PAMAM-based mitochondrial targeting iron chelating nano-platform as well as preparation method and application thereof

Abstract

The invention discloses a PAMAM (polyamidoamine)-based mitochondrial targeting iron chelating nano-platform as well as a preparation method and application thereof. The PAMAM-based mitochondrial targeting iron chelating nano-platform is prepared according to the following method: (1) purifying PAMAM through dialysis, and freeze-drying for later use; (2) taking maltol and benzyl chloride as raw materials to synthesize 3-(benzyloxy)-2-methyl-4-pyrone; and purifying and drying to obtain the 3-(benzyloxy)-2-methyl-4-pyrone. (3) inoculating the 3-(benzyloxy)-2-methyl-4-pyrone into the PAMAM (Polyamidoamine); (4) carrying out catalytic hydrogenation on a product obtained by inoculating the 3-(benzyloxy)-2-methyl-4-pyrone into the PAMAM to remove a benzyl protecting group so as to obtain DFP-PAMAM; and (5) inoculating the DFP-PAMAM with triphenylphosphine-polyethylene glycol-succinimide, carrying out dialysis purification, and then carrying out freeze drying so as to obtain the DFP-PAMAM-TPP. The nano platform enters cells in an endocytosis mode, the drug uptake rate is increased, mitochondrial dysfunction is effectively relieved, the mitochondrial iron steady state is maintained, and therefore diseases related to granulocyte iron overload are treated.

Description

Technical Field

[0001] The present invention relates to the technical field of medical materials, and in particular to a mitochondrial-targeted iron chelating nano-platform based on PAMAM, and a preparation method and application thereof. Background Art

[0002] Iron is an essential trace element for cell growth, development and maintenance of cell homeostasis. 3+ ) and reduced ferrous iron (Fe 2+ ) forms to transfer electrons, so it is a key component involved in the electron transport chain within mitochondria, DNA repair and replication, chromatin remodeling and epigenetic changes, and cellular metabolism. In biological systems, iron can be incorporated into iron-sulfur clusters (e.g., mitochondrial aconitase, coenzyme Q10, respiratory complexes I-III) and heme molecules (e.g., myoglobin, hemoglobin, myeloperoxidase, cytochrome proteins, nitric oxide synthase). Both of these iron-containing structures are cofactors for many enzymes and are partially synthesized within the mitochondria, making them the central organelles for cellular iron metabolism. At the same time, iron is the most prevalent metal in the mitochondrial matrix, which helps promote the complex redox chemistry of the electron transport chain. Among them, the unique redox properties of iron allow efficient electron transfer while generating reactive oxygen species (ROS). Therefore, insufficient or excessive mitochondrial iron levels can lead to mitochondrial dysfunction and cause oxidative stress, which affects the mitochondrial production of ATP through tricarboxylic acid (TCA) and / or glycolysis.

[0003] Mitochondrial iron homeostasis imbalance can further lead to the occurrence and development of diseases. Among them, diffuse iron accumulation exists in the cerebral cortex and hippocampus of patients with Alzheimer's disease (AD), and the iron content in senile plaques is slightly increased. Specifically, in AD, iron accumulation induces oxidative stress, lipid peroxidation and inflammatory response by destroying mitochondrial function, consuming ATP and inducing ROS production. The combined effects of oxidative stress, lipid peroxidation and neuroinflammation lead to the occurrence of AD. Several studies have provided strong evidence for the correlation between iron homeostasis disorder and obesity and diabetes. The iron concentration in the liver and adipose tissue of obese people is higher. Iron accumulation increases ROS through the Fenton reaction, leading to mitochondrial dysfunction in adipocytes. This toxic effect on β cells can lead to defects in insulin synthesis and secretion. Hyperglycemia exacerbates iron accumulation and promotes oxidative stress and the development of type 2 diabetes. In addition, in cardiovascular diseases, heart failure is caused by changes in mitochondrial iron homeostasis and mitochondrial function. Excessive iron can lead to impaired vascular function and aggravate atherosclerosis, arrhythmias and heart failure. Excess iron can also catalyze the production of ROS, which can lead to lipid peroxidation and organelle damage, further leading to cardiomyocyte death and fibrosis, and ultimately to impaired systolic and diastolic function. The observation that mitochondrial iron levels are elevated in patients with heart failure supports this theory. The above studies show that mitochondrial iron metabolism disorders are the basis of the pathogenesis of many diseases. Specifically, mitochondrial iron overload can lead to dysfunctional mitochondrial synthesis of heme and / or ISCs, leading to mitochondrial dysfunction and subsequent oxidative damage. This may lead to further downstream signaling that induces various diseases. Therefore, highly precise and effective targeted regulation of mitochondrial iron homeostasis can open up new ideas and strategies with great potential for the treatment of a variety of complex diseases.

[0004] At present, the treatment methods for diseases caused by iron overload are mainly focused on iron chelators. Iron chelators are drugs used to treat iron overload, which can effectively reduce the content of excess iron in the body and reduce the toxic effects of iron on organs under pathological conditions such as AD, obesity, diabetes and cardiovascular diseases. Currently, common iron chelators in clinical practice include: deferoxamine (DFO), deferiprone (DFP) and deferasirox (DFS). However, most of the iron chelators in the prior art have problems such as poor targeting, low bioavailability, and insufficient in vivo stability, making it difficult to achieve accurate and efficient targeted delivery and therapeutic effects. Therefore, there is an urgent need to develop a new mitochondrial-targeted iron chelation nanoplatform to overcome the shortcomings of the prior art and provide a new solution for the treatment of diseases related to mitochondrial iron overload. Summary of the invention

[0005] In order to solve the above technical problems, the first purpose of the present invention is to provide a method for preparing a mitochondrial targeted iron chelating nano-platform based on PAMAM, the second purpose is to provide the mitochondrial targeted iron chelating nano-platform based on PAMAM, and the third purpose is to provide its application. The present invention constructs a mitochondrial targeted iron chelating nano-material (DFP-PAMAM-TPP, DPT) which inhibits mitochondrial iron overload and alleviates mitochondrial dysfunction by targeting mitochondria, thereby providing a unique nano-therapeutic solution for the treatment of diseases related to mitochondrial iron overload.

[0006] To achieve the above objectives, the present invention is implemented by the following technical scheme: a method for preparing a mitochondrial-targeted iron chelating nanoplatform based on PAMAM, characterized in that the preparation is carried out according to the following steps:

[0007] (1) polyamidoamine dendrimer (PAMAM) was purified by dialysis and freeze-dried for later use;

[0008] (2) synthesizing 3-(benzyloxy)-2-methyl-4-pyrone using maltol and benzyl chloride as raw materials; purifying and drying to obtain 3-(benzyloxy)-2-methyl-4-pyrone;

[0009] (3) 3-(Benzyloxy)-2-methyl-4-pyrone accessed PAMAM;

[0010] (4) 3-(benzyloxy)-2-methyl-4-pyrone is connected to PAMAM and the product is catalytically hydrogenated to remove the benzyl protecting group to obtain DFP-PAMAM;

[0011] (5) DFP-PAMAM-TPP can be obtained by connecting triphenylphosphine-polyethylene glycol-succinimide to DFP-PAMAM, dialysis purification and freeze drying. DFP-PAMAM-TPP is referred to as DPT.

[0012] In the above scheme: the polyamidoamine dendrimer is an amino-terminated fourth-generation polyamidoamine dendrimer, the molecular formula of which is C 622 H 1248 N 250 O 124 The fourth generation PAMAM (NH 2 - ) Molecular weight: 14215 In the above scheme: In step (1), the polyamidoamine dendrimer is dissolved in ultrapure water and dialyzed in ultrapure water using a dialysis bag with a molecular weight cutoff of 3500Da, and the water is changed every 4 hours to purify PAMAM.

[0013] After dialysis, the ultrapure aqueous solution of PAMAM was precooled at -20°C for 2 hours, pre-frozen at -80°C for 12 hours, placed in a -80°C freeze dryer for freeze drying, and then PAMAM was stored at -20°C.

[0014] In the above scheme: the specific operation of step (2) is: prepare a sodium hydroxide methanol solution with a methanol solution, add maltol to the sodium hydroxide methanol solution; then add an excess of benzyl chloride to the above solution, reflux reaction until the reaction is complete, evaporate the solvent, and then add water to the residue; extract the aqueous phase with dichloromethane, wash the organic phase with a NaOH solution first, and then with deionized water to remove sodium hydroxide and other soluble salt impurities, dry the organic phase with anhydrous sodium sulfate and filter, and then distill to remove the solvent to obtain the product. The mass concentration of methanol is 90%, and the mass concentration of sodium hydroxide in the sodium hydroxide methanol solution is 4-5%. Benzyl chloride is slightly excessive, and the molar ratio of maltol to benzyl chloride is preferably 1:1-1.1. During extraction, dichloromethane is used for extraction 2-3 times, and the extraction is as complete as possible. The organic phase is washed 2-3 times with a sodium hydroxide solution with a mass concentration of about 5%, and washed 2-3 times with deionized water.

[0015] In the above scheme: the operation of step (3) is: 3-(benzyloxy) 2-methyl-4-pyrone and PAMAM are mixed in ultrapure water, the mixture is stirred at 70-80°C to react until the reaction is complete, and then the reaction solution is extracted with dichloromethane to ensure that the target product is transferred from the aqueous phase to the organic phase, the organic phases are combined and dried with anhydrous sodium sulfate, and then the dichloromethane is distilled off, and the target product is purified by silica gel column chromatography, and the eluent is a mixture of chloroform and methanol in a volume ratio of 1:1. The molar ratio of 3-(benzyloxy) 2-methyl-4-pyrone to PAMAM is 80:1.

[0016] In the above scheme, the operation of step (4) is as follows: the product is mixed with a catalytic amount of a Pd / C catalyst in ethanol for reaction, placed in an autoclave, the autoclave is sealed, the air in the autoclave is replaced with nitrogen first, and then the nitrogen is replaced with hydrogen, and the process is repeated three times, the hydrogen pressure is raised to 0.1-0.2 MPa, stirring is started, and the benzyl protecting group in 3-(benzyloxy)-2-methyl-4-pyrone is removed; after the reaction is completed, the catalyst is removed by filtration, and the solvent is evaporated to obtain DFP-PAMAM.

[0017] In the above scheme: the operation of step (5) is: dissolving DFP-PAMAM and triphenylphosphine-polyethylene glycol-succinimide in a PBS buffer at a molar ratio of 1:20, stirring and reacting at room temperature in the dark, and then dialyzing the mixed solution in ultrapure water with a molecular weight cutoff of 3500Da, changing the water every 4 hours to remove unreacted triphenylphosphine-polyethylene glycol-succinimide, and obtaining a pure product DFP-PAMAM-TPP; freeze-drying to obtain DFP-PAMAM-TPP, and storing DFP-PAMAM-TPP at -20°C. The freeze-drying step is: pre-cooling at -20°C for 2h, pre-freezing at -80°C for 12h, drying in a -80°C freeze dryer, and storing DFP-PAMAM-TPP at -20°C.

[0018] A preparation method of a mitochondrial targeted iron chelating nano-platform based on PAMAM is prepared. The present invention is a novel mitochondrial iron targeting nano-platform constructed for diseases related to mitochondrial iron overload and defects of current iron chelators. The nano-platform is composed of the fourth generation of amino-terminal polyamidoamine dendritic molecules (PAMAM.G4) to form the platform body, providing good modifiable performance. Deferiprone analogs are synthesized using maltol as a precursor and covalently bonded to the PAMAM molecule as an iron chelating component. Triphenylphosphine-polyethylene glycol-succinimide (TPP-PEG-NHS) is used as a mitochondrial targeting unit, and HNS is covalently bonded to PAMAM by an amidation reaction with the primary amine at the end of PAMAM. The nano-platform enters the cell in an endocytic manner, increases the drug uptake rate, and effectively alleviates mitochondrial dysfunction, maintains mitochondrial iron homeostasis, and thus treats diseases related to mitochondrial iron overload.

[0019] A use of the PAMAM-based mitochondrial-targeted iron chelating nanoplatform in the preparation of drugs for treating diseases related to mitochondrial iron overload.

[0020] The mitochondrial targeted iron chelating nanomaterial DPT exhibits excellent mitochondrial targeting and iron chelating capabilities, effectively regulates mitochondrial iron homeostasis, and restores mitochondrial function. Compared with the non-targeted iron chelator DFP, DPT significantly restores mitochondrial function.

[0021] The diseases associated with mitochondrial iron overload are cardiovascular diseases or neurodegenerative diseases or muscular atrophy or liver diseases. The cardiovascular diseases are atherosclerosis, arrhythmia and heart failure; the neurodegenerative diseases are Alzheimer's disease and Parkinson's disease.

[0022] The main polyamidoamine dendritic molecule of the nano-platform of the present invention adopts the fourth generation polyamidoamine dendritic molecule (PAMAM.G4, -NH 2The mitochondrial targeting group is triphenylphosphine-polyethylene glycol-succinimide (TPP-PEG-NHS), the iron chelating component is 1,2-dimethyl-3-hydroxy-4-pyridone as well as amide groups and primary amine groups, and the amino-terminal fourth-generation polyamidoamine (PAMAM.G4, -NH 2 ) is composed of a core, a polymer main chain and side chains of branch units. It is a monodisperse polymer with a highly branched structure, a cavity structure, and active functional groups enriched on the surface, and controllable physical and chemical properties. In the present invention, the mitochondrial targeted iron chelating nanoplatform main body, the iron chelating group position is as follows Figure 1 As shown. Figure 1 As shown, the inner core is an amino-terminated fourth-generation polyamidoamine dendrimer, and the outer layer is a modified triphenylphosphine-polyethylene glycol-succinimide group and a deferoxamine analog (DFP).

[0023] A mitochondrial-targeted iron-chelating nanoplatform includes PAMAM covalently linked to DFP

[0024] (DFP-PAMAM) and TPP-PEG-NHS, the number of DFP on PAMAM is (1 to 64) and the molar ratio of DFP-PAMAM to TPP-PEG-NHS is 1:20. Within this ratio range, DFP is covalently linked to the PAMAM molecule as an iron chelating component. Triphenylphosphine-polyethylene glycol-succinimide (TPP-PEG-NHS) is covalently bound to PAMAM through an amidation reaction between NHS and the primary amine at the end of PAMAM, providing a mitochondrial targeting unit.

[0025] The mitochondrial targeted iron chelating nano-platform prepared by the present invention has a particle size of about 8 nm and a negative charge on the surface. Figure 2 shown.

[0026] The DPT nanoparticles provided by the present invention can restore the GPX4 protein downregulated by cigarette smoke extract (CSE) and enhance the synthesis of ferritin. In this way, it helps to prevent free iron ions from being free in cells, thereby reducing the generation of free radicals catalyzed by iron and lipid peroxidation. DPT nanoparticles effectively improve the accumulation of iron ions in the periosteum and effectively alleviate CSE-induced ferroptosis. Therefore, the mitochondrial targeted iron chelation nanoplatform provided by the present invention as described above can be used to prepare drugs for the treatment of mitochondrial iron overload diseases, and the factors include: mitochondrial diseases, such as maternally inherited Leigh syndrome, mitochondrial myopathy, progressive ophthalmoplegia, Leber hereditary optic neuropathy, etc.; neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's syndrome (PD), Friedreich's ataxia (FRDA), etc.; other diseases, such as mitochondrial dysfunction caused by smoking, etc.

[0027] The mitochondrial targeted iron chelation nanoplatform provided by the present invention can significantly restore mitochondrial membrane potential, reduce the level of reactive oxygen species in mitochondria, effectively regulate mitochondrial iron homeostasis, and restore mitochondrial function by targeted chelation of mitochondrial overload iron. It is expected to overcome the problem of mitochondrial targeting and achieve long-term and safe drug administration treatment.

[0028] There is no particular limitation on the drug administration of the mitochondrial targeted iron chelating nanoplatform prepared by the present invention. Representative administration methods include (but are not limited to): oral, rectal, parenteral (intravenous, intramuscular or subcutaneous), and local administration.

[0029] The present invention has the following beneficial effects:

[0030] (1) Compared with traditional drugs and existing treatment methods, the mitochondrial targeted iron chelating nanoplatform provided by the present invention has a simple preparation method, is easy to operate, and has low cost;

[0031] (2) Precise targeting of drugs to organelles can reduce toxic side effects and improve bioavailability. The mitochondrial targeted iron chelating nanoplatform provided by the present invention can precisely target mitochondria and reduce toxic side effects.

[0032] (3) The higher the loading amount of the chelating agent, the lower the dosage of the conjugate, and the smaller the burden of elimination. The mitochondrial targeted iron chelating nanoplatform provided by the present invention has a higher iron chelating efficiency.

[0033] (4) The mitochondrial targeted iron chelating nanoplatform provided by the present invention can restore the GPX4 protein downregulated by CSE and enhance the synthesis of ferritin. It keeps the iron ions stable in a non-toxic form, thereby helping to prevent free iron ions from being free in the cell, thereby reducing the generation of iron-catalyzed free radicals and lipid peroxidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the synthesis route of DFP-PAMAM-TPP.

[0035] Figure 2 To measure the particle size distribution and zeta potential of PAMAM, DFP-PAMAM and DFP-PAMAM-TPP using DLS.

[0036] Figure 3 TEM observation and statistical analysis of DFP-PAMAM and DFP-PAMAM-TPP. (A) Morphology observed by transmission electron microscopy. (B) Statistical analysis of transmission electron microscopy. (C) Detection of elements in DFP-PAMAM-TPP using energy dispersive X-ray spectroscopy (EDS).

[0037] Figure 4 1H-NMR and FTIR spectra of PAMAM, DFP, DFP-PAMAM, NHS-PEG-TPP and DFP-PAMAM-TPP.

[0038] Figure 5 The detection of DFP-PAMAM-TPP's targeting ability to mitochondria and its ability to chelate iron ions. A is the detection of DPT co-localization with mitochondria, and BC is the detection of the material's ability to chelate iron in cells.

[0039] Figure 6 DFP-PAMAM-TPP alleviates mitochondrial dysfunction caused by cigarette smoke extract (CSE). A uses mitoferrogreen probe to detect mitochondrial iron ions. B uses JC-1 probe to detect mitochondrial membrane potential. CD uses mitoSOX probe to detect mitochondrial superoxide anions

[0040] Figure 7 Immunofluorescence staining of osteogenic markers (OCN) and ferroptosis markers (GPX4) in calvarial bone defects. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] Example 1 A mitochondrial-targeted iron chelating nanoplatform based on PAMAM was prepared according to the following steps:

[0043] 1) The amino-terminated fourth-generation polyamidoamine dendrimer PAMAM (NH2-), C622H1248N250O124, molecular weight: 14215, was dissolved in ultrapure water, and dialyzed in ultrapure water for 24 hours using a dialysis bag with a molecular weight cutoff of 3500Da to purify PAMAM, and the water was changed every 4 hours. After dialysis, the PAMAM solution was transferred to an EP tube, pre-cooled at -20°C for 2 hours, pre-frozen at -80°C for 12 hours, and freeze-dried in a -80°C freeze dryer, and then stored at -20°C.

[0044] 2) Synthesis of 3-(benzyloxy)-2-methyl-4-pyrone: Sodium hydroxide was dissolved in 35 mL of 90% methanol solution to a concentration of 4.4%, and maltol (4.00 g, 32 mmol) was added to the methanol NaOH solution. Benzyl chloride (4.42 g, 35 mmol) was then added to the above solution. The mixture was refluxed and mixed for 6 hours. The solvent was then removed by rotary evaporation, and 16 mL of water was then added to the residue. The aqueous phase was washed three times with 12 mL of dichloromethane. The organic phases were combined and washed twice with 16 mL (5% w / v) NaOH, and then washed twice with 16 mL of deionized water. The organic phase was dried over anhydrous sodium sulfate and filtered, and then the solvent was distilled off to obtain the product.

[0045] 3) 3-(Benzyloxy)-2-methyl-4-pyrone (17.32 g, 80 mmol) and PAMAM (14.215 g, 1 mmol) were mixed in 200 mL of ultrapure water, and the mixture was stirred at 70-80°C for 24 hours. After the reaction, the reaction solution was extracted twice with dichloromethane (1000 mL). The organic phases were combined and dried over anhydrous sodium sulfate, and then distilled to remove dichloromethane. The target product was purified by silica gel column chromatography, and the eluent was chloroform and methanol in a volume ratio of 1:1. The product and a catalytic amount of Pd / C catalyst are mixed in ethanol for reaction, placed in an autoclave, the autoclave is sealed, the air in the autoclave is replaced with nitrogen first, and then the nitrogen is replaced with hydrogen, and the process is repeated three times. The hydrogen pressure is increased to 0.1-0.2 MPa, stirring is started, and the reaction is started to remove the benzyl protecting group in 3-(benzyloxy)-2-methyl-4-pyrone; after the reaction is completed (reaction for 4 days), the catalyst is removed by filtration, and the solvent is evaporated to obtain DFP-PAMAM.

[0046] 4) Dissolve DFP-PAMAM and triphenylphosphine-polyethylene glycol-succinimide (TPP-PEG-NHS) in an appropriate amount of PBS buffer solution at a molar ratio of 1:20, and react with stirring at room temperature in the dark for 24 hours. The mixed solution was dialyzed in ultrapure water for 24 hours with a molecular weight cutoff of 3500Da to remove unreacted TPP-PEG-NHS, and the water was replaced every 4 hours. After freeze drying (precooling at -20°C for 2 hours, prefreezing at -80°C for 12 hours, and drying and freezing in a -80°C freeze dryer), DFP-PAMAM-TPP (DPT) was obtained and stored at -20°C.

[0047] Application Example 2:

[0048] The DPT prepared in Example 1 was selected as a mitochondrial targeted iron chelator to alleviate mitochondrial iron overload. Figure 2 To measure the particle size distribution and zeta potential of PAMAM, DFP-PAMAM and DFP-PAMAM-TPP using DLS, Figure 2 It can be seen that the selected DPT has a regular morphology and uniform particle size, with an average particle size of about 8 nm. DFP is loaded on the surface of PAMAM by covalent cross-linking, such as Figure 2 As shown in the figure, the Zeta potential of the modified DFP-PAMAM changes from +3mV to 16mV, proving that the DFP targeting group is successfully loaded on the PAMAM surface. Figure 3 , Figure 4 (TEM, 1 H-NMR and FTIR) showed that TPP was covalently bound to PAMAM through amidation reaction between HNS and the primary amine at the end of PAMAM. DFP-PAMAM and DFP-PAMAM-TPP nanoparticles were labeled with FITC and incubated with cells for 24 hours. Figure 5 As shown, the mitochondrial targeting ability of the nanoparticles was significantly enhanced after the introduction of TPP molecules, and DFP-PAMAM-TPP could restore the iron overload caused by ferric ammonium citrate (FAC).

[0049] like Figure 6 As shown, by selecting the MC3T3-E1 cell research model. Using Mitoferrogreen probe to detect changes in mitochondrial iron ions, DPT nanoparticles significantly improved CSE-induced mitochondrial iron overload, mitochondrial membrane potential detection showed that DPT nanoparticles significantly restored the decrease in membrane potential caused by CSE, and the detection of mitochondrial superoxide using mitoSOX probe also showed similar results, and DPT nanoparticles significantly improved the production of mitochondrial reactive oxygen species, indicating that the mitochondrial targeted iron chelating nanoplatform of the present invention can significantly reduce CSE-induced mitochondrial iron overload and relieve cellular oxidative stress.

[0050] DFP-PAMAM-TPP nanoparticles were loaded with hydrogel and implanted into the skull bone defect of tobacco-exposed mice. Figure 7 As shown, DPT was found to alleviate the loss of GPX4 caused by CSE, inhibited ferroptosis, and increased the level of osteocalcin (OCN).

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a mitochondrial-targeted iron chelating nanoplatform based on PAMAM, characterized in that: Prepare according to the following steps: (1) polyamidoamine dendrimer (PAMAM) was purified by dialysis and freeze-dried for later use; (2) synthesizing 3-(benzyloxy)-2-methyl-4-pyrone using maltol and benzyl chloride as raw materials; purifying and drying to obtain 3-(benzyloxy)-2-methyl-4-pyrone; (3) 3-(Benzyloxy)-2-methyl-4-pyrone accessed PAMAM; (4) 3-(benzyloxy)-2-methyl-4-pyrone is connected to PAMAM and the product is catalytically hydrogenated to remove the benzyl protecting group to obtain DFP-PAMAM; (5) DFP-PAMAM-TPP can be obtained by connecting triphenylphosphine-polyethylene glycol-succinimide to DFP-PAMAM, dialysis purification, and freeze-drying.

2. The method for preparing the mitochondrial-targeted iron chelating nanoplatform based on PAMAM according to claim 1, characterized in that: The polyamidoamine dendrimer is an amino-terminated fourth-generation polyamidoamine dendrimer, and the molecular formula is C 622 H 1248 N 250 O 124 .

3. The method for preparing the mitochondrial-targeted iron chelating nanoplatform based on PAMAM according to claim 1 or 2, characterized in that: In step (1), the polyamidoamine dendrimer is dissolved in ultrapure water, and dialyzed in ultrapure water using a dialysis bag with a molecular weight cutoff of 3500 Da, with the water being changed every 4 hours to purify the PAMAM.

4. The method for preparing the mitochondrial-targeted iron chelating nanoplatform based on PAMAM according to claim 3, characterized in that: The specific operation of step (2) is as follows: preparing a sodium hydroxide methanol solution with a methanol solution, adding maltol to the sodium hydroxide methanol solution; then adding an excess of benzyl chloride to the above solution, reflux reaction until the reaction is complete, distilling off the solvent, and then adding water to the residue; extracting the aqueous phase with dichloromethane, washing the organic phase with a NaOH solution first, and then washing with deionized water to remove sodium hydroxide and other soluble salt impurities, drying the organic phase over anhydrous sodium sulfate and filtering, and then distilling off the solvent to obtain the product.

5. The method for preparing the mitochondrial-targeted iron chelating nanoplatform based on PAMAM according to claim 4, characterized in that: The operation of step (3) is as follows: 3-(benzyloxy)-2-methyl-4-pyrone and PAMAM are mixed in ultrapure water, the mixture is stirred at 70-80° C. to react until the reaction is complete, and then the reaction solution is extracted with dichloromethane to ensure that the target product is transferred from the aqueous phase to the organic phase, the organic phases are combined and dried with anhydrous sodium sulfate, and then the dichloromethane is distilled off, and the target product is purified by silica gel column chromatography, and the eluent is a mixture of chloroform and methanol in a volume ratio of 1:

1.

6. The method for preparing the mitochondrial-targeted iron chelating nanoplatform based on PAMAM according to claim 5, characterized in that: The operation of step (4) is as follows: the product is mixed with a catalytic amount of a Pd / C catalyst in ethanol for reaction, placed in an autoclave, hydrogen is introduced, and the reaction is performed to remove the benzyl protecting group in 3-(benzyloxy)-2-methyl-4-pyrone; after the reaction is completed, the catalyst is removed by filtration, and the solvent is evaporated to obtain DFP-PAMAM.

7. The method for preparing the mitochondrial-targeted iron chelating nanoplatform based on PAMAM according to claim 6, characterized in that: The operation of step (5) is as follows: DFP-PAMAM and triphenylphosphine-polyethylene glycol-succinimide are dissolved in PBS buffer at a molar ratio of 1:20, stirred and reacted at room temperature in the dark, and then the mixed solution is dialyzed in ultrapure water with a molecular weight cutoff of 3500Da, and the water is replaced every 4 hours to remove unreacted triphenylphosphine-polyethylene glycol-succinimide to obtain a pure product DFP-PAMAM-TPP; DFP-PAMAM-TPP is obtained by freeze drying, and DFP-PAMAM-TPP is stored at -20°C. 8 . A PAMAM-based mitochondrial targeted iron chelating nanoplatform prepared by the method for preparing the PAMAM-based mitochondrial targeted iron chelating nanoplatform according to any one of claims 1 to 7 .

9. Use of the PAMAM-based mitochondrial-targeted iron chelating nanoplatform according to claim 8 in the preparation of drugs for treating diseases related to mitochondrial iron overload.

10. The use according to claim 9, characterized in that: The diseases associated with mitochondrial iron overload are cardiovascular diseases or neurodegenerative diseases or muscular atrophy or liver diseases. The cardiovascular diseases are atherosclerosis, arrhythmia and heart failure; the neurodegenerative diseases are Alzheimer's disease and Parkinson's disease.

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