KR101840948B1 - Nanocomposite, composition for coating comprising the same, apparatus for manufacturing nanocomposite, and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a nanocomposite, a coating composition comprising the same, and an apparatus and a method for manufacturing the nanocomposite. The nanocomposite of the present invention has excellent biocompatibility, antimicrobial properties and dispersibility. When coating a surface of various articles such as a medical instrument, an electronic device such as a touch panel, or automobile interior equipment by using the coating composition comprising the nanocomposite, a coating layer having excellent transparency is formed and excellent antimicrobial properties can be imparted. Moreover, according to the apparatus and method for manufacturing the nanocomposite of the present invention, the nanocomposite can be continuously manufactured through a simple and environmentally friendly process.

Description

TECHNICAL FIELD [0001] The present invention relates to a nanocomposite, a nanocomposite, a coating composition containing the nanocomposite, a nanocomposite, a coating composition containing the nanocomposite, and an apparatus and a method for manufacturing the nanocomposite.

The present invention relates to a nanocomposite, a coating composition containing the same, and an apparatus and a method for producing the nanocomposite.

Bacterial contamination on the surface can harm human health or damage various medical devices and systems. Previously, antibacterial agents such as silver, copper, and quaternary ammonium ions have been used to inhibit bacterial growth. Also, recently, as the use of antibacterial equipment has increased, research on nanocomposites including metal nanoparticles has been attempted. In addition, research on nanocomposites suitable for biomaterials carrying antibacterial and specific optical properties and carrying therapeutic or diagnostic reagents is underway.

Particularly, in the case of anisotropic nanocomposite, the contact surface of bacteria and metal is increased due to its large surface area, and at the same time, the ability to emit antibacterial components is also excellent.

As an existing method of producing an anisotropic nanocomposite, a chemical manufacturing method through a template or a seed is well known. The method has used very fine metal particles as a template or seed to grow different metals on a metal surface. The ultra fine metal particles can be continuously grown with a specific crystal orientation and can be induced in various hierarchical forms. Also, as a wet chemical production method, a method of using a high temperature, an ultrasonic wave, and a potential difference for a template and a surfactant has been reported previously.

In general, nanocomposites containing metal particles are required to have antimicrobial properties that can stably or continuously inhibit bacterial growth without any side effects in order to be used as a biopolymer for surface coating or deformation. However, most of the metal particles have poor compatibility with the polymer component, which makes it difficult to combine the metal particles with the polymer component. Accordingly, the use of the nanocomposite as the biopolymer is limited.

 Most anisotropic nanocomposites are prepared in wet chemical oxidation-reduction manufacturing batches in which templates and surfactants are present to ensure good suspension stability and yield. In order for the nanocomposite to form within the batch, metal ions must be reduced to metal atoms by a reducing agent. However, this method is not only complicated in the reaction and separation process, but can also be limited to the application in the biotechnology field.

Although the wet chemical steps as described above are somewhat limited in application to various bio-equipment, there are advantages in terms of selectivity and stability over other chemical processes. Thus, there remains a need in the manufacture of nanocomposites through wet chemical steps that still needs to be addressed in other aspects such as continuity, productivity, environmental friendliness and versatility.

The present application provides a nanocomposite having excellent antimicrobial and dispersing properties, a coating composition having excellent antibacterial properties and transparency, and the present application also relates to a manufacturing apparatus capable of producing the nanocomposite in a simple, environmentally friendly, And a process for producing the same.

The present application relates to nanocomposites. Exemplary nanocomposites of the present application include a shell comprising a seed comprising a first metal, a core comprising a second metal having a higher standard reduction potential than the first metal, and a biocompatible polymer, wherein the nanocomposite When the surface of various articles such as medical devices, electronic devices such as touch panels, or automobile interior equipments is coated using the coating composition including the nanocomposite by adjusting the fractal dimension value within a specific range, And at the same time an excellent antibacterial property can be imparted to the surface of the article.

The term " nano " in this application may refer to a size in nanometers (nm), for example, but is not limited to, a size of 1 to 1,000 nm. As used herein, the term " nanoparticle " may mean particles having an average particle size in nanometers (nm), for example, particles having an average particle size of 1 to 1,000 nm, But is not limited to.

Nanocomposites according to one embodiment of the present application include seeds, cores and shells. In one example, the nanocomposite may be a particle having a triple structure of seed-core-shell. For example, the nanocomposite may be produced by preparing the first metal particle to form a seed, reducing the second metal to the surface of the first metal particle to form a core surrounding the seed, and the biocompatible polymer To form a shell surrounding the core.

Quot; seed " means the innermost portion of the triple structure, the " core " means a portion surrounding the seed and existing between the seed and the shell of the triple structure, The " shell " refers to the outermost portion of the triple structure surrounding the core.

The term " enclosing " means that the outer circumferential surface of the particle is substantially covered. In the above, the outer circumferential surface is formed so as to cover substantially 50% or more, 60% or more , 70% or more, 80% or more, 90% or more, 95% or more, or 99% or more.

The seed may comprise a first metal, and the standard reduction potential value of the first metal may be less than 0.6V. For example, the first metal may have a standard reduction potential value of less than 0.55 V, less than 0.40 V, less than 0.38 V, less than 0.36 V, less than 0.35 V.

In the present specification, the term "standard reduction potential" means a potential when the activity of all chemical species participating in the oxidation-reduction reaction is 1 at 25 ° C., 1 M and 1 atm of electrolyte concentration, Means the value measured with the hydrogen electrode at 0.00 V. The larger the standard reduction potential between the two materials, the greater the reduction potential. As used herein, the term " reducing power " refers to the ability of any one of the substances participating in the oxidation-reduction reaction to oxidize itself and to reduce another substance during the oxidation-reduction reaction. Quot; means a substance which is easily oxidized.

In one example, the first metal may be a transition metal of Groups 3 to 12, for example, the first metal may be a Group 5-12, 6-12, or 8-11 transition metal . The transition metal exhibits excellent compatibility with a second metal and a biocompatible polymer which will be described later, and is easy to bind between the respective components, and thus the structural shape of the nanocomposite can be stably maintained, and the fractal of the nanocomposite Dimensional values can be easily adjusted. In addition, the nanocomposite according to the present application can be used for various purposes such as a therapeutic or diagnostic reagent because it can have magnetic and optical characteristics peculiar to a transition metal by including a first metal as a transition metal as a core.

For example, the first metal may include at least one selected from the group consisting of copper, nickel, cobalt, and iron, and may be, for example, copper, but is not limited thereto.

In one example, the core may comprise a second metal having a standard reduction potential value of 0.6 V or higher, for example, the second metal may be a standard of at least 0.65 V, at least 0.70 V, at least 0.75 V, or at least 0.79 V It may have a reduction potential value. By adjusting the standard potential value of the second metal to be larger than the standard potential value of the first metal, the core can be formed on the surface of the seed through the redox reaction. When a core containing a second metal having a standard potential in the above range is formed on the surface of the first metal seed by an oxidation-reduction reaction, the core may be formed to have a bunch shape, The composite may have a unique structural shape through the core, for example, the fractal value may be adjusted to within a range described below. Furthermore, the second metal may also function as an autocatalysis during redox reaction.

In one example, the second metal may include at least one selected from the group consisting of silver, gold, platinum, palladium, ruthenium, and rhodium and may be, for example, silver, but is not limited thereto.

The shell may comprise a biocompatible polymer. By including the biocompatible polymer, the shell can minimize the cytotoxicity caused by the metal present in the seed and the core, and can secure the excellent biocompatibility and antibacterial property of the nanocomposite. Accordingly, the nanocomposite can be used for various purposes in various fields related to the human body. The biocompatible polymer can also act as a reducing agent during the redox reaction of the first and second metals. Further, the biocompatible polymer can be prepared by maintaining the viscosity of the coating composition containing the nanocomposite at a predetermined level or higher, The workability of the composition can be improved.

The biocompatible polymer is not particularly limited as long as it is biocompatible and has antibacterial properties. Examples of the biocompatible polymer include natural polymers, aromatic or heterocyclic polymers, (meth) acrylic polymers, cationic conjugated polymers, polysiloxanes, natural polymers An amphoteric polymer, and a phenol or benzoic acid derivative.

In one embodiment, the biocompatible polymer is selected from the group consisting of, for example, Chitosan, Catechin, Flavonoids, Lactoferin, Lactoperoxidase, Phytoncide, Lysozyme ), Ovotransferrin, avidin, ovoflavoprotein, ovomucoid, cystatin, Nisin, pediocin, e-polylysine, polyphenols, polyhexamethylene guanidine hydrochloride, polyhexamethylene guanidine phosphate, polyhexamethylene biguanidine, polyhexamethylene biguanidine hydrochloride, polyhexamethylene biguanidine phosphate, polyvinyl pyridine, Poly-2-methyl-5-vinylpyridine, polyvinylpyrrolidone, and copolymers thereof, and may be, for example, chitosan Or, without being limited thereto.

The nano composite is, as described above, may have a unique structural shape, and in one example, the fractal dimension (Fractal Dimension, d _f) a value of the nanocomposite may be 1.6 to 2.8 days, for example, 1.7 To 2.6 or 1.9 to 2.5, and preferably from 1.6 to 2.2. The term " fractal dimension " in the present application means an index indicating shape information for arbitrarily shaped particles, for example, a larger fractal dimension value means that the shape of the particle is spherical, The smaller the dimension value, the more non-spherical it can be.

The fractal dimension value may be determined by the following general formula (1).

[Formula 1]

는 나노 복합체의 유효 밀도(Effective Density)를 나타낸다. 단, d_b는 1이 아니며, k는 반응 조건에 따라 적절히 변경될 수 있으며, 예를 들어, 10⁴ 이하의 정수일 수 있다. 또한, 상기 k 값의 하한은 0이 아닌 정수이면 특별히 제한되지 않으나, 예를 들어, 0.01 이상, 0.001 이상 또는 0.0001 이상일 수 있다.In the general formula (1), k represents a proportional constant, d _b represents a mobility equivalent diameter of the nanocomposite,

Represents the effective density of the nanocomposite. However, d _b is not 1, and k may be suitably changed according to the reaction conditions, and may be an integer of 10 ⁴ or less, for example. The lower limit of the k value is not particularly limited as long as it is a nonzero integer. For example, it may be 0.01 or more, 0.001 or more, or 0.0001 or more.

For example, if the value of the fractal dimension (d _f ) calculated in the general formula 1 has a value close to 1, it means that the shape of the particle has a linear one-dimensional shape, and if it has a value close to 3 Means that the shape of the particle has a spherical three-dimensional shape.

 Exemplary nanocomposites of the present application may have a non-spherical shape such as a bunch shape such as a grapevine by controlling the fractal dimension value of the nanocomposite within the above-mentioned range. Furthermore, when the nanocomposite of the present application is applied to a coating composition, the non-spherical structural shape can realize high transparency when coated. On the other hand, when the fractal dimension value is out of the above range, the shape of the particle becomes spherical or linear, and when the nanocomposite is applied to the coating composition, the transmittance of the coating layer may be lowered. In one example, the nanocomposite may be a nanocomposite-bound structure having at least one seed-core-shell structure.

The ionization tendency of the first metal may be greater than the ionization tendency of the second metal. The ionization tendency of the first metal is controlled to be larger than the second metal ionization tendency so that the second metal is maintained in a reduced state and the second metal in the reduced state acts as an active portion so that the core stably surrounds the seed . In addition, the second metal in the reduced state may act as an active moiety to be bonded to a biocompatible polymer described later.

The present application also relates to compositions for coating.

The coating composition of the present application may include the above-described nanocomposite, and the nanocomposite may be dispersed in the composition. Accordingly, the contents overlapping with those described in the above-mentioned nanocomposite will be omitted. The exemplary coating composition of the present application contains the above-described nanocomposite, exhibits excellent transparency when coated on the base material, and can maintain the texture or color of the base material as it is and can impart excellent antibacterial properties to the coating object.

The present application also relates to an apparatus for producing nanocomposites. The apparatus for producing a nanocomposite of the present application can be used in the production of the above-described nanocomposite, and therefore, the description of the parts overlapping with those described in the above-described nanocomposite will be omitted. According to the exemplary apparatus for producing a nanocomposite of the present application, the aforementioned nanocomposite can be continuously produced through a simple and environmentally friendly process.

Hereinafter, an apparatus for producing a nanocomposite of the present application will be described with reference to the accompanying drawings, and the attached drawings are illustrative, and the scope of the apparatus for manufacturing a nanocomposite of the present application is not limited by the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an exemplary nanocomposite production apparatus of the present application. FIG.

As shown in Fig. 1, the manufacturing apparatus of the present application includes a discharger 10 and a reaction tank 20. Fig.

The discharge unit 10 is a part for generating metal nanoparticles by spark discharge and spaced apart from each other by a predetermined distance to form a pair of conductive rods 3 to 12 containing transition metals And a power supply unit 12 for applying a voltage to the conductive rod 11.

The pair of conductive rods 11 are spaced apart from each other to form a gap. For example, a spark discharge occurs in the discharge unit 10, and metal nanoparticles are generated due to the high temperature locally generated between the conductive rods 11 due to the spark discharge. The term " gap " or " gap " as used in the present application means a gap between two parts that are moved or fixed. For example, the gap may be a space between a pair of conductive rods 11 .

The material constituting the conductive rod 11 is not particularly limited as long as it is a transition metal of Groups 3 to 12, and the contents overlapping with the first metal described in the above-described nanocomposite will be omitted.

The gap between the conductive rods 11, for example, the electrode gap which is the shortest distance between the conductive rods 11, decreases as the distance between the conductive rods 11 decreases. As the distance increases, Is required. In addition, if the electrode gap is narrow, the voltage required to generate the spark is reduced, but the short spark can cause misfiring by transmitting the minimum ignition energy to the mixer, so it is necessary to set an appropriate distance by experiment. In one example, the gap between the electrodes may be from 0.1 to 10 mm, but is not limited thereto.

The power supply unit 12 is a portion for applying a voltage to each of the conductive rods 11. In one example, the voltage applied from the power supply unit 12 to the conductive rods 11 is 2 to 5 kV, The amount of current may be from 0.5 to 5 mA, but is not limited thereto. For example, the voltage applied to the pair of conductive rods 11 can be controlled to be constant in the power supply unit 12. Thus, metal nanoparticles can be prepared with good supply stability by quantitatively supplying metal nanoparticles.

In one example, the power supply unit 12 may include an electric circuit for applying a high voltage to the conductive rod 11. The electric circuit has a constant voltage source structure composed of a high voltage supply (HV), an external capacitor (C) and a resistor (R), and is capable of switching a plurality of resistors, a plurality of capacitors, Can be used to control the size of the metal nanoparticles.

Although not shown, the manufacturing apparatus of the present application may include a gas supply device such as a carrier gas supply system and a flow meter such as an MFC (Mass Flow Controller). In addition, inert gas, oxygen or nitrogen can be quantitatively supplied at intervals between the conductive rods by the gas supply device and the flow meter.

Oxygen, and nitrogen that flow through the gap between the conductive rods when the high voltage is applied to the conductive rod 11, the transition metals of Groups 3 to 12 being vaporized or granulated by the spark discharge, May be introduced into a reaction vessel 20 to be described later along with one or more kinds of gas flows. For example, when a voltage is applied to the conductive rod 11 of the discharge unit 10, the metal is vaporized at a distance between the pair of conductive rods 11 of the discharge unit 10, and an inert gas or nitrogen Vaporized metal moved along the carrier gas, etc., is condensed as it goes beyond the above-mentioned interval, and thus metal nanoparticles are formed.

The particle diameter of the metal nanoparticles generated from the discharge unit 10 can be controlled according to the flow rate or the flow rate of the inert gas or nitrogen. For example, the particle size of the metal nanoparticles can be controlled within a range of 1 to 20 nm. Examples of the inert gas include, but are not limited to, argon (Ar), helium (He), and the like.

The reaction vessel 20 is included in the manufacturing apparatus for attaching the silver precursor and the biocompatible polymer to the metal nanoparticles to form a nanocomposite. FIG. 2 is a diagram schematically showing the formation process of a ternary nanocomposite in the reaction tank. As shown in FIG. 2, the metal nanoparticles generated in the gap between the conductive rods 11 are impregnated with the reaction tank, silver is precipitated on the surface of the metal nanoparticles by the oxidation-reduction reaction, and the biocompatible polymer . The reaction tank is filled with a solution containing a silver precursor and a biocompatible polymer. For example, the silver precursor may be silver nitrate (AgNO ₃ ).

In one example, the reaction tank 20 may further include a defoaming device 21. The bubble removing device 21 is not particularly limited as long as the metal nanoparticles generated in the gap between the conductive rods 11 are capable of removing bubbles generated by impregnating the reaction vessel 20, For example, it may be an ultrasonic irradiation apparatus. Since the bubbles can be formed by the inert gas or nitrogen introduced into the reaction tank together with the metal nanoparticles and the metal nanoparticles can flow out of the reactor again along the bubbles, It can act as a disturbing factor. In order to prevent this, the bubble removing device 21 removes the bubbles and can control so that the metal nanoparticles generated in the discharge part are completely impregnated into the reaction tank. Furthermore, when the bubble removing device 21 is used, the degree of reduction of the second metal can be increased.

As shown in FIG. 2, the apparatus for producing a nanocomposite according to the present application may further include a storage section 30. FIG.

For example, the solution may be a coating composition as described above. The solution may be a solution prepared by mixing the nanocomposite formed in the reaction tank and a solvent. As the solvent, for example, water or an organic solvent may be used without limitation, preferably an organic solvent containing a hydroxyl group in the molecular structure, for example, ethanol or methanol may be used. However, no.

The present application also relates to a method for producing nanocomposites. The method of manufacturing the nanocomposite of the present application can be performed by using the apparatus for producing a nanocomposite as described above, and therefore, the description of the parts overlapping with those described in the apparatus for producing a nanocomposite and a nanocomposite will be omitted. By way of exemplary nanocomposite manufacturing methods of the present application, nanocomposites can be continuously produced through a simple and environmentally friendly process.

Fig. 3 is a view showing an exemplary method for producing the nanocomposite of the present application. As shown in FIG. 3, the method for producing a nanocomposite of the present application includes the steps of generating transition metal nanoparticles and forming a nanocomposite.

The step of generating the transition metal nanoparticles may be performed in the discharging unit 10 of the apparatus for producing nanocomposites described above, and in one example, they are spaced apart from each other to form an interval, Applying a voltage to each of the pair of conductive rods including the transition metal and the conductive rod to generate transition metal nanoparticles from the pair of conductive rods.

In the step of generating the transition metal nanoparticles, when a high voltage is applied to the conductive rod 11, the transition metals of Groups 3 to 12 are vaporized or granulated by a spark discharge, And may be introduced into the reaction tank 20 according to a gas or nitrogen flow.

The step of forming the nanocomposite may be performed in the reaction tank 20 described above. In one example, the step of forming the nanocomposite includes immersing the transition metal nanoparticles generated in the step of generating the transition metal nanoparticles in a solution containing the silver precursor and the biocompatible polymer, and reacting .

In one embodiment, in the step of forming the nanocomposite, the reaction may be performed for 30 seconds to 300 seconds, for example, 50 seconds to 300 seconds, 80 seconds to 250 seconds, 100 seconds to 200 seconds, or 110 seconds 150 seconds. In the manufacturing method of the present application, by adjusting the reaction time to the above-mentioned range, the fractal dimension value of the nanocomposite can be controlled in the range of 1.6 to 2.8, and thus the prepared nanocomposite has excellent antibacterial and dispersibility And the coating composition comprising the complex can maintain excellent transparency. For example, if the reaction time is less than 30 seconds, the seed, core, and shell may not be sufficient to bind, and if the reaction time is 300 seconds or more, the core comprising the reduced second metal, It is difficult to control the shape.

Further, the reaction can be performed under, for example, ultrasonic irradiation conditions. As described above, by removing the bubbles by the ultrasonic waves, it is possible to control so that the generated transition metal nanoparticles are completely impregnated into the reaction tank, and further, the degree of reduction of the second metal can be increased.

The nanocomposite of the present application has excellent biocompatibility, antibacterial properties and dispersibility and can be used for coating surfaces of various articles such as medical devices, electronic devices such as touch panels or automobile interior equipments by using the coating composition comprising the nanocomposite , A coating layer having excellent transparency can be formed and excellent antimicrobial activity can be imparted to the surface of the article. Further, according to the apparatus and method for producing a nanocomposite of the present application, a nanocomposite can be continuously produced through a simple and environmentally friendly process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an exemplary nanocomposite production apparatus of the present application. FIG.
Fig. 2 is a diagram schematically showing the formation process of a bunch-shaped nanocomposite.
Fig. 3 is a view showing an exemplary method for producing the nanocomposite of the present application.
4 is a graph showing a result of measuring the particle size distribution of the copper nanoparticles generated in the discharge part.
5 is a scanning electron microscope image of the nanocomposite prepared in the example.
6 is an energy dispersive spectroscopic image of the nanocomposite prepared in Example 2. Fig.
7 is a scanning electron microscope image of the nanocomposite prepared in Example 3. Fig.
FIG. 8 is a transmission electron microscope image of silver nanoparticles prepared under ultrasonic irradiation conditions from the first solution and the second solution without introducing the copper nanoparticles into the reaction tank.
Fig. 9 shows the absorbance results of the nanocomposites prepared in Examples 1 to 3 measured by UV-vis spectra.
10 to 12 are low magnification, high magnification SEM images of the nanocomposites collected on glass substrates in Examples 1 to 3, respectively.
13 is an energy dispersive spectroscopy (EDX) image of nanocomposites collected on glass substrates in Examples 1 to 3
14 is a graph showing FTIR spectra of pure chitosan nanoparticles electrosprayed and chitosan-bound copper-silver nano-blanks prepared in Example 3. Fig.
FIG. 15 is a photograph of the nanocomposite prepared in Examples 1 to 3 coated on a glass substrate on a white paper printed with "Cu-Ag"
16 is a photograph of a mobile display device, a nanoparticle coating of Comparative Example 1 on white printed paper, a chitosan coating, and a copper-silver nano-blanket coated glass disk surrounded by chitosan prepared in the Examples.
17 shows the results of the evaluation of the antibacterial activity of the nanocomposite prepared in the examples and comparative examples of the present application.
FIG. 18 is a graph showing the growth profile of the medium in the presence of copper-silver nanotubes surrounded by chitosan prepared in Examples 1 to 3 and Comparative Example, and the illustration of FIG. 18 is a graph showing the growth profiles of E. coli before and after treatment of the nano- . ≪ / RTI >
19 shows the results of measurement of antimicrobial activity of the nanocomposite prepared in Examples and Comparative Examples using the Kirby-Bauer disk diffusion method.
20 is a graph showing the results of evaluating antimicrobial activity of purified spherical silver nanoparticles at different mass concentrations (0 to 90 占 퐂 / mL) of copper-silver nanotubes.
21 is a graph showing the production of intracellular reactive oxygen species in the bacterial cell suspension treated with the nano-bran, pure chitosan, silver and copper-silver samples prepared in Example 2. Fig.
Figure 22 shows the results of measuring the cytotoxicity in HEK 293 cells according to different mass concentrations (0-90 [mu] g / mL) of pure chitosan particles, purified copper-silver samples and nano-bunches prepared in Examples 1-3.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present application is not limited by the following description.

Example 1

The nanocomposites were prepared according to the method of FIG. 3 using the apparatus of FIG.

Specifically, as shown in FIG. 3, nitrogen gas was passed through the discharge unit 10. The flow rate of the nitrogen gas was maintained at 3.0 L / min by a mass flow controller (Tylan, US) and passed between a pair of electrodes made of a copper (Cu) rod (diameter 3 mm, length 10 mm, Nilaco, Japan) . At this time, the spacing between the pair of electrodes was 1 mm, and gas-phase copper nanoparticles were prepared at a temperature of about 6000 ° C. by applying a spark to the electrode. Specifically, the spark was applied to the electrode at a resistance of 0.5 M ?, a capacitance of 1.0 nF, a current of 1.2 mA, a voltage of 3.2 kV, and a frequency of 320 Hz.

The generated copper nanoparticles were transferred to a reaction tank 20 filled with the first solution and the second solution along with the nitrogen gas. The first solution was prepared by dissolving 85 mg of silver nitrate (205052, Sigma-Aldrich, US) in 5 ml of deionized water. The solution was filtered through a tube peristaltic pump (323Du / MC4, Watson-Marlow Bredel Pump, (Sigma-Aldrich, US) was added to the reaction solution while maintaining a flow rate of 1 mL / mL / min. The second solution was prepared by adding 0.25 g of chitosan (41796, 25 ml, and filled into the reactor 20 while maintaining a flow rate of 2.08 ml / min through the tube peristaltic pump. An ultrasound probe (VCX 750, 20 kHz, Sonics & Materials Inc., US) was immersed in the solution in the reaction tank 20 and operated as the ultrasonic wave irradiator by applying a power density of 10 W / mL. The active portion of the probe is a 1.3 cm ² rounded surface of the bottom of the probe. In the reaction vessel 20, the copper nanoparticles, the first solution and the second solution were reacted under ultrasound irradiation for 30 seconds to prepare a nanocomposite. At the beginning of the reaction, the pale yellow solution turned bright brown, indicating the reduction of silver. The gaseous copper particles acted as seeds, and they were able to dynamically accept silver ions on the seed particles, resulting in the formation of copper-silver nanotubes. Hereinafter, the term " nano-bran " can be used in the same sense as " nanocomposite " The reduction rate of silver ions (Ag ⁺ / Ag ⁰ = 0.78 V) is faster than the reduction rate of copper ions (Cu ^{2 +} ), so that the reduction of silver ions occurs more easily than copper particles. The silver layer formed on the surface of the copper particles in the reaction acts as an active site for the additional deposition of silver.

The prepared nanocomposite was sprayed by using an electric atomizing device composed of a tube peristaltic pump (07522-30, Masterflex, US), a stainless steel nozzle having a diameter of 0.3 mm, and a power supply device (10 / 40A, Trek, US) , And collected on a glass substrate (7059, Corning, US) while maintaining an injection rate of 16 μl / min.

The fractal dimension value of the prepared composite was calculated to be 2.2.

Example 2

The nanocomposite was prepared in the same manner as in Example 1, except that the reaction was carried out in the reaction tank for 120 seconds.

The fractal dimension value of the prepared composite was calculated as 2.0.

Example 3

The nanocomposite was prepared in the same manner as in Example 1, except that the reaction was carried out in the reactor for 300 seconds.

The fractal dimension value of the prepared composite was calculated to be 1.6.

Comparative Example 1 - Preparation of copper nanoparticles

A nanocomposite was prepared in the same manner as in Example 1, except that the step of reacting in the reaction tank was not carried out.

The fractal dimension value of the fabricated composite was calculated to be 2.6.

Comparative Example 2 - Preparation of nanoparticles

A nanocomposite was prepared in the same manner as in Example 1, except that silver nanoparticles were prepared under ultrasonic irradiation conditions without passing copper particles through the reaction tank.

The fractal dimension value of the fabricated composite was calculated as 3.0.

Comparative Example 3 - Preparation of copper-silver nanoparticles

A nanocomposite was prepared in the same manner as in Example 1, except that only the first solution was filled in the reaction vessel.

The fractal dimension value of the composites was calculated to be 1.9.

Comparative Example 4

A nanocomposite was prepared in the same manner as in Example 1 except that an ultrasonic irradiation device was not provided in the reaction tank.

The fractal dimension value of the composites was calculated to be 2.3.

Measurement result

The Particle Size Distribution of the copper particles was measured using a Scanning Mobility Particle Sizer (SMPS), 3936, TSI, US to determine the concentration, average particle size, and standard deviation Respectively. Copper particles specimens formed on the carbon-coated copper grid produced by spark discharge in the gas phase were analyzed using a transmission electron microscope (TEM, JEM-3010, JEOL, Japan). The copper particles were deposited on a grid using a commercial aerosol collector (NPC-10, HCT, Korea).

4 is a graph showing a result of measuring the particle size distribution of the copper nanoparticles generated in the discharge part. 4 is an image of a transmission electron microscope of copper nanoparticles.

As shown in FIG. 4, the concentration of copper nanoparticles was 3.10 × 10 ⁷ paticles / cm ³ , the diameter was 14.2 nm, and the standard deviation was 1.40. TEM observation also shows that the primary copper particles having an average particle size of about 3.3 nm are agglomerated and have a particle size of about 14 nm, which means that the primary particles collide with each other after they are formed near the spark.

To understand the morphology changes during the reaction, different forms of copper-silver nanostructures were observed with increasing reaction times. For this purpose, particles prepared at reaction times of 30, 120, and 300 seconds were sampled and observed using a scanning electron microscope to confirm the morphology change.

5 is a scanning electron microscope (SEM, JSM-6500F, JEOL, Japan) image of the nanocomposite prepared in the example.

As shown in Fig. 5, small bunches having different contrast (different materials) and sizes were observed in the initial stage of silver reduction. After 5 minutes, these structures grew, and the subsequent reaction led to the formation of any structure of copper-silver bran (e. G., Silver continuously covered on pre-formed particles). Due to the autocatalysis action of silver previously formed on the trapped copper particles, a greater amount of silver (I) reduction occurred site selectively on the surface of the copper than on the surface of the captured copper particles, as shown in FIG.

6 is an energy dispersive spectroscopic analysis (EDX, JED-2300, JEOL, Japan) image of the nanocomposite prepared in Example 2. Fig. The EDX elemental maps of silver and copper corresponding to the image of the scanning electron microscope are well matched and indicate the specific location of the silver and copper in the scanning electron microscope image.

7 is a transmission microscope (TEM) image of the nanocomposite prepared in Example 3. Fig.

As shown in Fig. 7, the transmission electron microscopic result is also consistent with the scanning electron microscopic observation. In addition, the transmission electron microscope image shows a different contrast between the specimenized particles, indicating that different materials combine to form particles. The darker contrast sample particles have a (111) plane due to a 0.21 nm face-centered cubic (Fcc) copper lattice, while the brighter contrast covering the darker contrast is from a (111) plane with a lattice spacing of 0.23 nm . In addition, the different parts were combined with each other to form a single body, and the successive deposition of silver on the captured copper particles and pre-formed silver surface was clearly observed. As the reaction time increased, the size of the fabricated structure increased due to the continuous inflow of copper and the deposition of silver, resulting in larger anisotropic bimetallic structures. The different movements of the silver deposition of the incoming copper and the preformed silver surface could maintain the formation of anisotropic silver during the reaction. For comparison, silver (I) reduction was performed under ultrasonic irradiation conditions without introduction of copper particles as in Comparative Example 2. FIG. 8 is a transmission electron microscope image of silver nanoparticles produced under ultrasound irradiation conditions from the first solution and the second solution without introducing copper nanoparticles into the reaction tank in Comparative Example 2. FIG. As shown in FIG. 8, it was confirmed that almost spherical silver particles were produced under the same reaction conditions, and it was found that the influx of copper into the silver (I) -chitronic reaction cell was very important for the formation of the copper- silver nano- I can see that it is.

It can be seen from the spectrum of the nanostructure that the bonding of silver on copper causes shift of absorption of light in the visible light region. FIG. 9 shows the absorbance results of the nanocomposites prepared in Comparative Example 1 and Examples 1 to 3, as measured by UV-vis spectra (330, Perkin-Elmer, USA). Referring to FIG. 9, as the reaction time increases, a blue shift of 430 nm at 590 nm in the absorption spectrum is shown, which means that the size and morphology of the nanocomposite are changed. The existence of copper and silver can be confirmed from two peaks. As the reaction time increases, the increase in the intensity of the absorption peak appears to be due to the increase in the size of the nanocomposite. The narrowing of the absorption peak width means that the fraction of silver in the nanocomposite increases as the reaction time increases ≪ / RTI > and also indicates that the nanostructures are well dispersed.

10 to 12 are low magnification, high magnification SEM images of the nanocomposites collected on glass substrates in Examples 1 to 3, respectively.

As shown in Fig. 10, when the reaction time was set to 30 seconds (Example 1), nanostructures produced due to collisions between small particles were combined. This is because of the significant increase in diffusion (about 10 ³ times) when the small particles move from the liquid phase (aerosol) to the gas phase (aerosol) by electro-spraying of the solution, Since the collision between the two can be significantly increased. Increasing the reaction time from 120 seconds to 300 seconds as in Examples 2 and 3 leads to significant size and shape changes. As shown in FIG. 11, in the case of the reaction time of 120 seconds (Example 2), the metal particles connected to the chitosan matrix had an elongated shape and the reaction time was 300 seconds (Example 3) Sized structures were formed and the size variation was increased compared to particles prepared with a reaction time of 120 seconds. This indicates that particles of larger size are aggregated and a fairly large agglomerated structure is formed during the electrospray process.

13 is an energy dispersive spectroscopic (EDX) image of the nanocomposite collected on a glass substrate in Examples 1-3. As shown in FIG. 13, it was confirmed that as the reaction time was increased, the fraction between silver and chitosan increased.

FIG. 14 shows the results of FT-IR measurement using FT-IR measurement equipment (IFS 66 / S, Bruker Optics, Germany) of the nanocomposite and chitosan collected on a glass substrate. From the results of the FT-IR measurement, it was confirmed that the nanobunts were well bound to chitosan by the bond between the amino or hydroxy group of chitosan and the silver attached to the copper nanoparticles.

FIG. 15 is a photograph of the nanocomposite prepared in Examples 1 to 3 coated on a glass substrate on a white paper printed with "Cu-Ag" The antimicrobial coating is not only very important for general hygiene but also is a functional coating that can prevent infection from physical contact of electronic devices such as touch panels. Therefore, the transparency of the nano bran surrounded by chitosan was tested. As shown in Fig. 15, the coating of the copper-silver nanotubes surrounded by chitosan had different transparency with increasing reaction time, and the "Cu-Ag" text was visually confirmed. This indicates that the coating is transparent. The thickness of the coating on the glass plate was about 60 mu m. Relative opacity E of the coating was measured with a handheld chroma meter (CL-200A, Konica Minolta Americas Ins., US). As a result, for Examples 1 to 3, the E values were measured as 3.5, 10.82, and 25.73, respectively, and the haze values were measured as 1.31%, 3.82%, and 4.66%, respectively. Figure 16 is another example of testing transparency including a mobile touch screen panel.

17 shows the results of the evaluation of the antibacterial activity of the nanocomposite prepared in the examples and comparative examples of the present application. The antimicrobial activity was evaluated by measuring the degree of inhibition of growth of bacteria (E. coli 25922), specifically, E. coli was proliferated in Luria-Broth for one day at 37 ° C temperature condition, The optical density was measured while maintaining the temperature, and the number of bacteria was normalized to about 10 ⁶ cfu / mL. 50 mL of a broth aliquot was poured onto the surface of the nano-bran prepared in Example and covered with glass for 10 to 300 minutes at 37 占 폚. After a period of time, the specimens were washed with 1.0 wt% Tween Solution and 0.9 wt% sodium chloride solution, 40 μl aliquots were extracted, transferred to a Nutrient Agar Plate, Lt; RTI ID = 0.0 > 37 C < / RTI > for 16 hours. Minimum Inhibitory Concentration was obtained using E. coli and S. aureus in agar medium 24 hours after incubation.

As can be seen from FIG. 17, it was confirmed that the nano-branes prepared in the Examples can significantly inhibit the growth of E. coli. During the evaluation, the water expands the chitosan and increases the migration of metal ions to the culture medium through the chitosan matrix and inhibits bacterial growth. Colony-forming units (cfu / mL) per unit volume of the measured E. coli medium decreased significantly with increasing nano-bunch concentration. Less than 50% of bacteria were found in all cases at a concentration of 90 μg / mL after a 1.5 hour incubation time. In particular, as in Example 2, at a reaction time of 120 seconds, 50% proliferation was inhibited at a concentration of 10 mu g / mL after only 1 hour of incubation. Corrosion of the nano-benthic surface causes antimicrobial activity, which is due to the diffusion of moisture from the surface of the nano-bran surface to support the antibacterial behavior. Therefore, the smaller size nanobunks with a reaction time of 120 seconds were compared with those with a reaction time of 300 seconds and exhibited better antimicrobial activity. This is because the diffusion of metal ions (mostly silver ions) and particles in wet media is inversely proportional to the size of the particles. This also coincides with the growth profile of the nano bran in Fig. Therefore, it was confirmed that the control of the reaction time of the nano-blanche production can control the growth rate of the bacteria as well as the growth of the bacteria.

19 shows the results of measurement of antimicrobial activity of the nanocomposites prepared in Examples and Comparative Examples using Kirby-Bauer Disc Diffusion Method. As shown in Fig. 19, the suppression region around the disc became clearer and clearly observed when the carbon fiber disc on which the nano-blanket was deposited was placed on the medium.

FIG. 20 is a graph showing the results of evaluating antimicrobial activity of the purified spherical silver nanoparticles prepared in Comparative Example 2 and the copper-silver nanobunes prepared in Example 2 at different mass concentrations (0 to 90 μg / mL). 20 shows the susceptibility constant Z (mL / ㎍) of the nano bran prepared in Example 2, and the spherical silver nanoparticles having approximately the same average lateral dimension of about 94 nm And the antimicrobial activity of the nano bran against Escherichia coli was further evaluated. The illustration of Fig. 20 is the result of the evaluation of the antimicrobial activity of the nanocomposite. In conclusion, more active antimicrobial materials have a high susceptibility constant, Z, which means that the bacteria have greater sensitivity to these materials. The average Z values of the bacteria in relation to the copper-silver nanotubes and silver nanoparticles were measured at 0.0745 mL / 및 and 0.0297 mL / 각각 respectively.

In addition, the antibacterial properties against the nano-benthic E. coli and Staphylococcus aureus 25923 prepared in Example 2 were evaluated using pure chitosan, silver nanoparticles and copper-silver nanoparticle samples (10-90 μg / mL , Side dimension of about 90 nm), and the antibacterial activity was evaluated using the minimum inhibitory concentration (MIC), a standard measurement method for determining the bactericidal effect of the antibacterial agent.

MIC ([mu] g / mL) Chitosan Silver nanoparticles
(Comparative Example 2) Copper-silver nanoparticles
(Comparative Example 3) Copper-silver-chitosan nanobranch
(Example 2) E. coli 50.1 45.8 16.5 8.6 S. aureus 52.2 45.8 17.3 9.9

As a result, it was confirmed that the nano-bran of Example 2 exhibited an MIC value lower than the MIC value of the chitosan, silver nanoparticle, and copper-silver nanoparticle sample, and thus exhibited excellent antimicrobial activity. Furthermore, both antimicrobial activities showed no significant difference in the two bacterial cells. 21 is a graph showing the production of intracellular reactive oxygen species in the bacterial cell suspension treated with the nano-bran, pure chitosan, silver nanoparticle and copper-silver nanoparticle sample prepared in Example 2. Fig. As shown in FIG. 21, in order to support the antibacterial activity, levels of reactive oxygen species (ROS) for the nano-blanks of the examples were measured and compared with pure chitosan, silver nanoparticles and copper-silver nanoparticles samples. This is because the analysis of reactive oxygen species is used as a collective marker of superoxide anion, hydroxyl radical and hydrogen peroxide which serve as an index of cellular oxidative stress .

As shown in FIG. 21, through the measurement of fluorescence intensity due to the response of bacterial cells to the nano-blanche of Example 2, the production of intracellular reactive oxygen species was induced by H ₂ DCFDA (2`, 7`-Dichlorodihydrofluorescein Diacetate) .

21, after 4 hours of incubation, larger reactive oxygen species values than the other samples were detected in the nano-benthic treated bacterial cells because of the higher amount of reactive oxygen species resulting from the nano-benthic treatment, Structure and / or intracellular system was further damaged. These results therefore support the generation of free radicals for the inhibition of bacterial growth.

Because polymer-coated metal particles are also attracting attention in biopharmaceuticals, the cytotoxicity of nanobunts is further evaluated. Fig. 22 shows the results of the measurement of the concentration of the chitosan particles in HEK 293 cells according to different mass concentrations (0-90 [mu] g / mL) of pure chitosan particles, the copper-silver nanoparticle samples prepared in purified Comparative Example 3 and the nano- It is the result of measuring toxicity.

The nano-bran were cultured in human embryonic kidney cells (HEK 293) for 24 hours and analyzed using 3- (4,5-Dimethylthiazol-2-yl) -Diphenyltetrazolium Bromide (MTT) Cell viability was measured. As shown in FIG. 22, the pure copper-silver nanoparticles to which chitosan was not bound showed a cell viability of about 17% at a concentration of 90 μg / mL, whereas the chitosan- Nano-benthic cells showed cell viability of 74% or more at a concentration of 90 μg / mL. Though pure copper-silver nanoparticles released metal and clearly contributed to cytotoxicity, the release fraction of nanobunes surrounded by chitosan did not significantly affect the cells, because of the biocompatibility of the chitosan layer. That is, from the above results, it was confirmed that the nanocomposite according to the present application has superior biocompatibility to pure metal nanoparticles while having an excellent antibacterial effect against bacteria.

On the other hand, in order to confirm the collection amount of the copper particles, the particle distribution in the case of the presence and absence of the ultrasonic wave irradiation device was measured through the example and the comparative example 4. [ As a result, in the case of the examples, most of the incoming copper particles in the ultrasonic irradiation process were trapped in the aqueous solution with a capture efficiency of 96.8%. This is because the inside of the bubble tears before reaching the surface of the solution, causing the hydrousolization of almost all the copper particles.

10: discharge unit
11: conductive rod
12:
20: Reactor
21: Air bubble removing device
30:

Claims (15)

A seed comprising a first metal having a standard reduction potential value of less than 0.6 V; And a second metal surrounding the seed and having a standard reduction potential value of 0.6 V or higher; And a shell surrounding the core, the shell comprising a biocompatible polymer,
Wherein the first metal includes at least one selected from the group consisting of copper, nickel, cobalt, and iron,
Wherein the second metal comprises at least one selected from the group consisting of silver, gold, palladium, ruthenium, rhodium, and platinum, and wherein the fractal dimension value is 1.6 to 2.8. The nanocomposite according to claim 1, wherein the ionization tendency of the first metal is larger than the ionization tendency of the second metal. delete delete delete The biocompatible polymer of claim 1, wherein the biocompatible polymer is selected from the group consisting of a natural polymer, an aromatic or heterocyclic polymer, a (meth) acrylic polymer, a cationic conjugated polymer, a polysiloxane, a natural polymer mimetic polymer, and derivatives of phenol and benzoic acid, A nanocomposite comprising at least one. The biocompatible polymer of claim 1, wherein the biocompatible polymer is selected from the group consisting of Chitosan, Catechin, Flavonoids, Lactoferin, Lactoperoxidase, Phytoncide, Lysozyme, Ovotransferrin, Avidin, Ovoflavoprotein, Ovomucoid, Cystatin, Nisin, Pediocin, e-polylysine (e- polylysine, polylysine, polyphenol, polyhexamethylene guanidine, polyhexamethylene guanidine hydrochloride, polyhexamethylene guanidine phosphate, polyhexamethylene biguanidine, polyhexamethylene biguanidine hydrochloride, polyhexamethylene biguanidine phosphate, polyvinylpyridine, poly-2 Methyl-5-vinylpyridine, polyvinylpyrrolidone, and copolymers thereof. The coating composition according to any one of claims 1, 2, 6, and 7, wherein the nanocomposite is dispersed. delete delete delete delete A pair of conductive rods spaced apart from each other and spaced from each other and including a first metal including at least one selected from the group consisting of copper, nickel, cobalt, and iron, and a conductive rod, Generating transition metal nanoparticles from a pair of conductive rods; And
And immersing the generated transition metal nanoparticles in a solution containing a silver precursor and a biocompatible polymer and reacting them to form a nanocomposite. 14. The method of claim 13, wherein the reaction is performed for 30 seconds to 5 minutes. 14. The method of claim 13, wherein the reaction is performed under ultrasonic irradiation conditions.

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