Method for preparing silicon dioxide-coated magnetic microspheres

Abstract

The invention discloses a method for preparing silicon dioxide-coated magnetic microspheres, which belongs to the technical field of nano-magnetic materials. In the method, the characteristic that nanoparticles are easily arranged on a two-phase solution interface is utilized to form oil-in-water emulsion or microemulsion which is stabilized by oil-soluble magnetic nanoparticles and the hydrolysis of tetraethyl orthosilicate is further produced on the surfaces of droplets, so that a silicon dioxide-coated layer is formed. The method has the advantages of no need of using any surfactant, simple reaction operation process and short reaction time; particle diameters of the coated magnetic microspheres are 50 to 400nm; and the magnetic content of the microspheres can be simply controlled at the same time when the particle diameters of the magnetic microspheres are controlled.

Description

technical field

[0001] The invention relates to a method in the technical field of nanometer magnetic materials, in particular to a method for preparing magnetic microspheres coated with silicon dioxide. Background technique

[0002] Superparamagnetic nanoparticles have been widely used in cell separation, hyperthermia, targeted drug delivery, and nuclear magnetic resonance detection due to their characteristics of no remanence and zero coercive force. In the existing preparation methods, the oil-soluble magnetic nanoparticles prepared by the reaction in the oil phase system are significantly better than those prepared by the reaction in the water phase system in terms of morphology, particle size uniformity and crystallinity. water-soluble magnetic nanoparticles. However, for further practical application in the field of biomedicine, it is usually necessary to first convert oil-soluble magnetic nanoparticles into water-soluble ones, and then modify specific functional grou...

Examples

Embodiment 1

[0029] 1. Take 0.811g of ferric chloride and 4.5625g of sodium oleate, disperse them in a mixed solution containing 35mL of n-hexane, 15mL of deionized water and 20mL of absolute ethanol, and stir at 70°C for 4h. Wash with deionized water three times, separate and collect the oil-soluble solution in the upper layer, and dry in an oven for 24 hours to obtain iron oleate, which is set aside.

[0030] 2. Take 5mmol iron oleate and 3.24mL oleic acid, disperse in 30mL 1-octadecene solution, in N 2 Under a protective atmosphere, the temperature was raised to 320° C., and the reaction was carried out for 30 minutes. That is, the oil-soluble ferroferric oxide magnetic nanoparticles are obtained. After the reaction is completed, the reaction product is cooled to room temperature, precipitated with absolute ethanol, and centrifuged several times, and finally dispersed in n-hexane to obtain an oil-soluble magnetic particle dispersion. The concentration of ferric iron tetroxide magnetic...

Embodiment 2

[0034] 1. Take 0.811g of ferric chloride and 4.5625g of sodium oleate, disperse them in a mixed solution containing 35mL of n-hexane, 15mL of deionized water and 20mL of absolute ethanol, and stir at 70°C for 4h. Wash with deionized water three times, separate and collect the oil-soluble solution in the upper layer, and dry in an oven for 24 hours to obtain iron oleate, which is set aside.

[0035] 2. Take 5mmol iron oleate and 3.24mL oleic acid, disperse in 30mL 1-octadecene solution, raise the temperature to 320°C under N2 protective atmosphere, and react for 30min. That is, the oil-soluble ferroferric oxide magnetic nanoparticles are obtained. After the reaction is completed, the reaction product is cooled to room temperature, precipitated with absolute ethanol, and centrifuged several times, and finally dispersed in n-hexane to obtain an oil-soluble magnetic particle dispersion. The concentration of ferric iron tetroxide magnetic nanoparticles is 15 mg / mL.

[0036] 3. Ta...

Embodiment 3

[0039] 1. Take 0.811g of ferric chloride and 4.5625g of sodium oleate, disperse them in a mixed solution containing 35mL of n-hexane, 15mL of deionized water and 20mL of absolute ethanol, and stir at 70°C for 4h. Wash with deionized water three times, separate and collect the oil-soluble solution in the upper layer, and dry in an oven for 24 hours to obtain iron oleate, which is set aside.

[0040] 2. Take 5mmol iron oleate and 3.24mL oleic acid, disperse in 30mL 1-octadecene solution, in N 2 Under a protective atmosphere, the temperature was raised to 320° C., and the reaction was carried out for 30 minutes. That is, the oil-soluble ferroferric oxide magnetic nanoparticles are obtained. After the reaction is completed, the reaction product is cooled to room temperature, precipitated with absolute ethanol, and centrifuged several times, and finally dispersed in n-hexane to obtain an oil-soluble magnetic particle dispersion. The concentration of ferric iron tetroxide magnetic...

technical field

[0001] The invention relates to a method in the technical field of nanometer magnetic materials, in particular to a method for preparing magnetic microspheres coated with silicon dioxide. Background technique

[0002] Superparamagnetic nanoparticles have been widely used in cell separation, hyperthermia, targeted drug delivery, and nuclear magnetic resonance detection due to their characteristics of no remanence and zero coercive force. In the existing preparation methods, the oil-soluble magnetic nanoparticles prepared by the reaction in the oil phase system are significantly better than those prepared by the reaction in the water phase system in terms of morphology, particle size uniformity and crystallinity. water-soluble magnetic nanoparticles. However, for further practical application in the field of biomedicine, it is usually necessary to first convert oil-soluble magnetic nanoparticles into water-soluble ones, and then modify specific functional grou...

Examples

Embodiment 1

[0029] 1. Take 0.811g of ferric chloride and 4.5625g of sodium oleate, disperse them in a mixed solution containing 35mL of n-hexane, 15mL of deionized water and 20mL of absolute ethanol, and stir at 70°C for 4h. Wash with deionized water three times, separate and collect the oil-soluble solution in the upper layer, and dry in an oven for 24 hours to obtain iron oleate, which is set aside.

[0030] 2. Take 5mmol iron oleate and 3.24mL oleic acid, disperse in 30mL 1-octadecene solution, in N 2 Under a protective atmosphere, the temperature was raised to 320° C., and the reaction was carried out for 30 minutes. That is, the oil-soluble ferroferric oxide magnetic nanoparticles are obtained. After the reaction is completed, the reaction product is cooled to room temperature, precipitated with absolute ethanol, and centrifuged several times, and finally dispersed in n-hexane to obtain an oil-soluble magnetic particle dispersion. The concentration of ferric iron tetroxide magnetic...

Embodiment 2

[0034] 1. Take 0.811g of ferric chloride and 4.5625g of sodium oleate, disperse them in a mixed solution containing 35mL of n-hexane, 15mL of deionized water and 20mL of absolute ethanol, and stir at 70°C for 4h. Wash with deionized water three times, separate and collect the oil-soluble solution in the upper layer, and dry in an oven for 24 hours to obtain iron oleate, which is set aside.

[0035] 2. Take 5mmol iron oleate and 3.24mL oleic acid, disperse in 30mL 1-octadecene solution, raise the temperature to 320°C under N2 protective atmosphere, and react for 30min. That is, the oil-soluble ferroferric oxide magnetic nanoparticles are obtained. After the reaction is completed, the reaction product is cooled to room temperature, precipitated with absolute ethanol, and centrifuged several times, and finally dispersed in n-hexane to obtain an oil-soluble magnetic particle dispersion. The concentration of ferric iron tetroxide magnetic nanoparticles is 15 mg / mL.

[0036] 3. Ta...

Embodiment 3

[0039] 1. Take 0.811g of ferric chloride and 4.5625g of sodium oleate, disperse them in a mixed solution containing 35mL of n-hexane, 15mL of deionized water and 20mL of absolute ethanol, and stir at 70°C for 4h. Wash with deionized water three times, separate and collect the oil-soluble solution in the upper layer, and dry in an oven for 24 hours to obtain iron oleate, which is set aside.

[0040] 2. Take 5mmol iron oleate and 3.24mL oleic acid, disperse in 30mL 1-octadecene solution, in N 2 Under a protective atmosphere, the temperature was raised to 320° C., and the reaction was carried out for 30 minutes. That is, the oil-soluble ferroferric oxide magnetic nanoparticles are obtained. After the reaction is completed, the reaction product is cooled to room temperature, precipitated with absolute ethanol, and centrifuged several times, and finally dispersed in n-hexane to obtain an oil-soluble magnetic particle dispersion. The concentration of ferric iron tetroxide magnetic...

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