KR20120053797A - Electrode for electrochemical biosensor and biosensor including the same - Google Patents

Abstract

PURPOSE: An electrode for an electrochemical biosensor and a bio sensor having the same are provided to effectively living things and biomaterials by selectively controlling a density, a height, a diameter, an area, a shape, an arrangement shape of a carbon nano tube. CONSTITUTION: An electrode for an electrochemical biosensor comprises a substrate(10), a first layer(20), a carbon nano tube(30), and a second layer(40). The first layer comprises a grapheme formed on the substrate. The carbon nano tube is formed on the first layer. The second layer is arranged on the upper part of the carbon nano tube and specific biomaterials are fixed on the second layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical biosensor,

The present invention relates to an electrode for an electrochemical biosensor and a biosensor including the electrode. More particularly, the present invention relates to an electrode for an electrochemical biosensor, and more particularly to a biosensor comprising a carbon nanotube An electrode for an electrochemical biosensor capable of more effectively measuring biological or biomolecules by selectively controlling the density, height, diameter, area, shape, and arrangement of the electrodes and further expanding the application fields as various sensors To a biosensor.

Generally, a biosensor is a measuring device for measuring the state or concentration of a substance, especially an organic compound, using a reaction system equipped with a biological or biological substance to be analyzed. Such a biosensor is constituted by a bio-sensing membrane and a signal transducer so that the measured information can be converted into a recognizable signal.

The mechanism of the biosensor is such that the enzyme is fixed in a film shape, the electrode is attached to the electrode, and the reaction is read by a computer. When an enzyme or the like is reacted with a chemical substance in the solution, the amount of chemical substance prepared in the biosensor changes, And the change amount is converted into an electric signal to be measured.

For example, a biosensor may be a membrane in which an enzyme, an antigen, an antigen, a hormone, or a microorganism is immobilized, and may be referred to as an enzyme sensor or a glucose sensor. In addition, such biosensors are electronic devices that are expected to have a wide range of applications such as medical, fermentation industry, food industry, agriculture, forestry and fisheries industry, and environment preservation.

The advantage of such a biosensor is that, unlike other analytical methods, the biosensor can rapidly and accurately analyze the analyte by reacting with the biological or biomaterial to be analyzed.

In particular, in the case of an electrochemical biosensor, since a separate transducer is not necessary, the operation principle of the biosensor is very simple, and the structure of the biosensor can be simplified, thereby making it possible to miniaturize and portable .

On the other hand, in an electrochemical biosensor, an electrocatalyst characteristic of an electrode that basically converts the result of a chemical reaction into an electric signal is very important for accurate and rapid analysis of a biomaterial existing in a living body in a trace amount do. Therefore, as the electrode for an electrochemical biosensor, generally, a carbon electrode such as a noble metal such as platinum or gold or a glassy carbon having a good electrocatalytic property is generally used.

However, precious metals such as platinum or gold have a disadvantage in that they are expensive, and carbon electrodes such as glass carbon have a disadvantage in that the electrocatalytic properties are poor and the background current is large. Therefore, it is essential to develop a new electrode material having a low cost and excellent electrocatalytic characteristics.

As a typical biosensor, it has been a common practice to use a disposable strip form by using a screen printing method or a gold deposition to fabricate a flat electrode system for ease of processing.

However, the general disposable strip form is disadvantageous in that it can be operated only by artificially injecting analytes such as blood or body fluids into a sample injection port, and thus its application field is very limited. That is, it has a disadvantage that it is difficult to apply to various systems capable of collecting a sample or a sample directly from a living body and simultaneously analyzing a living body in a trace amount.

Therefore, there is a need for 1) a new electrode material that can be used in a biosensor, 2) an electrode for a biosensor capable of expanding the application field as a sensor by changing the three-dimensional structure or arrangement of the electrode material .

In other words, it can be transformed into a variety of three-dimensional structures such as a bent shape and a coil shape as well as a general flat-type structure while having an electrocatalytic characteristic that is lower than that of conventional electrode materials, and is inexpensive. There is an increasing need to develop new electrodes capable of sensing various biomaterials as well as being applicable to a new type of sampling tool and an integrated sensor system.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to provide a method of forming a carbon nanotube on a graphene by vertically forming a carbon nanotube on the graphene, An electrode for an electrochemical biosensor that can be applied to a sensor integrated with a biomaterial sampling tool by being deformable into various three-dimensional structures such as a flat shape, a large-bend shape, a coil shape, etc., and a biosensor including the same will be.

It is another object of the present invention to provide a carbon nanotube composite material which can be obtained by vertically forming carbon nanotubes on graphene, 1) improving effective electrode area, 2) capable of forming a custom electrode structure of a biosensor system, and 3) And 4) an electrode for an electrochemical biosensor which is superior in terms of cost as compared with conventional noble metals (gold, silver, platinum, etc.), and a biosensor containing the same .

It is another object of the present invention to provide an electrochemical biosensor capable of controlling the detection characteristics of electrodes and controlling various bio material characteristics by controlling the density, length, shape, diameter, and arrangement shape of the carbon nanotubes to be deposited Electrode and a biosensor including the same.

Further, the object of the present invention is to provide a biosensor for a biosensor, which is capable of easily controlling the size and shape of the electrode for a biosensor, and 2) And 3) an electrode for an electrochemical biosensor capable of manufacturing a biosensor of a cylindrical shape or a coil shape of various sizes by controlling the bending rate of the bent shape, and a biosensor including the same.

An electrode for an electrochemical biosensor according to the present invention comprises a substrate; A first layer comprising a graphene formed on the substrate; Carbon nanotubes formed on the first layer; And a second layer positioned on the carbon nanotube and having a specific bio material fixed or supported thereon.

Preferably, the first layer is at least one multilayer graphene (MLG).

Preferably, the first layer is selected from the group consisting of a flexible planar, cylindrical, cylindrical, square columnar, coiled, and combinations thereof.

Preferably, the first layer is characterized by a thickness in the range of 50 to 500 mu m.

Preferably, the carbon nanotubes are formed perpendicular to the first layer.

Preferably, the carbon nanotubes are controlled in at least one of density, height, diameter, and arrangement thereof so that the detection characteristics of the electrodes are controlled.

Preferably, the biomaterial is selected from the group consisting of an antibody, an enzyme, an extramammer, a protein, a nucleic acid, a microorganism, a cell, a lipid, a hormone, DNA, PNA, RNA and a mixture thereof.

The electrochemical biosensor according to the present invention may further comprise: an electrode for an electrochemical biosensor; An auxiliary electrode; And a reference electrode, characterized in that the biomaterial can be detected by an electrochemical reaction.

According to the present invention, since the carbon nanotubes are vertically formed on the graphene to increase the effective electrode area, the electrocatalytic properties are improved. In addition, due to the characteristics of the graphene, various shapes such as a flat shape, It can be applied to a sensor integrated with a biomaterial sampling tool.

According to the present invention, 1) the effective electrode area can be improved, 2) a customized electrode structure can be formed in the biosensor system, 3) the reaction characteristics can be controlled by adjusting the carbon nanotube synthesis conditions, and 4) (Gold, silver, platinum, and the like) used in the present invention, it is very excellent in terms of cost.

Also, according to the present invention, by controlling the density, length, shape, diameter, and arrangement of carbon nanotubes to be deposited, it is possible to control the detection characteristics of the electrodes and to detect various bio material characteristics.

Further, according to the present invention, by using the flexible multi-layer graphene, 1) the size and shape of the electrode for the biosensor can be easily controlled, and 2) the electrode 3) It is possible to manufacture a biosensor of various sizes such as a cylindrical shape and a coil shape by controlling the bending rate of the bent shape.

1 (a), 1 (b) and 1 (c) schematically show an electrode for an electrochemical biosensor according to an embodiment of the present invention,
2 is a photograph showing a graphene used in the present invention through a scanning electron microscope (SEM)
FIG. 3 is a photograph showing carbon nanotubes deposited on graphene through a scanning electron microscope in the present invention,
4 is a scanning electron microscope (SEM) image of an electrode for an electrochemical biosensor according to an embodiment of the present invention in which carbon nanotubes are vertically formed on a multi-layer graphene,
FIG. 5 is a photograph showing a state in which an electrode for an electrochemical biosensor according to an embodiment of the present invention is applied to a columnar structure by a scanning electron microscope. FIG.

Hereinafter, preferred embodiments of an electrode for an electrochemical biosensor and a biosensor including the same according to the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

<Examples>

1 (a), 1 (b) and 1 (c) are schematic views of an electrode for an electrochemical biosensor according to an embodiment of the present invention. 2 is a photograph showing a graphene used in the present invention through a scanning electron microscope (SEM). FIG. 3 is a photograph showing carbon nanotubes deposited on graphene through a scanning electron microscope in the present invention. FIG.

Referring to FIG. 1, an electrode 100 for an electrochemical biosensor according to an embodiment of the present invention includes a substrate 10; A first layer (20) comprising graphene formed on the substrate (10); A carbon nanotube 30 formed on the first layer 20; And a second layer (40) located on the carbon nanotubes. The biomaterial 50 is supported or fixed in the second layer 40 in various ways.

The substrate 10 may be selected from the group consisting of glass, plastic, metal, ceramic, and silicon. However, the type of substrate Is not particularly limited as long as graphene can be deposited or formed thereon.

The first layer 20 is a layer containing graphene or of graphene itself. These graphenes have a two-dimensional planar shape and are characterized by a very thin thickness of about 0.2 nm and high physical and chemical stability. In addition, it is able to move electrons 100 times or more faster than monocrystalline silicon, which is mainly used for semiconductors. Strength is more than 200 times stronger than steel, and has twice the thermal conductivity than diamonds with the highest thermal conductivity. Moreover, it has a feature that it is excellent in elasticity and does not lose its electrical properties even if stretched or bent.

Referring to FIG. 2, the first layer 20 may be a single-layer graphene layer or at least one multilayer graphene (MLG) layer. The height of the graphene layer may be selectively controlled according to the type of the biosensor to be used .

Furthermore, it should be noted that the shape of this first layer 20 may be selected from flexible, planar, cylindrical, cylindrical, rectangular columnar, coiled, and combinations thereof, owing to the flexible nature of the graphene. Accordingly, the electrode for a biosensor according to the present invention is capable of sensing various biomaterials simultaneously with blood collection by fusing with an existing syringe, and can be applied to a new type of sampling tool and an integrated sensor system do.

On the other hand, it is preferable that the first layer 20 has a thickness in the range of 50 to 500 mu m, and this is because the first layer 20 can be applied to the electrode for biosensor more effectively when the first layer 20 has the thickness in the above range Because.

The carbon nanotubes 30 are vertically formed on the first layer 20. The carbon nanotubes 30 are carbon isotopes, each having a carbon atom bonded to another carbon atom in an hexagonal honeycomb pattern to form a tube shape, and have excellent mechanical characteristics, electrical characteristics, and field emission characteristics.

Various methods can be used to vertically form the carbon nanotubes 30 on the first layer 20. Among them, the inventors of the present invention (Patent No. 10-0851950, entitled: A method of forming an electron-emitting device using the electron-emitting device) is advantageous in that the position can be selectively controlled.

A second layer 40 may be formed on the carbon nanotube. The bio-material 50 may be supported or fixed on the second layer 40 in various manners. Biomaterials selected from the group consisting of enzymes, platamers, proteins, nucleic acids, microorganisms, cells, lipids, hormones, DNA, PNAs, RNAs and mixtures thereof may be used as the biomaterial 50, &Lt; / RTI &gt; may be used.

For example, referring to FIG. 1 (a), a specific enzyme is used as the biomaterial 50, and the second layer 40 discloses an electrode for a biosensor in which such a specific enzyme is supported or a fixed membrane is used . In FIG. 1 (a), a specific enzyme is shown to be immobilized or immobilized within the membrane. However, it should be noted that the position of the specific enzyme is not limited to this, and some or all of the enzyme may protrude above the membrane. According to this structure, since the enzyme is excellent in substrate specificity and has a characteristic of selectively reacting only with a specific molecule even in a mixture, it is possible to selectively detect an analyte (for example, blood glucose) do.

Referring to FIG. 1 (b), an electrode for a biosensor in which a biosensor 50 is not included and the second layer 40 'uses a selective permeable membrane containing no enzyme. With this configuration, it becomes possible to selectively detect disease-related gaseous substances in the living body (for example, nitrogen oxide and the like).

Referring to FIG. 1 (c), a biosensor 50 'is used in which a biosensor, a platemater, or a cell is directly supported or fixed on the carbon nanotube 30 and the second layer 40 is not used Electrode. With this configuration, sensitivity to trace analysis can be greatly improved by optimizing the amount and arrangement of the aptamer or antibody to be fixed by controlling the density of carbon nanotubes.

That is, in the case of the electrode for an electrochemical biosensor according to the present invention, the detection characteristics of the electrode for an electrochemical biosensor can be controlled by controlling at least one of the density, height, diameter and arrangement of the carbon nanotubes .

Meanwhile, the electrode for an electrochemical biosensor according to the present invention can be applied to a biosensor. And a reference electrode so that various types of biosensors can be manufactured.

<Production Example>

On the multilayer graphene, nickel is used as a catalyst metal for growth of carbon nanotubes, and heat treatment is performed to form a rolled nickel grain. Thereafter, carbon nanotubes are vertically formed on the multi-layer graphene. At this time, in the plasma reactor having the internal temperature of about 150 to 800 ° C. and the internal pressure of 2 Torr, the carbon nanotube was fixed at 0 V and the substrate was set at -600 V and the voltage of the transmission control electrode was supplied at + 30 sccm of acetylene (C ₂ H ₂ ) and 70 sccm of ammonia (NH ₃ ).

Graphene produced in this manner; And an electrode for a biosensor in which carbon nanotubes are formed are shown in Fig. FIG. 5 shows a photograph of a state in which the electrode for a biosensor manufactured in the above production example is applied to a cylindrical structure.

FIG. 4 is a photograph of an electrode for an electrochemical biosensor according to an embodiment of the present invention, in which a carbon nanotube is vertically formed on a multi-layer graphene by a scanning electron microscope.

Referring to FIG. 4, it can be seen that multi-layer graphenes are formed in the middle region, and carbon nanotubes are formed uniformly in the vertical direction on the multi-layer graphenes. That is, it can be seen that the carbon nanotubes are uniformly formed in the vertical direction so that the surface area of the electrode is greatly increased, and the effective electrode area is increased, thereby improving the electrocatalytic property.

FIG. 5 is a photograph showing a state in which an electrode for an electrochemical biosensor according to an embodiment of the present invention is applied to a columnar structure by a scanning electron microscope. FIG.

Referring to FIG. 5, it can be seen that an electrode for an electrochemical biosensor according to an embodiment of the present invention is effectively bonded to a cylindrical structure having a size of about 8 mm. That is, due to the flexible nature of graphene, the size and shape of the electrode for a biosensor can be easily controlled, and the bending rate of the bent shape can be controlled to provide various shapes such as a cylindrical shape and a coil shape, It can be seen that an electrode structure for a biosensor can be manufactured.

<Experimental Example>

In order to evaluate the electrocatalytic properties of the electrode for an electrochemical biosensor according to an embodiment of the present invention, the electrocatalytic property was evaluated using the five electrodes described below.

Electrode 1: Multi-layered graphene electrode without carbon nanotubes

Electrode 2: An electrode for an electrochemical biosensor (CNT on graphene) according to an embodiment of the present invention manufactured in the above-

Electrode 3: Disc type electrode (diameter 3 mm, MF-2012) made of glass carbon made by BAS Corporation

Electrode 4: Plate type carbon electrode of DROPSENS (diameter 4mm, DROPSENS C220AT)

Electrode 5: Plate type gold electrode of DROPSENS (Diameter 4mm, DROPSENS 110)

Specifically, a silver / silver chloride electrode was used as a reference electrode, a Pt wire having a diameter of about 250 μm was used as an auxiliary electrode, and a solution containing 1 mM K ₃ Fe (CN) ₆ solution and 0.1 M KCl Cyclic voltammetry (CV) was performed in a 0.1M PBS solution at a constant potential scanning speed of 100 mV / sec and varying potential scanning speeds.

As a result of analyzing the CV diagram of the redox reaction of the ferricyanide compound (Ferricyanide), the potential scan rate and the peak potential separation of the electrode for an electrochemical biosensor according to an embodiment of the present invention are independent of each other And the value is also close to the theoretical value of 56.5 mV.

That is, as shown in Table 1, the value of Epa - Epc (mV) was measured to be 80 mV in the case of the electrode 1, and the value of Epa - Epc (mV) in the case of the electrode 2 was measured to be 75 mV. The Epa - Epc (mV) value was measured at 465 mV. For electrode 4, the Epa - Epc (mV) value was measured at 165 mV. For electrode 5, the Epa - Epc (mV) value was measured at 80 mV.

Based on these results, it can be said that the electrode for an electrochemical biosensor according to an embodiment of the present invention has the best reversibility of the electrode reaction, and the electrocatalytic property is remarkably excellent as compared with the electrodes of the same carbon type It was found that the reversibility is better than that of the electrode composed of gold.

This is because the effective electrode area is increased by forming the carbon nanotubes vertically on the multi-layered graphenes, so that the electrocatalytic properties are improved.

Oxidation restoration Epa - Epc (mV) Epa (V) I (㎂) Epc (V) I (㎂) Electrode 1
(graphene) 0.275 44.0313 0.195 -49.6688 80 Electrode 2
(CNT on graphene) 0.275 61.9125 0.2 -71.9938 75 Electrode 3
(Free carbon) 0.11 6.0075 -0.355 -9.26938 465 Electrode 4
(carbon_SPE) 0.27 14.3506 0.105 -18.3438 165 Electrode 5
(gold_SPE) 0.225 17.2688 0.145 -20.75 80

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be readily apparent to those skilled in the art that the present invention can be modified and changed without departing from the scope of the present invention.

Claims (8)

Board;
A first layer comprising a graphene formed on the substrate;
Carbon nanotubes formed on the first layer; And
And a second layer located on the carbon nanotube and having a specific bio material fixed or supported thereon.
Electrochemical electrodes for biosensors.
The method according to claim 1,
Characterized in that the first layer is at least one multilayer graphene (MLG)
Electrochemical electrodes for biosensors.
3. The method according to claim 1 or 2,
Wherein the first layer is selected from the group consisting of a flexible planar, cylindrical, cylindrical, quadratic, coiled, and combinations thereof.
Electrochemical electrodes for biosensors.
3. The method according to claim 1 or 2,
Wherein the first layer is in a thickness range of 50 to 500 mu m.
Electrochemical electrodes for biosensors.
3. The method according to claim 1 or 2,
Characterized in that the carbon nanotubes are formed perpendicular to the first layer.
Electrochemical electrodes for biosensors.
3. The method according to claim 1 or 2,
Wherein the carbon nanotubes are controlled in at least one of density, height, diameter, and arrangement thereof,
Electrochemical electrodes for biosensors.
3. The method according to claim 1 or 2,
Wherein the bio material is selected from the group consisting of an antibody, an enzyme, an extramamer, a protein, a nucleic acid, a microorganism, a cell, a lipid, a hormone, DNA, PNA, RNA,
Electrochemical electrodes for biosensors.
An electrode for an electrochemical biosensor according to claim 1 or 2;
An auxiliary electrode; And
Characterized in that it comprises a reference electrode and is capable of detecting biomaterials by an electrochemical reaction.
Electrochemical biosensor.

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