Hydrogel as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biological medicine, and discloses hydrogel and a preparation method and application thereof.The preparation method comprises the steps that under the condition of ice bath, polydopamine modified Fe3O4 nanoparticles, cellulose nanofibers and a catalyst are subjected to a reaction, and the hydrogel is obtained; the catalyst is a mixture of N-(3-dimethylaminopropyl)-N '-ethyl carbodiimide hydrochloride and N-hydroxy succinimide. The method is characterized in that the catalyst is a mixture of N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride. The invention aims to develop the spongy magnetic thermal therapy hydrogel with the hollow tube structure, and magnetic thermal therapy, chemical power therapy and chemotherapy are combined, so that the treatment effect is improved, and the side effect is reduced. The hydrogel is prepared from the Fe3O4 (at) PDANPs nanoparticles and carboxylated cellulose nanofibers through a covalent cross-linking method, and the hydrogel which is rapid in expansion and high in compressive strength and toughness is obtained. Growth of colorectal cancer tumors is remarkably inhibited through the synergistic effect of magnetic heat, chemotherapy and chemical kinetics treatment at the tumor site.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedicine, and specifically relates to a hydrogel and a preparation method and application thereof. Background Art

[0002] Colorectal cancer is one of the most common malignant tumors in the gastrointestinal tract. The most thorough treatment method available is surgery. For patients with colorectal cancer whose tumors are close to the anus, surgical resection will make organ preservation difficult, thus seriously affecting the patient's normal life. Therefore, effective preoperative treatment, reducing the size of the tumor to increase the possibility of preserving the anus and completely removing the tumor, is the key to the treatment of colorectal cancer.

[0003] Drug delivery systems, abbreviated as DDSs, are based on biomaterials and can achieve targeted drug delivery to tumor sites, which has become a core area of ​​current research. A variety of chemotherapy drug delivery systems based on nanoparticles and hydrogels have been successfully developed and applied to the treatment of colorectal cancer. For example, Wu et al. successfully prepared a solid lipid nanoparticle delivery system with excellent photosensitization effect, which can effectively destroy cancer cells. Reference: Wu, B.; Gan, Z.; Tao, S.; Wang, Q.; Song, Y.; Zhong, H.; Hu, F. High-efficiency photosensitizer encapsulated in dextran-cholesterol carrier for photodynamic killing of cancer cells. Molecules 2023, 28, 4404. https: / / doi.org / 10.3390 / molecules28114404. Experiments have shown that the particles can produce more reactive oxygen species under light conditions, thereby achieving excellent killing effects on cancer cells. In addition, the particles are selective and can kill cancer cells in a targeted manner without damaging normal cells. Hu et al. described the preparation of a new type of hydrogel and its application in anticancer drug delivery. Reference: Hu Nannan, Yang Fuxu, Mu Yeteng, Guo Chong, Xue Han, Fan Yuxin, Guo Fenglin, Guan Xingang. Preparation of oxaliplatin-loaded elastin polypeptide hydrogel and its killing effect on mouse colon cancer CT26 cells[J]. Journal of Jilin University (Medical Edition), 2023, 49(1): 94-100. This hydrogel is composed of elastin polypeptide and oxaliplatin, showing good drug release performance and anticancer efficacy. The experimental results showed that the hydrogel can effectively eliminate mouse colon cancer CT26 cells, providing a strong basis for the development of new anticancer drug delivery systems.

[0004] Existing preoperative treatment methods mainly inhibit tumor growth through radiotherapy or chemotherapy, and ablate the original tumor to achieve the purpose of shrinking the tumor. As a systemic treatment method, chemotherapy, regardless of the route of administration, such as oral, intravenous or intracavitary administration, will be distributed to most organs and tissues in the body through the blood circulation. However, chemotherapy drugs have large toxic side effects. While destroying cancer cells, they also cause damage to normal tissue cells. Due to differences in the degree of drug absorption among individuals, the treatment effect is still limited. In some patients, the tumor does not regress significantly after treatment, or even has no response at all. Therefore, how to accurately apply chemotherapy drugs to tumors to improve the treatment effect and reduce the size of tumors has become an urgent problem to be solved.

[0005] Drug delivery systems based on biomaterials are an important research direction now. Hydrogels are a type of hydrophilic three-dimensional network structure gel made of natural or synthetic materials, which can release drugs accurately and slowly. Therefore, they are widely used as drug delivery carriers in tumor treatment. However, existing hydrogel-loaded drugs can only be used for chemotherapy and cannot achieve the synergistic effect of multiple pathways. Summary of the invention

[0006] The invention provides a hydrogel and a preparation method and application thereof, which solves the problem that the existing hydrogel can only load drugs for chemotherapy but cannot achieve the efficacy of synergistic effects of multiple pathways.

[0007] A method for preparing a hydrogel comprises the following steps:

[0008] In an ice bath, polydopamine-modified Fe3O4 nanoparticles are dispersed in water, and cellulose nanofibers and a catalyst are added for reaction to obtain the hydrogel; the mass ratio of the polydopamine-modified Fe3O4 nanoparticles, cellulose nanofibers and the catalyst is 0.1-0.15:0.2-0.3:0.12-0.18.

[0009] Preferably, the cellulose nanofibers are carboxylated cellulose nanofibers.

[0010] Keeping the temperature low is to avoid rapid cross-linking reactions and allow the material to fully form a hydrogel structure.

[0011] Preferably, the catalyst is N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. Adding the catalyst helps to connect the cellulose nanofibers and Fe3O4@PDA NPs to form a hydrogel. N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride reacts with the carboxylic acid groups in the cellulose nanofibers to generate an active O-acylisourea intermediate. Subsequently, the intermediate reacts with N-hydroxysuccinimide to generate N-hydroxysuccinimide ester. N-hydroxysuccinimide ester is susceptible to nucleophilic attack by the primary amino group in the polydopamine nanoparticles and is replaced, thereby achieving covalent cross-linking by forming amide bonds.

[0012] Preferably, the mass ratio of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide is 0.1-0.15:0.02-0.03.

[0013] Preferably, the mass ratio of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide is 0.115:0.023.

[0014] Preferably, the preparation method of the polydopamine-modified Fe3O4 nanoparticles is as follows: dispersing the Fe3O4 nanoparticles in a Tris-HCl solution, adding dopamine, reacting for 6-12 hours under dark conditions, collecting and freeze-drying, and obtaining polydopamine-modified Fe3O4 nanoparticles. The encapsulation technology of Fe3O4 nanoparticles and polydopamine effectively prevents the oxidation of nanoparticles. At the same time, this encapsulation method can be covalently cross-linked with cellulose nanofibers to form a hydrogel. This hydrogel can not only prevent the rapid release of nanoparticles, but also provide the hydrogel with a lasting magnetic hyperthermia treatment and chemodynamic treatment effect, and finally continuously act on the diseased part. If the polydopamine modification is omitted, the nanoparticles will be rapidly oxidized, thereby reducing the utilization rate of the particles. If the hydrogel lacks covalent cross-linking, its physical and chemical properties, such as resilience, swelling, mechanical strength, and stability will be greatly weakened.

[0015] Preferably, the concentration of the Tris-HCl solution is 8-10 mM.

[0016] Preferably, the ratio of the Fe3O4 nanoparticles to the Tris-HCl solution is 0.8-1 mg: 3-5 mL.

[0017] Preferably, the preparation method of the Fe3O4 nanoparticles is: under anaerobic conditions, dissolving FeCl2·4H2O and FeCl3·6H2O in water, adding ammonium hydroxide, and then reacting at 80°C for 1-1.5h; wherein the proportion of FeCl2·4H2O, FeCl3·6H2O, and ammonium hydroxide is 0.5-0.7g:1.4-1.9g:7-10mL.

[0018] The second object of the present invention is to protect the hydrogel prepared by the preparation method. The main purpose of preparing the hydrogel is to accurately control the release rate and dosage of the drug, thereby improving the efficacy of the drug and reducing side effects. Thanks to its high water content, excellent biocompatibility and biodegradability, the hydrogel has been widely used in the field of drug carrier preparation.

[0019] The third object of the present invention is to protect the use of the hydrogel in the preparation of magnetic heat-chemodynamic-chemotherapy combined treatment materials.

[0020] Preferably, the drug loaded in the hydrogel is 5-fluorouracil, oxaliplatin or doxorubicin.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention aims to develop a sponge-like magnetic hyperthermia hydrogel with a hollow tube structure, combining magnetic hyperthermia, chemodynamic therapy and chemotherapy to improve the therapeutic effect, reduce side effects, and provide better treatment options for colorectal cancer patients. Fe3O4@PDANPs nanoparticles and carboxylated cellulose nanofibers are covalently cross-linked to prepare a hydrogel with rapid expansion, high compressive strength and toughness. The synergistic effect of magnetic hyperthermia, chemotherapy and chemodynamic therapy at the tumor site significantly inhibits the growth of colorectal cancer tumors.

[0023] The present invention describes a sponge-like magnetic hyperthermia hydrogel with a hollow tube structure for treating colorectal cancer. The hydrogel has the characteristics of rapid expansion, high compressive strength and toughness, and has the synergistic effect of magnetic hyperthermia, chemodynamic therapy and chemotherapy. Fe3O4 nanoparticles are prepared by coprecipitation, and their surface is modified by polydopamine to obtain Fe3O4@PDA nanoparticles with good dispersibility and stability. Fe3O4@PDA nanoparticles and carboxylated cellulose nanofibers are covalently cross-linked to prepare hydrogels, thereby obtaining hyperthermia hydrogels with rapid expansion, high compressive strength and toughness. It was verified in a mouse model that the magnetic hyperthermia hydrogel can significantly inhibit the growth of rectal cancer cells and show good biosafety and biocompatibility. The present invention provides a better treatment option for patients with rectal cancer and has important clinical application value.

[0024] 1. Rapid expansion: The magnetic hyperthermia hydrogel prepared by the present invention can reach an expansion rate of about 95% within 10 seconds. The rapid expansion helps to contact with tumor tissue more effectively, thereby improving the treatment effect.

[0025] 2. High compressive strength and toughness: The prepared magnetic thermotherapy gel has good compressive strength and toughness, which can withstand the pressure brought by tumor tissue, prevent the hydrogel from rupturing, and thus improve the treatment effect.

[0026] 3. Magnetic thermal therapy: The magnetic superheated water gel prepared in this study has a thermal effect under the action of an alternating magnetic field, thus achieving magnetic thermal therapy and improving the therapeutic effect.

[0027] 4. Chemodynamic therapy: The prepared magnetic hyperthermia hydrogel can induce Fenton reaction and release Fe 2+ , produce hydroxyl free radicals, realize chemodynamic therapy, and improve the treatment effect.

[0028] 5. Synergistic therapy: The magnetic hyperthermia hydrogel prepared by the present invention can be loaded with chemotherapy drugs 5-FU, oxaliplatin or doxorubicin to achieve synergistic therapy, improve therapeutic effects and reduce side effects.

[0029] 6. Significant anti-tumor effect and biocompatibility: It has been confirmed in mouse models that magnetic hyperthermia hydrogel can significantly inhibit the growth of rectal cancer and has good biosafety and biocompatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the preparation process of Fe3O4@PDA magnetic nanoparticles;

[0031] Figure 2 Schematic diagram of the preparation of HTHSG hollow tube;

[0032] Figure 3 Detailed dimensions of the HTHSG 3D printed mold;

[0033] Figure 4 The image of the HTHSG hollow tube expanded before and after being compressed by weight;

[0034] Figure 5 Schematic diagram for the establishment and processing of cell-derived xenograft models;

[0035] Figure 6 Tumor volumes of colorectal CDX model mice in PBS group, 5-FU group, and HTHSG+5-FU group;

[0036] Figure 7 is the tumor weight of colorectal CDX model mice in PBS group, 5-FU group and HTHSG+5-FU group;

[0037] Figure 8 To establish patient-derived xenograft models, immunohistochemical analysis of CK, ki-67, MLH1, and Her2 in tumor sections from colorectal cancer patients was performed and their similarities were assessed; scale bar: 100 μm;

[0038] Fig. 9 Tumor volumes of colorectal PDX model mice in the PBS group, 5-FU group, and HTHSG+5-FU group;

[0039] Fig.10 is the tumor weight of colorectal PDX model mice in the PBS group, 5-FU group, and HTHSG+5-FU group;

[0040] Fig.11 is the thermal image of swollen HTHSG with different Fe3O4@PDA contents under the action of AMF for 10 min;

[0041] Fig.12 This is the temperature change curve of swollen HTHSG with different Fe3O4@PDA contents under the action of AMF for 10 min. DETAILED DESCRIPTION

[0042] The technical solutions in the present invention will be described clearly and completely below in conjunction with the specific implementation of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0044] Abbreviations of some substances in the present invention:

[0045] Fe3O4 nanoparticles: Fe3O4 NPs; dopamine: DA; polydopamine-modified Fe3O4 nanoparticles: Fe3O4@PDANPs; carboxylated cellulose nanofibers: CNF-C; N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride: EDC; N-hydroxysuccinimide: NHS; 5-fluorouracil: 5-Fu.

[0046] The carboxylated cellulose nanofibers used in the present invention were purchased from Guilin Qihong Technology Company.

[0047] Example 1

[0048] A method for preparing a hydrogel comprises the following steps:

[0049] Preparation of Fe3O4 NPs:

[0050] (1) At room temperature, 0.5 g of FeCl2·4H2O and 1.5 g of FeCl3·6H2O were dissolved in 150 ml of deionized water and stirred under a nitrogen atmosphere until completely dissolved.

[0051] (2) 8 mL of ammonium hydroxide was quickly added to the solution, and then stirred at 80 °C for 1 h.

[0052] (3) After the solution is cooled to room temperature, the generated precipitated particles are collected using a permanent magnet with dimensions of 10×1×0.5 cm.

[0053] (4) The precipitated particles were washed three times with deionized water and then freeze-dried to obtain Fe3O4 NPs.

[0054] Preparation of Fe3O4@PDANPs:

[0055] I. 10 mg of the prepared Fe3O4 NPs were dispersed in 50 mL of Tris-HCl solution with a concentration of 8 mM and pH = 8.5, and ultrasonically treated for 10 min to obtain a uniformly dispersed solution.

[0056] II. Add 10 mg of DA to the solution and react in the dark.

[0057] III. After 6 h, Fe3O4@PDANPs were obtained and collected by a magnet.

[0058] IV. Fe3O4@PDANPs were washed with deionized water three times and then freeze-dried at -80°C for 24 h to obtain Fe3O4@PDANPs.

[0059] Preparation of sponge-like magnetic hyperthermia hydrogel, abbreviated as HTHSG:

[0060] i. In an ice bath, the prepared Fe3O4@PDANPs were added to 5 mL of deionized water and treated with ultrasound for 5 min to ensure that the NPs were evenly dispersed in the water. Here, the gelation reaction was carried out in an ice bath.

[0061] ii. Add 0.2 g CNF-C, 0.115 g EDC and 0.023 g NHS, stir evenly under ice bath conditions to obtain a mixture.

[0062] iii. Immediately inject the stirred mixture into the mold, and solidify it into the hydrogel, i.e., the sponge-like magnetic hyperthermia hydrogel, in 10 to 20 seconds. The shape of the mold is a cube with a side length of 10 mm. The choice of the mold can be made according to actual needs. Here, a cube mold is used to facilitate subsequent experiments and analysis.

[0063] iv. Remove the prepared hydrogel from the mold and swell it in deionized water for 24 hours. This step is to allow the hydrogel to fully absorb water. Then use a vacuum freeze dryer to freeze-dry the hydrogel at -60°C for 24 hours. This step is to remove residual chemicals and make it dry for subsequent storage and use.

[0064] Example 2

[0065] A method for preparing a hydrogel comprises the following steps:

[0066] Preparation of Fe3O4 NPs:

[0067] (1) At room temperature, 0.5 g of FeCl2·4H2O and 1.4 g of FeCl3·6H2O were dissolved in 150 mL of deionized water and stirred under a nitrogen atmosphere until completely dissolved.

[0068] (2) 8 mL of ammonium hydroxide was quickly added to the solution, and then stirred at 80 °C for 1 h.

[0069] (3) After the solution is cooled to room temperature, the generated precipitated particles are collected using a permanent magnet with dimensions of 10×1×0.5 cm.

[0070] (4) The precipitated particles were washed three times with deionized water and then freeze-dried to obtain Fe3O4 NPs.

[0071] Preparation of Fe3O4@PDANPs:

[0072] I. 8 mg of the prepared Fe3O4 NPs were dispersed in 40 mL of Tris-HCl solution with a concentration of 8 mM and pH = 8.5, and ultrasonicated for 10 min to obtain a uniformly dispersed solution.

[0073] II. Add 10 mg of DA to the solution and react in the dark.

[0074] III. After 6 h, Fe3O4@PDANPs were obtained and collected by a magnet.

[0075] IV. Fe3O4@PDANPs were washed with deionized water three times and then freeze-dried at -80°C for 32 h to obtain Fe3O4@PDANPs.

[0076] Preparation of sponge-like magnetic hyperthermia hydrogel, abbreviated as HTHSG:

[0077] i. In an ice bath, the prepared Fe3O4@PDANPs were added to 5 mL of deionized water and treated with ultrasound for 5 min to ensure that the NPs were evenly dispersed in the water. Here, the gelation reaction was carried out in an ice bath.

[0078] ii. Add 0.2 g CNF-C, 0.1 g EDC and 0.02 g NHS and stir evenly under ice bath conditions to obtain a mixture.

[0079] iii. Immediately inject the stirred mixture into the mold, and solidify it into a hydrogel in 14 seconds, i.e., a sponge-like magnetic hyperthermia hydrogel. The shape of the mold is a cube with a side length of 10 mm. The choice of the mold can be made according to actual needs. Here, a cube mold is used to facilitate subsequent experiments and analysis.

[0080] iv. Remove the prepared hydrogel from the mold and swell it in deionized water for 24 hours. This step is to allow the hydrogel to fully absorb water. Then use a vacuum freeze dryer to freeze-dry the hydrogel at -60°C for 24 hours. This step is to remove residual chemicals and make it dry for subsequent storage and use.

[0081] Example 3

[0082] A method for preparing a hydrogel comprises the following steps:

[0083] Preparation of Fe3O4 NPs:

[0084] (1) At room temperature, 0.6 g of FeCl2·4H2O and 1.7 g of FeCl3·6H2O were dissolved in 150 ml of deionized water and stirred under a nitrogen atmosphere until completely dissolved.

[0085] (2) 9.5 mL of ammonium hydroxide was quickly added to the solution, and then stirred at 0°C for 1.5 h.

[0086] (3) After the solution is cooled to room temperature, the generated precipitated particles are collected using a permanent magnet with dimensions of 10×1×0.5 cm.

[0087] (4) The precipitated particles were washed three times with deionized water and then freeze-dried to obtain Fe3O4 NPs.

[0088] Preparation of Fe3O4@PDANPs:

[0089] I. 9.5 mg of the prepared Fe3O4 NPs were dispersed in 48 mL of Tris-HCl solution with a concentration of 9.5 mM and pH = 8.5, and ultrasonicated for 10 min to obtain a uniformly dispersed solution.

[0090] II. Add 10 mg of DA to the solution and react in the dark.

[0091] III. After 12 h, Fe3O4@PDANPs were obtained and collected by a magnet.

[0092] IV. Fe3O4@PDANPs were washed with deionized water three times and then freeze-dried at -80℃ for 40h to obtain Fe3O4@PDANPs.

[0093] Preparation of sponge-like magnetic hyperthermia hydrogel, abbreviated as HTHSG:

[0094] i. In an ice bath, the prepared Fe3O4@PDANPs were added to 5 mL of deionized water and treated with ultrasound for 5 min to ensure that the NPs were evenly dispersed in the water. Here, the gelation reaction was carried out in an ice bath.

[0095] ii. Add 0.24 g CNF-C, 0.12 g EDC and 0.024 g NHS, stir evenly under ice bath conditions to obtain a mixture.

[0096] iii. Immediately inject the stirred mixture into the mold, and solidify it into a hydrogel in 18 seconds, i.e., a sponge-like magnetic hyperthermia hydrogel. The shape of the mold is a cube with a side length of 10 mm. The choice of the mold can be made according to actual needs. Here, a cube mold is used to facilitate subsequent experiments and analysis.

[0097] iv. Remove the prepared hydrogel from the mold and swell it in deionized water for 24 hours. This step is to allow the hydrogel to fully absorb water. Then use a vacuum freeze dryer to freeze-dry the hydrogel at -60°C for 24 hours. This step is to remove residual chemicals and make it dry for subsequent storage and use.

[0098] Example 4

[0099] A method for preparing a hydrogel comprises the following steps:

[0100] Preparation of Fe3O4 NPs:

[0101] (1) At room temperature, 0.7 g of FeCl2·4H2O and 1.9 g of FeCl3·6H2O were dissolved in 150 ml of deionized water and stirred under a nitrogen atmosphere until completely dissolved.

[0102] (2) 10 mL of ammonium hydroxide was quickly added to the solution, and then stirred at 90 °C for 1.5 h.

[0103] (3) After the solution is cooled to room temperature, the generated precipitated particles are collected using a permanent magnet with dimensions of 10×1×0.5 cm.

[0104] (4) The precipitated particles were washed three times with deionized water and then freeze-dried to obtain Fe3O4 NPs.

[0105] Preparation of Fe3O4@PDANPs:

[0106] I. 10 mg of the prepared Fe3O4 NPs were dispersed in 50 mL of Tris-HCl solution with a concentration of 10 mM and pH = 8.5, and ultrasonicated for 10 min to obtain a uniformly dispersed solution.

[0107] II. Add 10 mg of DA to the solution and react in the dark.

[0108] III. After 12 h, Fe3O4@PDANPs were obtained and collected by a magnet.

[0109] IV. Fe3O4@PDANPs were washed with deionized water three times and then freeze-dried at -80°C for 48 h to obtain Fe3O4@PDANPs.

[0110] Preparation of sponge-like magnetic hyperthermia hydrogel, abbreviated as HTHSG:

[0111] i. In an ice bath, the prepared Fe3O4@PDANPs were added to 5 mL of deionized water and treated with ultrasound for 5 min to ensure that the NPs were evenly dispersed in the water. Here, the gelation reaction was carried out in an ice bath.

[0112] ii. Add 0.3 g CNF-C, 0.15 g EDC and 0.03 g NHS, stir evenly under ice bath conditions to obtain a mixture.

[0113] iii. Immediately inject the stirred mixture into the mold and solidify it into a hydrogel in 20 seconds, i.e., a sponge-like magnetic hyperthermia hydrogel. The shape of the mold is a cube with a side length of 10 mm. The choice of the mold can be made according to actual needs. Here, a cube mold is used to facilitate subsequent experiments and analysis.

[0114] iv. Remove the prepared hydrogel from the mold and swell it in deionized water for 24 hours. This step is to allow the hydrogel to fully absorb water. Then use a vacuum freeze dryer to freeze-dry the hydrogel at -60°C for 24 hours. This step is to remove residual chemicals and make it dry for subsequent storage and use.

[0115] Comparative Example 1

[0116] A method for preparing a hydrogel comprises the following steps:

[0117] Preparation of Fe3O4 NPs:

[0118] (1) At room temperature, 0.7 g of FeCl2·4H2O and 1.9 g of FeCl3·6H2O were dissolved in 150 ml of deionized water and stirred under a nitrogen atmosphere until completely dissolved.

[0119] (2) 10 mL of ammonium hydroxide was quickly added to the solution, and then stirred at 80 °C for 1 h.

[0120] (3) After the solution is cooled to room temperature, the generated precipitated particles are collected using a permanent magnet with dimensions of 10×1×0.5 cm.

[0121] (4) The precipitated particles were washed three times with deionized water and then freeze-dried to obtain Fe3O4 NPs.

[0122] Preparation of hydrogel:

[0123] i. Add the prepared Fe3O4 NPs to 5 mL of deionized water under ice bath conditions and use ultrasonic treatment for 5 min to ensure that the NPs are evenly dispersed in water. Here, the gelation reaction is carried out under ice bath conditions.

[0124] ii. Add 0.3 g CNF-C, 0.15 g EDC and 0.03 g NHS, stir evenly under ice bath conditions to obtain a mixture.

[0125] iii. Immediately inject the stirred mixture into the mold and solidify it into a hydrogel in 20 seconds. The shape of the mold is a cube with a side length of 10 mm. The choice of the mold can be made according to actual needs. Here, a cube mold is used to facilitate subsequent experiments and analysis.

[0126] iv. Remove the prepared hydrogel from the mold and swell it in deionized water for 24 hours. This step is to allow the hydrogel to fully absorb water. Then use a vacuum freeze dryer to freeze-dry the hydrogel at -60°C for 24 hours. This step is to remove residual chemicals and make it dry for subsequent storage and use.

[0127] The swelling capacity, compressive strength and toughness of the hydrogels prepared in Examples 2 to 4 of the present invention are substantially the same as those of the hydrogel prepared in Example 1. The following test is conducted using only the hydrogel prepared in Example 1 as an example.

[0128] Figure 1 The preparation process of Fe3O4@PDA magnetic nanoparticles is shown in the figure. The Fe3O4 nanoparticles are first prepared by coprecipitation, and then surface modified by polydopamine to obtain Fe3O4@PDA nanoparticles with excellent dispersibility and high stability.

[0129] Figure 2 This is the preparation process of the HTHSG hollow tube. First, the HTHSG mold is made using 3D printing technology. Then, the gel is accurately injected into the mold with the help of a syringe. After completing this step, the mold is demolded and expanded and freeze-dried. Finally, we successfully prepared the HTHSG hollow tube.

[0130] Figure 3 These are the dimensions of the HTHSG 3D printed mold. The inner diameter of the sleeve is accurate to 10mm, the outer diameter is 12mm, and the height is uniformly 10mm.

[0131] Figure 4 The morphological changes of the HTHSG hollow tube during weight compression and decompression are shown. After 50 cycles of compression with a weight of 200 grams, the hollow tube successfully recovered to its original structure. This result shows that the HTHSG hollow tube can still maintain its integrity and adapt to the implantation requirements of the tumor site after being squeezed. The hollow tube will not rupture under the deformation caused by normal intestinal peristalsis, thus ensuring its stability and reliability in practical applications.

[0132] Figure 5 The schematic diagram of the establishment and treatment of the cell-derived xenograft model was shown. A total of 9 tumor-bearing mice were selected and divided into three groups: the control group without 5-FU and hydrogel, the PBS group, the 5-FU group, and the HTHSG+5-FU group. All mice were exposed to an alternating magnetic field, abbreviated as AMF, for 10 minutes on days 1, 3, 5, 7, 9, and 11. The temperature changes at the tumor site were recorded using an infrared thermal imaging camera.

[0133] Figure 6 and Figure 7The changes in tumor volume and weight of mice in the PBS group, 5-FU group, and HTHSG+5-FU group in colorectal CDX, a cell line-derived xenograft tumor model, were shown. By comparative analysis, we found that compared with the control group, the tumor growth of mice in the 5-FU group was inhibited to a certain extent, and there was a significant difference in tumor weight, that is, p<0.05. The tumor in the 5-FU group was 0.46±0.08 grams, and the tumor in the control group was 0.667±0.10 grams. Further observation revealed that the anti-tumor effect of the HTHSG+5-FU group was the most significant, and its tumor volume and tumor weight were significantly better than those of the 5-FU group, that is, p<0.01; the tumor volume of the HTHSG+5-FU group was 4.667±7.65 cubic millimeters, and the tumor volume of the 5-FU group was 272.2±85.41 cubic millimeters; the tumor weight of the HTHSG+5-FU group was 0.03±0.03 grams, and the tumor weight of the 5-FU group was 0.46±0.08 grams. These results show that the HTHSG+5-FU group has a more significant effect in inhibiting tumor growth in colorectal CDX model mice.

[0134] Figure 8 A schematic diagram of the establishment and processing of cell-derived xenograft models is shown.

[0135] Fig. 9 and Fig.10 The changes in tumor volume and weight of mice in the PBS group, 5-FU group, and HTHSG+5-FU group in the colorectal PDX model mice, i.e., the patient-derived tumor xenograft model, are shown. Compared with the control group, the tumor in the HTHSG+5-FU group was significantly inhibited, with tumor weight: 0.04±0.02g in the HTHSG+5-FU group vs 0.39±0.08g in the 5-FU group vs 0.63±0.61g in the control group, p<0.01; tumor volume: 3.33±3.06mm in the HTHSG+5-FU group 3 vs 63.33±20.21mm 3 5-FU vs 127.8±70.83mm 3 Control group, P < 0.05. These results indicate that the HTHSG + 5-FU group has a more significant effect in inhibiting tumor growth in colorectal PDX model mice.

[0136] Magnetic hyperthermia treatment: Fe3O4 nanoparticles can generate heat through Neel and Brownian relaxation under an alternating magnetic field, i.e., AMF. When the heat raises the temperature in the tumor tissue to above 41-42°C, the tumor cells will achieve irreversible tissue damage or even death. The present invention compared the effects of different iron contents on the magnetic hyperthermia properties and found that the magnetic hyperthermia properties were positively correlated with the content of Fe3O4@PDA nanoparticles. After careful observation, we found that when the content of Fe3O4@PDA in the hydrogel was 10mg / mL, 20mg / mL, and 30mg / mL, respectively, the temperature changes within 10 minutes were 13.9°C, 18.6°C, and 23.2°C, respectively. This data clearly shows that there is a positive correlation between the temperature change of the hydrogel and the content of Fe3O4@PDA nanoparticles.

[0137] Fig.11 These are the thermal images of swollen HTHSG with different Fe3O4@PDA contents under the action of AMF for 10 min: CFP10 has a Fe3O4@PDA content of 10 mg / mL, CFP20 has a Fe3O4@PDA content of 20 mg / mL, CFP30 has a Fe3O4@PDA content of 30 mg / mL, and CP10 has a PDA content of 10 mg / mL.

[0138] Fig.12 This is the temperature change curve of swollen HTHSG with different Fe3O4@PDA contents under the action of AMF for 10 minutes: CFP10 is 10 mg / mL of Fe3O4@PDA content, CFP20 is 20 mg / mL of Fe3O4@PDA content, CFP30 is 30 mg / mL of Fe3O4@PDA content, and CP10 is 10 mg / mL of PDA content.

[0139] It is particularly noteworthy that when the content of Fe3O4@PDA in the hydrogel is 20 mg / mL, its temperature can reach 45.7°C after heating for 10 minutes under AMF. This temperature just meets the treatment requirement of MHT 42-45°C, which not only ensures the treatment effect but also avoids the potential damage to normal tissues caused by excessive temperature.

[0140] Therefore, based on the above experimental results, we decided to select 20 mg / mL hydrogel for subsequent experimental studies.

[0141] Chemodynamic therapy: It is a treatment method that uses the Fenton reaction between overexpressed hydrogen peroxide in the tumor microenvironment and iron ions to produce highly toxic hydroxyl radicals ·OH, thereby inducing oxidative damage to tumor cells. Fe3O4 nanoparticles can convert H2O2 into ·OH in the tumor microenvironment, achieving chemodynamic therapy

[0142] Chemotherapy: This is a disease treatment method that relies on drugs to act on cells and tissues to inhibit or eliminate cancer cells. In this study, we loaded 5-Fu into HTHSG gel to achieve precise drug release at the tumor site, thereby achieving the goal of chemotherapy.

[0143] In summary, the present invention has developed a combined magnetic heat-chemodynamic-chemotherapy treatment method, which uses a combined magnetic heat-chemodynamic-chemotherapy treatment material formed by cross-linking Fe3O4 nanoparticles and hydroxylated cellulose nanofibers to achieve combined treatment of colorectal cancer. HTHSG has the advantages of rapid expansion, high compressive strength, shape recovery and impact resistance, and can achieve combined magnetic heat-chemodynamic-chemotherapy treatment of tumors.

[0144] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0145] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a hydrogel, It is characterized in that The specific steps include: In an ice bath, Fe 3 O 4 The nanoparticles react with the cellulose nanofibers and the catalyst to obtain the hydrogel; the polydopamine-modified Fe 3 O 4 The mass ratio of nanoparticles, cellulose nanofibers and catalyst is 0.1-0.15:0.2-0.3:0.12-0.18; the catalyst is a mixture of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide.

2. A method for preparing a hydrogel according to claim 1, It is characterized in that The mass ratio of the N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide is 0.1-0.15:0.02-0.

03.

3. A method for preparing a hydrogel according to claim 2, It is characterized in that The mass ratio of the N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide is 0.115:0.

023.

4. A method for preparing a hydrogel according to claim 1, It is characterized in that The polydopamine-modified Fe 3 O 4 The preparation method of nanoparticles is as follows: Fe 3 O 4 The nanoparticles were dispersed in Tris-HCl solution, dopamine was added, and the reaction was carried out in the dark for 6-12 hours. The nanoparticles were collected and freeze-dried to obtain polydopamine-modified Fe 3 O 4 Nanoparticles.

5. A method for preparing a hydrogel according to claim 4, It is characterized in that The concentration of the Tris-HCl solution is 8-10 mM.

6. A method for preparing a hydrogel according to claim 5, It is characterized in that The Fe 3 O 4 The ratio of nanoparticles to Tris-HCl solution was 0.8-1 mg:4-5 mL.

7. A method for preparing a hydrogel according to claim 6, It is characterized in that The Fe 3 O 4 The preparation method of nanoparticles is as follows: under anaerobic conditions, FeCl 2 ·4H 2 O and FeCl 3 6H 2 O is dissolved in water, and ammonium hydroxide is added, and then reacted at 80-90°C for 1-1.5h; FeCl 2 ·4H 2 O, FeCl 3 6H 2 O. Ammonium hydroxide in the ratio of 0.5-0.7 g:1.4-1.9 g:7-10 mL.

8. The hydrogel prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the hydrogel according to claim 8 in the preparation of magnetic heat-chemodynamic-chemotherapy combined treatment materials.

10. The use according to claim 9, It is characterized in that The drug loaded by the hydrogel is 5-fluorouracil, oxaliplatin or doxorubicin.

Images