Chemotactic yin-yang type colloid motor as well as preparation method and application thereof

Abstract

The invention discloses a chemotactic yin-yang type colloidal motor and a preparation method and application thereof, the colloidal motor takes mesoporous silica nanoparticles as a drug carrier, a hydrophobic drug cannabidiol is loaded, and a Janus structure is constructed by coating a pH responsive chitosan layer on the surface and depositing a platinum catalyst layer on one side. According to the chemotactic yin-yang type colloid motor disclosed by the invention, the sensing of high-concentration H2O2 at an inflammation part can be realized through the asymmetrically modified platinum layer, and forward chemotactic movement is carried out along the concentration gradient, so that accurate targeting is realized, the obstacles of body fluid and the like in a biological environment are overcome, and accurate aggregation at the inflammation part is realized; meanwhile, the controllable release of the medicine in an acidic microenvironment of the colloid motor is realized through the coating of the chitosan, and the bioavailability of the medicine is improved, so that the anti-inflammatory effect is realized. The chemotactic yin-yang type colloid motor has the functions of efficient chemotactic targeting and intelligent controlled release, the preparation process is simple, the biocompatibility is good, and a new strategy is provided for precise treatment of inflammatory diseases.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano motors and drug delivery, and relates to a colloidal motor, specifically to a cationic and anionic colloidal motor with chemotactic and pH-responsive drug release functions, a preparation method thereof, and an application in inflammatory targeted therapy. Background Art

[0002] In the treatment of inflammation, the effectiveness of traditional nano-drugs is often limited by passive diffusion, limited active targeting, and poor selectivity, which hinders their ability to diffuse and precisely target the lesion site, and reduces the therapeutic effect. In recent years, the rapid development of colloidal motors has provided new solutions for breaking through various limitations in the application of traditional nano-carriers. In terms of construction methods, colloidal motors have gradually developed on the basis of the original synthesis routes to construct various asymmetric structures; in practical applications, colloidal motors can use external energies such as light, electricity, magnetism, and ultrasound, and have advantages in terms of their speed and controllability, solving the problem that nano-carriers cannot overcome passive diffusion. However, on the one hand, external field driving depends on external energy supply, requires the setting of external equipment support, and artificial regulation of parameters to achieve precise control. On the other hand, when colloidal motors enter pathological tissues for treatment, it is very difficult to monitor the treatment situation of the motors through ordinary detection means. Therefore, endowing colloidal motors with their own targeting ability is a key area and a very important challenge for future precise treatment. Summary of the Invention

[0003] Based on the above technical deficiencies, the present invention provides a chemotactic cationic and anionic colloidal motor, a preparation method thereof, and an application. The chemotactic cationic and anionic colloidal motor can sense a higher concentration of H2O2 at the inflammatory site through an asymmetrically modified platinum layer and perform positive chemotactic movement along the concentration gradient, thereby achieving precise targeting and overcoming obstacles such as body fluids in the biological environment, and precisely aggregating at the inflammatory site; at the same time, the coating of chitosan enables the colloidal motor to achieve controllable release of drugs in an acidic microenvironment, improving the bioavailability of drugs, thereby achieving an anti-inflammatory effect.

[0004] The object of the present invention is achieved through the following technical solutions:

[0005] A chemotactic cationic and anionic colloidal motor uses mesoporous silica nanoparticles as a drug carrier, loads the hydrophobic drug cannabidiol (CBD), and constructs a Janus structure by surface coating with a pH-responsive chitosan layer and unilateral deposition of a platinum (Pt) catalytic layer, wherein:

[0006] The particle size of the mesoporous silica nanoparticles is 400 - 900 nm, and the pore diameter is 2 - 3 nm;

[0007] The deposition thickness of the platinum (Pt) catalytic layer is 8 - 12 nm.

[0008] A preparation method of the above-mentioned chemotactic amphiphilic colloidal motor, comprising the following steps:

[0009] Step (1) Preparation of mesoporous silica nanoparticles: Sol-gel method is used to prepare silica nanoparticles, which are calcined at high temperature to form a mesoporous structure, and mesoporous silica nanoparticles are obtained. Among them: the high-temperature calcination temperature is 500-600 °C, and the calcination time is 5-7 h;

[0010] Step (2) Loading the lipophilic drug CBD: The mesoporous silica nanoparticles prepared in step (1) are mixed with the CBD-ethanol solution according to a mass ratio of 1:50-1:10, and drug-loaded nanoparticles are prepared by electrostatic adsorption. Among them: the concentration of the CBD-ethanol solution is 0.01-0.1 mg / mL;

[0011] Step (3) Coating a pH-responsive chitosan layer: The drug-loaded nanoparticles prepared in step (2) are uniformly dispersed in the chitosan-acetic acid solution, and the chitosan layer is coated by magnetic stirring to achieve pH-dependent drug release. Among them: the concentration of the chitosan-acetic acid solution is 0.4-0.8% w / v;

[0012] Step (4) Preparation of an asymmetric-structured colloidal motor: A platinum catalytic layer is vacuum sputtered on one side of the particles prepared in step (3) by physical vapor deposition, and an asymmetric platinum catalytic layer is constructed to form a Janus structure, endowing self-propelling ability. Among them: the intensity of vacuum sputtering is 13-16 mA, and the time is 200-250 s.

[0013] The present invention makes full use of mesoporous silica nanoparticles with good biocompatibility as a drug carrier, and chitosan is coated to achieve low-pH-responsive drug release. The asymmetric sputtering of the platinum layer enables the colloidal motor to exhibit motion characteristics in a higher concentration of H2O2 at the inflammatory site and the ability to chemotax along the H2O2 concentration gradient. In view of the characteristic that the chitosan polymer has a structural change at a lower pH value, the cumulative release rate of CBD by the chemotactic amphiphilic colloidal motor under normal conditions (pH = 7.4) and acidic conditions (pH = 6.5) was studied. At pH = 6.5, the release efficiency of CBD increased significantly, attributed to the conformational change of the chitosan molecular structure. In an acidic environment, the primary amine in its structure is easily protonated to become NH3 +(pKa = 6.5), which causes its structure to expand. Coupled with stronger electrostatic repulsion and weaker hydrogen bonding between molecular chains, it promotes the release of CBD. Given the characteristics that the asymmetrically modified platinum layer can catalyze the decomposition of H2O2 to produce O2 and has chemotactic behavior under the H2O2 concentration gradient, the behavior of chemotactic cationic and anionic colloidal motors in the H2O2 concentration (0.1 - 1 mM) at the simulated inflammatory site and their chemotactic movement in the horizontal direction were studied. In the H2O2 solution, as its concentration increases, the diffusion coefficient of the motor increases from 0.61 μm / s 2 (Brownian motion) to 1.43 μm / s when in the solution 2 (1 mM H2O2), achieving self-propelled motion. In the inflammatory-normal cell environment, the ability of chemotactic cationic and anionic colloidal motors to achieve directed movement towards inflammatory cells and continuous and effective accumulation improves the targeting efficiency of inflammatory cells by 1.5 times compared to normal cells.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The present invention prepares a chemotactic cationic and anionic colloidal motor. Through the collaborative design of Janus structure Pt layer catalysis and chitosan pH response, the chemotactic cationic and anionic colloidal motor realizes dual intelligent responses of self-chemotactic targeting and microenvironment-triggered release.

[0016] 2. The chemotactic cationic and anionic colloidal motor of the present invention can achieve the ability to move directionally towards inflammatory cells and continuously and effectively accumulate through the asymmetric platinum layer, and the targeting efficiency of inflammatory cells is increased by 1.5 times compared to normal cells.

[0017] 3. The chemotactic cationic and anionic colloidal motor of the present invention can achieve the ability to precisely respond and control the release of drug CBD after reaching the inflammatory site; the outer layer coated with a chitosan layer with good biocompatibility can achieve the ability to respond and release CBD in the inflammatory microenvironment with a pH of 6.0 - 6.8, and the 24-hour cumulative release rate of CBD reaches 60 - 80%, which is 2 times higher than the release rate under normal physiological pH conditions.

[0018] 4. In the simulated inflammatory condition of 0.1 - 1 mM H2O2, the colloidal motor shows self-propelled motion with a movement speed of 1.9 - 3 μm / s; under the H2O2 concentration gradient, the colloidal motor can automatically recognize the substrate gradient and show positive chemotactic behavior in both the vertical and horizontal directions.

[0019] 5. The colloidal motor of the present invention has good biocompatibility. The chemotactic cationic and anionic colloidal motor produces positive chemotactic movement through platinum-catalyzed decomposition and recognition of overexpressed H2O2 at the inflammatory site, and migrates along its concentration gradient to the lesion for precise targeting. In the acidic microenvironment, the relaxed structure of the chitosan layer can achieve response-controlled release of the drug and improve the drug utilization rate.

[0020] 6. The chemotactic yin-yang colloidal motor of the present invention can be used as a targeted osteoarthritis treatment system. The in vitro chemotactic yin-yang colloidal motor can enhance the internalization of inflammatory cells and play a dual role in significantly anti-inflammatory and anti-neuropathic pain; in vivo, the colloidal motor targets and actively accumulates at the inflamed site in the joint cavity. After treatment, male SD rats showed obvious remission in joint swelling, cartilage tissue damage and osteophyte formation, and at the same time showed good biosafety.

[0021] 7. The chemotactic yin-yang colloidal motor of the present invention combines high-efficiency chemotactic targeting and intelligent controlled release functions, has a simple preparation process and good biocompatibility, providing a new strategy for the precise treatment of inflammatory diseases. Brief Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the preparation process of the chemotactic yin-yang colloidal motor of the present invention;

[0023] Figure 2 It is a scanning electron microscope picture and hydrated particle size statistics of the chemotactic yin-yang colloidal motor;

[0024] Figure 3 It is a transmission electron microscope picture of the pores of the chemotactic yin-yang colloidal motor and mesoporous silica nanoparticles;

[0025] Figure 4 It is a fluorescence microscope picture of the chemotactic yin-yang colloidal motor;

[0026] Figure 5 It is an energy dispersive X-ray spectroscopy picture of the chemotactic yin-yang colloidal motor;

[0027] Figure 6 It is the cumulative release rate of CBD of the chemotactic yin-yang colloidal motor under the conditions of pH = 7.4 and pH = 6.5;

[0028] Figure 7 It is the diffusion coefficient statistics of the motor of the chemotactic yin-yang colloidal motor in a 0-1 mM H2O2 solution within 2 s;

[0029] Figure 8 It is a fluorescence intensity statistics picture of the chemotactic behavior of the chemotactic yin-yang colloidal motor in an in vitro inflammation model. Detailed Embodiments

[0030] The technical solutions of the present invention will be further described below in conjunction with the embodiments, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a chemotactic yin-yang type colloidal motor, as Figure 1 shown. First, mesoporous silica nanoparticles with a diameter of about 500 nm and a pore size of about 2 nm were synthesized by combining the sol-gel method with high-temperature calcination. Secondly, the prepared mesoporous silica nanoparticles were dispersed in a CBD-ethanol solution, and the drug CBD was loaded by electrostatic adsorption. Then, the drug-loaded nanoparticles were uniformly dispersed in a chitosan-acetic acid solution with a pH of 6.0. Finally, a platinum layer with a thickness of 10 nm was deposited on the surface of the nanoparticles by vacuum sputtering technology to synthesize a chemotactic yin-yang type colloidal motor. The specific steps are as follows:

[0033] Step 1. Preparation of mesoporous silica nanoparticles:

[0034] Step 1-1. Dissolve 0.16 g of the cationic surfactant cetyltrimethylammonium bromide (CTAB) in a mixed system (81 mL) with an ethanol / water volume ratio of 0.6. CTAB needs to be dissolved in water first, and ultrasonic dispersion is carried out for 10 min to fully dissolve it.

[0035] Step 1-2. Add 30.5 mL of ethanol solution and ultrasonic for 10 min to mix evenly.

[0036] Step 1-3. Add 1 mL of ammonia water (28%) and stir vigorously magnetically for about 30 min until the solution is transparent and clear.

[0037] Step 1-4. While stirring at a constant speed, add 1 mL of tetraethyl orthosilicate dropwise and evenly, and control the addition time within 2 min. Keep it reacting at a constant temperature of 25 °C, and the magnetic stirring speed is 500 rpm. Generally, the solution will start to turn milky white after stirring for about 5 min, and a milky white suspension is obtained after stirring for 6 h.

[0038] Step 1-5. Centrifuge and wash with deionized water 3 times, and dry in an oven at 50 °C for 6 h to obtain a dry white powder.

[0039] Step 1-6. Transfer the completely dried white powder to a quartz boat, cover it, and carefully place it in a tube furnace for calcination to remove the template CTAB. Program the temperature to rise to 550 °C, keep it calcined at a constant temperature for 6 h, and then cool it to room temperature at a rate of 1 °C / min. The obtained white dry powder is washed with water to obtain mesoporous silica nanoparticles.

[0040] Step 2. Loading the lipophilic drug CBD:

[0041] Step 2-1. Dissolve CBD in an ethanol solution to obtain a 0.1 mg / mL, 0.2 mL CBD-ethanol solution.

[0042] Step 2-2: Disperse 2 mg of the prepared mesoporous silica nanoparticles into the CBD-ethanol solution and magnetically stir for 24 h.

[0043] Step 2-3: The CBD-loaded mesoporous silica nanoparticles are collected by centrifugation at 10,000 r / min for 10 min, and after centrifuging three times with deionized water, they are stored in an aqueous solution.

[0044] Step 3: Coating the outer layer with a pH-responsive chitosan layer:

[0045] Step 3-1: Prepare a 0.6% (w / v) chitosan / acetic acid solution, where the concentration of the acetic acid solution is 10% (v / v), and adjust the pH of the chitosan / acetic acid solution to 6.0 with 1 M sodium hydroxide solution.

[0046] Step 3-2: Take 3 mg of the CBD-loaded mesoporous silica nanoparticles in a conical bottom centrifuge tube, add 1 mL of 0.6% (W / V) chitosan / acetic acid solution, and continuously magnetically stir for 24 h after the nanoparticles are evenly dispersed in the solution.

[0047] Step 3-3: Centrifuge, wash with water multiple times and store.

[0048] Step 4: Prepare an asymmetric chemotactic cationic and anionic colloidal motor:

[0049] Step 4-1: Ultrasonic clean the glass slide with isopropanol, acetone, and deionized water for 10 min each in turn. After drying, add concentrated sulfuric acid (98%) and hydrogen peroxide (30%) with a volume ratio of 7:3 to perform hydrophilic treatment on the glass slide, and a hydrophilic glass slide is obtained after 24 h.

[0050] Step 4-2: Use a pipette to transfer a certain amount of the nanoparticle dispersion, drop it on the hydrophilic glass slide, make the motor evenly spread out, and place it at room temperature to dry.

[0051] Step 4-3: Keep the glass slide at an inclination of 9 degrees to the horizontal direction and place it in a dish for preparation.

[0052] Step 4-4: Deposit a platinum metal layer on the surface of the well-dispersed nanoparticles by chemical vapor deposition using a metal vacuum sputtering instrument. The intensity of the vacuum sputtering is 15 mA and the time is 240 s.

[0053] Step 4-5: Slowly release the particles on the glass slide with a pipette, centrifuge and collect them to finally obtain the chemotactic cationic and anionic colloidal motor.

[0054] Example 2

[0055] This example provides a method for preparing a chemotactic cationic and anionic colloidal motor, as Figure 1As shown, first, mesoporous silica nanoparticles with a diameter of about 900 nm and a pore size of about 3 nm were synthesized by the sol-gel method combined with high-temperature calcination. Secondly, the prepared mesoporous silica nanoparticles were dispersed in a CBD-ethanol solution, and the drug CBD was loaded by electrostatic adsorption. Then, the drug-loaded nanoparticles were uniformly dispersed in a chitosan-acetic acid solution with a pH of 6.0. Finally, a platinum layer with a thickness of 12 nm was deposited on the surface of the nanoparticles by vacuum sputtering technology to synthesize a chemotactic amphoteric colloidal motor. The specific steps are as follows:

[0056] Step 1. Preparation of mesoporous silica nanoparticles:

[0057] Step 1-1. Dissolve 0.16 g of the cationic surfactant cetyltrimethylammonium bromide (CTAB) in a mixed system (81 mL) with an ethanol / water volume ratio of 0.75. CTAB needs to be dissolved in water first, and ultrasonic dispersion is carried out for 10 min to fully dissolve it.

[0058] Step 1-2. Add 34.7 mL of ethanol solution and ultrasonic for 10 min to mix evenly.

[0059] Step 1-3. Add 1 mL of ammonia water (28%) and stir vigorously magnetically for about 30 min until the solution is transparent and clear.

[0060] Step 1-4. While stirring at a constant speed, add 1 mL of tetraethyl orthosilicate dropwise and evenly. The addition time is controlled within 2 min, and it is allowed to react at a constant temperature of 22 °C with a magnetic stirring speed of 500 rpm. Generally, the solution will start to turn milky white after stirring for about 5 min, and a milky white suspension is obtained after stirring for 8 h.

[0061] Step 1-5. Centrifuge and wash with deionized water 3 times, and dry in an oven at 50 °C for 6 h to obtain a dry white powder.

[0062] Step 1-6. Transfer the completely dried white powder to a quartz boat, cover it, and carefully place it in a tube furnace for calcination to remove the template CTAB. The temperature is programmed to rise to 600 °C, and after constant-temperature calcination for 7 h, it is cooled to room temperature at a rate of 1 °C / min. The obtained white dry powder is washed with water to obtain mesoporous silica nanoparticles.

[0063] Step 2. Loading of the lipophilic drug CBD:

[0064] Step 2-1. Dissolve CBD in an ethanol solution to obtain a 0.08 mg / mL, 0.2 mL CBD-ethanol solution.

[0065] Step 2-2. Disperse 100 mg of the prepared mesoporous silica nanoparticles into the CBD-ethanol solution and stir magnetically for 24 h.

[0066] Step 2-3: The CBD-loaded mesoporous silica nanoparticles are collected by centrifugation at 10,000 r / min for 10 min, and centrifuged three times with deionized water and then stored in an aqueous solution.

[0067] Step 3: Coating the outer layer with a pH-responsive chitosan layer:

[0068] Step 3-1: Prepare a 0.8% (w / v) chitosan / acetic acid solution, where the concentration of the acetic acid solution is 10% (v / v), and adjust the pH of the chitosan / acetic acid solution to 6.0 with 1 M sodium hydroxide solution.

[0069] Step 3-2: Take 3 mg of the CBD-loaded mesoporous silica nanoparticles in a conical bottom centrifuge tube, add 1 mL of 0.8% (W / V) chitosan / acetic acid solution, and continuously stir magnetically for 24 h after the nanoparticles are evenly dispersed in the solution.

[0070] Step 3-3: Centrifuge and wash with water multiple times and store.

[0071] Step 4: Prepare an asymmetric chemotactic cationic and anionic colloidal motor:

[0072] Step 4-1: Ultrasonic clean the glass slide with isopropanol, acetone, and deionized water for 10 min each in turn. After drying, add concentrated sulfuric acid (98%) and hydrogen peroxide (30%) with a volume ratio of 7:3, and perform hydrophilic treatment on the glass slide. After 24 h, a hydrophilic glass slide is obtained.

[0073] Step 4-2: Use a pipette to transfer a certain amount of the nanoparticle dispersion liquid, drop it on the hydrophilic glass slide, make the motor spread evenly, and place it at room temperature to dry.

[0074] Step 4-3: Keep the glass slide at an angle of 9 degrees with the horizontal direction and place it in a dish for preparation.

[0075] Step 4-4: Deposit a platinum metal layer on the surface of the well-dispersed nanoparticles by chemical vapor deposition using a metal vacuum sputtering instrument. The intensity of the vacuum sputtering is 16 mA and the time is 250 s.

[0076] Step 4-5: Slowly release the particles on the glass slide with a pipette, centrifuge and collect them, and finally obtain the chemotactic cationic and anionic colloidal motor.

[0077] Example 3

[0078] This example provides a method for preparing a chemotactic cationic and anionic colloidal motor, as Figure 1As shown in the figure, first, mesoporous silica nanoparticles with a diameter of about 400 nm and a pore size of about 2 nm were synthesized by the sol-gel method combined with high-temperature calcination; second, the prepared mesoporous silica nanoparticles were dispersed in a CBD-ethanol solution, and the drug CBD was loaded by electrostatic adsorption; then, the drug-loaded nanoparticles were uniformly dispersed in a chitosan-acetic acid solution with a pH of 6.0; finally, a platinum layer with a thickness of 8 nm was deposited on the surface of the nanoparticles by vacuum sputtering technology to synthesize a chemotactic cationic and anionic colloidal motor. The specific steps are as follows:

[0079] Step 1. Preparation of mesoporous silica nanoparticles:

[0080] Step 1-1. Dissolve 0.16 g of the cationic surfactant cetyltrimethylammonium bromide (CTAB) in a mixed system (81 mL) with an ethanol / water volume ratio of 0.51. CTAB needs to be dissolved in water first, and ultrasonic dispersion is carried out for 10 min to fully dissolve it.

[0081] Step 1-2. Add 27.5 mL of ethanol solution and ultrasonic for 10 min to mix it evenly.

[0082] Step 1-3. Add 1 mL of ammonia water (28%) and stir vigorously magnetically for about 30 min until the solution is transparent and clear.

[0083] Step 1-4. While stirring at a constant speed, add 1 mL of tetraethyl orthosilicate dropwise and evenly, and control the addition time within 2 min. Keep it reacting at a constant temperature of 26 °C, and the magnetic stirring speed is 500 rpm. Generally, the solution will start to turn milky white after stirring for about 5 min, and a milky white suspension is obtained after stirring for 8 h.

[0084] Step 1-5. Centrifuge and wash with deionized water 3 times, and dry in an oven at 50 °C for 6 h to obtain a dry white powder.

[0085] Step 1-6. Transfer the completely dried white powder to a quartz boat, cover it, and carefully place it in a tubular furnace to calcine and remove the template CTAB. Program the temperature to rise to 500 °C, keep it calcined at a constant temperature for 5 h, and then cool it to room temperature at a rate of 1 °C / min. The obtained white dry powder is washed with water to obtain mesoporous silica nanoparticles.

[0086] Step 2. Loading of the lipophilic drug CBD:

[0087] Step 2-1. Dissolve CBD in an ethanol solution to obtain a 0.05 mg / mL, 0.2 mL CBD-ethanol solution.

[0088] Step 2-2. Disperse 6 mg of the prepared mesoporous silica nanoparticles into the CBD-ethanol solution and stir magnetically for 24 h.

[0089] Step 2-3: The CBD-loaded mesoporous silica nanoparticles were collected by centrifugation at 10,000 r / min for 10 min, centrifuged three times with deionized water, and then stored in an aqueous solution.

[0090] Step 3: Coating the outer layer with a pH-responsive chitosan layer:

[0091] Step 3-1: Prepare a 0.4% (w / v) chitosan / acetic acid solution, where the concentration of the acetic acid solution is 10% (v / v), and adjust the pH of the chitosan / acetic acid solution to 6.0 with 1 M sodium hydroxide solution.

[0092] Step 3-2: Take 5 mg of the CBD-loaded mesoporous silica nanoparticles in a conical bottom centrifuge tube, add 1 mL of 0.4% (W / V) chitosan / acetic acid solution, and continuously stir magnetically for 24 h after the nanoparticles are evenly dispersed in the solution.

[0093] Step 3-3: Centrifuge, wash with water multiple times, and store.

[0094] Step 4: Prepare an asymmetric chemotactic cationic and anionic colloidal motor:

[0095] Step 4-1: Ultrasonic clean the glass slide with isopropanol, acetone, and deionized water for 10 min each in turn. After drying, add concentrated sulfuric acid (98%) and hydrogen peroxide (30%) with a volume ratio of 7:3, and perform a hydrophilic treatment on the glass slide. After 24 h, a hydrophilic glass slide is obtained.

[0096] Step 4-2: Use a pipette to transfer a certain amount of the nanoparticle dispersion, drop it on the hydrophilic glass slide, make the motor spread evenly, and dry it at room temperature.

[0097] Step 4-3: Keep the glass slide at an inclination angle of 9 degrees with the horizontal direction and place it in a dish for preparation.

[0098] Step 4-4: Deposit a platinum metal layer on the surface of the well-dispersed nanoparticles by chemical vapor deposition using a metal vacuum sputtering instrument. The intensity of the vacuum sputtering is 13 mA and the time is 200 s.

[0099] Step 4-5: Slowly release the particles on the glass slide with a pipette, centrifuge and collect them to finally obtain a chemotactic cationic and anionic colloidal motor.

[0100] Example 4

[0101] Disperse the chemotactic cationic and anionic colloidal motor prepared in Example 1 on a silicon wafer. After drying, observe the morphology under a scanning electron microscope. Figure 2It can be seen that the colloidal motors are of uniform size and good dispersibility, with a particle size of about 500 nm and a Janus structure. The particle size distribution was statistically analyzed using a dynamic light scattering instrument, and the obtained particle size was concentrated at about 500 nm, which was consistent with the scanning electron microscopy results. The chemotactic Janus colloidal motors and mesoporous silica nanoparticles were respectively dropped onto a copper mesh, and the samples were naturally deposited and dried at room temperature for sample preparation. After injection using a transmission electron microscope, the morphology and pores of the chemotactic Janus colloidal motors and mesoporous silica nanoparticles were observed. Figure 3 The Janus structure of the colloidal motor is demonstrated. The mesoporous silica nanoparticles have an ordered mesoporous channel structure arranged from the center of the sphere to the outer surface, and the pore diameter is about 2 nm.

[0102] Example 5

[0103] Dissolve 1 mg of fluorescein isothiocyanate (FITC) in 3 mL of ethanol solution, place CBD in the solution and shake it in the dark, add mesoporous silica nanoparticles for CBD loading, stir magnetically in the dark for 24 h, centrifuge and wash repeatedly with deionized water. Then dissolve 1 mg of rhodamine B (RhB) in the pre-prepared 5 mL 0.6% W / V CS / acetic acid solution, shake it, and prepare chemotactic Janus colloidal motors according to the method of Example 1. The fluorescence staining images obtained by excitation at 488 nm and 554 nm observed using a fluorescence microscope are as Figure 4 shown. The green fluorescence comes from FITC-CBD (488 nm), and the red fluorescence comes from RhB-CS (554 nm). It can be observed from the fluorescence images that CBD and CS were successfully loaded into the motors, and the particle orientations in the two fluorescence images can coincide.

[0104] Example 6

[0105] Energy-dispersive X-ray spectroscopy analysis was performed on the chemotactic Janus colloidal motors prepared in Example 1 using a transmission electron microscope, as Figure 5 shown. The distributions of four elements, Si, O, N, and Pt, were characterized. Among them, Si and O are used to characterize the characteristic elements of mesoporous silica nanoparticles, N is used to characterize the characteristic element of chitosan, and the Pt element is used to show the Janus structure of the colloidal motor.

[0106] Example 7

[0107] Place 1 mg of the chemotactic cationic and anionic colloidal motor prepared in Example 1 into 1 mL of PBS buffer solution at 37 °C (pH = 7.4, pH = 6.5), continuously stir at a constant temperature at a rate of 30 r / min, take it down for centrifugation every 1 h, and take 300 μL of the supernatant. At the same time, quickly add 300 μL of PBS buffer solution at 37 °C (pH = 7.4, pH = 6.5) respectively. Finally, calculate the absorbance of the supernatant of each sample by ultraviolet spectrophotometry. Calculate its cumulative release rate within 12 h according to formula (1):

[0108]

[0109] In the formula, C n represents the concentration of the sample taken at the nth time point, V i is the sampling volume at the ith time point, C i is the concentration of the sample taken at the ith time point.

[0110] As Figure 6 shown, the hourly release amount of CBD in the chemotactic cationic and anionic colloidal motor in PBS at pH = 7.4 is relatively stable, indicating that the structure of the colloidal motor changes less in a neutral environment and has fewer side effects after long-term exposure to normal physiological conditions. The release efficiency of CBD is significantly increased at pH = 6.5. This enhanced release ability is mainly attributed to the conformational change of the chitosan molecular structure. The primary amine in chitosan is easily protonated to become NH3 + (pKa is about 6.5) in acidic conditions, which makes the structure in an expanded state. Coupled with stronger electrostatic repulsion and weaker hydrogen bond interaction between molecular chains, it promotes the release of the drug CBD.

[0111] Example 8

[0112] Combined with the concentration range of H2O2 at the inflammatory site, set H2O2 solutions of 0, 0.2, 0.4, 0.6, 0.8, 1 mM. Drop the dispersion of the chemotactic cationic and anionic colloidal motor prepared in Example 1 on a hydrophilic glass slide. After sealing the slide, observe and record the movement behavior of the motor and calculate the diffusion coefficient under bright field using an inverted optical microscope. As Figure 7 shown, in the H2O2-driven Pt-CBD / MSN@CS colloidal motor system, as the concentration of H2O2 increases, the diffusion coefficient increases from 0.61 μm / s 2 to 1.43 μm / s 2 .

[0113] Establish a horizontal Y-shaped channel, as Figure 8As shown, after establishing an in vitro cell model with normal chondrocytes and inflammatory cells formed by IL-1β stimulation, the chemotactic amphiphilic colloidal motor prepared in Example 1 was added to chamber i, and the fluorescence intensities of chambers ii and iii were recorded simultaneously. After 1.5 h, the fluorescence intensity in the chondrocyte chamber treated with IL-1β was significantly higher than that in the chondrocyte chamber, indicating that the chemotactic amphiphilic colloidal motor tended to move towards inflammatory cells, demonstrating the positive chemotactic movement of the motor in the simulated cell inflammatory environment.

Claims

1. A chemotactic yin-yang type colloidal motor, characterized in that The colloidal motor uses mesoporous silica nanoparticles as a drug carrier, loads the hydrophobic drug cannabidiol, and constructs a Janus structure by surface coating with a pH-responsive chitosan layer and unilateral deposition of a platinum catalytic layer.

2. The chemotactic yin-yang type colloidal motor according to claim 1, characterized in that The mesoporous silica nanoparticles have a particle size of 400 - 900 nm and a pore size of 2 - 3 nm.

3. The chemotactic yin-yang type colloidal motor according to claim 1, characterized in that The deposition thickness of the platinum catalytic layer is 8 - 12 nm.

4. A method for preparing the chemotactic yin-yang type colloidal motor according to any one of claims 1-3, characterized in that The method includes the following steps: Step (1) Preparation of mesoporous silica nanoparticles: Silica nanoparticles are prepared by the sol-gel method, and a mesoporous structure is formed after high-temperature calcination to obtain mesoporous silica nanoparticles, where:; Step (2) Loading the lipophilic drug CBD: The mesoporous silica nanoparticles prepared in step (1) are mixed with a CBD-ethanol solution in a mass ratio of 1:50 - 1:10, and drug-loaded nanoparticles are obtained by electrostatic adsorption. Step (3) Coating with a pH-responsive chitosan layer: The drug-loaded nanoparticles prepared in step (2) are uniformly dispersed in a chitosan-acetic acid solution, and the chitosan layer is coated by magnetic stirring to achieve pH-dependent drug release. Step (4) Preparation of an asymmetric colloidal motor: A platinum catalytic layer is vacuum sputtered on one side of the particles prepared in step (3) by chemical vapor deposition to construct an asymmetric platinum catalytic layer to form a Janus structure and endow self-propelling ability.

5. The preparation method of the chemotactic yin-yang type colloidal motor according to claim 4, characterized in that The high-temperature calcination temperature is 500 - 600 °C, and the calcination time is 5 - 7 h.

6. The preparation method of the chemotactic yin-yang type colloidal motor according to claim 4, characterized in that The concentration of the CBD-ethanol solution is 0.01 - 0.1 mg / mL.

7. The preparation method of the chemotactic yin-yang type colloidal motor according to claim 4, wherein The concentration of the chitosan-acetic acid solution is 0.4 - 0.8% w / v.

8. The preparation method of the chemotactic yin-yang type colloidal motor according to claim 4, characterized in that The intensity of the vacuum sputtering is 13 - 16 mA, and the time is 200 - 250 s.

9. Use of the chemotactic cationic and anionic colloidal motor according to any one of claims 1 - 3 in targeted inflammation therapy.

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