CN114288267A - Noble metal nanoparticles/silica nano-space capsule composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a precious metal nano-particle/silicon dioxide nano-space capsule composite material and a preparation method thereof; the preparation method comprises the following steps: Step 1, dispersing the precious metal nano-particles in water, adding silver nitrate and reacting with a reducing agent to obtain Precious metal/silver core-shell nanoparticle dispersion; step 2, drop the dispersion into a mixed solvent of water/alcohol, add two ligands, surfactant and ammonia water under vigorous stirring, and the two ligands are mercapto groups respectively Carboxylic acid ligand and polyacrylic acid with large molecular weight; step 3, continue to add silicon source and stir to obtain a hollow nanocomposite material in the shape of a space capsule. The preparation method of the invention is simple, the conditions are mild, and the shape is controllable, and the asymmetric sac-like nanostructure with openings on the surface is obtained.

Description

Noble metal nanoparticle/silica nano capsule composite material and preparation method thereof

technical field

The invention belongs to the technical field of nanomaterials, and in particular relates to a metal core-shell nanoparticle/silicon dioxide capsule-shaped hollow nanocomposite material and a preparation method thereof.

Background technique

It is well known that asymmetric structures based on plasmonic nanoparticles inherit the unique optical and physical properties of noble metals (such as localized surface plasmon resonance and photothermal effects), but also endow them with new properties, such as high geometric asymmetry, which makes them ideal for Many important fields are of great interest, such as interfacial stabilizers as molecular surfactant analogs, sensing, delivery vehicles, imaging, nanoreactors, self-driven nanorobots, and cells for assembling complex structures. However, to date, most of the reported structures are solid materials that do not provide sufficient storage space for functional guest molecule loading, greatly limiting their expansion and further practical applications. Therefore, the rational design and construction of asymmetric saccular nanostructures with openings on the surface is a great challenge.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the purpose of the present invention is to provide a noble metal nanoparticle/silica nano-capsule composite material and a preparation method thereof. The preparation method of the invention is simple, the conditions are mild, and the shape is controllable, and the asymmetric sac-like nanostructure with openings on the surface is obtained.

The technical solutions of the present invention are specifically introduced as follows.

The invention provides a preparation method of a precious metal nanoparticle/silica nanometer space capsule composite material.

The material has a space capsule structure as a whole, which is an asymmetric sac-like nanostructure with an opening on the surface, consisting of a sea urchin-like spine-shaped head and an open hollow tail connected to the head, wherein the head is a core-shell structure, The inner core is a precious metal nanoparticle, the outer shell is a silver shell, and the hollow tail is made of nano-silica; it is prepared by the following method:

Step 1: Disperse the precious metal nanoparticles in water, add a reducing agent and silver nitrate to stir the reaction, centrifuge the concentration after the reaction, and then further disperse into water to obtain precious metal/silver core-shell nanoparticles with a concentration between 0.5-100 μg/mL Dispersions;

Step 2: After adding the precious metal/silver core-shell nanoparticle dispersion dropwise to the alcohol aqueous solution, add ligand aqueous solution, surfactant aqueous solution and ammonia water under stirring condition, and continue to stir for 20-40min after adding; Composed of mercaptocarboxylic acid and polyacrylic acid;

In step 3, a silicon source is added to the solution obtained in step 2, and a stirring reaction is performed to obtain a capsule-shaped hollow nanocomposite material.

Preferably, in step 1, the precious metal nanoparticles are gold nanoparticles, and the reducing agent is selected from any one of hydroquinone, sodium citrate or sodium borohydride; the concentration of the precious metal/silver core-shell nanoparticle dispersion is 20- between 60 μg/mL.

Preferably, in step 2, the alcohol is any one of methanol, ethanol, isopropanol or butanediol; the volume ratio of water and alcohol is 1:1-1:10; the precious metal/silver core-shell nanoparticle dispersion liquid The volume ratio between the aqueous solution of alcohol and alcohol is 1:1-1:10.

Preferably, in step 2, in the ligand, the mercaptocarboxylic acid is mercaptopropionic acid, 4-mercaptobenzoic acid or 4-methylphenylthioethyl

Acid, the weight average molecular weight MW of polyacrylic acid is between 1000-10000; the concentration of mercaptocarboxylic acid aqueous solution is 1-50 mmol/L, the concentration of polyacrylic acid aqueous solution is 1-50 mmol/L, the volume of mercaptocarboxylic acid aqueous solution and polyacrylic acid aqueous solution The ratio is 1:1-10:1; the volume ratio of the noble metal/silver core-shell nanoparticle dispersion liquid and the ligand aqueous solution is 1:5-20:1; the stirring speed is 100-1000rpm.

Preferably, in step 2, the surfactant is sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, polyvinylpyridine

Any one of rolidone, cetyltrimethylammonium bromide CTAB or cetyltrimethylammonium chloride CTAC; the concentration of the surfactant aqueous solution is 0.0001-2 g/ml.

Preferably, in step 3, the silicon source is selected from the group consisting of tetraethoxysilane, tetramethoxysilane or ethyl orthosilicate

The stirring speed is 100-500 rpm, and the stirring time is 5-15 h.

Preferably, the volume ratio of the aqueous surfactant solution, the silicon source, and the ammonia water is 600:1:90-600:10:90.

The present invention also provides a precious metal nanoparticle/silicon dioxide nano-space capsule composite material prepared by the above-mentioned preparation method. The composite material has a space capsule structure as a whole, which is an asymmetric sac-shaped nano-structure with openings on the surface. It consists of a sea urchin-like spine-shaped head and an open hollow tail connected to the head. The head is a core-shell structure, the inner core is a precious metal nanoparticle, the outer shell is a silver shell, and the hollow tail is made of nano-silica.

Preferably, the length of the head of the composite material is between 40-130 nm, and the opening size of the open hollow tail is between

Between 70-240 nm.

The present invention further provides an application of the above-mentioned composite material in nano-drug carriers.

Compared with the prior art, the beneficial effects of the present invention are:

1. The present invention provides a precious metal nanoparticle/silicon dioxide nano-capsule composite material, which is a composite structure in which a core-shell structure is connected with a nano-silica space capsule, the core of the core-shell structure is gold nanoparticles, and the outer shell is composed of It is composed of silver shell, and the opening diameter of the cabin can be controlled by controlling the amount of ligand.

2. The components in the composite material of the present invention have excellent biocompatibility and biosafety, and the core-shell structure has strong near-infrared absorption peaks and photothermal effects, which are suitable for photothermal therapy of cancer, and have The open cabin structure has high specific surface area, low density and high drug loading, so the composite material of the present invention has a good application prospect as a nano drug carrier.

Description of drawings

FIG. 1 is a transmission electron microscope (TEM) image of the gold-silver core-shell structure prepared in Example 1 of the present invention.

FIG. 2 is the XRD diffraction pattern of the gold-silver core-shell structure prepared in Example 1 of the present invention.

FIG. 3 is a transmission electron microscope (TEM) image of the noble metal nanoparticles/silicon dioxide nano-capsule composite material prepared in Example 1 of the present invention.

FIG. 4 is a scanning electron microscope (SEM) image of the noble metal nanoparticles/silicon dioxide nano capsule composite material prepared in the embodiment of the present invention.

Fig. 5 is the ultraviolet-visible absorption spectrum diagram of noble metal nanoparticles/silicon dioxide nano space capsule prepared by the present invention.

FIG. 6 is a transmission electron microscope image of noble metal nanoparticles/silicon dioxide nano capsules with different hollow diameters prepared by the present invention.

Detailed ways

In order to make it easy to understand the technical means, creative features, achieved goals and effects of the present invention, the present invention is described in detail below with reference to the embodiments and the accompanying drawings.

Example 1

The noble metal nanoparticle/silica nanocapsule nanocomposite was prepared by the following methods:

Step 1, add 2.0ml of gold nanoparticle suspension with a particle size of about 30-90nm at a concentration of 5μg/ml into a vial, then add 120μl of hydroquinone at a concentration of 10mM, and 120μl of nitric acid at a concentration of 10mM Silver, after stirring and reacting for 2 hours, centrifuged and concentrated to further disperse in 400 μl of water to obtain a gold-silver core-shell nanoparticle dispersion;

Step 2, drop the nanoparticle dispersion of gold-silver core-shell structure into 3 ml of a mixed solution of isopropanol and water with a volume ratio of 4:1, and then add 25 μl under stirring at a speed of 700 rpm. 5mM 4-methylphenylthioacetic acid solution and 25μl of 5mM polyacrylic acid solution as co-ligands, then 600μl of 0.0015g/mL cetyltrimethylammonium bromide surfactant solution and 90μl of 25wt% Ammonia, stir for 30 minutes.

Step 3 To the solution of Step 2, add 1 μl of TEOS, a silicon source, and stir at 300 rpm for 12 hours to obtain a precious metal nanoparticle/silicon dioxide nanocapsule composite material.

The morphology of the noble metal nanoparticle/silica nanocapsule composite material in this example, as shown in Figures 1 and 2, is the particle size distribution reference of the obtained gold and silver nanoparticles, and the phase analysis confirms that the core Synthesis of Shell Structures. Figures 3 and 4 are the transmission and scanning electron microscope images of the prepared composites, respectively, confirming that the morphology of the structure consists of a noble metal head and a hollow tail connected; the diameter of the head is about 100 nm, and the head is a core-shell Structure, the size of the opening of the hollow tail is about 150 nm, and the hollow tail is composed of silica. Figure 5 is the UV-Vis absorption spectrum measured by UV-Vis spectrophotometer, and the results confirm that the coating of silica does not affect the UV-absorbing results of precious metals.

Example 2:

The noble metal nanoparticle/silica nanocapsule composite material is prepared by the following method, and the method includes the following steps:

Step 1, add 2.0ml of gold nanoparticle suspension with a particle size of about 30-90nm at a concentration of 5μg/ml into a vial, then add 120μl of hydroquinone at a concentration of 10mM, and 120μl of nitric acid at a concentration of 10mM Silver, after stirring and reacting for 2 hours, centrifuged and concentrated to further disperse in 400 μl of water to obtain a gold-silver core-shell nanoparticle dispersion;

Step 2, drop the gold-silver core-shell structure nanoparticle dispersion into 3 ml of a mixed solution of isopropanol and water with a volume ratio of 4:1, and then add 25 μl under stirring at a speed of 700 rpm. 5 mM 4-mercaptobenzoic acid in water, and 25 μl polyacrylic acid in water at a concentration of 1-50 mM mM as co-ligands, then 600 μl cetyltrimethylammonium bromide surfactant solution and 90 μl 25wt% ammonia , stir for 30 minutes.

Step 3: Add 1 μl of silicon source TEOS to the solution obtained in Step 2, and stir at 300 rpm for 12 hours to obtain a precious metal nanoparticle/silicon dioxide nanocapsule composite material.

Figure 6 shows the transmission electron microscope images of different products obtained by adding 1-50 mM polyacrylic acid in water. The results show that the opening size of the silica compartment can be precisely adjusted by controlling the amount of the ligand polyacrylic acid aqueous solution added. Specifically, when the ligand concentration is 1 mM, the opening size of the hollow tail is about 80 nm; The ligand concentration is 5 mM; the opening size of the hollow tail is about 120 nm; when the ligand concentration is 10 mM, the opening size of the hollow tail is about 150 nm; when the ligand concentration is 15 mM, the opening size of the hollow tail is about 180 nm nm; when the ligand concentration was 20 mM, the size of the opening of the hollow tail was about 210 nm; finally, a series of capsule structures with different openings were synthesized.

The above embodiments are preferred cases of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (10)

1. a preparation method of noble metal nanoparticle/silicon dioxide nano space capsule composite material, is characterized in that, this composite The material has a space capsule structure as a whole, which is an asymmetric sac-like nanostructure with an opening on the surface, consisting of a sea urchin-like spine-shaped head and an open hollow tail connected to the head, wherein the head is a core-shell structure, The inner core is a precious metal nanoparticle, the outer shell is a silver shell, and the hollow tail is made of nano-silica; it is prepared by the following method: Step 1: Disperse the precious metal nanoparticles in water, add a reducing agent and silver nitrate to stir the reaction, centrifuge the concentration after the reaction, and then further disperse into water to obtain precious metal/silver core-shell nanoparticles with a concentration between 0.5-100 μg/mL Dispersions; Step 2: After adding the precious metal/silver core-shell nanoparticle dispersion dropwise to the alcohol aqueous solution, add ligand aqueous solution, surfactant aqueous solution and ammonia water under stirring condition, and continue to stir for 20-40min after adding; Composed of mercaptocarboxylic acid and polyacrylic acid; In step 3, a silicon source is added to the solution obtained in step 2, and a stirring reaction is performed to obtain a capsule-shaped hollow nanocomposite material. 2. preparation method according to claim 1, is characterized in that, in step 1, precious metal nano-particles are gold nano-particles For particles, the reducing agent is selected from any one of hydroquinone, sodium citrate or sodium borohydride; the concentration of the noble metal/silver core-shell nanoparticle dispersion liquid is between 20-60 μg/mL. 3. preparation method according to claim 1 is characterized in that, in step 2, alcohol is methanol, ethanol, isopropanol or any one of butanediol, the volume ratio of water and alcohol is 1:1-1:10; the volume ratio between the noble metal/silver core-shell nanoparticle dispersion liquid and the aqueous solution of alcohol is 1:1-1: 10. 4. preparation method according to claim 1, is characterized in that, in step 2, in the ligand, mercaptocarboxylic acid is mercapto Propionic acid, 4-mercaptobenzoic acid or 4-methylphenylthioacetic acid, the weight-average molecular weight MW of polyacrylic acid is between 1000-10000; the concentration of mercaptocarboxylic acid aqueous solution is 1-50 mmol/L, and the concentration of polyacrylic acid aqueous solution is 1-50 mmol/L, the volume ratio of mercaptocarboxylic acid aqueous solution and polyacrylic acid aqueous solution is 1:1-10:1; the volume ratio of noble metal/silver core-shell nanoparticle dispersion and ligand aqueous solution is 1:5-20: 1; The stirring speed is 100-1000 rpm. 5. preparation method according to claim 1, is characterized in that, in step 2, surfactant is dodecyl sulfide Any one of sodium, sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, cetyltrimethylammonium bromide CTAB or cetyltrimethylammonium chloride CTAC; concentration of surfactant in aqueous solution 0.0005-2 g/ml. 6. preparation method according to claim 1 is characterized in that, in step 3, silicon source is selected from silicon source and is tetraethoxy Silane, tetramethoxysilane or ethyl orthosilicate, the stirring speed is 100-500 rpm, and the stirring time is 5-15h. 7. preparation method according to claim is characterized in that, the volume of surfactant aqueous solution, silicon source, ammoniacal liquor The ratio is 600:1:90-600:10:90. 8. a kind of noble metal nanoparticle/silicon dioxide nano space made according to the preparation method described in one of claims 1-7 Cabin composite material, characterized in that, the composite material has a space capsule structure as a whole, which is an asymmetric sac-like nanostructure with an opening on the surface, and consists of a sea urchin-like spine-shaped head and an open hollow tail connected to the head. The head is a core-shell structure, the inner core is a noble metal nanoparticle, the outer shell is a silver shell, and the hollow tail is a nano-silica material. 9. The composite material according to claim 8, wherein the length of the head is between 40-130 nm, and the size of the opening of the open hollow tail is between 70-240 nm. 10. An application of the composite material according to claim in nano-drug carrier.

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