Preparation of a diagnostic and therapeutic agent with fluorescence / MR imaging and photodynamic therapy functions

Abstract

The present invention discloses a method for preparing a diagnostic and therapeutic agent with fluorescence / MR imaging and photodynamic therapy functions, and belongs to the field of materials science and biomedical technology. The technical problem to be solved by the present invention is to provide a method for preparing a diagnostic and therapeutic agent with fluorescence / MR imaging and photodynamic therapy functions. The present invention couples a hydrophobic fluorescent group with AIE characteristics with a hydrophilic manganese ion complex with magnetic resonance imaging capability to construct an amphiphilic nano diagnostic and therapeutic agent TBPN-AM molecule. The nano diagnostic and therapeutic agent TBPN-AM prepared by the present invention has good fluorescence and magnetic resonance imaging (MR) functions, and can efficiently target tumor cell mitochondria, thereby realizing specific labeling and detection of tumor cells. In addition, the nano diagnostic and therapeutic agent TBPN-AM can also generate two types of ROS under illumination conditions for PDT ablation of tumor cells, and effectively ablate tumor cells under normoxia (21% O2) and hypoxia (2% O2), thereby realizing accurate diagnosis and treatment of tumors in complex tumor microenvironments. The synthesis method of the diagnostic and therapeutic agent is simple, the raw materials are easily available, the synthesis conditions are easy to implement and control, and it can be mass-produced, showing great potential in clinical applications.

Description

Technical Field

[0001] The present invention belongs to the field of material science and biomedical technology, and specifically relates to the preparation of a diagnostic and therapeutic agent with fluorescence / MR imaging and photodynamic therapy functions. Background Art

[0002] At present, photodynamic therapy (PDT) has shown unique advantages in tumor treatment due to its advantages such as non-invasiveness, controllability and low toxicity and side effects. As an emerging treatment method that uses photosensitizers to produce highly toxic reactive oxygen species (ROS) under the irradiation of appropriate wavelength light sources to kill cancer cells, the treatment process of PDT can be summarized as follows: 1) The photosensitizer transitions from the ground state to the excited singlet state under light excitation; 2) The excited singlet photosensitizer reaches the excited triplet state through intersystem crossing (ISC); 3) The excited triplet photosensitizer generates ROS through energy transfer or electron transfer with oxygen; 4) ROS induces cancer cell death by interacting with nearby biological molecules. Studies have shown that the PDT treatment process can be divided into two categories: Type I: Through the excited triplet photosensitizer and oxygen or substrate, electron transfer or proton transfer is generated to generate different free radicals, such as superoxide anion radical (O2 -· ), hydroxyl radicals (·OH) or peroxides (O2 2- ) etc.; Type II: by exciting the triplet photosensitizer to directly transfer energy with oxygen to generate highly toxic singlet oxygen ( 1 O2).

[0003] In recent years, a variety of photosensitizers have been clinically approved for the treatment of diseases such as skin cancer and prostate cancer, such as porphyrins and dihydrochlorins. However, these photosensitizers are based on the type II mechanism for PDT treatment, that is, photosensitizers transfer light energy to the surrounding oxygen to produce highly toxic singlet oxygen ( 1 O2) to ablate tumor cells. It can be seen that these photosensitizers will further consume tissue oxygen and aggravate hypoxia during PDT treatment, thereby affecting the ability to generate ROS, resulting in unsatisfactory PDT treatment effects. In contrast, the type I PDT treatment process has a low dependence on oxygen and can generate ROS even in a hypoxic environment. It is worth noting that compared with type I PDT, the ROS generated by type II PDT has a longer lifespan. Therefore, designing a photosensitizer that combines type I and type II PDT, that is, combining the high ROS yield of type I photosensitizers with the low oxygen dependence of type II photosensitizers, to achieve efficient PDT treatment of tumors in hypoxic conditions is of great significance for the early treatment of tumors.

[0004] Studies have shown that imaging technology can not only provide diagnostic information, but also visualize the delivery and distribution of photosensitizers. It can be said that image guidance is crucial to determine the optimal time window for treatment. Among different imaging methods, fluorescence imaging has the advantages of high sensitivity, rapid feedback, and less tissue scattering. However, the limited penetration of fluorescence imaging hinders its clinical application. Relatively speaking, magnetic resonance (MR) imaging has higher spatial resolution and deeper penetration, and can provide anatomical or structural information non-invasively. However, the low sensitivity of MR imaging may affect its diagnostic accuracy. Therefore, the combination of fluorescence and MR imaging is expected to make up for their respective shortcomings and achieve complementary advantages. It can be said that molecular fluorescence / MR dual-modality imaging probes not only have the advantages of good biocompatibility, high imaging sensitivity and deep penetration, but also can further integrate imaging diagnosis with PDT treatment, which is expected to achieve accurate diagnosis and treatment of tumors, showing good development prospects. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a nano-diagnostic and therapeutic agent with strong tumor cell mitochondrial targeting specificity, fluorescence / MR imaging capability and the ability to produce highly toxic reactive oxygen species (ROS), so as to achieve tumor photodynamic therapy guided by dual-modality imaging of fluorescence and MR imaging.

[0006] A preparation of a diagnostic and therapeutic agent with fluorescence / MR imaging and photodynamic therapy functions comprises the following steps:

[0007] 1. Preparation of intermediate 1: 1.0 g to 10.0 g of 4,7-dibromo-2,1,3-benzothiadiazole, 0.1 g to 1.0 g of tetrakis(triphenylphosphine)palladium and 1.0 g to 10.0 g of potassium carbonate are uniformly mixed in 10 mL to 100 mL of tetrahydrofuran and 1 mL to 10 mL of water to obtain a reaction solution. 0.1 g to 1.0 g of 4-boric acid triphenylamine is slowly dissolved in 10 mL to 100 mL of tetrahydrofuran and slowly added dropwise to the above reaction solution. Under nitrogen protection, the resulting mixed solution is uniformly stirred at 50° C. to 150° C. for 5 to 50 hours. After the reaction is completed, the reaction solution is cooled to room temperature and extracted with ethyl acetate. Then, the organic layer is dried with sodium sulfate (Na2SO4) and purified by silica gel chromatography. Finally, the crude product was purified using ethyl acetate / petroleum ether in a volume ratio of 1:1 to 1:100 as an eluent to obtain an orange-red powdery intermediate 1;

[0008] 2. Preparation of intermediate 2: 1.0g to 10.0g of intermediate 1, 0.5g to 5.0g of pyridine-4-boric acid, 0.5g to 5.0g of potassium carbonate and 0.1g to 1.0g of 1,1′-bis(diphenylphosphino)ferrocenepalladium dichloride are uniformly mixed in a mixed solution consisting of 10mL to 100mL of dioxane and 10mL to 100mL of methanol. Under nitrogen protection, the reaction solution is uniformly stirred at 50°C to 150°C for 5 to 50h. After the reaction is completed, the reaction solution cooled to room temperature is extracted with dichloromethane. Then, the organic layer is collected and dried with Na2SO4, and purified by silica gel chromatography. Finally, ethyl acetate / petroleum ether with a volume ratio of 1:1 to 1:100 is used as an eluent to purify the crude product to obtain a red powder intermediate 2;

[0009] 3. Preparation of intermediate 3: 0.1g-1.0g of intermediate 2 and 0.1g-1.0g of 3-bromopropylamine were uniformly mixed in 1mL-10mL of o-dichlorobenzene, and the solution was uniformly stirred at 50℃-150℃ for 5-50h. After the reaction was completed, the reaction solution was cooled to room temperature, diluted with 10mL-100mL of ethyl acetate, desolventized, and vacuum dried to constant weight. Finally, a dark red powder intermediate 3 was obtained;

[0010] 4. Preparation of TBPN-A: 0.1g~1.0g of intermediate 3, 0.1g~1.0g of benzoyl isothiocyanate and 0.1g~1.0g of N,N-diisopropylethylamine are uniformly mixed in 1mL~10mL of dichloromethane, and the mixture is stirred at room temperature for 1~10min. After the reaction is completed, the reaction solution is extracted with dichloromethane. The organic layer is collected and dried over Na2SO4. Then, the organic layer is concentrated in vacuo and purified by silica gel chromatography. Finally, the crude product is purified using methanol / dichloromethane with a volume ratio of 1:1 to 1:100 as the eluent to obtain a dark red powder intermediate TBPN-A;

[0011] 5. Preparation of TBPN-AM: Evenly mix 0.1g~1.0gTBPN-A and 0.1g~1.0g manganese chloride (MnCl2) in 1mL~10mL ethanol and stir at 50℃~150℃ for 1~20h. After the reaction is completed, the reaction solution is cooled to room temperature and the ethanol is removed by rotary evaporation. Then, the crude product is dissolved in dichloromethane and washed with excess deionized water to purify the product. Finally, the organic layer is collected, dried over Na2SO4, and concentrated in vacuo to obtain a black powdered diagnostic and therapeutic agent TBPN-AM.

[0012] In the step 1, the molar ratio of 4-boric acid triphenylamine to 4,7-dibromo-2,1,3-benzothiadiazole is 1:1.2 to 1:2.0; the molar ratio of 4-boric acid triphenylamine to tetrakis(triphenylphosphine)palladium is 1:0.05 to 1:0.1; and the molar ratio of 4-boric acid triphenylamine to potassium carbonate is 1:2.0 to 1:3.0.

[0013] The reaction temperature in step 2 is 100-120° C.; the molar ratio of intermediate 1 to pyridine-4-boric acid is 1:1.0-1:1.5; the molar ratio of intermediate 1 to 1,1′-bis(diphenylphosphino)ferrocenepalladium dichloride is 1:0.05-1:0.12; and the molar ratio of intermediate 1 to potassium carbonate is 1:1.2-1:2.0.

[0014] The molar ratio of the intermediate 2 to 3-bromopropylamine in the step 3 is 1:1.0 to 1:1.5.

[0015] In the step 4, the molar ratio of the intermediate 3 to benzoyl isothiocyanate is 1:1.0 to 1:1.5.

[0016] In the step 5, the molar ratio of the intermediate TBPN-A to MnCl2 is 1:1.5 to 1:2.5.

[0017] The diagnostic and therapeutic agent TBPN-AM prepared in step 5 can form nanoparticles with good dispersibility in water, with a particle size of 60nm to 600nm and a surface charge of +15mv to +25mv.

[0018] The diagnostic and therapeutic agent TBPN-AM prepared in step 5 can form a complex with manganese ions through the aminopropyl-linked acyl thiourea and has MR imaging function, and the benzothiadiazole connected to triphenylamine and pyridine quaternary ammonium salt provides fluorescence imaging and photodynamic therapy functions.

[0019] The diagnostic and therapeutic agent TBPN-AM prepared by the present invention has the following advantages:

[0020] (1) TBPN-AM has the ability to target tumor cell mitochondria and has good fluorescence and MR imaging capabilities, and can effectively achieve fluorescence / MR dual-modality imaging of tumor cells.

[0021] (2) TBPN-AM can produce type I and II ROS under light conditions, which can then be used for PDT ablation treatment of tumor cells.

[0022] (3) TBPN-AM can effectively ablate tumor cells under both normoxic conditions (21% O2) and hypoxic conditions (2% O2), and is expected to achieve precise treatment of tumors in complex tumor microenvironments.

[0023] (4) The raw materials of TBPN-AM are easily available, and the synthesis conditions are easy to achieve and control. It has great potential in clinical applications and is expected to provide new ideas for the early diagnosis and precision treatment of tumors. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The synthetic route of the diagnostic and therapeutic agent TBPN-AM of the present invention is shown in FIG.

[0025] Figure 2 The intermediate 2 of the present invention 1 H NMR spectra;

[0026] Figure 3 The intermediate 3 of the present invention 1 H NMR spectra;

[0027] Figure 4 A is the intermediate TBPN-A of the present invention 1 H NMR spectra;

[0028] Figure 4 B is the intermediate TBPN-A of the present invention 13 C NMR spectra;

[0029] Figure 4 C is the HR-MS chart of the intermediate TBPN-A of the present invention;

[0030] Figure 5 A is the FTIR graph of TBPN-AM of the present invention;

[0031] Figure 5 B is the XPS graph of TBPN-AM of the present invention;

[0032] Figure 6 TBPN-AM of the present invention is a transmission electron microscope image;

[0033] Figure 7 A is the hydrated particle size diagram of TBPN-AM of the present invention;

[0034] Figure 7 B is the Zeta potential diagram of TBPN-AM of the present invention;

[0035] Figure 8 A is the ultraviolet absorption spectrum of TBPN-AM of the present invention;

[0036] Figure 8 B is the fluorescence emission spectrum of BPN-AM of the present invention;

[0037] Fig. 9 A is the luminescence spectrum of TBPN-AM of the present invention in DMSO / toluene mixtures with different toluene volume fractions;

[0038] Fig. 9 B is the relative luminous intensity (I / I0) diagram of TBPN-AM of the present invention;

[0039] Fig.10 A is the T1 magnetic resonance grayscale image of TBPN-AM of the present invention at different concentrations;

[0040] Fig.10 B is a linear relationship diagram of the T1 relaxation time of the present invention and different concentrations of TBPN-AM;

[0041] Fig.11 This is a fluorescence emission spectrum of TBPN-AM and DCFH-DA mixed under white light irradiation;

[0042] Fig.12 This is an absorption spectrum of TBPN-AM of the present invention mixed with 9,10-anthracenediyl-bis(methylene)-dimalonic acid (ABDA) and Bengal rose red (RB) under white light;

[0043] Fig.13 This is a fluorescence emission spectrum of TBPN-A and DHR-123 mixed under white light irradiation;

[0044] Fig.14 This is a confocal localization image of the 4T1 cells of the present invention after incubation with TBPN-AM and mitochondrial green fluorescent probe. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be further described below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] A preparation of a diagnostic and therapeutic agent with fluorescence / MR imaging and photodynamic therapy functions, comprising the following steps: Figure 1): (1) Preparation of intermediate 1: 3.516 g of 4,7-dibromo-2,1,3-benzothiadiazole, 0.693 g of tetrakis(triphenylphosphine)palladium and 2.56 g of potassium carbonate were uniformly mixed in a mixed solution consisting of 20 mL of tetrahydrofuran and 5 mL of water to obtain a reaction solution. 2.896 g of 4-triphenylamine borate was slowly dissolved in 20 mL of tetrahydrofuran, and the solution was slowly dripped into the above reaction solution. Under nitrogen protection, the obtained mixed solution was uniformly stirred at 100° C. for 12 h. After the reaction was completed and cooled to room temperature, the reaction solution was extracted with ethyl acetate. Then, the organic layer was collected and dried with sodium sulfate, and purified by silica gel chromatography. Finally, the crude product was purified using ethyl acetate / petroleum ether with a volume ratio of 1:10 as an eluent to obtain 3.5 g of orange-red powder intermediate 1 with a yield of about 70%.

[0047] (2) Preparation of intermediate 2: 3.53 g of intermediate 1, 1.1 g of pyridine-4-boric acid, 1.12 g of potassium carbonate and 0.5112 g of 1,1′-bis(diphenylphosphino)ferrocenepalladium dichloride were uniformly mixed in a mixed solution consisting of 30 mL of dioxane and 30 mL of methanol. Under nitrogen protection, the mixed solution was uniformly stirred at 110°C for 12 h. After the reaction was completed, the solution was cooled to room temperature and extracted with dichloromethane. Then, the organic layer was collected and dried with sodium sulfate, and purified by silica gel chromatography. Finally, the crude product was purified using ethyl acetate / petroleum ether with a volume ratio of 1:10 as the eluent to obtain 1.0 g of red powder intermediate 2 with a yield of about 30%. Figure 2 As shown, the NMR spectrum of intermediate 2 is: 1 H NMR (400MHz, DMSO-d6) δ8.73 (d, J = 5.4 Hz, 2H), 8.09 (dd, J = 18.4, 6.7 Hz, 3H), 7.95 (dd, J = 8.2, 5.9 Hz, 3H), 7.38–7.29 (m, 4H), 7.08 (dd, J = 8.8, 7.0 Hz, 9H).

[0048] (3) Preparation of Intermediate 3: 0.456 g of Intermediate 2 and 0.228 g of 3-bromopropylamine were uniformly mixed in 2 mL of o-dichlorobenzene, and the solution was uniformly stirred at 110°C for 10 h. After the reaction was completed, the reaction solution was cooled to room temperature and washed with 40 mL of ethyl acetate. Then, the treated reaction solution was dried in a vacuum at 40°C to constant weight to obtain 490.0 mg of dark red powder Intermediate 3, with a yield of about 95%. Figure 3As shown, the nuclear magnetic spectrum of intermediate 3 is: 1H NMR (400 MHz, DMSO-d6) δ9.23 (d, J = 7.1 Hz, 2H), 8.95 (d, J = 6.6 Hz, 2H), 8.51 (d, J = 7.6 Hz, 1H), 8.11–8.02 (m, 3H), 7.37 (d, J = 7.8 Hz, 4H), 7.13 (dd, J = 9.6, 3.3 Hz, 8H), 4.74 (t, J = 7.1 Hz, 2H), 2.92 (t, J = 7.4 Hz, 2H), 2.29 (q, J = 7.6, 6.9 Hz, 2H).

[0049] (4) Preparation of TBPN-A: 0.514 g of intermediate 3, 164.0 μL of benzoyl isothiocyanate and 209 μL of N,N-diisopropylethylamine were uniformly mixed in 5 mL of dichloromethane, and the mixture was stirred at room temperature for 5 minutes. After the reaction was completed, the reaction solution was extracted with dichloromethane. The organic layer was collected and dried over sodium sulfate. Then, the organic layer was concentrated in vacuo and purified by silica gel chromatography. Finally, the crude product was purified using methanol / dichloromethane with a volume ratio of 1:50 as the eluent to obtain 70.0 mg of dark red solid intermediate TBPN-A with a yield of about 10%. Figure 4 As shown, the NMR spectrum of the intermediate TBPN-A is: 1 HNMR (400MHz, DMSO-d6) δ9.26(d,J=6.5Hz,2H),8.91(d,J=6.7Hz,2H),8.46(d,J=7.6Hz,1H),8.01(dd,J=8.1,4.6Hz,3H),7.76(d,J=7.6Hz,2H ),7.50(t,J=7.5Hz,1H),7.36(dt,J=15.1,7.9Hz,6H),7.17–7.04(m,8H),4.77(t,J=6.6Hz,2H),3.82(q,J=6.4Hz,2H),2.45(t,J=6.8Hz,2H); 13 C NMR (101MHz, DMSO-D6) δ180.37,167.61,153.20,152.59,151.48,148.44,146.61,144.66,136.39,132.89,132.28 ,131.88,130.68,129.84,129.01,128.35,128.17,126.69,126.18,125.01,124.10,121.47,58.77,42.05,28.80; C 40 H 33 N6OS 2+ [M] +HRMS m / z calculated value: 677.2152, found value: 677.2154.

[0050] (5) Preparation of TBPN-AM: 0.067 g of TBPN-B and 0.0252 g of manganese chloride were uniformly mixed in 2 mL of ethanol, and the mixture was stirred at 70 °C for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, and the ethanol was removed by rotary evaporation. Next, the crude product was dissolved in dichloromethane, and the excess manganese ions were washed with water several times to purify the product. Finally, the organic layer was collected, dried over sodium sulfate and concentrated in vacuo to obtain a black powder compound: TBPN-AM. Fourier transform infrared spectroscopy showed that the FTIR spectrum of TBPN-AM at 3240 cm -1 The typical NH stretch disappears ( Figure 5 A). Moreover, there are two peaks at the Mn2p orbital in the XPS spectrum of TBPN-AM. 3 / 2 The characteristic peaks appearing at the main peak and at Mn2p 1 / 2 The main peak has a characteristic peak ( Figure 5 B) All prove the successful preparation of TBPN-AM.

[0051] After analyzing the shape and dispersibility of TBPN-AM in aqueous solution by transmission electron microscopy, it was found that TBPN-AM was in the form of nanoparticles in water with an average particle size of 175nm ( Figure 6 The Malvern particle size test results showed that the average hydrated particle size of TBPN-AM was 207.2±5.5nm and the PDI was 0.165 ( Figure 7 A), the narrow particle size distribution and small PDI indicate that the hydrated particle size of TBPN-AM is uniform and has good dispersibility. In addition, the Zeta potential test results show that the surface potential of TBPN-AM is +19.9±0.69mV ( Figure 7 B).

[0052] After being illuminated, the diagnostic and therapeutic agent TBPN-AM with fluorescence / MR imaging and photodynamic therapy functions can emit red fluorescence. Therefore, the fluorescence curve of TBPN-AM was tested using a fluorescence spectrometer. Figure 8 As shown, TBPN-AM shows a maximum absorption peak at 500 nm and a strong fluorescence emission peak at 706 nm. It is worth noting that TBPN-AM hardly emits fluorescence in DMSO, but its fluorescence intensity increases with the increase of toluene volume content in the solvent ( Fig. 9 A). It is calculated that when the volume content of toluene is 99%, the fluorescence intensity increment of TBPN-AM is 78 times ( Fig. 9 B), indicating that TBPN-AM has good AIE performance. In vitro magnetic resonance imaging results show ( Fig.10 ), the brightness of TBPN-AM aqueous solution gradually increases with the increase of its concentration, and the calculated longitudinal relaxation rate (r1) is 13.83mM -1 S -1 , indicating that TBPN-AM has good T1 MR imaging capabilities.

[0053] The total ROS generation capacity of TBPN-AM in PBS was evaluated by the fluorescence on-degree of DCFH. Fig.11 In the PBS solution where TBPN-AM and DCFH-DA coexist, the fluorescence intensity of DCFH gradually increases with the extension of illumination time, indicating that TBPN-AM generates ROS in PBS, and its oxygen production capacity is much greater than that of RB. 1 The test results of O2 type show that ( Fig.12 ), after being irradiated with TBPN-AM, the characteristic absorption peak (400-800nm) of 9,10-anthracenediyl-bis(methylene)-dimalonic acid (ABDA) rapidly weakened. 1 The O2 yield was much higher than that of RB, indicating that TBPN-AM was produced through type II 1 Next, DHR 123 was used to evaluate the O2 production of TBPN-AM in PBS solution. -· The ability results show that ( Fig.13 ), the fluorescence intensity of DHR 123 gradually increased with the increase of illumination time, indicating that TBPN-AM produces O2 through type I -· .

[0054] Finally, Mito Tracker green was used to further examine the localization effect of TBPN-AM on organelles. Fig.14 The fluorescence of TBPN-AM overlaps with that of Mito Tracker green, and the related fluorescence intensity also shows a high Pearson coefficient (R=0.90), which proves that TBPN-AM has a strong targeting effect on the mitochondria of 4T1 cells.

Claims

1. A method for preparing a diagnostic and therapeutic agent TBPN-AM having fluorescence / MR imaging and photodynamic therapy functions, characterized in that The method comprises the following steps: (1) Preparation of intermediate 1: 1.0 g to 10.0 g of 4,7-dibromo-2,1,3-benzothiadiazole, 0.1 g to 1.0 g of tetrakis(triphenylphosphine)palladium and 1.0 g to 10.0 g of potassium carbonate are uniformly mixed in 10 mL to 100 mL of tetrahydrofuran (THF) and 1 mL to 10 mL of water to obtain a reaction solution; 0.1 g to 1.0 g of 4-boric acid triphenylamine is slowly dissolved in 10 mL to 100 mL of THF and slowly added dropwise to the above reaction solution; under nitrogen protection, the obtained mixed solution is uniformly stirred at 50° C. to 150° C. for 5 to 50 h; after the reaction is completed, the reaction solution is cooled to room temperature and extracted with ethyl acetate; then, the organic layer is dried with sodium sulfate and purified by silica gel chromatography; finally, the crude product is purified using ethyl acetate / petroleum ether in a volume ratio of 1:1 to 1:100 as an eluent to obtain an orange-red powder intermediate 1. (2) Preparation of Intermediate 2: 1.0 g to 10.0 g of Intermediate 1, 0.5 g to 5.0 g of pyridine-4-boric acid, 0.5 g to 5.0 g of potassium carbonate and 0.1 g to 1.0 g of 1,1′-bis(diphenylphosphino)ferrocenepalladium dichloride were uniformly mixed in a mixed solution consisting of 10 mL to 100 mL of dioxane and 10 mL to 100 mL of methanol; under nitrogen protection, the reaction solution was uniformly stirred at 50° C. to 150° C. for 5 to 50 h; after the reaction was completed, the reaction solution cooled to room temperature was extracted with dichloromethane; then, the organic layer was collected and dried with sodium sulfate, and purified by silica gel chromatography; finally, the crude product was purified using ethyl acetate / petroleum ether in a volume ratio of 1:1 to 1:100 as an eluent to obtain red powdery Intermediate 2. (3) Preparation of intermediate 3: 0.1 g to 1.0 g of intermediate 2 and 0.1 g to 1.0 g of 3-bromopropylamine were uniformly mixed in 1 mL to 10 mL of o-dichlorobenzene, and the solution was uniformly stirred at 50° C. to 150° C. for 5 to 50 h. After the reaction was completed, the reaction solution was cooled to room temperature and diluted with 10 mL to 100 mL of ethyl acetate, desolventized, and vacuum dried to constant weight. Finally, a dark red powder of intermediate 3 was obtained. (4) Preparation of TBPN-A: 0.1 g to 1.0 g of intermediate 3, 0.1 g to 1.0 g of benzoyl isothiocyanate and 0.1 g to 1.0 g of N,N-diisopropylethylamine were uniformly mixed in 1 mL to 10 mL of dichloromethane, and the mixture was stirred at room temperature for 1 to 10 min. After the reaction was completed, the reaction solution was extracted with dichloromethane. The organic layer was collected and dried over sodium sulfate. Then, the organic layer was concentrated in vacuo and purified by silica gel chromatography. Finally, the crude product was purified using methanol / dichloromethane in a volume ratio of 1:1 to 1:100 as an eluent to obtain a dark red powder intermediate TBPN-A. (5) Preparation of TBPN-AM: 0.1 g to 1.0 g of TBPN-A and 0.1 g to 1.0 g of manganese chloride (MnCl2) were uniformly mixed in 1 mL to 10 mL of ethanol and stirred at 50°C to 150°C for 1 to 20 h. After the reaction was completed, the reaction solution was cooled to room temperature and the ethanol was removed by rotary evaporation. Then, the crude product was dissolved in dichloromethane and washed with excess deionized water to purify the product. Finally, the organic layer was collected, dried over sodium sulfate, and concentrated in vacuo to obtain a black powder diagnostic and therapeutic agent TBPN-AM.

2. A method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that In the step (1), the molar ratio of 4-boric acid triphenylamine to 4,7-dibromo-2,1,3-benzothiadiazole is 1:1.2 to 1:2.0; the molar ratio of 4-boric acid triphenylamine to tetrakis(triphenylphosphine)palladium is 1:0.05 to 1:0.1; and the molar ratio of 4-boric acid triphenylamine to potassium carbonate is 1:2.0 to 1:3.

0.

3. A method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that In the step (2), the reaction temperature is 100-120° C., the molar ratio of the intermediate 1 to pyridine-4-boric acid is 1:1.0-1:1.5; the molar ratio of the intermediate 1 to 1,1′-bis(diphenylphosphino)ferrocenepalladium dichloride is 1:0.05-1:0.12; and the molar ratio of the intermediate 1 to potassium carbonate is 1:1.2-1:2.

0.

4. A method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that In the step (3), the molar ratio of the intermediate 2 to 3-bromopropylamine is 1:1.0 to 1:1.

5.

5. A method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that In the step (4), the molar ratio of the intermediate 3 to benzoyl isothiocyanate is 1:1.0 to 1:1.

5.

6. A method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that In the step (5), the molar ratio of the intermediate TBPN-A to MnCl2 is 1:1.5 to 1:2.

5.

7. A method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that The diagnostic and therapeutic agent TBPN-AM prepared in step (5) can form well-dispersed nanoparticles in water, with a particle size of 60nm to 600nm and a surface charge of +15mv to +25mv.

8. The method for preparing a diagnostic and therapeutic agent having fluorescence / MR imaging and photodynamic therapy functions as claimed in claim 1, characterized in that The diagnostic and therapeutic agent TBPN-AM prepared in step (5) can form a complex with manganese ions through the aminopropyl-linked acyl thiourea and has MR imaging function, and the benzothiadiazole linked to triphenylamine and pyridine quaternary ammonium salt provides fluorescence imaging and photodynamic therapy functions.

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