Dicationic AIE photosensitive dye based on non-conjugated N-methyl structure as well as synthesis method and application of dicationic AIE photosensitive dye

Abstract

The invention discloses a dicationic AIE photosensitive dye based on a non-conjugated N-methyl structure, and a synthesis method and application thereof. The photosensitive dye has a structure as shown in a general formula I. The invention further discloses a preparation method of the dicationic AIE photosensitive dye. According to the dicationic AIE photosensitive dye, aromatic compounds are connected in series with N methyl sites of indole and derivatives thereof, meanwhile, the aromatic compounds are coupled with AIE functional groups through a Knoevenagel condensation reaction, the quaternized dicationic characteristic can be achieved in one step, the excited state energy release process is effectively regulated and controlled, and aggregation-induced quenching is prevented. Meanwhile, the photosensitive dye has tunable absorption and emission spectrums, high photosensitization efficiency and high photo-thermal conversion efficiency in a near-infrared region. The nano-material has excellent tumor cell killing ability under near-infrared light irradiation, and has a good application prospect in the fields of biological imaging, preparation of biological optical diagnosis and treatment preparations and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of fine chemical organic dyes, and in particular to a class of dual-cationic AIE photosensitizing dyes based on non-conjugated N-methyl structures, their synthesis methods and applications. Technical Background

[0002] Phototherapy includes photodynamic therapy (PDT) and photothermal therapy (PTT), which refers to a new type of treatment method in which the excited states generated by photosensitizing dyes under light irradiation generate reactive oxygen species through intersystem crossing and heat through internal conversion, respectively, for treating diseases.

[0003] Although the photosensitizing dyes for PTT have strong light absorption ability in the near-infrared region, the activation of heat shock proteins induced during a single PTT process will greatly reduce the treatment effect. In addition, the high concentration (exceeding 0.2 mM) and high light dose (exceeding 1.0 W / cm2) of PTT may cause biological toxicity to surrounding normal tissues during the treatment process, limiting its clinical application. In contrast, the cytotoxic reactive oxygen species generated by PDT can effectively kill diseased tissues. With its characteristics of low concentration and low light dose, it can solve the above problems of PTT and improve the treatment effect and safety. At the same time, the characteristic that the PTT process does not require media such as oxygen also overcomes the deficiency of oxygen dependence in PDT. The advantages and disadvantages of the two treatment methods are complementary. Therefore, PDT and PTT combined treatment photosensitizing dyes can effectively improve the treatment effect of diseases, and are particularly suitable for anti-tumor and antibacterial applications.

[0004] However, in order to achieve an ideal treatment effect, the photosensitizing dyes for phototherapy need to simultaneously have a high reactive oxygen species production rate and a high photothermal conversion efficiency. Existing preparation strategies include encapsulation of various photosensitizing dyes, fluorescence resonance energy transfer, rotor excited state regulation, etc. Although attempts have been made to improve these properties, they generally face problems such as complex preparation processes and low energy utilization efficiency, resulting in the performance of such photosensitizing dyes for phototherapy not generally reaching the expected level.

[0005] Studies have shown that dicationic cyanine dyes exhibit better stability, water solubility, and tumor-specific targeting ability. In particular, they have unique advantages in reducing the energy gap between the excited state and the triplet state and accelerating the intersystem crossing rate, which can effectively improve the photodynamic therapy effect. In addition, aggregation-induced emission luminogens (AIEgens) have highly twisted molecular conformations and abundant rotor groups, showing weak fluorescence in dilute solutions and bright fluorescence in the aggregated state. According to literature reports, in certain specific structures, the rotor motion of AIEgens is restricted in the aggregated state, endowing the photodiagnostic materials with AIE properties (promoting radiative transition), and at the same time can reduce the singlet-to-triplet energy gap, which is beneficial to promoting photodynamic therapy. In addition, AIEgens with twisted molecular conformations can prevent excessive intermolecular π-π stacking, and by rotating the rotor, the excited state energy is consumed to enhance photothermal therapy.

[0006] However, the current technology still does not provide an ideal solution that can fully utilize these characteristics to achieve the preparation of photosensitizing dyes for high-performance combined photothermal and photodynamic therapy. Summary of the Invention

[0007] To prepare a photosensitizing dye for phototherapy that simultaneously has a high reactive oxygen species yield and a high photothermal conversion efficiency, the present invention discloses a dicationic AIE-based photosensitizing dye based on a non-conjugated N-methyl structure. This type of photosensitizing dye simultaneously has dicationic characteristics, AIE characteristics, photosensitization ability, and photothermal conversion ability, and has great application prospects in the fields of fine chemicals and life sciences, especially in the use of photosensitizing dyes for fluorescence imaging-guided phototherapy. On this basis, the present invention proposes a design strategy, that is, using a dicationic indole dye derivative connected by a non-conjugated N-methyl site as the parent molecule (receptor molecule), conjugating an AIE group, and designing and synthesizing a series of novel dicationic AIE-based photosensitizing dyes by using intramolecular conjugation effects, push-pull electron effects, molecular rotor effects, etc., so that they simultaneously have multiple functions such as good stability, high reactive oxygen species yield and photothermal conversion efficiency, and excellent antitumor photodynamic therapy effect.

[0008] To achieve the above object, the present invention provides a class of dicationic AIE-based photosensitizing dyes based on a non-conjugated N-methyl structure, having the structure shown in the following general formula 1:

[0009]

[0010] In general formula I, M is selected from any one of iodine, chlorine, bromine, perchlorate ion, hexafluoroborate ion, tetraphenylborate ion, and tetrakis(pentafluorophenyl)borate ion;

[0011] Y is selected from any one of dimethyl carbon, oxygen atom, sulfur atom, and selenium atom;

[0012] A is selected from any one of the groups represented by Formulae A-1 to A-9:

[0013]

[0014] wherein R2, R2`, R3, R4, and R4` are each independently selected from any one of hydrogen, fluorine, chlorine, bromine, methyl, ethyl, long-chain alkyl, and long-chain alkoxy;

[0015] Formula B is selected from any one of Formulae B-1 to B-3;

[0016]

[0017] wherein R5 is selected from any one of hydrogen, fluorine, chlorine, bromine, carboxyl group, and sulfonic acid group;

[0018] Formula C is selected from any one of Formulae C-1 to C-7;

[0019]

[0020] wherein X is selected from any one of a nitrogen atom, an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom; n2 is selected from any one of 1, 2, and 3;

[0021] D is selected from any one of Formulae D-1 to D-4;

[0022]

[0023] wherein R7, R7`, R8, R8`, and R8`` are each independently selected from any one of a hydrogen atom, methyl, ethyl, a C3-C20 straight-chain or branched-chain alkyl, and a C3-C20 straight-chain or branched-chain alkoxy.

[0024] For the above-mentioned technical solution, further preferably: the dye is selected from one of the compounds represented by the following Formulae 1-1 to 1-15:

[0025]

[0026]

[0027] For the above-mentioned technical solution, further preferably: the absorption wavelength of the dicationic AIE photosensitizing dye in the near-infrared region is 650 - 800 nm, and the emission wavelength is 800 - 950 nm. More preferably, the absorption peak is located at 700 - 750 nm, and the emission peak is located at 850 - 900 nm; in the most preferred Example 1 of the present invention, the absorption peak is located at 720 nm, and the emission peak is located at 870 nm.

[0028] On the other hand, the present invention is to protect the synthesis method of the dyes described above, including the Knoevenagel condensation reaction of the general formula 2 and the general formula 3 in an organic base and a polar solvent environment as follows:

[0029]

[0030] For the technical solutions described above, it is further preferred that the molar ratio of the compounds of the general formula 2 and the general formula 3 is 1:2-5; more preferably 1:2-4; most preferably 1:2.5-3.

[0031] For the technical solutions described above, it is further preferred that the organic base is selected from at least one of triethylamine, pyridine, N,N-diisopropylethylamine, and piperidine.

[0032] For the technical solutions described above, it is further preferred that the molar ratio of the compound of the general formula 3 to the organic base is 1:0.2-0.8; more preferably 1:0.3-0.7; most preferably 1:0.3-0.6.

[0033] For the technical solutions described above, it is further preferred that the polar solvent is selected from at least one of formamide, ethanol, methanol, N,N-dimethylformamide, and dimethyl sulfoxide.

[0034] For the technical solutions described above, it is further preferred that this method further includes the synthesis method of the general formula 2, including the step of reacting the 1N and 2N compounds in a molar ratio of 2-5:1 in the solvent I; the molar ratio of the 1N and 2N compounds is more preferably 2-4:1; most preferably 2.5-3:1; the solvent I is selected from at least one of toluene, acetonitrile, and methanol.

[0035] In the last aspect of the present invention, it also protects the applications of a class of dual-cationic AIE-based photosensitive dyes based on non-conjugated N-methyl structures in the fields such as bioimaging and the preparation of bio-optical diagnosis and treatment agents. Specific applications include but are not limited to protein labeling, bioimaging, and bio-optical diagnosis and treatment.

[0036] Furthermore, such photosensitive dyes are particularly suitable for anti-tumor photodynamic therapy, photothermal therapy, and combined therapy, etc. Further, for normoxic and hypoxic photodynamic anti-tumor therapy, photothermal anti-tumor therapy, and combined therapy, the dual-cationic AIE-based photosensitive dyes based on non-conjugated N-methyl structures have high-efficiency organelle targeting ability, and have strong reactive oxygen generation ability and photothermal conversion efficiency under near-infrared light irradiation, making them ideal anti-tumor phototherapy tools.

[0037] Furthermore, the application scenarios of such photosensitive dyes include but are not limited to:

[0038] Anti-tumor photodynamic therapy: Photosensitizing dyes can generate reactive oxygen species under light irradiation, effectively killing tumor cells.

[0039] Photothermal therapy: Photosensitizing dyes can be efficiently converted into heat under near-infrared light irradiation for destroying tumor tissues.

[0040] Combined therapy: Combining the advantages of photodynamic therapy and photothermal therapy to improve the therapeutic effect, especially suitable for combating drug resistance and deep tumors.

[0041] Bioimaging: Due to their strong absorption and emission characteristics in the near-infrared region, such photosensitizing dyes can be used for high-resolution fluorescence imaging to assist in diagnosis and monitor the treatment process.

[0042] The "diagnosis" and "treatment" mentioned above do not refer to the technical field of "methods for diagnosing and treating diseases", but rather refer to the related technologies and applications of "preparing preparations" in such fields, that is, related to the development and preparation methods of preparations for disease diagnosis and treatment.

[0043] In summary, the present invention has the following beneficial effects:

[0044] 1. Based on the connection at the N-methyl position of the dicationic photosensitizing dye with a non-conjugated N-methyl structure, the designed and synthesized dicationic photosensitizing dye with AIE characteristics has strong absorption and emission spectra in the near-infrared region (the main absorption spectrum is located at 650 nm - 800 nm, and the main emission spectrum is located at 800 nm - 950 nm);

[0045] 2. Due to the dicationic structure, the prepared dicationic photosensitizing dye based on the non-conjugated N-methyl structure has a better charge separation effect. At the same time, the AIE characteristic group endows the photosensitizing dye with aggregation-induced emission characteristics, effectively solving the problem of aggregation-induced quenching of the photosensitizing dye; it can be excited by near-infrared light to generate reactive oxygen species and heat for efficiently killing tumor cells.

[0046] 3. After testing, the dyes of the present application have great changes in performance such as long-wavelength absorption and emission, reactive oxygen species yield, and photothermal conversion compared with traditional D-π-A type photosensitizing dyes. Under light irradiation, they have excellent cell killing ability. On the contrary, in the absence of light, such dyes have good biocompatibility. In the examples of the present application, using photosensitizing dyes with different concentrations still showed more than 85% cell viability after culturing MCF-7 cells for 48 h, indicating that they will not cause toxic side effects to cells within the working concentration range. Description of the Drawings

[0047] Figure 1 It is the high-resolution mass spectrum of the photosensitizing dye FG-2pBECy disclosed by the present invention;

[0048] Figure 2 High-resolution mass spectrum of the photosensitive dye FG-2pBTCy disclosed in the present invention;

[0049] Figure 3 High-resolution mass spectrum of the photosensitive dye BTCy of the comparative example disclosed;

[0050] Figure 4 Absorption and emission spectra of the photosensitive dyes FG-2pBECy, FG-2pBTCy disclosed in the present invention and the comparative example BTCy in different solvents (methylene chloride, methanol, dimethyl sulfoxide, water);

[0051] Figure 5 Emission spectra diagram of the AIE characteristics of the photosensitive dyes FG-2pBECy, FG-2pBTCy disclosed in the present invention and the comparative example BTCy in a toluene / dimethyl sulfoxide mixed solvent;

[0052] Figure 6 Ability of the photosensitive dyes FG-2pBECy, FG-2pBTCy disclosed in the present invention and the comparative example BTCy to generate reactive oxygen species in the reactive oxygen species detection reagent ABDA;

[0053] Figure 7 Photothermal conversion efficiency diagram of the photosensitive dyes FG-2pBECy and FG-2pBTCy disclosed in the present invention under laser irradiation;

[0054] Figure 8 Confocal fluorescence imaging images of the targeted localization of the photosensitive dyes FG-2pBECy and FG-2pBTCy disclosed in the present invention in organelles (corresponding to lysosomes and mitochondria respectively) in MCF-7 cells;

[0055] Figure 9 MTT experiment diagram of the photosensitive dyes FG-2pBECy, FG-2pBTCy disclosed in the present invention and the comparative example BTCy in MCF-7 cells. Detailed implementation manners

[0056] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are one embodiment of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0057] Unless otherwise specified, various raw materials used in the specific implementation manners of the present invention can be obtained commercially, or can be prepared by methods known to those skilled in the art or by principles known in the art through methods disclosed in the prior art.

[0058] The following is a detailed description of a class of dual-cationic AIE photosensitive dyes based on non-conjugated N-methyl structure represented by general formula I in combination with specific embodiments.

[0059] To demonstrate the unique properties of the dual-cationic AIE photosensitive dyes based on non-conjugated N-methyl structure of the present invention, the present invention first introduces an AIE-type D-π-A photosensitive dye containing only a single cation as a comparative example, named BTCy. The theoretical value of the high-resolution mass spectrum of this comparative example photosensitive dye is M[C38H37N2S]+ = 553.2672, and the actual measured value is 553.2681 (see Figure 3 ). The specific structure of BTCy is as follows:

[0060]

[0061] Example 1

[0062] The synthesis process involved in Example 1 is as follows:

[0063]

[0064] For the AIE-type dual-cation photosensitive dye based on non-conjugated N-methyl structure, M is selected from bromine, and Y is selected from dimethyl;

[0065] A is selected from B is selected from C is selected from D is selected from

[0066] Its synthesis method includes the following steps:

[0067] (1) Synthesis of general formula 2 (BCy)

[0068] 2,3,3-Trimethyl-3H-indole (named YD) (1.99 g, 12.5 mmol) and A-2Br (1,4-bis(bromomethyl)benzene, named p-2Br) (1.32 g, 5 mmol) were refluxed overnight under nitrogen protection in 25 mL of acetonitrile. The reaction was stopped, and after the reaction returned to room temperature, it was added to an excess of ether, and the compound BCy was prepared by recrystallization. This compound was used directly in the next step without purification.

[0069] (2) Synthesis of compound TE

[0070] 5-Bromo-2-(3,4-ethenedioxythiophene)carbaldehyde (3.6 mmol) and alkyltriphenylamine borate (3.0 mmol) were dissolved in tetrahydrofuran, potassium carbonate aqueous solution and the catalyst tetrakis(triphenylphosphine)palladium were added; under nitrogen protection, it was refluxed for 12 h, and a yellow product (named TE) was obtained by column chromatography purification.

[0071] (3) Synthesis of Compound FG-2pEBCy

[0072] Ethanol, DMF (10 ml, v:v = 1:1), piperidine (0.1 ml), and pyridine (0.1 mL) were added to a dichloromethane solution containing TE (3.0 mmol) and 2p (1 mmol) respectively. The reaction was carried out at 90 °C for 3 h under nitrogen protection. The solution was poured into tert-butyl methyl ether (250 ml), and a blue-black solid was obtained after filtration. The crude product was purified by silica gel column chromatography using dichloromethane / methanol (v / v, 20 / 1) as the eluent, and the product was a blue-black solid. Taking FG-2pEBCy as an example, its high-resolution mass spectrum is as follows Figure 1 The theoretical value of its high-resolution mass spectrum is M[C 84 H 76 N4O4S2] 2+ = 634.2649, and the actual measured value is 634.2643. See Figure 1 .

[0073] Example 2

[0074] The difference from Example 1 is only that 5-(4-(di-p-tolylamino)phenyl)thiophene-2-carbaldehyde, named TT, is used to replace TE.

[0075] The product prepared by the method of Example 2 of this application is named FG-2pTBcy, and the yield is 26.3%. The theoretical value of its high-resolution mass spectrum is M[C 80 H 72 N4S2] 2+ = 576.2594, and the actual measured value is 576.2622. See Figure 2 .

[0076] 1-2 Photophysical Property Test

[0077] After drying FG-2pBECy and FG-2pBTCy, they were accurately weighed and dissolved in dimethyl sulfoxide to prepare a DMSO dye mother liquor with a concentration of 2.0 mM. Then these solutions were placed in 1.50 mL brown sample bottles and stored in the refrigerator for future use. During the test, 20 μL of the FG-2pBECy and FG-2pBTcy dye mother liquors were dissolved in 2.00 mL of different solvents, and the absorption spectra of the dyes were measured at room temperature using a UV-visible spectrophotometer, and the fluorescence spectra of the dyes were measured by fluorescence method. The relevant results are shown in Figure 4 .

[0078] From Figure 3 , Figure 4It can be seen that the maximum absorption of FG-2pBECy and FG-2pBTcy is located in the near-infrared region of 600-700 nm, and the fluorescence emission spectra are located in the range of 850-950 nm, both within the bio-diagnosis and treatment window. For the comparative molecule BTCy, its absorption spectrum is only in the range of 500-600 nm, and the emission spectrum is located in the range of 650-900 nm. The near-infrared absorption spectrum within the bio-diagnosis and treatment window is conducive to the penetration of light and the effective utilization of energy. Therefore, the AIE-type dicationic photosensitizing dyes designed and synthesized in this patent can be effectively applied to tissue imaging and tumor treatment in near-infrared region scenarios.

[0079] 1-3 AIE property tests

[0080] When in the aggregated state, the intramolecular rotation of AIE molecules is inhibited, and the energy changes from thermal radiative transition to fluorescence-enhanced non-radiative transition. A toluene / dimethyl sulfoxide mixed solvent system was used to evaluate the AIE properties of FG-2pBECy and FG-2pBTcy. As the volume fraction of toluene increased (0% - 80%), the changes in the fluorescence intensities of FG-2pBECy, FG-2pBTcy, and the comparative BTCy in the mixed solvent system were measured. The test results are shown in Figure 5 .

[0081] As Figure 5 shown, as the volume fraction of toluene increased, the fluorescence intensities of FG-2pBCy and FG-2pBECy in the mixed system increased significantly. When the volume fraction of toluene was 90%, the fluorescence intensities of FG-2pBECy and FG-2pBTCy reached their maximum values. However, the change in the fluorescence intensity of the comparative BTCy was not as obvious as that of the two AIE-type dicationic photosensitizing dyes. This shows that FG-2pBECy and FG-2pBTCy have better AIE properties and effectively solve the problem of aggregation-induced quenching of photosensitizing dyes.

[0082] 1-4 Singlet oxygen yield and photothermal conversion efficiency tests

[0083] 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) was used as a singlet oxygen scavenger. ABDA can react with singlet oxygen in aqueous solution and be oxidized to anthracene endoperoxide, and the conjugated system is destroyed, resulting in a decrease in the absorbance of its absorption peak at around 378 nm. A 660 nm, 5 mW cm -2 laser was used to irradiate and test the singlet oxygen quantum yields of the photosensitizing dyes FG-2pBECy and FG-2pBECy, as well as the comparative BTCy. First, 3.00 mL of pure water was added to a sealed quartz test tube, an appropriate amount of ABDA stock solution was added, and the mixture was stirred evenly to make the absorbance at 378 nm reach about 1.0. Then, the dye stock solution was added to make the absorbance of the dye molecules at 660 nm between 0.3 and 0.4. The test results are shown inFigure 6 .

[0084] The Fourier transform infrared camera was used to perform photothermal heating imaging on the photosensitive dyes FG-2pBECy and FG-2pBECy. A 660 nm laser (300 mW / cm 2 , 5 min) was used to irradiate the solutions containing FG-2pBECy and FG-2pBECy respectively, and an infrared thermal imager was used to monitor the temperature. The sample concentration was 10 μM. The photothermal conversion efficiency of the compound was calculated by the following formula:

[0085]

[0086] In the formula, h represents the heat transfer coefficient, s represents the surface area of the container, QDis represents the heat dissipated by the laser irradiating the container or the solvent, I represents the laser intensity, and A represents the absorbance of the test molecule at 660 nm.

[0087]

[0088] m represents the mass of the solution containing the molecule to be measured, C represents the specific heat capacity of the solution, and τs represents the time correlation coefficient.

[0089] t = -τ s lnθ

[0090] Θ is a dimensionless parameter representing the driving force of temperature.

[0091]

[0092] T Max and T surr are the maximum value of the steady-state temperature and the temperature of the environment respectively.

[0093] As Figure 6 shown, with short-time laser irradiation, the absorbance of ABDA decreased significantly. Compared with the control group containing only ABDA, the absorbance of ABDA hardly decreased under laser irradiation. This indicates that the photosensitive dyes FG-2pBECy and FG-2pBTCy can generate singlet oxygen. At the same time, the rate of decrease in the absorbance of ABDA in the control group BTCy under laser irradiation was significantly lower than that of the two AIE-type dicationic photosensitive dyes. Therefore, the AIE-type dicationic photosensitive dye prepared in this application can be effectively excited by near-infrared light to generate singlet oxygen and can be used for efficient anti-tumor therapy.

[0094] As Figure 7As shown, with the extension of the illumination time, the solution temperature increased significantly. The calculated photothermal conversion efficiencies were 47.75% and 44.69% respectively. The high photothermal conversion efficiency further verified the high photothermal conversion ability of the photosensitizing dyes FG-2pBECy and FG-2pBTCy. Therefore, the AIE-type dicationic photosensitizing dyes prepared in this application can be excited by near-infrared light and generate heat through thermal radiation transitions for efficient anti-tumor therapy.

[0095] 1-5 Cell Uptake and Co-localization Experiments

[0096] MCF-7 cells were cultured in DMEM with 10% FBS. 2 μM of the photosensitizing dyes FG-2pBECy and FG-2pBTCy were respectively added to the culture medium containing MCF-7 cells, incubated at 37 °C, and then the uptake amount was judged by confocal imaging. The excitation wavelength of the photosensitizing dyes was 640 nm and the emission was 700 nm. The test results are shown in Figure 8 in.

[0097] The concentration of the photosensitizing dyes was 2 μM, and MTG (mitochondria) and LTG (lysosomes) were both 100 nM. First, 2 μM of the photosensitizing dyes FG-2pBECy and FG-2pBTCy were respectively added to the dishes containing MCF-7 cells and incubated for 4 hours, and then two 100 nM commercial dyes were respectively added to the cell culture dishes and incubated, and then laser confocal imaging was performed. The excitation wavelength of the photosensitizing dyes was 640 nm and the emission was 700 nm. The excitation wavelength of MTG was 488 nm and the acceptance band was 515 - 545 nm. It can be seen from Figure 8 that the photosensitizing dye FG-2pBECy can be well localized in the lysosomes of MCF-7 cells, and the photosensitizing dye FG-2pBTCy can be well localized in the mitochondria of MCF-7 cells.

[0098] 1-6 Photo-Dark Toxicity Experiments of Photosensitizing Dyes on MCF-7 Cells

[0099] The MCF-7 cells to be detected were digested with 0.25% trypsin and made into a cell suspension with DMEM culture medium containing 10% fetal bovine serum, and inoculated into a 96-well culture plate at 10 3 ~10 4 cells per well, with a volume of 100 μL per well; the culture plate was transferred to a cell culture incubator and incubated at 37 °C, 5% CO2 and saturated humidity for 24 hours, and then different concentrations of the photosensitizing dyes FG-2pBECy and FG-2pBTCy and the control molecule BTCy were added respectively and cultured for another 4 hours; then 660 nm, 50 mW / cm 2Irradiate each well with a near-infrared light source. After the irradiation is completed, continue to place the 96-well plate in the incubator for 24 h. Add 20 μL of MTT solution (5 mg / mL) to each well, incubate for 4 hours, terminate the culture, and carefully aspirate the culture supernatant in the well. Then, add 100 μL of DMSO to each well and shake for 10 minutes to fully dissolve the crystals. Measure the absorbance at 490 nm of each well on an enzyme-linked immunosorbent assay (ELISA) reader, and calculate the cell survival rate: absorbance of the experimental group / absorbance value of the control group × 100%. See the test results in Figure 9 .

[0100] From Figure 9 it can be seen that the dual-cationic AIE-based photosensitizing dyes FG-2pBECy and FG-2pBTCy prepared in this application, which are based on the non-conjugated N-methyl structure, both have excellent tumor cell killing ability under light irradiation conditions. Under dark conditions, after culturing MCF-7 cells with different concentrations of photosensitizing dyes FG-2pBECy and FG-2pBTCy for 48 h, more than 85% cell viability was still shown, indicating that this type of photosensitizing dye does not produce toxic side effects on cells within the working concentration range and has good biocompatibility. In contrast, the comparative example BTCy showed poor photocytotoxicity under the same conditions.

[0101] Based on the above content, this application is based on the diversity of the non-conjugated N-methyl site structure modification of dual-cationic photosensitizing dyes, combined with the high energy utilization efficiency and the characteristics of promoting radiative transition of AIE-type photosensitizing molecular fragments. An aromatic compound is used as a linker arm and an AIE group is used as a donor group, and a dual-cationic parent structure linked by an aromatic compound is used as an acceptor group. By utilizing the strong electron push-pull effect between the dual-cationic structure and the AIE structure, a series of novel AIE-based photosensitizing dyes based on dual-cationic structures are designed, enabling them to have multiple functions such as good stability, high photosensitization efficiency, combined therapy, and excellent anti-tumor phototherapy effect.

[0102] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A class of dicationic AIE photosensitive dyes based on non-conjugated N-methyl structures, having the structure shown in the following general formula 1: In general formula I, M is selected from any one of iodine, chlorine, bromine, perchlorate ion, hexafluoroborate ion, tetraphenylborate ion, and tetrakis(pentafluorophenyl)borate ion; Y is selected from any one of dimethylcarbon, oxygen atom, sulfur atom, and selenium atom; A is selected from any one of the groups described in formulas A-1 to A-9: Among them, R2, R2`, R3, R4, and R4` are each independently selected from any one of hydrogen, fluorine, chlorine, bromine, methyl, ethyl, long-chain alkyl, and long-chain alkoxy; Formula B is selected from any one of formulas B-1 to B-3; wherein, R5 is selected from any one of hydrogen, fluorine, chlorine, bromine, carboxyl group, and sulfonic acid group; Formula C is selected from any one of formulas C-1 to C-7; wherein, X is selected from any one of nitrogen atom, oxygen atom, sulfur atom, selenium atom, and tellurium atom; n2 is selected from any one of 1, 2, and 3; D is selected from any one of formulas D-1 to D-4; wherein, R7, R7`, R8, R8`, and R8`` are each independently selected from any one of hydrogen atom, methyl, ethyl, C3-C20 straight-chain or branched-chain alkyl, and C3-C20 straight-chain or branched-chain alkoxy.

2. The dye according to claim 1, characterized in that: Selected from one of the compounds shown in the following formulas 1-1 to 1-15:

3. The dye according to claim 1, wherein The absorption wavelength of the dicationic AIE photosensitive dye in the near-infrared region is 650-800 nm, and the emission wavelength is 800-950 nm.

4. The synthesis method of the dye according to claim 1, characterized in that, Including the Knoevenagel condensation reaction of general formula 2 and general formula 3 in an organic base and polar solvent environment, as follows:

5. The synthesis method according to claim 4, characterized in that, The molar ratio of the compounds of general formula 2 and general formula 3 is 1:2-5.

6. The synthesis method according to claim 4, characterized in that, The organic base is selected from at least one of triethylamine, pyridine, N,N-diisopropylethylamine, and piperidine.

7. The synthesis method according to claim 4, characterized in that, The molar ratio of the compound of general formula 3 to the organic base is 1:0.2-0.

8.

8. The synthesis method according to claim 4, characterized in that The polar solvent is selected from at least one of formamide, ethanol, methanol, N,N`-dimethylformamide, and dimethyl sulfoxide.

9. The synthesis method according to claim 4, characterized in that, It also includes a synthesis method of general formula 2, including the step of reacting 1N and 2N compounds in a molar ratio of 2-5:1 in solvent I; solvent I is selected from at least one of toluene, acetonitrile, and methanol.

10. Use of the class of dicationic AIE photosensitive dyes based on non-conjugated N-methyl structures described in claim 1 in bioimaging and in the field of preparing bio-optical diagnosis and treatment preparations.

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