Graphene quantum dot material as well as preparation method and application thereof

Abstract

The invention discloses a graphene quantum dot material as well as a preparation method and application thereof, and belongs to the technical field of biomedical materials. The preparation method comprises the following steps: S1, carrying out hydrothermal reaction on a mixed solution of mesoporous SiO2 and a carbon source to obtain a product I; s2, the product I and a fluoride solution are mixed to remove SiO2, and a product II is obtained; and S3, refining the product II to obtain the graphene quantum dot material. The carbon source is selected from at least one of triammonium citrate, diammonium hydrogen citrate, citric acid, folic acid, urea, thiourea and dicyanodiamine; the fluoride is selected from ammonium bifluoride and / or hydrogen fluoride. The particle size of the graphene quantum dot material provided by the invention is 15-30nm, the distribution is controllable, and the raw materials are easy to obtain; the prepared platinum nanoparticle / graphene quantum dot composite nanomaterial is high in solubility, stable in physical and chemical properties and remarkable in chemotherapy effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biological medical materials, and particularly relates to a graphene quantum dot material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, the chemotherapeutic effect of platinum nanoparticles (PtNPs) has attracted widespread attention. In the special microenvironment of tumors (such as a relatively high acidity and a relatively high concentration of hydrogen peroxide), high-activity PtNPs with a surface effect are oxidized and decomposed to release ion platinum or related divalent platinum complexes that are toxic to cancer cells, thereby producing a chemotherapeutic effect. On the other hand, in normal neutral or weakly alkaline body fluids, PtNPs are difficult to be oxidized and decomposed, and are accumulated in tumor tissues through the enhanced permeability and retention effect (EPR), thereby showing a smaller toxic side effect than platinum molecular drugs. In addition, PtNPs are a multifunctional anti-tumor drug and also have special properties such as artificial enzymes and high-energy ray sensitization. Therefore, compared with commonly used platinum molecular drugs such as cisplatin and oxaliplatin, PtNPs with a chemotherapeutic effect show lower toxic side effects and also show obvious inhibition of some tumors that are resistant to platinum molecular drugs. PtNPs chemotherapy drugs are expected to become the next generation of platinum anti-cancer drugs.

[0003] Graphene quantum dots (GQDs) are a new type of zero-dimensional carbon-based nanomaterial composed of small graphene fragments (2-100 nm) and have unique advantages in the field of tumor diagnosis and treatment, such as special fluorescence produced by quantum confinement, rich active sites, adjustable physical and chemical properties, photoactive oxygen, high-efficiency photothermal effect, good solubility, high biocompatibility, and strong binding capacity with proteins and DNA. Therefore, as a multifunctional nanoplatform, GQDs show great application prospects in tumor diagnosis, cell imaging, drug loading and release, photodynamic therapy, near-infrared photothermal therapy, and the like. The use of high-biocompatibility GQDs to protect PtNPs with a chemotherapeutic effect can effectively improve the dispersibility and solubility of the drug and increase the accumulation of PtNPs@GQDs chemotherapy drugs in tumor tissues through the EPR effect, so as to passively target cancer cells.

[0004] However, the controllability of the particle size of graphene quantum dot materials affects the compounding effect of the graphene quantum dot materials and the PtNPs, which further affects the medical effect of the PtNPs in anti-tumor drugs. SUMMARY

[0005] In view of this, the present application provides a graphene quantum dot material and a preparation method and application thereof, and the main purpose is to solve the technical problem of uncontrollable particle size distribution of graphene quantum dot materials.

[0006] In one aspect, the present application provides a preparation method of a graphene quantum dot material, which comprises the following steps:

[0007] S1: a mixed solution of mesoporous SiO2 and a carbon source is subjected to a hydrothermal reaction to obtain product I;

[0008] S2: the product I is mixed with a fluoride solution to remove the SiO2 to obtain product II;

[0009] S3: the product II is subjected to purification to obtain the graphene quantum dot material;

[0010] The carbon source is selected from at least one of the following: ammonium citrate, hydrogen diammonium citrate, citric acid, folic acid, urea, thiourea, dicyanediamine.

[0011] The fluoride is selected from ammonium hydrogen fluoride and / or hydrogen fluoride.

[0012] The present application uses a hard template method to achieve controllable preparation of graphene quantum dots; for graphene quantum dots with a particle size of 10-30 nm, "silicon dioxide with an average pore size of 15-50 nm" is used as a hard template to prepare graphene quantum dots with a particle size of 10-30 nm. Alternatively, the average pore size of the mesoporous SiO2 is 15-50 nm.

[0013] Alternatively, the average pore size of the mesoporous SiO2 is selected from any value or a range value between any two values selected from 15, 20, 25, 30, 35, 40, 45, and 50, in units of nm.

[0014] Alternatively, the mixing ratio of the mesoporous SiO2 and the carbon source is 6g:18-45mmol.

[0015] Alternatively, the mixing ratio of the mesoporous SiO2 and the carbon source is selected from 6g:18mmol, 6g:20mmol, 6g:25mmol, 6g:28mmol, 6g:30mmol, 6g:35mmol, 6g:38mmol, 6g:40mmol, or 6g:45mmol.

[0016] Alternatively, the reaction temperature of the hydrothermal reaction in step S1 is 200-220℃, and the reaction time is 8-12h.

[0017] Alternatively, the reaction temperature is selected from any value or a range value between any two values selected from 200, 205, 210, 215, and 220, in units of ℃.

[0018] Optionally, the reaction time is selected from any value or a range value between any two values of 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, in units of hours (h).

[0019] Optionally, the specific process of step S1 comprises: adding the component I and deionized water into the system in which the mesoporous SiO2 is dispersed, to form the mixed solution, and the mixed solution is subjected to ultrasonic dispersion and dissolution, and then the hydrothermal reaction is performed.

[0020] Optionally, the ultrasonic dissolution time is 5-20 minutes.

[0021] Optionally, the ultrasonic dissolution time is selected from any value or a range value between any two values of 5, 8, 10, 12, 15, 20, in units of minutes (min).

[0022] The ultrasonic dissolution time in the application can be adjusted according to the actual dissolution condition.

[0023] Optionally, the reaction solution after the hydrothermal reaction in step S1 is subjected to cooling and vacuum rotary evaporation to obtain the product I.

[0024] Optionally, the product I in step S2 is immersed in the component II solution at room temperature, and the SiO2 is removed.

[0025] Optionally, the product II in step S3 is subjected to centrifugal separation, vacuum rotary evaporation, freeze-drying to remove solvent water, and anhydrous ethanol washing, and the product is the graphene quantum dot material.

[0026] The anhydrous ethanol washing times in the application can be adjusted according to the actual washing effect of the product.

[0027] In a second aspect, the application provides a graphene quantum dot material, which is prepared by the above preparation method.

[0028] Optionally, the particle size of the graphene quantum dot material is 10-30 nm.

[0029] Optionally, the particle size of the graphene quantum dot material is selected from any value or a range value between any two values of 10, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, in units of nm.

[0030] The graphene quantum dot of the application is a light yellow graphene quantum dot which is insoluble in ethanol.

[0031] In a third aspect, the present application provides application of the graphene quantum dot material in tumor diagnosis, cell imaging, drug loading and release, photodynamic therapy or near-infrared photothermal therapy.

[0032] Optionally, the graphene quantum dot material is applied in an anti-tumor drug carrier.

[0033] Optionally, the graphene quantum dot material is loaded with a targeting molecule as a carrier.

[0034] Optionally, the targeting molecule is selected from at least one of biotin, folic acid, RGD peptide, hyaluronic acid and TAT cell-penetrating peptide.

[0035] In a fourth aspect, the present application provides a platinum nanoparticle / graphene quantum dot composite nanomaterial, wherein the platinum nanoparticles are dispersed in an amorphous graphene quantum dot matrix in the form of aggregates; and the graphene quantum dots are selected from the graphene quantum dot material.

[0036] The composite nanomaterial of the present application protects platinum nanoparticles with a chemotherapy effect by using high biocompatible graphene quantum dots, effectively improves the dispersibility and solubility of the drug, and increases the accumulation of platinum nanoparticle / graphene quantum dot composite drugs in tumor tissues through enhanced permeability retention effect, and passively targets cancer cells. In addition, the graphene quantum dots as nanocarriers can load bioactive agents and targeting agents (antibodies, folic acid, RGD peptide, hyaluronic acid, TAT cell-penetrating peptide, etc.), improve the active targeting ability of the composite drug, enhance the tumor treatment effect and reduce the toxic side effects.

[0037] In a fifth aspect, the present application provides a preparation method of the platinum nanoparticle / graphene quantum dot composite nanomaterial, comprising: obtaining graphene quantum dots; and subjecting a mixture of the graphene quantum dots, a platinum source and a reducing agent to thermal reduction to obtain the composite nanomaterial; characterized in that the graphene quantum dots are prepared by any one of the preparation methods.

[0038] Optionally, the reducing agent is selected from at least one of methanol and ethanol.

[0039] Optionally, the platinum source is selected from at least one of sodium chloroplatinite, potassium chloroplatinite, ammonium chloroplatinite, platinum tetrachloride, chloroplatinic acid and sodium chloroplatinate.

[0040] The present application synthesizes platinum nanoparticle / graphene quantum dot chemotherapy drugs with high solubility in a kilogram level by a simple thermal reduction synthesis method. In the preparation process, no toxic reducing agent needs to be added additionally, and the graphene quantum dots simultaneously serve as a multifunctional auxiliary matrix and a stabilizer for superfine platinum nanoparticles with a chemotherapy effect.

[0041] In a sixth aspect, the present application provides the use of the platinum nanoparticle / graphene quantum dot composite nanomaterial in the preparation of an antitumor drug.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] 1) The graphene quantum dot material provided by the present application has a particle size of 10-30 nm and a controllable distribution.

[0044] 2) The raw materials for preparing the graphene quantum dot material provided by the present application are all industrial raw materials, and the graphene quantum dot material can be produced on a large scale.

[0045] 3) The graphene quantum dot material provided by the present application has a controllable particle size and a wider application range as a drug carrier.

[0046] 4) The platinum nanoparticle / graphene quantum dot composite nanomaterial provided by the present application has high solubility, stable physicochemical properties, and significant chemotherapeutic effect. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a powder diffraction pattern of the GQDs provided by Example 1 of the present application;

[0048] Figure 2 is a transmission electron microscope image of the GQDs provided by Example 1 of the present application.

[0049] Figure 3 is a transmission electron microscope image of the PtNPs@GQDs provided by Example 4 of the present application. DETAILED DESCRIPTION

[0050] The present application will be described in detail below with reference to the examples, but the present application is not limited to these examples.

[0051] Unless otherwise specified, the raw materials in the examples of the present application are purchased through commercial channels.

[0052] The mesoporous silica used in the examples is from Xi'an Ruiyi, has a particle size of 200 nm, and a pore size of 20 nm.

[0053] In the examples, X-ray powder diffraction phase analysis (XRD) is performed on a Miniflex II X-ray diffractometer of Rigaku Company at 30 kV and 15 mA, with a Cu target and a Kα radiation source.

[0054] In the examples, the transmission electron microscope and high-resolution transmission electron microscope analysis are performed using a Tecnai G2 F20 S-TWIN TMP type transmission electron microscope instrument.

[0055] In the embodiment, an Avio220Max plasma emission spectrometer is used to determine the platinum content in the PtNPs@GQDs.

[0056] Example 1

[0057] Into the system dispersed with 6 grams of mesoporous SiO2, 18 mmol of citric acid triamide (4.37 grams) was added in a reaction kettle PTFE inner liner (volume 100 milliliters), 60 milliliters of deionized water was added, ultrasonic dissolution for 10 minutes, then hydrothermal reaction at 210°C for 10 hours, the obtained reaction liquid was naturally cooled to room temperature, vacuum rotary evaporation to obtain concentrated (about 10-15 milliliters) product I; to product I, dropwise add ammonium hydrogen fluoride solution, dissolve mesoporous SiO2 to a clear yellow solution, high speed centrifugation (11000r / min) for 5 minutes, remove the orange yellow large particle residues in the solution, obtain product II. Product II was vacuum rotary evaporated to obtain an orange yellow sticky material, then freeze drying to remove solvent water, finally washed with anhydrous ethanol multiple times and centrifuged, obtain 1.3 grams of yellow graphene quantum dots which are insoluble in ethanol, recorded as sample GQDs1#.

[0058] After testing, the characteristics of the graphene quantum dots were known: the powder diffraction results of sample GQDs1# are shown in Figure 1 , a graphene quantum dot characteristic diffraction peak at 2θ = 26 0 ° appears; transmission electron microscopy test shows that sample GQDs1# is graphene quantum dots of 10-15 nm stacked to form nanosheets (as shown in Figure 2 ).

[0059] Example 2

[0060] Into the system dispersed with 6 grams of mesoporous SiO2, 18 mmol of citric acid triamide (4.37 grams) was added in a reaction kettle PTFE inner liner (volume 100 milliliters), 60 milliliters of deionized water was added, ultrasonic dissolution for 10 minutes, then hydrothermal reaction at 210°C for 10 hours, the obtained reaction liquid was naturally cooled to room temperature, vacuum rotary evaporation to obtain concentrated (about 10-15 milliliters) product I; to product I, dropwise add ammonium hydrogen fluoride solution, dissolve mesoporous SiO2 to a clear yellow solution, high speed centrifugation (11000r / min) for 5 minutes, remove the orange yellow large particle residues in the solution, obtain product II. Product II was vacuum rotary evaporated to obtain an orange yellow sticky material, then freeze drying to remove solvent water, finally washed with anhydrous ethanol multiple times and centrifuged, obtain 1.3 grams of yellow graphene quantum dots which are insoluble in ethanol, recorded as sample GQDs1#.

[0061] The powder diffraction results of the obtained sample are similar to those of sample GQDs1#; the transmission electron microscopy photograph of the obtained sample is similar to that of sample GQDs1#.

[0062] Example 3

[0063] To the system dispersed with 6 grams of mesoporous SiO2, 15 mmol of citric acid and 20 mmol of dicyanediamine were added in a reaction kettle with a polytetrafluoroethylene inner liner (volume 100 ml), 60 ml of deionized water was added, ultrasonic dissolution was performed for 10 minutes, and then hydrothermal reaction was performed at 210°C for 10 hours. After the obtained reaction liquid was naturally cooled to room temperature, vacuum rotary evaporation was performed to obtain concentrated (about 10-15 ml) product I. Ammonium hydrogen fluoride solution was added dropwise to product I to dissolve the mesoporous SiO2 into a clear yellow solution. High-speed centrifugation (11000 r / min) was performed for 5 minutes to remove the orange-yellow large particle residues in the solution to obtain product II. After vacuum rotary evaporation, the orange-yellow viscous product II was obtained. After removal of solvent water through freeze-drying, the product was washed and centrifuged with anhydrous ethanol for multiple times to obtain 1.4 grams of ethanol-insoluble light yellow graphene quantum dots, which were recorded as sample GQDs3#.

[0064] The powder diffraction results of the obtained sample were similar to those of sample GQDs1#; the transmission electron microscope photos of the obtained sample were similar to those of sample GQDs1#.

[0065] Example 4 Preparation of PtNPs@GQDs chemotherapy drugs

[0066] 1.2 grams of the above sample GQDs1# precursor was weighed in a round-bottom flask and dissolved in 20 ml of deionized water. 600 mg of Na2PtCl4 (platinum content >48%) was prepared in 20 ml of deionized water, and the solution was slowly added dropwise to the GQDs aqueous solution, and the reaction was stirred. Then 20 ml of anhydrous ethanol was added. At this time, the solution was yellow with a small amount of precipitate. The reaction solution was slowly warmed to 50°C, and constant temperature reaction was performed for 0.5 hours. The solution color changed from yellow to brown, and the precipitate was completely dissolved, indicating that platinum nanoparticles were slowly formed. The reaction solution was again slowly warmed to 60°C, and constant temperature reaction was performed for 1 hour. The solution color gradually darkened, and finally a clear brown-black solution was obtained. After the reaction was stopped, the ethanol was removed by vacuum rotary evaporation to a water solution volume of about 20 ml, and the solution pH was adjusted to 7-7.5 with NaOH. The solution was centrifuged at high speed (10000 r / min) for 4 minutes to remove a small amount of black large particles in the solution. The brown-black clear liquid was vacuum freeze-dried to obtain a black solid, which was washed and centrifuged with ethanol, and then vacuum freeze-dried again to remove ethanol and water to obtain a black PtNPs@GQDs solid product of 1.5 grams.

[0067] Through transmission electron microscope test, it was seen that ultrafine platinum nanocrystals (particle size 1.5-2 nm) were dispersed in the amorphous graphene quantum dot matrix in the form of aggregates (). Figure 3 Through inductively coupled plasma atomic emission spectrometry test, it was shown that the platinum content in the solid sample was 15.85wt%.

[0068] Example 5 In vitro cancer cell proliferation inhibition test

[0069] In vitro cancer cell proliferation inhibition test of PtNPs@GQDs chemotherapy drugs: after different concentrations of PtNPs@GQDs (prepared in Example 4) were used to treat human tumor cells (3K cells) for 3 days, the absorbance value was determined by using sulfonyl rhodamine B (SRB) method, and the half inhibitory concentration IC 50 was calculated. Table 1 is the IC 50 value of PtNPs@GQDs chemotherapy drugs on different human tumor cells (calculated by platinum content, 1.2 μg Pt / mL), and PtNPs@GQDs chemotherapy drugs have high chemotherapy effect.

[0070] Table 1. In vitro cancer cell proliferation inhibition test results of PtNPs@GQDs chemotherapy drugs

[0071]

[0072] The above is only a few embodiments of the present application, and does not limit the present application in any form. Although the preferred embodiments of the present application are disclosed as above, they are not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical contents without departing from the scope of the technical solutions of the present application, and such changes or modifications are equivalent to equivalent embodiments, which are within the scope of the technical solutions.

Claims

1. A method for preparing a graphene quantum dot material, characterized in that, The method comprises the following steps: S1: a mixed solution of mesoporous SiO2 and a carbon source is subjected to a hydrothermal reaction to obtain a product I; S2: the product I is mixed with a fluoride solution to remove the SiO2 to obtain a product II; S3: the product II is subjected to purification to obtain the graphene quantum dot material; The carbon source is at least one selected from the group consisting of triammonium citrate, dihydrogen ammonium citrate, citric acid, folic acid, urea, thiourea and dicyanediamine; The fluoride is selected from ammonium hydrogen fluoride and / or hydrogen fluoride.

2. The method for preparing a graphene quantum dot material according to claim 1, wherein In step S1, the average pore size of the mesoporous SiO2 is 15-50 nm; Preferably, the mixing ratio of the mesoporous SiO2 and the carbon source is 6 g: 18-45 mmol.

3. The method for preparing a graphene quantum dot material according to claim 1, wherein In step S1, the reaction temperature of the hydrothermal reaction is 200-220°C, and the reaction time is 8-12 h.

4. The method for preparing a graphene quantum dot material according to claim 1, wherein The specific process of step S1 comprises: adding the carbon source and deionized water to a system in which the mesoporous SiO2 is dispersed to form a mixed solution, and the mixed solution is subjected to ultrasonic dispersion and dissolution and then subjected to a hydrothermal reaction; Preferably, in step S1, the reaction solution after the hydrothermal reaction is subjected to cooling and vacuum rotary evaporation to obtain the product I; Preferably, in step S2, the fluoride solution is added dropwise to the product I to remove the mesoporous SiO2; Preferably, in step S3, the product II is subjected to centrifugal separation, vacuum rotary evaporation, freeze-drying to remove solvent water, and anhydrous ethanol washing to obtain the graphene quantum dot material.

5. A graphene quantum dot material, characterized in that, The graphene quantum dot material is prepared by the preparation method of any one of claims 1-4.

6. The graphene quantum dot material of claim 5, wherein, The particle size of the graphene quantum dot material is 10-30 nm.

7. The graphene quantum dot material of claim 5 is used in tumor diagnosis, cell imaging, drug loading and release, photodynamic therapy or near-infrared photothermal therapy. Optionally, the graphene quantum dot material is used in an anti-tumor drug carrier. Optionally, the graphene quantum dot material is used as a carrier and loaded with a targeting molecule. Optionally, the targeting molecule is at least one selected from the group consisting of biotin, folic acid, RGD peptide, hyaluronic acid and TAT membrane penetrating peptide.

8. A platinum nanoparticle / graphene quantum dot composite nanomaterial, characterized in that, The platinum nanoparticles are dispersed in the amorphous graphene quantum dot matrix in the form of aggregates. The graphene quantum dot is the graphene quantum dot material of claim 5 or 6.

9. The method for preparing the platinum nanoparticle / graphene quantum dot composite nanomaterial of claim 8, comprising: The graphene quantum dot is prepared by the method of any one of claims 1-4.

10. The platinum nanoparticle / graphene quantum dot composite nanomaterial of claim 8 is used in an anti-tumor drug.

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