Preparation method and application of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging

Abstract

Preparation method and application of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging. In this method, polyethylene glycol is used as a surfactant, and a water-soluble nano metal-organic framework compound (PEG-MOF) is prepared by a simple one-step method. The water-soluble PEG-MOF nano-probe is efficiently enriched at the breast cancer site by virtue of the long-circulation effect of PEG in the blood and the enhanced permeability and retention (EPR) effect of the nano-material, and the tumor location is accurately determined by means of T1 magnetic resonance and fluorescence multimodal imaging techniques. Under the irradiation of near-infrared light, PEG-MOF synergistically performs photodynamic therapy to induce the occurrence of ferroptosis in tumor cells. The water-soluble PEG-MOF has the advantages of simple preparation method, good repeatability, safe operation, low economic cost, etc., and has strong clinical potential in the diagnosis and treatment of breast cancer, and is expected to provide new ideas for the early clinical diagnosis and precise treatment of breast cancer.

Description

Technical Field

[0001] The present invention belongs to the technical fields of advanced functional materials and biomedicine, and particularly relates to a preparation method and application of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging. Background Art

[0002] Breast cancer is one of the most common malignant tumors, seriously threatening the lives and health of women. Breast cancer is characterized by a high incidence rate, strong invasiveness, easy recurrence and metastasis, etc., seriously threatening the lives and survival quality of breast cancer patients. Early diagnosis has an impact on the treatment and prognosis of patients and is an effective strategy to prevent most breast cancer deaths. Therefore, finding new breast cancer diagnostic and therapeutic reagents with good effects, small side effects, and both diagnostic and therapeutic functions is a problem faced and to be solved in clinical work.

[0003] Magnetic resonance imaging (MRI) technology has the advantages of strong soft tissue resolution, high spatial resolution, strong tissue penetration, and no radiation, and has become an indispensable imaging technology in clinical breast cancer diagnosis. Research shows that different chemical environments and water concentrations will produce different signal intensities, thus providing contrast between fat, tissue, and bone. Contrast agents mainly composed of paramagnetic compounds can enhance the contrast of MR images by promoting the relaxation of water near the compounds. It is reported that MRI contrast agents are divided into T1 (i.e., positive) or T2 (i.e., negative). However, radiologists tend to use T1 contrast agents because T2 contrast agents appear as dark areas and are difficult to distinguish from internal bleeding, air-tissue boundaries, or other sensitivity artifacts, resulting in inaccurate diagnosis of patients. In addition, the T1 relaxation time in animal tissues is usually much longer than the T2 relaxation time, which means that the relaxation time of T1 contrast agents can be smaller than that of T2 contrast agents to obtain the same amount of image intensity change. Currently, the gadolinium-based contrast agents (GBCAs) used clinically are all T1 contrast agents, but there is still a small risk of adverse reactions, including nephrogenic systemic fibrosis and gadolinium deposition in the human brain. Therefore, there is an urgent need to develop new T1 contrast agents with low toxicity, high relaxation degree, and safe metabolism.

[0004] At present, nanotechnology has shown high efficiency in tumor treatment and can perform tracking imaging on tissues, thus enabling early diagnosis and treatment of tumors, and is expected to become an effective integrated tumor diagnosis and treatment platform. On this basis, researchers have developed many excellent anti-tumor efficiency treatment methods, such as photodynamic therapy (PDT), photothermal therapy (PTT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT), etc. Among them, as a non-invasive early tumor diagnosis and treatment technology, PDT can not only avoid the above-mentioned toxic side effects, but also be easily combined with methods such as chemotherapy, immunotherapy, and gene therapy. It has the advantages of small trauma, high safety, no drug resistance, and precise control of treatment time, and shows great clinical potential in both early diagnosis and treatment of tumors. The PDT therapy mainly involves the conversion of the ground state of the photosensitizer to the excited state under the action of an external light source, reacting with cell substrates through electron pair transfer, and generating reactive oxygen species (ROS) products such as hydroxyl radicals (·OH), singlet oxygen ( 1 O2), hydrogen peroxide (H2O2), etc., thereby causing apoptosis of tumor cells and irreversible damage to the blood vessels in the tumor microenvironment to achieve the purpose of inhibiting tumor growth. In this reaction process, the photosensitizer plays a crucial role. Among them, porphyrin molecules are commonly used photosensitizers, but they still have the disadvantages of short light response duration, low efficiency, and fast metabolism. In addition, the hydrophobicity of porphyrin photosensitizers may cause precipitation due to aggregation before entering the tumor lesion, and then be absorbed by the skin or healthy tissues, which seriously reduces the photodynamic therapy efficacy at the lesion site and also brings non-targeted phototoxicity to normal tissues.

[0005] In recent years, metal-organic framework materials (MOFs), mainly composed of two important components, nodes and linkers, have developed rapidly due to their advantages such as high porosity, large specific surface area, adjustable pore size, and good stability. Among them, porphyrin-based metal-organic framework materials are highly ordered new organic-inorganic hybrid materials self-assembled by metal ions or metal ion clusters and porphyrin ligands through coordination bonds. The unique structure and light absorption characteristics of porphyrin make it show better properties than general MOFs during application. In addition, combining porphyrin ligands with metal-organic frameworks can effectively avoid the self-aggregation and self-quenching of porphyrin photosensitive components, enhance the fluorescence intensity of porphyrin photosensitizers, and thus be better used for fluorescence imaging of targets. At the same time, the photosensitizer encapsulated in MOFs can also be delivered to tumor tissues through the enhanced permeability and retention (EPR) effect of nanomaterials by passive targeting. In addition, surface modification and modification of MOFs can further improve the water solubility and biocompatibility of porphyrin-metal organic framework compounds, achieve enhanced PDT of tumors, and thus show more excellent photodynamic therapy effects.

[0006] Different from traditional cell necrosis and apoptosis, ferroptosis is an iron-dependent form of cell death triggered by the accumulation of lipid peroxides and the excessive production of ROS, and it is a current research hotspot in cancer treatment. ROS generated within tumor cells can be consumed by endogenous antioxidants, especially glutathione (GSH) overexpressed in the tumor microenvironment, which severely impairs the therapeutic effect of photosensitizers. Therefore, triggering oxidative stress by depleting GSH or generating ROS is a new idea for developing anti-cancer drugs. Iron-based nanomaterials can not only weaken the antioxidant capacity of cells by depleting intracellular GSH, but also utilize the Fenton reaction of iron ions to decompose H2O2 to generate ·OH, inducing ferroptosis of tumor cells while enhancing ROS-mediated apoptosis of tumor cells. Summary of the Invention

[0007] The object of the present invention is to provide a preparation method and application of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging. The preparation method is stable, reliable, and has good repeatability, with the advantages of simple steps, rich yield, safe operation, and low economic cost; the prepared PEG-MOF nano probe can not only achieve enhanced T1 magnetic resonance imaging, but also effectively overcome the problem of fluorescence quenching of porphyrin molecules, constructing a dual-modal probe with simple preparation, high magnetic resonance imaging efficiency, and long fluorescence imaging time to achieve early and accurate diagnosis of breast cancer.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging, comprising the following steps:

[0009] (1) Add meso-tetra(4-carboxyphenyl)porphine, ferric chloride hexahydrate, benzoic acid, and polyethylene glycol to N,N-dimethylformamide in sequence, and fully dissolve to obtain a reaction solution;

[0010] (2) After heating the reaction solution to 70-150 °C, stir the reaction in the dark for 5-10 h;

[0011] (3) After the reaction is complete, cool the solution to room temperature, and dialyze it with a dialysis bag with a molecular weight of 5000-8000 for 2-5 days to obtain PEG-MOF nanoparticles.

[0012] Preferably, the concentration of meso-tetra(4-carboxyphenyl)porphine in step (1) is 0.5-1.5 mg / mL.

[0013] Preferably, the mass ratio between meso-tetra(4-carboxyphenyl)porphine and ferric chloride hexahydrate in step (1) is 1:1-1:10.

[0014] Preferably, the mass ratio between meso-tetrakis(4-carboxyphenyl)porphine and benzoic acid in step (1) is 1:15 to 1:100.

[0015] Preferably, the mass ratio between meso-tetrakis(4-carboxyphenyl)porphine and polyethylene glycol in step (1) is 1:10 to 1:40.

[0016] Preferably, the polyethylene glycol in step (1) is one of polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 3000, polyethylene glycol 4000, and polyethylene glycol 5000.

[0017] Preferably, the particle size of the PEG-MOF nanoparticles is 90 - 100 nm, and the surface charge is 15 - 20 mV.

[0018] Preferably, the pore size of the PEG-MOF nanoparticles is 5 - 9 nm, and the pore volume is 0.05 - 0.1 m 3 / g.

[0019] To achieve the above object, the present invention also provides the application of the PEG-MOF nanoparticles prepared by the above preparation method in the early clinical diagnosis and precise treatment of breast cancer. The PEG-MOF nanoparticles have good fluorescence and magnetic resonance imaging effects, and can induce apoptosis of tumor cells under the combined action of photodynamic therapy and ferroptosis.

[0020] The present invention uses a hydrophobic porphyrin photosensitizer (TCPP) as an organic linker, iron ions as nodes, and polyethylene glycol as a surfactant to prepare a water-soluble nano metal-organic framework compound (PEG-MOF) by a simple one-step method. This water-soluble nano metal-organic framework compound can not only perform T1 magnetic resonance imaging but also effectively perform fluorescence imaging under the irradiation of near-infrared light. Relying on the long-circulation effect of PEG in the blood and the enhanced permeability and retention (EPR) effect of nanomaterials, the water-soluble PEG-MOF nanoprobe is highly enriched at the breast cancer site, and the tumor location is accurately determined by T1 magnetic resonance and fluorescence multimodal imaging techniques. Under the irradiation of near-infrared light, TCPP in the water-soluble PEG-MOF catalyzes H2O2 in the tumor microenvironment to generate singlet oxygen ( 1 O2), achieving excellent photodynamic therapy effects. At the same time, the Fenton reaction of iron (Fe) enables PEG-MOF to consume glutathione (GSH) in the TME, inducing the occurrence of ferroptosis in tumor cells.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The nano-diagnostic agent prepared by the present invention is synthesized by a one-step method. The preparation method is stable, reliable, and has good repeatability, with the advantages of simple steps, high yield, safe operation, and low economic cost;

[0023] (2) The PEG-MOF surface-modified by the present invention using PEG has the advantages of good biocompatibility, biosafety, high catalytic activity, and modifiable biochemical activity, etc., which improves the problem of poor water solubility of traditional porphyrin-based metal-organic frameworks and is better applied to the human body;

[0024] (3) The water-soluble PEG-MOF nanoparticles prepared by the present invention, when used as an organic diagnostic agent, exhibit a significant T1 magnetic resonance enhancement effect and can overcome the deficiency of traditional gadolinium contrast agents in damaging liver and kidney functions;

[0025] (4) The water-soluble PEG-MOF nanoparticles prepared by the present invention can overcome the problem of easy fluorescence quenching of porphyrin molecules in water, perform effective near-infrared fluorescence imaging to achieve early and accurate diagnosis of breast cancer, and guide subsequent treatment.

[0026] (5) The water-soluble PEG-MOF nanoparticles prepared by the present invention can not only generate highly toxic hydroxyl radicals under the irradiation of near-infrared light but also consume glutathione under the action of iron ions, thereby inducing ferroptosis of tumor cells while performing PDT on breast cancer lesions, achieving the function of multiple killing of tumor cells. Description of the Drawings

[0027] Figure 1 It is the transmission electron microscope image of the water-soluble PEG-MOF nanoparticles of the present invention: (A) Transmission electron microscope image of the water-soluble PEG-MOF nanoparticles (scale bar 200 nm), (B) Transmission electron microscope image of the water-soluble PEG-MOF nanoparticles (scale bar 50 nm);

[0028] Figure 2 It is the elemental analysis chart of the water-soluble PEG-MOF nanoparticles prepared in the examples of the present invention;

[0029] Figure 3 It is the hydrated particle size chart of the water-soluble PEG-MOF nanoparticles prepared in the examples of the present invention;

[0030] Figure 4 It is the surface charge chart of different nanoparticles TCPP, MOF, and PEG-MOF involved in the examples of the present invention;

[0031] Figure 5 It is the ultraviolet spectrum chart of different nanoparticles TCPP, MOF, and PEG-MOF involved in the examples of the present invention;

[0032] Figure 6 The Fourier infrared spectrum of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention;

[0033] Figure 7 The diagram of the ability to generate singlet oxygen extracellularly of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention;

[0034] Figure 8 The diagram of the ability to generate hydroxyl radicals extracellularly of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention;

[0035] Figure 9 The diagram of the ability to consume glutathione extracellularly of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention: (A) Schematic diagram of the change of the ultraviolet-visible absorption spectral curve of DTNB at 485 nm with time after co-culturing PEG-MOF (37.5 mg / L) with GSH, (B) Ultraviolet-visible absorption spectra of DTNB at 485 nm after co-incubating different nanoprobes (TCPP, MOF, and PEG-MOF) with GSH;

[0036] Figure 10 The related schematic diagrams of T1 magnetic resonance imaging of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention; (A) T1 magnetic resonance imaging signal diagram, (B) T1 magnetic resonance imaging relaxation rate curve diagram;

[0037] Figure 11 The related schematic diagrams of fluorescence imaging and fluorescence signals of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention; (A) Fluorescence imaging ability diagram, (B) Diagram of the change of fluorescence signal intensity with the increase of concentration;

[0038] Figure 12 The schematic diagram of the expression of ROS at the cellular level of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention: (A) Schematic diagram of the ability to generate ROS in breast cancer 4T1 cells under light / non-light conditions in different concentrations of PEG-MOF aqueous solutions by active oxygen fluorescence probe (DCFH-DA) staining experiment; (B) Schematic diagram of the growth inhibitory effect on breast cancer 4T1 cells under light / non-light conditions in different concentrations of PEG-MOF aqueous solutions by live / dead cell double staining experiment;

[0039] Figure 13Schematic diagrams related to the evaluation of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention at the cellular level by magnetic resonance imaging: (A) T1-weighted images after incubation of aqueous solutions of PEG-MOF with breast cancer 4T1 cells at different concentrations; (B) Statistical chart of signal value measurements of T1-weighted images after incubation of aqueous solutions of PEG-MOF with breast cancer 4T1 cells at different concentrations.

[0040] Figure 14 Fluorescence imaging level evaluation diagram of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention at the cellular level;

[0041] Figure 15 Schematic diagrams for the imaging evaluation of tumor tissues in vivo of the water-soluble PEG-MOF nanoparticles prepared in the embodiments of the present invention: (A) T1WI images of small animals in the PEG-MOF model group at different time points, (B) Line graph of MRI semi-quantitative analysis, (C) In vivo fluorescence imaging of small animals in the PEG-MOF model group at different time points, (D) Semi-quantitative analysis of fluorescence intensity of in vivo fluorescence imaging of small animals. Detailed implementation manners

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of this specification, rather than all the embodiments. Based on the embodiments in this specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this specification. The following describes the preferred embodiments of the present invention. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0044] All raw materials and reagents in the embodiments of the present application are purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0045] Example 1

[0046] A preparation method of a magnetic resonance / fluorescence imaging-guided photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent is as follows:

[0047] (1) Dissolve 0.026 g of meso - tetra(4 - carboxyphenyl)porphine (TCPP), 0.061 g of ferric chloride hexahydrate (FeCl3·6H2O), 0.703 g of benzoic acid, and 0.650 g of polyethylene glycol 2000 (Mw = 2000) successively and thoroughly in 25 ml of N,N - dimethylformamide (DMF) to obtain a reaction solution;

[0048] (2) Heat the reaction solution to 95 °C and react for 7 h under stirring at 500 rpm in the dark;

[0049] (3) After the reaction is complete, cool the solution to room temperature and dialyze the reaction solution with a dialysis bag with a molecular weight of 8000 for 3 days to obtain water - soluble PEG - MOF nanoparticles.

[0050] As Figure 1 shown, the prepared PEG - MOF nanoparticles are shuttle - shaped near - spherical with a particle size of about 90 nm, having a uniform size ratio and good dispersibility. Elemental analysis verified the distribution of C, Fe, N, and O elements in the nanoparticles ( Figure 2 ), indicating the formation of a porphyrin - iron - based nano - framework with good stability. The hydrated particle size of PEG - MOF measured by a particle size analyzer is about 90 nm ( Figure 3 ), which is consistent with the TEM result. In addition, the surface charges of TCPP, nano - metal - organic framework compound (MOF), and PEG - MOF (PEG - coated MOF) were measured with this instrument, and it was found that the surface of PEG - MOF is positively charged ( Figure 4 ), while the surface charges of TCPP and MOF are both negative, further proving the successful preparation of water - soluble PEG - MOF. After ultraviolet spectroscopy tests on different probes, it was found that the characteristic absorption peak of PEG - MOF is around 425 nm, while the characteristic absorption peaks of TCPP and MOF are around 415 nm ( Figure 5 ), proving that water - soluble PEG - MOF has the basic framework structure of MOF. The Fourier transform infrared test results show that ( Figure 6 ) PEG - MOF shows the stretching vibration absorption peak of the C - H bond identical to that of MOF around 1470 - 1350 cm -1 , and shows the absorption peak of the C - O bond identical to that of PEG around 1300 - 1000 cm -1 , indicating that PEG was successfully modified on its surface without destroying the original MOFs structure, forming water - soluble PEG - MOF.

[0051] As Figure 7 shown, in the presence of H2O2 and near - infrared light (808 nm, 1 W / cm 2) Under the combined action of, the ultraviolet absorption photometric values of 9,10-anthracenediyl-bis(methylenedipropanedioic acid) (ABDA) blended with PEG-MOF decrease most rapidly at 380 nm and 400 nm, indicating that its · 1 O2 generation ability is higher than that of TCPP and MOF. Under the irradiation of 808 nm near-infrared light (1 W / cm 2 ), the absorption peak of the PEG-MOF aqueous solution (pH = 5.5) added with H2O2 at 650 nm continuously decreases with the prolongation of time ( Figure 8 ), indicating that PEG-MOF can effectively generate ·OH. In addition, in this invention, 5,5α-dithiobis(2-nitrobenzoic acid) (DTNB), an indicator for glutathione index detection, is used as an indicator to verify the consumption efficiency of PEG-MOF nanomaterials for GSH. As Figure 9 shown, when using PEG-MOG nanoparticles to incubate with GSH, the absorbance value of DTNB decreases faster than that when using TCPP and hydrophobic MOF alone, indicating that it has a higher glutathione consumption rate. These results indicate that PEG-MOF can not only generate a large amount of ROS under the irradiation of near-infrared light, but also consume GSH through the Fenton reaction of Fe 2+ to induce the occurrence of ferroptosis in tumor cells.

[0052] To verify the magnetic resonance and fluorescence imaging capabilities of PEG-MOF, this invention prepared a series of PEG-MOF solutions with concentration gradients and performed magnetic resonance and fluorescence imaging on them. As Figure 10 known from A, as the Fe concentration increases, the T1 WI signal of the PEG-MOF nanoparticle aqueous solution is higher, indicating that PEG-MOF has obvious T1 imaging ability. Through calculation, the T1 relaxation rate of PEG-MOF nanoparticles is 6.876 mM -1 s -1 ( Figure 10 B), slightly higher than the relaxation rate of clinically used Gd-based contrast agents. As known from Figure 11 A, the fluorescence signal intensity of the PEG-MOF nanoprobe gradually increases with the increase of the TCPP concentration, and its corresponding fluorescence intensity also gradually increases ( Figure 11 B). These experimental results indicate that the PEG-MOF nanoprobe has excellent magnetic resonance and fluorescence imaging capabilities.

[0053] The in vitro test results show that the water-soluble PEG-MOF nanoprobe can generate ROS under the irradiation of near-infrared light to achieve the purpose of regulating the tumor microenvironment. Therefore, this invention evaluates the level of ROS generated by this probe at the cellular level through a reactive oxygen fluorescence probe, and the results are as Figure 12As shown in A. Compared with the non-irradiated group, 4T1 cells under near-infrared light irradiation showed obvious green fluorescence, and the fluorescence intensity increased with the increase in the concentration of PEG-MOF, indicating that 4T1 cells co-incubated with PEG-MOF could only generate ROS under near-infrared light irradiation, and the concentration of generated ROS increased with the increase in the concentration of PEG-MOF. The results of the cell viability and cytotoxicity assay showed ( Figure 12 B) that under near-infrared light irradiation, with the increase in the concentration of PEG-MOF, the red color representing dead cells increased. This was consistent with the results of the ROS experiment, further indicating the function of PEG-MOF in generating ROS in tumor cells and inhibiting tumor cell growth.

[0054] To verify the magnetic resonance and fluorescence intracellular imaging capabilities of PEG-MOF, the present invention prepared PEG-MOF solutions with different concentration gradients and performed intracellular magnetic resonance and fluorescence imaging on them. A 3T magnetic resonance imaging instrument was used to explore the T1 imaging ability of PEG-MOF nanoparticles in 4T1 breast cancer cells. As Figure 13 shown in A, with the increase in the Fe concentration, 4T1 breast cancer cells phagocytosing PEG-MOF nanoparticles became brighter, and the statistically measured T1 WI signal was also higher ( Figure 13 B), indicating that its T1 imaging ability in 4T1 breast cancer cells was getting stronger. As Figure 14 shown, the fluorescence signal intensity of PEG-MOF in 4T1 breast cancer cells increased with the increase in the TCPP concentration. The above experimental results showed that the PEG-MOF nanoprobe still had excellent T1 magnetic resonance and fluorescence imaging capabilities at the cellular level.

[0055] Next, the present invention used BALB / c mice with breast cancer to explore the tumor penetration of the PEG-MOF nanoprobe and its T1 magnetic resonance / fluorescence dual-modal imaging effect in vivo. As Figure 15 shown in A, the tumor gradually became brighter after intravenous injection of the PEG-MOF nanoprobe through the tail vein and was the brightest at 2 h. By measuring the T1 signal intensity values of the tumor and the surrounding muscle, it could be known ( Figure 15 B) that the T1 signal intensity in the tumor gradually increased with the passage of time and reached the enhancement peak at 2 h (T1 signal value about 11278 ± 278), and the signal ratio of the tumor tissue to the surrounding soft tissue was 1.6:1. As time passed, the enhancement degree of the tumor mass gradually weakened, and the enhancement characteristics of the tumor mass were more obvious on the pseudocolor image. About 24 h later, the tumor mass signal gradually returned to the state during plain scan. The signal intensity of the surrounding soft tissue of the tumor basically did not change, indicating that PEG-MOF could accumulate in the tumor through the enhanced permeability and retention (EPR) effect and perform effective T1 magnetic resonance imaging. After performing in vivo fluorescence imaging on the tumor-bearing mice injected with PEG-MOF intravenously, it was found that the fluorescence signal of the tumor gradually increased with the passage of time and was the brightest at 2 hFigure 15 C). It can be known by measuring the fluorescence signal in the tumor that ( Figure 15 D), the intensity of the fluorescence signal in the tumor gradually increases with the extension of time and reaches the highest value at 2 h. As time goes by, the fluorescence signal of the tumor gradually weakens and returns to the intensity before drug injection after 24 h.

[0056] Example 2

[0057] A preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging is as follows:

[0058] (1) 0.026 g of meso-tetra(4-carboxyphenyl)porphine (TCPP), 0.130 g of ferric chloride hexahydrate (FeCl3·6H2O), 0.780 g of benzoic acid and 0.780 g of polyethylene glycol (PEG, Mw = 2000) are successively and fully dissolved in 25 ml of N,N-dimethylformamide (DMF) to obtain a reaction solution;

[0059] (2) The reaction solution is heated to 95 °C and reacted for 7 h under stirring in the dark at 500 rpm;

[0060] (3) After the reaction is complete, the solution is cooled to room temperature, and the reaction solution is dialyzed with a dialysis bag with a molecular weight of 8000 for 3 days to obtain water-soluble PEG-MOF nanoparticles.

[0061] Example 3

[0062] A preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging is as follows:

[0063] (1) 0.026 g of meso-tetra(4-carboxyphenyl)porphine (TCPP), 0.061 g of ferric chloride hexahydrate (FeCl3·6H2O), 0.703 g of benzoic acid and 0.650 g of polyethylene glycol (PEG, Mw = 3000) are successively and fully dissolved in 25 mL of N,N-dimethylformamide (DMF) to obtain a reaction solution;

[0064] (2) The reaction solution is heated to 95 °C and reacted for 7 h under stirring in the dark at 500 rpm;

[0065] (3) After the reaction is complete, the solution is cooled to room temperature, and the reaction solution is dialyzed with a dialysis bag with a molecular weight of 8000 for 3 days to obtain water-soluble PEG-MOF nanoparticles.

[0066] The PEG-MOF nanoprobes prepared in the above embodiments can not only achieve enhanced T1 magnetic resonance imaging, but also effectively overcome the problem of fluorescence quenching of porphyrin molecules, constructing a dual-modal probe with simple preparation, high magnetic resonance imaging efficiency, and long fluorescence imaging time to achieve early and accurate diagnosis of breast cancer.

[0067] For those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments. The embodiments are exemplary and non-limiting. The protection scope of the present invention is defined by the appended claims rather than the above description. Therefore, any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging, characterized in that, The method includes the following steps: (1) Add meso-tetra(4-carboxyphenyl)porphine, ferric chloride hexahydrate, benzoic acid, and polyethylene glycol into N,N-dimethylformamide in sequence, and fully dissolve them to obtain a reaction solution; the concentration of meso-tetra(4-carboxyphenyl)porphine is 0.5 - 1.5 mg / mL; the mass ratio between meso-tetra(4-carboxyphenyl)porphine and ferric chloride hexahydrate is 1:1 - 1:10; the mass ratio between meso-tetra(4-carboxyphenyl)porphine and benzoic acid is 1:15 - 1:100; the mass ratio between meso-tetra(4-carboxyphenyl)porphine and polyethylene glycol is 1:10 - 1:40; (2) Heat the reaction solution to 70 - 150 °C, and then stir the reaction in the dark for 5 - 10 h; (3) After the reaction is complete, cool the solution to room temperature, and dialyze it with a dialysis bag with a molecular weight of 5000 - 8000 for 2 - 5 days to obtain PEG-MOF nanoparticles.

2. The preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging according to claim 1, characterized in that, In step (1), the polyethylene glycol is one of polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 3000, polyethylene glycol 4000, and polyethylene glycol 5000.

3. The preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging according to claim 1, characterized in that, The particle size of the PEG-MOF nanoparticles is 90 - 100 nm, and the surface charge is 15 - 20 mV.

4. The preparation method of a photodynamic / ferroptosis nano metal-organic diagnostic and therapeutic agent guided by magnetic resonance / fluorescence imaging according to claim 1, characterized in that, The pore size of the PEG-MOF nanoparticles is 5 - 9 nm, and the pore volume is 0.05 - 0.1 m³ / g.

5. Use of the PEG-MOF nanoparticles prepared by the preparation method according to any one of claims 1 - 4 in the preparation of drugs for early clinical diagnosis and precise treatment of breast cancer. The PEG-MOF nanoparticles have fluorescence and magnetic resonance imaging effects, and can induce apoptosis of tumor cells under the combined action of photodynamic therapy and ferroptosis.

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