Ferrite nanoparticles as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of biomedical materials, and discloses ferrite nanoparticles as well as a preparation method and application thereof. The preparation method of the ferrite nanoparticles comprises the following steps: S1, mixing a hafnium source, an iron source and triethylene glycol to obtain a mixed solution; s2, heating the mixed solution in an inert atmosphere to obtain a precursor solution; and S3, carrying out segmented heat treatment on the precursor solution, cooling, adding a precipitant, and collecting the precipitate to obtain the ferrite nanoparticles. According to the preparation method of the ferrite nanoparticles, accurate co-doping of hafnium-iron atoms in ferrite crystal lattices is realized; the nano-crystalline grains are controllable in defect, clear in grain boundary, uniform and controllable in size, good in dispersity and adjustable in element doping proportion; the nano-material system constructed by the nano-crystalline grains and albumin is uniform in size and good in biocompatibility; and a key material support is provided for developing a high-performance magnetic hyperthermia-image navigation-drug controlled release integrated nano diagnosis and treatment platform.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, specifically to a ferrite nanoparticle, its preparation method, and its application. Background Technology

[0002] Magnetic Resonance Imaging (MRI), a non-invasive, high-resolution medical imaging technique, relies on the difference in relaxation time (T1 / T2) between tissues to achieve optimal imaging results. Superparamagnetic iron(III) oxide nanoparticles (Fe3O4) have become a commonly used negative contrast agent (signal darkening) in clinical practice due to their ability to significantly shorten the transverse relaxation time (T2) of surrounding water protons. However, traditional Fe3O4 nanoparticles have the following limitations: (1) Traditional Fe3O4 is mainly used as a T2 contrast agent, which can easily lead to negative enhancement of images (signal darkening) and insufficient contrast at low concentrations; while T1 contrast agents (such as gadolinium complexes) can achieve positive enhancement (signal brightening), but there is a risk of gadolinium deposition toxicity; (2) The POD-like activity of Fe3O4 is highly dependent on pH and temperature, and its catalytic efficiency is low in the tumor microenvironment (weakly acidic, low H2O2 concentration), which limits its therapeutic application; (3) Fe3O4 is difficult to meet the needs of integrated diagnosis and treatment at the same time, and needs to be combined with other materials (such as chemotherapy drugs, photothermal agents) to achieve multimodal treatment.

[0003] Therefore, developing a multifunctional ferrite nanomaterial that combines efficient T1 / T2 relaxation properties, self-driven catalytic therapy capabilities, and radiosensitization effects can solve the problems of insufficient contrast in existing MRI contrast agents and the single function of radiosensitizers. It can provide a safe and efficient multimodal diagnostic and treatment platform for promoting the integration of precision diagnosis and treatment of tumors, and has significant social and economic benefits. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide ferrite nanoparticles, their preparation method, and their applications.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing ferrite nanoparticles, comprising the following steps:

[0007] S1. Mix hafnium source, iron source and triethylene glycol to obtain a mixed solution; the molar ratio of hafnium source and iron source is 1:(1-5);

[0008] S2. Under an inert atmosphere, the mixed solution is heated to obtain a precursor solution;

[0009] S3. The precursor solution is subjected to segmented heat treatment, cooled, a precipitant is added, and the precipitate is collected to obtain the ferrite nanoparticles. The segmented heat treatment includes a first heat treatment and a second heat treatment. The first heat treatment is performed by heating to 150℃-200℃ at a rate of 1℃ / min-3℃ / min and holding for 0.5h-1h. The second heat treatment is performed by heating to 250℃-270℃ at a rate of 1℃ / min-3℃ / min and holding for 1.5h-2h.

[0010] This invention discloses a method for preparing ferrite nanoparticles, which centers on the synergistic thermal decomposition-nucleation growth mechanism of iron and hafnium sources. By precisely controlling the chemical reaction kinetics during high-temperature heat treatment, it achieves accurate co-doping of hafnium-iron atoms in the ferrite lattice, allowing hafnium to be uniformly embedded in the ferrite lattice in a substitutional or interstitial manner. This results in nanocrystals with controllable defects and clear grain boundaries. Furthermore, the nanoparticles obtained by this method exhibit uniform and controllable size, good dispersion, and adjustable elemental doping ratios. In addition, the abundant hydroxyl (-OH) and carboxyl (-COOH) functional groups retained on the surface of the ferrite nanoparticles provide active sites for subsequent functional molecule modification via electrostatic adsorption or covalent bonding, significantly improving their colloidal stability and targeted delivery efficiency in the biomedical field. This provides crucial material support for developing a high-performance integrated nanodiagnostic platform combining magnetothermal therapy, image navigation, and controlled drug release.

[0011] In a preferred embodiment of the preparation method of ferrite nanoparticles of the present invention, in step S1, the molar ratio of the hafnium source and the iron source is 1:(3-5); the concentration of the hafnium source in the mixed solution is 0.01mol / L-0.05mol / L; and the concentration of the iron source in the mixed solution is 0.02mol / L-0.1mol / L.

[0012] Preferably, in step S1, the molar ratio of the hafnium source to the iron source is 1:3; the concentration of the hafnium source in the mixed solution is 0.02 mol / L; and the concentration of the iron source in the mixed solution is 0.06 mol / L.

[0013] In a preferred embodiment of the method for preparing ferrite nanoparticles according to the present invention, in step S1, the hafnium source is hafnium acetylacetonate and the iron source is iron acetylacetonate.

[0014] In a preferred embodiment of the method for preparing ferrite nanoparticles according to the present invention, in step S2, the heating temperature is 80℃-100℃ and the heating time is 0.5h-2h.

[0015] In a preferred embodiment of the preparation method of the ferrite nanoparticles of the present invention, in step S3, the precipitant is ethyl acetate.

[0016] In a preferred embodiment of the preparation method of the ferrite nanoparticles of the present invention, the volume ratio of the precipitant to the precursor solution is (8-15):1.

[0017] Preferably, the volume ratio of the precipitant to the precursor solution is 10:1.

[0018] In a preferred embodiment of the preparation method of the ferrite nanoparticles of the present invention, the inert atmosphere is argon.

[0019] In a preferred embodiment of the method for preparing ferrite nanoparticles according to the present invention, the heating temperature is 80℃-100℃ and the heating time is 0.5h-2h.

[0020] Preferably, the heating temperature is 90°C and the heating time is 1 hour.

[0021] In a preferred embodiment of the method for preparing ferrite nanoparticles according to the present invention, the first heat treatment is to heat to 200°C at a rate of 2°C / min and hold for 0.5h; the second heat treatment is to heat to 250°C at a rate of 2°C / min and hold for 1.5h.

[0022] Secondly, the present invention provides ferrite nanoparticles prepared by the preparation method described above.

[0023] In a preferred embodiment of the ferrite nanoparticles of the present invention, the ferrite nanoparticles have a spherical structure and a particle size of 8nm-15nm.

[0024] Thirdly, the present invention provides a ferrite nanomaterial made from the aforementioned ferrite nanoparticles.

[0025] As a preferred embodiment of the ferrite nanomaterial of the present invention, the particle size of the ferrite nanomaterial is 90nm-115nm.

[0026] Fourthly, the present invention provides a method for preparing the ferrite nanomaterial, comprising the following steps:

[0027] S1. Dissolve albumin in water to obtain an albumin aqueous solution;

[0028] S2. Mix the ferrite nanoparticles, ligand, stabilizer and organic solvent to obtain an organic solution;

[0029] S3. Under ultrasonic conditions, the organic solution is added dropwise to the albumin aqueous solution, and the reaction is carried out to obtain the ferrite nanomaterial.

[0030] As a preferred embodiment of the preparation method of the ferrite nanomaterials of the present invention, it includes at least any one of the following (1)-(4):

[0031] (1) The albumin is bovine serum albumin;

[0032] (2) The ligand is 2-methylimidazole;

[0033] (3) The stabilizer is nicotinic acid;

[0034] (4) The organic solvent is ethanol.

[0035] Preferably, the concentration of the albumin aqueous solution is 2 mg / mL to 3 mg / mL.

[0036] In a preferred embodiment of the preparation method of the ferrite nanomaterials of the present invention, the mass ratio of the ferrite nanoparticles, the ligand, and the stabilizer is (2-3):(0.5-1):1.

[0037] Fifthly, the present invention provides the application of the ferrite nanoparticles and the ferrite nanomaterials in acoustic sensitizers, radiotherapy sensitizers, and magnetic resonance imaging contrast agents.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the preparation method of ferrite nanoparticles of the present invention takes the synergistic thermal decomposition-nucleation growth mechanism of iron source and hafnium source as the core. By precisely controlling the chemical reaction kinetic path in the high-temperature heat treatment process, the precise co-doping of hafnium-iron atoms in the ferrite lattice is achieved. High-quality doped ferrite nanoparticles with monodispersity, narrow particle size distribution and high crystallinity are directly synthesized in solution, avoiding the problems of particle agglomeration and grain coarsening caused by high-temperature sintering and other processes. At the same time, it overcomes the defects of low yield of hydrothermal method and poor crystallinity of coprecipitation method, significantly improving material quality and process controllability. Moreover, the nanoparticles obtained by this method have uniform and controllable size, good dispersion and adjustable element doping ratio. Secondly, the ferrite nanoparticles of this invention are rich in hydroxyl (-OH) and carboxyl (-COOH) functional groups on their surface. Ferrite nanomaterials obtained by surface modification with albumin exhibit excellent peroxidase-like activity, catalyzing the oxidation of TMB by H₂O₂ to produce a blue product, enabling tumor microenvironment-responsive colorimetric diagnosis and demonstrating potential for catalytic therapy. Furthermore, under X-ray irradiation, they can significantly enhance the killing efficiency against tumor cells, possessing radiation-sensitizing properties suitable for radiotherapy. Simultaneously, the ferrite nanomaterials of this invention can alter magnetic resonance relaxation time, achieving high-contrast T₂-weighted imaging, demonstrating their potential as a contrast agent for magnetic resonance imaging. In addition, the preparation method of the ferrite nanoparticles and ferrite nanomaterials of this invention significantly simplifies the reaction operation, reduces post-processing steps, shortens the production cycle, improves reaction efficiency, and enhances their colloidal stability and targeted delivery efficiency in the biomedical field, providing key material support for the development of a high-performance integrated nanodiagnostic platform combining magnetothermal therapy, image navigation, and controlled drug release. Attached Figure Description

[0039] Figure 1 This is a transmission electron microscope image of ferrite nanoparticles from Example 1 of the present invention;

[0040] Figure 2 This is an elemental distribution diagram of the ferrite nanoparticles in Example 1 of the present invention;

[0041] Figure 3 This is an X-ray diffraction pattern of ferrite nanoparticles in Example 1 of the present invention;

[0042] Figure 4 The images show the ethanol solutions of ferrite nanoparticles from Examples 1-3 of this invention and the particle size distribution of the ferrite nanomaterials used in Examples 1-3.

[0043] Figure 5 The absorption spectra of different ferrite nanomaterials in Test Example 1 and the absorption spectra of ferrite nanomaterials at different temperatures in Test Example 2 are shown below.

[0044] Figure 6This is the absorbance-concentration curve of ferrite nanomaterials under different substrate concentrations in Test Example 3 of this invention;

[0045] Figure 7 This is a graph showing the vc and 1 / v-1 / c curves of the ferrite nanomaterial in Test Example 4 of this invention.

[0046] Figure 8 This is the absorption spectrum of ferrite nanomaterials under different radiation doses in Test Example 5 of this invention;

[0047] Figure 9 The graph shows the longitudinal relaxation time T1 and transverse relaxation time T2 of the ferrite nanomaterial in Test Example 6 of this invention versus the Fe concentration. Detailed Implementation

[0048] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0049] The following description, in conjunction with specific embodiments, illustrates the practical effects of the present invention.

[0050] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, equipment, etc. used are all commercially available unless otherwise specified.

[0051] Example 1:

[0052] This embodiment prepares ferrite nanoparticles. The preparation method includes the following steps:

[0053] S1. Weigh 0.4 mmol of hafnium acetylacetone to obtain raw material a;

[0054] S2. Weigh 1.2 mmol of acetylacetone iron to obtain raw material b;

[0055] S3. Add raw material a and raw material b to 20 mL of triethylene glycol to obtain solution c;

[0056] S4. Vacuum solution c for 30 minutes to remove water and air, and obtain solution d;

[0057] S5. Argon atmosphere is introduced into solution d, heated to 90℃, and magnetically stirred for 1 hour to obtain solution e;

[0058] S6. Heat solution e to 200℃ at a rate of 2℃ / min, hold for 30min, then heat to 250℃ at the same rate and hold for 1.5h to obtain solution f;

[0059] S7. Wait for solution f to cool to room temperature, add 10 times its volume of ethyl acetate, mix well, centrifuge, discard the supernatant, dissolve the precipitate in ethanol, and repeat the above operation three times to obtain the target sample, which is named Hf. x Fe y O4(1:3).

[0060] (2) Analyze Hf using ICP-AES (Shimadzu). x Fe y The elemental ratios in O4(1:3) nanoparticles showed that the mass ratio of Hf to Fe was 1:1.38 and the molar ratio of Hf to Fe was 1:4.40.

[0061] (3) The prepared Hf was observed using a transmission electron microscope (FEI Tecnai G2 spirit). x Fe y The morphology of O4(1:3) nanoparticles, such as Figure 1 As shown, its microstructure consists of relatively uniform spherical particles, with a particle size of approximately 10 nm.

[0062] (4) Further analysis of the elemental distribution of the nanoparticles, such as... Figure 2 As shown, Hf (green) and Fe (red) elements are significantly enriched in the nanoparticles, proving that the nanoparticles have the expected chemical composition and Hf... x Fe y Successful preparation of O4 (1:3).

[0063] (5) The crystal structure of the nanoparticles was characterized by X-ray diffraction (Rigaku). The test results showed that the peaks at 29°, 35°, 43°, 57° and 63° corresponded to the (220), (311), (400), (333) and (440) diffraction peaks of the standard card PDF#89-4319, respectively. The XRD pattern of the nanoparticles conformed to the spinel ferrite structure and was a face-centered cubic close-packed structure.

[0064] (6) Using a dynamic light scattering instrument (NanoBrook Omni) to study Hf x Fe y Particle size was measured using an ethanol solution of O4 (1:3), such as... Figure 4 As shown on the left, the test results show that its particle size is 9.15±0.25nm.

[0065] Example 2:

[0066] This embodiment prepares ferrite nanoparticles. The preparation method includes the following steps:

[0067] S1. Weigh 0.4 mmol of hafnium acetylacetone to obtain raw material a;

[0068] S2. Weigh 0.4 mmol of acetylacetone iron to obtain raw material b;

[0069] S3. Add raw material a and raw material b to 20 mL of triethylene glycol to obtain solution c;

[0070] S4. Vacuum solution c for 30 minutes to remove water and air, and obtain solution d;

[0071] S5. Argon atmosphere is introduced into solution d, heated to 90℃, and magnetically stirred for 1 hour to obtain solution e;

[0072] S6. Heat solution e to 200℃ at a rate of 2℃ / min, hold for 30min, then heat to 250℃ at the same rate and hold for 1.5h to obtain solution f;

[0073] S7. Wait for solution f to cool to room temperature, add 10 times its volume of ethyl acetate, mix well, centrifuge, discard the supernatant, dissolve the precipitate in ethanol, repeat the above operation three times to obtain the target sample, and name it Hf. x Fe y O4(1:1).

[0074] (2) Analyze Hf using ICP-AES (Shimadzu). x Fe y The elemental ratios in O4(1:3) nanoparticles showed that the mass ratio of Hf to Fe was 1:0.47 and the molar ratio of Hf to Fe was 1:1.50.

[0075] (3) Figure 4 As shown on the left, the test results show that its particle size is 12.38±0.27nm.

[0076] Example 3:

[0077] This embodiment prepares ferrite nanoparticles. The preparation method includes the following steps:

[0078] S1. Weigh 0.4 mmol of hafnium acetylacetone to obtain raw material a;

[0079] S2. Weigh 2 mmol of acetylacetone iron to obtain raw material b;

[0080] S3. Add raw material a and raw material b to 20 mL of triethylene glycol to obtain solution c;

[0081] S4. Vacuum solution c for 30 minutes to remove water and air, and obtain solution d;

[0082] S5. Argon atmosphere is introduced into solution d, heated to 90℃, and magnetically stirred for 1 hour to obtain solution e;

[0083] S6. Heat solution e to 200℃ at a rate of 2℃ / min, hold for 30min, then heat to 250℃ at the same rate and hold for 1.5h to obtain solution f;

[0084] S7. Wait for solution f to cool to room temperature, add 10 times its volume of ethyl acetate, mix well, centrifuge, discard the supernatant, dissolve the precipitate in ethanol, repeat the above operation three times to obtain the target sample, and name it Hf. x Fe y O4(1:5).

[0085] (2) Analyze Hf using ICP-AES (Shimadzu). x Fe y The elemental ratios in O4(1:5) nanoparticles showed that the mass ratio of Hf to Fe was 1:1.63 and the molar ratio of Hf to Fe was 1:5.20.

[0086] (3) Figure 4 As shown on the left, the test results show that its particle size is 9.04±0.37nm.

[0087] Comparative Example 1:

[0088] In this comparative example, hafnium oxide nanoparticles (HfO2) were prepared, and the preparation method was similar to that in Example 1.

[0089] Dissolve 0.6 mmol of hafnium acetylacetonate in 20 mL of triethylene glycol, and use it with Hf. x Fe y O4 (1:3) was heated under the same conditions, cooled, precipitated with ethyl acetate, and finally dissolved in ethanol.

[0090] Comparative Example 2:

[0091] This comparative example prepared ferrite nanoparticles using a microwave method, specifically comprising the following steps:

[0092] 2 mmol of ferric acetylacetone was dissolved completely in 20 mL of triethylene glycol under an inert gas atmosphere and then transferred to a microwave reactor (SINEO). The microwave reaction temperature program was: room temperature - 140 °C (hold for 30 min) - 180 °C (hold for 90 min). After the microwave reaction was completed, ethyl acetate was added, and precipitation was carried out by centrifugation under the same conditions to obtain the precipitate product SPIO (Superparamagnetic Iron Oxide) ferrite nanoparticles, which were then dissolved in ethanol solution for storage.

[0093] Comparative Example 3:

[0094] This comparative example prepared a ferrite nanoparticle. The only difference between the preparation method and Example 1 is that hafnium acetylacetone is replaced with hafnium chloride.

[0095] Comparative Example 4:

[0096] This comparative example prepared a ferrite nanoparticle. The only difference between the preparation method and Example 1 is that ferric acetylacetone is replaced with ferric nitrate.

[0097] Comparative Example 5:

[0098] This comparative example prepared a ferrite nanoparticle. The only difference between the preparation method and Example 1 is that the molar amount of hafnium acetylacetone is 2 mmol.

[0099] Comparative Example 6:

[0100] This comparative example prepared ferrite nanoparticles. The only difference between the preparation method and Example 1 is that the molar amount of iron acetylacetone is 3.2 mmol.

[0101] Application Example 1:

[0102] This application example prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y O4), the preparation method includes the following steps:

[0103] (1) Weigh 12.5 mg bovine serum albumin (BSA) and dissolve it in 5 mL of water to obtain a BSA solution; simultaneously weigh 12.4 mg 2-methylimidazole and 12.5 mg nicotinic acid and dissolve them in 500 μL of Hf x Fe y An ethanol solution of O4 (1:3) (containing 30 mg of nanoparticles) was prepared and mixed thoroughly to obtain an organic phase solution.

[0104] (2) Under ultrasound-assisted conditions, the organic phase solution was added dropwise to the BSA solution, and then shaken on a shaker for 12 hours. Finally, the obtained solution was subjected to rotary evaporation to obtain albumin-modified Hf. x Fe y O4(BSA@Hf x Fe y O4(1:3)).

[0105] like Figure 4 As shown on the right, the dynamic light scattering results indicate that BSA@Hf x Fe y The particle size of the O4(1:3) system is 105.55±1.01nm.

[0106] Application Example 2:

[0107] This application example prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y The only difference between the preparation method and the application example of O4 in Example 1 is that the Hf prepared in Example 2 is used. x Fe y O4 (1:1) replaces Hf x Fe y O4(1:3).

[0108] Application Example 3:

[0109] This application example prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y The only difference between the preparation method and the application example of O4 in Example 1 is that the Hf prepared in Example 3 is used. x Fe y O4 (1:5) replaces Hf x Fe y O4(1:3).

[0110] Application Comparative Example 1:

[0111] This application comparatively prepared a ferrite nanomaterial (albumin-modified HfO2), and the preparation method includes the following steps:

[0112] (1) Weigh 12.5 mg bovine serum albumin (BSA) and dissolve it in 5 mL of water to obtain a BSA solution; at the same time, weigh 12.4 mg 2-methylimidazole and 12.5 mg nicotinic acid and dissolve them in 300 μL of ethanol and mix them evenly with 200 μL of ethanol solution of HfO2 (containing 13 mg of nanoparticles) to obtain an organic phase solution.

[0113] (2) The organic phase solution was added dropwise to the BSA solution under ultrasonic assistance, and then shaken on a shaker for 12 hours. Finally, the obtained solution was evaporated by rotary evaporation to obtain albumin-modified HfO2 (BSA@HfO2).

[0114] Application Comparative Example 2:

[0115] This application comparatively prepared a nanomaterial (albumin-chelated hafnium ion system BSA@Hf), and the preparation method includes the following steps:

[0116] (1) Weigh 10 mg of hafnium chloride (HfCl4) and 12.5 mg of bovine serum albumin (BSA) and dissolve them in 5 mL of water to obtain an aqueous mixed solution; separately weigh 12.4 mg of 2-methylimidazole and 12.5 mg of nicotinic acid and dissolve them together in 500 μL of tetrahydrofuran (THF) to obtain an organic phase solution;

[0117] (2) Under ultrasonic assistance, the organic phase solution was added to the aqueous mixed solution and shaken on a shaker for 12 hours. Finally, the residual THF was removed by rotary evaporation of the obtained solution and the albumin chelated hafnium ion system BSA@Hf was obtained by dialysis in water.

[0118] Application Comparative Example 3:

[0119] This application comparatively prepared a ferrite nanomaterial (albumin-modified SPIO), and the preparation method includes the following steps:

[0120] (1) Weigh 12.5 mg bovine serum albumin (BSA) and dissolve it in 5 mL of water to obtain a BSA solution; at the same time, weigh 12.4 mg 2-methylimidazole and 12.5 mg nicotinic acid and dissolve them in 500 μL of SPIO ethanol solution (containing 30 mg of nanoparticles) and mix them evenly to obtain an organic phase solution;

[0121] (2) The organic phase solution was added dropwise to the BSA solution under ultrasonic assistance, and then shaken on a shaker for 12 hours. Finally, the obtained solution was evaporated by rotary evaporation to obtain albumin-modified SPIO (BSA@SPIO).

[0122] Application Comparative Example 4:

[0123] This application comparatively prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y The only difference between the preparation method and application of Comparative Example 3 is that Hf prepared using Comparative Example 3 is used. x Fe y O4 replaces SPIO.

[0124] Application Comparative Example 5:

[0125] This application comparatively prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y The only difference between the preparation method and application of Comparative Example 3 is that Hf prepared in Comparative Example 4 is used instead of O4. x Fe y O4 replaces SPIO.

[0126] Application Comparative Example 6:

[0127] This application comparatively prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y The only difference between the preparation method and application of O4 in Comparative Example 3 is that Hf prepared in Comparative Example 5 is used. x Fe y O4 replaces SPIO.

[0128] Application Comparative Example 7:

[0129] This application comparatively prepared a ferrite nanomaterial (albumin-modified Hf). x Fe y The only difference between the preparation method and application of O4 in Comparative Example 3 is that Hf prepared in Comparative Example 6 is used. x Fe y O4 replaces SPIO.

[0130] Test Example 1: POD Enzyme Activity Test

[0131] To test the POD enzyme activity of the obtained nanomaterials, the nanomaterials were used to catalyze the generation of free radicals from H2O2, which caused TMB oxidation and a color change. The enzyme activity of the material was detected by the change in absorbance before and after the reaction.

[0132] The ferrite nanomaterials of the application examples and comparative examples were dissolved in water to prepare a solution with a metal concentration of 3 mM for performance testing.

[0133] Experimental methods:

[0134] Experimental group 1 (BSA@Hf) x Fe y O4 (1:3): 400 μL water, 50 μL H2O2 solution (100 mM), 20 μL TMB solution (1%, 32.24 mM) and 30 μL BSA@Hf x Fe y After the O4 (1:3) solution was mixed evenly, the system volume was controlled at 500 μL, and the reaction was carried out at 25 °C for 15 min.

[0135] Experimental Group 2 (BSA@HfO2): 400 μL of water, 50 μL of H2O2 solution (100 mM), 20 μL of TMB solution (1%, 32.24 mM) and 30 μL of BSA@HfO2 solution were mixed evenly and the system volume was controlled to be 500 μL. The reaction was carried out under the same conditions.

[0136] Experimental Group 3 (BSA@Hf): 400 μL of water, 50 μL of H2O2 solution (100 mM), 20 μL of TMB solution (1%, 32.24 mM) and 30 μL of BSA@Hf solution were mixed evenly and the system volume was controlled to be 500 μL. The reaction was carried out under the same conditions.

[0137] Control group 1: 430 μL of water reacted with 50 μL of H2O2 solution (100 mM) and 20 μL of TMB solution (1%, 32.24 mM) under the same conditions;

[0138] Control group 2 (Contro2): 480 μL of water and 20 μL of TMB solution (1%, 32.24 mM) were reacted under the same conditions;

[0139] Control group 3 (Contro3): 450 μL of water and 50 μL of H2O2 solution (100 mM) were reacted under the same conditions.

[0140] After the reaction is complete, the absorption spectrum of the reaction system in the range of 800nm-400nm is measured to determine the absorption peak position and to verify whether the sample has the ability to catalyze H2O2.

[0141] like Figure 5 As shown in a, add BSA@Hf x Fe y After the reaction of the O4 (1:3) system was completed, the solution turned blue and showed an absorption peak at 652 nm with an absorbance greater than 0.8, demonstrating its excellent catalytic ability, and compared with albumin-modified Hf... 4+ The two materials, one light blue and the other light blue (HfO2), have better catalytic activity. The absorbance of HfO2 is about 0.2 and the absorbance of HfO2 is about 0.1.

[0142] Test Example 2: Effect of Temperature on the Catalytic Activity of Materials

[0143] Experimental method: 420 μL of water, 50 μL of H2O2 solution (100 mM), 10 μL of TMB solution (1%, 32.24 mM) and 20 μL of BSA@Hf were added. x Fe y The O4 (1:3) solution was mixed evenly and reacted for 10 min at different temperatures (25℃, 30℃, 35℃, 40℃, 45℃, 55℃, 60℃, 65℃, 70℃), and the absorbance at 652 nm was measured.

[0144] like Figure 5 As shown in b, BSA@Hf x Fe y The optimal reaction temperature for O4 (1:3) material is 55℃.

[0145] Test Example 3: Effect of Substrate Concentration on Catalytic Activity of Materials

[0146] Experimental methods:

[0147] (a) Experimental group: 400 μL of water, 50 μL of H2O2 solution (50 μM, 100 μM, 200 μM, 300 μM, 500 μM), 20 μL of TMB solution (1%, 32.24 mM) and 30 μL of BSA@Hf x Fe y Mix the O4 solutions (in different proportions) thoroughly and react at room temperature for 20 minutes.

[0148] Control group:

[0149] Mix 400 μL of water, 50 μL of H2O2 solution (50 μM, 100 μM, 200 μM, 300 μM, 500 μM), 20 μL of TMB solution (1%, 32.24 mM), and 30 μL of the solutions from Comparative Example 1 (BSA@HfO2), Comparative Example 3 (BSA@SPIO), Comparative Example 4, Comparative Example 5, Comparative Example 6, or Comparative Example 7 thoroughly and react at room temperature for 20 min.

[0150] (b) Experimental group: 400 μL of water, 50 μL of H2O2 solution (100 mM), 20 μL of TMB solution (0.2 mM, 0.5 mM, 0.7 mM, 1 mM, 1.5 mM) and 30 μL of BSA@Hf x Fe y Mix the O4 (different proportions) solutions thoroughly and react at 50℃ for 20 minutes.

[0151] Control group:

[0152] Mix 400 μL of water, 50 μL of H2O2 solution (100 mM), 20 μL of TMB solution (0.1 mM, 0.2 mM, 0.5 mM, 0.7 mM, 1 mM) and 30 μL of Comparative Example 1 (BSA@HfO2) solution thoroughly and react at 50 °C for 20 min.

[0153] Mix 400 μL of water, 50 μL of H2O2 solution (100 mM), 20 μL of TMB solution (0.25 mM, 0.5 mM, 0.75 mM, 1 mM, 1.5 mM), and 30 μL of the solution from Comparative Example 3 (BSA@SPIO), Comparative Example 4, Comparative Example 5, Comparative Example 6, or Comparative Example 7 thoroughly and react at 50 °C for 20 min.

[0154] like Figure 6As shown, when the concentrations of the two reactants change, the absorbance after the reaction also changes linearly, further proving the validity of the BSA@Hf assay in this application. x Fe y The catalytic ability of O4 was compared, and the slope of the fitted straight line can be used to compare the catalytic performance of the two systems. Compared to BSA@HfO2, BSA@Hf x Fe y The slope of O4 is significantly improved, indicating a more sensitive response to changes in substrate concentration and exhibiting stronger catalytic activity, particularly with different proportions of BSA@Hf. x Fe y O4 and BSA@SPIO showed similar catalytic activities with slopes of the fitted lines; compared with other application comparisons, the application examples also exhibited superior catalytic activity.

[0155] Test Example 4: Steady-state kinetics test of catalytic reaction in materials

[0156] Experimental methods:

[0157] (a) After mixing 400 μL of water, 50 μL of H2O2 solution (different concentrations), 20 μL of TMB solution (1%, 32.24 mM) and 30 μL of sample solution, the absorbance of the reaction system was immediately detected over time, and the final concentration of H2O2 solution was controlled within the range of 0.1 mM to 10 mM.

[0158] (b) The obtained data curves were fitted using the Michaelis-Menten equations to plot vc and 1 / v-1 / c curves, and the relevant dynamic parameters K were calculated. m and V max K m Vmax represents the substrate concentration at which the enzyme-catalyzed reaction rate is half of the maximum enzyme-catalyzed reaction rate, reflecting the enzyme's affinity for the substrate; Vmax measures the rate of enzyme catalysis.

[0159] like Figure 7 As shown, BSA@HfO2, BSA@Hf x Fe y O4 (Hf:Fe in different proportions), BSA@SPIO and other comparative examples of the Michaelis constant K m The maximum reaction rates V were 0.92 mM, 0.88 mM (1:1), 1 mM (1:3), 1 mM (1:5), 0.18 mM, 0.07 mM (HfCl4), 0.16 mM (FeNO3), 0.16 mM (5:3), and 0.17 mM (1:8), respectively. max They are 3.20×10 -9M / s, 5.88×10 -8 M / s (1:1), 7.14×10 -8 M / s (1:3), 6.67×10 -8 M / s (1:5), 9.09×10 -8 M / s, 3.33×10 -8 M / s(HfCl4), 4×10 -8 M / s(FeNO3), 2.33×10 -8 M / s (5:3), 5.56×10 -8 M / s (1:8). Different ratios of BSA@Hf x Fe y The Michaelis constants Km of O4 and BSA@HfO2 are not significantly different, indicating similar affinity for the substrate H2O2. BSA@SPIO and other comparative applications also show high affinity for their substrates. x Fe y The maximum reaction rate V in O4 is achieved when Hf:Fe = 1:3. max The catalytic reaction rate is the highest, far exceeding that of BSA@HfO2, meaning its catalytic reaction rate is higher than that of BSA@HfO2. BSA@SPIO also exhibits a high catalytic reaction rate. Compared to other application comparisons, the catalytic reaction rate of the application examples is also higher.

[0160] Test Example 5: Catalytic Ability Test of Materials under Radiation

[0161] Experimental method: 470 μL of water, 10 μL of H2O2 solution (1M), 10 μL of TMB solution (1%, 32.24 mM) and 10 μL of LBSA@Hf were added. x Fe y The O4 (1:3) solution or BSA@SPIO solution was mixed thoroughly and reacted for 5 min under irradiation at doses of 0, 1, and 3 Gy. The UV absorption spectrum of the reaction system was then measured after dilution by the same factor.

[0162] like Figure 8 As shown, under radiation conditions, a more pronounced color change occurs in a short time compared to the non-radiation group. The absorption peak at 652 nm also demonstrates that with increasing radiation dose, BSA@Hf x Fe y The enhanced catalytic ability of O4 (1:3) indicates the generation of more free radicals, which also explains the positive effect of BSA@Hf. x Fe yThe O4(1:3) system exhibits radiosensitizing properties; however, the experimental results for BSA@SPIO show that its final absorbance does not change with the radiation dose, indicating that it does not possess radiosensitizing properties, thus demonstrating the influence of Hf doping on the radiation absorption properties of ferrite materials.

[0163] Test Example 6: Testing the Magnetic Resonance Imaging Capability of Materials

[0164] Experimental method: BSA@Hf x Fe y The O4 (1:3) system was diluted with deionized water to prepare solutions with a certain concentration gradient, i.e., the final Fe concentrations were 1 mM, 0.5 mM, 0.25 mM, 0.1 mM, and 0.05 mM. 200 μL of each concentration solution was taken, and the longitudinal relaxation time of each concentration was measured using a 1.5T nuclear magnetic resonance system (Shanghai Huantong Educational Equipment Co., Ltd.). The relaxation rate was calculated by fitting the relationship between relaxation time and Fe concentration.

[0165] like Figure 9 As shown, with increasing iron concentration, there is a clear linear relationship between the longitudinal relaxation time T1 and the transverse relaxation time T2 and the Fe concentration, proving that the nanosystem can successfully accelerate the relaxation process and achieve nuclear magnetic resonance imaging; and the transverse relaxation rate R2 is 109.28 mM. -1 ·s -1 The longitudinal relaxation rate R1 is 3.1573 mM. -1 ·s -1 The imaging performance is close to that of clinically used Gd contrast agents, showing good T1 imaging performance; the ratio of R2 to R1 is R2 / R1 = 34.61 > 20, indicating excellent T2 imaging capability. Therefore, the T1-T2 dual-modal effect of this nanosystem is beneficial for precise monitoring of lesions through in vivo MRI.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing ferrite nanoparticles, characterized in that, Includes the following steps: S1. Mix hafnium source, iron source and triethylene glycol to obtain a mixed solution; the molar ratio of hafnium source and iron source is 1:(1-5); S2. Under an inert atmosphere, the mixed solution is heated to obtain a precursor solution; S3. The precursor solution is subjected to segmented heat treatment, cooled, a precipitant is added, and the precipitate is collected to obtain the ferrite nanoparticles. The segmented heat treatment includes a first heat treatment and a second heat treatment. The first heat treatment is performed by heating to 150℃-200℃ at a rate of 1℃ / min-3℃ / min and holding for 0.5h-1h. The second heat treatment is performed by heating to 250℃-270℃ at a rate of 1℃ / min-3℃ / min and holding for 1.5h-2h.

2. The method for preparing ferrite nanoparticles as described in claim 1, characterized in that, In step S1, the molar ratio of the hafnium source to the iron source is 1:(3-5); the concentration of the hafnium source in the mixed solution is 0.01mol / L-0.05mol / L; and the concentration of the iron source in the mixed solution is 0.02mol / L-0.1mol / L.

3. The method for preparing ferrite nanoparticles as described in claim 2, characterized in that, In step S1, the molar ratio of the hafnium source to the iron source is 1:3; the concentration of the hafnium source in the mixed solution is 0.02 mol / L; and the concentration of the iron source in the mixed solution is 0.06 mol / L.

4. The method for preparing ferrite nanoparticles as described in claim 1, characterized in that, In step S1, the hafnium source is hafnium acetylacetonate; the iron source is iron acetylacetonate.

5. The method for preparing ferrite nanoparticles as described in claim 1, characterized in that, In step S2, the heating temperature is 80℃-100℃ and the heating time is 0.5h-2h.

6. The method for preparing ferrite nanoparticles as described in claim 1, characterized in that, In step S3, the precipitant is ethyl acetate.

7. Ferrite nanoparticles prepared by the preparation method according to any one of claims 1-6.

8. A ferrite nanomaterial, characterized in that, It is made from the ferrite nanoparticles as described in claim 7.

9. The method for preparing the ferrite nanomaterial according to claim 8, characterized in that, Includes the following steps: S1. Dissolve albumin in water to obtain an albumin aqueous solution; S2. Mix the ferrite nanoparticles, ligand, stabilizer and solvent to obtain an organic solution; S3. Under ultrasonic conditions, the organic solution is added dropwise to the albumin aqueous solution, and the reaction is carried out to obtain the ferrite nanomaterial.

10. The application of the ferrite nanoparticles of claim 7 and the ferrite nanomaterials of claim 9 in acoustic sensitizers, radiotherapy sensitizers, and magnetic resonance imaging contrast agents.

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