Radioactive hydrogel, preparation method and application thereof, and radioactive tumor treatment plaster

Abstract

According to the radioactive hydrogel and the preparation method and application thereof and the radioactive tumor treatment application, chitosan serves as a matrix and is crosslinked with genipin to construct a three-dimensional network, and stable loading and slow release of radionuclides can be synchronously achieved; the self-antibacterial and adhesion characteristics of the patch can reduce the infection risk and ensure the fixation of the patch, so that a safe, effective and easy-to-operate local treatment platform is provided, the prepared patch can be directly placed on a tumor bed after resection in an operation, beta or alpha rays released by radionuclides accurately and continuously act on an area where tumor cells are most likely to remain, and the effect of treating the tumor cells is achieved. Different from traditional external radiation radiotherapy, the hydrogel can continuously release radiation with a low dosage rate. The mode has a stronger biological effect (such as inhibition of reproliferation) on tumor cells, the radiosensitivity difference of different cell periods and time phases can be overcome, the killing effect is more thorough, and chitosan is proved to have certain antibacterial activity, tumor cell growth inhibition activity and immunomodulatory activity. A synergistic effect can be generated with radionuclide, and a microenvironment which is not beneficial to survival and relapse of tumor cells is constructed together with the radionuclide.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a radioactive hydrogel, its preparation method and application, and a radioactive tumor treatment patch. Background Technology

[0002] Cancer is one of the leading causes of death worldwide, with the incidence and mortality rates of malignant solid tumors such as melanoma and liver cancer rising year by year. Clinically, these tumors are often treated with a variety of methods, including surgical resection, chemotherapy, radiotherapy, targeted therapy, and immunotherapy. However, traditional external beam radiation therapy (EBRT) has certain limitations, such as difficulty in precisely controlling radiation dose distribution, radiation damage to surrounding normal tissues, and the need for patients to undergo multiple radiation treatments, increasing medical costs and adverse reactions. Therefore, developing radiotherapy methods that can stably release radioactive energy locally on the tumor while minimizing damage to normal tissues has significant clinical value.

[0003] An ideal local radiotherapy carrier should simultaneously meet the following requirements: ① It can gel in situ and adhere firmly to the tumor bed to avoid displacement; ② A three-dimensional network can control the release of radionuclides to achieve continuous, low-dose, and precise irradiation; ③ It is biodegradable and does not require secondary removal; ④ It has both antibacterial and hemostatic functions to reduce the risk of postoperative infection and bleeding. Summary of the Invention

[0004] To address the shortcomings and deficiencies of existing technologies, this invention provides a radioactive hydrogel, its preparation method and application, and a radioactive tumor treatment patch. Using chitosan as a matrix, a three-dimensional network is constructed by cross-linking with genipin, which can simultaneously achieve stable loading and slow release of radionuclides. Its own antibacterial and adhesive properties can reduce the risk of infection and ensure patch fixation, thereby providing a safe, effective, and easy-to-operate local treatment platform.

[0005] The technical solution adopted in this invention is: a radioactive hydrogel, wherein the radioactive hydrogel is composed of chitosan-genipin three-dimensional network hydrogel encapsulating ultra-small gold nanoparticles and radioactive elements, wherein the radioactive elements are labeled by ultra-small gold nanoparticles.

[0006] The radioactive element mentioned is yttrium-90 (Yttrium-90) 90 Y), Iodine-131 ( 131 I), astatine-211( 211 At), Lutetium-177 ( 177 Lu), Strontium-89 ( 89 Sr) or Lanthanum-166 ( 166 One of them is Ho.

[0007] The ultrasmall gold nanoparticles mentioned are PEG-modified ultrasmall gold nanoparticles.

[0008] A method for preparing a radioactive hydrogel includes the following steps: (1) Preparation of ultra-small gold nanoparticles: Pre-cool deionized water at 4℃, add chloroauric acid and potassium carbonate, then add sodium citrate and sodium borohydride, the color turns red-orange, then stir in an ice bath and add excess mercapto PEG, and after heating and aging, PEG-modified ultra-small gold nanoparticles AuNPs are obtained. (2) Ultra-small gold nanoparticles labeled with radioactive elements: Ultra-small gold nanoparticles AuNPs were dispersed by gently blowing with PBS at pH 7.4; a carrier-free radioactive element solution was added, PBS was added, the mixture was vortexed and placed at 37 °C for constant temperature shaking and incubation in the dark to obtain AuNPs loaded with radioactive elements. (3) Preparation of genipin-chitosan hydrogel with ultra-small gold nanoparticles: Chitosan was added to acetic acid at a ratio of 1 g / 100 mL and stirred at room temperature to obtain a colorless and transparent chitosan solution; Genipin powder was dissolved in ultrapure water and shaken until completely dissolved; Genipin aqueous solution was mixed with ultra-small gold nanoparticles; Genipin solution was slowly added dropwise to chitosan solution under stirring conditions, and stirring was continued to ensure uniform mixing; The mixture was then injected into a mold and allowed to stand to complete cross-linking, so that genipin and chitosan formed a blue-green gel network and embedded ultra-small gold nanoparticles in situ, thus obtaining a uniform genipin-chitosan hydrogel with ultra-small gold nanoparticles.

[0009] The purification process also includes the purification of radioactive hydrogels: The cross-linked radioactive hydrogel is directly placed into a dialysis bag, the air is expelled, the bag is clamped, and the bag is immersed in ultrapure water. First, rapid dialysis is performed at a volume ratio of 1:200 for 6 hours, with the water changed every hour. Then, the ratio is changed to 1:500, and dialysis is continued for 48 hours, with the water changed every 6 hours and the absorbance of the external solution at 280 nm measured until it reaches <0.01. Finally, after equilibration for 6 hours, the gel is removed, surface moisture is gently filtered off, and it is stored at 4 °C to complete the purification.

[0010] The dialysis bag is a 3.5 kDa dialysis bag.

[0011] In step (1), the mass ratio of excess mercaptoPEG to chloroauric acid is greater than 1.

[0012] Application of a radioactive hydrogel in the preparation of materials for radiotherapy of tumors.

[0013] The aforementioned material for radiotherapy of tumors is a radiopharmaceutical patch.

[0014] A radiation-induced tumor treatment patch, wherein the radiation-induced tumor treatment patch is made of a radioactive hydrogel, wherein the radioactive hydrogel is a chitosan-genipin three-dimensional network hydrogel encapsulating ultra-small gold nanoparticles AuNPs loaded with ¹³¹I, and each μg AuNPs stably loads 120 μCi ¹³¹I.

[0015] The beneficial effects of this invention are as follows: This invention provides a radioactive hydrogel, its preparation method and application, and a radioactive tumor treatment patch. Using chitosan as a matrix, a three-dimensional network is constructed by cross-linking with genipin, enabling simultaneous stable loading and slow release of radionuclides. Its inherent antibacterial and adhesive properties reduce the risk of infection and ensure patch fixation, thus providing a safe, effective, and easy-to-operate local treatment platform. The prepared patch can be directly placed on the tumor bed after surgical resection, precisely and continuously delivering β or α rays released by the radionuclides to the area most likely to retain tumor cells, achieving "targeted elimination." Unlike traditional external beam radiotherapy, the hydrogel can continuously release low-dose-rate radiation. This mode has a stronger biological effect on tumor cells (such as inhibiting re-proliferation) and can overcome the differences in radiosensitivity at different phases of the cell cycle, resulting in a more thorough killing effect. Chitosan itself has been proven to have certain antibacterial, tumor cell growth inhibition, and immunomodulatory activities. It can produce a synergistic effect with radionuclides, jointly constructing a microenvironment unfavorable to tumor cell survival and recurrence.

[0016] Chitosan, derived from abundant chitin found in nature (such as shrimp and crab shells), possesses excellent biocompatibility and is unlikely to cause rejection or severe inflammatory reactions. After fulfilling its drug release and therapeutic purpose, the hydrogel can be naturally degraded in the body into non-toxic monosaccharides or oligosaccharides, which are then absorbed or metabolized by the body. This completely avoids the pain and risks associated with traditional non-degradable implants requiring secondary surgery for removal. High local concentration, low systemic exposure: Compared to traditional intravenous radiotherapy, the patch method confines most of the radiation to the local area, greatly reducing damage to vital organs such as bone marrow, liver, and kidneys, significantly improving treatment safety.

[0017] This invention simplifies the treatment process and improves patients' quality of life. A single surgical application of a dressing enables long-term postoperative internal radiation therapy, eliminating the need for multiple trips to the hospital for external radiation therapy. Due to fewer side effects, patients experience a higher quality of life and faster recovery. The fundamental purpose of this invention is to eliminate residual tumors that are difficult to treat using conventional methods. This powerful, continuous, and precise local targeting significantly reduces the postoperative local recurrence rate, thereby improving long-term survival rates. Attached Figure Description

[0018] Figure 1 The image shows the adhesion effect of chitosan-genipin hydrogel.

[0019] Figure 2 This is a scanning electron microscope (SEM) image of chitosan-genipin hydrogel.

[0020] Figure 3 Fourier transform results for chitosan-genipin hydrogel.

[0021] Figure 4 The graph shows the solubility results of chitosan-genipin hydrogel.

[0022] Figure 5 The results of stability tests on chitosan-genipin hydrogels containing different materials.

[0023] Figure 6 This is a transmission electron microscope (TEM) image of ultrasmall gold nanoparticles.

[0024] Figure 7 The figure shows the results of the chitosan-genipin hydrogel cytotoxicity experiment.

[0025] Figure 8 Figure showing the results of animal experiments with chitosan-genipin hydrogel. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative effort are all within the scope of protection of the present invention.

[0027] Example 1 A method for preparing chitosan-genipin hydrogel, the specific method including the following steps: (1) Preparation of genipin-chitosan gel: Chitosan was added to 0.1% (v / v) acetic acid at a ratio of 1 g / 100 mL, and magnetically stirred at room temperature for 12 h to obtain a colorless and transparent 1% chitosan solution; genipin powder was dissolved in ultrapure water at a concentration of 22.3 mg / mL, and vortexed for 5 min until completely dissolved. The solution was then stirred continuously at 600 r·min. - ¹With stirring, the genipin solution was dispensed at a rate of 1 mL·min - ¹The mixture is slowly added dropwise to the chitosan solution, and stirring is continued for 30 min to ensure uniform mixing. The mixture is then poured into a mold and allowed to stand at 37°C to complete cross-linking, thus obtaining a uniform genipin-chitosan hydrogel.

[0028] (2) Purification of genipin-chitosan gel: The cross-linked genipin-chitosan hydrogel was directly loaded into a ready-to-use 3.5 kDa dialysis bag (it was cleaned at the factory and only needed to be rinsed once with ultrapure water). The air was expelled and the bag was clamped. The bag was placed in ultrapure water at 4 ℃. First, the volume ratio was 1:200 for rapid dialysis for 6 h, and the water was changed every 1 h. Then, the ratio was changed to 1:500 and the gel was allowed to stand for dialysis for 48 h. During this period, the water was changed every 6 h and the absorbance of the external liquid at 280 nm was measured until it was <0.01. Finally, the gel was equilibrated for 6 h. The surface water was removed and the gel was filtered off. The gel was stored at 4 ℃ to complete the purification.

[0029] Determination of properties and characterization of genipin-chitosan gel Adhesion performance test of genipin-chitosan gel: such as Figure 1 As shown, a healthy mouse weighing over 20g was used, and its viscera were removed by cervical dislocation. These viscera were then adhered to genipin-chitosan gel, and their adhesion properties were tested. During the adhesion process, the gel was rinsed with pure water to further mimic adhesion in a bodily fluid environment. Adhesion experiments verified that the genipin-chitosan gel material of this invention exhibits excellent adhesion properties to various biological tissues (including the heart, lungs, liver, kidneys, and pancreas of mice) as well as synthetic materials such as polyester fibers and glass. These results demonstrate that the gel possesses broad and robust interfacial bonding capabilities, providing crucial performance support for its stable application as a medical dressing or tissue engineering scaffold.

[0030] Scanning electron microscopy analysis of genipin-chitosan gel: (e.g.) Figure 2 As shown, a suitable volume of purified genipin-chitosan gel was placed in a 15 mL centrifuge tube and frozen overnight at -80°C. The gel was then freeze-dried to completely remove water, preventing structural collapse under high vacuum. A flat small piece (approximately 5 mm × 5 mm) was then attached to conductive adhesive. If cross-section observation was required, it could be quickly and brittlely broken off with a blade. A 5–10 nm thick gold layer was then sputtered in an ion sputtering system to improve conductivity and prevent charge accumulation. Finally, the sample was placed in the scanning electron microscope sample chamber. Low or high vacuum mode was selected, with an accelerating voltage of 2–15 kV and a magnification of 200×–5000×. Surface or cross-sectional morphology images were acquired to obtain the typical microstructure of its layered structure, effectively preventing the loss of ultra-small gold nanoparticles and improving labeling. 131 The stability of I-type ultra-small gold nanoparticles achieves excellent local radiotherapy results.

[0031] Genipin-chitosan gel Fourier transform infrared (FTIR) test: such as Figure 3As shown, the chitosan-genipin crosslinked samples were characterized using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Before testing, the samples were vacuum-dried to minimize moisture interference. The spectral results showed that the crosslinked samples did not exhibit significant moisture content at the typical 1645 cm⁻¹. -1 A sharp, independent new peak was observed at 1523 cm, but at 1523 cm... -1 A new peak appeared at [location]; simultaneously, the characteristic primary amine peak of chitosan (~1560 cm⁻¹) was observed. -1 The intensity of the crosslinking is significantly reduced. Combined with the visually striking deep blue color of the sample after the reaction, it can be concluded that the crosslinking reaction has indeed occurred. The absence of isolated C=N characteristic peaks in the spectrum is likely due to the OH vibration peak (~1640 cm⁻¹) of residual water in the gel. -1 This is due to the overlap with the target peak; while 1523 cm -1 The new peak can be attributed to structures such as secondary amines generated in the reaction. The weakening of the primary amine peak and the color change together constitute a valid chain of evidence proving successful cross-linking.

[0032] To assess its degradability, the in vitro dissolution rate of the genipin-chitosan hydrogel was determined using an enzymatic hydrolysis method. Figure 4 As shown, the specific method was as follows: the gel sample was first freeze-dried to constant weight, then immersed in PBS solution containing 1 mg / mL lysozyme, and degraded under constant temperature and shaking conditions at 37°C. For eight consecutive days, samples were taken out at regular intervals each day, freeze-dried, and their remaining mass was measured. The results showed that the gel with an initial mass (m0) of approximately 30 mg decreased to 8.1 mg on the eighth day, indicating a significant mass loss. This result demonstrates that the gel has a relatively fast degradation rate under enzymatic hydrolysis conditions simulating physiological environments, preliminarily confirming its good solubility and biocompatibility.

[0033] Example 2 like Figure 5 and Figure 6 As shown, the material encapsulated in the genipin-chitosan gel of this invention has undergone stability testing, and ultra-small gold nanoparticles were selected for nuclide labeling.

[0034] Preparation of ultrasmall gold nanoparticles: such as Figure 6As shown, 100 mL of pre-cooled deionized water at 4℃ was added, followed by 1 mL of 2.5% HAuCl4·3H2O (63.5 μmol of gold ions) + 1 mL of 0.2 M K2CO3, then 1 mL of 18% trisodium citrate dihydrate, and finally 0.5 mL of 2.5 mg / 5 mL NaBH4. The color turned red-orange, and the mixture was stirred in an ice bath for 5 min. Then, 40 mg of SH-PEG 5000 (with a mass ratio greater than 1 to chloroauric acid) was added, and the mixture was stirred at room temperature or slightly heated for 30–60 min. After molding, the size of the ultrasmall gold nanoparticles was measured by transmission electron microscopy (TEM). TEM characterization showed that the prepared ultrasmall gold nanoparticles were uniform in size, with a particle size less than 10 nm. Nanoparticles in this size range, due to their high specific surface area and surface energy, can bind more nuclides. 131 I, and is easily and uniformly encapsulated and stably loaded in a viscoelastic genipin-chitosan hydrogel three-dimensional network structure through physical adsorption or electrostatic interaction.

[0035] Labeling of nuclides with ultrasmall gold nanoparticles: 1 μg of ultrasmall gold nanoparticles (AuNPs) was placed in a 1.5 mL low-adsorption EP tube, and 10 μL of 0.1 M pH 7.4 PBS buffer was added; 120 μCiNa¹³¹I solution was added, and PBS was added to a total volume of 100 μL. The tube was rapidly vortexed for 5 s; it was then incubated at 600 rpm in the dark for 10 min in a 37 ℃ constant-temperature shaker; the solution was purified by ultrafiltration, and the radioactivity of the filtrate and ultrasmall gold nanoparticles was measured. The labeling rate was calculated to be >95%, meaning that 1 μg of AuNPs can stably load 120 μCi¹³¹I with a specific activity of 1.2 × 10¹⁰. 5 μCi·g - ¹.

[0036] Genipin-chitosan gel encapsulating ultra-small gold nanoparticles: Chitosan was first dissolved in 0.1% acetic acid to obtain a 1% solution, and genipin 22.3 mg / mL aqueous solution was mixed with labeled... 131 I. The ultra-small gold nanoparticles are mixed evenly and immediately injected into a mold. They are then allowed to stand at 37°C for cross-linking, allowing genipin and chitosan to form a blue-green gel network and in situ embed the ultra-small gold nanoparticles, thus forming a radioactive tumor treatment patch (CS-GP RadioPatch, abbreviated as CGR) based on chitosan-genipin hydrogel.

[0037] Stability tests of different materials encapsulated in genipin-chitosan gel: To evaluate the stability of different nanocarriers in hydrogels and their impact on radionuclide retention capacity, 131I was labeled onto four materials: gold nanoparticles, ultra-small gold nanoparticles, graphene, and microspheres, and then composited into genipin-chitosan hydrogels. For example... Figure 5 As shown, the composite gel samples were placed in deionized water and PBS solution, respectively, and the radioactivity intensity was monitored periodically to characterize the retention of radionuclides. Comparative experiments revealed significant differences in the stability of different carriers in the hydrogel. Among them, the ultrasmall gold nanoparticles exhibited excellent stability, with a radionuclide retention rate approaching 99% in both media. This result demonstrates that ultrasmall gold nanoparticles can significantly reduce the retention of therapeutic radionuclides. 131 The unexpected loss of I ensures that it is efficiently fixed to the target site, significantly enhancing the precision and efficacy of local treatment.

[0038] like Figure 7 and Figure 8 As shown, the "postoperative in-situ disinfection" effect of genipin-chitosan gel is verified: (1) Cytotoxicity test of genipin-chitosan gel: To verify the biocompatibility of the hydrogel material of this invention, the cytotoxicity of its extract was systematically evaluated using the CCK-8 method. Figure 7 As shown, using mouse embryonic fibroblasts (3T3 cells) as a model, the material was extracted from the cell culture medium under different time conditions to obtain a series of extracts. After co-culturing 3T3 cells with each extract, cell viability was quantified by detecting absorbance at 450 nm. Experimental results showed that even under the extract conditions corresponding to the longest extraction time, the relative viability of 3T3 cells remained as high as approximately 92%, with no significant difference compared to the negative control group. This data fully demonstrates that the hydrogel material of this invention did not produce detectable cytotoxicity under different extraction conditions, exhibiting excellent in vitro biocompatibility.

[0039] (2) Genipin-chitosan gel animal experiment: Constructing an immunodeficient BALB / c-nu nude mouse subcutaneous xenograft model: 5×10⁻⁶ g of genipin-chitosan gel was subcutaneously injected into the lateral thigh of the right hind limb. 6 Log-phase human HepG2 cells (containing 30% Matrigel) were collected, and once the tumors reached a suitable size, they were randomly divided into an experimental group and a control group. In both groups, a 3 mm transverse incision was made on the side of the tumor, and 3 / 4 of the tumor was precisely removed using microscissors (leaving 1 / 4 of the basal tumor remnant). After thorough hemostasis, the experimental group immediately received 500 µL of genipin-chitosan hydrogel (with labeled...) 131 Ultra-small gold nanoparticles of radionuclide I (radioactivity ≈ 1 mCi) were implanted, while the control group received an equal amount of non-radioactive blank gel. The skin was then glued together with tissue adhesive and iodine was applied. Figure 8As shown, in an eight-day in vivo tumor suppression experiment, mice in the blank control group developed obvious tumor tissue; in stark contrast, the experimental group CGR-1 and CGR-2 (i.e., loaded tumor tissue) showed significant tumor growth. 131 No significant tumor growth was observed in either the genipin-chitosan hydrogel patch containing I-labeled ultrasmall gold nanoparticles. This result confirms that the radionuclide composite hydrogel patch of the present invention can effectively inhibit or even completely prevent tumor growth, demonstrating significant local therapeutic efficacy.

[0040] The specific embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding its defined scope. Although the invention has been detailed and described in the accompanying drawings and foregoing description, such descriptions are considered illustrative or exemplary rather than restrictive. It should be understood that changes and modifications can be made by those skilled in the art within the scope of the following claims.

Claims

1. A radioactive hydrogel, characterized in that, The radioactive hydrogel is composed of chitosan-genipin three-dimensional network hydrogel encapsulating ultra-small gold nanoparticles and radioactive elements, wherein the radioactive elements are labeled by ultra-small gold nanoparticles.

2. The radioactive hydrogel according to claim 1, characterized in that, The radioactive element mentioned is yttrium-90 (Yttrium-90) 90 Y), Iodine-131 ( 131 I), astatine-211( 211 At), Lutetium-177 ( 177 Lu), Strontium-89 ( 89 Sr) or Lanthanum-166 ( 166 One of them is Ho.

3. The radioactive hydrogel according to claim 1, characterized in that, The ultrasmall gold nanoparticles mentioned are PEG-modified ultrasmall gold nanoparticles.

4. A method for preparing the radioactive hydrogel according to claim 1, characterized in that, Includes the following steps: (1) Preparation of ultra-small gold nanoparticles: Pre-cool deionized water at 4℃, add chloroauric acid and potassium carbonate, then add sodium citrate and sodium borohydride, the color turns red-orange, then stir in an ice bath and add excess mercapto PEG, and after heating and aging, PEG-modified ultra-small gold nanoparticles AuNPs are obtained. (2) Labeling radioactive elements with ultra-small gold nanoparticles: Add PBS buffer solution of pH 7.4 to ultra-small gold nanoparticles, add radioactive element solution, place at 37 ℃ and shake, and obtain AuNPs labeled with radioactive elements after ultrafiltration purification; (3) Preparation of genipin-chitosan hydrogel with ultra-small gold nanoparticles: Chitosan was added to acetic acid at a ratio of 1 g / 100 mL and stirred at room temperature to obtain a colorless and transparent chitosan solution; Genipin powder was dissolved in ultrapure water and shaken until completely dissolved; Genipin aqueous solution was mixed with ultra-small gold nanoparticles; Genipin solution was slowly added dropwise to chitosan solution under stirring conditions, and stirring was continued to ensure uniform mixing; The mixture was then injected into a mold and allowed to stand to complete cross-linking, so that genipin and chitosan formed a blue-green gel network and embedded ultra-small gold nanoparticles in situ, thus obtaining a uniform genipin-chitosan hydrogel with ultra-small gold nanoparticles.

5. The preparation method according to claim 4, characterized in that, The purification process also includes the purification of radioactive hydrogels: The cross-linked radioactive hydrogel is directly placed into a dialysis bag, the air is expelled, the bag is clamped, and the bag is immersed in ultrapure water. First, rapid dialysis is performed at a volume ratio of 1:200 for 6 hours, with the water changed every hour. Then, the ratio is changed to 1:500, and dialysis is continued for 48 hours, with the water changed every 6 hours and the absorbance of the external solution at 280 nm measured until it reaches <0.

01. Finally, after equilibration for 6 hours, the gel is removed, surface moisture is gently filtered off, and it is stored at 4 °C to complete the purification.

6. The preparation method according to claim 5, characterized in that, The dialysis bag is a 3.5 kDa dialysis bag.

7. The preparation method according to claim 4, characterized in that, In step (1), the mass ratio of excess mercaptoPEG to chloroauric acid is greater than 1.

8. The application of the radioactive hydrogel of claim 1 in the preparation of radiotherapy materials for tumors.

9. The application according to claim 8, characterized in that, The aforementioned material for radiotherapy of tumors is a radiopharmaceutical patch.

10. A radiation-induced tumor treatment patch, characterized in that, The radioactive tumor treatment patch is made of the radioactive hydrogel described in claim 1. The radioactive hydrogel is a chitosan-genipin three-dimensional network hydrogel encapsulating ultra-small gold nanoparticles AuNPs loaded with ¹³¹I, with each μg AuNPs stably loaded with 120 μCi ¹³¹I.

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