Doped magnetic nanoparticles as well as preparation method and application thereof

Abstract

The invention discloses doped magnetic nanoparticles and a preparation method and application thereof.The doped magnetic nanoparticles take magnetic ferroferric oxide as a base material, a small amount of molybdenum disulfide nanodots are doped, the transverse relaxation efficiency and Fenton reaction activity of magnetic resonance imaging can be remarkably improved, and the magnetic resonance imaging performance is improved. Magnetic resonance signals of a focus area can be greatly improved, a clearer magnetic resonance image with a higher contrast ratio is provided for tumor diagnosis, and meanwhile, the lethality to tumor cells can be improved. The anti-tumor drug is loaded on the doped magnetic nanoparticles, and the bovine serum albumin shell is coated on the doped magnetic nanoparticles, so that the biocompatibility and the lethality to tumor cells can be further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear magnetic resonance imaging, and in particular relates to a doped magnetic nanoparticle and a preparation method and application thereof. Background Art

[0002] Cancer is one of the major public health issues that seriously threatens human health and is one of the top ten causes of death worldwide. Since there are usually no obvious symptoms in the early stages of cancer, many patients are already in the late stages when diagnosed, which greatly increases the difficulty of treatment. Therefore, early diagnosis and treatment of cancer are crucial to reducing cancer mortality. In recent years, with the progress of biomedicine and materials science, iron-based nanomaterials represented by magnetic iron oxide have played an important role in tumor diagnosis and treatment.

[0003] Magnetic iron oxide (MION) has a variety of unique physicochemical properties and biological effects. It exhibits a variety of magnetic response behaviors under external magnetic fields, and can achieve in vivo diagnosis (such as magnetic resonance imaging, ultrasound imaging, photoacoustic imaging, etc.) and treatment (such as magnetic hyperthermia, photothermal therapy, ferroptosis based on Fenton reaction, etc.). MION magnetic resonance contrast agents are favored by scientific researchers due to their excellent T1 / T2 imaging effects and good stability. In addition, iron oxide can effectively trigger ferroptosis of tumor cells and accelerate tumor cell apoptosis. Combined with anti-tumor drugs or other treatment methods, ferroptosis induced by iron oxide-based nanomaterials is expected to break through the bottleneck of the treatment of drug-resistant malignant tumors.

[0004] Therefore, the development of new iron oxide-based nanomaterials for accurate diagnosis and efficient treatment of tumors has important academic significance and clinical value. However, when MION is used as a ferroptosis therapeutic agent, its efficacy is limited by Fe 3+ Fe 2+ The slow conversion rate and insufficient acidity of the tumor environment (TME) are affected.

[0005] In recent studies, transition metal sulfides have been introduced to enhance Fe 3+ Fe 2+ However, these methods all use transition metal sulfides as the matrix material and then load iron ions or iron oxides. Although the Fenton reaction efficiency is significantly improved, their magnetic resonance imaging performance has not been evaluated. Summary of the invention

[0006] Based on the above-mentioned prior art, the present invention provides a doped magnetic nanoparticle and a preparation method and application thereof. The magnetic nanoparticle of the present invention is formed by molybdenum disulfide nanodots doped with nano-iron tetroxide. Compared with simple iron tetroxide nanoparticles, the magnetic nanoparticle can significantly improve the transverse relaxation efficiency and Fenton reaction activity of magnetic resonance imaging, greatly improve the magnetic resonance signal of the lesion area, and effectively kill tumor cells.

[0007] The technical solution adopted to achieve the above-mentioned purpose of the present invention is:

[0008] The invention discloses a doped magnetic nanoparticle, wherein the magnetic nanoparticle is a nanoparticle composed of molybdenum disulfide nanodots doped with nano-ferroferric oxide.

[0009] A method for preparing doped magnetic nanoparticles, characterized by comprising the following steps:

[0010] S1, drying the aqueous dispersion of molybdenum disulfide nanodots to obtain molybdenum disulfide nanodots;

[0011] S2. Add the ferric chloride precursor solution to the molybdenum disulfide nanodots and disperse them evenly, then carry out a solvothermal reaction at 180-220° C., react for 8-12 hours, naturally cool to room temperature, perform magnetic separation, and wash to obtain the doped magnetic nanoparticles.

[0012] Furthermore, the mass ratio of the molybdenum disulfide nanodots to ferric chloride is 0.5-0.8:1.

[0013] The invention discloses a magnetic nanoparticle with good biocompatibility. The nanoparticle has molybdenum disulfide doped ferroferric oxide nanoparticles as the core and bovine serum albumin as the shell.

[0014] A method for preparing magnetic nanoparticles with good biocompatibility comprises the following steps:

[0015] The doped magnetic nanoparticles according to claim 1 are uniformly mixed with a bovine serum albumin aqueous solution, and then dialyzed using a dialysis bag to obtain the magnetic nanoparticles with good biocompatibility.

[0016] A magnetic nanoparticle with drug-carrying function. The nanoparticle has molybdenum disulfide-doped ferroferric oxide nanoparticles as the core, the core is loaded with anti-tumor drugs, and the core is coated with a bovine serum albumin shell.

[0017] Furthermore, the doped magnetic nanoparticles, the magnetic nanoparticles with good biocompatibility, and the magnetic nanoparticles with drug-carrying function all have a spherical nanocluster morphology, and the particle size thereof is 50 to 70 nm.

[0018] Furthermore, the anti-tumor drug is at least one of tamoxifen, doxorubicin, paclitaxel and cisplatin.

[0019] A method for preparing magnetic nanoparticles with drug-carrying function, characterized by comprising the following steps:

[0020] P1, dissolving the antitumor drug in methanol, then adding the doped magnetic nanoparticles according to claim 1, shaking on a shaker at 30-37° C. for 24-30 hours, and magnetically separating to obtain a magnetic solid;

[0021] P2. Evenly mix the magnetic solid and the bovine serum albumin aqueous solution, and then dialyze using a dialysis bag to obtain the magnetic nanoparticles with drug-carrying function.

[0022] Furthermore, the mass ratio of the anti-tumor drug to the doped magnetic nanoparticles is 20-30:1.

[0023] Furthermore, the mass ratio of the doped magnetic nanoparticles to bovine serum albumin is 4-5:1.

[0024] The invention discloses an application of a doped magnetic nanoparticle, a magnetic nanoparticle with good biocompatibility or a magnetic nanoparticle with drug-carrying function in the preparation of a magnetic resonance contrast agent.

[0025] The invention discloses an application of magnetic nanoparticles with drug-carrying function in preparing anti-tumor drugs.

[0026] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0027] 1. The doped magnetic nanoparticles of the present invention use magnetic ferroferric oxide as the matrix material and are doped with a small amount of molybdenum disulfide nanodots, which can significantly improve the transverse relaxation efficiency and Fenton reaction activity of magnetic resonance imaging, greatly improve the magnetic resonance signal of the lesion area, provide higher contrast and clearer magnetic resonance images for tumor diagnosis, and at the same time improve the killing power to tumor cells.

[0028] 2. The synthesis method of the doped magnetic nanoparticles of the present invention is simple, the size is controllable, and the raw materials are cheap and widely available.

[0029] 3. The doped magnetic nanoparticles of the present invention have good biocompatibility and excellent biosafety.

[0030] 4. The present invention loads anti-tumor drugs on doped magnetic nanoparticles and coats them with bovine serum albumin shells, which can further improve biocompatibility and tumor cell killing ability, and at the same time can greatly improve the magnetic resonance signal of the lesion area, providing higher contrast and clearer magnetic resonance images for tumor diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 TEM images of FMB NPs and FMTB NPs prepared in Example 1 and FB NPs prepared in Comparative Example 1.

[0032] Figure 2 This is the hydrated particle size distribution diagram of the magnetic nanoparticles FMTB NPs with drug-carrying function prepared in Example 1.

[0033] Figure 3 This is the element mapping diagram of the magnetic nanoparticles FMTB NPs with drug-carrying function prepared in Example 1.

[0034] Figure 4 T2 of FMTB NPs prepared in Example 1 and FB NPs prepared in Comparative Example 1 1 H-MRI image.

[0035] Figure 5 This is a comparison chart of the lateral relaxation efficiency of FMTB NPs prepared in Example 1 and FB NPs prepared in Comparative Example 1.

[0036] Figure 6 ESR spectra of FMB NPs prepared in Example 1 and FB NPs prepared in Comparative Example 1 under the conditions of pH 6.5 and H2O2.

[0037] Figure 7 Confocal images of 4T1 cells treated with FMB NPs, FMTB NPs prepared in Example 1 and FB NPs prepared in Comparative Example 1.

[0038] Figure 8 Flow cytometric graphs of 4T1 cells treated with FMB NPs, FMTB NPs prepared in Example 1 and FB NPs prepared in Comparative Example 1.

[0039] Fig. 9 T2 MRI images of mice bearing 4T1 subcutaneous tumors under contrast agents prepared with FMTB NPs of Example 1 and FB NPs of Comparative Example 1. DETAILED DESCRIPTION

[0040] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the implementation examples described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0041] The main reagents and materials used in the following examples and comparative examples are described as follows, and other materials not described are also conventional products:

[0042] Ammonium tetrathiomolybdate ((NH4)2MoS4) and anhydrous ferric chloride (FeCl3) were purchased from Shanghai Titan Technology Co., Ltd.; polyvinylpyrrolidone (PVP, M w =10000) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; bovine serum albumin (BSA) was purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.; tamoxifen (TAM) was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; hydrazine hydrate (N2H4·H2O), sodium citrate dihydrate (Na3Cit·2H2O), anhydrous sodium acetate (NaAc), ethylene glycol, diethylene glycol, and methanol were all purchased from Sinopharm Chemical Reagent Co., Ltd.; 4T1 cells were purchased from the Shanghai Cell Bank of the Chinese Academy of Sciences.

[0043] Example 1

[0044] 1. Dissolve 10.4mg (NH4)2MoS4 and 44mg PVP (10KDa) in 40mL methanol, then ultrasonicate for 30 minutes, and add 0.32mL of 50% hydrazine hydrate during the ultrasonication. After the ultrasonication, transfer the obtained mixed solution to a 50mL autoclave, then heat to 120℃, keep the reaction at 120℃ for 3 hours, and cool to room temperature naturally after the reaction. The obtained mixed product is rotary evaporated to remove methanol, 10mL of deionized water is added to the concentrate, and the MoS2 nanodots are redispersed, followed by adding 10 times the equivalent of Na3Cit·2H2O, ultrasonicate for 24 hours, and finally dialyze with an activated 100KDa dialysis bag for 3 days to prepare a 5mg / mL MoS2 nanodot aqueous dispersion for use.

[0045] 2. Dissolve 1.622 g FeCl3 and 3 g Na3Cit·2H2O in a mixed solvent of 40 mL ethylene glycol and 40 mL diethylene glycol, stir at 120°C for 30 minutes, then add 4.1 g NaAc, continue stirring for 1 hour, cool to room temperature for use, and obtain a ferric chloride precursor solution.

[0046] 3. Add 16.2 mL of 5 mg / mL MoS2 nanodots aqueous dispersion into the flask and remove the water by rotary evaporation to obtain molybdenum disulfide nanodots.

[0047] 4. Add the ferric chloride precursor solution to the flask containing molybdenum disulfide nanodots in step 3, disperse by ultrasonication, and then stir for 30 minutes. Transfer the resulting precursor solution to a 100 mL autoclave, heat to 200°C, react at 200°C for 10 hours, and naturally cool to room temperature after the reaction. Magnetic separation and washing are performed to obtain the doped magnetic nanoparticles, which are labeled as FM NPs. The FM NPs are dispersed in ultrapure water and stored at 4°C for later use.

[0048] 5. Take 2 mg of doped magnetic nanoparticles, add 1 mL of 0.5 mg / mL BSA aqueous solution, and dialyze with a 500 KDa dialysis bag for two days to obtain magnetic nanoparticles with good biocompatibility, which are labeled as FMB NPs.

[0049] 6. Weigh 50 mg of TAM and dissolve it in 1 mL of methanol. Then add 2 mg of doped magnetic nanoparticles and shake it at 37 °C for 24 hours. Remove the supernatant by magnetic separation and quickly add 1 mL of 0.5 mg / mL BSA aqueous solution to the magnetic solid. Dialyze it with a 500 KDa dialysis bag for two days to obtain magnetic nanoparticles with drug loading function, which are labeled as FMTB NPs.

[0050] The FMB NPs and FMTB NPs prepared in Example 1 and the FB NPs prepared in Comparative Example 1 were scanned by a transmission electron microscope. The obtained TEM images are shown in FIG. Figure 1 As shown by Figure 1 It can be seen that the FMB NPs and FMTB NPs prepared in this example and the FB NPs prepared in the comparative example all present irregular cluster morphology, and the particle sizes of FMB NPs, FMTB NPs and FB NPs are almost the same, all of which are 50 to 70 nm.

[0051] The magnetic nanoparticles with drug-carrying function prepared in Example 1 were subjected to particle size analysis, and the obtained hydrated particle size distribution diagram is as follows: Figure 2 As shown by Figure 2 It can be seen that the average hydrated particle size of the magnetic nanoparticles (FMTB NPs) with drug-carrying function prepared in this example is 171 nm.

[0052] The element content of the doped magnetic nanoparticles with drug-carrying function prepared in Example 1 was analyzed, and the obtained element mapping diagram is as follows: Figure 3 As shown by Figure 3 It can be seen that the content of iron in the magnetic nanoparticles with drug-carrying function (FMTB NPs) prepared in this example is relatively high, while the content of sulfur and molybdenum is relatively low.

[0053] Comparative Example 1

[0054] 1. Dissolve 1.622 g FeCl3 and 3 g Na3Cit·2H2O in a mixed solvent of 40 mL ethylene glycol and 40 mL diethylene glycol, stir at 120°C for 30 minutes, then add 4.1 g NaAc, continue stirring for 1 hour, cool to room temperature for use, and obtain a ferric chloride precursor solution.

[0055] 2. Transfer the ferric chloride precursor solution to a 100 mL high-pressure reactor, heat it to 200°C, react it at 200°C for 10 hours, and naturally cool it to room temperature after the reaction is completed. Magnetic separation and washing are performed to obtain ferroferric oxide nanoparticles, which are labeled as Fe3O4 NPs. The Fe3O4 NPs are dispersed in ultrapure water and stored at 4°C for future use.

[0056] 3. Take 2 mg of ferroferric oxide nanoparticles, add 1 mL of 0.5 mg / mL BSA aqueous solution, and dialyze with a 500 KDa dialysis bag for two days to obtain magnetic nanoparticles with good biocompatibility, which are marked as FB NPs.

[0057] Experiment 1: Nuclear magnetic properties test experiment of the doped magnetic nanoparticles of the present invention

[0058] Experimental methods:

[0059] 1. The FMTB NPs prepared in Example 1 were completely digested with concentrated nitric acid (mass concentration 68%) to obtain a FMTB NPs mother liquor. The Fe element content of the FMTB NPs mother liquor was determined by ICP-AAS. Then, according to the Fe element content in the FMTB NPs mother liquor, they were diluted with ultrapure water to prepare FMTB NPs solutions with Fe element concentrations of 0.00125, 0.0025, 0.005, 0.01 and 0.02 mM, respectively.

[0060] 2. Transfer each concentration of FMTB NPs test solution to a 10 mm NMR tube and test using a 400M magnetic resonance spectrometer. For the T2 mapping test, the relaxation enhanced rapid acquisition (RARE) sequence was used, with the following parameters: number of scans = 4, repetition time (TR) = 2596 ms, echo time (TE) = 12 ms, scanning field of view (FOV) = 30 mm × 25 mm, slice thickness (SI) = 0.8 mm, matrix size = 256 × 256, sampling time = 5 min 32 s.

[0061] For the transverse relaxation efficiency test, the CPMG sequence was used to test the T2 1 H-NMR performance, sampling time = 3min50s.

[0062] 3. The BSA-modified ferroferric oxide nanoparticles FB NPs prepared in Comparative Example 1 were subjected to the experiment using the method of steps 1-2.

[0063] Experimental results:

[0064] T2 of FMTB NPs solution and FB NPs solution with different concentrations 1 H-MMR Figure 4 As shown by Figure 4 It can be seen that the introduction of MoS2 nanodots significantly enhanced the T2 1 Compared with pure FB NPs, FMTB NPs are more suitable for further use in T2 imaging of 4T1 subcutaneous tumors. 1 H-MRI in vivo imaging.

[0065] The lateral relaxation efficiencies of FMTB NPs solutions and FB NPs solutions with different concentrations are shown in Figure 5 As shown by Figure 5 It can be seen that the transverse relaxation efficiency r2 of FMTB NPs is 121.6 mM -1 ·s -1 , while the lateral relaxation efficiency r2 of FB NPs is 73.0 mM -1 ·s -1 .

[0066] Experiment 2: Fenton reaction performance test experiment of magnetic nanoparticles of the present invention

[0067] Experimental methods:

[0068] 1. Fenton catalytic performance of nanoparticles in solution

[0069] 1.1. Take 100 μL FMB NPs solution (C Fe =0.5mg / mL), add 100μL 20mM H2O2 solution and 200μL 100mM 5,5-dimethyl-1-pyrrolidine-N-oxide (DMPO) solution, mix well and react for 10 minutes, then seal the capillary tube, put it into the sample tube, and then put it into the electron spin resonance spectrometer (ESR) to measure the generation of ·OH. All reagents were diluted and prepared with PBS buffer solution with a pH of 6.5.

[0070] 1.2. Take 100 μL FB NPs (C Fe =0.5 mg / mL), and the test was performed according to the method in step 1.1.

[0071] 2. Fenton reaction performance of nanoparticles in cells

[0072] 2.1. 4T1 cells were placed in RPMI 1640 complete medium (10% fetal bovine serum, 100 U / mL penicillin and 100 μg / mL streptomycin) and routinely subcultured in a cell culture incubator with a CO2 content of 5%, a relative humidity of 90% and a temperature of 37°C. When the cells were in the logarithmic growth phase, they were inoculated into a confocal culture dish and cultured in a cell culture incubator for 24 hours.

[0073] 2.2, PBS solution, FB NPs solution, FMB NPs solution, FMTB NPs solution (C Fe =100 μg / mL) were used to treat the cells cultured in step 2.1 for 12 h, and then 2',7'-dichlorofluorescein diacetate (DCFH-DA) (10.0 μM) was used to stain each treated cell at 37°C in the dark for 30 min, followed by washing three times with PBS, and finally observing the cells with a laser confocal microscope and analyzing the cells with flow cytometry.

[0074] Experimental results:

[0075] At pH 6.5 and in the presence of H2O2, the ESR spectra of FB NPs and FMB NPs are shown in Figure 2. Figure 7 As shown by Figure 7 It can be seen that under the conditions of pH 6.5 and H2O2, obvious ·OH ESR signals were detected in both FB and FMB NPs, which proves that FB and FMB have typical Fenton reaction activity. Importantly, FMB NPs can produce stronger ·OH ESR signals than FB NPs. This result shows that the introduction of MoS2 nanodots significantly improves the Fenton reaction activity of Fe3O4 nanoparticles.

[0076] Confocal images of 4T1 cells treated with PBS, FB, FMB, and FMTB are shown in Figure 2. Figure 7 As shown in Figure 2, since FB and FMB have excellent Fenton reaction activity in solution, we further studied their ROS generation in 4T1 cancer cells. Figure 7 The confocal images shown show that 4T1 cancer cells treated with FB NPs showed weak fluorescence, indicating a relatively low level of ROS generation. Notably, stronger green fluorescence was observed in 4T1 cancer cells treated with FMB NPs, indicating that FMBNPs can generate more ROS within cancer cells. In addition, more intense green fluorescence was observed in 4T1 cancer cells treated with FMTB NPs.

[0077] Flow cytometry images of 4T1 cells treated with PBS, FB, FMB, and FMTB Figure 8 As shown, Figure 8 The results displayed and Figure 7 The results shown are basically consistent, which indicates that the introduction of TAM further enhances the production of intracellular ROS. 1 H MRI experiment

[0078] Experimental methods:

[0079] 1. 4T1 subcutaneous tumor model in Balb / c mice:

[0080] Mouse breast cancer 4T1 cells were placed in RPMI 1640 complete medium and routinely subcultured in a 37°C incubator with a CO2 content of 5% and a relative humidity of 90%. When the cells were in the logarithmic growth phase, they were digested with 0.25% trypsin for 2 minutes, the trypsin was discarded, and 0.0067M PBS, pH = 7.2-7.4, was added to resuspend the 4T1 cells and make the concentration 5×10 6 Each adult female Balb / c mouse was subcutaneously injected with 100 μL of cell suspension at the right back and kept in an SPF animal room for two weeks.

[0081] 2. In vivo subcutaneous tumor mice 1 H MRI experiment:

[0082] 200 μL of FB NPs solution and FMTB NPs solution (FB NPs and FMTB NPs were dispersed in PBS, respectively, and the concentration of Fe element was 3 mg / mL) were injected into the tail vein of the subcutaneous tumor mice with successful modeling in step 1, and the mice were tested using a 9.4T micro-imaging system, and images were collected at 0, 2, 4, 8, 12, 18, and 24 hours, respectively. 1 The H MRI test used the rapid acquisition with relaxation enhancement (RARE) sequence with the following parameters: number of scans = 4, repetition time (TR) = 2596 ms, echo time (TE) = 12 ms, scanning field of view (FOV) = 30 mm × 25 mm, slice thickness (SI) = 0.8 mm, matrix size = 256 × 256, and sampling time = 5 min 32 s.

[0083] Experimental results:

[0084] Magnetic resonance imaging of mice bearing 4T1 subcutaneous tumors at different time points after injection of FB NPs and FMTB NPs solution Fig. 9 As shown by Fig. 9 It can be seen that when FB NPs and FMTB NPs solutions were not injected, the tumor site showed bright signals in the T2 MRI images of tumor-bearing mice. After FB or FMTB NPs solutions were injected into the tail vein of 4T1 subcutaneous tumor mice, it can be seen from T2 MRI that the tumor gradually darkened during the observation process, and the T2 MRI contrast effect of the tumor continued to increase from 0 to 8 hours after injection, and the brightness of the tumor area gradually decreased, and the darkest appeared 8 hours after injection. Importantly, the group injected with FMTB NPs produced a darker T2 MRI signal compared with the FB NPs group, indicating that FMTB NPs have enhanced T2 MRI contrast performance.

Claims

1. A doped magnetic nanoparticle, characterized in that: The magnetic nanoparticles are nanoparticles composed of molybdenum disulfide nanodots doped with nano-ferroferric oxide.

2. A method for preparing doped magnetic nanoparticles according to claim 1, characterized in that The steps include: S1, drying the aqueous dispersion of molybdenum disulfide nanodots to obtain molybdenum disulfide nanodots; S2. Add the ferric chloride precursor solution to the molybdenum disulfide nanodots and disperse them evenly, then carry out a solvothermal reaction at 180-220° C., react for 8-12 hours, naturally cool to room temperature, perform magnetic separation, and wash to obtain the doped magnetic nanoparticles.

3. The method for preparing doped magnetic nanoparticles according to claim 3, characterized in that: The mass ratio of the molybdenum disulfide nanodots to ferric chloride is 0.5-0.8:

1.

4. A magnetic nanoparticle with good biocompatibility, characterized in that: The nanoparticles are composed of molybdenum disulfide-doped ferroferric oxide nanoparticles as the core and bovine serum albumin as the shell.

5. A method for preparing magnetic nanoparticles with good biocompatibility as claimed in claim 4, characterized in that The steps include: The doped magnetic nanoparticles according to claim 1 are uniformly mixed with a bovine serum albumin aqueous solution, and then dialyzed using a dialysis bag to obtain the magnetic nanoparticles with good biocompatibility.

6. A magnetic nanoparticle with drug-carrying function, characterized in that: The nanoparticles are composed of molybdenum disulfide-doped ferroferric oxide nanoparticles as the core, the core is loaded with anti-tumor drugs, and the core is coated with a bovine serum albumin shell.

7. The doped magnetic nanoparticles according to claim 1, the magnetic nanoparticles with good biocompatibility according to claim 4, or the magnetic nanoparticles with drug-carrying function according to claim 6, characterized in that; The doped magnetic nanoparticles, the magnetic nanoparticles with good biocompatibility, and the magnetic nanoparticles with drug-carrying function all have a spherical nanocluster morphology, and the particle diameters thereof are all 50-70 nm.

8. The magnetic nanoparticles with drug-carrying function according to claim 6, characterized in that: The anti-tumor drug is at least one of tamoxifen, doxorubicin, paclitaxel and cisplatin.

9. A method for preparing magnetic nanoparticles with drug-carrying function according to claim 6, characterized in that The steps include: P1, dissolving the antitumor drug in methanol, then adding the doped magnetic nanoparticles according to claim 1, shaking on a shaker at 30-37° C. for 24-30 hours, and magnetically separating to obtain a magnetic solid; P2. Evenly mix the magnetic solid and the bovine serum albumin aqueous solution, and then dialyze using a dialysis bag to obtain the magnetic nanoparticles with drug-carrying function.

10. The method for preparing magnetic nanoparticles with drug-carrying function according to claim 9, characterized in that: The mass ratio of the anti-tumor drug to the doped magnetic nanoparticles is 20-30:

1.

11. The method for preparing the magnetic nanoparticles with good biocompatibility according to claim 4 or the magnetic nanoparticles with drug-carrying function according to claim 6, characterized in that: The mass ratio of the doped magnetic nanoparticles to bovine serum albumin is 4-5:

1.

12. Use of the magnetic nanoparticles according to claim 1, claim 5 or claim 7 in the preparation of a magnetic resonance contrast agent.

13. Use of the magnetic nanoparticles with drug-carrying function as claimed in claim 7 in preparing anti-tumor drugs.

Images