KR102350646B1 - Method of gold nanorod transformation in nanoscale confinement of zif-8 - Google Patents

Abstract

The present invention relates to a method of controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, capable of coating the surface of metal nanoparticles with ZIF-8 which is a metal organic frame body having a specific surface area, and enabling branched metal nanoparticles, which are grown in a limited space by transforming the shape of the metal nanoparticles through chemical etching and regrowth reaction, to have a high superficial, electric field amplification and a high light/head effect. In accordance with the present invention, the method of controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8 includes: a first step of manufacturing a gold nanorod by using chloroauric acid (HAuCl4), sodium borohydride (NaBH4), silver nitrate (AgNO3) and ascorbic acid to hexadecyltrimethylammonium bromide (CTAB); a second step of coating the surface of the gold nanorod with zeolitic imidazolate framework-8 (ZIF-8) by making the manufactured gold nanorod react to 2-methylimidazole and a zinc nitrate solution; a third step of etching the coated gold nanorod into a gold nanoball; and a fourth step of reducing the gold nanoball for regrowth.

Description

Method of controlling the shape of gold nanorod particles in nanometer local space of ZIF-8

In the present invention, branched gold nanoparticles grown in a limited space by coating ZIF-8, a metal-organic framework having a high specific surface area, on the surface of gold nanoparticles, and transforming the shape of gold nanoparticles through chemical etching and regrowth reactions. A method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8 prepared to exhibit high surface area, electric field amplification and high photothermal effect.

Hybrid nanomaterials composed of metal nanoparticle cores and porous inorganic shells exhibit unique properties and novel functions in sensing, catalysis and solid-state reactions. The incorporation of a porous inorganic shell into a single metal nanoparticle could allow for the stability of the nanoparticle core, which would otherwise be sensitive and fragile in the solution phase. In addition, if the porosity and polarity of the inorganic shell are controlled, the hybrid nanomaterial can be utilized as a molecular selection sensor. Catalytic nanoparticle cores made of platinum or gold enable enhanced catalytic activity and product selectivity due to the synergistic effect between the core-shell. The intrinsic solid-state reactivity of nanoparticles at high temperatures can also be studied because the porous inorganic shell structure provides a separate space.

Understanding the confinement effect in nanometer space of hybrid nanostructures is very important for understanding and controlling the properties and functions of nanoparticles. At the molecular level, the chemical and physical behavior of constrained molecules can be altered differently than in bulk, often allowing hybrid materials to achieve unprecedented chemical reactivity. _{For example, CO 2} molecules trapped at the interface in the nanocavity between the nanoparticle core and the metalorganic framework may exist in a quasi-condensed state obtained only at high pressure.

Beyond the molecular level phenomenon, porous inorganic shells can be utilized for non-traditional metal nanoparticle growth and morphological transformation by nanoscale entrapment of core-shell nanostructures. Egg yolk-shell nanoreactors have been shown to enable precise size control of nanocrystals in a confined space. As another example, there is a report that several nanometer-sized branches are grown by mesopores of silica shells from gold nanoparticle cores of various shapes. However, unlike commonly used inorganic shells such as silica and zeolites, metalorganic frameworks can provide nanocavities of various physical and chemical properties, although nanoscale confinement effects on the morphological changes of metal nanoparticle cores. did not apply to the investigation. Therefore, the exploration of the nanoscale confinement effect by metal-organic frameworks in hybrid nanostructures will expand the chemical scope of metal nanoparticle shape transformation and contribute to obtaining optimal properties and functions for desired applications.

Korean Patent No. 10-1595819

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a method for controlling the shape of gold nanoparticles capable of controlling a chemical reaction in a limited nanometer space.

The technical problems to be solved by the invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

The method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8 according to the present invention,

A first step of preparing a gold nanorod using hexadecyltrimethylammonium bromide (CTAB) chlorauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid;}

A second method in which the prepared gold nanorods are reacted with 2-methylimidazole and an aqueous solution of zinc nitrate to coat zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods. step;

a third step of etching the coated gold nanorods to form gold nanospheres; and

It is characterized in that it is carried out by; a fourth step of reducing the gold nanospheres and re-growth.

The generation of gold nanorods in the first step is,

Step 1-1 to prepare a seed solution by mixing hexadecyltrimethylammonium bromide (CTAB) with chloroauric acid (HAuCl ₄ ) and sodium borohydride (NaBH _{4 );} and

The chloroauric acid (HAuCl ₄ ), Silver nitrate (AgNO ₃ ), ascorbic acid, and the seed solution are added to hexadecyltrimethylammonium bromide (CTAB) to produce gold nanorods in steps 1-2; characterized in that it is performed by.

The coating of ZIF-8 on the surface of the gold nanorods in the second step is,

Step 2-1 of centrifuging the gold nanorod aqueous solution prepared in the first step (S10) to remove the supernatant, adding deionized water, and then mixing; and

The gold nanorods to which the deionized water was added and Zn(NO ₃ ) ₂ .6H ₂ O were sequentially injected into 2-methylimidazole and stirred to form ZIF-8 (zeolitic) on the surface of the gold nanorods. It is characterized in that it is carried out by the 2-2 step of coating the imidazolate framework-8).

The coated gold nanorods,

It is characterized in that it is located in the inner center of the ZIF-8 (zeolitic imidazolate framework-8).

The etching of the third step is,

Step 3-1 of centrifuging the coated gold nanorod solution, discarding the supernatant, and mixing the solvent with hexadecyltrimethylammonium bromide (CTAB) with stirring; and

After the solvent exchange, _{the 3-2 step of mixing chloroauric acid (HAuCl 4} ) is characterized in that it is carried out.

The regrowth of the fourth step is,

a step 4-1 of centrifuging the gold nanospherical solution, discarding the supernatant, and stirring and mixing hexadecylpyridinium chloride monohydrate (CPC) for solvent exchange; and

After the solvent exchange, _{the 4-2 step of mixing chloroauric acid (HAuCl 4} ) and ascorbic acid; characterized in that it is performed.

In addition, the molecular sensor using gold nanorod particles in the nanometer local space of ZIF-8 of the present invention is,

A first step of preparing a gold nanorod using hexadecyltrimethylammonium bromide (CTAB) chlorauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid;}

The prepared gold nanorods were reacted with an aqueous solution of 2-methylimidazole and zinc nitrate to form zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods prepared in the rod shape. A second step of coating on;

a third step of etching the coated gold nanorods to form gold nanospheres; and

It is characterized in that it is manufactured including; a fourth step of re-growth by reducing the gold nanospheres.

In addition, the drug delivery system using gold nanorod particles in the nanometer local space of ZIF-8 of the present invention is,

A first step of preparing a gold nanorod using hexadecyltrimethylammonium bromide (CTAB) chlorauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid;}

The prepared gold nanorods were reacted with an aqueous solution of 2-methylimidazole and zinc nitrate to form zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods prepared in the rod shape. A second step of coating on;

a third step of etching the coated gold nanorods to form gold nanospheres; and

It is characterized in that it is manufactured including; a fourth step of re-growth by reducing the gold nanospheres.

By means of solving the above problems, the present invention can provide a method for controlling the shape of gold nanoparticles capable of controlling a chemical reaction in a limited nanometer space.

In addition, the present invention can control the shape of the gold nanorod particles inside by using ZIF-8, a porous nanoparticle, as a template, so that it can be used as a molecular sensor and a drug carrier.

In addition, according to the present invention, branched gold nanoparticles grown in a limited space can exhibit high surface area, electric field amplification, and high photothermal effect.

1 is a flowchart illustrating a method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8 according to the present invention.
FIG. 2 is a schematic diagram illustrating changes in the shape of gold nanorods through etching and regrowth after coating gold nanorod particles with ZIF-8.
FIG. 3 is a photograph of a change in the shape of the gold nanorod of FIG. 2 analyzed with a transmission electron microscope.
4 is a schematic diagram showing the shape change of the gold nanorods etched with various concentrations of HAuCl _{4 .}
5 is HAuCl ₄ Gold nanorods (hereafter, Rod@ZIF), hemispheres (hereafter, Semi@ZIF), spheres (hereafter, Sphere@ZIF) and voids in ZIF-8 at concentrations of 0, 66, 125 and 291 μM (top to bottom) (hereinafter, Empty ZIF) is a UV visible spectrum graph.
6 is a graph analyzing the dimensions of the core nanorods under the conditions of Rod@ZIF, Semi@ZIF, Sphere@ZIF, and Empty ZIF. The average width is shown in red, and the average length is shown in blue.
7 is a TEM image of Rod@ZIF, Semi@ZIF, Sphere@ZIF, and Empty ZIF conditions, and element mapping (red for Au, green for Zn) is shown at the bottom together with the corresponding TEM images, respectively.
8 is a photograph showing the color-coded overlay surface contours according to the local surface curvature values of the cores in the TEM images of the conditions of Rod, Rod@ZIF, Semi@ZIF, Sphere@ZIF, and Empty ZIF before coating.
9 is a graph showing the local surface curvature distribution of Rod, Rod@ZIF, Semi@ZIF, and Sphere@ZIF.
Figure 10 is the XRD pattern (bottom to top) of Rod@ZIF, Semi@ZIF, Sphere@ZIF and Empty ZIF, the inset shows the XRD signal magnified from 35° to 48° in 2θ.
11 is isothermal linear plots for _{N 2} adsorption and desorption using Rod@ZIF (left plot) and Sphere@ZIF (right plot).
12 is a schematic diagram of Sphere@ZIF for a reductive regrowth reaction.
13 is a UV visible spectrum (changed from blue curve to red curve) of Sphere@ZIF for the reductive regrowth reaction for 1 to 21 minutes and a solution picture for the reductive regrowth reaction.
14 is a TEM image of Sphere@ZIF after reductive regrowth reaction for 1 min, 4 min and 12 min.
15 is a circuit diagram and TEM image of gold nanospheres after reductive regrowth reaction at 4 min.
16 is a schematic diagram and TEM image of Sphere@S-ZIF after reductive regrowth reaction at 4 min.

Terms used in this specification will be briefly described, and the present invention will be described in detail.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, which may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

In the entire specification, when a part “includes” a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein.

Specific details including the problem to be solved for the present invention, the means for solving the problem, and the effect of the invention are included in the embodiments and drawings to be described below. Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The overall reaction process of the method for controlling the particle shape of gold nanorods in the nanometer local space of ZIF-8 according to the present invention is shown in FIGS. 1 and 2 .

First, in the first step (S10), a gold nanorod is manufactured. The gold nanorods were prepared with a length of 52.9±4.2 nm and a width of 14.2±1.1 nm, and were prepared through a seed growth method.

More specifically, the first step (S10) is the first step 1-1 (S11), based on 1 part by weight of hexadecyltrimethylammonium bromide (hereinafter, CTAB) chloroauric acid (hereinafter, HAuCl ₄ ) 0.0027 weight After mixing the parts, 0.0006 parts by weight of sodium borohydride (hereinafter NaBH ₄ ) were mixed, stirred at room temperature for 1 minute, and then aged at 30° C. for 20 minutes without stirring to prepare a seed solution.

With respect to 1 part by weight of _{HAuCl 4 in} step 1-2 (S12), Silver nitrate (hereinafter AgNO ₃ ) 0.0769 parts by weight, 0.5052 parts by weight of ascorbic acid, and 185 parts by weight of CTAB were added to the seed solution, stirred at 30° C., and aged for 2 hours without stirring to produce gold nano-rods. The resulting gold nanorods were centrifuged twice for 15 minutes to disperse the gold nanorods, and then stored in CTAB.

Next, in the second step (S20), the gold nanorods prepared in the first step (S10) are coated with ZIF-8. As shown in Fig. 2(a), the aqueous solution of the gold nanorods was reacted with an aqueous solution of 2-methylimidazole and zinc nitrate to form ZIF (shell thickness = length 150.2 ± 10.8 nm, width 126.3 ± 14.0 nm).

More specifically, in step 2-1 (S21), the gold nanorod aqueous solution prepared in the first step (S10) is centrifuged for 15 minutes, and a portion of the supernatant is discarded. Deionized water is added to the gold nanorods and then mixed. Then, the gold nanorod solution and 2-methylimidazole were sequentially injected into Zn(NO ₃ ) ₂ .6H ₂ O, stirred for 5 minutes, aged for 3 hours, centrifuged for 15 minutes, and the supernatant was collected After discarding, the product is dispersed in methyl alcohol by vortexing and sonicating for 5 minutes. Centrifuge for 15 minutes and discard the supernatant to disperse the product and store in methyl alcohol.

As the aqueous gold nanorod solution is injected into the mixture of the ZIF precursor, nucleation and growth of the ZIF begins on the surface of the gold nanorod using the CTAB bilayer. This is due to the property that CTAB has adsorption affinity for the 100 crystal fatsets of ZIF-8. Therefore, the CTAB bilayer on the surface of the gold nanorods can induce the nucleation of ZIF-8 and lead to a continuous growth process to form core-shell hybrid particles. In addition, CTAB in solution controls the growth of the shell, allowing for cubic shape and size control. As a result, as the coated gold nanorods are centered inside the multi-domain ZIF shell, a core-shell hybrid (hereinafter Rod@ZIF) is formed.

Next, in the third step (S30), the ZIF-coated gold nanorods (hereinafter, Rod@ZIF) prepared in the second step (S20) are oxidized and etched to generate gold nanospheres (hereinafter, Sphere@ZIF). do. The oxidation etching is performed _{using HAuCl 4} and CTAB.

More specifically, the Rod@ZIF solution prepared in the second step (S20) is centrifuged, the supernatant is discarded, and CTAB is stirred and mixed at 40° C. for 10 minutes to solvent exchange the methyl alcohol with the CTAB. Thereafter, the solvent-exchanged Rod@ZIF is _{mixed with a methyl alcohol solution of HAuCl 4} and mixed at 40° C. for 30 minutes. The resulting pale pink solution is centrifuged for 10 minutes and the supernatant is discarded and stored in methyl alcohol.

As shown in FIG. 3(b) , the gold nanorod core may be oxidized etched into a sphere (hereinafter, Sphere@ZIF), and the ZIF shell maintains its original shape while slightly increasing the shell thickness. In the present invention, it is assumed that the relative shell thickness from Rod@ZIF to Sphere@ZIF may occur due to repositioning of the ZIF shell domain after local structural transformation. The oxidative etching may create an empty space at the interface between the gold nanorod core and the adjacent shell to secure a limited space for further chemical reaction.

As shown in Fig. 5, the ^{proportionalionation between Au +} and Au ³⁺ caused the dissolution of gold atoms in the nanorod tip with the valence adjusted to a rather low level. The etching step was monitored through the UV visible spectrum.

When the ZIF shell is formed, the longitudinal localized surface plasmon resonance (LSPR) band of the gold nanorods is redshifted from 781 nm to 806 nm compared to the case without the ZIF shell. The transverse LSPR band at 513 nm showed a subtle change after the ZIF shell formation. The redshift of the longitudinal LSPR band is due to the change in refractive index surrounding the nanorods due to the ZIF shell. The shape of the LSPR band did not change even after shell formation, reflecting that the core nanoparticles were well dispersed and coated without agglomeration between particles. As shown in FIG. 5 , as the HAuCl ₄ concentration increased during the oxidation etching process, the longitudinal LSPR band shifted blue from 806 nm to 524 nm, and _{when 291 μM of HAuCl 4} was added, the longitudinal LSPR band was almost disappear The inset graph highlights the difference between the accumulated UV-visible spectra for each condition in the wavelength range of 450 to 600 nm. The blue shift in the longitudinal LSPR band of the Rod@ZIF indicates the geometric transformation from anisotropy to isotropy of the nanorod core.

As shown in FIGS. 6 to 7 , quantitative analysis of the core shape of Rod@ZIF through the oxidation etching was performed based on TEM images. As shown in FIG. 6 , as the oxidation etching proceeded, the length of the nanorod core in the longitudinal direction was linearly decreased from 50.7 nm of Rod@ZIF to 32.7 nm of Semi@ZIF and 18.0 nm of Sphere@ZIF. However, the width of the nanorods did not change significantly from 13.9 nm to Rod@ZIF, 14.6 nm to Semi@ZIF, and 13.0 nm to Sphere@ZIF. The length and width of the nanorod core eventually converge to 13 nm at Sphere@ZIF. Under a high concentration of HAuCl ₄ (291 μM), all of the nanorod cores were oxidatively etched, leaving a clearly void space inside the ZIF shell. As shown in Fig. 7, the elemental mapping of the oxidized etched hybrid showed a distinct spatial distribution of Au in the core and Zn in the shell. As the nanorod core becomes more oxidatively etched, the signal for Au decreases, consistent with the geometrical analysis.

As shown in FIGS. 8 to 9 , in the oxidation etching step, in addition to dimensional analysis, quantitative analysis of the core shape was performed. The curvature distribution of the core configuration indicates that the Rod @ ^-1 of from 0㎚ ZIF to 0.15㎚ Sphere @ ^-1 of ZIF showed a gradual movement, than the non-etched core curved morphology more wise. The decrease in the ratio of the low curvature values confirms the preferential longitudinal etching events observed in the aforementioned dimension analysis. In addition, the curvature value converges to ^{0.15nm -1 in Sphere@ZIF, indicating shape isotropy.}

10 to 11, the internal structure and core-etched species of Rod@ZIF were investigated using powder X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) surface analysis. As shown in FIG. 10 , the XRD pattern of the Rod@ZIF was the same as the XRD pattern of the ZIF-8 particles having the corresponding peak. It can be seen that the ZIF shell of Rod@ZIF manufactured in the present invention maintains the original crystallinity. The gold nanorod core of Rod@ZIF was identified by two high intensity peaks at 38° for Au111 and 44.5° for Au200.

In addition, the core-etched species (Semi@ZIF, Sphere@ZIF, and Empty ZIF) maintained the same signal for Rod@ZIF and ZIF-8 with unaltered relative intensities, so that subsequent etching of Rod@ZIF on the core particles was This indicates that the overall crystal structure of the ZIF shell was not affected. The XRD peak assigned to the nanorod core appears to decrease gradually as the etching further occurs because the amount of gold in Rod@ZIF decreases.

On the other hand, the average size of the ZIF shell estimated by the Scherrer equation was found to be 540 Å for Rod@ZIF and 509 Å for Sphere@ZIF with full width at the maximum half of the first XRD peak. It was hypothesized that the slight decrease in average size could occur due to local decomposition of the ZIF shell near the intercrystalline ZIF domain, which could be induced by the acidic environment during the etching reaction with _{HAuCl 4 .}

In addition, as shown in Fig. 11, the microporous properties of Rod@ZIF and Sphere@ZIF were investigated with the amount _{of adsorbed and desorbed N 2 .} Rod @ BET surface area of the ZIF can be written as 1,217㎡ · g ^-1 less than the ^{ZIF-8 (1,892㎡ · g -1} ). This decrease in surface area could be due to the added mass increase in the nanorod core and the potential local non-microporosity arising from the multi-region ZIF junction. 11 , the BET surface area did not change significantly between Rod@ZIF and Sphere@ZIF, _{and isotherm linear plots for N 2} adsorption and desorption were almost identical. Sphere@ZIF does not contain as many gold atoms as Rod@ZIF, so it is expected to have a higher BET surface area than Rod@ZIF, however, etching may result in local structural deformation of the ZIF shell and similar BETs. This speculation about the decrease in the BET surface area of Sphere@ZIF can be supported by the increase of the surface area outside the t-plot against the BET surface area of Sphere@ZIF.

Next, in the fourth step (S40), the gold nanospheres (Sphere@ZIF) generated in the third step (S30) are reduced and re-growth. In the fourth step (S40), the reductive regrowth is performed using HAuCl ₄ and ascorbic acid.

More specifically, the Sphere@ZIF stored in the methyl alcohol is centrifuged for 10 minutes, the supernatant is completely discarded, and the solvent is exchanged with hexadecylpyridinium chloride monohydrate (hereinafter CPC). Ascorbic acid in HAuCl ₄ and the above Sphere@ZIF are sequentially added to the CPC solution while gently shaking.

As shown in FIG. 3( c ), in the present invention, branched gold nanospheres such as raspberry can be grown inside the ZIF.

As shown in Figs. 12 to 16, compared with the demonstration of the present invention for a template that inhibited the etching of the nanorod core in a nanoscale confined space, in the present invention, a Sphere was used to study the chemical modification of the core trapped in the ZIF shell. @ZIF I did a reduction regeneration to seeds.

As shown in FIG. 13 , as HAuCl ₄ and ascorbic acid reacted with the Sphere@ZIF, the UV visible spectrum started to show an LSPR band at 536 nm within 4 minutes of the reaction. The LSPR band continued to grow with a response of 13 min and then decreased, and its shape broadened and extended to near-infrared wavelengths. After 15 min of reaction, the regrown core nanoparticles appeared to undergo aggregation, and it can be confirmed that the solution color changes from pink to lavender.

As shown in FIG. 14 , the TEM image with respect to the reaction time can confirm the morphological deformation of the spherical core in the Sphere@ZIF. It was confirmed that the reductive growth of core nanoparticles trapped in the ZIF shell is template-dependent. Aliquots of the reaction solution were collected at 1 min, 4 min, and 12 min of reaction and dried immediately on a TEM grid to avoid further reaction. The chemical species deposited on the TEM grid remained, and the corresponding TEM image contained hazy areas and it was difficult to suppress the reaction because the reductive regrowth proceeded rapidly. Otherwise, it would be possible to utilize the regrown nanospheres for practical applications advantageous for nanobranched structures, such as surface-enhanced Raman signaling and photothermal therapy.

The core nanoparticles (core diameter = 16.5±3.0 nm) obtained at 1 minute of reaction grew larger than the initial core, and raspberry-shaped branches (spot width = 7.7±2.1 nm) with the core nanoparticles as the outline were formed. After 4 minutes, the core nanoparticles were decorated with distinct branches than those obtained with the 1-minute reaction. As the core nanoparticles grew and branched, the multidomain ZIF shell seemed to crack and disintegrate. The etched void space of the nanorod ^{core was calculated to be 6,474 nm 3} (85% of the nanorod core volume), which appears to be sufficient for nanobranch formation. However, the nanobranches were shown to grow in all three-dimensional directions towards the voids as well as the adjacent ZIF shells. The complex chemical interaction in the presence of ascorbic acid, HAuCl ₄ and hexadecylpyridinium chloride monohydrate (CPC) can cause more structural deformation of the ZIF shell than etching during regeneration. It was found that the sample obtained from the 12-minute reaction contained only polygonal gold nanoparticles without a ZIF shell. As shown in FIG. 15 , a control experiment was conducted using gold nanospheres without ZIF shells, and we observed octahedrons rather than raspberry-shaped vine particles. Therefore, it is presumed that the ZIF shell played an important role in governing the formation of branched nanospheroids. In the present invention, we hypothesize that raspberry-like core regrowth in Sphere@ZIF can be derived from three complex factors: the voids created by etching, the multi-domain properties of the ZIF shell, and the local structural deformation of the ZIF shell during etching and regrowth reactions. do.

In the present invention, as shown in Fig. 16, gold nanospheres coated with a single domain ZIF shell (Sphere@S-ZIF) were obtained and reductive regeneration was performed to support the hypothesis. The ZIF shell of Sphere@S-ZIF was cubic in shape, with one or two spherical cores inside the ZIF shell. Through reductive regrowth of Sphere@S-ZIF, no morphological alterations were found in the core nanoparticles, in contrast to that observed with Sphere@ZIF. There were some core nanoparticles that were deformed in the 10 min reaction, where the ZIF shell appeared to degrade more over the extended reaction time. Because the solution is acidic due to HAuCl ₄ , even in single domain Sphere@S-ZIF, the ZIF shell naturally degrades and the core nanoparticles become vulnerable to the reducing environment. One reason for the branched core formation could come from the voids present in Sphere@ZIF. The nanoscale voids between the core and the adjacent ZIF shell created in the etching of the nanorod core can serve as reservoirs of chemical species and promote branching in the core.

It has been reported that gold nanobranches are formed when ^{Au 3+ and ascorbic acid concentrations are increased.} A recent report showed that nano-sized cavities could help to concentrate chemical species inside porous templates. Also, the multi-domain nature of Sphere@ZIF can cause raspberry-like core regrowth. Multidomain shells may contain mesopores hidden in the intercrystalline ZIF domain. The mesopores are likely to help better transport chemical species to the core nanoparticles, and may also serve as nanoscale pathways through which gold atoms grow.

In addition, in the present invention, it is assumed that the multiple domains of Sphere@ZIF are composed of heterogeneous facets rather than a single 100 crystal facet that dominates in cubic ZIF particles (Sphere@S-ZIF). 100 crystal facets are known to be more resistant and stable in acidic conditions than other crystal facets. Therefore, in the present invention, local structural modification of the ZIF shell _{may have occurred for etching and regrowth reactions in HAuCl 4} and acidic environments, which may also contribute to the branched growth of core nanoparticles.

TEM images of Rod@ZIF and Sphere@ZIF after multiple wash treatments can be examined to reveal porosity and potential local strains between crystallites in multi-domain shells. As the hybrid nanoparticles were washed with methyl alcohol, it was confirmed that the multi-domain ZIF shell was vulnerable to separation between domains, and the interfacial space between the ZIF domains could be extended. As more washings were performed, the separation between the domains of Sphere@ZIF increased, resulting in more internal structural modifications. Our assumptions about cross-conduit supported regrowth can be further supported by reductive regrowth for Rod@ZIF. Branched nanospheres grew at the ends of the rods, which was not observed in the peeled nanorods.

In addition, the present invention can manufacture a molecular sensor using gold nanorod particles in a nanometer local space of ZIF-8. After preparing gold nanorod particles by the method for controlling the shape of gold nanorod particles in the nanometer local space of ZIF-8 described above, the selectivity for targeting specific molecules is limited to a size that can pass through the pores of ZIF-8. can

Since the inside of the gold nanorod particle has a local surface plasmon resonance phenomenon, the Raman signal enhancement can be expected for molecules adsorbed on the gold nanoparticle surface, thereby maximizing the probe performance.

For example, nitrobenzenethiol molecules that are smaller than the pores of ZIF-8 can be detected by Raman analysis after penetrating the pores and adsorbing them to the surface of gold nanoparticles. However, Rhodamine 6G molecules that are larger than the pores of ZIF-8 cannot penetrate into the pores and thus cannot be detected by Raman analysis.

Therefore, when various kinds of substances are dissolved in the solution and the substance to be detected is smaller than the pores of ZIF-8, Raman analysis using a molecular sensor using gold nanorod particles in the nanometer local space of ZIF-8 according to the present invention It can be predicted that separation and detection are possible through

In addition, the present invention can prepare a drug delivery system using gold nanorod particles in a nanometer local space of ZIF-8. The advantage of producing gold nanorod particles by the method for controlling the shape of gold nanorod particles in the nanometer local space of ZIF-8 described above, and loading various drugs into one particle and delivering it to a desired site and ZIF- 8 The stability of drug delivery by the shell can be expected.

For example, a drug can be functionalized on the surface of gold nanoparticles, and since it is non-toxic, the drug can be delivered to target cells in the human body without toxicity. In the case of ZIF-8, the drug can be injected and delivered into the pores, and when the site of a specific pH condition is reached, the drug can be released inside by dissociation of ZIF-8. Based on these properties, the drug delivery system using gold nanorod particles in the nanometer local space of ZIF-8 of the present invention can load various drugs.

In addition, it is expected that the ZIF-8 shell will serve to protect the loaded drug, improving the stability of drug delivery, unlike the existing drug delivery system composed of only nanoparticles.

Experimental examples carried out in the present invention are described below.

Experimental example) Materials and methods

1. Material

Sodium borohydride (99%, NaBH ₄ , Sigma-Aldrich), gold (III) chloride trihydrate (99.9%, HAuCl ₄ 3H ₂ O, Sigma-Aldrich), silver nitrate (99.0%, AgNO ₃ , Sigma-Aldrich), CTAB (99%, C ₁₉ H ₄₂ BrN, Sigma-Aldrich), hexadecylpyridinium chloride monohydrate (>98%, C ₂₁ H ₃₈ ClN H ₂ O, TCI), L-ascorbic acid (BioXtra, 99%) , C ₆ H ₈ O ₆ , Sigma-Aldrich), zinc nitrate hexahydrate (98%, Zn(NO ₃ ) ₂ 6H ₂ O, Sigma-Aldrich), 2-methylimidazole (99%, C ₄ H ₆ N _{2 )} , Sigma-Aldrich) and methyl alcohol (99.5%, Daejung) were purchased and used without further purification. Deionized water (18.2 MΩ cm at 25℃) purified by the Merck Millipore Direct Q3 UV water purification system was used for all washing and aqueous solution preparation. _{All glassware was treated with aqua regia (a mixture of HCl and HNO 3 in} a volume ratio of 3:1), washed repeatedly with deionized water and dried just before use.

2. Synthesis of gold nanorods

An aqueous solution of 100 mM CTAB (205 mL) was first prepared in a 250 mL Erlenmeyer flask at 30°C. A 100 mM CTAB solution (5 mL) was transferred to a 20 mL scintillation vial and mixed with an aqueous solution of 10 _{mM HAuCl 4 (125 μL).} Then, _{an ice-cold aqueous solution of 10} mM NaBH 4 (300 μL) was rapidly injected into the mixture and stirred at 1,150 rpm for 1 minute at room temperature. The light brown seed solution was aged at 30° C. for 20 minutes without stirring.

Aqueous solutions _{of 10 mM HAuCl 4} (10 mL), 10 mM AgNO ₃ (1.8 mL), 100 mM ascorbic acid (1.14 mL) and seed solution (240 μL) were sequentially added to 100 mM CTAB (200 mL) while stirring the solution at 30° C. at 500 rpm. did It was left on for 2 hours. The dark brown solution was then centrifuged twice at 8,000 rpm for 15 min. The gold nanorods were dispersed and stored in 50 mM CTAB (5 mL). It exhibited extinction at 781 nm with an intensity of about 1.0 after 40-fold dilution.

3. Coating Gold Nanorods on ZIF-8 (Rod@ZIF)

Encapsulation of gold nanorods in ZIF-8 first adjusted the concentration of the prepared nanorods to the extinction intensity of 25 and lowered the CTAB concentration to 1.5 mM. The nanorod solution (2.04 mL) was centrifuged at 8,000 rpm for 15 min, and the supernatant was discarded until 95 μL of the solution remained. Deionized water (3.06 mL) was added to the solution and mixed well. 24 mM Zn(NO ₃ ) ₂ .6H ₂ O (3mL) aqueous solution and the prepared nanorod solution (3mL) were sequentially injected into 1.32M 2-methylimidazole (3mL) aqueous solution contained in a 20mL scintillation vial. Stirring was continued for 5 minutes while stirring at 500 rpm at room temperature. It was left for 3 hours. The turbid solution was then centrifuged at 6,000 rpm for 15 min and the supernatant discarded. The light brown product was dispersed in methyl alcohol (10 mL) by vortexing and sonication for 5 min. Centrifuge at 5,000 rpm for 15 min and discard the supernatant. The product was dispersed and stored in methyl alcohol (15 mL). After a 5-fold dilution, it exhibited extinction at 806 nm with an intensity of about 1.0.

4. Etching Test of Rod@ZIF (Semi@ZIF, Sphere@ZIF and Empty ZIF)

Rod@ZIF was etched using _{HAuCl 4 and CTAB in methyl alcohol.} To find the optimal concentration of HAuCl _{4 ,} the test reaction was performed as follows. The Rod@ZIF solution (9.9 mL, extinction intensity = ~ 2.0) was centrifuged at 8,000 rpm for 10 min and the supernatant was discarded completely. The solvent medium was exchanged with 50 mM CTAB methyl alcohol (9.9 mL). The solvent-exchanged Rod@ZIF solution (1.5 mL) was transferred to a 2 mL tube (6 tubes total). Methyl alcohol solutions of 10 mM HAuCl ₄ (10, 13, 16, 19, 22 and 45 μL) were added to each tube and mixed well. The solution was transferred to a thermo mixer and mixed at 300 rpm for 30 minutes at 40°C. After that, the UV visible spectrum of each solution was immediately measured, and an appropriate volume of HAuCl ₄ was found to be 19 μL to obtain a spherical core in ZIF (Sphere@ZIF). _{The appropriate concentration of HAuCl 4} to obtain a spherical shape can depend on the nanorod dimensions used, and literature data can be referred to. Control experiments were performed using shell-free gold nanorods in methyl alcohol as mentioned in Rod@ZIF's etching.

5 Large-scale etching of Rod@ZIF (Sphere@ZIF)

The Rod@ZIF solution (19.3 mL, extinction intensity = ~2.0) was centrifuged and solvent exchanged using the method mentioned above. A methyl alcohol solution of 10 mM HAuCl ₄ (245 μL) was added to the Rod@ZIF solution in a 50 mL Erlenmeyer flask at 40° C. with stirring at 300 rpm, followed by stirring for 30 minutes. The pale pink solution was centrifuged at 8,000 rpm for 10 min and the supernatant was discarded. The product was well dispersed and stored in methyl alcohol (19.3 mL). It exhibited extinction at 528 nm with an intensity of ~0.80.

6. Regrowth of Sphere@ZIF

The Sphere@ZIF solution (1.5 mL, extinction intensity = ~ 0.80) was centrifuged at 8,000 rpm for 10 min and the supernatant was discarded completely. The solvent medium was exchanged to 100 mM CPC in methyl alcohol (0.2 mL). _{Methyl alcohol solutions of 10} mM HAuCl 4 (100 μL), 10 mM ascorbic acid (150 μL) and Sphere@ZIF (200 μL) were added sequentially to the 100 mM CPC solution (5 mL) in a 20 mL scintillation vial, lightly with each addition of chemicals by hand. Shake it. UV-visible spectra were measured every 2 minutes until clear. Simultaneously, aliquots (10 μL) were extracted and dried on a TEM grid for TEM imaging. To terminate the regrowth reaction and obtain the product, the solution after regrowth was quenched by two methods, respectively: (i) immediate centrifugation and (ii) immediate dilution and centrifugation. For method (i), immediately after 1 and 4 min of reaction, an aliquot of the product solution (1 mL) was centrifuged at 8,000 rpm for 5 s and the supernatant was discarded. The product was dispersed in methyl alcohol (1 mL) before TEM sampling. For method (ii), an aliquot of the product solution (1 mL) was diluted twice immediately after 1 and 4 minutes of reaction and the rest of the procedure was followed as in method (i).

7. Control experiment: encapsulation of gold spheroids

Nanospheres of ZIF-8 (Sphere@S-ZIF) and regrowth of Sphere@S-ZIF gold nanospheres stored in 100 mM CPC (10 mL, extinction intensity = ~0.8) were prepared according to a modified literature method. The surfactant in the nanospherical solution was first exchanged with 1.5 mM CTAB via centrifugation twice at 10,000 rpm for 20 min and the solution was concentrated 10-fold. 24 mM Zn(NO ₃ ) ₂ ·6H ₂ O (1 mL) aqueous solution and the prepared nanospherical solution (1 mL) were sequentially injected into 1.32 M 2-methylimidazole (1 mL) aqueous solution contained in a 20 mL scintillation vial. Stirring was continued for 5 minutes while stirring at 500 rpm at room temperature. It was left for 3 hours. The rest of the process is the same as Rod@ZIF. Sphere@S-ZIF (1.5 mL, extinction intensity = ~2.8) prepared for regrowth was used and redispersed in 100 mM CPC (200 µL). A methyl alcohol solution of 100 mM CPC (5 mL), 10 mM HAuCl ₄ (100 μL), 10 mM ascorbic acid (150 μL) and Sphere@S-ZIF (200 μL) was mixed sequentially in a 20 mL scintillation vial. The reaction was monitored through the UV visible spectrum and TEM sampling was performed.

8. Control Experiment: Regrowth of Rod@ZIF

The process was carried out as mentioned for the regrowth of Sphere@ZIF. Rod@ZIF (1.5 mL, extinction intensity = ~2.0) was used and redispersed in 100 mM CPC (200 μL). Aqueous solutions of 100 mM CPC (5 mL), 10 mM HAuCl ₄ (100 μL), 10 mM ascorbic acid (150 μL) and Rod@ZIF (200 μL) were sequentially mixed in a 20 mL scintillation vial. The reaction was monitored through the UV visible spectrum and TEM sampling was performed.

9. Control Experiment: Regrowth of Gold Nanorods

The regrowth of gold nanorods and nanospheres was performed in deionized water instead of methyl alcohol due to low solubility. The nanorod solution (72 µL, extinction intensity = ~41) was diluted with deionized water (1.4 mL) and redispersed in 100 mM CPC (200 µL). Aqueous solutions of 100 mM CPC (5 mL), 10 mM HAuCl ₄ (100 μL), 10 mM ascorbic acid (150 μL) and nanorod solution (200 μL) were mixed sequentially in a 20 mL scintillation vial. The reaction was monitored through the UV visible spectrum and TEM sampling was performed. The nanosphere solution (1.5 mL, extinction intensity = ~1.0) was concentrated to 200 μL. Aqueous solutions of 100 mM CPC (5 mL), 10 mM HAuCl ₄ (100 μL), 10 mM ascorbic acid (150 μL) and nanospheres (200 μL) were mixed sequentially in a 20 mL scintillation vial. The reaction was monitored through the UV visible spectrum and TEM sampling was performed.

10. Rod@ZIF and Sphere@ZIF Wash Treatment

Rod@ZIF (1.2 mL, extinction intensity = ~ 2.0) and Sphere@ZIF (1.2 mL, extinction strength = ~ 1.1) were each mixed with methyl alcohol (5 mL) and centrifuged at 8,000 rpm for 10 min. The supernatant (5 mL) was removed and redispersed in methyl alcohol. Each solution (10 μL) was sampled on a TEM grid. This process was repeated up to 6 times.

11. Characterization

_{A FEI Tecnai 12 transmission electron microscope using a LaB 6} emitter at 120 kV and a FEI Tecnai TF30ST transmission electron microscope using a ZrO/W (100) Schottky emitter at 300 kV were used for material analysis. A JEM-ARM200F Cs-calibrated scanning transmission electron microscope (JEOL) was used for elemental mapping. The sample solution (10 μL) was dropped and dried on a TEM grid (Electron Microscopy Sciences, CF400-CU) before TEM imaging. A JSM-7610F field emission scanning electron microscope (JEOL) was used for morphological analysis. The sample solution (20 μL) was dropped and dried on a silicon wafer (0.5 cm x 0.5 cm) before imaging. Spectroscopic measurements were performed as follows. UV-visible absorption measurements were performed using a Genesys 10S UV-Visible Spectrophotometer with a quartz cuvette (path length = 1 cm). A D8 Advanced A25 (BRUKER) was used for XRD measurements. A sample solution (20 μL) was dropped and dried on a silicon wafer (0.5 cm × 0.5 cm), and repeated 5 times to place sufficient particles for measurement. Nano ZS (Malvern Instrument Ltd.) was used to measure the DLS of the gold nanorod solution during etching. The sample holder was maintained at 40°C. BET surface area was analyzed using a Micromeritics ASAP 2020 Accelerated Surface Area and Porosity Measuring Analyzer (Micropore & Chemisorption). The sample solution was centrifuged twice at 8,000 rpm for 10 min and the supernatant was discarded completely. The residue was vacuum dried overnight and collected. Pretreatment of the powder was carried out at 60° C. under vacuum for 18 hours. The N ₂ adsorption and desorption were then measured at 77.5K.

12. Image Analysis

TEM images were first processed by ImageJ, an open source software, and curvature analysis was performed with Matlab code. Individual particles (gold nanorods, Rod@ZIF, Semi@ZIF and Sphere@ZIF) were selected and TEM images were converted to 8-bit. A Gaussian blur function with a sigma of 4 pixels was applied to the image. The contrast of these images was maximized through threshold adjustments to clarify the key shapes, creating a mask image with a white object and a black background. The mask images were processed through custom Matlab code to obtain the curvature values of the core particles. Curvature values were defined by contacting circles in Matlab code. As a result, the curvature distribution and color map were achieved.

By means of solving the above problems, the present invention can provide a method for controlling the shape of gold nanoparticles capable of controlling a chemical reaction in a limited nanometer space.

In addition, the present invention can control the shape of the gold nanorod particle inside by using ZIF-8, a porous nanoparticle, as a template, so that it can be used as a molecular sensor and drug carrier.

In addition, according to the present invention, branched gold nanoparticles grown in a confined space exhibit high surface area, electric field amplification, and high photothermal effect.

As such, those skilled in the art to which the present invention pertains will understand that the above-described technical configuration of the present invention may be implemented in other specific forms without changing the technical spirit or essential characteristics of the present invention.

Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims rather than the above detailed description, and the meaning and scope of the claims and their All changes or modifications derived from the concept of equivalents should be construed as being included in the scope of the present invention.

S10. The first step of preparing gold nanorods using hexadecyltrimethylammonium bromide (CTAB), chloroauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid}
S11. Step 1-1 to prepare a seed solution by mixing hexadecyltrimethylammonium bromide (CTAB) with chloroauric acid (HAuCl ₄ ) and sodium borohydride (NaBH _{4 )}
S12. The chloroauric acid (HAuCl ₄ ), silver nitrate (AgNO ₃ ), ascorbic acid, and the seed solution are added to hexadecyltrimethylammonium bromide (CTAB) to produce gold nanorods in Step 1-2
S20. A second method in which the prepared gold nanorods are reacted with 2-methylimidazole and an aqueous solution of zinc nitrate to coat zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods. step
S21. Step 2-1 of centrifuging the gold nanorod aqueous solution prepared in the first step (S10) to remove the supernatant, adding deionized water, and then mixing
S22. _{Zn(NO 3} ) ₂ .6H ₂ O and 2-methylimidazole were sequentially injected into the gold nanorods to which deionized water was added, followed by stirring to form ZIF-8 (zeolitic) on the surface of the gold nanorods. Step 2-2 coating the imidazolate framework-8)
S30. A third step of etching the coated gold nanorods to form gold nanospheres
S31. After centrifuging the solution from the coated gold nanorods and discarding the supernatant, step 3-1 of solvent exchange by stirring and mixing hexadecyltrimethylammonium bromide (CTAB)
S32. Step 3-2 of mixing chloroauric acid (HAuCl _{4 ) after the solvent exchange}
S40. The fourth step of re-growth by reducing the gold nanospheres
S41. After centrifuging the gold nano-spherical aqueous solution and discarding the supernatant, step 4-1 of solvent exchange by stirring and mixing hexadecylpyridinium chloride monohydrate (CPC)
S42. Step 4-2 of mixing chloroauric acid (HAuCl _{4 ) and ascorbic acid after the solvent exchange}

Claims (12)

A first step of preparing a gold nanorod using hexadecyltrimethylammonium bromide (CTAB) chlorauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid;}
A second method in which the prepared gold nanorods are reacted with 2-methylimidazole and an aqueous solution of zinc nitrate to coat zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods. step;
a third step of etching the coated gold nanorods to form gold nanospheres; and
A fourth step of reducing and re-growth of the gold nanospheres;
The regrowth of the fourth step is,
a step 4-1 of centrifuging the gold nanospherical solution, discarding the supernatant, and stirring and mixing hexadecylpyridinium chloride monohydrate (CPC) for solvent exchange; and
After the solvent exchange, _{the 4-2 step of mixing chloroauric acid (HAuCl 4} ) and ascorbic acid; controlling the shape of gold nanorod particles in the nanometer local space of ZIF-8 Way.
The method of claim 1,
The generation of gold nanorods in the first step is,
Step 1-1 to prepare a seed solution by mixing hexadecyltrimethylammonium bromide (CTAB) with chloroauric acid (HAuCl ₄ ) and sodium borohydride (NaBH _{4 );} and
The chloroauric acid (HAuCl ₄ ), Silver nitrate (AgNO ₃ ), ascorbic acid and the seed solution are added to hexadecyltrimethylammonium bromide (CTAB) to produce gold nanorods ZIF- characterized in that it is carried out by; A method of controlling the morphology of gold nanorod particles in a local space of 8 nanometers.
3. The method of claim 2,
The prepared gold nanorods,
A method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, characterized in that it has a length of 48 to 57.2 nm and a width of 13 to 15.3 nm.
The method of claim 1,
The coating of ZIF-8 on the surface of the gold nanorods in the second step is,
Step 2-1 of centrifuging the gold nanorod aqueous solution prepared in the first step (S10) to remove the supernatant, adding deionized water, and then mixing; and
_{Zn(NO 3} ) ₂ .6H ₂ O and 2-methylimidazole were sequentially injected into the gold nanorods to which deionized water was added, followed by stirring to form ZIF-8 (zeolitic) on the surface of the gold nanorods. A method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, characterized in that it is carried out by the 2-2 step of coating the imidazolate framework-8).
5. The method of claim 4,
The coated gold nanorods,
Gold nanorods in the nanometer local space of ZIF-8, characterized in that the length of the shell of the coated zeolitic imidazolate framework-8 (ZIF-8) is 139.4 to 161 nm, and the width is 112.3 to 140.3 nm A method of controlling the shape of a particle.
The method of claim 1,
The coated gold nanorods,
A method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, characterized in that the gold nanorod is located in the center of the inner center of the zeolitic imidazolate framework-8 (ZIF-8) branching type.
The method of claim 1,
The etching of the third step is,
A method of controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, characterized in that it is oxidized using chloroauric acid (HAuCl _{4 ) and hexadecyltrimethylammonium bromide (CTAB) to form a spherical shape.}
The method of claim 1,
The etching of the third step is,
a step 3-1 of centrifuging the solution from the coated gold nanorods, discarding the supernatant, and mixing and stirring hexadecyltrimethylammonium bromide (CTAB) to exchange the solvent; and
A method of controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, characterized in that it is performed by; step 3-2 of mixing chloroauric acid (HAuCl _{4 ) after the solvent exchange.}
The method of claim 1,
The regrowth of the fourth step is,
A method for controlling the shape of gold nanorod particles in a nanometer local space of ZIF-8, characterized in that reduction using chloroauric acid (HAuCl _{4 ) and ascorbic acid.}
delete A first step of preparing a gold nanorod using hexadecyltrimethylammonium bromide (CTAB) chlorauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid;}
The prepared gold nanorods were reacted with 2-methylimidazole and an aqueous solution of zinc nitrate to form zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods prepared in the form of rods. a second step of coating;
a third step of etching the coated gold nanorods to form gold nanospheres; and
A fourth step of reducing and re-growth of the gold nanosphere;
The regrowth of the fourth step is,
a step 4-1 of centrifuging the gold nanospherical solution, discarding the supernatant, and stirring and mixing hexadecylpyridinium chloride monohydrate (CPC) for solvent exchange; and
Molecules using gold nanorod particles in the nanometer local space of ZIF-8, characterized in that it is performed by; step 4-2 of mixing chloroauric acid (HAuCl _{4 ) and ascorbic acid after the solvent exchange} sensor.
A first step of preparing a gold nanorod using hexadecyltrimethylammonium bromide (CTAB) chlorauric acid (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO _{3 ) and ascorbic acid;}
The prepared gold nanorods were reacted with 2-methylimidazole and an aqueous solution of zinc nitrate to form zeolitic imidazolate framework-8 (ZIF-8) on the surface of the gold nanorods prepared in the form of rods. a second step of coating;
a third step of etching the coated gold nanorods to form gold nanospheres; and
A fourth step of reducing and re-growth of the gold nanosphere;
The regrowth of the fourth step is,
a step 4-1 of centrifuging the gold nanospherical solution, discarding the supernatant, and stirring and mixing hexadecylpyridinium chloride monohydrate (CPC) for solvent exchange; and
A drug using gold nanorod particles in a nanometer local space of ZIF-8, characterized in that it is carried out by; step 4-2 of mixing chloroauric acid (HAuCl _{4 ) and ascorbic acid after the solvent exchange} carrier.

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