KR102609429B1 - Method for producing nanoparticles surface-substituted with zwitterion - Google Patents

Abstract

The present invention relates to a method for producing nanoparticles whose surface is substituted with amphoteric ions, and more specifically, to nanoparticles with excellent dispersibility and low foreign matter adsorption ability by substituting the surface of the nanoparticle with an amphoteric compound.

Description

Method for producing nanoparticles surface-substituted with zwitterions {METHOD FOR PRODUCING NANOPARTICLES SURFACE-SUBSTITUTED WITH ZWITTERION}

The present invention relates to a method for producing nanoparticles whose surface is substituted with amphoteric ions, and more specifically, to nanoparticles with excellent dispersibility and low foreign matter adsorption ability by substituting the surface of the nanoparticle with an amphoteric compound.

Nanoparticles are applied in various fields such as electronics, information storage, and catalysts, and have recently been widely used in the medical and pharmaceutical fields, including optoelectronics, sensing, and imaging, as well as in vivo drug delivery systems and contrast agents.

Nanoparticle-based drug delivery systems can prevent drug decomposition and concentrate drug delivery in specific cells, thereby achieving effective treatment and reducing side effects, so research on this is actively underway.

However, since nanoparticles have a large surface area and generally high surface energy, they are prone to biofouling, where various plasma proteins and salts attach to the surface. Due to biofouling, nanoparticles cannot circulate in the blood for a long time and are easily eliminated by the liver, or the possibility of aggregation between nanoparticles increases.

To prevent this phenomenon, prior art WO2007-146680A proposed a method of preventing adsorption of foreign substances such as proteins by attaching a zwitterionic compound to the surface of nanoparticles.

The prior art discloses that a water film can be formed on the surface of a nanoparticle by substituting a zwitterionic compound having a structure in which positive charges (+) and negative charges (-) coexist simultaneously on the surface of the nanoparticle. The water film can prevent foreign substances such as proteins from being adsorbed on the surface of the nanoparticles.

However, the zwitterionic compound substituted in the nanoparticle has a relatively high molecular weight, and due to steric hindrance between the zwitterionic compounds, there is a problem in that the bonding density of the zwitterionic compound per unit surface area of the nanoparticle is low. .

The stability of the water film is reduced due to the low binding density of the zwitterionic compound bound to the nanoparticle, which may increase the probability of adsorption of foreign substances such as proteins, and may also reduce dispersibility, making it a drug carrier that must have long-term circulation in vivo. There are still difficulties in using it as a contrast agent, etc.

Republic of Korea Patent Publication No. 10-1631311 (2016.06.10)

The purpose of the present invention to solve the above problems is to replace the surface of the nanoparticles with an amphoteric ionic compound, thereby producing nanoparticles surface-substituted with an amphoteric ionic compound that can suppress the phenomenon of biofouling on the surface of the nanoparticles. is to provide. Specifically, the aim is to provide a method for manufacturing nanoparticles that can increase the bonding density of zwitterionic compounds bound to nanoparticles, thereby improving the stability of the water film and suppressing the adsorption of various foreign substances present in the living body.

The present invention includes a first modification step of preparing nanoparticles surface-substituted with amine groups by treating nanoparticles with an aminosilane-based compound; and

A second modification step of covalently bonding the nanoparticles surface-substituted with the amine group with a sultone-based compound;

A method for producing nanoparticles surface-substituted with zwitterions containing a is provided.

According to one aspect of the present invention, the aminosilane-based compound may be a compound having the structure of Formula 1 below.

[Formula 1]

Si(R ₁ )(R ₂ )(R ₃ )-L-NH ₂

(R ₁ , R ₂ and R ₃ are each independently a (C ₁ -C ₆ ) alkoxy group or a hydroxy group, and L is a substituted or unsubstituted (C ₁ -C ₁₀ ) alkylene group.)

According to one aspect of the present invention, the solvent used in the step of treating nanoparticles with an aminosilane-based compound in the first modification step may be a co-solvent of distilled water and ethanol.

According to one aspect of the present invention, the sultone-based compound may be a compound having the structure of Formula 2 below.

[Formula 2]

(n is 0 to 2, is a single bond or double bond.)

According to one aspect of the present invention, the nanoparticles surface-treated with zwitterions may be modified with 0.1 to 5 parts by weight of an aminosilane-based compound and 0.1 to 5 parts by weight of a sultone-based compound based on 100 parts by weight of the nanoparticles. .

According to one aspect of the present invention, the zwitterionic nanoparticles may have an absolute zeta potential of 20 mV or less in the pH range of 7 to 9.

According to the manufacturing method of the present invention, zwitterionic compounds can be substituted at high density on the surface of nanoparticles, and through this, the attachment of foreign substances such as proteins to the surface of the nanoparticles can be more effectively suppressed.

In addition, nanoparticles prepared by the above method can stably create a water film and have excellent dispersibility in body fluids or blood.

Figure 1 is a schematic diagram showing the manufacturing process of nanoparticles surface-substituted with zwitterions according to the present invention.
Figure 2 is a graph measuring the thermogravimetric change of nanoparticles surface-substituted with zwitterions prepared in Examples 1 and 2 using thermogravimetric analysis (TGA).
Figure 3 is a Raman spectroscopy image of the silica particles of Comparative Example 2 and the nanoparticles surface-substituted with zwitterions of Example 1.
Figure 4 is an
Figure 5 is a transmission electron microscopy (TEM) image showing the size and shape of nanoparticles surface-substituted with zwitterions.
Figure 6 is a zeta potential image showing the change in surface charge value according to pH of a solution containing nanoparticles surface-substituted with zwitterions.
Figure 7 is a Quartz Crystal Microbalance (QCM) graph measuring the size of the water film formed on the surface-substituted nanoparticles with zwitterions of Example 1 according to the change in pH.
Figure 8 (a) shows the hydrodynamic particle size of the silica particles of Comparative Example 2, the nanoparticles surface-substituted with the aminosilane-based compound of Comparative Example 1, and the nanoparticles surface-substituted with zwitterions of Example 1 using dynamic light scattering method. (B) is an image measured through Dynamic Light Scattering, and (B) is an image measuring the hydrodynamic particle size according to pH in Example 1.
Figure 9 shows ultraviolet-visible spectroscopy (UV) showing the stability of silica particles of Comparative Example 2, nanoparticles surface-substituted with an aminosilane-based compound of Comparative Example 1, and nanoparticles surface-substituted with zwitterions of Example 1 by solution. -vis spectrophotometer) graph.
Figure 10 is a modification showing the degree of BSA protein adsorption on a substrate coated with silica particles of Comparative Example 2, nanoparticles surface-substituted with an aminosilane-based compound of Comparative Example 1, and nanoparticles surface-substituted with zwitterionic ions of Example 1. This is a Quartz Crystal Microbalance (QCM) graph.

Hereinafter, the present invention will be described in more detail through specific examples or examples including the attached drawings. However, the following specific examples or examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the invention.

Additionally, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to also include the plural forms, unless the context clearly dictates otherwise.

In addition, 'nanoparticles' used in the specification and appended patent claims refer to nanoscale particles with a diameter of less than 1000 nm. In some embodiments, the nanoparticles may have a diameter of 300 nm or less, as defined by the National Science Foundation.

Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Nanoparticles surface-substituted with zwitterionic ions differ from ordinary nanoparticles surface-substituted with cationic or anionic compounds. The surface charge of nanoparticles can change into positive and negative charges depending on the pH value, and can change into positive and negative charges in blood and body fluids. Within a similar neutral pH value, the particles have a total charge of 0 and have high dispersibility due to stable electrostatic attraction with water molecules.

Additionally, by replacing the nanoparticles with an amphoteric ionic compound, a water film may be formed on the surface of the nanoparticles. This is an effect exerted due to the specificity of the charge of the zwitterionic compound, and is a phenomenon in which water molecules strongly aggregate in the zwitterionic compound and appear on the surface of the nanoparticle.

The water film can be formed larger in a solution in which some salt is dissolved, such as inside a living body, than in distilled water. By forming a water film on the surface of the hydrophilic nanoparticles, the interaction between foreign substances and the hydrophilic nanoparticles is thermodynamically reduced, thereby preventing foreign substances such as proteins from being adsorbed to the nanoparticle surface, thereby reducing the dispersibility of the nanoparticles. This can be improved. However, since the water film that exists on the surface of nanoparticles is proportional to the density or concentration of the zwitterionic compound, if the surface density is low, the water film can be easily destroyed by changes in the external environment. Therefore, for the formation of a strong water film, zwitterionic ions are needed. The surface density of the compound must be increased.

Accordingly, the present invention primarily reacts a low molecular weight first functional compound with nanoparticles at high density, and then secondarily reacts with a second compound capable of reacting with the low molecular weight first functional compound. By doing so, nanoparticles with an increased surface density of zwitterionic compounds were manufactured and a strong water film was formed, thereby preventing protein adsorption on the surface of the nanoparticles, and the present invention was completed.

In addition, the method of producing nanoparticles surface-substituted with zwitterionic ions by dividing them into the first and second steps is to produce zwitterions on the surface of the nanoparticles, rather than the conventional method of first synthesizing zwitterions and depositing them on the nanoparticles. It has the advantage of being able to be combined more densely.

The method for producing nanoparticles according to the present invention includes a first modification step of treating nanoparticles with an aminosilane-based compound to produce nanoparticles surface-substituted with amine groups; and a second modification step of covalently bonding the nanoparticles surface-substituted with the amine group to a sultone-based compound.

Hereinafter, the first reforming step will be described in detail.

The nanoparticles of the present invention may have a diameter of 10 nm to 1000 nm, specifically 10 nm to 300 nm, and more specifically 50 nm to 200 nm in diameter, but are not limited thereto. Additionally, the nanoparticles may be, but are not limited to, spherical nanoparticles.

The material of the nanoparticles may be metal, ceramic, or polymer, and is not limited as long as it is a material that can be used in living organisms.

Polymers that can be used in nanoparticles may be biocompatible polymers, for example, polylactide, polylactide-glycolide copolymer, polycaprolactone, or polyethylene glycol.

The metal that can be used in nanoparticles may be a biocompatible metal and may be titanium, stainless steel, iron, platinum, or gold.

Ceramics that can be used for nanoparticles may be calcium phosphate, silica, titania, alumina, or zirconia.

As a specific example, a material that can be used for nanoparticles may be silica nanoparticles that have excellent biocompatibility and have a reactive group on the surface. The silica nanoparticles have a simple manufacturing process and have the advantage of being able to be mass-produced at low cost.

In the first step, the nanoparticles are surface-substituted with an aminosilane-based compound, so that amine groups can be modified on the surface of the nanoparticles.

The aminosilane-based compound may be a compound having the structure of Formula 1 below.

[Formula 1]

Si(R ₁ )(R ₂ )(R ₃ )-L-NH ₂

R ₁ , R ₂ and R ₃ are each independently a (C ₁ -C ₆ ) alkoxy group or a hydroxy group, and L is a substituted or unsubstituted (C ₁ -C ₁₀ ) alkylene group.

R ₁ , R ₂ and R ₃ included in Formula 1 may each independently be a functional group such as a (C ₁ -C ₆ ) alkoxy group or a hydroxy group.

When L is substituted (C ₁ -C ₁₀ ), at least one methylene unit of the alkylene group is replaced with a carbonyl (C=O), ester (COO), amino (NH), amide (CONH) or ether (O) group. It means something that can be replaced.

As the nanoparticles are replaced with amine groups, they can form subsequent covalent bonds with compounds containing functional groups such as carboxyl groups, hydroxy groups, and sultone groups.

Specifically, in the aminosilane-based compound of Formula 1, L may be a substituted or substituted (C ₁ -C ₁₀ ) alkylene group.

In Formula 1, R ₁ , R ₂ and R ₃ functional groups are alkoxy groups and L is an unsubstituted (C ₁ -C ₁₀ ) alkylene group. Examples of compounds include aminomethyltrimethoxysilane and aminoethyltrimethoxy. Silane, aminopropyltrimethoxysilane, aminobutyltrimethoxysilane, aminopentyltrimethoxysilane, aminohexyltrimethoxysilane, aminoheptyltrimethoxysilane, aminooctyltrimethoxysilane, aminononyltrimethoxysilane, Aminodecyltrimethoxysilane, Aminomethyltriethoxysilane, Aminoethyltriethoxysilane, Aminopropyltriethoxysilane, Aminobutyltriethoxysilane, Aminopentyltriethoxysilane, Aminohexyltriethoxysilane, Aminohep Tyltriethoxysilane, aminooctyltriethoxysilane, aminononyltriethoxysilane, aminodecyltriethoxysilane, etc., preferably aminoethyltriethoxysilane, aminopropyltriethoxysilane, and aminobutyltriethoxysilane. It could be silane.

In Formula 1, R ₁ , R ₂ and R ₃ functional groups are hydroxy groups and L is an unsubstituted (C ₁ -C ₁₀ ) alkylene group. Examples of compounds include aminomethylsilanetriol, aminoethylsilanetriol, amino It may be propylsilanetriol, aminobutylsilanetriol, aminophethylsilanetriol, aminohexylsilanetriol, aminoheptinsilanetriol, aminooctylsilanetriol, aminononylsilanetriol, aminodecylsilanetriol, etc. Preferably, it may be aminomethylsilanetriol, aminoethylsilanetriol, or aminopropylsilanetriol, but is not limited thereto.

The reaction solvent may be water, alcohol, or a co-solvent thereof. The alcohol may be a (C ₁ -C ₄ ) alcohol such as methanol, ethanol, or propanol. Preferably, the reaction solvent may be a co-solvent of water and alcohol, and water and alcohol are mixed at a weight ratio of 2:1 to 1:2. It may have happened. By using the co-solvent, the nanoparticles can be uniformly dispersed in the reaction solvent, which may be preferable.

When a mixture of water and alcohol in a weight ratio of 2:1 to 1:2 is used as a reaction solvent, compared to using only alcohol or water, the weight of the amino silane-based compound on the surface of the nanoparticle is 1.5 times more, preferably About 1.5 to 3 times more deposition can be achieved.

In the first modification step, the content of the aminosilane-based compound mixed with the nanoparticles is 0.1 to 5 parts by weight, preferably 0.2 to 4 parts by weight, more preferably, based on 100 parts by weight of the nanoparticles. may be 0.3 to 3 parts by weight. By mixing the aminosilane-based compound in the above weight parts, the nanoparticles can be surface-substituted with the aminosilane-based compound at high density, and the content of unreacted aminosilane-based compounds is minimized, allowing the subsequent purification process to be carried out efficiently. It can be. As a result, unnecessary reactions with sultone-based compounds introduced in the second modification step can be prevented, making the purification process simpler, and agglomeration between zwitterionic compounds on the surface of the nanoparticles can be prevented. there is.

The temperature of the reaction conditions in the first reforming step may be 10 to 50°C, specifically 20 to 40°C, and the reaction time may be 1 hour to 60 hours, specifically 2 hours to 10 hours, but is not limited thereto. .

After completion of the first modification step, the mixed solution can be centrifuged to separate the reaction product, nanoparticles surface-substituted with amine groups, from the supernatant. The separation process is performed multiple times to separate nanoparticles surface-substituted with amine groups from unreacted compounds and solvents, and through a drying process, pure solid powder of nanoparticles surface-substituted with amine groups can be obtained.

Next, the second reforming step of the present invention will be described in detail. In the second modification step, nanoparticles surface-substituted with amine groups are covalently bonded with sultone-based compounds to produce nanoparticles surface-substituted with zwitterionic compounds.

The sultone-based compound may be a compound having the structure of Formula 2 below.

[Formula 2]

(n is 0 to 2, is a single bond or double bond.)

The sultone-based compound may be, for example, 1,3-propane sultone, 1,4-butane sultone, or 1,3-propene sultone, and is preferably 1,3-propane sultone or 1,3-propene. It may be sulton.

The content of the sultone-based compound for the nanoparticles surface-substituted with amine groups may be 0.1 to 5 parts by weight of the sultone-based compound per 100 parts by weight of the nanoparticles surface-substituted with amine groups, and preferably 0.2 to 4 parts by weight. , more preferably 0.3 to 3 parts by weight. By mixing the sultone-based compound in the above weight parts, all amine groups present on the surface of the nanoparticle can react with the sultone-based compound and be converted into zwitterions.

The reaction solvent may be water, (C ₁ -C ₄ ) alcohol, or a co-solvent thereof. Preferably, the reaction solvent may be water.

The temperature of the reaction conditions in the second reforming step may be 30 to 80°C, specifically 40 to 70°C, and the reaction time may be 1 hour to 60 hours, specifically 2 hours to 10 hours, but is not limited thereto. .

Preferably, the aminosilane-based compound added in the first reforming step and the sultone-based compound added in the second reforming step may be greater than 1:1 and less than 1:3 in molar ratio. More preferably, the sultone-based compound is added in an excessive amount compared to the aminosilane-based compound so that all amine groups present on the surface of the nanoparticle react with the sultone-based compound, so that the surface of the nanoparticle can be replaced with a high density of zwitterions. .

Accordingly, the zwitterionic compound is attached to the surface of the nanoparticle at high density, and a water film can be formed very stably on the surface of the nanoparticle. As a result, foreign substances such as proteins can be prevented from being adsorbed on the nanoparticle surface. In addition, the agglomeration phenomenon between nanoparticles is reduced due to the water film layer, and the degree of dispersion can be improved.

After completion of the second modification step, the mixed solution can be centrifuged to separate the nanoparticles surface-substituted with zwitterions, which are reaction products, from the supernatant. The separation process can be performed multiple times to separate nanoparticles surface-substituted with zwitterions from unreacted compounds and solvents.

Optionally, after completion of the second reforming step, a washing step may be further included, consisting of a (C ₁ -C ₄ ) alcohol washing step and a water washing step.

After the separation and washing steps, a solid powder of nanoparticles surface-substituted with pure zwitterions can be obtained through a drying process.

According to one aspect of the present invention, the zwitterionic nanoparticles may have an absolute zeta potential of 20 mV or less in the pH range of 7 to 9.

Nanoparticles surface-substituted with zwitterions may have an absolute zeta potential value of 20 mV or less within the pH range of 7 to 9, more specifically, within the pH range of pH 7 to 8, which is the pH range in vivo. As the absolute value of has a low value, the adsorption of foreign substances such as proteins is significantly reduced.

The present invention will be described in more detail below based on examples and comparative examples. However, the following Examples and Comparative Examples are only one example to explain the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Measurement of physical properties]

1. Zeta potential

Zeta potential was measured using Horiba's SZ-100. As measurement conditions, a sample of nanoparticles diluted to 1 mg/ml in distilled water was prepared, and the sample was added at an amount of 200 μl for measurement.

2. Evaluation of stability in solution of nanoparticles surface-substituted with zwitterions

A dispersion solution was prepared by dispersing nanoparticles surface-substituted with zwitterions, amine-functionalized nanoparticles, and silica particles at 0.1 mg/ml each in growth media containing 10% distilled water (DW), 1X PBS, and FBS. , the initial visible light transmittance of the state of the dispersion solution was measured using UV-vis. Afterwards, the stability of the first solution was measured by centrifuging the dispersion solution at 500 rpm for 1.5 minutes. The above process was repeated three times to calculate the change in visible light transmittance for each particle to evaluate the stability of the prepared nanoparticles in solution.

3. Evaluation of protein adsorption of zwitterionic nanoparticles

To evaluate protein adsorption on the nanoparticle surface, each particle was coated on a QCM electrode three times using spin coating. After coating, the electrode was placed in a BSA (bovine serum albumin) solution and an FBS (fetal bovine serum) solution for 10 minutes each, and the protein adsorbed on the electrode was quantitatively analyzed through QCM.

[Example 1]

1. Amino silica nanoparticle manufacturing steps

100 parts by weight of silica particles with a particle size of 100 nm were added to a mixed solution prepared by mixing triple distilled water and ethanol in a 1:1 volume ratio and dispersed for 10 minutes using a sonicator. 3 parts by weight of aminopropyltriethoxysilane (3-Aminopropyl)triethoxysilane was added to the mixed solution in which the silica particles were dispersed, and then stirred at 500 rpm for 6 hours at 25°C to form amino silica coated with aminopropyltriethoxysilane. Nanoparticles were prepared. After stirring, the mixed solution was removed using centrifuge, and the obtained amino silica nanoparticles were purified twice in ethanol solvent. Afterwards, the purified amino silica nanoparticles were dried in a vacuum oven at 50°C to prepare dried amino silica nanoparticles.

2. Zwitterionic nanoparticle manufacturing steps

100 parts by weight of the amino silica nanoparticles were added to tertiary distilled water and dispersed using a sonicator. 3 parts by weight of 1,3-propanesultone was added dropwise to the toluene in which the amino silica nanoparticles were dispersed at 60°C for 4 hours while stirring at 500 rpm. At this time, the temperature of the solution was reacted at 60°C in an oil bath for 4 hours to prepare zwitterionic nanoparticles. After the reaction, the zwitterion nanoparticles were washed once with ethanol and twice with distilled water and then dried in a vacuum oven at 80°C to prepare silica nanoparticles surface-substituted with dried zwitterions.

For the nanoparticles surface-substituted with zwitterions prepared above, the surface charge and water film size according to pH were measured and listed in Table 1, and the BSA adsorption was measured and listed in Table 2.

[Example 2]

The same procedure as in Example 1 was carried out, except that amino silica nanoparticles were prepared using only ethanol instead of the mixed solution prepared by mixing tertiary distilled water and ethanol in a 1:1 volume ratio.

[Comparative Example 1]

100 parts by weight of silica particles with a particle size of 100 nm were added to a mixed solution prepared by mixing triple distilled water and ethanol in a 1:1 volume ratio and dispersed for 10 minutes using a sonicator. To the mixed solution in which the silica particles were dispersed, 3 parts by weight of aminopropyltriethoxysilane (3-Aminopropyl)triethoxysilane was added based on 100 parts by weight of the silica particles, and then stirred at 500 rpm for 6 hours at 25°C to obtain aminopropyl triethoxysilane. Triethoxysilane-coated amino silica nanoparticles were prepared. After stirring, the mixed solution was removed using centrifuge, and the obtained amino silica nanoparticles were purified twice in ethanol solvent. Afterwards, the purified amino silica nanoparticles were dried in a vacuum oven at 50°C to prepare dried amino silica nanoparticles.

For the amino silica nanoparticles prepared above, the surface charge according to pH was measured and listed in Table 1, and the degree of BSA adsorption was measured and listed in Table 2.

[Comparative Example 2]

The same silica nanoparticles as in Example 1 were used, but the surface charge of the untreated silica nanoparticles was measured according to pH and is listed in Table 1, and the adsorption degree of BSA and FBS was measured and shown in Table 2.

Zeta potential value (mV) for nanoparticle surface according to pH pH 6 pH 7 pH 8 pH 9 Example 1 +20 +18 -5 -23 Comparative Example 1 +42 +37 +29 +21 Comparative Example 2 -66 -65 -70 -72 QCM value ΔF (Hz) for water film size as a function of pH pH 8 pH 8.5 pH 9 Example 1 -387 -770 -727

BSA adsorption QCM value (Hz) on nanoparticle surface BSA FBS Example 1 106 11 Comparative Example 1 471 160 Comparative Example 2 250 313

Table 1 and Figure 6 show the zeta potential value and size of the water film on the nanoparticle surface according to pH. In Example 1, it is +20 mV at pH 6 and -23 mV at pH 9. Accordingly, it can be seen that the charge changes around neutral pH as the surface of the nanoparticle is replaced with zwitterions. On the other hand, in the case of Comparative Examples 1 to 2, it can be confirmed that there is no change in charge according to pH changes because they do not contain zwitterions.

Table 1 and Figure 7 are Quartz Crystal Microbalance (QCM) graphs and numerical values measuring the size of the water film formed on the surface-substituted nanoparticles with zwitterions of Example 1 according to the change in pH.

Referring to Table 1, it was measured as -387 ΔF at pH 8.0 and -770 ΔF at pH 8.5, indicating that pH 8.0 has a higher density than pH 8.5. Accordingly, the size of the water film is inversely proportional to the density, and it can be seen that pH 8.5 is larger than pH 8.0. Therefore, it can be seen that the size of the water film formed on the nanoparticles surface-substituted with zwitterions in Example 1 is affected by pH. You can check it.

Figure 8 (a) is a diagram measuring the hydraulic particle size of Comparative Examples 1 and 2 and Example 1 through Dynamic Light Scattering (DLS), and (b) is a diagram showing the hydraulic power according to pH of Example 1. This is a drawing measuring the particle size.

When measuring the hydraulic particle size with the DLS, it can be seen in (a) of Figure 8 that Example 1 has a larger diameter than Comparative Examples 1 and 2, which means that the size of the water film of Example 1 is larger than that of Comparative Example 1 or It suggests something greater than 2. Additionally, in (b) of Figure 8, it can be seen that the diameter measured by DLS at pH 8 is larger than pH 4 or pH 6.

In conclusion, from Tables 1 to 2 and Figures 6 to 8, it can be seen that the size of the water film of the zwitterionic nanoparticles of Example 1 changes depending on pH, of which the size of the water film varies from pH 8.0 to pH 9.0. It can be confirmed that it is the largest.

Table 2 and Figure 10 show the degree of adsorption of BSA (bovine serum albumin) in Examples and Comparative Examples measured by QCM, and it can be observed that Example 1 has the lowest BSA adsorption. This is an effect caused by the water film formation of the nanoparticles in Example 1, and can have a significant effect of preventing BSA from being adsorbed on the surface of the nanoparticles by the water film surrounding the surface of the nanoparticles.

In addition, when comparing the TGA analysis of the zwitterion nanoparticles of Example 1 and the amphoteric nanoparticles of Example 2 in Figure 2 (a), the weight% of zwitterions in Example 1 is the weight% of Example 2. You can see that the difference is about twice that of the value.

This means that when ethanol and third distilled water are mixed at a content ratio of 1:1, aminopropyltriethoxysilane is added to the silica particles, compared to when only ethanol is used as the solvent used in preparing the mixed solution in which the silica particles are dispersed. This suggests deposition at a high content.

Meanwhile, referring to FIG. 2 (b), compared to the silica particles of Comparative Example 2, the peak of the zwitterionic nanoparticles prepared in Examples 1 and 2 was shown to decrease at about 3500 cm ^-1 , indicating that the peak was present in the silica particles. It indicates that the silanol group has been replaced with aminopropyltriethoxysilane.

Figure 3 is a Raman spectroscopy image to confirm the chemical bond of Example 1 and Comparative Example 2. In Example 1 of FIG. 3, the SO ₃ ^- group present at the end of the zwitterion was confirmed in the 1040 cm ^-1 range, and the peak of the CH ₂ group that was not present in Comparative Example 2 was found in the 2800 to 3000 cm ^-1 range. By checking, it can be confirmed that zwitterions are bound to the surface of the silica nanoparticle.

Figure 4 is an .

That is, the 168.5 eV peak is a peak that does not exist in Comparative Examples 1 and 2, through which it can be confirmed that zwitterions were deposited on the surface of the silica nanoparticles.

In addition, Figure 9 is an evaluation of the stability of zwitterionic nanoparticles in solution of the nanoparticles of Examples and Comparative Examples in PBS and Growth media, and shows a relative comparison of the change in permeability of Example 1 after three centrifuges. It was confirmed that the change in UV-VIS transmittance was lower than that of Examples 1 to Comparative Examples 2. This indicates that Example 1 has better dispersibility and stability than Comparative Examples 1 to 2, and it can be confirmed that the dispersibility is high even in biological solutions.

It was confirmed that when the absolute zeta potential value was less than 20 mV, a water film of nanoparticles surface-substituted with zwitterions was formed, and thus dispersibility increased and adsorption of foreign substances decreased.

As described above, the present invention has been described with specific details and limited embodiments, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the field to which the present invention belongs is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

Claims (6)

A first modification step of preparing nanoparticles surface-substituted with amine groups by treating nanoparticles with an aminosilane-based compound represented by the following formula (1); and
A second modification step of covalently bonding the nanoparticles surface-substituted with amine groups with a sultone-based compound represented by the following formula (2);
A method for producing nanoparticles surface-substituted with zwitterions, comprising:
[Formula 1]
Si(R ₁ )(R ₂ )(R ₃ )-L-NH ₂
(R ₁ , R ₂ and R ₃ are each independently a (C ₁ -C ₆ ) alkoxy group or a hydroxy group, and L is a C ₁ -C ₁₀ alkylene group.)
[Formula 2]

(n is 0 to 2, is a single bond or double bond.) delete According to paragraph 1,
A method for producing nanoparticles surface-substituted with zwitterions, wherein the solvent used in the step of treating the nanoparticles with an aminosilane-based compound in the first modification step is a co-solvent of distilled water and ethanol. delete According to clause 1,
The nanoparticles surface-treated with zwitterions are nano particles surface-substituted with zwitterions, which are modified with 0.1 to 5 parts by weight of an aminosilane-based compound and 0.1 to 5 parts by weight of a sultone-based compound based on 100 parts by weight of the nanoparticles. Method for producing particles. According to paragraph 1,
The zwitterionic nanoparticles are a method of producing nanoparticles surface-substituted with zwitterionic ions having an absolute zeta potential of 20 mV or less in the pH range of 7 to 9.