CN111671771B

CN111671771B - Graphene base targeting DNA major groove and inhibiting topoisomerase and preparation method and application thereof

Info

Publication number: CN111671771B
Application number: CN202010638282.3A
Authority: CN
Inventors: 潘登余; 耿弼江
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2019-08-29
Filing date: 2020-07-06
Publication date: 2022-07-05
Anticipated expiration: 2040-07-06
Also published as: CN111671771A; CN110917212A; WO2021036654A1

Abstract

The invention discloses a graphene base targeting a DNA major groove and inhibiting topoisomerase, a preparation method and application thereof. The graphene base of the bioactive nano particle has a simple structure, is easy to synthesize, has an accurate targeting function on a nuclear DNA major groove, has high-efficiency inhibition activity on topoisomerase I and topoisomerase II, and particularly can show anticancer activity higher than that of a chemotherapeutic drug under the condition that the graphene base does not contain small molecular drug components and grafted special targeting molecules.

Description

Graphene base targeting DNA major groove and inhibiting topoisomerase and preparation method and application thereof

Technical Field

The invention relates to the field of pharmaceutical chemistry, in particular to graphene base which targets DNA major groove and inhibits topoisomerase, and a preparation method and application thereof.

Background

DNA and topoisomerase (Topo) are important targets for anticancer drugs. Topoisomerase inhibitors which have been widely used clinically and are under development are mainly DNA intercalators which indirectly interfere with the function of topoisomerase I or II mainly by means of DNA base intercalation, resulting in DNA damage and apoptosis. In recent years, in order to overcome the drug resistance limitation of single topoisomerase inhibitors, some dual inhibitors targeting Topo I and Topo II are discovered, such as indolyl quinoline derivative TAS-103, prodigiosin, curcumin and the like. However, the discovered small-molecule dual Topo inhibitors have great toxic and side effects and poor clinical test effects.

The development of novel anti-cancer drugs targeted to the DNA major groove is of particular interest because, in addition to the topoisomerase target binding to the DNA major groove, many other nuclear protein targets of interest, such as polymerases, transcription factors, and DNA repair proteins, can also specifically bind to the DNA major groove. In particular, the DNA major groove targeted drug can compete with a plurality of major groove binding proteins for DNA major groove sites to directly interfere the functions of the DNA major groove targeted drug, so that the multi-target anticancer effect can be realized, the metastasis of malignant tumors can be obviously inhibited, and the multi-drug resistance of the tumors can be overcome. However, small molecule drugs and dyes interact with DNA primarily by way of base insertion or minor groove binding, and only a few dyes have been found to have the property of binding to the major groove of DNA, but they have not been found to have anticancer activity. An anticancer drug with definite DNA major groove targeting characteristics has not been reported or clinically applied so far.

In summary, the DNA-embedded or minor groove-bound small molecule chemotherapeutic drugs have the defects of single action target, difficulty in inhibiting tumor metastasis, easy generation of multidrug resistance, large toxic and side effects, and the like. Therefore, the development of a multi-target anti-cancer drug which targets the DNA major groove, simultaneously inhibits topoisomerase I and topoisomerase II with high efficiency, has good safety, is not easy to generate drug resistance and particularly can obviously inhibit tumor metastasis is urgently needed.

Disclosure of Invention

The invention provides graphene base for targeting DNA major groove and inhibiting topoisomerase and a preparation method and application thereof in order to solve the problems in the prior art.

The invention provides a bioactive nano particle graphene base which is simple in structure and easy to synthesize, wherein the nano particle graphene base not only has a targeting function on nuclear DNA major groove, but also has high-efficiency inhibition activity on topoisomerase I and topoisomerase II, and particularly can show anticancer activity higher than that of chemotherapeutic drugs under the condition that the nano particle graphene base does not contain small molecular drug components and grafted special targeting molecules. In addition, the graphene base also has the activity of reversing tumor multidrug resistance (MDR) and inhibiting tumor metastasis. The graphene base can also be used as a DNA fluorescent probe for labeling nucleic acid and cell nucleus.

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

the invention provides a graphene base for targeting a DNA major groove and inhibiting topoisomerase, which comprises a nano-scale graphene planar structure different from a planar structure of micromolecule alkaloid, wherein the size of the graphene planar structure is 1-10 nm, and the thickness of the graphene planar structure is 0.34-3.4 nm.

Further, the geometrical size of the graphene base is as follows: the average transverse dimension is 3.5 +/-0.5 nm, and the thickness range is 0.34-1.0 nm. Where the average lateral dimension is the TEM measured dimension and the thickness is the AFM measured dimension.

Further, the quasi-molecular weight of the graphene base is 2000-20000.

Further preferably, the quasi-molecular weight of the graphene base is 6000-10000.

Further, besides the graphene planar structure, the graphene base also contains a nitrogen heterocyclic ring cluster structure which is covalently bonded to the edge of the graphene planar structure.

Further preferably, the nitrogen heterocyclic ring cluster structure comprises a pyridine ring, a pyrrole ring, a phenol ring or a combination thereof.

More preferably, the nitrogen heterocyclic ring cluster structure comprises a combination of 10-50 heterocyclic rings.

More preferably, the nitrogen heterocyclic ring cluster structure comprises a combination of 15-30 heterocyclic rings.

More preferably, the ratio of N in the pyridine ring structure, N in the pyrrole ring structure and N in the graphite N ring structure is pyridine N: pyrrole N: graphite N (atomic ratio) ═ 2.0 to 5.0: (0.1-0.8): 1.

further, the content of N in the graphene base is 5-20 at%, and at% refers to atomic percentage.

More preferably, the content of N in the graphene base is 7.8 to 15.6 at%, and at% refers to atomic percentage.

More preferably, the content of N in the graphene base is 10.4 ± 0.5 at%, and at% refers to atomic percentage.

Further, the Zeta potential of the grapheme base is between +33.2 and +72.3eV at physiological pH (pH between 6.5 and 7.4) and/or in a concentration range of 0.01 and 1.0 mg/mL.

Further, the maximum absorption of the aqueous solution of the graphene alkaloid is 430-480 nm, and/or the fluorescence emission is 530-560 nm. The GA fluorescence emission peak red-shifted less than 5nm when the excitation wavelength was shifted from 400nm to 500 nm.

In a second aspect, the present invention provides a method for preparing a graphene base targeting a DNA major groove and inhibiting topoisomerase, comprising the steps of:

(a) one-step reaction: in the presence of a catalyst, in an alcohol solvent, carrying out a one-step reaction on a precursor to form the graphene base;

wherein the precursor is Julolidine (juliodine); the catalyst is organic acid and/or anhydride thereof, and/or a phosphorus-containing compound.

Further, in the step (a), the organic acid catalyst is selected from one or more of acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid and phthalic acid.

Further, in the step (a), the phosphorus-containing compound is selected from one or a combination of several of phosphorus pentoxide, phosphorus oxychloride and phosphorus pentachloride.

Further, in the step (a), the alcohol solvent is selected from one or a combination of several of ethanol, n-propanol, isopropanol, n-butanol and isoamyl alcohol.

Further, in the step (a), the mass-to-volume ratio (mg: ml) of the precursor to the alcohol solvent is (2.0-3.0): 1.

Further preferably, in the step (a), the mass-to-volume ratio (mg: ml) of the precursor to the alcohol solvent is (2.0-2.5): 1.

Further, in the step (a), when the catalyst is a liquid, the volume ratio of the catalyst to the alcohol solvent is 1 (4-40).

Further preferably, in the step (a), when the catalyst is a liquid, the volume ratio of the catalyst to the alcohol solvent is 1 (10-40).

Further, in the step (a), when the catalyst is a solid, the ratio of the mass volume (mg: ml) of the catalyst to the mass volume (mg: ml) of the alcohol solvent is 1: (40-400).

Further preferably, in the step (a), when the catalyst is a solid, the ratio of the mass volume (mg: ml) of the catalyst to the mass volume (mg: ml) of the alcoholic solvent is 1: (100-400).

Further, in the step (a), the reaction temperature is 100-300 ℃, and the reaction time is 0.05-24 h.

Further, the preparation method of the graphene base which targets the DNA major groove and inhibits topoisomerase further comprises the following steps:

(b) and (3) post-treatment: separating and/or purifying the graphene base formed in the one-step reaction.

Further, the post-processing steps are as follows: (i) a post-treatment based on petroleum ether extraction, (ii) a post-treatment based on column chromatography separation, and/or (ii) a post-treatment based on salt precipitation centrifugation.

A third aspect of the invention provides a use of a graphene base as defined in any one of the above for targeting the DNA major groove and inhibiting topoisomerase, (i) for the preparation of an inhibitor for inhibiting topoisomerase; and/or (ii) for the manufacture of a medicament or composition thereof for the treatment and/or prevention of cancer.

Further, the topoisomerase includes two types of topoisomerase I and II.

Further, the pharmaceutical composition comprises the graphene base and a pharmaceutically acceptable carrier or a small molecule drug or an antibody or an immune drug.

Further, the cancer includes: colon cancer, breast cancer, gastric cancer, lung cancer, carcinoma of large intestine, pancreatic cancer, ovarian cancer, prostatic cancer, renal cancer, hepatocarcinoma, brain cancer, melanoma, multiple myeloma, chronic myelogenous leukemia, and malignant lymphoma.

Optionally, the treatment and/or prevention comprises: reversing drug resistance in resistant cells and/or inhibiting metastasis of cancer cells.

In a fourth aspect of the invention there is provided a method of inhibiting topoisomerase I and/or topoisomerase II comprising the steps of: contacting the graphene base with the subject as described above to inhibit topoisomerase I and/or topoisomerase II.

Further, the object includes: a cell. Preferably, the cell comprises: MCF-7 human breast cancer cells, human osteogenic sarcoma MG-63, human pancreatic cancer PANC-1, human liver cancer HepG2, human lung cancer A549, mouse breast cancer 4T1, gastric cancer Hgc-27, human colon cancer HCT-8, malignant melanoma A375, and one or more of human cervical cancer Hela.

In a fifth aspect of the present invention, there is provided a method of treating and/or preventing a disease, comprising the steps of: administering to a subject in need thereof a graphene base as described above.

Further, the disease is selected from: cancer, a disease associated with too high activity of topoisomerase I and/or topoisomerase II, or a combination thereof.

Further, the subject is an animal. Preferably, the subject is a mammal; more preferably, the subject is a human.

The sixth aspect of the invention provides an application of graphene base, in a specific embodiment, the application is an application of graphene base in preparation of a reversal agent for reversing tumor multidrug resistance and/or an application in preparation of an inhibitor for inhibiting cancer cell metastasis, wherein the graphene base can target a DNA major groove and comprises a nano-scale graphene planar structure, and the size of the graphene planar structure is 1-10 nm, and the thickness of the graphene planar structure is 0.34-3.4 nm.

Optionally, the subject to which the reversal agent or inhibitor is administered is an animal or a cell. Further optionally, the subject is a mammal.

Optionally, the tumor multidrug resistance comprises one or more of breast cancer adriamycin resistance, colon cancer paclitaxel resistance and cervical cancer cisplatin resistance.

Further optionally, the subject to which the reversal agent is administered comprises one or more of human breast cancer doxorubicin-resistant cells MCF-7/ADR, human colon cancer paclitaxel-resistant cells HCT-8/PTX, and human cervical cancer cisplatin-resistant cells Hela/DDP.

In a seventh aspect, the invention provides a fluorescent probe for labeling nucleic acids and/or cell nuclei. In one embodiment, the fluorescent probe comprises a graphene base; the graphene base can target a DNA major groove and comprises a nano-scale graphene planar structure, wherein the size of the graphene planar structure is 1-10 nm, and the thickness of the graphene planar structure is 0.34-3.4 nm. Wherein labeling the nucleus comprises nuclear imaging.

Further, the fluorescent probe can be used for labeling isolated DNA or nuclei in living cells.

Optionally, when the fluorescent probe is used for DNA labeling, the wavelength range of the exciting light is 350-500nm, and the wavelength of the emitting light is 530-560 nm; when the fluorescent probe is used for the nuclear marker of living cells, the excitation wavelength is selected from 405nm, 488nm and 543nm, and the corresponding detection wavelengths are respectively 410-500nm, 500-600nm and 550-620 nm.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

By adopting the technical scheme, compared with the prior art, the invention has the following technical effects:

(a) the graphene base is not easy to cause drug resistance of a treatment object; (b) the graphene base can effectively inhibit cancer cell metastasis; (c) the graphene has less toxic and side effects; (d) the graphene base can directly target tumor tissues, and particularly can target nucleic acid or ribozyme; (e) the graphene base can overcome multiple biological barriers in cells; (f) the graphene alkali provided by the invention has a stable structure and is easily dissolved in water; (g) the graphene base is simple to prepare and easy to control; (h) the graphene base can be used as an ultra-stable fluorescent probe.

Drawings

Figure 1 shows a structural model of graphene base GA;

TEM picture of a) GA in fig. 2; b) HRTEM picture of GA; c) AFM pictures of GA.

In fig. 3a) X-ray diffraction pattern of graphene base GA; b) a raman spectrogram of graphene base GA;

figure 4 a) XPS summary of graphene base GA; b) c1s spectrum of graphene base GA; c) an N1s spectrum of graphene alkaloid; d) an O1s spectrum of graphene base GA;

in fig. 5a) Zeta potential of graphene base GA under different pH conditions; b) zeta potential of graphene base GA under different concentrations;

in fig. 6 a) a fluorescence picture, uv-vis absorption spectrum and fluorescence excitation and emission spectrum of graphene base GA ethanol solution; b) ultraviolet visible absorption spectrum and fluorescence excitation and emission spectrum of the graphene alkali GA aqueous solution; c) testing the fluorescence stability of the graphene alkali GA ethanol solution and the graphene alkali aqueous solution under continuous ultraviolet irradiation;

figure 7 a) effect of graphene oxide GA on cell survival of various types of cancer cell lines; b) semi-lethal concentration (IC) of graphene GA on different types of cancer cell lines₅₀)；

FIG. 8 compares the semi-lethal concentration (IC) of graphene GA on Hela cells with the small molecule topoisomerase inhibitors Doxorubicin (DOX), hydroxycamptothecin (CPT-11) and etoposide (VP-16)₅₀)；

Figure 9 shows experimental evidence of graphene base GA binding to the major groove of double stranded DNA: influence of different concentrations of graphene base GA on characteristic circular dichroism peaks generated by binding of major groove binding dye methyl green with ct-DNA;

figure 10 shows the results of an assessment of inhibition of topoisomerase I activity by graphene base GA;

figure 11 shows the results of an assessment of inhibition of topoisomerase II activity by graphene base GA;

figure 12 shows the therapeutic effect of graphene base GA on MCF-7 tumors by intratumoral injection in vivo; wherein, adriamycin DOX is used as a positive control;

FIG. 13 shows the therapeutic effect of graphene base GA on Hela, HepG-2, 4T1 and A549 tumors by intravenous injection in vivo (doxorubicin DOX as a positive control);

figure 14 shows the change in body weight of mice after treatment with graphenic base GA (doxorubicin as a positive control);

figure 15 shows the number of metastases of the tumor in the lung after treatment of 4T1 tumor with graphene base GA by intravenous injection in vivo (doxorubicin DOX as positive control);

fig. 16 shows the plasma concentration-time curve after a single tail vein injection of graphene base GA in mice;

figure 17 shows in vivo imaging of graphene base GA passively targeted to tumors by intravenous injection;

figure 18 shows the distribution of graphene base GA in organs in vivo following administration by in vivo imaging after intravenous injection;

figure 19 shows long-term toxicity assessment of graphene base GA, wherein major organs were taken at different time points for histological analysis after intravenous injection of graphene base GA;

fig. 20 shows long-term toxicity evaluation of graphene base GA, where whole blood was taken at different time points for routine blood analysis and biochemical blood analysis after intravenous injection of graphene base GA;

fig. 21 shows a hemolysis experiment of graphene base GA;

FIG. 22 shows cellular imaging of graphene base GA and doxorubicin DOX on drug-sensitive and drug-resistant cells;

FIG. 23 shows the semi-lethal concentrations of graphene base GA and the commonly used small molecule chemotherapeutic drugs on drug-sensitive cells (MCF-7) and drug-resistant cells (MCF-7/ADR), showing the change in the resistance index of the small molecule chemotherapeutic drugs in the presence or absence of graphene base.

FIG. 24 shows the semi-lethal concentrations of graphene base GA and the commonly used small molecule chemotherapeutic drugs on drug-sensitive cells (HCT-8) and drug-resistant cells (HCT-8/PTX), showing the change in the resistance index of the small molecule chemotherapeutic drugs in the presence or absence of graphene base.

FIG. 25 shows a scratch experiment of the ability of graphene base GA to inhibit cell migration of 4 cancer cells (A375, HepG2, 4T1, PANC-1).

Figure 26 shows a Transwell experiment of the ability of graphene base GA and small molecule chemotherapeutic drugs (doxorubicin DOX and paclitaxel PTX) to inhibit cell migration of 4T1 cells.

Figure 27 shows a Transwell experiment of the ability of graphene base GA and small molecule chemotherapeutic drugs (doxorubicin DOX and paclitaxel PTX) to inhibit cell invasion of 4T1 cells.

Figure 28 shows in vivo imaging of the ability of the graphenes GA and doxorubicin DOX to inhibit lung metastasis of 4T1-Luc cells in vivo.

Fig. 29 shows a gel electrophoresis of graphene base GA and commercial nucleic acid dye-labeled DNA.

Fig. 30 shows targeted nuclear imaging of graphene base GA and the commercial nucleic acid dye SYTO 17.

Fig. 31 shows that when the graphene base GA and the commercial nucleic acid dye SYTO17 were subjected to nuclear imaging, the light excitation time was prolonged, and a change in the fluorescence imaging effect (stability) was observed.

Detailed Description

The present invention, through extensive and intensive studies, has unexpectedly developed a graphene-based anticancer drug GA having a novel structure, which has excellent inhibitory activities of topoisomerase I and II for the first time. In addition, research also shows that the GA medicament provided by the invention has a planar structure of ultrathin nano graphene. The present invention has been completed based on this finding.

As used herein, "graphene alkaloid", "graphene alkaloid drug", "graphene base drug", "graphene base nano drug", "graphene base anti-cancer drug", "graphene quantum dot active drug", and "GA drug" are used interchangeably and refer to planar ultra-thin nano-graphene alkaloid, GA.

As used herein, the nanopharmaceutical or active ingredient of the present invention refers to the graphene base of the first aspect.

Graphene base medicine

The invention provides a non-small molecule type anticancer drug which is targeted to act on nuclear DNA major groove and simultaneously inhibits topoisomerase I and II.

The molecular structure of the graphene alkaloid of the present invention is substantially as shown in fig. 1.

In addition, compared with the traditional micromolecular drugs, the graphene alkali anticancer drug has obviously different structural characteristics, physicochemical characteristics and pharmacological characteristics.

In one embodiment, the graphenic base used as the active ingredient in the present invention has one or more of the following characteristics:

one of the characteristics is as follows: the graphene alkali is a derivative of graphene, can be regarded as an ultra-stable pi conjugated planar macromolecule, is formed by fusing more than dozens of benzene rings and nitrogen heterocycles, and has the average molecular weight equivalent to that of a polypeptide molecule. The medicine can maintain chemical stability and biological activity even in special physiological environment (such as gastric acid, liver, cell lysosome), and will not be biodegraded to lose efficacy.

The second characteristic is that: graphene alkali belongs to an artificially synthesized alkaloid-like active medicine. Different from natural alkaloid drugs, the pharmacophore of graphene base is an alkaline nitrogen heterocyclic cluster which surrounds the perimeter of a graphene planar framework and is tightly fused with a graphene base surface, and mainly comprises a six-membered pyridine ring, a five-membered pyrrole ring and a phenol ring.

Thirdly, the characteristics are as follows: the graphene alkali has adjustable size, so that the drug can be targeted on tumor tissue cell nucleuses without influencing normal tissue cells. The lateral size of the graphene base can be limited within the range of 2-10 nanometers, and the upper limit of the size of the graphene base allows nanoparticles to smoothly pass through nuclear pores (the diameter is 10nm), so that the graphene base targets a DNA double chain acting on tumor cell nucleuses. The lower size limit is set to take into account the significant difference in microvascular structure and permeability between normal and tumor tissues. For normal tissues without pathological changes, the capillaries are complete, endothelial cells are closely arranged, the gaps are as small as 1-2 nanometers, small-molecule medicines are easy to permeate and generate toxic and side effects, and the nano medicines are not easy to permeate and can reduce the toxic and side effects. Solid tumor tissues are different: poor structural integrity of blood vessels, abnormal widening of endothelial cell gaps, and lymphatic return loss, resulting in high permeability and retention (EPR effect) to nano-drugs. By utilizing the EPR effect of the nanoparticles, the passive targeting of the graphene drug to the solid tumor can be realized.

The characteristics are as follows: the graphene base selectively targets a large groove region of nuclear DNA and is a dual inhibitor of topoisomerase I and II. The graphene base is irregular in shape, and the edges of the graphene base are provided with fine edges and corners, so that the graphene base can be selectively inserted into the bottom of a DNA major groove in a targeted manner. The graphene corner tip part contains a plurality of nitrogen heterocycles with positive charges, and generates strong electrostatic interaction with a DNA phosphodiester bond framework with negative charges, and meanwhile, the drug tip contains a hydrogen bond donor and an acceptor, and can generate hydrogen bond interaction with the acceptor or the donor of a base in a DNA major groove. The major groove region of DNA is the binding site of various DNA binding proteins such as topoisomerase I and II and protein transcription factors, and the graphene base plane inserted into the major groove of DNA can block the reconnection of topoisomerase to DNA single strand break points or double strand break points, resulting in irreversible damage to DNA. And the graphene alkaloid inserted into the DNA major groove further hinders the cells from repairing DNA damage, so that the cells are subjected to apoptosis. The unique graphene-DNA-protein nano interface effect forms the pharmacological basis of the graphene base planar drug as a dual topoisomerase I and II inhibitor.

The fifth characteristic is that: the graphene base has the optical characteristics of quantum dots, has extremely stable fluorescence property, and can be applied to DNA labeling and cell nucleus fluorescence imaging.

Preparation method

The second purpose of the invention is to provide a synthetic method of the graphene base.

The method for synthesizing the graphene base is based on an organic phase catalytic molecular fusion method, wherein a nitrogen heterocyclic aromatic compound (Julolidine) is used as a drug precursor, and a graphene base solution product (glucose injection or physiological saline injection thereof) which can be stably stored at room temperature for a long time without agglomeration is finally obtained through one-step solvent thermocatalytic reaction and subsequent separation and purification in an alcohol solvent. Compared with the synthesis of the traditional organic micromolecule chemotherapeutic drug, the synthesis method has the advantages of few synthesis steps (only single-step synthesis), mild and safe reaction (120 ℃), short synthesis time (1h), green and environment-friendly synthesis process (only using nontoxic ethanol and acetic acid), good repeatability, low synthesis cost, high total yield (55%), and the like.

In another preferred embodiment, the alcohol solvent can be replaced by ethanol, n-propanol, isopropanol, n-butanol, or isoamyl alcohol in carrying out the above reaction. The catalyst can be replaced by acetic acid, propionic acid, butyric acid, caprylic acid, adipic acid, oxalic acid, malonic acid, succinic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid, phthalic acid or anhydride, or phosphorus oxychloride, phosphorus pentachloride and phosphorus pentoxide.

In carrying out the above synthesis, the solvothermal reaction is carried out in a reaction vessel (e.g., a teflon reaction vessel), or may be carried out under microwave-assisted conditions, or may be carried out under reflux in a high boiling point solvent at atmospheric pressure. Preferably, a solvothermal synthesis method (performed in a teflon reaction kettle or an industrial reaction kettle) is adopted, and the method is easy to produce on a large scale and has lower cost.

In the process of separating and purifying the product, petroleum ether is used for extracting and removing fat-soluble small molecular impurities. The product separation can also adopt a chromatographic column separation method and a salt sedimentation centrifugal separation method.

In a specific embodiment, the invention provides a preparation method of a graphene base nano-drug, wherein the preparation method comprises the following steps:

a. julolidine (juliodine) is taken as a precursor, dissolved in an alcohol solvent, added with a catalyst and stirred together, and then transferred into a polytetrafluoroethylene high-pressure reaction kettle to be subjected to heat preservation reaction for 1-12 hours under the heating condition of 120-230 ℃;

b. after natural cooling, filtering with a 220nm filter membrane to remove insoluble impurities, and further separating and purifying to remove non-anticancer active organic small molecular impurities.

In another preferred example, in step a, the alcohol solvent can be one of ethanol, n-propanol, isopropanol, n-butanol and isoamyl alcohol. Preferably, ethanol is selected as the solvent.

In another preferred embodiment, in step a, the catalyst may be one of acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid, phthalic acid, organic acid, phosphorus pentoxide, phosphorus oxychloride and phosphorus pentachloride, and preferably, acetic acid is used as the catalyst.

In another preferred example, the concentration of the precursor in the alcohol solvent is 2.0-2.5 mg/mL, and the volume ratio of the solvent to the catalyst is 4-40.

In another preferred embodiment, in the step b, the purification is performed by an extraction purification method, which comprises the steps of: extracting with petroleum ether, and removing residual small molecular impurities for multiple times.

In another preferred embodiment, in step b, the separation is performed by a chromatographic column separation method, comprising the steps of: firstly dispersing graphene alkali in a trichloromethane solution, then adding the solution into a neutral aluminum oxide chromatographic column, using a mixed solution of trichloromethane, cyclohexane and ethanol as an eluent, and collecting the separated graphene alkali solution according to the characteristic that the graphene alkaloid medicament emits yellow fluorescence under an ultraviolet lamp.

In another preferred embodiment, in step b, the separation is performed by salt settling centrifugation comprising the steps of: removing the solvent in the graphene alkali ethanol solution by a rotary evaporation method, dispersing in 20mL of water, adding 0.2g of nitrate for dissolving, standing the solution for 10 minutes, separating out graphene alkali from the solution, and separating the separated graphene alkaloid by centrifugation.

In a specific embodiment, the invention also provides another preparation method of the graphene base nano-drug, which comprises the following steps: adding 0.1g juliodine (juliodine) into 40mL of high boiling point solvent such as isoamyl alcohol, n-octanol or dodecanol, and then adding 1-3 mL of acetic acid, or 0.02-0.1 g of acetic anhydride, or 0.02-0.1 g of phosphorus pentoxide (or phosphorus oxychloride, phosphorus pentachloride and the like) into the solution. And transferring the mixture into a 100mL three-neck flask after the mixture is completely dissolved, heating the mixture in an oil bath kettle in a reflux manner at the temperature of 130-170 ℃, and preserving the heat for 40-120 min. After the reaction is finished, separating and purifying by a nitrate selective sedimentation method.

In a specific embodiment, the invention also provides another preparation method of the graphene base nano-drug, which comprises the following steps: julolidine (juliodine) (0.1g) is dissolved in 10mL of absolute ethanol, and 0.1-1 mL of acetic acid is added and stirred for 10 min. Then transferring the solution into a 35mL reaction tube of a microwave reactor, and reacting for 5-60 min under the microwave heating condition of 120-200 ℃. After the reaction is finished, the graphene alkali is selectively settled by nitrate, and then the graphene alkali is separated and purified.

Application of graphene base

The third purpose of the invention is to provide the anticancer application of the graphene alkaloid.

GA or an anticancer drug containing it combines the unique biological activity of graphene alkaloids with the unique pharmacological activity of alkaloid compounds. The research on the in vitro and in vivo anticancer activity shows that the medicine is superior to the traditional micromolecule anticancer medicines such as anthracycline antibiotics, cis-platinum, taxol and the like, can effectively inhibit the drug resistance mechanism regulated and controlled by transport protein P-gp, and has system toxicity obviously lower than that of micromolecule medicines (such as no cardiotoxicity, no immunosuppressive side effect and the like). The drug adopts a stable graphene structure and an alkaline nitrogen heterocycle design, overcomes the problems of structural instability, low water solubility and the like of small molecule drugs, and is suitable for systemic drug delivery such as intravenous injection or instillation, body cavity injection, oral administration and the like and interventional therapy modes such as hepatic artery infusion, bladder infusion, pulmonary artery infusion and the like. The ultrathin graphene alkaloid has large specific surface area and contains various in-plane and edge active sites, so that structural optimization and surface functionalization can be further performed, a small-molecule drug and a gene drug are allowed to be loaded, a targeting molecule, a PEG molecule and the like are connected, the ultrathin graphene alkaloid can also be loaded into a common nano-drug carrier, the pharmacokinetics and the therapeutic index of the drug are improved, and multiple choices of treatment schemes such as combined drug therapy, personalized therapy and the like are promoted.

The graphene alkaloid medicine can be conveniently prepared into high-concentration stably-dispersed water-soluble injection, such as glucose injection (about 3.2mg mL)^-1) And no organic cosolvent is needed. The injectionThe injection can be stored at room temperature for a long time without low temperature and light. The injection can also kill various bacteria and pathogenic protozoa with high efficiency. The injection is suitable for various tumor types, including but not limited to: colon cancer, breast cancer, gastric cancer, lung cancer, carcinoma of large intestine, pancreatic cancer, ovarian cancer, prostatic cancer, renal cancer, hepatocarcinoma, brain cancer, melanoma, multiple myeloma, chronic myelogenous leukemia, and lymphoma.

The injection will show specific efficacy in the treatment of tumors as follows, although a large body of clinical trial evidence is also required:

(1) primary tumor metastasis inhibition. The graphene alkaloid medicine can kill latent cancer cells such as tumor stem cells, and has a special effect on inhibiting the diffusion and migration of primary cancer cells. Is particularly suitable for tumor patients who need auxiliary chemotherapy to prevent primary tumor metastasis after surgical resection.

(2) The new adjuvant chemotherapy and the intervention treatment by intratumoral injection. The nano-drug is applied to a systemic administration mode (intravenous injection and cavity injection), is also obviously superior to the traditional small molecular drug in the aspect of intratumoral injection treatment, can obviously reduce the volume of tumor mass, even completely eliminates the tumor, and is particularly suitable for interventional therapy or new auxiliary chemotherapy of the tumor (the volume of the tumor mass is reduced by using the chemotherapy in advance for surgical excision). The advantages of topical treatment benefit from the fact that graphene alkaloids can maintain high intratumoral concentrations for periods of up to 24-36 hours.

In a specific embodiment, the invention provides an anticancer application of graphene alkaloid, wherein the graphene alkaloid nanoparticles can be used as a high-efficiency dual topoisomerase I and II inhibitor to prepare a pharmacologically acceptable anticancer drug or dosage form.

In another preferred embodiment, the graphene alkaloid of the present invention has a broad anti-tumor spectrum, and can be used for the following diseases including but not limited to: colon cancer, breast cancer, gastric cancer, lung cancer, carcinoma of large intestine, pancreatic cancer, ovarian cancer, prostatic cancer, renal cancer, hepatocarcinoma, brain cancer, melanoma, multiple myeloma, chronic myelogenous leukemia, and lymphoma.

In another preferred example, the graphene alkaloid is suitable for systemic administration such as intravenous injection or instillation, body cavity injection, oral administration and the like, and interventional therapy modes such as hepatic artery perfusion, bladder perfusion, pulmonary artery perfusion and the like.

The fourth purpose of the invention is to provide the application of the grapheme alkali in reversing tumor multidrug resistance and inhibiting tumor-resistant cell metastasis.

The graphene base can effectively reverse the drug resistance of at least MCF-7/ADR and HCT-8/PTX cells, and can more effectively inhibit the migration and invasion of cancer cells compared with the common traditional small-molecule anticancer drugs.

The fifth purpose of the invention is to provide the application of the graphene base as a fluorescent probe.

Pharmaceutical compositions and methods of administration

Since the compound of the present invention has excellent inhibitory activity against topoisomerase I and/or topoisomerase II, the compound of the present invention (i.e., graphene alkaloid) and the pharmaceutical composition containing the compound of the present invention as a main active ingredient can be used for the treatment, prevention and alleviation of diseases mediated by topoisomerase I and/or topoisomerase II. According to the prior art, the compounds of the invention are useful for the treatment of the following diseases: cancer. Such cancers include, but are not limited to: colon cancer, breast cancer, gastric cancer, lung cancer, colorectal cancer, pancreatic cancer, ovarian cancer, prostate cancer, renal cancer, liver cancer, brain cancer, melanoma, multiple myeloma, chronic myelogenous leukemia, lymphoma, and the like.

The pharmaceutical composition of the present invention comprises the compound of the present invention or a pharmacologically acceptable salt thereof in a safe and effective amount range and a pharmacologically acceptable excipient or carrier. Wherein "safe and effective amount" means: the amount of the compound is sufficient to significantly improve the condition without causing serious side effects. Typically, the pharmaceutical composition contains 1-1000mg of a compound of the invention per dose, more preferably, 10-500mg of a compound of the invention per dose. Preferably, said "dose" is a capsule or tablet.

"pharmaceutically acceptable carrier" refers to: one or more compatible solid or liquid fillers or gel substances, which are suitable for humansAnd must be of sufficient purity and sufficiently low toxicity. By "compatible" is meant herein that the components of the composition are capable of intermixing with and with the compounds of the present invention without significantly diminishing the efficacy of the compounds. Examples of pharmaceutically acceptable carrier moieties are liposomes, albumin, cellulose and its derivatives (e.g. sodium carboxymethylcellulose, sodium ethylcellulose, cellulose acetate, etc.), gelatin, talc, solid lubricants (e.g. stearic acid, magnesium stearate), calcium sulfate, vegetable oils (e.g. soybean oil, sesame oil, peanut oil, olive oil, etc.), polyols (e.g. propylene glycol, glycerol, mannitol, sorbitol, etc.), emulsifiers (e.g. vomit-ethanol, sodium lauryl sulfate, sodium chloride, sodium lauryl sulfate, sodium chloride, sodium lauryl sulfate

) Wetting agents (e.g., sodium lauryl sulfate), coloring agents, flavoring agents, stabilizers, antioxidants, preservatives, pyrogen-free water, and the like.

The mode of administration of the compounds or pharmaceutical compositions of the present invention is not particularly limited, and representative modes of administration include (but are not limited to): intravenous drip, oral, intratumoral, rectal, parenteral (intravenous, intramuscular or subcutaneous), and topical administration.

Sterile injection solutions for intravenous drip include aqueous glucose solutions or saline containing graphene GA.

Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In these solid dosage forms, the active compound is mixed with at least one conventional inert excipient (or carrier), such as sodium citrate or dicalcium phosphate, or with the following ingredients: (a) fillers or extenders, for example, starch, lactose, sucrose, glucose, mannitol and silicic acid; (b) binders, for example, hydroxymethyl cellulose, alginates, gelatin, polyvinylpyrrolidone, sucrose, and acacia; (c) humectants, for example, glycerol; (d) disintegrating agents, for example, agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain complex silicates, and sodium carbonate; (e) slow solvents such as paraffin; (f) absorption accelerators, e.g., quaternary ammonium compounds; (g) wetting agents, such as cetyl alcohol and glycerol monostearate; (h) adsorbents, for example, kaolin; and (i) lubricants, for example, talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, or mixtures thereof. In capsules, tablets and pills, the dosage forms may also comprise buffering agents.

Solid dosage forms such as tablets, dragees, capsules, pills, and granules can be prepared using coatings and shells such as enteric coatings and other materials well known in the art. They may contain opacifying agents and the release of the active compound or compounds in such compositions may be delayed in release in a certain part of the digestive tract. Examples of embedding components which can be used are polymeric substances and wax-like substances. If desired, the active compound may also be in microencapsulated form with one or more of the above-mentioned excipients.

Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups or tinctures. In addition to the active compounds, the liquid dosage forms may contain inert diluents commonly employed in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, propylene glycol, 1, 3-butylene glycol, dimethylformamide and oils, in particular, cottonseed, groundnut, corn germ, olive, castor and sesame oils or mixtures of such materials and the like.

In addition to these inert diluents, the compositions can also contain adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

Suspensions, in addition to the active compounds, may contain suspending agents as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum methoxide and agar, or mixtures of these substances, and the like.

Compositions for parenteral injection may comprise physiologically acceptable sterile aqueous or anhydrous solutions, dispersions, suspensions or emulsions, and sterile powders for reconstitution into sterile injectable solutions or dispersions. Suitable aqueous and nonaqueous carriers, diluents, solvents or vehicles include water, ethanol, polyols and suitable mixtures thereof.

Dosage forms of the compounds of the present invention for topical administration include ointments, powders, patches, sprays, and inhalants. The active ingredient is mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or propellants which may be required if desired.

The compounds of the present invention may be administered alone or in combination with other pharmaceutically acceptable compounds.

When the pharmaceutical composition is used, a safe and effective amount of the compound of the present invention is suitable for mammals (such as human beings) to be treated, wherein the administration dose is a pharmaceutically-considered effective administration dose, and for a human body with a weight of 60kg, the daily administration dose is usually 1 to 1000mg, preferably 20 to 600 mg. Of course, the particular dosage will depend upon such factors as the route of administration, the health of the patient, and the like, and is within the skill of the skilled practitioner.

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out under conventional conditions or conditions recommended by the manufacturers. Unless otherwise indicated, percentages and parts are percentages and parts by weight.

It is noted that nano-active drugs differ from small molecule cytotoxic drugs in the definition of drug structure. The latter has a limited molecular structural formula or a structural general formula to give strict protection instructions, while the nano toxic drug has no limited chemical structural formula or a structural general formula and can be protected only by describing the main composition, structural characteristics and physicochemical properties of the nano toxic drug. The graphene alkaloid drugs of the present invention are defined by the main structural features described in the summary of the invention and the main physicochemical properties described in the embodiments.

Example 1 acid catalyzed solvothermal Synthesis of graphene alkaloids and Petroleum Ether purification

Julolidine (juliodine) (0.1g) is dissolved in 40mL of absolute ethanol, and 1-3 mL of absolute ethanol is addedAcetic acid (as catalyst) was stirred for 10 min. Then transferring the solution into a 100mL polytetrafluoroethylene high-pressure reaction kettle, and carrying out heat preservation reaction for 1-12 h under the heating condition of 120-230 ℃. And naturally cooling, taking out the graphene alkaloid solution, and separating and purifying petroleum ether. Filtering with a 220nm filter membrane to remove water-insoluble impurities, transferring filtrate containing graphene alkaloid into a flask, performing rotary evaporation to remove a solvent, adding 20mL of petroleum ether into the flask, dissolving unreacted precursors with poor water solubility and good ester solubility and micromolecular impurities under the assistance of ultrasound, performing centrifugal separation to remove the micromolecular impurities dissolved in the petroleum ether, and repeating the purification step for more than 5 times to obtain the pure graphene alkaloid medicament. Adding a certain volume of deionized water to prepare a high-concentration aqueous solution (3.2mg mL)^-1)。

In the above dissolving thermal synthesis, ethanol can be replaced by small molecular weight alcohol solvents such as n-propanol, isopropanol, n-butanol, and isoamylol; the acetic acid can be replaced by organic acid such as propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid, phthalic acid, etc., or responsive organic acid.

The physical and chemical properties of the synthetic drug GA were analyzed, and the results were as follows:

and (3) appearance observation and structural analysis: observed by electron microscopy (figure 2a), the graphene alkali quantum dots have good dispersibility, the transverse particle size is 2.0-8.0 nanometers, and the average particle size is 3.5 +/-0.5 nm. According to atomic force microscopic observation (fig. 2b), most of the graphene is below 1.5 nm in thickness, which indicates that the graphene alkaloid is of a monoatomic layer or a few-layer structure. By high-resolution electron microscopy observation (fig. 2c), the graphene base plane has a complete graphene structure, is formed by fusing dozens to hundreds of benzene rings, has few in-plane defects, is irregular in graphene shape, and has more fine edges and corners at the edge. From the XRD spectrum (FIG. 3a), the graphene base is carbon material, and the (002) crystal face distance is

As can be seen from the Raman spectrum (FIG. 3b), the graphene alkaloid shows the G peak and the D peak which are specific to the carbon material, and the G peak is stronger than the D peak, which indicates that the grapheneThe alkaloid crystallization is good.

Photoelectron spectroscopy analysis of elemental composition and functional groups: photoelectron spectroscopy analysis of elemental composition and functional groups: the nitrogen doping is positioned at the edge of the graphene base and comprises three types of pyridine N, pyrrole N and graphite N. The graphene base contains N10.39 at%, oxygen: 4.69 at% (FIG. 4).

Graphene base Zeta potential analysis: at pH 7.4 and pH 6.5, +45.4eV and +59.9eV, respectively (fig. 5a), indicating that graphene base is protonated, carrying a large amount of positive charge, in neutral physiological media and in a tumor weak acid microenvironment. The Zeta potential of the graphene base also increases with the increase of the concentration thereof, and the Zeta potential changes within the range of +33.2 to +72.3eV within the concentration range of 0.01 to 1.0mg/mL (FIG. 5 b).

Optical property characterization: the graphene alkaloid is easily soluble in water and is also soluble in organic solvents such as ethanol and toluene, and the distribution coefficient is 0.48. Spectroscopic measurements of absorption, fluorescence, excitation, and transient fluorescence of the graphene base solution indicate that the graphene base has the spectral characteristics of semiconductor colloidal quantum dots (fig. 6): the peak value of the absorption band of the visible light region is located at 460nm, the peak value of the fluorescence emission is located at 550nm, the range of the excitation wavelength is wide, and the optimal excitation wavelength is 470 nm. The fluorescence intensity of the graphene base is almost unchanged under different pH conditions. Under continuous 3-hour ultraviolet irradiation, the fluorescence intensity of the graphene alkaloid aqueous solution is almost unchanged, and no photobleaching effect is observed, which indicates that the graphene alkali has high fluorescence stability.

Example 2 chromatographic column separation of graphene alkaloid drugs

The synthesis procedure is the same as that in example 1, except that the separation and purification of petroleum ether is replaced by a neutral alumina chromatographic column separation method. The separation step comprises: the prepared graphene alkaloid solution (in the embodiment, the filtrate after being filtered by a 220nm filter membrane) is subjected to solvent removal by a rotary evaporation method, and then is dispersed in a trichloromethane solution. Then adding the graphene alkaloid solution into a neutral aluminum oxide chromatographic column, using a mixed solution of trichloromethane, cyclohexane and ethanol as an eluent, collecting the separated graphene alkaloid solution according to the characteristic that the graphene alkaloid drug emits yellow fluorescence under an ultraviolet lamp, and performing rotary evaporation on the separated graphene alkaloid solutionThe solvent was removed and a volume of deionized water was added to make a high concentration aqueous solution (3.2mg mL)^-1)。

The physical and chemical properties of the graphene alkaloid prepared in example 1 are consistent with those of the graphene alkaloid.

Example 3 nitrate selective precipitation separation of graphene alkaloid drugs

The acid/alcohol solvothermal synthesis procedure was the same as in example 1, except that the separation and purification of petroleum ether was replaced by nitrate ion selective precipitation separation. The separation step comprises: removing the solvent from 40mL of prepared graphene alkaloid ethanol solution by rotary evaporation, dispersing the graphene alkaloid ethanol solution in 20mL of aqueous solution, adding 0.2g of nickel nitrate for dissolution, separating out the graphene alkaloid from the solution after the solution is kept stand for 10 minutes, enabling the solution to become turbid, and separating out the separated graphene alkaloid by centrifugation, wherein organic small molecular impurities in the aqueous solution are remained in the supernatant and removed. And then, re-dissolving the graphene alkaloid subjected to primary separation in ethanol, and performing secondary separation. And repeatedly separating for three times to obtain the pure graphene alkaloid medicament.

Example 4 Solvothermal Synthesis of graphene alkaloid non-acid catalyst

Similar to the acid catalyzed synthesis of example 1, except that non-organic acid catalysts such as phosphorus pentoxide, phosphorus oxychloride, phosphorus pentachloride, etc. are selected. The method comprises the following specific steps: julolidine (juliodine) (0.1g) is dissolved in 40mL of absolute ethanol, and 0.02-0.1 g of phosphorus pentoxide (or 0.1-1 mL of phosphorus oxychloride or phosphorus pentachloride and the like) is added and stirred for 10 min. Then transferring the solution into a 100mL polytetrafluoroethylene high-pressure reaction kettle, and carrying out heat preservation reaction for 1-12 h under the heating condition of 120-230 ℃. After the reaction is finished, separating and purifying by using a nitrate ion selective sedimentation method.

Example 5 condensation reflux Synthesis of graphene alkaloid

Adding 0.1g of juliodine (juliodine) into 40mL of high boiling point solvent such as isoamyl alcohol, n-octanol or dodecanol, and then adding 1-3 mL of acetic acid, or 0.02-0.1 g of acetic anhydride, or 0.02-0.1 g of phosphorus pentoxide (phosphorus oxychloride, phosphorus pentachloride, etc.) into the solution. And transferring the mixture into a 100mL three-neck flask after the mixture is completely dissolved, heating the mixture in an oil bath kettle in a reflux manner at the temperature of 130-170 ℃, and preserving the heat for 40-120 min. After the reaction is finished, separating and purifying by using a nitrate ion selective sedimentation method.

Example 6 microwave Synthesis of graphene Alkaloids

Julolidine (juliodine) (0.1g) is dissolved in 10mL of absolute ethyl alcohol, 0.1-1 mL of acetic acid is added, and stirring is carried out for 10 min. Then transferring the solution into a 35mL reaction tube, and reacting for 5-60 min under the heating condition of 120-200 ℃. After the reaction is finished, separating and purifying by using a nitrate ion selective sedimentation method.

The physical and chemical properties of the graphene alkaloid prepared in example 1 were consistent.

Example 7 in vitro evaluation of anti-cancer Activity of graphene Alkaloids

The effect of graphene alkaloid drugs on the cell viability of tumor cells, expressed as the percentage of viable cells in total cells, was determined by the MTT method. Will be 5X 10³MCF-7 human breast cancer cells, Hela human cervical cancer cells, 4T1 mouse breast cancer cells, Hgc-27 human gastric cancer cells, A549 human lung cancer cells and HepG-2 human liver cancer cells of each hole are respectively inoculated in a 96-hole plate, and after all the cells are cultured for at least 24 hours, graphene alkaloid medicines with different concentrations and the cells are cultured for 24 hours or 48 hours together. Subsequently, 20. mu.L of MTT solution (5mg mL) was added to each well^-1) After incubation at 37 ℃ for 4 hours, the medium was replaced with 150. mu.L of DMSO, and the absorbance of each well at 490nm was measured using a microplate reader. The dose of graphene alkaloid drug was 1.5, 3, 6, 12 and 24 μ g mL^-1。

Example 8 treatment of intratumoral administration of graphene alkaloids to tumor-bearing mice

In order to evaluate the efficacy of graphene alkaloid, a nude mouse transplantation tumor model (MCF-7) is established and is mixed with small moleculesDrug (DOX) comparisons were made. Drug intratumoral residence time after intratumoral administration was first assessed with a small animal imager. The effect of intratumoral administration of the treatment was then evaluated. Mixing 100 μ L of 10⁷One MCF-7 cell was subcutaneously inoculated on the back of female nude mice for 3-5 weeks. Tumor volume reached 100mm3 around 7 days after inoculation, 15 tumor-bearing nude mice were randomly divided into 3 groups: PBS treatment group (negative control group), DOX treatment group (positive control group), and graphene alkaloid drug treatment group. PBS, DOX and graphene alkaloid drugs with certain volumes are respectively injected into the tumor in tumor (injected once every 7 days), and the volume of the tumor and the weight of the nude mouse are measured every other day.

Example 9 intravenous administration of graphene Alkaloids to tumor-bearing mice

To evaluate the efficacy of graphene alkaloids for systemic administration to various tumor types, 100. mu.L of 107 MCF-7 cells, 5X 10 cells, respectively⁶Hela cell, 10⁶4T1 cells, 5X 10⁶HepG-2 cells and 5X 10⁶One A549 cell was subcutaneously inoculated in the axilla of a female nude mouse for 3-5 weeks. Nude mice were randomly grouped: PBS treatment group (negative control group), DOX treatment group (positive control group), and graphene alkaloid drug treatment group. The tumor volume reaches 100mm about 7 days after inoculation³Intravenous administration was started, once every 3 days, and the volume size of the tumor and the body weight of the nude mice were measured every other day. The number of metastases from the 4T1 tumor was assessed by measuring the number of metastases from the lungs of nude mice.

Example 10 graphene alkaloid in vivo toxicity assessment, pharmacokinetic analysis and Passive Targeted analysis

In vivo toxicity assessment: 12 Balb/c mice were divided into 3 groups of 4 mice each. 200. mu.L of the solution was added at a concentration of 500. mu.g mL^-1The graphene alkaloid drug is injected into 12 Balb/c mice in an intravenous way. Another 12 mice were injected intravenously with 200. mu.L of PBS as a negative control group. Mice were sacrificed on

days

1, 7, and 21 (4 per time point), blood was taken from the eyeball for routine and biochemical blood testing, while organs such as heart, liver, spleen, lung, kidney, etc. were taken, stained after tissue sectioning, photographed, and subjected to histological analysis.

Medicine powerAnd (3) measuring the chemical parameters: firstly, drawing a blood concentration-fluorescence intensity standard curve of the graphene alkaloid in blood. Taking 0.5mL of fresh whole blood of a mouse, adding 1mL of graphene alkaloid medicament aqueous solutions with different concentrations, wherein the final concentrations of the graphene alkaloid medicaments in the blood are respectively 5.00, 10.0, 20.0, 40.0 and 80.0 mu g mL^-1Mixing, centrifuging (10000 rmin)^-1) Separating for 10min, adding a certain amount of PBS solution into 0.2mL of the supernatant respectively, measuring the fluorescence intensity, and deducting the blank value, thereby measuring the relationship between the blood concentration and the fluorescence intensity. The regression equation from the standard curve is 16.34x + 15.471. The results of the measurement of the recovery rate, the precision, the stability and the like show that the blood concentration is 0-100 mu g mL^-1There is a good linear relationship in the range. The graphene alkaloid pharmacokinetic parameters were then measured. Taking 10 normal Balb/c mice, and mixing at 200 μ L concentration of 500 μ gmL^-1The dose of tail intravenous injection is obtained by taking blood from eyeball before administration and after administration for 1,3, 5, 10, 20, 40, 60, 120, 180 and 240min, and centrifuging within 1h (10000 rmin)^-1And 10min), separating serum, adding a certain amount of PBS (phosphate buffer solution) into 0.2mL of serum samples respectively, measuring fluorescence intensity, and deducting blank values to obtain the blood concentration. According to the measured value of the serum fluorescence intensity, the blood concentration in the mouse body at different time points is calculated by a blood concentration-fluorescence intensity regression equation, a pharmaceutical time curve is drawn, and parameters such as T1/2, AUC, CL and the like are calculated by pharmacokinetic software.

Hemolysis experiment: 5mL of fresh ethylenediaminetetraacetic acid (EDTA) -stabilized human whole blood obtained from volunteers was added to 10mL of calcium and magnesium-free PBS. Erythrocytes were separated from the serum after centrifugation for 10 minutes and repeated 5 times. After dilution in 50mL PBS, the red blood cell suspension (0.2mL) was added to the graphene alkaloid drug aqueous solution (0.8 mL). The final concentration range of the graphene alkaloid drug aqueous solution is 25-100 mu gmL^-1. The positive control group and the negative control group were deionized water and PBS, respectively. After incubation at 37 ℃ for 3 hours, centrifugation was carried out for 3 minutes. The absorbance of hemoglobin at 540nm was then measured, with 655nm as a reference. Percent hemolysis was calculated using the formula.

Passive targeting assessment: HepG-2, Hela and 4T1 tumorAbout 7 days after the tumor model is established, when the tumor volume reaches 200mm³When the injection is carried out, 250. mu.g mL of the injection is injected into a vein ^-1100 μ L of graphene alkaloid drug, observed and photographed with an in vivo imaging system. The excitation wavelength was 480nm and the fluorescence collection wavelength was 570 nm. Photographs were taken at 0min, 5min, 30min, 1h, 2h, 4h, 8h and 24h post injection, respectively. Simultaneously, the nude mice were sacrificed after intravenous injection of graphene alkaloid drugs for 0, 2, 4, 8 and 24h, and the major organs were taken out for fluorescence photographing with an in vivo imaging system.

Example 11 study of graphene base drug binding to DNA major groove region

First, 30. mu.g mL-1 of DNA and 30. mu.g mL of DNA were mixed^-1After incubating the methyl green for 20min, three characteristic peaks of the methyl green binding to DNA were measured by circular dichroism. Different concentrations of GA drug were then added to the mixed solution of methyl green and DNA, and the circular dichroism spectrum was measured, and the intensity of three characteristic peaks was observed as the concentration of GA drug increased.

Example 12 evaluation of damage of graphene Alkaloids to DNA

Taking normal Hela cells, and respectively culturing the cells with complete culture media. When the cell growth state is good, grouping according to experiment, and administering according to IC₅₀And 4 × IC₅₀The drug concentration of (a) was added to the medium and a set of blank controls was set. Comet experiments were performed after 48h of treatment.

Example 13 evaluation of the inhibitory Effect of graphene Alkaloids on topoisomerase I and II

In a reaction system (Topo I: pBR322 DNA, Tris, DTT, MgCl)₂KCl and BSA; topo II α: pBR322 DNA, ATP, Tris, NaCl, MgCl₂KCl, EDTA and BSA), diluted concentrations of graphene alkaloid drug (1.5, 3, 6, 12 and 24. mu.g mL) were added^-1) Or 100 μ M positive control (Topo I: CPT, Topo II α: VP-16), mixing, adding 1unit Topo I/Topo II alpha, blowing carefully, mixing, placing in 37 deg.C water bath for 30min, adding 1 μ L10% SDS to terminate reaction, mixing with 1.0% (w/v) agarose gel, and adding 5Vcm^-1Electrophoresed under the conditions of 1h, using 0.5. mu.g mL^-14s Green nucleic acid dye is used for photographing and observing by using a gel imager after being dyed for 15min in a dark place.

Example 14 graphene alkaloid reversal of drug resistance of drug-resistant cells to Small molecule drugs

The MTT method is used for detecting the effect of the graphene alkaloid on the survival rate of MCF-7/ADR and HCT-8/PTX cells, and DOX and PTX are used as positive controls. The cell viability and the semi-Inhibitory Concentration (IC) of graphene alkaloids were subsequently measured after incubation with DOX, PTX, respectively, and MCF-7/ADR, HCT-8/PTX cells₅₀). Direct observation of graphene alkaloid drugs by confocal laser microscopy (1/3 × IC)₅₀) Can target the nucleus of drug-resistant cells and can help DOX (10. mu.g mL)^-1) Into MCF-7/ADR cells.

Example 15 evaluation of the ability of graphene alkaloids to inhibit cancer cell migration and invasion

2 x 10 to⁵4T1, A375, HepG2 and PANC-1 cells were seeded separately in 6-well plates and incubated for 24 hours until the cells were confluent, followed by lining up the middle of each well of the 6-well plate with a 1mL pipette tip, followed by addition of graphene base (3.0. mu.g mL of mL)^-1) After 24 hours of incubation, the ability to inhibit cell migration was assessed by photographing with a fluorescence microscope before adding graphene base and after 24 hours of incubation.

2 x 10 to⁴4T1 cells were seeded in the upper chamber of a Transwell, 1640 medium without serum was added to the upper chamber, 1640 medium with 10% serum was added to the lower chamber, and then graphene base was added to the upper chamber, and after incubation for 6 hours, the lower chamber was removed, and the ability of graphene base to inhibit cell migration was evaluated by observing and photographing with a fluorescence microscope after crystal violet staining.

For the invasion assay, the procedure was essentially the same as for the migration assay, except that a layer of matrigel was applied to the upper chamber, and then 4T1 cells were seeded into the upper chamber, and the incubation time after the addition of graphene base was 24 hours.

Example 16 evaluation of the ability of graphene alkaloids to inhibit metastasis of cancer cells in vivo

To assess the ability of the graphenes to inhibit cancer cell metastasis, we injected 4T1 cells stably transfected with luciferase (4T1-Luc) intravenously into nude mice, followed by intravenous injection of eachGA(5mg kg^-1) And DOX (2.5mg kg)^-1) The injection is carried out once every 7 days, the transfer condition of the 4T1-Luc cells in vivo is observed by in vivo bioluminescence imaging every 5 days, and a substrate of luciferase is injected intraperitoneally 15 minutes before photographing. After 15 days, the lungs of the nude mice were taken out, photographed, and quantitatively observed for lung metastasis of cancer cells.

Example 17 labeling of DNA with graphene alkaloid as fluorescent Probe

Firstly, preparing an agarose solution with the concentration of about 1%, weighing 0.36g of agarose, pouring the agarose into a conical flask, adding 30mL of 1 XTAE buffer solution, heating the agarose solution in a microwave oven for 1min, cooling the agarose solution at room temperature for 10min, keeping the solution in a warm state, adding 10 mu L of agarose solution with the concentration of 1-3 mg mL^-1Carefully shaking the conical flask, adding the conical flask into a gel-making mold, cooling to obtain a gel-like solution, placing the gel block on a horizontal electrophoresis device after about 30-60 min, adding 5 mu L of DNA marker (DL 2000) into a sample tank, closing an electrophoresis tank cover after the sample is added, switching on a power supply, and carrying out electrophoresis at a voltage of 120V for 30 min. And after the electrophoresis is finished, taking out the gel block, and taking a picture of the gel block by using a gel electrophoresis imaging instrument for analysis, wherein the wavelength range of exciting light is 350-500nm, and the wavelength of emitting light is 530-560 nm. Commercial nucleic acid dyes PI, SYTO17, Hoechst33258 and methyl green MG were used as positive controls.

Example 18 use of graphene Alkaloids as fluorescent probes for Nuclear labelling of Living cells

Will be about 2X 10⁵Inoculating Hela cells into confocal dish, culturing in incubator for at least 24 hr, adding 100 μ L of 20 μ g mL^-1After incubating the GA drug solution for 5min, the culture medium was poured off, and 1mL of PBS solution was added to wash the cells for 3 times. Then, fluorescence observation and image shooting are carried out on the GA drug targeting cell nucleus by using a confocal microscope, the excitation wavelength can be 405nm, 488nm or 543nm, and the corresponding detection wavelengths are respectively 410-500nm, 500-600nm and 550-620 nm. The nucleic acid dye SYTO17 is used as a positive control, the excitation wavelength is 633nm, and the detection wavelength is 640-700 nm.

The MTT cytotoxicity assay was performed on the graphene alkaloid GA (see examples for test methods) and the results were as follows:

GA has wide anticancer activity on randomly selected human tumors (osteosarcoma, pancreatic cancer, liver cancer, lung cancer, breast cancer, cervical cancer, gastric cancer, colorectal cancer, melanoma and the like), namely broad-spectrum characteristics. Especially, the compound shows higher anticancer activity to refractory cancers with high malignancy degree, such as osteosarcoma (MG63), pancreatic cancer (Panc-1) and liver cancer (HepG-2) and lung cancer (A549) with highest mortality rate (figures 7a and 7 b).

A nude mouse transplanted tumor model is established, and the in vivo anticancer efficacy of the synthetic drug is evaluated (the test method is shown in examples 8-9), and the results are as follows:

pharmacodynamic analysis of intratumoral administration: the treatment effect of the GA intratumoral administration is obviously superior to that of the traditional small molecule drugs. A comparison of the efficacy of GA and DOX intratumoral administration revealed a low dose (0.75mg kg)^-1) The inhibition rate of GA on MCF-7 tumor was 100%, while the high dose of positive control group was doxorubicin (1.25mg kg)^-1) The inhibition rate was only 72.4% (fig. 12). The result shows that the GA is more suitable for being applied to local treatment modes such as interventional therapy of hepatic artery perfusion, bladder perfusion, pulmonary artery perfusion and the like or peritoneal perfusion than the micromolecular anticancer drugs.

Pharmacodynamic analysis of intravenous injection: the safe treatment effect of GA on various solid tumors is also obviously better than that of the traditional small molecule drugs (relevant data are shown in the following table). The in vivo efficacy and toxicity of GA and doxorubicin were first compared. When the safe and effective dose of GA is 5.0mg kg^-1The growth inhibition rates of HepG-2, a549, Hela and 4T1 tumors were 73.1%, 71.8%, 68.5% and 69.8%, respectively, and the mouse weight was not decreased compared to the untreated group, but the weight of some mice was increased (fig. 13). When the doxorubicin dose was reduced to half of GA (2.5mg kg)^-1) The reduction rate of the weight of the rat reaches 20%, and high toxic and side effects (mainly cardiotoxicity) are shown. Due to the dose-limiting toxicity, the growth inhibition rates of adriamycin on HepG-2, A549, Hela and 4T1 were only 40.9%, 38.7%, 39.1% and 33.7%, respectively, which is far lower than the safe treatment effect of GA. For 4T1 tumor, the inhibition rate of GA lung metastasis was 97.5%, while that of adriamycin was only 35.9%. This result is consistent with the results of in vitro cancer cell migration inhibition experiments: cancer cell migration is completed within 24h in the presence of GAFull block, whereas DOX drugs, similar to the control group, were almost completely unable to inhibit cancer cell migration (fig. 15). The GA was then compared to other first-line clinical drugs paclitaxel and cisplatin. Under the same dosage condition with GA, the growth inhibition rate of 4T1 tumor by paclitaxel was only 28.5%, which is much lower than 69.8% of GA. At the highest safe dose (2.0mg kg)^-1) Under the condition, the growth inhibition rate of the cisplatin to the 4T1 tumor is 59.9 percent, and is also lower than that of GA. Finally, to examine the in vivo efficacy of GA on the drug-resistant cell line, the curative effects of GA and paclitaxel on the drug-resistant cell line HCT-8/PTX were also compared, and it was found that paclitaxel was not sensitive to drug-resistant colorectal cancer (treatment was ineffective), whereas GA was not limited by drug resistance and the inhibition rate was 60.2%. Taken together, these results, the low-toxicity GA showed strong advantages in treating tumor primary, metastatic and drug-resistant tumors compared to small molecule chemotherapeutic drugs.

The pharmacokinetic profile of the above synthetic drugs was examined (see examples for test methods) and the results are as follows:

GA is structurally stable and not metabolically degraded, but due to its small size, it is easily excreted by the kidneys and liver, so GA has a short half-life of only 62 minutes (fig. 16). In vivo imaging shows that the graphene alkaloid drug injected intravenously has important enrichment in tumor regions, and shows a certain passive targeting ability (fig. 17).

The safety of the above synthetic drugs was evaluated, and the results were as follows:

the systemic toxicity and metabolic pathways of the graphene alkaloid in mice are researched through in vivo fluorescence imaging after intravenous injection of the graphene alkaloid. It can be seen that GA is mainly excreted out of the body through kidney and liver metabolism, and no obvious GA fluorescence signal is basically seen in the body 24h after the injection of the drug, which indicates that the graphene alkaloid drug can be quickly excreted out of the body. Subsequently, it can also be seen by ex vivo organ fluorescence imaging that it is excreted mainly through the kidney and liver, without significant accumulation in other organs (heart, spleen, lung) (fig. 18). Histological, hematology, hematobiochemistry and hemolysis experimental analyses showed that the blood biochemistry and hematology indices of the treated mice were within the normal range, and no significant difference from the control group was observed, and no acute or chronic myelosuppression problems caused by GA were observed (fig. 19-21). It can be seen that the graphene alkaloid medicament has no obvious toxic or side effect on main organs.

The mechanism of action of the above synthetic drugs was analyzed at the molecular and cellular level (see examples 11-13 for methods) and the results were as follows:

1) the round two chromatography method was used to investigate whether the GA drug could squeeze out the region binding competitively to the small molecule dye methyl green in the major groove region of DNA. It was found (fig. 9) that after methyl green interacts with DNA, three characteristic peaks appear in the circular dichroism chromatogram, and the intensities of the three characteristic peaks decrease with the increase of GA drug concentration, indicating that the GA drug competitively extrudes methyl green out of the DNA major groove region, thereby proving that the GA drug binds to the DNA major groove region.

2) The topoisomerase inhibitory activity of GA drugs was investigated by agarose gel electrophoresis. The experimental findings (fig. 10,11) that neither topoisomerase I nor II were able to uncoil plasmid DNA in the presence of graphene alkaloids, were similar to the positive controls camptothecin CPT (Topo I inhibitor) and etoposide VP-16(TopoII inhibitor), indicating that GA is a dual inhibitor of topoisomerase I and II. By comparing the results of the agarose gel electrophoresis at different concentrations of GA drug, it was found that GA drug can produce significant inhibitory activity at low concentrations of 1/6 at the CPT concentration or 1/10 at the VP-16 concentration. This result is consistent with the results of the cytotoxicity test.

3) Detection of GA-induced DNA damage. Comet experiments prove that the graphene alkaloid drug can cause the DNA of Hela cells to have a trailing phenomenon under the condition of half-lethal concentration, which shows that the anti-cancer activity of the graphene alkaloid has a direct relation with DNA damage.

GA anticancer drugs combine the unique biological activities of graphene alkaloids with the unique pharmacological activities of alkaloid compounds. The research on the in vivo and in vitro anticancer activity shows that the medicine is superior to the traditional micromolecular anticancer medicines such as anthracycline antibiotics, cis-platinum, taxol and the like, and the systemic toxicity is obviously lower than that of the micromolecular medicines (such as no cardiotoxicity, no immunosuppressive side effect and the like). The drug adopts a stable graphene structure and an alkaline nitrogen heterocycle design, overcomes the problems of structural instability, low water solubility and the like of small molecule drugs, and is suitable for systemic drug delivery such as intravenous injection or instillation, body cavity injection, oral administration and the like and interventional therapy modes such as hepatic artery infusion, bladder infusion, pulmonary artery infusion and the like. The ultrathin graphene alkaloid has large specific surface area and contains various in-plane and edge active sites, so that structural optimization and surface functionalization can be further performed, a small-molecule drug and a gene drug are allowed to be loaded, a targeting molecule, a PEG molecule and the like are connected, the ultrathin graphene alkaloid can also be loaded into a common nano-drug carrier, the pharmacokinetics and the therapeutic index of the drug are improved, and multiple choices of treatment schemes such as combined drug therapy, personalized therapy and the like are promoted.

The ability of the above synthetic drugs to reverse multidrug resistance was tested (test methods see example 14) and the results were as follows:

as can be seen from the confocal fluorescence microscope observation image, DOX (10. mu.g mL)^-1) Can enter the nucleus of drug-sensitive cells (MCF-7) but not the nucleus of drug-resistant cells (MCF-7/ADR). Graphene base (0.5. mu.g mL)^-1) Can enter the cell nucleus of drug sensitive cells and drug resistant cells. While when both acted together on the resistant cells, DOX could enter the nucleus of the resistant cells (fig. 22), demonstrating that graphene base could reverse the multidrug resistance of the resistant cells. When low concentrations of graphene base (without significant cytotoxicity) and small molecule drugs were incubated with the drug-resistant cells to show significant cytotoxicity, the graphene base could reduce the DOX resistance index of MCF-7/ADR cells from 155.95 to 0.84, and the graphene base could reduce the PTX resistance index of HCT-8/PTX from 88.41 to 3.29 (FIGS. 23 and 24).

The ability of the above synthetic drugs to inhibit metastasis of cancer cells was examined (see examples 15-16 for test methods), and the results were as follows:

scratch experiments showed that graphene base was highly effective in inhibiting cell migration of various cancer cells (4T1, A375, HepG2 and PANC-1) (FIG. 25). Transwell experiments also confirm that the grapheme alkali can effectively inhibit the cell migration and the cell invasion of 4T1 cells (figures 26 and 27), and the inhibition effect is obviously higher than that of small-molecule chemotherapeutic drugs (DOX and PTX).

In vivo, after a circulating tumor metastasis model is constructed by intravenous injection of 4T1-Luc cells, graphene or a small-molecule chemotherapeutic drug DOX is intravenously injected, and in vivo bioluminescence imaging is utilized on

days

5, 10 and 15 after administration, so that the graphene can be clearly seen to be capable of efficiently inhibiting the pulmonary metastasis of the 4T1-Luc cells (figure 28), and the inhibition effect of the graphene is obviously better than that of the DOX.

The ability of the synthesized graphene base to serve as a fluorescent probe for labeling DNA was tested (see example 17 for test methods), and the results are as follows:

gel electrophoresis experiments prove that graphene base is used for DNA staining imaging, DNA bands with different molecular weights can be clearly displayed, and the detection effect is obviously superior to that of commercial nucleic acid dyes PI, SYTO17, Hoechst33258 and MG (figure 29).

The synthetic graphene-based GA fluorescent probe was used for continuous stable imaging labeling of nuclei of living cells (see example 18 for test methods), and the results were as follows:

the use of a confocal microscope to observe GA for nuclear imaging of living cells, in contrast to the imaging area of the commercial nucleic acid dye SYTO17 (FIG. 30), revealed that both GA and SYTO17 gave clear nuclear imaging, and that the imaging areas were identical, indicating that GA may be used as a nucleic acid dye for nuclear imaging of living cells. If the duration of the light excitation exceeds 10 minutes (FIG. 31), it was found that the nuclear imaging effect of GA was unchanged, whereas the commercial nucleic acid dye lost its imaging ability due to severe photo-bleaching, indicating that GA is very stable for nuclear imaging of living cells.

The embodiments of the present invention have been described in detail, but the embodiments are merely examples, and the present invention is not limited to the embodiments described above. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the present invention.

Claims

1. The graphene base is characterized by comprising a nano-scale graphene planar structure, wherein the size of the graphene planar structure is 1-10 nm, and the thickness of the graphene planar structure is 0.34-3.4 nm; the graphene material further comprises a nitrogen heterocyclic ring cluster structure which is covalently bonded to the edge of the graphene planar structure, the nitrogen heterocyclic ring cluster structure comprises a pyridine ring, a pyrrole ring, a phenol ring or a combination thereof, the nitrogen heterocyclic ring cluster structure comprises a combination of 10-50 heterocyclic rings, and the atomic ratio of N in the pyridine ring structure, N in the pyrrole ring structure and N in the graphite N ring structure is pyridine N: pyrrole N: graphite N ═ (2.0 to 5.0): (0.1-0.8): 1; the content of N in the graphene alkali is 5-20 at%.

2. The graphene base targeting the DNA major groove and inhibiting topoisomerase according to claim 1, wherein the graphene base has a quasi-molecular weight of 2000-20000.

3. The DNA major groove-targeted topoisomerase inhibiting graphene base according to claim 1, wherein the graphene base has a Zeta potential of +33.2 to +72.3eV at physiological pH (pH 6.5 to 7.4) and/or at a concentration range of 0.01 to 1.0 mg/mL.

4. The graphene base targeting the DNA major groove and inhibiting topoisomerase according to claim 1, wherein the maximum absorption of the aqueous solution of graphene alkaloid is at 430-480 nm and/or the fluorescence emission is at 530-560 nm.

5. A method for preparing the graphene base targeting the DNA major groove and inhibiting topoisomerase according to any one of claims 1 to 4, comprising the steps of:

wherein the precursor is Julolidine (juliodine); the catalyst is organic acid and/or anhydride thereof, and/or a phosphorus-containing compound;

the mass volume ratio (mg: ml) of the precursor to the alcohol solvent is (2.0-3.0) to 1;

when the catalyst is liquid, the volume ratio of the catalyst to the alcohol solvent is 1 (4-40); when the catalyst is a solid, the mass-to-volume (mg: ml) ratio of the catalyst to the alcohol solvent is 1: (40-400).

6. The preparation method according to claim 5, wherein in the step (a), the organic acid catalyst is selected from one or more of acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid and phthalic acid.

7. The preparation method according to claim 5, wherein in step (a), the phosphorus-containing compound is selected from one or more of phosphorus pentoxide, phosphorus oxychloride and phosphorus pentachloride.

8. The method according to claim 5, wherein in step (a), the alcoholic solvent is selected from one or more of ethanol, n-propanol, isopropanol, n-butanol, and isoamyl alcohol.

9. The method according to claim 5, wherein the reaction temperature in step (a) is 100 to 300 ℃ and the reaction time is 0.05 to 24 hours.

10. The method of claim 5, further comprising the steps of:

11. The method of claim 10, wherein the post-treating step is: (i) a post-treatment based on petroleum ether extraction, (ii) a post-treatment based on column chromatography separation, and/or (ii) a post-treatment based on salt precipitation centrifugation.

12. Use of the graphene base according to any one of claims 1 to 4 for targeting the DNA major groove and inhibiting topoisomerase, wherein (i) the graphene base is used for preparing an inhibitor for inhibiting topoisomerase; and/or (ii) for the manufacture of a medicament or composition thereof for the treatment and/or prevention of cancer.

13. The use of a graphene base to target the DNA major groove and inhibit topoisomerase according to claim 12 wherein the topoisomerase comprises both topoisomerase I and II types.

14. The use of graphene base for targeting the DNA major groove and inhibiting topoisomerase according to claim 12, wherein said pharmaceutical composition comprises said graphene base and a pharmaceutically acceptable carrier or a small molecule drug or an antibody or an immune drug.

15. The use of graphene base to target the DNA major groove and inhibit topoisomerase according to claim 12 wherein said cancer comprises: colon cancer, breast cancer, gastric cancer, lung cancer, carcinoma of large intestine, pancreatic cancer, ovarian cancer, prostatic cancer, renal cancer, hepatocarcinoma, brain cancer, melanoma, multiple myeloma, chronic myelogenous leukemia, blood tumor, and lymphoma.

16. The use of graphene base to target the DNA major groove and inhibit topoisomerase according to claim 12 wherein the treatment and/or prevention comprises: reversing the resistance of resistant cells and/or inhibiting cancer cell metastasis.

17. The application of the graphene base is characterized in that the graphene base can target DNA major groove, and comprises a nano-scale graphene planar structure, wherein the size of the graphene planar structure is 1-10 nm, and the thickness of the graphene planar structure is 0.34-3.4 nm; the graphene material further comprises a nitrogen heterocyclic ring cluster structure which is covalently bonded at the edge of the graphene planar structure, the nitrogen heterocyclic ring cluster structure comprises a pyridine ring, a pyrrole ring, a phenol ring or a combination thereof, the nitrogen heterocyclic ring cluster structure comprises a combination of 10-50 heterocyclic rings, and the atomic ratio of N in the pyridine ring structure, N in the pyrrole ring structure and N in the graphite N ring structure is pyridine N: pyrrole N: graphite N ═ (2.0 to 5.0): (0.1-0.8): 1; the content of N in the graphene alkali is 5-20 at%; the application refers to the application of the grapheme alkali in preparing a reversal agent for reversing the multidrug resistance of the tumor and/or the application in preparing an inhibitor for inhibiting cancer cell metastasis.

18. The use of the graphene base according to claim 17, wherein the tumor multidrug resistance comprises one or more of breast cancer doxorubicin resistance, colon cancer paclitaxel resistance and cervical cancer cisplatin resistance.

19. A fluorescent probe for labeling nucleic acids and/or cell nuclei, comprising a graphene base; the graphene base can target a DNA major groove and comprises a nano-scale graphene planar structure, the size of the graphene planar structure is 1-10 nm, and the thickness of the graphene planar structure is 0.34-3.4 nm; the graphene material further comprises a nitrogen heterocyclic ring cluster structure which is covalently bonded to the edge of the graphene planar structure, the nitrogen heterocyclic ring cluster structure comprises a pyridine ring, a pyrrole ring, a phenol ring or a combination thereof, the nitrogen heterocyclic ring cluster structure comprises a combination of 10-50 heterocyclic rings, and the atomic ratio of N in the pyridine ring structure, N in the pyrrole ring structure and N in the graphite N ring structure is pyridine N: pyrrole N: graphite N ═ (2.0 to 5.0): (0.1-0.8): 1; the content of N in the graphene alkali is 5-20 at%.

20. The fluorescent probe of claim 19, wherein the fluorescent probe can be used for labeling isolated DNA or nuclei in living cells.