KR102011038B1 - Gas sensor and method for fabricating the same - Google Patents

Abstract

The present invention relates to a gas sensor including at least one gas sensing region on a substrate and a method of manufacturing the same, wherein the gas sensing region comprises gold nanoparticles and carbon nanotubes surface-treated with a peptide. According to the present invention, by using gold nanoparticles and carbon nanotubes surface-treated with a peptide that specifically binds to a specific target gas as a sensing material, it is possible to provide a highly sensitive gas sensor capable of selectively detecting only the target gas. have.

Description

Gas sensor and manufacturing method {Gas sensor and method for fabricating the same}

The present invention relates to a gas sensor and a method for manufacturing the same, and more particularly, gold nanoparticles and carbon nanotubes surface-treated with a peptide in a gas sensing region. It relates to a gas sensor that specifically reacts to a specific target gas by including and a method of manufacturing the same.

Since the gas detection characteristics using metal oxide sensing materials have been revealed, the development of sensors for detecting specific gases using various metal oxide materials and structures has been actively conducted. A lot of researches have been conducted due to the advantage that a sensor can be easily manufactured because a simple gas in which the specific gas in the atmosphere is adsorbed on the surface changes the electrical resistance or conductivity of the metal oxide.

Specific applications include detecting minute hazardous environmental gases exposed to the atmosphere and providing information about dangerous gas leaks in the surroundings. Representatively, such harmful environmental gases include NO, NO ₂ , SO ₂ , CO, CO ₂ , and volatile organic compounds (VOCs). Here, the term "VOCs" refers to hydrocarbon compounds which volatilize to the atmosphere to generate odors and ozone, and are carcinogens that cause disorders in the nervous system through skin contact or respiratory inhalation. The VOCs are collectively referred to as benzene, formaldehyde, toluene, xylene, ethylene, styrene, acetaldehyde and the like. These VOCs usually cause odors at low concentrations, are directly harmful to the environment and the human body as the compounds themselves, and participate in photochemical reactions in the atmosphere to generate secondary pollutants such as photochemical oxides.

As a conventional technology for a gas sensor for detecting such a harmful gas, Patent Document 1 (Korean Patent Publication No. 10-2011-0123559) is a substrate, a first electrode and a second electrode disposed spaced apart from each other on the substrate; And a gas sensing unit in which carbon nanotube powder is coated between the first electrode and the second electrode so that the first electrode and the second electrode are connected to each other. According to Patent Document 1, it is possible to provide a carbon nanotube gas sensor that not only improves the selectivity with respect to the detection gas but also improves the reaction and recovery rate, and as the detection gas, an oxidizing gas, a reducing gas, and volatile organic compounds (VOCs). Presenting.

However, substantially, the gas sensor according to Patent Document 1 reacted sensitively to NO ₂ and SO ₂ gases, but still exhibited low selectivity and sensitivity to other gases except these, such as VOCs. In addition, since the gas sensor does not specifically react to a specific target gas, it is difficult to clearly determine whether the target gas exists only by changing the electrical resistance or the electrical conductivity of the gas sensor.

KR 1020110123559 A

The problem to be solved by the present invention is a gas having excellent selectivity and sensitivity to the gas to be detected by including gold nanoparticles and carbon nanotubes surface-treated with a peptide specifically binding to a specific target gas in the gas detection region It is to provide a sensor and a method of manufacturing the same.

In order to solve the above problems, the present invention provides a gas sensor comprising at least one gas sensing region on the substrate, the gas sensing region comprises gold nanoparticles and carbon nanotubes surface-treated with a peptide do.

The peptide is characterized in that the thiol (thiol) as an intermediate medium is bound to the surface of the gold nanoparticles, the peptide is X ₂ SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 1), X ₂ X ₂ PX ₃ At least one selected from the group consisting of X ₂ AX ₃ P (SEQ ID NO: 2), SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 3), and X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 4) It may include. However, in the peptide, X ₁ may be W, Y, F or H, X ₂ may be D, E, N or Q, and X ₃ may be I, L or V.

The carbon nanotubes may include single-walled carbon nanotubes (SWCNTs).

It is preferable that the average diameter of the said gold nanoparticles is 2-20 nm.

On the other hand, the present invention provides a method of manufacturing a gas sensor, the manufacturing method comprises the steps of (a) adsorbing carbon nanotubes on a substrate; (b) forming gold nanoparticles on the surface of the carbon nanotubes; (c) forming an electrode on the substrate subjected to step (b); And (d) surface treating the gold nanoparticles with the peptide by incubating the substrate on which the electrode is formed by immersion in a peptide solution.

Step (b) comprises the steps of vacuum depositing a gold (Au) thin film on a substrate on which carbon nanotubes are adsorbed according to step (a); And heat treating the substrate on which the gold (Au) thin film is vacuum deposited to form gold (Au) nanoparticles on the substrate on which the carbon nanotubes are adsorbed.

The peptide solution may be prepared by adding the peptide to any one or two or more solvents selected from the group consisting of distilled water, Phosphate-Buffered Saline (PBS) and Tri-Buffered Saline (TBS). In the peptide solution, the pH of the solvent is preferably 6-8.

The peptides are X ₂ SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 1), X ₂ X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 2), SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 3) and X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 4) may comprise one or more selected from the group consisting of. However, in the peptide, X ₁ may be W, Y, F or H, X ₂ may be D, E, N or Q, and X ₃ may be I, L or V.

By the surface treatment in step (d), the peptide may be bound to the surface of the gold nanoparticle by using a thiol group as an intermediate.

According to the present invention, by using gold nanoparticles and carbon nanotubes surface-treated with a peptide that specifically binds to a specific target gas as a sensing material, it is possible to provide a highly sensitive gas sensor capable of selectively detecting only the target gas. have.

In addition, the gas sensor according to the present invention is capable of operating at room temperature without a heater, thereby minimizing power consumption, and miniaturization can be used as a portable device.

1 schematically shows an example of phage with peptides displayed.
FIG. 2 schematically illustrates a state in which a sensing material included in a gas sensing region of a gas sensor is coupled with a target gas according to an exemplary embodiment of the present invention.
Figure 3 schematically shows a manufacturing process of the gas sensor according to an embodiment of the present invention.
4 is a scanning electron microscope (SEM) photograph of a substrate subjected to a heat treatment according to the manufacturing process of FIG. 3.
FIG. 5 is a transmission electron microscopy (TEM) photograph of a substrate subjected to a heat treatment according to the manufacturing process of FIG. 3.
FIG. 6 is a graph showing comparison of sensitivity according to gas concentration measured by each gas sensor when toluene gas is applied to the gas sensors manufactured according to Examples and Comparative Examples 1 to 3. FIG.
7 is a graph illustrating a comparison of sensitivity according to the concentration of each gas when toluene, benzene and xylene gas are applied to the gas sensor manufactured according to the embodiment.

The present invention relates to a gas sensor including at least one gas sensing region on a substrate and a method of manufacturing the same, wherein the gas sensing region comprises gold nanoparticles and carbon nanotubes surface-treated with a peptide.

First, the gas sensor according to the present invention will be described.

Specifically, the gas sensor according to an embodiment of the present invention; A gas sensing region formed on at least a portion of the substrate and including gold nanoparticles and carbon nanotubes surface-treated with a peptide; And a first electrode and a second electrode electrically connected to the gas sensing region and spaced apart from each other.

As the material used for the substrate, III-V compound semiconductors such as Si, GaAs, InP, InGaAs, glass, polymers, oxide thin films, dielectric thin films, metal thin films, and the like may be used, but are not limited thereto. Preferably, the substrate may include a silicon substrate, and more preferably may include a silicon substrate having an insulating film formed on a surface thereof.

In the present invention, gold nanoparticles (Au NP) and carbon nanotubes (CNT) surface-treated with the peptide are included in the gas sensing region and used as a sensing material.

In general, carbon nanotubes (CNTs) are known to have 1000 times the current density of copper wire and 10 times the carrier mobility of silicon. For this reason, it is widely used as a material of a high sensitivity / high speed electronic element. In addition, a highly sensitive chemical / biosensor may be manufactured by using a change in electrical conductivity due to the interaction between the sensing material and the carbon nanotubes. In addition, carbon nanotubes can be operated at room temperature, as well as nano-sized material can significantly reduce the size of the sensor can be applied to portable sensors.

Carbon nanotubes used in the sensing material of the present invention may include any one or two or more selected from the group consisting of single-walled carbon nanotubes, double-walled carbon nanotubes and multi-walled carbon nanotubes, preferably single-walled carbon nano It may include a tube (SWCNT, single-walled carbon nanotube). This is because single-walled carbon nanotubes exhibit superior performance in terms of sensitivity and reaction speed than multi-walled carbon nanotubes.

In addition, the present invention provides a gas sensor having a very high selectivity to the target gas by using the gold nanoparticles surface-treated with a peptide that specifically binds to a specific target gas with the carbon nanotubes as a sensing material as a sensing material. can do. In the present invention, preferably, the peptide may be composed of a structure in which 7 or 8 amino acids are connected, and a functional group, such as a thiol group (-SH), that can be directly bonded to gold nanoparticles may be bound to one end of the peptide.

Preferably, "gold nanoparticles surface-treated with a peptide" herein refers to the peptide is directly bonded to the surface of the gold nanoparticles with a thiol group as an intermediate medium. By the binding, a strong binding force can be formed between the gold nanoparticles and the peptide, and as a result, it is possible to provide a highly reactive gas sensor. If the peptide is directly treated on the surface of the carbon nanotubes without gold nanoparticles, the peptide and the carbon nanotubes are bonded by general van der Walls force. Since van der Waals bonds are much weaker than the thiol-based peptide and gold (Au) bonds, the efficiency of the peptides being directly bonded to the carbon nanotube surface is very low. Therefore, in the case of a gas sensor including gold nanoparticles (Au NP, Au nanoparticles) and carbon nanotubes (CNT, carbon nanotube) surface-treated with a peptide according to the present invention, carbon nanotubes surface-treated with a peptide It can have much higher reactivity compared to gas sensor using.

That is, the gold nanoparticles firmly bind to a peptide that specifically binds to a specific target gas, thereby providing a reliable gas sensor, and at the same time, carbon nanotubes serve as a catalyst in detecting gas. . In order to play this role, the smaller the average particle diameter of the gold nanoparticles and the more the individual particles are present in the separated form is preferable. The average particle diameter of the gold nanoparticles may be several nm to several tens nm, preferably 2 to 20 nm. If the average particle diameter of the gold nanoparticles falls within the above range, the change in electrical resistance due to the gas in contact can be checked more sensitively, which is preferable.

The peptide used in the present invention can be used without limitation so long as it specifically binds to a specific target gas. The peptide can be synthesized or purchased. For example, as the synthesis method, a peptide that selectively reacts only with a specific gas among peptides displayed on phage can be screened to find an amino acid sequence, and then a method of replicating the peptide having the amino acid sequence can be used. In addition, a method of synthesizing a peptide having an amino acid sequence found by the above screening by requesting a peptide replication company can be used. In the synthesis or replication process, a process of binding a thiol group (-SH) which does not react with a specific gas to the peptide terminal may be added, and the peptide obtained through this process may be directly bonded with gold nanoparticles through a thiol group. have. Here, "phage" is a term used interchangeably with "bacteriophage" and means a virus that infects bacteria and replicates within bacteria. 1 schematically shows an example of phage with peptides displayed.

Preferably, the peptide is X ₂ SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 1), X ₂ X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 2), SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 3) And X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 4), and at least one selected from the group consisting of X ₁ is W, Y, F or H in the peptide, and X ₂ is D, E, N or Q and X ₃ may be I, L or V.

Specifically, the peptide comprising the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 3 may selectively bind to benzene in the VOCs, the peptide comprising the amino acid sequence of SEQ ID NO: 2 or SEQ ID NO: 4 to toluene in the VOCs May optionally be combined. In particular, toluene may cause abnormalities in the central nervous system and respiratory organs, may cause headaches, and death may be caused by prolonged exposure to toluene. Therefore, there is a great need for a gas sensor capable of detecting toluene. high. In addition, the toluene is a representative biomarker included in the exhalation gas is an indicator of lung cancer. Therefore, a gas sensor that detects toluene with high sensitivity can be utilized as an exhalation diagnostic sensor that detects gas emitted from the mouth through the human lung.

In addition, as long as it can specifically bind to a specific gas in the sensing region of the gas sensor according to the present invention, peptides having various amino acid sequences can be used in a state of being surface-treated with gold nanoparticles.

On the other hand, the left side of FIG. 2 schematically shows a state in which the sensing material included in the gas sensor according to an embodiment of the present invention is coupled with the target gas, and on the right side, when the target gas reacts with the sensing material. A graph showing resistance change over time is shown. According to the present invention, it is possible to provide a gas sensor for selectively detecting the target gas by using gold nanoparticles surface-treated with a peptide that specifically binds to a specific target gas together with carbon nanotubes as a sensing material. . Therefore, the gas sensor can selectively detect only a target gas to be detected even under an environment in which various gases coexist, for example, when applied to an exhalation sensor, it can detect a specific gas corresponding to a biomarker to diagnose a disease. have.

According to the present invention, the first electrode and the second electrode electrically connected to the gas sensing region and spaced apart from each other on the substrate may be a source electrode and a drain electrode. The material of the electrode is gold (Au), silver (Ag), chromium (Cr), tantalum (Ta), titanium (Ti), copper (Cu), aluminum (Al), molybdenum (Mo), tungsten (W), It may include at least one metal of nickel (Ni), palladium (Pd), and platinum (Pt).

The method of manufacturing the gas sensor includes (a) adsorbing carbon nanotubes on a substrate, (b) forming gold nanoparticles on the surface of the carbon nanotubes, and (c) substrates that have undergone the step (b). Forming an electrode on the surface, and (d) surface treating the gold nanoparticles with the peptide by incubating the substrate on which the electrode is formed by immersion in a peptide solution.

Hereinafter, an embodiment of a method of manufacturing a gas sensor will be described in detail with reference to FIG. 3.

(a) On a substrate  Adsorbing carbon nanotubes

First, a substrate is prepared, and carbon nanotubes are adsorbed onto the substrate. The carbon nanotubes preferably include single-walled carbon nanotubes as described above. As a method of adsorbing carbon nanotubes, a dipping method in which a substrate is immersed in a solution in which carbon nanotubes are dispersed and then removed, or a drop casting method in which a solution in which carbon nanotubes are dispersed on a desired substrate is dropped. Alternatively, a spray method of spraying a solution in which carbon nanotubes are dispersed may be used. In order to uniformly disperse the carbon nanotubes, the spray method may be preferable, and the spray process may be performed under an argon (Ar) atmosphere to prevent oxidation of oxygen and carbon nanotubes. The case of using the spray method is shown in FIG.

The carbon nanotube dispersed solution is dichlorobenzene (dichlorobenzene), ortho-dichlorobenzene (ortho-dichlorobenzene), N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidinone), hexamethyl phosphoamide ( 1 selected from the group consisting of hexamethylphosphoramide, monochlorobenzene, N, N-dimethylformamide, dichloroethane, isopropyl alcohol, ethanol, chloroform and toluene It may include more than one solvent. In addition, by irradiating the solution with ultrasonic waves, the carbon nanotubes may be evenly dispersed in the solution.

The concentration of carbon nanotubes in the solution in which the carbon nanotubes are dispersed may be 0.01 to 0.50 mg / ml. If the concentration is lower than 0.01 mg / ml, the amount of carbon nanotubes adsorbed is too small to function properly as a sensor. If the concentration is higher than 0.50 mg / ml, it takes a long time to disperse the carbon nanotubes. Desensitization of the and the carbon nanotubes are consumed more than necessary may cause a rise in manufacturing costs.

(b) forming gold nanoparticles

This step is a step of forming gold nanoparticles (Au nanoparticles (Au NP) on the surface of the carbon nanotubes adsorbed on the substrate according to step (a). As a method of forming the gold (Au) nanoparticles, conventional methods may be used without limitation. For example, a method of manufacturing nanoparticles by heat treatment after thin film deposition, a method of synthesizing nanoparticles by a wet chemical method, a method of synthesizing nanoparticles by UV irradiation, or a method of forming nanoparticles by microwave irradiation may be used. Preferably, a method of heat treatment after deposition of the nano thin film may be used.

For example, the method of heat-treating the nano-film after deposition, the vacuum (Au) thin film deposited on the carbon nanotube adsorbed substrate according to the step (a) and the gold (Au) thin film is vacuum deposited Heat-treating the substrate to form gold (Au) nanoparticles on the substrate to which the carbon nanotubes are adsorbed.

As a method of depositing the gold (Au) thin film, conventional vacuum deposition may be used without limitation. For example, a method of thermal evaporation, electron beam evaporation, sputtering, or the like may be used, and sputtering may be preferably used. For example, the sputtering may be performed under an argon atmosphere to prevent oxidation of oxygen and carbon nanotubes, and the thickness of the Au thin film deposited by the sputtering may be 0.1 nm to 5 nm. If the thickness of the (Au) thin film is in the above range, it is preferable that the gold (Au) thin film deposited on the substrate by heat treatment afterwards becomes nanoparticles.

In addition, the heat treatment is performed to nanoparticle the gold (Au) thin film deposited on the substrate, and may be performed in an argon atmosphere to prevent oxidation of carbon nanotubes. The heat treatment may be carried out in a temperature range of 500 ~ 800 ℃. When the heat treatment temperature is included in the above range, it is preferable to form gold (Au) nanoparticles without loss due to the high temperature of the carbon nanotubes.

The average diameter of the gold (Au) nanoparticles formed on the substrate on which the carbon nanotubes are adsorbed by the heat treatment may be several to several tens of nm, and preferably 2 to 20 nm.

(c) forming an electrode

This step is to form an electrode on the substrate subjected to the step (b). The electrode may be a source electrode and a drain electrode, and may be formed according to a conventional photolithography process. For example, a metal or metal oxide thin film is formed on the substrate having undergone the steps (a) to (b). Then, an exposure process is performed on the metal or metal oxide thin film to expose regions (or regions other than the source and drain electrodes) on which the source and drain electrodes are to be formed. Subsequently, etching is performed according to a conventional etching method, and finally, photoresist is removed with a photoresist stripper to form source and drain electrodes of metals and metal oxides.

(d) surface treating the gold nanoparticles with a peptide

This step is a step of surface treatment of the gold nanoparticles with the peptide by incubation (immersion) by immersing the substrate on which the electrode is formed in the peptide solution according to step (c).

The peptide is X ₂ SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 1), X ₂ X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 2), SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 3) as described above. ) And X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 4) may comprise one or more selected from the group consisting of, wherein X ₁ in the peptide is W, Y, F or H, X ₂ Is D, E, N or Q, and X ₃ may be I, L or V.

In addition, the peptide solution may be prepared by adding the peptide to any one or two or more solvents selected from the group consisting of distilled water, Phosphate-Buffered Saline (PBS) and Tri-Buffered Saline (TBS). At this time, the pH of the solvent is preferably 6 ~ 8.

After immersing the substrate subjected to the step (c) in the peptide solution prepared as described above, the gold nanoparticles are surface treated with a peptide through incubation, and the surface treatment causes the peptide to contain a thiol group. The intermediate may be directly bonded to the surface of the gold nanoparticles. Preferably, the incubation may be performed for 30 minutes to 48 hours.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example (see Figure 3)

A SiO ₂ / Si substrate (manufacturer: SILTRON INC, product name: EPI-Prime Si wafer) having a silicon oxide insulating film (SiO ₂ ) formed on a silicon substrate was prepared. At this time, the thickness of the insulating film is 300 nm.

In order to adsorb carbon nanotubes on the substrate, first, 1 mg of single-walled carbon nanotubes (SWCNT) (Nanointegris Corp.) was added to 1,2-dichlorobenzene (C ₆ H ₄ Cl ₂ , Sigma-Aldrich Corp.) was added to 50 ml, and then sonicated at room temperature for 4 hours to prepare a carbon nanotube suspension in which single-walled carbon nanotubes were uniformly dispersed. Then, 2 ml of the carbon nanotube suspension was sprayed onto the SiO ₂ / Si substrate using an air-brush-spray gun (manufacturer: Mr. hobby, model name: PS-770) equipped with a 0.18 mm nozzle. , Heated to 180 ° C. on a hot plate.

A gold thin film was deposited on a substrate on which the carbon nanotubes were adsorbed using a sputtering apparatus (manufacturer: SANYU ELECTRON COATER, model name: SC-701MKII ADVANCE). The silicon substrate on which the gold (Au) thin film was vacuum deposited was heat-treated at 500 ° C. under argon (Ar) gas. SEM and TEM images of the substrate after the heat treatment are shown in FIGS. 4 and 5, respectively.

A source electrode and a drain electrode were formed on a substrate on which the gold nanoparticles were deposited according to a conventional photolithography process. At this time, gold (Au) / titanium (Ti) was used as the source electrode and the drain electrode.

The gas sensor was prepared by binding the peptide to the surface of the gold nanoparticles by immersing the substrate on which the electrode was formed in a peptide solution and incubating for 20 hours. At this time, the peptide solution is an aqueous solution having a molar concentration of 10 μM, the peptide has an amino acid sequence of (SEQ ID NO: 5), and a thiol group is bonded to one end of the peptide. Through the incubation process, the peptide is bound to the surface of the gold nanoparticle by using a thiol group as an intermediate medium. In this process, the peptide is bound to the gold surface used as the electrode, but due to the very high charge density of the gold electrode, the ratio of the charge transferred by the reaction with the analyte gas is small.

Through the above process, a gas sensor including gold nanoparticles and carbon nanotubes surface-treated with a peptide as a sensing material (hereinafter referred to as "Au NPs-SWCNTs / Peptide") was prepared.

Comparative Example 1

After preparing a substrate on which the carbon nanotubes were adsorbed in the same manner as in Example 1, a source electrode and a drain electrode were formed on the substrate by a conventional photolithography process to manufacture a gas sensor.

Through the above process, a gas sensor containing carbon nanotubes alone as a sensing material (hereinafter referred to as "Pristine SWCNTs") was manufactured.

Comparative Example 2

After preparing the substrate on which the carbon nanotubes were adsorbed in the same manner as in Example 1, gold nanoparticles were deposited and an electrode was formed thereon to prepare a gas sensor.

Through the above process, a gas sensor including gold nanoparticles and carbon nanotubes as a sensing material (hereinafter referred to as "Au NPs-SWCNTs") was manufactured.

Comparative Example 3

After preparing a substrate on which the carbon nanotubes were adsorbed in the same manner as in Example 1, and then forming an electrode thereon, the carbon nanotubes were immersed in a peptide solution and incubated for 20 hours to incubate the carbon nanotubes. A gas sensor was prepared by binding a peptide to the tube surface. In this case, the peptide solution was prepared in the same manner as in Example 1.

Through the above process, a gas sensor including a carbon nanotube and a peptide as a sensing material (hereinafter referred to as "Pristine SWCNTs / Peptide") was manufactured.

Characterization of Gas Sensor

The gas sensors manufactured according to Examples, Comparative Examples 1, 2 and 3 were connected to a DC power supply (keithley 2400), and then, toluene, benzene, and xylene gas were connected to a mass flow controller. Using this method, the resistance change flowing through the sensor was measured at the same time as the constant DC power was applied. At this time, all measurements were performed at room temperature.

The sensitivity of the sensor for the test gases is calculated by the following equation (1), and the sensitivity for each sensor and the sensitivity for each gas are shown in FIGS. 6 and 7.

Sensitivity (%) = (ΔR / R ₀ ) × 100. (One)

In Equation (1), R ₀ represents an initial resistance value when no reaction gas is present, and ΔR represents a value obtained by subtracting R ₀ from a resistance value when there is a reaction gas.

Looking at Figure 6, it can be seen that the gas sensor manufactured according to the embodiment (Au NPs-SWCNTs / Peptide) is significantly improved sensitivity as the concentration of toluene gas increases. On the other hand, the gas sensor manufactured according to Comparative Example 1 (Pristine SWCNTs), Comparative Example 2 (Au NPs-SWCNTs) and Comparative Example 3 (Pristine SWCNTs / Peptide) not only has low sensitivity to toluene gas, but also toluene gas concentration. Even if increased, sensitivity change was insignificant.

Referring to FIG. 7, the gas sensor manufactured according to the embodiment does not detect or exhibit low sensitivity to xylene or benzene gas, and has a very high sensitivity to toluene gas, indicating that the selectivity is high only for toluene gas. Can be.

As a result, when gold nanoparticles surface-treated with a peptide having an amino acid sequence of DNPIQAVP (SEQ ID NO: 5) that specifically binds to toluene gas are used as a sensing material together with carbon nanotubes, only toluene gas can be selectively detected. It can be seen that a high sensitivity gas sensor can be manufactured.

As described above, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the protection scope of the present invention, which should be interpreted by the following claims, and all technical ideas within the equivalent scope thereof. Should be construed as being included in the scope of the present invention.

<110> Korea Institute of Science and Technology <120> Gas sensor and method for fabricating the same <130> PA17-031KI <160> 5 <170> KoPatentIn 3.0 <210> 1 <211> 8 <212> PRT <213> Artificial Sequence <220> <223> peptide selectively binding to graphitic materials and volatile          organic compounds <220> <221> VARIANT <222> (3) <223> X is W, Y, F or H <220> <221> VARIANT <222> (1) <223> X is D, E, N or Q <220> <221> VARIANT <222> (6) <223> X is D, E, N or Q <220> <221> VARIANT <222> (7) <223> X is I, L or V <400> 1 Xaa Ser Xaa Ala Ala Xaa Xaa Pro   1 5 <210> 2 <211> 8 <212> PRT <213> Artificial Sequence <220> <223> peptide selectively binding to graphitic materials and volatile          organic compounds <220> <221> VARIANT <222> (1) <223> X is D, E, N or Q <220> <221> VARIANT <222> (2) <223> X is D, E, N or Q <220> <221> VARIANT <222> (4) <223> X is I, L or V <220> <221> VARIANT <222> (5) <223> X is D, E, N or Q <220> <221> VARIANT <222> (7) <223> X is I, L or V <400> 2 Xaa Xaa Pro Xaa Xaa Ala Xaa Pro   1 5 <210> 3 <211> 7 <212> PRT <213> Artificial Sequence <220> <223> peptide selectively binding to graphitic materials and volatile          organic compounds <220> <221> VARIANT <222> (2) <223> X is W, Y, F or H <220> <221> VARIANT <222> (5) <223> X is D, E, N or Q <220> <221> VARIANT <222> (6) <223> X is I, L or V <400> 3 Ser Xaa Ala Ala Xaa Xaa Pro   1 5 <210> 4 <211> 7 <212> PRT <213> Artificial Sequence <220> <223> peptide selectively binding to graphitic materials and volatile          organic compounds <220> <221> VARIANT <222> (1) <223> X is D, E, N or Q <220> <221> VARIANT <222> (3) <223> X is I, L or V <220> <221> VARIANT <222> (4) <223> X is D, E, N or Q <220> <221> VARIANT <222> (6) <223> X is I, L or V <400> 4 Xaa Pro Xaa Xaa Ala Xaa Pro   1 5 <210> 5 <211> 8 <212> PRT <213> Artificial Sequence <220> <223> peptide selectively binding to graphitic materials and volatile          organic compounds <400> 5 Asp Asn Pro Ile Gln Ala Val Pro   1 5

Claims (11)

A gas sensor comprising at least one gas detection region on a substrate,
The gas detection region,
Carbon nanotubes adsorbed on the substrate;
Gold nanoparticles vacuum deposited on the surface of the carbon nanotubes; And
And a peptide incubated on the surface of the gold nanoparticles by immersing the substrate in which the carbon nanotubes are adsorbed and the gold nanoparticles are deposited in a peptide aqueous solution. The method of claim 1,
The peptide is a gas sensor, characterized in that bonded to the surface of the gold nanoparticles with a thiol (thiol) group as an intermediate. The method of claim 1,
The peptides are X ₂ SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 1), X ₂ X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 2), SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 3) and X ₂ Gas sensor, characterized in that it comprises at least one selected from the group consisting of the amino acid sequence of PX ₃ X ₂ AX ₃ P (SEQ ID NO: 4):
In said peptide X ₁ is W, Y, F or H, X ₂ is D, E, N or Q and X ₃ is I, L or V. The method of claim 1,
The carbon nanotube is a gas sensor, characterized in that it comprises a single-walled carbon nanotube (SWCNT). The method of claim 1,
Gas sensor, characterized in that the average diameter of the gold nanoparticles is 2 to 20 nm. (a) adsorbing carbon nanotubes on a substrate;
(b) vacuum depositing a gold (Au) thin film on the substrate on which the carbon nanotubes are adsorbed, and then performing heat treatment to form gold nanoparticles on the surface of the carbon nanotubes;
(c) forming an electrode on the substrate subjected to step (b); And
(d) a method of manufacturing a gas sensor comprising surface treating the gold nanoparticles with a peptide by incubating the substrate on which the electrode is formed in an aqueous peptide solution. delete The method of claim 6,
The peptide aqueous solution is prepared by adding the peptide to any one or two or more solvents selected from the group consisting of distilled water, Phosphate-Buffered Saline (PBS) and Tri-Buffered Saline (TBS). The method of claim 8,
PH of the solvent in the aqueous peptide solution is a method of producing a gas sensor, characterized in that 6 to 8. The method of claim 6,
The peptides are X ₂ SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 1), X ₂ X ₂ PX ₃ X ₂ AX ₃ P (SEQ ID NO: 2), SX ₁ AAX ₂ X ₃ P (SEQ ID NO: 3) and X ₂ Method for producing a gas sensor, characterized in that it comprises one or more selected from the group consisting of the amino acid sequence of PX ₃ X ₂ AX ₃ P (SEQ ID NO: 4):
In said peptide X ₁ is W, Y, F or H, X ₂ is D, E, N or Q and X ₃ is I, L or V. The method of claim 6,
In the step (d), by the surface treatment, the peptide is bound to the surface of the gold nanoparticles by using a thiol group as an intermediate medium.

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