Near-infrared light catalytic carbon dots as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of carbon nanomaterials, and particularly relates to a near-infrared light catalytic carbon dot as well as a preparation method and application thereof. The preparation method of the near-infrared light catalytic carbon dot comprises the following steps: mixing a visible-region light-emitting carbon dot and a solvent, and carrying out solvent heat treatment, thereby obtaining the near-infrared light catalytic carbon dot, the solvent has reducibility and corrosivity at the same time. According to the invention, the strong acidity and moderate reducibility of the solvent with reducibility and corrosivity are utilized to form etching and surface functional group reconstruction on the carbon-based structure of the carbon dots, the nano-enzyme activity and photocatalytic performance of the carbon dots are enhanced, the nano-enzyme activity is high, near-infrared absorption and high-efficiency near-infrared light catalytic capability are also realized, and the application prospect is wide. Further, the nano-enzyme can be used as a nano-enzyme and near-infrared light catalytic treatment material, and efficient tumor treatment is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon nanomaterials, and particularly relates to a near-infrared light catalytic carbon dot and a preparation method and application thereof. BACKGROUND

[0002] Photocatalysts with biocompatibility and non-toxicity can effectively produce photoactive oxygen (ROS) and have attracted more and more attention in tumor phototherapy. In the cell death induced by light-induced ROS, photo-induced pyroptosis is a kind of highly immunogenic cell death (ICD), which has attracted more and more attention not only because of its strong tumor killing ability, but also because it can trigger a series of anti-cancer immune responses, has small side effects and low drug resistance, and has good application prospects in tumor phototherapy. In recent years, near-infrared (NIR) photocatalysts have attracted widespread attention due to their enhanced tissue penetration depth and higher laser power tolerance. The reported NIR-responsive molecular photosensitizers and photocatalytic nanomaterials generally exhibit the ability to generate superoxide anion (O2 - ) or singlet oxygen (O2 1 ) through an excited-state electron transfer process or an energy transfer pathway. However, the narrow band gap of the NIR-responsive photocatalysts results in a relatively high energy level of the NIR photo-generated hole, which makes it difficult for them to react with water molecules to generate hydroxyl radicals (·OH), which is the strongest ROS in oxidation. Therefore, it is of great value to develop new photocatalysts with enhanced NIR light-induced oxidation ability to generate O2 - and ·OH.

[0003] Carbon dots (CDs) are ultra-small (≤10 nm) semiconductor nanoparticles that have been recognized for their low / no toxicity, high biocompatibility, tunable luminescent properties, and multifunctional photophysical properties. Most of the reported NIR light-responsive CDs are dedicated to NIR fluorescence imaging, photothermal therapy (PTT), and rarely to NIR photocatalytic therapy (PCT). NIR-responsive photocatalytic properties have been reported only in some metal-doped carbon dot systems. In our recent study, we reported a metal-free NIR-emitting CDs with effective PCT through the introduction of oxygen-related defects under white light irradiation, and further demonstrated that white light triggered cancer cell pyroptosis to manufacture a whole cancer cell vaccine. To the best of our knowledge, there is currently no report on the NIR light-induced generation of ·OH and O2 - based on NIR-emitting metal-free CDs.

[0004] That is, the existing means for preparing carbon dots generally have the following problems: (1) the synthesized carbon dots have a generally wide band gap, and the absorption is located in the visible waveband. (2) A small number of metal-based carbon dots have near-infrared absorption, but have poor photocatalytic performance, making it difficult to achieve efficient tumor treatment.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial alternative. Specifically, the present application provides a near-infrared photocatalytic carbon dot which can produce new near-infrared absorption and has high-efficiency near-infrared photocatalytic performance and nanoscale enzyme activity.

[0007] The inventive concept of the present application: the preparation method of the near-infrared photocatalytic carbon dot of the present application is to mix visible light emitting carbon dots and a solvent with reducing and corrosive properties, and to perform solvothermal treatment to obtain the near-infrared photocatalytic carbon dot. The present application balances the excessive electron-withdrawing groups on the surface by using the reducing property of the solvent with reducing and corrosive properties, constructs a charge transfer state with near-infrared absorption, promotes the charge separation and charge transfer process, and at the same time, introduces stable defect free radicals into the carbon core by using the etching ability of the solvent with reducing and corrosive properties, so that the carbon dot itself has peroxidase (POD) activity. At the same time, the solvent with reducing and corrosive properties acts as a transition state to capture excited state electrons in the electron transfer process, reduces the recombination of electrons and holes, and further enhances the near-infrared photocatalytic effect. That is, by using the solvent with reducing and corrosive properties, the carbon-based structure of the carbon dot is etched and the surface functional groups are restructured, which enhances the nanoscale enzyme activity and photocatalytic performance of the carbon dot, and the carbon dot can be used as a near-infrared photocatalytic treatment and nanoscale enzyme material to achieve efficient tumor treatment.

[0008] Therefore, the first aspect of the present application provides a preparation method of a near-infrared photocatalytic carbon dot.

[0009] Specifically, the preparation method of the near-infrared photocatalytic carbon dot comprises the following steps:

[0010] mixing the visible light emitting carbon dots and the solvent, and performing solvothermal treatment to obtain the near-infrared photocatalytic carbon dot;

[0011] The solvent has both reducing and corrosive properties.

[0012] Preferably, the visible light emitting carbon dots are dispersed in the solvent, and the solvothermal treatment is performed to obtain the near-infrared photocatalytic carbon dot.

[0013] Specifically, the preparation method of the near-infrared photocatalytic carbon dot of the present application is simple, the raw materials are low in price, and the method is easy to mass-produce, so the method has good application prospects in the fields of biological imaging and biomedicine.

[0014] Preferably, the solvent comprises at least one of formic acid and acetaldehyde; and further preferably, the solvent is formic acid.

[0015] Preferably, the reaction temperature of the solvothermal treatment is 60-140℃; further preferably, the reaction temperature of the solvothermal treatment is 100-120℃; the reaction temperature of the solvothermal treatment according to the present application can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃ or 140℃, etc., and can also be any value between the above temperature values.

[0016] Preferably, the reaction time of the solvothermal treatment is 20-240min; further preferably, the reaction time of the solvothermal treatment is 120-150min; the reaction time of the solvothermal treatment according to the present application can be 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, 130min, 140min or 150min, etc., and can also be any value between the above adjacent time values.

[0017] Specifically, after the solvothermal treatment, the carbon dot material contains a large number of stable free radicals, new near-infrared absorption bands appear, and light emission from the near-infrared region I to region II (950-1200nm) is contributed.

[0018] Preferably, the visible light emitting carbon dots (raw carbon dots) have significantly enhanced absorption in the range of 700-1200nm after the solvothermal treatment.

[0019] Specifically, in actual operation, during the solvothermal treatment, the color of the solution becomes lighter from purple, i.e. near-infrared photocatalytic carbon dots are obtained.

[0020] Preferably, the preparation method of the near-infrared photocatalytic carbon dots further comprises dialysis purification after the solvothermal treatment; further preferably, the dialysis purification is deionized water dialysis purification, which is performed after laser treatment to separate the unreacted small molecules and carbon dots in the dialysis bag.

[0021] Preferably, the dialysis bag used for the dialysis purification has a molecular weight cut-off of 500-10000Da; further preferably, the dialysis bag used for the dialysis purification has a molecular weight cut-off of 1000-10000Da; the molecular weight cut-off of the dialysis bag used for the dialysis purification according to the present application can be 1000Da, 2000Da, 3000Da, 4000Da, 5000Da, 6000Da, 7000Da, 8000Da, 9000Da or 10000Da, etc.

[0022] Preferably, the dialysis time of the dialysis purification is 24-72h; the dialysis time of the dialysis purification of the present application can be 24h, 30h, 36h, 42h, 48h, 54h, 60h, 66h or 72h, etc.

[0023] Preferably, after the end of the dialysis purification, the solution in the dialysis bag is freeze-dried to obtain near-infrared light catalytic carbon dots; freeze-drying is adopted for drying to prevent the influence of high temperature on the product.

[0024] Preferably, the preparation method of the visible region light-emitting carbon dots comprises the following steps:

[0025] The organic compound containing hydroxyl, carbonyl and carboxyl, the nitrogen-containing organic compound and the solvent are mixed to perform a solvothermal reaction to obtain the visible region light-emitting carbon dots.

[0026] Preferably, in the actual operation process, the organic compound containing hydroxyl, carbonyl and carboxyl and the nitrogen-containing organic compound are dissolved in the solvent, and then put into a reaction kettle for high-temperature heating to perform a solvothermal reaction to obtain a dark red liquid, and the raw material carbon dots emitting red light, i.e. the visible region light-emitting carbon dots.

[0027] Specifically, the visible region light-emitting carbon dots are preferably carbon dots synthesized by high-temperature solvothermal method with more surface electron-withdrawing functional groups.

[0028] Preferably, the organic compound containing hydroxyl, carbonyl and carboxyl comprises citric acid.

[0029] Preferably, the nitrogen-containing organic compound comprises urea.

[0030] Preferably, the solvent comprises at least one of N,N-dimethylformamide, dimethyl sulfoxide and formamide.

[0031] Preferably, the mass ratio of the organic compound containing hydroxyl, carbonyl and carboxyl to the nitrogen-containing organic compound is 1:(1-8); further preferably, the mass ratio of the organic compound containing hydroxyl, carbonyl and carboxyl to the nitrogen-containing organic compound is 1:(3-4).

[0032] Preferably, in the preparation of the visible region light-emitting carbon dots, the amount of the solvent added is controlled to make the total concentration of the organic compound containing hydroxyl, carbonyl and carboxyl and the nitrogen-containing organic compound in the mixed solution be 0.05-0.5g / mL, such as 0.05g / mL, 0.1g / mL, 0.2g / mL, 0.3g / mL, 0.4g / mL or 0.5g / mL, etc., or any value between the adjacent values.

[0033] Preferably, in the process of preparing the visible region light-emitting carbon dots, the reaction temperature of the solvothermal reaction is 140-200℃, and the reaction time of the solvothermal reaction is 1-8h; further preferably, the reaction temperature of the solvothermal reaction is 180-190℃, and the reaction time of the solvothermal reaction is 4-6h; the reaction temperature and time are further optimized to improve the yield of red light-emitting carbon dots.

[0034] In the process of preparing the visible region light-emitting carbon dots, the reaction temperature of the solvothermal reaction can be 140℃, 150℃, 160℃, 170℃, 180℃, 190℃ or 200℃, etc., or any value between adjacent temperature values above; the reaction time of the solvothermal reaction can be 1h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, etc., or any value between adjacent time values above.

[0035] Specifically, in the process of preparing the visible region light-emitting carbon dots, the solvothermal reaction is carried out in a reaction kettle, preferably in a steel-lined polytetrafluoroethylene reaction kettle, and the solvothermal reaction is preferably carried out under closed conditions to prevent other factors from interfering with the reaction.

[0036] Preferably, the method for preparing the visible region light-emitting carbon dots further comprises centrifugal purification after the solvothermal reaction, and the solid precipitate is taken for drying to obtain the visible region light-emitting carbon dots.

[0037] Preferably, the centrifugal purification is centrifugal separation, which is adding an organic solvent that can promote the precipitation of carbon dots and is miscible with water to the system after the solvothermal reaction in the process of preparing the visible region light-emitting carbon dots, and then centrifugal separation is carried out to precipitate the solid.

[0038] Preferably, the organic solvent includes at least one of anhydrous ethanol and anhydrous methanol; further preferably, the organic solvent includes anhydrous ethanol, which is easy to obtain and non-toxic.

[0039] Preferably, the volume ratio of the organic solvent to the solution after the solvothermal reaction is (1-4):1; further preferably, the volume ratio of the organic solvent to the solution after the solvothermal reaction is (2-3):1; such as 1:1, 2:1, 3:1 or 4:1, etc., and it is appropriate to have an excess of organic solvent to fully separate the solid product.

[0040] Preferably, the centrifugal separation process is carried out for multiple times to increase the separation effect of the solid product; further preferably, the number of centrifugal separation is 2-4 times; such as 2 times, 3 times or 4 times.

[0041] Preferably, the centrifugal separation speed is 6000-12000 rpm, and more preferably, the centrifugal separation speed is 10000 rpm. After the centrifugal separation is completed, the obtained upper solution is removed, and the lower precipitate is freeze-dried to obtain red light-emitting carbon dots, i.e. visible light-emitting carbon dots.

[0042] Preferably, in the preparation of the visible light-emitting carbon dots, the drying is performed by freeze-drying to prevent the influence of high temperature on the product.

[0043] Preferably, the carbon dots in CN105419794A can be used as the visible light-emitting carbon dots.

[0044] The second aspect of the present application provides a near-infrared light catalytic carbon dot.

[0045] Specifically, the near-infrared light catalytic carbon dot is prepared by the preparation method of the near-infrared light catalytic carbon dot according to the first aspect of the present application.

[0046] Preferably, the near-infrared light catalytic carbon dot has at least one of the following characteristics:

[0047] 1) The near-infrared light catalytic carbon dot has a defect free radical structure;

[0048] 2) The near-infrared light catalytic carbon dot can generate a near-infrared absorption band;

[0049] 3) The near-infrared light catalytic carbon dot has photocatalytic performance and nanoscale enzyme activity.

[0050] The third aspect of the present application provides a use of the near-infrared light catalytic carbon dot according to the second aspect of the present application in the preparation of a biological fluorescence imaging reagent, a nanoscale enzyme treatment reagent, a photocatalytic treatment reagent, a tumor immunoprevention reagent or a tumor treatment reagent.

[0051] The near-infrared light catalytic carbon dot of the present application has high nanoscale enzyme activity, and also has near-infrared absorption and high near-infrared light catalytic capacity, and can be used as a nanoscale enzyme and a near-infrared light catalytic treatment material, and applied in the fields of biological fluorescence imaging, nanoscale enzyme treatment, photocatalytic treatment, tumor immunoprevention and treatment. It should be noted that the present application innovatively proposes a secondary solvent thermal treatment of formic acid for constructing a charge transfer state and a defect state, and obtains a high near-infrared light catalytic effect and is used for inducing cell pyroptosis, and further applied in the treatment and immunoprevention of mouse tumors. The aqueous solution of the carbon dot can also enter the mouse body through intravenous injection, realize long-time retention in the mouse tumor, and achieve the effect of treatment guidance. Specifically, it can be used for in-situ induction pyroptosis treatment of mouse tumors and induction of mouse immune tumors.

[0052] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0053] (1) The present application utilizes the reducing part of the solvent with reducing and corrosive property (such as formic acid) to reduce the electron-withdrawing group which dominates the surface and balance the ratio of electron-withdrawing and electron-donating groups (the electron-withdrawing groups are carbonyl, carboxyl, pyridine, etc., and the electron-donating groups are mainly hydroxyl, pyrrole, amino, etc.), construct the charge transfer state with near-infrared absorption, promote the charge separation and charge transfer process, and at the same time, utilize the acid etching ability of the solvent with reducing and corrosive property to introduce stable defect radicals into the carbon core, so that it itself has peroxidase (POD) activity, and at the same time, as a transition state in the electron transfer process, it captures the excited state electrons, reduces the recombination of electrons and holes, and generates sufficient O2 from the near-infrared light excited electrons - , generates sufficient ·OH from the holes generated by near-infrared light, and further enhances the near-infrared light catalytic effect by phonon-assisted hole transport to the lower valence band (VB) of the carbon core. That is, by utilizing the strong acidity and moderate reducing property of the solvent with reducing and corrosive property, the etching and surface functional group reconstruction of the carbon-based structure of the carbon dots are formed, the photocatalytic and nanenzyme activity thereof are enhanced, and the carbon dots with high nanenzyme activity also have near-infrared absorption and high near-infrared light catalytic ability, and can be used as near-infrared light catalytic therapy and nanenzyme materials, and realize efficient tumor treatment.

[0054] (2) The excellent superoxide anion and hydroxyl radical generation ability of the near-infrared light catalytic carbon dots of the present application can induce pyroptosis under near-infrared light, kill tumors by photocatalysis, and at the same time, can produce an anti-tumor immune response in the body, can treat and prevent the occurrence of tumors, and can be applied to the fields of biological fluorescence imaging and near-infrared light catalytic therapy.

[0055] (3) The preparation method of the near-infrared light catalytic carbon dots of the present application is simple and fast, and is convenient for large-scale production and application. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 The transmission electron microscopy and atomic force microscopy graphs of the visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2 of the present application are shown in the following figures;

[0057] Figure 2 The X-ray photoelectron spectroscopy graphs of the visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2 of the present application are shown in the following figures;

[0058] Figure 3 The Raman spectroscopy and electron spin resonance spectroscopy test result graphs of the visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2 of the present application are shown in the following figures;

[0059] Figure 4Visible light emission carbon dots of Example 1 of the present application, absorption and fluorescence change chart of near-infrared light catalytic carbon dots of Example 2 of the present application;

[0060] Figure 5 Near-infrared light catalytic performance result chart of near-infrared light catalytic carbon dots of Example 2 of the present application;

[0061] Figure 6 Fluorescence measurement chart of active oxygen species of near-infrared light catalytic carbon dots of Example 2 of the present application;

[0062] Figure 7 Toxicity test result chart of near-infrared light catalytic carbon dots of Example 2 of the present application;

[0063] Figure 8 Tumor photocatalytic treatment result chart of near-infrared light catalytic carbon dots of Example 2 of the present application on mice;

[0064] Figure 9 Pathway and immune analysis result chart of near-infrared light catalytic carbon dots of Example 2 of the present application on mice tumor photocatalytic treatment experiment;

[0065] Figure 10 After the mice treated in Test Example 8 were treated with different cancer cells again, the immune fluorescence staining of mouse lymph CD4 / CD8 and the tumor growth of mice were shown in the chart;

[0066] Figure 11 Peroxidase test result chart of near-infrared light catalytic carbon dots of Example 2 of the present application;

[0067] Figure 12 Test result chart of peroxidase performance of near-infrared light catalytic carbon dots of Example 2 of the present application on cell killing;

[0068] Figure 13 Tumor treatment ability chart of peroxidase performance of near-infrared light catalytic carbon dots of Example 2 of the present application on mice. DETAILED DESCRIPTION

[0069] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are listed for illustration. It should be pointed out that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0070] The raw materials, reagents or devices used in the following examples, if not specifically stated, can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0071] Example 1

[0072] The present embodiment provides a preparation method of visible light emission carbon dots, comprising the following steps:

[0073] Dissolve 2 g of citric acid and 4 g of urea in 30 mL of N,N-dimethylformamide (DMF), mix well, and place the liquid in a 50 mL polytetrafluoroethylene high-pressure reaction kettle. Heat the reaction at a temperature of 180 °C for 6 h. Add 60 mL of ethanol to the solution after the reaction, centrifuge at a speed of 10,000 revolutions per minute, transfer the upper solution, and take the lower precipitate. Centrifuge the lower precipitate three times, and freeze-dry the lower precipitate to obtain a dark purple solid powder, which is a red light-emitting carbon dot, i.e., a visible light-emitting carbon dot (denoted as r-CDs).

[0074] Example 2

[0075] The present example provides a preparation method of near-infrared light catalytic carbon dots, comprising the following steps:

[0076] Disperse the visible light-emitting carbon dots prepared in Example 1 in formic acid, and perform a secondary solvothermal reaction at a temperature of 110 °C for 120 min. Then, collect the solution, place it in a dialysis bag with a molecular weight cutoff of 1000 Da, and dialyze and purify it for 24 h. Replace the deionized water every 4 h. Freeze-dry the solution to obtain a black solid powder, which is a near-infrared light catalytic carbon dot (denoted as nir-CDs).

[0077] Example 3

[0078] The present example provides a preparation method of near-infrared light catalytic carbon dots, which is different from Example 2 only in that the solvent for the secondary solvothermal reaction is acetaldehyde.

[0079] Example 4

[0080] The present example provides a preparation method of near-infrared light catalytic carbon dots, which is different from Example 2 only in that the reaction temperature is 60 °C.

[0081] Example 5

[0082] The present example provides a preparation method of near-infrared light catalytic carbon dots, which is different from Example 2 only in that the reaction temperature is 65 °C.

[0083] Example 6

[0084] The present example provides a preparation method of near-infrared light catalytic carbon dots, which is different from Example 2 only in that the reaction temperature is 70 °C.

[0085] Example 7

[0086] The present example provides a preparation method of near-infrared light catalytic carbon dots, which is different from Example 2 only in that the reaction temperature is 75 °C.

[0087] Example 8

[0088] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 80 DEG C.

[0089] Embodiment 9

[0090] The embodiment provides a preparation method of near-infrared light catalytic therapeutic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 85 DEG C.

[0091] Embodiment 10

[0092] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 90 DEG C.

[0093] Embodiment 11

[0094] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 95 DEG C.

[0095] Embodiment 12

[0096] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 100 DEG C.

[0097] Embodiment 13

[0098] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 105 DEG C.

[0099] Embodiment 14

[0100] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 115 DEG C.

[0101] Embodiment 15

[0102] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 120 DEG C.

[0103] Embodiment 16

[0104] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 125 DEG C.

[0105] Embodiment 17

[0106] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the difference from the embodiment 2 is that the reaction temperature is 130 DEG C.

[0107] Example 18

[0108] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction temperature is 135℃.

[0109] Example 19

[0110] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction temperature is 140℃.

[0111] Example 20

[0112] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 20min.

[0113] Example 21

[0114] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 30min.

[0115] Example 22

[0116] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 40min.

[0117] Example 23

[0118] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 50min.

[0119] Example 24

[0120] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 60min.

[0121] Example 25

[0122] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 70min.

[0123] Example 26

[0124] This example provides a preparation method of near-infrared photocatalytic carbon dots, the only difference from Example 2 is that the reaction time is 80min.

[0125] Example 27

[0126] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the reaction time is 90 min.

[0127] Example 28

[0128] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the reaction time is 100 min.

[0129] Example 29

[0130] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the reaction time is 110 min.

[0131] Example 30

[0132] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the reaction time is 130 min.

[0133] Example 31

[0134] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the reaction time is 140 min.

[0135] Example 32

[0136] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the reaction time is 150 min.

[0137] Example 33

[0138] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the molecular weight cut-off of the dialysis bag is 2000 Da.

[0139] Example 34

[0140] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the molecular weight cut-off of the dialysis bag is 3000 Da.

[0141] Example 35

[0142] The present example provides a preparation method of near-infrared photocatalytic carbon dots, which differs from example 2 only in that the molecular weight cut-off of the dialysis bag is 4000 Da.

[0143] Example 36

[0144] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the molecular weight cut-off of the dialysis bag is 5000 Da.

[0145] Embodiment 37

[0146] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the molecular weight cut-off of the dialysis bag is 6000 Da.

[0147] Embodiment 38

[0148] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the molecular weight cut-off of the dialysis bag is 7000 Da.

[0149] Embodiment 39

[0150] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the molecular weight cut-off of the dialysis bag is 8000 Da.

[0151] Embodiment 40

[0152] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the molecular weight cut-off of the dialysis bag is 9000 Da.

[0153] Embodiment 41

[0154] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the molecular weight cut-off of the dialysis bag is 10000 Da.

[0155] Embodiment 42

[0156] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the dialysis time is 30 h.

[0157] Embodiment 43

[0158] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the dialysis time is 36 h.

[0159] Embodiment 44

[0160] The embodiment provides a preparation method of near-infrared light catalytic carbon dots, and the only difference from the embodiment 2 is that the dialysis time is 42 h.

[0161] Embodiment 45

[0162] The embodiment provides a preparation method of near-infrared photocatalytic carbon dots, and the difference from the embodiment 2 is that the dialysis time is 48 h.

[0163] Embodiment 46

[0164] The embodiment provides a preparation method of near-infrared photocatalytic carbon dots, and the difference from the embodiment 2 is that the dialysis time is 54 h.

[0165] Embodiment 47

[0166] The embodiment provides a preparation method of near-infrared photocatalytic carbon dots, and the difference from the embodiment 2 is that the dialysis time is 60 h.

[0167] Embodiment 48

[0168] The embodiment provides a preparation method of near-infrared photocatalytic carbon dots, and the difference from the embodiment 2 is that the dialysis time is 66 h.

[0169] Embodiment 49

[0170] The embodiment provides a preparation method of near-infrared photocatalytic carbon dots, and the difference from the embodiment 2 is that the dialysis time is 72 h.

[0171] Test example 1

[0172] The morphology of the visible light emitting carbon dots prepared in the embodiment 1 and the near-infrared photocatalytic carbon dots prepared in the embodiment 2 is subjected to transmission electron microscope (TEM) test and atomic force microscope (AFM) test, and the results are shown in the following table. Figure 1 The a figure in the table is a transmission electron microscope graph of the visible light emitting carbon dots in the embodiment 1, and the left graph and the right graph in the a figure are transmission electron microscope graphs with different magnifications, and the left graph is a crystal lattice magnification graph. Figure 1 The b figure in the table is a transmission electron microscope graph of the near-infrared photocatalytic carbon dots in the embodiment 2, and the left graph and the right graph in the b figure are transmission electron microscope graphs with different magnifications, and the left graph is a crystal lattice magnification graph. Figure 1 The c figure in the table is an atomic force microscope graph of the visible light emitting carbon dots in the embodiment 1. Figure 1 The d figure in the table is an atomic force microscope graph of the near-infrared photocatalytic carbon dots in the embodiment 2, Figure 1 The e figure in the table is a height statistical graph of a hatched area in the atomic force microscope graph of the visible light emitting carbon dots in the embodiment 1. Figure 1 The f figure in the table is a height statistical graph of a hatched area in the atomic force microscope graph of the near-infrared photocatalytic carbon dots in the embodiment 2. Figure 1 The f figure in the table is a height statistical graph of a hatched area in the atomic force microscope graph of the near-infrared photocatalytic carbon dots in the embodiment 2.

[0173] Figure 1The high-resolution transmission electron microscopy (HRTEM) images of Figures a and b show lattice fringes of 0.21 nm, which are attributed to the (100) crystal plane of graphene. The lattice structure of the visible region luminescent carbon dots (raw material carbon dots) in the lattice magnification of Figure a is complete, while the lattice structure of the near-infrared photocatalytic carbon dots in the lattice magnification of Figure b shows irregular dark domains. Figure 1 It can be seen from the AFM images of Figures c and d and the corresponding height statistics of Figures e and f that the heights of the visible region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2 are both between 3-5 nm.

[0174] Test Example 2

[0175] The carbon dots obtained in Examples 1 and 2 were subjected to X-ray electron spectroscopy (XPS) analysis. The results were as follows: Figure 2 The XPS high-resolution C1s, N 1s, O 1s spectra and functional group statistical analysis are shown in Figure 2. Figure 2 As shown in Figures a, b, c and d in the figure. The initial carbon dots and the carbon dots after formic acid treatment in Figures a, b, c and d represent the visible region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2, respectively.

[0176] Depend on Figure 2 It can be seen that after the secondary solvent thermal treatment with formic acid, the number of hydroxyl and pyrrolic nitrogen on the carbon dot surface increases, while the carbonyl group decreases to a certain extent, indicating that the electron-withdrawing groups on the surface are partially reduced, presumably resulting in a charge transfer state.

[0177] Test Example 3

[0178] The visible region luminescent carbon dots obtained in Example 1 and the near infrared photocatalytic carbon dots obtained in Example 2 were tested by Raman spectroscopy and electron spin resonance spectroscopy. Figure 3 As shown. Among them, Figure 3 Figure a is the Raman spectra of the visible region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2; Figure 3 Figure b is the electron spin resonance (EPR) spectrum of the visible region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2; and the initial carbon dots and the carbon dots after formic acid treatment in Figures a and b represent the visible region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2, respectively.

[0179] Depend on Figure 3 It can be seen that the near-infrared photocatalytic carbon dots obtained by formic acid solvent thermal treatment exhibit higher sp3C and more defect radical signals.

[0180] Test Example 4

[0181] The visible light emitting carbon dots obtained in Example 1 and the near-infrared light catalytic carbon dots obtained in Example 2 were optically characterized, and the changes in the absorption and fluorescence of the carbon dots before and after formic acid treatment were as shown in Figure 4 Figure 4 In the above, the a graph in the above is the UV absorption change graph of the carbon dots before and after formic acid treatment; Figure 4 The b graph in the above is the fluorescence change graph of the carbon dots before and after formic acid treatment; Figure 4 The c graph in the above is the fluorescence picture of the visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2; in addition, Figure 4 The initial carbon dots and the carbon dots after formic acid treatment in the above respectively represent the visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2.

[0182] The specific test process is as follows:

[0183] A certain amount of the visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2 were dissolved in dimethyl sulfoxide (DMSO), and the concentration was ensured to be appropriate and consistent. 2 mL of the prepared solution was taken out and placed in a UV spectrum tester, and the absorption graph of 300-1600 nm was read, and the results are as shown in the a graph in Figure 4

[0184] The visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2 were again dissolved in DMSO, and the concentration was ensured to be appropriate and consistent. 2 mL of the prepared solution was taken out and placed in a fluorescence spectrum tester, and the fluorescence graph of 900-1600 nm was read, and the results are as shown in the b graph in Figure 4

[0185] The prepared visible light emitting carbon dots of Example 1 and the near-infrared light catalytic carbon dots of Example 2 with the same concentration and the same amount of DMSO were placed under a fluorescence imaging instrument, and the 808 nm excitation light and the 1000 nm filter were selected to collect images, and the fluorescence picture is as shown in the c graph in Figure 5

[0186] From the absorption graph, it can be seen that the near-infrared light catalytic carbon dots exhibit enhanced near-infrared wide absorption band, and exhibit obvious fluorescence from the near-infrared region I to region II.

[0187] Test Example 5

[0188] The electronic behavior analysis of the near-infrared light catalytic carbon dots obtained in Example 2 under light excitation was carried out, and the specific steps were as follows:

[0189] ​​​​The near-infrared photocatalytic carbon dots in Example 2 were weighed and dissolved in DMSO, and the concentration was determined to be 100 ppm. 50 μL was taken by capillary and placed in an electron spin resonance spectrometer. A 808 nm near-infrared laser with a power of 1 W / cm2was used to irradiate it in situ for 20 min, and then dark treatment was performed for 30 min. The corresponding EPR signal was collected. 2 The near-infrared photocatalytic carbon dots in Example 2 were weighed and dissolved in DMSO, and the concentration was determined to be 100 ppm. 50 μL was taken by capillary and placed in an electron spin resonance spectrometer. A 808 nm near-infrared laser with a power of 1 W / cm2was used to irradiate it in situ for 20 min, and then dark treatment was performed for 30 min. The corresponding EPR signal was collected.

[0190] In addition, the near-infrared photocatalytic carbon dots in Example 2 were weighed and dissolved in DMSO, and the concentration was determined to be 100 ppm. 100 μL was taken in an EP tube, and 100 mM of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was added as a capture agent. The signal of superoxide anion was measured under 808 nm laser irradiation.

[0191] The carbon dots in Example 2 were weighed and dissolved in deionized water, and the concentration was determined to be 100 ppm. 100 μL was taken in an EP tube, and 100 mM of DMPO was added as a capture agent. The signal of hydroxyl radical was measured under 808 nm laser irradiation.

[0192] The carbon dots in Example 2 were weighed and dissolved in deionized water, and the concentration was determined to be 100 ppm. 100 μL was taken in an EP tube, and 100 mM of 2,2,6,6-tetramethylpiperidine (TEMP) was added as a capture agent. The signal of singlet oxygen was measured under 808 nm laser irradiation.

[0193] 100 μL of water or dimethyl sulfoxide was weighed in an EP tube, and 100 mM of DMPO was added as a capture agent. It was tested under 808 nm laser irradiation.

[0194] The results of the analysis of the electronic behavior of the near-infrared photocatalytic carbon dots in Example 2 are shown in FIG. 1, wherein, Figure 5 FIGS. 1a and 1b of FIG. 1 are electron paramagnetic resonance (EPR) spectra of the near-infrared photocatalytic carbon dots in Example 2 after 808 nm laser irradiation and after stopping the irradiation, respectively; Figure 5 FIG. 1c of FIG. 1 is an EPR spectrum of active oxygen captured by different capture agents. Figure 5 FIGS. 1a and 1b of FIG. 1 show that the near-infrared photocatalytic carbon dots in Example 2 still have relatively stable defect free radical signals after laser extinction. FIG. 1c shows that through the capture analysis of active oxygen species generated under near-infrared excitation, it is shown that the near-infrared photocatalytic carbon dots have high superoxide anion and hydroxyl radical production capacity.

[0195] Figure 5 Test Example 6 Figure 6

[0196] Test Example 6

[0197] The near-infrared photocatalytic performance of the near-infrared photocatalytic carbon dots obtained in Example 2 was analyzed by fluorescence analysis, and the specific steps were as follows:

[0198] Equal amounts of the visible-light-emitting carbon dots from Example 1 and the near-infrared photocatalytic carbon dots from Example 2 were weighed and dissolved in water. The carbon dots were then added to 2 mL of PBS to a final concentration of 10 ppm. 2',7'-dichlorodihydrofluorescein (DCFH) was used as a probe for total reactive oxygen species production, and the results were measured under 808 nm laser irradiation.

[0199] Equal amounts of the visible-region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2 were weighed and dissolved in water. The carbon dots were then added to 2 mL of PBS to a final concentration of 10 ppm. 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) was used as a probe for total reactive oxygen species production, and the results were tested under 808 nm laser irradiation.

[0200] Equal amounts of the visible-region luminescent carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2 were weighed and dissolved in water. The carbon dots were then added to 2 mL of PBS to a final concentration of 10 ppm. Reduced nicotinamide adenine dinucleotide (NADH) was used as a probe for total reactive oxygen species production and tested under 808 nm laser irradiation.

[0201] Example 2 Fluorescence measurement of active oxygen species of near-infrared photocatalytic carbon dots Figure 6 As shown, Figure 6 Figures a, b, and c are fluorescence measurements of reactive oxygen species using different probes.

[0202] Depend on Figure 7 It can be seen that the near-infrared photocatalytic carbon dots in Example 2 exhibited strong ability to generate total active oxygen and oxidize NADH, and no singlet oxygen was generated, indicating that excited state electrons were mainly annihilated through electron transfer.

[0203] Test Example 7

[0204] The toxicity test of the near-infrared photocatalytic carbon dots obtained in Example 2 was carried out, and the specific steps were as follows: three different types of cancer cells (EMT6 cells, ID8 cells, and B16 cells) were laid, and different concentrations (0, 62.5, 125, 250, and 500 μg / mL) of the near-infrared photocatalytic carbon dots of Example 2 were added respectively. After 48 hours of dark field treatment, the corresponding absorption was measured to confirm cell viability;

[0205] EMT6 cells were plated, and different concentrations (0, 62.5, 125, 250, 500 μg / mL) of near-infrared photocatalytic carbon dots of Example 2 were added, and the photocatalytic activity was measured at 1 W / cm 2The corresponding absorption was measured after 48 h to confirm the cell viability.

[0206] In addition, EMT6 cells were laid, and divided into two groups, 500 μg / mL near-infrared photocatalytic carbon dots group and 500 μg / mL near-infrared photocatalytic carbon dots plus 1 W / cm 2 The 808 nm near-infrared laser irradiation group, and then the cell state was observed by microscope.

[0207] The toxicity test results of the near-infrared photocatalytic carbon dots of Example 2 are shown in Figure 7 . Among them, Figure 7 a figure in the figure is a graph of in vitro toxicity and phototoxicity results; Figure 7 b figure in the figure is a graph of induced pyroptosis cells, and the left figure in b figure is a graph of cell state after treatment of the near-infrared photocatalytic carbon dots of Example 2, the middle figure in b figure is a graph of cell state after treatment of the near-infrared photocatalytic carbon dots of Example 2 and laser irradiation, and the scale is the same as the left figure, and the right figure in b figure is an enlarged view of the red box in the middle figure.

[0208] Figure 7 As shown in a figure in the figure, only 0.125 mg / mL shows obvious phototoxicity, Figure 8 The cell imaging of b figure in the figure shows that it well induces cell pyroptosis.

[0209] Test Example 8

[0210] The near-infrared photocatalytic carbon dots prepared in Example 2 were subjected to mouse tumor photocatalytic treatment experiment, and the specific steps included:

[0211] The mouse tail vein was injected with 100 μL of 500 μg / mL carbon dots, and irradiated with 1 W / cm 2 of 808 nm near-infrared laser for 10 min, recorded as tail vein injection + laser group: G4; The control test was respectively injected with PBS without treatment (control group: G1), 1 W / cm 2 of 808 nm near-infrared laser for 10 min (laser group: G2), and 100 μL of 500 μg / mL carbon dots were injected into the tail vein without light (tail vein injection group: G3); Before and after treatment, the mouse tumor was subjected to hematoxylin-eosin staining (H&E) and proliferation activity detection (Ki67) analysis, the tumor volume and mouse body weight were observed every two days, and the tumor was dissected after 16 days to compare the tumor size of each group.

[0212] The results of the near-infrared photocatalytic carbon dots of Example 2 on mouse tumor photocatalytic treatment are shown in Figure 8 . Among them, Figure 8Figure a shows the H&E and Ki67 immunohistochemistry results of near-infrared photocatalytic carbon dots used to treat mouse tumors and those without treatment, and the scale in the immunohistochemistry results of G1 is the same as that of G4; Figure 8 Figure b shows the tumor treatment effects of mice in different groups; Figure 8 Figure c shows the tumor growth of mice in different groups after 16 days of treatment.

[0213] Depend on Figure 8 As can be seen in Figure a, the structure of mouse tumor cells was significantly destroyed and their proliferation ability was significantly inhibited after photocatalytic treatment; Figure 9 As can be seen from Figures b and c, infrared photocatalytic carbon dots with photocatalytic properties are extremely effective in photocatalytic treatment of tumors.

[0214] Test Example 9

[0215] The pathway and immune analysis of the near-infrared photocatalytic carbon dots prepared in Example 2 were performed in a mouse tumor photocatalytic treatment experiment. The specific steps included:

[0216] 100 μL of 500 μg / mL carbon dots were injected into the tail vein of mice and the concentration of carbon dots was 1 W / cm 2 The control group consisted of the following groups: PBS injection without treatment (control group: G1), 1W / cm 2 The mice were irradiated with an 808 nm near-infrared laser for 10 min (laser group: G2) and injected with 100 μL of 500 μg / mL carbon dots through the tail vein without irradiation (tail vein injection group: G3). Caspase-3 (c-cas-3) and gasdermin E (GSDME) were analyzed in the mouse tumors before and after treatment, and CD4 / CD8 immunofluorescence staining was performed on the lymph nodes.

[0217] Example 2 Pathway and immunoassay results of near-infrared photocatalytic carbon dots photocatalytic treatment of mouse tumors Figure 9 As shown. Among them, Figure 9 Figure a shows the c-cas-3 / N-GSDME analysis results of mouse tumors after photocatalytic treatment with near-infrared photocatalytic carbon dots. The scales of the figures in Figure a are the same. Figure 9 Figure b shows the results of CD4 / CD8 immunofluorescence staining of mouse lymph nodes after photocatalytic treatment of mice with near-infrared photocatalytic carbon dots. The scales of the figures in Figure b are the same.

[0218] Depend on Figure 10It can be seen that the c-cas-3 and N-GSDME signals in the tumor sections of the experimental group are obviously stronger, indicating that it mainly induces pyroptosis through the c-cas-3 / N-GSDME pathway, and the staining of CD4 / CD8 also proves that the experimental group triggers a strong immune response.

[0219] Test Example 10

[0220] The mice treated in Test Example 8 were re-challenged and the relevant parameters were analyzed, and the specific steps included:

[0221] The mice that had been treated (tail vein injection + laser group in Test Example 8: G4) were inoculated with 4T1 and EMT6 cells, respectively, and the tumor volume and mouse weight were observed every two days, and the tumor size was compared after 36 days of dissection, and CD4 / CD8 immunofluorescence staining analysis was performed on the lymph.

[0222] After treating the treated mice with different cancer cells, the immunofluorescence staining of mouse lymph CD4 / CD8 and the tumor growth of mice are as shown in Figure 10 , wherein, Figure 10 a graph in is a graph of the immunofluorescence staining results of mouse lymph CD4 / CD8, and the scales of each graph in a graph are the same; Figure 10 b graph in is a graph of the tumor treatment effect of mice; Figure 10 c graph in is a graph of the tumor growth of mice after 36 days of treatment.

[0223] As can be seen from Figure 11 , the mice implanted with the same cancer cells (EMT6) also have a strong immune response, and the tumor growth curve also shows that they have good immunity to the same tumor.

[0224] Test Example 11

[0225] This test example mainly aims to test the peroxidase (POD) of the near-infrared light catalytic carbon dots of Example 2, and the specific steps include:

[0226] Take the near-infrared light catalytic carbon dots of Example 2, dissolve in deionized water, and determine the concentration to be 100 ppm, take out 100 μL in an EP tube, add 100 mM of DMPO as a capture agent, and add 1 μL of hydrogen peroxide to measure the signal of hydroxyl radicals;

[0227] Take the visible region luminescent carbon dots of Example 1, dissolve in deionized water, and determine the concentration to be 100 ppm, take out 100 μL in an EP tube, add 100 mM of DMPO as a capture agent, and add 1 μL of hydrogen peroxide to measure the signal of hydroxyl radicals;

[0228] In addition, 1 μL of hydrogen peroxide and 100 mM of DMPO capture agent were used as a control group.

[0229] The test results of the near-infrared photocatalytic carbon dot peroxidase of Example 2 are shown in Figure 11 Table 2. Among them, the initial carbon dots and the carbon dots after formic acid treatment represent the visible light emitting carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2, respectively.

[0230] As can be seen from Table 2, the near-infrared photocatalytic carbon dots also have good nanocatalytic performance. Figure 12

[0231] Test Example 12

[0232] The main purpose of this test example is to test the peroxidase (POD) performance of the near-infrared photocatalytic carbon dots of Example 2 on cell killing, and the specific steps include:

[0233] Two groups of EMT6 cells were laid, and different concentrations (0, 50, 100, 200, 500, 1000 μg / mL) of the visible light emitting carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2 were added, respectively. After 48 h of incubation, the corresponding absorption was measured to confirm the cell viability.

[0234] The test results of the peroxidase performance of the near-infrared photocatalytic carbon dots of Example 2 on cell killing are shown in Figure 12 Table 3. Among them, the initial carbon dots and the carbon dots after formic acid treatment represent the visible light emitting carbon dots of Example 1 and the near-infrared photocatalytic carbon dots of Example 2, respectively.

[0235] As can be seen from Table 3, only 100 μg / mL of the near-infrared photocatalytic carbon dots has shown obvious half lethal rate, indicating that the near-infrared photocatalytic carbon dots of Example 2 have good nanocatalytic activity. Figure 13 Test Example 13

[0236] The main purpose of this test example is to test the peroxidase (POD) performance of the near-infrared photocatalytic carbon dots of Example 2 on the treatment ability of mouse tumors, and the specific steps include:

[0237] The near-infrared photocatalytic carbon dots of Example 2 were injected into the intratumoral and tail vein of the mice, and the intratumoral and tail vein of the mice were injected with 100 μL of 500 μg / mL of the near-infrared photocatalytic carbon dots of Example 2, once every other day, for three times. The control group was untreated mice. The tumor size of the mice was recorded every two days, and the tumor was removed on the 22nd day for photography and evidence.

[0238] The treatment ability of the peroxidase performance of the near-infrared photocatalytic carbon dots of Example 2 on mouse tumors is shown in

[0239] Figure a in Table 4 is a diagram of the tumor size of the mice after treatment in different groups. Figure 13 Figure 13 Figure 13 ​​​Figure b in the figure is a mouse tumor photo after treatment in different groups.

[0240] By ​ It can be known that the mouse intratumoral injection, tail vein injection, and combination of intratumoral and tail vein injection all have good tumor treatment ability, especially the combination of intratumoral and tail vein injection, after three injection treatments, the mouse tumor disappears, which shows that the near-infrared light catalytic carbon dots with good peroxidase performance of the application can realize efficient tumor treatment.

[0241] In addition, the near-infrared light catalytic carbon dots prepared in embodiments 3-49 of the application can achieve the same technical effects as the near-infrared light catalytic carbon dots of embodiment 2.

[0242] In summary, by using formic acid and other solvents for secondary solvothermal treatment, the application can partially reduce the surface-dominant electron-withdrawing groups and balance the ratio of electron-withdrawing and electron-donating groups, enhancing the charge transfer state. At the same time, the carbon core can also be etched, resulting in lattice defects, forming a large number of vacancies and stable free radicals. The combined effect of charge transfer state and defect state can further promote near-infrared light-induced charge separation, while inhibiting the recombination of excited electrons and holes, thereby generating sufficient O2 - from near-infrared light excited electrons, generating sufficient ·OH from near-infrared light generated holes, and transporting to the lower valence band (VB) of the carbon core through phonon-assisted holes. In addition, the strong ROS generated by near-infrared light can effectively induce pyroptosis of cancer cells through activation of the caspase-3 / gasdermin E (GSDME) pathway and show good anti-tumor immune effect to prevent tumor recurrence in mouse models, and has good application prospects in the fields of bioluminescence imaging, near-infrared light catalytic treatment, and tumor immune prevention.

[0243] The above examples are only used to illustrate the technical solutions of the application and not to limit the scope of protection of the application. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the application.

Claims

1. A method for preparing near-infrared photocatalytic carbon dots, characterized in that: The following steps are involved: Mixing visible region luminescent carbon dots and a solvent, and performing a solvent thermal treatment to obtain the near-infrared photocatalytic carbon dots; The solvent is both reducing and corrosive.

2. The preparation method according to claim 1, characterized in that The solvent includes at least one of formic acid and acetaldehyde.

3. The preparation method according to claim 1, characterized in that The reaction temperature of the solvent thermal treatment is 60-140° C.; and / or the reaction time of the solvent thermal treatment is 20-240 min.

4. The preparation method according to claim 1, characterized in that The preparation method further comprises performing dialysis purification after the solvent thermal treatment; Preferably, the molecular weight cut-off of the dialysis bag used for the dialysis purification is 500-10000Da; and the dialysis time for the dialysis purification is 24-72h.

5. The preparation method according to claim 1, characterized in that The method for preparing the visible region luminescent carbon dots comprises the following steps: An organic compound containing hydroxyl, carbonyl and carboxyl groups, an organic compound containing nitrogen and a solvent are mixed and subjected to a solvent thermal reaction to obtain the visible region luminescent carbon dots.

6. The preparation method according to claim 5, characterized in that The organic compound containing hydroxyl, carbonyl and carboxyl groups includes citric acid; and / or the nitrogen-containing organic compound includes urea; and / or the solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide and formamide.

7. The preparation method according to claim 5, characterized in that The mass ratio of the organic compound containing hydroxyl, carbonyl and carboxyl groups to the nitrogen-containing organic compound is 1:(1-8); and / or the reaction temperature of the solvent thermal reaction is 140-200° C., and the reaction time of the solvent thermal reaction is 1-8 hours.

8. The preparation method according to claim 5, characterized in that The method for preparing the visible region luminescent carbon dots further comprises performing centrifugal purification after the solvothermal reaction, and drying the solid precipitate to obtain the visible region luminescent carbon dots; Preferably, the drying is performed by freeze drying.

9. A near-infrared photocatalytic carbon dot, characterized in that The near-infrared photocatalytic carbon dots are prepared by the preparation method according to any one of claims 1 to 8; Preferably, the near-infrared photocatalytic carbon dots have at least one of the following characteristics: 1) The near-infrared photocatalytic carbon dots have a defective free radical structure; 2) The near-infrared photocatalytic carbon dots can produce near-infrared absorption bands; 3) The near-infrared photocatalytic carbon dots have photocatalytic properties and nanozyme activity.

10. Use of the near-infrared photocatalytic carbon dots according to claim 9 in the preparation of bioluminescent imaging agents, nanozyme therapeutic agents, photocatalytic therapeutic agents, tumor immunoprevention agents or tumor therapeutic agents.

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