阅读说明：本技术 一种具有抗肿瘤功能的纳米机器人及其制备方法 (Nano robot with anti-tumor function and preparation method thereof ) 是由 不公告发明人 于 2020-11-10 设计创作，主要内容包括：本发明属于纳米材料领域,尤其涉及一种具有抗肿瘤功能的纳米机器人及其制备方法。本发明提供的制备方法包括以下步骤：a)将磁性镁合金纳米颗粒、抗肿瘤药物、聚乳酸和挥发性有机溶剂混合,得到混合液；b)将所述混合液与水混合并搅拌挥去混合体系中的挥发性有机溶剂,得到混悬液；c)对所述混悬液进行离心分离,弃上清液,得到具有抗肿瘤功能的纳米机器人。本发明提供的制备方法生产工艺稳定,采用该方法制备得到的纳米机器人具有良好尺寸均匀性、可降解性和药物缓释效果,且可在外加磁场控制下准确到达肿瘤部位,实现对肿瘤的靶向治疗。(The invention belongs to the field of nano materials, and particularly relates to a nano robot with an anti-tumor function and a preparation method thereof. The preparation method provided by the invention comprises the following steps: a) mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug, polylactic acid and a volatile organic solvent to obtain a mixed solution; b) mixing the mixed solution with water, stirring and volatilizing the volatile organic solvent in the mixed system to obtain a suspension; c) and carrying out centrifugal separation on the suspension, and discarding the supernatant to obtain the nano robot with the anti-tumor function. The preparation method provided by the invention has stable production process, and the nano robot prepared by the method has good size uniformity, degradability and drug slow-release effect, can accurately reach the tumor part under the control of an external magnetic field, and realizes the targeted therapy of the tumor.)

1. A preparation method of a nano robot with an anti-tumor function comprises the following steps:

a) mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug, polylactic acid and a volatile organic solvent to obtain a mixed solution;

b) mixing the mixed solution with water, stirring and volatilizing the volatile organic solvent in the mixed system to obtain a suspension;

c) and carrying out centrifugal separation on the suspension, and discarding the supernatant to obtain the nano robot with the anti-tumor function.

2. The preparation method according to claim 1, wherein in the step a), the chemical composition of the magnetic magnesium alloy particles comprises Nd, Fe and SiO₂Mn, Zn and Mg.

3. The method according to claim 1, wherein in the step a), the magnetic magnesium alloy particles are prepared by the following steps:

i) coating a gelatin solution on the surface of the substrate to form a gelatin film layer;

ii) screen printing the gelatin film layer to form a plurality of convex columns on the gelatin film layer;

iii) plating a magnesium alloy magnetic material on the gelatin film layer formed with the convex column to form a magnesium alloy magnetic film layer;

iv) heating the multilayer composite material obtained in the step iii) in water until a gelatin film layer in the material is dissolved, and separating the magnesium alloy magnetic film layer from the substrate;

v) grinding the magnesium alloy magnetic film layer obtained by separation in the step iv) to obtain magnetic magnesium alloy particles.

4. The preparation method according to claim 1, wherein in the step a), the magnetic magnesium alloy nanoparticles are pretreated before being mixed; the pretreatment comprises the following specific steps:

and soaking the magnetic magnesium alloy nanoparticles in a sodium heparin aqueous solution, and taking out and air-drying the magnetic magnesium alloy nanoparticles.

5. The preparation method according to claim 1, wherein the antitumor drug in step a) comprises one or more of paclitaxel, dexamethasone, frogavidin, doxorubicin, docetaxel and doxorubicin.

6. The method according to claim 1, wherein the polylactic acid has a number average molecular weight of 5000 to 50000 in step a).

7. The preparation method according to claim 1, wherein in the step a), the mass ratio of the magnetic magnesium alloy nanoparticles to the antitumor drug to the polylactic acid is 1: (1-3): (2-5).

8. The method according to claim 1, wherein in step b), the suspension further comprises a nonionic surfactant and/or folic acid.

9. The method of claim 8, wherein the non-ionic surfactant comprises one or more of tween80, tween 20, and a poloxamer.

10. The nano robot with the anti-tumor function prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention belongs to the field of nano materials, and particularly relates to a nano robot with an anti-tumor function and a preparation method thereof.

Background

Tumor tissue is actually a complete ecosystem formed by tumor cells and tumor blood vessels, and contains not only tumor cells but also abundant tumor blood vessels inside. Modern biomedical research has demonstrated that tumor vessels are structurally very different from normal vessels. In general, normal blood vessels take a year to grow and are three-layer compact structures consisting of intima, media and adventitia, whereas tumor vessels can be formed in only 4 days and are structurally single-layer thin films consisting of endothelial cells. However, because the endothelial cells constituting the tumor vessels have large gaps and incomplete structures, the tumor vessels usually contain a large number of small pores with nanometer scale, so that small molecules and some nanoparticles can penetrate through the pores.

At present, many research institutes have developed novel tumor treatment schemes by utilizing the high permeability of tumor vessels to small molecules and nanoparticles, for example, a nano robot with an anti-tumor function is used for treating tumors, and the nano robot with the anti-tumor function refers to nanoparticles loaded with anti-tumor drugs. Research shows that the drug-loaded nano robot can effectively enrich the inside of a tumor after being injected into a human body by utilizing the high permeability of tumor blood vessels to nano particles, so that a good tumor treatment effect is obtained.

At present, most of the research on the field of tumor treatment by the nano-robot with the anti-tumor function is still in the experimental stage, and the problems of poor stability of the preparation process, poor size uniformity of products, poor degradability, poor tumor treatment effect and the like of the nano-robot exist, so that the application of the nano-robot in the field of tumor treatment is seriously influenced.

Disclosure of Invention

In view of the above, the present invention aims to provide a nano robot with an anti-tumor function and a preparation method thereof, the preparation method provided by the present invention has a stable production process, and the nano robot prepared by the method has good size uniformity, degradability and drug slow-release effect, and can accurately reach a tumor part under the control of an external magnetic field, so as to realize targeted therapy on tumors.

The invention provides a preparation method of a nano robot with an anti-tumor function, which comprises the following steps:

a) mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug, polylactic acid and a volatile organic solvent to obtain a mixed solution;

b) mixing the mixed solution with water, stirring and volatilizing the volatile organic solvent in the mixed system to obtain a suspension;

c) and carrying out centrifugal separation on the suspension, and discarding the supernatant to obtain the nano robot with the anti-tumor function.

Preferably, in step a), the chemical composition of the magnetic magnesium alloy particles comprises Nd, Fe and SiO₂Mn, Zn and Mg.

Preferably, in step a), the magnetic magnesium alloy particles are prepared according to the following steps:

i) coating a gelatin solution on the surface of the substrate to form a gelatin film layer;

ii) screen printing the gelatin film layer to form a plurality of convex columns on the gelatin film layer;

iii) plating a magnesium alloy magnetic material on the gelatin film layer formed with the convex column to form a magnesium alloy magnetic film layer;

iv) heating the multilayer composite material obtained in the step iii) in water until a gelatin film layer in the material is dissolved, and separating the magnesium alloy magnetic film layer from the substrate;

v) grinding the magnesium alloy magnetic film layer obtained by separation in the step iv) to obtain magnetic magnesium alloy particles.

Preferably, in the step a), the magnetic magnesium alloy nanoparticles are pretreated before being mixed; the pretreatment comprises the following specific steps:

and soaking the magnetic magnesium alloy nanoparticles in a sodium heparin aqueous solution, and taking out and air-drying the magnetic magnesium alloy nanoparticles.

Preferably, in step a), the anti-tumor drug comprises one or more of paclitaxel, dexamethasone, frogspawn, doxorubicin, docetaxel and doxorubicin.

Preferably, in the step a), the number average molecular weight of the polylactic acid is 5000-50000.

Preferably, in the step a), the mass ratio of the magnetic magnesium alloy nanoparticles to the antitumor drug to the polylactic acid is 1: (1-3): (2-5).

Preferably, in step b), the suspension further comprises a nonionic surfactant and/or folic acid.

Preferably, the non-ionic surfactant comprises one or more of tween80, tween 20 and a poloxamer.

The invention provides a nano robot with an anti-tumor function, which is prepared by the preparation method according to the technical scheme.

Compared with the prior art, the invention provides a nano robot with an anti-tumor function and a preparation method thereof. The preparation method provided by the invention comprises the following steps: a) mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug, polylactic acid and a volatile organic solvent to obtain a mixed solution; b) mixing the mixed solution with water, stirring and volatilizing the volatile organic solvent in the mixed system to obtain a suspension; c) and carrying out centrifugal separation on the suspension, and discarding the supernatant to obtain the nano robot with the anti-tumor function. Firstly, uniformly mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug and polylactic acid in a volatile organic solvent; then mixing the suspension with water and stirring to volatilize the volatile organic solvent to obtain a suspension; finally, insoluble substances in the suspension are separated out in a centrifugal separation mode, and the nano robot with the anti-tumor function is obtained. According to the preparation method provided by the invention, the magnetic magnesium alloy nanoparticles are added into the nano robot, so that on one hand, the nano robot can show good magnetism, and can accurately reach a tumor part under the control of an external magnetic field, and the targeted therapy of the tumor is realized; on the other hand, the magnetic magnesium alloy nanoparticles can be completely degraded, so that the nano robot can show good degradability. Meanwhile, the preparation method provided by the invention can regulate and control the degradation speed of the nano robot by adding the polylactic acid into the nano robot, thereby controlling the drug release speed of the nano robot to a certain extent and achieving the purposes of drug slow release and long-acting release. The nano robot prepared by the method provided by the invention has good size uniformity, magnetism, degradability, anti-tumor function and drug slow-release effect, can efficiently kill tumor cells in a targeted manner, and can be completely degraded or absorbed by a human body after killing the tumor cells without any side effect. The preparation method provided by the invention has stable and controllable production process, is suitable for industrialization, and has wide application prospect in the field of tumor treatment.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of a grid shape provided by an embodiment of the present invention, which is a circle, a regular hexagon, and a square in sequence from left to right;

FIG. 2 is a schematic diagram illustrating the operation of heating to dissolve a gelatin film layer according to an embodiment of the present invention;

fig. 3 is a partial process flow diagram for preparing a magnesium alloy drug-loaded nano robot according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of a nano robot with an anti-tumor function, which comprises the following steps:

a) mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug, polylactic acid and a volatile organic solvent to obtain a mixed solution;

b) mixing the mixed solution with water, stirring and volatilizing the volatile organic solvent in the mixed system to obtain a suspension;

c) and carrying out centrifugal separation on the suspension, and discarding the supernatant to obtain the nano robot with the anti-tumor function.

In the preparation method provided by the invention, magnetic magnesium alloy nanoparticles are provided firstly. Wherein the chemical composition of the magnetic magnesium alloy particles preferably comprises Nd, Fe and SiO₂Mn, Zn and Mg; the content of Nd in the magnetic magnesium alloy particles is preferably 3-5 wt%, and specifically can be 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%; the content of Fe in the magnetic magnesium alloy particles is preferably 3-5 wt%, and specifically can be 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%; the SiO₂The content in the magnetic magnesium alloy particles is preferably 10 to 15 wt%, and specifically may be 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, 12 wt%, 12.5 wt%, 13 wt%, 13.5 wt%, 14 wt%, 14.5 wt%, or 15 wt%; the content of Mn in the magnetic magnesium alloy particles is preferably 3-5 wt%, and specifically can be 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%; the content of Zn in the magnetic magnesium alloy particles is preferably 15-20 wt%, and specifically can be 15 wt%, 15.5 wt%, 16 wt%, 16.5 wt%, 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, 19 wt%, 19.5 wt% or 20 wt%; the content of Mg in the magnetic magnesium alloy particles is preferably 50 to 66 wt%, and specifically may be 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, 65 wt%, or 66 wt%. In the invention, the particle size of the magnetic magnesium alloy particle is preferably 50-200 nm, and specifically can be 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200 nm. In the present invention, the magnetic magnesium alloy particles are preferably prepared according to the following steps:

i) coating a gelatin solution on the surface of the substrate to form a gelatin film layer;

ii) screen printing the gelatin film layer to form a plurality of convex columns on the gelatin film layer;

iii) plating a magnesium alloy magnetic material on the gelatin film layer formed with the convex column to form a magnesium alloy magnetic film layer;

iv) heating the multilayer composite material obtained in the step iii) in water until a gelatin film layer in the material is dissolved, and separating the magnesium alloy magnetic film layer from the substrate;

v) grinding the magnesium alloy magnetic film layer obtained by separation in the step iv) to obtain magnetic magnesium alloy particles.

In the preparation steps of the magnetic magnesium alloy particles, firstly, a substrate base plate is provided, wherein the type of the substrate base plate can be a polyethylene terephthalate (PET) base plate, a Polyimide (PI) base plate, a Polyethylene (PE) base plate or other flexible base plates, and can also be a glass base plate; the shape of the substrate base plate can be rectangular, circular or irregular; the thickness of the substrate base plate is preferably 0.1-5 mm, more preferably 0.2-1 mm, and specifically can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1 mm.

In the preparation step of the magnetic magnesium alloy particles provided by the invention, after the substrate base plate is obtained, the surface of the substrate base plate is coated with the gelatin solution. Before the gelatin solution is coated, the surface of the substrate base plate is preferably washed and dried, so that stains on the surface of the substrate base plate are removed, and the influence of the stains on the surface of the substrate base plate on the subsequent process is avoided. In the invention, the gelatin solution is preferably prepared according to the following method:

soaking gelatin granules in water for swelling, heating to dissolve the gelatin granules, and finally mixing the gelatin granules with glycerol to obtain gelatin solution.

In the preparation method of the gelatin solution provided by the invention, the soaking and swelling time is preferably 30-60 min, and specifically can be 30min, 35min, 40min, 45min, 50min, 55min or 60 min; the heating and dissolving temperature is preferably 50-70 ℃, and specifically can be 50 ℃, 55 ℃, 60 ℃, 65 ℃ or 70 ℃; the gelatin content in the gelatin solution is preferably 15-30 wt%, and specifically can be 15 wt%, 20 wt%, 25 wt% or 30 wt%; the content of glycerol in the gelatin solution is preferably 5-15 wt%, and specifically can be 5 wt%, 10 wt% or 15 wt%.

In the step of preparing the magnetic magnesium alloy particles, the substrate is preferably coated with gelatin solution in a knife-spin coater. The scraping speed of the knife scraping spin coater is preferably 1000-1500 rpm, and specifically can be 1000rpm, 1050rpm, 1100rpm, 1150rpm, 1200rpm, 1250rpm, 1300rpm, 1350rpm, 1400rpm, 1450rpm or 1500 rpm; the rotary scraping time of the knife scraping rotary glue spreader is preferably 10-15 s, and specifically can be 10s, 11s, 12s, 13s, 14s or 15 s; the rotary scraping uniformity of the knife-scraping rotary gumming machine is preferably controlled within +/-3%.

In the preparation step of the magnetic magnesium alloy particles provided by the invention, after the substrate base plate is coated with the gelatin solution, the gelatin solution is solidified. Wherein the curing temperature is preferably 15-30 ℃, and specifically can be 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃, 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃ or 30 ℃; the curing humidity is preferably 45-55%, and specifically can be 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54% or 55%; the curing time is preferably 40-60 min, and specifically can be 40min, 45min, 50min, 55min or 60 min. After the curing is finished, a gelatin film layer is formed, wherein the thickness of the gelatin film layer is preferably 10-20 μm, and specifically 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

In the preparation step of the magnetic magnesium alloy particles, after the gelatin film layer is formed, screen printing is performed on the gelatin film layer, so that the gelatin film layer forms a plurality of convex columns. Wherein, before the screen printing, the gelatin film layer is preferably heated to be soft, and the heating temperature is preferably 35-45 ℃, and specifically can be 35 ℃, 36 ℃, 37 ℃, 38 ℃, 39 ℃, 40 ℃, 41 ℃, 42 ℃, 43 ℃, 44 ℃ or 45 ℃; the material of the screen printing plate for screen printing comprises but is not limited to one or more of stainless steel, copper, silver, gold and molybdenum; the screen printed mesh shapes include, but are not limited to, one or more of circular, oval, square, triangular, and polygonal. In an embodiment provided by the present invention, the grid shape is as shown in fig. 1, and fig. 1 is a schematic diagram of the grid shape provided by the embodiment of the present invention, which is a circle, a regular hexagon, and a square in sequence from left to right. In the invention, the printing speed of the screen printing is preferably 4-8 m/min, and specifically can be 4m/min, 4.5m/min, 5m/min, 5.5m/min, 6m/min, 6.5m/min, 7m/min or 8 m/min; the pressing gravity of the screen printing is preferably 0.2-0.6 kg, and specifically may be 0.2kg, 0.25kg, 0.3kg, 0.35kg, 0.4kg, 0.45kg, 0.5kg, 0.55kg or 0.6 kg. And after the screen printing is finished, cooling and shaping to obtain the patterned gelatin film layer. Wherein the temperature of the temperature reduction is preferably less than or equal to 20 ℃.

In the preparation step of the magnetic magnesium alloy particles provided by the invention, after screen printing is completed, a magnesium alloy magnetic material is plated on the gelatin film layer on which the convex columns are formed. The mode for plating the magnesium alloy magnetic material is preferably magnetron sputtering; the sputtering rate of the magnetron sputtering is preferably 5-10 nm/s, and specifically can be 5nm/s, 5.5nm/s, 6nm/s, 6.5nm/s, 7nm/s, 7.5nm/s, 8nm/s, 8.5nm/s, 9nm/s, 9.5nm/s or 10 nm/s; the magnetron sputtering time is preferably 40-120 s, and specifically can be 40s, 45s, 50s, 55s, 60s, 65s, 70s, 75s, 80s, 85s, 90s, 95s, 100s, 105s, 110s, 115s or 120 s; the degree of vacuum of the magnetron sputtering is preferably 5X 10^-4～3×10^-4Pa, specifically 5X 10^-4Pa、4.5×10^-4Pa、4×10^-4Pa、3.5×10^-4Pa or 3X 10^-4Pa; the temperature of the substrate for magnetron sputtering is preferably 80-100 ℃, and specifically can be 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃; the magnetron sputtering power is preferably 3000-5000W, and specifically 3000W,3300W, 3500W, 4000W, 4500W or 5000W. In the present invention, the magnesium alloy target used in the magnetron sputtering is preferably prepared according to the following steps: I) carrying out solution treatment on the magnetic magnesium alloy to obtain a magnetic magnesium alloy solution; II) casting the magnesium alloy melt into a mould, cooling and extruding to obtain the magnesium alloy target. In the step I), the temperature of the solution treatment is preferably 700-800 ℃, and specifically can be 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃ or 800 ℃; the time of the solution treatment is preferably 7-8 h, and specifically can be 7h, 7.1h, 7.2h, 7.3h, 7.4h, 7.5h, 7.6h, 7.7h, 7.8h, 7.9h or 8 h; in the step II), during casting, the temperature of the magnetic magnesium alloy melt is preferably 200-300 ℃, and specifically can be 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃ or 300 ℃; in the step II), when casting is carried out, the temperature of the mould is preferably 150-250 ℃, and specifically can be 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃ or 250 ℃; in the step II), the temperature after cooling is preferably 15-30 ℃, and specifically can be 15 ℃, 20 ℃, 25 ℃ or 30 ℃.

In the preparation step of the magnetic magnesium alloy particles provided by the invention, after the magnesium alloy magnetic material is plated, a magnesium alloy magnetic film layer is formed on the gelatin film layer. The thickness of the magnesium alloy magnetic film layer is preferably 10-1000 nm, and specifically can be 10nm, 20nm, 30nm, 40nm, 50nm, 70nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm or 1000 nm.

In the preparation step of the magnetic magnesium alloy particles provided by the invention, after a magnesium alloy magnetic film layer is formed, a multilayer composite material is obtained, and then the multilayer composite material is heated in water until a gelatin film layer in the material is dissolved. Wherein the heating temperature is preferably 60-75 deg.C, specifically 60 deg.C, 61 deg.C, 62 deg.C, 63 deg.C, 64 deg.C, 65 deg.C, 66 deg.C, 67 deg.C, 68 deg.C, 69 deg.C, 70 deg.C, 71 deg.C, 72 deg.C, 73 deg.C, 74 deg.C or 75 deg.C; the dissolving time is preferably 15-20 min, and specifically can be 15min, 16min, 17min, 18min, 19min or 20 min. In an embodiment provided by the present invention, the heating and dissolving of the multilayer composite material is preferably performed in a water tank, as shown in fig. 2, fig. 2 is a schematic diagram of the operation of heating and dissolving the gelatin film layer provided by the embodiment of the present invention, wherein 1 denotes the water tank, 2 denotes the fixing member, 3 denotes the substrate base plate, 4 denotes the gelatin film layer, and 5 denotes the magnesium alloy magnetic film layer. After the gelatin film layer is dissolved, the magnesium alloy magnetic film layer is separated from the substrate base plate.

In the preparation step of the magnetic magnesium alloy particles provided by the invention, after the magnesium alloy magnetic film layer is obtained by separation, the magnesium alloy magnetic film layer is ground. Wherein the grinding is preferably carried out in a german CMSD2000 type grinder; the shearing rate of the grinding is preferably 8000-10000 rpm, and specifically may be 8000rpm, 8500rpm, 9000rpm, 9500rpm or 10000 rpm; the speed of the grinding rotor is preferably 10-30 m/s, and specifically can be 10m/s, 15m/s, 20m/s, 25m/s or 30 m/s. And after the grinding is finished, obtaining the magnetic magnesium alloy particles.

In the preparation method provided by the invention, after the magnetic magnesium alloy nanoparticles are obtained, the magnetic magnesium alloy nanoparticles, the anti-tumor drug, the polylactic acid and the volatile organic solvent are mixed to obtain a mixed solution. Wherein, the magnetic magnesium alloy nano particles are preferably pretreated before being mixed; the pretreatment comprises the following specific steps: and soaking the magnetic magnesium alloy nanoparticles in a sodium heparin aqueous solution, and taking out and air-drying the magnetic magnesium alloy nanoparticles. In the invention, the concentration of the sodium heparin water solution is preferably 10-30 wt%, and specifically 10 wt%, 15 wt%, 20 wt%, 25 wt% or 30 wt%; the soaking time is preferably 30-60 min, and specifically can be 30min, 35min, 40min, 45min, 50min, 55min or 60 min. In the invention, the magnetic magnesium alloy nanoparticles are pretreated by adopting the heparin sodium aqueous solution, so that the inflammation reaction caused by the degradation process of the magnetic magnesium alloy nanoparticles in vivo can be inhibited to a certain extent.

In the preparation method provided by the invention, the anti-tumor drug includes but is not limited to one or more of Paclitaxel (PTX), Dexamethasone (DXM), saxabemycin, doxorubicin, docetaxel and doxorubicin; the polylactic acid (PLA) is non-toxic and biodegradable, and has good biocompatibility, and the degradation speed of the polylactic acid is related to the molecular weight, so that the degradation speed of the nano robot can be regulated and controlled by selecting the polylactic acid with the proper molecular weight, the release speed of the antitumor drug can be controlled to a certain extent, and the purposes of slow release and long-acting release of the drug can be achieved, wherein the number average molecular weight of the polylactic acid is preferably 5000-50000, and specifically can be 10000, 15000, 20000, 25000, 30000, 35000, 40000, 45000 or 50000; the volatile organic solvent includes, but is not limited to, acetone. In the invention, the mass ratio of the magnetic magnesium alloy nanoparticles to the antitumor drug is preferably 1: (1-3), specifically 1:1, 1:1.5, 1:2, 1:2.5 or 1: 3; the mass ratio of the magnetic magnesium alloy nanoparticles to the polylactic acid is preferably 1: (2-5), specifically 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1: 5; the mass ratio of the magnetic magnesium alloy nanoparticles to the volatile organic solvent is preferably 1: (3-6), specifically 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5 or 1: 6.

In one embodiment of the present invention, the mixed solution is preferably prepared according to the following steps:

i) mixing the antitumor drug and the volatile organic solvent to obtain a liquid medicine;

ii) sequentially adding polylactic acid magnetic magnesium alloy nano particles into the liquid medicine, and mixing to obtain a mixed solution.

In the step of preparing the mixed solution provided in the above embodiment of the present invention, in step i), the mixing is preferably performed under a stirring condition, and the rotation speed of the stirring is preferably 200 to 300r/min, and specifically may be 200r/min, 250r/min, or 300 r/min; the mixing time is preferably 10-15 min, and specifically can be 10min, 11min, 12min, 13min, 14min or 15 min.

In the step of preparing the mixed solution provided by the above embodiment of the present invention, in the step ii), the mixing is preferably performed under stirring and ultrasonic conditions, and the rotation speed of the stirring is preferably 200 to 300r/min, and specifically may be 200r/min, 250r/min or 300 r/min; the mixing time is preferably 30-60 min, and specifically can be 30min, 35min, 40min, 45min, 50min, 55min or 60 min.

In the preparation method provided by the invention, after the mixed solution is obtained, the mixed solution is mixed with water and stirred to volatilize the volatile organic solvent in the mixed system, so as to obtain the suspension. Wherein the mass ratio of the mixed liquid to water is preferably 4: (4-8), specifically 4:4, 4:5, 4:6, 4:7 or 4: 8; the rotation speed of the stirring is preferably 500-2000 r/min, and specifically can be 500r/min, 800r/min, 1000r/min, 1200r/min, 1500r/min, 1700r/min or 2000 r/min; the stirring time is preferably 30-60 min, and specifically can be 30min, 35min, 40min, 45min, 50min, 55min or 60 min.

In the preparation method provided by the invention, the suspension preferably further contains a nonionic surfactant and/or folic acid. Wherein the nonionic surfactant mainly performs a modifying and encapsulating function on the surface of the nano-robot, and includes but is not limited to one or more of TWEEN80 (TWEEN 80), TWEEN 20(TWEEN 20) and poloxamer, preferably TWEEN 80; the folic acid can specifically react with a folic acid receptor on the cell surface to form a compound, has strong binding force and high selectivity on tumors, and can be used as a modified compound of a tumor-targeted drug. In one embodiment provided by the present invention, the non-ionic surfactant and folic acid are preferably added to the suspension in the following manner:

firstly, mixing a nonionic surfactant aqueous solution and a folic acid aqueous solution to obtain a mixture aqueous solution; then, an aqueous solution of the mixture was added dropwise to the suspension.

In the addition manner of the nonionic surfactant and the folic acid provided in the above embodiment of the present invention, the concentration of the nonionic surfactant aqueous solution is preferably 0.5 to 5 wt%, and specifically may be 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%; the concentration of the folic acid aqueous solution is preferably 10 to 50 wt%, and specifically may be 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%; the mass ratio of the nonionic surfactant aqueous solution to the folic acid aqueous solution is preferably (6-8): (4-2), specifically 6:4, 7:3 or 8: 2; the mixing of the nonionic surfactant aqueous solution and the folic acid aqueous solution is preferably carried out under the condition of stirring, the stirring speed is preferably 500-2000 r/min, specifically 500r/min, 1000r/min, 1500r/min or 2000r/min, and the mixing time is preferably 10-30 min, specifically 10min, 15min, 20min, 25min or 30 min.

In the addition manner of the nonionic surfactant and the folic acid provided in the above embodiment of the present invention, the volume ratio of the mixture aqueous solution to the suspension is preferably 3: (5-10), specifically 3:5, 3:5.5, 3:6, 3:6.5, 3:7, 3:7.5, 3:8, 3:8.5, 3:9, 3:9.5 or 3: 10; the dropping speed is preferably 5-20 mL/min, and specifically can be 5mL/min, 10mL/min, 15mL/min or 20 mL/min.

In the preparation method provided by the invention, after the suspension is obtained, the suspension is subjected to centrifugal separation. Wherein the rotating speed of the centrifugal separation is preferably 8000-10000 r/min, and specifically 8000r/min, 8500r/min, 9000r/min, 9500r/min or 10000 r/min; the time of the centrifugal separation is preferably 100-120 min, and specifically can be 100min, 105min, 110min, 115min or 120 min. And after the centrifugal separation is finished, removing the supernatant to obtain the nano robot with the anti-tumor function. In the invention, the nano robot obtained by centrifugal separation is preferably dried, and the drying temperature is preferably 60-100 ℃, and specifically can be 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃; the drying time is preferably 60-90 min, and specifically can be 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min or 100 min.

Firstly, uniformly mixing magnetic magnesium alloy nanoparticles, an anti-tumor drug and polylactic acid in a volatile organic solvent; then mixing the suspension with water and stirring to volatilize the volatile organic solvent to obtain a suspension; finally, insoluble substances in the suspension are separated out in a centrifugal separation mode, and the nano robot with the anti-tumor function is obtained. According to the preparation method provided by the invention, the magnetic magnesium alloy nanoparticles are added into the nano robot, so that on one hand, the nano robot can show good magnetism, and can accurately reach a tumor part under the control of an external magnetic field, and the targeted therapy of the tumor is realized; on the other hand, the magnetic magnesium alloy nanoparticles can be completely degraded, so that the nano robot can show good degradability. Meanwhile, the preparation method provided by the invention can regulate and control the degradation speed of the nano robot by adding the polylactic acid into the nano robot, thereby controlling the drug release speed of the nano robot to a certain extent and achieving the purposes of drug slow release and long-acting release. The nano robot prepared by the method provided by the invention has good size uniformity, magnetism, degradability, anti-tumor function and drug slow-release effect, can efficiently kill tumor cells in a targeted manner, and can be completely degraded or absorbed by a human body after killing the tumor cells without any side effect. The preparation method provided by the invention has stable and controllable production process, is suitable for industrialization, and has wide application prospect in the field of tumor treatment.

The invention also provides the nano robot with the anti-tumor function, which is prepared by adopting the method of the technical scheme. The nano robot provided by the invention has good size uniformity, magnetism, degradability, anti-tumor function and drug slow-release effect, can efficiently kill tumor cells in a targeted manner, can be completely degraded or absorbed by a human body after killing the tumor cells, and has no side effect, so that the nano robot provided by the invention has wide application prospect in the field of tumor treatment.

For the sake of clarity, the following examples are given in detail.

Example 1

1) Preparation of magnetic magnesium alloy nanoparticles

1.1) cleaning: the method comprises the steps of wiping a glass substrate with the size of 300mm multiplied by 400mm multiplied by 0.5mm with alcohol, then putting the glass substrate into an ultrasonic cleaning machine, carrying out ultra-washing with deionized water and alcohol, finally putting the glass substrate into alcohol steam for drying, and when the glass substrate is taken out of the steam, drying the glass substrate quickly because condensed steam is evaporated from the surface. In the present embodiment, the ultrasonic power in each ultrasonic process is 150W.

1.2) spin coating gelatin film layer: placing the glass substrate in a working table of an automatic knife scraping rotary glue spreading machine, automatically positioning, automatically scraping a thin gelatin film layer in a rotary mode through a centrifugal law, controlling the rotary scraping speed to be 1200rpm, the rotary scraping time to be 12 seconds and the uniformity to be within +/-3%, and then placing the glass substrate in a drying box at the temperature of 25 +/-1 ℃ to be dried and formed into a film; the working environment is a dust-free space (hundred grades), the humidity is 50 percent, and the thickness of the gelatin film is controlled to be 15 mu m.

1.2.1) gelatin solution used for spin coating was prepared according to the following steps: swelling gelatin granules in distilled water, heating and stirring to 60 ℃ for dissolution, and adding glycerol to prepare gelatin solution. Wherein the mass ratio of the distilled water to the gelatin granules to the glycerol is 70:20: 10.

The material structure obtained in step 1.2) is shown in a diagram a in fig. 3, fig. 3 is a partial process flow diagram for preparing a magnesium alloy drug-loaded nano robot provided by the embodiment of the invention, in the diagram, 11 represents a substrate, 12 represents a gelatin film layer, 13 represents a gelatin film layer after grid printing, and 14 represents a magnetic film layer.

1.3) grid printing: firstly, conveying a substrate coated with a gelatin film layer in a spin coating mode onto a worktable of a full-automatic flat-bed printing machine through a conveying device, automatically positioning, and then heating the substrate to enable the temperature of the gelatin film to rise to 40 ℃ so as to enable the gelatin film to become soft; then, the nano-scale metal screen printing plate (made of stainless steel and in a round grid shape) is buckled, the printing speed is 6m/min, and the downward pressing gravity is 0.4 kg; immediately after printing, the temperature was reduced to below 20 ℃ and the pattern was set to give the structure shown in b in fig. 3.

1.4) magnesium alloy magnetic film sputtering: plating a magnesium alloy film layer on the gelatin film layer after grid printing by adopting a vacuum magnetron sputtering method to obtain a structure shown as a figure c in figure 3; the sputtering rate is 7nm/s, the coating time is 80s, and the vacuum degree is 5 multiplied by 10^-4Pa, 3000W of power, the substrate temperature at 90 ℃ and the thickness of the film layer at 100 nm.

1.4.1) the magnesium alloy target material used by the vacuum magnetron sputtering comprises the following components: nd 4 wt%, Fe 4 wt%, SiO₂12 wt%, Mn 4 wt%, Zn 15 wt%, and the balance Mg;

1.4.2) preparation of magnesium alloy target: carrying out solid solution treatment on the magnetic magnesium alloy for 7.5 hours at 750 ℃ to obtain a magnetic magnesium alloy melt; and then cooling the magnesium alloy melt to 250 ℃, casting the cooled magnesium alloy melt into a die preheated to 200 ℃, cooling to 25 ℃, and extruding and shaping to obtain the magnesium alloy target (100mm multiplied by 50mm multiplied by 6 mm).

1.5) magnetic thin film separation: horizontally placing the multilayer composite material prepared in the step 4) in a flowing pure water fixing groove, wherein the water temperature is 70 ℃, slowly dissolving the gelatin layer in water, and after the gelatin layer is completely dissolved (about 15-20 min), separating the magnesium alloy magnetic film layer from the substrate base plate to obtain the structure shown in a diagram d in fig. 3.

1.6) grinding and granulating: grinding the magnesium alloy magnetic film layer obtained in the step 1.5) by a Germany CMSD2000 type grinder, wherein the shearing rate is 9000rpm, the rotor speed is 20m/s, and after the grinding is finished, magnetic magnesium alloy nano-particles with the particle diameter of 120nm are obtained.

2) Preparation of nano robot with anti-tumor function

2.1) soaking the magnetic magnesium alloy nano-particles prepared in the step 1) in a sodium heparin aqueous solution (with the concentration of 20 wt%) for 45min, taking out and air-drying.

2.2) dissolving paclitaxel in acetone, stirring for 10-15 min until the paclitaxel is completely dissolved, then sequentially adding polylactic acid (with the number average molecular weight of 20000) and the magnetic magnesium alloy nanoparticles treated in the step 2.1), wherein the mass ratio of the paclitaxel, the acetone, the polylactic acid and the magnetic magnesium alloy nanoparticles is 2:4:3:1, stirring while performing ultrasonic treatment, and stirring at the speed of 200r/min for 45min to obtain a mixed solution.

2.3) slowly adding deionized water into the mixed solution prepared in the step 2.2) under the stirring condition, wherein the mass ratio of the mixed solution to the deionized water is 4:6, and continuously stirring for a certain time to volatilize and remove acetone to obtain colloidal suspension with opalescence. Wherein the stirring speed is 1000r/min, and the stirring time is about 40 min.

2.4) mixing an aqueous solution of TWEEN80 having a concentration of 2 wt% and an aqueous solution of folic acid having a concentration of 30 wt% in a mass ratio of 7:3, and stirring at a stirring speed of 1000r/min for 20min to obtain an aqueous mixture solution.

2.5) slowly dripping the mixture aqueous solution prepared in the step 2.4) into the suspension prepared in the step 2.3), wherein the volume ratio of the mixture aqueous solution to the suspension is 3:7, the dripping speed is 10mL/min, and stirring and mixing for 30min after the dripping is finished.

2.6) placing the mixture prepared in the step 2.5) in a centrifuge tube, 9000r/min and centrifuging for 100 min. And then, removing the supernatant, and putting the centrifugal tube into a vacuum drying oven to constant weight (the drying temperature is 80 ℃, and the drying time is about 70min) to obtain the nano robot with the anti-tumor function.

The prepared nano robot with the anti-tumor function is observed by a transmission electron microscope (JEM-100SX transmission electron microscope, JEOL company, Japan), and the result shows that: the nano robot with the anti-tumor function prepared by the embodiment has the advantages that most of the nano robot with the anti-tumor function presents round and uniform spherical particles, the average particle size is 180nm, and no adhesion exists among the particles.

Example 2

1) Preparation of magnetic magnesium alloy nanoparticles

1.1) cleaning: the method comprises the steps of wiping a glass substrate with the size of 300mm multiplied by 400mm multiplied by 0.5mm with alcohol, then putting the glass substrate into an ultrasonic cleaning machine, carrying out ultra-washing with deionized water and alcohol, finally putting the glass substrate into alcohol steam for drying, and when the glass substrate is taken out of the steam, drying the glass substrate quickly because condensed steam is evaporated from the surface. In the present embodiment, the ultrasonic power in each ultrasonic process is 150W.

1.2) spin coating gelatin film layer: placing the glass substrate in a working table of an automatic knife scraping rotary glue spreading machine, automatically positioning, automatically scraping a thin gelatin film layer in a rotary mode through a centrifugal law, controlling the rotary scraping speed to be 1000rpm, the rotary scraping time to be 10 seconds and the uniformity to be within +/-3%, and then placing the glass substrate in a drying box at the temperature of 25 +/-1 ℃ to be dried and formed into a film; the working environment is a dust-free space (hundred grades), the humidity is 50 percent, and the thickness of the gelatin film is controlled to be 10 mu m.

1.2.1) gelatin solution used for spin coating was prepared according to the following steps: swelling gelatin granules in distilled water, heating and stirring to 60 ℃ for dissolution, and adding glycerol to prepare gelatin solution. Wherein the mass ratio of the distilled water to the gelatin granules to the glycerol is 70:20: 10.

The material structure obtained in step 1.2) is shown in a diagram a in fig. 3, fig. 3 is a partial process flow diagram for preparing a magnesium alloy drug-loaded nano robot provided by the embodiment of the invention, in the diagram, 11 represents a substrate, 12 represents a gelatin film layer, 13 represents a gelatin film layer after grid printing, and 14 represents a magnetic film layer.

1.3) grid printing: firstly, conveying a substrate coated with a gelatin film layer in a spin coating mode onto a worktable of a full-automatic flat-bed printing machine through a conveying device, automatically positioning, and then heating the substrate to enable the temperature of the gelatin film to rise to 40 ℃ so as to enable the gelatin film to become soft; then, the nano-scale metal screen printing plate (made of stainless steel and in a round grid shape) is buckled, the printing speed is 5m/min, and the downward pressing gravity is 0.3 kg; immediately after printing, the temperature was reduced to below 20 ℃ and the pattern was set to give the structure shown in b in fig. 3.

1.4) magnesium alloy magnetic film sputtering: plating a magnesium alloy film layer on the gelatin film layer after grid printing by adopting a vacuum magnetron sputtering method to obtain a structure shown as a figure c in figure 3; the sputtering rate is 5nm/s, the coating time is 80s, and the vacuum degree is 5 multiplied by 10^-4Pa, 3300W of power, substrate temperature at 90 deg.C, and film thickness at 90 nm.

1.4.1) the magnesium alloy target material used by the vacuum magnetron sputtering comprises the following components: nd 4 wt%, Fe 4 wt%, SiO₂12 wt%, Mn 4 wt%, Zn 15 wt%, and the balance Mg;

1.4.2) preparation of magnesium alloy target: carrying out solid solution treatment on the magnetic magnesium alloy for 7.5 hours at 750 ℃ to obtain a magnetic magnesium alloy melt; and then cooling the magnesium alloy melt to 250 ℃, casting the cooled magnesium alloy melt into a die preheated to 200 ℃, cooling to 25 ℃, and extruding and shaping to obtain the magnesium alloy target (100mm multiplied by 50mm multiplied by 6 mm).

1.5) magnetic thin film separation: horizontally placing the multilayer composite material prepared in the step 4) in a flowing pure water fixing groove, wherein the water temperature is 70 ℃, slowly dissolving the gelatin layer in water, and after the gelatin layer is completely dissolved (about 15-20 min), separating the magnesium alloy magnetic film layer from the substrate base plate to obtain the structure shown in a diagram d in fig. 3.

1.6) grinding and granulating: grinding the magnesium alloy magnetic film layer obtained in the step 1.5) by a Germany CMSD2000 type grinder, wherein the shearing rate is 9000rpm, the rotor speed is 20m/s, and after the grinding is finished, magnetic magnesium alloy nano-particles with the particle diameter of 90nm are obtained.

2) Preparation of nano robot with anti-tumor function

2.1) soaking the magnetic magnesium alloy nano-particles prepared in the step 1) in a sodium heparin aqueous solution (with the concentration of 20 wt%) for 40min, taking out and air-drying.

2.2) dissolving paclitaxel in acetone, stirring for 10-15 min until the paclitaxel is completely dissolved, then sequentially adding polylactic acid (with the number average molecular weight of 20000) and the magnetic magnesium alloy nanoparticles treated in the step 2.1), wherein the mass ratio of the paclitaxel, the acetone, the polylactic acid and the magnetic magnesium alloy nanoparticles is 2:4:3:1, stirring while performing ultrasonic treatment, and stirring at the speed of 200r/min for 45min to obtain a mixed solution.

2.3) slowly adding deionized water into the mixed solution prepared in the step 2.2) under the stirring condition, wherein the mass ratio of the mixed solution to the deionized water is 4:6, and continuously stirring for a certain time to volatilize and remove acetone to obtain colloidal suspension with opalescence. Wherein the stirring speed is 1000r/min, and the stirring time is about 40 min.

2.4) mixing an aqueous solution of TWEEN80 having a concentration of 2 wt% and an aqueous solution of folic acid having a concentration of 30 wt% in a mass ratio of 8:2, and stirring at a stirring speed of 1000r/min for 20min to obtain an aqueous mixture solution.

2.5) slowly dripping the mixture aqueous solution prepared in the step 2.4) into the suspension prepared in the step 2.3), wherein the volume ratio of the mixture aqueous solution to the suspension is 3:7, the dripping speed is 8mL/min, and stirring and mixing for 30min after the dripping is finished.

2.6) placing the mixture prepared in the step 2.5) in a centrifuge tube, 9000r/min and centrifuging for 100 min. And then, removing the supernatant, and putting the centrifugal tube into a vacuum drying oven to constant weight (the drying temperature is 80 ℃, and the drying time is about 70min) to obtain the nano robot with the anti-tumor function.

The prepared nano robot with the anti-tumor function is observed by a transmission electron microscope (JEM-100SX transmission electron microscope, JEOL company, Japan), and the result shows that: the nano robot with the anti-tumor function prepared by the embodiment has the advantages that most of the nano robot with the anti-tumor function presents round and uniform spherical particles, the average particle size is 150nm, and no adhesion exists among the particles.

Example 3

1) Preparation of magnetic magnesium alloy nanoparticles

1.1) cleaning: the method comprises the steps of wiping a glass substrate with the size of 300mm multiplied by 400mm multiplied by 0.5mm with alcohol, then putting the glass substrate into an ultrasonic cleaning machine, carrying out ultra-washing with deionized water and alcohol, finally putting the glass substrate into alcohol steam for drying, and when the glass substrate is taken out of the steam, drying the glass substrate quickly because condensed steam is evaporated from the surface. In the present embodiment, the ultrasonic power in each ultrasonic process is 200W.

1.2) spin coating gelatin film layer: placing the glass substrate in a working table of an automatic knife scraping rotary glue spreading machine, automatically positioning, automatically scraping a thin gelatin film layer in a rotary mode through a centrifugal law, controlling the rotary scraping speed to be 1500rpm, the rotary scraping time to be 15 seconds and the uniformity to be within +/-3%, and then placing the glass substrate in a drying box at the temperature of 25 +/-1 ℃ to be dried and formed into a film; the working environment is a dust-free space (hundred grades), the humidity is 50 percent, and the thickness of the gelatin film is controlled to be 20 mu m.

1.2.1) gelatin solution used for spin coating was prepared according to the following steps: swelling gelatin granules in distilled water, heating and stirring to 60 ℃ for dissolution, and adding glycerol to prepare gelatin solution. Wherein the mass ratio of the distilled water to the gelatin granules to the glycerol is 70:20: 10.

The material structure obtained in step 1.2) is shown in a diagram a in fig. 3, fig. 3 is a partial process flow diagram for preparing a magnesium alloy drug-loaded nano robot provided by the embodiment of the invention, in the diagram, 11 represents a substrate, 12 represents a gelatin film layer, 13 represents a gelatin film layer after grid printing, and 14 represents a magnetic film layer.

1.3) grid printing: firstly, conveying a substrate coated with a gelatin film layer in a spin coating mode onto a worktable of a full-automatic flat-bed printing machine through a conveying device, automatically positioning, and then heating the substrate to enable the temperature of the gelatin film to rise to 40 ℃ so as to enable the gelatin film to become soft; then, the nano-scale metal screen printing plate (made of stainless steel and in a round grid shape) is buckled, the printing speed is 8m/min, and the downward pressing gravity is 0.5 kg; immediately after printing, the temperature was reduced to below 20 ℃ and the pattern was set to give the structure shown in b in fig. 3.

1.4) magnesium alloy magnetic film sputtering: plating a magnesium alloy film layer on the gelatin film layer after grid printing by adopting a vacuum magnetron sputtering method to obtain a structure shown as a figure c in figure 3; the sputtering rate is 10nm/s, the coating time is 80s, and the vacuum degree is 5 multiplied by 10^-4Pa, 3000W of power, the substrate temperature at 90 ℃ and the thickness of the film layer at 150 nm.

1.4.1) the magnesium alloy target material used by the vacuum magnetron sputtering comprises the following components: nd 5 wt%, Fe 5 wt%, SiO₂15 wt%, Mn 4 wt%, Zn 20 wt%, and the balance Mg;

1.4.2) preparation of magnesium alloy target: carrying out solid solution treatment on the magnetic magnesium alloy for 7.5 hours at 750 ℃ to obtain a magnetic magnesium alloy melt; and then cooling the magnesium alloy melt to 250 ℃, casting the cooled magnesium alloy melt into a die preheated to 200 ℃, cooling to 25 ℃, and extruding and shaping to obtain the magnesium alloy target (100mm multiplied by 50mm multiplied by 6 mm).

1.5) magnetic thin film separation: horizontally placing the multilayer composite material prepared in the step 4) in a flowing pure water fixing groove, wherein the water temperature is 70 ℃, slowly dissolving the gelatin layer in water, and after the gelatin layer is completely dissolved (about 15-20 min), separating the magnesium alloy magnetic film layer from the substrate base plate to obtain the structure shown in a diagram d in fig. 3.

1.6) grinding and granulating: grinding the magnesium alloy magnetic film layer obtained in the step 1.5) by a Germany CMSD2000 type grinder, wherein the shearing rate is 9000rpm, the rotor speed is 20m/s, and after the grinding is finished, magnetic magnesium alloy nano-particles with the particle diameter of 150nm are obtained.

2) Preparation of nano robot with anti-tumor function

2.1) soaking the magnetic magnesium alloy nano-particles prepared in the step 1) in a sodium heparin aqueous solution (with the concentration of 20 wt%) for 50min, taking out and air-drying.

2.2) dissolving paclitaxel in acetone, stirring for 10-15 min until the paclitaxel is completely dissolved, then sequentially adding polylactic acid (with the number average molecular weight of 20000) and the magnetic magnesium alloy nanoparticles treated in the step 2.1), wherein the mass ratio of the paclitaxel, the acetone, the polylactic acid and the magnetic magnesium alloy nanoparticles is 2:4:3:1, stirring while performing ultrasonic treatment, and stirring at the speed of 200r/min for 50min to obtain a mixed solution.

2.3) slowly adding deionized water into the mixed solution prepared in the step 2.2) under the stirring condition, wherein the mass ratio of the mixed solution to the deionized water is 4:6, and continuously stirring for a certain time to volatilize and remove acetone to obtain colloidal suspension with opalescence. Wherein the stirring speed is 1000r/min, and the stirring time is about 40 min.

2.4) mixing an aqueous solution of TWEEN80 with a concentration of 2 wt% and an aqueous solution of folic acid with a concentration of 30 wt% in a mass ratio of 6:4, and stirring at a stirring speed of 1000r/min for 20min to obtain an aqueous mixture solution.

2.5) slowly dripping the mixture aqueous solution prepared in the step 2.4) into the suspension prepared in the step 2.3), wherein the volume ratio of the mixture aqueous solution to the suspension is 3:7, the dripping speed is 10mL/min, and stirring and mixing for 30min after the dripping is finished.

2.6) placing the mixture prepared in the step 2.5) in a centrifuge tube, 9000r/min and centrifuging for 100 min. And then, removing the supernatant, and putting the centrifugal tube into a vacuum drying oven to constant weight (the drying temperature is 80 ℃, and the drying time is about 70min) to obtain the nano robot with the anti-tumor function.

The prepared nano robot with the anti-tumor function is observed by a transmission electron microscope (JEM-100SX transmission electron microscope, JEOL company, Japan), and the result shows that: the nano robot with the anti-tumor function prepared by the embodiment has the advantages that most of the nano robot with the anti-tumor function presents round and uniform spherical particles, the average particle size is 200nm, and no adhesion exists among the particles.

Evaluation of Effect

Diluting 1mg of the nano-robot with the anti-tumor function prepared in the above embodiment into saline, injecting the saline into a tumor region of a patient, completely covering the tumor region (the nano-robot is defined as completely covering the tumor region by the high selectivity of folic acid on the tumor or an external magnetic control system, the nano-robot is over 5mm beyond the tumor region), and finally identifying the biocompatibility and degradation condition of the nano-robot in vivo by images such as CT and the like, wherein the results are shown in table 1:

TABLE 1 biocompatibility and degradation of different test samples

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.