A radionuclide nanomedicine for targeted treatment of breast cancer, its preparation method and application

Abstract

The present invention provides a radionuclide nanomedicine for targeted treatment of breast cancer, its preparation method and application, including a calcium phosphate biomineralized nanocore labeled with the radionuclide 32P, and a metal polyphenol network nanoshell formed by Mn2+ and a polyphenol derivative modified with cRGD. The prepared core-shell nanoparticles can target and deliver 32P to breast cancer tissues, supply oxygen in situ, and achieve efficient intratumoral radionuclide brachytherapy. The preparation process is rapid and simple, the reaction process is controllable, green and environmentally friendly, without the need to add additional excipients and organic solvents, and no other impurities are introduced. Moreover, the radionuclide nanomedicine can rapidly degrade and release the drug in response to the acidic microenvironment after targeting breast cancer, avoiding the toxicity caused by the accumulation of the carrier and radionuclide in the body. It can not only relieve the hypoxia condition of breast cancer tumor tissues, but also release the therapeutic radionuclide 32P as an active ingredient to exert its efficacy. By efficient 32P targeted delivery and in-situ oxygen supply, it can effectively kill tumor cells and inhibit the growth and metastasis of primary breast cancer tumors.

Description

Technical Field

[0001] The present invention relates to the field of nano biomedicine, and particularly relates to a radionuclide nano drug for targeted treatment of breast cancer, a preparation method thereof and an application thereof. Background Art

[0002] With the rapid development of nuclear medicine, concentrating radioactive nuclides in tumor tissues to achieve internal radiotherapy has become a new radiotherapy method with broad application prospects. Researchers call this therapy internal radionuclide therapy (IRT), which uses high-energy α and β rays generated during the decay process of radioactive nuclides to irradiate and kill tumors at close range. For IRT, radioactive nuclides with appropriate half-lives and radiation energies need to be selected. Commonly used therapeutic nuclides include 32 P, 90 Y, 13 1I, 177 Lu, etc. Such nuclides have appropriate half-lives (<15 d), can form non-toxic decay products after exerting their efficacy, and the α or β rays emitted by them have a more efficient linear energy transfer than X-rays, making it easier to cause energy accumulation. However, there are also many challenges in the practical application of IRT: on the one hand, the non-specific distribution of radioactive nuclides in the body easily leads to toxic and side effects such as liver and kidney damage and bone marrow suppression; on the other hand, the tissue penetration depth of the α and β rays emitted by therapeutic nuclides is limited, and radiation blind spots are easily formed in tumor tissues, resulting in reduced efficacy and recurrence. Therefore, it is particularly important to accurately deliver radioactive nuclides to tumor tissues to cause precise killing, and the development and design of safe and efficient targeted radionuclide drugs have great clinical significance.

[0003] With the development of nanotechnology, some nanomaterials with excellent properties provide new ideas for the design of targeted radionuclide drugs. "Radionuclide nano drugs" show many advantages: 1) Nanomaterials can be used as carriers of radioactive nuclides to accurately deliver them to tumors. Nanocarriers can often be modified with active targeting ligands. For example, nanocarriers modified with cRGD can specifically recognize integrin αvβ3 overexpressed in breast cancer and target the drug to breast cancer tissues; 2) Nanomaterials can be effectively combined with the characteristics of radioactive nuclides. On the one hand, the use of a rationally designed intelligent nano delivery system can enhance the killing effect of radioactive nuclides on primary tumors and metastatic tumors. On the other hand, various effects generated during the decay process of nuclides can activate nanomaterials; 3) Through nanomaterials, the combination of IRT and other diagnosis and treatment means can be realized. Therefore, developing a radionuclide nano drug that can target and treat breast cancer has good clinical application value. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a radionuclide nanomedicine for targeted treatment of breast cancer, its preparation method and application, aiming to construct a radioactive nuclide delivery system capable of targeted treatment of breast cancer. This radionuclide nanomedicine targets and binds to integrin αvβ3 specifically expressed on tumor cells to mediate endocytosis, responds to the acidic environment of lysosomes to release drugs, and catalyzes the decomposition of high-level endogenous hydrogen peroxide to supply oxygen, enhancing the 32 DNA damage mediated by radionuclide

[0005] <000032P> 32 <000032P>-labeled calcium phosphate biomineralized nanocore, and a metal polyphenol network nanoshell formed by self-assembly of Mn 2+ and cRGD-modified polyphenol derivatives; under the regulation of catalase, the nanocore is obtained by the biomineralization reaction of 32 <000032P>-labeled phosphate ions and calcium ions.

[0006] Preferably, the cRGD-modified polyphenol derivative is dopamine-polyethylene glycol-cRGD polypeptide (DA-PEG-cRGD).

[0007] Preferably, the particle size of the radionuclide nanomedicine is 50-100 nm.

[0008] Based on a general inventive concept, the present invention also provides a preparation method of a radionuclide nanomedicine for targeted treatment of breast cancer, including the following steps:

[0009] S1. Dissolve catalase in sugar-free DMEM, and add sodium phosphate [32P] solution, and stir and mix well;

[0010] S2. Add Ca 2+ to the mixture obtained in step S1, incubate at 37 °C, centrifuge, and collect the precipitate and redissolve it by ultrasonic treatment to obtain 32 <000032P>-labeled calcium phosphate nanoparticles;

[0011] S3. Disperse the 32 <000032P>-labeled calcium phosphate nanoparticles obtained in step S2 in ultrapure water, sequentially add Mn 2+ and DA-PEG-cRGD, continue to stir, centrifuge, and collect the precipitate and redissolve it to obtain the radionuclide nanomedicine.

[0012] Preferably, in step S1, the 32 <000032P> concentration is 1 mCi / mL, and the Ca 2+The concentration is 1 mol / L, and the Mn 2+ solution concentration is 10 mg / mL, and the DA-PEG-cRGD solution concentration is 40 mg / mL.

[0013] Preferably, in the step S2, Ca 2+ is CaCl 2 .

[0014] Preferably, the incubation time in the step S2 is 24 h, and the stirring time in the step S3 is 2 h.

[0015] Based on a general inventive concept, the present invention also provides an application of a radionuclide nanomedicine targeting breast cancer in the preparation of a medicament for treating breast cancer.

[0016] The principle of treating breast cancer in the present invention is as follows:

[0017] The radionuclide nanomedicine targeting breast cancer provided by the invention can target breast cancer cells through the modification of cRGD on the nanoparticle surface, and in-situ catalyze the degradation of excessive hydrogen peroxide in tumor cells to produce oxygen. At the same time, it rapidly degrades and releases radionuclides in the acidic microenvironment of the tumor 32 P. 32 P has a suitable half-life, and the β-rays emitted by it have high linear energy transfer, which is more likely to cause energy accumulation, and form non-toxic decay products after exerting therapeutic effects. 32 The β-rays emitted by P ionize to produce positrons in tumor cells, and can be converted into reactive oxygen species (ROS) under the supply of sufficient oxygen, thereby inducing nuclear DNA damage and initiating the apoptosis program. Through efficient 32 P targeted delivery and in-situ oxygen supply can effectively kill tumor cells and inhibit the growth and metastasis of primary breast cancer tumors.

[0018] The radionuclide nanomedicine can rapidly degrade and release drugs in response to the acidic microenvironment after targeting breast cancer, and can avoid the toxicity caused by the accumulation of carriers and radionuclides in the body. The radionuclide nanomedicine can relieve the hypoxia condition of breast cancer tumor tissues, and at the same time release the therapeutic radionuclide 32 P as an active ingredient to exert its medicinal effects. The nanoparticle can maintain good stability during blood circulation, with a low radionuclide leakage rate, and can rapidly degrade and release 32 P at the lesion site to exert its effects. Therefore, the radionuclide nanomedicine is an excellent systemic drug delivery system, which can avoid damage to normal tissues or organs, and the carrier components are all non-toxic substances, with good biocompatibility and biodegradability.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention utilizes catalase to regulate the biomineralization process of calcium phosphate. The formed calcium phosphate nanoparticles have a high radionuclide labeling rate and labeling stability, and have the characteristic of catalyzing the degradation of hydrogen peroxide to produce oxygen. Then, self-assembly is carried out using the coordination affinity between Mn 2+ and polyphenol derivatives to coat the calcium phosphate nanoparticles with a metal polyphenol nanonetwork. The preparation process is rapid and simple, the reaction process is controllable, green and environmentally friendly, without the need to add additional excipients and organic solvents, and no other impurities will be introduced. The radionuclide nanodrugs prepared by the biomineralization method and the self-assembly method have uniform particle sizes, exhibit a core-shell spherical structure, an average particle size of 80 nm, good dispersibility, and the spherical structure rapidly disintegrates under acidic conditions.

[0021] (2) The radionuclide nanodrug C-Ca 32 P@MPN provided by the present invention can rapidly degrade and release the drug in response to the acidic microenvironment after targeting breast cancer, avoiding the toxicity caused by the accumulation of the carrier and radionuclide in the body. Moreover, the nanoparticles can maintain good stability during blood circulation, with a low radionuclide leakage rate, and can rapidly degrade and release 32 P at the lesion site to exert its effect, avoiding damage to normal tissues or organs, and the carrier components are all non-toxic substances, having good biocompatibility and biodegradability.

[0022] (3) C-Ca 32 P@MPN has good stability in physiological media, slowly releases in PBS buffer at pH 7.4, but rapidly releases the 32 P in the nanoparticles in the weakly acidic environment of tumors at pH 5.5. In the presence of H 2 O 2 , a large amount of oxygen can be generated to relieve the hypoxic condition of breast cancer tumor tissues.

[0023] (4) C-Ca 32 P@MPN is beneficial to promoting the cellular uptake of 32 P. C-Ca 32 P@MPN accumulates more in tumors through active targeting, can significantly inhibit tumor growth, and significantly reduce the number of tumor metastasis nodules in the lungs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1C-Ca obtained from the detection of Experimental Example 1 of the present invention 32 Transmission electron microscope and particle size distribution diagram of P@MPN;

[0026] Figure 2 C-Ca obtained from the detection of Experimental Example 2 of the present invention 32 Element distribution diagram of P@MPN;

[0027] Figure 3 C-Ca obtained from the detection of Experimental Example 3 of the present invention 32 Transmission electron microscope image of the degradation of P@MPN in different pH environments;

[0028] Figure 4 C-Ca obtained from the detection of Experimental Example 4 of the present invention 32 P, C-Ca 32 Labeling stability diagram of P@MPN after incubation for different times and in different pH environments 32 P release curve; A is C-Ca 32 P, C-Ca 32 Labeling stability diagram of P@MPN after incubation for different times, B is the P release curve in different pH environments; 32 P release curve;

[0029] Figure 5 C-Ca obtained from the detection of Experimental Example 5 of the present invention 32 P, C-Ca 32 Dissolved oxygen generation curve of P@MPN incubated with hydrogen peroxide for different times;

[0030] Figure 6 Obtained from the detection of Experimental Example 6 of the present invention 32 P, C-Ca 32 Uptake map of P@MPN in breast cancer 4T1 cells;

[0031] Figure 7 Obtained from the detection of Experimental Example 7 of the present invention 32 P, C-Ca 32 P, C-Ca 32 In vitro anti-tumor result map of P@MPN;

[0032] Figure 8 C-Ca obtained from the detection of Experimental Example 8 of the present invention 32 In vivo pharmacokinetic curve and in vivo distribution map of P@MPN; A is C-Ca 32 In vivo pharmacokinetic curve of P@MPN; B is C-Ca 32 In vivo distribution map of P@MPN;

[0033] Figure 9 Obtained from the detection of Experimental Example 9 of the present invention 32 P, C-Ca32 P, C-Ca 32 In vivo antitumor results of P@MPN and H&E staining of the lungs; A is 32 P, C-Ca 32 P, C-Ca 32 In vivo antitumor results of P@MPN; B is C-Ca 32 H&E staining map of P@MPN in the lungs;

[0034] Figure 10 C-Ca obtained by detection in Experimental Example 10 of the present invention 32 H&E staining of mouse tissues after tail vein injection of P@MPN;

[0035] Figure 11 C-Ca obtained by detection in Experimental Example 11 of the present invention 32 Blood biochemical indexes of mice after tail vein injection of P@MPN. Embodiment

[0036] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0037] The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention. Without departing from the spirit and essence of the present invention, any modification or replacement made to the methods, steps or conditions of the present invention belongs to the scope of the present invention.

[0038] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art; unless otherwise specified, the reagents used in the embodiments are all commercially available.

[0039] Embodiment 1

[0040] Prepare the radionuclide nanodrug (C-Ca 32 P@MPN)

[0041] Prepare C-Ca 32 P nanoparticles by biomineralization method. Dissolve 100 mg of catalase in 10 mL of sugar-free DMEM, and add 100 μL of phosphorus 32 P] sodium salt solution (1 mCi / mL), stir and mix well, then add 100 μL of CaCl 2 (1 mol / L), incubate at 37 °C for 24 h. Centrifuge at 12000 rpm for 15 min, collect the precipitate and redissolve it by ultrasound to obtain C-Ca 32 P nanoparticles. Disperse the above nanoparticles in 10 mL of ultrapure water, and sequentially add 40 μL of MnCl 2(10 mg / mL), 40 μL DA-PEG-cRGD (40 mg / mL), continue stirring for 2 h, centrifuge, collect the precipitate and redissolve to obtain C-Ca 32 P@MPN nanoparticles.

[0042] For the nanomaterials obtained according to Example 1, detect the physicochemical properties, in vitro and in vivo pharmacokinetics and pharmacodynamics characteristics of C-Ca 32 P@MPN nanoparticles, specifically including microscopic morphology, particle size, elemental composition and distribution, cellular uptake, in vitro cytotoxicity, in vivo pharmacokinetics and distribution, and in vivo anti-tumor effect. Among them, the relevant nano-drugs obtained in Example 1 are elaborated specifically.

[0043] Experimental Example 1

[0044] Investigate the particle size of C-Ca 32 P@MPN

[0045] Take the sample solution and place it in a Marlven Nano ZS instrument. Use the dynamic light scattering method to detect the particle size. The temperature of the measurement cell is set at 25 °C, and each sample is operated in parallel for 3 replicates. Use TEM-EDS to observe the morphology of the nanoparticles: Drop the sample on a 400-mesh zinc grid covered with a carbon film, place it in a drying oven, and observe it under a transmission electron microscope Titan G2-F20 after it dries naturally.

[0046] The results are as Figure 1 shown, the particle size of C-Ca 32 P@MPN is about 80 nm, and it is a spherical core-shell nanostructure.

[0047] Experimental Example 2

[0048] Investigate the surface elemental distribution of C-Ca 32 P@MPN

[0049] Use TEM-EDS to observe the surface elemental distribution of the nanoparticles: Drop the sample on a 400-mesh zinc grid covered with a carbon film, place it in a drying oven, and observe it under a transmission electron microscope Titan G2-F20 after it dries naturally.

[0050] The results are as Figure 2 shown, six elements of C, O, N, P, Ca, and Mn are distributed on the surface of the nanoparticles.

[0051] Experimental Example 3

[0052] Investigate the acid-sensitive degradation performance of C-Ca 32 P@MPN

[0053] Use transmission electron microscopy imaging to investigate the acid-sensitive degradation performance of C-Ca 32 P@MPN: C-Ca 32P@MPN was incubated in PBS buffer at different pH values for a specific time, then dropped onto a 400-mesh zinc grid covered with a carbon film, placed in an oven, and after natural drying, observed under a transmission electron microscope Titan G2-F20.

[0054] The results are as Figure 3 shown. The nanoparticles could maintain a good core-shell nanostructure at pH 7.4, while the nanoparticles dissociated rapidly at pH 5.5, indicating that the acid-sensitive degradation property of C-Ca 32 P@MPN was beneficial for its rapid drug release in response to the acidic tumor microenvironment and exerted a killing effect.

[0055] Experimental Example 4

[0056] To investigate the 32 P radioactivity of C-Ca 32 P@MPN in solution

[0057] The radioactivity of 32 P in the solution was measured using a radioactivity meter to determine the radionuclide labeling stability and release behavior: The nanoparticles were separately dispersed in PBS buffer (10 mM) at pH 7.4 and 5.5. At 0, 1, 2, 4, 8, 12, 24, 36, and 48 h, the above solutions were taken, centrifuged at 12000 rpm for 15 min, and the supernatant was taken to measure the 32 radioactivity concentration of

[0058] P and calculate the cumulative release rate. Figure 4 The results are as 32 shown. C-Ca 32 P@MPN had good stability in physiological media, slowly released in PBS buffer at pH 7.4, and rapidly released

[0059] Experimental Example 5

[0060] To investigate the 32 oxygen production ability of C-Ca

[0061] The oxygen production ability of the nanoparticles was determined by monitoring the dissolved oxygen content in the solution: Different concentrations of C-Ca 32 P, C-Ca 32 P@MPN were mixed with H 2 O 2 (1 mM) in equal volumes, and the amount of dissolved oxygen produced within a certain time was monitored using a portable dissolved oxygen meter.

[0062] The results are as Figure 5 shown. C-Ca 32 P, C-Ca 32 P@MPN in the presence of H2 O 2 can produce a large amount of oxygen under the condition of

[0063] Experimental Example 6

[0064] Investigation of C-Ca 32 Cell uptake rate of P@MPN

[0065] Quantitative cell uptake using a gamma counter: Seed 4T1 cells at a density of 4×10 5 / well in a 6-well plate. After culturing overnight until the cells adhere to the wall, add 32 P, C-Ca 32 P@MPN and incubate for 1, 2, 4, 6 h. Digest, centrifuge, wash the cells twice with PBS and resuspend the cells. Detect the radioactivity using a gamma counter, and determine the cell uptake rate of the radionuclide drug at different incubation times according to the radioactivity of the cells.

[0066] The results are as Figure 6 shown. 4T1 cells have time-dependent uptake of 32 P, C-Ca 32 P@MPN, and the uptake amount of C-Ca 32 P@MPN is higher than that of 32 P, indicating that the nanocarrier is beneficial to promoting 32 cell uptake of P.

[0067] Experimental Example 7

[0068] Investigation of the inhibitory effect of C-Ca 32 P@MPN on tumor cells

[0069] MTT assay: Seed 4T1 cells at 5000 cells / well in a 96-well plate and culture overnight. Add complete medium containing gradient concentrations of each radionuclide nanopreparation, and the groups are 32 P, C-Ca 32 P, C-Ca 32 P@MPN. After incubating for 48 h, discard the liquid and wash the cells 3 times with PBS. Add MTT solution (1 mg / mL) and incubate for 4 h. Then aspirate the MTT solution and add 150 μL DMSO. Place it in a constant temperature shaker in the dark and shake for 10 min. Measure the absorbance of each well at 570 nm using a microplate reader and calculate the cell viability of each experimental group.

[0070] The results are as Figure 7 shown, 32 P, C-Ca 32 P, C-Ca 32 P@MPN all show concentration-dependent cytotoxicity. Since the endocytosis efficiency of C-Ca 32 P@MPN is higher than that of 32P and C-Ca 32 P, thus C-Ca 32 P@MPN exhibits the strongest tumor suppression effect.

[0071] Experimental Example 8

[0072] Investigate C-Ca 32 Accumulation of P@MPN at the tumor site

[0073] Construction of an orthotopic model of 4T1 breast cancer in BALB / c mice: 4T1 cells were cultured in complete 1640 medium. When the cells reached 90% confluence, they were digested with trypsin and centrifuged to suspend the cells in serum-free 1640 medium. The cell suspension (100 μL) was inoculated subcutaneously under the third left mammary pad of female mice at a concentration of 5×10 5 cells / mL to construct an orthotopic breast cancer model.

[0074] Measurement of radioactivity: When the tumor volume reached approximately 200 mm 3 3, radionuclide nanodrugs were injected via the tail vein. Blood samples (20 μL) were drawn from the orbital sinus at 1 h, 3 h, 6 h, 12 h, 24 h, and 48 h after administration, and the radioactivity in the blood samples was measured using a γ counter. In addition, 24 h after injecting the radionuclide nanodrugs, the mice were sacrificed, and the main organ tissues such as the heart, liver, spleen, lungs, kidneys, and tumors were collected, and the radioactivity was measured using a γ counter.

[0075] The results are as Figure 8 shown. Compared with free 32 P, C-Ca 32 P@MPN has a longer blood circulation time, which is beneficial for the accumulation of nanoparticles at the tumor site. Then, the in vivo distribution of the radionuclide was measured. C-Ca 32 P@MPN accumulates more in the tumor through active targeting and reaches the highest value at 12 h.

[0076] Experimental Example 9

[0077] Investigate C-Ca 32 Antitumor effect of P@MPN in vivo

[0078] When the tumor volume of the mice grew to 100 mm 3 , they were randomly divided into 5 groups: control group, 32 P, C-Ca 32 P, C-Ca 32P@MPN was administered via the tail vein. The major and minor diameters of the tumor were measured with vernier calipers within 14 days, and the tumor volume was calculated. A tumor volume-time change graph was plotted. In addition, after the mice were sacrificed, the lung tissues were dissected, washed clean with normal saline, fixed with 4% paraformaldehyde, embedded in paraffin, and sectioned. The sections were stained with hematoxylin and eosin (H&E), and histological analysis was performed by observing the sections under an optical microscope.

[0079] The results are as Figure 9 shown. Compared with the control group, 32 P and C-Ca 32 both showed a lower tumor suppression effect in the P group, indicating its lack of targeting, resulting in fewer nanoparticles reaching the tumor site, while C-Ca 32 the tumor was significantly suppressed after treatment in the P@MPN group, and the tumor metastasis nodules in the lungs were significantly reduced.

[0080] Experimental Example 10

[0081] Investigate the effect of C-Ca 32 P@MPN on internal organs in vivo

[0082] Healthy mice were injected with each radionuclide nanon preparation via the tail vein. After 24 h, the mice were sacrificed, and the heart, spleen, and kidney tissues were dissected, washed clean with normal saline, fixed with 4% paraformaldehyde, embedded in paraffin, and sectioned. The sections were stained with hematoxylin and eosin (H&E), and histological analysis was performed by observing the sections under an optical microscope.

[0083] The results are as Figure 10 shown. There were no obvious pathological changes in the main organs such as the heart, spleen, and kidney, indicating that C-Ca 32 P@MPN did not cause obvious damage to normal organs.

[0084] Experimental Example 11

[0085] Investigate the effect of C-Ca 32 P@MPN on the liver and kidney

[0086] Healthy mice were injected with each radionuclide nanon preparation via the tail vein. After 24 h, blood was collected from the orbital cavity, and the blood was placed in an EP tube and allowed to stand for 30 min to clot. The supernatant serum was obtained by centrifugation (4000 rpm, 5 min), and the biochemical indexes of ALT, AST, BUN, and CRE were detected using a biochemical detector.

[0087] The results are as Figure 11 shown. There were no obvious abnormalities in the biochemical indexes of ALT, AST, BUN, and CRE, indicating that 32 P, C-Ca 32 P, C-Ca 32 P@MPN caused no obvious liver and kidney damage.

[0088] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A radionuclide nanomedicine for targeted treatment of breast cancer, characterized in that Comprising a radionuclide 32 a calcium phosphate biomineralized nanocore labeled with 2+ P, and a metal polyphenol network nanoshell self-assembled from Mn 32 and a cRGD-modified polyphenol derivative; the nanocore is obtained by a biomineralization reaction of P-labeled phosphate groups and calcium ions under the regulation of catalase the cRGD-modified polyphenol derivative is dopamine-polyethylene glycol-cRGD polypeptide (DA-PEG-cRGD).

2. The radionuclide nanomedicine according to claim 1, characterized in that the particle size of the radionuclide nanomedicine is 50-100 nm.

3. A preparation method of a radionuclide nanomedicine according to any one of claims 1-2, characterized in that it comprises the following steps: S1. Dissolve catalase in sugar-free DMEM and add a 32 P] sodium phosphate solution, then stir and mix well; S2. Add Ca to the mixed solution obtained in step S1 2+ , incubate at 37 °C, centrifuge, and collect the precipitate, which is then redissolved by ultrasonic treatment to obtain 32 P-labeled calcium phosphate nanoparticles; S3. Disperse the calcium phosphate nanoparticles labeled with 32 P obtained in step S2 in ultrapure water, and sequentially add Mn 2+ , DA-PEG-cRGD, continue stirring, centrifuge, and collect the precipitate and redissolve it to obtain the radionuclide nanodrug.

4. The preparation method according to claim 3, characterized in that In the step S1 32 The concentration of P is 1 mCi / mL, and the concentration of Ca 2+ is 1 mol / L. The concentration of the Mn 2+ solution is 10 mg / mL, and the concentration of the DA-PEG-cRGD solution is 40 mg / mL.

5. The preparation method according to claim 3, characterized in that In the step S2, Ca 2+ is CaCl 2 , and in the step S3, Mn 2+ is MnCl 2 .

6. The preparation method according to claim 3, characterized in that in the step S2, the incubation time is 24 h, and in the step S3, the stirring time is 2 h.

7. Use of a radionuclide nanomedicine according to any one of claims 1-2 or a radionuclide nanomedicine prepared by the preparation method according to any one of claims 3-6 in the preparation of a medicament for treating breast cancer.

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