CN103923656B - A kind of preparation method of gadolinium oxide coated ferroferric oxide magnetic fluorescence nano hollow ball - Google Patents

Abstract

A preparation method of gadolinium oxide-wrapped ferroferric oxide magnetic fluorescent nano hollow spheres, which utilizes a hard template method, uses silicon dioxide with different inner diameters as a template, precipitates iron hydroxide on a gel of silicon dioxide and uses it as a template. The template is further coated with the rare earth element gadolinium, thereby obtaining Gd ₂ O ₃ coated Fe ₃ O ₄ magnetic fluorescent hollow nanospheres with different particle diameters. The invention has the advantages of simple process, low cost and good repeatability, is suitable for large-scale production, and avoids the influence caused by the agglomeration of magnetic particles. The prepared hollow sphere has a relatively large specific surface area; the adjustable range of particle size is relatively large, which broadens the size adjustable field of the hollow sphere; it has magnetic and fluorescent properties at the same time, and its orientation can be controlled by adding a magnetic field and can be transparentized. The high-performance drug carrier can intuitively understand the direction of the drug, and is easy to break under the action of external force or disturbance, and can be used for contrast agents and biomarkers, magnetic resonance imaging (MRI), biological and biomedical imaging.

Description

A preparation method of gadolinium oxide-wrapped ferric iron tetroxide magnetic fluorescent nano hollow spheres

technical field

The invention belongs to the technical field of inorganic nanometer materials, and in particular relates to a preparation method of Gd ₂ O ₃ wrapped Fe ₃ O ₄ magnetic fluorescent nano hollow spheres.

Background technique

In recent years, with the development of technology, it has been found that, compared with bulk materials, the corresponding hollow spheres of the same material have high specific surface area, better penetration and low density, which are useful in catalysis, encapsulation, cell separation, There are very important applications in chemical reactors, drug delivery, lightweight materials, optoelectronic devices, etc. (b) F. Caruso, Top. Curr. Chem. 2003, 227, 145.]. Therefore, the study of hollow microspheres with different compositions has attracted widespread attention, especially the multifunctional hollow microspheres with optical and magnetic properties, which can be localized in a specific area with an external magnetic field for drug delivery and fluorescence imaging. Because of these properties, they have been successfully used as contrast agents and biomarkers for magnetic resonance imaging (MRI), biological and biomedical imaging. Among many optical materials, rare earth materials are favored due to their high photoluminescence (PL) quantum yield, tunable emission wavelength, low phonon energy, and high chemical and thermal stability. Many researchers have prepared such hollow microspheres with crystalline or amorphous nanostructure walls by designing different routes. In the reported articles, the preparation of hollow microspheres is mainly through the template method, that is, using ɑ-Fe ₂ O ₃ , Fe ₃ O ₄ and β-FeOOH particles as templates, through uniform precipitation method, layer-by-layer electrostatic self-assembly method, Sol-gel method, etc., coat inorganic substances on the template, and then remove the template by pyrolysis or dissolution, so as to obtain the corresponding core-shell structure. The template method is further divided into a hard template method and a soft template method. Because the soft template is a series of supramolecular aggregates formed by amphiphilic molecules, when the system environment changes, its morphology may change, which is not conducive to the preparation of monodisperse and regular structures. The hard template method can realize the control of the size and uniformity of the hollow sphere by controlling the size of the hard template, and at the same time do not change its morphology during the reaction system and precipitation process, so that the thickness and composition of the sphere wall can be controlled. Therefore, at present, the preparation of hollow microspheres mostly utilizes the hard template technology, but the preparation method _of magnetically fluorescent hollow _nanospheres wrapped with Gd ₂ O ₃ has not been reported yet.

Contents of the invention

The technical problem to be solved by the present invention is to provide a preparation method of gadolinium oxide-wrapped ferric iron tetroxide magnetic fluorescent nano hollow spheres with simple process, safe operation and low cost, which solves the problem of particle aggregation caused by magnetic particles as templates, In order to achieve the purpose of simplifying the experimental difficulties.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is: a preparation method of gadolinium oxide-wrapped ferroferric oxide magnetic fluorescent hollow nanospheres, which is characterized in that it includes the following steps:

1) Take 1.2-1.6g of silica nanoparticles and add 10-25ml of distilled water to prepare a colloidal silica solution; take 0.200-0.268g of ferric nitrate nonahydrate and 0.200-0.300g of urea and dissolve them in 20-25ml of distilled water, Prepare A mixed solution;

2) Mix the silica colloidal solution prepared above with A mixed solution to prepare B mixed solution, add 40-80ml of distilled water, and stir at 80-95°C for 4-6 hours to obtain a reddish-brown uniform system. After cooling, reddish-brown particle precipitation is obtained, and the first coating outside the particle is completed;

3) After washing and drying the above-mentioned reddish-brown particle precipitate, take 1.0-1.5g and add 10-25ml of distilled water to obtain a uniform colloidal solution; take 0.200-0.310g of gadolinium nitrate hexahydrate and 0.200-0.300g of urea and dissolve them in 20-25ml In distilled water, the C mixed solution was obtained;

4) Mix the homogeneous colloidal solution prepared in step 3) with the mixed solution C to prepare the mixed solution D, add 40-80ml of distilled water, and stir for 4-6 hours at a temperature of 80-95°C to obtain a red uniform system, cool, Red granule precipitation is obtained, and the second coating outside the granule is completed;

5) Take the above-mentioned coated red particles for core etching, and take the red particles at the bottom to precipitate;

6) The dry powder obtained after washing and drying the red particle precipitate at the bottom is reduced with hydrogen to obtain the desired prepared Gd ₂ O ₃ wrapped Fe ₃ O ₄ magnetic fluorescent hollow nanospheres.

The mass or volume of each of the above substances is calculated on the basis of 1.2-1.6 g of silica nanoparticles.

As an improvement, the washing and drying in the step 3) is to wash the precipitated reddish-brown particles with distilled water to obtain reddish-brown particles, and then vacuum-dry at a drying temperature of 30-60°C to obtain dry powder.

As an improvement, the inner core etching in the step 5) is to add 0.5-2.0 mol/L NaOH solution to the red particles for soaking to perform inner core etching, and the soaking time is 3-6 hours.

Further improvement, the washing and drying in the step 6) is to wash the precipitated red particles with distilled water to obtain red particles, and then vacuum-dry them at a drying temperature of 30-60°C to obtain dry powder.

Finally, the process of hydrogen reduction in step 6) is as follows: the flow rate of hydrogen is 40-60mL/min, the heating temperature is controlled at 450-550°C, and the constant temperature and hydrogen flow rate are maintained for 2-3 hours.

Compared with the prior art, the present invention has the advantages of: using a wet injection process to prepare iron/silicon dioxide: and using iron/silicon dioxide as a template to coat Gd ₂ O ₃ and reduce it to obtain metal Fe ₃ O ₄ Gd ₂ O ₃ multifunctional nano-hollow spheres; compared with outsourcing SiO ₂ on magnetic particles and using this as a template for frequency-increasing experiments, the preparation method of the present invention has simple process, safe operation, low cost and good repeatability. It is suitable for large-scale production; the prepared hollow spheres have good dispersion and uniform coating; the surface has a porous structure, a relatively large specific surface area and strong magnetism, which is easy to control and has high application potential in medicine. For contrast agents and biomarkers, nuclear magnetic resonance imaging (MRI), biological and biomedical imaging; and by using templates of different sizes, a large number of Fe ₃ O ₄ Gd ₂ O ₃ multifunctional nano-hollows with different inner diameters can be synthesized as required ball.

Description of drawings

Fig. 1 is the scanning electron micrograph of iron nano hollow sphere in embodiment 1;

Fig. 2 is the scanning electron micrograph of iron-gadolinium composite nano hollow sphere in embodiment 1;

Fig. 3 is the elemental analysis photograph of iron-gadolinium composite nano hollow sphere in embodiment 1;

Fig. 4 is the scanning electron micrograph of iron-gadolinium composite nano hollow sphere in embodiment 2;

Figure 5 is the X-ray diffraction pattern of Fe ₃ O ₄ Gd ₂ O ₃ nano hollow spheres in Example 1 (Fe ₃ O ₄ : JCPDS Card No. 89-6466);

6 is a hysteresis loop diagram of Fe ₃ O ₄ Gd ₂ O ₃ hollow nanospheres in Example 1.

Detailed ways

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

Example 1

① Take 1.5g of nano-microspheres with a particle size of 500nm of silica, add 10ml of distilled water, and sonicate to a uniform colloidal solution.

②Weigh 0.268g of ferric nitrate hexahydrate and 0.290g of urea respectively, mix them together, dissolve them in 20ml of distilled water, and add them into a three-necked flask.

③Put the mixed solution of ① into the three-neck flask of ②, and add 70ml of distilled water to form a red homogeneous colloidal solution.

④Put the three-necked flask into a constant temperature water tank, stir, adjust the temperature of the constant temperature water bath at 95°C, and keep stirring for 4 hours after the system temperature reaches 95°C.

⑤ Centrifuge the above mixed solution, wash with double distilled water, and then centrifuge to obtain a reddish-brown solid precipitate.

⑥ The above steps are a complete process for one-time coating of particles, and the coating of rare earth element gadolinium can be continued on the basis of this product according to the preparation needs. Take 1.5 g of the above prepared nano-microspheres, add 10 ml of distilled water, and sonicate to obtain a uniform colloidal solution.

⑦Weigh 0.310g of gadolinium nitrate hexahydrate and 0.290g of urea respectively, mix them together, dissolve them in 20ml of distilled water, and add them to a three-neck flask. Put the three-necked flask into a constant temperature water tank, stir, adjust the temperature of the constant temperature water bath at 95°C, and keep stirring for 4 hours after the system temperature reaches 95°C.

⑧ Centrifuge the above mixed solution, wash with double distilled water, and then centrifuge to obtain a red solid precipitate.

⑨Add 0.8mol/L NaOH solution to the red solid powder and soak for 4 hours, then pour out the upper layer solution to obtain a red solid precipitate at the bottom. The red solid precipitate was washed several times with distilled water, and the washed powder was vacuum-dried at 60°C in a vacuum oven.

⑩ Take a small amount of the above dry powder, put it in a small quartz boat, and put it into a quartz glass tube. Inject pure hydrogen at 60mL/min, maintain a constant hydrogen flow rate, and use a temperature program to raise the temperature to 450°C within 45 minutes. After maintaining this constant temperature and hydrogen flow rate for 2 hours, stop heating, and let the furnace and quartz tube naturally cool to room temperature. During this period, a constant hydrogen flow was maintained for 12 hours. At this time, the quartz tube can be opened, the quartz boat can be carefully taken out, and the powder can be quickly put into a small reagent bottle for vacuum storage.

As shown in Figure 2, it can be seen from the SEM (Scanning Electron Microscopy) figure that the Fe ₃ O ₄ Gd ₂ O ₃ hollow nanospheres in this example have a spherical and hollow structure, good dispersion, and a particle size of Uniform, with strip-like protrusions on the surface, the thickness of the coated shell is about 50nm, and there are small holes on the surface.

Example 2

The proportioning in the method of above-mentioned embodiment 1 is constant, uses silicon dioxide particle diameter 180nm as inner core, carries out coating, then etches away inner core with sodium hydroxide 0.5mol/L, reduces with hydrogen, and reduction temperature remains at 450° C., other conditions were the same as in Example 1, and Fe ₃ O ₄ Gd ₂ O ₃ hollow nanospheres were obtained. It can be seen from the SEM of Figure 4 that the overall coating is relatively uniform, monodisperse and regular.

In conclusion, the present invention reports a method of using a hard template method, using silica with different inner diameters as a template, and synthesizing metal Fe ₃ O ₄ Gd ₂ O ₃ hollow nanospheres with inner diameters of about 500nm and 180nm through a hydrolysis process. We used the wet injection process and reduced it to obtain metallic Fe ₃ O ₄ Gd ₂ O ₃ hollow nanospheres.

The hollow spheres obtained in this patent have a relatively large specific surface area; the adjustment range of the particle size is relatively large, which broadens the size adjustable field of the hollow spheres; the Fe ₃ O ₄ Gd ₂ O ₃ nano hollow spheres have fluorescence and magnetism, Its orientation can be controlled by adding a magnetic field, and the drug carrier with transparent optical properties can intuitively understand the direction of the drug, and this porous hollow sphere is easy to break under the action of external force or disturbance, which has great potential as a drug carrier in medicine in the future. High potential application value. At present, such materials with fluorescent and magnetic properties have been successfully used in contrast agents and biomarkers, magnetic resonance imaging (MRI), biological and biomedical imaging.

Claims (4)

1. a preparation method for gadolinium oxide coated ferroferric oxide magnetic fluorescence nano hollow ball, is characterized in that comprising the steps:

1) get nano SiO 2 particle 1.2 ~ 1.6g, add 10 ~ 25ml distilled water, obtained silica colloid solution; Getting nine water ferric nitrate 0.200 ~ 0.268g and urea 0.200 ~ 0.300g is dissolved in 20 ~ 25ml distilled water, obtained A mixed liquor;

2) by above-mentioned obtained silica colloid solution and the mixing of A mixed liquor, obtained B mixed liquor, adds 40 ~ 80ml distilled water, stir 4 ~ 6 hours under 80 ~ 95 DEG C of temperature conditions, obtain bronzing homogeneous system, cooling, obtain red-brownish coloured particles precipitation, complete particle outer coated for the first time;

3) by after above-mentioned red-brownish coloured particles precipitation cleaning-drying, get 1.0 ~ 1.5g, add 10 ~ 25ml distilled water, obtained homogeneous colloids solution; Getting six water gadolinium nitrate 0.200 ~ 0.310g and urea 0.200 ~ 0.300g is dissolved in 20 ~ 25ml distilled water, obtained C mixed liquor;

4) by step 3) the homogeneous colloids solution prepared and the mixing of C mixed liquor, obtained D mixed liquor, adds 40 ~ 80ml distilled water, stir 4 ~ 6 hours under 80 ~ 95 DEG C of temperature conditions, obtain red homogeneous system, cooling, obtain red granules precipitation, complete the outer second time of particle coated;

5) get above-mentioned coated after red granules carry out core etching, get bottom red granules precipitation; Described core etching in red granules, adds the immersion of 0.5 ~ 2.0mol/L NaOH solution carry out core etching, and soak time is 3 ~ 6 hours;

6) the dried powder hydrogen reducing obtained after the red granules of bottom precipitation cleaning-drying can be obtained the Gd of required preparation ₂o ₃parcel Fe ₃o ₄magnetic fluorescence nano hollow ball;

Above the quality of each material or volume with nano SiO 2 particle 1.2 ~ 1.6g for benchmark.

2. preparation method according to claim 1, is characterized in that described step 3) in cleaning-drying be with distilled water cleaning red-brownish coloured particles precipitation obtain red-brownish coloured particles, then vacuumize, baking temperature remains on 30 ~ 60 DEG C, obtains dried powder.

3. preparation method according to claim 1, is characterized in that described step 6) in cleaning-drying be with distilled water cleaning red granules precipitation obtain red granules, then vacuumize, baking temperature remains on 30 ~ 60 DEG C, obtains dried powder.

4. preparation method according to claim 1, it is characterized in that described step 6) in the technique of hydrogen reducing be: the air velocity of hydrogen is 40 ~ 60mL/min, heating and temperature control, at 450 ~ 550 DEG C, keeps this steady temperature and hydrogen flow rate 2 ~ 3 hours.