CN101572142B - Superparamagnetic core-shell composite nanoparticle and preparation method thereof - Google Patents

Superparamagnetic core-shell composite nanoparticle and preparation method thereof Download PDF

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CN101572142B
CN101572142B CN2009101112018A CN200910111201A CN101572142B CN 101572142 B CN101572142 B CN 101572142B CN 2009101112018 A CN2009101112018 A CN 2009101112018A CN 200910111201 A CN200910111201 A CN 200910111201A CN 101572142 B CN101572142 B CN 101572142B
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composite nanoparticle
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CN101572142A (en
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王周成
梁汉锋
钟和平
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Xiamen University
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Xiamen University
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Abstract

The invention provides a superparamagnetic core-shell composite nanoparticle and relates to magnetic nano materials. The invention provides the superparamagnetic core-shell composite nanoparticle with an inner core being a magnetic MnFe2O4 nanoparticle and a preparation method thereof. The superparamagnetic core-shell composite nanoparticle has a spherical shape and comprises an inner core and a crust; the inner core is the magnetic MnFe2O4 nanoparticle and the crust is a silicon dioxide clad. The preparation method comprises the following steps: dispersing the MnFe2O4 particles in water, stirring the particles, adding tetramethyl ammonium hydroxide solution and carrying out ultrasonic dispersion to form stable suspension; dispersing the suspension in ethanol and stirring the ethanol to obtain solution A; adding ammonia in the solution A and stirring the solution A to obtain solution B; mixing ethyl orthosilicate and absolute ethyl alcohol and adding the solution B to the mixture, separating the product after aging the mixture, washing, filtering and drying the product, thus obtaining the superparamagnetic core-shell composite nanoparticle.

Description

A kind of superparamagnetic core-shell composite nanoparticle and preparation method thereof
Technical field
The present invention relates to a kind of magnetic Nano material, particularly relate to a kind of superparamagnetic core-shell composite nanoparticle and preparation method thereof.
Background technology
Magnetic Nano material is as a kind of important nano material, except that Jie who has nano material at physics, aspect chemical sees (promptly between macroscopic view and microcosmic molecule, atom) characteristic, also have its special magnetic ability-Jie and see magnetic, show as the small-size effect of quantum size effect, superparamagnetism, macro quanta tunnel effect, magnetic order particle, special apparent magnetism etc., it is had a wide range of applications in fields such as information technology, biomedicines.For example, magnetic resonance imaging, the Magnetic Isolation of oligonucleotides, cell and other biological component, and (1.Z.Li, L.Wei, M.Y.Gao, H.Lei, Adv.Mater.2005,17,1001 such as specific site drug delivery system of magnetic force guiding; 2.A.K.Gupta, M.Gupta, Biomaterials 2005,26, and 3995).Pure magnetic nano-particle itself is because certain limitation is subjected to a lot of restrictions in actual applications, for example (3. horse radiance, Su Zhiguo, Wang Ping. nanometer biotechnology: notion, application and prospect. Beijing: Chemical Industry Press, 2008):
1. have high-specific surface area and high-ratio surface energy, and the anisotropic dipole moment effect of particle, tend to form big aggregate;
2. because unstable, recurring structure changes easily, and this can cause the change of magnetic performance and when directly being exposed to biological systems, biodegradation fast can take place.
For fear of these limitation, be necessary magnetic nano-particle is carried out finishing, introduce a suitable rete.Can reduce its surface energy by finishing, improve the oxidation resistance of particle, obtain the nano-complex particle of good dispersion magnetic nano-particle; Suitable finishing simultaneously can be regulated the compatibility and the response characteristic of magnetic nano-particle and other materials.Because SiO 2Performance with following excellence: the dipolar interaction between can the shielding magnetic particle stops particle aggregation; Has excellent biological compatibility, hydrophily and extraordinary stability; And SiO 2The technology of preparing of microballoon is quite ripe, for preparing high-quality SiO 2The magnetic microsphere of modifying provides technical support, and for magnetic Nano microsphere carry out modify and it in bio-medical applications provide main guarantee again by surface biological for simultaneously full-fledged chemistry of silicones.Therefore the preparation of nucleocapsid structure silicon dioxide/magnetic nano-particle and application in recent years becomes a research focus.
The preparation method of nucleocapsid structure silicon dioxide/magnetic nano-particle mainly contains colloidal sol～gel method, reverse microemulsion process, aerosol high-temperature decomposition etc. at present, and wherein colloidal sol～gel method can be divided into the sodium metasilicate Hydrolyze method again, the teos hydrolysis method reaches Method (4.Y.Lu, Y.Yin, B.T.Mayers, Y.Xia, Nano Lett.2002,2,183; 5.W.StPber, A.Fink, E.J.Bohn, J.Colloid Interface Sci.1968,26,62), though these methods respectively have quality, the uneven phenomenon of ubiquity coating in various degree.And, make it can in pure medium, form stable dispersion by to by the modification of coated particle, again at its surperficial coated silica, be expected to obtain to coat uniform core-shell type complex particle.The magnetic kernel of studying more core-shell silica/magnetic nano-composite particle now mostly is Fe 3O 4, CoFe 2O 4Deng, and obtained extensive use.And when being applied to field such as pharmaceutical carrier when it, magnetic responsiveness is by force the prerequisite that realizes its function such as medicine magnetic steering etc., at a series of ferrite magnetic nano material MFe 2O 4In (M=Fe, Mn, Co, Ni etc.), that the magnetic response performance is the most superior is MnFe 2O 4Magnetic nanoparticle, however kernel is MnFe 2O 4Hud typed composite nano materials but do not appear in the newspapers so far.Therefore, preparation is with magnetic MnFe 2O 4Particle is a kernel, and silicon dioxide is the core-shell composite nanoparticle of shell, and great practical application meaning is arranged undoubtedly.
Summary of the invention
It is magnetic MnFe that purpose of the present invention aims to provide a kind of kernel 2O 4Superparamagnetic core-shell composite nanoparticle of nano particle and preparation method thereof.
Superparamagnetic core-shell composite nanoparticle of the present invention is spherical, comprises kernel and shell, and kernel is magnetic MnFe 2O 4Nano particle, shell are the coated with silica layer.
The average grain diameter of described superparamagnetic core-shell composite nanoparticle is 5～50nm.
Technical scheme of the present invention is to magnetic kernel MnFe 2O 4Nano particle carries out surface treatment and the silicon shell coats, and described surface treatment is to adopt Tetramethylammonium hydroxide to MnFe 2O 4Nano particle disperses, and sonicated; It is with the MnFe after the surface treatment that described silicon shell coats 2O 4Nano particle is distributed in the mixed liquor of water and alcohol, is adding under the condition of ammoniacal liquor, is undertaken by teos hydrolysis and condensation reaction.
The preparation method of superparamagnetic core-shell composite nanoparticle of the present invention may further comprise the steps:
1) with MnFe 2O 4Dispersion of Particles stirs in water, adds tetramethyl ammonium hydroxide solution, and ultrasonic dispersion forms steady suspension;
2) above-mentioned suspension is scattered in the ethanol, stirs, get solution A;
3) in solution A, add ammoniacal liquor, stir, get solution B;
4) tetraethoxysilane is mixed with absolute ethyl alcohol, add the solution B reaction, after the ageing, isolate product, washing is filtered, and drying gets superparamagnetic core-shell composite nanoparticle.
Press mass ratio, MnFe 2O 4Particle: water is preferably (1.0～3.0): 50, and MnFe 2O 4The average grain diameter of particle is preferably 5～50nm, and by volume, water: tetramethyl ammonium hydroxide solution is preferably 1: (0.1～0.2), press mass ratio, the concentration of tetramethyl ammonium hydroxide solution is preferably 25%, and the time of ultrasonic dispersion is preferably 30～60min.
By volume, suspension: ethanol is preferably (0.5～1.0): 50, and percentage by volume, concentration of ethanol is preferably 90%～95%.
By volume, suspension: ammoniacal liquor is preferably 1: (4～16), by mass percentage, the concentration of ammoniacal liquor is preferably 25%.
By volume, tetraethoxysilane: absolute ethyl alcohol is preferably 1: (25～200), the time of ageing is preferably 10～30h.
Preparation method's reaction condition gentleness of the present invention, technology is simple, and the particle that makes has following characteristics:
1) composite nanoparticle is a spherical nucleocapsid, and the magnetic kernel number is more, the saturation magnetization height, and at room temperature have superparamagnetism.
2) the composite nanoparticle surface chemistry consists of silicon dioxide, is easy to by silylating reagent its surface be modified, and by modifying the surface that can obtain having functional groups such as amino, sulfydryl, epoxy, helps further application.
The superparamagnetic core-shell composite nanoparticle of the present invention's preparation can be widely used in fields such as information technology, biomedicine, as magnetic resonance imaging, pharmaceutical carrier, targeted drug, bio-separation and sealing and magnetic recording material etc.
Description of drawings
The sample that Fig. 1 prepares under the process conditions of embodiment 2 for the present invention coats the X-ray diffraction spectrogram before and after the silicon shell.In Fig. 1, abscissa be the angle of diffraction 2 θ (°), ordinate is diffraction maximum relative intensity Intensity (a.u.); Curve a is MnFe 2O 4, the crystal face of main diffraction maximum correspondence is followed successively by 111,220,311,400,422,511,440; Curve b is MnFe 2O 4-SiO 2, the crystal face of main diffraction maximum correspondence is followed successively by 111,220,311,400,422,511,440.
The sample that Fig. 2 prepares under the process conditions of embodiment 2 for the present invention coats the fourier infrared conversion spectrogram before and after the silicon shell.In Fig. 2, abscissa is wave number Wavenumber/cm -1, ordinate is absorbance Transmittance (%); Curve a is MnFe 2O 4-SiO 2, curve b is MnFe 2O 4Coat the back sample at～1102cm ～1Near a high strength peak (O-Si-O) is arranged.
Fig. 3 is the magnetic hysteresis loop figure of the present invention after the sample for preparing under the process conditions of embodiment 2 coats the silicon shell.In Fig. 3, abscissa is externally-applied magnetic field intensity H (Oe), and ordinate is the saturation magnetization amount M (emu/g) of particle, and probe temperature is 20K; As seen from Figure 3, there is hysteresis in compound particle under 20K.
Fig. 4 is the magnetic hysteresis loop figure of the present invention after the sample for preparing under the process conditions of embodiment 2 coats the silicon shell.In Fig. 4, abscissa is externally-applied magnetic field intensity H (Oe), and ordinate is the saturation magnetization amount M (emu/g) of particle, and probe temperature is 300K; As seen from Figure 4, under 300K, its remanent magnetism and coercive force are 0, present good superparamagnetism.
The linear fit figure that the The data extrapolation that Fig. 5 records under 20K behind the sample coating silicon shell for preparing under the process conditions of embodiment 2 for the present invention obtains.In Fig. 5, abscissa is externally-applied magnetic field intensity 1/H (Oe reciprocal -1), ordinate is the saturation magnetization amount M (emu/g) of particle; As seen from Figure 5, by can calculate the The data extrapolation that records under the 20K under this temperature the saturation magnetization amount of particle be 33.8emu/g; ● SiO 2@MnFe 2O 4
The transmission electron microscope shape appearance figure of the sample that Fig. 6 prepares under the process conditions of embodiment 3 for the present invention.In Fig. 6, scale is 500nm, and upper right corner enlarged drawing scale is 200nm.
Embodiment
Embodiment 1
(1), takes by weighing the MnFe that the 1.0g average grain diameter is 30nm 2O 4Dispersion of Particles is in the 50g deionized water, and under agitation Dropwise 5 ml 25wt% tetramethyl ammonium hydroxide solution carries out ultrasonic dispersion 30min then, makes it to form steady suspension.
(2), get the above-mentioned suspension of 0.5ml and be scattered in 5ml water and the 50ml absolute ethyl alcohol mixed solution, and it is transferred in the there-necked flask, stir 10min.
(3), add the ammoniacal liquor of 5ml 25wt% in the there-necked flask, stir it mixed.
(4), 0.25ml tetraethoxysilane and 50ml absolute ethyl alcohol are mixed, and place dropping funel, dropwise join in the there-necked flask, course of reaction is followed stirring.
(5), dropwise back room temperature ageing 20h, reaction is carried out fully.
(6), isolate product, washing and filtering, drying can obtain magnetic Nano MnFe 2O 4～SiO 2Compound particle.
Embodiment 2
(1), takes by weighing the MnFe that the 1.5g average grain diameter is 30nm 2O 4Dispersion of Particles is in the 50g deionized water, and under agitation Dropwise 5 ml 25wt% tetramethyl ammonium hydroxide solution carries out ultrasonic dispersion 30min then, makes it to form steady suspension.
(2), get the above-mentioned suspension of 1.0ml and be scattered in 4ml water and the 50ml absolute ethyl alcohol mixed solution, and it is transferred in the there-necked flask, stir 10min.
(3), add the ammoniacal liquor of 6ml 25wt% in the there-necked flask, stir it mixed.
(4), 0.5ml tetraethoxysilane and 50ml absolute ethyl alcohol are mixed, and place dropping funel, dropwise join in the there-necked flask, course of reaction is followed stirring.
(5), dropwise back room temperature ageing 24h, reaction is carried out fully.
(6), with embodiment 1.
Fig. 1 under the process conditions of present embodiment, prepare sample coat X-ray diffractogram before and after the silicon shell.As seen from the figure, the spectrogram that sample coats before and after the silicon shell is about the same, and this has illustrated that the silicon shell that coats is to exist with amorphous state.
Fig. 2 coats the fourier infrared conversion spectrogram of silicon shell front and back for the sample for preparing under the process conditions of present embodiment.The difference of two figure maximums is to coat the back sample at～1102cm ～1Near a high strength peak is arranged, this is SiO 2Due to the antisymmetric stretching vibration of oxygen, this has illustrated that there is SiO really in the sample after coating in the symmetrical stretching vibration of the Si～O in the tetrahedron～Si key and this key 2, i.e. SiO 2Cover MnFe 2O 4Formed a kind of composite nanoparticle on the particle surface.
Fig. 3～5 are magnetic hysteresis loop and the linear fit figure thereof of the present invention after the sample for preparing under the process conditions of present embodiment coats the silicon shell.There is hysteresis in compound particle under 20K as seen from the figure, and under 300K, its remanent magnetism and coercive force are 0, present good superparamagnetism.The saturation magnetization that can extrapolate particle under this temperature by extrapolation is 22.8emu/g.
Embodiment 3
(1), takes by weighing the MnFe that the 1.5g average grain diameter is 30nm 2O 4Dispersion of Particles is in the 50g deionized water, and under agitation Dropwise 5 ml 25wt% tetramethyl ammonium hydroxide solution carries out ultrasonic dispersion 30min then, makes it to form steady suspension.
(2), get the above-mentioned suspension of 1.0ml and be scattered in 4ml water and the 50ml absolute ethyl alcohol mixed solution, and it is transferred in the there-necked flask, stir 10min.
(3), add the ammoniacal liquor of 6ml 25wt% in the there-necked flask, stir it mixed.
(4), 2ml tetraethoxysilane and 50ml absolute ethyl alcohol are mixed, and place dropping funel, dropwise join in the there-necked flask, course of reaction is followed stirring.
(5), (6), with embodiment 1.
Fig. 6 is the transmission electron microscope shape appearance figure of the compound particle for preparing under the process conditions of present embodiment.Zhi Bei product is the composite nanoparticle of spherical nucleocapsid as seen from the figure, and its particle diameter is about 250～300nm, and wherein black is magnetic nano-particle cluster kernel, and what color was more shallow is coating layer silicon dioxide.
Embodiment 4
(1), takes by weighing the MnFe that the 3.0g average grain diameter is 30nm 2O 4Dispersion of Particles under agitation drips 10ml 25wt% tetramethyl ammonium hydroxide solution in the 50g deionized water, carry out ultrasonic dispersion 60min then, makes it to form steady suspension.
(2), get the above-mentioned suspension of 1.0ml and be scattered in 5ml water and the 50ml absolute ethyl alcohol mixed solution, and it is transferred in the there-necked flask, stir 10min.
(3), add the ammoniacal liquor of 8ml 25wt% in the there-necked flask, stir it mixed.
(4), 1.0ml tetraethoxysilane and 50ml absolute ethyl alcohol are mixed, and place dropping funel, dropwise join in the there-necked flask, course of reaction is followed stirring.
(5), (6), with embodiment 1.

Claims (3)

1. the preparation method of a superparamagnetic core-shell composite nanoparticle is characterized in that, described superparamagnetic core-shell composite nanoparticle is spherical, comprises kernel and shell, and kernel is magnetic MnFe 2O 4Nano particle, shell are the coated with silica layer; Described preparation method may further comprise the steps:
1) with MnFe 2O 4Dispersion of Particles stirs in water, adds tetramethyl ammonium hydroxide solution, and ultrasonic dispersion forms steady suspension, presses mass ratio, MnFe 2O 4Particle: water is 1.0～3.0: 50, and by volume, water: tetramethyl ammonium hydroxide solution is 1: 0.1～0.2, presses mass ratio, and the concentration of tetramethyl ammonium hydroxide solution is 25%;
2) above-mentioned suspension is scattered in the ethanol, stirs, solution A, by volume, suspension: ethanol is 0.5～1.0: 50, percentage by volume, concentration of ethanol is 90%～95%;
3) add ammoniacal liquor in solution A, stir, get solution B, by volume, suspension: ammoniacal liquor is 1: 4～16; By mass percentage, the concentration of ammoniacal liquor is 25%;
4) tetraethoxysilane is mixed with absolute ethyl alcohol, add the solution B reaction, after the ageing, isolate product, washing is filtered, and drying gets superparamagnetic core-shell composite nanoparticle, and by volume, tetraethoxysilane: absolute ethyl alcohol is 1: 25～200.
2. a kind of preparation method of superparamagnetic core-shell composite nanoparticle according to claim 1 is characterized in that MnFe 2O 4The average grain diameter of particle is 5～50nm.
3. a kind of preparation method of superparamagnetic core-shell composite nanoparticle according to claim 1, the time that it is characterized in that ultrasonic dispersion is 30～60min.
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