Amino ferrocene modified black phosphorus compound containing stable free radicals as well as preparation method and application of amino ferrocene modified black phosphorus compound

Abstract

The invention relates to an amino ferrocene modified black phosphorus compound containing stable free radicals and a preparation method and application thereof.The amino ferrocene modified black phosphorus compound containing the stable free radicals is obtained by covalently modifying the surface of black phosphorus with amino ferrocene, and the amino ferrocene and the black phosphorus are combined through a P-C-N bond; the compound contains stable free radicals and has room-temperature ferromagnetism. The amino ferrocene modified black phosphorus compound containing the stable free radicals contains the stable free radicals, has room-temperature ferromagnetism, low toxicity and high biological safety, has no renal toxicity and brain deposition risk compared with a traditional gadolinium-based contrast agent, has saturation magnetization (Ms) three times of that of SPIONs under the condition of the same mass Fe content, and has a good application prospect. When in use, the required iron concentration is extremely low, so that cell injury and organ failure can be avoided to a great extent, and the compound can be used for an MRI contrast agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear magnetic resonance contrast agents, and in particular relates to an aminoferrocene-modified black phosphorus complex containing stable free radicals, and a preparation method and application thereof. Background Art

[0002] Magnetic resonance imaging (MRI) contrast agents are an important aid in disease diagnosis, and their performance optimization has been a research hotspot in the field of medical imaging. Currently, contrast agents are primarily classified into two categories: metal-based (e.g., gadolinium-based, iron-based) and non-metal-based (e.g., nitroxide-based). However, both types have significant drawbacks in clinical application.

[0003] Metal-based contrast agents, such as paramagnetic gadolinium (Gd)-based nanoparticles and superparamagnetic iron oxide nanoparticles (SPIONs), were the most common MRI contrast agents in the past. Although gadolinium-based contrast agents (GBCAs) occupy a major share of the magnetic resonance imaging market, their clinical application is restricted by two fatal flaws: on the one hand, they may cause renal damage, resulting in strict restrictions on the use of this preparation in patients with impaired renal function; on the other hand, gadolinium ions show abnormal deposition in central nervous tissues such as the brain. In contrast, superparamagnetic iron oxide nanoparticles (SPIONs) exhibit better biosafety, but their limitations are equally significant: limited targeting limits diagnostic accuracy, and excessive iron ions not only interfere with iron metabolism in the body, but also produce reactive oxygen species (ROS) through the Fenton reaction, leading to cell damage and organ failure.

[0004] Therefore, it is crucial to regulate the concentration of iron in the body when using it.

[0005] Non-metallic contrast agents, such as nitroxides, avoid the toxicity of heavy metals but face two major technical bottlenecks: First, the active sites in their molecular structures are easily affected by the body's redox environment, resulting in insufficient chemical stability and prone to degradation or metabolic inactivation, especially under physiological conditions. Second, their paramagnetic centers do not achieve optimal electron spin states, resulting in low longitudinal relaxation rates and significantly weaker imaging performance than mainstream clinical contrast agents. Furthermore, due to the short half-life of nitroxide MRI contrast agents, physicians must perform MRI examinations as soon as possible after injection to capture the optimal imaging effect of the contrast agent in the body, which increases the urgency of examination and diagnosis.

[0006] In summary, existing contrast agents are difficult to meet the current requirements in this field for low toxicity, low heavy metal content, long-term stability and targeted functionalization. Therefore, there is an urgent need to develop new contrast agents. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art and provide an aminoferrocene-modified black phosphorus complex containing stable free radicals, as well as a preparation method and application thereof. The aminoferrocene-modified black phosphorus complex containing stable free radicals has low toxicity, low metal content, good stability, and strong targeting. As a contrast agent, it can perform long-term sensitive detection of lesion locations.

[0008] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0009] An aminoferrocene-modified black phosphorus complex containing stable free radicals is obtained by covalently modifying aminoferrocene (AFc) on the surface of black phosphorus (BP), wherein the aminoferrocene and black phosphorus are bonded via a PCN bond. The complex contains stable free radicals and has room-temperature ferromagnetism. The molecular structure is shown in the following formula (I):

[0010]

[0011] According to the above scheme, the aminoferrocene-modified black phosphorus complex containing stable free radicals has a layered structure of multi-layer nanosheet stacking, with 25 to 45 stacked layers, a size of 2 to 5 μm, a thickness of 15 to 25 nm, and P, C, N, and Fe elements evenly distributed on the surface.

[0012] The present invention also provides a method for preparing the aminoferrocene-modified black phosphorus complex containing stable free radicals, the specific steps of which are as follows:

[0013] 1) Weighing blocky black phosphorus, adding the blocky black phosphorus to N,N-dimethylformamide (DMF) to obtain a black phosphorus mixture, and sequentially subjecting the obtained black phosphorus mixture to ultrasonication and ultrasonic water bath treatment to obtain a dark brown black phosphorus suspension;

[0014] 2) Under inert atmosphere, the black phosphorus suspension obtained in step 1) is uniformly mixed with dichloromethane, and then aminoferrocene or a dichloromethane dispersion of aminoferrocene is added, oxygen and moisture in the system are removed, and the mixture is heated under reflux to react. After the reaction is completed, the solid phase product is separated, washed, and dried to obtain the product.

[0015] According to the above scheme, the concentration of the black phosphorus mixed solution in step 1) is 0.5-2 mg / mL.

[0016] According to the above scheme, the ultrasonic crushing treatment time in step 1) is 3 to 6 hours, and the water bath ultrasonic treatment time is 3 to 6 hours.

[0017] According to the above scheme, in step 2), the black phosphorus suspension and dichloromethane are uniformly mixed, and the volume ratio of the black phosphorus suspension to dichloromethane is 0.5-1.5:1.

[0018] According to the above scheme, in step 2), the mass of aminoferrocene or the mass of aminoferrocene in the dichloromethane dispersion of aminoferrocene is 20-40% of the mass of black phosphorus in the black phosphorus suspension. The dichloromethane dispersion of aminoferrocene is obtained by dispersing aminoferrocene in dichloromethane, and the concentration is 4-12 mg / mL.

[0019] According to the above scheme, the heating reflux reaction conditions in step 2) are: reaction at 95-105°C for 8-12 hours.

[0020] According to the above scheme, the separation method in step 2) is: centrifugation at 8000-12000 rpm for 5-10 minutes, then removing the supernatant and collecting the precipitate.

[0021] According to the above scheme, the washing method in step 2) is: adding ethanol, then centrifuging at 8000-10000 rpm for 5-10 minutes, washing 2-3 times, and collecting the precipitate.

[0022] According to the above scheme, the drying method in step 2) is: placing in a vacuum drying oven at 30-50° C. and drying for 3-24 hours.

[0023] The present invention also includes the use of the aminoferrocene-modified black phosphorus complex containing stable free radicals in contrast agents.

[0024] The present invention also includes a probe based on the aminoferrocene-modified black phosphorus complex containing stable free radicals, which is obtained by modifying the aminoferrocene-modified black phosphorus complex containing stable free radicals with a targeting molecule.

[0025] According to the above scheme, the targeting molecules include one or more of hyaluronic acid (HA), macrophage vesicle membrane, liposome, and statins.

[0026] According to the above scheme, the molecular modification method is physical modification or chemical modification.

[0027] The present invention also includes the use of the probe based on the aminoferrocene-modified black phosphorus complex containing stable free radicals in contrast agents and diagnostic and therapeutic agents.

[0028] The present invention uses black phosphorus as a matrix. By covalently modifying the black phosphorus surface with aminoferrocene, a ferrocene ring connected to Fe in AFc dissociates during the preparation process to form a conjugated structure. The Fe in FcP· is a more stable trivalent iron ion, thereby generating a stable ferrophosphine free radical (FcP·). The product is not prone to agglomeration and has increased stability. Only a small amount of iron is required to exhibit strong room-temperature ferromagnetism in a magnetic field environment, and the harm to the body is also reduced. This fills the technical gap in the existing field and provides an innovative solution to address the limitations of existing contrast agents.

[0029] The beneficial effects of the present invention are: 1. The aminoferrocene-modified black phosphorus complex containing stable free radicals provided by the present invention contains stable free radicals and has room temperature ferromagnetism, has lower toxicity and higher biosafety, has no risk of nephrotoxicity and brain deposition compared to traditional gadolinium-based contrast agents, and compared to traditional iron-based contrast agents, under the same mass of Fe content, its saturation magnetization (Ms) is three times that of SPIONs, and the required iron concentration during use is extremely low, which can greatly avoid cell damage and organ failure, and can be used as an MRI contrast agent. Compared with traditional non-metallic free radical contrast agents, the contrast agent shows significant advantages, good stability, prolonged blood circulation half-life, long imaging time, strong targeting, and can perform long-term sensitive detection of lesion locations. 2. The aminoferrocene-modified black phosphorus complex containing stable free radicals of the present invention can be modified by molecular design through targeting molecules and drugs to obtain functional probes, which can be used as diagnostic and therapeutic agents. 3. The preparation method of the present invention has the advantages of simple process, simple synthesis steps, warm reaction conditions, good repeatability, and is convenient for industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a scanning electron microscope image of the product prepared in Example 1 of the present invention;

[0031] Figure 2 This is an atomic force microscope image of the product prepared in Example 1;

[0032] Figure 3 This is a comparison of the particle size changes of the BP dispersion and the FcP dispersion in Example 1 after 14 days of storage;

[0033] Figure 4 Energy dispersive X-ray spectrogram of the product prepared in Example 1;

[0034] Figure 5 The X-ray diffraction (XRD) and transmission electron microscopy (TEM) test patterns of the raw materials black phosphorus (BP), aminoferrocene (AFc), and the resulting product (FcP·) used in Example 1 are shown;

[0035] Figure 6 This is the X-ray photoelectron spectrum test diagram of the product prepared in Example 1;

[0036] Figure 7 The UV-Vis spectra, FT-IR spectra, and Raman spectra of the raw materials black phosphorus and aminoferrocene used in the examples and the resulting products are shown in Figure 1.

[0037] Figure 8 This is a comparison chart of the element mass percentages of C and N modified on the surface of the product obtained in Example 1;

[0038] Figure 9 The EPR spectra of the raw materials black phosphorus (BP), aminoferrocene (AFc) and the resulting product (FcP·) used in Example 1 are shown;

[0039] Figure 10 Magnetic properties test diagram of black phosphorus (BP), aminoferrocene (AFc) and the resulting product (FcP·) used in Example 1;

[0040] Figure 11 This is a comparison chart of cell viability of the product prepared in Example 1 at different concentrations;

[0041] Figure 12 TEM image of hyaluronic acid-modified FcP· prepared in Example 2;

[0042] Figure 13 This is the FT-IR spectrum of the hyaluronic acid-modified FcP· prepared in Example 2;

[0043] Figure 14 This is a test graph of the relaxivity of HA-FcP prepared in Example 2;

[0044] Figure 15 TEM image of the macrophage membrane-encapsulated drug-modified FcP· prepared in Example 3;

[0045] Figure 16 This is the FT-IR spectrum of the macrophage membrane-encapsulated drug-modified FcP· prepared in Example 3. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings.

[0047] Example 1

[0048] An aminoferrocene-modified black phosphorus complex (FcP·) containing stable free radicals, and its preparation

[0049] Here’s how:

[0050] 1) Weigh 40 mg of blocky black phosphorus and add it to 40 mL of N,N-dimethylformamide to obtain a black phosphorus mixture. The resulting black phosphorus mixture is first ultrasonically disrupted in an ultrasonic cell disruptor for 4 hours, and then ultrasonically sonicated in an ultrasonic water bath for 4 hours to obtain a brown black phosphorus suspension.

[0051] 2) Under nitrogen protection, the black phosphorus suspension obtained in step 1) and 40 mL of dichloromethane were poured into a three-necked round-bottom flask and stirred to mix evenly (note that one of the outlets of the three-necked flask was connected with a balloon), and then a dichloromethane dispersion of aminoferrocene (12 mg of aminoferrocene was ultrasonically dispersed in 2 mL of dichloromethane) was quickly added with a syringe. Nitrogen was introduced into the flask and vacuumed three times to remove oxygen and water molecules from the system. The mixture was then heated to 100°C and stirred at this temperature for 10 hours. After the reaction, the three-necked flask was removed and ultrasonically treated in a water bath for 5 minutes. The reaction solution was then divided into centrifuge tubes and centrifuged at 10,000 rpm for 5 minutes. The supernatant was poured out and the resulting precipitate was washed twice with ethanol, centrifuged at 10,000 rpm for 5 minutes each time. The precipitate was collected and dried in a vacuum drying oven at 40°C for 12 hours to obtain the product.

[0052] The scanning electron microscope (SEM) of the product prepared in this example is as follows Figure 1 As shown, it can be seen that the product presents a flake structure with a size of 2 to 5 μm.

[0053] The atomic force microscope (AFM) image of the product prepared in this example is as follows Figure 2 As shown in a, the three-dimensional high-resolution profile of the product can be observed, which is a layered structure of multi-layer nanosheets stacked, as shown in Figure 2 b is the product thickness map obtained by atomic force microscopy. After measurement, it was found that its thickness is 18nm, and the corresponding number of stacking layers is about 33 layers.

[0054] The raw material black phosphorus (BP) and the prepared product (FcP·) used in this example were ultrasonically dispersed in deionized water to prepare BP dispersion and FcP· dispersion with a concentration of 50 μg / mL. The particle size changes of the two dispersions were measured by dynamic light scattering (DLS) after being placed at room temperature for 0, 1, 3, 7, and 14 days. The test results are shown in Figure 2. Figure 3 As shown, it can be seen that FcP· exhibits enhanced environmental stability relative to BP.

[0055] The surface element analysis of the product prepared in this example was performed using an energy dispersive X-ray spectrometer (EDS) accessory equipped with a scanning electron microscope (SEM). The results are as follows: Figure 4 As shown, it can be seen that the surface of the product is composed of P, C, Fe, and N elements, and the elements are evenly distributed.

[0056] The raw materials black phosphorus (BP), aminoferrocene (AFc) and the obtained product (FcP·) used in this example were tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Figure 5Figure a shows the XRD test pattern. It can be seen that AFc is in an amorphous state. The XRD pattern of FcP· has sharp and high characteristic diffraction peaks. The diffraction peaks of FcP· can overlap with the standard XRD diffraction peaks of BP (JCPDS No.73-1358), showing the characteristic peaks of the orthorhombic phase, proving that FcP· and BP have extremely similar crystal structures. Figure 5 b shows the TEM image of FcP·. It can be seen that the lattice spacing of FcP· is and They correspond to the (020) and (021) crystal planes of BP, respectively, and the amorphous regions appearing at the edges are the aggregations of AFc.

[0057] The elemental composition and valence state of the product prepared in this embodiment were tested by X-ray photoelectron spectroscopy (XPS). Figure 6 shown. Figure 6 a is the high-resolution XPS spectrum of P element, showing the P 2s and P 2p peaks of phosphorus at 129.9 eV; Figure 6 b shows the high-resolution XPS spectrum of Fe element, which shows a high Fe 3+ concentration, and in the C1s XPS spectrum ( Figure 6 In c), FcP· detects the CN bond; Figure 6 d is the high-resolution XPS spectrum of the N element. It can be seen that after covalent modification, PC bonds are displayed in the C1s and P2p XPS spectra, indicating that AFc is bound to BP through PCN bonds.

[0058] In order to further characterize the surface group structure of FcP· and verify whether the modification of AFc on the BP surface is successful, the raw materials black phosphorus, aminoferrocene and the resulting products used in this example were further characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and laser confocal Raman spectroscopy (Raman). The UV-Vis results are shown in Figure 2. Figure 7 As shown in a, BP has no obvious characteristic absorption peak in the range of 400-800nm, AFc has a UV absorption peak of ferrocenyl at 448nm, and FcP· has a ring-cyclopentadienyl absorption peak at 540nm. The UV absorption peak is red-shifted. The reason may be that after AFc is modified on BP, the conjugation range on the ring-cyclopentadienyl becomes larger, the probability of electronic transition increases, and thus the wavelength increases. FT-IR results are shown in Figure 7 As shown in b, in the AFc curve, 3396.63cm -1 , 3327.35cm -1 The two absorption peaks correspond to the stretching vibration peaks of -NH2 in AFc, 1497.54 cm -1 , 1104.41cm -1The characteristic absorption peak at 1254.53 cm comes from the stretching vibration of C=C. -1 The characteristic absorption peak at 810.37 cm is the stretching vibration of the CN bond. -1 The characteristic peak at 492.38 cm is attributed to the CH stretching vibration of the cyclopentadienyl ring. -1 The characteristic peak at 3419cm is the stretching vibration of the cyclopentadienyl ring and iron. Compared with BP, the spectrum of FcP· modified by AFc can be seen at 3419cm -1 、1646.07cm -1 、1380.99cm -1 、1078.74cm -1 、538.22cm -1 New characteristic peaks appeared at , which were attributed to NH, C=C, CN, CH, and Fe-C stretching vibrations, indicating that AFc was successfully modified on the BP surface. In particular, the vibration frequencies of the characteristic peaks in UV-Vis and FT-IR were shifted to high frequencies. The reason is that BP and AFc are connected by CPN bonds, where the CP bond length is This indicates the presence of a double bond. The CPN bond is directly connected to the cyclopentadienyl ring, which increases the conjugation range on the cyclopentadienyl ring. Therefore, the stretching vibration frequencies of the NH, C=C, and CH bonds all shift to higher frequencies. The Raman results are as follows: Figure 7 As shown in c, the spectrum of BP is at 361.49 cm -1 、436.60cm -1 and 464.59cm -1 There are three typical Raman peaks at 355.83 cm, which correspond to the characteristic peaks A1g, B2g and A2g modes of BP. -1 、429.12.8cm -1 、457.14cm -1 , the peak position of the A1g mode red-shifted by about 5 cm -1 , while the peak positions of A2g and B2g modes are red-shifted by about 8 cm -1 The reason for this phenomenon is that the two-dimensional BP lattice is chemically modified by AFc, which suppresses the oscillation of P atoms and reduces the corresponding Raman scattering energy. These results indicate that AFc is successfully modified onto the BP surface through covalent bonding.

[0059] The element mass ratio of C and N on the surface of the product obtained in this example was analyzed by CHNS element analyzer. The results are as follows: Figure 8As shown in the figure, the C content and N content in FcP· are 11.30wt% and 2.12wt%, respectively, with a mass ratio of 5.33:1, which is close to the mass ratio of C and N of 5.14 (C6N) in the theoretical structure. It can be seen that after AFc is modified on the BP surface, the original chemical structure of AFc has changed, and a cyclopentadienyl ring connected to Fe in AFc has dissociated.

[0060] The EPR spectra of the raw materials black phosphorus (BP), aminoferrocene (AFc) and the obtained product (FcP·) used in this example were measured using a paramagnetic electron resonance spectrometer (EPR). The results are as follows: Figure 9 As shown in the figure, no EPR signal was observed in BP and AFc, but an obvious EPR signal was observed in FcP·, indicating that free radicals were generated after AFc modified BP.

[0061] Based on the above characterization tests, the structural formula of the product prepared in this example is:

[0062]

[0063] The magnetic properties of the raw materials black phosphorus (BP), aminoferrocene (AFc) and the resulting product (FcP·) used in this example were tested using a vibrating sample magnetometer (VSM) at room temperature (25°C). The test magnetic field was between -20,000 Oe and 20,000 Oe. The obtained magnetization intensity and external magnetic field strength change curve (hysteresis loop) are shown as follows: Figure 10 As shown, FcP exhibits room-temperature ferromagnetism, and its magnetization increases with the increase of the applied magnetic field. When the applied magnetic field reaches 20,000 Oe, the saturation magnetization (Ms) value of the sample is 6.14 emu / g. Using inductively coupled plasma mass spectrometry (ICP-MS) to measure the Fe content in the product obtained in this embodiment, the Fe content is 2.44 wt%, and the calculated saturation magnetization per gram of Fe in the product is 2.51 emu / g. The saturation magnetization of SPIONs, a commonly used contrast agent at present, is about 70 emu / g (SPIONs), and its Fe content is 72.4 wt%, with the Ms per gram of Fe being 0.97 emu / g (Fe in SPIONs). In other words, under the condition of containing the same mass of Fe, the Ms of FcP is three times that of SPIONs.

[0064] The cytotoxicity test of FcP· prepared in this example was conducted as follows: macrophages in the logarithmic growth phase were taken and 100 μL per well were inoculated into a 96-well plate. The cell culture inoculation concentration was 1×10 4Cells were not inoculated around the outermost layer of the 96-well plate. An equal volume of PBS buffer (pH 7.6) was added to each well. Four replicate wells were reserved and 100 μL of DMEM complete medium (prepared by 1 vol% double antibody (penicillin and streptomycin mixture) plus 10 vol% serum plus 89 vol% DMEM high glucose medium) was added as blank zero wells. The inoculated 96-well plate was cultured in an incubator (37°C, 5% CO2) for 24 h. After the cells adhered, the original culture medium was replaced and serum-free DMEM medium was used as the solvent. The FcP prepared in this example was prepared to concentrations of 0 μg / mL, 25 μg / mL, 50 μg / mL, 100 μg / mL, and 100 μg / mL. mL, 200 μg / mL of material-containing culture medium, the material-containing culture medium with different sample concentrations was added to the well plate, 3 replicates were set for each concentration, 100 μL was added to each well, the well with a concentration of 0 μg / mL was used as the control group, and the cells were placed in an incubator (37°C, 5% CO2) and cultured for 24 h. After the culture was completed, the culture medium was aspirated, and 10 μL of 5 mg / mL MTT solution (PBS buffer as solvent) was added to each well. The cells were cultured in the incubator for 4 h. Blue crystals appeared in the wells, the liquid in the wells was aspirated, and 150 μL DMSO was added to each well. After slow shaking for 10 min to dissolve the precipitate, the absorbance of each well at 490 nm was measured with a microplate reader to calculate the cell survival rate. The comparison of cell survival rates under different concentrations of material-containing culture medium is shown in the figure. Figure 11 It can be seen that macrophages still have high cell activity when the FcP concentration is 400 μg / mL.

[0065] Example 2

[0066] Hyaluronic acid (HA) modified FcP (HA-FcP) was prepared by weighing 60 mg of HA powder into a beaker, adding 30 mL of deionized water, and magnetically stirring at room temperature overnight to fully dissolve the HA to obtain an HA aqueous solution. 20 mg of the FcP prepared in Example 1 was added to 10 mL of deionized water, ultrasonically dispersed, and then added to the HA aqueous solution. After magnetic stirring at room temperature for 4 hours, the resulting mixture was transferred to a centrifuge tube and centrifuged to remove excess HA. The mixture was then rinsed three times with deionized water and dried in a 40°C oven for 10 hours to obtain HA-FcP.

[0067] CD44 protein expression is significantly higher in vulnerable plaque areas than in healthy vascular tissue. Its endogenous ligand is hyaluronic acid. CD44 protein normally exists in a low-HA affinity conformation. In the inflammatory microenvironment of atherosclerotic plaques (e.g., TNF-α), CD44 protein transforms to a high-HA affinity state through post-translational modifications such as glycosylation. Therefore, modifying the FcP surface with hyaluronic acid can be used to detect vulnerable plaque areas.

[0068] The TEM image of hyaluronic acid modified FcP· prepared in this example is shown in FIG. Figure 12 As shown, the surface of the product is covered with vesicular HA.

[0069] The FT-IR spectrum of the hyaluronic acid modified FcP· prepared in this example is shown in FIG. Figure 13 As shown, the product showed the presence of COC bonds and enhanced CH bond strength, indicating that HA has been successfully modified on the FcP· surface.

[0070] In order to determine the T2 imaging effect of HA-FcP, the raw materials BP and HA-BP used in Example 1 (obtained by replacing FcP· in the above-mentioned method for preparing HA-FcP with an equal mass of BP), FcP· prepared in Example 1, and HA-FcP prepared in this example were ultrasonically dispersed in deionized water to prepare 2 mg / mL BP dispersion, HA-BP dispersion, FcP· dispersion, and HA-FcP dispersion. Deionized water was used as a blank control. The obtained BP dispersion, HA-BP dispersion, FcP· dispersion, HA-FcP dispersion, and deionized water were transferred to a nuclear magnetic resonance tube and a multi-slice, multi-echo (MSME) T2 imaging sequence MRI scan was performed on a 9.4T magnetic resonance scanner. The imaging parameters are as follows: TR 2500ms, TE 15ms, FOV 2.5cm×2.5cm, matrix 256×256, thickness 1mm. The T2 imaging figure is shown in FIG. Figure 14 As shown in a, it can be seen that compared with the blank group, the dark signal of the HA-FcP image is enhanced, the imaging effect is the most obvious, and its T2 imaging effect is significantly better than that of BP, HA-BP and FcP·.

[0071] To determine the relaxivity of HA-FcP, the HA-FcP prepared in this example was diluted at different concentrations in 200 μL of 1.5 wt% agarose gel to obtain final Fe concentrations of 0.02 mM, 0.04 mM, 0.08 mM, 0.16 mM, and 0.32 mM, respectively. The sample was transferred to an MRI tube and subjected to T2 imaging sequence MRI scanning using the aforementioned method. The T2 imaging images are shown in FIG. Figure 14 As shown in (b), the image gradually darkens as the Fe concentration in HA-FcP increases, and the imaging effect is enhanced with increasing concentration. The scanned images were transferred to a post-processing workstation, where the transverse relaxation time (T2) was measured using T2-mapping software. A linear relationship between the transverse relaxation time and the Fe concentration in HA-FcP was determined by fitting the transverse relaxation time with the concentration. The transverse relaxation rate (r2) was determined using linear fitting. Figure 14 c is the T2 relaxation rate test graph of HA-FcP. The r2 relaxation rate of HA-FcP was 32.66 mM obtained by drawing a fitting curve based on the measured T2 intensity.-1 s -1 .

[0072] Example 3

[0073] Macrophage membrane-encapsulated drug-modified FcP·(FcP-MVM / SV), the preparation method of which is as follows: 1 mL of simvastatin (SV) solution (4-5 mg / mL) and 1×10 8 The macrophage membranes extracted from 10 macrophages were mixed and then extruded back and forth using a 1 mL micro-extruder, sequentially passing through 400 nm, 200 nm, and 100 nm polycarbonate membranes, each extruded back and forth 20 times. The resulting preparation was collected as the MVM / SV solution. 5 mg of FcP prepared in Example 1 was added to 2 mL of the previously prepared MVM / SV solution, and the mixture was placed in a magnetic stirrer and stirred continuously for 4 h to obtain FcP-MVM / SV.

[0074] Macrophage membranes can use their natural homologous targeting properties to identify the microenvironment of atherosclerotic plaques. Based on this, the anti-atherosclerotic drug simvastatin (SV) can be wrapped in macrophage membranes, and membrane proteins can be used to actively target plaque macrophages, thereby achieving precise targeted delivery of the drug.

[0075] The TEM image of the macrophage membrane-encapsulated drug-modified FcP· prepared in this example is shown in FIG. Figure 15 As shown, there are spherical structures on the surface of the product, which are macrophage vesicle membranes wrapped with SV adsorbed on the surface of FcP·.

[0076] The FT-IR spectrum of the macrophage membrane-encapsulated drug-modified FcP· prepared in this example is shown in FIG. Figure 16 As shown, the product is between 1300 and 1000 cm -1 There are multiple peaks in the range, which are the stretching vibrations of COC, that is, the molecule contains ester groups, indicating that the macrophage vesicle membrane has been successfully adsorbed on the FcP· surface.

[0077] The above results show that the FcP· prepared in the embodiment of the present invention can be modified with targeting molecules to form a functionalized probe, which can achieve targeted positioning to the lesion site and has the advantages of fewer synthesis steps, mild reaction conditions and convenient operation.

[0078] The above are merely two embodiments of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, and such modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An aminoferrocene-modified black phosphorus complex containing stable free radicals, characterized in that: It is obtained by covalently modifying aminoferrocene on the surface of black phosphorus, and aminoferrocene and black phosphorus are bonded via PCN bonds. The complex contains stable free radicals and has room temperature ferromagnetism. Its molecular structure is shown in the following formula (I):

2. The aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 1, characterized in that: The aminoferrocene-modified black phosphorus complex containing stable free radicals has a layered structure of multi-layer nanosheet stacking, with 25 to 45 stacked layers, a size of 2 to 5 μm, a thickness of 15 to 25 nm, and P, C, N, and Fe elements uniformly distributed on the surface.

3. A method for preparing the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 1 or 2, characterized in that: The specific steps are as follows: 1) Weighing blocky black phosphorus, adding the blocky black phosphorus to N,N-dimethylformamide to obtain a black phosphorus mixture, and sequentially subjecting the obtained black phosphorus mixture to ultrasonication and ultrasonic water bath treatment to obtain a dark brown black phosphorus suspension; 2) Under inert atmosphere, the black phosphorus suspension obtained in step 1) is uniformly mixed with dichloromethane, and then aminoferrocene or a dichloromethane dispersion of aminoferrocene is added, oxygen and moisture in the system are removed, and the mixture is heated under reflux to react. After the reaction is completed, the solid phase product is separated, washed, and dried to obtain the product.

4. The method for preparing the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 3, wherein: The concentration of the black phosphorus mixed solution in step 1) is 0.5-2 mg / mL; the ultrasonic crushing treatment time in step 1) is 3-6 hours, and the water bath ultrasonic treatment time is 3-6 hours.

5. The method for preparing the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 3, wherein: Step 2) uniformly mixing the black phosphorus suspension with dichloromethane, wherein the volume ratio of the black phosphorus suspension to the dichloromethane is 0.5 to 1.5:1; in step 2), the mass of the aminoferrocene or the mass of the aminoferrocene in the dichloromethane dispersion of the aminoferrocene is 20 to 40% of the mass of the black phosphorus in the black phosphorus suspension, and the dichloromethane dispersion of the aminoferrocene is obtained by dispersing the aminoferrocene in dichloromethane, and the concentration is 4 to 12 mg / mL.

6. The method for preparing the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 3, wherein: Step 2) heating under reflux reaction conditions: reaction at 95-105°C for 8-12 hours.

7. Use of the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 1 or 2 as a contrast agent.

8. A probe based on the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 1 or 2, characterized in that: The black phosphorus complex modified with aminoferrocene containing stable free radicals is obtained by modification with targeted molecules.

9. The probe containing aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 8, characterized in that: The targeting molecules include one or more of hyaluronic acid, macrophage vesicle membrane, liposome, and statins.

10. Use of the probe based on the aminoferrocene-modified black phosphorus complex containing stable free radicals according to claim 8 as a contrast agent and a diagnostic and therapeutic agent.

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