Enzyme heuristic magnetic nanoprobe as well as preparation method and application thereof

Abstract

The invention provides an enzyme heuristic magnetic nanoprobe and a preparation method and application thereof.The preparation method comprises the steps that gold tetrachlorate trihydrate and gadolinium acetylacetonate hydrate are dissolved in a mixed solvent of tetrahydronaphthalene and oleylamine, a reducing agent is rapidly injected under the inert atmosphere condition of 4-50 DEG C, a reaction is conducted for 30-60 min, a first non-polar solvent is used for washing, precipitation and centrifugation, and an enzyme heuristic magnetic nanoprobe is obtained; the oil-phase enzyme heuristic magnetic nanoparticles are obtained; carrying out surface hydrophilic modification on the obtained oil-phase enzyme heuristic magnetic nanoparticles in a mixed solvent system consisting of polar solvents by using hydrophilic molecules through a ligand exchange method to obtain aqueous-phase enzyme heuristic magnetic nanoparticles; the preparation method comprises the following steps: carrying out chemical amide connection reaction on aqueous-phase enzyme heuristic magnetic nanoparticles, and coupling the aqueous-phase enzyme heuristic magnetic nanoparticles with a high-specificity ligand to finish surface targeted modification, thereby obtaining the enzyme heuristic magnetic nanoprobe. According to the invention, efficient chemical exchange of water protons can be promoted, so that the magnetic resonance T1 imaging effect is obviously enhanced.

Description

Technical Field

[0001] This invention relates to the field of bioimaging probe technology, specifically to an enzyme-inspired magnetic nanoprobe, its preparation method, and its application. Background Technology

[0002] The ultimate goal of in vivo diagnostic imaging is to accurately identify microscopic lesions to guide clinical decision-making. Magnetic resonance imaging (MRI), with its advantages such as high spatial resolution and no ionizing radiation, has become an indispensable tool in modern medical diagnosis. With the development of ultra-high field imaging (≥ 7 T) technology, the signal-to-noise ratio and resolution of MRI images have been significantly improved, making the detection of lesions at the hundred-micrometer level possible. However, the full utilization of MRI performance largely depends on contrast agents, which enhance the imaging signal by enhancing water proton relaxation. Currently, contrast agents based on longitudinal relaxation (T1) face a major bottleneck: their relaxation rate decreases sharply with increasing field strength, which severely weakens their imaging performance under ultra-high fields, limiting their application.

[0003] According to classical SBM theory, the T1 relaxation efficiency depends on the dynamic interaction between paramagnetic centers and water protons. Current contrast agents primarily rely on the passive relaxation of water molecules. The inherent inefficiency of this mechanism limits the improvement of the relaxation rate, and a high relaxation rate requires the formation of an adsorption-desorption equilibrium at the paramagnetic centers to ensure effective water molecule exchange. Therefore, the key to achieving a breakthrough in relaxation rate lies in developing novel contrast agents with the ability to actively capture water molecules and possess catalytic exchange kinetics, enabling them to achieve strong and reversible water proton interactions at high-density relaxation sites.

[0004] Inspired by the catalytic mechanisms of enzymes in nature—enzymes promote efficient substrate binding and conversion by manipulating the spatial and electronic environment of their active sites at the quantum scale—we propose a biomimetic magnetic nanoprobe design strategy. At the quantum level, surface strain can modulate the electronic structure of metal atoms, inducing electron recombination during enzyme activation, thereby optimizing paramagnetic centers to improve water molecule exchange efficiency. Quantum strain engineering achieved through lattice distortion (such as twin boundaries or high-index crystal planes) can precisely control the electronic activity of contrast agents, improve the performance of relaxation sites, and coordinate water exchange kinetics. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an enzyme-inspired magnetic nanoprobe, its preparation method, and its applications. Inspired by the principles of spatial and electronic regulation of active sites in the efficient catalytic mechanism of enzymes, the relaxation ability of magnetic nanoprobes can be significantly improved by precisely controlling key electronic properties such as charge distribution and electron transfer kinetics, while simultaneously optimizing spatial density and coordination structure.

[0006] The method for preparing enzyme-inspired magnetic nanoprobes according to the present invention includes the following steps: Step S1: Dissolve the gold source compound and the gadolinium source compound in an oil-phase mixed solvent, inject a reducing agent and react under an inert atmosphere, wash the precipitate with a first non-polar solvent and centrifuge to obtain oil-phase enzyme-inspired magnetic nanoparticles. Step S2: The oil-phase enzyme-inspired magnetic nanoparticles are surface-modified with hydrophilic molecules in a suitable solvent system to obtain aqueous enzyme-inspired magnetic nanoparticles; the suitable solvent system is a mixture of a first polar solvent and a second non-polar solvent. Step S3: The aqueous enzyme-inspired magnetic nanoparticles are coupled with a highly specific ligand via a chemical amide linkage reaction to complete surface targeting modification, thereby obtaining the enzyme-inspired magnetic nanoprobe.

[0007] Preferably, in step S1, the gold source compound is gold tetrachloride trihydrate, and the gadolinium source compound is gadolinium acetylacetonate hydrate; The oil phase mixed solvent is a mixture of tetrahydronaphthalene and oleylamine; The first nonpolar solvent is selected from one or more of anhydrous ethanol, acetone, methanol, isopropanol and acetic acid.

[0008] Preferably, in step S1, the reducing agent is selected from one or more of tetrabutylamine borane, trisec-butyllithium borohydride, dimethylamine borane, polyols and long-chain primary amines; The reaction is carried out at a temperature of 4-50°C for 30-60 minutes. The feeding ratio of each component in the gold source compound, gadolinium source compound, and oil phase mixed solvent to the reducing agent is 0~1 mmol: 0~1 mmol: 1~10 mL: 1~10 mL: 0~1 mmol.

[0009] Preferably, in step S2, a ligand exchange method is used, specifically by adding the oil-phase enzyme-inspired magnetic nanoparticles to the suitable solvent system, then adding hydrophilic molecules, and reacting at room temperature to obtain aqueous-phase enzyme-inspired magnetic nanoparticles.

[0010] Preferably, the first polar solvent is one or more of o-dichlorobenzene, chloroform, n-hexane, cyclohexane, and toluene; The second nonpolar solvent is one or more of acetone, ethanol, N,N-dimethylformamide, and dimethyl sulfoxide; The hydrophilic molecule is one or more of polyethylene glycol, polyvinylpyrrolidone, polydopamine, cysteine, mercaptosuccinic acid, and mercaptopropionic acid.

[0011] Preferably, in step S3, the chemical amide linkage reaction specifically includes: adding aqueous enzyme-inspired magnetic nanoparticles, a catalyst, and the highly specific ligand to a second polar solvent, reacting at room temperature, and then purifying to obtain the enzyme-inspired magnetic nanoprobe.

[0012] Preferably, the highly specific ligand is one or more of folic acid, an arginine-glycine-aspartic acid sequence, an aptamer, and a CREKA peptide; The highly specific ligands correspond to specific biological factors that are highly expressed in major diseases such as tumors.

[0013] Preferably, the second polar solvent is one or more of 2-(N-morpholine)ethanesulfonic acid buffer, phosphate buffer, deionized water, dimethyl sulfoxide, and N,N-dimethylformamide.

[0014] The enzyme-inspired magnetic nanoprobe prepared by the preparation method described in this invention.

[0015] The application of the enzyme-inspired magnetic nanoprobe provided by this invention in the preparation of contrast agents for early diagnosis of major diseases in magnetic resonance imaging.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides an enzyme-inspired magnetic nanoparticle that significantly improves magnetic resonance T1 imaging performance by controlling its electronic structure through surface strain engineering. Specifically, by precisely controlling the stoichiometric ratio of low-packing-energy gold atoms to high-spin-magnetic-moment gadolinium atoms, a controllable multitwin structure is achieved. This structure induces lattice distortion, which in turn induces surface strain, resulting in a rearrangement of the electronic structure on the crystal surface and enhancing the electronic induction effect of surface Gd atoms on water molecules. This enables the active capture of water molecules and coordinates efficient chemical exchange with water protons, thereby establishing an efficient proton-electron relaxation coupling path. On the other hand, the twin boundaries in the multitwin structure have a strong pinning effect on the magnetic domain walls, hindering the growth of magnetic domains along the external magnetic field; simultaneously, this structure induces significant magnetic anisotropy, significantly reducing the magnetic moment vector sum, thereby generating ultra-low magnetization and effectively suppressing the T2 decay effect. Therefore, the above mechanisms work synergistically to significantly enhance the T1 imaging capability of this enzyme-inspired magnetic nanoprobe under ultra-high fields. 2. In the preparation method of the enzyme-inspired magnetic nanoprobe provided by this invention, the ligand exchange reaction is mainly used to transform the oil-phase enzyme-inspired magnetic nanoparticles into the corresponding aqueous-phase enzyme-inspired magnetic nanoparticles, thereby improving biocompatibility and enabling the high-spin magnetic moment Gd ions on its surface to effectively relax with water molecules. In addition, the materials prepared in the entire preparation method have good biocompatibility and extremely high stability, which lays a certain foundation and advantage for their application in contrast agents. 3. In the application of the enzyme-inspired magnetic nanoprobe provided by the present invention, the surface modification of the enzyme-inspired magnetic nanoprobe can enable it to be highly specific to accumulate in small lesion sites, minimizing the toxic side effects on other normal tissues. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 Transmission electron microscopy image of the oil-phase enzyme-inspired magnetic nanoparticles in Example 1. Figure 2 Transmission electron microscopy image of the oil-phase enzyme-inspired magnetic nanoparticles in Example 2; Figure 3 Transmission electron microscopy image of the oil-phase enzyme-inspired magnetic nanoparticles in Example 3. Figure 4 Transmission electron microscopy image of the aqueous enzyme-inspired magnetic nanoparticles in Example 4. Figure 5 The dynamic light scattering particle size distribution of the aqueous enzyme-inspired magnetic nanoparticles in Example 4 is shown. Figure 6 The hysteresis regression curve of the aqueous enzyme-inspired magnetic particles in Example 4 is shown. Figure 7 Transmission electron microscopy image of the aqueous enzyme-inspired magnetic nanoparticles in Example 5. Figure 8 The dynamic light scattering particle size distribution of aqueous enzyme-inspired magnetic nanoparticles in Example 5 is shown. Figure 9 Transmission electron microscopy image of the aqueous enzyme-inspired magnetic nanoparticles in Example 6. Figure 10 The dynamic light scattering particle size distribution of the aqueous enzyme-inspired magnetic nanoparticles in Example 6 is shown. Figure 11 This is a transmission electron microscope image of the enzyme-inspired magnetic nanoprobe in Example 7. Figure 12 The dynamic light scattering particle size distribution of the enzyme-inspired magnetic nanoprobe in Example 7 is shown. Figure 13 The image shows the magnetic resonance imaging of the enzyme-inspired magnetic nanoprobe in Example 7. Figure 14 The relaxation time-concentration plot of the enzyme-inspired magnetic nanoprobe in Example 7; Figure 15 This is an ultra-high field magnetic resonance imaging image of random metastatic lesions throughout the body in an application example. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0019] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be for both fixing and circuit connection purposes.

[0020] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] This invention first provides an enzyme-inspired magnetic nanoprobe and its application in the preparation of magnetic resonance imaging contrast agents. The enzyme-inspired magnetic nanoprobe, prepared under certain conditions, can identify tiny lesion sites with high specificity, play a role in enhancing imaging sensitivity in magnetic resonance imaging, and can produce significant contrast with surrounding normal tissues.

[0023] The present invention will be further explained in detail below with reference to embodiments: Example 1 This embodiment provides the synthesis of oil-phase enzyme-inspired magnetic nanoparticles.

[0024] 0.127 mmol gold tetrachloride trihydrate and 0.063 mmol gadolinium acetylacetonate hydrate were dissolved in a mixed solution of tetrahydronaphthalene and oleylamine. 0.25 mmol tetrabutylamine borane was rapidly injected under an inert atmosphere at 45 °C and the reaction was continued for 60 minutes. After the reaction was completed, the precipitate was washed with acetone by centrifugation to obtain oil-phase enzyme-inspired magnetic nanoparticles.

[0025] The morphology of the prepared oil-phase enzyme-inspired magnetic nanoparticles was characterized by transmission electron microscopy, such as... Figure 1 As shown.

[0026] Example 2 This embodiment provides the synthesis of oil-phase enzyme-inspired magnetic nanoparticles.

[0027] 0.127 mmol gold tetrachloride trihydrate and 0.032 mmol gadolinium acetylacetonate hydrate were dissolved in a mixed solution of tetrahydronaphthalene and oleylamine. 0.25 mmol tetrabutylamine borane was rapidly injected under an inert atmosphere at 45 °C and the reaction was continued for 60 minutes. After the reaction was completed, the precipitate was washed by centrifugation with acetone to obtain oil-phase enzyme-inspired magnetic nanoparticles.

[0028] The morphology of the prepared oil-phase enzyme-inspired magnetic nanoparticles was characterized by transmission electron microscopy, such as... Figure 2 As shown.

[0029] Example 3 This embodiment provides the synthesis of oil-phase enzyme-inspired magnetic nanoparticles.

[0030] 0.127 mmol gold tetrachloride trihydrate and 0.024 mmol gadolinium acetylacetonate hydrate were dissolved in a mixed solution of tetrahydronaphthalene and oleylamine. 0.25 mmol tetrabutylamine borane was rapidly injected under an inert atmosphere at 45 °C and the reaction was continued for 60 minutes. After the reaction was completed, the precipitate was washed by centrifugation with acetone to obtain oil-phase enzyme-inspired magnetic nanoparticles.

[0031] The morphology of the prepared oil-phase enzyme-inspired magnetic nanoparticles was characterized by transmission electron microscopy, such as... Figure 3 As shown.

[0032] Example 4 This embodiment provides the synthesis of aqueous enzyme-inspired magnetic nanoparticles.

[0033] First, dicarboxylated modified polyethylene glycol (120 mg), mercapto-polyethylene glycol (60 mg), N-hydroxysuccinimide (12 mg), N,N'-dicyclohexylcarbodiimide (18 mg), dopamine hydrochloride (8 mg), and sodium carbonate (60 mg) were dissolved in a chloroform / N,N-dimethylformamide mixed solvent (12 / 6 mL) and stirred at 45 °C for 2 hours. Then, oil-phase enzyme-inspired magnetic particles (5 mg) were added, and the reaction was carried out at 25 °C for 12 hours. After the reaction, the particles were precipitated with n-hexane and centrifuged, followed by dialysis purification and concentration to obtain aqueous-phase enzyme-inspired magnetic nanoparticles. These aqueous-phase enzyme-inspired magnetic nanoparticles exhibit significant biocompatibility, a high abundance of gadolinium active sites on their surface, and a strong electronic induction effect on water molecules, enabling active and efficient relaxation.

[0034] The morphology of the prepared aqueous enzyme-inspired magnetic nanoparticles was characterized by transmission electron microscopy, such as... Figure 4 As shown.

[0035] The hydrodynamic particle size was tested using dynamic light scattering, and the results are as follows: Figure 5 As shown.

[0036] The magnetization intensity was tested using a magnetic performance measurement system, and the results are as follows: Figure 6 As shown.

[0037] Example 5 This embodiment provides the synthesis of aqueous enzyme-inspired magnetic nanoparticles.

[0038] First, dicarboxylated modified polyethylene glycol (240 mg), mercapto-polyethylene glycol (120 mg), N-hydroxysuccinimide (24 mg), N,N'-dicyclohexylcarbodiimide (36 mg), dopamine hydrochloride (16 mg), and sodium carbonate (120 mg) were dissolved in a chloroform / N,N-dimethylformamide mixed solvent (24 / 12 mL) and stirred at 45 °C for 2 hours. Then, oil-phase enzyme-inspired magnetic particles (10 mg) were added, and the reaction was carried out at 25 °C for 12 hours. After the reaction was completed, the particles were precipitated with n-hexane and centrifuged. The resulting solution was then purified and concentrated by dialyzing to obtain aqueous enzyme-inspired magnetic nanoparticles.

[0039] The morphology of the prepared aqueous enzyme-inspired magnetic nanoparticles was characterized by transmission electron microscopy, such as... Figure 7 As shown.

[0040] The hydrodynamic particle size was tested using dynamic light scattering, and the results are as follows: Figure 8 As shown.

[0041] Example 6 This embodiment provides the synthesis of aqueous magnetically neutralized ferrite-based nanoparticles.

[0042] First, dicarboxylated modified polyethylene glycol (360 mg), mercapto-polyethylene glycol (180 mg), N-hydroxysuccinimide (36 mg), N,N'-dicyclohexylcarbodiimide (54 mg), dopamine hydrochloride (24 mg), and sodium carbonate (180 mg) were dissolved in a chloroform / N,N-dimethylformamide mixed solvent (36 / 18 mL) and stirred at 45 °C for 2 hours. Then, oil-phase enzyme-inspired magnetic particles (15 mg) were added, and the reaction was carried out at 25 °C for 12 hours. After the reaction was completed, the particles were precipitated with n-hexane and centrifuged. The resulting solution was then purified and concentrated by dialyzing to obtain aqueous enzyme-inspired magnetic nanoparticles.

[0043] The morphology of the prepared aqueous enzyme-inspired magnetic nanoparticles was characterized by transmission electron microscopy, such as... Figure 9 As shown The hydrodynamic particle size was tested using dynamic light scattering, and the results are as follows: Figure 10 As shown.

[0044] Example 7 Weigh 50 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 75 mg of N-hydroxysuccinimide, and 10 mg of aqueous enzyme-inspired magnetic nanoparticles from Example 4, dissolve them in 20 mL of 2-(N-morpholino)ethanesulfonic acid buffer, add 20 mg of arginine-glycine-aspartic acid sequence, react at room temperature for 12 hours, and obtain the enzyme-inspired magnetic nanoprobe by dialysis purification and concentration.

[0045] The morphology of the prepared enzyme-inspired magnetic nanoprobes was characterized, such as... Figure 11 As shown.

[0046] The hydrodynamic particle size was tested using dynamic light scattering, and the results are as follows: Figure 12 As shown.

[0047] Its imaging performance was tested using a 9.0 T magnetic resonance imaging (MRI) device, and the results are as follows: Figure 13 As shown.

[0048] The relaxation time and probe concentration relationship were analyzed using a 9.0 T magnetic resonance imaging (MRI) device, and the results are as follows: Figure 14 As shown.

[0049] All the above results demonstrate that the enzyme-inspired magnetic nanoprobe provided in this embodiment has good T1 imaging performance under ultra-high field magnetic resonance.

[0050] Application examples This application example demonstrates the use of the enzyme-inspired magnetic nanoprobe in the detection of random transfer throughout the body, as described in Example 7.

[0051] To verify the ability of the enzyme-inspired magnetic nanoprobe (prepared according to the method in Example 7) to detect random metastatic lesions throughout the body in triple-negative breast cancer, we constructed a random metastatic model using female BALB / c mice (6-8 weeks old) via left ventricular injection of 4T1-Luc cells. Following tail vein injection of the enzyme-inspired magnetic nanoprobe, ultra-high field MRI imaging showed a significant difference in signal intensity between the metastatic area and the surrounding normal tissue as early as 2.5 hours (e.g., Figure 15 As shown in the figure, this further demonstrates that enzyme-inspired magnetic nanoprobes can achieve accurate detection of random metastatic lesions throughout the body.

[0052] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0053] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing an enzyme-inspired magnetic nanoprobe, characterized in that, Includes the following steps: Step S1: Dissolve the gold source compound and the gadolinium source compound in an oil-phase mixed solvent, inject a reducing agent and react under an inert atmosphere, wash the precipitate with a first non-polar solvent and centrifuge to obtain oil-phase enzyme-inspired magnetic nanoparticles. Step S2: The oil-phase enzyme-inspired magnetic nanoparticles are surface-modified with hydrophilic molecules in a suitable solvent system to obtain aqueous enzyme-inspired magnetic nanoparticles; the suitable solvent system is a mixture of a first polar solvent and a second non-polar solvent. Step S3: The aqueous enzyme-inspired magnetic nanoparticles are coupled with a highly specific ligand via a chemical amide linkage reaction to complete surface targeting modification, thereby obtaining the enzyme-inspired magnetic nanoprobe.

2. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 1, characterized in that, In step S1, the gold source compound is gold tetrachloride trihydrate, and the gadolinium source compound is gadolinium acetylacetone hydrate. The oil phase mixed solvent is a mixture of tetrahydronaphthalene and oleylamine; The first nonpolar solvent is selected from one or more of anhydrous ethanol, acetone, methanol, isopropanol and acetic acid.

3. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 1, characterized in that, In step S1, the reducing agent is selected from one or more of tetrabutylamine borane, trisec-butyllithium borohydride, dimethylamine borane, polyols and long-chain primary amines; The reaction is carried out at a temperature of 4-50°C for 30-60 minutes. The feeding ratio of each component in the gold source compound, gadolinium source compound, and oil phase mixed solvent to the reducing agent is 0~1 mmol: 0~1 mmol: 1~10 mL: 1~10 mL: 0~1 mmol.

4. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 1, characterized in that, In step S2, a ligand exchange method is used, specifically by adding the oil-phase enzyme-inspired magnetic nanoparticles to the suitable solvent system, adding hydrophilic molecules, and reacting at room temperature to obtain aqueous-phase enzyme-inspired magnetic nanoparticles.

5. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 4, characterized in that, The first polar solvent is one or more of o-dichlorobenzene, chloroform, n-hexane, cyclohexane, and toluene; The second nonpolar solvent is one or more of acetone, ethanol, N,N-dimethylformamide, and dimethyl sulfoxide; The hydrophilic molecule is one or more of polyethylene glycol, polyvinylpyrrolidone, polydopamine, cysteine, mercaptosuccinic acid, and mercaptopropionic acid.

6. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 1, characterized in that, In step S3, the chemical amide linkage reaction specifically includes: adding aqueous enzyme-inspired magnetic nanoparticles, a catalyst, and the highly specific ligand to a second polar solvent, reacting at room temperature, and then purifying to obtain the enzyme-inspired magnetic nanoprobe.

7. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 6, characterized in that, The highly specific ligand is one or more of folic acid, arginine-glycine-aspartic acid sequence, aptamer, and CREKA peptide; The highly specific ligands correspond to specific biological factors that are highly expressed in major diseases such as tumors.

8. The method for preparing enzyme-inspired magnetic nanoprobes according to claim 6, characterized in that, The second polar solvent is one or more of 2-(N-morpholine) ethanesulfonic acid buffer, phosphate buffer, deionized water, dimethyl sulfoxide, and N,N-dimethylformamide.

9. An enzyme-inspired magnetic nanoprobe prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the enzyme-inspired magnetic nanoprobe as described in claim 9 in the preparation of contrast agents for early diagnosis of major diseases in magnetic resonance imaging.

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