A near-infrared light-responsive drug delivery system, its preparation method and application

Abstract

This invention discloses a near-infrared light-responsive drug delivery system, its preparation method, and its applications. The system comprises upconversion nanoparticles, a mesoporous silica shell coating the surface of the upconversion nanoparticles, drug molecules adsorbed within the pores of the mesoporous silica shell, a near-infrared dye coupled to the surface of the mesoporous silica shell, adamantane coupled to the near-infrared dye, and β-cyclodextrin complexed with the adamantane. This nanoparticle-based drug delivery system stably encapsulates drug molecules within mesopores, enabling rapid release in response to low-power-density near-infrared light (700-900 nm) irradiation based on the self-sensitized photooxidation bond breaking of the near-infrared dye within the system. Furthermore, controlling the irradiation time can meet the requirements for quantitative drug delivery. In addition, the upconversion luminescence of this nanoparticle-based drug delivery system under 980 nm laser excitation does not affect the release of drug molecules, enabling drug localization and bioimaging functions.

Description

Technical Field

[0001] This invention belongs to the field of nanomedicine delivery technology, specifically relating to a near-infrared light-responsive drug delivery system, its preparation method, and its application. Background Technology

[0002] Surface-functionalized nanoparticle drug delivery systems can be stimulated by various external factors (such as light, pH, and temperature) to achieve controlled drug release. Among these factors, light offers advantages such as being clean and non-invasive, remotely controllable, and having high spatiotemporal resolution. In particular, near-infrared light in the 700-950 nm wavelength range has deep tissue penetration and is less likely to cause photodamage. Therefore, near-infrared light-responsive nanoparticle drug delivery systems have attracted widespread attention in the biomedical field.

[0003] Rare-earth-doped upconversion nanoparticles can be excited by near-infrared light, generating ultraviolet-visible-near-infrared (UV-Vis-NIR) fluorescence emission through continuous photon absorption and energy transfer of rare-earth ions. Currently, near-infrared light-excited nanoparticle drug delivery systems mainly rely on near-infrared light to excite upconversion nanoparticles to generate ultraviolet light, causing ultraviolet light-sensitive groups such as azobenzene, nitrobenzyl, and coumarin to break or isomerize, thereby destroying the nanocarrier structure and releasing the drug. However, the upconversion efficiency of the ultraviolet emission portion is generally low and requires high-power-density laser irradiation, thus limiting its practical application. Another near-infrared light response mode utilizes the visible light emission of upconversion nanoparticles to excite photosensitizers to generate singlet oxygen, which then destroys sensitive molecules to release the drug. However, the types of singlet oxygen-responsive molecules currently available are limited (currently only thioketal molecules and dithioolefin molecules have been reported), and this process is also limited by factors such as energy transfer efficiency and singlet oxygen diffusion distance, resulting in low photoresponse efficiency of nanoparticle drug delivery systems. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a near-infrared photoresponsive drug delivery system, its preparation method, and its application. The drug delivery system of this invention is a photoresponsive rare-earth upconversion nanoparticle drug delivery system based on near-infrared dye photolysis. By constructing a novel upconversion nanoparticle drug delivery system with efficient near-infrared dyes as photoresponsive molecules, the near-infrared dyes can be directly excited by low-power-density near-infrared lasers (700-900 nm) to undergo self-sensitive photooxidation bond breaking, thereby releasing the loaded drug.

[0005] To achieve the above objectives, the following technical solution is adopted:

[0006] A drug delivery system comprising upconversion nanoparticles, a mesoporous silica shell coating the surface of the upconversion nanoparticles, drug molecules adsorbed within the pores of the mesoporous silica shell, a near-infrared dye coupled to the surface of the mesoporous silica shell, adamantane coupled to the near-infrared dye, and β-cyclodextrin complexed with adamantane.

[0007] According to an embodiment of the present invention, the mesoporous silica shell is an amino-modified mesoporous silica shell. Preferably, the mesoporous silica shell is linked to the near-infrared dye via an amide bond (-C(=O)-NH-).

[0008] According to an embodiment of the present invention, the near-infrared dye is linked to adamantane via an amide bond.

[0009] According to an embodiment of the present invention, the upconversion nanoparticles are rare-earth ion-doped upconversion nanoparticles, such as Yb and Er ion-doped upconversion nanoparticles, thereby enabling Yb-sensitized Er upconversion luminescence under 980nm laser pumping. Exemplarily, the upconversion nanoparticles can be upconversion nanoparticles doped with Yb and Er ions, using NaYF4, NaGdF4, NaLuF4, LiYF4, etc., as matrix materials.

[0010] According to an embodiment of the present invention, the near-infrared dye is selected from cyanine near-infrared dyes with dicarboxyl groups that have self-sensitive photooxidation bond-breaking properties, preferably selected from dicarboxyl derivatives of indocyanine green fluorescent dyes, such as cypate and IR825.

[0011] The drug delivery system of the present invention can be applied to any drug molecules that can be accommodated within the pores of a mesoporous silica shell.

[0012] According to an embodiment of the present invention, the β-cyclodextrin encapsulates and complexes adamantane molecules together through a hydrophobic cavity.

[0013] According to an embodiment of the present invention, the particle size of the drug delivery system is 20-600 nm, exemplarily 20 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, and 600 nm.

[0014] According to an embodiment of the present invention, the mass ratio of the upconversion nanoparticles to the mesoporous silica shell is 5:7 to 20:7, with exemplary ratios of 5:7, 6:7, 7:7, 8:7, 9:7, 10:7, 11:7, 12:7, 13:7, 14:7, 15:7, 16:7, 17:7, 18:7, 19:7, and 20:7.

[0015] According to an embodiment of the present invention, the mass ratio of the drug molecule to the mesoporous silica shell is 3:28 to 5:28, with 3:28, 4:28, and 5:28 being exemplary.

[0016] According to an embodiment of the present invention, the mass ratio of the near-infrared dye to the drug molecule is 1:5 to 3:5, with 1:5, 2:5, and 3:5 being exemplary.

[0017] According to an embodiment of the present invention, the mass ratio of the adamantane to the drug molecule is 1:15 to 1:5, with exemplary ratios of 1:5, 1:10, and 1:15.

[0018] According to an embodiment of the present invention, the mass ratio of the β-cyclodextrin to the drug molecule is 2:5 to 4:5, with 2:5, 3:5, and 4:5 being exemplary.

[0019] According to an embodiment of the present invention, the particle size of the upconversion nanoparticles is 5-500 nm, preferably 15-120 nm, and exemplary values ​​are 5 nm, 15 nm, 50 nm, 100 nm, 120 nm, 200 nm, 300 nm, 400 nm, and 500 nm.

[0020] According to an embodiment of the present invention, the thickness of the mesoporous silica shell is 1 to 100 nm, preferably 5 to 30 nm, and exemplary values ​​are 5 nm, 15 nm, 20 nm, 30 nm, 50 nm, and 100 nm.

[0021] According to an embodiment of the present invention, the pore size of the mesoporous silica shell is 1-30 nm, preferably 2-5 nm, and exemplary are 1 nm, 2 nm, 5 nm, 10 nm, 20 nm, and 30 nm.

[0022] According to an embodiment of the present invention, the particle size of the drug molecule is 0.1 to 30 nm, preferably 0.1 to 3 nm, and exemplary sizes are 0.1 nm, 1 nm, 3 nm, 5 nm, 10 nm, 20 nm, and 30 nm.

[0023] According to an embodiment of the present invention, the drug delivery system has near-infrared light response performance.

[0024] According to an embodiment of the present invention, when the drug delivery system is excited by near-infrared light (700-900 nm, for example 808 nm) with a low power density, the near-infrared dye undergoes self-sensitized photooxidative bond cleavage, leading to the release of adamantane (AD) and β-cyclodextrin (β-CD) molecules, thereby releasing drug molecules. Furthermore, upconversion emission excited by 980 nm near-infrared light can enable the localization of the nano-drug delivery system and perform functions such as bioimaging.

[0025] The present invention also provides a method for preparing the above-mentioned drug delivery system, comprising: using upconversion nanoparticles as the core, coating the surface of the upconversion nanoparticles with a mesoporous silica shell, coupling a near-infrared dye to the pores on the surface of the mesoporous silica shell, further connecting adamantane to load drug molecules, and then using the complexation effect of adamantane and β-cyclodextrin to seal the pores, thereby encapsulating the drug in the pores of the mesoporous silica shell, thus preparing the drug delivery system.

[0026] According to an embodiment of the present invention, the method for preparing the drug delivery system includes the following steps:

[0027] (1) Preparation of upconversion nanoparticles;

[0028] (2) Preparation of upconversion nanoparticles coated with mesoporous silica shell: The upconversion nanoparticles are coated with a mesoporous silica shell and then subjected to surface amino modification.

[0029] (3) Near-infrared dyes and adamantaneamine are sequentially coupled onto the surface of the amino-modified mesoporous silica shell obtained in step (2);

[0030] (4) Loading drug molecules in the mesoporous silica shell of the upconversion nanoparticles obtained in step (3);

[0031] (5) The pores on the surface of the material loaded with drug molecules obtained in step (4) are sealed with β-cyclodextrin.

[0032] Preferably, in step (1), the upconversion nanoparticles are prepared by thermal decomposition or high-temperature coprecipitation.

[0033] According to an exemplary embodiment of the present invention, the step of preparing upconversion nanoparticles may include: mixing yttrium acetate, ytterbium acetate, and erbium acetate powders in a molar ratio of 40:9:1, adding oleic acid and octadecene in a volume ratio of 2:3, heating to 180°C under nitrogen protection and holding for 0–40 min to dissolve the rare earth acetate; then naturally cooling to room temperature, adding sodium hydrogen fluoride powder and heating to 250–310°C and holding for 60–100 min, finally cooling to room temperature; adding anhydrous ethanol and centrifuging, washing the centrifuged material multiple times with cyclohexane and anhydrous ethanol to obtain upconversion nanoparticles (UCNP).

[0034] Preferably, the ratio of the molar amount of sodium bifluoride to the total molar amount of acetate (the sum of the molar amounts of yttrium acetate, ytterbium acetate, and erbium acetate) is (1 to 3):1, with examples being 1:1, 2:1, and 3:1.

[0035] Preferably, in step (2), the step of coating the surface of the upconversion nanoparticles with a mesoporous silica shell is preferably performed using a sol-gel method. For example, a surfactant (e.g., hexadecyltrimethylammonium bromide (CTAB)) can be used as a pore-forming agent.

[0036] According to an exemplary embodiment of the present invention, the step of coating the surface of upconversion nanoparticles with a mesoporous silica shell may include: mixing hexadecyltrimethylammonium bromide (CTAB), water and the above-mentioned cyclohexane solution of UCNP, heating to remove cyclohexane to obtain an aqueous solution of UCNP, and then adding tetraethyl orthosilicate to the solution to react and obtain the mesoporous silica-coated upconversion nanoparticles.

[0037] Preferably, the mass ratio of CTAB:water:UCNP is 5:1:10.

[0038] Preferably, the heating temperature is 60-100℃, and an example is 80℃; the heating holding time is 1-2 hours.

[0039] Preferably, the step of coating the surface of the upconversion nanoparticles with a mesoporous silica shell may further include adding a mixed solvent of ethanol and water to the UCNP aqueous solution. For example, the volume ratio of water to ethanol in the mixed solvent is 20:3.

[0040] Preferably, the step of coating the surface of the upconversion nanoparticles with a mesoporous silica shell may further include adjusting the pH of the reaction mixture to 9-11, for example, pH=10.

[0041] Preferably, the reaction temperature for adding tetraethyl orthosilicate is 60–80°C, exemplarily 70°C; the reaction time is 1–2 hours.

[0042] Preferably, the step of coating the surface of the upconversion nanoparticles with a mesoporous silica shell may further include cooling the reaction solution to room temperature after the reaction is completed, centrifuging to collect the bottom precipitate, and washing it multiple times with anhydrous ethanol to obtain upconversion nanoparticles coated with a mesoporous silica shell.

[0043] Preferably, in step (2), the surface amino modification step can be as follows: the upconversion nanoparticles coated with a mesoporous silica shell are dispersed in anhydrous ethanol containing ammonia and 3-aminopropyltriethoxysilane, stirred, centrifuged, washed, and the product is added to an anhydrous ethanol solution of ammonium nitrate. The CTAB template is removed by heating, and the surface amino-modified mesoporous silica shell-coated upconversion nanoparticles are obtained.

[0044] Preferably, the mass ratio of the upconversion nanoparticles coated with a mesoporous silica shell to 3-aminopropyltriethoxysilane is 1000:1 to 10000:1, with examples being 1000:1, 2000:1, 5000:1, 8000:1, and 10000:1.

[0045] For example, the volume ratio of anhydrous ethanol, ammonia, and 3-aminopropyltriethoxysilane is 150:3:1.

[0046] For example, the stirring temperature is room temperature; the stirring time is 10 to 15 hours, for example, 12 hours.

[0047] For example, the solvent used for washing can be anhydrous ethanol; the number of washing cycles can be once, twice, or more, preferably three times.

[0048] Preferably, the concentration of the anhydrous ethanol solution of ammonium nitrate is 5-7 g / L, and exemplarily 6 g / L.

[0049] Preferably, the heating temperature is 45–60°C; and the heating time is 2–5 hours.

[0050] Preferably, in step (2), the surface amino modification step may further include: after the reaction is completed, cooling to room temperature, centrifuging to collect the bottom precipitate and washing it multiple times with anhydrous ethanol to remove the byproducts of the reaction, and obtaining upconversion nanoparticles UCNP@MS coated with a surface amino-modified mesoporous silica shell.

[0051] Preferably, in step (3), the mass ratio of the amino-modified mesoporous silica shell to the near-infrared dye and adamantane is 70:3:1 to 280:3:1, with examples being 70:3:1, 140:3:1, 210:3:1, and 280:3:1.

[0052] Preferably, in step (3), the near-infrared dye and adamantane are sequentially coupled on the surface of the amino-modified mesoporous silica shell by amide bond coupling. For example, the near-infrared dye is first activated with carboxylic acid and then coupled with the amino-modified mesoporous silica shell, and then the near-infrared dye is activated with carboxylic acid again and coupled with adamantane.

[0053] According to an exemplary embodiment of the present invention, step (3) is as follows: the carboxyl group of the near-infrared dye is activated with N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (NHS / EDC), and added to the ethanol dispersion of upconversion nanoparticles UCNP@MS coated with surface amino-modified mesoporous silica shell prepared in step (2). After reacting for 0-12 h, the bottom precipitate is collected by centrifugation and washed until the supernatant is colorless. The carboxyl group is activated again with NHS / EDC and then adamantane hydrochloride is added. After reacting for 0-12 h, the mixture is centrifuged and washed with water and ethanol to obtain nanoparticles coupled with near-infrared dye and adamantane.

[0054] Preferably, the mass ratio of the near-infrared dye to NHS and EDC is 10:1:1 to 5:1:2, with examples being 10:1:1, 9:1:1, 8:1:1, 7:1:1, 6:1:1, 5:1:1, and 5:1:2.

[0055] Preferably, in step (4), the mass ratio of the drug molecule to the coupled-modified upconversion nanoparticles is 20:3 to 20:1, with examples being 20:3, 20:2, and 20:1.

[0056] Preferably, in step (4), the step of loading drug molecules can be: dispersing the upconversion nanoparticles after coupling and modifying near-infrared dye and adamantane in a drug molecule solution, and rotating and mixing for 0 to 24 hours to allow the drug molecules to diffuse into the pores of the mesoporous silica shell.

[0057] Preferably, in step (5), the mass ratio of the material loaded with drug molecules to β-cyclodextrin is 60:1 to 30:1, with examples being 60:1, 50:1, 40:1, and 30:1.

[0058] Preferably, in step (5), the step of β-cyclodextrin blocking the pores can be: adding β-cyclodextrin to the solution in step (4) and continuing to rotate and mix for 0 to 48 hours, so that it complexes with adamantane to block the pores, thereby obtaining nanoparticles loaded with drug molecules.

[0059] The present invention also provides the application of the above-described drug delivery system in the preparation of antibacterial drugs.

[0060] When the drug delivery system of the present invention is mixed with bacteria, it is irradiated with an 808nm laser, and the near-infrared dye photo-oxidation breaks the bonds, causing the molecules blocking the mesopores to detach, the pores to open and release drug molecules, thereby inhibiting bacterial reproduction.

[0061] The present invention also provides the application of the above-described drug delivery system in up-conversion imaging.

[0062] The beneficial effects of this invention:

[0063] By linking mesoporous structures with adamantane-cyclodextrin complexes using near-infrared dyes, drug molecules are stably encapsulated within mesoporous silica. Utilizing the self-sensitized photo-oxidative bond-breaking properties of the near-infrared dyes, drugs can be rapidly released under low-power-density 700-900 nm near-infrared light conditions, and the irradiation time can be controlled to meet different drug delivery needs. Furthermore, the upconversion nanoparticles possess bioimaging capabilities, thus enabling integrated diagnosis and treatment. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the near-infrared light-responsive drug delivery system constructed according to the present invention.

[0065] Figure 2 These are transmission electron micrographs of the upconversion nanoparticles (A) and the mesoporous silica-coated upconversion nanoparticles (B) prepared in Example 1 of this invention.

[0066] Figure 3 This is a diagram illustrating the photolysis mechanism of the near-infrared dyes cypate and IR825.

[0067] Figure 4 At a power density of 0.5 W·cm -1 The absorption curve of the near-infrared dye cypate changes under 808nm laser illumination for 0-40 minutes.

[0068] Figure 5 At a power density of 0.5 W·cm -1 Release curves of ofloxacin (OFL) under different irradiation times with an 808nm laser.

[0069] Figure 6 This is a diagram showing the antibacterial effect of a nano-drug delivery system against Staphylococcus aureus under different conditions.

[0070] Figure 7 These are CLSM images of Staphylococcus aureus incubated by a nano-drug delivery system, where (i) and (ii) are bright-field images and green upconversion luminescence images under 980nm laser illumination, respectively. Detailed Implementation

[0071] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0072] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0073] The equipment used in this embodiment is as follows:

[0074] Transmission electron microscope: Model JSM-6700F, manufactured by JEOL.

[0075] Infrared tester: Model Lambda 900, manufactured by Perkin-Elmer.

[0076] Example 1: Preparation of near-infrared light-responsive nanomaterials for drug delivery

[0077] (1) Preparation of upconversion nanoparticles by thermal decomposition

[0078] Weigh 0.8 mmol of yttrium acetate, 0.18 mmol of ytterbium acetate, and 0.02 mmol of erbium acetate powder into a 100 mL round-bottom flask, add 8 mL of oleic acid and 12 mL of octadecene, purge the air from the flask with nitrogen, and then heat to 180 °C and hold for 20 min to allow the rare earth acetates to completely dissolve in the organic solvent. Then, allow the mixture to cool naturally to room temperature, add 2 mmol of sodium hydrogen fluoride powder, and heat to 250 °C and hold for 30 min. Next, continue heating to 310 °C and hold for 60 min, finally cooling to room temperature. Add anhydrous ethanol to the solution and centrifuge. Wash the centrifuged mixture multiple times with cyclohexane and anhydrous ethanol to obtain upconversion nanoparticles (UCNP nanocrystals). The transmission electron microscope (TEM) image is shown below. Figure 2 As shown in Figure (A), it can be seen from the figure that the upconversion nanoparticles are hexagonal with an average size of about 120 nm and good dispersibility.

[0079] (2) Mesoporous silica coating and amino modification

[0080] Weigh 100 mg of hexadecyltrimethylammonium bromide and add it to a 100 mL round-bottom flask. Then, use a pipette to transfer 20 mL of ultrapure water and sonicate for 30 min to fully dissolve the hexadecyltrimethylammonium bromide. Then, add 2 mL of cyclohexane solution of UCNP nanocrystals prepared in step (1) with a concentration of 100 mg / mL. Sonicate for 30 min to mix it thoroughly, and then heat to 80 °C and keep warm for 30 min to remove the cyclohexane solvent. Finally, a clear and transparent aqueous solution of UCNP nanocrystals is obtained. Using a pipette, 20 mL of ultrapure water and 3 mL of anhydrous ethanol were added to a 100 mL round-bottom flask. Then, 150 μL of a 2 mmol / mL sodium hydroxide aqueous solution was added, followed by 10 mL of the aforementioned clear and transparent UCNP nanocrystal aqueous solution. The mixture was heated to 70 °C with stirring, and then 200 μL of tetraethyl orthosilicate was added. The reaction was allowed to proceed for 1 h. After cooling to room temperature, the supernatant was separated from the precipitate by centrifugation. The supernatant was discarded, and the bottom precipitate was washed several times with anhydrous ethanol and dispersed in 60 mL of a solution containing 1.2 mL of ammonia and 400 μL of sodium hydroxide solution. 3-Aminopropyltriethoxysilane was stirred in anhydrous ethanol at room temperature for 12 h, centrifuged, and washed three times with anhydrous ethanol. The product was then added to 50 mL of anhydrous ethanol containing 0.3 g ammonium nitrate, heated to 60 °C for 2 h, cooled to room temperature, and centrifuged to separate the supernatant from the precipitate. The supernatant was discarded, and the bottom precipitate was washed several times with anhydrous ethanol to remove reaction byproducts, yielding mesoporous silica-coated and amino-modified UCNP@MS. Its transmission electron microscopy (TEM) image is shown below. Figure 2 As shown in Figure (B), it can be seen from the figure that UCNP@MS has a spherical structure, with mesoporous silica uniformly coating the surface of UCNP, and the thickness of the mesoporous silica shell is about 30 nm.

[0081] (3) Coupling of cypate and adamantane via amide bonds

[0082] Take 2 mL of MES solution with pH 5.5, add 2 mg EDC and 1.6 mg NHS to dissolve, then add 400 μL of DMF solution of cypate with a concentration of 5 mg / mL and stir for 20 min to activate the carboxyl groups. Add 3 mL of ethanol dispersion of UCNP@MS with a concentration of 4 mg / mL prepared in step (2), stir overnight, centrifuge to obtain the product, and wash the supernatant with methanol until colorless to obtain UCNP@MS-cypate nanoparticles. Disperse 12 mg of the above UCNP@MS-cypate nanoparticles in 2 mL of MES solution, add 2 mg EDC and 1.6 mg NHS to activate the carboxyl groups, then add 15 mg adamantane hydrochloride and stir for 12 h. Centrifuge and wash to obtain UCNP@MS-cypate-AD nanoparticles.

[0083] (4) Drug loading and pore sealing of nano-drug delivery systems

[0084] The UCNP@MS-cypate-AD nanoparticles obtained after coupling modification in step (3) were freeze-dried to obtain a solid powder. 5 mg of the solid powder was weighed into 5 mL of ofloxacin (OFL) solution (0.5 mg / mL), and the mixture was rotated and mixed for 24 h to allow the drug to fully diffuse into the mesoporous channels of the UCNP@MS-cypate-AD obtained after coupling modification. Then, 50 mg of β-cyclodextrin (β-CD) was added, and the mixture was continuously rotated for 48 h to allow it to fully complex with adamantane molecules to block the mesoporous pores.

[0085] Example 2: Preparation of near-infrared light-responsive nanomaterials for drug delivery

[0086] The difference from Example 1 is that the near-infrared dye used is IR825. Everything else is the same as in Example 1.

[0087] The photolysis mechanism of the near-infrared dyes (cypate and IR825) in the near-infrared light-responsive nanomaterials prepared in Examples 1 and 2 under near-infrared light irradiation is as follows: Figure 3 As shown. At a power density of 0.5 W·cm⁻¹ -1 During 40 minutes of irradiation with an 808nm laser, the near-infrared dye cypate in the nano-drug-loaded system prepared after drug loading and pore blocking in step (4) of Example 1 underwent efficient photo-oxidative bond breaking, and the absorption curve changed as follows. Figure 4 As shown. From Figure 4 As can be seen, the absorption peak intensity of the near-infrared dye cypate first decreases rapidly, and then the change tends to be gradual. After irradiation with 808nm laser for 10 min and 30 min, the absorption peak intensity decreases to 60% and 70%, respectively.

[0088] The method for testing drug release is as follows: First, the standard curve of the drug is tested by ultraviolet spectrophotometry; then, 3.5 mg of drug-loaded nanoparticles prepared by drug loading and pore blocking in step (4) of Example 1 are weighed and placed in the corner of a cuvette. 2 mL of 0.1 mol / L PBS buffer solution with pH = 7.2 is added. Then, the nanoparticles in the corner are continuously irradiated with an 808 nm laser for different times (10 min, 20 min, 40 min, 120 min). The released OFL solution is tested by ultraviolet spectrophotometry at the set time interval. The concentration of OFL drug released at different times is obtained by comparing the ultraviolet absorbance value with the standard curve of OFL drug. Then, the release amount of OFL drug is calculated. The ratio of the release amount of OFL drug to the loading amount is the release percentage. At the same time, a control experiment is carried out in the dark.

[0089] Figure 5To achieve a power density of 0.5 W·cm -1 The release curves of the drug OFL in the nano-drug-loaded system prepared after drug loading and pore sealing in step (4) of Example 1 were obtained under different irradiation times of 808nm laser. As can be seen from the figure, only 6.9% of OFL was released after 120 min in the dark, indicating that the nano-drug-loaded system of the present invention has a good encapsulation effect and a very low drug loss rate under non-responsive conditions. As the laser irradiation time increased to 10 min, 20 min and 40 min, the OFL release rate of the system gradually increased, and the release amounts after 120 min were 29.9%, 41.2% and 50.9% respectively. When the irradiation time increased to 120 min, the OFL release curve was similar to that of 40 min, indicating that most of the near-infrared dye cypate in the system had been photolyzed after 40 min, and continued irradiation would no longer affect the drug release in the nano-drug-loaded system.

[0090] Example 3: In vitro anti-Staphylococcus aureus activity of nano-drug-loaded materials:

[0091] After removing the frozen glycerol bacteria (Staphylococcus aureus) from -80℃, use a pipette tip to inoculate 1 μL of glycerol bacteria into 2 mL of LB medium and incubate at 37℃ on a shaker for several hours until the OD value is reached. 600 =0.5. Add 200 μL of diluted bacterial culture (CFU = 10) to a 96-well plate. 6 Add 0.6 mg of the nano-drug-loaded material prepared in step (4) of Example 1, irradiate with 808 nm laser light for 30 min, and then incubate on a shaker at 37 °C for 10 hours (experimental group, light + drug-loaded material). In addition to the above experimental groups, a blank control group with only bacteria and no treatment, a control group with only light (light) and a control group with only nano-drug-loaded material but no light (darkness + drug-loaded material) were also set up. Except for the different experimental treatments, all the above experimental operations and the number of experimental repetitions were the same. By monitoring the optical density value (OD) of bacteria at 600 nm. 600 The changes were used to evaluate the in vitro antibacterial activity of the nano-drug-loaded material. The antibacterial effect was as follows: Figure 6 As shown in the figure, the bacterial optical density values ​​of all control groups after 10 hours were above 1.3, while the bacterial optical density value of the experimental group after 10 hours of near-infrared light irradiation was 0.34. This indicates that the drug released from the nano-drug delivery system prepared in this invention has a good antibacterial effect.

[0092] Example 4: On-coat drug delivery materials and their application in imaging:

[0093] After removing the frozen glycerol bacteria (Staphylococcus aureus) from -80℃, use a pipette tip to inoculate 1 μL of glycerol bacteria into 2 mL of LB medium and incubate at 37℃ on a shaker for several hours until the OD value is reached.600 =0.5. Add 200 μL of diluted bacterial culture (CFU = 10) to a 96-well plate. 6 Add 0.6 mg of the drug-loaded nanomaterial prepared in step (4) of Example 1. Then, use near-infrared light (980 nm) to excite and generate upconversion green fluorescence.

[0094] Figure 7 These are CLSM images of Staphylococcus aureus incubated with a nano-drug delivery system, where (i) and (ii) are bright-field images and green upconversion luminescence images under 980 nm laser irradiation, respectively. As can be seen from the images, the nano-drug delivery system binds to the bacteria under 980 nm laser excitation, exhibiting significant upconversion green light emission.

[0095] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a drug delivery system, characterized in that, The preparation method includes the following steps: (1) Preparation of upconversion nanoparticles, wherein the upconversion nanoparticles are upconversion nanoparticles doped with rare earth ions; (2) Preparation of upconversion nanoparticles coated with mesoporous silica shell: The upconversion nanoparticles are coated with a mesoporous silica shell and the surface is modified with amino groups; The step of coating the surface of upconversion nanoparticles with a mesoporous silica shell was performed using the sol-gel method. The surfactant cetyltrimethylammonium bromide (CTAB) was used as a pore-forming agent; (3) Near-infrared dye and adamantane are sequentially coupled on the surface of the amino-modified mesoporous silica shell obtained in step (2): the carboxyl group of the near-infrared dye is activated first and then coupled with the amino-modified mesoporous silica shell, and then the carboxyl group of the near-infrared dye is activated again and coupled with adamantane. The near-infrared dye is selected from cyanine near-infrared dyes with dicarboxyl groups that have self-sensitive photo-oxidative bond-breaking properties. (4) Loading drug molecules into the mesoporous silica shell of the upconversion nanoparticles obtained in step (3); (5) The pores on the surface of the drug-loaded material obtained in step (4) are sealed with β-cyclodextrin; The system includes upconversion nanoparticles, a mesoporous silica shell coating the surface of the upconversion nanoparticles, drug molecules adsorbed in the pores of the mesoporous silica shell, a near-infrared dye coupled to the surface of the mesoporous silica shell, adamantane coupled to the near-infrared dye, and β-cyclodextrin complexed with adamantane.

2. The method for preparing the drug delivery system according to claim 1, characterized in that, The mesoporous silica shell is connected to the near-infrared dye via amide bonds; And / or, the near-infrared dye is linked to adamantane via an amide bond.

3. The method for preparing the drug delivery system according to claim 1 or 2, characterized in that, The particle size of the drug delivery system is 20~600 nm.

4. The method for preparing the drug delivery system according to claim 1 or 2, characterized in that, The mass ratio of the upconversion nanoparticles to the mesoporous silica shell is 5:7 to 20:

7.

5. The method for preparing the drug delivery system according to claim 1 or 2, characterized in that, The mass ratio of the drug molecules to the mesoporous silica shell is 3:28 to 5:

28.

6. The method for preparing the drug delivery system according to claim 1 or 2, characterized in that, The mass ratio of the near-infrared dye to the drug molecule is 1:5 to 3:

5.

7. The method for preparing the drug delivery system according to claim 1 or 2, characterized in that, The mass ratio of adamantane to drug molecules is 1:15 to 1:

5.

8. The method for preparing the drug delivery system according to claim 1 or 2, characterized in that, The mass ratio of β-cyclodextrin to drug molecules is 2:5 to 4:

5.

9. A method for preparing a drug delivery system according to any one of claims 1-2, characterized in that, The upconversion nanoparticles have a particle size of 5-500 nm; the mesoporous silica shell has a thickness of 1-100 nm; the mesoporous silica shell has a pore size of 1-30 nm; and the drug molecules have a particle size of 0.1-30 nm.

10. The use of the drug delivery system prepared by the method according to any one of claims 1-9 in the preparation of antibacterial drugs.

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