Preparation method of a nanocomposite for magnetic resonance imaging-guided ferroptosis photodynamic synergistic therapy

Abstract

The present invention relates to the field of biomedical materials, and discloses a preparation method of a nanocomposite material for magnetic resonance imaging-guided ferroptosis-photodynamic synergistic therapy. The present invention takes iron oxide nanoparticles as the core, after loading glucose oxidase, chitosan is coated on the surface through electrostatic adsorption, and then the photodynamic reagent IR820 is loaded to obtain a nanocomposite material. This composite material ingeniously combines the biochemical characteristics of ferroptosis to generate oxygen with the application defect of photodynamic therapy consuming oxygen, realizing magnetic resonance imaging-guided ferroptosis-photodynamic synergistic therapy. The nanocomposite material prepared by the present invention not only has good biocompatibility, phototoxicity to tumor cells, but also excellent targeting performance, providing a feasible and effective strategy for the treatment of superficial cancers.

Description

Technical Field

[0001] The invention relates to the field of biomedical materials, and in particular to a method for preparing a nano-composite material for ferroptosis-photodynamic synergistic therapy guided by magnetic resonance imaging. Background Art

[0002] Compared with traditional treatment options, photodynamic therapy (PDT) has the advantages of less damage and controllable time and space. However, the PDT process requires continuous consumption of O2, and the hypoxic microenvironment at the tumor site is one of the important reasons that hinder the efficacy of PDT.

[0003] Ferroptosis is a type of programmed cell death, in which iron ions flow into the cell and the iron pool in the cell increases. In previous experiments, the inventors found that excess iron ions in the cell and H2O2 in the tumor cells can produce ROS and molecular oxygen through the Fenton reaction, which can just replenish the oxygen consumption of PDT. Therefore, ferroptosis can be used as a strategy for combined PDT treatment, but the limited content of H2O2 in the tumor greatly limits the practical application of ferroptosis.

[0004] Ferroferric oxide nanoparticles have superparamagnetism and are often used as medical contrast agents; they can also actively target and aggregate to the tumor site under the action of an external magnetic field, and can also passively target and aggregate in tumor tissue through the enhanced permeability and retention (EPR) effect of the tumor, so they are widely studied as drug carriers. The inventors found in previous experiments that ferroferric oxide nanoparticles can increase the intracellular iron ion concentration and induce ferroptosis of tumor cells in addition to the above-mentioned effects. Therefore, they can not only treat tumors through their own ferroptosis-inducing effect of tumor cells, but also provide oxygen for PDF and perform synergistic treatment with PDT. However, ferroferric oxide nanoparticles also have the disadvantages of being insoluble in water and having poor biocompatibility, which limits their application. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a nanocomposite material for ferroptosis photodynamic synergistic therapy guided by magnetic resonance imaging. The present invention first synthesizes citric acid-coated ferroferric oxide nanoparticles by ultrasonic coprecipitation, then loads glucose oxidase GOD for decomposing tumor energy substance β-D glucose, and then modifies chitosan on its surface by electrostatic adsorption to improve the dispersibility and biocompatibility of ferroferric oxide nanoparticles in water, and finally loads photosensitizer indocyanine green IR820 for photodynamic therapy, and finally obtains a nanocomposite material for ferroptosis photodynamic synergistic therapy with high magnetic resonance imaging-mediated targeting, good biocompatibility and good anti-tumor performance.

[0006] The specific technical solution of the present invention is as follows: A preparation method of a ferroptosis-photodynamic synergistic therapy nanocomposite guided by magnetic resonance imaging, comprising the following steps:

[0007] Step 1): Preparation of citric acid-coated iron oxide nanoparticles (MNPs): Dissolve 4.3 - 4.5 g of FeCl3 and 2.6 - 2.8 g of FeCl2·4H2O in 80 mL of deionized water, perform ultrasonic stirring reaction in a N2 atmosphere at 60 - 80 °C, then immediately add 15 - 25 mL of ammonia water solution to the obtained reaction mixture, keep warm and continue ultrasonic stirring, add 3 - 5 mL of citric acid aqueous solution, raise the temperature to 85 - 95 °C, and perform reflux reaction; Cool the obtained reaction mixture to room temperature, rinse, perform magnetic separation, vacuum dry, and grind to obtain citric acid-coated iron oxide nanoparticles MNPs.

[0008] Step 2): Immobilization of glucose oxidase (GOD): Weigh 0.1 - 0.3 g of citric acid-coated iron oxide nanoparticles and ultrasonically disperse them in 50 mL of phosphate buffer solution, add 0.1 - 0.2 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.07 - 0.09 g of N-hydroxysuccinimide for activation under stirring; Then add 8 - 12 mg of glucose oxidase, stir and collect, after collection, centrifuge, discard the supernatant, wash, and freeze-dry to obtain MNPs-GOD.

[0009] Step 3): Surface modification with chitosan (CS): Weigh 0.3 - 0.5 g of MNPs-GOD and ultrasonically disperse it in 50 ml of phosphate buffer solution, and add 0.13 - 0.17 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.06 - 0.10 g of N-hydroxysuccinimide for activation under stirring; Weigh 0.7 - 0.9 g of chitosan, ultrasonically disperse it in 100 mL of phosphate buffer solution, and add it to the reaction system after the activation is completed, stir and react, after the reaction is completed, centrifuge and separate, discard the supernatant, wash, and freeze-dry to obtain MNPs-GOD@CS.

[0010] Step 4): Loading of the photodynamic reagent indocyanine green IR820: Weigh 8 - 12 mg of indocyanine green IR820, ultrasonically disperse it in 10 mL of deionized water to obtain an IR820 dispersion; Weigh 8 - 12 mg of MNPs-GOD@CS and ultrasonically disperse it in 10 mL of deionized water to obtain an MNPs-GOD@CS dispersion; Under light-shielded conditions, add the IR820 dispersion to the MNPs-GOD@CS dispersion, stir, centrifuge, discard the supernatant, wash to remove free IR820, rapidly freeze at -85 °C to -75 °C for 5 - 7 h, and freeze-dry to obtain MNPs-GOD@CS / IR820, which is the ferroptosis-photodynamic synergistic therapy nanocomposite guided by magnetic resonance imaging.

[0011] The present invention first synthesizes citric acid-coated iron oxide nanoparticles by ultrasonic co-precipitation method, then loads glucose oxidase GOD for decomposing the tumor energy substance β-D glucose, and then modifies chitosan on its surface by electrostatic adsorption to improve the dispersibility and biocompatibility of the iron oxide nanoparticles in water. Finally, the photosensitizer indocyanine green IR820 for photodynamic therapy is loaded, and finally a ferroptosis-photodynamic synergistic therapy nanocomposite with high targeting, good biocompatibility and good anti-tumor performance mediated by magnetic resonance imaging is obtained.

[0012] In the present invention, indocyanine green IR820, as a third-generation photosensitizer, has the characteristics of hygroscopicity, easy oxidation, single chemical composition, good water solubility, high specific enrichment in tumor tissues and fast clearance rate in normal tissues, and can be used for photodynamic therapy of tumors.

[0013] However, the photodynamic therapy process requires continuous consumption of O2, and the hypoxic microenvironment in the tumor site hinders the efficacy of photodynamic therapy. Therefore, the present invention introduces iron oxide nanoparticles. Superparamagnetic iron oxide nanoparticles can not only actively target and aggregate towards the tumor site under the action of an external magnetic field, but more importantly, they can also increase the intracellular iron ion concentration and induce ferroptosis in tumor cells. More ingeniously, the excessive iron ions in the cells and H2O2 in the tumor cells during the ferroptosis process can generate ROS and molecular oxygen through the Fenton reaction, which can exactly supplement the oxygen consumption of photodynamic therapy. Therefore, the ferroptosis therapy adopted in the present invention can promote the effect of photodynamic therapy.

[0014] However, the content of H2O2 in the tumor is limited, which greatly limits the ferroptosis effect; in addition, iron oxide nanoparticles also have disadvantages such as insoluble in water and poor biocompatibility, which limit their application. Therefore, the nanocomposite of the present invention also introduces glucose oxidase (GOD), which can decompose β-d glucose in the tumor microenvironment to provide the reactant H2O2 for the ferroptosis Fenton reaction, and β-d glucose is an essential energy substance for the division and growth of tumor cells. When β-d glucose is decomposed, it will inhibit the growth of tumor cells in a "starvation therapy" manner. Finally, the present invention selects pH-responsive chitosan for surface modification, which can improve the biocompatibility of the nanoparticles, reduce renal clearance, prolong the half-life in blood circulation, and enhance the accumulation in the tumor site.

[0015] Preferably, in step 1), the volume concentration of the ammonia water solution is 18-22%, and the concentration of the citric acid water solution is 0.4-0.6 g / mL.

[0016] Preferably, in step 1): the power of the ultrasonic stirring reaction is 120 - 140 W, the ultrasonic frequency is 15 - 25 KHz, the rotation speed is 800 - 1200 rpm, the ultrasonic stirring reaction time is 20 - 40 min; the time for continuous ultrasonic stirring during heat preservation is 20 - 40 min.

[0017] Preferably, in step 1): the reflux reaction time is 50 - 70 min; the vacuum drying temperature is 50 - 70 °C, and the time is 20 - 30 h.

[0018] Preferably, in step 2): the pH of the phosphate buffer solution is 5.6 - 6.0, the power of ultrasonic dispersion is 120 - 140 W, and the ultrasonic frequency is 15 - 25 KHz.

[0019] Preferably, in step 2): the activation time is 110 - 130 min; the stirring and collection time is 10 - 14 h, the centrifugation rotation speed is 11000 - 13000 rpm, the centrifugation temperature is 3 - 7 °C, and the centrifugation time is 5 - 15 min.

[0020] Preferably, in step 3): the pH of the phosphate buffer solution is 5.6 - 6.0, the activation time is 110 - 130 min; the stirring reaction time is 70 - 75 h, the centrifugation rotation speed is 11000 - 13000 rpm, the centrifugation temperature is 3 - 7 °C, and the centrifugation time is 5 - 15 min.

[0021] Preferably, in step 4): the stirring rotation speed is 600 - 1000 rpm, the stirring time is 10 - 15 h, the centrifugation rotation speed is 11000 - 13000 rpm, the centrifugation temperature is 3 - 7 °C, the centrifugation time is 5 - 15 min, and the freeze-drying time is 20 - 30 h.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] (1) Superparamagnetic iron oxide nanoparticles can be imaged under magnetic resonance (MRI), and are expected to construct a nano-platform for integrated diagnosis and treatment; superparamagnetic iron oxide nanoparticles can actively target and aggregate towards the tumor site under the action of an external magnetic field; at the same time, the nanoparticles will passively target and aggregate in tumor tissues through the enhanced permeability and retention (EPR) effect of tumors. The combination of active targeting and passive targeting makes this composite material have excellent targeting properties and low systemic toxicity; superparamagnetic iron oxide nanoparticles can increase the intracellular iron ion concentration and induce ferroptosis of tumor cells.

[0024] (2) Glucose oxidase (GOD) can decompose β-d-glucose in the tumor microenvironment to provide the reactant H2O2 for the ferroptosis Fenton reaction. Moreover, β-d-glucose is an essential energy source for tumor cell division and growth. When β-d-glucose is decomposed, it inhibits tumor cell growth in a way of "starvation therapy".

[0025] (3) The photosensitizer new indocyanine green IR820, as the third-generation photosensitizer, has the characteristics of hygroscopicity, easy oxidation, single chemical composition, good water solubility, high specific enrichment in tumor tissues, and fast clearance rate in normal tissues.

[0026] (4) Selecting pH-responsive chitosan for surface modification can improve the biocompatibility of nanoparticles, reduce renal clearance, extend the half-life in blood circulation, and enhance the accumulation at the tumor site. Detailed implementation mode

[0027] The present invention will be further described below in conjunction with embodiments.

[0028] Example 1

[0029] Step 1): Preparation of citric acid-coated iron oxide nanoparticles (MNPs): Dissolve 4.40 g of FeCl3 and 2.70 g of FeCl2·4H2O in 80 mL of deionized water, stir mechanically at a stable speed of 1000 rpm, reflux and react in a N2 atmosphere, ultrasonically stir at 70 °C for 30 min (130 W, 20 KHz), then immediately add 20 mL of ammonia water with a volume concentration of 20% to the reaction mixture, maintain the temperature at 70 °C, continue ultrasonically stirring for 30 min, then add 4 mL of 0.5 g / mL citric acid aqueous solution to the mixture, slowly raise the reaction temperature to 90 °C, and reflux and react for 60 min. Subsequently, cool the reaction mixture to room temperature, wash it repeatedly with ultrapure water, separate the sample from the supernatant using a permanent magnet, and dry it in vacuum at 60 °C for 24 h. After grinding, the product MNPs are obtained.

[0030] Step 2): Immobilization of glucose oxidase (GOD): Weigh 0.20 g of the MNPs prepared in Step 2), disperse them ultrasonically (130 W, 20 KHz) into 50 ml of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), add 0.15 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.08 g of N-hydroxysuccinimide under mechanical stirring to activate for 120 min. Then add 10 mg of GOD, stir and collect for 12 h. After the collection, centrifuge (12000 rpm, 5 °C) for 10 min, discard the supernatant, wash it repeatedly with deionized water, and then freeze-dry for 24 h to obtain continuous MNPs-GOD.

[0031] Step 3): Surface modification of chitosan (MNPs-GOD@CS): Weigh 0.40 g of MNPs-GOD prepared in Step 2), ultrasonically disperse it in 50 ml of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), and add 0.15 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 0.08 g of N-hydroxysuccinimide under mechanical stirring to activate for 120 min. Weigh 0.80 g of chitosan, ultrasonically disperse it in 100 mL of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), and add it to the reaction system after the activation is completed, and stir for 72 h. After the reaction is completed, centrifuge (12,000 rpm, 5 °C) for 10 min for separation, discard the supernatant, and wash 4 times with deionized water. Freeze-dry for 24 h to obtain MNPs-GOD@CS.

[0032] Step 4): Loading of the photodynamic reagent indocyanine green (IR820): Weigh 10 mg of IR820 and ultrasonically disperse it in 10 mL of deionized water; weigh 10 mg of MNPs-GOD@CS prepared in Step 3) and ultrasonically disperse it in 10 mL of deionized water. Add the IR820 dispersion to the MNPs-GOD@CS dispersion and mechanically stir for 12 h. After stirring is completed, centrifuge (12,000 rpm, 5 °C) for 10 min, discard the supernatant, and wash 4 times with deionized water to remove free IR820. Then quickly freeze at -80 °C in a cryogenic refrigerator for 6 h, and then freeze-dry for 24 h to obtain

[0033] MNPs-GOD@CS / IR820.

[0034] The prepared MNPs-GOD@CS / IR820 nanocomposite has good in vitro anti-tumor performance. In the phototoxicity experiment of mouse melanoma cells, the cells were co-incubated with the drug for 12 h, and then irradiated with 808 nm, 0.6 W / cm 2 laser for 10 min, and then incubated for 24 h. The cell viabilities of the blank control, MNPs@CS, MNPs-GOD@CS, IR820, and MNPs-GOD@CS / IR820 groups were 100±0%, 98.03±7.26%, 96.78±2.56%, 46.32±8.21%, and 11.91±0.59% respectively. Compared with other groups, the cell viability of the MNPs-GOD@CS / IR820 treatment group was the lowest.

[0035] Example 2

[0036] Step 1): Preparation of citric acid-coated iron oxide nanoparticles (MNPs): Dissolve 4.40 g of FeCl3 and 2.70 g of FeCl2·4H2O in 80 mL of deionized water. Use an ultrasonic cleaner with a working power of 130 W and a repetition frequency of 20 KHz for ultrasonic treatment, accompanied by stable mechanical stirring at a speed of 1000 rpm. React under reflux in an N2 atmosphere, perform ultrasonic stirring at 70 °C for 30 min. Subsequently, immediately add 20 mL of ammonia water solution with a volume concentration of 20% to the reaction mixture, maintain the temperature at 70 °C, continue ultrasonic stirring for 30 min, then add 4 mL of 0.5 g / mL citric acid aqueous solution to the mixture, slowly raise the reaction temperature to 90 °C, and reflux for 60 min. Subsequently, cool the reaction mixture to room temperature, wash it multiple times with ultrapure water, separate the sample from the supernatant using a permanent magnet, and dry it in a vacuum at 60 °C for 24 h. After grinding, the product MNPs is obtained.

[0037] Step 2): Immobilization of glucose oxidase (GOD): Weigh 0.20 g of the MNPs prepared in Step 2) and ultrasonically disperse it (130 W, 20 KHz) into 50 ml of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8). Add 0.15 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.08 g of N-hydroxysuccinimide under mechanical stirring for activation for 120 min. Then add 10 mg of GOD, stir and collect for 12 h. After collection, centrifuge (12000 rpm, 5 °C) for 10 min, discard the supernatant, wash it multiple times with deionized water, and then freeze-dry for 24 h to obtain continuous MNPs-GOD.

[0038] Step 3): Surface modification with chitosan (MNPs-GOD@CS): Weigh 0.40 g of the MNPs-GOD prepared in Step 2), ultrasonically disperse it in 50 ml of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), and add 0.15 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.08 g of N-hydroxysuccinimide under mechanical stirring for activation for 120 min. Weigh 0.80 g of chitosan, ultrasonically disperse it in 100 mL of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), and add it to the reaction system after the activation is completed, and stir for 72 h. After the reaction, centrifuge (12000 rpm, 5 °C) for 10 min for separation, discard the supernatant, and wash it 4 times with deionized water. Freeze-dry for 24 h to obtain MNPs-GOD@CS.

[0039] Step 4): Loading the photosensitizer indocyanine green (IR820): Weigh 10 mg of IR820 and ultrasonically disperse it in 10 mL of deionized water; weigh 10 mg of the MNPs-GOD@CS prepared in step 3) and ultrasonically disperse it in 10 mL of deionized water. Add the IR820 dispersion to the MNPs-GOD@CS dispersion and mechanically stir for 12 h. After stirring, centrifuge (12000 rpm, 5 °C) for 10 min, discard the supernatant, and wash 4 times with deionized water to remove free IR820. Then, rapidly freeze at -80 °C in an ultra-low temperature refrigerator for 6 h, and then freeze-dry for 24 h to obtain MNPs-GOD@CS / IR820.

[0040] The prepared MNPs-GOD@CS / IR820 nanocomposite has good in vitro anti-tumor performance. In the phototoxicity experiment of mouse melanoma cells, the cells were co-incubated with the drug for 12 h, and then irradiated with a laser at 808 nm and 0.6 W / cm 2 for 10 min, and then incubated for another 24 h. The cell viabilities of the blank control, MNPs@CS, MNPs-GOD@CS, IR820, and MNPs-GOD@CS / IR820 groups were 100%, 98.03±4.12%, 99.98±5.28%, 46.91±3.35%, and 7.82±1.17%, respectively. Compared with other groups, the cell viability of the BF cells in the MNPs-GOD@CS / IR820 treatment group was the lowest.

[0041] Example 3

[0042] Step 1): Preparation of citric acid-coated iron oxide nanoparticles (MNPs): Dissolve 4.40 g of FeCl3 and 2.70 g of FeCl2·4H2O in 80 mL of deionized water, use an ultrasonic cleaner with a working power of 130 W and a repetition frequency of 20 KHz for ultrasonic treatment, accompanied by stable mechanical stirring at a speed of 300 rpm, reflux and react in an N2 atmosphere, ultrasonic stir at 70 °C for 30 min, then immediately add 20 mL of 20% ammonia water solution to the reaction mixture, maintain the temperature at 70 °C, continue ultrasonic stirring for 30 min, then add 4 mL of 0.5 g / mL citric acid aqueous solution to the mixture, slowly raise the reaction temperature to 90 °C, and reflux and react for 60 min. Subsequently, cool the reaction mixture to room temperature, wash it multiple times with ultrapure water, separate the sample from the supernatant using a permanent magnet, and dry it in vacuum at 60 °C for 24 h. After grinding, the product MNPs is obtained.

[0043] Step 2): Immobilization of glucose oxidase (GOD): Weigh 0.20 g of the MNPs prepared in step 2) and ultrasonically disperse (130 W, 20 KHz) it into 50 ml of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8). Add 0.15 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.08 g of N-hydroxysuccinimide under mechanical stirring to activate for 120 min. Then add 10 mg of GOD, stir and collect for 12 h. After collection, centrifuge (12,000 rpm, 5 °C) for 10 min, discard the supernatant, and wash with deionized water multiple times. Then, after freeze-drying for 24 h, continuous MNPs-GOD can be obtained.

[0044] Step 3): Surface modification with chitosan (MNPs-GOD@CS): Weigh 0.40 g of the MNPs-GOD prepared in step 2), ultrasonically disperse it in 50 ml of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), and add 0.15 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.08 g of N-hydroxysuccinimide under mechanical stirring to activate for 120 min. Weigh 0.80 g of chitosan, ultrasonically disperse it in 100 mL of phosphate buffer (Na2HPO4 / NaH2PO4, 0.6 mM, pH = 5.8), and add it to the reaction system after the activation is completed. Stir for 72 h. After the reaction is completed, centrifuge (12,000 rpm, 5 °C) for 10 min for separation, discard the supernatant, and wash with deionized water 4 times. Freeze-dry for 24 h to obtain MNPs-GOD@CS.

[0045] Step 4): Loading of the photodynamic reagent indocyanine green (IR820): Weigh 10 mg of IR820 and ultrasonically disperse it in 10 mL of deionized water; weigh 10 mg of the MNPs-GOD@CS prepared in step 3) and ultrasonically disperse it in 10 mL of deionized water. Add the IR820 dispersion to the MNPs-GOD@CS dispersion and stir mechanically for 12 h. After stirring, centrifuge (12,000 rpm, 5 °C) for 10 min, discard the supernatant, and wash with deionized water 4 times to remove free IR820. Then, rapidly freeze at -80 °C in a cryogenic refrigerator for 6 h, and then freeze-dry for 24 h to obtain MNPs-GOD@CS / IR820.

[0046] The prepared MNPs-GOD@CS / IR820 nanocomposite has good in vitro anti-tumor performance. In the phototoxicity experiment of mouse melanoma cells, the cells are co-incubated with the drug for 12 h, and then irradiated with 808 nm, 0.6 W / cm 2After laser irradiation for 10 min and then incubation for 24 h, the cell viabilities of the blank control, MNPs@CS, MNPs-GOD@CS, IR820, and MNPs-GOD@CS / IR820 groups were 100%, 100.01±4.12%, 91.82±5.28%, 40.60±3.35%, and 7.82±1.17%, respectively. Compared with other groups, the BF cell viability of the MNPs-GOD@CS / IR820 treatment group was the lowest.

Claims

1. A preparation method of a magnetic resonance imaging-guided ferroptosis-photodynamic synergistic therapy nanocomposite, characterized in that It includes the following steps: Step 1): Preparation of citric acid-coated iron oxide nanoparticles: Dissolve 4.3 - 4.5 g of FeCl3 and 2.6 - 2.8 g of FeCl2·4H2O in 80 mL of deionized water, and perform ultrasonic stirring reaction in an N2 atmosphere at 60 - 80 °C. Subsequently, immediately add 15 - 25 mL of ammonia water solution to the obtained reaction mixture, keep warm and continue ultrasonic stirring, add 3 - 5 mL of citric acid aqueous solution, raise the temperature to 85 - 95 °C, and perform reflux reaction; cool the obtained reaction mixture to room temperature, rinse, perform magnetic separation, vacuum dry, and grind to obtain citric acid-coated iron oxide nanoparticles MNPs; Step 2): Immobilization of glucose oxidase: Weigh 0.1 - 0.3 g of citric acid-coated iron oxide nanoparticles and ultrasonically disperse them in 50 mL of phosphate buffer solution. Under stirring, add 0.1 - 0.2 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.07 - 0.09 g of N-hydroxysuccinimide for activation; then add 8 - 12 mg of glucose oxidase, stir and collect. After collection, centrifuge, discard the supernatant, wash, and freeze-dry to obtain MNPs-GOD; Step 3): Surface modification with chitosan: Weigh 0.3 - 0.5 g of MNPs-GOD and ultrasonically disperse it in 50 ml of phosphate buffer solution, and add 0.13 - 0.17 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.06 - 0.10 g of N-hydroxysuccinimide for activation under stirring; weigh 0.7 - 0.9 g of chitosan, ultrasonically disperse it in 100 mL of phosphate buffer solution, and add it to the reaction system after the activation is completed, stir and react. After the reaction is completed, centrifuge and separate, discard the supernatant, wash, and freeze-dry to obtain MNPs-GOD@CS; Step 4): Loading of the photodynamic reagent IR820: Weigh 8 - 12 mg of IR820 and ultrasonically disperse it in 10 mL of deionized water to obtain an IR820 dispersion; weigh 8 - 12 mg of MNPs-GOD@CS and ultrasonically disperse it in 10 mL of deionized water to obtain an MNPs-GOD@CS dispersion; under light-shielded conditions, add the IR820 dispersion to the MNPs-GOD@CS dispersion, stir, centrifuge, discard the supernatant, wash to remove free IR820, rapidly freeze at -85 °C to -75 °C for 5 - 7 h, and freeze-dry to obtain MNPs-GOD@CS / IR820, which is the nanocomposite for magnetic resonance imaging-guided ferroptosis photodynamic synergistic therapy.

2. The preparation method according to claim 1, characterized in that: In Step 1): The volume concentration of the ammonia water solution is 18 - 22%, and the concentration of the citric acid aqueous solution is 0.4 - 0.6 g / mL.

3. The preparation method according to claim 1 or 2, characterized in that: In Step 1): The power of the ultrasonic stirring reaction is 120 - 140 W, the ultrasonic frequency is 15 - 25 KHz, the rotation speed is 800 - 1200 rpm, the ultrasonic stirring reaction time is 20 - 40 min; the time for keeping warm and continuing ultrasonic stirring is 20 - 40 min.

4. The preparation method according to claim 1 or 2, characterized in that: In step 1): The reflux reaction time is 50 - 70 min; the vacuum drying temperature is 50 - 70 °C, and the time is 20 - 30 h.

5. The preparation method according to claim 1, characterized in that: In step 2): The pH of the phosphate buffer solution is 5.6 - 6.0, the power of ultrasonic dispersion is 120 - 140 W, and the ultrasonic frequency is 15 - 25 KHz.

6. The preparation method according to claim 1 or 5, characterized in that: In step 2): The activation time is 110 - 130 min; the stirring and collection time is 10 - 14 h, the centrifugation speed is 11000 - 13000 rpm, the centrifugation temperature is 3 - 7 °C, and the centrifugation time is 5 - 15 min.

7. The preparation method according to claim 1, wherein: In step 3): The pH of the phosphate buffer solution is 5.6 - 6.0, the activation time is 110 - 130 min; the stirring reaction time is 70 - 75 h, the centrifugation speed is 11000 - 13000 rpm, the centrifugation temperature is 3 - 7 °C, and the centrifugation time is 5 - 15 min.

8. The preparation method according to claim 1, characterized in that: In step 4): The stirring speed is 600 - 1000 rpm, the stirring time is 10 - 15 h, the centrifugation speed is 11000 - 13000 rpm, the centrifugation temperature is 3 - 7 °C, the centrifugation time is 5 - 15 min, and the freeze-drying time is 20 - 30 h.