One-step preparation of biocompatible surface-modified tunable amphiphilic Janus nanoparticles and their applications

Abstract

The invention discloses a one-step method for preparing biocompatible surface-modified adjustable amphiphilic Janus nanoparticles and applications thereof, and belongs to the field of particle materials. The method prepares amphiphilic Janus nanoparticles by coprecipitation and phase separation, and the preparation method is simple and easy. The size, composition and morphology of the prepared amphiphilic Janus particles can be precisely regulated. Based on the amphiphilic structure, the prepared amphiphilic Janus particles can be used as surfactants to well stabilize the emulsion formed by oil and water. At the same time, hydrophobic drugs, functional nanomaterials and / or functional polymers can be encapsulated to achieve application in the field of drug delivery. In addition, the prepared amphiphilic Janus nanoparticles have good biocompatibility and also have broad application prospects in the fields of biomedicine, food, cosmetics, etc.

Description

Technical Field

[0001] The present invention relates to the field of particulate materials, and particularly to a one-step method for preparing biocompatible amphiphilic Janus nanoparticles with adjustable surface modification and its applications. Background Art

[0002] Janus was originally the name of the two-faced god in ancient Roman mythology. The concept of Janus particles was first proposed by Professor DeGennes, a French scientist, in his Nobel Prize speech in 1991. He cleverly borrowed the term Janus to describe particles with dual properties, that is, a structure in which the two hemispheres of a particle have different characteristics. Due to their unique properties, Janus particles can adapt to complex multiphase usage environments. In the industrial field, Janus particles can be used for interface modification to improve the surface activity and stability of materials, thereby improving the quality and performance of products; in the agricultural field, Janus particles can be used to control the release rate of fertilizers to increase crop yield and quality; in the chemical industry, Janus particles can be used for catalytic reactions and separation and purification to improve the efficiency of chemical reactions and the purity of products; in the biological field, Janus particles can be used for molecular probes and targeted drug delivery to help doctors diagnose and treat diseases more accurately.

[0003] Janus particles are classified into amphiphilic, thermosensitive, magnetic-responsive, pH-responsive, etc. from the perspective of performance. Among them, amphiphilic Janus nanoparticles have great advantages in stabilizing Pickering emulsions due to their simultaneous surfactant properties and solid particle effects.

[0004] Currently, amphiphilic Janus nanoparticles are mainly synthesized by surface modification methods, that is, first synthesizing Janus nanoparticles and then modifying their surfaces with hydrophilic materials to achieve amphiphilicity of the two hemispheres. However, this method has cumbersome steps and takes a long time; while the one-step method for directly constructing amphiphilic Janus nanoparticles is simpler but relatively difficult to achieve. Therefore, it is of crucial significance to propose a simple and efficient one-step method for preparing amphiphilic Janus nanoparticles. This new method aims to simplify the preparation process, improve the preparation efficiency, and at the same time maintain the performance and quality of Janus particles. This new method is expected to bring more extensive applications of Janus nanoparticles in various application fields and promote the development and innovation of related industries. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the present invention provides a one-step method for preparing biocompatible surface-modifiable amphiphilic Janus nanoparticles and their applications. The amphiphilic Janus nanoparticles are prepared by coprecipitation and phase separation. The preparation method is simple and easy to implement. The size, composition, and morphology of the prepared amphiphilic Janus particles can be precisely controlled. Based on their amphiphilic structure, they can be used as surfactants to well stabilize emulsions formed by water and oil phases. At the same time, they can encapsulate hydrophobic drugs, functional nanomaterials, and / or functional polymers, thereby realizing applications in the field of drug delivery. In addition, the amphiphilic Janus nanoparticles prepared by the present invention have good biocompatibility and also have broad application prospects in the fields of biomedicine, food, cosmetics, etc.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One-step method for preparing biocompatible surface-modifiable amphiphilic Janus nanoparticles, comprising the following steps:

[0008] (1) Dissolve shellac in tetrahydrofuran, heat and stir until the shellac is completely dissolved, then add polylactic acid and hydrophilically modified polylactic acid to obtain an organic phase solution; dissolve the surfactant in deionized water and obtain an aqueous phase solution after ultrasonic dispersion;

[0009] (2) Heat the aqueous phase solution prepared in step (1), quickly inject the organic phase solution prepared in step (1) into the aqueous phase solution, shake and mix evenly to obtain a dispersion of amphiphilic shellac-polylactic acid Janus nanoparticles in the aqueous phase solution;

[0010] (3) Place the dispersion of amphiphilic shellac-polylactic acid Janus nanoparticles in the aqueous phase solution prepared in step (2) in a fume hood, let it stand, centrifuge, remove the supernatant, and wash with deionized water to obtain a dispersion of amphiphilic Janus nanoparticles in deionized water.

[0011] As a preference of the present invention, in step (1), the mass range of the shellac added in 1 mL of tetrahydrofuran is 1-100 mg; further preferably, the mass range of the shellac added in 1 mL of tetrahydrofuran is 1-50 mg. The shellac is a natural encapsulating material, which is easily soluble in organic solvents such as ethanol and alkaline solutions, but hardly soluble in neutral or acidic solutions.

[0012] The mass range of the polylactic acid added in 1 mL of tetrahydrofuran is 1-100 mg; further preferably, the mass range of the polylactic acid added in 1 mL of tetrahydrofuran is 1-50 mg. The polylactic acid is a synthetic polymer material, which is easily soluble in tetrahydrofuran but hardly soluble in ethanol.

[0013] The molecular weight range of the polylactic acid is 1,000 - 5,000; further preferably, the molecular weight of the polylactic acid is 3,000.

[0014] The hydrophilic modified polylactic acid includes polyethylene glycol - polylactic acid, folic acid - polyethylene glycol - polylactic acid, biotin - polyethylene glycol - polylactic acid or streptavidin - polyethylene glycol - polylactic acid, and the molecular weight of the polyethylene glycol is 1,000 - 14,000.

[0015] The mass fraction of the hydrophilic modified polylactic acid in the total polylactic acid is 0.5 - 10%.

[0016] The surfactant is sodium dodecyl sulfate or Tween 80.

[0017] The mass fraction range of the surfactant added in 1 mL of deionized water is 0.1 - 5%; further preferably, the mass fraction range of the surfactant added in 1 mL of deionized water is 0.8 - 2%.

[0018] As a preference of the present invention, in step (2), the preparation process needs to be carried out in a water bath at 65°C - 90°C, and the generated particles can be stable for a long time at room temperature; further preferably, the water bath temperature is 70°C.

[0019] The injection speed when the organic phase solution is injected into the aqueous phase solution is 5 ml / h - 30 ml / h; further preferably, the injection speed is 15 ml / h - 20 ml / h.

[0020] The volume percentage range of the organic phase solution and the surfactant aqueous solution is 1.67% - 6.67%; further preferably, the volume fraction range of the organic phase solution and the surfactant aqueous solution is 1.67% - 3.33%.

[0021] As a preference of the present invention, in step (3), the standing time in the fume hood ranges from 4 h to 12 h; further preferably, the standing time in the fume hood ranges from 6 h to 12 h.

[0022] The specific conditions for centrifugation are: centrifuging at 8,000 - 15,000 rpm for 5 - 15 min; further preferably, the specific conditions for centrifugation are: centrifuging at 10,000 - 13,000 rpm for 5 - 10 min.

[0023] The range of the number of centrifugal washing times is 3 - 10 times; further preferably, the number of centrifugal washing times is 3 - 5 times.

[0024] The size, composition and morphology of the amphiphilic Janus nanoparticles can be precisely regulated by adjusting the contents of shellac and polylactic acid and the mass fraction of the hydrophilic modified polylactic acid in the total polylactic acid.

[0025] A preparation method of an amphiphilic Janus nanoparticle-stabilized oil-in-water / water-in-oil emulsion. Add the dispersion of the prepared amphiphilic Janus nanoparticles in deionized water to the oil phase, such that the volume ratio of the oil phase to the dispersion is 1:1, and vortex mix for 0.5 - 5 min to obtain an amphiphilic Janus nanoparticle-stabilized oil-in-water emulsion or water-in-oil emulsion.

[0026] As a preference of the present invention, when the diameter of the shellac hemisphere / the diameter of the polylactic acid hemisphere is greater than 1, an amphiphilic Janus nanoparticle-stabilized oil-in-water emulsion is obtained; when the diameter of the shellac hemisphere / the diameter of the polylactic acid hemisphere is less than 1, an amphiphilic Janus nanoparticle-stabilized water-in-oil emulsion is obtained.

[0027] As a preference of the present invention, the oil phase is silk oil, silicone oil, n-hexadecane or perfluorohexane.

[0028] By adding a hydrophobic drug, a functional nanomaterial and / or a functional polymer to the organic phase solution, the prepared Janus nanoparticles can be applied in the field of drug loading.

[0029] The beneficial effects of the present invention are as follows:

[0030] (1) The present invention proposes a biocompatible surface-modifiable amphiphilic Janus nanoparticle and a one-step preparation method thereof, which are characterized by being convenient, efficient and green. The materials and solvents used are non-toxic and harmless. This method solves the problems such as the cumbersome preparation steps of traditional amphiphilic Janus nanoparticles, and is expected to be directly applied to industries such as food, cosmetics and pharmaceuticals, with the prospect of large-scale production.

[0031] (2) In the method used in the present invention, no harmful substances are generated during the experimental process. The prepared amphiphilic Janus nanoparticles have good biocompatibility, are non-toxic and non-irritating to the human body, and can be applied to the biomedical field.

[0032] (3) The surface modification of the prepared amphiphilic Janus nanoparticles of the present invention is adjustable and can be used for the rapid preparation of stable oil-in-water / water-in-oil emulsions.

[0033] (4) The biocompatible surface-modifiable amphiphilic Janus nanoparticles prepared by the present invention can be used in the field of drug loading. Description of the Drawings

[0034] The present invention will be further described below in conjunction with the drawings and embodiments.

[0035] Figure 1 It is a schematic diagram for the one-step preparation of biocompatible surface-modifiable amphiphilic Janus nanoparticles;

[0036] Figure 2 Proof diagram of amphiphilicity of biocompatible surface-modifiable amphiphilic Janus nanoparticles prepared in Example 4;

[0037] Figure 3 Scanning electron micrograph of amphiphilic Janus nanoparticles prepared by regulating the size of amphiphilic Janus nanoparticles in Example 5.

[0038] Figure 4 Scanning electron micrograph of amphiphilic Janus nanoparticles prepared by regulating the shape of amphiphilic Janus nanoparticles in Example 6.

[0039] Figure 5 Schematic diagram of oil-in-water / water-in-oil emulsion stabilized by amphiphilic Janus nanoparticles prepared in Example 8. Detailed implementation manners

[0040] The present invention will be further described and explained below in conjunction with the detailed implementation manners. The described embodiments are only demonstrations of the disclosed content and do not delimit the scope of limitation. Without conflict, the technical features of each embodiment in the present invention can be combined accordingly.

[0041] Example 1: Preparation of amphiphilic shellac-polylactic acid Janus nanoparticles

[0042] Refer to the appendix Figure 1 , and prepare amphiphilic Janus nanoparticles by the method of the present invention. The specific steps are as follows:

[0043] (1) Prepare the organic phase solution: Dissolve 10 mg of shellac in 1 mL of tetrahydrofuran organic solvent to obtain a 10 mg / mL shellac / tetrahydrofuran solution, and then add polylactic acid and hydrophilic modified polylactic acid. The total concentration of polylactic acid is 10 mg / mL, and the mass fraction of hydrophilic modified polylactic acid in the total polylactic acid is 2.5%; Prepare the aqueous phase solution: Dissolve TW80 in deionized water, and the mass fraction of TW80 in deionized water is 1%. After ultrasonic dispersion, an aqueous phase solution is obtained.

[0044] (2) Heat the aqueous phase solution prepared in step (1) to 70 °C. At this temperature, use a pipette and a 1-200 μL gel spotting pipette tip (inner diameter 300 μm) to aspirate 100 μL of the organic phase solution obtained in step (1), and then inject it into a glass bottle containing 3 mL of the aqueous phase solution at a speed of 10 mL / min to form amphiphilic Janus nanoparticles (as shown in the appendix Figure 1 ).

[0045] (3) Place the amphiphilic shellac - polylactic acid Janus nanoparticle dispersion prepared in step (2) in a fume hood for 6 h to volatilize the tetrahydrofuran organic solvent in the solution. Then, take the above - mentioned solution, centrifuge it at 12,000 rpm for 10 min, remove the supernatant, and wash it 3 times with deionized water to obtain a dispersion of amphiphilic Janus nanoparticles in deionized water.

[0046] Example 2: Preparation of amphiphilic shellac - polylactic acid Janus nanoparticles

[0047] Refer to the appendix Figure 1 , and use the method of the present invention to prepare amphiphilic Janus nanoparticles. The specific steps are as follows:

[0048] (1) Prepare the organic - phase solution: Dissolve 20 mg of shellac in 1 mL of tetrahydrofuran organic solvent to obtain a 20 mg / mL shellac / tetrahydrofuran solution; then add polylactic acid and hydrophilically modified polylactic acid. The total concentration of polylactic acid is 20 mg / mL, and the mass fraction of hydrophilically modified polylactic acid in the total polylactic acid is 2.5%; Prepare the aqueous - phase solution: Dissolve TW80 in deionized water, and the mass fraction of TW80 in deionized water is 1%. After ultrasonic dispersion, an aqueous - phase solution is obtained.

[0049] (2) Heat the aqueous - phase solution prepared in step (1) to 70 °C. At this temperature, use a pipette and a 1 - 200 μL gel - loading tip (inner diameter 300 μm) to aspirate 100 μL of the organic - phase solution obtained in step (1), and then inject it into a glass bottle containing 3 mL of the aqueous - phase solution at a speed of 10 mL / min to form amphiphilic Janus nanoparticles.

[0050] (3) Place the amphiphilic shellac - polylactic acid Janus nanoparticle dispersion prepared in step (2) in a fume hood for 6 h to volatilize the tetrahydrofuran organic solvent in the solution. Then, take the above - mentioned solution, centrifuge it at 12,000 rpm for 10 min, remove the supernatant, and wash it 3 times with deionized water to obtain a dispersion of amphiphilic Janus nanoparticles in deionized water.

[0051] Example 3: Preparation of amphiphilic shellac - polylactic acid Janus nanoparticles

[0052] Refer to the appendix Figure 1 , and use the method of the present invention to prepare amphiphilic Janus nanoparticles. The specific steps are as follows:

[0053] (1) Prepare the organic phase solution: Dissolve 20 mg of shellac in 1 mL of tetrahydrofuran organic solvent to obtain a 20 mg / mL shellac / tetrahydrofuran solution; then add polylactic acid and hydrophilically modified polylactic acid, with the total concentration of polylactic acid being 20 mg / mL and the mass fraction of hydrophilically modified polylactic acid in the total polylactic acid being 5%; Prepare the aqueous phase solution: Dissolve TW80 in deionized water, with the mass fraction of TW80 in deionized water being 1%, and obtain the aqueous phase solution after ultrasonic dispersion.

[0054] (2) Heat the aqueous phase solution prepared in step (1) to 70 °C. At this temperature, use a pipette and a 1 - 200 μL gel spotting tip (inner diameter 300 μm) to aspirate 100 μL of the organic phase solution obtained in step (1), and then inject it into a glass bottle containing 3 mL of the aqueous phase solution at a rate of 10 mL / min to form amphiphilic Janus nanoparticles (as shown in the attachment Figure 1 ).

[0055] (3) Place the amphiphilic shellac - polylactic acid Janus nanoparticle dispersion prepared in step (2) in a fume hood for 6 h to volatilize the tetrahydrofuran organic solvent in the solution. Subsequently, take the above solution, centrifuge it at 12000 rpm for 10 min, remove the supernatant, and wash it 3 times with deionized water to obtain a dispersion of amphiphilic Janus nanoparticles in deionized water.

[0056] Example 4: Proof of the amphiphilicity of shellac - polylactic acid Janus nanoparticles

[0057] According to the steps of Example 1, on the premise that other conditions are the same, keep the shellac concentration and the polylactic acid concentration the same, and respectively prepare shellac - polylactic acid Janus nanoparticles without adding hydrophilically modified polylactic acid and shellac - polylactic acid Janus nanoparticles with added hydrophilically modified polylactic acid, where the mass fraction of hydrophilically modified polylactic acid in the total polylactic acid is 2.5%. As Figure 2 shown, by using EDS energy spectrum analysis to analyze the change of element content before and after modification, it is found that the oxygen content in the polylactic acid hemisphere increases, proving that the hydrophilically modified polylactic acid is modified, making the shellac - polylactic acid Janus nanoparticles amphiphilic.

[0058] Example 5: Controlling the size of amphiphilic shellac - polylactic acid Janus nanoparticles

[0059] According to the steps of Example 1, change the concentrations of shellac and polylactic acid in tetrahydrofuran, but keep the shellac concentration and the polylactic acid concentration the same and the mass fraction of hydrophilically modified polylactic acid in the total polylactic acid unchanged at 2.5%, and set the following groups of concentrations: 1 mg / mL, 2 mg / mL, 3 mg / mL, 5 mg / mL, 10 mg / mL, 15 mg / mL, as Figure 3As shown, shellac hemispheres and polylactic acid hemispheres with the same size were respectively prepared, but the overall size of the amphiphilic shellac-polylactic acid Janus nanoparticles varied within the range of several hundred nanometers.

[0060] Example 6: Controlling the shape of amphiphilic shellac-polylactic acid Janus nanoparticles

[0061] According to the steps of Example 1, while keeping the total concentration of shellac and polylactic acid in tetrahydrofuran at 10 mg / mL and the mass fraction of hydrophilically modified polylactic acid in the total polylactic acid at 2.5% unchanged, the ratios of shellac and polylactic acid in it were changed, and the following several sets of ratio relationships were set: 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1. As Figure 4 shown, amphiphilic shellac-polylactic acid Janus nanoparticles with generally the same overall size but gradually changing ratios of the sizes of the two hemispheres were respectively prepared.

[0062] Example 7: Preparing drug-loaded amphiphilic shellac-polylactic acid Janus nanoparticles

[0063] The drug-loaded amphiphilic shellac-polylactic acid Janus nanoparticles were prepared by the method of the present invention, and the specific steps are as follows:

[0064] (1) Prepare the organic phase solution: Dissolve 5 mg of shellac in 1 mL of tetrahydrofuran organic solvent to obtain a 5 mg / mL shellac / tetrahydrofuran solution; then add polylactic acid and hydrophilically modified polylactic acid, with the total concentration of polylactic acid being 5 mg / mL and the mass fraction of hydrophilically modified polylactic acid in the total polylactic acid being 2.5%, and then add 1 mg of the hydrophobic drug paclitaxel; Prepare the aqueous phase solution: Dissolve TW80 in deionized water, with the mass fraction of TW80 in deionized water being 1%, and obtain the aqueous phase solution after ultrasonic dispersion.

[0065] (2) Heat the aqueous phase solution prepared in step (1) to 70 °C. At this temperature, use a pipette and a 1 - 200 μL gel spotting pipette tip (inner diameter 300 μm) to aspirate 100 μL of the organic phase solution obtained in step (1), and then inject it into a glass bottle containing 3 mL of the aqueous phase solution at a speed of 10 mL / min to form amphiphilic Janus nanoparticles.

[0066] (3) Place the dispersion of the amphiphilic shellac-polylactic acid Janus nanoparticles prepared in step (2) in a fume hood for 6 h to volatilize the tetrahydrofuran organic solvent in the solution. Subsequently, take the above solution, centrifuge it at 12,000 rpm for 10 min, remove the supernatant, and wash it 3 times with deionized water to obtain a dispersion of the drug-loaded amphiphilic Janus nanoparticles in deionized water.

[0067] Example 8: Preparation of amphiphilic shellac-polylactic acid Janus nanoparticle water-in-oil / oil-in-water emulsion

[0068] The amphiphilic shellac-polylactic acid Janus nanoparticle water-in-oil / oil-in-water emulsion was prepared by the method of the present invention, and the specific steps are as follows:

[0069] The dispersion of the amphiphilic shellac-polylactic acid Janus nanoparticles prepared according to the examples in deionized water was added to silk oil, and the volume ratio of the oil phase to the dispersion was 1:1. The oil and water phases were vortex-mixed for 1 min to obtain an amphiphilic shellac-polylactic acid Janus nanoparticle-stabilized water-in-oil / oil-in-water emulsion; as Figure 5 shown, when the shellac hemisphere diameter / polylactic acid hemisphere diameter is greater than 1, an oil-in-water emulsion is formed; when the shellac hemisphere diameter / polylactic acid hemisphere diameter is less than 1, a water-in-oil emulsion is formed.

Claims

1. A one-step method for preparing biocompatible surface-modified tunable amphiphilic Janus nanoparticles, characterized in that: The following steps are involved: (1) Preparation of organic and aqueous phase solutions The shellac is dissolved in tetrahydrofuran organic solvent, the concentration of the shellac is 1-100 mg / mL, and after heating and stirring until the shellac is completely dissolved, polylactic acid and hydrophilically modified polylactic acid are added to obtain an organic phase solution; the total concentration of the polylactic acid is 1-100 mg / mL, and the mass fraction of the hydrophilically modified polylactic acid in the total polylactic acid is 0.5-10%; the hydrophilically modified polylactic acid includes polyethylene glycol-polylactic acid, folic acid-polyethylene glycol-polylactic acid, biotin-polyethylene glycol-polylactic acid, and streptavidin-polyethylene glycol-polylactic acid; Dissolving a surfactant in deionized water, wherein the mass fraction of the surfactant in the deionized water is 0.1-5%, and obtaining an aqueous phase solution after ultrasonic dispersion; (2) Preparation of dispersion of amphiphilic Janus nanoparticles in aqueous solution Heat the aqueous solution prepared in step (1) to 65-90 o C, rapidly injecting the organic phase solution prepared in step (1) into the aqueous phase solution at a rate of 5 mL / h-30 mL / h, wherein the volume fraction of the organic phase solution to the aqueous phase solution is 1.67%-6.67%; shaking and mixing to obtain a dispersion of amphiphilic shellac-polylactic acid Janus nanoparticles in the aqueous phase solution; (3) Washing The dispersion of the amphiphilic shellac-polylactic acid Janus nanoparticles in the aqueous solution prepared in step (2) is placed in a fume hood for 6-12 hours, centrifuged, the supernatant is removed, and washed with deionized water for 3-5 times to obtain a dispersion of the amphiphilic Janus nanoparticles in deionized water.

2. The one-step method for preparing biocompatible surface-modified tunable amphiphilic Janus nanoparticles according to claim 1, characterized in that: In step (1), the molecular weight of the polyethylene glycol in the hydrophilically modified polylactic acid is 1000-14000.

3. The one-step method for preparing biocompatible surface-modified tunable amphiphilic Janus nanoparticles according to claim 1, characterized in that: The molecular weight of the polylactic acid is 1000-5000.

4. The one-step method for preparing biocompatible surface-modified tunable amphiphilic Janus nanoparticles according to claim 1, characterized in that: The surfactant is sodium dodecyl sulfate or Tween 80.

5. The one-step method for preparing biocompatible surface-modified tunable amphiphilic Janus nanoparticles according to claim 1, characterized in that: The organic phase solution may also include hydrophobic drugs, functional nanomaterials and / or functional polymers.

6. The one-step method for preparing biocompatible surface-modified and tunable amphiphilic Janus nanoparticles according to claim 5, characterized in that: The hydrophobic drugs include curcumin, paclitaxel, cisplatin or camptothecin; the functional nanomaterials include magnetic nanoparticles and catalytic nanoparticles; the functional polymers include temperature-responsive polymers, pH-responsive polymers, enzyme-responsive polymers or light-responsive polymers.

7. A method for preparing an oil-in-water / water-in-oil emulsion stabilized by amphiphilic Janus nanoparticles, characterized in that: The dispersion of the amphiphilic Janus nanoparticles prepared in claim 1 in deionized water is added to the oil phase so that the volume ratio of the oil phase to the dispersion is 1:1, and vortex mixed for 0.5-5 min to obtain a stable oil-in-water emulsion or oil-in-water emulsion of the amphiphilic Janus nanoparticles.

8. The method for preparing an amphiphilic Janus nanoparticle-stabilized oil-in-water / water-in-oil emulsion according to claim 7, characterized in that: The morphology of the amphiphilic Janus nanoparticles is regulated and controlled. When the diameter of the shellac hemisphere / the diameter of the polylactic acid hemisphere is greater than 1, an oil-in-water emulsion stabilized by the amphiphilic Janus nanoparticles is obtained; when the diameter of the shellac hemisphere / the diameter of the polylactic acid hemisphere is less than 1, an oil-in-water emulsion stabilized by the amphiphilic Janus nanoparticles is obtained.

9. The method for preparing the oil-in-water / water-in-oil emulsion stabilized by amphiphilic Janus nanoparticles according to claim 7, characterized in that: The oil phase is silk oil, silicone oil, n-hexadecane or tetradecafluorohexane.

10. Use of the Janus nanoparticles prepared according to claim 1 in drug loading.

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