Antitumor bimetallic nano-organic material

Abstract

This invention discloses an antitumor bimetallic nanomaterial, comprising a drug component, a bimetallic framework core, and a functional shell layer arranged sequentially from the inside out. The bimetallic framework core is a bimetallic doped zeolite imidazole ester framework material, with two different transition metal ions serving as coordination nodes, self-assembling with imidazole organic ligands through coordination bonds to form a three-dimensional porous framework structure. The functional shell layer is a manganese dioxide shell layer in situ coated on the outer surface of the bimetallic framework core. The drug component is an antitumor traditional Chinese medicine active monomer loaded in the internal pores of the bimetallic framework core; specifically, it is a zinc-cobalt bimetallic zeolite imidazole ester framework loaded with curcumin and coated with a manganese dioxide core-shell nanocomposite material (Cur@ZnCo-ZIF@MnO2).

Description

Technical Field

[0001] This invention relates to the field of antitumor materials technology, specifically to an antitumor bimetallic nano-organic material. Background Technology

[0002] Malignant tumors, as a complex disease characterized by disordered cell proliferation regulation mechanisms and strong invasiveness and metastasis, are a challenge that clinical medicine needs to overcome, affecting the health and quality of life of people worldwide. Currently, mainstream clinical interventions for solid tumors include surgical resection, systemic chemotherapy, local radiotherapy, and immunotherapy. Each of these single-treatment regimens has inherent limitations: surgery can only remove the visible solid tumor mass, failing to eliminate microscopic tumor infiltrates, circulating tumor cells, and dormant tumor stem cells that infiltrate surrounding normal tissues. Postoperative residual lesions easily induce local tumor recurrence and distant organ metastasis. Chemotherapy alone relies on cytotoxic drugs to indiscriminately kill rapidly dividing cells, and long-term use easily induces multidrug resistance in tumors. Simultaneously, systemic drug distribution leads to severe bone marrow suppression, gastrointestinal damage, and liver and kidney dysfunction, among other systemic toxic side effects. Radiotherapy alone is constrained by the hypoxic microenvironment of tumor tissue; tumor cells in hypoxic areas have significantly increased radiation tolerance and decreased radiosensitivity, making it difficult to eradicate all tumor cells and resulting in a persistently high risk of recurrence. Immunotherapy alone faces practical problems such as antagonism of the tumor immunosuppressive microenvironment, insufficient immune cell infiltration, and low overall response rates. The efficacy of various single therapies has a clear ceiling; relying on a single pathway is insufficient to achieve radical tumor cure, becoming a major bottleneck restricting the improvement of clinical prognosis in cancer.

[0003] Natural Chinese herbal active monomers possess unique advantages such as multi-target regulation of tumor proliferation, inhibition of angiogenesis, reversal of tumor drug resistance, regulation of the body's immunity, and mild toxicity. Compared with traditional chemical antitumor drugs, they have higher development safety and application potential, and have received widespread research attention in the field of antitumor targeted formulation development in recent years. However, most free Chinese herbal active monomers have significant shortcomings in their physicochemical properties, generally exhibiting extremely poor water solubility, imbalanced lipid-water partition coefficients, short in vivo half-life, and easy rapid metabolism and clearance by the liver and kidneys after intravenous injection. This makes it difficult for the drugs to effectively accumulate at the tumor lesion site after systemic administration. At the same time, free monomers lack the ability to target and enrich tumors, and tend to be distributed non-specifically in normal tissues. This not only significantly reduces the effective drug concentration at the lesion site, making it difficult to exert the ideal antitumor efficacy, but also causes hidden toxic side effects to normal tissues, resulting in generally low overall bioavailability in vivo. Even with existing simple carrier encapsulation modification schemes, they can only slightly improve drug solubility and cannot simultaneously meet multiple requirements such as active targeted enrichment, microenvironment-controlled drug release, and reduced system clearance rate. They cannot fundamentally solve the practical dilemma of insufficient drug-likeness of traditional Chinese medicine monomers and limited clinical translation.

[0004] Bimetallic nano-organic framework-derived nano-organic composite materials rely on the synergistic coordination of two metal ions to construct a multi-level porous structure. They possess excellent physicochemical properties such as large specific surface area, tunable pore structure, high loading capacity, easy surface functionalization modification, controllable metal sites, and responsive degradation. They show promising application prospects in areas such as drug loading and delivery, tumor microenvironment-responsive drug release, and the construction of multi-mode imaging probes.

[0005] Most of the publicly reported research on bimetallic nano-organic antitumor materials has a relatively simple design concept, often focusing only on enhancing the efficacy of a single drug loading or constructing a single imaging function. It is difficult to systematically solve the technical problems such as the easy relapse of single therapy and the low bioavailability of traditional Chinese medicine monomers. The synergistic mechanism design of the two metal components in some material systems is weak, and the synergistic effect of bimetallic sites in catalytic therapy, chemokinetic therapy, reactive oxygen generation, and multimodal imaging tracking has not been fully utilized. The overall antitumor efficacy, targeting specificity, and integrated diagnosis and treatment of the materials still have room for optimization. Summary of the Invention

[0006] To address the aforementioned problems in existing technologies, this invention provides an antitumor bimetallic nanomaterial.

[0007] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: An antitumor bimetallic organic nanomaterial comprises, from the inside out, a drug component, a bimetallic framework core, and a functional outer shell layer; The bimetallic framework core is a bimetallic doped zeolite imidazole ester framework material, which uses two different transition metal ions as coordination nodes and self-assembles with imidazole organic ligands through coordination bonds to form a three-dimensional porous framework structure. The functional outer shell is a manganese dioxide shell layer that is in situ coated on the outer surface of the bimetallic skeleton core; The drug component is an anti-tumor traditional Chinese medicine active monomer loaded in the internal pores of the bimetallic framework core; Specifically, it is a zinc-cobalt bimetallic zeolite imidazole ester framework loaded with curcumin and coated with manganese dioxide core-shell nanocomposite material (Cur@ZnCo-ZIF@MnO2).

[0008] A method for preparing an antitumor bimetallic organic nanomaterial includes the following steps: (1) Synthesis of bimetallic zeolite imidazole ester framework (ZIF) nanoparticles: The first metal salt, the second metal salt and 2-methylimidazolium are mixed in a solvent and a coordination reaction is carried out to generate bimetallic ZIF nanoparticles containing the first metal ion and the second metal ion. (2) Loading Chinese medicine monomers: The bimetallic ZIF nanoparticles are dispersed in a solution containing Chinese medicine monomers, and the Chinese medicine monomers are loaded into the pores of the bimetallic ZIF nanoparticles by stirring to obtain drug-loaded bimetallic ZIF nanoparticles. (3) Coating with a manganese dioxide shell: The drug-loaded bimetallic ZIF nanoparticles are dispersed in an alkaline buffer solution. Dopamine monomer and potassium permanganate solution are added sequentially under stirring. The potassium permanganate is reduced by the in-situ polymerization reaction of dopamine, thereby forming a manganese dioxide shell on the surface of the drug-loaded bimetallic ZIF nanoparticles. After solid-liquid separation, washing and drying, the antitumor bimetallic nano-organic material is obtained.

[0009] Preferably, in step (1), the first metal salt is a zinc salt and the second metal salt is a cobalt salt; the molar ratio of the first metal salt to the second metal salt is (1:10)-(10:1); and the particle size of the bimetallic ZIF nanoparticles is 30-200 nm.

[0010] Preferably, in step (1), the zinc salt is zinc nitrate, zinc acetate or its hydrate; the cobalt salt is cobalt nitrate, cobalt acetate or its hydrate; the solvent is methanol or water; the temperature of the coordination reaction is 20-30 ℃, and the reaction time is 1-6 hours.

[0011] Preferably, in step (2), the herbal monomer is selected from at least one of curcumin, berberine, tripterygium oleracea, gambogeylic acid, and ginsenoside Rg3; the concentration of the herbal monomer in the solution is 0.2-5 mg / mL; the mass ratio of the bimetallic ZIF nanoparticles to the herbal monomer is 1:(0.1-1.5), and the stirring loading time is 8-24 hours.

[0012] Preferably, in step (3), the alkaline buffer solution is a tris(hydroxymethyl)aminomethane hydrochloride buffer solution with a pH of 8.0 to 9.0; the dopamine is dopamine hydrochloride; the mass ratio of the drug-loaded bimetallic ZIF nanoparticles to dopamine hydrochloride is 1:(0.5-2); the mass ratio of potassium permanganate to dopamine hydrochloride is (0.5-2):1; the reaction time for forming the manganese dioxide shell is 1-6 hours, and the reaction temperature is 15-35 ℃.

[0013] Preferably, the material has a core-shell structure, with its core being a bimetallic zeolite imidazole ester framework nanoparticle loaded with traditional Chinese medicine monomers, and its shell being a manganese dioxide layer wrapped around the outer surface of the core. The coordination structure of the bimetallic zeolite imidazole ester framework nanoparticles simultaneously contains a first metal ion and a second metal ion, which together constitute the bimetallic active component of the organic material.

[0014] Preferably, the first metal ion is Zn. 2+ The second metal ion is Co. 2+ Zn 2+ With Co 2+ The molar ratio is (1:5) - (5:1); The herbal monomers are selected from at least one of curcumin, berberine, tripterygium oleracea, gambogeylic acid, and ginsenoside Rg3; The material has an average hydrated particle size of 80-250 nm, wherein the thickness of the manganese dioxide shell is 5-40 nm.

[0015] Preferably, the material degrades under acidic and high hydrogen peroxide conditions simulating the tumor microenvironment, releasing Co. 2+ Mn 2+ Ions and the aforementioned traditional Chinese medicine monomers; The released Mn 2+ Ions, used as contrast agents in T1-weighted magnetic resonance imaging, generate real-time imaging signals that reflect the drug delivery and release process. Simultaneously, the changes in the intensity of these imaging signals are positively correlated with material degradation and the degree of drug release, forming a feedback mechanism for real-time monitoring of the treatment process. The released Mn 2+ Ions and Co 2+ Ions synergistically catalyze the generation of cytotoxic hydroxyl radicals from hydrogen peroxide within tumor cells, achieving enhanced chemokinetic therapy. Combined with the chemotherapeutic effects of the aforementioned traditional Chinese medicine monomers, this produces a synergistic antitumor effect.

[0016] Preferably, in a buffer solution at pH 5.0-6.5 containing 100 μM-10 mM hydrogen peroxide, the Mn content of the material was measured over 24 hours. 2+ Cumulative release rate greater than 50%, Co 2+ The cumulative release rate is greater than 30%, and the cumulative release rate of the herbal monomers is greater than 60%.

[0017] Application of antitumor bimetallic nano-organic materials in the preparation of magnetic resonance imaging-mediated tumor combination therapy agents, wherein the combination therapy includes T1-weighted magnetic resonance imaging, enhanced chemokinetic therapy, and chemotherapy.

[0018] The beneficial effects of this invention are: A bimetallic nanomaterial for antitumor activity, the manganese dioxide shell constructed in this invention can specifically and rapidly degrade and release a large amount of Mn in response to the weak acidity and high concentration of hydrogen peroxide in the tumor microenvironment. 2+ Ions. Mn 2+As a highly efficient T1-weighted magnetic resonance imaging (MRI) contrast agent, it can instantly illuminate tumor areas, and the magnitude of its signal enhancement is positively correlated with the degree of material degradation and the release of traditional Chinese medicine monomers. It provides medical staff with a non-invasive, real-time imaging feedback mechanism, enabling them to accurately monitor the drug delivery process and predict efficacy through changes in MRI signals. This achieves a visible combination of diagnosis and treatment, overcoming the drawbacks of traditional chemotherapy regimens where drug distribution and efficacy cannot be assessed in real time.

[0019] This treatment regimen integrates three treatment modalities to create a cascaded, amplified synergistic therapeutic effect. Chemotherapy involves the precise delivery of loaded traditional Chinese medicine monomers to the tumor site, with sustained release directly killing tumor cells. Enhanced chemokinetics includes the use of a bimetallic ZIF core to degrade and release Co... 2+ Mn ions released from the degradation of the manganese dioxide shell 2+ Ions, forming a dual-effect Fenton / Fenton-like catalytic center, efficiently and synergistically catalyze the high expression of hydrogen peroxide in tumor cells, generating highly toxic hydroxyl radicals far exceeding those of single-metal systems, thus achieving oxidative killing of tumor cells. Furthermore, the oxygen generated during the degradation of manganese dioxide effectively improves the hypoxic microenvironment of tumor tissues, weakens the radiotherapy and chemotherapy resistance of tumor cells, and provides raw materials for oxygen-dependent chemical kinetic processes, enhancing the efficacy of combined therapy. This triple synergistic mechanism results in overall antitumor activity far exceeding the sum of any single therapy.

[0020] Unlike traditional monometallic ZIFs, the bimetallic ZIF directly synthesized in this invention offers advantages including optimized drug loading and controlled release: by adjusting the ratio of the two metal ions, the pore size, polarity, and structural rigidity of the organic framework can be controlled at the atomic scale, thereby improving the loading capacity and encapsulation stability of traditional Chinese medicine monomers and achieving more sensitive pH-responsive release, reducing premature drug leakage at non-target sites. It also includes endogenous synergistic catalysis: cobalt ions in the framework and subsequently released manganese ions directly constitute a bimetallic catalytic platform, whose atomic-level dispersion characteristics provide maximum exposure of catalytically active sites, resulting in significantly higher catalytic efficiency than physically mixed systems.

[0021] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation

[0022] The technical solutions in the embodiments of this disclosure will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0023] Example 1: Preparation of curcumin@Zn / Co-ZIF (molar ratio 1:1)@MnO2 nanomaterials Step (1): Synthesis of bimetallic Zn / Co-ZIF nanoparticles Weigh 0.148 g (0.5 mmol) of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.145 g (0.5 mmol) of cobalt nitrate hexahydrate (Co(NO3)2·6H2O), and dissolve them together in 20 mL of anhydrous methanol. The dissolution is assisted by sonication for 5 minutes to obtain a clear metal salt precursor solution (solution A). Separately weigh 1.64 g (20 mmol) of 2-methylimidazole (2-MIM), dissolve it in 20 mL of anhydrous methanol, and stir until completely dissolved to obtain a ligand solution (solution B).

[0024] Under constant temperature of 25 °C and magnetic stirring at 500 rpm, solution A was rapidly poured into solution B. Upon mixing, the solution gradually changed from light pink to a turbid purple. After stirring for another 3 hours, the product was collected by centrifugation at 12000 rpm for 10 minutes, and the supernatant was discarded. The precipitate was washed three times with anhydrous methanol (20 mL each time), and centrifuged after each wash. The final product was placed in a vacuum drying oven and dried at 60 °C for 12 hours to obtain a light purple powdery solid, which was the bimetallic zeolite imidazole ester framework nanoparticle (denoted as Zn / Co-ZIF-1:1). Inductively coupled plasma optical emission spectrometry (ICP-OES) determined that the actual molar ratio of Zn to Co in the product was approximately 0.96:1.02, the average particle size was approximately 85 nm, and the specific surface area was approximately 1480 m². 2 / g.

[0025] Step (2): Loading the herbal monomer curcumin 20 mg of the Zn / Co-ZIF-1:1 nanoparticles prepared above were ultrasonically dispersed in 10 mL of anhydrous ethanol solution of curcumin (Cur) (curcumin concentration: 2.0 mg / mL), and ultrasonicated for 10 minutes to ensure thorough dispersion. The resulting suspension was placed in a constant-temperature shaker and adsorbed at 150 rpm for 24 hours at 25 °C in the dark. After adsorption, the drug-loaded particles were collected by centrifugation at 12000 rpm for 15 minutes. The precipitate was rapidly washed twice with a small amount of anhydrous ethanol (approximately 2 mL) to remove loosely adsorbed drug from the surface. The product was vacuum dried at 40 °C for 8 hours to obtain an orange-yellow powder, denoted as Cur@Zn / Co-ZIF-1:1.

[0026] The content of residual curcumin in the supernatant and washing solution was determined by ultraviolet-visible spectrophotometry. The curcumin loading was calculated to be 12.8 wt%, which means that each milligram of carrier was loaded with 0.128 milligrams of curcumin, and the encapsulation efficiency was 76.8%.

[0027] Step (3): Encapsulation of manganese dioxide shell Weigh 10 mg of the above Cur@Zn / Co-ZIF-1:1 powder and ultrasonically disperse it in 20 mL of Tris-HCl buffer (pH 8.5, 10 mM) to form a homogeneous suspension. Add 5.0 mg of dopamine hydrochloride while stirring at room temperature, and continue stirring for 30 minutes to allow the dopamine monomer to be fully adsorbed and prepolymerized on the surface of the nanoparticles.

[0028] Subsequently, 10 mL of potassium permanganate (KMnO4) aqueous solution (concentration 1.0 mg / mL, containing a total of 10 mg KMnO4) was slowly added dropwise at a rate of 0.5 mL / min using a syringe pump. During the addition, the color of the reaction solution gradually changed from light orange to dark brown, and finally to black. After the addition was complete, the reaction was continued to be stirred at room temperature in the dark for 4 hours.

[0029] After the reaction was complete, the product was collected by centrifugation at 15,000 rpm for 15 minutes. The precipitate was washed repeatedly with deionized water, 20 mL each time, for a total of 5 times, until the supernatant was completely colorless and transparent, removing unreacted dopamine and byproduct ions. Finally, the product was freeze-dried for 48 hours to obtain a black, fluffy powder, which was the final target product—a bimetallic nanomaterial, denoted as Cur@Zn / Co-ZIF-1:1@MnO2.

[0030] Transmission electron microscopy (TEM) revealed that the material exhibits a uniform core-shell spherical structure with a core diameter of approximately 85 nm and a continuous, dense outer MnO2 shell with a thickness of approximately 12 ± 3 nm. Dynamic light scattering (DLS) measured an average hydrated particle size of approximately 138 nm and a Zeta potential of approximately -22.5 mV. X-ray photoelectron spectroscopy (XPS) confirmed the characteristic peaks of Zn 2p, Co 2p, and Mn 2p, demonstrating the successful recombination of the bimetallic core and the MnO2 shell.

[0031] Example 2: Preparation of triptolide@Zn / Co-ZIF (molar ratio 3:1)@MnO2 nanomaterials Step (1): Synthesis of bimetallic Zn / Co-ZIF (3:1) The amount of Zn(NO3)2·6H2O was adjusted to 0.223 g (0.75 mmol), the amount of Co(NO3)2·6H2O was adjusted to 0.073 g (0.25 mmol), and the amount of 2-methylimidazole remained at 1.64 g (20 mmol). 20 mL of methanol was used as the solvent for each ingredient. The reaction was stirred at 25 °C for 2 hours. The remaining operations were the same as in step (1) of Example 1. The actual molar ratio of the obtained product Zn / Co-ZIF-3:1 was confirmed by ICP-OES to be approximately 2.9:1.0, and the particle size was approximately 95 nm.

[0032] Step (2): Loading triptolide 20 mg of Zn / Co-ZIF-3:1 powder was weighed and ultrasonically dispersed in 10 mL of a dimethyl sulfoxide / water mixed solvent (volume ratio 1:1, triptolide concentration 1.5 mg / mL) containing triptolide (Cel). Adsorption was performed by shaking at 25 °C in the dark for 18 hours. The product was collected by centrifugation, washed twice with a small amount of the mixed solvent, and dried under vacuum at 40 °C. The resulting product was designated Cel@Zn / Co-ZIF-3:1. High-performance liquid chromatography (HPLC) analysis showed that the triptolide loading was 9.6 wt%, and the encapsulation efficiency was 64.8%.

[0033] Step (3): Coat with a thicker MnO2 shell 10 mg of Cel@Zn / Co-ZIF-3:1 was dispersed in 20 mL of Tris-HCl buffer (pH 8.2, 10 mM), and 8.0 mg of dopamine hydrochloride was added. The mixture was stirred and adsorbed for 40 minutes. Then, 15 mL of KMnO4 solution (concentration 1.2 mg / mL, containing a total of 18 mg of KMnO4) was slowly added dropwise, and the reaction was stirred at room temperature for 3.5 hours. The post-treatment was the same as step (3) in Example 1. The resulting product was named Cel@Zn / Co-ZIF-3:1@MnO2. TEM showed that the MnO2 shell thickness was approximately 20 ± 4 nm, and the average hydrated particle size of DLS was approximately 158 nm.

[0034] Example 3: Preparation of berberine@Zn / Co-ZIF (molar ratio 1:3)@MnO2 nanomaterials Step (1): Synthesis of bimetallic Zn / Co-ZIF (1:3) Deionized water was used instead of methanol as the solvent. 0.074 g (0.25 mmol) of Zn(NO3)2·6H2O and 0.218 g (0.75 mmol) of Co(NO3)2·6H2O were dissolved in 20 mL of deionized water, and 1.64 g of 2-methylimidazole was dissolved in 20 mL of deionized water. The reaction was stirred at 30 °C for 1.5 hours. The rest of the reaction was the same as step (1) in Example 1. The actual molar ratio of the obtained product Zn / Co-ZIF-1:3 was approximately 1:3.1, and the particle size was approximately 65 nm.

[0035] Step (2): Loading berberine 20 mg of Zn / Co-ZIF-1:3 powder was weighed and ultrasonically dispersed in 10 mL of berberine hydrochloride (Ber) aqueous solution (concentration 3.0 mg / mL). The pH was pre-adjusted to 8.0 to improve drug solubility and affinity for the matrix. Adsorption was performed at 30 °C with shaking in the dark for 12 hours. After centrifugation and washing, the product was vacuum dried at 40 °C. The product was designated Ber@Zn / Co-ZIF-1:3. The berberine loading was 15.2 wt%, and the encapsulation efficiency was 82.5%.

[0036] Step (3): Coating with a thin MnO2 shell Ber@10 mg Zn / Co-ZIF-1:3 was dispersed in 20 mL Tris-HCl buffer (pH 9.0), and 3.0 mg dopamine hydrochloride was added. The mixture was stirred for 20 minutes. 8 mL of KMnO4 solution (concentration 0.75 mg / mL, containing a total of 6 mg KMnO4) was slowly added dropwise, and the reaction was carried out at room temperature with stirring for 5 hours. Post-treatment was the same as before. The product was designated Ber@Zn / Co-ZIF-1:3@MnO2. The MnO2 shell thickness was approximately 6 ± 2 nm, and the average hydrated particle size of DLS was approximately 98 nm.

[0037] Example 4: Preparation of gambogeylic acid@Zn / Cu-ZIF@MnO2 nanomaterials This embodiment demonstrates an implementation in which cobalt in a bimetallic ZIF is replaced by another transition metal, copper (Cu), and loaded with gambogic acid (GA).

[0038] Step (1): Synthesis of bimetallic Zn / Cu-ZIF Zinc nitrate and copper nitrate were used as metal sources. 0.148 g (0.5 mmol) of Zn(NO3)2·6H2O and 0.121 g (0.5 mmol) of Cu(NO3)2·3H2O were weighed and dissolved in 20 mL of methanol; 1.64 g of 2-methylimidazole was dissolved in 20 mL of methanol. The reaction was carried out at 25 °C for 4 hours. A light blue product, Zn / Cu-ZIF (molar ratio approximately 1:1), with a particle size of approximately 90 nm, was obtained.

[0039] Step (2): Loading gamboge acid 20 mg Zn / Cu-ZIF was dispersed in 10 mL of acetone / water solution of gambogeylic acid (volume ratio 3:7, gambogeylic acid concentration 1.0 mg / mL), and adsorbed at 25 °C in the dark for 20 hours. The gambogeylic acid loading in the product GA@Zn / Cu-ZIF was 8.9 wt%.

[0040] Step (3): Coating with MnO2 shell Take 10 mg of GA@Zn / Cu-ZIF, disperse it in 20 mL of Tris-HCl (pH 8.5), add 6 mg of dopamine hydrochloride, stir, and then add 12 mg of KMnO4 solution dropwise. React for 4 hours to obtain GA@Zn / Cu-ZIF@MnO2, with a MnO2 shell thickness of approximately 14 nm and a hydrated particle size of approximately 145 nm.

[0041] Example 5: Preparation and surface modification of ginsenoside Rg3@Zn / Co-ZIF(1:1)@MnO2-PEG nanomaterials This embodiment demonstrates surface polyethylene glycol (PEG) modification to improve in vivo circulation stability.

[0042] Steps (1)-(2): Same as in Example 1, but the loading drug is replaced with ginsenoside Rg3. 20 mg Zn / Co-ZIF-1:1 was dispersed in 10 mL of ginsenoside Rg3 in an ethanol / water solution (volume ratio 1:1, concentration 2.0 mg / mL), and adsorption was allowed for 24 hours. Rg3@Zn / Co-ZIF-1:1 was obtained with a loading of 11.3 wt%.

[0043] Step (3): Same as step (3) in Example 1, to obtain Rg3@Zn / Co-ZIF-1:1@MnO2.

[0044] Step (4): PEG surface modification 10 mg of the above product was weighed and ultrasonically dispersed in 10 mL of phosphate buffer (PBS, pH 7.4, 10 mM). Under nitrogen protection, 20 mg of amino-polyethylene glycol-thiol (NH2-PEG-SH, molecular weight 2000 Da) was added, and the mixture was stirred at room temperature in the dark for 2 hours. The reaction product was centrifuged at 15000 rpm for 15 minutes and washed three times with deionized water to remove unbound PEG. The product was freeze-dried to obtain the PEG-modified final product, denoted as Rg3@Zn / Co-ZIF-1:1@MnO2-PEG. After PEG modification, DLS analysis showed a slight increase in hydrated particle size to approximately 152 nm, and the Zeta potential changed from -23 mV to approximately -8 mV (near neutral), indicating that PEG grafting successfully masked the surface charge.

[0045] Example 6: Preparation of dual-drug (curcumin + berberine)@Zn / Co-ZIF (1:1)@MnO2 nanomaterials This embodiment demonstrates an implementation method for co-loading two traditional Chinese medicine monomers.

[0046] Step (1): Same as in Example 1, synthesize Zn / Co-ZIF-1:1.

[0047] Step (2): Co-loading of two drugs An ethanol / water mixture (volume ratio 7:3) containing curcumin (1.0 mg / mL) and berberine hydrochloride (1.5 mg / mL) was prepared. 20 mg of Zn / Co-ZIF-1:1 was dispersed in 10 mL of the above mixture and adsorbed at 30 °C with shaking in the dark for 16 hours. After centrifugation, washing, and drying, Cur / Ber@Zn / Co-ZIF-1:1 was obtained. The curcumin loading was 8.5 wt%, the berberine loading was 10.2 wt%, and the total drug loading was 18.7 wt%.

[0048] Step (3): Same as step (3) in Example 1, to obtain Cur / Ber@Zn / Co-ZIF-1:1@MnO2, with a MnO2 shell thickness of about 13 nm.

[0049] Example 7: Preparation of curcumin@Zn / Mn-ZIF@MnO2 nanomaterials This embodiment demonstrates an implementation where the second metal manganese (Mn) in the bimetallic ZIF core and the shell manganese have different valence states and functions. The core Mn is divalent Mn in the ZIF framework. 2+ The shell Mn is tetravalent MnO2.

[0050] Step (1): Synthesis of bimetallic Zn / Mn-ZIF Zinc nitrate and manganese chloride were used as metal sources. 0.119 g (0.4 mmol) of Zn(NO3)2·6H2O and 0.119 g (0.6 mmol) of MnCl2·4H2O were weighed and dissolved in 20 mL of methanol; 1.64 g of 2-methylimidazole was dissolved in 20 mL of methanol. The reaction was carried out at 25 °C under nitrogen protection for 3 hours. A light brown product, Zn / Mn-ZIF (molar ratio approximately 4:6), with a particle size of approximately 78 nm, was obtained.

[0051] Step (2): Load curcumin, the same as step (2) in Example 1, with a curcumin loading of about 11.6 wt%.

[0052] Step (3): Coat with MnO2 shell, as in Step (3) of Example 1, to obtain Cur@Zn / Mn-ZIF@MnO2. The MnO2 shell thickness is about 11 nm, and the hydrated particle size is about 128 nm.

[0053] Example 8: Comparative Example

[0054] To highlight the beneficial effects of the technical solution of the present invention, the following comparative examples are provided.

[0055] Comparative Example 1: Curcumin@single-metal ZIF-8@MnO2 (Co-free) 2+ ) In step (1), the bimetallic salt was replaced with only 0.298 g (1.0 mmol) of Zn(NO3)2·6H2O, without the addition of any cobalt salt. All other steps were exactly the same as in Example 1. The resulting product was designated Cur@ZIF-8@MnO2, with a particle size of approximately 90 nm and a shell thickness of approximately 11 nm. XPS detected only Zn and no Co signal.

[0056] Comparative Example 2: Curcumin@single-metal ZIF-67@MnO2 (Zn-free) 2+ ) In step (1), the bimetallic salt was replaced with only 0.291 g (1.0 mmol) of Co(NO3)2·6H2O, without adding any zinc salt. The remaining steps were the same as in Example 1. The resulting product was designated Cur@ZIF-67@MnO2, with a particle size of approximately 80 nm and a shell thickness of approximately 13 nm.

[0057] Comparative Example 3: Curcumin@Zn / Co-ZIF (without MnO2 shell) Only steps (1) and (2) of Example 1 were performed, without the MnO2 shell coating in step (3). The resulting product was Cur@Zn / Co-ZIF-1:1 with a particle size of approximately 88 nm.

[0058] Comparative Example 4: Curcumin @ Zn / Co + MnO2 via physical mixing method The Zn / Co-ZIF-1:1 (drug-free) prepared in Example 1 was directly and physically mixed with pre-synthesized MnO2 nanoparticles (synthesized separately from KMnO4 and dopamine under the same conditions) at a mass ratio of 1:0.3, and then curcumin was added for co-adsorption. This comparative example does not have a core-shell structure.

[0059] Comparative Example 5: Single-metal core dual-drug delivery (Cur@ZIF-8+Co) 2+ (physical adsorption) The Cur@ZIF-8@MnO2 prepared in Comparative Example 1 was immersed in a CoCl2 solution to adsorb trace amounts of Co. 2+ Within the pores of the MnO2 shell, after washing and drying. In this comparative example, Co... 2+ It is not derived from atomic-level dispersion of a bimetallic framework, but only from physical adsorption, denoted as Cur@ZIF-8@MnO2 / Co(ads).

[0060] Example 9: Performance Test Case Experimental Example 1: Microscopic Morphology and Structural Characterization The embodiments were characterized using high-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS).

[0061] TEM results: The product of Example 1 exhibits a monodisperse spherical core-shell structure with a core diameter of approximately 85 nm and a uniform shell thickness of approximately 12 nm. The shell thickness of Example 2 is significantly increased to approximately 20 nm, while the shell thickness of Example 3 is relatively thin, approximately 6 nm. This indicates that the shell thickness can be precisely controlled by adjusting the ratio of dopamine to KMnO4, with a controllable range from 5 nm to 40 nm.

[0062] STEM-EDS elemental surface scanning, taking Example 1 as an example: Zn element signals are concentrated in the core region, Mn and O element signals are distributed in a ring shape in the shell region, and Co element signals are mainly distributed in the core region and highly overlap with Zn signals, confirming the formation of a clear core-shell structure with bimetallic ZIF as the core and MnO2 as the shell, and the two metal components are spatially ordered rather than uniformly mixed.

[0063] X-ray diffraction (XRD) analysis: Examples 1-3 retained the characteristic diffraction peaks of bimetallic ZIF at the corresponding diffraction angles, and broadened characteristic peaks of MnO2 appeared near 2θ≈12°, 37°, and 66° (corresponding to the (001), (11-2), and (31-2) crystal planes of δ-MnO2), confirming that the MnO2 shell is a layered structure of naphthoic mineral.

[0064] XPS valence state analysis, taking Example 1 as an example: In the Mn 2p spectrum, the Mn 2p3 / 2 peak is located at 642.1 eV, the Mn 2p1 / 2 peak is located at 653.8 eV, and the spin-orbit splitting energy is 11.7 eV, confirming that the shell Mn mainly exists as MnO2 (Mn 4+ Co2p exists in the form of Co. The Co2p spectrum shows that the core Co mainly exists as Co. 2+ It exists in form.

[0065] Experimental Example 2: Comparison of Drug Loading Performance and Encapsulation Efficiency The drug loading content (DLC) and encapsulation efficiency (EE) of the herbal monomers in each example and comparative example were determined using a UV-Vis spectrophotometer or HPLC. The results are summarized in Table 1.

[0066]

[0067] As can be seen from Table 1: (1) The drug loading and encapsulation efficiency of bimetallic ZIF are generally better than those of monometallic ZIF, i.e., Comparative Examples 1 and 2. This shows that by introducing a second metal ion, the size of the framework pores and the surface chemical properties can be controlled, thereby enhancing the affinity with drug molecules; (2) After encapsulating the MnO2 shell, i.e. Example 1 and Comparative Example 3, the drug loading is slightly reduced because the shell increases the mass, but the encapsulation efficiency remains at a high level, indicating that the shell effectively prevents the leakage of drugs during the washing process.

[0068] Experimental Example 3: Responsive Degradation and Drug Release Behavior The degradation and release behavior of the material was investigated using dialysis under different simulated physiological conditions. Condition A (normal physiological environment): pH 7.4 phosphate buffer containing 5 mM glucose.

[0069] Condition B (Tumor extracellular microenvironment): pH 6.5 phosphate buffer containing 100 μM H2O2.

[0070] Condition C (tumor intracellular lysosome / endosome environment): pH 5.0 acetate buffer containing 10 mM H2O2.

[0071] Condition D (high reducing environment in tumor cells): pH 5.0, containing 10 mM H2O2 + 10 mM glutathione (GSH).

[0072] The materials from Example 1 were placed into dialysis bags (MWCO 3500 Da), 5 mg per bag, and immersed in the corresponding condition buffer solution, then incubated at 37 °C with shaking. Samples were taken periodically, and the released Mn was determined by ICP-OES. 2+ and Co2+ Concentration was determined using UV-Vis or HPLC for curcumin concentration.

[0073] result: Condition A (normal physiological, 24 hours): Mn 2+ Cumulative release rate <8%, Co 2+ <5%, Cur<12%. This indicates that the material is stable under normal physiological conditions and can effectively prevent premature leakage of drugs in the systemic circulation.

[0074] Condition B (tumor microenvironment, 8 hours): Mn 2+ Release rate reached 52%, Cur release rate 65%, Co 2+ The release rate was 28%, indicating that the outer shell initially responded to the weak acidity and H2O2, initiating degradation and releasing the drug.

[0075] Condition C (strong intracellular stimulation, 8 hours): Mn 2+ The release rate quickly reached 88%, Cur release rate was 92%, and Co 2+ The release rate was 65%. This indicates that once the drug enters the highly acidic, high-H2O2 environment of the intracellular lysosome, the MnO2 shell rapidly disintegrates, exposing and deeply degrading the bimetallic core, resulting in almost complete drug release. The release curve exhibits a clear "cascade response" characteristic—first a rapid response from the shell, followed by sustained release from the core.

[0076] Condition D (High reduction environment, 8 hours): Compared with condition C, Co 2+ The release rate was further increased to 85%, resulting in a more complete release of total ions. This is because GSH can accelerate the breaking of coordination bonds in the bimetallic framework through reduction. Simultaneously, the consumption of GSH provides favorable conditions for chemokinetic therapy, namely, reducing the antioxidant capacity of tumor cells.

[0077] Experimental Example 4: Verification of Magnetic Resonance Imaging Performance and Feedback Mechanism After the materials of Examples 1-3 and Comparative Examples 1-3 were incubated under different conditions, the longitudinal relaxation rate (r1) and T1-weighted imaging signal were measured using a 1.5 T clinical MRI scanner and a 0.5 T small animal MRI imaging system.

[0078] (1) In vitro MRI performance: The material from Example 1 (concentration gradients based on Mn content: 0, 0.05, 0.1, 0.2, 0.5, 1.0 mM) was dispersed in Condition C buffer and incubated for 2 hours before MRI scanning. The results showed that the brightness of the T1-weighted images significantly increased with increasing Mn concentration. The r1 value was 6.8 mM. -1 s -1 The concentration was significantly higher than that of the clinically commonly used gadopentetate dimeglumine (Gd-DTPA, r1≈4.5 mM).-1 s -1 ) and the same material without H2O2 pretreatment (r1≈0.9 mM) -1 s -1 This confirms that MnO2 degrades and releases Mn under tumor microenvironment conditions. 2+ After that, the MRI imaging capability is "activated", exhibiting excellent "off-on" response characteristics.

[0079] (2) Quantitative verification of the feedback mechanism: The material from Example 1 (0.5 mg / mL) was dispersed in condition B, and (a) Mn was simultaneously measured at different time points (0, 0.5, 1, 2, 4, 8, 12, 24 hours). 2+ (a) Cumulative release rate, (b) cumulative release rate of curcumin, and (c) percentage increase in T1-weighted MRI signal intensity (ΔSNR%). Pearson correlation analysis showed that ΔSNR% was correlated with Mn. 2+ Linear correlation coefficient R of release rate 2 =0.982, ΔSNR% and R of Cur release rate 2 =0.956. This indicates that changes in MRI signal intensity can accurately reflect the degree of material degradation and the drug release process, constituting a highly reliable real-time "imaging feedback mechanism".

[0080] (3) In vivo MRI imaging in small animals: Establish a BALB / c nude mouse subcutaneous 4T1 breast cancer xenograft model (tumor volume approximately 150-200 mm). 3 The materials of Example 1 or Comparative Example 3 were injected via tail vein (dose: 10 mg / kg body weight, n=3 per group). T1-weighted MRI scans were performed before injection and at 0.5, 1, 2, 4, 8, and 24 hours after injection.

[0081] Example 1: One hour after injection, the T1 signal at the tumor site began to increase; it reached its peak at 4 hours, with a signal intensity increase of approximately 185%, and the tumor outline was clear and bright in the MRI image. The signal slowly decreased after 24 hours, but remained discernible. This dynamic signal change directly reflects the enrichment of the material at the tumor site, the degradation of MnO2, and the increase of Mn... 2+ The entire release process enables real-time monitoring and feedback of the treatment process.

[0082] Comparative group 3 (without MnO2 shell, without Mn): The MRI signal of the tumor area did not change significantly before and after injection (<5%), and could not provide any imaging feedback information.

[0083] Example 5: Evaluation of the synergistic chemokinetic therapeutic performance of bimetallic drugs (1) Hydroxyl radical (·OH) generation ability: The ability to catalyze the generation of ·OH was evaluated using the methylene blue (MB) degradation method. Materials from Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 4 (each containing an equal amount of metal ions, 25 μg / mL) were incubated with MB (10 μg / mL) and H₂O₂ (100 μM), respectively, in pH 6.0 buffer for 30 minutes. The rate of decrease in absorbance of MB at 665 nm was measured.

[0084] Example 1 (Zn / Co bimetal + MnO2): MB degradation rate reached 86.5%.

[0085] Comparative Example 1 (Zn monometal + MnO2 only): MB degradation rate 46.2%.

[0086] Comparative Example 2 (Co monometal only + MnO2): MB degradation rate 58.7%.

[0087] Comparative Example 4 (physical mixture of Zn / Co and MnO2): MB degradation rate 63.1%.

[0088] Comparative Example 5 (Physical Adsorption of Co) 2+ (In the shell): MB degradation rate 55.3%.

[0089] Further verification by electron spin resonance (ESR) showed that, under the same conditions, the signal intensity (quartet, 1:2:2:1) of the DMPO-·OH adduct generated in Example 1 was significantly higher than that of the comparative examples, with the integral intensity being 4.8 times that of Comparative Example 1 and 3.2 times that of Comparative Example 2.

[0090] The above results indicate that Co is atomically dispersed in the bimetallic core. 2+ Mn released from the shell 2+ A highly efficient and synergistic Fenton-like catalytic system was formed, with a ·OH yield far exceeding that of single metal systems or physically mixed systems. This is because Co 2+ / Mn 2 + Electron transfer between bimetals can be accelerated through redox cycles of different valence states, which greatly improves catalytic efficiency.

[0091] (2) Glutathione consumption capacity: Each material was incubated with GSH (1 mM) at pH 5.0, and the GSH consumption rate was determined using Ellman's reagent. Example 1 consumed approximately 72% of the GSH within 4 hours, while Comparative Example 1 consumed only 35%. 2+ The introduction of can effectively oxidize GSH, reduce the inherent antioxidant defense capacity of tumor cells, and further amplify the cytotoxic effect of ·OH.

[0092] Experimental Example 6: Cellular Uptake and Intracellular Reactive Oxygen Species (ROS) Detection Human breast cancer MCF-7 cells and doxorubicin-resistant MCF-7 / ADR cells were used as models.

[0093] (1) Cell uptake: FITC-labeled materials (50 μg / mL) were incubated with MCF-7 cells for 4 hours, and the fluorescence intensity was detected by flow cytometry. The cell uptake in Example 1 was 1.6 times that of Comparative Example 1 (monometallic ZIF-8) and 1.4 times that of Comparative Example 2 (monometallic ZIF-67), indicating that the suitable particle size and surface properties of bimetallic ZIFs are more conducive to tumor cell uptake.

[0094] (2) Intracellular ROS detection: Cells were labeled with the DCFH-DA probe, and flow cytometry analysis was performed 4 hours after each material treatment. The intracellular ROS level in the treatment group of Example 1 was 6.8 times that of the control group, 3.5 times that of Comparative Example 1, 4.1 times that of Comparative Example 2, 1.8 times that of Comparative Example 3 (without MnO2), and 4.5 times that of Comparative Example 5. This result is highly consistent with the ·OH generation experiment, confirming that the bimetallic system still maintains a synergistic catalytic advantage intracellularly.

[0095] Trial Example 7: In vitro cytotoxicity and combined therapy index The standard MTT and CCK-8 assays were used to evaluate the 48-hour cytotoxicity of various materials against MCF-7 cells (human breast cancer), HepG2 cells (human liver cancer), and MCF-7 / ADR-resistant cells. Results were expressed as IC50. 50 (Half-maximal inhibitory concentration) is expressed as (half-maximal inhibitory concentration).

[0096] Table 2 IC50 of MCF-7 cells in each embodiment and comparative embodiment 50 Value (48 hours)

[0097] The Chou-Talalay method was used to calculate the drug combination index (CI), where CI < 1 indicates synergy, CI = 1 indicates addition, and CI > 1 indicates antagonism.

[0098] Taking Example 1 as an example, the CI value for the combination of chemotherapy and chemokinetics was 0.38 (in IC50). 50 The CI values ​​were much lower than 1, indicating strong synergy. The CI for Comparative Example 1 was 0.72, and for Comparative Example 2 it was 0.58, both showing weaker synergistic effects than the bimetallic system. The CI for Comparative Example 3 (without chemokinetic therapeutic components) could not be calculated (it was only chemotherapy alone). The CI for Example 6 (dual-drug co-loading) was even lower, at 0.28, indicating a more pronounced synergistic advantage between the multiple components of traditional Chinese medicine and chemokinetic therapy.

[0099] For drug-resistant MCF-7 / ADR cells, the IC50 of Example 1 50The concentration was 5.8 μg / mL (resistance index RI = 1.38), while the IC50 of free curcumin was... 50 The concentration of up to 68.4 μg / mL (RI=2.70) indicates that this nanodelivery system can effectively overcome tumor drug resistance.

[0100] Experimental Example 10: Double Staining of Live and Dead Cells and Detection of Apoptosis MCF-7 cells were treated with Example 1, Comparative Examples 1-5, and free drugs for 24 hours, respectively, and then stained with Calcein-AM / PI double staining kit and observed under a fluorescence microscope. Example 1 group showed extensive red fluorescence (dead cells) and very little green fluorescence (live cells). The area and intensity of red fluorescence in each of the comparative examples were significantly less than in Example 1.

[0101] Annexin V-FITC / PI double staining flow cytometry apoptosis quantitative analysis showed that the total apoptosis rate (early + late) in the Example 1 treatment group was 68.5%, compared to 35.2% in Comparative Example 1, 42.8% in Comparative Example 2, 18.6% in Comparative Example 3 (without MnO2), and only 12.3% in the free curcumin group. This indicates that bimetallic chemokinetics combined with chemotherapy can significantly promote tumor cell apoptosis.

[0102] Experimental Example 11: In vivo antitumor efficacy A BALB / c nude mouse subcutaneous 4T1 breast cancer model was established and randomly divided into 7 groups (n=6 per group): (1) saline control group; (2) blank Zn / Co-ZIF@MnO2 carrier (no drug); (3) free curcumin; (4) Comparative Example 3 Cur@Zn / Co-ZIF (no MnO2); (5) Comparative Example 1 Cur@ZIF-8@MnO2; (6) Example 1 Cur@Zn / Co-ZIF@MnO2; (7) Example 5 PEG-modified Rg3@Zn / Co-ZIF@MnO2-PEG. The drugs were administered via tail vein injection once every 3 days for a total of 4 times (days 0, 3, 6, and 9), at a dose of 5 mg / kg body weight based on curcumin content.

[0103] result: After 14 days of treatment, the tumor volume in the saline group increased approximately 12-fold.

[0104] The tumor inhibition rate of the free curcumin group was only about 28%.

[0105] The tumor inhibition rate of Comparative Example 3 (chemotherapy only, without chemokinetics) was approximately 45%.

[0106] Comparative Example 1 (monometallic chemokinetics + chemotherapy) showed a tumor inhibition rate of approximately 62%.

[0107] Example 1 (bimetallic synergistic chemokinetic therapy + chemotherapy) showed a tumor inhibition rate of up to 85%, with the most extensive areas of apoptosis (TUNEL staining) and necrosis in the tumor tissue, and the lowest Ki-67 proliferation index.

[0108] Example 5 (PEG modified) showed a further tumor inhibition rate of 90%, which may be related to prolonged in vivo circulation time and increased tumor accumulation.

[0109] In the MCF-7 / ADR resistant tumor model, the tumor inhibition rate of Example 1 still reached 72%, while free curcumin had almost no effect (tumor inhibition rate <10%), further confirming the effectiveness of the system against drug-resistant tumors.

[0110] Example 12: Preliminary evaluation of in vivo safety During the treatment period, the mice in each group did not experience a significant decrease in body weight (fluctuation <8%), and their food and water intake and activity remained normal. At the experimental endpoint, major organs (heart, liver, spleen, lung, and kidney) were collected for H&E staining. No obvious histopathological abnormalities, inflammatory infiltration, or necrotic foci were observed in any of the treatment groups. Serum biochemical indicators (ALT, AST, BUN, Cr) in Group 1 were all within the normal range, with no statistically significant differences compared to the control group. ICP-MS measurements of Zn, Co, and Mn in each organ and whole blood showed that Zn mainly accumulated in the tumor and liver 24 hours after administration, and most of it was excreted in urine and feces after 72 hours, with low residual levels and no risk of long-term accumulation.

[0111] Example 1 (Cur@Zn / Co-ZIF-1:1@MnO2) showed superior and balanced performance across evaluation dimensions including structural integrity, particle size uniformity, drug loading-encapsulation balance, cascade response sensitivity, MRI imaging feedback, synergistic effect of chemokinetics, and in vivo tumor inhibition rate.

[0112] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0113] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An antitumor bimetallic nanomaterial, characterized in that: It includes, from the inside out, the drug components, the bimetallic core, and the functional outer shell; The bimetallic framework core is a bimetallic doped zeolite imidazole ester framework material, which uses two different transition metal ions as coordination nodes and self-assembles with imidazole organic ligands through coordination bonds to form a three-dimensional porous framework structure. The functional outer shell is a manganese dioxide shell layer that is in situ coated on the outer surface of the bimetallic skeleton core; The drug component is an anti-tumor traditional Chinese medicine active monomer loaded in the internal pores of the bimetallic framework core; Specifically, it is a zinc-cobalt bimetallic zeolite imidazole ester framework loaded with curcumin and coated with manganese dioxide core-shell nanocomposite material (Cur@ZnCo-ZIF@MnO2).

2. A method for preparing an antitumor bimetallic nanomaterial, characterized in that: Includes the following steps: (1) Synthesis of bimetallic zeolite imidazole ester framework (ZIF) nanoparticles: The first metal salt, the second metal salt and 2-methylimidazolium are mixed in a solvent and a coordination reaction is carried out to generate bimetallic ZIF nanoparticles containing the first metal ion and the second metal ion. (2) Loading Chinese medicine monomers: The bimetallic ZIF nanoparticles are dispersed in a solution containing Chinese medicine monomers, and the Chinese medicine monomers are loaded into the pores of the bimetallic ZIF nanoparticles by stirring to obtain drug-loaded bimetallic ZIF nanoparticles. (3) Coating with a manganese dioxide shell: The drug-loaded bimetallic ZIF nanoparticles are dispersed in an alkaline buffer solution. Dopamine monomer and potassium permanganate solution are added sequentially under stirring. The potassium permanganate is reduced by the in-situ polymerization reaction of dopamine, thereby forming a manganese dioxide shell on the surface of the drug-loaded bimetallic ZIF nanoparticles. After solid-liquid separation, washing and drying, the antitumor bimetallic nano-organic material is obtained.

3. The method for preparing antitumor bimetallic nano-organic materials as described in claim 2, characterized in that: In step (1), the first metal salt is a zinc salt and the second metal salt is a cobalt salt; the molar ratio of the first metal salt to the second metal salt is (1:10)-(10:1); the particle size of the bimetallic ZIF nanoparticles is 30-200 nm.

4. The method for preparing antitumor bimetallic nano-organic materials as described in claim 3, characterized in that: In step (1), the zinc salt is zinc nitrate, zinc acetate or their hydrate; the cobalt salt is cobalt nitrate, cobalt acetate or their hydrate; the solvent is methanol or water; the temperature of the coordination reaction is 20-30 ℃ and the reaction time is 1-6 hours.

5. The method for preparing the antitumor bimetallic nano-organic material as described in claim 4, characterized in that: In step (2), the herbal monomer is selected from at least one of curcumin, berberine, tripterygium oleracea, gambogeylic acid, and ginsenoside Rg3; the concentration of the herbal monomer in the solution is 0.2-5 mg / mL; the mass ratio of the bimetallic ZIF nanoparticles to the herbal monomer is 1:(0.1-1.5), and the stirring loading time is 8-24 hours.

6. The method for preparing antitumor bimetallic nano-organic materials as described in claim 5, characterized in that: In step (3), the alkaline buffer solution is a tris(hydroxymethyl)aminomethane hydrochloride buffer solution with a pH of 8.0 to 9.0; the dopamine is dopamine hydrochloride; the mass ratio of the drug-loaded bimetallic ZIF nanoparticles to dopamine hydrochloride is 1:(0.5-2); the mass ratio of potassium permanganate to dopamine hydrochloride is (0.5-2):1; the reaction time for forming the manganese dioxide shell is 1-6 hours, and the reaction temperature is 15-35 ℃.

7. The method for preparing antitumor bimetallic nano-organic materials as described in claim 6, characterized in that: The material has a core-shell structure, with its core being bimetallic zeolite imidazole ester framework nanoparticles loaded with traditional Chinese medicine monomers, and its shell being a manganese dioxide layer wrapped around the outer surface of the core. The coordination structure of the bimetallic zeolite imidazole ester framework nanoparticles simultaneously contains a first metal ion and a second metal ion, which together constitute the bimetallic active component of the organic material.

8. The method for preparing the antitumor bimetallic nano-organic material as described in claim 7, characterized in that: The first metal ion is Zn 2+ The second metal ion is Co. 2+ Zn 2+ With Co 2+ The molar ratio is (1:5) - (5:1); The herbal monomers are selected from at least one of curcumin, berberine, tripterygium oleracea, gambogeylic acid, and ginsenoside Rg3; The material has an average hydrated particle size of 80-250 nm, wherein the thickness of the manganese dioxide shell is 5-40 nm.

9. The method for preparing the antitumor bimetallic nano-organic material as described in claim 8, characterized in that: The material degrades under acidic and high hydrogen peroxide conditions simulating a tumor microenvironment, releasing Co. 2+ Mn 2+ Ions and the aforementioned traditional Chinese medicine monomers; The released Mn 2+ Ions, used as contrast agents in T1-weighted magnetic resonance imaging, generate real-time imaging signals that reflect the drug delivery and release process. Simultaneously, the changes in the intensity of these imaging signals are positively correlated with material degradation and the degree of drug release, forming a feedback mechanism for real-time monitoring of the treatment process. The released Mn 2+ Ions and Co 2+ Ions synergistically catalyze the generation of cytotoxic hydroxyl radicals from hydrogen peroxide within tumor cells, achieving enhanced chemokinetic therapy. Combined with the chemotherapeutic effects of the aforementioned traditional Chinese medicine monomers, this produces a synergistic antitumor effect.

10. Application of antitumor bimetallic nano-organic materials in the preparation of magnetic resonance imaging-mediated tumor combination therapy agents, wherein the combination therapy includes T1-weighted magnetic resonance imaging, enhanced chemokinetic therapy, and chemotherapy.

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