Carbazole derivative modified D-A-D molecule and application thereof

Abstract

The invention provides a carbazole derivative-modified D-A-D molecule and application, the carbazole derivative-modified D-A-D molecule has a general formula shown as a formula (I): # imgabs0 #, the D-A-D molecule has the characteristic of high brightness, and compared with an existing S-D-A-D-S molecule with an alkyl substituted fluorene structure, the D-A-D molecule has a better imaging effect in a near-infrared two-region window, and can be applied to the field of near-infrared imaging. The method can be used for developing various focuses in vivo, especially developing tiny focuses.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis and imaging, and in particular to DAD molecules modified with carbazole derivatives and applications thereof. Background Art

[0002] Donor-acceptor-donor small molecules (DAD molecules) are well-known organic NIR-II emitters with high fluorescence quantum yield and strong photostability. In 2016, Dai et al. constructed the first DAD structure small molecule dye CH1055 with NIR-II imaging characteristics using triphenylamine as donor and BBTD as acceptor. Subsequently, researchers improved the DAD structure with different strategies to obtain near-infrared second-zone fluorescent probes with better performance. In order to obtain longer emission wavelengths, there are many reports on the design of donors and acceptors. Hong et al. used 2-amino 9,9-dialkyl substituted fluorene as a donor to design the NIR-II bioimaging molecule H1. [1] The modified fluorene unit distorts the BBTD main chain, thereby reducing intermolecular interactions, increasing intermolecular distances, and improving fluorescence QY to a certain extent. PEGylated H1 has good biocompatibility and clearance efficiency, and can reach a renal clearance rate of 90% within a few hours after injection. Jiang et al. designed and synthesized DAD structure fluorophores TPB-AM, TPB-BAM, and TPBAZO using amino, tert-butyl carbonyl, and benzoazole functionalized triphenylamine as electron donor moieties, respectively. [2] TPB-AZO showed a blue-shifted emission peak at 909nm, but the QY value was high at 21.59%. The red-shifted emission and weak QY of TPB-AM and TPB-BAM were attributed to the amino group in the donor part, which enhanced the ICT effect. Ma et al. designed the molecule FM1210 with BSBT as the acceptor and compared it with the molecule CF1065 with BBTD as the acceptor. FM1210 showed a significant red shift of 145nm, and the introduction of Se had little effect on QY and brightness. [3] The maximum absorption and emission wavelengths of CF1065 in dichloromethane solution are 855 nm and 1065 nm, respectively, while the maximum absorption and emission wavelengths of FM1210 are 980 nm and 1210 nm, respectively.

[0003] In addition, introducing shielding units at the ends of molecules to improve quantum yield has also become a common method in the field, such as alkyl-substituted fluorene. In 2017, Dai et al. designed the first SDADS-structured NIR-II fluorophore IR-FE, in which BBTD is the acceptor, 3,4-ethylenedioxythiophene (EDOT) is the donor, and dialkyl fluorene is the shielding unit. IR-FE showed a QY of up to 31% in toluene solution. [4]In addition, PEGylated IR-FEP exhibited enhanced fluorescence properties in water with a QY of 2.0%. Dai et al. further synthesized the fluorophore IR-FTA with a S-D2-D1-A-D1-D2-S structure using octylthiophene as the first donor and thiophene as the second donor based on IR-FE. Multiple donors increased the length of the conjugate, while octylthiophene increased the dihedral angles of the donor and acceptor and the overall hydrophobicity to improve the QY. Under 808nm laser excitation, the PEGylated IR-FTAP had an emission peak at 1048nm, and the QY in water was increased to 5.3%. [5]

[0004] However, most of these DAD molecules obtained by the aforementioned technology need to be further encapsulated and modified with amphiphilic polymers to obtain the required water solubility, thereby meeting the requirements of in vivo applications, but this also brings a series of problems, such as the quenching effect caused by aggregation and the blue shift of absorption and emission, which may affect the NIR-II luminescence performance of fluorescent dyes. Therefore, in order to obtain better actual imaging effects, it is necessary to further optimize the DAD molecular structure to improve the photophysical parameters after being encapsulated into nanoparticles.

[0005] References are as follows:

[0006] [1] Y. Sun, M. Ding, X. Zeng, Y. Xiao, H. Wu, H. Zhou, B. Ding, C. Qu, W. Hou, A. Er-Bu, Y. Zhang, Z. Cheng, X. Hong, Chem. Sci. 2017, 8, 3489–3493.

[0007] [2]L.Zhang,C.Liu,S.Zhou,R.Wang,Q.Fan,D.Liu,W.Wu,X.Jiang,Adv.Healthc.Mater.2020,9,1901470.

[0008] [3]Y.Fang,J.Shang,D.Liu,W.Shi,X.Li,H.Ma,J.Am.Chem.Soc.2020,142,15271–15275. [4] Q. Yang, Z. Ma, H. Wang, B. Zhou, S. Zhu, Y. Zhong, J. Wang, H. Wan, A. Antaris, R. Ma, X. Zhang, J. Yang, X. Zhang, H. Sun, W. Liu, Y. Liang, H. Dai, Adv. Mater. 2017, 29, 1605497.

[0009] [5] Q. Yang, Z. Hu, S. Zhu, R. Ma, H. Ma, Z. Ma, H. Wan, T. Zhu, Z. Jiang, W. Liu, L. Jiao, H. Sun, Y. Liang, H. Dai, J. Am. Chem. Soc. 2018, 140, 1715–1724. Summary of the invention

[0010] In view of this, in view of the problems pointed out in the background technology, the present invention provides a DAD molecule modified with a carbazole derivative and its application. The DAD molecule has the characteristics of high brightness and has a good imaging effect in the near-infrared second zone window.

[0011] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0012] In a first aspect, the present invention provides a DAD molecule modified with a carbazole derivative, wherein the DAD molecule modified with a carbazole derivative has a general formula as shown in formula (I):

[0013] in:

[0014] The dotted line between R2 and R3 indicates that there is no chemical bond between R2 and R3, or that the chemical bond between R2 and R3 is a single bond or a double bond;

[0015] R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy;

[0016] When there is no chemical bond between R2 and R3, R2 and R3 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy; R4 does not represent any group;

[0017] When there is a chemical bond between R2 and R3, R2, R3 and the C atom connected thereto together form a 5-7 membered heterocyclic group, aromatic ring group or heteroaryl group; R2, R3 are independently selected from: H, CH, N, NH, CR5, NR6, CHR7, C(R8)2; R4 is selected from: H, C1-C6 alkyl, C1-C6 alkoxy; R5, R6, R7, R8 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy.

[0018] Preferably, the DAD molecule modified with the carbazole derivative has the general formula shown in formula (II):

[0019] in:

[0020] R1 and R2 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy.

[0021] Preferably, the DAD molecule modified with the carbazole derivative has the general formula (III): in:

[0022] R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy;

[0023] R4 is selected from: H, C1-C6 alkyl, C1-C6 alkoxy.

[0024] Preferably, R4 is selected from: H.

[0025] Preferably, the DAD molecule modified with the carbazole derivative is selected from the following compounds:

[0026]

[0027]

[0028] In a second aspect, the present invention provides the use of the DAD molecule modified with the carbazole derivative described in the first aspect in preparing functional nanoparticles.

[0029] In a third aspect, the present invention provides a method for preparing functional nanoparticles, comprising the following steps:

[0030] Step 1, dispersing the DAD molecules modified with the carbazole derivatives described in the first aspect in a solvent, adding DSPE-PEG2000 to mix, and adding the mixture into ultrapure water for ultrasonic dispersion;

[0031] Step 2, removing the solvent in the system after ultrasonic dispersion and separating the solid therein to obtain the functional nanoparticles.

[0032] Preferably, in the step 1, the mass ratio of the DAD molecule modified with the carbazole derivative to DSPE-PEG2000 is 1:1-10; and / or, the solvent is a polar organic solvent, more preferably an alkyl ether, a lower carboxylic acid ester, an alkyl alcohol, or an aromatic hydrocarbon containing a benzene ring; and / or, in the step 2, a 0.22 μm PES filter is used to separate the solid.

[0033] In a fourth aspect, the present invention provides functional nanoparticles obtained by the preparation method described in the third aspect.

[0034] In a fifth aspect, the present invention provides the use of the functional nanoparticles described in the fourth aspect in preparing luminescent materials.

[0035] In the present invention, the luminescent material is mainly used for vascular imaging, tumor development, tumor micrometastasis development, fluorescence navigation surgery, etc.

[0036] The beneficial effects of the present invention are:

[0037] The present invention designs and synthesizes a DAD molecule modified with a carbazole derivative. The DAD molecule has the characteristic of high brightness. Compared with the SDADS molecule with an alkyl-substituted fluorene structure (TBTF, reported in literature [5]) reported previously, the DAD molecule has better imaging effect in the near-infrared second window and can be used for the development of various lesions in the body, especially the development of micro-lesions. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the H NMR result of compound 5 in Example 1 of the present invention.

[0039] Figure 2 This is the carbon NMR result of compound 5 in Example 1 of the present invention.

[0040] Figure 3 This is the H NMR result of compound 2 in Example 1 of the present invention.

[0041] Figure 4 This is the carbon NMR result of compound 2 in Example 1 of the present invention.

[0042] Figure 5 This is the H NMR result of compound I in Example 1 of the present invention.

[0043] Figure 6 This is the carbon NMR result of compound I in Example 1 of the present invention.

[0044] Figure 7 This is the H NMR result of compound 6 in Example 2 of the present invention.

[0045] Figure 8 This is the carbon NMR result of compound 6 in Example 2 of the present invention.

[0046] Fig. 9 This is the H NMR result of compound 3 in Example 2 of the present invention.

[0047] Fig.10 This is the carbon NMR result of compound 3 in Example 2 of the present invention.

[0048] Fig.11 This is the hydrogen nuclear magnetic resonance result of compound II in Example 2 of the present invention.

[0049] Fig.12 This is the carbon NMR result of compound II in Example 2 of the present invention.

[0050] Fig.13 This is the H NMR result of compound 7 in Example 3 of the present invention.

[0051] Fig.14 This is the carbon NMR result of compound 7 in Example 3 of the present invention.

[0052] Fig.15 This is the H NMR result of compound 4 in Example 3 of the present invention.

[0053] Fig.16 This is the carbon NMR result of compound 4 in Example 3 of the present invention.

[0054] Fig.17 This is the H NMR result of compound III in Example 3 of the present invention.

[0055] Fig.18 This is the carbon NMR result of compound III in Example 3 of the present invention.

[0056] Fig.19 This is the hydrogen nuclear magnetic resonance result of the compound TBTF in Example 4 of the present invention.

[0057] Fig. 20 This is the carbon NMR result of the compound TBTF in Example 4 of the present invention.

[0058] Fig.21 The particle size of the nanoparticles measured by dynamic light scattering instrument and its TEM image in Example 5 of the present invention, wherein the scale bars for A. TBTF, B. TBTC-1, C. TBTC-2 and D. TBTC-3 are 100 nm.

[0059] Fig. 22 The changes in 4T1 cell viability after incubation for 48 hours with nanoparticles of different concentrations in Example 6 of the present invention, wherein A. TBTF; B. TBTC-1; C. TBTC-2; D. TBTC-3 nanoparticles.

[0060] Fig.23 The changes in the viability of MCF-7 cells after incubation with nanoparticles of different concentrations for 48 hours in Example 6 of the present invention, wherein A. TBTF; B. TBTC-1; C. TBTC-2; D. TBTC-3 nanoparticles.

[0061] Fig.24 These are the UV absorption spectra and fluorescence emission spectra of different small molecules and nanoparticles in Example 9 of the present invention, wherein: A. UV-visible absorption spectra of different small molecules (filled with white) and nanoparticles (filled with different transparent colors); B. fluorescence emission spectra of different small molecules (filled with white) and nanoparticles (filled with different transparent colors).

[0062] Fig.25 This is the imaging of the blood vessels in the hind limbs of nude mice by intravenous injection of different nanoparticles under different wavelength filter conditions in Example 10 of the present invention. Different wavelength filters: 1000lp, 1100lp, 1300lp (scale bar is 1cm), nanoparticle injection volume (200μg / mL, 50μL).

[0063] Fig.26 for Fig.25 NIR-II fluorescence intensity diagram of the linear region of interest. The left side of the figure lists the SBRs under different wavelength filter conditions. A. TBTF; B. TBTC-1; C. TBTC-2; D. TBTC-3.

[0064] Fig. 27 FA functionalized TBTC-3 nanoparticles targeted tumor imaging in Example 11 of the present invention. A. NIR-II images of 4T1 tumor-bearing BALB / c mice at different time points after intravenous injection of FA functionalized TBTC-3 nanoparticles (200 μg / mL, 50 μL) with a 1100lp filter; B. NIR-II images of the same mouse 24 hours after intravenous injection of FA functionalized TBTC-3 nanoparticles (200 μg / mL, 50 μL) with 1100lp and 1000lp filters; C. Fluorescence intensity graph corresponding to the linear region of interest.

[0065] Fig.28 This is a bright field image (Figure A) and a NIR-II fluorescence image (Figure B) of the anatomical organs of 4T1 tumor-bearing BALB / c mice in Example 11 of the present invention.

[0066] Fig.29 The images are of 4T1 tumor-bearing BALB / c mice at different time points after intravenous injection of TBTC-3 nanoparticles in Example 11 of the present invention. Injection volume of TBTC-3 nanoparticles (200 μg / mL, 50 μL).

[0067] Fig.30 The results of imaging of distal metastases of tumors by FA-functionalized TBTC-3 nanoparticles in Example 11 of the present invention. A. Images of BALB / c mice with 4T1 tumor metastasis at different time points after intravenous injection of FA-functionalized TBTC-3 nanoparticles (200 μg / mL, 50 μL); B. Images of mice before and after NIR-II signal excision of 1-6 small tissues; C. Bright field view (top) and NIR-II image (bottom) of excised tissue and H&E staining image of paraffin-embedded tissue sections (scale bar is 500 μm), as well as magnified images of cancer cell areas (scale bar is 50 μm). DETAILED DESCRIPTION

[0068] In the description of the present invention, it should be noted that, if the specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0069] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are not a limitation of the technical solutions of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] In the embodiments of the present invention, the present invention provides the preparation method of the DAD molecule shown in compounds 1 to 10 as an example, rather than limiting the protection scope of the present invention to these 10 compounds, the compounds belonging to the scope of general formula (I) can be obtained by referring to the following preparation process. The specific reaction formula of compounds 1 to 10 is as follows:

[0071] (1) Compounds 1 to 6 are prepared by reaction equation 1:

[0072] Reaction equation 1:

[0073]

[0074] Wherein, R1 is selected from: H, methyl, ethyl, methoxy, ethoxy; R2 is selected from: H, methyl.

[0075] (1) Compounds 7 to 10 are prepared by reaction equation 2:

[0076] Reaction equation 2:

[0077]

[0078] Wherein, R1 is selected from: H, methyl; R4 is selected from: H, methyl, methoxy.

[0079] In the reaction equations 1 to 2, preferably, the reaction temperature is 110±2°C; and / or, the reaction endpoint is determined by TLC; and / or, the main catalyst is Pd(Ph 3 ) 4 , auxiliary catalyst is K 2 CO 3 ; and / or, the reaction solvent is Dioxane and H 2 O is mixed in a volume ratio of 60 to 75:1.

[0080] Furthermore, in reaction equation 1, the intermediate It is prepared by reaction equation 3:

[0081] Reaction equation 3:

[0082]

[0083] In reaction equation 2, the intermediate It is prepared by reaction equation 4:

[0084] Reaction equation 4:

[0085]

[0086] In reaction equations 3 to 4, preferably, the reaction temperature is 100±2°C; and / or, the reaction time is 11 to 13 hours; and / or, the main catalyst 2 is Pd(dppf) 2 Cl 2 , the auxiliary catalyst 2 is KOAc; and / or, the reaction solvent is Dioxane.

[0087] Furthermore, in reaction equation 3, the intermediate It is prepared by reaction equation 5:

[0088] Reaction equation 5:

[0089]

[0090] Furthermore, in reaction equation 4, the intermediate It is prepared by reaction equation 6:

[0091] Reaction equation 6:

[0092]

[0093] In reaction equations 5 to 6, preferably, the reaction temperature is 60±2° C.; and / or, the reaction time is 3 to 5 h; and / or, the catalyst is NaH; and / or, the reaction solvent is DMF.

[0094] The present invention is further described in detail below using Compound 1, Compound 5 and Compound 7 as examples, which are intended to explain the present invention rather than to limit it.

[0095] Example 1

[0096] The preparation of the DAD molecule modified with a carbazole derivative having the structure shown in compound 1 is as follows:

[0097]

[0098] The first step is to add 2-bromocarbazole (492 mg, 2.0 mmol), sodium hydride (60%, 120 mg, 3.0 mmol) and anhydrous N, N-dimethylformamide (3.0 mL) to a 50 mL round-bottom flask, stir at 60 ° C for 20 min under a nitrogen environment, then dissolve 1-bromo-2-hexyldecane (672 mg, 2.2 mmol) in anhydrous N, N-dimethylformamide (1.0 mL), continue to react at 60 ° C for 4 h, and then dilute with dichloromethane (30 mL). Add distilled water, separate the organic layer, wash three times with water (30 mL), dry with anhydrous sodium sulfate, concentrate in vacuo, spin dry and pass through a column (200-300 mesh silica gel column, petroleum ether / dichloromethane, 10 / 1, v / v). The obtained product is a colorless oily substance (866 mg, yield 92%, compound 1'). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance are as follows: Figure 1 and Figure 2 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ7.96(d,J=7.6,1H),7.83(d,J=8.2,1H),7.42(d,J=1.6,1H),7.40-7.36(m,1H),7.28(d,J=8.2 1H),7.23(dd,J=8.2,1.6,1H),7.16-7.13(m,1H),3.99(d,J=7.5,2H),2.06-1.96(m,1H),1.29-1.12(m,24H),0.81-0.75(m,6H). 13 C NMR (101 MHz, CDCl 3 )δ141.8,141.0,126.0,122.3,121.9,121.7,121.4,120.3,119.3,119.2,112.0,109.2,47.8,37. 8,31.9,31.8,31.8,30.0,29.6,29.5,29.3,26.5,26.5,22.7,22.7,14.2,14.1.HR-ESIMS(m / z)[M] + Calculate for C 28 H 40 BrN 469.2339,found 469.2341.

[0099] In the second step, compound 5' (592 mg, 1.26 mmol), catalyst [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (51.2 mg, 0.07 mmol), diboronic acid pinacol ester (384 mg, 1.51 mmol) and potassium acetate (371 mg, 3.78 mmol.), and 5 mL 1,4-dioxane were added to a 50 mL Schlenk tube. The reactants were refluxed and stirred for 12 h under a nitrogen environment. Water (20 mL) was added to terminate the reaction, and the mixture was extracted with dichloromethane three times (20 mL×3). The extract was dried and filtered over anhydrous sodium sulfate, concentrated in vacuo, and dried by column (200-300 mesh silica gel column, dichloromethane / methanol, 20 / 1, v / v). The product was a colorless oily substance (515 mg, yield 79%, compound 1"). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance were as follows: Figure 3 and Figure 4 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ8.06-7.99(m,2H),7.79(s,1H),7.60(dd,J=7.8,0.6,1H),7.41-7.35(m,1H),7.32-7.28(m,1H),7.16- 7.10(m,1H),4.12(d,J=7.5,2H),2.13-2.03(m,1H),1.31(s,12H),1.27-1.12(m,24H),0.81-0.76(m,6H). 13 C NMR (101 MHz, CDCl 3 )δ140.3,139.5,133.7,125.0,124.2,123.8,121.6,119.7,118.5,117.6,114.4,108.1,82.7,46.5,36. 8,30.8,30.8,30.7,30.7,28.9,28.6,28.5,28.2,25.5,25.4,23.9,23.8,21.6,21.6,13.1,13.1.HR-ESI MS(m / z)[M+H] + Calculate for C 34 H 53 BNO 2 518.4164, found 518.4168.

[0100] Step 3: Freeze the solvent 1,4-dioxane (3 mL) and 1 drop of water with liquid nitrogen, and then heat to liquid under vacuum. Add 4,8-bis(5-bromo-3-hexyl 2-thienyl)-2λ4δ2-benzo[1,2-c:4,5-c']bis[1,2,5]thiazole (53.0 mg, 0.077 mmol), compound 2' (80.2 mg, 0.155 mmol), tetrakis(triphenylphosphine)palladium (8.90 mg, 0.0077 mmol) and potassium carbonate (42.8 mg, 0.31 mmol) to a 10 mL Schlenk tube and replace nitrogen three times. Then add the solvent to the tube and replace nitrogen three times. Heat the reaction mixture to 110°C and stir overnight. After the reaction was completed as determined by thin layer chromatography, the product was dissolved in dichloromethane, washed with saturated brine (50 mL) and water (30 mL × 2), the organic phase was collected, dried over anhydrous sodium sulfate, concentrated in vacuo, and passed through a column (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v) to dryness. The product was obtained as a dark green solid (63.4 mg, yield 63%, compound 1). The results of H NMR and C NMR were as follows: Figure 5 and Figure 6 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ8.06-8.00(m,4H),7.64-7.61(m,2H),7.55(dd,J=8.2,1.4,2H),7.48(s,2H),7.42-7.36(m,2H),7.32(d,J=8.2,2H),7.18-7.13(m,2H), 4.13(d,J=7.4,4H),2.62-2.53(m,4H),2.15-2.04(m,2H),1.65-1.59 (m,4H),1.31-1.24(m,12H),1.19-1.08(m,40H),0.78-0.68(m,18H). 13 C NMR (101 MHz, CDCl 3 )δ152.3,147.4,144.7,140.6,140.3,130.7,127.6,124.8,124.5,121 .6,121.6,119.6,119.3,118.0,116.5,115.2,108.0,105.3,52.4,46.7 ,37.0,31.0,30.8,30.6,30.5,29.5,29.3,28.9,28.6,28.5,28.2,28.2,25.6,21.6,21.6,21.5,13.1,13.0,13.0,10.4.HR-ESIMS(m / z)[M+H] +Calculate for C 82 H 109 N 6 S 4 1305.7591, found1305.7582.

[0101] Example 2

[0102] The preparation of the DAD molecule modified with a carbazole derivative having the structure shown in compound 5 is as follows:

[0103]

[0104] The first step is to add 2-bromo-7-methoxy-9H-carbazole (552 mg, 2.0 mmol), sodium hydride (60%, 120 mg, 3.0 mmol) and anhydrous N, N-dimethylformamide (3.0 mL) to a 50 mL round-bottom flask, stir at 60 ° C for 20 minutes under nitrogen environment, then dissolve 1-bromo-2-hexyldecane (672 mg, 2.2 mmol) in anhydrous N, N-dimethylformamide (1.0 mL), continue to react at 60 ° C for 4 hours, and then dilute with dichloromethane (30 mL). Add distilled water, separate the organic layer, wash three times with water (30 mL), dry with anhydrous sodium sulfate, concentrate in vacuo, spin dry and pass through a column (200-300 mesh silica gel column, petroleum ether / dichloromethane, 10 / 1, v / v). The obtained product is a colorless oily substance (911 mg, yield 91%, compound 5'). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance are as follows: Figure 7 and Figure 8 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ7.82(d,J=8.5,1H),7.73(d,J=8.2,1H),7.36(d,J=1.6,1H),7.20(dd,J=8.2,1.6,1H),6.77(dd,J=8.5,2.2,1H ),6.74(d,J=2.2,1H),3.94(d,J=7.5,2H),3.84(s,3H),2.05-1.95(m,1H),1.28-1.11(m,24H),0.82-0.75(m,6H). 13 C NMR (101 MHz, CDCl 3)δ158.2,141.4,140.9,120.9,120.9,120.0,119.4,116.8,115.2,110.8,106.5,92.7,54.6,46.7,36.6, 30.8,30.8,30.8,30.7,28.9,28.6,28.5,28.2,25.5,25.5,21.6,21.6,13.1,13.1.HR-ESIMS(m / z)[M+H] + Calculate for C 29 H 43 BrNO500.2523, found 500.2519.

[0105] In the second step, compound 6' (796 mg, 1.59 mmol), catalyst [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (58.5 mg, 0.08 mmol), diboronic acid pinacol ester (485 mg, 1.91 mmol) and potassium acetate (468 mg, 4.77 mmol), and 5 mL 1,4-dioxane were added to a 50 mL Schlenk tube. The reactants were refluxed and stirred for 12 h under a nitrogen environment. Water (20 mL) was added to terminate the reaction, and the mixture was extracted with dichloromethane three times (20 mL×3). The extract was dried and filtered over anhydrous sodium sulfate, concentrated in vacuo, and dried by column (200-300 mesh silica gel column, dichloromethane / methanol, 20 / 1, v / v). The product was a colorless oily substance (714 mg, yield 82%, compound 5"). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance were as follows: Fig. 9 and Fig.10 The specific analysis is as follows: 1 HNMR (400MHz, CDCl 3 )δ7.89(d,J=7.8,1H),7.87-7.84(m,1H),7.73(s,1H),7.57(dd,J=7.8,0.8,1H),6.74-6.71( m,2H),4.03(d,J=7.4,2H),3.80(s,3H),1.29(s,12H),1.24-1.11(m,24H),0.80-0.73(m,6H). 13 C NMR (101 MHz, CDCl 3)δ158.3,141.7,139.7,133.7,124.5,124.1,120.4,117.6,115.6,114.1,106.1,92.4,82.6,54.5,46.4,36.6,30 .8,30.8,30.7,28.9,28.7,28.6,28.5,28.2,25.5,25.4,23.9,23.8,21.6,21.6,13.1,13.1.HR-ESIMS(m / z)[M+H] + Calculate for C 35 H 55 BNO 3 548.4270, found 548.4269.

[0106] Step 3: Freeze the solvent 1,4-dioxane (3 mL) and 1 drop of water with liquid nitrogen, and then heat to liquid under vacuum. Add 4,8-bis(5-bromo-3-hexyl 2-thienyl)-2λ4δ2-benzo[1,2-c:4,5-c']bis[1,2,5]thiazole (53.0 mg, 0.077 mmol), compound 3' (84.9 mg, 0.155 mmol), tetrakis(triphenylphosphine)palladium (8.90 mg, 0.0077 mmol) and potassium carbonate (42.8 mg, 0.31 mmol) to a 10 mL Schlenk tube and replace nitrogen three times. Then add the solvent to the tube and replace nitrogen three times. Heat the reaction mixture to 110°C and stir overnight. After the reaction was completed as determined by thin layer chromatography, the product was dissolved in dichloromethane, washed with saturated brine (50 mL) and water (30 mL × 2), the organic phase was collected, dried over anhydrous sodium sulfate, concentrated in vacuo, and passed through a column (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v) to dryness. The obtained product was a dark green solid (63 mg, yield 60%, compound 5). The results of H NMR and C NMR were as follows: Fig.11 and Fig.12 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3)δ7.93(d,J=8.0,2H),7.88(d,J=9.1,2H),7.58(d,J=1.5,2H),7.52(dd,J=8.0,1.5,2H),7.45(s,2H),6.81-6.76(m,4H),4.08(d,J=7.3, 4H),3.87(s,6H),2.61-2.52(m,4H),2.08(d,J=8.0,2H),1.65-1.57(m,4H),1.32-1.27(m,12H),1.17-1.08(m,40H),0.78-0.68(m,18H). 13 C NMR (101 MHz, CDCl 3 )δ158.1,152.3,147.6,144.7,142.0,140.5,129.6,127.4,124.3,121. 9,120.0,118.7,116.6,115.6,115.2,106.3,105.2,92.6,54.6,46.7,36 .8,31.0,30.8,30.5,29.5,29.3,28.9,28.7,28.6,28.6,28.5,28.2,28 .2,25.7,23.9,21.6,21.6,21.5,13.1,13.0,13.0.HR-ESIMS(m / z)[M+H] + calcdfor C 84 H 113 N 6 O 2 S 4 1365.7802, found 1365.7843.

[0107] Example 3

[0108] The preparation of the DAD molecule modified with a carbazole derivative having the structure shown in compound 7 is as follows:

[0109]

[0110] The first step is to add 9-bromo-7H-benzo[c]carbazole (592mg, 2.0mmol), sodium hydride (60%, 120mg, 3.0mmol) and anhydrous N,N-dimethylformamide (3.0mL) to a 50mL round-bottom flask, stir at 60°C for 20min under nitrogen environment, then dissolve 1-bromo-2-hexyldecane (672mg, 2.2mmol) in anhydrous N,N-dimethylformamide (1.0mL), continue to react at 60°C for 4h, and then dilute with dichloromethane (30mL). Add distilled water, separate the organic layer, wash three times with water (30mL), dry with anhydrous sodium sulfate, concentrate in vacuo, spin dry and pass through a column (200-300 mesh silica gel column, petroleum ether / dichloromethane, 10 / 1, v / v). The obtained product is a colorless oily substance (875mg, yield 84%, compound 7'). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance are as follows: Fig.13 and Fig.14 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ8.53(d,J=8.2,1H),8.22(d,J=8.5,1H),7.86(d,J=8.2,1H),7.72(d,J=8.5,1H),7.60-7.54(m,1H),7.44(d,J=1.7,1H ),7.36(d,J=8.6,2H),7.34-7.29(m,1H),3.92(d,J=7.5,2H),1.99-1.87(m,1H),1.21-1.03(m,24H),0.79-0.71(m,6H). 13 C NMR (101 MHz, CDCl 3 )δ139.4,137.5,128.6,128.1,127.9,126.4,125.9,122.0,121.9,121.6,121.1,116.5,113.3,111.4,109.9 ,46.5,37.0,30.8,30.7,30.7,30.6,28.8,28.5,28.4,28.2,25.4,21.6,21.6,13.1,13.0.HR-ESIMS(m / z)[M] + Calculate for C 32 H 42 BrN 519.2495, found 519.2498.

[0111] In the second step, compound 3-3 (828 mg, 1.59 mmol), catalyst [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (58.5 mg, 0.08 mmol), diboronic acid pinacol ester (485 mg, 1.91 mmol) and potassium acetate (468 mg, 4.77 mmol), and 5 mL 1,4-dioxane were added to a 50 mL Schlenk tube. The reactants were refluxed and stirred for 12 h under a nitrogen environment. Water (20 mL) was added to terminate the reaction, and the mixture was extracted with dichloromethane three times (20 mL×3). The extract was dried and filtered over anhydrous sodium sulfate, concentrated in vacuo, and dried by column (200-300 mesh silica gel column, dichloromethane / methanol, 20 / 1, v / v). The product was a colorless oily substance (695 mg, yield 77%, compound 7"). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance were as follows: Fig.15 and Fig.16 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ8.74(d,J=8.4,1H),8.50(d,J=8.0,1H),7.95(s,1H),7.92(d,J=8.4,1H),7.82(d,J=8.9,1H),7.74(d,J=8.0,1H),7.66-7.60(m,1H ),7.56(d,J=8.9,1H),7.41-7.36(m,1H),4.28(d,J=7.5,2H),2.16-2.05(m,1H),1.34(s,12H),1.27-1.10(m,24H),0.79-0.76(m,6H). 13 C NMR (101 MHz, CDCl 3 )δ138.3,138.0,133.7,129.1,128.1,127.7,126.6,125.9,124.7,124.6,122.2,121.8,120.2,115.2,113.6,110.2,82.7, 46.5,37.2,30.8,30.8,30.7,28.9,28.6,28.5,28.2,25.5,25.4,23.9,21.6,21.6,13.1,13.1,13.0.HR-ESIMS(m / z)[M+H] + Calculate for C 38 H 55 BNO 2 568.4320, found 568.4319.

[0112] Step 3: Freeze the solvent 1,4-dioxane (3 mL) and 1 drop of water with liquid nitrogen, and then heat to liquid under vacuum. Add 4,8-bis(5-bromo-3-hexyl 2-thienyl)-2λ4δ2-benzo[1,2-c:4,5-c']bis[1,2,5]thiazole (53.0 mg, 0.077 mmol), compound 3-6 (88.0 mg, 0.155 mmol), tetrakis(triphenylphosphine)palladium (8.90 mg, 0.0077 mmol) and potassium carbonate (42.8 mg, 0.31 mmol) to a 10 mL Schlenk tube and replace nitrogen three times. Then add the solvent to the tube and replace nitrogen three times. Heat the reaction mixture to 110°C and stir overnight. After the reaction was completed as determined by thin layer chromatography, the product was dissolved in dichloromethane, washed with saturated brine (50 mL) and water (30 mL × 2), the organic phase was collected, dried over anhydrous sodium sulfate, concentrated in vacuo, and passed through a column (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v) to dryness. The product was obtained as a dark green solid (75.8 mg, yield 70%, compound 7). The results of H NMR and C NMR were as follows: Fig.17 and Fig.18 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3 )δ8.80(d,J=8.2,2H),8.60(d,J=8.4,2H),8.02(dd,J=8.2,1.3,2H),7.91(d,J=9.0,2 H),7.85(d,J=1.6,2H),7.77(dd,J=8.2,1.6,2H),7.75-7.70(m,2H),7.65(d,J=8.9,2H ),7.60(s,2H),7.52-7.46(m,2H),4.36(d,J=7.4,4H),2.72-2.64(m,4H),2.24-2.17( m,2H),1.76-1.67(m,4H),1.42-1.32(m,12H),1.24-1.16(m,40H),0.83-0.75(m,18H). 13 C NMR (101 MHz, CDCl 3)δ153.5,148.6,145.9,140.3,139.4,130.3,130.0,129.4,129.1,128. 7,127.5,127.1,125.6,123.4,123.3,123.1,122.4,118.6,116.4,115.0 ,111.2,107.0,47.9,38.6,32.1,31.9,31.7,30.7,30.5,30.0,29.8,29 .8,29.6,29.4,26.8,22.8,22.7,22.7,14.2,14.2.HR-ESIMS(m / z)[M+H] + Calculate for C 90 H 113 N 6 S 4 1405.7904, found 1405.7920.

[0113] Example 4

[0114] The preparation of the alkylfluorene-modified DAD molecule TBTF is as follows:

[0115]

[0116] The solvent 1,4-dioxane (3 mL) and 1 drop of water were frozen with liquid nitrogen and then heated to liquid under vacuum. 4,8-bis(5-bromo-3-hexyl-2-thienyl)-2λ4δ2-benzo[1,2-c:4,5-c']bis[1,2,5]thiazole (53.0 mg, 0.077 mmol), compound 2-(9,9-dioctyl-9H-fluorene-2-yl)-4,4,5,5-tetramethyl-1,3,2-diborane (80.1 mg, 0.155 mmol), tetrakis(triphenylphosphine)palladium (8.90 mg, 0.0077 mmol) and potassium carbonate (42.8 mg, 0.31 mmol) were added to a 10 mL Schlenk tube and replaced with nitrogen three times. Then the solvent was added to the tube and replaced with nitrogen three times. The reaction mixture was heated to 110°C and stirred overnight. After the reaction was completed as determined by thin layer chromatography, the product was dissolved in dichloromethane, washed with saturated brine (50 mL) and water (30 mL × 2), the organic phase was collected, dried over anhydrous sodium sulfate, concentrated in vacuo, and passed through a column (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v) to dryness. The product was obtained as a dark green solid (60.2 mg, yield 60%). The results of H NMR and C NMR were as follows: Fig.19 and Fig. 20 The specific analysis is as follows: 1 H NMR (400 MHz, CDCl 3).δ7.66-7.62(m,6H),7.59-7.57(m,2H),7.45(s,2H),7.29-7.23(m,6H),2.58-2.52(m,4H),1.97-1.90( m,8H),1.64-1.57(m,4H),1.12-0.97(m,52H),0.73(t,J=7.1,12H),0.70-0.66(m,6H),0.62-0.52(m,8H). 13 C NMR (101 MHz, CDCl 3 )δ152.3,150.4,149.9,146.8,144.8,140.1,139.6,132.0,127.4,126.2,125.8,124.4,123.8,121.8,119.2,119.0,1 18.7,115.2,54.2,39.5,30.8,30.5,29.5,29.3,29.0,28.2,28.2,22.8,21.6,21.5,13.0,13.0.HR-ESIMS(m / z)[M+H] + Calculate for C 84 H 110 N 4 S 4 1303.7686, found 1303.7692.

[0117] Example 5

[0118] Preparation of nanoparticles

[0119] The above-mentioned carbazole and its derivatives modified small molecules (1 mg / mL, 300 μL) and DSPE-PEG2000 (2 mg / mL, 300 μL) in anhydrous THF were mixed, poured into 10 mL of ultrapure water under ultrasonic conditions, and then ultrasonicated for 2 minutes. The solution was concentrated under nitrogen, filtered with a 0.22 μm PES filter, and stored at 4°C for later use.

[0120] Folic acid (FA) functional nanoparticle molecules (1 mg / mL, 300 μL), DSPE-PEG2000 (2 mg / mL, 200 μL) and DSPE-PEG2000-FA (2 mg / mL, 100 μL) were mixed in anhydrous THF, poured into 10 mL of ultrapure water under ultrasonic conditions, and then ultrasonicated for 2 minutes. The solution was concentrated under nitrogen, filtered with a 0.22 μm PES filter, and stored at 4°C for later use.

[0121] Using the nanoreprecipitation method, small molecules fold and twist the main chain through hydrophobic interactions to form nanoparticles. The size of the final nanoparticles can be adjusted by controlling the concentration ratio of small molecules and amphiphilic liposomes. The particle size and morphology of these nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM), such as Fig.21 The size of all nanoparticles is about 20-30 nm, and the diameter is about 10 nm as determined by transmission electron microscopy (TEM).

[0122] Example 6

[0123] Cell culture and toxicity analysis

[0124] All cell lines were provided by American Type Culture Collection (ATCC, Manassas, VA, USA). MCF-7 cells were cultured in Dulbecco's Modified Eagle medium (DMEM) supplemented with 10% heat-inactivated fetal bovine serum (FBS); 4T1 cells were cultured in RPMI 1640 supplemented with 10% heat-inactivated fetal bovine serum. The culture conditions were 5% CO 2 , 37°C. When the cells grow to 90% confluence, trypsin is used to digest the cells for later experiments.

[0125] The CCK8 method was used to evaluate the effect of nanoparticles on the metabolic activity of MCF-7 cells and 4T1 cells. 4 Cells / mL) were inoculated into each well of a 96-well plate and cultured overnight. The old culture medium was replaced with DMEM / RMPI 1640 culture medium containing different nanoparticle concentrations (10, 5, 2.5, 0.1 μg / mL). The control group did not add nanoparticles and incubated at 37°C for 24 hours. The old culture medium was discarded and the cells were washed with pH = 7.2 phosphate buffer (PBS). Fresh DMEM / RMPI 1640 culture medium (90 μL) and 10 μL CCK8 solution (kit stock solution) were then added to each well and allowed to stand at 37°C for 4 hours. The enzyme dehydrogenase in the living cells was oxidized to orange by this kit, and then the absorbance of each well at a wavelength of 450 nm was measured using a microplate reader (TECAN, Infinite M200, Germany). The cell growth viability was calculated using the following formula:

[0126] Viability (%) = average absorbance of the experimental group / average absorbance of the control group (1-1).

[0127] like Fig. 22 , Fig.23As shown, after 48 h, TBTF, TBTC-1 (compound 1), TBTC-2 (compound 5), and TBTC-3 (compound 7) were non-toxic and cell viability was not affected.

[0128] Example 7

[0129] Molar extinction coefficient calculation

[0130] According to the Lambert-Beer law, the absorbance and molar concentration of the solution were linearly fitted, and the molar extinction coefficient was calculated as follows:

[0131] A = εcl(1-2);

[0132] In formula (1-2), A is the maximum absorption wavelength or the absorbance at 808 nm, ε is the molar extinction coefficient related to the intrinsic properties of the compound, l is the absorption thickness of the light path, and c is the concentration of the solution. The molar concentration of small molecules and nanoparticles is calculated by dividing the molar concentration of the corresponding compound by the volume of the solution, and the absorbance is measured using solutions of different concentrations.

[0133] Then the molar extinction coefficients of all small molecules in tetrahydrofuran and their nanoparticles prepared from small molecules in water were evaluated. It can be clearly seen that the introduction of carbazole increases the molar extinction coefficient of DAD molecules (see Table 1), and the molar extinction coefficients (ε1) at the peak wavelength of TBTC-1 and TBTC-2 are higher than that of TBTF, and even the molecule TBTC-3 with a larger conjugation degree has a coefficient similar to that of TBTF. After being encapsulated by nanoparticles, the molar extinction coefficients of all molecules inevitably decrease, but except for TBTC-2, the molar extinction coefficients of the remaining molecules remain at 10 4 cm -1 M -1 Although the introduction of methoxy groups enhances the donor ability of carbazole and causes a red shift in the absorption and emission spectra, the freely rotating methoxy groups may destroy the planarity of the entire molecule in the aggregated state, which is the reason for the low molar extinction coefficient of TBTC-2 nanoparticles.

[0134] Table 1 Optical properties of small molecules and nanoparticles

[0135]

[0136] Note: In Table 1, ε 1 is the molar extinction coefficient at the peak wavelength of the absorption spectrum; ε 2 is the molar extinction coefficient at a wavelength of 808 nm; QY1 and QY2 are the quantum yields at the fluorescence wavelength range of 850-1500 nm and 1000-1500 nm, respectively.

[0137] Example 8

[0138] Quantum yield calculation

[0139] In this example, we used a relative strategy to measure the quantum yield (QY). The standard dye IR-26 was used as a reference to measure QY. The calculation formula is

[0140]

[0141] where Φ X is the QY of nanoparticles in water or the QY of small molecules in tetrahydrofuran, Φ ST is the quantum yield of IR-26 (approximately 0.5% in ethylene dichloride), Grad X is the linear fitting slope of the emission spectrum area of ​​nanoparticles (850-1500nm or 1000-1500nm) or small molecules (850-1500nm or 1000-1500nm) and the absorbance at 808nm, Φ ST is the linear fitting slope of the emission spectrum area of ​​IR-26 (1000-1500nm) and the absorbance at 808nm, η X and η ST is the refractive index of each solvent (water: 1.333, tetrahydrofuran: 1.465, dichloroethane: 1.4167).

[0142] The quantum yield of the molecule was calculated with IR26 (0.5% in dichloroethane) as a reference. As shown in Table 1, although the QY of TBTC-1 in organic solvents is similar to that of TBTF, the quantum yield of TBTC-1 nanoparticles in aqueous solution is significantly higher than that of TBTF nanoparticles, proving that the degree of fluorescence quenching in TBTC-1 nanoparticles is lower than that in TBTF nanoparticles, and the introduction of carbazole groups has obvious advantages over the classic fluorene structure. The QY of small molecules TBTC-2 and TBTC-3 is low due to the longer conjugated structure, but the QY of TBTC-3 nanoparticles in water is acceptable because the degree of fluorescence quenching of TBTC-3 in the aggregated state is the smallest among these nanoparticles, and the red shift of the emission spectrum makes the QY in the range after 1000nm relatively high.

[0143] Example 9

[0144] Brightness calculation

[0145] The overall brightness is determined by the extinction coefficient and the quantum yield. Here, the quantum efficiency (QE) is defined as their multiplication. Considering that the excitation wavelength commonly used in actual imaging is 808nm, in order to obtain better imaging effects, it is best to collect the emitted fluorescence in the NIR-II range. Therefore, QE is obtained by ε2×QY2 in the discussion (Table 1). Among the four nanoparticles, TBTC-3 nanoparticles have the highest brightness (in Fig.24 TBTC-3 has the largest area) and may be the most promising material for in vivo NIR-II imaging.

[0146] Example 10

[0147] Vascular imaging

[0148] Vascular imaging was performed using BALB / c nude mice, which were injected with 50 μL of various nanoparticle aqueous solutions (200 μg / mL) through the tail vein and immediately placed in a small animal in vivo imager to collect images. All images were collected under 808 nm excitation and different filter combinations. The camera used in the small animal in vivo imager is an InGaAs detector. The imaging system is a VanGogh IGS1000 near-infrared second-zone imaging system, and the excitation light source is an 808 nm wavelength fiber-coupled laser with a laser output power density of 0.2 W cm -2 , flux = 40 mW cm -2 .

[0149] Vascular imaging was performed on mice to confirm the in vivo NIR-II imaging performance of these nanoparticles. After intravenous injection, the hind limb blood vessels of nude mice were observed under the small animal NIR-II imaging system. Fig.25 As shown in the figure, although the emission signals of these four nanoparticles are similar after a wavelength of 1000nm, there are significant differences in performance under a 1300nm long-wave pass filter. In this range, the fluorescence intensity of TBTF and TBTC-1 nanoparticles is low and the signal cannot be clearly distinguished from the background. Fig.26 As shown, TBTC-2 and TBTC-3 nanoparticles have strong NIR-II fluorescence emission above 1300nm due to the red shift of the spectrum, and the signal-to-noise ratio (SBR) is higher, indicating that they have advantages in in vivo imaging at longer wavelengths. In particular, TBTC-3 nanoparticles with the highest brightness have the best effect on hindlimb vascular imaging when the SBR is greater than 2.

[0150] Embodiment 11

[0151] Targeted tumor and metastasis imaging

[0152] In the experiment of establishing tumor-bearing mouse model, female BLAB / c mice were used to prepare cell suspension with 4T1 cells after elimination. The concentration was 1×10 7cells / mL. 100uL 4T1 cells were injected into the mammary fat pad of BALB / c female mice as the orthotopic location of breast cancer. One week later, cell-derived xenografts were established. At the same time, due to the high invasiveness of 4T1 cells, distant metastasis occurred. For tumor imaging, mice injected with cancer cells one week after injection were selected. 50μL of folic acid-functionalized TBTC-3 nanoparticle aqueous solution (200μg / mL) were injected through the tail vein, and images were collected at the corresponding time points. The camera used for the small animal in vivo imager is an InGaAs detector. The imaging system is a VanGogh IGS1000 near-infrared second-zone imaging system, the excitation light source is a 808nm wavelength fiber-coupled laser, and the laser output power density = 0.2W cm -2 , flux = 40 mW cm -2 Considering the balance between fluorescence intensity and resolution, an 1100lp filter was used for imaging.

[0153] Based on the excellent NIR-II fluorescence performance of TBTC-3 nanoparticles in vascular imaging, its application in tumor and metastasis imaging was explored. FA-functionalized TBTC-3 nanoparticles were intravenously injected into mice, and NIR-II images were taken at different time points after injection. Fig. 27 As shown in A, the signal can be clearly detected in the tumor 2h after injection, and the SBR reaches the maximum value 12h after injection. At the same time, the mice were dissected to study the distribution of nanoparticles. Fig.28 As shown in the figure, nanoparticles are mainly distributed in the liver, spleen and tumors, and no signal is found in the heart, kidney and lung, suggesting that they are eliminated through the hepatobiliary metabolic pathway. Fig.29 As shown in the figure, in the case of unmodified FA targeting unit, TBTC-3 nanoparticles were poorly enriched in mouse breast tumors, indicating the importance of FA in targeted breast cancer imaging. After 24h intravenous injection, the NIR-II fluorescence intensity in mice decreased. The NIR-II signal was unevenly distributed in the tumor, and the signal was clearer when using the 1100lp filter than when using the 1000lp filter ( Fig. 27 B). Draw lines to mark the signal strength read from these two images ( Fig. 27 C) indicates that collecting signals in the range after 1100 nm can provide more accurate insights into details, prompting us to further image metastases in this fluorescence range.

[0154] To establish a tumor metastasis model, we injected 4T1 cells intravenously into BALB / c female mice. One week later, distant metastasis occurred due to the highly invasive nature of 4T1 cells. FA-functionalized TBTC-3 nanoparticles were injected intravenously into mice, and then the mice were imaged under the NIR-II imaging system. After 8 h, NIR-II signals were observed in some parts (such as Fig.30A), indicating that nanoparticles are enriched in these tissues, possibly indicating the presence of cancer cell metastasis. In this case, the mice were sacrificed and their skin removed, allowing NIR-II imaging to more clearly show their distribution. Fig.30 As shown in B, in addition to the bright liver and spleen, there are several small tissues with NIR-II emission signals, including an axillary tissue (marked as 1), two mouse chest tissues (2 and 3), two peritoneal tissues (4 and 6) and an intestinal tissue (5). It should be noted that since the surgery was not performed under a real-time fluorescence navigation system, some healthy tissues were included in the resected tissues. These tissues were resected and fixed with 10% formalin, and then paraffin-embedded tissue sections were made for H&E staining analysis. As expected, cancer cells can be found in all tissues, and the enlarged pictures of the cancer cell invasion areas are shown in Figure 1. Fig.30 C is shown on the right. In fact, because these metastases are less than 2 mm in diameter and some cancer cells are distributed in deep tissues, they are difficult to detect with traditional surgical methods. However, through NIR-II imaging of bright TBTC-3 nanoparticles, these metastases can be clearly and accurately observed, which illustrates the advantage of high-brightness materials in the NIR-II window.

[0155] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A DAD molecule modified with a carbazole derivative, characterized in that: The DAD molecule modified with the carbazole derivative has the general formula shown in formula (I): in: The dotted line between R2 and R3 indicates that there is no chemical bond between R2 and R3, or that the chemical bond between R2 and R3 is a single bond or a double bond; R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy; When there is no chemical bond between R2 and R3, R2 and R3 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy; R4 does not represent any group; When there is a chemical bond between R2 and R3, R2, R3 and the C atom connected thereto together form a 5-7 membered heterocyclic group, aromatic ring group or heteroaryl group; R2, R3 are independently selected from: H, CH, N, NH, CR5, NR6, CHR7, C(R8)2; R4 is selected from: H, C1-C6 alkyl, C1-C6 alkoxy; R5, R6, R7, R8 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy.

2. The DAD molecule modified with a carbazole derivative according to claim 1, characterized in that: The DAD molecule modified with the carbazole derivative has the general formula shown in formula (II): in: R1 and R2 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy.

3. The DAD molecule modified with a carbazole derivative according to claim 1, characterized in that: The DAD molecule modified with the carbazole derivative has the general formula shown in formula (III): in: R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy; R4 is selected from: H, C1-C6 alkyl, C1-C6 alkoxy.

4. The DAD molecule modified with a carbazole derivative according to claim 3, characterized in that: R4 is selected from: H.

5. The DAD molecule modified with a carbazole derivative according to claim 1, characterized in that: The DAD molecule modified with the carbazole derivative is selected from the following compounds:

6. Use of the DAD molecule modified with the carbazole derivative according to any one of claims 1 to 5 in the preparation of functional nanoparticles.

7. A method for preparing functional nanoparticles, characterized in that: The steps include: Step 1, dispersing the DAD molecule modified with the carbazole derivative according to any one of claims 1 to 5 in a solvent, adding DSPE-PEG2000 to mix, and adding the mixture into ultrapure water for ultrasonic dispersion; Step 2, removing the solvent in the system after ultrasonic dispersion and separating the solid therein to obtain the functional nanoparticles.

8. The preparation method according to claim 7, characterized in that: In the step 1, the mass ratio of the DAD molecule modified with the carbazole derivative to DSPE-PEG2000 is 1:1-10; and / or, the solvent is a polar organic solvent, preferably an alkyl ether, a low carboxylic acid ester, an alkyl alcohol, or an aromatic hydrocarbon containing a benzene ring; and / or, in the step 2, a 0.22 μm PES filter is used to separate the solid.

9. Functional nanoparticles obtained by the preparation method according to claim 7 or 8.

10. Use of the functional nanoparticles according to claim 9 in preparing luminescent materials.

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