Multimodal diagnosis and treatment nanoparticles excited by near-infrared region 2 and preparation method and application thereof

Abstract

The application discloses a kind of near-infrared two-zone excited multimodal diagnosis and treatment nanoparticles and preparation method, application.The multimodal diagnosis and treatment nanoparticles include: the core formed by iridium complex and amphiphilic polymer wrapped in the surface of the core.The multimodal diagnosis and treatment nanoparticles prepared by the application can generate reactive oxygen species in anoxic environment by using singlet oxygen carrier to load singlet oxygen, which overcomes the oxygen-dependent two-type photodynamic therapy.The nanoparticles can generate hydrogen to realize hydrogen therapy, because iridium complex with adaptive electron structure can catalyze water to generate hydrogen.In addition, hydrogen has anti-inflammatory effect and can alleviate the negative effects generated in the process of phototherapy.Light and photodynamic therapy combined with gas therapy realize multifunctional treatment system to reduce the treatment efficiency of single treatment mode.Nanoparticles can quickly enrich in tumor site and realize near-infrared two-zone fluorescence / photoacoustic / photoacoustic imaging navigation.

Description

Technical Field

[0001] This invention relates to the field of biomedical nanomaterials technology, specifically to a near-infrared II excited multimodal diagnostic and therapeutic nanoparticle, its preparation method, and its applications. Background Technology

[0002] Photodynamic therapy (PDT), as an emerging cancer treatment method distinct from traditional approaches, possesses immense potential for development in tumor treatment due to its advantages such as high spatiotemporal selectivity, minimal invasiveness, and low toxicity. Despite its numerous advantages, PDT still faces several challenges that need to be addressed. For example, the hypoxic environment within the tumor, the lack of targeted photosensitizers, and limited treatment depth significantly reduce the effectiveness of PDT.

[0003] Therefore, existing technologies still need further improvement and development. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the issue that existing near-infrared II excitation-aggregation-induced emission molecules have poor photodynamic therapy efficacy in hypoxic environments. The invention aims to provide an infrared II excitation-aggregation-induced emission material that can meet the needs of tumor treatment in hypoxic environments.

[0005] The technical solution adopted by this invention to solve this technical problem is as follows: Near-infrared excited AIE photothermal molecules with Type I and Type II photochemical reaction processes are used in combination with a thermocontrolled release singlet oxygen reagent. First, singlet oxygen is loaded onto a singlet oxygen carrier in vitro. Then, the reagent reaches the tumor through the EPR effect and releases singlet oxygen under thermal stimulation. This process does not require the participation of oxygen, thus realizing near-infrared II imaging and photodynamic therapy in an anaerobic environment.

[0006] Firstly, the near-infrared II excited multimodal therapeutic nanoparticles include: a core formed by an iridium complex and an amphiphilic polymer coated on the surface of the core; the structural formula of the iridium complex is:

[0007] The structural formula of the amphiphilic polymer is:

[0008] Where n = 60.

[0009] Secondly, a method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region as described in the first aspect, wherein the method includes: Compound DPTP and Ir(ppy)4Cl2 (ppy = 2-phenylpyridine) were heated under nitrogen atmosphere and stirred under reflux for 4 h. After the reaction was completed, the mixture was cooled to room temperature and purified by silica gel column chromatography to obtain the iridium complex IrDPTP. 3-Methyl-2-pyridone and p-nitrobenzyl bromide were added to potassium carbonate, potassium iodide, 18-crown ether and acetone under nitrogen protection and stirred at room temperature for 24 h. After the reaction was completed, the mixture was extracted and dried under evaporation, and then purified by silica gel column chromatography to obtain compound A. Compound A, ammonium formate, palladium on carbon, and methanol were reacted overnight at room temperature with stirring. After the reaction was complete, the mixture was extracted and evaporated to dryness, then purified by column chromatography to obtain compound B. Compound B and polymaleic anhydride were reacted with tetrahydrofuran under a nitrogen atmosphere. The reaction mixture was refluxed overnight. After the reaction was completed, the polymer P-MePYR was obtained by precipitation. Polymer P-MePYR, 1-(3-dimethylpropyl)-3-ethylcarbodimethylamine hydrochloride, N-hydroxysuccinimide, and ultra-dry N,N-dimethylformamide were stirred at room temperature for 0.5 h under a nitrogen atmosphere. Then, amino polyethylene glycol 2000 was added, and the mixture was stirred at room temperature for 2 days. After the reaction was complete, the solvent was removed, and the product was dissolved in ultrapure water and dialyzed for three days using a dialysis bag (e.g., Mw: 8000-14000). Finally, the product PPEG-MePYR was obtained by freeze drying. The polymer PPEG-MePYR was dissolved in N,N-dimethylformamide solution, and an excess of methylene blue was added. The mixture was stirred at 0 °C until homogeneous, and then irradiated with a 660 nm laser for 4 h. After that, it was dialyzed at 0 °C for three days using a dialysis bag (Mw: 8000-14000). Finally, it was freeze-dried to obtain the polymer PPEG-MeRPO. The polymer PPEG-MeEPO was dissolved in ultrapure water and sonicated for 5 min, then cooled in an ice-water mixture. The iridium complex was dissolved in tetrahydrofuran and then quickly added to the polymer aqueous solution and sonicated for 3 min. The solution was then dialyzed at 0 °C for three days. After the dialyzed solution was dissolved in an ultrafiltration centrifuge tube with a molecular weight of 100 kDa, the nanomaterial Ir@PPEG-MeEPO was obtained.

[0010] Thirdly, the application of a type of near-infrared II excited multimodal diagnostic and therapeutic nanoparticle as described above in the preparation of a photothermal synergistic immunodiagnostic and therapeutic integrated reagent.

[0011] Beneficial Effects: Compared with existing technologies, the multimodal therapeutic nanoparticles prepared in this invention utilize singlet oxygen carriers to load singlet oxygen, enabling the generation of reactive oxygen species in hypoxic environments and overcoming oxygen-dependent type II photodynamic therapy. These multimodal therapeutic nanoparticles, due to their iridium complexes with adapted electronic structures, can catalyze the production of hydrogen from water, thus enabling hydrogen therapy. Furthermore, hydrogen has anti-inflammatory properties, mitigating the negative effects of phototherapy. The combination of photothermal and photodynamic therapy with gas therapy achieves a multifunctional treatment system, reducing the treatment efficiency of single-modality treatments. The multimodal therapeutic nanoparticles can rapidly accumulate at tumor sites and achieve near-infrared II fluorescence / photoacoustic / photothermal imaging navigation. Attached Figure Description

[0012] Figure 1 1H NMR spectrum of PPEG-MePYR prepared in Example 1; Figure 2 SEM image of Ir@PPEG-MeEPO prepared in Example 1; Figure 3 The UV-Vis absorption and emission spectra of Ir@PPEG-MeEPO prepared in Example 1 (a) and the fluorescence emission spectrum of IrDPTP prepared in a tetrahydrofuran / n-hexane mixed solvent (b). Figure 4 In Example 2, (a) is a graph showing the temperature change of Ir@PPEG-MeEPO (100 μg / mL) over time under different laser powers in the photothermal test, and (b) is a graph showing the temperature change of Ir@PPEG-MeEPO at different concentrations over time under a laser power of 0.3 mW. Figure 5 The in vitro photodynamic test results of Ir@PPEG-MeEPO prepared in Example 1 include: a comparison of ROS generation after Ir@PPEG-MeEPO was blended with DCFH and heated to 50°C in the dark. Figure 6 A comparison of ROS generated after light irradiation of Ir@PPEG-MeEPO prepared in Example 1 and DCFH. Figure 7 A comparison chart of hydrogen release from the iridium complex prepared in Example 1 under different light exposure times; Figure 8 In Example 4, the survival rate of 4T1 cells containing different concentrations of Ir@PPEG-MeEPO under light or dark conditions is shown in the bar graphs: (a) normoxic conditions, (b) hypoxic conditions. Figure 9 Example 5 shows fluorescent images of reactive oxygen species generated in cells by Ir@PPEG-MeEPO under different conditions; Figure 10 In Example 6, the imaging images of Ir@PPEG-MeEPO at the tumor site in tumor-bearing mice include: (a) a graph showing the change of near-infrared II fluorescence imaging over time; (b) a graph showing the change of photoacoustic imaging over time; and (c) a graph showing the temperature change of the tumor site within 10 minutes after Ir@PPEG-MeEPO was injected into the tumor-bearing mouse via the tail vein and then irradiated with a 660 nm laser for 1 h. Figure 11 In Example 7, the tumor inhibition curves of different drugs on 4T1 tumor-bearing mice (a) and the imaging image of the ex vivo tumor after treatment (b) are shown. Detailed Implementation

[0013] The near-infrared II excited multimodal therapeutic nanoparticles provided by this invention are further described in detail below to make the objectives, technical solutions, and advantages of this invention clearer and more explicit. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0014] Example 1 Step 1. Synthesize iridium complexes in the near-infrared II region. The synthetic route is as follows:

[0015] Compound DPTP and Ir(ppy)4Cl2 (ppy = 2-phenylpyridine) were reacted under a nitrogen atmosphere with a mixed solution of dichloromethane and methanol, and the mixture was refluxed and stirred for 4 h. After the reaction was complete, the mixture was cooled to room temperature. Excess potassium hexafluorophosphate was added to the mixed solution and stirred for 0.5 h. The mixture was then filtered and evaporated to dryness, and purified by silica gel column chromatography to obtain the iridium complex IrDPTP. The NMR and mass spectrometry characterization data of the product are as follows: 1 H NMR (600 MHz, CDCl3, 298 K) δ (ppm): 9.16 (d, J = 7.2 Hz, 1H), 8.25 (d, J = 3.6 Hz, 1H), 7.98–7.91 (m, 4H), 7.74–7.24 (m, 2H), 7.63–7.62 (m,1H), 7.37 (d, J = 7.8 Hz, 2H), 7.19–7.08 (m, 8H), 7.00–6.96 (m, 4H), 6.77 (d, J = 8.4 Hz, 2H), 6.65 (d, J = 8.4 Hz, 2H), 6.41 (d, J= 7.2 Hz, 1H), 3.78–3.69(m, 4H), 1.70–1.65 (m, 6H), 1.33–1.21 (m, 12H), 0.93–0.83 (m, 9H), 0.77–0.71(m, 3H). 13 C NMR (126 MHz, CD3CN, 298 K) δ (ppm): 168.30, 159.18, 159.17,159.15, 153.54, 153.46, 153.38, 151.38, 150.69, 149.74, 146.09, 146.05,145.51, 145.09, 142.28, 140.79, 139.52, 137.22, 137.02, 136.03, 133.85,133.83, 133.43, 133.36, 132.83, 132.63, 132.23, 131.63, 131.54, 128.90,127.46, 126.15, 124.10, 121.04, 120.95, 118.26, 114.87, 114.76, 114.70,114.58, 71.72, 71.24, 40.20, 40.10, 31.15, 29.72, 24.52, 23.71, 14.38, 14.33,11.66, 11.50, 11.42, 11.38. MS ( m / z ): [M] + calcd. for C 124 H 126 IrN8O4S,2014.91089; found, 2015 (MALDI-TOF MS); 2014.91089 (ESI-HRMS). Step 2. Synthesize the amphiphilic polymer containing a singlet oxygen support. The synthetic route is as follows:

[0016] 3-Methyl-2-pyridone and p-nitrobenzyl bromide were added to potassium carbonate, potassium iodide, 18-crown ether, and acetone under nitrogen protection and stirred at room temperature for 24 h. After the reaction was complete, the mixture was extracted and evaporated to dryness, and then purified by silica gel column chromatography to give compound 1. The NMR data of the product are as follows: 1 H NMR (500 MHz, CDCl3, 298 K) δ (ppm): 8.16 (d, J= 8.5 Hz, 2H), 7.43 (d, J = 8.5 Hz, 2H), 7.24–7.17 (m, 2H), 6.14 (t, J = 6.5 Hz, 1H), 5.20 (s, 2H), 2.15 (s, 3H). Compound 1, ammonium formate, palladium on carbon, and methanol were reacted overnight at room temperature with stirring. After the reaction was complete, the mixture was extracted and evaporated to dryness, then purified by column chromatography to obtain compound 2. The NMR data of the product are as follows: 1 H NMR (500 MHz, DMSO- d 6,298 K) δ (ppm): 7.54 (dd, J = 6.5, 1 Hz, 1H), 7.25 (ddd, J = 6.5, 2, 1.0 Hz, 1H), 7.01(d, J = 8 Hz, 2H), 6.51–6.47 (m, 2H), 6.10 (t, J = 6.5 Hz, 1H), 5.05 (s, 2H), 4.88 (s, 2H), 1.99 (s, 3H). Compound 2 and polymaleic anhydride were reacted with tetrahydrofuran under a nitrogen atmosphere, and the reaction mixture was refluxed overnight. After the reaction was complete, the polymer P-MePYR was obtained by precipitation. M n: 48477, PDI: 1.14.

[0017] Polymer P-MePYR, 1-(3-dimethylpropyl)-3-ethylcarbodimethylamine hydrochloride, N-hydroxysuccinimide, and ultra-dry N,N-dimethylformamide were stirred at room temperature for 0.5 h under a nitrogen atmosphere. Then, amino-based polyethylene glycol 2000 was added, and the mixture was stirred at room temperature for 2 days. After the reaction was complete, the solvent was removed, and the product was dissolved in ultrapure water and dialyzed for three days using a dialysis bag (Mw: 8000-14000). Finally, the product PPEG-MePYR was obtained by freeze drying. The 1H NMR spectrum of PPEG-MePYR is shown below. Figure 1 As shown.

[0018] The polymer PPEG-MePYR was dissolved in N,N-dimethylformamide solution with excess methylene blue and stirred at 0 °C until homogeneous. Then it was irradiated with a 660 nm laser for 4 h and dialyzed at 0 °C for three days using a dialysis bag (Mw: 8000–14000). Finally, it was freeze-dried to obtain the polymer PPEG-MeRPO.

[0019] The polymer PPEG-MeEPO was dissolved in ultrapure water and sonicated for 5 min, then cooled in an ice-water mixture. The iridium complex was dissolved in tetrahydrofuran and then rapidly added to the polymer aqueous solution and sonicated for 3 min. The solution was then dialyzed at 0 °C for three days. After the dialyzed solution was dissolved in an ultrafiltration centrifuge tube with a molecular weight of 100 kDa, the nanomaterial Ir@PPEG-MeEPO was obtained.

[0020] The morphology of Ir@PPEG-MeEPO prepared in Example 1 was analyzed using transmission electron microscopy (TEM). The TEM results are as follows: Figure 2 As shown, the nanoparticles are approximately 20 nm in size and have a spherical shape. Figure 3 (a) shows the UV absorption and emission spectra of Ir@PPEG-MeEPO in aqueous solution. The maximum absorption peak is 663 nm and the maximum emission peak is 1058 nm. Figure 3 (b) is the fluorescence emission spectrum of Ir@PPEG-MeEPO in a tetrahydrofuran / n-hexane mixed solution. It can be seen from the figure that the iridium complex has the property of aggregation-induced emission.

[0021] Example 2 Photothermal effect of Ir@PPEG-MeEPO in aqueous solution PBS was used as a control group. Temperature changes in aqueous solutions containing nanoparticles were detected using a thermal imager under 660 nm laser irradiation and with lasers of varying power. Figure 4 As shown, the temperature of the aqueous solution containing nanoparticles increases with increasing nanoparticle concentration and laser power.

[0022] Example 3 Evaluation of reactive oxygen species and hydrogen generation in Ir@PPEG-MeEPO aqueous solution 2,7-Dichlorodihydrofluorescein diacetate (DCFH-DA) was used as a reactive oxygen species indicator to detect the generation of reactive oxygen species in aqueous solutions containing nanoparticles. Figure 5 The fluorescence intensity of Ir@PPEG-MeEPO mixed with DCFH (10 μM) was significantly enhanced with prolonged heating time at 50 °C. Figure 6 To compare the fluorescence intensity of Ir@PPEG-MeEPO and Ir@PPEG mixed with DCFH under the same irradiation time in a nitrogen atmosphere, we observed that pure DCFH aqueous solution showed almost no fluorescence. The addition of Ir@PPEG-MeEPO resulted in a very high fluorescence intensity enhancement, while the same concentration of Ir@PPEG showed a lower enhancement to the fluorescence intensity of DCFH. This demonstrates that our material can still efficiently generate reactive oxygen species even in an oxygen-free environment.

[0023] Gas chromatography was used to verify whether the iridium complex produced hydrogen gas. The iridium complex was dissolved in an aqueous solution and placed in a sealed bottle, which was then irradiated with a 660 nm laser. After irradiation, the gas was collected for hydrogen detection. Figure 7 This shows the hydrogen release from iridium complexes under different light exposure times. The amount of hydrogen produced by the iridium complexes significantly increases with prolonged irradiation time, indicating that iridium complexes can indeed produce hydrogen under light exposure.

[0024] The phototoxicity indices of Ir@PPEG-MeEPO and Ir@PPEG under different oxygen concentrations, such as hypoxia (<1%) and normoxic (21%), are shown below:

[0025] Example 4 Evaluation of the cell-killing effect of Ir@PPEG-MeEPO 4T1 cells were seeded at a density of 10,000 cells / well in 96-well plates and cultured for 12 h. The old medium was replaced with fresh medium containing different concentrations of Ir@PPEG-MeEPO. The cells were then divided into four groups: Group 1 was incubated for 4 h followed by irradiation with a 660 nm laser under normoxic conditions for 3 min; Group 2 was incubated under hypoxic conditions for 4 h followed by irradiation with a 660 nm laser for 3 min; Group 3 was incubated for another 24 h; and Group 4 was incubated for another 24 h under hypoxic conditions. Cell viability was finally assessed using the MTT assay.

[0026] The killing effect of Ir@PPEG-MeEPO on 4T1 cells under different conditions and concentrations is as follows: Figure 8 As shown, the concentration of Ir@PPEG-MeEPO tested under dark conditions exhibited low toxicity to 4T1 cells, while its cytotoxicity under light conditions was concentration-dependent. Furthermore, at the same concentration, Ir@PPEG-MeEPO maintained high phototoxicity to 4T1 cells under hypoxic conditions, demonstrating that our material can maintain excellent photodynamic effects under hypoxic conditions.

[0027] Example 5 Evaluation of intracellular reactive oxygen species production by Ir@PPEG-MeEPO under different conditions Using DCFH-DA as a reactive oxygen species (ROS) indicator, confocal microscopy was used to detect ROS production in Ir@PPEG-MeEPO-incubated cells under different conditions. 4T1 cells were seeded into confocal microscopy dishes and incubated overnight. The original culture medium was replaced with fresh Ir@PPEG-MeEPO medium, and incubation continued for 4 h. Then, the old culture medium was replaced with fresh DCFH-DA medium, and incubation continued for 20 min. The experiment was divided into four groups based on different experimental conditions: Group 1 was irradiated with a 660 nm laser for 3 min under normoxic conditions; Group 2 was irradiated with a 660 nm laser for 3 min under hypoxic conditions; Group 3 was not irradiated under normoxic conditions; and Group 4 was not irradiated under hypoxic conditions. The confocal microscopy dishes were washed three times with PBS, and fresh culture medium was added. The fluorescence intensity within the cells was observed under a laser confocal microscope.

[0028] like Figure 9 The results show that Ir@PPEG-MeEPO, after being exposed to light, produced bright green fluorescence in cells, and continued to produce bright green fluorescence even under hypoxic conditions, indicating that Ir@PPEG-MeEPO can effectively generate reactive oxygen species in both hypoxic and normoxic environments. However, no green fluorescence was detected in Ir@PPEG-MeEPO that had not been exposed to light.

[0029] Example 6 Multimodal imaging assay of Ir@PPEG-MeEPO in 4T1 tumor-bearing mice Ir@PPEG-MeEPO was injected into tumor-bearing mice via the tail vein. Fluorescence images of the mice were acquired at different time points after injection using a small animal in vivo imaging system. In another group of mice, ultrasound and photoacoustic images were acquired at different time points after injection using a small animal photoacoustic imaging system. Finally, in the last group of mice, irradiation with a 660 nm laser for 10 min was performed 1 h after injection, and the temperature changes at the tumor site were tracked and recorded in real time using a thermal imager.

[0030] Multimodal imaging results of Ir@PPEG-MeEPO in 4T1 tumor-bearing mice are as follows: Figure 10 As shown. Near-infrared II region fluorescence imaging results are as follows. Figure 10 As shown in (a), after injection into mice, the material rapidly accumulated at the tumor site, reaching its maximum fluorescence intensity one hour later, subsequently weakening with prolonged metabolic time. The photoacoustic imaging results are as follows... Figure 10 As shown in (b), the photoacoustic signal reached its maximum value 1 hour after the material was injected into the mice, followed by a decline in photoacoustic signal intensity. The photoacoustic imaging results were similar to those of the two-zone fluorescence imaging results. The photothermal imaging results are as follows: Figure 10As shown in (c), the tumor site of the mouse was irradiated with a 660nm laser 1 h after injection of the material, and the temperature reached 51 ℃ after 10 min, indicating that the material has a significant photothermal imaging effect on the tumor site of the tumor-bearing mouse.

[0031] In summary, Ir@PPEG-MeEPO can target tumors and achieve fluorescence / photoacoustic / photothermal multimodal imaging.

[0032] Example 7 Evaluation of Ir@PPEG-MeEPO in 4T1 tumor-bearing mice for tumor therapy Ir@PPEG-MeEPO was injected into tumor-bearing mice via the tail vein. The mice were randomly divided into five groups of five: PBS group; PBS + light exposure group; Ir@PPEG-MeEPO group; Ir@PPEG + light exposure group; and Ir@PPEG-MeEPO + light exposure group. Mouse growth, body weight, and tumor volume were continuously observed and recorded. On day 14, the tumors were dissected and photographed.

[0033] Treatment outcomes in tumor-bearing mice as follows Figure 11 As shown. Figure 11 (a) shows the tumor growth inhibition in mice. The figure indicates that the Ir@PPEG-MeEPO+ light-irradiated group exhibited the highest tumor inhibition rate. Figure 10 (b) Images of tumors ex vivo in mice after 14 days of treatment. The images show that the tumors in the Ir@PPEG-MeEPO+ light-irradiated group were completely eliminated and there was no recurrence within 14 days.

[0034] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A multimodal therapeutic nanoparticle excited in the near-infrared II region, characterized in that, include: An iridium complex forms a core and an amphiphilic polymer coating the surface of the core; the structural formula of the iridium complex is: The structural formula of the amphiphilic polymer is: Where n = 60.

2. A method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region as described in claim 1, characterized in that, The method includes: The iridium complex was dissolved in an organic solvent to obtain an iridium complex solution; The iridium complex solution was added to the aqueous solution of the polymer, and the mixture was subjected to ultrasonication, dialysis, and centrifugation in sequence to obtain the near-infrared II excited multimodal therapeutic nanoparticles.

3. The method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region according to claim 2, characterized in that, The method for preparing the iridium complex includes: Under an inert atmosphere, compound DPTP and Ir(2-phenylpyridine)4Cl2 were added to a mixed solution of dichloromethane and methanol, and the mixture was refluxed and stirred. After the reaction was completed, the mixture was cooled to room temperature, excess potassium hexafluorophosphate was added, and the solution was filtered and evaporated to dryness to obtain the iridium complex. The structural formula of DPTP is as follows: 。 4. The method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region according to claim 2, characterized in that, The method for preparing the polymer includes: Under inert gas protection, 3-methyl-2-pyridone, p-nitrobenzyl bromide, potassium carbonate, potassium iodide, 18-crown ether and acetone were mixed to obtain a reaction mixture. The reaction mixture was extracted and evaporated to dryness to obtain compound A. Compound A was mixed with ammonium formate, palladium on carbon, and methanol, reacted overnight, and then extracted and evaporated to dryness to obtain compound B. Compound B and polymaleic anhydride were added to tetrahydrofuran under an inert atmosphere, the reaction mixture was refluxed overnight, and the precipitate yielded polymer P-MePYR. The polymer P-MePYR, 1-(3-dimethylpropyl)-3-ethylcarbodimethylamine hydrochloride, N-hydroxysuccinimide and ultra-dry N,N-dimethylformamide were stirred under an inert atmosphere, and amino polyethylene glycol 2000 was added. After the reaction was completed, the solvent was removed, dissolved, dialyzed and dried to obtain the product PPEG-MePYR. The polymer PPEG-MePYR was dissolved in an N,N-dimethylformamide solution, and an excess of methylene blue was added. The mixture was stirred at 0-4°C, irradiated with a 660 nm laser, dialyzed using a dialysis bag, and freeze-dried to obtain the polymer.

5. The method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region according to claim 2, characterized in that, The particle size of the near-infrared II excited multimodal diagnostic and therapeutic nanoparticles is 10-25 nm.

6. The method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region according to claim 3, characterized in that, The equivalent ratio of the compound DPTP to Ir(2-phenylpyridine)4Cl2 is 2:

1.

7. The method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region according to claim 2, characterized in that, The organic solvent is selected from any one of tetrahydrofuran, dichloromethane, and dimethyl sulfoxide.

8. The method for preparing multimodal therapeutic nanoparticles excited in the near-infrared II region according to claim 4, characterized in that, The inert gas is nitrogen.

9. The method for preparing near-infrared II excited multimodal therapeutic nanoparticles according to claim 4, characterized in that, The polymer P-MePYR, 1-(3-dimethylpropyl)-3-ethylcarbodimethylamine hydrochloride, N-hydroxysuccinimide, and ultra-dry N,N-dimethylformamide were stirred under an inert atmosphere, and amino polyethylene glycol 2000 was added. After the reaction was completed, the solvent was removed, the mixture was dissolved in ultrapure water, dialyzed, and then dried using a freeze dryer to obtain the product PPEG-MePYR, which specifically includes: The polymer P-MePYR, 1-(3-dimethylpropyl)-3-ethylcarbodimethylamine hydrochloride, N-hydroxysuccinimide, and ultra-dry N,N-dimethylformamide were stirred at room temperature for 10-50 minutes under an inert atmosphere. Amino polyethylene glycol 2000 was added, and the mixture was stirred at room temperature for 1-3 days. After the reaction was completed, the solvent was removed, and the product was dissolved in ultrapure water. The solution was then dialyzed using a dialysis bag for 2-3 days and then dried using a freeze dryer to obtain the product PPEG-MePYR.

10. The application of the near-infrared II excited multimodal diagnostic and therapeutic nanoparticles as described in claim 1 in the preparation of a photothermal synergistic immunodiagnostic and therapeutic reagent for tumors.

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