Photo-thermal tumor immune activator as well as preparation method and use method thereof

Abstract

The invention belongs to the field of medicines, and particularly relates to application of an advanced material in a tumor immune activator. The invention provides a biodegradable light-triggered immune activator based on an M-MoS2 (at) siRNA compound. The biodegradable light-triggered immune activator comprises a lamellar-structure metal phase MoS2 substrate with photo-thermal response performance, an M-MoS2 (at) siRNA compound and a light-triggered siRNA compound, a siRNA drug capable of reversing a tumor immune microenvironment; the siRNA drug is assembled on the surface of the metal phase MoS2 substrate through non-covalent interaction. The invention also provides a preparation method of the photo-thermal tumor immune activator and a use method of the photo-thermal tumor immune activator in tumor treatment drugs. The product is good in photo-thermal performance, excellent in biodegradability and simple and efficient in assembly mode, siRNA medicine and M-MoS2 photo-thermal response cooperate, the tumor immunosuppression microenvironment can be reversed while tumor cells are killed through a photo-thermal therapy, differentiation and infiltration of T cells are greatly promoted, a strong anti-cancer immune response is generated, and the anti-cancer effect is achieved. And efficient inhibition of in-situ tumors and far-end tumors is realized.

Description

Technical Field

[0001] The present invention belongs to the field of medicine, and specifically relates to the application of advanced materials in tumor immune activators. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Cancer immunotherapy, which activates the patient's immune system to eliminate primary and metastatic tumors, has achieved significant success in the clinical treatment of cancer. Despite its promising prospects, cancer immunotherapy still faces numerous challenges. Systemic administration of immunotherapeutic agents (such as immune checkpoint blockers, cytokines, or adjuvants) often results in their distribution into normal tissues, leading to limited therapeutic efficacy and potential immune-related adverse events. Furthermore, tumor cells can induce changes in the tumor microenvironment (TME) by overexpressing immune checkpoint proteins, which can lead to immunotherapy failure. Inhibiting TME-reactive immune checkpoints, termed immune checkpoint blockade (ICB), is considered an attractive therapeutic strategy to reduce immunosuppressive effects in the TME. However, although ICB has demonstrated promising effects in enhancing anti-tumor T cell immunity in certain cancers, current clinical treatments for ICB primarily employ antibodies, and their clinical effectiveness is limited to specific tumor types and a small subset of patients. Therefore, there is an urgent need to identify alternative approaches to activate cancer immunotherapy.

[0004] Photothermal immunotherapy (PTI) combines non-invasive photothermal therapy (PTT) with immunotherapy and has gradually attracted attention in recent years. Non-invasive photothermal therapy (PTT) can not only eliminate tumor cells, but also induce immunogenic cell death (ICD) in tumor tissues, thereby promoting the differentiation and infiltration of tumor-specific T cells and generating a strong anti-cancer immune response. However, many photo-tumor immune activators currently under research have the following shortcomings: (1) complex preparation process; (2) poor biodegradability; (3) low biosafety; (4) single functionality. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides a light-triggered immune activator based on a metallic phase MoS2@siRNA complex. The M-MoS2 has a 2D layered structure on which gene drugs are loaded, hence the name "2D gene nanosheet" or "Genesheet," comprising the following structure: A metallic phase MoS2 substrate, wherein the metallic phase MoS2 substrate has a lamellar structure and has photothermal response performance; siRNA drugs, which are designed and synthesized based on immune checkpoint protein mRNA and can act on the tumor immune microenvironment to block immune checkpoints; The siRNA drug is spontaneously assembled on the sheet surface of the metallic phase MoS2 substrate through non-covalent interactions.

[0006] Molybdenum disulfide (MoS2) is a representative class of 2D transition metal sulfides (TMDCs). Its main component is a series of vertically stacked multilayer structures less than 10 nm thick, bonded by van der Waals forces. Mo in MoS2 is an essential trace element for the human body, while S is a major element required for daily life. The present invention utilizes a 1T crystal-form metallic phase of MoS2. Its lamellar structure provides photothermal responsiveness, enabling photothermal conversion under laser irradiation. Furthermore, its lamellar structure enables spontaneous supramolecular self-assembly with siRNA drugs, forming a stable non-covalent bond.

[0007] Preferably, the metallic phase MoS2 substrate has an ultrathin lamellar structure with a thickness of less than 5 nm. A metallic phase MoS2 substrate with a thickness of less than 5 nm has an ultrathin lamellar structure that is nearly 2D and has a good crystal structure, resulting in better photothermal performance and better colloidal stability.

[0008] Preferably, the metallic phase MoS2 substrate responds to NIR-II (second near infrared light).

[0009] Second near-infrared (NIR-II) (1000-1350 nm range) photoimmunoactivators offer advantages in deep tissue penetration, high permissible energy, excellent sensitivity, and signal-to-noise ratio. MoS2, a 1T metallic phase, exhibits strong absorption and photothermal conversion efficiency in the NIR-II region.

[0010] Preferably, the immune checkpoint protein blocked by the siRNA drug is one or more of PD1, PDL1, CTLA4, LAG3, TIM3, TIGHT, IDO1 or TDO.

[0011] Common tumor immune checkpoint proteins include PD1 / PDL1 (programmed cell death protein PD1 and programmed death ligand PD-L1), CTLA4 (cytotoxic T lymphocyte-associated antigen 4), LMTK3 (Lemur tyrosine kinase 3), LAG3 (lymphocyte activation gene 3, LAG-3 / CD223), TIM3 (T lymphocyte immunoglobulin mucin 3), TIGHT (T cell immunoglobulin and ITIM domain), IDO1 (indoleamine 2,3-dioxygenase 1), and TDO (tryptophan 2,3-dioxygenase). The pathways involved in these proteins generate inhibitory signals in T cells and negatively regulate T cell immune function. Therefore, the siRNA drug of the present invention, after targeting the corresponding mRNA, can specifically downregulate the synthesis of subsequent proteins, attenuating the immune suppression mediated by these proteins and achieving immune checkpoint blockade.

[0012] Particularly preferably, the nucleic acid sequence of the siRNA is: GCAAUAUUGCUGUUCCCUATT (5'-3'), which can downregulate the expression of indoleamine 2,3-dioxygenase 1 (IDO1) protein and reverse IDO1-mediated immunosuppression.

[0013] Preferably, the spontaneous assembly of the siRNA drug with the metallic phase MoS2 substrate adopts one or more of PS, hydrogen bonding or non-covalent interactions between charges.

[0014] The present invention also provides a preparation method of a photothermal tumor immune activator, comprising the following steps: Step 1: using MoO3, thioacetamide and urea as raw materials, a metal phase MoS2 substrate is synthesized by a hydrothermal method; Step 2: siRNA drugs are designed and synthesized based on the immune checkpoint protein mRNA, and the siRNA drugs can act on the tumor immune microenvironment to block the immune checkpoints; Step 3: the siRNA drug and the metal phase MoS2 substrate are mixed in a mass ratio of 1:3, stirred at room temperature and then centrifuged to obtain the photothermal tumor immune activator.

[0015] Preferably, the specific steps of synthesizing the metallic phase MoS2 substrate by the hydrothermal method are as follows: dissolving MoO3, thioacetamide and urea in deionized water, stirring and pouring into an autoclave, reacting at 180-250 ° C for 8h to 12h, and cooling the solution to room temperature; filtering through a filter membrane, washing with deionized water and then dispersing in deionized water for ultrasonic treatment; finally freeze-drying to obtain a black solid product.

[0016] The present invention also provides a method for using the photothermal tumor immunity activator: the photothermal tumor immunity activator is used in the preparation of a drug or a kit for tumor immunotherapy.

[0017] Preferably, NIR-II (second near infrared light) treatment is used, and the tumor tissue used is a primary tumor and / or a distal tumor.

[0018] The present invention uses the biocompatible and degradable metallic phase MoS2 as the substrate. Through a simple and efficient supramolecular self-assembly strategy, the siRNA drug that can reverse the immunosuppressive microenvironment is modified on the surface of the layered M-MoS2. This new tumor immune activator is evenly dispersed in water, has good colloidal stability, good photothermal performance, and can be biodegraded in tumor sites with high H2O2 concentrations.

[0019] The photothermal tumor immune activator (M-MoS2@siRNA) described in this invention features nanoparticles of optimal size, enabling passive targeted entry into tumors through the permeability-enhancing retention (EPR) effect, enabling efficient delivery and accumulation of both the siRNA and M-MoS2 at the tumor site. Furthermore, the photothermal response of the siRNA and M-MoS2 enables synergistic effects in tumor immunotherapy: the siRNA activates immune checkpoint blockade (ICB) and reverses the tumor's immunosuppressive microenvironment; while the M-MoS2 responds to laser irradiation with efficient heat generation, promoting immunogenic cell death (ICD) and promoting rapid T cell differentiation and infiltration at the tumor site. These two synergistic effects generate a powerful anti-cancer immune response, effectively suppressing both in situ and distant tumors. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 Absorption spectra of 2D gene nanosheets. Sample 1 is an aqueous M-MoS2 dispersion, and sample 2 is an aqueous 2D gene nanosheet dispersion. In the figure, the black line represents M-MoS2, and the red line represents the 2D gene nanosheet.

[0022] Figure 2 : HRTEM image and element distribution of 2D gene nanosheets.

[0023] Figure 3 : Degradation performance of 2D gene nanosheets.

[0024] Figure 4 : Tumor cell endocytosis and siRNA delivery performance of 2D gene nanosheets, where Figure (a) is flow cytometry analysis and Figure (b) is cell endocytosis fluorescence imaging.

[0025] Figure 5In vivo tumor enrichment and photothermal imaging performance of 2D gene nanosheets. Figure (a) shows photothermal imaging of a mouse; Figure (b) shows temperature statistics at the tumor site.

[0026] Figure 6 : 2D gene nanosheet tumor treatment effect diagram. Among them, (a) is the primary tumor weight, (b) is the primary tumor inhibition rate, (c) is the primary tumor treatment image, (d) is the distal tumor weight, (e) is the distal tumor inhibition rate, and (f) is the distal tumor image; G1: PBS, G2: M-MoS2, G3: M-MoS2@scr, G4: 2D gene nanosheet (G represents group). Primary tumors were irradiated with (+) or not (-) laser (1.0 W·cm -2 , 1064 nm).

[0027] Figure 7 : Flow cytometric results of T cell differentiation after laser irradiation of 2D gene nanosheets. (a) Flow cytometric analysis demonstrated CD8+ and CD4+ in primary and distant tumors of 4T1 tumor-bearing mice after different treatments. (b) Flow cytometric analysis of CD80+ / CD86+ double-positive DCs in the inguinal lymph nodes of 4T1 tumor-bearing mice after different treatments. In all experiments, 4T1 tumor-bearing mice were intravenously injected with G1: PBS, G2: M-MoS2, G3: M-MoS2@scr, G4: 2D gene sheet (M-MoS2: 7.5 mg kg -1 ) (G represents group), and the primary tumors were irradiated with (+) or not (-) NIR light (1.0 W·cm -2 , 1064 nm). DETAILED DESCRIPTION

[0028] The following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The following examples are intended only to explain the present invention and are not intended to limit its contents. If the specific experimental conditions are not specified in the examples, they are generally in accordance with conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0029] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

[0030] Example 1: Preparation of 2D metallic phase MoS2 (M-MoS2) sheets Dissolve 120 mg of MoO₃, 140 mg of thioacetamide, and 1.2 g of urea in 100 mL of deionized water and stir for 2 hours. Pour the solution into an autoclave, then place it in an oven and react at 200°C for 10 hours. Then, slowly cool the solution to room temperature. Filter the solution through a 200 μm pore size filter membrane. Wash the filter cake five times with deionized water. Redisperse the resulting filter cake in deionized water and sonicate for 10 minutes. After lyophilization, 80 mg of the product, a black solid, is obtained.

[0031] Example 2: Preparation of 2D gene nanosheets (M-MoS2@siRNA): In this embodiment, siRNA is used to target the mRNA of the immune checkpoint protein IDO1. The nucleic acid sequence of the siRNA is: (5'-3') GCAAUAUUGCUGUUCCCUATT, and it is prepared by solid phase synthesis technology.

[0032] 333 μg of the aforementioned siRNA was dissolved in DEPC-treated water and added to 1 mL of M-MoS2 (1 mg / mL). The mixture was stirred at room temperature for 1 hour and centrifuged at 13,000 rpm to remove free siRNA. The siRNA drug assembled onto the surface of the layered MoS2 through non-covalent interactions such as PS, hydrogen bonding, and charge interactions, achieving supramolecular self-assembly, resulting in a "2D gene nanosheet" nanodrug, the aforementioned "photothermal tumor immunity activator."

[0033] Of course, those skilled in the art can use any existing technology to design corresponding siRNA drug sequences based on other mRNAs targeting immune checkpoint proteins. As long as they can achieve immune checkpoint blockade in the tumor site to a certain extent, they can reproduce the technical solution expected to be achieved by the present invention without creativity.

[0034] Experiments to test the properties or performance of 2D gene nanosheets: (1) Water dispersibility and colloid stability The free siRNA in the supernatant of the product of Example 2 was detected by Nanodrop, and the UV absorption spectrum of the M-MoS2 aqueous dispersion was compared. Figure 1 As shown in Figure 2, the 2D gene nanosheets obtained in this example have a narrow hydrated particle size and exhibit good water dispersibility and colloidal stability. The 2D gene nanosheet aqueous dispersion exhibits similar absorption and dispersion properties to the M-MoS2 aqueous dispersion.

[0035] (2) Microscopic crystal structure and element distribution results: The HRTEM results of the 2D gene nanosheets prepared in Example 2 showed that they had an ultra-thin layer structure and good crystal form (see Appendix Figure 2 ).

[0036] Attachment Figure 2 Figure (a) shows that the M-MoS2 sheet material is almost a single-layer material, and the HRTEM results show the lattice and wrinkles of the material; Figure (b) is its element distribution diagram, in which the element distribution of carbon, oxygen, nitrogen, and phosphorus is roughly consistent with the molybdenum distribution area, which shows that the siRNA drug in Example 2 has been adsorbed on M-MoS2.

[0037] (3) Biodegradation performance of 2D gene sheets: 100 μg mL -1 The 2D gene nanosheets were stored at room temperature with different concentrations of H2O2 (0, 0.1, 1, 5, 10 mM) for 14 days, and images of them at different time points (1 h, 3 h, 1 day, 3 days) were taken with a digital camera. The results are shown in the attached figure. Figure 3 As shown in Figure 2, the degradation rate of the 2D gene nanosheets accelerated with increasing H2O2 concentration. The degradation process reached a steady state in approximately 3 hours, and the degree of degradation did not change significantly with increasing storage time.

[0038] Because H2O2 is rich in the tumor microenvironment and tumor cells, this experiment also shows that the 2D gene nanosheets obtained in Example 2 have good biodegradability at the tumor site.

[0039] Example 3: Application of 2D gene nanosheets in tumor immunotherapy (1) siRNA delivery and endocytosis performance of 2D gene nanosheets 4T1 cells were cultured at 5 × 10 4 Cells were seeded at a density of 500 μg / well in confocal culture dishes overnight and treated with Cy5-labeled siRNA to create 2D gene nanosheets for 12 hours. The cells were then washed three times with PBS and stained with Hoechst 33342 for 5 minutes. The cells were then washed three times with PBS and imaged using a confocal microscope (Leica TCSSP8).

[0040] The results are as follows Figure 4 As shown in the figure, the results show that the 2D gene nanosheet was successfully internalized by the target cells, and its fluorescence was localized in the cytoplasm of the target cells, proving that the 2D gene nanosheet has good siRNA delivery and cellular endocytosis performance. Cell flow cytometry also verified this result.

[0041] (2) Tumor enrichment and in situ photothermal performance of 2D gene nanosheets 4T1 tumor-bearing mice were intravenously injected with PBS, M-MoS2, and 2D gene nanosheets, respectively. The tumor was irradiated with 1064nm laser (3min). Thermal images of the mice were captured using a thermal imager, and the tumor temperature was recorded.

[0042] The results are as attached Figure 5 As shown in the figure, the temperature of tumor cells in the PBS control group also showed an upward trend under 1064 nm laser irradiation, reaching 37.5°C after 3 minutes; the temperature in the M-MoS2 group reached 40.5°C after 3 minutes of laser treatment. In contrast, the 2D gene nanosheet prepared in Example 2 of the present invention ("Genesheet Group") reached 43.2°C after 3 minutes of treatment, demonstrating a superior photothermal effect to the previous two groups.

[0043] Experiments have shown that the 2D gene nanosheets in this experiment can be effectively enriched in the tumor site, producing a strong photothermal effect under the irradiation of a 1064 nm laser, rapidly increasing the temperature of the tumor site in a short period of time; at the same time, as the irradiation time increases, the temperature of the tumor site continues to rise. Due to the effect of siRNA immune checkpoint blocking, the genesheet group can reach a temperature upper limit significantly exceeding that of the M-MoS2 group.

[0044] Generally speaking, when the temperature of tumor tissue rises, cells die and release antigens and cell fragments, activating an immune response. As the temperature rises, the number of cells that die increases and the rate of cell death increases, leading to a stronger immune response. The 2D gene nanosheets of this invention can quickly reach a temperature limit of 43.2°C, effectively triggering an immune response.

[0045] Those skilled in the art will appreciate that M-MoS2 can generate photothermal heat within the second near-infrared (1000-1350 nm) and even a wider range of near-infrared light, achieving a warming effect at the tumor site. The experimental results, using 1064 nm laser irradiation, represent the preferred embodiment.

[0046] (3) Tumor treatment effect of 2D gene nanosheets BALB / c mice bearing 4T1 tumors were randomly divided into 8 groups. When the primary tumor volume reached approximately 150 mm 3 At 0, 5, and 10 days, mice were intravenously injected with 200 μL PBS, M-MoS2, M-MoS2@scr, and M-MoS2@siRNA (i.e., 2D gene nanosheets) and designated as G1 to G4 groups. For G2-G4 groups, 6 h after each injection, laser (1 W·cm -2 , 1064 nm) irradiated the primary tumor of each mouse for 8 min.

[0047] The sizes of primary and distant tumors, as well as the weight of the mice, were then measured every two days for 15 consecutive days. After 15 days of treatment, mice in each group were dissected, cleaned, wiped, weighed, and photographed. The collected tumor inhibition rate (TIR) ​​was calculated based on tumor weight.

[0048] The results are as attached Figure 6 As shown. M-MoS2 treatment had almost no inhibitory effect on tumors when not exposed to light. However, 1064 nm laser irradiation exhibited a certain tumor-suppressing effect due to a certain photothermal therapeutic effect (see comparison of G2-G3 (-) and (+) groups). In contrast, M-MoS2@siRNA, when not exposed to light, achieved a certain degree of tumor suppression in the G4 (-) group due to immune checkpoint blockade by siRNA. However, after 1064 nm laser irradiation, the G4 (+) group demonstrated that the 2D gene nanosheets significantly inhibited the growth of both in situ and distal tumors, demonstrating excellent therapeutic efficacy (see Figures b and c).

[0049] (4) 2D gene nanosheets promote T cell differentiation and activate tumor immune response In this experiment, flow cytometry was used to detect the differentiation of T cells in mice treated with different groups, in order to verify the synergistic effect of siRNA and M-MoS2 in tumor immunotherapy.

[0050] After culturing tumor-bearing mice in groups G1 to G4 under different treatments for 15 days, the mice in each group were euthanized, and the primary tumors and distant tumors were collected and treated with 1 mg mL -1 Collagenase type I, 100 μg mL -1 Type IV collagenase and 100 μg mL -1 After digestion with DNase I at 37°C for 2 hours, the tissue was filtered through a 70 μm cell strainer. The resulting tumor single-cell suspension was then depleted of erythrocytes using the ACK lysis method, and the cells were washed with cell staining buffer. The cells were then incubated with anti-CD16 antibody for 10 minutes. For cell surface antigen staining, the cells were stained with anti-CD45, anti-CD3, anti-CD4, anti-CD8a, anti-Gr-1, and anti-CD11b antibodies for 30 minutes. After washing with cell staining buffer, the cells were analyzed using a Fortessa X20 (BD Biosciences).

[0051] The results can be found in Figure 7Compared to the other groups, the CD8+ T cell density in the G4(-) group, even without light exposure, accounted for more than 40% of the figure, a significantly higher proportion than in the other groups. This suggests that siRNA drug treatment in the G4 group was able to deliver to the tumor site and target the tumor immune microenvironment (TME), reducing the immunosuppressive effects of the TME and promoting T cell differentiation.

[0052] After laser irradiation, the M-MoS2 in groups G2-G4 produced a photothermal response, with increases in the density of CD8+ and CD4+ T lymphocytes in each group. In particular, the 2D gene nanosheet (M-MoS2@siRNA) in group G4(+) generated a high photothermal temperature, which not only killed tumor cells but also significantly promoted the rapid differentiation of CD8+ T cells. Figure 7 The CD8+T cell ratio in the G4(+) group reached about 60%, which greatly exceeded the ratio of this type of T cells in other groups. The rapid differentiation and increase in the ratio of CD8+T cells in the G4(+) group can significantly enhance the tumor immune response and achieve the G4(+) group in the attached Figure 6 The tumor suppressive effect shown.

[0053] In summary, the M-MoS2@siRNA protected by this invention can be enriched in tumor sites after near-infrared light treatment and produce a photothermal response, promoting the rapid differentiation of T cells within tumor tissue and significantly increasing their proportion. Simultaneously, siRNA suppresses the tumor's TME, allowing T cells to fully exert their immunotherapy effects. The two work synergistically, resulting in a significant tumor immunotherapy effect.

[0054] Although the technical solutions of the present invention have been described and listed in detail, it should be understood that it is obvious to those skilled in the art to make modifications to the above embodiments or adopt equivalent alternatives. These modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A photothermal tumor immune activator, It is characterized in that have: Metallic phase MoS 2 substrate, the metallic phase MoS 2 The substrate has a lamellar structure and has photothermal response performance; siRNA drugs, which are designed and synthesized based on immune checkpoint protein mRNA and can act on the tumor immune microenvironment to block immune checkpoints; The siRNA drug spontaneously assembles in the metallic phase MoS through non-covalent interactions. 2 The lamellar surface of the base.

2. A photothermal tumor immune activator as claimed in claim 1, Features: The metallic phase MoS 2 The substrate is an ultra-thin layer structure with a thickness of less than 5 nm.

3. A photothermal tumor immune activator as claimed in claim 2, Features: The metallic phase MoS 2 The substrate responds to the second near infrared light.

4. A photothermal tumor immune activator according to claim 1, Features: The immune checkpoint protein blocked by the siRNA drug is one or more of PD1, PDL1, CTLA4, LAG3, TIM3, TIGHT, IDO1 or TDO.

5. A photothermal tumor immune activator as claimed in claim 4, Features: The nucleic acid sequence of the siRNA is: (5'-3') GCAAUAUUGCUGUUCCCUATT, which can downregulate the expression of indoleamine 2,3-dioxygenase 1 (IDO1) protein and reverse IDO1-mediated immunosuppression.

6. A photothermal tumor immune activator as claimed in claim 1, Features: The siRNA drug and the metal phase MoS 2 The spontaneous assembly of the substrate employs one or more of PS, hydrogen bonding, or non-covalent interactions between charges.

7. A method for preparing a photothermal tumor immune activator, It is characterized in that The following steps are involved: Step 1: MoO 3 , thioacetamide and urea as raw materials, and the metallic phase MoS was synthesized by hydrothermal method. 2 substrate; Step 2: Designing and synthesizing siRNA drugs based on immune checkpoint protein mRNA, wherein the siRNA drugs can act on the tumor immune microenvironment to block the immune checkpoints; Step 3: The siRNA drug is mixed with the metal phase MoS 2 The bases were mixed at a mass ratio of 1:3, stirred at room temperature and then centrifuged to obtain the photothermal tumor immune activator.

8. The preparation method according to claim 7, It is characterized in that The hydrothermal method synthesizes metallic phase MoS 2 The specific steps of the substrate are as follows: MoO 3 , thioacetamide and urea are dissolved in deionized water, stirred and poured into an autoclave, reacted at 180-250 °C for 8 to 12 hours, and the solution is cooled to room temperature; filtered through a filter membrane, washed with deionized water for multiple times, and then dispersed in deionized water for ultrasonic treatment; finally freeze-dried to obtain a black solid product.

9. Use of the photothermal tumor immune activator as claimed in claim 1, Features: The photothermal tumor immunity activator is used for preparing tumor immunotherapy drugs.

10. The use according to claim 9, Features: When used, the second near-infrared light treatment is adopted, and the applied tumor tissue is the primary tumor and / or the distal tumor.

Images