A tungsten boride nano-heterojunction and a preparation method and application thereof

Abstract

The application discloses a kind of tungsten boride nano heterojunction, its preparation method includes the following steps: S1, tungsten boride powder is uniformly dispersed in ethylene glycol, and tungsten boride ethylene glycol solution is obtained;S2, the tungsten boride ethylene glycol solution obtained in S1 is added with glacial acetic acid and hydrogen peroxide, is fully stirred uniformly, and a mixed solution is obtained;S3, the mixed solution obtained in S2 is placed into microwave synthesis instrument and is subjected to microwave synthesis, after reaction, immediately take the upper solution and centrifugal, the solid product obtained after centrifugal, it is tungsten boride nano heterojunction.The tungsten boride nano heterojunction is synthesized by liquid phase stripping method in one step, ethylene glycol is used as reaction solvent, to provide higher reaction temperature for microwave synthesis reaction, in addition, acetic acid and hydrogen peroxide further react with tungsten boride, make compact tungsten boride nano structure loose, make nanometer sheet surface part oxidation into WO3, constitute heterojunction structure, first from top to bottom method obtains nanometer size tungsten boride heterojunction structure.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials, and specifically relates to a tungsten boride nanoheterostructure, its preparation method, and its application. Background Technology

[0002] The high chemical stability, excellent mechanical properties, and high melting temperature of tungsten boride are strong indicators of its great potential. In addition, it has been reported that superconductivity can be generated in borides through pressure-induced metastable planar defects. However, the density of tungsten boride prepared by borothermal reduction combined with spark plasma sintering (SPS) can reach more than 90%, which is attributed to the strong polarization of layered WB bonds. This weakens the shear slip initiation between layers, making it a hard material. Furthermore, the extreme chemical inertness and mechanical robustness of crystalline boron prevents its separation from the tungsten phase. Therefore, the preparation of nanoscale tungsten boride materials is currently very difficult.

[0003] Sound-sensitive agents are ultrasonic catalysts that exhibit a certain efficiency in generating reactive oxygen species (ROS) under ultrasound. Inorganic semiconductor nano-sound-sensitive agents possess characteristics such as low toxicity, high chemical stability, and controllable physicochemical properties under ultrasonic catalysis, and have been effectively applied in sonodynamic therapy. However, the rapid recombination of electrons and holes severely affects the SDT efficiency of semiconductor sound-sensitive agents. Currently, oxygen defect formation in materials is a commonly used method to improve the catalytic efficiency of sound-sensitive agents, but its drawback is that it is only applicable to metal oxide-based sound-sensitive agents and has limited effect on improving sound-sensitive performance. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a tungsten boride nanoheterojunction sound sensor and its preparation method, addressing the shortcomings of the existing technology. This invention synthesizes tungsten boride nanoheterojunctions in one step via a liquid-phase exfoliation method, using ethylene glycol as the reaction solvent to provide a higher reaction temperature for the microwave synthesis reaction. Furthermore, acetic acid and hydrogen peroxide further react with tungsten boride, loosening the dense tungsten boride nanostructure and partially oxidizing the surface of the nanosheets to WO3, thus forming a heterojunction structure. This is the first time a top-down method has been used to obtain nanoscale tungsten boride heterojunction structures.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows:

[0006] A tungsten boride nanoheterostructure (WOB) is prepared by the following steps:

[0007] S1. Disperse tungsten boride powder uniformly in ethylene glycol to obtain tungsten boride ethylene glycol solution;

[0008] S2. Add glacial acetic acid and hydrogen peroxide to the tungsten boride ethylene glycol solution obtained in S1, and stir thoroughly to obtain a mixed solution.

[0009] S3. Place the mixed solution obtained in S2 into a microwave synthesizer for microwave synthesis. After the reaction is completed, immediately take the upper layer solution and centrifuge it. The solid product obtained after centrifugation is tungsten boride nanoheterojunction.

[0010] According to the above scheme, in step S1, the concentration of the tungsten boride ethylene glycol solution is 0.5-2 mg / mL; the tungsten boride powder is micron-sized particles.

[0011] According to the above scheme, in step S2, the volume ratio of tungsten boride ethylene glycol solution, glacial acetic acid and hydrogen peroxide is 10:(0.01-0.02):(0.001-0.005); wherein the concentration of hydrogen peroxide is 0.05-0.15mM.

[0012] According to the above scheme, in step S3, the microwave synthesis temperature is 180-240℃, the power is in the range of 50-150w, and the microwave synthesis time is 4-12h.

[0013] According to the above scheme, in step S3, the centrifugation is high-speed centrifugation, with a speed of 8500-10000 rpm and a time of 10-30 min.

[0014] The tungsten boride nanoheterostructures prepared by the above method have a layered structure with a size of 50-150 nm and a thickness of 0.5-2 nm. The tungsten boride is partially oxidized to tungsten trioxide to form heterostructures, which have characteristic peaks of tungsten boride and tungsten trioxide and have good acoustic and dynamic properties.

[0015] The aforementioned tungsten boride nanoheterostructures (WOBs) can be used as sonosensitive agents for sonochemical reactions, especially for tumors such as gliomas in the glial cells. Specific application methods include the following steps:

[0016] (1) The tungsten boride nanoheterojunction prepared by the above method is dispersed in deionized water to obtain a tungsten boride nanoheterojunction dispersion;

[0017] (2) The tungsten boride nanoheterojunction dispersion obtained in step (1) is mixed with phospholipid-polyethylene glycol-sequence peptide (phospholipid-polyethylene glycol-RGD) at a certain mass ratio and reacted in a constant temperature oscillator for a period of time to obtain a tungsten boride nanoheterojunction (WOB) sound sensor with targeting function.

[0018] (3) The tungsten boride nanoheterojunction (WOB) acoustic sensitizer with targeting function obtained in step (2) is dispersed in cells (such as tumor cells) as an acoustic catalytic reagent to carry out acoustic chemical reaction and achieve the killing of tumor cells.

[0019] According to the above scheme, in step (1), the concentration of the tungsten boride nanoheterojunction dispersion is 0.1-0.8 mg / mL.

[0020] According to the above scheme, in step (2), the mass ratio of tungsten boride nanoheterojunction dispersion to phospholipid-polyethylene glycol-RGD is 1:1-4:1; the temperature of the constant temperature chamber is 24-55℃, and the shaking speed is 100-150 rpm. Specifically, the phospholipid-polyethylene glycol-RGD can be selected from DSPE-PEG2000-RGD, etc., which has the characteristic of targeting gliomas.

[0021] According to the above scheme, in step (3), the sonochemical reaction (SDT) is performed using ultrasound, specifically under conditions of 1-2.0 W / cm². 2 The sonication time is 1-15 min; the dispersion concentration of the acoustic catalytic reagent in cells as a tumor treatment agent is 50-200 μg / mL.

[0022] The technical concept of this invention is as follows:

[0023] First, this invention employs a microwave synthesis method to obtain tungsten boride nanoheterostructures. By combining the chemical reaction of acetic acid and hydrogen peroxide, high temperature and pressure, and microwave action, extremely small nanosheet structures of approximately 50nm-150nm with biological applications are successfully exfoliated from a top-down process onto a blocky tungsten boride structure with extremely high hardness and a dense structure. Ethylene glycol is used as the reaction solvent, and the microwave reaction process allows the reaction temperature to reach approximately 250℃, thus providing a high-temperature and high-pressure environment. Acetic acid and hydrogen peroxide molecules violently and randomly bombard the surface of the tungsten boride layer during the high-temperature and high-pressure process, causing its originally dense structure to become looser, until tungsten boride nanosheets are formed.

[0024] Then, tungsten boride nanosheets react rapidly with hydrogen peroxide in a high-temperature environment, causing partial oxidation of the nanosheet surface to WO3, forming a heterojunction structure. While pure tungsten trioxide can be used as a sound-sensing agent, its sound-sensing performance is extremely poor. However, the tungsten boride nanosheets synthesized in this invention undergo partial oxidation to obtain tungsten trioxide, forming a heterojunction structure. This results in excellent sound-sensing performance during application. Based on the principle of sonodynamic therapy, the heterojunction structure enhances electron transport rate, thereby reducing electron-hole recombination. Electrons and holes can react more efficiently with water and oxygen molecules in the environment to produce reactive oxygen species (ROS). Therefore, under ultrasound, WOB can act as a highly efficient sound-sensing agent, generating hydroxyl radicals (·OH) and singlet oxygen (·OH). 1 Reactive oxygen species (ROS) such as O2 are used in sonodynamic therapy to effectively induce tumor cell apoptosis and achieve good sonodynamic therapeutic effects.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention synthesizes tungsten boride nanoheterostructures in one step via a liquid-phase exfoliation method. Ethylene glycol is used as the reaction solvent to provide a higher reaction temperature for the microwave synthesis reaction. In addition, acetic acid and hydrogen peroxide further react with tungsten boride to loosen the dense tungsten boride nanostructures. This is the first time that a top-down method has been used to obtain nanoscale tungsten boride heterostructures.

[0027] Furthermore, from the perspective of acoustic sensitizers, tungsten trioxide is an acoustic sensitizer, but its acoustic sensitizing properties are limited and its therapeutic effect is poor. This invention synthesizes tungsten boride nanosheets with partial surface oxidation to obtain tungsten trioxide, forming nano-heterojunctions, reducing electron-hole recombination, and obtaining a novel acoustic sensitizer with extremely strong acoustic sensitizing properties. Under ultrasonic action, it can generate a large number of free radicals (·OH) and singlet oxygen (·OH). 1 Reactive oxygen species (ROS) such as O2 can be used for effective sonodynamic therapy of tumors. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope image of the raw material tungsten boride powder.

[0029] Figure 2 Transmission electron microscopy (TEM) images and high-resolution electron microscopy (HRTEM) images of the tungsten boride nanoheterojunction (WOB) prepared for the example.

[0030] Figure 3 An atomic force microscope image of the tungsten boride nanoheterojunction (WOB) prepared for the example.

[0031] Figure 4 The XRD diffraction patterns of the tungsten boride nanoheterostructure (WOB) prepared for the example are shown in the figure.

[0032] Figure 5 High-resolution XPS spectra of W 2p, O 1s, and B 1s of the tungsten boride nanoheterojunction (WOB) prepared for the example and the raw material tungsten boride powder.

[0033] Figure 6 The tungsten boride nanoheterojunction (WOB) prepared for the example, the raw material tungsten boride powder, and the ultraviolet absorption spectrum of WO3.

[0034] Figure 7 The acoustic-dynamic properties of the tungsten boride nanoheterojunction (WOB) prepared for this example are shown. Wherein, 'a' represents the acoustic-dynamic properties of the tungsten boride nanoheterojunction (WOB) under ultrasonic irradiation (40 kHz, 2.0 W / cm²). 2 The 50% duty cycle generates reactive oxygen species (ROS), leading to the degradation of DPBF over time; b represents the degradation of tungsten boride nanoheterostructures (WOB) under ultrasonic treatment (40kHz, 2.0W / cm²). 2 50% duty cycle) produces singlet oxygen ( 1O2) leads to an increase in the fluorescence of SOSG over time (SOSG is singlet oxygen). 1 O2) probe); c is tungsten boride nanoheterostructure (WOB) under ultrasonic irradiation (40kHz, 2.0W / cm). 2 The 50% duty cycle generates hydroxyl radicals (·OH), which leads to the degradation of MB over time (MB is a hydroxyl radical (·OH) probe).

[0035] Figure 8 The following describes the intracellular reactive oxygen species (ROS) generation of tungsten boride nanoheterostructures (WOBs) prepared for this example. Figures a and b show the flow cytometry analysis and quantitative analysis of intracellular ROS in human astroblastoma cells (U87) after different treatments (a: PBS group; b: PBS + ultrasound group; c: WOB group; d: WO3 + ultrasound group; e: WOB + ultrasound group). Figure c shows the ROS generation observed by confocal microscopy after different treatments (Hoechst is a nuclear dye; DCFH-DA is a ROS probe).

[0036] Figure 9 To investigate the biosafety and cell therapy efficacy of tungsten boron nanoheterostructures (WOBs) using a CCK-8 assay kit, the following data were presented: a) cell viability of different cell types (U87 human astrocytoblastoma cells, HBMEC human microvascular endothelial cells, and 4T1 mouse breast cancer cells) after 6 hours of co-incubation with WOBs; b) U87 cell viability after 6 hours of incubation with different ultrasonic powers and concentrations of the material; and c) U87 cell viability after different treatments (control: PBS group; US: PBS + ultrasound group; WOB: WOB group; WOB + US: WOB + ultrasound group).

[0037] Figure 10 To investigate the viability of U87 cells after different treatments (control: PBS group; US: PBS + ultrasound group; WOB: WOB group; WOB + US: WOB + ultrasound group), the staining results of live cells (green fluorescence) and dead or late apoptotic cells (red fluorescence) were obtained using confocal microscopy (Calcuim-AM is the live cell staining agent; PI is the dead cell staining agent).

[0038] Figure 11 Transmission electron microscopy (TEM) image of tungsten boride that was not successfully stripped. Detailed Implementation

[0039] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the present invention is not limited to the following embodiments.

[0040] The tungsten boride powder used in the following examples is as follows: Figure 1 As shown, these are micron-sized tungsten boride particles, ranging in size from 1 to 20 μm.

[0041] Example 1

[0042] 1. Preparation of tungsten boride nanoheterojunctions (WOBs)

[0043] (1) 10 mg of tungsten boride powder was dispersed in ethylene glycol and sonicated for 30 min to ensure uniform dispersion of tungsten boride in the ethylene glycol solution, resulting in a 1 mg / mL tungsten boride ethylene glycol solution. Then, 10 μL of glacial acetic acid and 1 μL of 0.1 mM H2O2 were added to 10 mL of the tungsten boride ethylene glycol solution. The mixed solution was then reacted in a microwave synthesizer for 4 h (200 °C, 100 W / cm²). -2 Afterwards, the microwave synthesizer was turned off, and the solution was allowed to cool naturally to room temperature. The upper layer of the solution was then immediately centrifuged (10,000 rpm / min, 10 min). The precipitate obtained by centrifugation was redispersed in water to obtain a dispersion of tungsten boride nanoheterojunction (WOB aqueous solution, concentration of 0.2 mg / mL).

[0044] 2. Characterization of tungsten boride nanoheterostructures (WOB)

[0045] like Figure 2 Transmission electron microscopy (TEM) images show that the tungsten boride nanoheterostructures prepared by the above liquid phase exfoliation method have a sheet structure with a size of 50-100 nm. Figure 2 In high-resolution electron microscopy, the corresponding lattice sizes of WO3 and WB are 0.37 nm and 0.213 nm, respectively, thus preliminarily determining the heterostructure structure of the tungsten boride nanoheterostructure (WOB); simultaneously combined with Figure 3 Atomic force microscopy (AFM) revealed that the thickness of the tungsten boride nanoheterostructure is approximately 1.3 nm.

[0046] XRD analysis was used to determine the composition, purity, and crystal structure of the obtained tungsten boride nanoheterojunctions. Figure 4As shown, the characteristic diffraction peaks with 2θ values ​​of 23.119°, 23.586°, 24.38°, 26.594°, and 34.155° correspond to (002), (020), (200), (120), and (202) of WO3 (PDF#43-1035), respectively, while the 2θ values ​​of 21.001°, 29.126°, 32.812°, 39.281°, 42.337°, 42.74°, 47.582°, 59.258°, 69.403°, and 70.0° correspond to (002), (020), (200), (120), and (202) of WO3 (PDF#43-1035). The characteristic diffraction peaks of 78, 73.431, 75.786, 79.288, 79.827 and 88.729 correspond to (004), (101), (103), (105), (112), (008), (107), (200), (213), (1110), (215), (208), (217), (1013) and (220) of WB, respectively (PDF#35-0738). The results show that the tungsten boride nanoheterojunction is partially oxidized during liquid phase exfoliation.

[0047] like Figure 5 The composition and chemical state of the WB crystals used were determined using XPS. In the figure, three characteristic peaks from W 4f, B 1s, and O 1s were observed on the pristine surface of the WB crystals. The three oxidation states of boron with binding energies of 192.4, 190.2, and 188.5 eV for the B1s level were identified as BO, BB, and WB bonds, respectively. Correspondingly, the two oxidation states of O1s level with binding energies of 532.3 and 530.9 eV were identified as BO and WO bonds, respectively. Compared to tungsten boride powder, the oxygen content of the liquid-phase exfoliated tungsten boride was significantly increased, indicating that oxidation occurred on the surface of the boride nanostructure, a finding confirmed by the chemical states of W, B, and O.

[0048] like Figure 6 The image shows the liquid UV-Vis absorption peaks of WOB, WO3, and WB. Compared to powdered WB, the absorption peaks of nanosheet WOB and WO3 are similar, with an absorption peak appearing at 326 nm, further demonstrating the successful synthesis of partially oxidized tungsten boride nanoheterojunctions.

[0049] 3. Study on the Acoustodynamic Properties of Tungsten Boride Nanoheterostructures (WOB)

[0050] To evaluate the acoustic-dynamic properties of tungsten boride nanoheterojunctions (WOBs), the commonly used 1,3-diphenylisobenzofuran (DPBF) molecular probe was used to monitor reactive oxygen species (ROS) generated by ultrasound-triggered WOBs. The generated ROS reacts with DPBF, leading to a decrease in the characteristic absorption at 416 nm in the UV-Vis-NIR spectrum. Specifically, 100 μL (0.1 mg / mL) of WOB aqueous solution was mixed with 2 mL (50 μg / mL) of DPBF ethanol solution, and then sonicated under the following conditions: 40 kHz, 2.0 W / cm². 2 50% duty cycle. For example... Figure 7 As shown in Figure a, in the presence of WOB, the characteristic peak intensity of DPBF at 416 nm was found to be significantly reduced, indicating that WOB can generate a large amount of ROS under ultrasonic irradiation.

[0051] In addition, the singlet oxygen fluorescent probe (SOSG) and methylene blue (MB) were used to investigate the singlet oxygen generated by WOB ultrasound triggering. 1 O2) and hydroxyl radicals (·OH). The specific procedure was as follows: 100 μL (0.1 mg / mL) of WOB methanol solution was mixed with 2 mL (1 μM) of SOSG methanol solution, and then sonicated under the following conditions: 40 kHz, 2.0 W / cm². 2 50% duty cycle; 100 μL (0.1 mg / mL) WOB aqueous solution and 2 mL (10 μg / mL) MB aqueous solution were mixed and subjected to ultrasonic treatment under the following conditions: 40 kHz, 2.0 W / cm 2 50% duty cycle. For example... Figure 7 As shown in b, after adding the SOSG probe to the WOB aqueous solution, the fluorescence signal of the solution with an excitation wavelength of 470 nm increased significantly with the increase of US irradiation time, indicating that US can stimulate WOB to produce fluorescence. 1 O2. Methylene blue (MB) was used as a probe to detect the formation of ·OH during SDT, because ·OH can oxidize MB to colorless MB-OH. With prolonged sonication, MB degradation in the WOB solution was significant, indicating that MB can generate ·OH under US irradiation. Figure 7 c).

[0052] 4. Intracellular reactive oxygen species generation in nanostructured heterostructures (WOBs) under ultrasound irradiation

[0053] In cell and in vivo experiments, DSPE-PEG2000-RGD was anchored to the surface of the nanoheterostructure through hydrophobic interactions, giving it excellent biocompatibility and tumor-targeting ability. The experiment used a tungsten boride nanoheterostructure to DSPE-PEG2000-RGD mass ratio of 4:1. The above-mentioned tungsten boride nanoheterostructure dispersion was mixed with DSPE-PEG2000-RGD and reacted in a constant-temperature shaker for 1 hour (37℃, 150 rpm / min) to obtain the tungsten boride nanoheterostructure (WOB) with targeting function. To detect ROS production in cancer cells and verify the mechanism of WOB as a sonosensitive agent in eradicating tumor cells under ultrasound irradiation, the commonly used fluorescent probe 2,7-dichlorofluorescein diacetate (DCFH-DA) staining was performed. The in vitro cell therapy experiment was divided into the following 5 groups: a: PBS group; b: PBS + ultrasound group; c: WOB group; d: WO3 + ultrasound group; e: WOB + ultrasound group. Specific procedures are as follows:

[0054] Confocal microscopy was used to monitor ROS production in different groups and the therapeutic effects of different treatments. U87 cells were first seeded into eight cell culture dishes (30 mm in diameter) and incubated for 12 h. Then, 2 mL of PBS (10 mM, pH 7.4) was added to the PBS group and the PBS + ultrasound group; 2 mL of DMEM medium containing WOB (200 μg / mL) was added to the WOB group and the WOB + ultrasound group; and 2 mL of DMEM medium containing WO3 (200 μg / mL) was added to the WO3 + ultrasound group. All cells were incubated at 37°C and 5% CO2 for 4 h. The cells were then replaced with fresh medium, and the ultrasound groups (b: PBS + ultrasound group; d: WO3 + ultrasound group; e: WOB + ultrasound group) were sonicated (40 kHz, 2 W / cm²). 2 After treatment (10 min, 50% duty cycle), Hoechst 33342 and DCFH-DA staining agents were added to the cell dishes and incubated for 30 min. The cells were then imaged using a confocal laser scanning fluorescence microscope.

[0055] like Figure 8 c. No obvious green fluorescence was found in group ac. However, green fluorescence was found in groups d and e, and the fluorescence intensity in group e was significantly higher than that in group d, indicating that WO3 has certain acoustic sensitivity properties. The tungsten boride nanoheterojunction (WOB), due to the heterostructure formed by partial oxidation of the surface, effectively reduces the recombination of electrons and holes, thereby increasing the yield of ROS during the acoustic dynamic process.

[0056] In addition, flow cytometry has also been used to quantitatively detect the production of reactive oxygen species in U87 cells during ultrasound administration, such as... Figure 8As shown in a and b, similar to the results of confocal microscopy, the fluorescence intensity of the WOB+ultrasound group was significantly improved compared to other groups, further demonstrating the excellent acoustic sensitivity of WOB.

[0057] 5. Research on the biosafety and tumor cell killing effect of nanosheet WOB

[0058] Based on the efficient acoustic dynamic properties of WOB, its in vitro anticancer activity was further evaluated. Figure 9 Good biocompatibility is fundamental to the application of nanomaterials in biomedicine. The cytotoxicity of WOB to different cell types (U87 human astrocytoblastoma cells, HBMEC human brain microvascular endothelial cells, and 4T1 mouse breast cancer cells) was investigated using a CCK-8 assay kit. Figure 9 a represents the cell activity of different cells after co-incubating nanosheets of different concentrations (taking the concentration range of 0-200 μg / mL as an example) for 4 hours. It can be seen that when the concentration of WOB is as high as 200 μg / mL, the cytotoxicity of the material is negligible, indicating that the synthesized WOB has good biocompatibility.

[0059] Next, the killing effect of WOB on U87 cells under ultrasound was further evaluated. First, for in vitro sonodynamic therapy, nanosheets of different concentrations (0-200 μg / mL) were used, along with different powers (0-2.0 W / cm²). 2 To further evaluate the efficacy of WOB sonodynamic therapy using ultrasound, the specific procedures were as follows: U87 cells were first seeded into eight cell culture dishes (30 mm in diameter) and incubated for 12 hours. Then, DMEM medium containing different concentrations of WOB (0-200 μg / mL) was added to each dish, and the cells were incubated at 37°C and 5% CO2 for 4 hours. The cells were then replaced with fresh medium, and the experimental groups were subjected to different power levels (0-2.0 W / cm²). 2 Cells were treated with sonication (40 kHz, 10 min, 50% duty cycle), then digested with trypsin, rapidly transferred to 96-well plates, and incubated again for 24 h. Cell viability was finally tested using CCK-8 assay.

[0060] Next, the four experimental groups with different treatments were further tested using the standard CCK-8 method. U87 cells were first seeded onto eight cell culture dishes (30 mm in diameter) and incubated for 12 hours. Then, DMEM medium containing WOB (200 μg / mL) was added to the WOB group and the WOB + sonication group, and they were incubated at 37°C and 5% CO2 for 4 hours. The cells were then replaced with fresh medium and sonicated (40 kHz, 2.0 W / cm²). 2Cells were treated with a 10-minute, 50% duty cycle, then digested with trypsin, rapidly transferred to 96-well plates, and incubated again for 24 hours. Cell viability was finally tested using CCK-8 assay.

[0061] like Figure 9 As shown in b, cell viability was detected using a CCK-8 assay kit. With increasing ultrasound power and WOB concentration, the cell viability of U87 cells significantly decreased, indicating the good sonodynamic therapeutic effect of WOB. Furthermore, as... Figure 9 c. In different treatment experimental groups, the relative cell viability of group ac was greater than 90%, indicating that ultrasound irradiation and the WOB itself described in this invention did not cause damage to U87 cells. However, in experimental group d, when the WOB concentration was 200 μg / mL and the ultrasound power was 2.0 W / cm², the relative cell viability of group ac was greater than 90%, indicating that ultrasound irradiation and the WOB itself did not cause damage to U87 cells. 2 At that time, the cell viability of U87 cells was only 10.01%, which indicates that WOB has good killing effect on U87 cells under ultrasound.

[0062] Next, cells treated with different methods as described above using the CCK-8 method were co-stained with calcein-AM / PI (30 min) to detect live cells (green) and dead cells (red) in different experimental groups, and confocal microscopy was performed. The live / dead co-staining (AM / PI) revealed the killing effect of various treatments on U87 cells, further confirming the excellent killing effect of sonodynamic therapy on cancer cells. Figure 10 ).

[0063] Comparative Example

[0064] Microwave etching of bulk tungsten boride

[0065] (1) 10 mg of tungsten boride powder was dispersed in ethylene glycol and ultrasonically treated for 30 min to ensure uniform dispersion of tungsten boride in the ethylene glycol solution, yielding a 1 mg / mL tungsten boride ethylene glycol solution. The tungsten boride ethylene glycol solution was then reacted in a microwave synthesizer for 4 h (200 °C, 100 W / cm²). -2 Afterwards, turn off the microwave synthesizer and allow the solution to cool naturally to room temperature. Immediately take the supernatant and centrifuge (10000 rpm / min, 10 min). Redisperse the precipitate obtained by centrifugation in water, as follows: Figure 11 As shown in the transmission electron microscope image, the precipitate is still bulk tungsten boride, indicating that without the chemical reaction of acetic acid and hydrogen peroxide, microwave exfoliation alone cannot successfully remove bulk tungsten boride.

[0066] (2) Disperse 10 mg of tungsten boride powder in water and sonicate for 30 min to ensure uniform dispersion of tungsten boride in the aqueous solution, resulting in a 1 mg / mL tungsten boride aqueous solution. Then, add 10 μL of glacial acetic acid and 1 μL of H₂O₂ (0.1 mM) to 10 mL of the tungsten boride aqueous solution. Place the mixed solution in a microwave synthesizer and react for 4 h (100 °C, 100 W / cm²). -2 Afterwards, turn off the microwave synthesizer and allow the solution to cool naturally to room temperature. Immediately take the supernatant and centrifuge (10000 rpm / min, 10 min). Redisperse the precipitate obtained by centrifugation in water, as follows: Figure 11 As shown in the transmission electron microscope image (b), the precipitate is still bulk tungsten boride, indicating that the temperature and pressure provided by water as a solvent are insufficient to peel off the bulk tungsten boride.

[0067] Example 2

[0068] Preparation of tungsten boride nanoheterostructures (WOB)

[0069] (1) 10 mg of tungsten boride powder was dispersed in ethylene glycol and sonicated for 30 min to ensure uniform dispersion of tungsten boride in the ethylene glycol solution, resulting in a 1 mg / mL tungsten boride ethylene glycol solution. Then, 20 μL of glacial acetic acid and 2 μL of 0.1 mM H2O2 were added to 10 mL of the tungsten boride ethylene glycol solution. The mixed solution was then reacted in a microwave synthesizer for 6 h (220 °C, 80 W / cm²). -2 After that, the microwave synthesizer was turned off and the solution was allowed to cool naturally to room temperature. The upper layer of solution was then immediately centrifuged (8500 rpm / min, 20 min). The precipitate obtained by centrifugation was redispersed in water to obtain the dispersion of tungsten boride nanoheterojunction.

[0070] Example 3

[0071] Preparation of tungsten boride nanoheterostructures (WOB)

[0072] (1) 15 mg of tungsten boride powder was dispersed in ethylene glycol and sonicated for 30 min to ensure uniform dispersion of tungsten boride in the ethylene glycol solution, resulting in a 1.5 mg / mL tungsten boride ethylene glycol solution. Then, 15 μL of glacial acetic acid and 1.5 μL of 0.1 mM H2O2 were added to 10 mL of the tungsten boride ethylene glycol solution. The mixed solution was reacted in a microwave synthesizer for 8 h (180 °C, 150 W / cm²). -2 After that, the microwave synthesizer was turned off and the solution was allowed to cool naturally to room temperature. The upper layer of solution was then immediately centrifuged at high speed. The precipitate obtained by centrifugation was redispersed in water, which is the dispersion of tungsten boride nanoheterojunction (WOB aqueous solution).

[0073] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for preparing a tungsten boride nanoheterostructure, characterized in that... Includes the following steps: S1. Disperse tungsten boride powder uniformly in ethylene glycol to a concentration of 0.5-2 mg / mL to obtain a tungsten boride ethylene glycol solution; S2. Add glacial acetic acid and hydrogen peroxide to the tungsten boride ethylene glycol solution obtained in S1, and stir thoroughly to obtain a mixed solution; wherein, the volume ratio of tungsten boride ethylene glycol solution, glacial acetic acid and hydrogen peroxide is 10:(0.01-0.02):(0.001-0.005); S3. Place the mixed solution obtained in S2 into a microwave synthesizer for microwave synthesis. After the reaction is completed, take the upper layer solution and centrifuge it. The solid product obtained after centrifugation is tungsten boride nanoheterojunction, which has characteristic peaks of tungsten boride and tungsten trioxide.

2. The method for preparing a tungsten boride nanoheterostructure according to claim 1, characterized in that... In step S1, the tungsten boride powder is in the form of micron-sized particles.

3. The method for preparing a tungsten boride nanoheterostructure according to claim 1, characterized in that... In step S2, the concentration of hydrogen peroxide is 0.05-0.15 mM.

4. The method for preparing a tungsten boride nanoheterostructure according to claim 1, characterized in that... In step S3, the microwave synthesis temperature is 180-240℃, the power is in the range of 50-150w, and the microwave synthesis time is 4-12h.

5. The method for preparing a tungsten boride nanoheterostructure according to claim 1, characterized in that... In step S3, the centrifugation is high-speed centrifugation, with a speed of 8500-10000 rpm and a time of 10-30 min.

6. The tungsten boride nanoheterostructure prepared by the method of claim 1, characterized in that... The tungsten boride nanoheterojunction has a layered structure with a size of 50-150 nm and a thickness of 0.5-2 nm. Tungsten boride is partially oxidized to tungsten trioxide to form a heterojunction, which has characteristic peaks of both tungsten boride and tungsten trioxide.

7. The application of the tungsten boride nanoheterojunction according to claim 6 as a sound-sensing agent.

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