Mitochondrial DNA-targeted 4-aminophenylpyrylium photosensitizers and methods of making and using the same

Abstract

The application discloses a kind of mitochondrial DNA targeted 4-amino benzopyran photosensitive dye and its preparation method and application, wherein the structure general formula of 4-amino benzopyran photosensitive dye is as follows: The preparation method of the 4-amino benzopyran photosensitive dye and its application in the preparation of mitochondrial DNA photosensitive imaging agent and mitochondrial DNA targeted tumor photodynamic therapy photosensitizer are also specifically disclosed.The photosensitive dye has excellent photosensitive activity and spectral feedback performance, which improves the in vivo tumor treatment efficacy.The 4-amino benzopyran photosensitive dye prepared by the application has low biological toxicity and high phototoxicity in in vivo tumor treatment, and the raw material is easy to obtain, the structure is simple, easy to prepare and easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of photosensitive dyes and photodynamic tumor therapy technology, specifically involving a class of mitochondrial DNA-targeting 4-aminobenzopyran photosensitive dyes, their preparation methods, and applications. Background Technology

[0002] Photodynamic therapy (PDT) is a novel treatment method based on photochemical reactions. Due to its high spatiotemporal selectivity, non-invasiveness, and negligible drug resistance, it has become a promising new cancer treatment. PDT primarily involves photosensitive dyes generating large amounts of reactive oxygen species (ROS) through energy (type II) and / or electron transfer (type I) under irradiation with a specific wavelength light source. This high oxidative activity induces apoptosis and necrosis of tumor cells. In this treatment process, the photosensitive dye is the most crucial factor in regulating the therapeutic effect, and its structural design and performance optimization are currently the focus of research. Many related photosensitive dyes have been developed and reported. However, existing photosensitive dyes still face the following limitations and challenges in clinical treatment: (1) low photosensitivity, resulting in insufficient tumor cell killing ability, severely limiting the therapeutic effect of PDT; (2) lack of spectral monitoring performance, making it impossible to monitor the treatment process in real time, leading to overtreatment / undertreatment and affecting the therapeutic effect. Therefore, it is urgent to construct novel photosensitive dyes that possess both high tumor cell killing ability and spectral detection performance for the treatment process, in order to maximize the therapeutic effect of tumor treatment.

[0003] In the study of photosensitive dyes, strategies such as introducing heavy atoms, regulating intramolecular electron transfer, and addressing steric hindrance have been widely reported for modulating the intersystem crossing efficiency (ISC) of photosensitive dyes, thereby effectively improving their photosensitivity. Building on this, researchers have also focused on the spectral detection performance of photosensitive dyes, developing target-based photosensitive dyes using viscosity and pH as biomarkers. These dyes, while initiating photodynamic therapy (PDT), allow for real-time monitoring of corresponding biomarkers, enabling real-time feedback and regulation of the PDT process through changes in spectral signals, maximizing therapeutic efficacy. However, target-based photosensitive dyes remain extremely scarce, necessitating the development of novel, high-performance target-based photosensitive dyes. Mitochondrial DNA (mtDNA), as the unique genetic material within mitochondria, is highly susceptible to damage due to its unique structure and environment, leading to mitochondrial dysfunction and inducing apoptosis. Furthermore, studies have shown that reactive oxygen species can damage mtDNA, accelerating apoptosis, and the degree of mtDNA damage can provide real-time feedback on the apoptosis process. Therefore, constructing corresponding photosensitive dyes targeting mtDNA can not only enhance tumor-killing efficacy by damaging mtDNA, but also optimize the photochemical reaction (PDT) process based on real-time spectral monitoring of the degree of mtDNA damage, thus achieving highly efficient clinical cancer treatment. Currently, the design of mtDNA-targeted photosensitive dyes remains scarce, and their design principles are unclear, significantly increasing the difficulty of designing such dyes. Furthermore, based on the principle of dye fluorescence emission and photochemical reaction, these two processes are in competition, making the synergistic regulation of photosensitive dye spectral monitoring performance and photosensitivity a major challenge in current research. Therefore, designing and synthesizing photosensitive dyes targeting mtDNA that possess both high photosensitivity and spectral detection performance to improve the therapeutic efficacy of clinical cancer treatment remains a significant challenge, and there are currently no relevant reports in this area. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a class of mitochondrial DNA-targeting 4-aminobenzopyran-based photosensitive dyes and their preparation method. The photosensitive dyes prepared by this method target mtDNA and can bind to mitochondrial DNA with high specificity in living cells, emitting a strong fluorescent signal. The fluorescent signal can be used to track the content of mtDNA in cells, and can then be used to prepare mtDNA photosensitive imaging agents and mtDNA-targeting tumor photodynamic therapy photosensitizers.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A class of mitochondrial DNA-targeting 4-aminobenzopyran photosensitive dyes, the general structural formula of which is shown in Formula I:

[0007]

[0008] In Formula I, R1 and R2 are either -H or one of the following groups:

[0009]

[0010] Where m is -H, -Cl, -Br or -I, and x is -CH3, -OH, -NH2, -COOH, -SO3 - -Cl, -Br or -I, y is O, S or Se, and n is an integer between 0 and 4;

[0011] In Equation I, K and L represent -CO- and -Cp=CH- (CH=CH), respectively. n -or -Cp=CH-(CH=CH) n -CH = Cp-;

[0012] Where p is -CH3, -CN, -Br, -Cl, -H, -OH, -NH2, -(CH2)nNH2, or -SO3 - n is an integer between 0 and 8.

[0013] A class of mitochondrial DNA-targeting 4-aminobenzopyran photosensitive dyes includes compounds with the following structures:

[0014]

[0015] The preparation method of the mitochondrial DNA-targeting 4-aminobenzopyran photosensitive dye of the present invention comprises the following specific preparation steps:

[0016] Step S1: Under acidic conditions, salicylamide, acetone, and acetic anhydride are first added to the reaction solvent, then an oxidizing agent is added, and an oxidation reaction is carried out at 0-100℃ to obtain compound A. The structural formula of compound A is:

[0017]

[0018] The oxidant is one or more of potassium permanganate, hydrogen peroxide, sodium hypochlorite, Vilsmeier reagent, potassium dichromate, sodium dichromate, nitric acid, peracetic acid, or chromic acid.

[0019] Step S2: Compound A obtained in step S1 is reacted with 5-iodo-1,2,3,3-tetramethyl-3H-indolon iodide or 1,2,3,3-tetramethyl-3H-indolon iodide by heating and reflux to prepare compounds shown in Formulas 1-1 to 1-4, which are mitochondrial DNA-targeting 4-aminobenzopyran photosensitive dyes.

[0020] Further, the molar ratio of salicylamide, acetone and acetic anhydride in step S1 is 1:1:1 to 1:2:2.

[0021] Further, the reaction solvent in step S1 is one or more of dichloromethane, ethanol, methanol, acetone, 1,4-dioxane, glycerol, ethyl acetate, acetic acid, sulfuric acid, acetic anhydride, aqueous sodium hydroxide solution, or N,N-dimethylformamide.

[0022] Further, in step S2, the molar ratio of compound A to 5-iodo-1,2,3,3-tetramethyl-3H-indolium iodide or 1,2,3,3-tetramethyl-3H-indolium iodide is 1:0.5-1:4.

[0023] Further, the reaction solvent in step S2 is one or more of dichloromethane, ethanol, methanol, acetone, 1,4-dioxane, glycerol, ethyl acetate, acetic acid, sulfuric acid, piperidine, or N,N-dimethylformamide.

[0024] The application of the mitochondrial DNA-targeting 4-aminobenzopyran photosensitive dye described in this invention in the preparation of mitochondrial DNA photosensitive imaging agents.

[0025] The application of the mitochondrial DNA-targeting 4-aminobenzopyran-based photosensitive dye described in this invention in the preparation of mitochondrial DNA-targeting tumor photodynamic therapy photosensitizers.

[0026] The 4-aminobenzopyran-based photosensitive dyes described in this invention can bind highly specifically to mtDNA via small groove interaction, enabling specific quantification and real-time monitoring of mtDNA. Furthermore, these photosensitive dyes possess high photosensitivity, generating abundant ROS under corresponding wavelength laser irradiation to efficiently damage mtDNA and induce apoptosis and necrosis. Moreover, these photosensitive dyes exhibit good biocompatibility, allowing them to reflect mtDNA damage in real-time via spectral signals while initiating photodynamic therapy, thereby assessing the degree of apoptosis, regulating the treatment process, and improving the efficacy of cancer treatment.

[0027] The 4-aminobenzopyran-based photosensitive dyes described in this invention can initiate a photochemical reaction under light activation, generating a large amount of reactive oxygen species and initiating the photodynamic therapy process. Furthermore, these photosensitive dyes target mtDNA, binding highly and specifically to mitochondrial DNA within living cells and emitting a strong fluorescent signal to track the intracellular mtDNA content. The strong mitochondrial targeting ability of these photosensitive dyes allows them to rapidly damage mtDNA, enhancing their cytotoxicity. Simultaneously, changes in fluorescence signal reflect mitochondrial damage, providing real-time feedback on the progress of in vivo tumor treatment, thereby allowing for timely adjustments to the treatment plan to maximize the therapeutic effect on in vivo tumors. The 4-aminobenzopyran-based photosensitive dyes described in this invention also possess low biotoxicity, suitable water solubility, and good anti-interference ability.

[0028] This invention offers the following advantages and benefits: The photosensitive dye of this invention possesses a hemicyanine conjugated structure, exhibiting a strong binding capacity to mtDNA and enhancing its spectral feedback performance in assessing the degree of mtDNA damage. The photosensitive dye of this invention possesses a classic D-Π-A structure, enabling excellent photochemical reactions through intramolecular charge transfer, thus optimizing its photosensitivity. The photosensitive dye of this invention simultaneously possesses excellent photosensitivity and spectral feedback performance, improving its efficacy in in vivo tumor therapy. The photosensitive dye of this invention exhibits low biotoxicity and high phototoxicity in in vivo tumor therapy, and its raw materials are readily available, its structure is simple, it is easy to prepare, and it is easily industrialized. Attached Figure Description

[0029] Figure 1 These are the experimental results of the test on the responsiveness of photosensitive dye 1-1 to mtDNA.

[0030] Figure 2 These are the experimental results of the photosensitivity test of photosensitive dye 1-1.

[0031] Figure 3 These are experimental results of the photosensitive dye 1-1 imaging the recognition of mtDNA in living cells.

[0032] Figure 4 This is the result of a performance evaluation test of photosensitive dye 1-1 in generating ROS in living cells.

[0033] Figure 5 This is the result of an experiment evaluating the killing power of photosensitive dye 1-1 against tumor cells.

[0034] Figure 6 These are the experimental results of the test on the responsiveness of photosensitive dyes 1-2 to mtDNA.

[0035] Figure 7 These are the experimental results of the response ability test of photosensitive dyes 1-3 to mtDNA.

[0036] Figure 8 These are the experimental results of testing the responsiveness of photosensitive dyes 1-4 to mtDNA. Detailed Implementation

[0037] The following examples further illustrate the specific technical content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0038] Example 1

[0039] The photosensitive dye 1-1 was prepared using the following synthetic route:

[0040]

[0041] Synthesis of photosensitive dye 1-1:

[0042] 5.0 mmol of compound A and 3.0 mmol of 5-iodo-1,2,3,3-tetramethyl-3H-indolon iodide were added to a round-bottom flask containing 30.0 mL of N,N-dimethylformamide. After stirring and mixing thoroughly, 1.5 mL of trimethylchlorosilane was added. The mixture was stirred and heated under reflux for 5.0 h before being stopped. The mixture was poured into ice water, and a precipitate formed. The precipitate was obtained by filtration and the crude product was a purple solid. The crude product was separated by column chromatography to obtain a purple solid powder compound, which is the photosensitive dye 1-1, with a yield of 82%. 1 H NMR (600MHz, CDCl3) δ10.05(s,2H),9.64(s,1H),8.47(s,1H),8.01(s,2H),7.87(s,1H),7.74(d,J= 6.7Hz,1H),7.67(s,1H),7.28(d,J=6.6Hz,1H),6.94(s,1H),4.11(s,1H),3.64(s,3H),1.72(s,6H).

[0043] Assay for the responsiveness of photosensitive dye 1-1 to mtDNA:

[0044] The synthesized photosensitive dye 1-1 was added to PBS buffer (pH = 7.2) at a final concentration of 5.0 μM. Subsequently, mtDNA (0-10.16 μg / mL) was continuously added to the solution, and its UV absorption and fluorescence emission spectra were measured sequentially. The test results are as follows: Figure 1As shown, the results indicate that with increasing mtDNA content, its absorbance at 520 nm significantly decreased, and a slight red shift occurred. Simultaneously, its fluorescence signal at 601 nm significantly increased. This result demonstrates that the photosensitive dye 1-1 can bind to mtDNA, and its content changes can be fed back through fluorescence signals. Figure 1 The changes in UV absorption and fluorescence spectral signals after the photosensitive dye 1-1 bound to different amounts of mtDNA were observed. The instruments used were a Cintra 2020 (GBCS Scientific Equipment Pty Ltd) and a Fluoromax-4C-L (HORIBA).

[0045] Photosensitivity test of photosensitive dye 1-1:

[0046] The above-synthesized photosensitive dye 1-1 was used, with diphenylisobenzofuran (DPBF) as the ROS indicator. Photosensitive dye 1-1 was added to a 40.0 μM DPBF solution at a final concentration of 5.0 μM, and the absorbance change at 415 nm was measured under different illumination times. The test results are as follows: Figure 2 As shown, the results indicate that with increasing illumination time, its absorbance at 415 nm significantly decreases, and the decreasing trend is much greater than that produced by DPBF alone under illumination. This result suggests that the photosensitive dye 1-1 possesses photosensitizing activity, and under illumination, it can undergo a photochemical reaction to generate a large amount of reactive oxygen species, initiating the photodynamic therapy process. Figure 2 The light source used is a 525nm xenon lamp with a light power density of 23.0 mW / cm². 2 .

[0047] An experiment on the imaging of mtDNA recognition by photosensitive dye 1-1 in live cells:

[0048] Human breast cancer cells (MCF-7) were used as the research subject using the synthesized photosensitive dye 1-1. MCF-7 cells were pretreated with DNA digestion enzyme (100 U / mL), followed by incubation with 5.0 μM photosensitive dye 1-1 at 37℃ and 5 wt% / vol CO2 for 30 min. Cells were then washed with PBS for 5 min × 3, followed by the addition of cell culture medium and laser confocal imaging. Representative areas were selected and observed using a dry microscope (40×), repeated three times. The fluorescence acquisition wavelength was 550-650 nm, and the excitation wavelength was 515 nm. The experimental results are as follows: Figure 3 As shown in the figure, the fluorescence signal of photosensitive dye 1-1 mainly accumulates in the mitochondria, and its fluorescence signal is significantly reduced after pretreatment with DNA digesting enzymes. This result indicates that photosensitive dye 1-1 targets mtDNA and can identify changes in mtDNA content in living cells.

[0049] Performance evaluation of photosensitive dye 1-1 in generating ROS in living cells:

[0050] Using the synthesized photosensitive dye 1-1, human breast cancer cells (MCF-7) were used as the research object, and 2',7'-difluorescein diacetate (DCFH-DA) was used as the ROS indicator in live cells. Experimental group: MCF-7 cells were co-incubated with photosensitive dye 1-1 (3.0 μM) at 37℃ and 5 wt% / vol CO2 for 30 min, followed by incubation with DCFH-DA (10 μM) for another 20 min. Control group: MCF-7 cells were co-incubated with DCFH-DA (10 μM) only for 20 min. The cells were then irradiated under a 525 nm xenon lamp for 60 s, followed by laser confocal imaging. Representative areas were selected and observed using a dry microscope (40×), repeated three times. The fluorescence acquisition wavelength was 510-540 nm, and the excitation wavelength was 488 nm. The experimental results are as follows: Figure 4 As shown, under illumination, the experimental group cells exhibited a significant green fluorescence signal, while the fluorescence signal in the control group cells was negligible. This result indicates that, within living cells, the photosensitive dye 1-1 can generate a large amount of reactive oxygen species under illumination, initiating the photodynamic therapy process.

[0051] Assessment of the cytotoxic effect of photosensitive dye 1-1 on tumor cells:

[0052] Using the synthesized photosensitive dye 1-1, human breast cancer cells (MCF-7) were used as the research subject, and their tumor cell killing effect was evaluated using the MTT assay. MCF-7 cells were cultured at 5 × 10⁻⁶ cells / year. 4 100 μL of each sample was seeded into a 96-well plate at a density of 100 μL / well and incubated at 37°C for 24 h in a 5 wt% / vol CO2 incubator. Photosensitive dye was then added to the 96-well plate at a specific concentration gradient, with wells without added dye serving as blank control wells. The 96-well plate was incubated for another 1 h in a 5 wt% / vol CO2 incubator at 37°C, and then placed under a xenon lamp (525 nm xenon lamp, light power density 23 mW / cm²). 2 Irradiate for 10 min, then incubate the 96-well plate for 3 h. Next, add 20 μL (5 mg / mL) of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to each well and incubate for another 4 h to allow succinate dehydrogenase in the mitochondria of live cells to convert to formazan. Remove all solution from the 96-well plate, and add 150 μL of DMSO to each well to dissolve the formazan in the cells. Measure the absorbance at 490 nm using a microplate reader. The cell viability (%) is calculated using the formula (Cell viability (%) = (OD200%) / (OD200%). 实验孔 / OD空白孔 The cell viability (100%) of the photosensitive dye 1-1 was calculated by multiplying the result by 100%, and its killing effect on tumor cells was assessed accordingly. The results are as follows: Figure 5 As shown in the figure, the cell survival rate of photosensitive dye 1-1 was above 95% in the absence of light, while the cell survival rate at a concentration of 0.8 μM was only about 20% under light. This result indicates that photosensitive dye 1-1 can induce targeted photodynamic therapy of mitochondrial DNA under light conditions, exhibiting high cytotoxicity against tumor cells.

[0053] Example 2

[0054] The photosensitive dyes 1-2 were prepared using the following synthetic route:

[0055]

[0056] Synthesis of photosensitive dyes 1-2:

[0057] 5.0 mmol of compound A and 3.0 mmol of 1,2,3,3-tetramethyl-3H-indolon iodide were added to a round-bottom flask containing 30.0 mL of N,N-dimethylformamide. After stirring and mixing thoroughly, 1.5 mL of trimethylchlorosilane was added. The mixture was stirred and refluxed for 3.0 h before being stopped. The mixture was poured into ice water, and a precipitate formed. The precipitate was obtained by filtration and the crude product was a purple solid. The crude product was separated by column chromatography to obtain a purple solid powder compound, namely photosensitive dye 1-2, with a yield of 82%. 1 H NMR (600MHz, DMSO-d6) δ10.24(s,2H),9.66(s,1H),8.63(s,1H),7.99(s,1H),7.88(s,2H),7.66(s,1H),7.63(d,J=7.4Hz,1 H),7.47(d,J=7.9Hz,1H),7.43(t,J=7.5Hz,1H),7.28(d,J=6.4Hz,1H),4.16(s,1H),4.15(s,1H),3.70(s,3H),1.73(s,6H).

[0058] Assay for the responsiveness of photosensitive dyes 1-2 to mtDNA:

[0059] The synthesized photosensitive dyes 1-2 were added to PBS buffer (pH = 7.2) at a final concentration of 3.0 μM. Subsequently, mtDNA (0-10.16 μg / mL) was continuously added to the solution, and its UV absorption and fluorescence emission spectra were measured sequentially. The test results are as follows: Figure 6As shown, the results indicate that with increasing mtDNA content, its absorbance at 509 nm significantly decreases, and a slight red shift occurs. Simultaneously, its fluorescence signal at 567 nm significantly increases. This result demonstrates that photosensitive dyes 1-2 can also bind to mtDNA, and their content changes can be reflected through fluorescence signals.

[0060] Example 3

[0061] The photosensitive dyes 1-3 were prepared using the following synthetic route:

[0062]

[0063] Synthesis of photosensitive dyes 1-3:

[0064] 3.0 mmol of compound A and 10.0 mmol of 5-iodo-1,2,3,3-tetramethyl-3H-indolon iodide were added to a round-bottom flask containing 30.0 mL of N,N-dimethylformamide. After stirring and mixing thoroughly, 1.5 mL of trimethylchlorosilane was added. The mixture was stirred and heated to reflux for 3.0 h before being stopped. The mixture was poured into ice water, and a precipitate formed. The precipitate was obtained by filtration and a blue solid crude product was obtained. The blue solid powder compound, i.e., photosensitive dye 1-3, was obtained by column chromatography with a yield of 62%. 1 H NMR (600MHz, DMSO-d6) δ11.56(s,2H),8.97(s,1H),8.45(s,2H),8.08(d,J=40.9Hz,3H),7.83(d,J=75.3H z, 5H), 7.58 (d, J = 44.6Hz, 1H), 7.39 (d, J = 71.1Hz, 2H), 6.41 (d, J = 57.5Hz, 2H), 1.75 (s, 12H), 1.21 (s, 6H).

[0065] Assay for the responsiveness of photosensitive dyes 1-3 to mtDNA:

[0066] The synthesized photosensitive dyes 1-3 were added to PBS buffer (pH = 7.2) at a final concentration of 5.0 μM. DNA (0-10.16 μg / mL) was then continuously added to the solution, and the UV absorption and fluorescence emission spectra were measured sequentially. The test results are as follows: Figure 7 As shown, the results indicate that with increasing mtDNA content, both its absorbance at 618 nm and fluorescence signal at 637 nm significantly decreased. Simultaneously, a new fluorescence signal appeared at 676 nm, and its signal intensity increased significantly with increasing mtDNA content. This result demonstrates that photosensitive dyes 1-3 can bind to mtDNA, and their content changes can be reflected by significant changes in proportional fluorescence signals.

[0067] Example 4

[0068] The photosensitive dyes 1-4 were prepared using the following synthetic route:

[0069]

[0070] Synthesis of photosensitive dyes 1-4:

[0071] 3.0 mmol of compound A and 10.0 mmol of 1,2,3,3-tetramethyl-3H-indolon iodide were added to a round-bottom flask containing 30.0 mL of N,N-dimethylformamide. After stirring and mixing thoroughly, 1.5 mL of trimethylchlorosilane was added. The mixture was stirred and heated to reflux for 3.0 h before being stopped. The mixture was poured into ice water, and a precipitate formed. The precipitate was obtained by filtration and a blue solid crude product was obtained. The blue solid powder compound, i.e., photosensitive dye 1-4, was obtained by column chromatography with a yield of 52%. 1 H NMR(600MHz,DMSO-d6)δ8.55(d,J=8.2Hz,1H),8.42(s,1H),8.39(s,1H),8.11( t,J=7.8Hz,1H),7.96(d,J=9.1Hz,1H),7.82(t,J=7.7Hz,1H),7.73(d,J=7.3Hz ,3H),7.69–7.67(m,1H),7.54(d,J=8.0Hz,2H),7.48(t,J=7.6Hz,2H),7.37(t, J=7.4Hz,2H),7.16(s,1H),6.49(d,J=14.6Hz,2H),3.67(s,6H),1.79(s,12H).

[0072] Assay for the responsiveness of photosensitive dyes 1-4 to mtDNA:

[0073] The synthesized photosensitive dyes 1-4 were added to PBS buffer (pH = 7.2) at a final concentration of 5.0 μM. DNA (0-10.16 μg / mL) was then continuously added to the solution, and the UV absorption and fluorescence emission spectra were measured sequentially. The test results are as follows: Figure 8 As shown, the results indicate that the absorbance at 632 nm significantly decreases with increasing mtDNA content. Simultaneously, a new fluorescence signal appears at 700 nm, which increases sequentially with increasing mtDNA content. This result demonstrates that photosensitive dyes 1-4 can also bind to mtDNA, and changes in their content can be inferred from significant changes in fluorescence signal.

[0074] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A class of 4-aminobenzopyran photosensitizing dyes targeted to mitochondrial DNA, characterized by the following Compounds of structure .

2. A process for the preparation of the mitochondrial DNA-targeting 4-aminobenzopyran photosensitizing dye of claim 1, characterized by The specific preparation steps are as follows: Step S1: under acidic conditions, salicylamide, acetone and acetic anhydride are first added to a reaction solvent, then an oxidant is added and an oxidation reaction is carried out at 0-100℃ to obtain compound A, and the structural formula of the compound A is as follows: the oxidizing agent is one or more of potassium permanganate, hydrogen peroxide, sodium hypochlorite, Vilsmeier reagent, potassium dichromate, sodium dichromate, nitric acid, peroxyacetic acid, or chromic acid; Step S2: compound A obtained in step S1 is heated to reflux in reaction with 5-iodo-1,2,3,3-tetramethyl-3H-indolium iodide or 1,2,3,3-tetramethyl-3H-indolium iodide to obtain compounds shown in formula 1-1~formula 1-4, i.e. mitochondrial DNA-targeted 4-aminobenzopyran photosensitizer dyes.

3. The method for preparing mitochondrial DNA-targeting 4-aminobenzopyran-based photosensitive dyes according to claim 2, characterized in that: The molar ratio of salicylamide, acetone and acetic anhydride in step S1 is 1:1:1-1:2:

2.

4. The method for preparing mitochondrial DNA-targeting 4-aminobenzopyran-based photosensitive dyes according to claim 2, characterized in that: The reaction solvent in step S1 is one or more of dichloromethane, ethanol, methanol, acetone, 1,4-dioxane, glycerol, ethyl acetate, acetic acid, sulfuric acid, acetic anhydride, aqueous sodium hydroxide or N,N-dimethylformamide.

5. The method for preparing mitochondrial DNA-targeting 4-aminobenzopyran-based photosensitive dyes according to claim 2, characterized in that: The molar ratio of compound A to 5-iodo-1,2,3,3-tetramethyl-3H-indolium iodide or 1,2,3,3-tetramethyl-3H-indolium iodide in step S2 is 1:0.5-1:

4.

6. The method for preparing mitochondrial DNA-targeting 4-aminobenzopyran-based photosensitive dyes according to claim 2, characterized in that: The reaction solvent in step S2 is one or more of dichloromethane, ethanol, methanol, acetone, 1,4-dioxane, glycerol, ethyl acetate, acetic acid, sulfuric acid, piperidine or N,N-dimethylformamide.

7. Use of the mitochondrial DNA-targeted 4-aminobenzopyran photosensitizer dye of claim 1 in the preparation of a mitochondrial DNA photosensitive imaging agent.

8. Use of the mitochondrial DNA-targeted 4-aminobenzopyran photosensitizer dye of claim 1 in the preparation of a mitochondrial DNA-targeted tumor photodynamic therapy photosensitizer, wherein the tumor is breast cancer.

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