A drug-loaded halloysite nanotube and its preparation method

Abstract

A drug-loaded halloysite nanotube, comprising halloysite nanotubes, a phase change material, a drug and a photothermal conversion material, wherein the photothermal conversion material is an organic photosensitizer or a two-dimensional photothermal conversion material. Under near-infrared light irradiation, the photothermal conversion material converts light energy into heat energy, causing the temperature inside the halloysite nanotubes to rise. The phase change material undergoes a solid-liquid transformation, so that the drug can diffuse out, thereby realizing the controlled release of the drug by the halloysite nanotubes under near-infrared light.

Description

Technical Field

[0001] The present invention belongs to the field of biomaterials, and particularly relates to a halloysite nanotube loaded with a drug and a preparation method thereof. Background Art

[0002] Traditional drug delivery systems usually rely on passive diffusion or polymer degradation to control release. Although these delivery methods can achieve local drug release, they are not suitable for spatio-temporal release. As an alternative, "intelligent" material release systems based on materials that can be activated by external stimuli (such as temperature, light, magnetic field, electric field or ultrasound) have immediate advantages in spatio-temporal control.

[0003] Near-infrared (NIR) light has received extensive attention due to its deep penetration into soft tissues and high spatio-temporal precision. Near-infrared light has been applied to a series of biological studies, including the light regulation of CRISPR / Cas9 gene editing, the directional photothermal activation of neurons, the photoactivation of protein channels for cancer treatment, and the elimination of bacteria through synergistic chemo-photothermal killing, as well as promoting tissue regeneration, such as bone regeneration and wound healing.

[0004] Phase change materials (PCMs) are a new type of thermosensitive material that can undergo reversible solid-liquid phase transitions according to different temperatures. Among various phase change materials, natural fatty acids are widely used due to their advantages such as low cost, high stability, biocompatibility and biodegradability. Their transition temperature is roughly similar to the human body temperature, and drugs can be loaded under conditions such as photothermal or ultrasonic heating.

[0005] In current common drug-loading studies, most are simple drug loading on halloysite nanotubes, enabling drug release through simple diffusion, which cannot achieve controllable drug release, and the release rate is very fast, making it difficult to achieve long-term continuous release. Therefore, the ability of drugs to be continuously released needs to be improved, and at the same time, achieving controllable release near the human body temperature is also a problem that needs to be solved. Summary of the Invention

[0006] One of the purposes of the present invention is to solve the problem of weak control ability of existing drug-loading materials for drugs. By providing a halloysite nanotube loaded with a drug, continuous and controllable drug release under near-infrared light control is achieved.

[0007] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0008] A halloysite nanotube loaded with a drug, comprising a halloysite nanotube, a phase change material (PCM), a drug and a photothermal conversion material, wherein the photothermal conversion material is an organic photosensitizer or a two-dimensional photothermal conversion material.

[0009] In the above technical solution, based on 100 parts by weight of the halloysite nanotubes, it includes 300 - 1500 parts of the phase change material, preferably 625 - 1250 parts; it includes 100 - 1000 parts of the drug, preferably 300 - 800 parts of the drug; it includes 1 - 10 parts of the photothermal conversion material, preferably 3 - 4 parts.

[0010] In the above technical solution, the halloysite nanotubes are halloysite nanotubes modified by 3-aminopropyltriethoxysilane (silane coupling agent KH-550). The halloysite nanotubes modified by KH-550 have increased solubility in organic solvents.

[0011] In the above technical solution, the phase change material includes lauric acid and stearic acid, preferably a mixture of lauric acid and stearic acid, and the mixing ratio is (3 - 5):1, further preferably 4:1. The phase change material with the above preferred ratio can achieve solid-liquid transformation at 39°C, and this temperature is similar to the human body temperature and will not cause other side effects to the human body.

[0012] In the above technical solution, the organic photosensitizer is at least one of indocyanine green and prussian blue, preferably indocyanine green. Indocyanine green is an organic photosensitive reagent approved by the US Food and Drug Administration (FDA) for clinical application, and it is an excellent tissue penetrant that can effectively convert light energy into heat energy, thus realizing the function of photothermal conversion.

[0013] In the above technical solution, the two-dimensional photothermal conversion material is at least one of black phosphorus, MXene, graphene, and graphene oxide materials, preferably black phosphorus. Black phosphorus has good light absorption and photothermal conversion efficiency, good biocompatibility, and its degradation product is phosphate beneficial to the human body, without long-term biological toxicity.

[0014] In the above technical solution, the drug is an antibacterial drug, an anti-inflammatory drug, or an analgesic drug. Preferably, the drug is selected from but not limited to penicillins, cephalosporins, tetracyclines, chloramphenicols, macrolides, lincomycins, nitroimidazoles, antibacterial polypeptides, and anti-inflammatory and analgesic drugs such as aspirin, paracetamol, indomethacin zinc, naproxen, diclofenac, ibuprofen, etc.

[0015] In the above technical solution, the drug-loaded halloysite nanotubes release the drug under near-infrared photothermal conditions.

[0016] The second object of the present invention is to provide a preparation method of drug-loaded halloysite nanotubes to solve the problem that the drug release in the current drug-loading material is too fast and the spatio-temporal loading cannot be achieved.

[0017] To achieve the above object, the present invention is realized through the following technical solutions:

[0018] A preparation method of drug-loaded halloysite nanotubes: First, disperse the halloysite nanotubes, then add the drug, and then add the dissolved photothermal conversion material. Finally, wash, resuspend, and centrifuge to obtain the product.

[0019] Preferably, the above preparation method includes the following steps:

[0020] (1) Modification of halloysite nanotubes: Dissolve 3-aminopropyltriethoxysilane (APTES) in toluene, add halloysite nanotube powder, and ultrasonically disperse for 20 - 30 min. Reflux the above suspension under constant stirring at 110 - 130 °C for 20 - 22 h. Wash the resulting mixture with toluene 5 - 8 times to remove the excess organosilane, and then dry it overnight at 110 - 130 °C to further cure. Then wash the mixture with deionized water 5 - 6 times, and then freeze-dry the sample overnight.

[0021] (2) Prepare the phase change material (PCM) by simply physically mixing lauric acid (LA) and stearic acid (SA).

[0022] (3) Take the above-modified halloysite nanotubes and PCM and dissolve them in dimethyl sulfoxide (DMSO) solution, and ultrasonically treat the flask containing the above solution for 15 - 25 min.

[0023] (4) Further, add the drug to the beaker after the above ultrasonic treatment, and ultrasonically treat for 25 - 35 min. During the ultrasonic treatment, maintain the temperature at 25 °C - 30 °C.

[0024] (5) Further, dissolve the photosensitizer or photothermal conversion material in dimethyl sulfoxide (DMSO) solution. Then add the dissolved ICG solution to the above ultrasonically treated flask, and continue to ultrasonically treat for 5 - 8 min, with the temperature controlled at 25 - 30 °C.

[0025] (6) Vacuum the above dissolved solution with a vacuum pump for 10 - 20 min, then open the piston above the beaker to release gas for 5 - 10 min, and repeat the above operations 4 - 8 times.

[0026] (7) Further, wash, resuspend, and centrifuge using DMSO solvent. Repeat this process twice, and finally remove the upper layer of liquid.

[0027] (8) Finally, wash with deionized water, resuspend, and centrifuge multiple times until the upper layer of liquid is clear and there is no turbidity.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] Through photothermal triggering, the ability of halloysite nanotubes loaded with drugs to release drugs is achieved. Phase change materials (PCMs), drugs, and organic photosensitizers or two-dimensional photothermal conversion materials are loaded inside the halloysite nanotubes, and the PCM simultaneously wraps the drugs and organic photosensitizers or two-dimensional photothermal conversion materials. Under near-infrared light irradiation, the organic photosensitizers or two-dimensional photothermal conversion materials convert light energy into heat energy, causing the temperature inside the halloysite nanotubes to rise. The PCM undergoes a solid-liquid transition, so the drugs can diffuse out, thus realizing the controlled release of drugs by halloysite nanotubes under near-infrared light. Description of the Drawings

[0030] Figure 1 Figure 6 is a scanning electron microscope image of halloysite nanotubes modified with 3-aminopropyltriethoxysilane (APTES);

[0031] Figure 2 Figure 10 is a scanning electron microscope image of the halloysite nanotubes modified in Example 1 loaded with phase change material-coated indocyanine green and rifampicin;

[0032] Figure 3 Figure 14 is a scanning electron microscope image of the halloysite nanotubes loaded with phase change material-coated indocyanine green and rifampicin after being irradiated with near-infrared light in Example 1;

[0033] Figure 4 Figure 18 is a thermogravimetric loss percentage graph of the halloysite nanotubes loaded with rifampicin in Example 1;

[0034] Figure 5 Figure 22 is a release curve graph of rifampicin from the modified halloysite nanotubes loaded with phase change material and indocyanine green with and without near-infrared light irradiation in Example 1. Detailed Embodiments

[0035] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the content of the present invention still fall within the protection scope of the present invention.

[0036] Sources of the raw materials used:

[0037] Halloysite nanotubes (Guangzhou Runwo Material Technology Co., Ltd.), indocyanine green (Auneji Chemical Technology Co., Ltd.), stearic acid (Sigma), lauric acid (Sigma), silane coupling agent KH-550 (Alfa Aesar), and other conventional reagents are all commercially available.

[0038] Example 1

[0039] 1. Dissolve 500 μL of 3-aminopropyltriethoxysilane (APTES) in 6.25 mL of toluene, add 0.15 g of halloysite nanotube powder, and ultrasonically disperse for 30 min.

[0040] 2. Reflux the above suspension under constant stirring at 120 °C for 20 h. Wash the resulting mixture 6 times with toluene to remove the excess organic alkane, and then dry it overnight at 120 °C to further cure. Then wash the mixture 5 times with deionized water, and then freeze-dry the sample overnight.

[0041] 3. Prepare the phase change material (PCM) by simply physically mixing lauric acid (LA) and stearic acid (SA) with a mass ratio of 4:1.

[0042] 4. Further, take 240 mg of the above-modified halloysite nanotubes and 1500 mg of PCM and dissolve them in 5 mL of dimethyl sulfoxide (DMSO) solution, and ultrasonically treat the flask containing the above solution for 25 min.

[0043] 5. Further, add 600 mg of rifampicin (RFP) to the beaker after the above ultrasonic treatment, and ultrasonically treat for 30 min. During the ultrasonic treatment, maintain the temperature at 25 °C to 30 °C.

[0044] 6. Further, dissolve 7.5 mg of indocyanine green (ICG) in 1 mL of dimethyl sulfoxide (DMSO) solution. During this process, pay attention to covering the small beaker containing the ICG solution with tin foil to avoid ICG from seeing light. Then add the dissolved ICG solution to the above ultrasonically treated flask, cover it with tin foil again after adding, and continue to ultrasonically treat for 5 min, with the temperature controlled at 25 - 30 °C.

[0045] 7. Vacuum the above dissolved solution with a vacuum pump for 15 min, then open the piston above the beaker to release gas for 5 min, and repeat the above operations 5 times.

[0046] 8. Further, transfer the solution after evacuation and gas release into centrifuge tubes. After equal division, the solution in each centrifuge tube is 1 mL / tube. Then add 6 mL of DMSO solvent to the centrifuge tubes. Repeatedly pipette and wash with a 1000 μL pipette gun, and centrifuge the pipetted solution. After centrifugation, remove the upper layer solution. Repeat the centrifugation operation twice in this process. Set the temperature of the centrifuge at 25 °C, the rotation speed at 4000 rpm, and centrifuge for 5 min.

[0047] 9. Finally, wash with deionized water. Use a 1000 μL pipette to repeatedly blow and beat the above solution, and then centrifuge it with a centrifuge to remove the upper liquid. The temperature of the centrifuge is set at 10 °C, the rotation speed is 4000 rpm, and centrifuge for 3 minutes. Repeat the above operations multiple times until the upper liquid is clear and there is no turbidity.

[0048] Example 2

[0049] 1. Dissolve 500 μL of 3-aminopropyltriethoxysilane (APTES) in 6.25 mL of toluene, add 0.15 g of halloysite nanotube powder, and ultrasonically disperse for 30 min.

[0050] 2. Reflux the above suspension under constant stirring at 120 °C for 20 h. Wash the resulting mixture 6 times with toluene to remove excess silane, and then dry it overnight at 120 °C to further cure. Then wash the mixture 6 times with deionized water, and then freeze-dry the sample overnight.

[0051] 3. Prepare a phase change material (PCM) by simply physically mixing lauric acid (LA) and stearic acid (SA) with a mass ratio of 4:1.

[0052] 4. Further, take 240 mg of the above-modified halloysite nanotubes and 1200 mg of PCM and dissolve them in 5 mL of dimethyl sulfoxide (DMSO) solution, and ultrasonically irradiate the flask containing the above solution for 25 min.

[0053] 5. Further, add 500 mg of the antibiotic metronidazole (MAN) to the above beaker after ultrasonic irradiation, and ultrasonically irradiate for 30 min. During the ultrasonic irradiation process, maintain the temperature at 25 °C to 30 °C.

[0054] 6. Further, dissolve 8 mg of indocyanine green (ICG) in 1 mL of dimethyl sulfoxide (DMSO) solution. During this process, pay attention to covering the small beaker containing the ICG solution with tin foil to avoid ICG from seeing light. Then add the dissolved ICG solution to the above ultrasonically irradiated flask, cover it with tin foil again after adding, and continue to ultrasonically irradiate for 5 min, with the temperature controlled at 25 - 30 °C.

[0055] 7. Evacuate the above dissolved solution with a vacuum pump for 20 min, and then open the piston above the beaker to release gas for 8 min. Repeat the above operations 8 times.

[0056] 8. Further, the solution after gas drainage is introduced into a centrifuge tube. After equal distribution, the solution in each centrifuge tube is 1 mL / tube. Then, 6 mL of DMSO solvent is added to the centrifuge tube. The solution is repeatedly pipetted and washed with a 1000 μL pipette gun. The pipetted solution is centrifuged using a centrifuge. After centrifugation, the upper layer solution is removed. This centrifugation operation is repeated twice. The temperature of the centrifuge is set at 25 °C, the rotation speed is 4000 rpm, and the centrifugation time is 5 min.

[0057] 9. Finally, it is washed with deionized water. The above solution is repeatedly pipetted with a 1000 μL pipette gun and then centrifuged using a centrifuge to remove the upper layer liquid. The temperature of the centrifuge is set at 10 °C, the rotation speed is 4000 rpm, and the centrifugation time is 3 minutes. The above operations are repeated multiple times until the upper layer liquid is clear and there is no turbidity.

[0058] Example 3

[0059] 1. Dissolve 500 μL of 3-aminopropyltriethoxysilane (APTES) in 6.25 mL of toluene, add 0.15 g of halloysite nanotube powder, and ultrasonically disperse for 30 min.

[0060] 2. The above suspension is refluxed under constant stirring at 120 °C for 20 h. The resulting mixture is washed 6 times with toluene to remove the excess silane, and then dried overnight at 120 °C for further curing. Then the mixture is washed 10 times with deionized water, and then the sample is freeze-dried overnight.

[0061] 3. The phase change material (PCM) is prepared by simply physically mixing lauric acid (LA) and stearic acid (SA) with a mass ratio of 4:1.

[0062] 4. Further, take 240 mg of the above modified halloysite nanotubes and 1800 mg of PCM and dissolve them in 5 mL of dimethyl sulfoxide (DMSO) solution. The flask containing the above solution is ultrasonically treated for 20 min.

[0063] 5. Further, add 300 mg of aspirin (ASA) to the above ultrasonicated beaker and ultrasonically treat for 30 min. During the ultrasonic treatment, the temperature is maintained at 25 °C - 30 °C.

[0064] 6. Further, add 6 mg of black phosphorus to 1 mL of dimethyl sulfoxide (DMSO) solution for dispersion. Then the dispersed black phosphorus solution is added to the above ultrasonicated flask. After addition, it is wrapped with tin foil again and ultrasonically treated for 6 min, and the temperature is controlled at 25 - 30 °C.

[0065] 7. Vacuum the above-dissolved solution with a vacuum pump for 20 min, then open the piston above the beaker to release the air for 5 min. Repeat the above operations 6 times.

[0066] 8. Further, transfer the solution after evacuation and gas release into centrifuge tubes. After equal distribution, the solution in each centrifuge tube is 1 mL / tube. Then add 6 mL of DMSO solvent to the centrifuge tubes. Use a 1000 μL pipette to blow and wash repeatedly, and centrifuge the blown solution with a centrifuge. After centrifugation, remove the upper layer solution. Repeat this centrifugation operation twice. The temperature of the centrifuge is set at 25 °C, the rotation speed is 4000 rpm, and centrifuge for 5 min.

[0067] 9. Finally, wash with deionized water. Use a 1000 μL pipette to blow the above solution repeatedly, then centrifuge with a centrifuge to remove the upper layer liquid. The temperature of the centrifuge is set at 10 °C, the rotation speed is 4000 rpm, and centrifuge for 3 minutes. Repeat the above operations multiple times until the upper layer liquid is clear and free of turbidity.

[0068] Example 4

[0069] 1. Dissolve 500 μL of 3-aminopropyltriethoxysilane (APTES) in 6.25 mL of toluene, add 0.15 g of halloysite nanotube powder, and ultrasonically disperse for 28 min.

[0070] 2. Reflux the above suspension under constant stirring at 120 °C for 22 h. Wash the resulting mixture with toluene 6 times to remove excess silane, then dry it at 120 °C overnight for further curing. Then wash the mixture with deionized water 6 times, and then freeze-dry the sample overnight.

[0071] 3. Simply physically mix lauric acid (LA) and stearic acid (SA) with a mass ratio of 4:1 to prepare a phase change material (PCM).

[0072] 4. Further, take 200 mg of the above-modified halloysite nanotubes and 1500 mg of PCM and dissolve them in 5 mL of dimethyl sulfoxide (DMSO) solution, and ultrasonically irradiate the flask containing the above solution for 20 min.

[0073] 5. Further, add 600 mg of ibuprofen (APC) to the beaker after the above ultrasonic treatment, and ultrasonically irradiate for 30 min. During the ultrasonic process, maintain the temperature at 25 °C to 30 °C.

[0074] 6. Further, 7.5 mg of indocyanine green (ICG) was added to 1 mL of dimethyl sulfoxide (DMSO) solution for dissolution. During this process, note that the small beaker containing the ICG solution was wrapped with tin foil to avoid ICG from being exposed to light. Then the dissolved ICG solution was added to the above-mentioned ultrasonically treated flask, and after addition, it was wrapped with tin foil again and ultrasonicated for another 8 min, with the temperature controlled at 25 - 30 °C.

[0075] 7. The above-mentioned dissolved solution was evacuated using a vacuum pump for 18 min, and then the piston above the beaker was opened to release air for 6 min. The above operations were repeated 5 times.

[0076] 8. Further, the solution after evacuation and air release was introduced into a centrifuge tube. After equal division, the solution in each centrifuge tube was 1 mL / tube. Then 6 mL of DMSO solvent was added to the centrifuge tube. It was repeatedly pipetted and washed with a 1000 μL pipette gun, and the pipetted solution was centrifuged using a centrifuge. After centrifugation, the upper layer solution was removed. This centrifugation operation was repeated twice. The temperature of the centrifuge was set at 25 °C, the rotation speed was 4000 rpm, and the centrifugation time was 5 min.

[0077] 9. Finally, it was washed with deionized water. The above solution was repeatedly pipetted with a 1000 μL pipette gun and then centrifuged using a centrifuge to remove the upper layer liquid. The temperature of the centrifuge was set at 10 °C, the rotation speed was 4000 rpm, and the centrifugation time was 3 minutes. The above operations were repeated multiple times until the upper layer liquid was clear and there was no turbidity.

[0078] The performance test results of the drug-loaded halloysite nanotubes in Examples 1 - 4 of the present invention are as follows: The drug-loaded halloysite nanotubes were evacuated and air released, enabling the loading of PCM, drug, and photothermal conversion material into the halloysite nanotubes; Figure 5 Among them, the effects of turning on (on) and turning off (off) infrared light on drug release are shown. It can be seen that without irradiating near-infrared light, the drug was continuously released and it was difficult to control its release rate. Under the irradiation of near-infrared light, rapid and controllable drug release was achieved.

[0079] Comparative Example 1

[0080] Example 4 of CN104524643A was used as Comparative Example 1. In the comparative example, the antibacterial drug metronidazole was simply mixed and loaded into halloysite nanotubes, and then the drug-loaded halloysite nanotubes were loaded into an electrospinning solution for co-blending electrospinning. As can be seen from the example table, drug release started continuously from the beginning, and it took about 25 hours to release 100%. Compared with the present invention, under near-infrared light irradiation, the PCM undergoes a phase change from a liquid state to a solid state, and the drug is rapidly released. When the near-infrared light is turned off, the PCM turns into a solid state and the drug is slowly released. Therefore, the prominent advantage of the present invention is that controllable release under near-infrared light irradiation can be achieved.

[0081] The above-described embodiments are only a preferred solution of the present invention, and do not impose any form of limitation on the present invention. There are other variations and modifications without exceeding the technical solutions recorded in the claims.

Claims

1. A drug-loaded halloysite nanotube, comprising halloysite nanotubes, a phase change material, a drug, and a photothermal conversion material, wherein, the photothermal conversion material is an organic photosensitizer or a two-dimensional photothermal conversion material; taking the weight of the halloysite nanotubes as 100 parts, it includes 300 to 1500 parts of the phase change material, 100 to 1000 parts of the drug, and 1 to 10 parts of the photothermal conversion material; the halloysite nanotubes are 3-aminopropyltriethoxysilane-modified halloysite nanotubes; the phase change material is a mixture of lauric acid and stearic acid, and the mixing ratio is (3 to 5):1; the organic photosensitizer is at least one of indocyanine green and prussian blue; the two-dimensional photothermal conversion material is at least one of black phosphorus, MXene, graphene, and graphene oxide materials.

2. The drug-loaded halloysite nanotube according to claim 1, characterized in that: taking the weight of the halloysite nanotubes as 100 parts, it includes 625 to 1250 parts of the phase change material; 300 to 800 parts of the drug; 3 to 4 parts of the photothermal conversion material.

3. The drug-loaded halloysite nanotube according to claim 1 or 2, characterized in that: the mixing ratio of the lauric acid and stearic acid is 4:

1.

4. The drug-loaded halloysite nanotube according to claim 1 or 2, characterized in that: the organic photosensitizer is indocyanine green.

5. The drug-loaded halloysite nanotube according to claim 1 or 2, characterized in that: the two-dimensional photothermal conversion material is black phosphorus.

6. The drug-loaded halloysite nanotube according to claim 1 or 2, characterized in that: the drug is an antibacterial drug, an anti-inflammatory drug, or an analgesic.

7. The drug-loaded halloysite nanotube according to claim 1 or 2, characterized in that: the drug-loaded halloysite nanotube realizes the release of the drug under near-infrared photothermal conditions.

8. A preparation method of the drug-loaded halloysite nanotube according to any one of claims 1 to 7: First, disperse the halloysite nanotubes, then add the drug, then add the dissolved photothermal conversion material, and finally wash, resuspend, and centrifuge to obtain the product.

9. The preparation method according to claim 8, characterized in that: the reaction is carried out under ultrasound, and the reaction temperature is 25°C to 30°C.

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