An organic photothermal conversion reagent and its preparation method and application
By constructing FCDTDPP through the fused ring CDT-based DPP molecule, the problem of insufficient conjugation of organic small molecule dye-based photothermal conversion reagents was solved, achieving efficient photothermal conversion and thermal treatment effects on cancer cells.
Patent Information
- Application Number
- CN202411099556.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-12
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2044-08-12
AI Technical Summary
The degree of conjugation of existing organic small molecule dye-based photothermal conversion reagents is poor, resulting in insufficient photothermal conversion efficiency, which is difficult to meet the needs of photothermal therapy.
By condensing the cyclopentadithiophene (CDT)-based DPP molecule to construct the molecule FCDTDPP, its application in photothermal imaging and therapy, including 660nm photothermal imaging and 660nm photothermal therapy, is realized.
It achieved efficient photothermal conversion, was able to realize thermal imaging and in vitro cancer cell killing treatment under 660nm light, and showed significant thermal imaging effects in mice.
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Figure CN118994193B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of organic material chemistry and relates to an organic photothermal conversion reagent and a preparation method and application thereof. Background Art
[0002] The photothermal effect refers to the electrical properties of a material that change due to changes in temperature. In the past decade, many inorganic photothermal conversion materials, especially gold and carbon nanomaterials, have been widely used in application research such as photothermal therapy. In recent years, organic photothermal conversion reagents have developed rapidly because they can overcome the non-biodegradable characteristics of inorganic materials. Organic photothermal conversion reagents include small molecule dyes, supramolecular complexes and conjugated polymers, which are used in the research of photothermal therapy for tumors. However, there are currently few reports on organic small molecule dye photothermal conversion reagents, mainly because their degree of conjugation is poor, making it difficult to improve the photothermal conversion efficiency.
[0003] Diketopyrrolopyrrole (DPP) and its derivatives have been extensively studied in the past few years due to their inherent physical and chemical properties, such as strong electron-withdrawing properties, dark color, high charge carrier mobility, strong aggregation, and good thermal and photostability. DPP-based polymers have been widely used in photothermal conversion materials. However, reports on small-molecule photothermal conversion materials based on DPP are limited. Studies have shown that by condensing the DPP backbone and expanding its absorption spectrum, visible light photothermal conversion is possible. Currently, photothermal conversion based on condensed-ring DPP systems has not been reported. Summary of the Invention
[0004] The present invention aims to provide an organic photothermal conversion reagent, its preparation method, and its application. By cyclizing a cyclopentadithiophene (CDT)-based DPP molecule to construct the molecule FCDTDPP, the reagent has been applied in photothermal imaging and therapy, including 660nm-based thermal imaging, 660nm-based thermogenic therapy for killing cancer cells in vitro, and 660nm-based in vivo thermal imaging in mice.
[0005] The present invention provides a compound, the structural formula of which is shown in Formula I:
[0006]
[0007] In formula I, R is selected from a C1-C20 straight or branched chain alkyl group.
[0008] In the present invention, the compound represented by formula I is an organic photothermal conversion reagent based on a fused-ring DPP system (abbreviated as FCDTDPP in English).
[0009] In the above compounds, R is selected from a C1-C10 straight-chain or branched alkyl group, and specifically a C9 branched alkyl group (2-ethylhexyl).
[0010] The present invention also provides a method for preparing the above-mentioned compound, comprising the following steps: 1) mixing the compound represented by Formula II and 2-bromo-1,1-diethoxyethane in an organic solvent in an inert atmosphere in the presence of a base to react to obtain a compound represented by Formula III;
[0011]
[0012] In formula II and III, R is the same as that in formula I;
[0013] 2) Under an inert atmosphere and in the presence of a Lewis acid, the compound represented by formula III is subjected to a ring-closure reaction in an organic solvent to obtain the compound represented by formula I.
[0014] In the above preparation method, in step 1), the inert atmosphere gas is nitrogen;
[0015] The base is an inorganic base salt, and the inorganic base salt is selected from at least one of potassium carbonate, sodium carbonate, sodium bicarbonate, and potassium phosphate;
[0016] The molar ratio of the compound represented by formula II, the base and 2-bromo-1,1-diethoxyethane may be 1:5-35:2-15; specifically, 1:15:10, 1:5-15:2-10, 1:15-35:10-15 or 1:10-20:5-15;
[0017] The reaction temperature may be 90-150° C., specifically 130° C., 90-130° C., 130-150° C., or 120-140° C., and the reaction time may be 10-72 h, specifically 17 h, 10-17 h, 17-72 h, or 10-50 h.
[0018] The organic solvent is selected from at least one of nitrogen-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAC) and tetrahydrofuran (THF).
[0019] In the above preparation method, in step 2), the inert atmosphere gas is nitrogen;
[0020] The Lewis acid is at least one of aluminum trichloride, boron trifluoride, sulfur trioxide and ferric bromide, and specifically aluminum trichloride;
[0021] The molar ratio of the compound represented by formula III to the Lewis acid may be 1:2.5-50, specifically 13:150, 1:2.5-11.6, 11.5-50 or 1:7.5-20;
[0022] The reaction temperature of the reaction is room temperature, and the reaction time can be 4 to 24 hours, specifically 12 hours, 4 to 12 hours, 12 to 24 hours or 10 to 20 hours;
[0023] The organic solvent is at least one of dichloromethane, chloroform and tetrahydrofuran (THF).
[0024] In the above preparation method, the ring-closure reaction process is to first mix the compound of formula III, the Lewis acid and the solvent, and react to obtain the compound of formula I.
[0025] The present invention also provides an organic photothermal conversion reagent, the active ingredient of which is the compound represented by the above formula I.
[0026] The present invention further provides the use of the compound represented by formula I or the organic photothermal conversion agent in photothermal imaging.
[0027] In the above application, the excitation wavelength of the photothermal imaging is 660 nm.
[0028] In the present invention, the compound represented by Formula I or the organic photothermal conversion reagent is used in the photothermal imaging and cancer treatment; specifically, it includes 660nm light-irradiated thermal imaging, 660nm light-irradiated heat-generated in vitro cancer cell killing treatment (specifically breast cancer cells), and 660nm light-irradiated in vivo thermal imaging in mice.
[0029] The compound represented by formula I or the organic photothermal conversion reagent according to claim 6, polyethylene glycol lipid and solvent.
[0030] The present invention further provides a nanoparticle for photothermal imaging, comprising the compound represented by formula I or the organic photothermal conversion agent, polyethylene glycol lipid and a solvent.
[0031] In the aforementioned nanoparticles for photothermal imaging, the solvent is specifically selected from tetrahydrofuran and / or dioxane.
[0032] In the nanoparticles for photothermography, the concentration of the FCDTDPP mixed with the solvent may specifically be 1 mg / mL to 10 mg / mL.
[0033] The method for preparing nanoparticles for photothermal imaging of the present invention comprises the following steps: mixing the compound represented by Formula I or the organic photothermal conversion reagent, the polyethylene glycol lipid (DSPE-PEG200), and the solvent 1, adding the mixture to secondary water to obtain a nanoparticle micelle solution, then adding the mixture to an imaging mold, and irradiating the solution with a 660 nm laser to achieve thermal imaging in cells in vitro or in mice;
[0034] The present invention has the following beneficial effects:
[0035] The FCDTDPP represented by Formula I provided by the present invention has photothermal conversion properties and can achieve thermal imaging (specifically, thermal imaging in mice) and in vitro cancer cell killing therapy. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Figure 1 The chemical reaction flow chart of compound 1 shown in formula III.
[0037] Figure 2 This is the hydrogen spectrum of compound 1 represented by formula III in Example 1.
[0038] Figure 3 The chemical reaction flow chart of compound 2 shown in formula I is shown in FIG.
[0039] Figure 4 This is the hydrogen spectrum of compound 2 represented by formula I in Example 2.
[0040] Figure 5 This is a time-temperature curve of compound 2 represented by formula I in Example 3.
[0041] Figure 6 This is a photothermal image of compound 2 represented by formula I in Example 4.
[0042] Figure 7 This is a diagram showing the photothermal treatment of compound 2 represented by formula I in Example 5 for killing cancer cells in vitro.
[0043] Figure 8 This is a thermal imaging image of cancer cells in mice containing compound 2 represented by formula I in Example 6. DETAILED DESCRIPTION
[0044] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.
[0045] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.
[0046] Example 1, Synthesis of Compound 1 shown in Formula III (in which R is 2-ethylhexyl):
[0047] Chemical reaction flow chart Figure 1 As shown, the specific reaction step conditions of compound 1 shown in formula III are as follows:
[0048] To a 50 mL glass tube, the compound represented by Formula II (R = 2-ethylhexyl, 1.16 mmol, 1.09 g), 2-bromo-1,1-diethoxyethane (11.6 mmol, 1.75 g), potassium carbonate (17.4 mmol, 2.4 g), and N-methylpyrrolidone (NMP, 100 mL) were added. The reaction mixture was heated to 130°C for 17 h. After returning to room temperature (25°C), compound 1 (810 mg) was isolated by column chromatography in a 60% yield.
[0049] The structural confirmation data are as follows:
[0050] Proton spectrum Figure 2 As shown, specifically (600 MHz, Chloroform- d ) δ 8.83 – 8.74 (m, 2H),7.30 (d, J = 4.8 Hz, 2H), 6.99 (dd, J = 5.1, 2.9 Hz, 2H), 4.92 (tt, J = 5.8, 2.4Hz, 2H), 4.23 (t, J = 2.8 Hz, 4H), 3.83 – 3.79 (m, 4H), 3.56 (ddd, J = 8.1, 5.4,2.6 Hz, 4H), 2.05 – 1.91 (m, 8H), 1.19 – 1.15 (m, 12H), 1.00 – 0.88 (m, 32H), 0.77 – 0.74 (m, 6H), 0.72 – 0.68 (m, 6H), 0.60 (td, J = 7.4, 2.7 Hz, 16H).
[0051] High-resolution mass spectrometry HR-MS (MALDI-TOF): calcd. for C 68 H 100 N2O6S4[MH] + 1169.6542;Found: 1169.6540.
[0052] From the above, we can see that the product structure is correct.
[0053] Example 2, compound 2 shown in formula I (in compound 2, R is 2-ethylhexyl):
[0054] Chemical reaction flow chart Figure 3As shown, the specific reaction conditions of compound 2 shown in formula I are as follows:
[0055] To a 50 mL round-bottom flask was added compound 1 (R = 2-ethylhexyl, 0.013 mmol, 15 mg) of Formula III, aluminum chloride (0.15 mmol, 20 mg), and chloroform (1 mL). The reaction mixture was stirred at room temperature (25°C) for 12 hours. Compound 2 (3.5 mg) was isolated by column chromatography in a 27% yield.
[0056] The structural confirmation data are as follows:
[0057] Proton spectrum Figure 4 As shown, specifically (400 MHz, Chloroform- d ) δ 8.03 (d, J = 6.7 Hz, 2H),7.40 (d, J = 4.8 Hz, 2H), 7.05 (dd, J = 4.9, 2.5 Hz, 2H), 6.88 (dd, J = 7.2, 4.6Hz, 2H), 2.19 – 2.02 (m, 8H), 1.05 – 0.67 (m, 40H), 0.63 – 0.57 (m, 8H), 0.58 – 0.48 (m, 12H).
[0058] High-resolution mass spectrometry (MALDI-TOF): calcd. for C 60 H 76 N2O2S4[MH] + 985.4868; Found:985.4860.
[0059] From the above, we can see that the product structure is correct.
[0060] Example 3: Temperature-time changes of Formula I according to the present invention with light irradiation.
[0061] 2 mg of compound 2 (compound of formula I) prepared in Example 2 of the present invention and 10 mg of DSPE-PEG2000 were dissolved in tetrahydrofuran to a concentration of 2 mg / mL of compound 2 in tetrahydrofuran, and then poured into 10 mL of secondary water. After ultrasonication (150 W) for 5 minutes, the mixture was filtered through a PVDF filter membrane and placed in a 4 o C. Afterwards, dilute it with PBS solution before use;
[0062] The compound of Example 3 of the present invention was diluted to 100 μM (PBS solution) and irradiated with a 660 nm laser at a power of 0.5 W / cm 2 The system temperature was measured using a photothermal imager (FLIR E8-XT camera), and the time-temperature diagram is shown in Figure 2. Figure 5 As shown, from Figure 5 It can be seen that the temperature of the system gradually increases with time and can reach 80 o C, the calculated photothermal conversion efficiency (ƞ) is 58.3%, indicating that compound 2 described in formula I of the present invention has photothermal conversion properties.
[0063] Example 4: Photothermal imaging of the compound represented by formula I of the present invention
[0064] Compound 2 (compound represented by formula I) prepared in Example 2 of the present invention was placed in the molds of letters "L" and "Z" and irradiated with a 660 nm laser for 90 s (power of 0.3 W / cm 2 ), and monitor the system temperature and thermal imaging through a photothermal imager (FLIR E8-XT camera), and its imaging and temperature are Figure 6 As shown. Figure 6 It can be seen that under 660nm laser irradiation, thermal imaging "L" and "Z" images were successfully obtained, and the temperature increased with the increase of irradiation time. When 90s, the system temperature can reach 60 o C, indicating that the compound 2 described in formula I has photothermal imaging characteristics.
[0065] Example 5: In vitro cancer cell killing therapy using the compound of formula I of the present invention to generate heat through photoirradiation
[0066] 4T1 breast cancer cells (mouse breast cancer cells, purchased from Los Angeles Parker Memorial Institute) were seeded in RPMI1640 medium (containing 10% fetal bovine serum and 1% penicillin / streptomycin) and cultured at 37 o C humidified culture. Then, the cells in the growth phase were harvested and seeded in 96-well plates at a density of 5000 cells and incubated for 24 h. Subsequently, the culture medium was replaced with fresh culture medium containing 25 μM nanoparticle micelle solution of compound 2 represented by formula I of the present invention. After further incubation for 20 h, the cells were exposed to 660 nm (0.4 W / cm 2 ) laser irradiation for 10 minutes. After a further 4 hours of incubation, the culture medium was removed and incubated in fresh serum-free medium containing 10% CCK-8 in the dark for 1 hour. Finally, the absorbance of the product at a wavelength of 450nm and imaging were measured using a microplate reader and a fluorescence instrument to determine cell survival rate. The photothermogenic in vitro cancer cell killing therapeutic effect is shown in the figure below. Figure 7 As shown. Figure 7It can be seen that ((PBS+Dark) means cells only, (PBS+Light) means cells only after illumination; (2+Dark) means cells with the addition of compound 2 shown in formula I; (2+Light) means cells with the addition of compound 2 shown in formula I and illumination; Brightfield means imaging under visible light; Caicein-AM means imaging with the addition of a green fluorescent probe, which can be used for imaging living cells; PI is a nuclear stain (Propidium Iodide), which can be used for imaging dead cells; Merge means mixing Caicein-AM and PI). Without the addition of compound 2 shown in formula I, 4T1 breast cancer cells survived both under illumination and without illumination. After the addition of compound 2 shown in formula I, 4T1 breast cancer cells survived without illumination, but after illumination (660 nm (0.4 W / cm 2 ) laser irradiation for 10 minutes), 4T1 breast cancer cells were killed (green fluorescence weakened, red fluorescence enhanced). Microplate reader measurement showed that 80% of the 4T1 breast cancer cells were killed, indicating that compound 2 represented by formula I of the present invention can kill cancer cells when the temperature increases under laser irradiation, and has a therapeutic effect.
[0067] Example 6: Photothermal imaging of the compound represented by formula I of the present invention in mice
[0068] BALB / c mice (6–8 weeks old, average weight 16–18 g) were purchased from SPF Biotechnology Co., Ltd. (Beijing, China). All animal experiments were performed in accordance with protocols approved by the Institutional Animal Care and Use Committee (Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences). All animals were housed under pathogen-free conditions at 25°C and 55% humidity and had free access to standard laboratory water and food. To establish the xenograft 4T1 tumor-bearing mouse model, 4T1 breast cancer cells (1 × 10 cells / mL) suspended in 100 µL of PBS buffer were inoculated with 4T1 breast cancer cells (1 × 10 cells / mL). 6 ) was injected subcutaneously into the right flank of each mouse. About 7 days later, the tumor volume was about 100 mm 3 The tumor volume was measured every other day using a caliper and the calculation formula was as follows: volume = (tumor length) × (tumor width) 2 ) / 2. 4T1 tumor-bearing mice were randomly divided into two groups (n = 5 in each group), named "physiological saline + laser" (PBS+L) and "compound 2 shown in formula I + laser" (2+L). Mice in the "physiological saline + laser" group and the "compound 2 shown in formula I + laser" group were injected with physiological saline or compound 2 shown in formula I (200 μL, 500 μM, whichever is greater) for 24 h, and then treated with 660 nm (0.6 W cm -2) laser irradiation for 10 min. 24 h after administration of 2, the images were taken with a FLIR E8-XT camera using a 660 nm laser (0.6 W·cm -2 ) irradiated for 10 min. The photothermal imaging of the compound represented by Formula I in mice is shown in FIG. Figure 8 As shown. Photothermal image and temperature distribution of mice ( Figure 8 ) clearly demonstrated that after injection of compound 2 of Formula I, the tumor temperature of mice increased from 30.6°C to 50.4°C within 4 minutes. Notably, even after 10 minutes of continuous 660 nm laser irradiation, the temperature remained stable at approximately 50°C, sufficient to ablate tumor tissue. In contrast, tumors in mice treated with PBS exhibited only a slight temperature increase (~5°C) over the same period. These experimental results demonstrate the potential of compound 2 of Formula I of the present invention for biomedical applications in photothermal therapy.
Claims
1. Use of the compound represented by formula I in the preparation of an organic photothermal conversion reagent, characterized in that: The structural formula of the compound shown in Formula I is as follows: In formula I, R is selected from a C1-C20 straight or branched chain alkyl group.
2. The use according to claim 1, characterized in that R is selected from C1-C10 linear or branched alkyl groups.
3. The use according to claim 1 or 2, characterized in that: The method for preparing the compound represented by formula I comprises the following steps: 1) mixing the compound represented by formula II and 2-bromo-1,1-diethoxyethane in an organic solvent in an inert atmosphere and in the presence of a base to react to obtain the compound represented by formula III; In formula II and III, R is the same as that in formula I; 2) Under an inert atmosphere and in the presence of a Lewis acid, the compound represented by formula III is subjected to a ring-closure reaction in an organic solvent to obtain the compound represented by formula I.
4. The use according to claim 3, characterized in that In step 1), the inert atmosphere is nitrogen; The base is an inorganic base salt, and the inorganic base salt is selected from at least one of potassium carbonate, sodium carbonate, sodium bicarbonate, and potassium phosphate; The molar ratio of the compound represented by formula II, the base and 2-bromo-1,1-diethoxyethane may be 1:5-35:2-15; The reaction temperature can be 90-150° C., and the reaction time can be 10-72 hours; The organic solvent is selected from at least one of nitrogen-methyl pyrrolidone, nitrogen-nitrogen dimethylformamide, nitrogen-nitrogen dimethylacetamide and tetrahydrofuran.
5. The use according to claim 3, characterized in that In step 2), the inert atmosphere is nitrogen; The Lewis acid is at least one of aluminum trichloride, boron trifluoride, sulfur trioxide and ferric bromide; The molar ratio of the compound represented by formula III to the Lewis acid may be 1:2.5-50; The reaction temperature is room temperature and the reaction time is 4 to 24 hours; The organic solvent is at least one of dichloromethane, chloroform and tetrahydrofuran.
6. Use of the compound represented by formula I in photothermal imaging; The structural formula of the compound shown in Formula I is as follows: In formula I, R is selected from a C1-C20 straight or branched chain alkyl group.
7. The use according to claim 6, characterized in that R is selected from C1-C10 linear or branched alkyl groups.
8. The use according to claim 6, characterized in that The excitation wavelength of the photothermal imaging is 660 nm.
9. A nanoparticle for photothermal imaging, characterized in that: It comprises a compound represented by formula I, a polyethylene glycol lipid and a solvent; The structural formula of the compound shown in Formula I is as follows: In formula I, R is selected from a C1-C20 straight or branched chain alkyl group.
10. The nanoparticles for photothermal imaging according to claim 9, characterized in that: R is selected from C1-C10 linear or branched alkyl groups.
11. The nanoparticles for photothermal imaging according to claim 9, characterized in that: The solvent is selected from tetrahydrofuran and / or dioxane; The concentration of the compound represented by Formula I or the organic photothermal conversion reagent mixed with the solvent is 1 mg / mL to 10 mg / mL.
12. A method for preparing nanoparticles according to claim 9, characterized in that: The steps include: The compound represented by formula I is mixed with the polyethylene glycol lipid and the solvent to obtain a micellar solution containing the nanoparticles for photothermal imaging.