KR101898215B1 - Carbon nanotube-graphene hybrid electrode which is transparent such that cells may be detected, and Preparation method and Use thereof - Google Patents

Abstract

The present invention relates to a graphene electrode formed on a substrate; A cluster of hydrophilicized carbon nanotubes that is vertically grown on the graphene electrode and has an open terminal end portion into which the liquid can flow in and out so that a capillary force is formed when the nanotube is immersed in the hydrophilic liquid, Wherein the group of carbon nanotubes are collected in a hydrophilic liquid and drawn out through the capillary force to form open ends of the adjacent carbon nanotubes to form a three-dimensional nanostructured A carbon nanotube-graphene hybrid electrode characterized by having a sub-population (s); And a production method and use thereof.
The carbon nanotube-graphene hybrid electrode of the present invention has a microstructure in which cells are adhered to each other through a group of carbon nanotubes having a wide hydrophilic surface area and a three-dimensional structure and having excellent electron transfer characteristics, This function can narrow the distance between the cell and the electrode, so that it can measure the minute electric signal of the cell with high sensitivity, and it can be made into a transparent carbon electrode, so that the cell can be observed.

Description

[0001] The present invention relates to a carbon nanotube-graphene hybrid transparent electrode capable of observing a cell, a method for producing the same,

The present invention relates to a carbon nanotube-graphene hybrid electrode, a method for producing the carbon nanotube-graphene hybrid electrode, and a use thereof.

Carbon nanotubes are tubular structures made of carbon, and all carbon atoms are exposed to the surface, so they are sensitive to microscopic physicochemical reactions and have the mechanical durability inherent in carbon materials. Due to these properties, carbon nanotubes are attracting attention in the field of nanotechnology, and studies on various device applications using them have been reported.

Particularly, a carbon nanotube transistor is composed of a source, a drain, and a gate electrode, and can measure the electrical conductivity of the carbon nanotube. Therefore, Can be detected by a signal. Therefore, it can be used in various fields such as gas sensor that can detect dangerous gas leakage, and is a high-sensitivity sensor capable of real-time measurement. Therefore, it can be applied in various fields and can be manufactured at a relatively low price compared to other sensor manufacturing methods Have.

The carbon nanotube transistor is fabricated using one strand grown horizontally or a small number of carbon nanotubes. At this time, when carbon nanotubes are grown vertically, they can be used as electrodes having excellent sensitivity characteristics. When the carbon nanotubes are more than a certain density, they grow vertically aligned (VA) due to strong interaction between the tubes. In this case, the effect of the surface area of the carbon nanotube, which is a one- At the same time, the advantages of the three-dimensional structure electrode in which carbon nanotubes are vertically aligned are also obtained. When the carbon nanotube electrode is applied to an electrochemical sensor, the electrode has a large surface area and at the same time has a limited diffusion inhibiting effect. It is also expected to show high efficiency as an electrode of a fuel cell. In addition, carbon nanotubes fabricated on metal can be used for fuel cells and displays, and can also be used as electron guns and ultra-small X-ray sources.

On the other hand, electrodes used for measuring electrical signals of conventional cells or living tissues are mostly made of a metal such as Au, Pt, or a semiconductor such as TiN or SiN. However, when metal or semiconductor is used, it is difficult to fabricate a three-dimensional structure. Therefore, most of the signals measured in the extracellular measurement have a small size.

To overcome this problem, the inventors intend to further modify the carbon nanotube-graphene hybrid electrode in which carbon nanotubes having high electron transfer characteristics and no toxicity to nerve cells are vertically grown on the graphene electrode.

It is an object of the present invention to provide a transparent carbon electrode capable of observing cells while having high hydrophilic surface area and excellent electron transfer characteristics capable of measuring fine electrical signals of cells with high sensitivity because the cells can stick to each other well.

A first aspect of the present invention provides a method of manufacturing a semiconductor device, comprising: a graphene electrode formed on a substrate; A cluster of hydrophilicized carbon nanotubes that is vertically grown on the graphene electrode and has an open terminal end portion into which the liquid can flow in and out so that a capillary force is formed when the nanotube is immersed in the hydrophilic liquid, Wherein the group of carbon nanotubes are collected in a hydrophilic liquid and drawn out through the capillary force to form open ends of the adjacent carbon nanotubes to form a three-dimensional nanostructured Carbon nanotube-graphene hybrid electrode characterized by having a sub-population (s).

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a first step of preparing a graphene electrode formed on a substrate; A second step of forming a carbon nanotube vertical growth catalyst layer on the graphene electrode; A third step of vertically growing carbon nanotubes on the catalyst layer; A fourth step of hydrophilizing the open end-containing region, from which the liquid can flow in and out, out of the vertically grown carbon nanotubes; And clusters of vertically grown and hydrophilized carbon nanotubes on the graphene electrode are immersed in a hydrophilic liquid, and the open ends of the adjacent carbon nanotubes are collected through capillary force to form three-dimensional nano- And a fifth step of forming a lower group (s) of the carbon nanotubes to which the structure is attached.

A third aspect of the present invention is a carbon nanotube-graphene hybrid electrode according to the first aspect of the present invention; And a cell attached on the carbon nanotube-graphene hybrid electrode.

In a fourth aspect of the present invention, there is provided a method for culturing or differentiating cells on a carbon nanotube-graphene hybrid electrode according to the first aspect of the present invention; And analyzing an electric signal generated from the cultured or differentiated cells.

Hereinafter, the present invention will be described in detail.

The carbon nanotube-graphene hybrid electrode according to the present invention comprises

A graphene electrode formed on a substrate; A cluster of hydrophilicized carbon nanotubes that is vertically grown on the graphene electrode and has an open terminal end portion into which the liquid can flow in and out so that a capillary force is formed when the nanotube is immersed in the hydrophilic liquid, A carbon nanotube-graphene hybrid electrode,

The group of carbon nanotubes includes a lower group (s) to which the open ends of the adjacent carbon nanotubes gather to form a three-dimensional nanostructure through capillary force while dewatered in a hydrophilic liquid.

The carbon nanotube-graphene hybrid electrode of the present invention compensates for disadvantages of conventional flat metal electrodes or semiconductor electrodes in order to measure fine electrical signals with high sensitivity from nerve cells spontaneously emitting electric signals, The nanotubes are hydrophilic and have a variety of three-dimensional nanostructures (for example, a curved surface at the distal end or a curved surface such as a cone having a blunt end cone) so that the cells can adhere well to a cluster of carbon nanotubes grown perpendicularly Hydrophobic carbon nanotubes are hydrophilically surface-modified, and capillary force is used by dipping them in a hydrophilic liquid (e.g., water) in order to impart a three-dimensional structure.

Further, in order to impart various three-dimensional nanostructures to a cluster of carbon nanotubes, (i) the number of sub-group (s) to which a three-dimensional nanostructure is imparted in a group of carbon nanotubes, (ii) (Iii) the slope of the carbon nanotubes with respect to the graphene electrode surface,

The length of each carbon nanotube, the density of carbon nanotubes in a group of carbon nanotubes, the method or degree of hydrophilic treatment of carbon nanotubes, and the type of hydrophilic liquid. Can be controlled.

Graphene is a two-dimensional structure composed of pure carbon. When formed as an electrode, it is impossible to obtain a thickness of one carbon atom, and high permeability can be secured. Therefore, the graphene electrode can serve as a transparent bottom electrode. When the carbon nanotube-graphene hybrid electrode of the present invention is used for cell culture, the cell shape, cell growth or cell differentiation can be confirmed by using the transparent characteristic of graphene. Therefore, the carbon nanotube-graphene hybrid electrode of the present invention can be used for observing morphology / growth / differentiation of cells, measuring electric signals of cells and / or applying electrical stimulation to cells, Can be applied to a device capable of analyzing the correlation between the input signal and the output signal. The cells may include stem cells, nerve cells.

In addition, graphene has the advantages of excellent theoretical electrical conductivity and durability, and excellent flexibility. Therefore, the carbon nanotube-graphene hybrid electrode of the present invention can be applied to a flexible device using a flexible substrate as a base material, and can be attached to or worn on the body. In addition, since the flexible and transparent graphene electrode is used, it can be used for a transparent flexible device.

The graphene electrode may be patterned to suit the use of the carbon nanotube-graphene hybrid electrode.

The substrate may be an insulating and / or transparent substrate, and / or may not be deformed at high temperatures. Non-limiting examples of the substrate include silicon, quartz, sapphire, tempered glass, alumina and the like.

2, the graphene electrode 3 may be connected to the power source through the base electrode 2, and the base electrode 2 may be patterned on the base material as shown in FIG. The patterned base electrode 2 can be formed by using a photolithography method. As the base electrode, a metal having a good junction with graphene and having no deformation even at a carbon nanotube synthesis temperature (600 to 700 ° C) is used . Specifically, a Cr / Pt electrode can be used.

On the other hand, carbon nanotubes have a high electron transfer characteristic, a low electrode impedance, and a high charge capacity. Hence, it is possible to make hetero-junctions free from graphene, Can solve the problem of resistance. The carbon nanotube electrode has a large surface area and at the same time has a limited diffusion inhibiting effect when used in an electrochemical sensor, so that an electrode having a much higher sensitivity than the conventional sensor can be manufactured. Therefore, the carbon nanotube electrode can be used for biological applications High utility. In addition, graphene and carbon nanotubes have stable biocompatibility and are not toxic to nerve cells. Therefore, the carbon nanotube-graphene hybrid electrode of the present invention can be used as an electrode for nerve electrical stimulation, and can be used for cell culture and / or biopsy.

Carbon nanotubes are classified into multi-walled carbon nanotubes, which are single-walled carbon nanotubes and multiple-wall carbon nanotubes concentrically formed according to their structures. Single-walled carbon nanotubes are 0.5 to 3 nm in diameter with a single layer of graphite plate. Double-walled carbon nanotubes have a diameter of 1.4 to 3 nm with two concentric single-walled carbon nanotubes , Multi-walled carbon nanotubes have a layer of 3 to 15 layers and a diameter of 5 to 100 nm.

The carbon nanotube-graphene hybrid electrode of the present invention has a cluster of carbon nanotubes as an object imparting various three-dimensional structures by vertically growing carbon nanotubes directly on predetermined regions on graphene electrodes .

The length of the vertical carbon nanotubes can be adjusted according to the growth time, and the position of the group of dense carbon nanotubes can be adjusted to a desired shape depending on the position of the catalyst layer for vertical growth of the carbon nanotubes.

At this time, a group of carbon nanotubes may be patterned on some predetermined portions of the patterned graphene electrodes.

Further, an insulating film may be formed on the graphene electrode except for a region where the group of carbon nanotubes exists.

The insulating film preferably has no deformation at the carbon nanotube synthesis temperature and is not toxic to the cells upon cell growth. It is also desirable to be a material that can be etched into a desired shape through a simple lithography method and wet etching. Non-limiting examples of the insulating film include SiO ₂ , Si ₃ N ₄ , and Al ₂ O ₃ .

The insulating film can isolate all the remaining portions except the portion where the carbon nanotubes are to be grown, so that the characteristics of the carbon nanotube-graphene hybrid electrode according to the present invention can be further improved. That is, by forming the insulating film, it is possible to control the reaction to occur only in the carbon nanotubes. Therefore, when applied to an electrochemical sensor, a much larger signal-to-noise ratio can be expected and leakage current irrespective of the reaction can be minimized.

Since the carbon nanotubes are hydrophobic, the present invention is characterized in that the surfaces of the carbon nanotubes are hydrophilically treated in order to enhance the cell adhesion ability to a group of hydrophobic carbon nanotubes and to impart various three-dimensional nanostructures through the capillary force.

Changes in the hydrophobic to the hydrophobic nature of Tannonanotube increase the C-O, C = O chemical bonds in the experiment in XPS. Also, the change from hydrophobic to hydrophilic can be confirmed by the water contact angle experiment.

Non-limiting examples of hydrophilic liquids for imparting capillary forces to groups of hydrophilicized carbon nanotubes include water, alcohols, and acetone.

The carbon nanotube-graphene hybrid electrode according to one embodiment of the present invention can directly synthesize a group of carbon nanotubes having high conductivity on a graphene bottom electrode having transparency and flexibility in a three-dimensional structure to form a seamless heterogeneous junction structure Thereby lowering the resistance therebetween, hydrophilizing the open end-containing portion of the vertically grown carbon nanotubes and gathering the open ends of the adjacent carbon nanotubes to give various nanostructures to the group of carbon nanotubes, A flat metal or semiconductor electrode that has been used predominantly, a surface that has a higher surface area than a three-dimensional metal electrode having a flat surface and on which the cells can adhere well.

In the present invention, the surface of the carbon nanotube electrode has a three-dimensional nanostructure, so that the surface of the carbon nanotube electrode has higher sensitivity than the surface of the carbon nanotube electrode having a two-dimensional surface structure.

In addition, the hydrophilic terminals of the adjacent carbon nanotubes are gathered and the three-dimensional nanostructure imparted to the group of carbon nanotubes can enhance the binding between the nerve cell and the carbon nanotube electrode, thereby measuring a large signal. In addition, carbon nanotubes have low electrode impedance, high charge capacity, and stable biocompatibility, so that they can be used as an electrode for neural electrical stimulation. As the flexibility properties of graphene are added thereto, It can also be used as an insertion electrode. That is, the vertically grown carbon nanotube-graphene electrode having transparency, three-dimensional and high sensitivity according to the present invention can be applied to the body when the device is manufactured using the flexible substrate together with the flexibility of the graphene.

Meanwhile, a method of manufacturing a carbon nanotube-graphene hybrid electrode according to the present invention includes

A first step of preparing a graphene electrode formed on a substrate;

A second step of forming a carbon nanotube vertical growth catalyst layer on the graphene electrode;

A third step of vertically growing carbon nanotubes on the catalyst layer;

A fourth step of hydrophilizing the open end-containing region, from which the liquid can flow in and out, out of the vertically grown carbon nanotubes; And

A cluster of vertically grown and hydrophilized carbon nanotubes on the graphene electrode is immersed in the hydrophilic liquid, and the open ends of the adjacent carbon nanotubes are collected through capillary force to form a three-dimensional nanostructure (S) of the carbon nanotubes to which they are attached.

In the first step, graphene may be transferred or directly grown on a substrate to form a graphene electrode.

In the first step, the graphene electrode may be graphene deposited on a low pressure chemical vapor deposition (LPCVD) or thermochemical vapor deposition, or a reduced oxide graphene.

The second step is to form a catalyst layer for inducing and promoting the growth of carbon nanotubes on the graphene electrode.

In the second step, the catalyst layer is not particularly limited as long as it can grow carbon nanotubes, but may be a transition metal compound, a metal and / or a semiconducting nanoparticle. These can grow carbon nanotubes of small diameter.

The catalyst layer may be formed on the graphene electrode, which is a bottom electrode, and the deposition may be performed in a vacuum chamber. However, the present invention is not limited thereto.

In one embodiment, the catalyst layer for vertical growth of carbon nanotubes in the second step may be a multi-layer structure including an aluminum thin film and an iron thin film, for example, a bilayer structure of Al / Fe.

At this time, the thickness of the aluminum thin film may be 5 to 15 nm. When the thickness is less than 5 nm, there is a problem that the aluminum thin film is oxidized and the electrical contact is bad. When the thickness is more than 15 nm, the process cost of growing the carbon nanotube increases, .

The thickness of the iron thin film may be 1 to 10 nm. When the thickness is less than 1 nm, the carbon nanotube grows horizontally or does not grow vertically. When the thickness exceeds 10 nm, the diameter of the carbon nanotube becomes too large or the carbon nanotube does not grow well .

The third step is to vertically grow the carbon nanotubes on the graphene electrode through the catalyst layer to form a group of carbon nanotubes in the catalyst layer forming region. At this time, it is preferable that the carbon nanotubes grow vertically, but the case where the carbon nanotubes grow at an angle to the graphene electrode surface falls within the scope of the present invention.

As compared with the carbon nanotubes grown horizontally with respect to the substrate surface, the vertically grown carbon nanotubes have an effect of achieving a higher contact area, and thus can maximally utilize the high specific surface area of the carbon nanotubes .

In the third step, carbon nanotubes can be grown by plasma chemical vapor deposition. The plasma chemical vapor deposition method is a method of performing glow discharge in a chamber or a reaction chamber by a high frequency power source applied to a positive electrode, which is performed by using plasma. This has the advantage of being able to synthesize carbon nanotubes at a low temperature as compared with the thermochemical vapor deposition method, and has the advantage of growing carbon nanotubes oriented perpendicularly to the substrate. Plasma chemical vapor deposition can be performed using methane gas as a carbon source at 600 to 700 ° C.

The fourth step is to change the surface of the carbon nanotubes having hydrophobic surface characteristics to hydrophilic.

The hydrophilic treatment can be performed by ultraviolet-ozone treatment or oxygen (O ₂ ) plasma treatment, and various known methods can be applied.

In the fifth step, a group of hydrophilicized carbon nanotubes is immersed in a hydrophilic liquid such as water and then withdrawn, while the open ends of adjacent carbon nanotubes are gathered through a capillary force to form a three-dimensional nanostructure A curved surface that is a curved surface, such as a curved cone, Dimensional structure of the carbon nanotubes) is formed.

In the fifth step, the number of sub-groups (s) to which the three-dimensional nanostructures are imparted in a group of (i) one carbon nanotubes, (ii) The slope of the graphene electrode surface may be selected from the group consisting of the length of each carbon nanotube, the density of carbon nanotubes in a group of carbon nanotubes, the method or degree of hydrophilic treatment of carbon nanotubes, and the type of hydrophilic liquid. And can be controlled through the capillary force.

In the first step, the graphene electrode may be patterned. For example, a graphene layer serving as a transparent bottom electrode may be transferred or directly grown on a transparent substrate, and patterned through photolithography to form a patterned graphene electrode.

In the second step, the catalyst layer may be patterned by forming an insulating layer on the graphene electrode of the first step, forming an oxide layer on the graphene electrode by removing the insulating layer on the region where the carbon nanotubes are vertically grown. Since the insulating film is removed to form the catalyst layer, the region of the insulating film to be removed is a region for forming the catalyst layer and is a region for forming the lower group (s) of the three-dimensional nanostructured carbon nanotubes. Accordingly, in the fifth step, the position of the sub-group (s) of the carbon nanotubes to which the three-dimensional nanostructures are imparted can be patterned corresponding to the catalyst layer pattern. The insulating film can be removed through etching.

Further, the present invention provides a carbon nanotube-graphene hybrid electrode according to the present invention; And a cell attached on the carbon nanotube-graphene hybrid electrode. At this time, since the cells can be cultured or differentiated from the kit, the kit can be used as a biomedical device on which a cell therapeutic agent is mounted.

The present invention also relates to a method for culturing or differentiating cells on a carbon nanotube-graphene hybrid electrode of the present invention; And

And analyzing an electric signal generated from the cultured or differentiated cells.

When the carbon nanotube-graphene hybrid electrode of the present invention is applied to a cell characteristic measuring apparatus, cells can be cultured or differentiated on a carbon nanotube-graphene hybrid electrode under various conditions, and at the same time, Cell analysis is possible.

The cell may be a cell capable of generating a spontaneous electrical signal or generating an electrical signal by electrical stimulation. In particular, the cell senses an electrical signal of a nerve cell spontaneously emitting an electrical signal, Device.

Before culturing the cells, the cell adhesion factor may be first treated on the surface of the carbon nanotube-graphene hybrid electrode of the present invention. As the cell attachment factor, poly-D-lysine can be used. In addition, suitable cell attachment factors can be selected and used according to the used cells.

The carbon nanotube-graphene hybrid electrode of the present invention has a microstructure in which cells are adhered to each other through a group of carbon nanotubes having a wide hydrophilic surface area and a three-dimensional structure and having excellent electron transfer characteristics, This function can narrow the distance between the cell and the electrode, so that it can measure the minute electric signal of the cell with high sensitivity, and it can be made into a transparent carbon electrode, so that the cell can be observed.

1 is a plan view of a carbon nanotube-graphene hybrid electrode according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a carbon nanotube-graphene hybrid electrode according to an embodiment of the present invention taken along AA 'and B-B' in FIG. 1.
3 is a series of cross-sectional views illustrating a manufacturing process of a carbon nanotube-graphene hybrid electrode according to an embodiment of the present invention. 3A is a cross-sectional view in which a Cr / Pt electrode 2 is patterned as a base electrode on a transparent insulating substrate 1. 3B is a cross-sectional view of the graphene electrode 3 patterned by bonding to the Cr / Pt electrode 2. 3C is a cross-sectional view in which an insulating film 4 is formed on the Cr / Pt electrode 2 and the graphene electrode 3. FIG. 3D is a sectional view in which an Al / Fe catalyst layer 5 for vertically growing carbon nanotubes is formed on the graphene electrode 3 exposed after etching the insulating film 4 at a specific region on the graphene electrode 3.
FIG. 4 is a graph illustrating a change in surface characteristics of a carbon nanotube grown on a catalyst layer before and after UV-ozone treatment in the process of fabricating a carbon nanotube-graphene hybrid electrode according to Example 1. FIG. Here, (a) and (b) are XPS analysis results, and (c) are contact angle measurement results.
FIG. 5 (a) is a photograph of the carbon nanotube-graphene hybrid electrode fabricated in Example 1, and FIG. 5 (b) is a conceptual diagram showing a state in which nerve cells are adhered and cultured on the electrode fabricated in Example 1, FIG. 5 (c) (low magnification) and FIG. 5 (d) (high magnification) are electron micrographs of the electrode manufactured in Example 1.
6 (a), (b), (b), and (c) after the treatment of the aqueous solution, the surface morphology of the vertically grown carbon nanotubes in the process of fabricating the carbon nanotube- , And (d) after oxygen (O ₂ ) plasma treatment. (c) and (d), it can be seen that the group of the tan nanotube having the modified structure has stronger plasma resistance than the structure before having the deformed structure. This results in a hydrophilic surface strengthening and cleaning effect that can efficiently adhere cell adhesion factors for cell culture during a short time (1-2 minutes) plasma treatment.
FIG. 7 shows the results of observing growth of neurons on the electrodes prepared in Example 1 for 28 days.
8 is a fluorescence microscope photograph (a) and an electron microscope photograph (b) of neurons attached to the electrode on the 7th day of growth.
FIG. 9 shows electrical signals measured from neurons at 7 days after culturing. Here, E01, E28, and E29 are different electrodes.
10 is a signal recorded on a three-dimensional VACNT electrode having a nanoscale surface modified in Example 1 compared to a signal recorded on a flat commercial electrode. (a) Signals of representative VACNTs electrodes (diameter: 5 μm, height: 7-10 μm) and flat commercial electrodes (TiN, diameter: 30 μm) were recorded at 27 DIV and 28 DIV, respectively. (b) The maximum spike amplitude of the VACNT electrode ( n = 5) was approximately 1.2 mV, while the corresponding value obtained on the commercial electrode ( n = 5) was barely 218 μV. (c) and (d) are the corrected spikes detected using a VACNTs electrode and (d) a flat TiN electrode as a function of the amplitude (inset: number of detected spikes versus the spike amplitude). ** P < 0.01

Hereinafter, the present invention will be described in more detail with reference to Examples. These embodiments are only for describing the present invention more specifically, and the scope of the present invention is not limited by these examples.

Example  One: Grapina  When carbon nanotubes are vertically grown on the electrode hybrid  Manufacture of electrodes

According to the manufacturing process illustrated in FIG. 3, a hybrid electrode having carbon nanotubes grown vertically on a transparent graphene electrode was fabricated.

First, methane (CH ₄ ) gas and hydrogen (H ₂ ) gas are flowed at a ratio of 1: 1 (30: 30 sccm) at 1000 ° C. for 40 minutes through a low pressure chemical vapor deposition (LPCVD) process on a copper film having a thickness of 10 μm The graphene film was synthesized.

The graphene film was transferred onto a quartz substrate prepared by patterning Cr / Pt (10/30 nm) electrodes using a polymethyl methacrylate (PMMA) -substrate wet transfer method, and a photolithography method and an Ar / O ₂ (1: 5, v / v) mixed gas for 20 minutes to pattern the graphene electrode into a desired electrode shape.

An SiO ₂ insulating film of about 500 nm was formed on the substrate having the patterned graphene electrodes by using a plasma-enhanced chemical vapor deposition (PECVD) method. A window was formed by wet etching an insulating film on a graphene electrode in a region where vertical growth of carbon nanotubes was desired by photolithography. Al / Fe (8: 1.4 nm), which is a growth catalyst of carbon nanotubes, Deposition was carried out through the window and the rest of the window was removed through acetone.

Carbon nanotubes were vertically grown at about 650 ° C. by plasma enhanced chemical vapor deposition (PECVD) on a graphene electrode on which a catalyst was deposited by using methane gas as a carbon source. The radius and the length of each vertically grown carbon nanotube electrode were controlled according to the catalyst pattern and growth time.

The surface properties of the vertically grown carbon nanotubes were hydrophobic, so the surface properties were changed to hydrophilic by performing ultraviolet-ozone treatment for about 20 minutes.

The carbon nanotubes vertically grown on the surface of the graphene electrode through the capillary force in the process of dipping the vertically grown and hydrophilized carbon nanotubes into water are formed into a curved surface such as a cone, Dimensional nanostructure (s).

Experimental Example  One: Hydrophilic  Carbon nanotubes - Grapina hybrid  Analysis of electrode surface characteristics

After the carbon nanotubes were vertically grown on the graphene electrode according to Example 1, the XPS and water contact angles were measured before and after the UV-ozone treatment of the surface of the carbon nanotubes. Ultraviolet-ozone treatment was followed by XPS and water contact angles.

The results are shown in Fig. Here, (a) and (b) are XPS analysis results and (c) are contact angle measurement results.

4, it can be seen that the surface of the vertically grown carbon nanotubes is changed to hydrophilic by ultraviolet-ozone treatment.

Experimental Example  2: Grapina  A carbon nanotube-like structure having a three-dimensional nanostructure (s) such as a cylinder having curved ends formed by collecting ends of vertically grown carbon nanotubes on an electrode, Grapina hybrid  Electrode Imaging

5 (a) is a photograph of the carbon nanotube-graphene hybrid electrode fabricated in Example 1 above. FIG. 5 (b) conceptually shows the attachment of nerve cells on the carbon nanotube-graphene hybrid electrode fabricated in Example 1. FIG.

5 (c) (low magnification) and 5 (d) (high magnification) images of the carbon nanotube-graphene hybrid electrode fabricated in Example 1 were observed under an electron microscope. As a result, carbon nanotube groups are partially formed on the patterned graphene electrode, and carbon nanotubes are vertically grown on specific regions of the graphene electrode to form a group of carbon nanotubes. Of the carbon nanotubes are gathered.

Experimental Example  3: Analysis of shape change of carbon nanotube electrode surface

The surface morphology of vertically grown carbon nanotubes was investigated immediately after growth, after ultraviolet-ozone treatment, and after aqueous solution treatment in the process of fabricating carbon nanotube-graphene hybrid electrodes according to Example 1 above. The surface morphology of vertically grown carbon nanotubes after oxygen (O ₂ ) plasma treatment was also investigated.

In FIG. 6, (a) shows the state immediately after growth, (b) shows ultraviolet-ozone treatment, (c) shows aqueous solution treatment, and (d) shows oxygen (O ₂ ) plasma treatment.

6 (c) and 6 (d), when the vertically grown carbon nanotubes are subjected to the hydrophilic treatment and the aqueous solution treatment, the three-dimensional nanostructures including the ends of the carbon nanotubes are formed. In addition, it has strong plasma resistance and can efficiently attach a cell attachment factor for cell culture during a short time (1-2 minutes) plasma treatment.

Experimental Example  4: Carbon nanotubes - Grapina hybrid  Signal measurement of nerve cells using electrodes

Electrical signals of nerve cells were measured using a carbon nanotube-graphene hybrid transparent electrode fabricated as in Example 1 above.

For signal measurement of the cells, the surface of the hybrid transparent electrode of Example 1 was coated with poly-D-lysine, and neural cells of SD rats were cultured.

7, it can be confirmed that the neuron grows well on the VACNT-graphene hybrid transparent electrode for about one month.

A fluorescence microscope (a) and an electron micrograph (b) of the neurons attached to the electrode on the 7th day of growth are shown in Fig. Cells are well grown on carbon nanotube-graphene hybrid transparent electrodes.

In addition, spontaneous spikes of nerve cells can be seen from the electrical signals measured at 7 days after culturing through Fig. In Fig. 9, E01, E28 and E29 are different electrodes.

10 is an environment in which cells can not be grown when the hydrophilic treatment is not carried out. FIG. 10 shows data obtained by comparing the conventional commercial TiN electrode with the Tannonanotube-graphene hybrid electrode.

1: transparent insulating substrate 2: Cr / Pt electrode
3: graphene electrode 4: insulating film
5: Al / Fe catalyst layer 6: vertically grown carbon nanotubes

Claims (20)

A graphene electrode formed on a substrate; A cluster of hydrophilicized carbon nanotubes that is vertically grown on the graphene electrode and has an open terminal end portion that can flow in and out to form a capillary force when immersed in the hydrophilic liquid and then withdrawn, A carbon nanotube-graphene hybrid electrode,
The carbon nanotube-graphene hybrid electrode is transparent enough to confirm cell morphology, cell growth or cell differentiation, and the population of carbon nanotubes is immersed in a hydrophilic liquid, A carbon nanotube-graphene hybrid electrode comprising a plurality of open end-assemblies and a bottom group (s) provided with a truncated conical three-dimensional nanostructure. The method of claim 1, wherein the number of sub-groups (s) to which the three-dimensional nanostructures are imparted in a population of carbon nanotubes, (ii) the three-dimensional nanostructured form of the sub-population, or (iii) The inclination of the carbon nanotubes on the surface of the graphene electrode is one of the group consisting of the length of each carbon nanotube, the density of the carbon nanotubes in one group of carbon nanotubes, the method or degree of hydrophilic treatment of the carbon nanotubes, Wherein the carbon nanotube-graphene hybrid electrode is controlled by capillary force. The carbon nanotube-graphene hybrid electrode according to claim 1, wherein the carbon nanotube-graphene hybrid electrode is used for culturing cells. The carbon nanotube-graphene hybrid electrode according to claim 1, which is used for culturing neurons. The carbon nanotube-graphene hybrid electrode of claim 1, wherein the graphene electrode is patterned. 6. The method of claim 5, wherein a cluster of carbon nanotubes hydrophilically treated at a predetermined portion of the patterned graphene electrode is patterned, and the graphene electrode portion except for the region where the group of carbon nanotubes exist is Wherein an insulating film is formed thereon. The carbon nanotube-graphene hybrid electrode according to claim 1, wherein the hydrophilic treatment is a UV-Ozone treatment or an O ₂ plasma treatment. The carbon nanotube-graphene hybrid electrode according to claim 1, wherein the substrate is a flexible substrate. The carbon nanotube-graphene hybrid electrode according to claim 1, which is for implantation. 10. The carbon nanotube-graphene hybrid electrode according to any one of claims 1 to 9, wherein the carbon nanotube-graphene hybrid electrode is used for imparting electric stimulation to cells or for detecting electric signals of cells.
A first step of preparing a graphene electrode formed on a substrate;
A second step of forming a carbon nanotube vertical growth catalyst layer on the graphene electrode;
A third step of vertically growing carbon nanotubes on the catalyst layer;
A fourth step of hydrophilizing the open end-containing region, from which the liquid can flow in and out, out of the vertically grown carbon nanotubes; And
A cluster of vertically grown and hydrophilized carbon nanotubes on the graphene electrode is immersed in a hydrophilic liquid and then drawn out to form open ends of adjacent carbon nanotubes through a capillary force, A fifth step of forming a lower group (s) of carbon nanotubes to which a conical three-dimensional nanostructure is imparted; a carbon nanotube-graphene hybrid electrode which is transparent enough to confirm cell morphology, cell growth or cell differentiation &Lt; / RTI &gt; 12. The method of claim 11, wherein in the fifth step, (i) the number of sub-population (s) to which the three-dimensional nanostructures are imparted in a population of carbon nanotubes, (ii) iii) The slope of the carbon nanotubes with respect to the graphene electrode surface depends on the length of each carbon nanotube, the density of the carbon nanotubes in a group of the carbon nanotubes, the method or degree of hydrophilic treatment of the carbon nanotubes, Wherein at least one of the carbon nanotube-graphene hybrid electrode and the carbon nanotube-graphene hybrid electrode is selected and controlled through capillary force. 12. The method of claim 11, wherein the graphene electrode is patterned in a first step. 12. The method of manufacturing a carbon nanotube-graphene hybrid electrode according to claim 11, wherein the position of the lower group (s) of the carbon nanotubes to which the three-dimensional nanostructures are imparted in the fifth step is patterned corresponding to the catalyst layer pattern Way. 12. The method of claim 11, wherein in the second step, the catalyst layer is formed by forming an insulating layer on the graphene electrode in the first step, removing the insulating film on the graphene electrode in a region where the carbon nanotubes are vertically grown, Wherein the carbon nanotube-graphene hybrid electrode is a carbon nanotube-graphene hybrid electrode. 12. The method of manufacturing a carbon nanotube-graphene hybrid electrode according to claim 11, wherein the graphene electrode in the first step is graphene or reduced graphene deposited by low pressure chemical vapor deposition (LPCVD) or thermochemical vapor deposition . The carbon nanotube-graphene hybrid electrode according to any one of claims 1 to 9; And a cell attached on the carbon nanotube-graphene hybrid electrode. 18. The kit according to claim 17, wherein the cells are cultured or differentiated. 18. The kit according to claim 17, wherein the carbon nanotube-graphene hybrid electrode is treated with a cell adhesion factor. Culturing or differentiating cells on the carbon nanotube-graphene hybrid electrode according to any one of claims 1 to 9; And
And analyzing an electrical signal generated from the cultured or differentiated cells.

Images