Multifunctionalized magnetic silica microspheres prepared based on inverse emulsion method, preparation method and application thereof
The reverse emulsion method for preparing micron-sized magnetic silica microspheres solves the problem of difficulty in preparing and functionalizing micron-sized magnetic silica microspheres in existing technologies, and realizes a simple and multifunctional preparation method suitable for bioconjugation and industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANSHAN UNIV
- Filing Date
- 2023-08-30
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies struggle to prepare magnetic silica microspheres at the micrometer and tens of micrometer scales, and the limited number of surface functional groups makes them unsuitable for practical applications. Furthermore, the complex preparation methods make them unsuitable for industrial production.
Micron-sized magnetic silica microspheres were prepared using a reverse emulsion method. Fe3O4 magnetic particles were used as the core, and the silica was encapsulated and amino, hydroxyl, carboxyl or vinyl functional groups were grafted onto its surface. This simplified the preparation process and enabled multifunctionality.
The preparation method is simple, and it can graft abundant functional groups on the surface of microspheres. It is suitable for biocoupled proteins and streptavidin. The particle size is controllable and it is suitable for industrial production.
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Figure CN117123152B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of magnetic material preparation technology, specifically involving the preparation of micron-sized magnetic silica microspheres using the reverse emulsion method and the subsequent functionalization modification. Background Technology
[0002] Functionalized magnetic materials, which integrate the advantages of magnetic materials and nanomaterials, are among the most promising materials. They can be endowed with different functions to meet various needs and have been widely used in industrial fields such as high-density magnetic data storage arrays, magneto-optical switches, and sensors, as well as in biological and medical fields such as magnetic resonance imaging (MRI) contrast agents, oligonucleotides, separation of cells and biological components, and immobilization of proteins and enzymes. Among these, magnetic silica microspheres are particularly interesting because silica's remarkable properties provide high chemical and thermal stability and excellent biocompatibility, expanding its application range.
[0003] Many magnetic silica microspheres have been reported, but most of them have few surface functionalization groups, making them difficult to apply in practice. Furthermore, the preparation methods are complex, and most magnetic silica microspheres are limited to the nanoscale, with very few reports on micrometer-sized or tens of micrometer-sized magnetic silica microspheres. Therefore, this application provides a method for preparing micrometer-sized and tens of micrometer-sized magnetic silica microspheres that can be surface functionalized with various groups without distribution treatment. These microspheres can be used for biomolecules such as coupling proteins, streptavidin, and antibodies. The preparation method is simple and suitable for industrial production. Summary of the Invention
[0004] To address the shortcomings of the existing technologies, the present invention aims to design and provide a method for preparing micron-sized magnetic silica microspheres based on a reverse emulsion method, and a method applicable to the functionalization of various functional groups, for use in biocoupled proteins and streptavidin, etc. This invention uses Fe3O4 magnetic particles as the magnetic component, and utilizes a water-in-oil reverse emulsion to coat the surface of the Fe3O4 magnetic particles with a layer of silica. By changing the proportions, microspheres of different micron sizes are obtained. Amino and vinylsilane silane compounds and halogenated hydrocarbon carboxylic acid compounds are used as functionalizing reagents. No stepwise processing is required; by adding the appropriate substances during the reaction, a large number of hydroxyl, amino, carboxyl, and vinyl functional groups can be grafted onto the surface of the microspheres.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] On the one hand, the present invention provides a multifunctional micron-sized magnetic silica microsphere prepared by the reverse emulsion method, comprising Fe3O4 magnetic particles, silica coated on the surface of Fe3O4 magnetic particles, and functional groups grafted on the surface of silica.
[0007] The multifunctional micron-sized magnetic silica microspheres prepared by the reverse emulsion method are described above, wherein the functional groups include one of hydroxyl, amino, carboxyl or vinyl groups; and the particle size of the multifunctional micron-sized magnetic silica microspheres is 3μm-70μm.
[0008] Secondly, the present invention provides a method for preparing multifunctional micron-sized magnetic silica microspheres based on the reverse emulsion method, comprising the following steps:
[0009] (1) Weigh Fe3O4 magnetic particles, disperse them in an inorganic strong acid solution, mix them evenly, maintain the temperature and rotation speed to form an acidic magnetic fluid, add fatty acid ester compounds that are soluble in oil-phase alkane solvents, stir, add tetraethyl orthosilicate dropwise, and carry out the reaction.
[0010] (2) Wash with ethanol and water alternately, and dry to obtain hydroxyl-functionalized magnetic silica microspheres;
[0011] Alternatively, (3) add a monohydric alcohol compound and continue the reaction for 1.5 h, add an aminosilane compound dropwise and continue the reaction for 4 h, wash with ethanol and water alternately, dry, and obtain amino-functionalized magnetic silica microspheres.
[0012] Alternatively, (4) add a monohydric alcohol compound, continue the reaction for 1.5 h, add an aminosilane compound and a haloalkanes carboxylic acid compound, mix and stir, continue the reaction, wash with ethanol and water alternately, dry, and obtain carboxyl-functionalized magnetic silica microspheres.
[0013] Alternatively, (5) add a monohydric alcohol compound and continue the reaction for 1.5 h, then add a vinyl silane compound and continue the reaction for 4 h, wash with ethanol and water alternately, and dry to obtain vinyl-functionalized magnetic silica microspheres.
[0014] In the preparation method described above, the temperature and rotation speed in step (1) are specifically as follows: temperature 40-45℃, rotation speed 500-1800rpm; the stirring time is 10min, and the reaction time is 0.5-6h.
[0015] The inorganic strong acid solution is selected from one of nitric acid, sulfuric acid, hydrochloric acid, and hydrobromic acid; the concentration of the inorganic strong acid solution is 0.075M-2M.
[0016] The mass-to-volume ratio of the Fe3O4 magnetic particles to the oil-phase alkane solvent is 0.0088:1 to 0.0352:1 g / mL.
[0017] In the preparation method described above, the oil phase alkane solvent in step (1) is selected from one of the alkanes or cycloalkanes that are insoluble in water, preferably one of hexaane, cyclohexane, heptane, octane or octadecane;
[0018] The fatty acid ester compound is selected from one of the following: glyceryl monostearate, polyethylene glycol (200) monolaurate, polyethylene glycol (200) dilaurate, sorbitol fatty acid ester, or sorbitan trioleate.
[0019] The mass-to-volume ratio of the fatty acid ester compound to the oil phase alkane solvent is 0.001:1 to 0.01:1 g / mL;
[0020] The volume ratio of the inorganic strong acid solution to the oil phase alkane solvent is 0.01:1 to 0.05:1;
[0021] The volume ratio of the tetraethyl orthosilicate to the oil phase alkane solvent is 1:27 to 4:27.
[0022] In the preparation method described above, the monohydric alcohol compound in step (3) is selected from one of n-butanol, n-pentanol, n-hexanol, or cetyl alcohol; the aminosilane compound is selected from 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane.
[0023] The mass-to-volume ratio of the monohydric alcohol compound to the oil-phase alkane solvent is 0.000037:1 to 0.0046:1;
[0024] The volume ratio of the aminosilane compound to the oil phase alkane solvent is 0.0074:1 to 0.12:1.
[0025] In the preparation method described above, the haloalkanes carboxylic acid compound in step (4) is a compound containing one of chlorine, bromine or carboxylic acid groups, preferably selected from chloroacetic acid, sodium bromoacetate, 3-chloropropionic acid, 3-bromopropionic acid, α-bromoisobutyric acid or sodium chloroacetate;
[0026] The mass-to-volume ratio of the haloalkanes carboxylic acid compound to the oil-phase alkane solvent is 0.015:1 to 12:13 g / mL.
[0027] In the preparation method described above, the vinyl silane compound in step (5) is selected from one of γ-methacryloyloxypropyltrimethoxysilane (KH570), vinyltriethoxysilane, or vinyltrimethoxysilane;
[0028] The volume ratio of the vinyl silane compound to the oil phase alkane solvent is 0.0074:1 to 0.12:1.
[0029] The preparation method described above is characterized in that the preparation method of the Fe3O4 magnetic particles includes:
[0030] Weigh out FeCl36H2O and Fe(NH4)2(SO4)27H2O and dissolve them in water. Stir and heat to 50-60℃. Add PEG8000 and stir to react. Add ammonia water and heat to continue the reaction. Stop stirring and let stand. Cool to room temperature and perform magnetic separation. Wash to obtain Fe3O4 magnetic particles.
[0031] Preferably, the mass ratio of FeCl36H2O to Fe(NH4)2(SO4)27H2O is 0.27:1 to 0.9:1;
[0032] The stirring reaction time is 10 min; the temperature is raised to 80℃, the reaction time is 15 min, and the settling time is 1-1.5 h.
[0033] Thirdly, the present invention provides the application of the multifunctional micron-sized magnetic silica microspheres prepared by the reverse emulsion method as immunoglobulins and streptavidin microspheres.
[0034] Compared with the prior art, the present invention has the following beneficial effects:
[0035] 1. The method for preparing magnetic silica microspheres by the present invention is simple, batch-stable, and controllable. It does not require step-by-step processing. By adding the corresponding substances during the reaction, magnetic silica microspheres modified with hydroxyl, amino, carboxyl and vinyl groups can be prepared.
[0036] 2. The present invention can obtain microspheres of 3μm-70μm size by changing the ratio of fatty acid ester compounds and monohydric alcohol compounds and the stirring rate.
[0037] 3. The multifunctional micron-sized magnetic silica microspheres of the present invention contain abundant functional groups on their surface, and the carboxyl microspheres can also be stably bound to proteins, exhibiting a high protein coupling rate. They can be used for biological protein coupling, separation, and sensing technologies. Attached Figure Description
[0038] Figure 1 This is a scanning electron microscope (SEM) schematic diagram of the magnetic silica hydroxyl microspheres prepared in Example 1;
[0039] Figure 2 This is a scanning electron microscope (SEM) schematic diagram of the magnetic silica amino microspheres prepared in Example 2;
[0040] Figure 3 The infrared spectrum of the magnetic silica amino microspheres prepared in Example 2;
[0041] Figure 4This is a scanning electron microscope (SEM) schematic diagram of the magnetic silica carboxyl microspheres prepared in Example 3;
[0042] Figure 5 The scanning infrared spectrum of the magnetic silica carboxyl microspheres prepared in Example 3;
[0043] Figure 6 A schematic diagram of an optical microscope (X100) for the magnetic silica vinyl microspheres prepared in Example 4;
[0044] Figure 7 The scanning infrared spectrum of the magnetic silica vinyl microspheres prepared in Example 4;
[0045] Figure 8 A schematic diagram of an optical microscope (X400) for the magnetic silica carboxyl microspheres prepared in Example 5;
[0046] Figure 9 This is a scanning electron microscope (SEM) schematic diagram of the magnetic silica carboxyl microspheres prepared in Example 6. Detailed Implementation
[0047] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. However, those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0048] Example 1:
[0049] This embodiment 1 provides a multifunctional micron-sized magnetic silica microsphere prepared by a reverse emulsion method, the preparation method of which includes:
[0050] (1) Preparation of Fe3O4 magnetic particles: Weigh 2g FeCl3·6H2O and 2.5g Fe(NH4)2(SO4)2·7H2O and dissolve them in 50mL of water. Heat to 56℃, add 0.2g PEG-8000, stir at 330rpm for 10min, then add 30mL of ammonia water, heat to 80℃ and react for 15min. Stop stirring and let stand for 1.5h. After the reaction is complete, use a magnet for magnetic separation, wash with deionized water and ethanol alternately several times to remove reaction residues and byproducts, and store in deionized water to obtain superparamagnetic Fe3O4 magnetic particles.
[0051] (2) Preparation of magnetic silica hydroxyl microspheres: Weigh 0.38g of the Fe3O4 magnetic particles prepared in step (1) and disperse them in 0.6mL of 0.2M sulfuric acid solution. After mixing evenly, place the mixture into a reaction flask and maintain a temperature of 40℃ and a rotation speed of 500rpm.
[0052] 27 mL of hexane solution containing 0.14 g glyceryl monostearate was added to the flask, stirred for 10 min, and then 2.4 mL of tetraethyl orthosilicate was added dropwise. After reacting for 6 h, magnetic separation was performed. The mixture was washed three times alternately with ethanol and water, and dried at 37 °C for 24 h to obtain magnetic silica hydroxyl microspheres with a particle size of 15-20 μm. Scanning electron microscopy showed the following results. Figure 1 As shown.
[0053] Example 2:
[0054] This embodiment 2 provides a multifunctional micron-sized magnetic silica microsphere prepared by a reverse emulsion method, the preparation method of which includes:
[0055] (1) Preparation of Fe3O4 magnetic particles: Weigh 2g FeCl3·6H2O and 2.5g Fe(NH4)2(SO4)2·7H2O and dissolve them in 50mL of water. Heat to 56℃, add 0.2g PEG-8000, stir at 330rpm for 10min, then add 30mL of ammonia water, heat to 80℃ and react for 15min. Stop stirring and let stand for 1.5h. After the reaction is complete, use a magnet for magnetic separation, wash with deionized water and ethanol alternately several times to remove reaction residues and byproducts, and store in deionized water to obtain superparamagnetic Fe3O4 magnetic particles.
[0056] (2) Preparation of magnetic silica amino microspheres: 0.45 g of the Fe3O4 magnetic particles prepared in step (1) were weighed and dispersed in 0.4 mL of 0.25 M nitric acid solution. After mixing evenly, the mixture was placed in a reaction flask and kept at 40 °C and 500 rpm. 27 mL of cyclohexane solution containing 0.028 g of polyethylene glycol (200) monolaurate was added to the flask and stirred for 10 min. 2.4 mL of tetraethyl orthosilicate was added dropwise, and the reaction was allowed to proceed for 0.5 h. 0.002 g of cetyl alcohol was added, and the reaction was allowed to continue for 1.5 h. 3 mL of 3-aminopropyltriethoxysilane was added dropwise, and the reaction was allowed to continue for 4 h. The microspheres were washed three times with alternating ethanol and water, and dried at 37 °C for 24 h to obtain magnetic silica amino microspheres. The potential was measured to be +25 mV, and the particle size was approximately 10-20 μm. The scanning electron microscope results are as follows: Figure 2 As shown, the infrared spectrum is as follows Figure 3 As shown.
[0057] Example 3:
[0058] This embodiment 3 provides a multifunctional micron-sized magnetic silica microsphere prepared by a reverse emulsion method, the preparation method of which includes:
[0059] (1) Preparation of Fe3O4 magnetic particles: Weigh 2g FeCl3·6H2O and 2.5g Fe(NH4)2(SO4)2·7H2O and dissolve them in 50mL of water. Heat to 56℃, add 0.2g PEG-8000, stir at 330rpm for 10min, then add 30mL of ammonia water, heat to 80℃ and react for 15min. Stop stirring and let stand for 1.5h. After the reaction is complete, use a magnet for magnetic separation, wash with deionized water and ethanol alternately several times to remove reaction residues and byproducts, and store in deionized water to obtain superparamagnetic Fe3O4 magnetic particles.
[0060] (2) Preparation of magnetic silica carboxyl microspheres: Weigh 0.38g of the Fe3O4 magnetic particles prepared in step (1) and disperse them in 0.5mL of 0.3M hydrochloric acid solution. After mixing evenly, place the mixture in a reaction flask and maintain a temperature of 45℃ and a rotation speed of 500rpm.
[0061] 27 mL of a heptane solution containing 0.084 g of polyethylene glycol (200) monolaurate was added to a flask and stirred for 10 min. Then, 2.4 mL of tetraethyl orthosilicate was added dropwise, and the reaction was allowed to proceed for 0.5 h. Afterward, 0.006 g of n-pentanol was added, and the reaction was continued for another 1.5 h. Then, 1.5 mL of 3-aminopropyltriethoxysilane and 0.8 g of bromoacetic acid were added, and the reaction was continued for another 4 h. The mixture was washed three times alternately with ethanol and water, and dried at 37 °C for 24 h to obtain magnetic silica carboxyl microspheres. The particle size was 20-40 μm, and their scanning electron microscopy results were as follows: Figure 4 As shown, the infrared spectrum is as follows Figure 5 As shown.
[0062] Example 4:
[0063] Example 4 provides a multifunctional micron-sized magnetic silica microsphere prepared by a reverse emulsion method, the preparation method of which includes:
[0064] (1) Preparation of Fe3O4 magnetic particles: Weigh 2g FeCl3·6H2O and 2.5g Fe(NH4)2(SO4)2·7H2O and dissolve them in 50mL of water. Heat to 56℃, add 0.2g PEG-8000, stir at 330rpm for 10min, then add 30mL of ammonia water, heat to 80℃ and react for 15min. Stop stirring and let stand for 1.5h. After the reaction is complete, use a magnet for magnetic separation, wash with deionized water and ethanol alternately several times to remove reaction residues and byproducts, and store in deionized water to obtain superparamagnetic Fe3O4 magnetic particles.
[0065] (2) Preparation of magnetic silica vinyl microspheres: Weigh 0.38g of the Fe3O4 magnetic particles prepared in step (1) and disperse them in 0.6mL of 0.2M nitric acid solution. After mixing evenly, place the mixture into a reaction flask and maintain a temperature of 40℃ and a rotation speed of 600rpm.
[0066] Add 27 mL of hexane solution containing 0.028 g of dehydrated sorbitol fatty acid ester to the flask, stir for 10 min, add 2.4 mL of tetraethyl orthosilicate dropwise, and after 0.5 h, add 25 μl of n-butanol, react for 1.5 h, add 1.5 mL of vinyltriethoxysilane dropwise, and continue the reaction for 4 h. Wash three times alternately with ethanol and water, and dry at 37 °C for 24 h to obtain magnetic silica vinyl microspheres. Optical microscope images are shown below. Figure 6 Infrared spectrum, such as Figure 7 .
[0067] Example 5:
[0068] Example 5 provides a multifunctional micron-sized magnetic silica microsphere prepared by a reverse emulsion method, the preparation method of which includes:
[0069] (1) Preparation of Fe3O4 magnetic particles: Weigh 2g FeCl3·6H2O and 2.5g Fe(NH4)2(SO4)2·7H2O and dissolve them in 50mL of water. Heat to 56℃, add 0.2g PEG-8000, stir at 330rpm for 10min, then add 30mL of ammonia water, heat to 80℃ and react for 15min. Stop stirring and let stand for 1.5h. After the reaction is complete, use a magnet for magnetic separation, wash with deionized water and ethanol alternately several times to remove reaction residues and byproducts, and store in deionized water to obtain superparamagnetic Fe3O4 magnetic particles.
[0070] (2) Preparation of magnetic silica carboxyl microspheres: Weigh 0.38g of the Fe3O4 magnetic particles prepared in step (1) and disperse them in 0.3mL of 0.8M hydrochloric acid solution. After mixing evenly, place the mixture in a reaction flask and maintain the temperature at 40℃ and a rotation speed of 1800rpm. Add 27mL of octadecane solution containing 0.14g of polyethylene glycol (200) monolaurate to the flask and stir for 10min. Add 2.4mL of tetraethyl orthosilicate and stir for 10min. Add 0.01g of n-pentanol and continue the reaction for 1.5h. Add 3mL of 3-aminopropyltrimethoxysilane and 1.56g of chloroacetic acid and continue the reaction for 6h. Wash the mixture three times with alternating ethanol and water and dry it at 37℃ for 24h to obtain magnetic silica carboxyl microspheres with a particle size of 3-6μm. The optical microscope image (X400) is shown below. Figure 8 As shown.
[0071] Example 6:
[0072] This embodiment 6 provides a multifunctional micron-sized magnetic silica microsphere prepared by a reverse emulsion method, the preparation method of which includes:
[0073] (1) Preparation of Fe3O4 magnetic particles: Weigh 2g FeCl3·6H2O and 2.5g Fe(NH4)2(SO4)2·7H2O and dissolve them in 50mL of water. Heat to 56℃, add 0.2g PEG-8000, stir at 330rpm for 10min, then add 30mL of ammonia water, heat to 80℃ and react for 15min. Stop stirring and let stand for 1.5h. After the reaction is complete, use a magnet for magnetic separation, wash with deionized water and ethanol alternately several times to remove reaction residues and byproducts, and store in deionized water to obtain superparamagnetic Fe3O4 magnetic particles.
[0074] (2) Preparation of magnetic silica carboxyl microspheres: Weigh 0.55g of the Fe3O4 magnetic particles prepared in step (1) and disperse them in 0.6mL of 0.2M sulfuric acid solution. After mixing evenly, place the mixture in a reaction flask and maintain a temperature of 40℃ and a rotation speed of 500rpm. Add 27mL of octane solution containing 0.28g of polyethylene glycol (200) dilaurate to the flask and stir for 10min. Add 2mL of tetraethyl orthosilicate and react for 0.5h. Add 0.02g of n-hexanol and continue the reaction for 1.5h. Add 1mL of 3-aminopropyltrimethoxysilane mixed with 0.5g of 3-chloropropionic acid and continue the reaction for 6h. Wash the mixture three times with alternating ethanol and water, and dry it at 37℃ for 24h to obtain magnetic silica carboxyl microspheres with a particle size of 8-10μm. The scanning electron microscope results are shown in Figure 1. Figure 9 As shown.
[0075] Example 7:
[0076] Method for activating carboxyl magnetic microspheres: Place 0.03g of magnetic beads in a 2mL centrifuge tube, wash three times with 200μL of MES (2-morpholinoethanesulfonic acid) buffer, perform magnetic separation, remove the supernatant, first add 200μL of ultrapure water to prepare 50mg / mL EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) solution, mix well, then add 200μL of ultrapure water to prepare NHS (N-hydroxysuccinimide) solution, mix well, incubate at room temperature for 30min, after which place on a magnetic rack for 3min adsorption, discard the supernatant, and wash three times with 200μL of MES solution to obtain activated carboxyl magnetic microspheres.
[0077] Activated magnetic microspheres coupled with protein: Take 1 mL of 0.5 mg / mL BSA (bovine serum albumin) solution prepared with ultrapure water, add it to the activated magnetic beads, incubate at 37℃ for 30 min, use the BCA kit to determine the protein concentration in the supernatant after protein coupling, and calculate the protein coupling amount of the magnetic microspheres.
[0078] Activated magnetic microspheres coupled with streptavidin: Take 0.015 g of activated magnetic carboxyl microspheres, wash three times with 200 μL of MES (2-morpholinoethanesulfonic acid) buffer, magnetically separate, remove the supernatant, disperse in 300 μL of PBS buffer, add 10 μL of 5 mg / ml streptavidin solution, incubate at room temperature for 30 min, and magnetically separate to obtain streptavidin-conjugated magnetic microspheres.
[0079] Antibody conjugation with activated magnetic microspheres: Take 0.03g of activated magnetic carboxyl microspheres, wash three times with 200μL of MES (2-morpholinoethanesulfonic acid) buffer, magnetically separate, remove the supernatant, add 200μL of 2mg / mL antibody solution, incubate at room temperature for 30min, and magnetically separate to obtain immunomagnetic microspheres.
[0080] The performance of the magnetic silica carboxyl microspheres provided in Example 5 of this invention was tested and compared with magnetic beads from three well-known domestic and foreign companies (Westcomb Biotechnology Co., Ltd., product number: MA600H; Thermo Fisher Scientific, product number: 21353; Dynal, product number: 65305). The results are shown in Table 1.
[0081] Table 1. Performance Comparison of Magnetic Silica Microspheres
[0082]
[0083] As shown in Table 1, compared to magnetic microspheres provided by well-known domestic and international companies, the magnetic silica microspheres provided in this application offer a wider range of particle size options. They can provide magnetic microspheres ranging from a few micrometers to tens of micrometers in size, and can be modified with various functional groups. This results in shorter magnetic separation time (i.e., higher magnetic content) and higher coupling protein efficiency (i.e., higher carboxyl content). Therefore, the magnetic silica carboxyl microspheres prepared in this application exhibit superior performance, shorter magnetic separation time, and are more conducive to operation and large-scale use, resulting in better separation effects.
[0084] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for preparing multifunctional micron-sized magnetic silica microspheres based on a reverse emulsion method, characterized in that, The silica microspheres comprise Fe3O4 magnetic particles, silica coating the surface of the Fe3O4 magnetic particles, and grafted functional groups on the silica surface; the functional groups include one of hydroxyl, amino, carboxyl, or vinyl groups; the particle size of the multifunctional micron-sized magnetic silica microspheres is 3μm-70μm, and the preparation method of the silica microspheres includes the following steps: (1) Weigh Fe3O4 magnetic particles, disperse them in an inorganic strong acid solution, mix them evenly, maintain the temperature and rotation speed to form an acidic magnetic fluid, add fatty acid ester compounds that are soluble in oil phase alkane solvent, stir, add tetraethyl orthosilicate dropwise, and carry out the reaction; (2) Wash with ethanol and water alternately, and dry to obtain hydroxyl-functionalized magnetic silica microspheres; Alternatively, (3) add a monohydric alcohol compound and continue the reaction for 1.5 h, add an aminosilane compound dropwise and continue the reaction for 4 h, wash with ethanol and water alternately, dry, and obtain amino-functionalized magnetic silica microspheres; Alternatively, (4) add monohydric alcohol compounds, continue the reaction for 1.5 h, add aminosilane compounds and haloalkanes carboxylic acid compounds, mix and stir, continue the reaction, wash with ethanol and water alternately, dry, and obtain carboxyl-functionalized magnetic silica microspheres. Alternatively, (5) add a monohydric alcohol compound and continue the reaction for 1.5 h, then add a vinyl silane compound and continue the reaction for 4 h, wash with ethanol and water alternately, and dry to obtain vinyl-functionalized magnetic silica microspheres.
2. The preparation method according to claim 1, characterized in that, The temperature and rotation speed in step (1) are as follows: temperature 40-45℃, rotation speed 500-1800rpm; stirring time is 10min, and reaction time is 0.5-6h. The inorganic strong acid solution is selected from one of nitric acid, sulfuric acid, hydrochloric acid, and hydrobromic acid; the concentration of the inorganic strong acid solution is 0.075M-2M. The mass-to-volume ratio of the Fe3O4 magnetic particles to the oil-phase alkane solvent is 0.0088:1 to 0.0352:1 g / mL.
3. The preparation method according to claim 1, characterized in that, The oil phase alkane solvent mentioned in step (1) is selected from one of the alkanes or cycloalkanes that are insoluble in water; The fatty acid ester compound is selected from one of the following: glyceryl monostearate, polyethylene glycol (200) monolaurate, polyethylene glycol (200) dilaurate, sorbitol fatty acid ester, or sorbitan trioleate. The mass-to-volume ratio of the fatty acid ester compound to the oil phase alkane solvent is 0.001:1 to 0.01:1 g / mL; The volume ratio of the inorganic strong acid solution to the oil phase alkane solvent is 0.01:1 to 0.05:1; The volume ratio of the tetraethyl orthosilicate to the oil phase alkane solvent is 1:27 to 4:
27.
4. The preparation method according to claim 3, characterized in that, The oil phase alkane solvent is selected from one of hexaane, cyclohexane, heptane, octane, or octadecane.
5. The preparation method according to claim 1, characterized in that, The monohydric alcohol compound mentioned in step (3) is selected from one of n-butanol, n-pentanol, n-hexanol or cetyl alcohol; the aminosilane compound is selected from 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane. The mass-to-volume ratio of the monohydric alcohol compound to the oil-phase alkane solvent is 0.000037:1 to 0.0046:1 g / mL; The volume ratio of the aminosilane compound to the oil phase alkane solvent is 0.0074:1 to 0.12:
1.
6. The preparation method according to claim 1, characterized in that, The halohydrocarboxylic acid compound mentioned in step (4) is a compound containing one of chlorine, bromine or carboxylic acid groups, and the halohydrocarboxylic acid compound is selected from one of chloroacetic acid, sodium bromoacetate, 3-chloropropionic acid, 3-bromopropionic acid, α-bromoisobutyric acid or sodium chloroacetate; The mass-to-volume ratio of the haloalkanes carboxylic acid compound to the oil-phase alkane solvent is 0.015:1 to 12:13 g / mL.
7. The preparation method according to claim 1, characterized in that, The vinyl silane compound mentioned in step (5) is selected from one of γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane; The volume ratio of the vinyl silane compound to the oil phase alkane solvent is 0.0074:1 to 0.12:
1.
8. The preparation method according to claim 1, characterized in that, The preparation method of the Fe3O4 magnetic particles includes: Weigh out FeCl3·6H2O and Fe(NH4)2(SO4)2·7H2O and dissolve them in water. Stir and heat to 50-60℃. Add PEG8000 and stir to react. Add ammonia water and heat to continue the reaction. Stop stirring and let stand. Cool to room temperature and perform magnetic separation. Wash to obtain Fe3O4 magnetic particles. The mass ratio of FeCl3·6H2O and Fe(NH4)2(SO4)2·7H2O is 0.27:1 to 0.9:1; The stirring reaction time is 10 min; the temperature is raised to 80℃, the reaction time is 15 min, and the settling time is 1-1.5 h.