阅读说明：本技术 基于胺基芴骨架的快速及长时间溶酶体或细胞核靶向的近红外染色试剂及其制备方法和应用 (Rapid and long-time lysosome or cell nucleus targeted near-infrared staining reagent based on aminofluorene skeleton, and preparation method and application thereof ) 是由 李坤 刘艳昭 陈善勇 余孝其 于 2021-09-23 设计创作，主要内容包括：本发明公开了一种基于胺基芴骨架的快速及长时间溶酶体或细胞核靶向的近红外染色试剂及其制备方法和应用,本发明以胺基芴骨架作为溶酶体或细胞核染料的基础,通过不同形式的烷基胺的调控设计,得到基于胺基芴骨架的溶酶体或细胞核靶向的近红外染色试剂,该类试剂在快速靶向染色的同时,具有超高的稳定性,有利于长时间监测,同时具有较好的生物相容性,不会对活细胞的生理活动产生明显的干扰。由于该染色试剂具有超大斯托克斯位移的特性,在进行生物成像时,基本不会受到激发光所造成的成像干扰,使得该类染料具有高信噪比成像的优势。本发明的制备方法收率高、反应条件温和,制得的染色试剂稳定性好、发射波长较长、斯托克斯位移大、靶向性高。(The invention discloses a rapid and long-time lysosome or cell nucleus targeted near-infrared staining reagent based on an aminofluorene skeleton, and a preparation method and application thereof. Because the staining reagent has the characteristic of ultra-large Stokes shift, the staining reagent can not be basically interfered by imaging caused by exciting light when in biological imaging, so that the staining reagent has the advantage of high signal-to-noise ratio imaging. The preparation method disclosed by the invention is high in yield and mild in reaction conditions, and the prepared dyeing reagent is good in stability, long in emission wavelength, large in Stokes shift and high in targeting property.)

1. A fast and long-time lysosome or cell nucleus targeted near-infrared staining reagent based on an aminofluorene skeleton is characterized in that the structure is shown as formula I:

in the formula I:

R₁is a C1-C10 alkyl chain or an aromatic group;

R₂is composed ofWherein R is a C1-C5 alkyl chain; n is 0, 1,2 or 3.

2. The aminofluorene backbone-based rapid and long-term lysosome or nucleus-targeted near-infrared staining reagent of claim 1, wherein R is₁Is a C3 alkyl chain.

3. The aminofluorene backbone-based rapid and long-term lysosome or nucleus-targeted near-infrared staining reagent according to claim 1, wherein R is a C2 alkyl chain; and n is 1 or 2.

4. The method for preparing a fast and long-term lysosome or nucleus-targeted near-infrared staining reagent based on an aminofluorene skeleton as described in any one of claims 1 to 3, comprising the steps of:

dissolving 3, 6-dibromofluorenone and alkylamine in a first organic solvent, adding a catalyst, a ligand and alkali under the protection of inert gas after deoxygenation, and heating and stirring to obtain a first intermediate;

step (2) adding the first intermediate obtained in step (1) into a reaction vessel containing a second organic solvent, stirring, adding oxalyl chloride, concentrating, adding an organic base and R₁Stirring the substituted organic amine in a second organic solvent to prepare an aminofluorene skeleton-based fast and long-time lysosome or cell nucleus targeted near-infrared dyeing reagent;

or adding the first intermediate obtained in the step (1) into a second organic solvent containing organic base, stirring, adding trifluoromethanesulfonic anhydride, and then adding R₁Stirring substituted organic amine to prepare a rapid and long-time lysosome or cell nucleus targeted near-infrared dyeing reagent based on an aminofluorene skeleton;

wherein R is₁Is a C1-C10 alkyl chain or an aromatic group;

the alkylamine has the following structural formula:

wherein R is a C1-C5 alkyl chain; n is 0, 1,2 or 3.

5. The method for preparing the fast and long-time lysosome or cell nucleus targeting near-infrared staining reagent based on the aminofluorene skeleton as claimed in claim 4, wherein the molar ratio of the 3, 6-dibromofluorenone, alkylamine, catalyst, ligand and alkali in the step (1) is 1 (2.2-3.0): 0.05-0.1): 0.08-0.2): 3.0-7.0; the first intermediate, oxalyl chloride, organic base and R in the step (2)₁The molar ratio of the substituted organic amine is 1 (10.0-100.0): 20.0-50.0): 5.0-20.0; the first intermediate, the organic base, trifluoromethanesulfonic anhydride and R in step (2)₁The molar ratio of the substituted organic amine is 1 (8.0-30.0): (5.0-10.0): 5.0-20.0).

6. The method for preparing a rapid and long-term lysosome or nucleus-targeting near-infrared staining reagent based on an aminofluorene skeleton according to claim 4 or 5, wherein the first organic solvent in the step (1) is at least one of acetonitrile, tetrahydrofuran, dichloromethane, chloroform, dimethyl sulfoxide, o-dichlorobenzene, chlorobenzene, toluene, xylene, mesitylene, 1, 4-dioxane, 1, 2-dichloroethane, N-dimethylformamide and N, N-dimethylacetamide; the catalyst in the step (1) comprises one or two of bis (dibenzylidene acetone) palladium and tris (dibenzylidene acetone) dipalladium; the ligand in the step (1) comprises one or two combinations of tri-tert-butylphosphine and tri-n-butylphosphine; the alkali in the step (1) comprises one or two of potassium tert-butoxide and sodium tert-butoxide.

7. The method for preparing a rapid and long-term lysosome or nucleus-targeting near-infrared staining reagent based on an aminofluorene skeleton according to claim 4 or 5, wherein the second organic solvent in the step (2) comprises at least one of dichloromethane, acetonitrile and tetrahydrofuran; the organic base in the step (2) comprises one or two of triethylamine and pyridine.

8. The method for preparing the aminofluorene skeleton-based rapid and long-time lysosome or cell nucleus targeted near-infrared staining reagent according to claim 4, wherein the heating temperature in the step (1) is 100-120 ℃; the stirring temperature in the step (2) is 0-25 ℃.

9. Use of the aminofluorene backbone based fast and long-term lysosome or nucleus targeted near-infrared staining reagent of any one of claims 1-3 for fluorescence imaging within lysosomes or nuclei of organisms.

10. A near-infrared fluorescent contrast agent comprising the aminofluorene skeleton-based fast and long-term lysosome or nucleus-targeting near-infrared staining reagent of any one of claims 1 to 3.

Technical Field

The invention relates to the technical field of lysosome and cell nucleus targeted staining, in particular to a near-infrared staining reagent for quickly and long-time lysosome or cell nucleus targeting based on an aminofluorene skeleton, and a preparation method and application thereof.

Background

Lysosomes are organelles which decompose biological macromolecules such as proteins, nucleic acids, polysaccharides and the like, contain various hydrolases and are of a 0.025-0.8 micron bubble structure. Lysosomes function in cells by breaking down materials that enter the cell from the outside, and also digesting the local cytoplasm or organelles of the cell itself. The acidic microenvironment (pH 4.5-5.5) in the lysosome can ensure the activity of the hydrolase, so that the process of intracellular digestion and degradation can be smoothly carried out. Lysosomes are also "end-points" of the endocytic process and are associated to some extent with three pathways of cell death, Apoptosis (Apoptosis), Type II Programmed cell death (Type II Programmed cell death) and Necrosis (Necrosis). Therefore, the development of the lysosome targeted fluorescent dye with high selectivity, high sensitivity and high stability for accurately imaging lysosomes in living cells in real time has a very far-reaching significance for exploring and solving the basic biomedical problems related to the lysosomes.

The nucleus is the largest and most important subcellular organelle in eukaryotic cells, is the activity center of cytogenetics and metabolism, and plays an irreplaceable role in the processes of metabolism, growth, differentiation and the like of cells. Abnormalities in the nucleus are also closely related to many biological processes, such as apoptosis, mitosis, and the like. The morphology of the nucleus during apoptosis is obviously distorted, shrunk and enlarged. In addition, the nuclear membrane in mitosis is broken, and DNA self-replication occurs. Therefore, the development of the cell nucleus targeting fluorescent dye with high selectivity, high sensitivity and high stability for accurately imaging the cell nucleus in the living cell in real time has important significance for exploring and solving basic problems of biomedicine and the like related to the cell nucleus.

The conventional commercially available lysosome staining dye is a fluorescent dye based on a BODIPY structure, the fluorescent dye has poor light stability, meanwhile, reductive biological thiols such as glutathione in living cells are easy to interfere, the Stokes shift of the dye is too small, the imaging signal-to-noise ratio is low, the imaging time is long, and the like, and the further application of the dye is limited due to the defects. Therefore, the development of the lysosome targeted fluorescent dye with large Stokes shift, excellent light stability and high dyeing speed is of great significance. The existing commercially available nuclear staining dye generally has the defects of high price, poor light stability of fluorescent dye, short fluorescence emission wavelength, low sensitivity and the like. Therefore, the development of the cell nucleus targeting fluorescent dye with simple synthesis method, excellent light stability, good targeting property and high signal-to-noise ratio is of great significance.

Disclosure of Invention

Aiming at the defects, the invention aims to provide a rapid and long-time lysosome or cell nucleus targeted near-infrared staining reagent based on an aminofluorene skeleton, and a preparation method and application thereof, which can effectively solve the problems of complex operation process, high cost, low imaging result accuracy, long time consumption and the like of the conventional lysosome and cell nucleus targeted dyes caused by complex synthesis, short emission wavelength, small Stokes shift, long imaging time and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a fast and long-time lysosome or cell nucleus targeted near-infrared staining reagent based on an aminofluorene skeleton, which has a structure shown in a formula I:

in formula I:

R₁is a C1-C10 alkyl chain or an aromatic group;

R₂is composed ofWherein R is a C1-C5 alkyl chain; n is 0, 1,2 or 3.

Further, in the preferred embodiment of the present invention:

R₁is a C3 alkyl chain;

R₂is composed ofWherein R is a C2 alkyl chain; n is 1 or 2.

The invention also provides a preparation method of the aminofluorene skeleton-based rapid and long-time lysosome or cell nucleus targeted near-infrared staining reagent, which comprises the following steps:

dissolving 3, 6-dibromofluorenone and alkylamine in a first organic solvent, adding a catalyst, a ligand and alkali under the protection of inert gas after deoxygenation, and heating and stirring to obtain a first intermediate;

step (2) adding the first intermediate obtained in step (1) into a reaction vessel containing a second organic solvent, stirring, adding oxalyl chloride, concentrating, adding an organic base and R₁Stirring the substituted organic amine in a second organic solvent to prepare an aminofluorene skeleton-based fast and long-time lysosome or cell nucleus targeted near-infrared dyeing reagent;

or adding the first intermediate obtained in the step (1) into a second organic solvent containing organic base, stirring, adding trifluoromethanesulfonic anhydride, and then adding R₁Stirring substituted organic amine to prepare a rapid and long-time lysosome or cell nucleus targeted near-infrared dyeing reagent based on an aminofluorene skeleton;

wherein R is₁Is a C1-C10 alkyl chain or an aromatic group;

the alkylamine has the following structural formula:

wherein R is a C1-C5 alkyl chain; n is 0, 1,2 or 3.

Further, the molar ratio of the 3, 6-dibromofluorenone, the alkylamine, the catalyst, the ligand and the alkali in the step (1) is 1 (2.2-3.0): (0.05-0.1): 0.08-0.2): 3.0-7.0; preferably 1:2.2:0.05:0.08: 6.6.

Further, in the step (2), the first intermediate, oxalyl chloride, an organic base and R₁The molar ratio of the substituted organic amine is 1 (10.0-100.0): 20.0-50.0): 5.0-20.0; preferably 1:30.0:20.0: 10.0.

Further, in the step (2), the first intermediate, the organic base, trifluoromethanesulfonic anhydride and R₁The molar ratio of the substituted organic amine is 1 (8.0-30.0): 5.0-10.0): 5.0-20.0; preferably 1:8.0:5.0: 10.0.

Further, in the step (1), the first organic solvent is at least one of acetonitrile, tetrahydrofuran, dichloromethane, trichloromethane, dimethyl sulfoxide, o-dichlorobenzene, chlorobenzene, toluene, xylene, mesitylene, 1, 4-dioxane, 1, 2-dichloroethane, N-dimethylformamide and N, N-dimethylacetamide, and is preferably toluene; the inert gas in the step (1) comprises one or the combination of argon and nitrogen; the catalyst in the step (1) comprises one or two combinations of bis (dibenzylidene acetone) palladium and tris (dibenzylidene acetone) dipalladium; in the step (1), the ligand comprises one or two combinations of tri-tert-butylphosphine and tri-n-butylphosphine; the alkali in the step (1) comprises one or the combination of two of potassium tert-butoxide and sodium tert-butoxide.

Further, the second organic solvent in the step (2) includes at least one of dichloromethane, acetonitrile and tetrahydrofuran; the organic base in the step (2) comprises one or two of triethylamine and pyridine.

Further, the heating temperature in the step (1) is 100-120 ℃, and the stirring temperature in the step (2) is 0-25 ℃.

The invention also provides application of the aminofluorene skeleton-based rapid and long-time lysosome or cell nucleus targeted near-infrared staining reagent in organism lysosome or cell nucleus fluorescence imaging.

A near-infrared fluorescent contrast agent comprises the near-infrared staining reagent for quick and long-time lysosome or nucleus targeting based on the aminofluorene skeleton.

In summary, the invention has the following advantages:

1. the invention provides a fast and long-time lysosome or nucleus targeted near-infrared staining reagent based on an aminofluorene skeleton.

2. The near-infrared dyeing reagent prepared by the invention has longer fluorescence emission (more than 700nm) and larger Stokes shift (more than 140nm), and can effectively avoid the interference of background light; the staining reagent disclosed by the invention has the characteristics of ultra-fast staining and high-stability imaging on the staining of lysosomes, and can be used for monitoring cells for a long time; the staining of the cell nucleus has higher definition and higher stability, and the form of the cell nucleus can be tracked and researched; the problems of complex operation process, high cost, low imaging result accuracy, long time consumption and the like caused by complex synthesis, short emission wavelength, small Stokes displacement, long imaging time and the like of the conventional lysosome and cell nucleus targeting dye are solved.

Drawings

FIG. 1 is a synthetic scheme of the preparation process of the present invention.

FIG. 2 is a hydrogen spectrum of the staining reagent of example 1.

FIG. 3 is a carbon spectrum of the staining reagent of example 1.

FIG. 4 is a hydrogen spectrum of the staining reagent of example 2.

FIG. 5 is a carbon spectrum of the staining reagent of example 2.

FIG. 6 is a hydrogen spectrum of the staining reagent of example 3.

FIG. 7 is a carbon spectrum of the staining reagent of example 3.

FIG. 8 is a UV absorption spectrum of the staining reagent of example 1 in a PBS solution.

FIG. 9 is a UV absorption spectrum of the staining reagent of example 2 in PBS solution.

FIG. 10 is a graph showing the UV absorption spectrum of the staining reagent of example 3 in a PBS solution.

FIG. 11 is a fluorescence emission spectrum of the staining reagent of example 1 in a PBS solution.

FIG. 12 shows fluorescence emission spectra of the staining reagent of example 2 in PBS solution.

FIG. 13 shows fluorescence emission spectra of the staining reagent of example 3 in PBS solution.

FIG. 14 shows CCK-8 cytotoxicity assays of staining reagents of examples 1,2, and 3.

FIG. 15 shows laser confocal lysosomal staining experiments of the staining reagents of examples 1,2, and 3 in HepG2 cells.

FIG. 16 shows the nuclear staining laser confocal experiments of the staining reagents of examples 2 and 3 in HepG2 cells.

FIG. 17 is a photostable laser confocal experiment of lysosomal staining in HepG2 cells with the staining reagents of examples 1,2, and 3.

FIG. 18 is a photostable laser confocal experiment of nuclear staining in HepG2 cells with the staining reagents of examples 2 and 3.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Thus, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

In the examples of the present invention, 3, 6-dibromofluorenone, various solvents, catalysts, ligands, and bases were purchased from Aladdin technologies, Inc., cell lines were purchased from ATCC (American Type Culture Collection), 10% Fetal Bovine Serum (FBS) was purchased from Hyclone, and DMEM medium was purchased from Gibco, USA.

The synthetic route of the embodiment of the invention is shown in figure 1, and the process comprises the following steps:

(1) dissolving 3, 6-dibromofluorenone and alkylamine in a first organic solvent, deoxidizing, protecting with inert gas, adding a catalyst, a ligand and strong base, heating and stirring to obtain a first intermediate;

(2) adding the first intermediate into a second organic solvent, stirring, adding oxalyl chloride, concentrating, adding into a solution containing organic base and R₁Stirring the substituted organic amine in a second organic solvent to prepare an aminofluorene skeleton-based fast and long-time lysosome or cell nucleus targeted near-infrared staining reagent; or adding the first intermediate into a second organic solvent containing an organic base, stirring, adding trifluoromethanesulfonic anhydride, and subsequently adding R₁The substituted organic amine is stirred to prepare the fast and long-time lysosome or cell nucleus targeted near-infrared dyeing reagent based on the aminofluorene skeleton.

The present invention will be further described with reference to the following examples.

Example 1:

the preparation method of the fast and long-time lysosome targeted near-infrared staining reagent 1 with aminofluorene as the framework comprises the following steps:

(1) synthesizing a first intermediate, namely 3, 6-bis (diethylamino) -9H-fluoren-9-one.

The synthetic route is as follows:

to a 250mL two-necked flask was added 80mL of toluene, after deoxygenation, palladium dibenzylideneacetone (86.25mg, 0.15mmol) and tri-tert-butylphosphine (486. mu.L, 0.24mmol, 10% w/v in toluene) were added under argon, stirred at room temperature for 10 minutes, then 3, 6-dibromofluorenone (1.024g, 3.0mmol), diethylamine (483mg, 6.6mmol) and sodium tert-butoxide (1.9g, 19.8mmol) were added, and heated to 110 ℃ for reflux for 18 hours. It was then cooled to room temperature, filtered through celite, washed three times with ethyl acetate and then with dichloromethane until the wash was complete. The organic phases were combined, concentrated and purified by 200-300 mesh silica gel column chromatography. Elution with a petroleum ether/ethyl acetate (20:1) gradient gave the first intermediate as an orange solid in 67% yield.

¹H NMR(400MHz,Chloroform-d)δ7.47(d,J＝8.4Hz,2H),6.72(d,J＝2.3Hz,2H),6.42(dd,J＝8.5,2.3Hz,2H),3.47(q,J＝7.1Hz,8H),1.24(t,J＝7.1Hz,12H)；¹³C NMR(101MHz,Chloroform-d)δ191.2,152.0,146.2,125.4,123.6,109.6,102.3,44.7,12.8.

(2) Synthesizing a fast and long-time lysosome targeted staining reagent based on an aminofluorene skeleton, namely N- (6- (diethylamino) -9- (propylamino) -3H-fluoren-3-ylidene) -N-ethylammonium.

The synthetic route is as follows:

compound 2(64.5mg, 0.2mmol) was added to dichloromethane (10mL), an excess of oxalyl chloride (0.5mL) was slowly added dropwise under ice bath, after 30 minutes of reaction, concentrated under reduced pressure, the concentrate was dissolved in an appropriate amount of dichloromethane, then slowly added to a mixed system of propylamine (118mg, 2.0mmol), triethylamine (404mg, 4.0mmol) and dichloromethane (8mL), stirred at room temperature for 2 hours, then the solvent was distilled off under reduced pressure, and purified by 200-mesh and 300-mesh silica gel column chromatography. Dichloromethane/methanol (30:1) as eluent gave purple solid lysosomal staining reagent 1 in 88% yield.

¹H NMR(400MHz,Chloroform-d)δ10.44–10.14(m,1H),7.94(d,J＝8.8Hz,1H),7.40(d,J＝9.0Hz,1H),6.78(d,J＝2.4Hz,1H),6.67(d,J＝2.3Hz,1H),6.42(dd,J＝8.9,2.4Hz,1H),6.37(dd,J＝9.0,2.5Hz,1H),3.80(q,J＝6.7Hz,2H),3.53(q,J＝7.4Hz,4H),3.48(q,J＝7.3Hz,4H),1.92(h,J＝7.3Hz,2H),1.28(t,J＝7.1Hz,6H),1.24(t,J＝7.1Hz,6H),1.05(t,J＝7.4Hz,3H)；¹³C NMR(101MHz,Chloroform-d)δ166.79,153.34,153.27,148.33,144.27,130.86,128.24,118.58,115.74,110.90,109.78,104.65,103.38,48.37,45.30,45.22,22.31,12.94,11.45.

The hydrogen spectrum and the carbon spectrum of the lysosome targeted staining reagent 1 with aminofluorene as the skeleton prepared in this example are shown in fig. 2 and 3, respectively.

Example 2:

the preparation method of the fast and long-time lysosome or cell nucleus targeted staining reagent 2 taking the aminofluorene as the framework comprises the following steps:

(1) synthesizing a first intermediate, namely 3, 6-dipyrrolidine-9H-fluorene-9-ketone.

The synthetic route is as follows:

to a 250mL two-necked flask was added 80mL of toluene, after deoxygenation, palladium dibenzylideneacetone (86.25mg, 0.15mmol) and tri-tert-butylphosphine (486. mu.L, 0.24mmol, 10% w/v in toluene) were added under argon, stirred at room temperature for 10 minutes, then 3, 6-dibromofluorenone (1.024g, 3.0mmol), tetrahydropyrrole (470mg, 6.6mmol) and sodium tert-butoxide (1.9g, 19.8mmol) were added, and heated to 110 ℃ for reflux for 18 hours. It was then cooled to room temperature, filtered through celite, washed three times with ethyl acetate and then with dichloromethane until the wash was complete. The organic phases were combined, concentrated and purified by 200-300 mesh silica gel column chromatography. Elution with a petroleum ether/ethyl acetate (20:1) gradient gave the first intermediate as an orange solid in 65% yield.

¹H NMR(400MHz,Chloroform-d)δ7.46(d,J＝8.2Hz,2H),6.58(d,J＝2.1Hz,2H),6.26(dd,J＝8.3,2.1Hz,2H),3.38–3.41(m,4H),2.09–1.94(m,4H)；¹³C NMR(101MHz,Chloroform-d)δ191.6,151.7,145.9,125.1,123.7,109.9,103.1,47.9,25.4.

(2) Synthesizing a fast and long-time lysosome or cell nucleus targeted staining reagent 2 based on an aminofluorene skeleton.

The synthetic route is as follows:

compound 3(63.7mg, 0.2mmol) and pyridine (126.6mg, 1.6mmol) were added to dichloromethane (10mL), and trifluoromethanesulfonic anhydride (282mg, 1.0mmol) was slowly added dropwise under ice bath and stirring was continued for 30 min. Then propylamine (118mg, 2.0mmol) was added to the system, stirred at room temperature for 6 hours, after monitoring the completion of the reaction by thin layer chromatography, the solvent was distilled off under reduced pressure, and the crude product was purified by 200-mesh 300-mesh silica gel column chromatography and eluted with dichloromethane/methanol (30:1) to give violet solid lysosome or nuclear staining reagent 2 with a yield of 54%.

¹H NMR(400MHz,Chloroform-d)δ10.08(s,1H),7.82(d,J＝8.7Hz,1H),7.30(d,J＝8.8Hz,1H),6.76(d,J＝2.3Hz,1H),6.63(d,J＝2.2Hz,1H),6.23–6.17(m,2H),3.68(d,J＝9.5Hz,2H),3.47–3.55(m,4H),3.44–3.35(m,4H),2.12–2.07(m,4H),2.05–2.00(m,4H),1.89(h,J＝7.4Hz,2H),1.03(t,J＝7.4Hz,3H)；¹³C NMR(101MHz,Chloroform-d)δ166.9,152.7,152.6,147.8,143.8,130.4,127.5,118.6,115.7,111.0,110.2,105.9,104.6,48.3,48.1,25.3,25.3,22.1,11.3.

The hydrogen spectrum and the carbon spectrum of the fast and long-time lysosome or cell nucleus targeted staining reagent 2 with aminofluorene as the skeleton prepared in the embodiment are respectively shown in fig. 4 and fig. 5.

Example 3:

this example is essentially the same as example 2, except that the starting material pyrrolidine was replaced with azetidine to produce the lysosomal or nuclear staining reagent 3, which was synthesized as follows:

purple solid lysosome or nucleus staining reagent 3 was obtained with yields of 94% and 33% in the two-step reaction, respectively.

Compound 4:¹H NMR(400MHz,Chloroform-d)δ7.46(d,J＝8.1Hz,2H),6.42(d,J＝2.0Hz,2H),6.12(dd,J＝8.2,2.1Hz,2H),4.03(t,J＝7.3Hz,8H),2.43(p,J＝7.3Hz,4H)；¹³C NMR(101MHz,Chloroform-d)δ191.5,155.3,145.6,125.1,124.7,108.9,101.9,51.7,16.5.

lysosomal or nuclear staining reagent 3:¹H NMR(400MHz,Chloroform-d)δ10.16(t,J＝4.9Hz,1H),7.81(d,J＝8.5Hz,1H),7.28(d,J＝8.7Hz,1H),6.49(d,J＝2.2Hz,1H),6.36(d,J＝2.1Hz,1H),5.98(dd,J＝6.4,2.2Hz,1H),5.96(dd,J＝6.4,2.2Hz,1H),4.18(t,J＝7.5Hz,4H),4.05(t,J＝7.4Hz,4H),3.75–3.64(m,2H),2.51(p,J＝7.5Hz,2H),2.43(p,J＝7.3Hz,2H),1.89(h,J＝7.4Hz,2H),1.04(t,J＝7.4Hz,3H)；¹³C NMR(101MHz,Chloroform-d)δ167.0,155.2,155.0,147.5,143.4,130.4,127.4,119.1,115.9,109.0,108.0,103.8,102.7,51.3,48.4,22.0,16.2,11.3.

the hydrogen spectrum and the carbon spectrum of the fast and long-time lysosome or cell nucleus targeted staining reagent 3 with aminofluorene as the skeleton prepared in the embodiment are respectively shown in fig. 6 and fig. 7.

Test example 1 ultraviolet absorption Spectroscopy

The aminofluorene skeleton-based near-infrared staining reagents for rapid and long-term lysosome or nuclear targeting prepared in examples 1 to 3 above were each formulated into DMSO stock solutions at a concentration of 10 mM. Mother liquor of the lysosome-targeted staining reagent is diluted into PBS solution with the concentration of 1.25, 2.5, 5.0, 10.0 and 20.0 mu M, the lysosome-or cell nucleus-targeted staining reagents 2 and 3 are respectively diluted into PBS solution with the concentration of 1,2, 4, 6, 8, 10 and 12 mu M, and the ultraviolet absorption values are respectively scanned and absorption curves are drawn. The ultraviolet absorption spectrum of the staining reagent of example 1 is shown in FIG. 8, the ultraviolet absorption spectrum of the staining reagent of example 2 is shown in FIG. 9, and the ultraviolet absorption spectrum of the staining reagent of example 3 is shown in FIG. 10. As shown in the figure, examples 1,2 and 3 each have three absorption peaks with peak values λ around 340nm, 410nm and 560nm, respectively.

Experimental example 2 fluorescence Spectroscopy

The staining reagents prepared in examples 1,2, and 3 were prepared as DMSO stock solutions at a concentration of 10 mM. Then, each solution was diluted to a concentration of 10. mu.M in PBS, and the fluorescence spectrum was measured to obtain a fluorescence emission curve. In the solution of PBS, the maximum emission wavelength of the samples of examples 1,2 and 3 is significantly red-shifted to the near infrared emission region. The fluorescence intensity of the staining reagent of example 1 is shown in FIG. 11, the fluorescence intensity of the staining reagent of example 2 is shown in FIG. 12, and the fluorescence intensity of the staining reagent of example 3 is shown in FIG. 13.

Test example 3 CCK-8 cytotoxicity test

HepG2 cells in logarithmic growth phase were seeded in 96-well plates at approximately 10000 cells per well in DMEM (H) medium containing 10% Fetal Bovine Serum (FBS), 1% double-resistant (penicillin-streptomycin, 1000KU/L) at 37 ℃ and 5% CO₂Incubated under conditions for 24 hours. When the cells are completely attached to the wall, the staining reagents prepared in examples 1,2 and 3 with different concentration gradients are added, each concentration is provided with 3 multiple wells, and a blank control group is arranged at the same time. After the incubation for 24 hours after the addition of the staining reagent, the viability of the cells was measured by using the CCK-8 toxicity kit, and the results are shown in FIG. 14. Examples 1,2, and 3 all showed high cytotoxicity to HepG2 cells at a high concentration of 8 μ M. However, when the concentration was reduced to 4. mu.M, the cell survival rate was around 80%.

Test example 4 laser confocal imaging of lysosome staining of HepG2 cells

HepG2 cells were cultured overnight in 35 mm dishes. After a certain concentration of the compound of examples 1,2 and 3 (1. mu.L of compound stock solution with a concentration of 1mM in 1mL PBS) for a certain time, the dye was imaged under a confocal laser microscope using appropriate excitation and emission filters, i.e., the excitation wavelength and the absorbance range of examples 1,2 and 3 were each lambda_ex＝543nm，λ_em600 and 740 nm. The results are shown in FIG. 15. Because the probe is water soluble, it is expected that the probe will be uniformly dispersed in aqueous solution and the positive charge characteristic of the probe will allow rapid entry into the lysosome. Based on this, we can achieve lysosomal imaging.

Experimental example 5 confocal laser imaging of HepG2 cell nucleus staining

HepG2 cells were cultured overnight in 35 mm dishes. After a certain time of staining with a certain concentration of examples 2 and 3 (4. mu.L of compound stock solution with a concentration of 1mM in 1mL PBS), the dye was imaged under a confocal laser microscope using appropriate excitation and emission filters, i.e., the excitation wavelength and the light absorption range of examples 2 and 3 were both lambda_ex＝543nm，λ_em600 and 740 nm. The results are shown in FIG. 16. Due to the high planarity and rigidity of the probe, it is expected that the probe will bind to DNA, while high concentrations of the probe will escape from the lysosome and into the nucleus. Based on this, we can achieve nuclear imaging.

Test example 6 photostable laser confocal imaging of HepG2 cell lysosome staining

HepG2 cells were cultured overnight in 35 mm dishes. After staining with a certain concentration of examples 1,2 and 3 (1. mu.L of compound stock solution with a concentration of 1mM in 1mL PBS) for a certain time, the stains were imaged under a confocal laser microscope with 100% intensity excitation light and emission filter, wherein the excitation wavelength and the light absorption range of examples 1,2 and 3 are all lambda_ex＝543nm，λ_emThe images were taken every 5 seconds for a total of 50 images at 600 and 740 nm. The results are shown in FIG. 17. The probe has higher light stability, and long-time imaging of lysosome can be realized based on the probe.

Test example 7 light-stable confocal laser imaging of HepG2 cell nucleus staining

HepG2 cells were cultured overnight in 35 mm dishes. After a certain concentration of the compound of examples 2 and 3 was stained for a certain time (4. mu.L of compound stock solution with a concentration of 1mM was added to 1mL of PBS), the dye was imaged under a laser confocal microscope using 100% intensity excitation light and an emission filter, wherein the excitation wavelength and the light absorption range of examples 2 and 3 are both lambda_ex＝543nm，λ_emThe images were taken every 5 seconds for a total of 50 images at 600 and 740 nm. The results are shown in FIG. 18. Due to the high planarity and rigidity of the probe, it is expected that the probe will bind to DNA, while high concentrations of the probe will escape from the lysosome and into the nucleus. Simultaneous probe comparisonHigh photostability, based on which we can achieve long-term imaging of the nuclei.

In conclusion, the invention takes the aminofluorene as the skeleton as the basis of the lysosome or nuclear dye, and obtains the fast and long-time lysosome or nuclear targeted near-infrared dyeing reagent based on the aminofluorene skeleton through the reasonable regulation design of the alkylamine. At low concentration, the reagent can be quickly targeted to lysosomes, and can be used for imaging and monitoring the lysosomes for a long time; at high concentrations, such agents may escape from the lysosome and enter the nucleus, allowing longer imaging monitoring of the nucleus. In addition, the staining reagent has the characteristics of near infrared emission and larger Stokes shift, so that the staining reagent has the performances of low background fluorescence and high imaging signal-to-noise ratio. The preparation method is simple and high in yield, and the prepared dyeing reagent is large in Stokes shift, good in stability and high in targeting property.

The foregoing is illustrative and explanatory of the preferred embodiment of the invention, and it is within the scope of the patent appended hereto that modifications or additions may be made to the described embodiments or substitutions may be made by those skilled in the art without inventive faculty.