Black phosphorus nanosheet drug delivery system for enhancing blood-brain barrier permeability of pterostilbene and preparation method of black phosphorus nanosheet drug delivery system

Abstract

The invention provides a black phosphorus nanosheet drug delivery system for enhancing blood-brain barrier permeability of pterostilbene and a preparation method of the black phosphorus nanosheet drug delivery system. The invention provides the black phosphorus nanosheet drug delivery system for enhancing the blood-brain barrier permeability of the pterostilbene and the preparation method of the black phosphorus nanosheet drug delivery system. The black phosphorus nanosheet drug delivery system provided by the invention has good drug loading capacity and photothermal effect, and has good drug release capacity under acidic conditions and near-infrared illumination conditions. The black phosphorus nanosheet drug delivery system disclosed by the invention is modified by polydopamine, so that the stability of the black phosphorus nanosheet is improved, and the black phosphorus nanosheet drug delivery system has good stability. The black phosphorus nanosheet drug delivery system disclosed by the invention can improve the blood brain barrier permeability of the pterostilbene and enhance the treatment effect of the pterostilbene in the brain under the condition of near-infrared illumination. The black phosphorus nanosheet drug delivery system disclosed by the invention does not generate a hemolysis effect under a treatment concentration, and has good biocompatibility and low toxicity.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedical materials, and specifically relates to a black phosphorus nanosheet drug delivery system for enhancing the permeability of red sandalwood blood-brain barrier and a preparation method thereof. Background Art

[0002] Stroke is a neurological deficit syndrome caused by acute vascular or blood abnormalities leading to cerebral blood circulation disorders. It is characterized by high morbidity, high recurrence rate, high disability rate and high mortality rate. Stroke is one of the leading causes of death and long-term disability worldwide, and the third leading cause of death in Chinese people, second only to malignant tumors and heart disease. Clinically, stroke is divided into ischemic stroke (IS) and hemorrhagic stroke (HS), of which IS accounts for as much as 70% and is the main type of stroke, mainly caused by cerebral artery embolism. Although with the advancement of medical science, the survival rate of stroke has exceeded 50%, IS is still the main cause of physical damage, leading to neurological disorders and impairing physical ability and mental functions, including cognition, learning, memory, etc.

[0003] Only a limited number of drugs have made real progress in the treatment of IS. Intravenous injection of recombinant tissue plasminogen activator (t-PA) or intravascular therapy is currently the only available treatment for acute ischemic stroke, but its narrow therapeutic window and side effects limit its clinical application, and most drugs fail to achieve significant therapeutic effects due to their inability to effectively cross the blood-brain barrier (BBB). Nanocarriers have been studied as drug delivery vehicles for the treatment of the central nervous system. Nanomaterials have many advantages, such as biocompatibility, non-toxicity, the ability to carry multiple payload therapeutic drugs, protection of therapeutic drugs from degradation in the body, and long-term controlled drug release and crossing the blood-brain barrier.

[0004] Among the emerging two-dimensional nanomaterials, black phosphorus (BP) is used in various biomedical applications, including photothermal therapy, drug delivery, biosensing, and bioimaging. In the biomedical field, the honeycomb pleated structure can effectively increase the drug loading of drugs, biomolecules, and imaging agents, and this BP is easily degraded in the physiological environment and will not cause toxicity to the body. After loading drugs, targeting molecules, and fluorescent molecules, BP nanosheets achieve targeted detection-therapy combined performance and light-controlled drug release capabilities.

[0005] BP has excellent biocompatibility and biodegradability, and can generate a large number of oxygen free radicals and heat under the irradiation of near-infrared lasers, which makes black phosphorus show unlimited potential in photothermal therapy and photodynamic therapy, and black phosphorus nanosheets can enhance the permeability of the blood-brain barrier after near-infrared (NIR) irradiation through photothermal effect. Therefore, BP can be used as a good nanomaterial for the treatment of neurological diseases.

[0006] Pterostilbene (Pte) is a natural dimethylated analog of resveratrol, mainly found in blueberries and grapes. Pte is similar to resveratrol in terms of its beneficial effects on the central nervous system and cardiovascular diseases, and has been shown to have antioxidant, anti-apoptotic, anti-cancer and anti-inflammatory activities in vivo. Pte has a low molecular weight and strong lipophilicity, so it can easily pass through the blood-brain barrier, has greater bioavailability, and is more biologically active than resveratrol. In terms of safety, Pte has almost no toxic side effects and is classified as low risk. Pte has poor water solubility (about 21 μg / mL), and other approaches must be used to improve the solubility of Pte. Therefore, it is hoped that an efficient dosage form can be prepared to improve the solubility of pterostilbene to enhance its ability to resist ischemic stroke.

[0007] BP has poor stability. When exposed to air or placed in aqueous solution in the presence of light, BP will degrade to form non-toxic PxOy oxide, which will further generate phosphoric acid with water in the environment, thus losing its properties and limiting its scope of application. Therefore, some methods need to be taken to protect its special functions. For example, the surface of BP can be coated to isolate it from the air to prevent it from oxidation. Mussel-inspired polydopamine (PDA) combines biocompatibility and unique adhesion properties. It has the potential to develop into a simple, fast and economical nanoparticle platform using a simple preparation method based on self-polymerization. PDA has good pH responsiveness and can remain stable under neutral pH conditions (such as blood, tissue fluid, etc.), but degrades under acidic microenvironment conditions, thereby releasing drugs and achieving therapeutic effects. Therefore, PDA can be used as a material for encapsulating black phosphorus, which can successfully enhance the stability of black phosphorus and modify more functional groups.

[0008] In summary, the present invention designs a method of preparing low-layer and uniformly sized black phosphorus nanosheets by liquid phase exfoliation, so that they have a certain blood-brain barrier permeability, and at the same time improves their brain targeting ability after PEG modification, connects pterostilbene to wrap PDA on its surface, and constructs a complete black phosphorus nanosheet drug delivery system. The mouse middle cerebral artery embolism reperfusion model was used to explore the drug content of pterostilbene in the brain of mice after cerebral ischemia / reperfusion under different dosage forms, providing new ideas for the clinical application of pterostilbene. Summary of the invention

[0009] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for preparing a black phosphorus nanosheet drug delivery system for enhancing the blood-brain barrier permeability of red stilbene. The black phosphorus nanosheet drug delivery system of the present invention has good photothermal effect, stability, blood-brain barrier permeability and low toxicity, and has good application prospects in the treatment of nervous system diseases and drug delivery.

[0010] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a black phosphorus nanosheet drug delivery system for enhancing the blood-brain barrier permeability of pterostilbene, wherein the black phosphorus nanosheet drug delivery system is a sheet-shaped layered structure, the black phosphorus nanosheets are modified with polyethylene glycol (PEG) to form BP-PEG, the model drug pterostilbene (Pte) is combined with the black phosphorus nanosheets by electrostatic adsorption, and polydopamine (PDA) is wrapped on the surface of the black phosphorus nanosheets, that is, the black phosphorus nanosheet drug delivery system (BP-Pte@PDA).

[0011] In some embodiments of the present invention, the mass ratio of the black phosphorus nanosheets to the polyethylene glycol is 1:10.

[0012] In some preferred embodiments of the present invention, the mass ratio of the BP-PEG to the Pte is 1:6.

[0013] In some more preferred embodiments of the present invention, the mass ratio of the BP-Pte to the DA is 1:7.5.

[0014] In some more preferred embodiments of the present invention, the average size of the black phosphorus nanosheets is 100-200 nm.

[0015] In some more preferred embodiments of the present invention, the particle size of the black phosphorus nanosheet-loaded pterostilbene composite material is 200-250 nm.

[0016] In some more preferred embodiments of the present invention, the particle size of the polydopamine-modified black phosphorus nanosheet drug delivery system is 250 to 300 nm.

[0017] The present invention proposes a method for preparing a black phosphorus nanosheet drug delivery system for enhancing the blood-brain barrier permeability of red sandalwood, comprising the following steps:

[0018] Take an appropriate amount of pterostilbene and dissolve it with an equal volume of solvent. Centrifuge the suspension of black phosphorus nanosheets modified with polyethylene glycol at high speed and low temperature for 30 minutes, remove the supernatant, add the pterostilbene solution, shake at low temperature in the dark, and centrifuge at high speed and low temperature to obtain a precipitate. Take an appropriate amount of dopamine hydrochloride and dissolve it in an appropriate amount of pure water, add it to the above precipitate, adjust the pH to 8.5, shake at low temperature in the dark, centrifuge at high speed and low temperature, add ultrapure water to the precipitate and resuspend it, and obtain a solution of the polydopamine-modified black phosphorus nanosheet drug delivery system (BP-Pte@PDA).

[0019] In some embodiments of the present invention, the solvent is selected from at least one of PEG400, ethanol, and DMSO.

[0020] In some preferred embodiments of the present invention, the high-speed low-temperature centrifugation conditions are 12000 rpm, 4°C, and the light-proof shaking time is 48 hours.

[0021] In some preferred embodiments of the present invention, the method for preparing the black phosphorus nanosheets comprises: weighing black phosphorus powder and dispersing it in an organic solvent, placing it in a mortar, grinding it at low temperature in the dark, transferring all the ground suspension to an EP tube, and adding an ice organic solvent. The obtained black phosphorus suspension is ultrasonicated in an ice water bath in an ultrasonic machine in the dark, and the water is continuously changed during the period to ensure the low temperature state, and then the ultrasound is continued in a cell disruptor. After completion, the suspension is taken out and allowed to stand at 4°C overnight. Take the upper layer of the suspension after standing, centrifuge it at low speed and low temperature for 5 minutes, take the upper liquid, and then replace NMP with an equal volume of ultrapure water after two high-speed low-temperature centrifugations to obtain a black phosphorus nanosheet suspension solution.

[0022] In some preferred embodiments of the present invention, the organic solvent is selected from any one of N-methylpyrrolidone (NMP), dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0023] In some preferred embodiments of the present invention, the grinding time is 1 hour, the ultrasonic power is 500 W, the ice-water bath ultrasonic time is 6 hours, and the cell disruptor ultrasonic time is 1 hour.

[0024] In some preferred embodiments of the present invention, the low-speed low-temperature centrifugation conditions are 2000 rpm and 4°C, and the high-speed low-temperature centrifugation conditions are 15000 rpm and 4°C.

[0025] In some more preferred embodiments of the present invention, the method for preparing black phosphorus nanosheets modified with polyethylene glycol includes: taking a black phosphorus nanosheet (BP) suspension, adding polyethylene glycol (PEG-NH2), ultrasonicating, vortex mixing, shaking in the dark under low temperature conditions, centrifuging at high speed under low temperature conditions for 30 minutes, and removing the supernatant to obtain the PEG-modified black phosphorus nanosheets (BP-PEG).

[0026] In some more preferred embodiments of the present invention, the molecular weight of the polyethylene glycol (PEG-NH2) is 3400.

[0027] In some more preferred embodiments of the present invention, the ultrasonic power is 500 W and the ultrasonic time is 30 min.

[0028] In some more preferred embodiments of the present invention, the light-proof shaking time is 12 h, and the high-speed low-temperature centrifugation conditions are 12000 rpm and 4°C.

[0029] The invention provides a stable preparation capable of penetrating the blood-brain barrier, comprising the polydopamine-modified black phosphorus nanosheet drug delivery system.

[0030] In the present invention, the black phosphorus nanosheet drug delivery system can improve its ability to penetrate the blood-brain barrier under near-infrared light conditions.

[0031] The present invention proposes a black phosphorus nanosheet drug delivery system for enhancing the blood-brain barrier permeability of red stilbene, and the black phosphorus nanosheet drug delivery system is the above-mentioned black phosphorus nanosheet drug delivery system.

[0032] The beneficial effects of the present invention are:

[0033] The present invention utilizes the principle of electrostatic adsorption to functionalize and modify Pte and PEG molecules onto the surface of negatively charged black phosphorus nanosheets, which are then surface-modified by PDA. By irradiating the black phosphorus nanosheets with near-infrared lasers, the black phosphorus nanosheet drug delivery system can penetrate the blood-brain barrier and control the release of drugs, thereby improving the therapeutic level of drugs in the brain, reducing the risk of medication, and having a therapeutic effect superior to direct administration.

[0034] The black phosphorus nanosheet drug delivery system of the present invention has good stability due to the modification of polydopamine.

[0035] The black phosphorus nanosheet drug delivery system of the present invention may be used as a drug carrier for the treatment of other diseases, thereby being used for targeted treatment of target diseases, becoming a new strategy for the treatment of other nervous system diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0037] Figure 1 The transmission electron microscopy images of the black phosphorus nanosheets in the embodiment of the present invention (A), the transmission electron microscopy image of the black phosphorus nanosheet-loaded pterostilbene composite material (B), and the transmission electron microscopy image of the black phosphorus nanosheet composite material modified with polydopamine (C).

[0038] Figure 2The drug loading rate (A) and full-wavelength UV spectrum (B) of black phosphorus nanosheets and drugs of different masses in the embodiment of the present invention are shown.

[0039] Figure 3 1 and 2 are the particle size distribution diagram (A) and Zeta potential distribution diagram (B) of the black phosphorus nanosheets, the black phosphorus nanosheet-loaded pterostilbene composite material, and the polydopamine-modified black phosphorus nanosheet composite material in the embodiments of the present invention.

[0040] Figure 4 The temperature change diagram of PBS, black phosphorus nanosheet solution and polydopamine-modified black phosphorus nanosheet drug delivery system solution under near-infrared laser irradiation in the embodiment of the present invention (A), the temperature change diagram of the black phosphorus nanosheet drug delivery system solution modified by polydopamine under near-infrared laser irradiation of different powers (B), the temperature change diagram of the black phosphorus nanosheet drug delivery system solution modified by polydopamine at different concentrations under near-infrared laser irradiation (C), and the temperature change diagram of the black phosphorus nanosheet drug delivery system solution modified by polydopamine after 5 cycles of near-infrared light switching (D).

[0041] Figure 5 This is a UV full-wavelength variation graph of the stability changes of black phosphorus nanosheets, black phosphorus nanosheet-loaded pterostilbene composite materials, and polydopamine-modified black phosphorus nanosheet drug delivery system solutions in the embodiments of the present invention at 1, 4, and 7 days.

[0042] Figure 6 This is a graph showing the results of a hemolysis experiment of a black phosphorus nanosheet drug delivery system modified with polydopamine at different concentrations in an embodiment of the present invention.

[0043] Figure 7 UPLC measurements of drug content in the blood (A) and brain (B) of mice in the pterostilbene administration group and the polydopamine-modified black phosphorus nanosheet drug delivery system administration group in the examples of the present invention. Figure 8 This is a graph of the pharmacokinetic parameters of mouse plasma measured by UPLC in the pterostilbene administration group and the polydopamine-modified black phosphorus nanosheet drug delivery system administration group in an example of the present invention. Fig. 9 This is a graph of the pharmacokinetic parameters of mouse brain tissue measured by UPLC in the pterostilbene administration group and the polydopamine-modified black phosphorus nanosheet drug delivery system administration group in the examples of the present invention. DETAILED DESCRIPTION

[0044] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0045] The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0046] In the embodiment of the present invention, the preparation method of the polydopamine-modified black phosphorus nanosheet drug delivery system is as follows:

[0047] S1: Preparation of black phosphorus nanosheets (BP):

[0048] BP was prepared by liquid phase exfoliation. 0.1 g of BP was thoroughly ground in a mortar, and then kept at a constant temperature of 10 ° C for 48 h using an ultrasonic cleaner (power: 500w) under the action of a circulating water cooler, and then rotated at 2000 rpm / min for 5 min. The supernatant was collected, rotated at 15000 rpm for another 5 min, the precipitate was taken, and 1 ml of NMP was added. The suspension of black phosphorus nanosheets was obtained and stored in a 4 ° C refrigerator.

[0049] S2: Preparation of black phosphorus nanosheet-loaded pterostilbene composites (BP-Pte)

[0050] Take 5 mL of the black phosphorus nanosheet (BP) suspension that has been ultrasonicated for 6 hours, weigh PEG-NH2 (MW: 3400) 10 times the weight of black phosphorus, add it to the suspension, ultrasonicate at 500W for 30 minutes, vortex for 5 minutes, shake at 300rpm, 4℃ on a shaker in the dark for 12 hours, centrifuge at 12000rpm, 4℃ for 30 minutes, and remove the supernatant. Take 2, 4, 6, 8, and 10 times the weight of black phosphorus, dissolve it in an equal volume of anhydrous ethanol, add the pterostilbene solution to the BP-PEG precipitate, shake at 300rpm, 4℃ on a shaker in the dark for 24 hours, centrifuge at 12000rpm, 4℃ for 20 minutes, add ultrapure water to the precipitate and resuspend it to obtain the black phosphorus-loaded pterostilbene (BP-Pte) solution.

[0051] S3: Preparation of polydopamine-modified black phosphorus nanosheet drug delivery system

[0052] The pH of the BP-Pte solution was adjusted to 8.5, and dopamine hydrochloride was added at 7.5 times the weight of black phosphorus. The solution was shaken at room temperature in the dark for 12 hours, and the sample was centrifuged at 12000 rpm, 4°C, and 20 minutes to remove the supernatant. The sample was washed twice with PBS under the same centrifugation conditions, and the precipitate was taken and resuspended in ultrapure water to obtain the polydopamine-modified black phosphorus nanosheet drug delivery system (BP-Pte@PDA) solution.

[0053] Test Example 1

[0054] This test example analyzes the structural characteristics and performance of the intermediates and products in the preparation process of the examples.

[0055] The black phosphorus nanosheets, black phosphorus nanosheets loaded with pterostilbene composites (BP-Pte), and black phosphorus nanosheets modified with polydopamine (BP-Pte@PDA) were observed by electron microscopy. Figure 1 shown.

[0056] from Figure 1 It can be seen from the figure that the black phosphorus crystals have a low-layered sheet structure and good dispersion. After drug loading, it is obvious that the drug is successfully loaded. Polydopamine evenly wraps the black phosphorus nanosheets, the overall size is average, and the layered structure has not changed.

[0057] In order to explore the effect of the ratio of black phosphorus to different drug weights on the overall drug loading rate, Pte dosages of 2, 4, 6, 8, and 10 times the weight of black phosphorus nanosheets were used for drug loading. Figure 2 shown.

[0058] from Figure 2 (A) It can be seen that when BP:Pte=1:6 (w / w%), the drug loading rate is 89.5%, reaching the highest. Figure 2 (B) It can be seen that when BP:Pte=1:6, the absorption peak of the full wavelength spectrum is the highest.

[0059] The particle size distribution and potential distribution of black phosphorus nanosheets, black phosphorus nanosheets loaded with pterostilbene composites (BP-Pte), and black phosphorus nanosheets modified with polydopamine (BP-Pte@PDA) were analyzed. Figure 3 shown.

[0060] from Figure 3 It can be seen from (A) that the size of black phosphorus nanosheets is 255.7±3.9nm, the size of BP-Pte is 263.1±2.3nm, and the size of BP-Pte@PDA is 277.9±7.8nm. There is no obvious volume change of black phosphorus nanosheets after drug loading and PDA modification. Figure 3 (B) shows that the Zeta potential of black phosphorus nanosheets is -22.9±1.2mV, the Zeta potential of BP-Pte is -17.6±0.7mV, and the Zeta potential of BP-Pte@PDA is -20.5±2.0mV. The absolute values ​​of the Zeta potential of drug-loaded BP-Pte and polydopamine-modified BP-Pte@PDA are lower than those of pure black phosphorus nanosheets.

[0061] In order to compare the photothermal effect of black phosphorus nanosheets and polydopamine-modified black phosphorus nanosheet composites, the temperature changes of PBS, black phosphorus nanosheet solution and polydopamine-modified black phosphorus nanosheet drug delivery system solution under near-infrared laser irradiation, the influence of different powers of near-infrared laser on the temperature of the polydopamine-modified black phosphorus nanosheet drug delivery system solution, the temperature changes of different concentrations of polydopamine-modified black phosphorus nanosheet drug delivery system solution under near-infrared laser irradiation, and the temperature changes of the polydopamine-modified black phosphorus nanosheet drug delivery system solution after 5 cycles of near-infrared light switching were investigated. The results are shown in Figure 2. Figure 4 shown.

[0062] from Figure 4 It can be seen from (A) that compared with the PBS group, the temperature change of the black phosphorus nanosheets is smaller than that of the polydopamine-modified black phosphorus nanosheets drug delivery system. Figure 4 As can be seen in (B), with the increase of power, the temperature of the polydopamine modified black phosphorus nanosheet drug delivery system solution increased significantly after 10 minutes of irradiation. Figure 4 As can be seen in (C), as the concentration of the solution increases, the temperature of the polydopamine-modified black phosphorus nanosheet drug delivery system solution increases significantly after irradiation for 10 minutes. Figure 4 As can be seen in (D), during the five cycles of near-infrared laser irradiation switching, the temperature rises slowly when it is heated up, and there is no obvious difference in the maximum temperature, indicating good stability.

[0063] In order to investigate the stability of black phosphorus nanosheets, black phosphorus nanosheets loaded with pterostilbene composites, and polydopamine modified black phosphorus nanosheets drug delivery system solutions, the full wavelength of ultraviolet light was used to compare the changes in 1, 4, and 7 days. The results are as follows Figure 5 shown.

[0064] from Figure 5 As can be seen from (A), the full wavelength of the black phosphorus nanosheet changes greatly over a week and is relatively unstable. Figure 5 As can be seen from (B), the full wavelength of the black phosphorus nanosheet-loaded pterostilbene composite material on the 7th day is higher than that on the 4th day, but smaller than that on the 1st day, indicating that it is less stable. Figure 5 As can be seen in (C), the full wavelength of the polydopamine-modified black phosphorus nanosheet drug delivery system solution gradually increases, and the stability is good. This is because polydopamine is modified on the black phosphorus surface, making the black phosphorus nanosheet more stable.

[0065] Test Example 2

[0066] In this experimental example, the biosafety of black phosphorus nanosheet drug delivery system modified with polydopamine (BP-Pte@PDA) at different concentrations was evaluated.

[0067] In order to investigate the hemolysis rate of different concentrations of polydopamine modified black phosphorus nanosheet drug delivery system (BP-Pte@PDA), a hemolysis experiment was conducted. Mouse blood was placed in an EP tube with sodium heparin, centrifuged at 1500rpm, 4℃ for 10min, the supernatant was removed to obtain mouse red blood cells, and saline was added to wash 2-3 times until the supernatant was clear. The purified red blood cells were made into a 4% red blood cell suspension, and an appropriate amount of red blood cell suspension was taken into an EP tube for standby use. The hemolysis experiment was divided into 6 groups, negative group: 100μL of saline was added to the tube; positive group: 100μL of ultrapure water was added to the tube; different concentrations of BP-Pte@PDA groups, 100μL of BP-Pte@PDA (50, 100, 150, 200μg / ml) PBS suspension was added to the tube. All groups were incubated in a 37°C incubator for 3 h. After incubation, the cells were centrifuged at 2500 rpm and 4°C for 5 min. 200 μL of the culture medium was accurately pipetted into a 96-well plate. The OD value at 540 nm was measured and the hemolysis rate was calculated. The results are shown in Table 1. Figure 6 shown.

[0068] from Figure 6 It can be seen that the hemolysis rate of BP-Pte@PDA does not exceed 5% as the concentration continues to increase, and no obvious hemolysis is shown.

[0069] Test Example 3

[0070] In this test example, the drug content in the blood and brain of mice in the pterostilbene administration group and the near-infrared irradiation polydopamine-modified black phosphorus nanosheet drug delivery system administration group was evaluated to assess whether it can pass through the blood-brain barrier.

[0071] In order to investigate the blood-brain barrier permeability of the polydopamine-modified black phosphorus nanosheet drug delivery system, UPLC was used to measure the drug content. Drawing of the Pte standard curve: 10.0 mg of Pte was accurately weighed and placed in a 10 ml volumetric flask, dissolved in methanol and diluted to the mark. The mother solution concentration was 1.0 mg / ml, and the corresponding series of standard concentrations (5, 10, 20, 40, 60, 90 μg / ml) were prepared, and the drug concentration gradient in the tissue was 0.5, 1, 2, 4, 6, 9 μg / ml. The preparation of the Pte gradient concentration should be carried out at room temperature, under which Pte has good stability. The peak area (Y, A) of the Pte standard reference substance was linearly regressed against the corresponding concentration (X, μg / ml) to obtain the tissue standard curve equation. Detection of Pte drug concentration in blood and brain tissue: The mice were divided into 2 groups (n=3): ①Pte group; ②BP-Pte@PDA+NIR irradiation group;. All mice were injected with drugs through the tail vein. Group ② was treated with 808 nm laser (1 W cm 2) were irradiated for 10 min. Plasma samples were collected from the tail vein at 0.083, 0.25, 0.5, 1, 2, 4, 6, 8, 12, and 24 h after administration, and brain samples were collected after cardiac perfusion at 0.25, 0.5, 1, 2, 4, 6, 8, 10, 12, and 24 h, and tissue homogenates were prepared and processed to remove proteins. The Pte content in all samples was measured using UPLC. The pharmacokinetic parameters, including the peak concentration (Cmax) of Pte in plasma or brain, the elimination half-life (T1 / 2), the area under the Pte concentration-time curve in plasma or brain (AUC0-t), and the mean residence time (MRT0-t), were calculated using DAS (Drug and Statistics) 2.0 software. Results are shown in Figure 7 , Figure 8 and Fig. 9 As shown, A is the Pte content in plasma; B is the Pte content in brain tissue; Figure 8 is the pharmacokinetic parameter of plasma; Fig. 9 Pharmacokinetic parameters of brain tissue.

[0072] from Figure 7 (A) and Figure 8 It can be seen that the Pte content in the plasma of the single-drug group is higher than that of the preparation group, and the pharmacokinetic parameters are greater than those of the preparation group. Figure 7 (B) and Fig. 9 It can be seen that the content of Pte in the preparation group in brain tissue is significantly higher than that in the single-dose group. From the pharmacokinetic parameters, it can also be seen that Pte can be delivered to the brain more from the preparation. The above can be concluded that compared with single-dose administration, the polydopamine-modified black phosphorus nanosheet drug delivery system can penetrate the blood-brain barrier to reach the brain and release drugs.

Claims

1. A black phosphorus nanosheet drug delivery system for enhancing the blood-brain barrier permeability of pterostilbene, characterized in that The sheet-like black phosphorus nanosheets are modified with polyethylene glycol (PEG) and combined with the model drug pterostilbene through electrostatic adsorption, and then the black phosphorus nanosheets are surface-modified with polydopamine (PDA). The black phosphorus nanosheet drug delivery system has good stability, can stably release pterostilbene in the brain under near-infrared laser irradiation, and has good biosafety and low toxicity.

2. The black phosphorus nanosheet drug delivery system according to claim 1, characterized in that: The particle size of the black phosphorus nanosheets is 100-200 nm.

3. The black phosphorus nanosheet drug delivery system according to claim 1, characterized in that: The particle size of the black phosphorus nanosheet-loaded rosewood stilbene composite material is 200-250nm.

4. The black phosphorus nanosheet drug delivery system according to claim 1, characterized in that: The particle size of the polydopamine-modified black phosphorus nanosheet composite material is 250-300 nm.

5. The black phosphorus nanosheet drug delivery system according to claim 1, characterized in that: The mass ratio of the black phosphorus nanosheets to the PEG is 1:

10.

6. The black phosphorus nanosheet drug delivery system according to claim 1, characterized in that: The mass ratio of the black phosphorus nanosheets to the resveratrol is 1:

6.

7. The black phosphorus nanosheet drug delivery system according to claim 1, characterized in that: The mass ratio of the black phosphorus nanosheets to the polydopamine is 1:7.

5.

8. A method for preparing the black phosphorus nanosheet drug delivery system according to claims 1 to 7, characterized in that: The preparation method of the polydopamine modified black phosphorus nanosheet drug delivery system is as follows: take an appropriate amount of black phosphorus nanosheet solution, centrifuge, and remove the supernatant. Take an appropriate amount of polyethylene glycol amine, dissolve it in pure water, add it to the black scale nanosheet precipitate, shake it in the dark under low temperature, and centrifuge it at high speed under low temperature to obtain a precipitate. Take an appropriate amount of stilbene, dissolve it in an equal volume of solvent, add the stilbene solution to the polyethylene glycol modified black phosphorus nanosheet precipitate, shake it in the dark under low temperature, and centrifuge it at high speed under low temperature to obtain a precipitate. Take an appropriate amount of dopamine hydrochloride and dissolve it in an appropriate amount of pure water, add it to the above precipitate, adjust the pH to 8.5, shake it in the dark under low temperature conditions, centrifuge it at high speed under low temperature conditions, add ultrapure water to the precipitate and re-suspend it to obtain a solution of polydopamine-modified black phosphorus nanosheet drug delivery system (BP-Pte@PDA).

9. The method for preparing the black phosphorus nanosheet drug delivery system according to claim 8, characterized in that: The solvent is selected from at least one of PEG400, ethanol, and dimethyl sulfoxide (DMSO).

10. The method for preparing the black phosphorus nanosheet drug delivery system according to claim 8, characterized in that: The high-speed low-temperature centrifugation conditions are 12000 rpm, 4°C, and the light-proof shaking time is 12h or 48h.

11. A stable blood-brain barrier permeable preparation according to any one of claims 1 to 7.

12. Use of the polydopamine-modified black phosphorus nanosheet drug delivery system according to any one of claims 1 to 7 in improving the blood-brain barrier permeability of pterostilbene.

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