CN107790075B - A kind of preparation method of magnetic mesoporous SiO2 nanoparticles of core-shell-shell structure - Google Patents

Abstract

The invention discloses a preparation method of magnetic mesoporous SiO ₂ nanoparticles with a core-shell-shell structure. The method uses Fe ₃ O ₄ as a magnetic carrier, ethyl orthosilicate as a silicon source, Methyl ammonium chloride was used as surfactant to obtain Fe ₃ O ₄ @SiO ₂ @mSiO ₂ magnetic mesoporous nanoparticles with a core-shell-shell three-layer structure of radial mesoporous morphology, while using N-[3-(trimethyl) Oxysilyl)propyl]ethylenediamine is an aminosilane coupling agent that supports amino groups on its surface and pores. In addition, the present invention also uses triethylamine and cyclohexane as organic swelling agents to obtain a mesoporous layer with larger pore size. The magnetic mesoporous SiO ₂ nanoparticles prepared by the method of the invention have good magnetic properties, high dispersibility and unique pore structure, and have wide application prospects in drug release, biology, materials science and the like.

Description

A kind of preparation method of magnetic mesoporous SiO2 nanoparticles of core-shell-shell structure

technical field

The invention belongs to the field of preparation of mesoporous materials, and in particular relates to a preparation method of magnetic mesoporous SiO ₂ nanoparticles with a core-shell-shell structure.

Background technique

Mesoporous _SiO2 nanoparticles are nanomaterials with radial vertical channels on the surface. Due to the larger specific surface area and unique pore structure of mesoporous SiO ₂ microspheres, it is widely used in composite materials, biology, medicine and other fields, especially in adsorption applications and drug release. Magnetic mesoporous SiO ₂ nanoparticles are magnetic particles embedded in mesoporous SiO ₂ to form a core-shell two-layer structure, which makes them magnetic while maintaining a unique pore structure. The core-shell-shell three-layer structure has a larger particle size and a more complete spherical structure, and more molecules can be loaded on its surface and pores.

The magnetic mesoporous SiO ₂ nanoparticles prepared by the existing methods cannot see a complete and uniform pore structure, and there are many deficiencies in terms of morphology and application (Document 1: Wang Miaomiao, et al. Mesoporous SiO ₂ Immobilization of Laccase by Fe ₃ O ₄ Hollow Magnetic Microspheres[J]. Journal of Chemistry of Higher Education Institutions, 2013(2): 299～305. Literature 2: WeiweiZhao.et.al Novel Method To Investigate the Interaction Force between Etoposide and APTES-Functionalized Fe ₃ O ₄ @nSiO ₂ @mSiO ₂ Nanocarrier for DrugLoading and Release Processes. Phys. Chem. C 2015, 119, 4379～4386). Therefore, it is necessary to develop a preparation method of magnetic mesoporous nanoparticles with good dispersion, complete structural layering, clear and uniform pore structure, so as to further meet the needs of practical applications.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of magnetic mesoporous SiO ₂ nanoparticles with core-shell-shell structure, which is simple, the prepared magnetic mesoporous SiO ₂ nanoparticles have uniform particle size distribution, and the pore structure is clearly visible, The adsorption capacity and drug loading were significantly improved.

To achieve the above object, the technical solution of the present invention is:

A preparation method of magnetic mesoporous SiO nanoparticles with core _- shell-shell structure, comprising the following steps:

Step 1: Disperse the Fe ₃ O ₄ magnetic nanoparticles in a mixed solution of ethanol and water, using tetraethyl orthosilicate (TEOS) as the silicon source and ammonia water (NH ₃ ·H ₂ O) as the alkali source, at 30-40 React at ℃ to obtain Fe ₃ O ₄ @SiO ₂ magnetic nanoparticles with core-shell structure;

Step 2, according to the mole ratio of Fe ₃ O ₄ @SiO ₂ , H ₂ O, ammonia water, CTAC and EDPS to be 1.4～2.1:125～130:1:0.2～0.3:0.15～0.2, the ethanol solution of TEOS and water, The volume ratio of ethanol is 1:11: ₅ , the _Fe3O4 @ _SiO2 in step 1 is dispersed in a mixed solution of ethanol, water and cetyltrimethylammonium chloride (CTAC), and _NH3 is added ·H ₂ O was used as alkali source and catalyst. Under stirring conditions, the ethanol solution of TEOS with a concentration of 1.2-1.4 M was added dropwise to the reaction system. After the particles were formed, the aminosilane reagent N-[3-(trimethoxy) was added. (silyl)propyl]ethylenediamine (EDPS), after stirring overnight, the product was magnetically separated, and the product was refluxed in acetone to remove the surfactant CTAC to obtain a three-layered Fe ₃ O ₄ @SiO ₂ @mSiO ₂ - EDPS magnetic nanoparticles, namely magnetic mesoporous _SiO2 nanoparticles with core-shell-shell structure.

In step 1, the molar ratio of Fe ₃ O ₄ , ammonia water and TEOS is 0.35-0.45:57-86:9.6-19.2, and the volume ratio of ethanol and water is 4:1.

In step 2, the acetone reflux time is 10-14h, and the acetone reflux is repeated 1-2 times.

Further preferred scheme, in step 2, before adding EDPS, add triethylamine (TEA) with a volume of 10% of ammonia water, while TEOS is changed to be dissolved in equimolar amount of cyclohexane, so that a medium with a larger pore size can be obtained. Pore layer.

Compared with the prior art, the present invention has the following remarkable effects: the Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS magnetic mesoporous SiO ₂ nanoparticles prepared by the present invention have uniform particle size distribution, good dispersibility, and a three-layer core. The shell structure is obvious, the pore structure is clearly visible, the colloid is stable, it is not easy to aggregate in solution, and the surface is loaded with a large number of amino groups; as the core of the particle, the Fe ₃ O ₄ magnetic nanoparticles have good magnetic response properties, and under the action of an external magnetic field The rapid separation and controlled migration of magnetic mesoporous nanoparticles can be achieved under low pressure. At the same time, the unique pore structure, large specific surface area and pore volume can significantly improve the adsorption capacity and drug loading capacity, and the adsorption capacity for DNA can reach 218.43 mg/g. .

Description of drawings

1 is a transmission electron microscope image of Fe ₃ O ₄ @SiO ₂ (a) and Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS (b) magnetic mesoporous nanoparticles prepared in Example 1. FIG.

FIG. 2 is a graph of N ₂ adsorption and desorption curves and a pore size distribution graph of the magnetic mesoporous nanoparticles prepared in Example 1. FIG.

FIG. 3 is a hysteresis loop diagram of the magnetic mesoporous nanoparticles prepared in Example 1. FIG.

FIG. 4 is a transmission electron microscope image of the large-aperture magnetic mesoporous nanoparticles prepared in Example 2. FIG.

5 is a transmission electron microscope image of the magnetic mesoporous nanoparticles prepared in Comparative Examples 1-3.

FIG. 6 is a UV spectrum of Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS prepared in Example 3 for separating DNA.

Detailed ways

The present invention will be described in further detail below in conjunction with the embodiments and the accompanying drawings.

Example 1: Preparation of Magnetic Mesoporous Nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS

Disperse 100 mg of Fe ₃ O ₄ magnetic nanoparticles in a mixture of 160 mL of ethanol and 40 mL of water under ultrasonication for 40 min, add 2 mL of NH ₃ ·H ₂ O under vigorous mechanical stirring, and then add 2.5 mL of TEOS dropwise within 10 min at 35°C. Stirring was continued for 6 h, washed with ethanol and deionized water for three times, magnetically separated, and vacuum dried at 40 °C for 10 h to obtain Fe ₃ O ₄ @SiO ₂ magnetic microspheres with uniform size and core-shell structure coated with SiO ₂ .

Take 80 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres and disperse them in a mixed solution containing 95 mL of water, 43 mL of ethanol, 2.5 mL of ammonia water and 0.3 g of CTAC by ultrasound for 30 min. Subsequently, 2.5 mL of TEOS was mixed in 6 mL of ethanol and added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and 2.5 mL of EDPS was added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the product was re-dispersed in 60 mL of acetone, and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C to obtain a complete structure and uniform particle size. , Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS with radial channels.

The TEM image of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is shown in Fig. 1(a), it can be seen that Fe ₃ O ₄ @SiO ₂ microspheres have a particle size of about 325nm, regular structure, uniform particle size and dispersibility High, especially Fe ₃ O ₄ @SiO ₂ microspheres have a complete core-shell structure and the shell thickness is around 60 nm. The prepared magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS showed an obvious core-shell-shell three-layer structure, as shown in Fig. 1(b), the middle layer was a solid SiO ₂ layer, The outermost layer is SiO ₂ with radial pore structure, and the particle size of the whole nanoparticles is about 415 nm.

The N adsorption and desorption curves of magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS are shown in Fig. _2. It can be seen from Fig. ₂ that the N adsorption and desorption curves of magnetic mesoporous nanoparticles belong to IV , which is consistent with the characteristic curve of the mesoporous structure. At the same time, the BET specific surface area of the mesoporous nanoparticles was 217.8 m ² /g, and the pore volume was 0.161 m ³ /g. The pore size distribution diagram showed that the pore size was concentrated at 3.3 nm.

The magnetic response intensity of the magnetic mesoporous nanoparticle Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS is shown in Fig. 3. It can be seen from Fig. 3 that the saturation magnetic moment of the magnetic mesoporous SiO ₂ nanoparticle is 8.73 emu/g, Compared with the bare Fe ₃ O ₄ , it is much smaller, but the effect of the external magnetic field can be fully utilized in the separation process, and the separation and enrichment can be achieved within 30s.

Example 2: Preparation of Large-Aperture Magnetic Mesoporous Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS Nanoparticles

The preparation method of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is the same as that of Example 1.

Take 80 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres and disperse them in a mixed solution containing 95 mL of water, 49 mL of ethanol, 2.5 mL of ammonia, 0.18 mL of triethylamine (TEA) and 0.3 g of CTAC by ultrasound for 30 min. Subsequently, 2.5 mL of TEOS was dissolved in 6 mL of cyclohexane and added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and 2.5 mL of EDPS was also added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the nanoparticles were re-dispersed in 60 mL of acetone and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C to obtain large-pore magnetic mesoporous Fe. ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS nanoparticles, the product is shown in TEM as shown in Figure 4.

Figure 4 is the transmission electron microscope image of the large-diameter magnetic mesoporous Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS nanoparticles. It can be seen that when TEOS was dissolved in the organic solvent cyclohexane and added to the reaction system, when TEOS When the hydrolyzed oligomers and CTAC form micelles, due to the swelling effect of cyclohexane, the pores are expanded, which solves the small pore size limited by the CTAC chain length, and further increases the pore size to 9-10 nm.

Comparative Example 1: Preparation of Magnetic Mesoporous Nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS Using NaOH as Alkali Source

The preparation method of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is the same as that of Example 1.

80 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres were taken and dispersed in a mixed solution containing 95 mL of water, 43 mL of ethanol, 0.013 g NaOH and 0.3 g CTAC by ultrasonic for 30 min. Subsequently, 2.5 mL of TEOS was mixed in 6 mL of ethanol and added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and 2.5 mL of EDPS was also added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the nanoparticles were re-dispersed in 60 mL of acetone, and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and dried in vacuum at 40 °C to obtain NaOH as the alkali source. Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS.

The TEM image of the magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS with NaOH as the alkali source is shown in Figure 5a. It can be seen that when NaOH is used instead of ammonia water as the alkali source, the prepared magnetic Pore nanoparticles can not see obvious pore structure, and in the present invention, ammonia water not only acts as an alkali source, but also acts as a catalyst.

Comparative Example 2: Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS prepared by adding TEOS alone

The preparation method of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is the same as that of Example 1.

80 mg of the above Fe ₃ O ₄ @SiO ₂ magnetic microspheres were dispersed in a mixed solution containing 95 mL of water, 49 mL of ethanol, 2.5 mL of ammonia and 0.3 g of CTAC by ultrasonication for 30 min. Subsequently, 2.5 mL of TEOS was added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and 2.5 mL of EDPS was also added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the nanoparticles were re-dispersed in 60 mL of acetone and refluxed at 70 °C for 12 h to remove CTAC. In order to ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C. TEOS was added to the prepared magnetic medium separately. Porous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS.

The TEM image of the magnetic mesoporous nanoparticle Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS prepared by adding TEOS alone is shown in Fig. 5b. It can be seen that in the case of adding TEOS alone, due to the faster hydrolysis rate, more Tends to homogeneous nucleation rather than coating on Fe ₃ O ₄ @SiO ₂ particle surfaces. In the present invention, TEOS is dissolved in ethanol and added, which effectively controls the hydrolysis speed of TEOS, and plays a great role in obtaining three-layer mesoporous magnetic microspheres with complete structure and uniform particle size.

Comparative Example 3: Preparation of Magnetic Mesoporous Nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS

The preparation method of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is the same as that of Example 1.

Take 80 mg of Fe ₃ O ₄ magnetic microspheres and disperse them in a mixed solution containing 95 mL of water, 43 mL of ethanol, 2.5 mL of ammonia water and 0.3 g of CTAC by ultrasonication for 30 min. Subsequently, 2.5 mL of TEOS was mixed in 6 mL of ethanol and added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and an additional 2.5 mL of EDPS was also added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the nanoparticles were re-dispersed in 60 mL of acetone, and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C. The TEM image of the product is shown in 5c .

It can be seen from Figure 5c that when the bare Fe ₃ O ₄ magnetic microspheres are directly coated with mesoporous SiO ₂ , a complete core-shell mesoporous structure is not obtained, and the mesoporous structure is not uniform, so the present invention selects A layer of mesoporous structure is made on the coated solid SiO ₂ layer.

Example 3: Preparation of Magnetic Mesoporous Nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS

Disperse 80 mg of Fe ₃ O ₄ magnetic nanoparticles in a mixture of 160 mL of ethanol and 40 mL of water under ultrasonication for 40 min, add 3 mL of NH ₃ ·H ₂ O under vigorous mechanical stirring, and then add 4 mL of TEOS dropwise within 10 min. Continue stirring for 6 h, wash with ethanol and deionized water three times, magnetically separate, and vacuum dry at 40 °C for 10 h to obtain Fe ₃ O ₄ @SiO ₂ magnetic microspheres with uniform size and core-shell structure coated with SiO ₂ .

Take 80 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres and disperse in a mixed solution containing 95 mL of water, 43 mL of ethanol, 4 mL of ammonia water and 0.3 g of CTAC by ultrasound for 30 min. Subsequently, 2 mL of TEOS was mixed in 7.5 mL of ethanol and added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and 2.5 mL of EDPS was added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the product was re-dispersed in 60 mL of acetone, and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C to obtain a complete structure and uniform particle size. , Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS with radial channels.

Example 4: Preparation of Magnetic Mesoporous Nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS

The preparation method of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is the same as that of Example 1.

Take 80 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres and disperse them in a mixed solution containing 95 mL of water, 43 mL of ethanol, 2.5 mL of ammonia water and 0.4 g of CTAC by ultrasound for 30 min. Subsequently, 2.5 mL of TEOS was mixed in 6 mL of ethanol and added dropwise to the reaction system with stirring. After 15 min of reaction, the particles were formed, and 3.5 mL of EDPS was added dropwise to the system. After 18 h of reaction at room temperature, the product was collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the product was re-dispersed in 60 mL of acetone, and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C to obtain a complete structure and uniform particle size. , Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS with radial channels.

Example 5: Preparation of Magnetic Mesoporous Nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS

The preparation method of Fe ₃ O ₄ @SiO ₂ magnetic microspheres is the same as that of Example 1.

Take 60 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres and disperse them in a mixed solution containing 95 mL of water, 43 mL of ethanol, 2 mL of ammonia water and 0.3 g of CTAC by ultrasonication for 30 min. Subsequently, 4 mL of TEOS was mixed in 6 mL of ethanol and added dropwise to the reaction system with stirring. After 15 minutes of reaction, the particles were formed, and 2 mL of EDPS was added dropwise to the system. After 18 hours of reaction at room temperature, the products were collected by magnetic separation, and washed with ethanol and water for three times respectively. Finally, the product was re-dispersed in 60 mL of acetone, and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once. The product was thoroughly washed with ethanol and vacuum dried at 40 °C to obtain a complete structure and uniform particle size. , Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS with radial channels.

Example 6: Magnetic mesoporous nanoparticles Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS for DNA extraction experiments

Prepare 1mg/mL standard DNA solution (initial absorbance at 260nm is 0.880), take 250μL into a 1.5mL centrifuge tube, in order to obtain the maximum adsorption capacity of the prepared magnetic mesoporous nanoparticles for DNA, different amounts of Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS suspension (100 μL, 150 μL, 200 μL, 250 μL, 300 μL) was added, and then pH 4.0 buffer (10 mM Tris-HCl, 1 mM EDTA) was added to the 1 mL reaction system, and after the adsorption process continued for 20 min, the magnetic The microspheres were separated, the supernatant was diluted and the UV absorbance at 260 nm was measured. The UV spectrum is shown in Figure 6.

It can be seen from Fig. 6 that with the increase of Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS microspheres, the total amount of DNA adsorption also increases gradually, indicating that the prepared Fe ₃ O ₄ @SiO ₂ @mSiO ₂ - EDPS microspheres have strong adsorption capacity for DNA. When the particle suspension used is 300 μL, the adsorption efficiency reaches 90%. At the same time, the maximum adsorption capacity of DNA is calculated to be 218.43 mg/g.

Claims (1)

1. the preparation method of the magnetic mesoporous SiO of a core-shell _- shell structure nano-particle, is characterized in that, comprises the following steps: Step 1: Disperse the Fe ₃ O ₄ magnetic nanoparticles in a mixture of ethanol and water, use TEOS as the silicon source, and NH ₃ ·H ₂ O as the alkali source, and react at 30-40 ° C to obtain a core-shell structure. Fe ₃ O ₄ @SiO ₂ magnetic nanoparticles; Step 2, take 80 mg Fe ₃ O ₄ @SiO ₂ magnetic microspheres and disperse them in a mixed solution containing 95 mL of water, 49 mL of ethanol, 2.5 mL of ammonia, 0.18 mL of triethylamine and 0.3 g of CTAC by ultrasound for 30 min; then, 2.5 mL of TEOS was dissolved in 6 mL of cyclohexane and added dropwise to the reaction system under stirring conditions. After 15 min of reaction, the particles were formed, and 2.5 mL of EDPS was also added dropwise to the system. The product was separated and collected, washed three times with ethanol and water respectively; finally, the nanoparticles were re-dispersed in 60 mL of acetone and refluxed at 70 °C for 12 h to remove CTAC. To ensure complete removal of CTAC, the process was repeated once, and the product was thoroughly washed with ethanol , and vacuum dried at 40 °C to obtain large-diameter magnetic mesoporous Fe ₃ O ₄ @SiO ₂ @mSiO ₂ -EDPS nanoparticles.

Images