Gold nano bipyramid / magnesium-aluminum hydrotalcite composite nano diagnosis and treatment agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biological medicines, and discloses a gold nano bipyramid / magnesium-aluminum hydrotalcite composite nano diagnosis and treatment agent as well as a preparation method and application thereof. The invention discloses a preparation method of a gold nano bipyramid / magnesium-aluminum hydrotalcite composite nano diagnosis and treatment agent, which comprises the following steps: 1) adding CTAB (Cetyltrimethyl Ammonium Bromide) and NaOL into water, after the CTAB and the NaOL are fully dissolved, adding HAuC l4 and AgNO3, then adding hydroquinone and a gold seed solution, and reacting to obtain a gold nano bipyramid; and 2) adding a NaOH / NaCO3 buffer solution into the AuNBPs dispersion liquid obtained in the step 1), dropwise adding a mixed solution of Mg (NO3) 2.6 H2O and Al (NO3) 3.9 H2O, and heating in a water bath to obtain the gold nano bipyramid / magnesium-aluminum hydrotalcite composite nano diagnosis and treatment agent. The gold nano bipyramid / magnesium-aluminum hydrotalcite composite nano diagnosis and treatment agent disclosed by the invention has relatively high photothermal conversion efficiency and a relatively good OCT (Optical Coherence Tomography) contrast effect, and can be used for photothermal therapy and biological imaging.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine technology, and in particular to a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent, and a preparation method and application thereof. Background Art

[0002] Cancer, also known as malignant tumor, how to carry out effective diagnosis and treatment of cancer has become a technical problem that needs to be solved urgently in this field.

[0003] Traditional cancer treatments in the medical field mainly include chemotherapy (chemotherapy), radiotherapy (radiotherapy) and surgical intervention. However, traditional treatments have certain limitations in treating tumors. Among them, chemotherapy and radiotherapy are not specifically selective for tumor cells. While acting on tumor cells, they also act on normal cells, which has great side effects on the human body. In addition, due to the adaptability of tumor cells, the treatment effect will gradually weaken. Surgical intervention is limited by the inability to clearly distinguish the boundaries of cancer tissue during the operation, which makes it very easy for tumor cells to metastasize and relapse after surgery.

[0004] In recent years, with the development of science and technology, researchers have developed many emerging tumor treatment methods, such as photodynamic therapy, photothermal therapy, ultrasound therapy and immunotherapy. Among them, photothermal therapy (PTT) has gradually been widely studied by researchers due to its advantages such as low invasiveness, precise selectivity and high efficiency of tumor destruction. It has become a new cancer treatment method with great clinical application potential.

[0005] Photothermal therapy is to inject photothermal agents (PTAs) into the body and enrich PTAs in the tumor site through blood circulation. Then, the tumor area is irradiated by a suitable external light source. PTAs can convert light energy into heat energy and destroy tumor cells through high temperature, thereby killing or inhibiting the tumor. However, the composition of solid tumors is very complex and differentiated. There are many types of malignant tumor cells that may occur in the body, and there are many undetermined gene mutations. Therefore, the tumor area of ​​the photothermal agent in the body will be limited by the volume and properties of the photothermal agent itself, and enriched in the area with high tumor blood vessel density, so that some tumor cells that are not heated enough can survive; moreover, the external light source selected for photothermal therapy will also affect the effect of photothermal therapy. For example, the penetration depth of laser light sources in certain bands is limited, resulting in the inability to kill tumor cells outside the irradiation depth; in addition, some photothermal agents have defects such as complex preparation process, high cost, and low photothermal conversion efficiency, which greatly limits the clinical application of photothermal therapy.

[0006] Gold nanomaterials have the advantages of excellent loading capacity, low biotoxicity and easy functional modification. Moreover, gold nanomaterials can achieve the conversion of light energy into thermal energy according to the irradiation of lasers of specific wavelengths. Therefore, gold nanomaterials show good applicability in photothermal therapy. However, after gold nanomaterials were prepared as photothermal agents, it was found that the photothermal conversion efficiency of gold nanophotothermal agents was low and the photothermal therapy effect was poor. Therefore, providing a gold nanodiagnostic and therapeutic agent with high photothermal conversion efficiency that can be used for photothermal therapy has become a technical problem that needs to be urgently solved by technicians in this field.

[0007] In addition, Optical Coherence Tomography (OCT) is a new imaging technology with the advantages of non-contact, non-destructive, high image resolution, simple operation and portability. It can be well applied to biomedical imaging and related diagnosis. Moreover, OCT technology can well make up for the shortcomings of low penetration depth of confocal microscope imaging and low resolution of ultrasonic imaging. At present, OCT technology provides an important basis for early diagnosis, surgical guidance and postoperative rehabilitation of cardiovascular diseases, gastrointestinal diseases and cancer in clinical practice.

[0008] Based on this, if the gold nanophotothermal agent that can be used for photothermal therapy can also be used as an OCT contrast agent to enhance the effect and signal intensity of OCT imaging, that is, to achieve the integration of OCT imaging diagnosis and photothermal therapy, it will be expected to further carry out effective diagnosis and treatment of cancer. Summary of the invention

[0009] The purpose of the present invention is to provide a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent and its preparation method and application. The gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent has a high photothermal conversion efficiency and can be used for photothermal therapy and bioimaging.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] One of the technical solutions of the present invention:

[0012] A method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent comprises the following steps:

[0013] 1) Preparation of gold nanobipyramids:

[0014] Add CTAB and NaOL into water, add HAuC l4 and AgNO3 after they are fully dissolved, then add hydroquinone and gold seed solution, react to obtain gold nanobipyramids, and disperse and store in deionized water;

[0015] 2) Preparation of gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent:

[0016] Add NaOH / NaCO3 buffer to the AuNBPs dispersion obtained in step 1), and dropwise add a mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O, heat in a water bath to obtain the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent, and vacuum freeze-dry into powder for storage.

[0017] Furthermore, in step 1), the concentration of HAuC 14 is 25 mmol / L, the concentration of AgNO 3 is 4 mmol / L, and the concentration of hydroquinone is 0.1 mol / L.

[0018] Furthermore, in step 1), the mass volume ratio of CTAB, NaOL, water, HAuC l4, AgNO3, hydroquinone and gold seed solution is 1.8-1.85 g: 55-60 mg: 35-40 mL: 0.4-0.6 mL: 2-2.5 mL: 8-12 mL: 50-300 μL.

[0019] Furthermore, in step 1), before adding hydroquinone and gold seed solution, the solution needs to be stirred until it changes from yellow to colorless, and 0.4-0.6 mL of 1 mol / L HCl is added to adjust the pH of the solution.

[0020] Furthermore, in step 1), the reaction is specifically: first stirring for 30 seconds, and then standing at 25° C. to react overnight.

[0021] Furthermore, in step 1), after the reaction is completed, the solution needs to be centrifuged at 7800 rpm for 10 minutes.

[0022] Furthermore, in step 2), the pH of the NaOH / NaCO3 buffer solution is 10.

[0023] Furthermore, in step 2), before adding the mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O, the solution needs to be heated to 65°C.

[0024] Furthermore, in step 2), the mass concentration of Mg(NO3)2·6H2O in the mixed solution of Mg(NO3)2·6H2O is 10-11 mg / mL, and the mass concentration of Al(NO3)3·9H2O is 7-8 mg / mL.

[0025] Furthermore, in step 2), the volume ratio of the NaOH / NaCO3 buffer, the AuNBPs dispersion and the mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O is 40mL:5mL:5mL.

[0026] Furthermore, in step 2), the water bath heating is specifically: the temperature of the water bath is maintained at 65° C., and the stirring and heating are continued for 6 hours.

[0027] Furthermore, in step 2), after the water bath heating is completed, the solution needs to be centrifuged at 7800 rpm for 5 minutes.

[0028] The second technical solution of the present invention:

[0029] The gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic and therapeutic agent is prepared by the preparation method of the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic and therapeutic agent.

[0030] The third technical solution of the present invention:

[0031] The above-mentioned gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic and therapeutic agent is used in photothermal therapy.

[0032] The fourth technical solution of the present invention:

[0033] The above-mentioned gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic and therapeutic agent is used in OCT imaging.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent provided by the present invention not only inherits the photothermal properties of AuNBPs by combining AuNBPs with Mg-Al LDH, but also accumulates free electrons in AuNBPs due to the introduction of Mg-Al LDH, enhances the LSPR effect, and promotes the conversion of light energy into heat energy; and the introduction of Mg-Al LDH effectively limits the Brownian motion of electrons in AuNBPs when heated, thereby significantly improving its photothermal conversion efficiency. According to calculations, the photothermal conversion efficiency of AuNBPs / Mg-Al LDH is as high as 63.4%, which is significantly improved compared with AuNBPs;

[0036] The gold nanobipyramid / magnesium-aluminum hydrotalcite composite nano-diagnostic agent provided by the present invention, when combined with 808nm laser irradiation, the survival rate of MCF-7 cells dropped sharply to 21.9% in 10 minutes, which strongly verified the excellent photothermal therapeutic effect of AuNBPs / Mg-Al LDH. Therefore, AuNBPs / Mg-Al LDH can be used for photothermal therapy;

[0037] The gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent provided by the present invention significantly enhances the effect and signal intensity of OCT imaging by compounding AuNBPs with Mg-Al LDH. Therefore, AuNBPs / Mg-Al LDH can be used for biological imaging.

[0038] In summary, the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent provided by the present invention has excellent photothermal therapy performance and significant advantages in OCT imaging. It is a highly potential multifunctional diagnostic agent and shows broad application prospects.

[0039] The present invention provides a method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent, which adopts a one-pot synthesis method, takes AuNBPs as the core, and induces Mg-Al LDH to grow in an intercalation manner around the surface of AuNBPs, thereby preparing AuNBPs / Mg-Al LDH; the one-pot synthesis method provided by the present invention not only simplifies the preparation process, but also ensures the integrity of the AuNBPs / Mg-Al LDH structure and the stability of the performance, and finally achieves the improvement of the photothermal conversion efficiency of the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent;

[0040] The present invention provides a method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent, which utilizes the interlayer ion exchangeability of LDH materials to make up for the shortcomings of single precious metal materials, thereby achieving an improvement in the photothermal conversion efficiency of the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0042] Figure 1 : are electron microscopy characterization result diagrams of AuNBPs, Mg-Al LDH and AuNBPs / Mg-Al LDH, wherein A is the electron microscopy characterization result diagram of AuNBPs, B is the electron microscopy characterization result diagram of Mg-Al LDH, and C is the electron microscopy characterization result diagram of AuNBPs / Mg-Al LDH;

[0043] Figure 2 The temperature-time test results of AuNBPs, Mg-Al LDH and AuNBPs / Mg-Al LDH are shown;

[0044] Figure 3This is the result of the in vitro photothermal therapy test of AuNBPs / Mg-A l LDH;

[0045] Figure 4 To simulate the OCT imaging of real tissue, A is the simulated real tissue OCT imaging, B is the simulated real tissue OCT imaging embedded in PEG, C is the simulated real tissue OCT imaging embedded in AuNBPs, and D is the simulated real tissue OCT imaging embedded in AuNBPs / Mg-Al LDH. DETAILED DESCRIPTION

[0046] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0047] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0048] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0049] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0050] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0051] In the following examples, the preparation of the gold seed solution comprises the following steps:

[0052] Prepare 8 mL of 66 mmol / L CTAC solution, then add 80 μL (microliter) of 25 mmol / L HAuC l4 solution and 74 μL of 25 mmol / L HNO3 solution to the CTAC solution, stir for 15 minutes, and finally add 100 μL of freshly prepared NaOH-NaBH4 mixed solution (v:v=1:1) and 100 μL of 1 mol / L sodium citrate solution in sequence under stirring conditions, stir for 2 minutes, and place in a water bath at 80 ° C for 1 hour to obtain the gold seed solution.

[0053] In the following examples, other raw materials used were commercially available.

[0054] In the following examples, the room temperature is 25±2°C.

[0055] Example

[0056] Preparation of gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic and therapeutic agent

[0057] 1) Preparation of gold nanobipyramids (AuNBPs):

[0058] 1.82 g CTAB and 58 mg NaOL were added to 38 mL deionized water. After fully dissolved, 0.5 mL HAuCl4 (25 mmol / L) and 2.25 mL AgNO3 (4 mmol / L) were added. After stirring until the solution changed from yellow to colorless, 0.5 mL HCl (1 mol / L) was added to adjust the pH of the solution. Then, 10 mL hydroquinone solution (0.1 mol / L) and 200 μL gold seed solution were added. After stirring for 30 s, the mixture was allowed to react overnight at 25 °C.

[0059] After the reaction, the solution was centrifuged at 7800 rpm for 10 min and washed three times with deionized water to obtain gold nanobipyramids. 0.2mg / mL, Dispersed and stored in deionized water;

[0060] 2) Preparation of gold nanobipyramid / magnesium aluminum hydrotalcite composite nanodiagnostic agent (AuNBPs / Mg-Al LDH):

[0061] Add 40 mL of NaOH / NaCO3 buffer (pH = 10) to 5 mL of the AuNBPs dispersion obtained in step 1), heat the solution to 65°C, slowly drop 5 mL of a mixed solution of Mg(NO3)2·6H2O (m = 51.3 mg) and Al(NO3)3·9H2O (m = 37.5 mg) while stirring, then maintain the temperature of the water bath at 65°C, and continue stirring and heating for 6 h;

[0062] After the water bath heating was completed, the solution was centrifuged at 7800 rpm for 5 min, and washed three times with deionized water to obtain the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent, which was vacuum freeze-dried into powder for storage.

[0063] Comparative Example

[0064] Preparation of Magnesium-Aluminum Hydrotalcite Nanomaterials (Mg-Al LDH)

[0065] Add 40 mL of NaOH / NaCO3 buffer (pH = 10) to 5 mL of aqueous solution, heat the solution to 65°C, slowly add 5 mL of a mixed solution of Mg(NO3)2·6H2O (m = 51.3 mg) and Al(NO3)3·9H2O (m = 37.5 mg) while stirring, then maintain the temperature of the water bath at 65°C and continue stirring and heating for 6 h.

[0066] Effect verification

[0067] 1. TEM characterization

[0068] The AuNBPs prepared in step 1) of the embodiment were characterized by transmission electron microscopy (TEM, Tecnai G220S, FEI). The results of the electron microscopy characterization of the AuNBPs are as follows: Figure 1 As shown in A;

[0069] Depend on Figure 1 As shown in A, the AuNBPs with an aspect ratio of 3 were successfully prepared in step 1) of the embodiment, and the AuNBPs prepared in step 1) of the embodiment can be used as the basic material for the subsequent preparation of AuNBPs / Mg-Al LDH;

[0070] The Mg-Al LDH prepared in the comparative example was characterized by a transmission electron microscope (TEM, Tecnai G220S, FEI). The electron microscope characterization results of the Mg-Al LDH are as follows: Figure 1 As shown in B;

[0071] Depend on Figure 1 As shown in Figure B, the Mg-Al LDH prepared in the comparative example has a unique uniform flaky structure. Studies have shown that this uniform flaky structure is composed of Mg 2+ and Al 3+ The result of interlayer intercalation;

[0072] The AuNBPs / Mg-Al LDH prepared in the example was characterized by transmission electron microscopy (TEM, Tecnai G220S, FE I). The results of the electron microscopy characterization of AuNBPs / Mg-Al LDH are shown in FIG. Figure 1 As shown in C;

[0073] Depend on Figure 1 As shown in Figure C, Mg-Al LDH successfully coated AuNBPs, and after embedding AuNBPs into Mg-Al LDH, the structure of Mg-Al LDH was still clearly visible, which indicated that the introduction of AuNBPs did not change the basic crystal framework of Mg-Al LDH;

[0074] Further studies have shown that because Mg-Al LDH wraps AuNBPs between layers, it promotes the excitation and accumulation of free electrons on the surface of AuNBPs. These active electrons enhance the LSPR effect under laser irradiation, promote the conversion of light energy into thermal energy, and thus improve the photothermal conversion efficiency.

[0075] 2. Photothermal characteristics detection

[0076] The AuNBPs prepared in step 1) of the embodiment, the Mg-Al LDH prepared in the comparative example, and the AuNBPs / Mg-Al LDH prepared in the embodiment were subjected to photothermal property testing;

[0077] The photothermal property detection method is as follows: 2 mL of AuNBPs, Mg-Al LDH and AuNBPs / Mg-Al LDH were placed in centrifuge tubes respectively, and then the 2 The 808nm laser was used to irradiate the sample and the temperature change of the sample over time was recorded. The temperature-time detection results are shown in Figure 2 As shown;

[0078] Depend on Figure 2 It can be seen that AuNBPs are exposed to 2.0W / cm 2 After irradiation with 808nm laser for 20min, ΔT was only 33.4℃. 2 After irradiation with 808 nm laser for 20 min, ΔT was only 9.3 °C. 2 After irradiation with 808nm laser for 20min, ΔT reached 56.8℃, showing a higher temperature rise than AuNBPs.

[0079] Studies have shown that the excellent photothermal properties of AuNBPs / Mg-Al LDH are a direct reflection of the synergistic effect between its components, AuNBPs and Mg-Al LDH. Although the direct concentration of AuNBPs in 1 mg / mL AuNBPs / Mg-Al LDH is less than 1 / 10, which is lower than the overall concentration, its photothermal heating efficiency is significantly better than that of AuNBPs. This performance enhancement is derived from the unique electron accumulation caused by the interaction between AuNBPs and Mg-Al LDH during the composite construction process. These electrons enhance the LSPR effect and effectively promote the conversion of light energy into thermal energy. The core-shell structure formed by Mg-Al LDH and AuNBPs constrains the Brownian motion of electrons in AuNBPs during heating, reduces unnecessary heat loss, and significantly improves the photothermal heating performance. This further confirms that AuNBPs / Mg-Al LDH has better photothermal properties; after calculation, the photothermal conversion efficiency of AuNBPs / Mg-AlLDH is as high as 63.4%, which is significantly improved compared with AuNBPs.

[0080] 3. Detection of the effect of extracorporeal photothermal therapy

[0081] MCF-7 cells were selected to test the in vitro photothermal therapy effect of AuNBPs / Mg-Al LDH prepared in Example. The results of the in vitro photothermal therapy effect test of AuNBPs / Mg-Al LDH are shown in Figure 2. Figure 3 As shown;

[0082] Depend on Figure 3 It can be seen that the blank control group was exposed to 2.0W / cm 2 After irradiation with 808 nm laser for 10 min, the survival rate of MCF-7 cells was 87%, which indicates that laser alone has almost no killing effect on MCF-7 cells; while AuNBPs / Mg-Al LDH was co-incubated with cells and exposed to 2.0 W / cm 2 After irradiation with 808nm laser for 10min, when the concentrations of AuNBPs / Mg-Al LDH were 0.25, 0.5, 0.75 and 1mg / mL respectively, the survival rate of MCF-7 cells showed a significant downward trend with the increase of AuNBPs / Mg-Al LDH concentration. When the concentration of AuNBPs / Mg-Al LDH was 1mg / mL, the survival rate of MCF-7 cells dropped sharply to 21.9%, which strongly verified the excellent photothermal therapy effect of AuNBPs / Mg-Al LDH. Therefore, AuNBPs / Mg-Al LDH can be used as a photothermal agent under 808nm laser irradiation.

[0083] 4. OCT imaging analysis simulating real tissue

[0084] PEG, AuNBPs prepared in step 1) of the embodiment, and AuNBPs / Mg-Al LDH prepared in the embodiment were embedded in the simulated real tissue, and OCT imaging analysis was performed on the simulated real tissue. The OCT imaging of the simulated real tissue is as follows: Figure 4 As shown, A is the simulated real tissue OCT imaging, B is the simulated real tissue OCT imaging embedded in PEG, C is the simulated real tissue OCT imaging embedded in AuNBPs, and D is the simulated real tissue OCT imaging embedded in AuNBPs / Mg-Al LDH;

[0085] Depend on Figure 4 It can be seen that the simulated real tissue has no OCT imaging effect. After embedding in PEG, the OCT imaging effect is not obvious. After embedding in AuNBPs and AuNBPs / Mg-Al LDH, the OCT imaging effect is enhanced, and the OCT imaging effect of embedding in AuNBPs / Mg-Al LDH is significantly enhanced compared with AuNBPs.

[0086] Studies have shown that the significant enhancement of AuNBPs / Mg-Al LDH imaging is attributed to the substantial increase in the light scattering surface area of ​​AuNBPs after they are combined with Mg-Al LDH, thereby enhancing the intensity of backscattered light and providing richer signal feedback for imaging.

[0087] In addition, the simulated real tissue embedded with AuNBPs / Mg-Al LDH had OCT imaging from the surface to the deep regions, which further confirmed the effectiveness of AuNBPs / Mg-Al LDH in enhancing OCT imaging.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent, characterized in that: The following steps are involved: 1) Preparation of gold nanobipyramids: Add CTAB and NaOL into water, add HAuCl4 and AgNO3 after they are fully dissolved, then add hydroquinone and gold seed solution, react to obtain gold nanobipyramids, and disperse and store in deionized water; 2) Preparation of gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent: Add NaOH / NaCO3 buffer to the AuNBPs dispersion obtained in step 1), and drop a mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O, heat in a water bath to obtain the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent, and freeze-dry it into powder for storage in a vacuum.

2. The method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent according to claim 1, characterized in that: In step 1), the mass volume ratio of CTAB, NaOL, water, HAuCl4, AgNO3, hydroquinone and gold seed solution is 1.8-1.85 g: 55-60 mg: 35-40 mL: 0.4-0.6 mL: 2-2.5 mL: 8-12 mL: 50-300 μL.

3. The method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent according to claim 1, characterized in that: In step 1), the reaction is specifically as follows: stirring for 30 seconds, and then standing at 25° C. to react overnight.

4. The method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent according to claim 1, characterized in that: In step 2), before adding the mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O, the solution needs to be heated to 65°C.

5. The method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent according to claim 1, characterized in that: In step 2), the mass concentration of Mg(NO3)2·6H2O in the mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O is 10-11 mg / mL, and the mass concentration of Al(NO3)3·9H2O is 7-8 mg / mL.

6. The method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent according to claim 1, characterized in that: In step 2), the volume ratio of the NaOH / NaCO3 buffer, the AuNBPs dispersion and the mixed solution of Mg(NO3)2·6H2O and Al(NO3)3·9H2O is 40mL:5mL:5mL.

7. The method for preparing a gold nanobipyramid / magnesium aluminum hydrotalcite composite nano diagnostic and therapeutic agent according to claim 1, characterized in that: The water bath heating is specifically as follows: the temperature of the water bath is maintained at 65° C., and the stirring and heating are continued for 6 hours.

8. A gold nanobipyramid / magnesium aluminum hydrotalcite composite nanodiagnostic agent prepared by the method for preparing the gold nanobipyramid / magnesium aluminum hydrotalcite composite nanodiagnostic agent as described in any one of claims 1 to 7.

9. Use of the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent as claimed in claim 8 in photothermal therapy.

10. Use of the gold nanobipyramid / magnesium aluminum hydrotalcite composite nano-diagnostic agent as claimed in claim 8 in biological imaging.

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