KR101613779B1 - Localized surface plasmon resonance sensor with plasmonic probe functionalized by graphene oxide, method for preparing the same, and method and apparatus for detecting aromatic volatile organic compounds using the same - Google Patents

Abstract

Localized surface plasmon resonance (LSPR) sensors are fabricated by functionalizing the plasmonic probe metal nanoparticles with graphene oxide, which is used for the detection of aromatic volatile organic compounds. Accordingly, the binding force can be increased through pi-pi stacking between the aromatic volatile organic compound having a low affinity and the metal nanoparticle probe. In addition, by observing changes in the LSPR characteristics of a single plasmonic turbidimetry using a darkfield microscope, aromatic volatile organic compounds can be detected with high reproducibility and sensitivity. In addition, unlike the prior art, it is possible to simplify the manufacturing steps of the substrate, and by analyzing at the unit particle level, the volume of the sample used in the analysis is significantly reduced, so that a small amount of actual sample can be simply analyzed.

Description

TECHNICAL FIELD [0001] The present invention relates to a local surface plasmon resonance (LSPR) sensor having a plasmonic probe functionalized with graphene oxide, a method for producing the same, and a method and apparatus for detecting an aromatic volatile organic compound using the sensor , method for preparing the same, and method and apparatus for detecting aromatic volatile organic compounds using the same}

The present invention relates to a localized surface plasmon resonance (LSPR) sensor having a plasmonic probe functionalized with graphene oxide, a method for producing the same, and an aromatic volatile organic compound detection system using the sensor .

Generally, metal nanoparticles of nanometer (nm) size (for example, 100 nm or less) are collectively oscillated by electrons in the nanoparticle conduction band due to light of a specific frequency (wavelength) Dipole characteristics. As a result, the metal nanoparticles strongly absorb and scatter light in the corresponding frequency (wavelength) region, which is referred to as Localized Surface Plasmon Resonance (hereinafter, referred to as LSPR).

The extinction characteristics of metal nanoparticles with respect to external incident light, that is, the intensity and frequency (wavelength) of absorption and scattering band are determined depending on the type, size and shape of the metal nanoparticles. In addition, the absorption and scattering wavelengths are greatly influenced by the change in the refractive index of the surrounding environment of the metal nanoparticles, that is, the surface of the metal nanoparticles. By using such properties, biomolecules and chemicals Sensor field and so on.

The scattering and absorption by LSPR of metal nanoparticles can be measured by simple transmission spectroscopy without complex optical equipment such as prisms or diffraction gratings. In addition, the LSPR of metal nanoparticles is not sensitive to temperature, has a high detection speed, is detectable by a label-free method, and has an advantage of observing environmental changes of a material by an optical method . In addition, the ability to observe single nanoparticles allows flexibility in the design of LSPR sensors because of their high sensitivity and ability to control LSPR characteristics through nanoparticles of various shapes, sizes, and compositions.

On the other hand, Aromatic Volatile Organic Compounds are a generic term for liquid or gaseous organic compounds having a benzene ring among organic substances having a very high vapor pressure at room temperature. They are easily evaporated into the atmosphere due to their low boiling point and are commonly used in the living environment, such as liquid fuels, paraffin, building materials, laundry solvents, paints, pesticides.

Representative aromatic volatile organic compounds include toluene, benzene, ethylbenzene, xylene, styrene, and the like. These aromatic volatile organic compounds are mainly absorbed by the human body through respiration and skin, and it can cause dyspnea, lethargy, headache, vomiting, etc. in acute middle-aged Germany, and hematological disorders, anemia etc. in chronic Germany. Because of these risks, it is very important to develop technologies that can detect and observe aromatic volatile organic compounds that are widely used throughout life. One of these techniques is the detection method using the LSPR characteristics of metal nanoparticles.

Non-Patent Document 1 is an example of detection of a directional volatile organic compound using a conventional LSPR. In this document, aromatic volatile organic compounds are randomly adsorbed on the surface of various types of metal nanoparticles and then detected using an LSPR sensor.

However, according to the research results of the present inventors, in the case of the above-mentioned technology, it is inconvenient to synthesize various types of nanoparticles, especially nanoparticles having a complex structure, and to manufacture a large number of substrates in order to detect a substance have. In addition, it exhibits low reproducibility and sensitivity due to random adsorption between a high concentration sample and a plasmonic turbidimetry, and it is disadvantageous in that it requires a large volume of sample to be measured since it is not based on single particle measurement .

Accordingly, there is a need to develop an aromatic volatile organic compound detection system capable of detecting a small amount of a sample even though a complex nano structure is synthesized and a large number of substrates are not required, and the binding force between the metal nanoparticles and the aromatic volatile organic compound is high .

A vapor sensor array using multiple localized surface plasmon resonance bands in a single UV-vis spectrum K.-J. Chen, et al., Talanta (2010), 81, 1670-1675

Embodiments of the present invention are to solve the above-mentioned problems and provide a system that can easily detect an aromatic volatile organic compound with high sensitivity using local surface plasmon resonance phenomenon.

Specifically, by providing a technique of functionalizing metal nanoparticles as plasmonic probes with graphene oxide, it is possible to form metal nanoparticles by the chemical bonding (pi-pi stacking) between the metal nanoparticle probe and the aromatic volatile organic compound, It is possible to increase the affinity between volatile organic compounds and to increase the sensitivity and reproducibility of the signal while significantly reducing the volume of the sample used for the analysis by measuring at a single particle level, A local surface plasmon resonance (LSPR) sensor having a monstrous stagnation, a manufacturing method thereof, and a method and apparatus for detecting an aromatic volatile organic compound using the sensor.

In embodiments of the present invention, in one aspect, a local surface plasmon resonance (LSPR) sensor is provided that includes a plasmonic probe that is functionalized by binding of graphene oxide to metal nanoparticles. LSPR) sensor.

In an exemplary embodiment, the metal nanoparticles are positively charged, the graphene oxide is negatively charged, and the metal nanoparticles are coupled to the graphene oxide by electrostatic interaction.

In an exemplary embodiment, the metal nanoparticle size is 10-100 nm, preferably 20-80 nm.

In an exemplary embodiment, the graphene oxide size is 200 nm or less.

In an exemplary embodiment, the local surface plasmon resonance (LSPR) sensor is one in which metal nanoparticles are immobilized on a substrate, and the metal nanoparticles are bound to graphene oxide.

In an exemplary embodiment, the substrate is a surface treated glass substrate.

In an exemplary embodiment, the metal is at least one selected from Au, Ag, Pt, Pd or Cu.

In an exemplary embodiment, the local surface plasmon resonance (LSPR) sensor is used to detect aromatic volatile organic compounds.

In embodiments of the present invention, in another aspect, there is provided a method of manufacturing a local surface plasmon resonance (LSPR) sensor comprising bonding and functionalizing graphene oxide to metal nanoparticles.

In an exemplary embodiment, the method comprises: immobilizing metal nanoparticles on a substrate; And bonding graphene oxide onto the immobilized metal nanoparticles.

In an exemplary embodiment, the method comprises: synthesizing positively charged metal nanoparticles; And synthesizing a graphene oxide having a negative charge.

In an exemplary embodiment, the method comprises: synthesizing positively charged metal nanoparticles of 10-100 nm in size; Synthesizing a graphene oxide having a size of 200 nm or less with a negative charge; Immobilizing the synthesized metal nanoparticles on the surface-treated glass substrate; And bonding the graphene oxide to the metal nanoparticles immobilized on the organic substrate.

In an embodiment of the present invention, in another aspect, there is provided an apparatus for detecting aromatic volatile organic compounds, comprising: a local surface plasmon resonance (LSPR) sensor;

In an exemplary embodiment, the metal nanoparticles functionalized with graphene oxide may be pi-pi stacked with an aromatic volatile organic compound.

In another embodiment of the present invention, there is provided a method for producing an aromatic volatile organic compound detection apparatus comprising the above-described method of manufacturing a local surface plasmon resonance (LSPR) sensor do.

In embodiments of the present invention, in another aspect, there is provided a method for detecting aromatic volatile organic compounds using the local surface plasmon resonance (LSPR) sensor.

In an exemplary embodiment, the detection method detects an aromatic volatile organic compound through measurement of a Rayleigh scattering signal change of a plasmonic droplet functionalized with graphene oxide.

In an exemplary embodiment, the method comprises exposing an aromatic volatile organic compound to be detected to a surface of a plasmonic droplet functionalized with graphene oxide; Measuring a Rayleigh scattering signal of the plasmonic droplet before and after exposure of the aromatic volatile organic compound; And detecting the aromatic volatile organic compound through the wavelength change of the Rayleigh scattering spectrum in the measured signal.

In an exemplary embodiment, the detection method measures the Rayleigh scattering signal of the plasmonic droplet using a dark-field microscope both before and after exposure of the aromatic volatile organic compound.

In embodiments of the present invention, functionalization of the metal nanoparticles as plasmonic probes with graphene oxide can greatly enhance the binding force between the aromatic volatile organic compound having a low affinity and the metal nanoparticle probe. In addition, it is possible to sensitively detect aromatic volatile organic compounds by observing changes in LSPR characteristics of a single plasmonic turbidimetric system. Further, by simplifying the substrate manufacturing process and significantly reducing the volume of the analyte used in the analysis, it is possible to provide a system that can easily analyze a small amount of actual sample. This makes it possible to effectively detect harmful aromatic volatile organic compounds present in the surroundings.

Plasmonic precipitates functionalized with graphene oxide according to embodiments of the present invention are utilized for the detection of chemical, biological, and environmental contaminants in molecular units, utilizing the electrical, optical properties, and biocompatibility of graphene oxides Can be applied in various ways throughout the biosensor field.

1 is a schematic diagram illustrating the concept of an LSPR sensor system for the detection of aromatic volatile organic compounds according to exemplary embodiments of the present invention.
2 is a scanning electron microscope (TEM) photograph of gold nanoparticles used as a plasmonic probe used in an embodiment of the present invention.
Figure 3 is a scanning electron microscope (TEM) photograph (Figure 3a) and Raman signal of the graphene oxide used in an embodiment of the present invention (Figure 3b).
Fig. 4 shows the zeta potential results of the metal nanoparticles (GNP) and the graphene oxide (GO) used in the embodiment of the present invention.
FIG. 5 is a graph showing a variation of a Rayleigh scattering signal of a single plasmonic sample in the comparative example and the example of the present invention. FIG. 5 (a) is a graph showing the change of the Rayleigh- And FIG. 5B shows the results of measurement after exposing toluene to the plasmonic test piece (example) functionalized with graphene oxide.
Figure 6 is an average value of the Rayleigh-scattering signal changes after the toluene treatment of the five individual plasmonic turbidites in the comparative examples and the examples of the present invention.

Hereinafter, embodiments of the present invention will be described in detail.

Functionalization in this specification means that graphene oxide binds to the surface of metal nanoparticles used as a plasmonic probe.

Embodiments of the present invention, in one aspect, provide a local surface plasmon resonance (LSPR) sensor comprising a plasmonic probe functionalized by binding graphene oxide to metal nanoparticles.

The affinity (cohesion) between a low affinity aromatic volatile organic compound and a metal nanoparticle probe can be greatly increased through the functionalization of metal nanoparticles, which are plasmonic probes of a local surface plasmon resonance (LSPR) sensor, with graphene oxide . Accordingly, the sensitivity and reproducibility of the signal can be greatly improved.

1 is a schematic diagram illustrating the concept of an LSPR sensor system for the detection of aromatic volatile organic compounds according to exemplary embodiments of the present invention.

After a metal nanoparticle (a plasmonic tampon) with a positive charge is fixed on a substrate, for example, a surface-treated glass substrate, a negative charge of graphene oxide is bonded to the surface of the tamping body by electrostatic interaction To form a plasmonic turbine functionalized with graphene oxide.

In the case of metal nanoparticles whose surface is functionalized with graphene oxide, the plasmonic tamping material whose surface is not functionalized with graphene oxide has a weak affinity with an aromatic volatile organic compound, whereas in the case of metal nanoparticles functionalized with graphene oxide, (Pi-pi stacking) can be performed, and it can be confirmed that the binding force between the aromatic organic compound and the probe is increased. In addition, the change in the Rayleigh scattering signal of the plasmonic droplet functionalized with graphene oxide is greater than the Rayleigh scattering change of the plasmonic droplet not functionalized with graphene oxide.

In an exemplary embodiment, the metal nanoparticle size is not limited, but is 10-100 nm, preferably 20-80 nm. In the case of less than 10 nm, it is difficult to measure with an optical microscope, which is an optical measuring instrument. In this respect, the thickness is preferably 10 nm or more, more preferably 20 nm or more. On the other hand, LSPR phenomenon can occur in metal nanoparticles of 100 nm or less. Further, since the size of 80 nm or less is easy to measure in a dark field microscope, it is preferably 80 nm or less.

The size of the graphene oxide is 200 nm or less, and the size suitable for use is, for example, 20 nm or more and 200 nm or less.

The metal is not particularly limited, but may be at least one selected from Au, Ag, Pt, Pd or Cu, and may be Au in particular.

In embodiments of the present invention, in another aspect, there is provided a method of manufacturing a local surface plasmon resonance (LSPR) sensor comprising bonding and functionalizing graphene oxide to metal nanoparticles.

In an exemplary embodiment, the method comprises the steps of synthesizing metal nanoparticles having a positive charge of, for example, 10-100 nm in size, preferably 20-80 nm, synthesizing graphene oxides of sub- , Immobilization of the metal nanoparticles synthesized on the substrate, for example, the surface-treated glass substrate, and functionalization of graphene oxide by bonding the metal nanoparticles immobilized on the substrate to each other.

In embodiments of the present invention, in another aspect, there is provided an aromatic volatile organic compound detection device comprising the local surface plasmon resonance (LSPR) sensor.

The apparatus for detecting an aromatic volatile organic compound detects the aromatic volatile organic compound by exposing the local surface plasmon resonance (LSPR) sensor to an aromatic volatile organic compound.

In embodiments of the present invention, in another aspect, there is provided a method for detecting aromatic volatile organic compounds using the local surface plasmon resonance (LSPR) sensor.

In an exemplary embodiment, the detection method can detect an aromatic volatile organic compound through measurement of a Rayleigh scattering signal change of a plasmonic droplet functionalized with graphene oxide.

In other words, the scattering property of the plasmonic tamping material, that is, the incident light of the metal nanoparticles, is largely influenced by the refractive index change of the surrounding material existing on the surface of the metal nanoparticles. In the embodiments of the present invention, the refractive index of the metal nanoparticles changes due to binding of the aromatic organic compound, which is a detection substance, to the plasmonic sample functionalized with the graphene oxide, and the change of the Rayleigh scattering signal is measured Aromatic organic compounds can be detected.

In an exemplary embodiment, the detection method comprises the steps of exposing an aromatic volatile organic compound to be detected to the surface of a plasmonic droplet functionalized with graphene oxide, before and after exposure of the aromatic volatile organic compound, for example, using a dark field microscope Measuring a Rayleigh scattering signal of the plasmonic droplet, and detecting the aromatic volatile organic compound through a wavelength change of the Rayleigh scattering spectrum in the measured signal.

As described above, in the embodiments of the present invention, the aromatic volatile organic compounds can be detected with high sensitivity by measuring the Rayleigh scattering signal of a single plasmonic probe using, for example, a dark field microscope.

Also, in embodiments of the present invention, it is possible to provide a simple substrate fabrication and analysis process by using a method of sequentially adding a material to a substrate without separately preparing a plurality of substrates. Further, by analyzing at the unit particle level, the volume of the sample used in the analysis is significantly reduced, so that a small amount of actual sample can be simply analyzed.

Hereinafter, the present invention will be described in more detail by way of Examples and Experiments, but the present invention is not limited to the following description.

[Example]

≪ Preparation of gold nanoparticles having positive charge >

12.5 ml of a 60 nm spherical gold nanoparticle solution was uniformly stirred in 37.5 ml of distilled water. Next, 0.281 ml of a NH ₃ OH-H ₂ O solution having a concentration of 0.2 M was injected into the mixed solution. Then, 0.5 ml of HAuCl ₄ · 3H ₂ O having a concentration of 1% was slowly added dropwise slowly to the mixed solution and reacted for 10 minutes.

2 is a scanning electron microscope (TEM) photograph of gold nanoparticles used as a plasmonic probe used in an embodiment of the present invention. As can be seen in FIG. 2, the average size of the gold nanoparticles is 80 nm (60 nm spherical gold nanoparticles grow to 80 nm).

≪ Preparation of graphene oxide having negative charge >

0.05 g of graphite oxide was added to 50 ml of sulfuric acid, and the mixture was stirred to be uniformly mixed. Next, 0.15 g of potassium permanganate (KMnO ₄ ) was further added. After stirring for 3 hours, stirring was stopped. The temperature of the above process was all 45 ° C.

After stopping the stirring, the mixed solution was transferred to a double reactor, and 100 ml of aqueous hydrogen peroxide (H ₂ O ₂ ) was slowly injected for 20 minutes using a syringe. Hydrogen peroxide water was injected and stirred uniformly for 1 hour.

The temperature of the process was 5 < 0 > C. Stirring was stopped and additional sonication was performed for 1 hour.

Ultrasonic treatment was followed by centrifugation and washing, followed by dispersion in distilled water. In addition, graphene oxide dispersed in distilled water was passed through a 200 nm syringe filter. Through this process, the graphene oxide can be reduced to 200 nm or less.

Figure 3 is a scanning electron microscope (TEM) photograph (Figure 3a) and Raman signal of the graphene oxide used in an embodiment of the present invention (Figure 3b). The size of the graphene oxide is 200 nm or less on average. It can be confirmed that graphene oxide is present through the D and G bands shown in the Raman signal.

FIG. 4 is a graph showing the zeta potential of the gold nanoparticles (GNP) and the graphene oxide (GO) used in the embodiment of the present invention. It can be seen that the metal nanoparticles used in the plasmonic probe exhibit positive charge and the graphen oxide exhibits negative charge.

≪ Preparation of plasmonic turbidimetric functionalized with graphene oxide and detection of aromatic volatile organic compounds >

Before immersing gold nanoparticles in a glass slide, immerse the glass substrate in a solution of MPTMS [(3-mercaptopropyl) trimethoxysilane] at a concentration of 5% by volume. A glass slide with a treatment time of 2 hours was taken out, rinsed with ethanol and dried with nitrogen gas. Next, to immobilize the gold nanoparticles, 200 μl of a spherical gold nanoparticle solution having a positively charged 80 nm size was dropped on a surface-modified glass slide, and the solution was treated for 30 seconds. Then, the remaining gold nanoparticles The solution was removed.

The Rayleigh-scattering spectrum of spherical gold nanoparticles having a size of 80 nm immobilized on a modified glass substrate was measured using a dark-field microscope.

On the same glass slide, 200 μl of a graphene oxide solution having a size of 200 nm or less with a negative charge at a position where gold nanoparticles were immobilized was dropped. After the treatment for 30 minutes, the remaining graphene oxide solution was cleanly removed using distilled water, and then the Rayleigh scattering spectrum of gold nanoparticles functionalized with graphene oxide immobilized on the glass slide was measured using a dark-field microscope .

The same glass substrate was treated with a toluene solution having a concentration of 1 mM, then cleaned and dried. Next, the Rayleigh-scattering spectrum of gold nanoparticles functionalized with toluene-bound graphene oxide was measured using a dark-field microscope. All measured spectra were processed through a normalization process.

[Comparative Example]

In the same manner as in the above example, gold nanoparticles were prepared on an organic substrate, but were not functionalized with a negatively charged graphene oxide.

A toluene solution having a concentration of 1 mM was treated on a glass substrate fixed with gold nanoparticles not functionalized with graphene oxide, and then washed and dried. The Rayleigh-scattering spectrum of gold nanoparticles that were not functionalized with graphene oxide was measured using a dark-field microscope. All measured spectra were processed through a normalization process.

5 is a representative graph showing the change of the Rayleigh scattering signal of a single plasmonic probe in the comparative example and the example of the present invention.

5A is a graph showing the results of measurement of each step after exposure (1 hr, 24 hr) of toluene to a plasmonic turbidimetric function (comparative example: GNP) not functionalized with graphene oxide, and FIG. (1 hr, 24 hr) in toluene (Example: GNP / GO). For reference, the GNP indicated in red in FIG. 5A means the GNP left in the same time as the time for processing the GO in the GNP in FIG. 5B.

In comparison with the comparative example of FIG. 5A, the Rayleigh-scattering signal of the plasmonic turbid body is clearly changed in the embodiment of FIG. 5b.

As described above, the average change of the Rayleigh scattering signal enables to confirm the Rayleigh scattering signal change (red) of the plasmonic droplet functionalized with graphene oxide, thereby detecting the aromatic organic compound (toluene in this embodiment) Can be done.

Figure 6 is an average value of the Rayleigh-scattering signal changes after the toluene treatment of the five individual plasmonic turbidites in the comparative examples and the examples of the present invention.

In FIG. 6, black is a variation of the Rayleigh scattering signal of the plasmonic turbidimetry (Bare GNP) not functioning as a comparative example of graphene oxide and red is the plasmonic turbidity (GNP / GO) of the embodiment functionalized with graphene oxide ). ≪ / RTI > The concentration of toluene is 1 mM and the treatment time is 1 hour and 24 hours. In FIG. 6, it can be seen that the Rayleigh scattering signal of the plasmonic turbid body is significantly changed in the embodiment unlike the comparative example.

Claims (18)

1. An aromatic volatile organic compound detection device comprising a local surface plasmon resonance (LSPR) sensor,
The local surface plasmon resonance (LSPR) sensor includes a plasmonic tampon which is functionalized by binding of a negatively charged graphene oxide to a metal nanoparticle having a positively charged ligand,
Wherein the metal nanoparticles functionalized with graphene oxide are pi-pi stacked with the aromatic volatile organic compound. delete The method according to claim 1,
Wherein the metal nanoparticle size is 10-100 nm and the graphene oxide size is 200 nm or less. The method according to claim 1,
Wherein the local surface plasmon resonance (LSPR) sensor comprises metal nanoparticles immobilized on a substrate. 5. The method of claim 4,
Wherein the substrate is a surface-treated glass substrate. The method according to claim 1,
Wherein the metal is at least one selected from the group consisting of Au, Ag, Pt, Pd, and Cu. delete A method for producing an aromatic volatile organic compound detection apparatus,
And binding and functionalizing a graphene oxide having a negative charge on the surface of the metal nanoparticle in which a positively charged ligand is present,
Wherein the metal nanoparticles functionalized with graphene oxide are pi-pi stacked with aromatic volatile organic compounds. ≪ RTI ID = 0.0 > 15. < / RTI > 9. The method of claim 8,
The method comprises: immobilizing metal nanoparticles on a substrate; And bonding the graphene oxide to the metal nanoparticles immobilized on the substrate. ≪ RTI ID = 0.0 > 21. < / RTI > 10. The method of claim 9,
The method comprises: synthesizing positive metal nanoparticles; And synthesizing a graphen oxide having a negative charge on the surface of the substrate. 11. The method of claim 10,
The method comprises: synthesizing metal nanoparticles of 10-100 nm in size that are positively charged; Synthesizing a graphene oxide having a size of 200 nm or less with a negative charge; Immobilizing the synthesized metal nanoparticles on the surface-treated glass substrate; And bonding graphene oxide to the metal nanoparticles immobilized on the organic substrate. ≪ RTI ID = 0.0 > 21. < / RTI > delete delete delete A method for detecting an aromatic volatile organic compound,
A method for detecting an aromatic volatile organic compound, which comprises detecting an aromatic volatile organic compound using the apparatus for detecting an aromatic volatile organic compound according to any one of claims 1 to 6. 16. The method of claim 15,
Wherein the detection method detects an aromatic volatile organic compound by measuring a change in a Rayleigh scattering signal of a plasmonic turbidimetric functioned with graphene oxide. 17. The method of claim 16,
The detection method comprises: exposing an aromatic volatile organic compound to be detected to a surface of a plasmonic tamping material functionalized with graphene oxide; Measuring a Rayleigh scattering signal of the plasmonic droplet before and after exposure of the aromatic volatile organic compound; And detecting the aromatic volatile organic compound through the wavelength change of the Rayleigh-scattering spectrum. 18. The method of claim 17,
Wherein the detection method comprises measuring a Rayleigh scattering signal of a plasmonic turbidimetry using a dark field microscope before and after exposure of the aromatic volatile organic compound.

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