Nanogel for targeting cardiac radioactive injury as well as preparation method and application of nanogel

Abstract

The invention belongs to the technical field of drug carrier preparation, and discloses a cardiac radiation injury targeting nanogel which comprises a composite delivery carrier and circNCX1 plasmids coupled with the composite delivery carrier, wherein the composite delivery carrier is prepared from pegylated sodium oxide alginate, myocardial targeting peptide and cell penetrating peptide; the PEGylated sodium oxide alginate is obtained by carrying out amino reaction on oxidized sodium alginate and polyethylene glycol monomethyl ether. The nanogel can accurately deliver circNCX1 plasmids to heart tissues, reduces myocardial cell apoptosis, can improve the stability, targeting and cellular uptake ability of the circNCX1 plasmids in the in-vivo delivery process, realizes a heart protection effect, and can be used for preventing coronary diseases, myocardial ischemia, ischemia reperfusion injury, arrhythmia and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of drug carrier preparation, and particularly relates to a nanogel targeting radiation-induced heart injury, a preparation method thereof, and an application thereof. Background Art

[0002] Radiation-Induced Heart Disease (RIHD) is one of the common and serious complications after tumor radiotherapy. With the progress of modern radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT) and proton radiotherapy (PT), the risk of radiation injury has decreased to some extent. However, for patients receiving treatment for thoracic malignancies, the heart is inevitably exposed to radiation, leading to a series of cardiovascular diseases, such as coronary heart disease, pericarditis, cardiomyopathy, and arrhythmia. Existing studies have shown that these radiation-induced heart injuries usually appear several years after treatment, significantly affecting the quality of life of survivors.

[0003] Currently, the clinical treatment methods for RIHD mainly include: (1) a drug symptomatic treatment system, such as ACE inhibitors, β-blockers, antioxidants, etc., which are used to relieve abnormal heart function; (2) radiotherapy dose optimization and distribution regulation, such as using three-dimensional conformal radiotherapy and other techniques to reduce the heart irradiation dose. However, these methods only alleviate symptoms or the risk of radiation injury to a certain extent, and cannot fundamentally prevent the occurrence of heart injury or reverse myocardial damage.

[0004] In terms of drug delivery, the application of nanotechnology provides new ideas for the treatment of RIHD. The nanodelivery system can deliver drugs to the damaged myocardial region through targeted design, avoiding systemic side effects. However, currently commonly used nanodelivery systems (such as liposomes, polymer nanoparticles) still have problems such as low targeting efficiency, uncontrollable drug release, and fast in vivo metabolism. In addition, the complex pathological mechanisms of radiation-induced heart injury, including inflammatory response, oxidative stress, and cardiomyocyte apoptosis, further increase the challenges of precision treatment. Summary of the Invention

[0005] The purpose of the present invention is to provide a nanogel that can target radiation-induced heart injury and achieve controlled release.

[0006] The first aspect of the present invention provides a nanogel targeting radiation-induced heart injury, and the nanogel includes a composite delivery carrier and a circNCX1 plasmid coupled to the composite delivery carrier;

[0007] Among them, the composite delivery carrier is prepared from polyethylene glycolated sodium alginate, a myocardial targeting peptide, and a cell-penetrating peptide; the polyethylene glycolated sodium alginate is obtained by reacting oxidized sodium alginate with polyethylene glycol monomethyl ether amine.

[0008] In some of these embodiments, the ratio of the composite delivery carrier to the circNCX1 plasmid is 0.1 mg to 50 mg: 0.1 μg to 1000 μg, preferably 1 mg to 20 mg: 10 μg to 100 μg, more preferably 1 mg to 10 mg: 15 μg to 25 μg, and further preferably 5 mg: 15 μg to 25 μg.

[0009] In some of these embodiments, the mass ratio of the polyethylene glycolated sodium alginate, the myocardial targeting peptide, and the cell-penetrating peptide is 0.1 to 50: 0.01 to 10: 0.01 to 10; preferably, the mass ratio of the polyethylene glycolated sodium alginate, the myocardial targeting peptide, and the cell-penetrating peptide is 1 to 20: 1 to 10: 1 to 10; more preferably, the mass ratio of the polyethylene glycolated sodium alginate, the myocardial targeting peptide, and the cell-penetrating peptide is 5 to 10: 1 to 5: 1 to 5; further preferably, the mass ratio of the polyethylene glycolated sodium alginate, the myocardial targeting peptide, and the cell-penetrating peptide is 5 to 6: 1 to 2: 1 to 2; and / or,

[0010] The molar ratio of the oxidized sodium alginate to the methoxypolyethylene glycol amine is 1: 1 to 50, preferably 1: 1 to 20, further preferably 1: 1: 10, and more preferably 1: 1 to 5.

[0011] In some of these embodiments, the method for preparing the composite delivery carrier comprises the following steps:

[0012] (1) Reacting the polyethylene glycolated sodium alginate with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide to obtain a mixed solution;

[0013] (2) Reacting the obtained mixed solution with the myocardial targeting peptide and the cell-penetrating peptide to obtain a reaction product;

[0014] (3) Lyophilizing the obtained reaction product to obtain the composite delivery carrier;

[0015] Preferably, in step (2), the pH value of the reaction system is 4 to 8, preferably 5 to 6; and / or,

[0016] In step (2), the reaction temperature is 0 °C to 50 °C, and the reaction time is 1 h to 48 h; and / or,

[0017] In step (1), the mass ratio of the polyethylene glycolated sodium alginate to 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide is 1: 1 to 5: 1 to 5; and / or,

[0018] In step (1), the reaction time is 20 min to 30 min.

[0019] In some of these embodiments, the method for preparing the polyethylene glycolated sodium alginate comprises the following steps:

[0020] (a) Oxidizing sodium alginate to obtain oxidized sodium alginate;

[0021] (b) Performing an amidation reaction on the oxidized sodium alginate, methoxypolyethylene glycol amine, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, and N-hydroxysuccinimide to obtain the polyethylene glycolated sodium alginate.

[0022] In some of these embodiments, in step (b), the pH value of the reaction system is 3 to 9; and / or,

[0023] In step (b), the reaction temperature is 0°C to 50°C, and the reaction time is 1 h to 48 h.

[0024] In some of these embodiments, the method for preparing the oxidized sodium alginate comprises the following steps:

[0025] Reacting sodium alginate with a sodium periodate solution to obtain a reaction product;

[0026] Precipitating the obtained reaction product with ethanol to obtain the oxidized sodium alginate;

[0027] Preferably, the mass ratio of the sodium alginate to the sodium periodate is 0.1 to 10:0.2 to 20, preferably 1 to 10:1 to 10, more preferably 3:1 to 5; and / or,

[0028] The concentration of the sodium periodate solution is 0.01 g / mL to 1 g / mL, preferably 0.1 g / mL to 0.5 g / mL, more preferably 0.1 g / mL to 0.2 g / mL; and / or,

[0029] In the reaction system of the reaction between the sodium alginate and the sodium periodate solution, the reaction temperature is 0 to 50°C, and the reaction time is 1 h to 72 h;

[0030] In the step of precipitating the obtained reaction product with ethanol, the reaction temperature is -10°C to 10°C.

[0031] In some of these embodiments, the amino acid sequence of the myocardial targeting peptide is as shown in SEQ ID NO: 1; and / or,

[0032] The amino acid sequence of the cell-penetrating peptide is as shown in SEQ ID NO: 2; and / or,

[0033] The nucleotide sequence of the circNCX1 plasmid is as shown in SEQ ID NO: 3.

[0034] The second aspect of the present invention provides an application of the above-mentioned nanogel targeting cardiac radiation injury in the preparation of a drug for preventing and / or treating cardiac radiation injury.

[0035] The third aspect of the present invention provides a preparation method of a nanogel targeting cardiac radiation injury, and the preparation method includes the following steps:

[0036] Dissolve the composite delivery carrier and the circNCX1 plasmid in water, and then dropwise add them into a CaCl2 solution for reaction to obtain the nanogel;

[0037] Preferably, the concentration of the CaCl2 solution is 0.1 mM to 100 mM, preferably 1 mM to 10 mM, more preferably 4 mM to 5 mM; the ratio of the composite delivery carrier, the circNCX1 plasmid, water and the CaCl2 solution is 0.1 mg to 50 mg: 0.1 μg to 1000 μg: 1 mL to 5 mL: 1 mL to 5 mL, preferably 1 mg to 10 mg: 15 μg to 25 μg: 1 mL: 2 mL; and / or,

[0038] The pH value of the reaction is 4 to 9; and / or,

[0039] The temperature of the reaction is 0 °C to 50 °C, and the reaction time is 1 h to 72 h.

[0040] In the present invention, amide reaction is carried out between oxidized sodium alginate and methoxypolyethylene glycol amine to obtain polyethylene glycolated sodium alginate, and then the polyethylene glycolated sodium alginate is used to prepare a composite delivery carrier with TAT and PCM. A new nanogel is prepared by using the composite delivery carrier and the circNCX1 plasmid. It is found that the nanogel can accurately deliver the circNCX1 plasmid to the heart tissue, reduce cardiomyocyte apoptosis caused by cardiac radiation injury, and can improve the stability, targeting and cell uptake ability of the circNCX1 plasmid during in vivo delivery, realizing a heart protection effect, and can be used for the prevention and treatment of cardiac radiation injury, and can also be used for the prevention and treatment of other complications such as coronary artery disease, myocardial ischemia, ischemia-reperfusion injury, arrhythmia, etc.

[0041] Furthermore, the present invention also finds that by optimizing the synthesis conditions of oxidized sodium alginate and polyethylene glycolated sodium alginate and combining with modified peptide molecules, the particle size of the nanogel can be precisely controlled at about 150 nm, avoiding the precipitation problem caused by too large particles. Description of the Drawings

[0042] Figure 1 It is a plasmid map of the circNCX1 (has_circ_0005232) expression plasmid.

[0043] Figure 2 A is the TEM image of circNCX1 nanogel, scale bar: 100 nm; Figure 2 B is the hydrodynamic diameter of circNCX1 nanogel in aqueous solution; Figure 2 C - Figure 2 D is the absorption result graph of AC16 cells to circNCX1 nanogel detected by flow cytometry; Figure 2 E is the encapsulation efficiency of different concentrations of mPEG - OSA - PCM - TAT nanogel on circNCX1 plasmid.

[0044] Figure 3 is the absorption efficiency result graph of AC16 cells to circNCX1 plasmid and circNCX1 nanogel.

[0045] Figure 4 is the plasmid map of circNCX1 (has_circ_0005232) expression plasmid.

[0046] Figure 5 A - Figure 5 B is the cumulative amount of circNCX1 nanogel in different organs.

[0047] Figure 6 A is the HE staining result graph of mice after radiation with different treatment methods; Figure 6 B is the Masson pathological section staining graph of mice after radiation with different treatment methods; Figure 6 C is the serum CK - MB level result graph of mice after radiation with different treatment methods; Figure 6 D is the serum cTn - I level result graph of mice after radiation with different treatment methods; Figure 6 E is the Masson staining result graph of the heart tissue of mice after radiation with different treatment methods. Detailed implementation manners

[0048] For the convenience of understanding the present invention, the present invention will be described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosed content of the present invention more thorough and comprehensive.

[0049] The experimental methods without specific conditions noted in the following examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturers. All kinds of common chemical reagents used in the examples are commercially available products.

[0050] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the technical field to which the present invention pertains. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0051] The following describes the solution of the present invention in conjunction with specific embodiments.

[0052] Among them, in the following embodiments:

[0053] The sequence of PCM (SEQ ID NO: 1) is: WLSEAGPVVTVRALRGTGSW.

[0054] The sequence of TAT (SEQ ID NO: 2) is: YGRKKRRQRRR.

[0055] The sequence of has_circ_0005232 (SEQ ID NO: 3) is:

[0056]

[0057] mmu_circ_0000823 (SEQ ID NO: 4):

[0058]

[0059] Example 1

[0060] This example provides a method for preparing a nanogel targeting cardiac radiation injury, which includes the following steps:

[0061] 1.1 Preparation of sodium alginate oxide (OSA)

[0062] First, dissolve sodium alginate (3.00 g) in 280 mL of deionized water at room temperature. Then, drop 20 mL of sodium periodate aqueous solution (0.13 g / mL) into the sodium alginate solution and stir at room temperature for 12 hours to synthesize OSA. Precipitate with 100% pure ethanol at 4°C and separate the product. The obtained OSA precipitate is centrifuged (10,000 rpm, 10 minutes), and then washed three times with ethanol to obtain purified OSA.

[0063] 1.2 Synthesis of methoxypolyethylene glycol - sodium alginate oxide (mPEG - OSA)

[0064] Add the prepared OSA (0.1 g, 0.505 mmol of alginic acid units), 1 - ethyl - 3 - (3 - dimethylaminopropyl) - carbodiimide (EDC, 20 mg), N - hydroxysuccinimide (NHS, 20 mg), and methoxypolyethylene glycol monoamine (mPEG - NH2, molecular weight 2000, Ponsure Biological) (0.101 g, 0.0505 mmol, relative content to alginic acid units in OSA is 10 mol%) into deionized water (7 mL, pH = 5.5), and then react at room temperature for 24 hours to synthesize mPEG - OSA.

[0065] Then, first remove the unreacted OSA by ethanol precipitation method, and then dissolve the obtained mPEG - OSA in ethanol. Finally, dialyze with a dialysis membrane (cut - off molecular weight 3500 Da) in deionized water for 48 hours to remove the unreacted mPEG - NH2, and then lyophilize to obtain purified mPEG - OSA.

[0066] 1.3 Synthesis of target - modified mPEG - OSA - PCM - TAT

[0067] Dissolve the prepared mPEG-OSA (5 mg) in 3 ml of phosphate buffer solution. Add EDC (5 mg) and NHS (5 mg) under magnetic stirring to activate the carboxyl group. After 30 min, add the polypeptide mixture of PCM (SEQ ID NO.1, 1 mg) and TAT (SEQ ID NO.2, 1 mg). Adjust the pH of the solution to 5.5 and stir the reaction at room temperature for 12 h. Dialyze the reaction product against a dialysis bag (MWCO 10,000 Da) for 48 h, and finally freeze-dry to obtain mPEG-OSA-PCM-TAT, which is the composite delivery carrier.

[0068] 1.4 Preparation of circNCX1@mPEG-OSA-PCM-TAT Nanogel

[0069] Dissolve 5 mg of the prepared mPEG-OSA-PCM-TAT and 20 μg of the circNCX1 expression plasmid (has_circ_0005232, SEQ ID NO.3), and the map of this circNCX1 expression plasmid is as Figure 1 shown, in 1 mL of ultrapure water, and adjust the pH to 8.0. Then slowly drop it into 2 mL of CaCl2 solution (5 mM, pH = 6) and stir the reaction at room temperature for 12 h. The reaction product is separated by centrifugation, and washed and centrifuged with ultrapure water three times repeatedly. The final precipitate obtained is the circNCX1@mPEG-OSA-PCM-TAT nanogel.

[0070] Example 2 Structural Characteristics of circNCX1@mPEG-OSA-PCM-TAT Nanogel

[0071] Slowly add the circNCX1@mPEG-OSA-PCM-TAT nanogel (abbreviated as circNCX1 nanogel) prepared in Example 1 to ultrapure water (Milli-Q grade) to prepare an aqueous solution with a concentration of 1 mg / ml. Briefly centrifuge at low speed (3000 rpm, 3 min) to remove air bubbles, and then measure the hydrodynamic diameter three times at 25 °C by a dynamic light scattering instrument ( Figure 2 B), and the particle size of the circNCX1@

[0072] mPEG-OSA-PCM-TAT nanogel is 150 nm - 500 nm, and most of them are concentrated around 150 nm.

[0073] Take 10 μL of the sample and drop it onto a carbon film copper grid. After negative staining with 2% phosphotungstic acid for 1 minute, observe the morphology and take images using a transmission electron microscope at 80 kV. The results are as Figure 2 shown in A, and nanogels with clear boundaries can be obtained.

[0074] AC16 cells (purchased from Guangzhou Peiyu Biotechnology Co., Ltd., donor is male) were seeded into six-well plates at 3×10 5 cells per well with 2 mL of medium per well. After culturing for 24 hours, circNCX1 plasmid and circNCX1 nanogel (8 μg circNCX1 plasmid) were added into the wells and cultured at 37 °C for 4 hours. After trypsinization, the cells were rinsed three times with cold PBS and resuspended in 500 μL PBS, and then the circNCX1 signal was detected by flow cytometry. Analysis was performed using FlowJo version 10.0 software. As shown in Figure 2 C and Figure 2 D, the content of FITC-labeled substances inside AC16 cells increased, indicating that circNCX1 nanogel was more effectively taken up by cells compared to the circNCX1 plasmid group (plasmid group) and the Control group (control group).

[0075] According to the preparation method of Example 1, mPEG-OSA-PCM-TAT nanogels with different concentrations (10 μg, 20 μg, 40 μg, 80 μg, and 100 μg) were added, and the encapsulation efficiency of the circNCX1 plasmid was detected. The results are shown in Figure 2 E, and good encapsulation efficiency could be maintained at different encapsulation concentrations.

[0076] Example 3 Detection of the absorption efficiency of AC16 cells for circNCX1 nanogel

[0077] AC16 cells were seeded onto Lab-Tek chamber slides for 48 hours, and then the circNCX1 plasmid and the circNCX1 nanogel prepared in Example 1 were added to the chamber slides and incubated with AC16 cells at 37 °C for 6 hours.

[0078] After rinsing with PBS, the cells were fixed with 4% paraformaldehyde and stained with DAPI or GFP, and the expression of DAPI and GFP was observed after 48 hours. The absorption efficiency of AC16 cells for the circNCX1 plasmid and the circNCX1 nanogel was observed using a confocal microscope (Zeiss LSM 710, Germany). The results are shown in Figure 3 , and the circNCX1 nanogel showed more effective intracellular localization, with a more uniform and extensive distribution pattern compared to the circNCX1 plasmid.

[0079] Example 4 Targeted cardiac effect of circNCX1 nanogel in mice

[0080] Prepare circNCX1 nanogels according to the preparation method of Example 1, wherein the nucleotide sequence of the circNCX1 plasmid (mmu_circ_0000823) is shown in SEQ ID NO.4, and the plasmid map of circNCX1 is as Figure 4 shown.

[0081] Add 10 mg of circNCX1 nanogels, 50 μg of Sulfo-Cy7 amine, 5 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and 5 mg of N-hydroxysuccinimide (NHS) to 1.5 ml of deionized water. After the reaction, dialyze in deionized water for 48 hours using a dialysis membrane with a molecular weight cut-off (MWCO) of 3500 Da to remove unreacted Sulfo-Cy7 amine. Then lyophilize the final product.

[0082] Intravenously inject C57 mice (n = 21) via the tail vein with Cy7, mPEG-OSA-Cy7 and mPEG-OSA-PCM-TAT-Cy7 at a concentration of 0.05 mg / kg. At different time points after injection (1, 2, 4, 8, 12, 24 and 48 hours), remove the main organs (heart, liver, spleen, lung and kidney), observe the Cy7 fluorescence signal using an IVIS imaging system, evaluate its distribution, and compare the relative cumulative amount. The results are as Figure 5 A and Figure 5 shown in B. Compared with the Cy7 and mPEG-OSA-Cy7 groups, the nanogels modified with mPEG-OSA-PCM-TAT showed significantly higher cardiac accumulation 1 hour after administration.

[0083] Example 5 Protective effect of circNCX1 nanogels on the hearts of mice under radiation conditions

[0084] The mice selected for the cardiac radiation injury model constructed in this example were 8-week-old male C57BL / 6 mice. Anesthetize the mice with a certain amount of sodium pentobarbital according to their body weight, and remove the hair on the chest of the mice before irradiation. After the mice were completely anesthetized, immediately place them flat on a special lead block, and the lead block covered other parts of the mice, only exposing the heart part for targeted irradiation of the heart. The irradiation conditions were 20 Gy of X-rays with a dose rate of 1 Gy / minute.

[0085] Thirty-six 8-week-old male C57BL / 6 mice were randomly divided into 6 groups of 6 mice each, and injected via the tail vein. The first group was injected with a certain amount of normal saline only. The second group was irradiated after injection of a certain amount of normal saline. The third group was irradiated after injection of a certain amount of mPEG-OSA-PCM-TAT (20 μg / each). The fourth group was irradiated after injection of a certain amount of circNCX1 plasmid (20 μg / each). The fifth group was irradiated after injection of a certain amount of circNCX1@mPEG-OSA-PCM-TAT nanogel (20 μg / each). The sixth group was injected with a certain amount of circNCX1@

[0086] mPEG-OSA-PCM-TAT nanomedicine gel (20 μg / each). The mice treated as above were housed in the animal house according to the groups, and the condition of the mice was observed daily. Fresh drinking water, mouse food and bedding were changed for the mice every week, and the cages were cleaned to keep the cages clean and tidy.

[0087] After 12 weeks of treatment, the mice were dissected at the cervical vertebra. After dissection, the hearts of the mice were perfused. After perfusion was completed, the hearts of the mice were isolated, rinsed with PBS, and subjected to HE staining and Masson pathological section staining. Mouse CK-MB and cTn-I enzyme-linked immunosorbent assay kits (FineTest, EM0929, EM1466) were used to measure the serum CK-MB and cTn-I levels. And Masson staining was performed on the heart tissues of the six groups of mice.

[0088] As Figure 6 A- Figure 6 B shows, hematoxylin and eosin (H&E) staining showed that in the IR-saline group pretreated with normal saline before irradiation, the boundaries of myocardial bundles were significantly dissolved and the cardiac cavity volume increased, indicating severe myocardial disorder and dilation. In contrast, in the IR-nanogel group pretreated with circNCX1@mPEG-OSA-PCM-TAT nanogel before irradiation, myocardial dilation and boundary dissolution were minimal, indicating strong resistance to radiation-induced damage. The IR-circNCX1@mPEG-OSA-PCM-TAT nanogel group showed a moderate degree of protection after irradiation, while the pre-IR carrier and pre-IR plasmid groups showed varying degrees of myocardial protection, and there was no obvious pathological difference between the pre-IR plasmid group and the pre-IR saline group.

[0089] Two cardiac injury biomarkers, CK-MB and cTn-I, were used to evaluate myocardial injury at different sensitivity thresholds. As Figure 6 C shows, compared with the control group and the nanogel group, the levels of both markers in the mice of the pre-IR saline group were significantly increased after 12 weeks and 16 weeks. In contrast, the levels of both markers in the mice of the pre-IR nanogel group were significantly decreased.

[0090] As Figure 6 shown in E, Masson trichrome staining further indicated that fibrosis was most prominent in the saline group before IR, characterized by extensive collagen deposition, while the nano-gel group before IR showed minimal fibrosis. The nano-gel group after IR showed moderate fibrosis, the carrier group before IR showed some fibrotic changes, and the plasmid group before IR showed negligible fibrosis.

[0091] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0092] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A nanogel targeting cardiac radiation injury, characterized in that, The nanogel includes a composite delivery carrier and a circNCX1 plasmid conjugated to the composite delivery carrier; Among them, the composite delivery carrier is prepared from polyethylene glycolated sodium alginate, a myocardial targeting peptide, and a cell-penetrating peptide; the polyethylene glycolated sodium alginate is obtained by reacting oxidized sodium alginate with polyethylene glycol monomethyl ether amine.

2. The nanogel according to claim 1, characterized in that, The ratio of the composite delivery carrier to the circNCX1 plasmid is 0.1 mg to 50 mg: 0.1 μg to 1000 μg, preferably 1 mg to 20 mg: 10 μg to 100 μg, and more preferably 1 mg to 10 mg: 15 μg to 25 μg.

3. The nanogel according to claim 1, wherein The mass ratio of the polyethylene glycolated sodium alginate, the myocardial targeting peptide, and the cell-penetrating peptide is 0.1 to 50: 0.01 to 10: 0.01 to 10; preferably, the mass ratio of the polyethylene glycolated sodium alginate, the myocardial targeting peptide, and the cell-penetrating peptide is 5 to 10: 1 to 5: 1 to 5; and / or, The molar ratio of the oxidized sodium alginate to the polyethylene glycol monomethyl ether amine is 1: 1 to 50, preferably 1: 1 to 5.

4. The nanogel according to claim 1, characterized in that, The preparation method of the composite delivery carrier includes the following steps: (1) React the polyethylene glycolated sodium alginate with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide to obtain a mixed solution; (2) React the obtained mixed solution with the myocardial targeting peptide and the cell-penetrating peptide to obtain a reaction product; (3) Lyophilize the obtained reaction product to obtain the composite delivery carrier; Preferably, in step (2), the pH value of the reaction system is 4 to 8; and / or, In step (2), the reaction temperature is 0 °C to 50 °C, and the reaction time is 1 h to 48 h; and / or, In step (1), the mass ratio of the polyethylene glycolated sodium alginate to 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide is 1: 1 to 5: 1 to 5; and / or, In step (1), the reaction time is 20 min to 30 min.

5. The nanogel according to any one of claims 1-4, characterized in that, The preparation method of the polyethylene glycolated sodium alginate includes the following steps: (a) Oxidize sodium alginate to obtain oxidized sodium alginate; (b) Perform an amidation reaction on the oxidized sodium alginate, polyethylene glycol monomethyl ether amine, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, and N-hydroxysuccinimide to obtain polyethylene glycolated sodium alginate.

6. The nanogel according to claim 5, characterized in that, In step (b), the pH value of the reaction system is 3 to 9; and / or, In step (b), the reaction temperature is 0 °C to 50 °C, and the reaction time is 1 h to 48 h; and / or.

7. The nanogel according to claim 5, characterized in that, The preparation method of the oxidized sodium alginate includes the following steps: React sodium alginate with a sodium periodate solution to obtain a reaction product; Precipitate the obtained reaction product with ethanol to obtain the oxidized sodium alginate; Preferably, the mass ratio of the sodium alginate to the sodium periodate is 0.1 to 10: 0.2 to 20; and / or, The concentration of the sodium periodate solution is 0.01 g / mL to 1 g / mL; and / or, In the reaction system of sodium alginate and sodium periodate solution, the reaction temperature is 0 to 50 °C, and the reaction time is 1 h to 72 h; In the step of precipitating the reaction product with ethanol, the reaction temperature is -10 °C to 10 °C.

8. The nanogel according to claim 1, wherein The amino acid sequence of the myocardial targeting peptide is as shown in SEQ ID NO: 1; and / or, The amino acid sequence of the cell-penetrating peptide is as shown in SEQ ID NO: 2; and / or, The nucleotide sequence of the circNCX1 plasmid is as shown in SEQ ID NO:

3.

9. Use of the nanogel targeting cardiac radiation injury according to any one of claims 1-8 in the preparation of a drug for preventing and / or treating cardiac radiation injury.

10. A preparation method of a nanogel targeting cardiac radiation injury, characterized in that, The preparation method comprises the following steps: Dissolve the composite delivery vector and the circNCX1 plasmid in water, and then dropwise add the solution to a CaCl2 solution to react to obtain the nanogel; Preferably, the concentration of the CaCl2 solution is 0.1 mM to 100 mM, more preferably 1 mM to 10 mM; the ratio of the composite delivery vector, the circNCX1 plasmid, water and the CaCl2 solution is 0.1 mg to 50 mg: 0.1 μg to 1000 μg: 1 mL: 2 mL; and / or, The pH value of the reaction is 4 to 9; and / or, The reaction temperature is 0 °C to 50 °C, and the reaction time is 1 h to 72 h.

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