Preparation method and application of rutin coated manganese carbonate nanoparticle compound

Abstract

The invention discloses a preparation method and application of a rutin-coated manganese carbonate nanoparticle compound. The preparation method comprises the following steps: chelating Mn < 2 + > and polyphenol on rutin, and adding a sodium carbonate solution to obtain the rutin-coated manganese carbonate nanoparticle compound. The rutin-coated manganese carbonate nanoparticles are used as an MRI contrast agent, and are especially suitable for contrast of metastatic liver tumor focuses.

Description

Technical Field

[0001] The invention relates to the field of medical diagnostic materials, and in particular to a preparation method and application of a rutin-coated manganese carbonate nanoparticle composite. Background Art

[0002] Magnetic resonance (MRI) imaging is the most powerful imaging technology in biological tomography due to its high spatial resolution, superior penetration depth, and soft tissue resolution. However, due to the inherent low sensitivity of MRI, its application is limited in the early stages of the disease and in small lesions. In MRI, contrast agents can change the local regional magnetic field, shorten the relaxation time of surrounding tissues, and accelerate the relaxation process of surrounding protons, thereby improving the sensitivity and diagnostic accuracy of MRI.

[0003] Tumor metastasis is the main cause of cancer death. The liver is one of the most common organs of cancer metastasis due to its rich blood supply and nutrition. Early detection of liver metastases is crucial because appropriate treatment plans can be formulated according to the extent of liver metastasis within the treatment window. MRI technology has great potential in non-invasive monitoring of malignant tumor metastases. However, the subtle differences between normal liver tissue and small metastases make MRI diagnosis of small metastases very difficult, so it is necessary to introduce hepatobiliary specific contrast agents for auxiliary diagnosis. Primovist has a sensitivity of approximately (45-80%) for small metastases (1-2 cm), and even lower sensitivity for small metastases less than 1 cm (Hepato l.2016,65,5,1017-1030). Since Gd-based CAs are very likely to cause renal systemic nephropathy in patients with renal insufficiency, their clinical application is restricted by the Food and Drug Administration (Lancet Neuro l.2017,16,7,564-570.), therefore, there is an urgent need for alternatives to Gd-based CAs.

[0004] Amorphous iron nanoparticles and iron organic frameworks have been widely studied as therapeutic diagnostic agents due to their MRI contrast and ferroptosis-inducing ability (Nat Commun. 2018, 9, 1, 1410). However, these iron-based probes usually show "always on" and weak MR signals, so imaging will completely rely on the distribution of nanoparticles in the body, such as in lymph nodes containing a large number of macrophages and dendritic cells, which will lead to misdiagnosis of certain specific tissues. Manganese-based responsive CAs with significant relaxivity and ideal biocompatibility have recently received widespread attention. Manganese oxide (MnOx) nanomaterials are responsive to acidic environments and decompose into Mn under acidic conditions. 2+ , thereby shortening the T1 time of surrounding tissues and improving the T1 contrast effect. Although MnOx-based nanoparticles have been widely studied and achieved good results, most MnOx nanomaterials only release Mn at relatively low pH (4-6).2+ , and sometimes the reduction of the reducing molecule glutathione (GSH) is also required, resulting in signal activation limited to the cell, such as lysosomal pH (5-6), rather than the tumor microenvironment pH (6.4-6.8). And the cellular internalization dynamics of MnOx nanoparticles, including transmembrane pathways and intracellular distribution, become limiting factors that need to be addressed.

[0005] There are literature reports on manganese carbonate nanoparticles synthesized by microemulsion method, and polydopa-coated manganese carbonate nanoparticles synthesized by multi-step modification. After modification, the longitudinal relaxation rate r1 increased from 5.7mM-1s-1 to 6.3mM-1s-1, and the longitudinal relaxation rate was not shielded by the modification of polydopa, so it is not suitable as a pH-responsive contrast agent. In addition, the synthesis method is cumbersome. Although the polydopa coating is modified, a small amount of highly toxic surfactant CTAB may remain. According to reports, the cell survival rate of the nanoparticles has dropped to about 80% when the manganese concentration is only 600uM (ACS App l.Mater.2017,9,22,19296-19306).

[0006] In recent studies, there have been reports of using manganese carbonate contrast agents for magnetic resonance imaging of liver tumors, but such contrast agents have poor targeting, excessive injection doses, and potential risks to biosafety (ACS App l. Mater. 2021, 13, 18462-18471). In addition, there are also studies reporting that manganese tetraoxide nanoparticles synthesized by incomplete oxidation of manganese are used for integrated imaging, diagnosis and treatment of liver metastases, but the synthesis of this material is cumbersome, incomplete oxidation is uncontrollable, batch differences are difficult to control, and it is difficult to promote and apply (Nanoscale. 2023, 15, 4, 1583-1594). Summary of the invention

[0007] In order to solve the above-mentioned problems, the purpose of the present invention is to provide a method for preparing a rutin-coated manganese carbonate nanoparticle complex and its use as a MRI contrast agent. The rutin-coated manganese carbonate nanoparticle complex is used as an MRI contrast agent, which has good biosafety, can target glucose receptors and perform magnetic resonance imaging of specific areas (tumors or metastases) of a living body.

[0008] To achieve the purpose of the present invention, the following embodiments are provided.

[0009] In one embodiment, the present invention provides a use of a rutin-coated manganese carbonate nanoparticle complex for preparing an MRI contrast agent, wherein the nanoparticle complex targets a glucose receptor, and the manganese carbonate nanoparticle complex is prepared by the following method, which comprises treating a water-soluble manganese salt Mn 2+ It is obtained by chelating with polyphenols on rutin and then adding sodium carbonate solution to react.

[0010] Preferably, in the above-mentioned use of the present invention and the method, the solvent for the chelating reaction is dimethyl sulfoxide.

[0011] Preferably, in the above-mentioned use of the present invention, the rutin-coated manganese carbonate nanoparticle complex is used to prepare a liver metastasis tumor magnetic resonance imaging contrast agent.

[0012] In another embodiment, the present invention provides a method for preparing a rutin-coated manganese carbonate nanoparticle composite, comprising the following steps:

[0013] 1) Dissolve rutin in an organic solvent and add a water-soluble divalent manganese salt to react to make Mn 2+ Chelating with polyphenols on rutin;

[0014] 2) adding sodium carbonate solution to the reactant of step 1), stirring and reacting at room temperature;

[0015] 3) Separate the reaction product, and wash the separated solid with ethanol and water respectively to obtain.

[0016] Preferably, in the preparation method of the present invention, the organic solvent in step 1) is dimethyl sulfoxide.

[0017] Preferably, in the preparation method of the present invention, the water-soluble divalent manganese salt in step 1) is manganese chloride or manganese sulfate.

[0018] Preferably, in the preparation method of the present invention, the water-soluble divalent manganese salt is MnCl2·4H2O.

[0019] Preferably, in the preparation method of the present invention, the weight ratio of MnCl2·4H2O to rutin is (3-4):(3-10). Preferably, the weight ratio of MnCl2·4H2O to rutin is 3.3:(6-10), more preferably 3.3:10.

[0020] Preferably, in the preparation method of the present invention, the sodium carbonate solution in step 2) has a sodium carbonate concentration of 40 mM / ml.

[0021] Preferably, in the preparation method of the present invention, in step 2), sodium carbonate: Mn 2+ The molar ratio is 4:1.

[0022] Preferably, in the preparation method of the present invention, in step 3), the washing is performed once with ethanol and twice with water.

[0023] Preferably, the rutin-coated manganese carbonate nanoparticles prepared by the preparation method of the present invention have an irregular spherical or cubic morphology and a particle size of 140-200 nm, more preferably 140.8 nm.

[0024] In a specific embodiment, a method for preparing a rutin-coated manganese carbonate nanoparticle composite of the present invention comprises the following steps:

[0025] 1) Dissolve rutin in a 50 ml round-bottom flask containing dimethyl sulfoxide, add MnCl2·4H2O and react for 1 h.

[0026] 2) Add (5 ml, 200 mM) sodium carbonate solution to the reactants in step 1) under ultrasonic conditions and stir at room temperature.

[0027] 3) Collect by centrifugation, wash once with ethanol and twice with water without further purification.

[0028] In some preferred embodiments, in the method of the present invention, the concentration of rutin in the reaction system in step 1) is 3-10 mg / ml, more preferably 10 mg / ml. The dosage of dimethyl sulfoxide is 10 ml, and the concentration of MnCl2·4H2O is 3.3 mg / ml.

[0029] In some preferred embodiments, in the above method of the present invention, in step 2), the ultrasonic time is 3-5 min, more preferably 5 min.

[0030] In some preferred embodiments, in the above method of the present invention, in step 3), the centrifugal speed is controlled at 8000-10000 r / min.

[0031] In the above-mentioned uses and methods of the present invention, the rutin has a structure shown in Formula I:

[0032]

[0033] The rutin-coated manganese carbonate nanoparticle complex of the present invention targets glucose receptors, has the function of imaging a specific region (liver tumor) in a living body, and has the following advantages:

[0034] 1) The particles have uniform particle size, good water dispersibility, and a PD I of 0.105. They also have good stability and can be stored for a long time after freeze-drying.

[0035] 2) Rutin-coated manganese carbonate nanoparticles can be used for imaging specific areas of the organism, especially in the imaging of liver metastases of malignant tumors. The imaging of metastases smaller than 1 cm is significantly better than that of the clinical promixin contrast agent.

[0036] 3) The rutin-coated manganese carbonate nanoparticles of the present invention have two molecules of glycosides on the rutin that can target the glucose receptors overexpressed on the tumor, thereby reducing the dosage used in the imaging of liver metastasis of malignant tumors.

[0037] 4) After responding to the slightly acidic environment of the tumor (pH: 6.5-6.8), rutin-coated manganese carbonate nanoparticles have good longitudinal relaxation efficiency (r1=11.88mM-1s-1) at clinical 3.0T and low toxicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention shows the preparation process and structural schematic diagram of rutin-coated manganese carbonate nanoparticles.

[0039] Figure 2 Figure A shows the hydrodynamic diameter and PDI water dispersion coefficient of rutin-coated manganese carbonate nanoparticles in the ligand concentration range (0-10 mg / ml) and the corresponding transmission electron microscopy image, as well as the dynamic light scattering particle size distribution of the nanoparticles at the optimal ligand concentration of 10 mg / ml, the corresponding zeta potential and the dispersion coefficient PDI of the nanoparticles in water (Figure B).

[0040] Figure 3 A is the XRD pattern and B is the Fourier infrared pattern of rutin-coated manganese carbonate nanoparticles.

[0041] Figure 4 Effect of rutin-coated manganese carbonate nanoparticles on the Mn in tumor cells 4T1 and normal cells RAW 264.7 2+ The correlation bar graph between the concentration and cell viability.

[0042] Figure 5 Figure A is the relaxation efficiency fitting diagram of rutin-coated manganese carbonate nanoparticles before and after pH response at 3.0T and in the ligand concentration range (3.3-10 mg / ml), and the three-line table B of relaxation rate and particle size at different field strengths when the optimal ligand concentration is 10 mg / ml.

[0043] Figure 6 The targeting ability of rutin-coated manganese carbonate nanoparticles in tumor cells 4T1 and normal cells RAW, respectively. The incubation time between the control groups was the same. (a, b) and (d, e) represent the relaxation efficiency of the materials in 4T1 cells and RAW cells, respectively (n = 3). (c) and (f) represent the relaxation efficiency of the materials in 1×10 6 Mn in 4T1 cells and RAW cells 2+ The content.

[0044] Figure 7 This is the imaging effect of the targeting ability of rutin-coated manganese carbonate nanoparticles on 4T1 subcutaneous tumors in vivo.

[0045] Figure 8The contrast images of liver metastases specifically enhanced by rutin-coated manganese carbonate nanoparticles, where (a) is a liver metastasis identification image (yellow circle), (bc) are macroscopic and microscopic (H&E) staining images of the liver to confirm the location of metastatic tumors, (d) is a contrast intensity image, and (ef) is a transverse relaxivity image. DETAILED DESCRIPTION

[0046] The following examples are for describing the present invention in more detail. However, the following examples are provided only to help further understand the present invention and are not intended to limit the present invention. Those skilled in the art should understand that the equivalent replacements made to the content of the present invention, or corresponding improvements, still belong to the protection scope of the present invention.

[0047] The following examples are merely representative and are used to further understand the spirit of the present invention, but are not intended to limit the scope of the present invention.

[0048] The structural schematic diagram and preparation process of the rutin-coated manganese carbonate nanoparticles of the present invention are shown in Figure 1 .

[0049] The particle size of rutin-coated manganese carbonate nanoparticles is adjusted by adjusting the concentration of rutin ligand in the reaction system. As the amount of ligand increases, the synthesized particle size becomes smaller and the dispersibility becomes better.

[0050] Example 1 Preparation of rutin-coated manganese carbonate nanoparticles composite

[0051] The preparation method specifically comprises the following steps:

[0052] Different concentrations of ligand (0-10mg / ml) i.e. 0mg, 5mg, 10mg, 50mg, 100mg and 150mg of rutin (Rutin) were dissolved in a 50ml round-bottom flask containing 10ml of DMSO, and 50mg of MnCl2·4H2O was added and stirred for 1h. Under ultrasonic conditions, (5ml, 200mM) sodium carbonate solution was added, and after ultrasonication for 5min, the color changed from light yellow to dark green, and then stirred at room temperature for 4h. The product was collected and centrifuged at 8000r / min for 5min and collected, washed once with ethanol and twice with water, and no further purification was required. The obtained product was rutin-coated manganese carbonate nanoparticles (Rutin@MnCO3), which were dissolved in 5ml ultrapure water and stored at 4°C.

[0053] Example 2 Preparation of Rutin-coated Manganese Carbonate Nanoparticles Composite

[0054] The preparation method specifically comprises the following steps:

[0055] Dissolve 100 mg of rutin in a 50 ml round-bottom flask containing 10 ml of dimethyl sulfoxide, add 50 mg of MnCl2·4H2O and stir for 1 hour. Add (5 ml, 200 mM, 21.2 g) sodium carbonate solution under ultrasonic conditions, and stir at room temperature for 4 hours after the color changes from light yellow to dark green after ultrasonic treatment for 5 minutes. Collect the product and centrifuge it at 8000 r / min for 5 minutes and collect it, wash it once with ethanol and twice with water, and no further purification is required. The obtained product is rutin-coated manganese carbonate nanoparticles, which are dissolved in 5 ml of ultrapure water and stored at 4°C.

[0056] Example 3 Preparation of rutin-coated manganese carbonate nanoparticles composite

[0057] The preparation method specifically comprises the following steps:

[0058] Dissolve 150 mg of rutin in a 50 ml round-bottom flask containing 10 ml of dimethyl sulfoxide, add 50 mg of MnCl2·4H2O and stir for 1 hour. Add (5 ml, 200 mM) sodium carbonate solution under ultrasonic conditions, and stir at room temperature for 4 hours after the color changes from light yellow to dark green after ultrasonication for 5 minutes. Collect the product and centrifuge it at 8000 r / min for 5 minutes and collect it, wash it once with ethanol and twice with water, and no further purification is required. The obtained product is rutin-coated manganese carbonate nanoparticles, and the product is dissolved in 5 ml of ultrapure water and stored at 4°C.

[0059] Example 4 Structural Characterization, Properties and In Vivo Application of Rutin-coated Manganese Carbonate Nanoparticles Prepared

[0060] 1. Particle size and distribution test

[0061] The rutin-coated manganese carbonate nanoparticles prepared in Example 1 were used to measure the particle size and particle size distribution of the nanoparticles using dynamic light scattering. The results are as follows: Figure 2 As shown in (a), the dynamic light scattering particle size distribution results of the nanoparticles show that the size of the nanoparticles can be well controlled by adjusting the concentration of the rutin ligand in the reaction system. As the concentration of the rutin ligand increases, the rutin-coated manganese carbonate nanoparticles become smaller. For example, when the concentration of the rutin ligand is 3.3 mg / mL, 6.7 mg / mL, and 10.0 mg / mL, the average particle sizes of the prepared rutin-coated manganese carbonate nanoparticles are 196.2 nm, 194 nm, and 140.8 nm, respectively, and the dispersibility gradually improves. The test results prove that the size of the nanoparticles can be well controlled by adjusting the concentration of rutin in the reaction system.

[0062] The optimal rutin ligand-coated manganese carbonate nanoparticles obtained in Example 2 were subjected to dynamic light scattering, ζ test and PD I dispersibility test. The results are as follows: Figure 2(b) The optimal rutin-coated manganese carbonate nanoparticles have a good PD I water dispersibility index of 0.105 and a zeta potential of -21.6 mv, which is beneficial to the circulation of nanoparticles in the blood.

[0063] 2. Crystal form testing and Fourier infrared characterization

[0064] The rutin-coated manganese carbonate nanoparticles prepared in Example 3 were subjected to X-ray diffraction detection. The peak positions in the spectrum were consistent with those of known MnCO3 crystals, proving that the prepared nanoparticles were manganese carbonate. The results are shown in Figure 3 (a). The rutin-coated manganese carbonate nanoparticles prepared in Example 3 were characterized by Fourier transform infrared spectroscopy. The spectrum confirmed that the rutin-coated manganese carbonate nanoparticles had characteristic functional groups C=O stretching vibration, COC stretching vibration and CO32- stretching vibration, further proving the successful synthesis of the material. The results are shown in Figure 3 (b).

[0065] 3. In vitro cell biosafety test

[0066] RAW264.7 cells and 4T1 cells were placed in DMEM complete medium (10% fetal bovine serum, 100 U / mL penicillin and 100 μg / mL streptomycin) and RPMI 1640 complete medium (10% fetal bovine serum, 100 U / mL penicillin and 100 μg / mL streptomycin), respectively, and routine subculture was performed in a cell culture incubator with a CO2 content of 5%, a relative humidity of 90% and a temperature of 37°C. When the cells were in the logarithmic growth phase, the old culture medium was discarded, trypsin was added to digest for 5 min, and the cells were collected by centrifugation. 4T1 and RAW264.7 cells were plated at 1×10 4 Each group of 5 cells was plated on a 96-well plate. Five blank wells and control wells were set up respectively, and each blank well contained only 100u l complete medium. The control wells contained only cells and 100u l complete medium. Rutin-wrapped manganese carbonate nanoparticles were used as the unit of manganese ion concentration, and 100u l of nanoparticles containing 5, 10, 30, 50, and 80ug / ml manganese ions were added to each group using complete medium as solvent and incubated with cells for 24h. After that, 10u l of CCK-8 solution was added to each well and incubated for 30min-1h. The OD value was measured at 450nm on an enzyme reader. The formula for cell survival rate is: (OD value of experimental well-OD value of blank well) / (OD value of control well-OD value of blank well). See the results. Figure 4 The results showed that when the manganese concentration was 80ug / ml, i.e. 1455uM, the survival rate in tumor cells 4T1 and normal cells RAW264.7 was higher than 80%, indicating good biosafety.

[0067] 4. Contrast effect characteristic test

[0068] Atomic absorption was used to determine the manganese concentration in the nanoparticle solution. According to the manganese concentration, the rutin-coated manganese carbonate nanoparticles prepared in Example 1 were prepared into solution samples with different concentrations of manganese content of 0.1, 0.2, 0.3, 0.4, and 0.5 mM, respectively, with concentrations of 3.3 mg / ml, 6.7 mg / ml, and 10 mg / ml, i.e., ligand amounts (50 mg, 100 mg, and 150 mg). A 3.0 T magnetic resonance relaxation efficiency instrument was used to measure the T1 relaxation time of each sample in a neutral environment before response and in a slightly acidic environment after response, pH: 6.6, and calculate the T1 relaxation efficiency (r1). The results are shown in Table 1. Figure 5 The results show that the r1 before response of the nanoparticles synthesized with different ligand concentrations is 0.64, 0.96, 1.00mM-1s-1, and after response is 9.83, 10.02, 11.88mM-1s-1, respectively. Figure 5 (a). The r1, r2 and r2 / r1 values ​​of nanoparticles with different ligand amounts at different clinical field strengths of 0.5T, 1.5T and 3.0T after responding to a slightly acidic environment at pH 6.6, as shown in Figure 5 (b) The results show that when the optimal ligand concentration is 10 mg / ml, the obtained nanoparticles have the smallest particle size, the best dispersibility, the higher post-response relaxation efficiency and the smaller r2 / r1 ratio.

[0069] 5. In vitro targeting glucose receptor ability test

[0070] RAW264.7 cells and 4T1 cells were placed in DMEM complete medium (10% fetal bovine serum, 100 U / mL penicillin and 100 μg / mL streptomycin) and RPMI 1640 complete medium (10% fetal bovine serum, 100 U / mL penicillin and 100 μg / mL streptomycin), respectively, and routine subculture was performed in a cell culture incubator with a CO2 content of 5%, a relative humidity of 90% and a temperature of 37°C. When the cells were in the logarithmic growth phase, the old culture medium was discarded, and trypsin was added to digest the cells for 5 min and centrifuged to collect them. 4T1 and RAW264.7 were evenly spread on six-well plates, and the cells were counted and controlled to be 1×10 per well. 6 RAW264.7 and 4T1 cells were divided into two groups (n=3). Glucose was added to inhibit the overexpressed glucose receptors on the tumor. One group of normal cells and the other group of tumor cells were added with PBS solution containing 20% ​​glucose, and the other group was added with normal PBS solution. The concentration of nanoparticles was controlled to be consistent between the groups, and the incubation time was 2h. The amount of nanoparticles taken up by tumor cells was determined by measuring the T1 relaxation efficiency and metal ion concentration of the two different treatment groups. Atomic absorption was used to determine the manganese concentration in the nanoparticle solution. The results are shown in Figure 6The results showed that the rutin-coated manganese carbonate nanoparticles prepared in Example 3 had a T1 relaxation effect in 4T1 cells at manganese concentrations of 30 mM, 50 mM and 80 mM. Figure 6 (a, b) and the metal ion content in the cell, e.g. Figure 6 (c) was statistically significant between the two groups, but in normal RAW264.7 cells, with the increase of manganese concentration, both T1 relaxation efficiency (see Figure 6 (d, e)) or metal ion content (see Figure 6 (f)) were not statistically significant. The results showed that rutin-coated manganese carbonate nanoparticles have the ability to target overexpressed glucose in tumor cells 4T1.

[0071] 6. In vivo targeting of subcutaneous 4T tumors

[0072] 5 × 10 6 4T1 cells were used to construct a subcutaneous tumor model. When the tumor grew to 20 mm 3 The mice were divided into two groups (n=3), one group was injected with 25% glucose (Glu) 30 minutes in advance, and the other group was injected with saline 30 minutes in advance. Atomic absorption was used to determine the manganese concentration in the nanoparticle solution. The rutin-coated manganese carbonate nanoparticles prepared in Example 3 were injected with a manganese concentration of 0.1 mmol / kg in each group. The difference between the different treatment groups was compared by measuring the signal ratio of the tumor at the same level after injection to that before injection, i.e., SI post / SI pre. The results showed that the glucose-treated group (Glu) and the saline-treated group were statistically significant at 60 minutes and 120 minutes, indicating that the rutin-coated manganese carbonate nanoparticles also have the ability to target tumor glucose receptors in vivo. At the same time, the contrast effect of the clinical contrast agent Gd-DTPA on subcutaneous 4T1 tumors at the same Gd injection dose of 0.1 mmol / kg was also compared. In addition, the targeting ability in vivo was determined by comparing the signal value ratio before and after injection at the same level of the tumor in the glucose (Glu) inhibition group or the normal group at different time points. The contrast effect of the clinical contrast agent Gd-DTPA on subcutaneous 4T1 tumors at the same injection dose was also compared. The results are shown in Figure 2. Figure 7 shown.

[0073] 7. Application of Rutin-coated Manganese Carbonate Nanoparticles in Magnetic Resonance Imaging of Liver Metastases

[0074] By injecting 1×10 64T1 cells were used to construct liver metastases, which were ready for injection 5-6 days later. Atomic absorption was used to determine the manganese concentration in the nanoparticle solution. Rutin-coated manganese carbonate nanoparticles prepared in Example 3 were intravenously injected with rutin-coated manganese carbonate nanoparticles with a manganese concentration of 0.1 mmol / kg and a clinical hepatobiliary specific contrast agent, Promec, with a gadolinium concentration of 0.1 mmol / kg. T1-weighted MR images were collected at representative time points using a 3.0T scanner. The results are shown in Figure 8 As shown, metastases (yellow circles) are easily identifiable. Figure 8 (a). Macroscopic and microscopic (H&E) stained images of the liver confirm the location of metastatic tumors, such as Figure 8 (bc). The contrast intensity ratio, i.e., the signal value of the metastasis to the signal value of the liver, shows that rutin-coated manganese carbonate nanoparticles have an ultra-high contrast of 219% in 4T1 liver metastases on magnetic resonance imaging, while promilast has a negative contrast. Figure 8 (d) Comparison of the signal-to-noise ratio of liver metastases and normal liver tissue after injection of rutin-coated manganese carbonate nanoparticles. The results showed that, unlike Promec, rutin-coated manganese carbonate nanoparticles increased the longitudinal relaxivity of liver metastases and shortened the transverse relaxivity in normal liver tissue. Figure 8 (ef).

[0075] The results showed that rutin-coated manganese carbonate nanoparticles were significantly better than clinical promeconium contrast agent in imaging 4T1 malignant tumor liver metastasis with a diameter of <1 mm. Data are presented as SD±mean (n=3 / group). Figure 8 The results show that liver metastases (yellow circles) are easily identified (a). Macroscopic and microscopic (H&E) staining images of the liver can confirm the location of metastatic tumors (bc). The contrast intensity ratio shows that rutin-coated manganese carbonate nanoparticles have a higher contrast of 219% in metastases, while promecon has a negative contrast (d). After using the rutin-coated manganese carbonate nanoparticle probe of the present invention, the signal-to-noise ratio of metastatic tumors and liver tissues was analyzed. The results show that, unlike promecon, rutin-coated manganese carbonate nanoparticles lead to an increase in the longitudinal relaxation efficiency of metastases, while having a shortening effect on the transverse relaxation efficiency in normal liver tissue (ef).

Claims

1. A use of a rutin-coated manganese carbonate nanoparticle complex for the manufacture of an MRI contrast agent, wherein the nanoparticle complex targets a glucose receptor, and the manganese carbonate nanoparticle complex is prepared by the following method, comprising: 2+ It is obtained by chelating with polyphenols on rutin and then adding sodium carbonate solution to react.

2. The use according to claim 1, wherein the solvent for the chelation reaction is dimethyl sulfoxide.

3. The use according to claim 1, wherein the rutin-coated manganese carbonate nanoparticle complex is used to prepare a liver metastasis tumor magnetic resonance imaging contrast agent.

4. A method for preparing a rutin-coated manganese carbonate nanoparticle composite, comprising the following steps: 1) Dissolve rutin in an organic solvent, dimethyl sulfoxide, and add a water-soluble divalent manganese salt to react to make Mn 2+ Chelating with polyphenols on rutin; 2) adding sodium carbonate solution to the reactant of step 1), stirring and reacting at room temperature; 3) Separate the reaction product, and wash the separated solid with ethanol and water respectively to obtain.

5. The preparation method according to claim 4, wherein the water-soluble divalent manganese salt in step 1) is manganese chloride or manganese sulfate.

6. The preparation method according to claim 5, wherein the water-soluble divalent manganese salt is MnCl2·4H2O.

7. The preparation method according to claim 6, wherein the weight ratio of MnCl2·4H2O to rutin is (3-4):(3-10), preferably 3.3:(6-10), and more preferably 3.3:

10.

8. The preparation method according to claim 4, wherein the average particle size of the prepared rutin-coated manganese carbonate nanoparticles is 140-200 nm.

9. The preparation method according to claim 8, wherein the weight ratio of MnCl2·4H2O to rutin is 3.3:

10.

10. The preparation method according to claim 4, wherein the sodium carbonate solution in step 2) has a sodium carbonate concentration of 40 mM / ml, preferably, sodium carbonate: Mn 2+ The molar ratio is 4:1.

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