CN113499436B

CN113499436B - Molybdenum dioxide photoresponse nano material and preparation method and application thereof

Info

Publication number: CN113499436B
Application number: CN202110835434.3A
Authority: CN
Inventors: 郑婷婷; 王曾学; 陈辰; 孙鹏; 刘传国; 王晓钰; 郑冰清; 赵盼; 李伟; 张秀云; 冯玉; 罗黎; 王集会
Original assignee: Shandong University of Traditional Chinese Medicine
Current assignee: Shandong University of Traditional Chinese Medicine
Priority date: 2021-07-23
Filing date: 2021-07-23
Publication date: 2023-03-10
Anticipated expiration: 2041-07-23
Also published as: CN113499436A

Abstract

The application discloses a molybdenum dioxide photoresponse nano material and a preparation method and application thereof. The molybdenum dioxide photoresponse nano material is an oxygen defect molybdenum dioxide nano particle. The molybdenum dioxide photoresponse nano material has rich oxygen defects on the surface, has surface plasma resonance characteristics, shows strong wide-spectrum absorption in a biological first window and a biological second window, shows excellent photo-thermal conversion performance and photo-thermal stability after near-infrared laser irradiation, can generate a large amount of active oxygen after being excited by light, and has a very wide application prospect in photo-thermal treatment and photodynamic treatment.

Description

Molybdenum dioxide photoresponse nano material and preparation method and application thereof

Technical Field

The application relates to a molybdenum dioxide nano material and a preparation method and application thereof, belonging to the field of biomedical materials.

Background

Clinical treatment of tumors has been one of the major and difficult points in the field of biomedical research. Surgery, radiotherapy and chemotherapy are the main means for treating cancer in clinic at present, but these traditional treatment methods have a certain degree of damage to the immune system of the body while killing tumor tissues, and even cause the recurrence or metastasis of tumors. With the rapid development of the nanometer biotechnology, the functionalized nanometer material provides a new idea and means for anti-tumor treatment. Near-infrared laser-mediated tumor phototherapy, which has been proposed in recent years, has attracted extensive attention from the scientific community. The light-mediated tumor therapy is a minimally invasive therapy technology, utilizes the photoresponse nano material preparation to kill tumor cells by local hyperpyrexia or excitation of active oxidation species under the action of near-infrared laser, and has the advantages of high efficiency, minimally invasive property and small toxic and side effects. Currently, photothermal therapy (PTT) and photodynamic therapy (PDT) are widely used for cancer therapy as the two most prominent phototherapy methods for non-invasive therapy. Photothermal therapy is a therapeutic method in which a material with high photothermal conversion efficiency is injected into a human body, is focused near tumor tissues by using a targeting identification technology, and is irradiated by an external light source (generally near infrared light) to convert light energy into heat energy to kill cancer cells. The photodynamic therapy method is characterized in that when laser photons return to a ground state after laser irradiation, light energy is transferred to ambient oxygen to generate singlet oxygen, and the singlet oxygen is used as a strong oxidant to oxidize phospholipid on cell membranes and DNA in cell nuclei so as to oxidize, denature and inactivate the biomolecules, thereby achieving the purpose of treating tumors. The photothermal therapy and the photodynamic therapy have no harm to normal cells and tissues of a human body while killing tumor cells, and have the characteristics of high efficiency, rapidness, minimal invasion and small toxic and side effects. However, the research on the photo-thermal agents used in the current photo-thermal therapy and the photosensitizers used in the photo-dynamic therapy is mostly limited to the application to the biological first window (near infrared first region, 650 to 950 nm), but the biological second window (near infrared second region, 1000 to 1350 nm) photons have deeper tissue penetration ability than the near infrared laser of the biological first window.

The transition metal oxide is a representative of semiconductor photo-thermal conversion materials, and has the advantages of adjustable surface structure, high stability, cheap materials, simple preparation method and the like. Most of the transition metal oxide nano materials mainly focus on visible light or a biological first window in response to light, and have poor penetrating power and limited photons reaching a lesion part when applied to PTT and PDT treatment.

Therefore, in order to achieve deeper tissue penetration and reduce damage to healthy tissue in PTT and PDT treatments, it is of far-reaching interest to develop transition metal oxide photoresponsive nanomaterials with good near-infrared response.

Disclosure of Invention

In order to solve the above problems, in one aspect, the present invention provides a molybdenum dioxide photoresponse nanomaterial, wherein the molybdenum dioxide photoresponse nanomaterial is an oxygen-deficient molybdenum dioxide nanoparticle, the surface of the molybdenum dioxide photoresponse nanomaterial has abundant oxygen defects, has surface plasmon resonance characteristics, shows strong wide-spectrum absorption in a biological first window and a biological second window, and shows excellent photothermal conversion performance and photothermal stability after near-infrared laser irradiation, and the molybdenum dioxide photoresponse nanomaterial can generate a large amount of active oxygen after being optically excited.

The molybdenum dioxide photoresponse nanometer material is oxygen defect molybdenum dioxide nanometer particles.

Preferably, the particle diameter of the oxygen-deficient molybdenum dioxide nano particles is 10-100 nm.

Preferably, the oxygen-deficient molybdenum dioxide nanoparticles are monoclinic phase oxygen-deficient molybdenum dioxide crystals.

According to another aspect of the present invention, the present application provides a method for preparing a molybdenum dioxide photoresponse nanomaterial, comprising the following steps:

adding MoCl ₅ And mixing the aqueous solution with a polyvinylpyrrolidone (PVP) aqueous solution, adjusting the pH value of the mixed solution to a certain acidity, and reacting to obtain the oxygen-deficient molybdenum dioxide nanoparticles.

Preferably, the MoCl ₅ Mo [ V ] in aqueous solution]The amount of substance is 0.1-5.0 mmol.

Preferably, the MoCl ₅ Mo [ V ] in aqueous solution]The mass ratio of the polyvinylpyrrolidone to the polyvinylpyrrolidone is (10-150): 1.

Preferably, the polyvinylpyrrolidone is polyvinylpyrrolidone K30.

Preferably, the pH of the mixed solution is 0.9 to 6.0.

Preferably, the pH of the mixed solution is adjusted using HCl solution or NaOH solution.

Preferably, concentrated HCl solution or 6 mol% L is used ^-1 And adjusting the pH value of the mixed solution by using NaOH solution.

Preferably, the reaction temperature is 150-220 ℃; the reaction time is 4-24 h.

Preferably, after the reaction is finished, the reaction product is placed at room temperature, and centrifugal separation and washing are carried out, wherein the washing liquid used for washing is selected from a mixed liquid of ethanol and acetone.

According to another aspect of the present invention, there is provided a use of the above-mentioned molybdenum dioxide photoresponsive nanomaterial or the molybdenum dioxide photoresponsive nanomaterial prepared by the above-mentioned preparation method as a photothermal agent in photothermal therapy or as a photosensitizer in photodynamic therapy.

Benefits of the present application include, but are not limited to:

1. the molybdenum dioxide photoresponse nano material is an oxygen-deficient molybdenum dioxide nano particle, the surface of the molybdenum dioxide photoresponse nano particle has rich oxygen defects and has surface plasma resonance characteristics, strong wide-spectrum absorption is displayed in a biological first window and a biological second window, excellent photothermal conversion performance and photothermal stability are displayed after near-infrared laser irradiation, a large amount of active oxygen can be generated after the molybdenum dioxide photoresponse nano material is excited by light, and a cell experiment shows that the molybdenum dioxide photoresponse nano material has a very wide application prospect in photothermal therapy and photodynamic therapy.

2. According to the preparation method provided by the application, the molybdenum dioxide photoresponse nano material can be obtained through one-step hydrothermal reaction, the preparation method is simple and efficient, the yield is high, and the production cost is effectively reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is an X-ray diffraction (XRD) pattern of a molybdenum dioxide photoresponse nanomaterial prepared in an example of the present application.

FIG. 2 is an Infrared (IR) spectrum of a molybdenum dioxide photoresponse nanomaterial prepared in an example of the present application.

Fig. 3 is a Transmission Electron Microscope (TEM) image (a), a transmission electron microscope (B) image with different magnifications, a High Resolution Transmission Electron Microscope (HRTEM) image (C), and a Selected Area Electron Diffraction (SAED) image (D) of the molybdenum dioxide photoresponse nanomaterial prepared in the embodiment of the present application.

FIG. 4 is an X-ray photoelectron spectroscopy (XPS) chart (A) of a molybdenum dioxide photo-responsive nanomaterial prepared in an example of the present application and an X-ray photoelectron spectroscopy chart (B) of commercially available molybdenum dioxide; a Raman (Raman) spectrum comparison graph (C) of the molybdenum dioxide photoresponse nano material prepared in the embodiment of the application and commercially available molybdenum dioxide; the electron paramagnetic resonance spectrum (EPR) of the molybdenum dioxide photoresponse nanometer material prepared in the embodiment of the application is compared with that of commercially available molybdenum dioxide and molybdenum trioxide (D).

Fig. 5 is an ultraviolet-visible-near infrared (UV-VIS-NIR) spectrum of a molybdenum dioxide nanomaterial prepared according to an embodiment of the present application.

FIG. 6 is a Dynamic Light Scattering (DLS) particle size distribution graph (A) of the molybdenum dioxide photoresponsive nanomaterial prepared by changing the molar ratio of Mo [ V ] to PVP, and a correlation graph (B) of the particle size of the molybdenum dioxide photoresponsive nanomaterial prepared by the example of the application and the molar ratio of (Mo [ V ]: PVP).

Fig. 7 is a UV-VIS-NIR spectrum graph (a), a photothermal temperature rise graph (B), an optical photograph (C) and a thermal imaging graph (D) of the molybdenum dioxide photoresponse nanomaterial prepared in the examples of the present application and commercially available molybdenum dioxide formulated into solutions of different concentrations.

Fig. 8 is a stability test chart of the molybdenum dioxide photoresponse nanomaterial prepared in the embodiment of the application.

Fig. 9 (a) is a UV-VIS spectrum of degradation of 1,3-Diphenylisobenzofuran (DPBF) solution of molybdenum dioxide photo-responsive nanomaterial prepared in the example of the present application under the action of active oxygen, fig. 9 (B) is a UV-VIS spectrum of degradation of DPBF solution added with commercially available molybdenum dioxide, and fig. 9 (C) is a comparison graph of DPBF degradation by active oxygen generated by molybdenum dioxide photo-responsive nanomaterial prepared in the example of the present application and commercially available molybdenum dioxide.

FIG. 10 shows the survival rate of the oxygen-deficient molybdenum dioxide prepared by the present invention and co-incubated with hepatoma cells at different concentrations.

FIG. 11 (A-D) is a trypan blue staining photograph of the molybdenum dioxide photoresponse nanomaterial prepared in the example of the present application after co-incubation with hepatoma cells and irradiation for 0, 1,3, 5 minutes, respectively; FIG. 11 (E-F) is a trypan blue staining photograph of a commercial molybdenum dioxide nanomaterial incubated with hepatoma cells after irradiation for 0 and 5 minutes, respectively; after the cells are stained, the live cells and the dead cells are counted by using a counting plate, and the cell survival rate is calculated, and fig. 11 (G) is a comparison graph of the cell survival rate of the molybdenum dioxide photoresponse material prepared in the embodiment of the present application and the cell survival rate of the commercially available molybdenum dioxide nano material after the molybdenum dioxide photoresponse material and the cells are respectively acted on the cells by light.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The starting materials in the examples of the present application are all commercially available or self-made, unless otherwise specified.

The analysis method in the examples of the present application is as follows:

the phase structure of the sample was characterized by means of an X-ray powder diffractometer (Rigaku D/Max 2200 PC); observing the morphology characteristics and the granularity of the sample by using a transmission electron microscope (JSM 2010 Plus); observing the microstructure of the sample by using a high-resolution transmission electron microscope (Philips Tecnai 20U-TWIN); analyzing the surface atomic state of the sample by using X-ray photoelectron spectroscopy (ThermoFisher scientific, ESCALAB250Xi, USA); characterizing the absorption degree of the sample to light by using ultraviolet-visible-near infrared absorption spectrum (Hitachi, UH 4150); recording the infrared absorption of the sample by using Fourier transform infrared spectroscopy (NICOLET, FT-IR spectrometer); particle size distribution measurements were performed using a laser particle sizer (Brookhaven, zetapALS Instruments).

The molybdenum dioxide photoresponse nano material provided by the application is composed of oxygen defect molybdenum dioxide nano particles. The particle size of the oxygen-deficient molybdenum dioxide nano particles is adjustable and is 10-100 nm.

In order to obtain the molybdenum dioxide photoresponse nano material, the application provides a preparation method thereof, which comprises the following steps:

adding 0.1-5.0 mmol of MoCl ₅ Adding 7mL of distilled water for dissolution, and magnetically stirring for 30 minutes to obtain a solution A;

dissolving 0.1-2.0 g of PVP in distilled water, and magnetically stirring for 30 minutes to obtain a solution B;

the solution A and the solution B are thoroughly mixed with magnetic stirring and concentrated HCl or 6mol L ^-1 NaOH is used for adjusting the pH value of the mixed solution to 0.9-6.0, the mixed solution is filled into a reaction kettle (the filling degree is about 70 percent), and the reaction kettle is put into a baking oven and reacts for 4-24 hours at the temperature of 150-220 ℃;

and after the reaction is finished, taking out the reaction kettle, placing the reaction kettle to room temperature, fully and centrifugally washing the reaction product for multiple times by using an ethanol-acetone mixed solution to remove excessive PVP, and freeze-drying to obtain the molybdenum dioxide photoresponse nano material.

Example 1

When MoCl ₅ Mo [ V ] in aqueous solution]And when the mass ratio of the molybdenum dioxide to the polyvinylpyrrolidone is 50.

The XRD test result in figure 1 shows that the product prepared by the preparation method provided by the embodiment is monoclinic phase molybdenum dioxide crystal.

In the infrared spectrogram of FIG. 2, 944, 768, 740cm ^-1 The absorption peak is the stretching vibration absorption peak of the Mo-O bond, which also indicates that the molybdenum dioxide can be prepared by the preparation method provided by the embodiment.

FIGS. 3 (A) and 3 (B) show that the prepared product is nanoparticles, the dispersibility of the nanoparticles is good, and FIG. 3 (A) shows that the prepared nanoparticles have a particle size of about 35nm; FIG. 3 (C) shows clear lattice fringes analyzed for the (1) crystal plane and the (-1) crystal plane of monoclinic molybdenum dioxide, respectively; fig. 3 (D) shows that the constituent elements of the product produced by the production method of this example are Mo and O elements, and the C element and Cu element appeared as generated by the sample copper mesh.

Fig. 4 is a test comparison of molybdenum dioxide prepared in this example with commercially available molybdenum dioxide to demonstrate that the molybdenum dioxide prepared by the preparation method of this example is composed of oxygen deficient molybdenum dioxide nanoparticles. FIG. 4 (A) shows that, after the O1s spectrum is peaked, a greater proportion of the adsorbed oxygen is found in the molybdenum dioxide prepared herein, whereas the commercially available molybdenum dioxide of FIG. 4 (B) is based on lattice oxygen, which illustrates that the molybdenum dioxide prepared herein has a greater proportion of defective oxygen; the Raman spectrum of the molybdenum dioxide prepared herein in fig. 4 (C) exhibited distinct Raman vibrational peaks compared to commercially available molybdenum dioxide, indicating that the molybdenum dioxide prepared herein has oxygen defects; in fig. 4 (D), the molybdenum dioxide prepared by the present invention shows a strong EPR vibrational peak compared with commercially available molybdenum dioxide and commercially available molybdenum trioxide, which indicates that the molybdenum dioxide prepared by the present invention has oxygen defects.

FIG. 5 shows that the oxygen deficient molybdenum dioxide prepared by the present application has good absorption in both the near infrared region I (650 to 950 nm) and the near infrared region II (1000 to 1350 nm).

Example 2

Influence of the ratio of Mo [ V ] to PVP amount on the particle size of oxygen defect molybdenum dioxide

The mass ratio of Mo [ V ] to PVP is shown in Table 1.

TABLE 1

Sample numbering	Mo[Ⅴ]Mass ratio to PVP
		1	10
2	20
		3	50
4	100
		5	150

FIG. 6 (A) DLS particle size analysis shows that Mo [ V ] can be adjusted by: the molar ratio of PVP ensures that the hydration particle size of the prepared oxygen-deficient molybdenum dioxide nano particles is between 26 and 198nm, and the actual particle size is about 10 to 100nm (generally, the hydration particle size of the nano material is about 2 times of the actual particle size, which is consistent with the literature report and the TEM characterization result provided by the application figure 3); FIG. 6 (B) illustrates that, within a certain range, mo [ V ]: the smaller the molar ratio of PVP, the smaller the particle size of the prepared oxygen deficient molybdenum dioxide.

Example 3

Characterization of photothermal conversion Properties

The oxygen deficient molybdenum dioxide prepared in example 1 was prepared into solutions having concentrations of 0ppm, 10ppm, 25ppm, 50ppm and 100ppm, respectively, and commercially available molybdenum dioxide was prepared into a solution having a concentration of 100ppm, and the solutions were characterized by photothermal conversion properties, respectively.

As can be seen from fig. 7 (C), the aqueous dispersion of oxygen deficient molybdenum dioxide prepared herein is blue in color; as can be seen from FIG. 7 (A), the oxygen-deficient molybdenum dioxide aqueous dispersion of the present application has strong light absorption capacity from the visible region to the near infrared region II, and the absorption peak is gradually enhanced with the increase of the concentration, while the commercially available molybdenum dioxide has very low absorption in the near infrared region; as can be seen from FIG. 7 (B), under the irradiation of near infrared light of 808nm, the temperature rise of the oxygen-deficient molybdenum dioxide of the present application is obvious, the temperature rise capability is gradually enhanced with the increase of the concentration, and the delta T is up to 35 ℃, but the commercially available molybdenum dioxide has no temperature rise effect after being irradiated by the near infrared light.

Fig. 8 is a stability test chart of the oxygen-deficient molybdenum dioxide prepared by the present application after being heated by light, and it can be seen that the stability is still good after 10 cycles of heating and cooling. Since commercially available molybdenum dioxide has essentially no photothermal properties and thus no stability problems, its stability is no longer measured.

Example 4

Characterization of photodynamic Properties

The performance of oxygen-deficient molybdenum dioxide prepared in example 1 to generate active oxygen by 808nm near-infrared irradiation was tested by 1,3-Diphenylisobenzofuran (DPBF) reagent.

The specific experimental steps are as follows: 50. Mu.L of 8mM DPBF was added to 10mL of 100. Mu.g ^-1 The molybdenum dioxide nano photosensitizer is uniformly mixed, a DPBF solution of oxygen defect molybdenum dioxide is irradiated by a near infrared laser with the wavelength of 808nm, and the ultraviolet of the DPBF is measured every 10 minutes-visible absorption spectrum.

The performance of oxygen-deficient molybdenum dioxide for generating active oxygen is measured by the decrease of the ultraviolet absorption peak of DPBF at 410nm, and FIG. 9 (A) is a UV-VIS spectrogram of DPBF solution added with oxygen-deficient molybdenum dioxide prepared by the method for degrading under the action of active oxygen, and it can be seen that the oxygen-deficient molybdenum dioxide can generate active oxygen to obviously decrease the ultraviolet absorption peak of DPBF at 410nm after irradiation at different times; FIG. 9 (B) is a UV-VIS spectrum of the degradation of DPBF solution with commercial molybdenum dioxide, showing that the UV absorption peak at 410nm of DPBF remains substantially unchanged after different time of irradiation, indicating that commercial molybdenum dioxide is substantially incapable of generating active oxygen; FIG. 9 (C) compares the DPBF degrading ability of the oxygen deficient molybdenum dioxide with that of the commercially available molybdenum dioxide, wherein the DPBF degrading rate is 87% in 40 minutes and only 4% in 40 minutes. FIGS. 9 (A) - (C) illustrate that oxygen deficient molybdenum dioxide produced by the present application can generate a large amount of active oxygen.

From examples 3 and 4, the oxygen-deficient molybdenum dioxide nanoparticles prepared by the method show strong wide-spectrum absorption in a biological first window and a biological second window, show excellent photo-thermal conversion performance and photo-thermal stability after being irradiated by near-infrared laser, and can generate a large amount of active oxygen after being excited by light, so the oxygen-deficient molybdenum dioxide nanoparticles have very wide application prospects in photo-thermal treatment and photodynamic treatment.

Example 5

Cytotoxicity test

Inoculating 100 μ L of Hep G2 hepatocarcinoma cell maintenance medium (1%P/S, 2% FBS,97% DMEM) into 96-well plate, about 1 ten thousand cells per well, culturing in 37 deg.C incubator for 24 hr, washing with PBS, replacing maintenance medium containing oxygen-deficient molybdenum dioxide nano material with concentration of 0, 50, 100, 200, 300, 400, 500ppm, culturing for 24 hr, adding 10 μ L cck-8 per well, and adding 37 deg.C CO ₂ And culturing the incubator for 2h in the dark, taking out the 96-well plate, quickly putting the 96-well plate into an enzyme-labeling instrument, detecting absorbance at 450nm, and calculating the cell survival rate.

The cell viability was calculated as follows:

cell viability = (experimental-blank)/(control-blank) = 100%

FIG. 10 shows the survival rate of the cells after the co-incubation of the oxygen-deficient molybdenum dioxide obtained in the present embodiment with the hepatoma cells, wherein it can be seen that the survival rate of the cells is above 98% and there is no inhibition effect on the growth of the cells when the concentration of the oxygen-deficient molybdenum dioxide is 0-400 ppm; when the concentration of the oxygen-deficient molybdenum dioxide reaches 500ppm, the cell survival rate still maintains 88 percent. Therefore, the oxygen deficient molybdenum dioxide nanomaterial has no significant toxic effect on cell growth within a therapeutic dose.

Example 6

In vitro photothermal/photodynamic co-therapy test

And evaluating the effect of the oxygen-deficient molybdenum dioxide nano material on killing the liver cancer cells through the cooperation of photo-thermal/photodynamic by trypan blue live/dead cell staining experiments.

The specific test steps are as follows:

the Hep G2 cells are inoculated into a 96-well plate, placed into a thermostat at 37 ℃ for culturing for 24 hours, washed by PBS, replaced by a maintenance culture medium containing oxygen-deficient molybdenum dioxide nano material (100 pmm), continuously cultured for 12 hours, placed under a laser at 808nm for irradiating for 0, 1,3 and 5 minutes respectively, continuously cultured for 6 hours, stained by trypan blue, the number of live cells and dead cells is counted under a microscope by using a counting plate, and the cell survival rate is calculated. The killing effect of commercial molybdenum dioxide on liver cancer cells is tested by the same method.

FIG. 11 (A-D) is a trypan blue staining photograph of the oxygen-deficient molybdenum dioxide nanomaterial prepared by the present invention after co-incubation with hepatoma cells and irradiation for 0, 1,3, 5 minutes, respectively, from which it can be seen that the hepatoma cells gradually die with the increase of irradiation time; FIG. 11 (E-F) is a trypan blue staining photograph of a commercial molybdenum dioxide nanomaterial incubated with hepatoma cells after 0 and 5 minutes of irradiation, respectively, showing that the hepatoma cells are substantially all viable with prolonged irradiation time; the counting plate is used for counting and calculating to obtain the cell survival rate, and fig. 11 (G) is a comparison graph of the cell survival rate of the oxygen-deficient molybdenum dioxide nano material prepared by the method, the commercially available molybdenum dioxide nano material and the liver cancer cell after co-incubation and illumination, so that the liver cancer cell survival rate is below 7% after the cell co-incubated with the oxygen-deficient molybdenum dioxide is irradiated for 5 minutes, and the liver cancer cell survival rate is above 92% after the cell co-incubated with the commercially available molybdenum dioxide is irradiated for 5 minutes, which shows that the oxygen-deficient molybdenum dioxide prepared by the method has a good effect of inhibiting the growth of the cancer cell after the oxygen-deficient molybdenum dioxide is irradiated, and the commercially available molybdenum dioxide nano material basically has no obvious effect of inhibiting the growth of the cancer cell.

The above description is only an example of the present application, and the protection scope of the present application is not limited by these specific examples, but is defined by the claims of the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the technical idea and principle of the present application should be included in the protection scope of the present application.

Claims

1. The molybdenum dioxide photoresponse nano material is characterized in that the molybdenum dioxide photoresponse nano material is an oxygen-deficient molybdenum dioxide nano particle;

the preparation method of the molybdenum dioxide photoresponse nano material comprises the following steps:

adding MoCl ₅ Mixing the aqueous solution with a polyvinylpyrrolidone aqueous solution, adjusting the pH value of the mixed solution to acidity, and obtaining a molybdenum dioxide photoresponse nano material after the reaction is finished;

the MoCl ₅ Mo [ V ] in aqueous solution]The mass ratio of the polyvinylpyrrolidone to the polyvinylpyrrolidone is (10-150): 1.

2. The molybdenum dioxide photoresponsive nanomaterial according to claim 1, wherein the oxygen-deficient molybdenum dioxide nanoparticles have a particle size of 10-100 nm.

3. The molybdenum dioxide photo-responsive nanomaterial of claim 1, wherein the MoCl is ₅ Mo [ V ] in aqueous solution]The amount of the substance is 0.1-5.0mmol。

4. The molybdenum dioxide photoresponse nanomaterial according to claim 1, wherein the polyvinylpyrrolidone is polyvinylpyrrolidone K30.

5. The molybdenum dioxide photoresponse nanomaterial according to claim 1, characterized in that the pH value of the mixed solution is adjusted to 0.9-6.0.

6. The molybdenum dioxide photo-responsive nanomaterial according to claim 1, wherein the pH value of the mixed solution is adjusted using HCl solution or NaOH solution.

7. The molybdenum dioxide photoresponse nanomaterial according to claim 1, characterized in that the reaction temperature is 150-220 ℃; the reaction time is 4-24 h.

8. The molybdenum dioxide photoresponse nanomaterial according to claim 1, characterized in that after the reaction is finished, the reaction product is placed at room temperature for centrifugal separation and washing, and the washing solution used for washing is selected from a mixed solution of ethanol and acetone.

9. Use of the molybdenum dioxide photo-responsive nanomaterial of any of claims 1-8 in the preparation of a photothermal agent for photothermal therapy or a photosensitizer for photodynamic therapy.