A magnetic ionic liquid-modified nanoparticle, a preparation method thereof, and an application thereof

Abstract

The present invention provides a magnetic ionic liquid-modified nanoparticle, a preparation method thereof, and an application. The magnetic ionic liquid-modified nanoparticle has a magnetic core-shell structure, and the modification material on the shell surface is a magnetic ionic liquid. By introducing a magnetic ionic liquid as a ligand, the present invention enhances the magnetic response performance of the magnetic nanoparticle, makes the final product exhibit a fluid state similar to that of the magnetic ionic liquid, and increases its application potential in other fluid fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to a magnetic ionic liquid-modified nanoparticle, a preparation method thereof, and an application thereof. Background Art

[0002] Magnetic nanoparticles have received extensive attention due to their unique structures, excellent magnetic properties, high specific surface areas, easy surface modification, low toxicity, etc., and are applied in multiple fields such as biological separation, resonance imaging, hyperthermia, cell tracing, drug targeted therapy, etc. The preparation of novel functionalized nanomaterials and their composites is a major research hotspot in this field currently.

[0003] Common preparation methods of magnetic nanomaterials include thermal decomposition method, microemulsion method, coprecipitation method, etc. Magnetic nanoparticles synthesized by the microemulsion method and the coprecipitation method usually have characteristics such as large particle size (20 - 160 nm) and poor dispersibility, which are not conducive to surface modification and application of the nanoparticles. Magnetic nanoparticles synthesized by the thermal decomposition method have the advantages of small particle size (4 - 20 nm) and good dispersibility, but the surface of such magnetic nanoparticles is usually difficult to be surface-modified, which limits the application scope of magnetic nanoparticles to a certain extent.

[0004] Magnetic ionic liquids have received more and more attention due to their advantages such as wide suitable temperature range, good chemical stability, green and pollution-free, and strong magnetic response under an external magnetic field, and are mostly used in aspects such as catalysts and extractants.

[0005] The coating of metal Au can improve the biocompatibility, stability, dispersibility, etc. of magnetic nanoparticles to a certain extent, and can change the surface charge, functional groups, reaction characteristics, etc. of the nanoparticles through Au - S bonds. However, due to the diamagnetism of metal Au itself, the magnetic permeability of magnetic nanoparticles decreases significantly under the coating of Au, and even shows diamagnetic properties as the thickness of the Au layer increases.

[0006] Based on the above, there is currently no prior art research on magnetic ionic liquid-modified nanoparticles with a magnetic core-shell structure. Summary of the Invention

[0007] Therefore, the object of the present invention is to overcome the defects in the prior art and provide a magnetic ionic liquid-modified nanoparticle, a preparation method thereof, and an application thereof. By introducing a magnetic ionic liquid as a surface ligand, the present invention can enhance its magnetic permeability by 5 - 100 times, which is beneficial to control by an external magnetic field.

[0008] Before elaborating the content of the present invention, the terms used herein are defined as follows:

[0009] The term "TMA" refers to: N,N,N-trimethyl(11-mercaptoundecyl)ammonium chloride.

[0010] The term "MILs" refers to: magnetic ionic liquids.

[0011] To achieve the above object, a first aspect of the present invention provides a magnetic ionic liquid-modified nanoparticle, the magnetic ionic liquid-modified nanoparticle having a magnetic core-shell structure, and the modification material on the shell surface being a magnetic ionic liquid; wherein, in the magnetic core-shell structure:

[0012] The core is selected from one or more of the following: Fe 3 O 4 , Fe, Co, and most preferably Fe 3 O 4 ; and / or

[0013] The shell layer is Au or Ag, and most preferably Au.

[0014] For the magnetic ionic liquid-modified nanoparticle according to the first aspect of the present invention, wherein the magnetic ionic liquid is prepared by a coordination reaction of an anion and a metal salt, wherein,

[0015] The anion is selected from one or more of the following: Dy(NO 3 ) 4 - , DyCl 4 - , Fe(NO 3 ) 4 - , FeCl 4 - , preferably Dy(NO 3 ) 4 - or DyCl 4 - , and most preferably Dy(NO 3 ) 4 - ; and / or

[0016] The metal salt is N,N,N-trimethyl(11-mercaptoundecyl)ammonium chloride.

[0017] For the magnetic ionic liquid-modified nanoparticle according to the first aspect of the present invention, wherein,

[0018] The particle size of the magnetic ionic liquid-modified nanoparticle is 5 nm to 15 nm, preferably 6 nm to 12 nm, and more preferably 8 nm to 11 nm; and / or

[0019] The magnetic ionic liquid is a quaternary ammonium magnetic ionic liquid.

[0020] The second aspect of the present invention provides a method for preparing the magnetic ionic liquid-modified nanoparticles described in the first aspect, and the method includes: synthesizing magnetic nanoparticles, coating a shell layer on the surface of the obtained magnetic nanoparticles to obtain magnetic core-shell structured nanoparticles, and then adding the magnetic core-shell structured magnetic nanoparticles into the prepared magnetic ionic liquid for reaction to obtain the magnetic ionic liquid-modified nanoparticles;

[0021] Preferably, the method for synthesizing the magnetic nanoparticles is pyrolysis or organic phase synthesis, and most preferably pyrolysis.

[0022] According to the method of the second aspect of the present invention, wherein the method includes the following steps:

[0023] (1) Preparing magnetic nanoparticles: dissolving an iron precursor in a high-boiling solvent, then adding a high-boiling reducing agent, removing the low-boiling solvent, and heating to reflux to obtain oil-soluble magnetic nanoparticles;

[0024] (2) Preparing magnetic core-shell structured nanoparticles: mixing the magnetic nanoparticles prepared in step (1) with a high-boiling solvent, an Au component, and a high-boiling reducing agent, stirring vigorously, heating to reflux, adding ethanol to the solution after the reaction ends for washing and precipitation, and finally dispersing in a non-polar solvent;

[0025] (3) Preparing magnetic ionic liquid: dissolving a quaternary ammonium salt chloride containing a mercapto group in an alcohol, and performing anion replacement, taking the supernatant and adding an alcohol solution of a magnetic substance compound, stirring and removing the solvent, washing and drying to obtain a magnetic ionic liquid; and

[0026] (4) Preparing magnetic ionic liquid-modified nanoparticles: dissolving the magnetic ionic liquid prepared in step (3) and the magnetic core-shell structured nanoparticles prepared in step (2) in a solvent and mixing, stirring and reacting, and removing the supernatant to obtain the magnetic ionic liquid-modified nanoparticles.

[0027] According to the method of the second aspect of the present invention, wherein in step (1):

[0028] The iron precursor is selected from one or more of the following: iron acetylacetonate, iron oleate, ferric chloride hexahydrate, ferric nitrate nonahydrate, ferrous chloride tetrahydrate, preferably selected from one or more of the following: iron acetylacetonate, iron oleate, and more preferably iron acetylacetonate or iron oleate;

[0029] The high-boiling solvent is selected from one or more of the following: toluene, 1-octadecene, diphenyl ether, dimethylformamide, dimethyl sulfoxide, preferably selected from one or more of the following: toluene, 1-octadecene, diphenyl ether, and more preferably 1-octadecene or diphenyl ether;

[0030] The high-boiling-point reducing agent is selected from two or more of the following: 1,2-hexadecanediol, oleylamine, oleic acid, ascorbic acid, sodium borohydride, sodium citrate, preferably from two or more of the following: 1,2-hexadecanediol, oleylamine, oleic acid, and more preferably from two or more of the following: 1,2-hexadecanediol, oleylamine, oleic acid;

[0031] The molar ratio of the iron precursor, the high-boiling-point solvent, and the high-boiling-point reducing agent is 1:50 to 200:1 to 20, preferably 1:50 to 150:1 to 15, and more preferably 1:50 to 100:1 to 10;

[0032] The temperature for removing the low-boiling-point solvent is 100 to 200 °C, preferably 120 to 180 °C, and more preferably 130 to 150 °C;

[0033] The atmosphere for removing the low-boiling-point solvent is nitrogen or argon, and most preferably nitrogen;

[0034] The temperature of the reflux is 200 to 350 °C, preferably 220 to 300 °C, and more preferably 250 to 270 °C; and / or

[0035] The time of the reflux is 2 to 6 h, preferably 3 to 5 h, and more preferably 3 to 4 h.

[0036] According to the method of the second aspect of the present invention, wherein in the step (2):

[0037] The particle size of the magnetic core-shell structured nanoparticles is 5 nm to 15 nm, preferably 6 nm to 12 nm, and more preferably 8 nm to 11 nm;

[0038] The high-boiling-point solvent and the high-boiling-point reducing agent are the same as those in the high-boiling-point solvent and high-boiling-point reducing agent in the step (1);

[0039] The Au component is chloroauric acid or gold acetate, and most preferably gold acetate;

[0040] The molar ratio of the magnetic nanoparticles to the Au component is 1:5 to 20, preferably 1:5 to 15, and more preferably 1:5 to 10;

[0041] The atmosphere for heating up is nitrogen or argon, and most preferably nitrogen;

[0042] The temperature of the reflux is 160 to 200 °C, preferably 170 to 200 °C, and more preferably 180 to 190 °C;

[0043] The time of the reflux is 1 to 4 h, preferably 1 to 3 h, and more preferably 1 to 2 h;

[0044] The volume ratio of the solution after the reaction to the ethanol is 1:2 to 8, preferably 1:2 to 6, more preferably 1:2 to 5;

[0045] During the washing process, the centrifugation speed is 5000 rpm to 10000 rpm, preferably 5000 rpm to 8000 rpm, and most preferably 6000 rpm;

[0046] During the washing process, the centrifugation time is 5 to 15 min, preferably 8 to 12 min, and most preferably 10 min; and / or

[0047] The non-polar solvent is selected from one or more of the following: toluene, n-hexane, dichloromethane, carbon tetrachloride, benzene, preferably selected from one or more of the following: toluene, n-hexane, dichloromethane, and more preferably toluene or n-hexane.

[0048] According to the method of the second aspect of the present invention, wherein in the step (3):

[0049] The quaternary ammonium chloride containing a mercapto group is TMA;

[0050] The alcohol is selected from one or more of the following: methanol, ethanol, n-butanol, isopropanol, preferably methanol or ethanol, and most preferably methanol;

[0051] The anion for anion replacement is NO 3 - or Cl - ;

[0052] The magnetic substance compound is selected from one or more of the following: Dy(NO 3 ) 3 , DyCl 3 , Fe(NO 3 ) 3 , FeCl 3 , preferably Dy(NO 3 ) 3 or DyCl 3 , most preferably Dy(NO 3 ) 3 ;

[0053] The molar ratio of the anion for anion replacement, the quaternary ammonium chloride containing a mercapto group to the magnetic substance compound is 1 to 5:1 to 5:1 to 5, preferably 1 to 3:1 to 3:1 to 3, and most preferably 1:1:1;

[0054] The stirring time is 12 to 48 h, preferably 12 to 36 h, and most preferably 24 h;

[0055] The method for removing the solvent is vacuum rotary distillation; and / or

[0056] The solvent for washing is selected from one or more of the following: diethyl ether, n-propyl ether, n-butyl ether, tetrahydrofuran, preferably selected from one or more of the following: diethyl ether, n-propyl ether, and most preferably diethyl ether.

[0057] According to the method of the second aspect of the present invention, wherein in the step (4):

[0058] The mass ratio of the magnetic ionic liquid to the magnetic core-shell structured nanoparticles is 1:0.5 - 5, preferably 1:0.5 - 3, and more preferably 1:0.5 - 2;

[0059] The solvent is selected from one or more of the following: dichloromethane, n-hexane, toluene, preferably dichloromethane or n-hexane; and / or

[0060] The stirring reaction time is 1 - 3 h, preferably 1 - 2 h, and most preferably 1 h.

[0061] The third aspect of the present invention provides the use of the magnetic ionic liquid-modified nanoparticles described in the first aspect or the magnetic ionic liquid-modified nanoparticles prepared according to the method described in the second aspect in the preparation of materials or products for biological separation, resonance imaging, hyperthermia, cell tracing, and / or drug targeted therapy.

[0062] According to a specific embodiment of the present invention, the overall preparation steps and key process conditions are designed, including:

[0063] (1) Preparation of magnetic nanoparticles: Dissolve an iron precursor in a high-boiling-point solvent, then add a high-boiling-point reducing agent, remove the low-boiling-point solvent at 120 - 150 °C in a nitrogen environment, and then raise the temperature to the set temperature for reflux to obtain oil-soluble magnetic nanoparticles;

[0064] (2) Preparation of magnetic core-shell structured nanoparticles: Take the magnetic nanoparticles and add a high-boiling-point solvent, Au component, and a high-boiling-point reducing agent, raise the temperature to the set temperature for reflux under vigorous stirring and a nitrogen atmosphere, add an appropriate amount of ethanol for precipitation and washing after the reaction, and finally disperse in a non-polar solvent;

[0065] (3) Preparation of magnetic ionic liquid: Dissolve a quaternary ammonium salt containing a mercapto group in alcohol, and perform anion replacement using a salt containing a specific anion. Take the supernatant and add an alcohol solution of a magnetic substance compound, stir and react at room temperature for 24 h, remove the solvent from the obtained solution by vacuum rotary evaporation, wash three times with a poor solvent and dry to obtain a magnetic ionic liquid;

[0066] (4) Preparation of magnetic ionic liquid-modified core-shell structured nanoparticles: Mix the magnetic ionic liquid with Fe 3 O 4@Au is dissolved in a solvent and mixed, and stirred at room temperature for 1 h. After removing the supernatant, magnetic core-shell structured nanoparticles with magnetic ionic liquid as the ligand can be obtained.

[0067] According to the preparation method of the present invention, in step (1), the iron precursor is one or more of iron acetylacetonate and iron oleate; the high-boiling solvent is one or more of solvents such as toluene, octadecene, and diphenyl ether; the high-boiling reducing agent is two or three of 1,2-hexadecanediol, oleylamine, and oleic acid; the reflux temperature is 200-300 °C; the reflux time is 2-4 h; the molar ratio of the iron precursor, the high-boiling solvent, and the high-boiling reducing agent is 1:(50-100):(5-15).

[0068] According to the preparation method of the present invention, in step (2), the Au component is chloroauric acid; the molar ratio of the magnetic nanoparticles to the Au component is 1:(5-10); the reflux temperature is 180-190 °C; the reflux time is 1-2 h; the volume ratio of the original solution to ethanol during washing is 1:(2-5); centrifugation at 6000 rpm during washing is for 10 min; the non-polar solvent is one of toluene, n-hexane, and dichloromethane.

[0069] According to the preparation method of the present invention, in step (3), the quaternary ammonium chloride containing a mercapto group is N,N,N-trimethyl(11-mercaptoundecyl)ammonium chloride, abbreviated as TMA; the alcohols are one or more of methanol, ethanol, n-butanol, and isopropanol; the specific anion is NO 3 - , Cl - in one of them; the compound of the magnetic substance is Dy(NO 3 ) 3 , DyCl 3 , Fe(NO 3 ) 3 , FeCl 3 in one of them; the molar ratio of the replacement anion, TMA, and the compound of the magnetic substance is 1:1:1; the poor solvent is various low-polarity solvents such as diethyl ether.

[0070] According to the preparation method of the present invention, in step (4), the solvent is one of dichloromethane and n-hexane; the mass ratio of MILs to Fe 3 O 4 @Au nanoparticle solution is 1:(0.5-2).

[0071] The magnetic core-shell structured nanoparticles modified with magnetic ionic liquid and the preparation method thereof according to the present invention, the magnetic nanoparticles are based on Fe 3 O 4Using Fe as the core, Au as the shell, and a magnetic ionic liquid as the surface modification material. Its preparation method includes: synthesizing oil-soluble magnetic nanoparticles by thermal decomposition; coating a layer of Au shell on the surface of the obtained dispersed Fe 3 O 4 nanoparticles to obtain Fe 3 O 4 @Au magnetic nanoparticles dispersed in the oil phase; adding an appropriate amount of the prepared magnetic ionic liquid to the Fe 3 O 4 @Au magnetic nanoparticles and reacting to obtain Fe 3 O 4 @Au@MILs magnetic nanoparticles. The present invention can coat and modify the surface of the magnetic nanoparticles obtained by thermal decomposition, combine them with magnetic ionic liquids, and apply them to fields such as microfluidic switches due to their fluid characteristics.

[0072] The magnetic nanoparticle modified with magnetic ionic liquid of the present invention may have but is not limited to the following beneficial effects:

[0073] 1. The Fe 3 O 4 nanoparticles prepared by thermal decomposition usually have the advantages of good dispersibility, small particle size (4nm - 20nm) and controllability, and are easy to be functionalized on their surfaces. In the present invention, by coating a layer of Au on the surface of the Fe 3 O 4 nanoparticles, due to the interaction between Au and groups such as mercapto groups, the possibility of diverse ligand modification on its surface is increased, and the presence of Au further improves the biocompatibility of the magnetic nanoparticles.

[0074] 2. By introducing magnetic ionic liquid as a ligand in the present invention, the magnetic response performance of the magnetic nanoparticles is enhanced, and its magnetic conductivity can be enhanced by 5 - 100 times, which is beneficial to be controlled by an external magnetic field. The final product presents a fluid state similar to that of the magnetic ionic liquid, increasing its application potential in other fluid fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings, where:

[0076] Figure 1 shows the flow chart of the core-shell structured magnetic nanoparticles with magnetic ionic liquid as the ligand prepared in Example 1 of the present invention.

[0077] Figure 2 shows the TEM photograph of the Fe 3 O 4 magnetic nanoparticles prepared in Example 1, and the scale bar is 50nm.

[0078] Figure 3 Shows the Fe prepared in Example 1 3 O 4 Particle size distribution of magnetic nanoparticles

[0079] Figure 4 Shows the Fe prepared in Example 1 3 O 4 TEM image of Fe@Au magnetic nanoparticles prepared in Example 1, scale bar is 50 nm

[0080] Figure 5 Shows the Fe prepared in Example 1 3 O 4 Particle size distribution of Fe@Au magnetic nanoparticles

[0081] Figure 6 Shows the mass spectrum of the magnetic ionic liquid prepared in Example 1; wherein, Figure 6 A shows the mass spectrum peak of the cation of the magnetic ionic liquid (N,N,N-trimethyl(11-mercaptoundecyl)ammonium ion); Figure 6 B shows the mass spectrum peak of the anion of the magnetic ionic liquid

[0082] Figure 7 Shows the Fe prepared in Example 1 3 O 4 Elemental distribution of Au and Dy in Fe@Au@MILs nanoparticles; wherein, Figure 7 A shows the elemental distribution of Au in Fe 3 O 4 @Au@MILs nanoparticles; Figure 7 B shows the elemental distribution of Dy in Fe 3 O 4 @Au@MILs nanoparticles

[0083] Figure 8 Shows the Fe prepared in Example 1 3 O 4 Elemental proportion of Fe@Au@MILs nanoparticles

[0084] Figure 9 Shows the M-H curve of the magnetic nanoparticles prepared in Example 1

[0085] Figure 10 Shows the Fe prepared in Example 2 3 O 4 TEM image of magnetic nanoparticles, scale bar is 50 nm

[0086] Figure 11 Shows the Fe prepared in Example 2 3 O 4 Particle size distribution of magnetic nanoparticles

[0087] Figure 12 Shows the Fe prepared in Example 2 3 O 4 @Au nanoparticle TEM image, scale bar is 100 nm.

[0088] Figure 13 Shows the Fe prepared in Example 2 3 O 4 @Au nanoparticle size distribution.

[0089] Figure 14 Shows the Fe prepared in Example 2 3 O 4 @Au nanoparticles and Fe 3 O 4 @Au@MILs nanoparticle M-H curve. Detailed implementation method

[0090] The present invention will be further described below through specific examples. However, it should be understood that these examples are only used for more detailed and specific illustration, and should not be construed as limiting the present invention in any form.

[0091] This section gives a general description of the materials and test methods used in the experiments of the present invention. Although many of the materials and operation methods used to achieve the purpose of the present invention are well known in the art, the present invention still describes them in as much detail as possible here. Those skilled in the art are aware that, in the context, if not otherwise specified, the materials and operation methods used in the present invention are well known in the art.

[0092] The reagents and instruments used in the following examples are as follows:

[0093] Reagents:

[0094] Iron acetylacetonate, purchased from Alfa Aesar (China) Chemical Co., Ltd.

[0095] Iron oleate and gold acetate, both purchased from Beijing Innochem Science & Technology Co., Ltd.

[0096] 1,2-Hexadecanediol, purchased from Beijing Wokai Biotechnology Co., Ltd.

[0097] Diphenyl ether, oleylamine, oleic acid, dysprosium(III) nitrate hexahydrate, all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0098] Ethanol, ether, toluene, n-hexane, all purchased from Beijing Chemical Works.

[0099] Instruments:

[0100] Lanthanum hexaboride transmission electron microscope, purchased from FEI Company, USA, model: Tecnai G2 20 S-TWIN.

[0101] Liquid chromatography-mass spectrometry LCMS / ESI / QTOF, purchased from Waters Corporation in the United States and Bruker Corporation in Germany, model: UPLC-QTOF.

[0102] Closed-cycle cryogenic system, purchased from Quantum Design in the United States and attocube systems AG in Germany, model: PPMS-ANC300.

[0103] Example 1

[0104] This example is used to illustrate the preparation method of the magnetic ionic liquid-modified core-shell structured magnetic nanoparticles of the present invention.

[0105] Figure 1 The flow chart of the core-shell structured magnetic nanoparticles with magnetic ionic liquid as the ligand prepared in Example 1 of the present invention is shown, and the preparation is carried out according to the Figure 1 flow shown.

[0106] (1) Preparation of Fe 3 O 4 magnetic nanoparticles:

[0107] Take 0.71 g of iron acetylacetonate solid and 2.58 g of 1,2-hexadecanediol, dissolve them in 20 mL of diphenyl ether, add 1.67 mL of oleic acid and 3 mL of oleylamine, and heat the mixture to 210 °C under a nitrogen atmosphere and reflux for 2 h. Cool to room temperature and store for later use. Figure 2 The TEM photograph of the Fe 3 O 4 magnetic nanoparticles prepared in Example 1 is shown. Figure 3 The particle size distribution of the Fe 3 O 4 magnetic nanoparticles prepared in Example 1 is shown. Figure 2 and Figure 3 are respectively the transmission electron micrograph and its particle size distribution of the Fe 3 O 4 magnetic nanoparticles obtained after multiple washing and centrifugation with three times the volume of ethanol in this example, and its particle size is 6.6 nm ± 0.8 nm.

[0108] (2) Preparation of Fe 3 O 4 @Au magnetic nanoparticles:

[0109] Take 10 mL of the solution after the reaction in step (1), add 0.83 g of gold acetate, 3.1 g of 1,2-hexadecanediol, 0.5 mL of oleic acid, and 3 mL of oleylamine dissolved in 30 mL of diphenyl ether, stir vigorously, and under a nitrogen atmosphere, heat to 185 ± 5 °C at a rate of 10 °C / min, react for 1.5 h, and collect the liquid after cooling to room temperature. After washing several times with ethanol, disperse it in 20 mL of n-hexane to obtain Fe 3 O 4 @Au magnetic nanoparticles. Figure 4 Shows the Fe prepared in Example 1 3 O 4 TEM photograph of @Au magnetic nanoparticles. Figure 5 Shows the Fe prepared in Example 1 3 O 4 Particle size distribution of @Au magnetic nanoparticles. Figure 4 and Figure 5 Are respectively the transmission electron micrograph and particle size distribution of the Fe 3 O 4 @Au magnetic nanoparticles synthesized in this example, and their particle size is 9 ± 0.8 nm.

[0110] (3) Preparation of magnetic ionic liquid: Dissolve 0.1 g of TMA in 0.5 mL of methanol, then add 0.0301 g of sodium nitrate, filter off the particulate matter after sufficient shaking. Completely dissolve 0.2002 g of dysprosium chloride hexahydrate in 0.5 mL of methanol and mix it with the ion-exchanged TMA solution, and stir and react at room temperature for 24 h. The resulting solution is evaporated to remove the solvent methanol by vacuum rotary evaporation, washed with 3 mL of diethyl ether, washed multiple times and dried to obtain the magnetic ionic liquid. Figure 6 Shows the mass spectrum of the magnetic ionic liquid prepared in Example 1; among them, Figure 6 A shows the mass spectrum peak of the cation (N,N,N-trimethyl(11-mercaptoundecyl)ammonium ion) of the magnetic ionic liquid; Figure 6 B shows the mass spectrum peak of the anion of the magnetic ionic liquid.

[0111] (4) Preparation of magnetic ionic liquid-modified core-shell structured nanoparticles: Take 1.5 ± 0.5 mL of Fe 3 O 4 @Au n-hexane solution, add 120 mg of magnetic ionic liquid and stir and react for 1 h, and remove the supernatant to obtain magnetic core-shell structured nanoparticles with the fluid magnetic ionic liquid as the ligand. Figure 7 and Figure 8 Are the EDS test results of this nanoparticle. Figure 7 Shows the elemental distribution of Au and Dy in the Fe 3 O 4 @Au@MILs nanoparticles prepared in Example 1. Figure 8Shows the elemental composition of the Fe 3 O 4 @Au@MILs nanoparticles prepared in Example 1.

[0112] Example 2

[0113] This example is used to illustrate the preparation method of the magnetic ionic liquid-modified core-shell structured magnetic nanoparticles of the present invention.

[0114] (1) Preparation of Fe 3 O 4 magnetic nanoparticles:

[0115] Dissolve 3.6 g of iron oleate in a mixture containing 15 mL of oleylamine and 5 mL of oleic acid, stir at 120 °C for 1 h under a nitrogen atmosphere, then raise the temperature to 200 °C and heat under reflux for 2 h, and then raise the temperature to 300 °C again at a rate of 10 °C / 3 min and reflux for 2 h. Collect the product, add three times the volume of ethanol to precipitate and wash the nanoparticles several times to obtain Fe 3 O 4 magnetic nanoparticles with a particle size of 8.2 ± 1.5 nm, dissolved in 4.8 mL of n-hexane for storage.

[0116] (2) Preparation of Fe 3 O 4 @Au magnetic nanoparticles:

[0117] Take 1 mL of the solution after the reaction in step (1), add 0.83 g of chloroauric acid, 3.1 g of 1,2-hexadecanediol, 0.5 mL of oleic acid, and 3 mL of oleylamine, dissolve them in 40 mL of diphenyl ether, stir vigorously, and under a nitrogen atmosphere, raise the temperature to 185 ± 5 °C at a rate of 10 °C / min, react for 1.5 h, and collect the liquid after cooling to room temperature. Wash it several times with ethanol and disperse it in 20 mL of n-hexane to obtain Fe 3 O 4 @Au magnetic nanoparticles with a particle size of 10.7 ± 1.5 nm.

[0118] (3) Preparation of magnetic ionic liquid: Dissolve 0.1 g of TMA in 0.5 mL of methanol, then add 0.0301 g of sodium nitrate, shake well and filter off the particulate matter. Completely dissolve 0.2002 g of dysprosium chloride hexahydrate in 0.5 mL of methanol and mix it with the ion-exchanged TMA solution, stir and react at room temperature for 24 h. The resulting solution is distilled to remove the solvent methanol by vacuum rotary evaporation, washed with 3 mL of ether, washed multiple times and dried to obtain the magnetic ionic liquid.

[0119] (4) Preparation of magnetic ionic liquid-modified core-shell structured nanoparticles: Take 1.5 ± 0.5 mL of Fe 3 O 4Add 120 mg of magnetic ionic liquid to the @Au n-hexane solution and stir for 1 h. Remove the supernatant to obtain magnetic core-shell structured nanoparticles with fluid magnetic ionic liquid as the ligand.

[0120] Figure 10 Shows the Fe prepared in Example 2 3 O 4 TEM photograph of magnetic nanoparticles, with the scale bar being 50 nm. Figure 11 Shows the Fe prepared in Example 2 3 O 4 Particle size distribution of magnetic nanoparticles. Figure 12 Shows the Fe prepared in Example 2 3 O 4 TEM photograph of @Au nanoparticles, with the scale bar being 100 nm. Figure 13 Shows the Fe prepared in Example 2 3 O 4 Particle size distribution of @Au nanoparticles.

[0121] Example 3

[0122] This example is used to illustrate the magnetic properties of the magnetic core-shell structured magnetic nanoparticles modified with magnetic ionic liquid of the present invention.

[0123] Perform magnetic tests on the Fe 3 O 4 nanoparticles, Fe 3 O 4 @Au nanoparticles, and Fe 3 O 4 @Au@MILs nanoparticles at room temperature, as shown in Figure 9 and 14 shown. Figure 9 Shows the M-H curve of the magnetic nanoparticles prepared in Example 1. Figure 14 Shows the Fe prepared in Example 2 3 O 4 @Au nanoparticles and Fe 3 O 4 M-H curves of @Au@MILs nanoparticles.

[0124] For the magnetic core-shell structured magnetic nanoparticles modified with magnetic ionic liquid prepared in Example 1 and Example 2, due to the presence of the Au layer, the coercivity of the nanoparticles decreases significantly but still exhibits ferromagnetic properties, compared with traditional Fe 3 O 4Magnetic nanoparticles have similar properties and can be applied similarly. The presence of Au solves the problem of complex surface functionalization modification of magnetic nanoparticles, improves biocompatibility, expands its application scope, and the introduction of MILs does not change its magnetic properties, while the fluid properties brought by it can be applied to fields such as microfluidic switches.

[0125] Although the present invention has been described to a certain extent, obviously, various appropriate changes can be made without departing from the spirit and scope of the present invention. It is understood that the present invention is not limited to the described embodiments, but falls within the scope of the claims, which include equivalent replacements of each factor described.

Claims

1. A magnetic ionic liquid-modified nanoparticle, characterized in that, the magnetic ionic liquid-modified nanoparticle has a magnetic core-shell structure, and the modifying material on the shell surface is a magnetic ionic liquid; wherein: In the magnetic core-shell structure: the core is selected from one or more of the following: Fe 3 O 4 , Fe, Co; the shell layer is Au or Ag; The magnetic ionic liquid is prepared by a coordination reaction of an anion and a metal salt, wherein: the anion is selected from one or more of the following: Dy(NO 3 ) 4 - , DyCl 4 - , and the metal salt is N,N,N-trimethyl(11-mercaptoundecyl)ammonium chloride; the preparation method of the magnetic ionic liquid includes: dissolving a quaternary ammonium salt chloride containing a mercapto group in an alcohol, performing an anion replacement, taking the supernatant and adding an alcohol solution of a magnetic substance compound, stirring and removing the solvent, washing and drying to obtain the magnetic ionic liquid.

2. The magnetic ionic liquid-modified nanoparticle according to claim 1, characterized in that: The core is Fe 3 O 4 ; and / or the shell layer is Au.

3. The magnetic ionic liquid-modified nanoparticle according to claim 1 or 2, characterized in that, The anion is Dy(NO 3 ) 4 - or DyCl 4 - .

4. The magnetic ionic liquid-modified nanoparticle according to claim 3, characterized in that, The anion is Dy(NO 3 ) 4 - .

5. The magnetic ionic liquid-modified nanoparticle according to claim 1, characterized in that: the particle size of the magnetic ionic liquid-modified nanoparticle is 5 nm to 15 nm; and / or the magnetic ionic liquid is a quaternary ammonium magnetic ionic liquid.

6. The magnetic ionic liquid-modified nanoparticle according to claim 5, characterized in that, the particle size of the magnetic ionic liquid-modified nanoparticle is 6 nm to 12 nm.

7. The magnetic ionic liquid-modified nanoparticle according to claim 6, characterized in that, the particle size of the magnetic ionic liquid-modified nanoparticle is 8 nm to 11 nm.

8. A method for preparing the magnetic ionic liquid-modified nanoparticle according to any one of claims 1 to 7, characterized in that, the method includes: synthesizing magnetic nanoparticles, coating the surface of the prepared magnetic nanoparticles with a shell layer to obtain a magnetic core-shell structured nanoparticle, and then adding the magnetic core-shell structured magnetic nanoparticle to the prepared magnetic ionic liquid for reaction to obtain the magnetic ionic liquid-modified nanoparticle.

9. The method according to claim 8, characterized in that, the method for synthesizing magnetic nanoparticles is pyrolysis or organic phase synthesis.

10. The method according to claim 9, characterized in that, the method for synthesizing magnetic nanoparticles is pyrolysis.

11. The method according to claim 8, characterized in that, the method includes the following steps: (1) Preparing magnetic nanoparticles: dissolving an iron precursor in a high-boiling solvent, then adding a high-boiling reducing agent, removing the low-boiling solvent, and heating to reflux to obtain oil-soluble magnetic nanoparticles; (2) Preparing magnetic core-shell structured nanoparticles: mixing the magnetic nanoparticles prepared in step (1) with a high-boiling solvent, an Au component, and a high-boiling reducing agent, stirring vigorously, heating to reflux, adding ethanol to the solution after the reaction ends for washing and precipitation, and finally dispersing in a non-polar solvent; (3) Preparing magnetic ionic liquid: dissolving a quaternary ammonium salt chloride containing a mercapto group in an alcohol, performing an anion replacement, taking the supernatant and adding an alcohol solution of a magnetic substance compound, stirring and removing the solvent, washing and drying to obtain the magnetic ionic liquid; and (4) Preparation of magnetic ionic liquid-modified nanoparticles: Dissolve the magnetic ionic liquid prepared in step (3) and the magnetic core-shell structured nanoparticles prepared in step (2) in a solvent and mix them, stir and react, and remove the supernatant to obtain the magnetic ionic liquid-modified nanoparticles.

12. According to the method described in claim 11, it is characterized in that in the said step (1): the iron precursor is selected from one or more of the following: iron acetylacetonate, iron oleate, ferric chloride hexahydrate, ferric nitrate nonahydrate, ferrous chloride tetrahydrate; the high-boiling solvent is selected from one or more of the following: toluene, octadecene, diphenyl ether, dimethylformamide, dimethyl sulfoxide; the high-boiling reducing agent is selected from two or more of the following: 1,2-hexadecanediol, oleylamine, oleic acid, ascorbic acid, sodium borohydride, sodium citrate; the molar ratio of the iron precursor, the high-boiling solvent and the high-boiling reducing agent is 1:50-200:1-20; the temperature for removing the low-boiling solvent is 100-200 °C; the atmosphere for removing the low-boiling solvent is nitrogen or argon; the temperature of the reflux is 200-350 °C; and / or the time of the reflux is 2-6 h.

13. According to the method described in claim 12, it is characterized in that in the said step (1): the iron precursor is selected from one or more of the following: iron acetylacetonate, iron oleate; the high-boiling solvent is selected from one or more of the following: toluene, octadecene, diphenyl ether; the high-boiling reducing agent is selected from two or more of the following: 1,2-hexadecanediol, oleylamine, oleic acid, ascorbic acid, sodium borohydride, sodium citrate; the molar ratio of the iron precursor, the high-boiling solvent and the high-boiling reducing agent is 1:50-150:1-15; the temperature for removing the low-boiling solvent is 120-180 °C; the atmosphere for removing the low-boiling solvent is nitrogen; the temperature of the reflux is 220-300 °C; and / or the time of the reflux is 3-5 h.

14. According to the method described in claim 13, it is characterized in that in the said step (1): the iron precursor is iron acetylacetonate or iron oleate; the high-boiling solvent is octadecene or diphenyl ether; the high-boiling reducing agent is selected from two or more of the following: 1,2-hexadecanediol, oleylamine, oleic acid; the molar ratio of the iron precursor, the high-boiling solvent and the high-boiling reducing agent is 1:50-100:1-10; the temperature for removing the low-boiling solvent is 130-150 °C; the temperature of the reflux is 250-270 °C; and / or the time of the reflux is 3-4 h.

15. According to the method described in claim 11, it is characterized in that in the said step (2): the particle size of the magnetic core-shell structured nanoparticles is 5 nm - 15 nm; the high-boiling solvent and the high-boiling reducing agent are the same as those in the high-boiling solvent and high-boiling reducing agent in step (1); the Au component is chloroauric acid or gold acetate; the molar ratio of the magnetic nanoparticles to the Au component is 1:5-20; the atmosphere for heating up is nitrogen or argon; the temperature of the reflux is 160-200 °C; The time of the reflux is 1 to 4 h; The volume ratio of the solution after the reaction ends to the ethanol is 1:2 to 8; The rotation speed of centrifugation during the washing process is 5000 rpm to 10000 rpm; The time of centrifugation during the washing process is 5 to 15 min; and / or The non-polar solvent is selected from one or more of the following: toluene, n-hexane, dichloromethane, carbon tetrachloride, benzene.

16. According to the method described in claim 15, it is characterized in that in the step (2): the particle size of the magnetic core-shell structured nanoparticles is 6 nm to 12 nm; the Au component is chloroauric acid; the molar ratio of the magnetic nanoparticles to the Au component is 1:5 to 15; the atmosphere for the temperature rise is nitrogen; the temperature of the reflux is 170 to 200 °C; the time of the reflux is 1 to 3 h; the volume ratio of the solution after the reaction ends to the ethanol is 1:2 to 6; the rotation speed of centrifugation during the washing process is 5000 rpm to 8000 rpm; the time of centrifugation during the washing process is 8 to 12 min; and / or the non-polar solvent is selected from one or more of the following: toluene, n-hexane, dichloromethane.

17. According to the method described in claim 16, it is characterized in that in the step (2): the particle size of the magnetic core-shell structured nanoparticles is 8 nm to 11 nm; the molar ratio of the magnetic nanoparticles to the Au component is 1:5 to 10; the temperature of the reflux is 180 to 190 °C; the time of the reflux is 1 to 2 h; the volume ratio of the solution after the reaction ends to the ethanol is 1:2 to 5; the rotation speed of centrifugation during the washing process is 6000 rpm; the time of centrifugation during the washing process is 10 min; and / or the non-polar solvent is toluene or n-hexane.

18. According to the method described in claim 11, it is characterized in that in the step (3): the quaternary ammonium chloride containing a mercapto group is TMA; the alcohol is selected from one or more of the following: methanol, ethanol, n-butanol, isopropanol; The anion for anion replacement is NO 3 - or Cl - ; The magnetic substance compound is selected from one or more of the following: Dy(NO 3 ) 3 , DyCl 3 ; the molar ratio of the anion for the anion replacement, the quaternary ammonium chloride containing a mercapto group to the magnetic substance compound is 1 to 5:1 to 5:1 to 5; the stirring time is 12 to 48 h; the method for removing the solvent is vacuum rotary distillation; and / or the washing solvent is selected from one or more of the following: diethyl ether, n-propyl ether, n-butyl ether, tetrahydrofuran.

19. According to the method described in claim 18, it is characterized in that in the step (3): the alcohol is methanol or ethanol; The magnetic substance compound is Dy(NO 3 ) 3 or DyCl 3 ; the molar ratio of the anion for the anion replacement, the quaternary ammonium chloride containing a mercapto group to the magnetic substance compound is 1 to 3:1 to 3:1 to 3; the stirring time is 12 to 36 h; and / or the washing solvent is selected from: diethyl ether, n-propyl ether.

20. According to the method described in claim 19, it is characterized in that in the step (3): the alcohol is methanol; The magnetic substance compound is Dy(NO 3 ) 3 ; the molar ratio of the anion for the anion replacement, the quaternary ammonium chloride containing a mercapto group to the magnetic substance compound is 1:1:1; The stirring time is 24 h; and / or The solvent for washing is diethyl ether.

21. The method according to claim 11,[[]] wherein in the step (4): the mass ratio of the magnetic ionic liquid to the magnetic core-shell structured nanoparticles is 1:0.5 - 5; the solvent is selected from one or more of the following: dichloromethane, n-hexane, toluene; and / or the stirring reaction time is 1 - 3 h.

22. The method according to claim 21,[[]] wherein in the step (4): the mass ratio of the magnetic ionic liquid to the magnetic core-shell structured nanoparticles is 1:0.5 - 3; the solvent is dichloromethane or n-hexane; and / or the stirring reaction time is 1 - 2 h.

23. The method according to claim 22,[[]] wherein in the step (4): the mass ratio of the magnetic ionic liquid to the magnetic core-shell structured nanoparticles is 1:0.5 - 2; and / or the stirring reaction time is 1 h.

24. Use of the nanoparticles modified with magnetic ionic liquid according to any one of claims 1 to 7 or the nanoparticles modified with magnetic ionic liquid prepared by the method according to any one of claims 8 to 23 in the preparation of materials or products for biological separation, resonance imaging, hyperthermia, cell tracing and / or drug targeted therapy.

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