Carbazole derivative-modified DAD molecules and their applications

Abstract

The present invention provides a D-A-D molecule modified with a carbazole derivative and its application. The D-A-D molecule modified with a carbazole derivative has the general formula shown in formula (I): #imgabs0# The D-A-D molecule has the characteristic of high brightness. Compared with the existing S-D-A-D-S molecule with an alkyl-substituted fluorene structure, it has better imaging effect in the near-infrared second zone window and can be used for imaging various lesions in the body, especially micro-lesions.

Description

Technical Field

[0001] The present 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-structured small molecule dye CH1055 with NIR-II imaging characteristics using triphenylamine as the donor and BBTD as the 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, many reports have been conducted 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 backbone, reducing intermolecular interactions and increasing intermolecular distances, which in turn improves the fluorescence QY to a certain extent. PEGylated H1 exhibits excellent biocompatibility and clearance efficiency, achieving 90% renal clearance within hours after injection. Jiang et al. designed and synthesized the DAD-structured fluorophores TPB-AM, TPB-BAM, and TPBAZO using amino-, tert-butylcarbonyl-, and benzoazole-functionalized triphenylamine as electron donors, respectively. [2] TPB-AZO exhibits a blue-shifted emission peak at 909 nm, but with a high QY of 21.59%. The red-shifted emission and weak QY of TPB-AM and TPB-BAM are attributed to the amino group in the donor moiety, which enhances the ICT effect. Ma et al. designed the molecule FM1210 using BSBT as an acceptor and compared it with the molecule CF1065 using BBTD as an acceptor. FM1210 exhibited a significant red-shift of 145 nm, while the introduction of Se had little effect on the 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 molecular ends to increase quantum yield has become a common approach in the field, such as alkyl-substituted fluorenes. In 2017, Dai et al. designed the first NIR-II fluorophore IR-FE with an SDADS structure, using BBTD as the acceptor, 3,4-ethylenedioxythiophene (EDOT) as the donor, and dialkylfluorene as the shielding unit. IR-FE exhibited a QY of up to 31% in toluene solution. [4]Furthermore, PEGylated IR-FEP exhibited enhanced fluorescence in water, with a QY of 2.0%. Dai et al. further synthesized the fluorophore IR-FTA, which has an S-D2-D1-A-D1-D2-S structure, based on IR-FE, using octylthiophene as the first donor and thiophene as the second donor. The multiple donors increased the length of the conjugate, while octylthiophene increased the dihedral angle between the donor and acceptor and the overall hydrophobicity, enhancing the QY. PEGylated IR-FTAP exhibited an emission peak at 1048 nm under 808 nm laser excitation, with a QY in water of 5.3%. [5]

[0004] However, most of these DAD molecules obtained using these techniques require further encapsulation and modification with amphiphilic polymers to achieve the required water solubility for in vivo applications. This also brings with it a series of problems, such as aggregation-induced quenching and blue shifts in absorption and emission, which can affect the NIR-II luminescence properties of the fluorescent dye. Therefore, to achieve better practical imaging results, it is necessary to further optimize the DAD molecular structure to improve the photophysical parameters after encapsulation 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.

[0009] [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.

[0010] [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

[0011] In view of this, and in response to 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 good imaging effect in the near-infrared second zone window.

[0012] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0013] 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 the general formula (I):

[0014] in:

[0015] 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;

[0016] R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy;

[0017] When there is no chemical bond between R2 and R3, R2 and R3 are independently selected from the group consisting of: H, halogen, C1-C6 alkyl, C1-C6 alkoxy; R4 does not represent any group;

[0018] 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.

[0019] Preferably, the DAD molecule modified with the carbazole derivative has the general formula shown in formula (II):

[0020] in:

[0021] R1 and R2 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy.

[0022] Preferably, the DAD molecule modified with the carbazole derivative has the general formula shown in formula (III):

[0023] in:

[0024] R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy;

[0025] R4 is selected from the group consisting of: H, C1-C6 alkyl, C1-C6 alkoxy.

[0026] Preferably, R4 is selected from: H.

[0027] Preferably, the DAD molecule modified with the carbazole derivative is selected from the following compounds:

[0028]

[0029]

[0030] 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.

[0031] In a third aspect, the present invention provides a method for preparing functional nanoparticles, comprising the following steps:

[0032] Step 1, dispersing the DAD molecules modified with the carbazole derivative described in the first aspect in a solvent, adding DSPE-PEG2000 and mixing, and adding the mixture into ultrapure water for ultrasonic dispersion;

[0033] Step 2: removing the solvent from the system after ultrasonic dispersion and separating the solid therein to obtain the functional nanoparticles.

[0034] Preferably, in step 1, the mass ratio of the carbazole derivative-modified DAD molecule 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 step 2, a 0.22 μm PES filter is used to separate the solid.

[0035] In a fourth aspect, the present invention provides functional nanoparticles obtained by the preparation method described in the third aspect.

[0036] In a fifth aspect, the present invention provides the use of the functional nanoparticles described in the fourth aspect in preparing luminescent materials.

[0037] In the present invention, the luminescent material is mainly used for vascular imaging, tumor imaging, tumor micrometastasis imaging, fluorescence navigation surgery, etc.

[0038] The beneficial effects of the present invention are:

[0039] The present invention designs and synthesizes a DAD molecule modified with a carbazole derivative. The DAD molecule has the characteristics of high brightness. Compared with the previously reported SDADS molecule with an alkyl-substituted fluorene structure (TBTF, reported in literature [5]), it has better imaging effect in the near-infrared second zone window and can be used for the imaging of various lesions in the body, especially micro-lesions. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0042] Figure 3 This is the H NMR result of compound 1" in Example 1 of the present invention.

[0043] Figure 4 This is the carbon NMR result of compound 1" in Example 1 of the present invention.

[0044] Figure 5 This is the H NMR result of compound 1 in Example 1 of the present invention.

[0045] Figure 6 This is the carbon NMR result of compound 1 in Example 1 of the present invention.

[0046] Figure 7 This is the H NMR result of compound 5' in Example 2 of the present invention.

[0047] Figure 8 This is the carbon NMR result of compound 5' in Example 2 of the present invention.

[0048] Figure 9 This is the H NMR result of compound 5" in Example 2 of the present invention.

[0049] Figure 10 This is the carbon NMR result of compound 5" in Example 2 of the present invention.

[0050] Figure 11 This is the H NMR result of compound 5 in Example 2 of the present invention.

[0051] Figure 12 This is the carbon NMR result of compound 5 in Example 2 of the present invention.

[0052] Figure 13 This is the H NMR result of compound 7' in Example 3 of the present invention.

[0053] Figure 14 This is the carbon NMR result of compound 7' in Example 3 of the present invention.

[0054] Figure 15 This is the H NMR result of compound 7" in Example 3 of the present invention.

[0055] Figure 16 This is the carbon NMR result of compound 7" in Example 3 of the present invention.

[0056] Figure 17 This is the H NMR result of compound 7 in Example 3 of the present invention.

[0057] Figure 18 This is the carbon NMR result of compound 7 in Example 3 of the present invention.

[0058] Figure 19 This is the H NMR result of the compound TBTF in Example 4 of the present invention.

[0059] Figure 20 This is the carbon NMR result of the compound TBTF in Example 4 of the present invention.

[0060] Figure 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 A. TBTF; B. TBTC-1; C. TBTC-2; D. TBTC-3 have a scale of 100 nm.

[0061] Figure 22 The changes in 4T1 cell viability 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.

[0062] Figure 23 The changes in MCF-7 cell viability after incubation with different concentrations of nanoparticles in Example 6 of the present invention for 48 hours, wherein A. TBTF; B. TBTC-1; C. TBTC-2; D. TBTC-3 nanoparticles.

[0063] Figure 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).

[0064] Figure 25This image shows imaging of nude mouse hindlimb blood vessels after intravenous injection of different nanoparticles using different wavelength filters in Example 10. Different wavelength filters: 1000 lp, 1100 lp, and 1300 lp (scale bar, 1 cm). Nanoparticle injection volume (200 μg / mL, 50 μL).

[0065] Figure 26 for Figure 25 NIR-II fluorescence intensity plot of the linear region of interest. The left side of the figure lists SBRs under different wavelength filter conditions. A. TBTF; B. TBTC-1; C. TBTC-2; D. TBTC-3.

[0066] Figure 27 Figure 11 shows targeted tumor imaging of FA-functionalized TBTC-3 nanoparticles in Example 11 of the present invention. A. NIR-II images of BALB / c mice bearing 4T1 tumors at different time points after intravenous injection of FA-functionalized TBTC-3 nanoparticles (200 μg / mL, 50 μL) using an 1100 lp filter; B. NIR-II images of the same mice 24 hours after intravenous injection of FA-functionalized TBTC-3 nanoparticles (200 μg / mL, 50 μL) using 1100 lp and 1000 lp filters; C. Fluorescence intensity plot corresponding to the linear region of interest.

[0067] Figure 28 Figure 11 shows the bright field image (Figure A) and NIR-II fluorescence image (Figure B) of the anatomical organs of 4T1 tumor-bearing BALB / c mice in Example 11 of the present invention.

[0068] Figure 29 Images 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. The injection volume of TBTC-3 nanoparticles was 200 μg / mL, 50 μL.

[0069] Figure 30 Results of imaging distal tumor metastases using 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 tissue sections; C. Bright-field view (top) and NIR-II image (bottom) of the excised tissue, along with H&E-stained images of its paraffin-embedded tissue sections (scale bar, 500 μm), and a magnified image of the cancer cell area (scale bar, 50 μm). DETAILED DESCRIPTION

[0070] In the description of the present invention, it should be noted that if 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.

[0071] The following will be combined with the accompanying 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 making creative efforts are within the scope of protection of the present invention.

[0072] In the embodiments of the present invention, the present invention provides methods for preparing DAD molecules represented by compounds 1 to 10 as examples. The scope of protection of the present invention is not limited to these 10 compounds. Compounds falling within the scope of general formula (I) can also be prepared by referring to the following preparation process. The specific reaction formulas for compounds 1 to 10 are as follows:

[0073] (1) Compounds 1 to 6 were prepared by reaction equation 1:

[0074] Reaction equation 1:

[0075]

[0076] Wherein, R1 is selected from: H, methyl, ethyl, methoxy, ethoxy; R2 is selected from: H, methyl.

[0077] (1) Compounds 7 to 10 were prepared by reaction equation 2:

[0078] Reaction equation 2:

[0079]

[0080] Wherein, R1 is selected from: H, methyl; R4 is selected from: H, methyl, methoxy.

[0081] In reaction equations 1 and 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(Ph3)4, and the auxiliary catalyst is K2CO3; and / or, the reaction solvent is a mixture of Dioxane and H2O in a volume ratio of 60 to 75:1.

[0082] Furthermore, in reaction equation 1, the intermediate It is prepared by reaction equation 3:

[0083] Reaction equation 3:

[0084]

[0085] In reaction equation 2, the intermediate It is prepared by reaction equation 4:

[0086] Reaction equation 4:

[0087]

[0088] 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 second main catalyst is Pd(dppf)2Cl2, and the second auxiliary catalyst is KOAc; and / or the reaction solvent is Dioxane.

[0089] Furthermore, in reaction equation 3, the intermediate It is prepared by reaction equation 5:

[0090] Reaction equation 5:

[0091]

[0092] Furthermore, in reaction equation 4, the intermediate It is prepared by reaction equation 6:

[0093] Reaction equation 6:

[0094]

[0095] In reaction equations 5 and 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.

[0096] 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.

[0097] Example 1

[0098] The preparation of the DAD molecule modified with a carbazole derivative having the structure shown in compound 1 is as follows:

[0099]

[0100] 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, place it under nitrogen and stir at 60 ° C for 20 min, 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). Distilled water was added, the organic layer was separated, washed three times with water (30 mL), dried over anhydrous sodium sulfate, concentrated in vacuo, and dried by column (200-300 mesh silica gel column, petroleum ether / dichloromethane, 10 / 1, v / v). The product was obtained as 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 (400MHz, CDCl3) 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 (101MHz, CDCl3) δ141.8,141.0,126.0,122.3,121.9,121.7,121.4,120.3,119.3,119.2,112.0,1 09.2,47.8,37.8,31.9,31.8,31.8,30.0,29.6,29.5,29.3,26.5,26.5,22.7,22.7,14.2,14.1.HR-ESI MS(m / z)[M] + calcd for C 28 H 40 BrN 469.2339,found 469.2341.

[0101] 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), bipyralidoborane (384 mg, 1.51 mmol) and potassium acetate (371 mg, 3.78 mmol.), and 5 mL of 1,4-dioxane were added to a 50 mL Schlenk tube. The reactants were refluxed and stirred under nitrogen for 12 h. 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 over anhydrous sodium sulfate, filtered, concentrated in vacuo, and dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 20 / 1, v / v). The product was obtained as a colorless oily substance (515 mg, yield 79%, compound 1"). The results of H NMR and C NMR were as follows: Figure 3 and Figure 4 The specific analysis is as follows: 1 H NMR (400MHz, CDCl3) 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,1 H),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 (101MHz, CDCl3) 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] + calcd for C 34 H 53 BNO2 518.4164, found 518.4168.

[0102] Step 3: The solvent 1,4-dioxane (3 mL) and one drop of water were frozen with liquid nitrogen and then heated under vacuum until liquid. 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) were added to a 10 mL Schlenk tube and the atmosphere was purged with nitrogen three times. The solvent was then added to the tube and the atmosphere was purged 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 and 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 dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v). 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 (400MHz, CDCl3) 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),7.18-7.1 3(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 (101MHz, CDCl3) δ152.3,147.4,144.7,140.6,140.3,130.7,127.6,124.8,124.5,121.6,121.6,119.6,119.3,118.0,116.5,115.2,108.0,1 05.3,52.4,46.7,37.0,31.0,30.8,30.6,30.5,29.5,29.3,28.9,28.6, 28.5,28.2,28.2,25.6,21.6,21.6,21.5,13.1,13.0,13.0,10.4.HR-ESI MS (m / z) [M+H] + calcd for C 82 H109 N6S4 1305.7591,found 1305.7582.

[0103] Example 2

[0104] The preparation of the DAD molecule modified with a carbazole derivative having the structure shown in compound 5 is as follows:

[0105]

[0106] 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). Distilled water was added, the organic layer was separated, washed three times with water (30 mL), dried over anhydrous sodium sulfate, concentrated in vacuo, and dried by 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 (400MHz, CDCl3) 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 (101MHz, CDCl3) δ158.2,141.4,140.9,120.9,120.9,120.0,119.4,116.8,115.2,110.8,106.5,92.7,5 4.6,46.7,36.6,30.8,30.8,30.8,30.7,28.9,28.6,28.5,28.2,25.5,25.5,21.6,21.6,13.1,13.1.HR-ESI MS(m / z)[M+H] + calcd for C 29 H43 BrNO 500.2523,found 500.2519.

[0107] 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), bipyralidoborane (485 mg, 1.91 mmol) and potassium acetate (468 mg, 4.77 mmol), and 5 mL of 1,4-dioxane were added to a 50 mL Schlenk tube. The reactants were refluxed and stirred under nitrogen for 12 h. 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 over anhydrous sodium sulfate, filtered, concentrated in vacuo, and dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 20 / 1, v / v). The product was obtained as a colorless oily substance (714 mg, yield 82%, compound 5"). The results of H NMR and C NMR were as follows: Figure 9 and Figure 10 The specific analysis is as follows: 1 H NMR (400MHz, CDCl3) 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 (101MHz, CDCl3) 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] + calcd for C 35 H 55 BNO3 548.4270, found 548.4269.

[0108] Step 3: The solvent 1,4-dioxane (3 mL) and one drop of water were frozen with liquid nitrogen and then heated under vacuum until liquid. 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) were added to a 10 mL Schlenk tube and the atmosphere was purged with nitrogen three times. The solvent was then added to the tube and the atmosphere was purged 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 and 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 dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v). The product was obtained as a dark green solid (63 mg, 60% yield, compound 5). The results of H NMR and C NMR were as follows: Figure 11 and Figure 12 The specific analysis is as follows: 1 H NMR (400MHz, CDCl3) 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 (101MHz, CDCl3) δ158.1,152.3,147.6,144.7,142.0,140.5,129.6,1 27.4,124.3,121.9,120.0,118.7,116.6,115.6,115.2,106.3,105.2,92. 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-ESI MS (m / z) [M+H] + calcdfor C 84 H113 N6O2S4 1365.7802, found 1365.7843.

[0109] Example 3

[0110] The preparation of the DAD molecule modified with a carbazole derivative having the structure shown in compound 7 is as follows:

[0111]

[0112] The first step is to add 9-bromo-7H-benzo[c]carbazole (592 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 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). Distilled water is added, the organic layer is separated, washed three times with water (30 mL), dried over anhydrous sodium sulfate, concentrated in vacuo, and dried by column (200-300 mesh silica gel column, petroleum ether / dichloromethane, 10 / 1, v / v). The obtained product is a colorless oily substance (875 mg, yield 84%, compound 7'). The results of hydrogen nuclear magnetic resonance and carbon nuclear magnetic resonance are as follows: Figure 13 and Figure 14 The specific analysis is as follows: 1 H NMR (400MHz, CDCl3) 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 (101MHz, CDCl3) 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-ESI MS(m / z)[M] +calcd for C 32 H 42 BrN 519.2495, found 519.2498.

[0113] 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), pinacol diboron (485 mg, 1.91 mmol) and potassium acetate (468 mg, 4.77 mmol), and 5 mL of 1,4-dioxane were added to a 50 mL Schlenk tube. The reactants were refluxed and stirred under nitrogen for 12 h. 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 over anhydrous sodium sulfate, filtered, concentrated in vacuo, and dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 20 / 1, v / v). The product was obtained as a colorless oily substance (695 mg, yield 77%, compound 7"). The results of H NMR and C NMR were as follows: Figure 15 and Figure 16 The specific analysis is as follows: 1 H NMR (400MHz, CDCl3) 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 (101MHz, CDCl3) 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-ESI MS(m / z)[M+H] + calcd for C 38 H 55 BNO2 568.4320, found 568.4319.

[0114] Step 3: The solvent 1,4-dioxane (3 mL) and one drop of water were frozen with liquid nitrogen and then heated under vacuum until liquid. 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) were added to a 10 mL Schlenk tube and the atmosphere was purged with nitrogen three times. The solvent was then added to the tube and the atmosphere was purged 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 and 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 dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v). The product was obtained as a dark green solid (75.8 mg, 70% yield, compound 7). The results of H NMR and C NMR were as follows: Figure 17 and Figure 18 The specific analysis is as follows: 1 H NMR (400MHz, CDCl3) 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=9.0,2H),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). 13C NMR (101MHz, CDCl3) δ153.5,148.6,145.9,140.3,139.4,130.3,130.0,1 29.4,129.1,128.7,127.5,127.1,125.6,123.4,123.3,123.1,122.4,118 .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-ESI MS (m / z) [M+H] + calcd for C 90 H 113 N6S4 1405.7904, found 1405.7920.

[0115] Example 4

[0116] The preparation of the alkylfluorene-modified DAD molecule TBTF is as follows:

[0117]

[0118] The solvent, 1,4-dioxane (3 mL), and one drop of water were chilled with liquid nitrogen and then heated under vacuum until liquid. 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), 2-(9,9-dioctyl-9H-fluoren-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 the atmosphere was purged with nitrogen three times. The solvent was then added to the tube and the atmosphere was purged 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 and 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 dried by column chromatography (200-300 mesh silica gel column, dichloromethane / methanol, 100 / 1, v / v). 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: Figure 19 and Figure 20 The specific analysis is as follows: 1H NMR(400MHz, CDCl3).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 (101MHz, CDCl3) 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 ,119.2,119.0,118.7,115.2,54.2,39.5,30.8,30.5,29.5,29.3,29.0,28.2,28.2,22.8,21.6,21.5,13.0,13.0.HR-ESI MS(m / z)[M+H] + calcd for C 84 H 110 N4S41303.7686, found 1303.7692.

[0119] Example 5

[0120] Preparation of nanoparticles

[0121] Mix the aforementioned carbazole and its derivative-modified small molecules (1 mg / mL, 300 μL) and DSPE-PEG2000 (2 mg / mL, 300 μL) in anhydrous THF. Pour the mixture into 10 mL of ultrapure water under ultrasonication and sonicate for another 2 minutes. Concentrate the solution under nitrogen, filter it through a 0.22 μm PES filter, and store it at 4°C until use.

[0122] Folic acid (FA)-functionalized nanoparticles (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 and poured into 10 mL of ultrapure water under ultrasonication for 2 minutes. The solution was concentrated under nitrogen, filtered through a 0.22 μm PES filter, and stored at 4°C until use.

[0123] 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). Figure 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).

[0124] Example 6

[0125] Cell culture and toxicity analysis

[0126] All cell lines were provided by the 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. Culture conditions were 5% CO₂ and 37°C. When cells reached 90% confluence, they were trypsinized and used for subsequent experiments.

[0127] The CCK8 assay was used to evaluate the effect of nanoparticles on the metabolic activity of MCF-7 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). Nanoparticles were not added to the control group 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:

[0128] Viability (%) = average absorbance of the experimental group / average absorbance of the control group (1-1).

[0129] like Figure 22 、 Figure 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.

[0130] Example 7

[0131] Molar extinction coefficient calculation

[0132] According to the Lambert-Beer law, the absorbance and molar concentration of the solution were linearly fitted to calculate the molar extinction coefficient as follows:

[0133] A=εcl(1-2);

[0134] In formula (1-2), A is the absorbance at the wavelength of maximum absorption or 808 nm, ε is the molar extinction coefficient related to the intrinsic properties of the compound, l is the absorption thickness of the optical path, and c is the solution concentration. 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. The absorbance is measured using solutions of varying concentrations.

[0135] The molar extinction coefficients of all small molecules in tetrahydrofuran and their nanoparticles prepared from these small molecules in water were then evaluated. It can be clearly seen that the introduction of carbazole increases the molar extinction coefficient of the DAD molecule (see Table 1). The molar extinction coefficients (ε1) at the peak wavelengths of TBTC-1 and TBTC-2 are both higher than those of TBTF. Even the molecule TBTC-3, which has a higher degree of conjugation, has a coefficient similar to that of TBTF. After being encapsulated by nanoparticles, the molar extinction coefficients of all molecules inevitably decrease, but with the exception of 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.

[0136] Table 1 Optical properties of small molecules and nanoparticles

[0137]

[0138] Note: In Table 1, ε1 is the molar extinction coefficient at the peak wavelength of the absorption spectrum; ε2 is the molar extinction coefficient at a wavelength of 808 nm; QY1 and QY2 are the quantum yields at the fluorescence wavelength ranges of 850-1500 nm and 1000-1500 nm, respectively.

[0139] Example 8

[0140] Quantum yield calculation

[0141] In this example, we used a relative strategy to measure quantum yield (QY). The standard dye IR-26 was used as a reference to measure QY. The calculation formula is

[0142]

[0143] 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 dichloroethane), 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 (1000-1500 nm) and the absorbance at 808 nm, η X and η ST is the refractive index of each solvent (water: 1.333, tetrahydrofuran: 1.465, dichloroethane: 1.4167).

[0144] The quantum yield of the molecules was calculated using IR26 (0.5% in dichloroethane) as a reference. As shown in Table 1, while 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, demonstrating that the degree of fluorescence quenching in TBTC-1 nanoparticles is lower than that in TBTF nanoparticles, and that the introduction of the carbazole group offers significant advantages over the classic fluorene structure. The QY of the small molecules TBTC-2 and TBTC-3 is lower due to their longer conjugated structures, but the QY of TBTC-3 nanoparticles in water is acceptable because the degree of fluorescence quenching in the aggregated state of TBTC-3 is the lowest among these nanoparticles, and the red shift of the emission spectrum results in a relatively high QY in the range beyond 1000 nm.

[0145] Example 9

[0146] Brightness calculation

[0147] The overall brightness is determined by the extinction coefficient and 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, the QE in this discussion is obtained by using ε2×QY2 (Table 1). Among the four nanoparticles, TBTC-3 nanoparticles have the highest brightness (in Figure 24TBTC-3 has the largest area) and may be the most promising material for in vivo NIR-II imaging.

[0148] Example 10

[0149] Vascular imaging

[0150] Vascular imaging was performed using BALB / c nude mice. 50 μL of various nanoparticle aqueous solutions (200 μg / mL) were injected via the tail vein and immediately placed in a small animal in vivo imaging system for image acquisition. All images were acquired under 808 nm excitation and different filter combinations. The camera used in the small animal in vivo imaging system was an InGaAs detector. The imaging system was a Van Gogh IGS1000 near-infrared second-zone imaging system, and the excitation light source was an 808 nm wavelength fiber-coupled laser with a laser output power density of 0.2 W cm -2 , flux = 40 mW cm -2 .

[0151] Vascular imaging of mice was performed to confirm the in vivo NIR-II imaging performance of these nanoparticles. After intravenous injection into nude mice, the hind limb blood vessels were observed under the small animal NIR-II imaging system. Figure 25 As shown in Figure 1, 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. Figure 26 As shown, TBTC-2 and TBTC-3 nanoparticles exhibit strong NIR-II fluorescence emission above 1300 nm due to a red-shifted spectrum, and have a higher signal-to-noise ratio (SBR), demonstrating advantages for in vivo imaging at longer wavelengths. In particular, TBTC-3 nanoparticles, which have the highest brightness, exhibit the best imaging of hindlimb vasculature when their SBR is greater than 2.

[0152] Example 11

[0153] Targeted tumor and metastasis imaging

[0154] In the experiment of establishing tumor-bearing mouse model, female BLAB / c mice were used, and 4T1 cells were eliminated and prepared into cell suspension with a concentration of 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 were selected one week after the injection of cancer cells. 50μL of folic acid-functionalized TBTC-3 nanoparticle aqueous solution (200μg / mL) was injected through the tail vein, and images were collected at the corresponding time points. The camera used for the small animal in vivo imaging instrument is an InGaAs detector. The imaging system is a VanGogh IGS1000 near-infrared second-zone imaging system, the excitation light source is an 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.

[0155] Based on the excellent NIR-II fluorescence performance of TBTC-3 nanoparticles in vascular imaging, their 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. Figure 27 As shown in A, the signal can be clearly detected in the tumor 2 hours after injection, and the SBR reaches its maximum value 12 hours after injection. At the same time, the mice were dissected to study the distribution of nanoparticles. Figure 28 As shown in Figure 2, nanoparticles are mainly distributed in the liver, spleen and tumor, and no signal is found in the heart, kidney and lung, suggesting that they are eliminated through the hepatobiliary metabolic pathway. Figure 29 As shown in the figure, in the absence of modified FA targeting units, TBTC-3 nanoparticles were poorly enriched in mouse breast tumors, indicating the importance of FA in targeted breast cancer imaging. After 24 hours of intravenous injection, the NIR-II fluorescence intensity in mice decreased. The NIR-II signal was unevenly distributed within the tumor, and the signal was clearer when using an 1100lp filter than when using a 1000lp filter ( Figure 27 B). Draw lines to mark the signal intensities read from these two images ( Figure 27 C) This indicates that acquiring signals beyond 1100 nm allows for more accurate understanding of details, prompting us to further image metastases within this fluorescence range.

[0156] 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 intravenously injected into mice, and then the mice were imaged under the NIR-II imaging system. After 8 hours, NIR-II signals were observed in some parts of the body (such as Figure 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 visualize their distribution. Figure 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 area are shown in Figure 2. Figure 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, traditional surgical methods are difficult to detect. However, through NIR-II imaging of bright TBTC-3 nanoparticles, these metastases can be clearly and accurately observed, demonstrating the advantages of high-brightness materials in the NIR-II window.

[0157] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended 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 (II): in: R1 and R2 are independently selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy.

2. 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 (III): in: R1 is selected from: H, halogen, C1-C6 alkyl, C1-C6 alkoxy; R4 is selected from the group consisting of: H, C1-C6 alkyl, C1-C6 alkoxy.

3. The DAD molecule modified with a carbazole derivative according to claim 2, characterized in that: R4 is selected from: H.

4. The DAD molecule modified with a carbazole derivative according to claim 1 or 2, characterized in that The DAD molecule modified with the carbazole derivative is selected from the following compounds:

5. Use of the DAD molecule modified with the carbazole derivative according to any one of claims 1 to 4 in the preparation of functional nanoparticles.

6. 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 4 in a solvent, adding DSPE-PEG2000 and mixing, and adding the mixture into ultrapure water for ultrasonic dispersion; Step 2: removing the solvent from the system after ultrasonic dispersion and separating the solid therein to obtain the functional nanoparticles.

7. The preparation method according to claim 6, characterized in that In the step 1, the mass ratio of the carbazole derivative-modified DAD molecule to DSPE-PEG2000 is 1:1-10; and / or, the solvent is a polar organic solvent; and / or, in the step 2, a 0.22 μm PES filter is used to separate the solid.

8. The preparation method according to claim 7, characterized in that The polar organic solvent is alkyl ether, lower carboxylic acid ester, alkyl alcohol, or aromatic hydrocarbon containing a benzene ring.

9. Functional nanoparticles obtained by the preparation method according to claim 6, 7 or 8.

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

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