Benzobithiadiazole derivative and application thereof in preparation of multi-mode light diagnosis and treatment agent

Abstract

The invention discloses a benzobithiadiazole derivative of which the structural general formula is as follows: # imgabs0. The benzobithiadiazole derivative prepared by the preparation method disclosed by the invention has relatively strong near-infrared second-region emission, near-infrared first-region absorption, photothermal conversion capability and active oxygen generation capability so as to meet the application requirements of multi-mode light diagnosis and treatment.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical engineering technology, and specifically relates to a benzobisthiadiazole derivative and an application thereof in the preparation of a multimodal optical diagnostic and therapeutic agent. Background Art

[0002] In the past few decades, cancer has become one of the most serious threats to human health. However, traditional treatments, including surgical resection, chemotherapy, and radiotherapy, can cause great pain and serious side effects to patients. Therefore, it is urgent to develop more efficient tumor treatment methods. As an emerging treatment method, phototherapy relies on the different excited state energy dissipation of phototherapy agents during light excitation. It has high efficiency, non-invasiveness, spatiotemporal controllability, and good biosafety. It has been considered as a powerful tool for treating a wide range of superficial and localized tumors. As a special category of phototherapy, multimodal phototherapy involves fluorescence imaging (FLI), photoacoustic imaging (PAI), photothermal imaging (PTI), photodynamic therapy (PDT), and photothermal therapy (PTT). The clever integration of various phototherapy methods can bypass their respective limitations and has the collective advantage of improving the treatment effect. Therefore, it stands out from other therapies and has attracted widespread attention from researchers. In addition, the innovative "One-for-all" strategy of preparing single-molecule species with multiple photodiagnostic properties has gradually become a research hotspot due to its advantages such as clear composition structure, easy preparation, high reproducibility and excellent biocompatibility.

[0003] However, the fluorescence wavelength of the multimodal photodiagnostic agents reported so far is usually in the near-infrared window of 1 (NIR-I, 700-900nm), which seriously hinders its application in the diagnosis and treatment of deep tumors. In the near-infrared window of 2 (NIR-Ⅱ, 1000-1700nm), the fluorescence shows a deeper tissue penetration depth due to the significant decrease in photon absorption, photon scattering and spontaneous fluorescence intensity of biological tissues. However, due to the narrow molecular band gap in the near-infrared zone II, the non-radiative transition rate is greatly improved, resulting in an extremely low fluorescence quantum yield (QY) (<0.1%). In addition, in order to improve the water solubility and biocompatibility of organic materials, the most commonly used method is to prepare water-soluble nanoparticles with an amphiphilic polymer matrix. However, in this case, the molecules are aggregated in the nanoshell, and aggregation-induced quenching often occurs, resulting in further imbalance in the energy dissipation pathway. To achieve "One-for-all" phototherapy based on single molecules, the key is to balance multiple energy dissipation pathways of excited organic molecules, including radiative decay involving the FLI mode, intersystem crossing (ISC) pathway related to the PDT mode, and non-radiative thermal inactivation related to the PAI, PTI, and PTT modes. Aggregation-induced emission (AIE) active luminogens (AIEgens) have inherent advantages in the development of multimodal phototherapy agents because of the rich motion groups in their structures, which can be used as "knobs" to balance different energy dissipation pathways. At present, there is a lack of a comprehensive molecular design strategy for the development of NIR-II phototherapy agents in the field of multimodal phototherapy. Therefore, proposing a new molecular design strategy and developing new NIR-II AIEgens with cleverly balanced energy dissipation pathways is of great significance to the research progress of multimodal phototherapy agents. Summary of the invention

[0004] The object of the present invention is to provide a benzobisthiadiazole derivative.

[0005] Another object of the present invention is to provide a use of the benzobisthiadiazole derivative in the preparation of a multimodal photodiagnostic agent.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect of the present invention, a benzobisthiadiazole derivative is provided, the general structural formula of which is shown below:

[0008]

[0009] The π bridge is selected from one of the following structures:

[0010]

[0011] n is selected from 0 to 10 (preferably 0, 1, 2, 3, 4, 5);

[0012] The structure of the electron donor is shown below:

[0013]

[0014] R1 is selected from hydrogen, C1-C20 alkyl, and C1-C20 alkoxy.

[0015] Preferably, the structure of the electron donor is selected from one of the following structures:

[0016]

[0017] Most preferably, the structure of the benzobisthiadiazole derivative is selected from one of the following structures:

[0018]

[0019]

[0020] The second aspect of the present invention provides a water-soluble nanoparticle, which is prepared by the benzobisthiadiazole derivative and an amphiphilic polymer, wherein the amphiphilic polymer is selected from methoxy polyethylene glycol 2000-distearoyl phosphatidylethanolamine (DSPE-mPEG 2000 ), distearoylphosphatidylethanolamine-polyethylene glycol 2000-integrin targeting cyclic peptide (DSPE-PEG 2000 -cRGDfk) at least one.

[0021] The preparation method of the water-soluble nanoparticles comprises the following steps:

[0022] The benzobisthiadiazole derivative and the amphiphilic polymer in a mass ratio of 1:2 to 50 (preferably 1:20) are ultrasonically dissolved in tetrahydrofuran, the mixture is quickly injected into water, and intensely ultrasonicated in the water for at least 2 minutes; the mixed solution is dialyzed in deionized water for 1 to 24 hours (preferably 24 hours) to obtain the water-soluble nanoparticles.

[0023] The third aspect of the present invention provides a use of the benzobisthiadiazole derivative in the preparation of a multimodal photodiagnostic agent.

[0024] The fourth aspect of the present invention provides a use of the water-soluble nanoparticles in the preparation of a multimodal photodiagnostic agent.

[0025] The multimodal phototherapy agent is used in multimodal phototherapy integration, which means that a single material simultaneously contains multiple imaging modes and phototherapy modes. The imaging modes include: fluorescence imaging, photoacoustic imaging and photothermal imaging; the phototherapy modes include: photodynamic therapy and photothermal therapy.

[0026] The fluorescence emission wavelength of the multimodal photodiagnostic agent is in the near-infrared second region of 1000nm to 1700nm.

[0027] The multimodal photodiagnostic agent can be used in the integrated multimodal photodiagnosis and therapy for the treatment of in situ breast cancer in mammals.

[0028] The fifth aspect of the present invention provides a use of the benzobisthiadiazole derivative in the preparation of a drug for treating in situ breast cancer.

[0029] The sixth aspect of the present invention provides a use of the water-soluble nanoparticles in the preparation of a drug for treating in situ breast cancer.

[0030] Due to the adoption of the above technical solution, the present invention has the following advantages and beneficial effects:

[0031] The benzobisthiadiazole derivatives prepared by the present invention have strong near-infrared second zone emission, near-infrared first zone absorption, photothermal conversion ability and active oxygen generation ability, so as to meet the application requirements of multimodal photodiagnosis and treatment.

[0032] The present invention provides a design strategy for three-dimensional donor engineering, namely, adjusting the molecular band gap by changing the strength of the electron donor, adjusting the molecular distance by changing the size of the electron donor steric hindrance, and reducing the influence of water molecules by introducing hydrophobic groups on the electron donor. Based on this molecular design strategy, the present invention has developed a phototherapy agent that has high near-infrared zone II fluorescence brightness, high photothermal conversion capability, and strong reactive oxygen conversion capability, which can achieve near-infrared zone II fluorescence imaging, photoacoustic imaging, and photothermal imaging-guided photodynamic and photothermal treatment of in situ breast cancer. The phototherapy agent provides a powerful platform for the integration of multimodal phototherapy and provides new inspiration for the development of new near-infrared zone II phototherapy agents.

[0033] The present invention uses donor engineering to balance the design strategy of the energy dissipation pathway of near-infrared zone II molecules: Due to the rich selection of electron donor libraries, a solid foundation is laid for regulating molecular properties through donor engineering. By changing the strength of the electron donor, the size of the steric hindrance, and the strength of the hydrophobic effect, the molecular energy dissipation pathway can be effectively adjusted from three dimensions: the molecular level, the aggregation level, and the solvent level. On this basis, the molecular design strategy is used to solve the problem of imbalance in the energy dissipation pathway of near-infrared zone II molecules, thereby realizing near-infrared zone II multimodal light diagnosis and treatment of mammals.

[0034] The present invention adjusts the electron donor and the π bridge through three-dimensional donor engineering, optimizes the molecular performance, and realizes the preparation of organic small molecule fluorophores with near-infrared zone 1 absorption, near-infrared zone 2 emission, photothermal conversion ability, and reactive oxygen generation ability. After being prepared into water-soluble nanoparticles using amphiphilic polymers, the photodiagnostic agent can realize near-infrared zone 2 fluorescence imaging, photoacoustic imaging, and photothermal imaging-guided photodynamic and photothermal therapy for in situ breast cancer.

[0035] The benzobithiadiazole derivative provided by the present invention has near-infrared first region peak absorption (754nm) and near-infrared second region peak fluorescence emission (1114nm), wherein the compound OPITBT shows excellent aggregation-induced emission properties, and in a mixed solvent of 90% water and 10% tetrahydrofuran, the fluorescence intensity is enhanced by 21 times compared with the initial value. 2000 After being encapsulated and prepared into water-soluble nanoparticles OPITBT NPs, its fluorescence quantum yield was enhanced by 16 times compared with the molecular level, the absorption peak was red-shifted to 805nm, the photothermal conversion coefficient was as high as 28.8%, and it had a certain ability to generate active oxygen. 2000 And DSPE-PEG-cRGDfk encapsulation prepared into water-soluble nanoparticles OPITBT-RNPs, which have active tumor targeting capabilities. The water-soluble nanoparticles OPITBT-R NPs have excellent near-infrared zone II fluorescence signals under 808nm excitation, can penetrate 7mm chicken breast tissue in vitro, and achieve near-infrared zone II (LP1500nm) whole-body vascular imaging in mice. The water-soluble nanoparticles OPITBT-R NPs can achieve photodynamic-photothermal therapy guided by near-infrared zone II fluorescence-photoacoustic-photothermal imaging for in situ breast cancer under 808nm laser irradiation. The water-soluble nanoparticles OPITBT-R NPs have excellent biocompatibility and will not cause damage to the main organs of mice (heart, liver, spleen, lungs, and kidneys). BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the basic photophysical properties of compounds MPITBT, DPITBT and OPITBT in tetrahydrofuran solution.

[0037] Figure 2 This is a schematic diagram of the gas-phase ground state structure of compounds MPITBT, DPITBT and OPITBT optimized through theoretical calculations.

[0038] Figure 3 This is a schematic diagram of the electron distribution results of the lowest unoccupied orbital (LUMO) and the highest occupied orbital (HOMO) of the compounds MPITBT, DPITBT and OPITBT obtained through theoretical calculations.

[0039] Figure 4 This is a schematic diagram of the aggregation-induced emission property test of compounds MPITBT, DPITBT and OPITBT, recording the change of fluorescence intensity with the change of water content in a tetrahydrofuran / water mixed solution (10 μM).

[0040] Figure 5 This is a schematic diagram of the average particle size distribution results of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs measured in aqueous solution.

[0041] Figure 6 Schematic diagram of the basic photophysical properties of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs in aqueous solution.

[0042] Figure 7 is the near-infrared second-region fluorescence quantum yield of compounds MPITBT, DPITBT and OPITBT in tetrahydrofuran solution ( Figure 7 (shown in a) and the near-infrared second-region fluorescence quantum yield of its nanoparticle aqueous solution ( Figure 7 Schematic diagram shown in (b).

[0043] Figure 8 Schematic diagram of the photothermal conversion efficiency of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs.

[0044] Fig. 9 Schematic diagram of the photothermal stability cycle test results of nanoparticles OPITBT NPs and the commercial photothermal agent indocyanine green (ICG, used for stability control).

[0045] Fig.10 It is a schematic diagram of the reactive oxygen generation ability and its types of results of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs.

[0046] Fig.11 Schematic snapshot of molecular aggregates formed in water by kinetic simulation of compounds MPITBT, DPITBT and OPITBT.

[0047] Fig.12 This is a schematic diagram of the effects of different electron donors on the properties of molecular aggregation.

[0048] Fig.13 Schematic diagram of the test of basic photophysical properties of nanoparticles OPITBT-RNPs in aqueous solution.

[0049] Fig.14It is a schematic diagram of the particle size comparison and stability test of nanoparticles OPITBT-RNPs and OPITBT NPs.

[0050] Fig.15 Schematic diagram of the effect of OPITBT-R NPs as photodiagnostic agents in fluorescence-photoacoustic-photothermal imaging of in situ breast cancer tumors.

[0051] Fig.16 OPITBT-RNPs were used as phototherapy agents after single laser irradiation (808 nm, 0.8 W / cm 2 ) Schematic diagram of the relative tumor volume changes in mice after treatment and in the control group.

[0052] Fig.17 This is a schematic diagram of tumor tissue photos of the treatment group and the control group after 14 days of treatment with nanoparticles OPITBT-R NPs as phototherapy agents.

[0053] Fig.18 This is a schematic diagram of the physiological changes in tumor tissue in the treatment group and the control group after 14 days of treatment with OPITBT-R NPs as a phototherapy agent.

[0054] Fig.19 This is a schematic diagram of the weight changes of mice in the treatment group and the control group during 14 days of treatment with OPITBT-R NPs as a phototherapy agent.

[0055] Fig. 20 This is a schematic diagram of the physiological changes in the main organ tissues (heart, liver, spleen, lung, and kidney) in the treatment group and the control group after 14 days of treatment with nanoparticles OPITBT-R NPs as phototherapy agents.

[0056] Fig.21 This is a schematic diagram of the nuclear magnetic resonance hydrogen spectrum of the compound MPITBT.

[0057] Fig. 22 This is a schematic diagram of the carbon NMR spectrum of compound MPITBT.

[0058] Fig.23 It is a schematic diagram of the time-of-flight mass spectrum of compound MPITBT.

[0059] Fig.24 This is a schematic diagram of the H NMR spectrum of the compound DPITBT.

[0060] Fig.25 This is a schematic diagram of the carbon NMR spectrum of the compound DPITBT.

[0061] Fig.26 It is a schematic diagram of the time-of-flight mass spectrum of the compound DPITBT.

[0062] Fig. 27 This is a schematic diagram of the H NMR spectrum of the compound OPITBT.

[0063] Fig.28 This is a schematic diagram of the carbon NMR spectrum of the compound OPITBT.

[0064] Fig.29 It is a schematic diagram of the time-of-flight mass spectrum of compound OPITBT.

[0065] Fig.30 It is a schematic diagram of the design strategy of the fluorescent molecule OPITBT in the present invention and its preparation into nanoparticles OPITBT-RNPs for application in multimodal phototherapy of in situ breast cancer. DETAILED DESCRIPTION

[0066] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0067] Unless otherwise specified, the test methods used in the present invention are all conventional methods, and unless otherwise specified, the test materials used in the following examples are all purchased from conventional reagent stores.

[0068] Example 1

[0069] Synthesis route of compound MPITBT

[0070]

[0071] Under N2 atmosphere, compound 1 (717 mg, 1 mmol; the synthetic route of compound 1 refers to ZhichengYang, et.al.Chem.Eur.J.2021, 27, 14240–14249), compound 2 (185 mg, 0.25 mmol; purchased from Shanghai McLean Biochemical Technology Co., Ltd.), Pd(PPh3)2Cl2 (18 mg, 0.025 mmol) and 20 mL of toluene were added to a 100 mL pre-dried double-necked flask, reacted at 120°C for 12 hours, cooled to room temperature, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (1:2, v / v) as the eluent to obtain compound MPITBT as a dark green solid (yield of 70%). NMR and mass spectrometry are as follows Figures 21 to 23 As shown, Fig.21 This is a schematic diagram of the nuclear magnetic resonance hydrogen spectrum of the compound MPITBT. Fig. 22 This is a schematic diagram of the carbon NMR spectrum of compound MPITBT. Fig.23It is a schematic diagram of the time-of-flight mass spectrum of compound MPITBT. 1 HNMR(400MHz, CDCl3)δ7.28(s,2H),7.23(d,J=1.6Hz,4H),7.10(dd,J=9.6,2.6Hz,8H),7.05(d,J=1.9Hz,2H),6.90–6.84(m,10H),3.84(s,12H) ,2.61(d,J=6.9Hz,4H),1.44(s,12H),1.40–1.35(m,2H),1.02(dddq,J= 42.1,19.6,13.2,6.9Hz,16H),0.71–0.62(m,6H),0.51(t,J=7.3Hz,6H). 13 C NMR(151MHz,THF-d8)δ158.02,157.28,156.06,153.07,147.36,144.25,141.23,140.63,139.13,138.18,129.31,129.09,125.99,125.42,12 0.06,119.02,117.78,115.78,115.68,114.43,54.59,45.70,40.47,34 .41,32.43,28.48,25.56,25.30,24.21,24.08,22.71,13.41,10.04.MS for C 84 H 84 N6O4S6[M] + :calcd.1432.4878,found1432.4258.

[0072] Example 2

[0073] Synthesis route of compound DPITBT

[0074]

[0075] Under N2 atmosphere, compound 3 (235 mg, 1 mmol; compound 3 synthesis route reference Zhicheng Yang, et.al. Chem. Eur. J. 2021, 27, 14240–14249), diphenylamine (507 mg, 3 mmol), bis(dibenzylideneacetone) palladium (57 mg, 0.1 mmol), tri-tert-butylphosphine (60 mg, 0.3 mmol), potassium tert-butoxide (112 mg, 1 mmol) and 20 mL of toluene were added to a 100 mL pre-dried double-necked flask, reacted at 120 ° C for 12 hours, cooled to room temperature, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography with petroleum ether as the eluent to obtain compound 4 as a light yellow solid (yield 90%).

[0076] Under N2 atmosphere, compound 4 (367 mg, 1 mmol) and 20 mL of tetrahydrofuran were added to a 100 mL pre-dried Shrek tube, cooled at -78 °C for 1 hour, then n-butyl lithium (0.5 mL, 2M / n-hexane, 2 mmol) was added dropwise, reacted at -78 °C for 1 hour, and then tributyltin chloride (325 mg, 1 mmol) was added to react at room temperature for 12 hours. After the reaction, the solvent was dried, washed with deionized water and dried to obtain compound 5, which was not further purified and characterized.

[0077] Under N2 atmosphere, compound 5 (657 mg, 1 mmol), compound 2 (185 mg, 0.25 mmol), Pd(PPh3)2Cl2 (18 mg, 0.025 mmol) and 20 mL of toluene were added to a 100 mL pre-dried double-necked flask, reacted at 120°C for 12 hours, cooled to room temperature, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (1:3, v / v) as the eluent to obtain compound DPITBT as a dark green solid (yield 68%). NMR and mass spectrometry are shown in Figures 24-26 As shown, Fig.24 This is a schematic diagram of the H NMR spectrum of the compound DPITBT. Fig.25 This is a schematic diagram of the carbon NMR spectrum of the compound DPITBT. Fig.26 It is a schematic diagram of the time-of-flight mass spectrum of the compound DPITBT. 1H NMR (600MHz, CD2Cl2) δ7.31(d,J=8.4Hz,4H),7.29–7.24(m,10H),7.18(d,J=2.1Hz,2H),7.15–7.10(m,8H),7.03(dd,J=8.1,6.9Hz,4H),6.97(dd,J= 8.1,2.1Hz,2H),2.58(d,J=7.0Hz,4H),1.44(s,12H),1.36(q,J=6.6Hz,2H ),1.17–0.84(m,16H),0.66(td,J=7.1,2.1Hz,6H),0.51(t,J=7.4Hz,6H). 13 CNMR(151MHz,CDCl3)δ158.57,157.42,153.43,153.10,147.92,145.88, 144.68,143.34,141.00,139.13,131.42,129.22,125.98,123.99,123.3 8,122.61,119.44,118.84,118.08,116.05,45.97,40.54,34.41,32.44, 28.55,28.27,26.91,25.97,25.59,22.78,17.29,14.01,13.60,10.61.MS for C 80 H 76 N6S6[M] + :calcd.1312.4456,found 1312.3545.

[0078] Example 3

[0079] Synthesis route of compound OPITBT

[0080]

[0081] Under N2 atmosphere, compound 3 (235 mg, 1 mmol), bis(4-(2,4,4-trimethyl-2-pentyl)phenyl)amine (1181 mg, 3 mmol), bis(dibenzylideneacetone)palladium (57 mg, 0.1 mmol), tri-tert-butylphosphine (60 mg, 0.3 mmol), potassium tert-butoxide (112 mg, 1 mmol) and 30 mL of toluene were added to a 100 mL pre-dried two-necked flask, reacted at 120°C for 12 hours, cooled to room temperature, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using petroleum ether as the eluent to obtain compound 6 as a light yellow solid (yield 90%).

[0082] Under N2 atmosphere, compound 6 (592 mg, 1 mmol) and 20 mL of tetrahydrofuran were added to a 100 mL pre-dried Shrek tube, cooled at -78 °C for 1 hour, then n-butyl lithium (0.5 mL, 2M / n-hexane, 2 mmol) was added dropwise, reacted at -78 °C for 1 hour, and then tributyltin chloride (325 mg, 1 mmol) was added to react at room temperature for 12 hours. After the reaction, the solvent was dried, washed with deionized water and dried to obtain compound 7, which was not further purified and characterized.

[0083] Under N2 atmosphere, compound 7 (881 mg, 1 mmol), compound 2 (185 mg, 0.25 mmol), Pd(PPh3)2Cl2 (18 mg, 0.025 mmol) and 20 mL of toluene were added to a 100 mL pre-dried double-necked flask, reacted at 120°C for 12 hours, cooled to room temperature, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (2:5, v / v) as the eluent to obtain compound OPITBT as a dark green solid (yield 40%). NMR and mass spectrometry are shown in Figure 2. Figures 27-29 As shown, Fig. 27 This is a schematic diagram of the H NMR spectrum of the compound OPITBT. Fig.28 This is a schematic diagram of the carbon NMR spectrum of the compound OPITBT. Fig.29 It is a schematic diagram of the time-of-flight mass spectrum of compound OPITBT. 1 H NMR (600MHz, CD2Cl2) δ7.23–7.14(m,14H),6.97–6.92(m,10H),6.87(dd,J=8.1,2.1Hz,2H),2.48(d,J=7.1Hz,4H),1.6 5(s,8H),1.30(d,J=8.8Hz,38H),1.04–0.79(m,16H),0.68(s,36H),0.57(td,J=7.0,2.0Hz,6H),0.41(t,J=7.4Hz,6H). 13C NMR(151MHz,THF-d8)δ158.41,157.28,153.07,146.52,145.36,144.29,143.99 ,140.54,138.95,130.55,129.19,126.91,125.55,123.42,123.39,122.26,119 .08,117.97,117.80,115.79,56.95,45.72,40.48,37.91,34.42,32.43,32.11, 31.21,31.00,28.80,28.48,25.56,25.24,24.22,24.08,22.71,13.42,10.04.MS for C 112 H 141 N6S6[M+H] + :calcd.1762.9571,found 1762.8650.

[0084] Example 4

[0085] UV Absorption-Fluorescence Emission Spectra of Benzobisthiadiazole Derivatives in Tetrahydrofuran Solutions and Determination of Molar Extinction Coefficients

[0086] The UV absorption spectra and molar extinction coefficients of compounds MPITBT, DPITBT and OPITBT in tetrahydrofuran solution were measured using a Shimadzu UV-3600Plus UV-Vis-NIR absorption spectrometer, and the fluorescence emission spectra were measured using an Edinburgh Instruments FLS1000 fluorescence spectrometer.

[0087] Figure 1 The figure is a schematic diagram of the basic photophysical properties of compounds MPITBT, DPITBT and OPITBT in tetrahydrofuran solution, wherein a is a schematic diagram of the normalized ultraviolet absorption-fluorescence emission spectra of compounds MPITBT, DPITBT and OPITBT, the horizontal axis represents the wavelength (in nanometers), the left vertical axis represents the normalized absorbance, and the right vertical axis represents the normalized fluorescence intensity; b is a schematic diagram of the molar extinction coefficient of compounds MPITBT, DPITBT and OPITBT in tetrahydrofuran solution; the horizontal axis represents the concentration (in μM), the vertical axis represents the absorbance, and the calculated slope is the molar extinction coefficient of the compound. Figure 1 From a, we can conclude that the maximum absorption wavelengths of compounds MPITBT, DPITBT and OPITBT are 763, 736 and 754 nm, respectively, and the maximum emission wavelengths are 1122, 1101 and 1114 nm, respectively. This indicates that the absorption and emission wavelengths of the three compounds gradually red-shift with the increase of the electron donor intensity, and all exhibit near-infrared absorption in the first region and near-infrared emission in the second region. Figure 1 From b, it can be concluded that the molar extinction coefficients of compounds MPITBT, DPITBT and OPITBT at the absorption peak are 1.80×10 4 , 1.83×10 4 , 1.93×10 4 M -1 cm -1 , all showing strong light absorption ability in the near-infrared region.

[0088] Example 5

[0089] Theoretical Calculation of Molecular Structures of Benzobithiadiazole Derivatives

[0090] The Gaussian 16 software package uses B3LYP density functional theory and 6-31g(d) basis set to optimize the ground state geometry of compounds MPITBT, DPITBT and OPITBT. The optimized gas phase ground state structures, HOMO and LUMO electronic distributions of the three compounds are obtained. The calculation results are shown in Figure 2 , 3 shown. Figure 2 This is a schematic diagram of the gas-phase ground state structure of compounds MPITBT, DPITBT and OPITBT optimized through theoretical calculations. Figure 3 This is a schematic diagram of the electron distribution of the lowest unoccupied orbital (LUMO) and the highest occupied orbital (HOMO) of the compounds MPITBT, DPITBT and OPITBT obtained through theoretical calculations. Figure 2 It can be seen from the figure that among the three molecular structures, the benzobithiadiazole core and the thiophene groups on both sides show a larger dihedral angle (>45°). The twisted molecular structure is conducive to reducing the intermolecular π interaction. In addition, the dihedral angles at the thiophene and indenothiophene are reduced, which is conducive to enhancing the molecular conjugation and improving the light absorption capacity. Figure 3 It can be seen that the band gaps of the three compounds gradually decrease with the increase of electron donor intensity. OPITBT has a moderate band gap width of 1.21 eV, which achieves a good balance between the non-radiative dissipation rate and the absorption and emission wavelength.

[0091] Example 6

[0092] Aggregation-induced emission properties of benzobisthiadiazole derivatives

[0093] By preparing tetrahydrofuran / water mixed solutions with different water contents (water content is indicated by f) with the same compound concentration (10 μM), w indicates), test f w The fluorescence intensity was recorded every 10% change from 0% to 90%. Figure 4 As shown, Figure 4This is a schematic diagram of the aggregation-induced emission properties of compounds MPITBT, DPITBT and OPITBT, recording the changes in fluorescence intensity as the water content changes in a tetrahydrofuran / water mixed solution (10μM). The horizontal axis represents the water content, and the vertical axis represents the fluorescence intensity. It can be seen from the figure that the three compounds all increase with the change of f w As the solubility increases, the solubility decreases, and the fluorescence intensity of the aggregated state increases significantly, showing obvious aggregation-induced emission characteristics. However, it is worth noting that the fluorescence intensity of OPITBT is w =90%, the fluorescence intensity increased 21 times compared with the initial value, which was significantly higher than the other two compounds.

[0094] Example 7

[0095] The method for preparing water-soluble nanoparticles of benzobisthiadiazole derivatives comprises the following steps:

[0096] 1 mg of compound MPITBT and 20 mg of amphiphilic polymer methoxypolyethylene glycol 2000-distearoylphosphatidylethanolamine (DSPE-mPEG 2000 , CAS No. 147867-65-0; purchased from Xi'an Kaixin Biotechnology Co., Ltd.) was ultrasonically dissolved in 1 mL of tetrahydrofuran, and the mixture was quickly injected into 9 mL of water and vigorously ultrasonicated in water for 2 minutes. The mixed solution was transferred to a dialysis bag and dialyzed in a large amount of deionized water for 24 hours to obtain stable water-soluble nanoparticles MPITBT NPs.

[0097] 1 mg of the compound DPITBT and 20 mg of the amphiphilic polymer DSPE-mPEG 2000 Ultrasonic solution was dissolved in 1 mL of tetrahydrofuran, and the mixture was quickly injected into 9 mL of water, and ultrasonicated vigorously in water for 2 minutes. The mixed solution was transferred to a dialysis bag and dialyzed in a large amount of deionized water for 24 hours to obtain stable water-soluble nanoparticles DPITBT NPs.

[0098] 1 mg of compound OPITBT and 20 mg of amphiphilic polymer DSPE-mPEG 2000 Ultrasonic solution was dissolved in 1 mL of tetrahydrofuran, and the mixture was quickly injected into 9 mL of water, and the mixture was vigorously ultrasonicated in water for 2 minutes. The mixed solution was transferred to a dialysis bag and dialyzed in a large amount of deionized water for 24 hours to obtain stable water-soluble nanoparticles OPITBT NPs.

[0099] The average particle size distribution of the encapsulated nanoparticles was determined by dynamic light scattering. The test results are as follows: Figure 5 As shown, Figure 5The figure is a schematic diagram of the average particle size distribution of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs measured in aqueous solution. The average particle sizes of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs are 135.9, 130.7 and 139.8 nm, respectively, and the polymer dispersibility index (PDI) is less than 0.3. The TEM images of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs all show spherical nanoparticles. The above results all indicate that stable water-soluble nanoparticles have been successfully prepared.

[0100] Example 8

[0101] UV absorption-fluorescence emission spectra of water-soluble nanoparticles of benzobithiadiazole derivatives in water and determination of molar extinction coefficient

[0102] The determination method is the same as that of benzobithiadiazole derivatives. The test results are as follows: Figure 6 As shown, Figure 6 Schematic diagram of the basic photophysical properties of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs in aqueous solution, where a is a schematic diagram of the normalized UV absorption-fluorescence emission spectra of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs, the horizontal axis represents the wavelength (in nanometers), the left vertical axis represents the normalized absorbance, and the right vertical axis represents the normalized fluorescence intensity. b is a schematic diagram of the molar extinction coefficient of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs at 808nm. The horizontal axis represents the concentration (in μM), the vertical axis represents the absorbance, and the calculated slope is the molar extinction coefficient of the compound. After the compounds MPITBT, DPITBT and OPITBT were prepared into nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs, the fluorescence peak wavelength did not change significantly, but the absorption wavelength was significantly red-shifted to around 800nm. Since 808nm is considered to be the best excitation wavelength in the near-infrared window, the molar extinction coefficient of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs at 808nm was calculated. The nanoparticles OPITBT NPs showed a peak extinction coefficient of 1.72×10 4 M -1 cm -1 High molar extinction coefficient, the highest among the three.

[0103] Example 9

[0104] Near-infrared fluorescence quantum yield test of benzobisthiadiazole derivatives and their water-soluble nanoparticles

[0105] 1-Benzothioperchloric acid (near-infrared fluorescent dye IR-26) was used as a reference fluorophore (QY = 0.5%). For reference calibration, IR-26 was dissolved in 1,2-dichloroethane and diluted to five samples with absorbance values ​​of 0.1-0.01 at 808 nm. Then, IR-26 containing five DCE solutions with linear interval concentrations were transferred one by one to a fluorescence cuvette with a 10 mm optical path, and an 808 nm infrared semiconductor laser was used as the excitation source to record their emission spectra. The emission spectra of all five samples were integrated in the 1000-1700 nm region. The corresponding absorbance values ​​(808 nm) were plotted against the integrated fluorescence intensity and fitted with a linear function. The same steps were used for the compounds MPITBT, DPITBT, and OPITBT to obtain four linear functions. The slopes of these straight lines were used to calculate the fluorescence quantum yield of the samples according to the following equation:

[0106]

[0107] Among them, QY sample is the fluorescence quantum yield of the sample, QY ref is the fluorescence quantum yield of the reference fluorophore, slope sample and slope ref are the slopes of the lines for the sample and reference fluorophores, respectively, and n sample and n ref are the refractive indices of tetrahydrofuran and 1,2-dichloroethane, respectively.

[0108] The fluorescence quantum yield measurement of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs is the same as the above measurement method.

[0109] The results are as follows Figure 7 As shown, Figure 7 is the near-infrared second-region fluorescence quantum yield of compounds MPITBT, DPITBT and OPITBT in tetrahydrofuran solution ( Figure 7 (shown in a) and the near-infrared second-region fluorescence quantum yield of its nanoparticle aqueous solution ( Figure 7 (b) Schematic diagram. Wherein: the abscissa represents the absorbance at 808nm, and the ordinate represents the integrated area of ​​fluorescence intensity. Since the compounds MPITBT, DPITBT and OPITBT all have aggregation-induced emission characteristics, the fluorescence intensity is significantly enhanced due to molecular aggregation after being prepared into water-soluble nanoparticles, especially the near-infrared second-zone fluorescence quantum yield of nanoparticles OPITBT NPs is as high as 1.1%, which is 16 times higher than that of the molecular state, showing great potential for near-infrared second-zone fluorescence imaging.

[0110] Example 10

[0111] In vitro photothermal conversion performance test of water-soluble nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs

[0112] The nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs aqueous solution (50 μM) were heated at 0.8 W / cm 2 The intensity of the laser was irradiated with 808nm laser, and the temperature change was recorded every 30 seconds until the temperature reached the highest point, and the infrared thermal image of the sample tube was recorded at the same time. The photothermal conversion efficiency test was carried out in a 50μM aqueous solution. The sample was irradiated with 808nm laser (0.8W / cm 2 ) for 5 minutes and then cooled to room temperature. The photothermal conversion efficiency (η) can be calculated by the following formula:

[0113]

[0114] Where h is the heat transfer coefficient, s is the surface area of ​​the container, and ΔT max is the temperature difference between the highest temperature and room temperature, I is the laser power, A is the absorbance of the nanoparticle solution at 808 nm, Q s is the heat change of water in the system. λ is the absorbance of the nanoparticles at 808 nm. The unknown hs value is calculated by the following formula: hs = ∑ i m i C p,i / K, where m represents the mass of the aqueous solution and C represents the specific heat capacity of water. K is calculated from the linear data of the time and -lnθ curve, and the formula is t = -Klnθ (θ is defined as the ratio of ΔT to ΔT max Qs is calculated by the same method from the time variation of water on the cooling curve. 2 ) laser irradiation, the photothermal stability of OPITBTNPs was evaluated by five heating-cooling cycles, with each heating / cooling time being kept at 3 min.

[0115] The photothermal conversion efficiency results are as follows Figure 8 As shown, Figure 8 The figure is a schematic diagram of the photothermal conversion efficiency of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs. It can be seen from the figure that the photothermal conversion efficiency of nanoparticles OPITBT NPs in aqueous solution is as high as 28.8%. The photothermal stability cycle test results are shown in Fig. 9 As shown, Fig. 9This is a schematic diagram of the photothermal stability cycle test results of nanoparticles OPITBT NPs and commercial photothermal agent indocyanine green (ICG, used for stability control). As can be seen from the figure, during the five photothermal cycles, the nanoparticles OPITBT NPs showed good photothermal stability. The photothermal heating performance of the commercial photothermal agent ICG became worse and worse with the increase in the number of cycles. The above results show that the nanoparticles OPITBTNPs have excellent potential for photothermal therapy applications.

[0116] Embodiment 11

[0117] In vitro reactive oxygen species generation performance test of water-soluble nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs

[0118] 2',7'-Dichlorodifluorofluorescein diacetate (DCFH-DA) was used as a reactive oxygen species (ROS) indicator to detect the activity of ROS under 808 nm laser irradiation (0.8 W / cm 2 ) under the total amount of ROS generated. In order to activate DCFH-DA, 2mL NaOH solution (10mM) was mixed with 0.5mL DCFH-DA solution (1mM, dissolved in ethanol), stirred at room temperature in the dark for 30 minutes, and 10mL PBS solution of pH 7.4 was added. The activated solution was mixed with nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs solution (DCFH: 5μM; MPITBT NPs: 15μM; DPITBT NPs: 15μM; OPITBT NPs: 15μM) and irradiated with 808nm laser for different times. The ROS sensitized by MPITBT NPs, DPITBT NPs and OPITBT NPs excited 525nm fluorescence signal with an excitation wavelength of 488nm by photoluminescence (PL) instrument.

[0119] In order to further distinguish the types of ROS generated by MPITBT NPs, DPITBT NPs and OPITBT NPs, 9,10-anthracene dioyl-bis(methylene) dimalic acid (ABDA), hydroxyphenylfluorescein (HPF) and dihydrorhodamine 123 (DHR123) were used as three other indicators to evaluate the ROS generated by MPITBT NPs, DPITBT NPs and OPITBT NPs under 808 nm laser irradiation, respectively. 1 O2, OH and O 2· -Ability. The specific operation is to mix ABDA solution with MPITBT NPs, DPITBT NPs and OPITBT NPs (ABDA: 50μM; MPITBT NPs: 5μM; DPITBT NPs: 5μM; OPITBT NPs: 5μM) in aqueous solution, and perform laser irradiation, and record the decrease in absorbance of ABDA at 378nm under different irradiation times. HPF (15μM) or DHR123 (50μM) as well as MPITBT NPs (5μM), DPITBT NPs (5μM) and OPITBT NPs (5μM) were added to PBS buffer solution and treated under the same laser irradiation conditions. The fluorescence signal of the indicator was monitored in the range of 500-600nm, and the excitation wavelength was 488nm. The test results of active oxygen generation performance are listed in Fig.10 . Fig.10 The figure is a schematic diagram showing the reactive oxygen generation capacity and types of nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs. Fig.10 As shown in a to d, the nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs all exhibit the ability to generate ROS, and the ROS are superoxide anion radicals. This Type-I ROS generation ability is less dependent on oxygen, which is beneficial for the nanoparticles MPITBT NPs, DPITBT NPs and OPITBT NPs to generate ROS and kill cancer cells in the hypoxic environment of the tumor.

[0120] Example 12

[0121] Structural Analysis of Aggregates of Benzobithiadiazole Derivatives

[0122] Nanoparticles OPITBT NPs exhibited the best fluorescence brightness (fluorescence quantum yield × molar extinction coefficient) and the best photothermal conversion ability (photothermal conversion efficiency × molar extinction coefficient) and a certain Type-I ROS generation ability, achieving a better balance of energy dissipation, which can be attributed to the effective molecular design strategy of the three-dimensional donor engineering. In order to study the effects of different electron donors on the aggregation state of DPITBT, MPITBT and OPITBT molecules, molecular dynamics simulations were performed using the GROMACS software package. In the simulation, the force field parameters of the dye molecules were OPLS force field, and the water molecule model was SPCE model. The time step was set to 2.0fs, and the cutoff distance for all non-bonded interactions was 1.2nm. The long-range electrostatic interaction was calculated by the particle mesh Ewald (PME) method, and the LJ tail correction was added to the energy and pressure. The temperature was controlled by a Nosé-Hoover thermostat with a coupling time constant of 0.5ps; the pressure was maintained at 1bar by a Parrinello-Rahman pressure controller with a coupling time of 2.0ps. Periodic boundary conditions are imposed in all directions.

[0123] In the present invention, 40 molecules were first placed in a cubic simulation box with a side length of 12 nm and conjugate gradient energy minimization was performed. Subsequently, the aggregate configuration was obtained by performing a 10 ns NVT ensemble simulation under vacuum conditions. Next, the aggregate was solvated with water molecules and energy minimized. Subsequently, a 200 ns NPT simulation was performed under 300 K and 1 bar conditions, and the trajectory data of the last 100 ns was analyzed, and the analysis results were visualized using the VMD software package.

[0124] Fig.11 The schematic diagram of the snapshot of molecular aggregates formed by the compounds MPITBT, DPITBT and OPITBT in water through kinetic simulation. Among them, a is a schematic diagram of the snapshot of molecular aggregates formed by the compound MPITBT in water through kinetic simulation. b is a schematic diagram of the snapshot of molecular aggregates formed by the compound DPITBT in water through kinetic simulation. c is a schematic diagram of the snapshot of molecular aggregates formed by the compound OPITBT in water through kinetic simulation.

[0125] Simulation analysis data such as Fig.12 As shown, Fig.12The figure is a schematic diagram of the effect of different electron donors on the performance of molecular aggregation, where a is a schematic diagram of the distribution of molecular distances within the aggregate, b is a schematic diagram of the distribution of water molecules outside the molecules in the aggregate, and c is a schematic diagram of the distribution of dihedral angles of the benzene ring on the molecular electron donor in the aggregate. The compound OPITBT shows the largest intermolecular stacking distance in the aggregated state, which is beneficial to reduce the intermolecular π interaction and improve the fluorescence quantum yield. On the other hand, the large intermolecular stacking distance also provides space for intramolecular movement, which is beneficial to enhance the photothermal conversion ability. In addition, the compound OPITBT shows obvious hydrophobic effects, greatly reducing the interaction between water molecules and molecules and improving the fluorescence quantum yield.

[0126] Embodiment 13

[0127] Preparation of Nanoparticles OPITBT-RNPs and Their Application in Multimodal Phototherapy

[0128] OPITBT NPs have strong near-infrared absorption at 808nm, bright near-infrared second-zone fluorescence, excellent photothermal conversion ability, and Type-I reactive oxygen generation ability, which can meet the needs of multimodal phototherapy and have great potential for multimodal phototherapy applications. Therefore, nanoparticles OPITBT-R NPs with active tumor targeting ability were prepared by doping tumor targeting materials and applied to multimodal phototherapy of in situ breast cancer in mice.

[0129] Preparation of nanoparticles OPITBT-R NPs: 1 mg of compound OPITBT, 16 mg of DSPE-mPEG 2000 and 4 mg distearoylphosphatidylethanolamine-polyethylene glycol 2000-integrin targeting cyclic peptide (DSPE-PEG 2000 -cRGDfk; purchased from Xi'an Ruixi Biotechnology Co., Ltd., item number R-9998-2k) was ultrasonically dissolved in 1 mL of tetrahydrofuran, and the mixture was quickly injected into 9 mL of water and vigorously ultrasonicated in water for 2 minutes. The mixed solution was transferred to a dialysis bag and dialyzed in a large amount of deionized water for 24 hours to obtain stable water-soluble nanoparticles OPITBT-R NPs. Fig.30 It is a schematic diagram of the design strategy of the fluorescent molecule OPITBT in the present invention and its preparation into nanoparticles OPITBT-R NPs for application in multimodal phototherapy of in situ breast cancer.

[0130] The basic photophysical properties of the prepared nanoparticles OPITBT-R NPs were tested, and the results were as follows Fig.13 shown. Fig.13This is a schematic diagram of the basic photophysical properties test of nanoparticles OPITBT-R NPs in aqueous solution. The maximum absorption wavelength of OPITBT-R NPs in aqueous solution is 805nm, and the maximum emission wavelength is 1065nm, which is consistent with the maximum absorption and emission wavelengths of OPITBT NPs in aqueous solution, indicating that DSPE-PEG 2000 The doping of -cRGDfk has no effect on the basic photophysical properties of OPITBT-R NPs. The particle size changes of OPITBT NPs and OPITBT-R NPs stored in water, phosphate buffered saline (PBS), Dulbecco's modified Eagle's medium (DMEM), and 10% bovine serum albumin (FBS) at 8°C for 7 days were compared. Fig.14 As shown, Fig.14 Figure 2 is a comparison of the particle size of OPITBT-R NPs and OPITBT NPs and a schematic diagram of the stability test. The particle size of OPITBT NPs and OPITBT-R NPs did not change significantly after being stored in the four media for 7 days, proving that they have good micelle stability.

[0131] Multimodal imaging of tumor tissue: A PBS solution of nanoparticles OPITBT-R NPs (1 mg / mL, 200 μL) was injected into mice bearing 4T1 breast tumors through the tail vein. At predetermined time points after injection (10 minutes, 6 hours, 12 hours, 24 hours, 36 hours and 48 hours), NIR-II fluorescence images were captured using a 1300nm long-pass filter of the NIR-II in vivo imaging system. The main organs (heart, liver, spleen, lungs and kidneys) and tumors were then removed, washed with saline and subjected to NIR-II fluorescence imaging. In vivo photoacoustic imaging was performed using the Vevo LAZER system at designated time points (0, 1, 6, 12, 24, 36 and 48 hours). Photothermal imaging was performed 24 hours after injection of the nanoparticle OPITBT-R NPs solution (1 mg / mL, 200 μL) by 808nm laser irradiation (0.8 W / cm 2 ) used an infrared camera to capture infrared thermal images. Mice injected with PBS under the same irradiation conditions served as the control group. The multimodal imaging results of tumor tissue are listed in Fig.15 middle. Fig.15 The figure is a schematic diagram of the effect of fluorescence-photoacoustic-photothermal imaging of in situ breast cancer tumors using nanoparticles OPITBT-R NPs as photodiagnostic agents, where a is a schematic diagram of near-infrared second-zone fluorescence imaging, b is a schematic diagram of photoacoustic imaging, and c is a schematic diagram of photothermal imaging. Fig.15 As shown, the three imaging modes can accurately locate tumor tissue, and different imaging modes can compensate for the limitations of accuracy and tissue penetration depth to achieve precise positioning.

[0132] Phototherapy of tumor tissue: Mice bearing orthotopic 4T1 breast tumors were randomly divided into four groups (n=5 in each group), namely, "PBS solution injection only (PBS) group", "PBS solution injection and laser irradiation (PBS+Laser) group", "PBS solution injection only with OPITBT-R NPs (OPITBT-R NPs) group", and "PBS solution injection with OPITBT-R NPs and laser irradiation (OPITBT-RNPs+Laser) group".

[0133] Control group: For the "PBS" and "OPITBT-R NPs" groups, mice were intravenously injected with 200 μL of PBS solution or OPITBT-R NPs in PBS solution (1 mg / mL), respectively, and no laser irradiation was performed. For the "PBS+L" group, 24 hours after intravenous injection of 200 μL PBS solution (this is the optimal enrichment time of OPITBT-R NPs in the body), the tumor site was irradiated with 808 nm laser (0.8 W / cm 2 ) for 5 minutes.

[0134] Experimental group: For the “OPITBT-R NPs+L” group, 24 hours after intravenous injection of 200 μL of OPITBT-R NPs in PBS (1 mg / mL), the tumor site was irradiated with 808 nm laser (0.8 W / cm 2 ) for 5 minutes. After the different treatments, the mice were cultured and observed for two weeks, and the weight and tumor volume of the mice were recorded every two days. The tumor size was measured with a vernier caliper, and the tumor volume (V) was calculated according to the following formula: V = (length × width 2 ) / 2. The relative tumor volume was calculated by the formula V / V0, where V0 was the initial tumor volume. After 14 days of different treatments, all tumors and major organs (heart, liver, spleen, lungs, and kidneys) of mice in each group were collected, fixed overnight with 4% (v / v) formaldehyde solution, embedded in paraffin, and sliced ​​to 5 μm thickness. Subsequently, the tumor sections of the four groups were stained with H&E, CD31, Ki67, and TUNEL, and histopathological evaluation was performed using an inverted optical microscope. The phototherapy results of tumor tissues are listed in Figures 16 to 18 shown. Fig.16 OPITBT-R NPs were used as phototherapy agents after single laser irradiation (808 nm, 0.8 W / cm 2 ) Schematic diagram of the relative tumor volume changes in mice after treatment and in the control group. Fig.17 This is a schematic diagram of tumor tissue photos of the treatment group and the control group after 14 days of treatment with nanoparticles OPITBT-R NPs as phototherapy agents. Fig.16 , 17 Explanation: Through 0.8W / cm 2 After a single irradiation of 808 nm laser for 5 minutes, the nanoparticles OPITBT-R NPs could achieve efficient ablation of tumor tissue with no recurrence within two weeks. Fig.18 This is a schematic diagram of the physiological changes in tumor tissue in the treatment group and the control group after 14 days of treatment with OPITBT-R NPs as a phototherapy agent. Fig.18 Explanation: Through 0.8W / cm 2 After a single irradiation of 808nm laser for 5 minutes, the nanoparticles OPITBT-R NPs effectively destroyed the tumor tissue and inhibited the new blood vessels. The above results all indicate that the nanoparticles OPITBT-R NPs can be used as phototherapy agents to achieve near-infrared second-zone fluorescence-photoacoustic-photothermal imaging-guided photothermal-photodynamic therapy for in situ breast cancer.

[0135] Embodiment 14

[0136] Biosafety testing of OPITBT-R NPs

[0137] The weight changes of mice were recorded every day during the 14-day treatment. In addition, H&E staining was performed on the sections of major organs to evaluate the biosafety. The biosafety test results of nanoparticles OPITBT-R NPs are shown in Fig.19 , 20 As shown, Fig.19 This is a schematic diagram of the weight changes of mice in the treatment group and the control group during 14 days of treatment with OPITBT-R NPs as a phototherapy agent. There was no significant difference in the weight of mice between the treatment group and the control group, proving that OPITBT-R NPs have no significant effect on mouse growth. Fig. 20 This is a schematic diagram of the physiological changes in the main organ tissues (heart, liver, spleen, lung, and kidney) of the treatment group and the control group after 14 days of treatment with OPITBT-R NPs as a phototherapy agent. There was no significant difference in the morphology of the main organ tissues between the treatment group and the control group, proving that the OPITBT-R NPs nanoparticles had no significant effect on the main organ tissues of mice. The above results all prove that the OPITBT-R NPs nanoparticles have good biosafety as a phototherapy agent.

[0138] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A benzobisthiadiazole derivative, characterized in that: The general structural formula is shown below: The π bridge is selected from one of the following structures: n is selected from 0 to 10; The structure of the electron donor is shown below: R1 is selected from hydrogen, C1-C20 alkyl, and C1-C20 alkoxy.

2. The benzobisthiadiazole derivative according to claim 1, characterized in that The structure of the electron donor is selected from one of the following structures 3. The benzobisthiadiazole derivative according to claim 2, characterized in that: The structure of the benzobisthiadiazole derivative is selected from one of the following structures:

4. A water-soluble nanoparticle, characterized in that: The invention is prepared from the benzobithiadiazole derivative according to any one of claims 1 to 3 and an amphiphilic polymer, wherein the amphiphilic polymer is selected from at least one of methoxypolyethylene glycol 2000-distearoylphosphatidylethanolamine and distearoylphosphatidylethanolamine-polyethylene glycol 2000-integrin targeting cyclic peptide.

5. The water-soluble nanoparticles according to claim 4, characterized in that: The preparation method of the water-soluble nanoparticles comprises the following steps: The benzobisthiadiazole derivative and the amphiphilic polymer in a mass ratio of 1:2 to 50 are ultrasonically dissolved in tetrahydrofuran, the mixture is quickly injected into water, and violently ultrasonicated in the water for at least 2 minutes; the mixed solution is dialyzed in deionized water for 1 to 24 hours to obtain the water-soluble nanoparticles.

6. Use of the benzobisthiadiazole derivative according to any one of claims 1 to 3 in the preparation of a multimodal photodiagnostic agent.

7. Use of the water-soluble nanoparticles according to claim 4 or 5 in the preparation of multimodal photodiagnostic agents.

8. Use of the benzobisthiadiazole derivative according to any one of claims 1 to 3 in the preparation of a drug for treating in situ breast cancer.

9. Use of the water-soluble nanoparticles according to claim 4 or 5 in preparing a drug for treating in situ breast cancer.

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