulate hydrogel, abbreviated as Ca-Alg / MCG. Sodium alginate is a natural polyanionic polysaccharide molecule with a strong affinity for divalent ions (such as calcium ions). Divalent ions can bind to the α-L-guluronic acid of alginate molecules, forming ionic crosslinks. Calcium carbonate gradually dissociates, releasing calcium ions which chelate with sodium alginate, slowly enhancing the mechanical properties of the particulate hydrogel. The storage modulus of this particulate hydrogel increases to 11 times its original modulus after two hours. It exhibits excellent vascular embolization effects in rabbit kidney embolization and rabbit liver cancer embolization models. Furthermore, the magnetic nanoparticles generate heat in response to an alternating magnetic field, further killing tumor cells.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The hydrogel prepared by this invention is a three-dimensional hydrogel network formed by the controllable electrostatic assembly of building blocks, and then the natural polysaccharide sodium alginate is chelated with calcium ions to enhance the mechanical properties of the particulate hydrogel. It does not involve complex chemical cross-linking or toxic cross-linking agents. The raw materials and cross-linking methods have good biocompatibility, which is beneficial to clinical translation.

[0030] 2. The mechanically enhanced particulate hydrogel prepared by this invention possesses both injectability and enhanced mechanical properties. Particulate hydrogels typically have weak mechanical properties, limiting their application in arterial vessels. Common methods to improve the mechanical properties of hydrogels involve increasing their cross-linking degree using irreversible covalent bonds, but this reduces the injectability of the hydrogel. Therefore, the mechanically enhanced particulate hydrogel prepared by this invention exhibits good injectability in the initial stage of preparation, and its mechanical properties can be further improved over time.

[0031] 3. The high mechanical properties of the particulate hydrogel prepared by this invention have good magnetic field responsiveness and can be rapidly heated under an alternating magnetic field to further kill tumors, thereby achieving embolization combined with magnetothermal synergistic therapy. Attached Figure Description

[0032] Figure 1 Scanning electron microscope image (A) and hydrated particle size diagram (B) of gelatin nanoparticles;

[0033] Figure 2 Scanning electron microscope image (A) and hydrated particle size diagram (B) of iron oxide nanoparticles;

[0034] Figure 3 Scanning electron microscope image (A) and hydrated particle size diagram (B) of calcium carbonate nanoparticles;

[0035] Figure 4 Scanning electron microscope (SEM) images of the internal structure of MCG (A) and the internal structure of Ca-Alg / MCG (B);

[0036] Figure 5 Photos of MCG and Ca-Alg / MCG casting and demolding processes;

[0037] Figure 6 The deformation of MCG and Ca-Alg / MCG under external load;

[0038] Figure 7 For Ca0-Alg1 / MCG, Ca0-Alg / MCG, and Ca0-Alg2 / MCG, an injection force of 2.6F was applied.

[0039] Figure 8 The embolization pressures are Ca0-Alg1 / MCG, Ca0-Alg / MCG, and Ca0-Alg2 / MCG.

[0040] Figure 9 For MCG, Ca0-Alg / MCG, Ca 0.5 -Alg / MCG, Ca 1.0 -Alg / MCG, Ca 1.5 - Comparison of storage modulus of Alg / MCG before and after gelation;

[0041] Figure 10 For the on-the-fly preparation of CaO-Alg / MCG, Ca 0.5 -Alg / MCG, Ca 1.0 -Alg / MCG, Ca 1.5 -Shear thinning test of Alg / MCG;

[0042] Figure 11 For the on-the-fly preparation of CaO-Alg / MCG, Ca 0.5 -Alg / MCG, Ca 1.0 -Alg / MCG, Ca 1.5 -Alg / MCG catheter injection force;

[0043] Figure 12 Ca prepared on the spot 1.0 -Alg / MCG peak retention test;

[0044] Figure 13 For MCG, Ca 1.0 -Graph showing the modulus of Alg / MCG over time;

[0045] Figure 14 The relationship between the cumulative release of calcium ions and time;

[0046] Figure 15 For MCG, Ca 1.0 -Alg / MCG embolic pressure;

[0047] Figure 16 For Ca 1.0 - Digital subtraction angiography (DSA) and X-ray images of Alg / MCG in rabbit renal embolism;

[0048] Figure 17 Computed tomography (CT) images of the blank control group and 28 days after embolization;

[0049] Figure 18 Color Doppler ultrasound (CDU) images and contrast-enhanced ultrasound (CEUS) images were taken as a blank control group and 28 days after embolization.

[0050] Figure 19 Three-dimensional modeling images of the kidneys in the blank control group and 28 days after embolization;

[0051] Figure 20 Photographs of the kidneys in the blank control group and 28 days after embolization;

[0052] Figure 21 Images of kidney tissue stained with hematoxylin and eosin (H&E staining) on ​​day 0 and day 28 of embolization;

[0053] Figure 22 Images of kidney tissue stained with Prussian blue (PB staining) on ​​day 0 and day 28 of embolization;

[0054] Figure 23 For Ca 1.0 -Magnetic thermal heating effect of Alg / MCG in tumor models;

[0055] Figure 24 X-ray and DSA images of rabbits with liver cancer before and after tumor vascular embolization;

[0056] Figure 25 Photos of rabbits with liver cancer 14 days after treatment: untreated, treated with arterial embolization, and treated with arterial embolization combined with magnetothermal therapy.

[0057] Figure 26 H&E staining images of rabbits with hepatocellular carcinoma 14 days after untreated, treated with arterial embolization, and treated with arterial embolization combined with magnetothermal therapy;

[0058] Figure 27 PB staining images of rabbits with liver cancer 14 days after treatment, treatment with arterial embolization, and treatment with arterial embolization combined with magnetothermal therapy. Detailed Implementation

[0059] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0060] Example 1

[0061] 1. Preparation of gelatin nanoparticles, the steps are as follows:

[0062] Spherical gelatin nanoparticles were prepared by a two-step solvent removal method.

[0063] (1) Dissolve 25g of gelatin in 500mL of deionized water at 50℃. Then, add 500mL of acetone to the gelatin solution. After the mixture stands at room temperature for 1 hour, remove the supernatant, dissolve the gelatin precipitate again in deionized water at 50℃, and freeze-dry to obtain high molecular weight gelatin.

[0064] (2) Dissolve 3.75 g of high molecular weight gelatin in 75 mL of deionized water, and then add dilute hydrochloric acid to adjust the pH of the solution to 2.5. While stirring at 1000 rpm, add 225 mL of acetone dropwise to the gelatin solution at 10 mL / min using a syringe pump. After the reaction solution cools to room temperature, add 550 μL of glutaraldehyde solution (25 wt%), and stir at 600 rpm for 16 hours under light-protected conditions.

[0065] (3) Add 100 mL of 300 mM glycine aqueous solution to the gelatin dispersion prepared in step (2) to remove unreacted aldehyde groups. After stirring for 1 hour, filter the dispersion through a 100 μm sieve. Then, by centrifugation and washing, redisperse the precipitate in an acetone aqueous solution (volume ratio of acetone:water = 1:3) for later use.

[0066] 2. Preparation of iron oxide nanoparticles, the steps are as follows:

[0067] Ferric oxide nanoparticles were prepared by a solvothermal method.

[0068] (1) Dissolve 1.08 g of ferric chloride hexahydrate in a mixed solution of 10 mL of ethylene glycol and 30 mL of diethylene glycol, and stir for 30 minutes until completely dissolved. Then add 0.1 g of polyacrylic acid and stir for 30 minutes. Finally, add 6 g of anhydrous sodium acetate and stir for 1 hour.

[0069] (2) Transfer the mixed solution obtained in step (1) to a high-pressure reactor and react at 200°C for 12 hours.

[0070] (3) After the reaction is complete, centrifuge and wash the black product continuously for later use.

[0071] 3. Preparation of calcium carbonate nanoparticles, the steps are as follows:

[0072] Calcium carbonate nanoparticles were prepared by atmospheric diffusion method.

[0073] (1) Dissolve 150 mg of calcium chloride dihydrate in 100 mL of ethanol and place it in a sealed container.

[0074] (2) Place 5g of ammonium bicarbonate in a sealed container.

[0075] (3) Place the sealed container in an oven at 40°C and react under vacuum for 24 hours. After the reaction is complete, centrifuge and wash the white product for later use.

[0076] 4. Preparation of mechanically enhanced particulate hydrogels, the steps are as follows:

[0077] The prepared alkaline (pH≈11) gelatin nanoparticle dispersion, iron oxide nanoparticle dispersion, sodium alginate solution, and calcium carbonate nanoparticle dispersion were vortex-mixed until homogeneous, with final system concentrations of 8 w / v%, 2 w / v%, 2 w / v%, and 1 w / v, respectively. Then, 50 mg of GDL powder was added to adjust the pH of the system to induce gelation, thus obtaining a mechanically enhanced particulate hydrogel, Ca1. 1.0 -Alg / MCG.

[0078] Example 2

[0079] In this example, the calcium carbonate nanoparticle content was 0.5 w / v, the GDL addition was 32 mg, and other preparation conditions were the same as in Example 1, abbreviated as Ca 0.5 -Alg / MCG.

[0080] Example 3

[0081] In this example, the calcium carbonate nanoparticle content was 1.5 w / v, the GDL addition was 67 mg, and other preparation conditions were the same as in Example 1, abbreviated as Ca. 1.5 -Alg / MCG.

[0082] Example 4

[0083] In this embodiment, the content of calcium carbonate nanoparticles is 0, the content of sodium alginate is 2 w / v, the amount of GDL added is 14 mg, and other preparation conditions are the same as in Example 1, abbreviated as CaO-Alg / MCG.

[0084] Example 5

[0085] In this embodiment, the content of calcium carbonate nanoparticles is 0, the content of sodium alginate is 1 w / v, the amount of GDL added is 14 mg, and other preparation conditions are the same as in Example 1, abbreviated as Ca0-Alg1 / MCG.

[0086] Example 6

[0087] In this embodiment, the content of calcium carbonate nanoparticles is 0, the content of sodium alginate is 3 w / v, the amount of GDL added is 14 mg, and other preparation conditions are the same as in Example 1, abbreviated as CaO-Alg2 / MCG.

[0088] Comparative Example 1

[0089] The prepared alkaline (pH≈11) gelatin nanoparticle dispersion and iron oxide nanoparticle dispersion were vortexed and mixed evenly, with final system concentrations of 8 w / v% and 2 w / v%, respectively. Then, 14 mg of GDL powder was added to adjust the pH of the system to induce gelation, thus obtaining a high-mechanical-performance particulate hydrogel, abbreviated as MCG.

[0090] Figure 1 The images show scanning electron microscope (SEM) images and hydrated particle size distributions of gelatin nanoparticles. The gelatin nanoparticles exhibit a uniform and smooth surface and a particle size of approximately 240 nm. Figure 2 The images show scanning electron microscope (SEM) images and hydrated particle size distributions of iron oxide nanoparticles. The iron oxide appears as coarse, spherical particles with a diameter of approximately 130 nm. Figure 3 The image shows a scanning electron microscope (SEM) image and hydrated particle size diagram of calcium carbonate nanoparticles, with a particle size of approximately 110 nm.

[0091] Figure 4The internal structures of gelled particulate hydrogels (MCG) and high-mechanical-performance particulate hydrogels (Ca-Alg / MCG) were compared. The results showed that MCG is simply a three-dimensional network assembled from particles, while Ca-Alg / MCG exhibits a polymer network encapsulating nanoparticles. Figure 5 The shapes of particulate hydrogels (MCG) and high-mechanical-performance particulate hydrogels (Ca-Alg / MCG) after molding and demolding were compared. Compared to MCG, Ca-Alg / MCG exhibits a finer contour after demolding and can be picked up with tweezers, demonstrating superior mechanical properties. Figure 6 This demonstrates that Ca-Alg / MCG can resist external forces and is not easily deformed. It can return to its original shape after the external force is removed, and has stronger mechanical properties than MCG.

[0092] To clarify the effect of sodium alginate content on the mechanical properties of particulate hydrogels, different amounts of sodium alginate were added to the particulate hydrogel MCG. Figure 7 It is evident that when the sodium alginate content is 3 w / v%, the force required to inject the particulate hydrogel through a 2.6F catheter at an injection rate of 1 mL / min exceeds 50 N, making injection impossible. However, when the sodium alginate content is 1 w / v% and 2 w / v%, the injection force is less than 50 N, making injection through the catheter easier. Figure 8 The embolization pressure was tested at three different sodium alginate contents. When the sodium alginate content was 1 w / v%, the embolization pressure was lower than the physiological arterial pressure (16 kPa) in humans, while the embolization pressure of the other two hydrogels exceeded 16 kPa, indicating that they have a certain ability to resist blood shock.

[0093] Figure 9 The storage modulus of the hydrogels in Examples 1, 2, 3, 4, and Comparative Example 1 before and after gelation was compared. In Comparative Example 1, the MCG gelled due to electrostatic assembly, causing its storage modulus to increase from 192.2 ± 11.0 Pa to 312.4 ± 27.2 Pa. In Example 4, the storage modulus of CaO-Alg / MCG after gelation was 573.3 ± 15.6 Pa, which did not significantly affect the storage modulus of the MCG. The CaO-Alg / MCG in Example 1... 1.0 -Alg / MCG exhibited excellent mechanical properties, with the Pa increasing from 615.7±39.8 to 7284.5±164.2 before and after gelation. In Example 2, Ca... 0.5 The low storage modulus of Alg / MCG gelled material (3306.4 ± 56.9 Pa) is due to the low content of calcium carbonate nanoparticles, resulting in insufficient cross-linking. In Example 3, Ca... 1.5The storage modulus of Alg / MCG after gelation was 5376.7 ± 119.7 Pa. In this example, the calcium carbonate nanoparticle content was too high, and the excessive calcium ions unevenly chelated with sodium alginate, hindering the formation of symmetrical "eggbox" dimers and causing cross-linking between and within alginate molecules, ultimately reducing gel hardness. Therefore, the improvement in gel mechanical properties was most significant in Example 1.

[0094] Figure 10 The shear-thinning properties of the on-the-spot hydrogels of Examples 1, 2, 3, and 4 were tested, and their viscosity decreased with increasing shear rate. Figure 11 The catheter injectability of the on-the-fly prepared hydrogels of Examples 1, 2, 3, and 4 was tested. The injection forces through the 4F catheter were 12.4±0.3N, 12.2±0.1N, 14.8±0.3N, and 10.6±1.1N, respectively, and the injection forces through the 2.6F catheter were 27.8±0.7N, 26.8±0.8N, 31.2±0.9N, and 25.8±0.9N, respectively. The results indicate that the on-the-fly prepared hydrogels of Examples 1, 2, 3, and 4 all exhibit good catheter injectability.

[0095] Peak retention tests were performed to evaluate the viscosity change of the hydrogel during extrusion through a conduit. Figure 12 As shown, at the start of the extrusion process, the hydrogel is subjected to a low shear rate (0.01 s⁻¹). -1 Subsequently, as the hydrogel passed through the catheter, the shear rate increased to 1140 s. -1 Then, it drops sharply (0.01s) after the hydrogel leaves the catheter tip. -1 The results showed that the Ca prepared on-site in Example 1 1.0 -Alg / MCG not only exhibits shear-thinning behavior, but also recovers to its original viscosity under the aforementioned shear rate changes. Figure 13 The Ca prepared on-the-spot in Example 1 was tested. 1.0 The change in Alg / MCG modulus over time shows that its storage modulus begins to increase around 4 minutes and reaches a plateau around 80 minutes, indicating that the modulus change in Example 1 increases over time, while providing clinicians with sufficient surgical time. Figure 14 As shown, the cumulative release of calcium ions over time was tested. It can be seen that the release gradually increases over time, reaching about 90% at around 80 minutes, which indirectly confirms the modulus change characteristics of the hydrogel in Example 1 over time. Figure 15 This demonstrates the maximum pressure that the hydrogels in Comparative Example 1 and Example 1 can withstand. The embolization pressure of MCG is approximately 12.1 ± 1.6 kPa, while that of Ca... 1.0The embolization pressure of Alg / MCG increased from the initial 22.2±1.2 kPa to 69.9±6.0 kPa, confirming that the mechanical properties of Example 1 also improved over time.

[0096] The embolization effect of Example 1 was evaluated using a rabbit kidney embolism model. Figure 16 As shown, prior to embolization, DSA imaging revealed a clear outline of both kidneys and their vascular pathways. The hydrogel from Example 1 was prepared immediately and incorporated with iodixanol. It was injected into the right renal artery via a catheter. X-ray imaging showed that the hydrogel accumulated in the renal artery and small vessels. Post-embolization DSA imaging showed a clear outline of the left kidney, while the right renal vessels were not visualized, indicating complete embolization of the right kidney. Figure 17 As shown, CT imaging data 28 days after embolization showed a significant reduction in the volume of the right kidney. Figure 18 The images show CDU and CEUS images 28 days after embolization. The results indicate that the kidney volume decreased and there was no blood supply 28 days after embolization. Meanwhile... Figure 19 Three-dimensional modeling data showed that the right renal artery and kidney were not visible 28 days after embolization. Figure 20 The photograph shows the kidney 28 days after embolization, confirming right kidney atrophy and indicating that the hydrogel in Example 1 has a good embolization effect. Figure 21 As shown, H&E staining images of kidney tissue indicate that on day 28 after embolization, kidney tissue cell nuclei showed extensive deformation and apoptosis, and extensive tissue necrosis. Figure 22 PB staining of kidney tissue confirmed that the hydrogel's long-term retention in renal blood vessels can stably and effectively embolize the vessels.

[0097] Iron oxide nanoparticles possess excellent magnetic response properties. A tumor model was used to evaluate whether the magnetocaloric effect of high-mechanical-performance particulate hydrogels under an alternating magnetic field could kill tumor edge cells. An infrared camera was used to monitor the surface temperature of the tumor model, and a fiber optic temperature sensor was used to measure internal temperature changes. Figure 23 Under an electric field strength of 25 kA / m, the surface temperature of the tumor model reached 45°C after approximately 20 minutes, confirming that the hydrogel can kill tumor edge cells under an alternating magnetic field. The embolization and magnetothermal therapeutic effects of the hydrogel in Example 1 were verified using rabbits with liver cancer. Figure 24 As shown, the tumor location (green circle) and its feeding artery are visible before embolization. After embolization, the tumor location is no longer visible, confirming that the tumor vessels have been embolized. Figure 25Images of the livers 14 days after treatment are shown in the following figures: untreated group, transarterial embolization group, and transarterial embolization combined with magnetothermal therapy group. Results show that the tumor volume in the untreated group was significantly larger. After transarterial embolization, the tumor volume decreased, confirming that embolization can inhibit tumor progression. The tumor volume was smallest after transarterial embolization combined with magnetothermal therapy, indicating that magnetothermal therapy can further inhibit tumor growth on top of embolization treatment. Figure 26 H&E staining images of tumor tissue showed that, compared with the transarterial embolization group, the transarterial embolization combined with magnetothermal therapy group showed more tumor cell nuclear deformation and apoptosis, as well as large-area tissue necrosis, indicating that magnetothermal therapy can significantly improve the efficacy of embolization therapy. Figure 27 The images show PB staining of tumor tissue, indicating that the hydrogel can effectively occlude blood vessels. These experimental results demonstrate that the hydrogel in Example 1 exhibits a stable and long-lasting embolization effect in rabbit hepatocellular carcinoma tumor embolization, and can be combined with magnetothermal therapy to enhance efficacy.

[0098] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A method for preparing a high mechanically performing particulate hydrogel, characterized in that, The method comprises the following steps: S1, mixing gelatin nanoparticles, iron oxide nanoparticles, calcium carbonate nanoparticles and sodium alginate under alkaline conditions; S2, adding gluconic acid-delta-lactone powder to adjust the pH to obtain a high-mechanical-property particulate hydrogel; In the step S1, the preparation method of the gelatin nanoparticles comprises the following steps: S111, dissolving gelatin in deionized water to obtain a gelatin solution, then adding acetone, standing at room temperature for 1 h, removing the supernatant, dissolving the precipitate in deionized water again and freeze-drying to obtain freeze-dried high-molecular-weight gelatin; S112, dissolving the freeze-dried gelatin obtained in step S111 in deionized water, adding dilute hydrochloric acid to adjust the pH to 2.5, stirring and adding acetone drop by drop, then adding glutaraldehyde solution to the gelatin dispersion at room temperature, stirring in the dark for 16 h, then adding glycine aqueous solution to the gelatin dispersion, stirring for 1 h, and then filtering and centrifuging to wash to obtain amphoteric gelatin nanoparticles; In the step S1, the preparation method of the iron oxide nanoparticles comprises the following steps: S121, adding 1.08 g of iron chloride hexahydrate to a mixed solution of 10 mL of ethylene glycol and 30 mL of diethylene glycol, and stirring for 30 min; S122, taking 0.1 g of polyacrylic acid and adding it to the mixed solution of step S121, and stirring for 30 min; S123, taking 6 g of anhydrous sodium acetate and adding it to the mixed solution of step S122, and stirring for 1 h; S124, placing the mixed solution of step S123 in a high-pressure reaction kettle and reacting at high temperature, and then centrifuging and washing the obtained black product to obtain iron oxide nanoparticles; In the step S124, the reaction temperature is 200°C and the reaction time is 12 h.

2. The method of claim 1, wherein the high mechanically performance particulate hydrogel is prepared by the steps of: In the step S1, the preparation method of the calcium carbonate nanoparticles comprises the following steps: S131, taking 150 mg of calcium chloride dihydrate and dissolving it in 100 mL of ethanol; S132, taking 5 g of ammonium bicarbonate powder and placing it in a sealed container; S133, placing the mixed solution in step S131 in the sealed container in step S132, and then placing it in an oven and reacting under vacuum, and then centrifuging and washing the obtained white product to obtain calcium carbonate nanoparticles.

3. The method for preparing a high-mechanical-performance particulate hydrogel as described in claim 2, characterized in that, In the step S133, the reaction temperature is 40°C and the reaction time is 24 h.

4. The method for preparing a high-mechanical-performance particulate hydrogel as described in claim 1, characterized in that, In the step S1, the gelatin nanoparticles, iron oxide nanoparticles, calcium carbonate nanoparticles and sodium alginate are vortex mixed at pH≈11.

5. The method for preparing a high-mechanical-performance particulate hydrogel as described in claim 1, characterized in that, In the step S2, the solid content of the obtained high-mechanical-property particulate hydrogel is 11.0 w / v% to 13.5 w / v%.

6. A high-mechanical-property particulate hydrogel prepared by the preparation method of any one of claims 1 to 5.

7. Use of the high-mechanical-property particulate hydrogel of claim 6 in the preparation of an interventional embolic agent for combined magnetic and thermal treatment of liver cancer.

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