KR101365108B1 - Multi scrolled yarn electrode fiber and its preparing method - Google Patents

Abstract

The present invention relates to electrode fibers of a twisting structure for providing enhanced catalytic activities, mechanical strength, activities in in-vivo environments, and electrode performance, and a manufacturing method thereof, characterized by including: a carbon nanotube sheet coated with a conductive polymer; and an enzyme fixed to the carbon nanotube sheet, and formed in a multilayered structure. The electrode fibers according to the present invention have excellent mechanical strength enough to manufacture textile, and are able to be easily applied to in-vivo environments, as well as have remarkable electrode performance so as to include an implantable form such as a syringe needle, a catheter, a stent and the like. Therefore, if the electrode fibers are applied as biological fuel cells and various medical devices or mediums, remarkable performance enhancement can be produced.

Description

Multi-scrolled yarn electrode fiber and its preparing method

The present invention relates to a twisted structure of the electrode fiber and a method for manufacturing the same, and more particularly, including a multilayer and porous structure and twisted structure, providing high electrode performance through improved catalytic activity and excellent mechanical strength The present invention relates to a twisted structure electrode fiber that can be driven in a living environment and a method of manufacturing the same.

Biofuel cell (BFC) is a micro device that converts biological energy into electrical energy, and has been in the spotlight as a power source for implantable biomedical devices including pacemakers, nerve stimulators, and drug delivery pumps (A. Heller, Miniature biofuel cells, Physical Chemistry Chemical Physics. 6 (2004) 209., I. Ivanov, T. Vidakovic-Koch, K. Sundmacher, Recent Advances in Enzymatic Fuel Cells: Experiments and Modeling, Energies. 3 (2010) 803-846 .). However, until recently, BFC has shown technical limitations due to low power, short uptime and poor mechanical properties.

The performance of the BFC is improved by increasing the amount of electrogenerated enzyme immobilized on the electrode, by increasing the active surface area of the electrode using nanostructured materials, or by designing to facilitate the transfer of electrons from the enzyme to the external circuit. Can be. In particular, the surface structure of the electrode plays a decisive role in the ability of electrons to move from the enzyme to the electrode body. Therefore, the surface structure of the BFC electrode should have a high active surface area and at the same time have a high conduction property to provide efficient current flow. Therefore, development efforts are active. In addition, the development of flexible and highly active electrodes can extend BFCs to implantable or portable devices (T. Miyake, S. Yoshino, T. Yamada, K. Hata, M. Nishizawa, Self- regulating enzyme-nanotube ensemble films and their application as flexible electrodes for biofuel cells., Journal of the American Chemical Society.133 (2011) 5129-34.).

In order to achieve this, as a prior art, a technique has been disclosed in which a multipurpose fiber manufactured through a biscrolling process can be applied as an electrode material in the energy field including BFC (MD Lima, S. Fang, X. Lepro). , C. Lewis, R. Ovalle-Robles, J. Carretero-Gonz ㅱ lez, et al., Biscrolling nanotube sheets and functional guests into yarns., Science.331 (2011) 51-5.). The technique uses a multi-walled carbon nanotube (MWNT) membrane with a large surface area, functionally designed nanomaterials, and highly active MWNT-nanomaterials by twist-spinning them together. A method of making hybrid fibers is disclosed. The "twisting" process imparts compressive stress to the MWNT-nanomaterials to bring them into close contact, and the fibers thus produced are expected to improve the charge trapping capacity and durability as electrode materials. Despite these advantages, however, the technique is not readily available in the biological environment. This is because biomaterials that can be manipulated in an aqueous solution environment are not invasive to hydrophobic MNWTs (M. Zhang, S. Fang, A. a Zakhidov, SB Lee, AE Aliev, CD Williams, et al., Strong, transparent, multifunctional, carbon nanotube sheets., Science.309 (2005) 1215-9.), This limitation of fibers made according to the above technique is a fatal flaw in its application to BFC.

The above limitations are not the only techniques described. The electrode materials for BFC developed to date do not satisfy all of applicability, durability, hydrophilicity, flexibility, and high activity in the biological environment, and efforts to develop them to improve the technology in the field of BFC are being actively made. .

The first problem to be solved by the present invention is to provide a fine-phase electrode fibers that can be easily applied in a living environment, excellent mechanical strength and excellent electrode performance.

The second object of the present invention is to provide a method for producing the electrode fiber.

The third problem to be solved by the present invention is to provide an electrode fabric exhibiting excellent efficiency of the adsorbed catalyst while retaining the bio-operational ability by including the electrode fibers.

The fourth problem to be solved by the present invention is to provide a biofuel cell which can be easily downsized by including the electrode fibers, retains bio-operational capability and exhibits excellent power generation efficiency.

The fifth problem to be solved by the present invention is the implantable form of BFC, such as a needle, catheter, stent, etc., which can be easily downsized by including the electrode fibers, retaining the bio-operational performance and excellent device performance And to provide a bioelectrode.

In order to solve the above problems,

Provided is an electrode fiber comprising a carbon nanotube sheet coated with a conductive polymer and functional particles adsorbed on the carbon nanotube sheet, and having a multilayer structure.

According to an embodiment of the present invention, the electrode fiber may be in the form of a yarn prepared by twisting the carbon nanotube sheet, the multi-layer structure may be formed in the process of twisting the carbon nanotube sheet in the form of a yarn.

According to an embodiment of the present invention, the conductive polymer may be selected from poly (3,4-ethylenedioxythiophene), polyaniline, polypyrrole, polyethylene, and polythiophene.

According to one embodiment of the present invention, the adsorbed functional particles are selected from enzymes capable of redox, such as glucose oxidase and bilirubin oxidase.

According to an embodiment of the present invention, the electrode fiber may further include an osmium (Os) -based redox mediator, and the redox mediator may be (poly (N-vinylimidazole) -[Os (4,4'-dimethoxy-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} and (poly (acrylic acid) -poly (N-vinylimidazole)-[Os (4 , 4'-dichloro-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} .

According to an embodiment of the present invention, the electrode fiber may simultaneously include an oxidation electrode and a reduction electrode in one piece.

The present invention also provides a biofuel cell or implantable form of bioelectrode, such as a needle, catheter, or stent, including the electrode fiber as an anode electrode, a cathode electrode, or an anode / cathode integrated electrode.

Further, in order to solve the above problems,

a) preparing a carbon nanotube sheet, and coating a conductive polymer on the carbon nanotube sheet,

b) immersing the carbon nanotube sheet coated with the conductive polymer in a mixed solution containing an enzyme, a redox electron mediator and a crosslinking agent, and then adsorbing the enzyme and the redox electronic mediator on the carbon nanotube sheet;

c) twisting the carbon nanotube sheet (twist) to provide an electrode fiber manufacturing method comprising the step of producing an electrode fiber of a multi-layer structure.

According to an embodiment of the present invention, the step a) may be a prepared carbon nanotube sheet is a high-density carbon nanotube sheet formed by evaporating the alcohol in the carbon nanotube airgel sheet,

The conductive polymer may be coated on a carbon nanotube sheet through vapor-phase polymerization.

According to one embodiment of the present invention, the conductive polymer may be selected from poly (3,4-ethylenedioxythiophene), polyaniline, polypyrrole, polyethylene and polythiophene.

According to one embodiment of the present invention, the mixed solution of step b) is one or more enzymes selected from glucose oxidase and bilirubin (bilirubin) oxidase, and (poly (N-vinylimidazole)-[Os ( 4,4'-dimethoxy-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} and (poly (acrylic acid) -poly (N-vinylimidazole)-[Os (4,4'- Dichloro-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} may be one containing a redox electron mediator and a poly (ethylene glycol) diglycidyl ether crosslinking agent.

According to an embodiment of the present invention, the step c) may be to form the yarn by twisting the carbon nanotube sheet (twist), the multi-layer structure may be formed in the process of twisting in the yarn form.

Electrode fiber according to the present invention is easy to adsorb a water-soluble material, excellent mechanical strength, excellent electrode performance, and thus can be processed into various forms, such as fabric, embedded in a variety of medical devices, including needles, catheters, stents This can lead to excellent performance improvement when applied to various medical devices or media including biofuel cells and bioelectrodes.

1 is a view showing the structure (a, b) and the electrical activity (c, d) of the redox electron media contained in the electrode fiber according to an embodiment of the present invention.
2 is a conceptual diagram (a, f) of the electrode fiber according to an embodiment of the present invention, scanning electron microscope images (b, c) of the surface, scanning electron microscope images (d, e) of the cross section.
Figure 3 is a graph showing the measurement of the mechanical strength of the electrode fiber according to an embodiment of the present invention.
Figure 4 is a graph measuring the change in the current density represented by the electrode fiber according to the content ratio of the enzyme to the redox electron media in the electrode fiber according to an embodiment of the present invention.
5 is a graph in which the electrode fiber according to the embodiment of the present invention measures the change in current density or output density of each electrode according to the content of glucose in the buffer solution or the type of saturated gas.
Figure 6 is a carbon nanotube surface scanning electron microscope image before and after the adsorption of the enzyme, the redox electron media, and the crosslinking agent after coating the carbon nanotubes with the conductive polymer during the manufacturing process of the electrode fiber according to an embodiment of the present invention to be.
7 is a graph (a) of measuring a change in output density exhibited over time by a BFC prepared by using an electrode fiber according to an embodiment of the present invention, as an electrode fiber according to an embodiment of the present invention. Graph (b) measured by comparing the power and voltage output from the woven electrode fabric with a series connection structure, an exemplary conceptual diagram (c) of a double helix type BFC comprising an electrode fiber according to an embodiment of the present invention, and Image (d) of an electrode fabric woven with electrode fibers according to one embodiment of the invention.

The electrode fiber according to the present invention has excellent mechanical strength, has a hydrophilic surface, high adsorption effect of a water-soluble material, high activity in a living environment, and excellent performance as an electrode including a current density to output.

Hereinafter, the structural features of the electrode fiber according to the present invention will be described in detail.

The electrode fiber of the present invention is an electrode fiber comprising carbon nanotubes, conductive polymers coated on the carbon nanotubes, and enzymes fixed thereto, wherein the electrode fibers are formed by twisting the carbon nanotube sheets. In particular, a multi-layer structure (layer-by-layer) is formed in the process of twisting into a thread form, characterized in that consisting of a multi-layer structure.

According to a preferred embodiment, the carbon nanotube sheet is twisted at 1 to 6000 twist / m can be formed in a multi-layer structure.

The carbon nanotube sheet is a part constituting the basic body of the electrode fiber according to the present invention, while supporting a variety of containing elements to be described later, including the porous and multilayer structure to increase the active surface area of the electrode fiber, Therefore, it plays a role in making the supported elements more active.

Therefore, any carbon carrier as well as carbon nanotubes that provide the above characteristics can be selected and used without limitation, but in order to implement or reproduce the present invention, preferably carbon nanotubes are used, and more preferably carbon nanotubes. Multi-layered carbon nanotube aerosol sheets made from multi-layered carbon nanotube forests can be used.

The conductive polymer is originally coated on the carbon nanotube sheet having a hydrophobic surface to provide a hydrophilic surface. The conductive polymer may be at least one selected from the group consisting of poly (3,4-ethylenedioxythiophene), polyaniline, polypyrrole, polyethylene, and polythiophene, and more preferably poly (3,4-ethylene Deoxythiophene) (hereinafter referred to as 'PEDOT'). PEDOT is a conductive polymer that is a hydrophilic polymer, exhibits high electrical conductivity and transparency, and is flexible and easy to be applied to fields requiring high strength such as fibers.

In addition, the enzyme is a catalyst material that generates electrons by promoting oxidation of a target substance as a fuel, and the like, and may be one or more enzymes selected from glucose oxidase and bilirubin oxidase having suitable catalytic ability, and more preferably. Preferably, it may include glucose oxidase for the anode electrode for the biofuel cell, or bilirubin oxidase for the cathode electrode for the biofuel cell, and may include all for forming an integrated electrode.

As will be described later in the Examples, the present inventors have selected that the combination of the anode and the cathode, it was confirmed that when applied to a biofuel cell using glucose as a fuel material shows an optimized efficiency.

The electrode fibers according to the invention are (poly (N-vinylimidazole)-[Os (4,4'-dimethoxy-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} and (poly ( At least one redox electron mediator selected from acrylic acid) -poly (N-vinylimidazole)-[Os (4,4'-dichloro-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} redox mediator) may be further included.

The inclusion of redox electron mediators can facilitate the transfer of electrons or charges in the electrode fibers, which in turn results in improved performance as electrodes. As the redox electron mediator, a material that easily moves electrons or charges but does not interfere with the movement of materials should be selected. Preferably, an osmium (Os) -based material may be selected, and more preferably, a redox for anode As the electron mediator, (poly (N-vinylimidazole)-[Os (4,4'-dimethoxy-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} is a redox electron mediator for cathode Can be applied by selecting (poly (acrylic acid) -poly (N-vinylimidazole)-[Os (4,4'-dichloro-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} as have.

As will be described later in the Examples, the inventors have found that the combination of these anode or cathode redox electron mediators exhibits optimized efficiency when applied to biofuel cells.

In addition, the electrode fibers according to the invention may further comprise a cross-linker such as poly (ethylene glycol) diglycidyl ether. By including such a crosslinking agent, the carbon nanotube sheet, the conductive polymer, the redox electron media or the enzyme can be more firmly bonded, and without limitation, as long as it can perform such a role without interfering with the movement of materials or electrons. It may be selected, but preferably poly (ethylene glycol) diglycidyl ether may be selected.

The electrode fiber according to the present invention exhibits a twisted structure. As will be described later in the manufacturing process, the electrode fibers according to the present invention by providing a twisting-method to the carbon nanotube sheet adsorbed such as enzymes, conductive polymers, redox electron media or crosslinking agents 1 to 6000 It is formed into a fibrous form that exhibits twist / m.

Due to this twisted structure, a compressive stress is imparted between materials such as carbon nanotube sheets, enzymes, conductive polymers, redox electron media or crosslinking agents included in the electrode fibers according to the present invention. It is more physically in close contact to facilitate the transfer of charge, electrons or materials, while at the same time the electrode fibers acquire multiple layers and porous structures. This specific structure makes the electrode fibers according to the invention mechanically more robust, expands the active surface area, and facilitates the movement of electrons, charges or materials, thereby significantly improving electrode or catalytic activity.

Hereinafter, a method of manufacturing the electrode fiber according to the present invention will be described in detail.

The method for producing an electrode fiber according to the present invention includes the following steps.

a) preparing a carbon nanotube sheet, and coating a conductive polymer on the carbon nanotube sheet,

b) immersing the carbon nanotube sheet coated with the conductive polymer in a mixed solution containing an enzyme, a redox electron mediator and a crosslinking agent, and then adsorbing the enzyme and the redox electronic media on the carbon nanotube sheet;

c) twisting the carbon nanotube sheet to produce electrode fibers having a multilayer structure.

First, as a step, to prepare a carbon nanotube sheet to be used as a support of the electrode fiber according to the present invention. Although it is possible to purchase a planar or multilayer planar porous carbon nanotube sheet directly, it is preferable to prepare a carbon nanotube aerogel sheet by drawing from a carbon nanotube forest. The carbon nanotube airgel sheet thus formed has a planar structure and includes an empty space between the carbon nanotube unit fibers, and when used as an electrode, the surface area improvement effect is further improved.

Next, the surface of the carbon nanotube is coated with a conductive polymer to impart hydrophilicity to the surface. Carbon nanotubes are basically hydrophobic materials having a surface tension of 40 to 80 mN / m, and when used as an electrode material of a biofuel cell, they cannot have wettability as much as possible to operate. Therefore, in the present invention, a polymer capable of imparting a hydrophilic surface is coated on the surface of the carbon nanotube sheet. As a specific process for this, it is possible to coat the conductive polymer, for example by using a vapor-phase polymerization (vapor-phase polymerization).

However, if the above object can be achieved even through the process except the vapor phase polymerization method, the present invention is not limited by this coating method.

Next, as a step b), the step of adsorbing these substances by immersing the coated carbon nanotube sheet in a mixed solution of an enzyme, a redox electron mediator, or a crosslinking agent for a predetermined time. Matters relating to the selection of these materials will be replaced with those described above in the description of the construction of the present invention, and those skilled in the art to reproduce or implement the present invention may use a solution in which these are appropriately selected or mixed.

In a preferred embodiment, 41% by weight of GOx (glucose oxidase), 52% by weight of (poly (N-vinylimidazole)-[Os (4,4'-dimethoxy-2,2'-bi Pyridine) ₂ Cl]) ^{+ / 2 +} (redox electron mediator) and 7% by weight of poly (ethylene glycol) diglycidyl ether (crosslinking agent) can be prepared and another embodiment For example, 41 wt% BOD (bilirubin oxidase), 53 wt% (poly (acrylic acid) -poly (N-vinylimidazole)-[Os (4,4'-dichloro-2,2'- Bipyridine) ₂ Cl]) ^{+ / 2 +} (redox electron mediator) and 5% by weight of poly (ethylene glycol) diglycidyl ether (crosslinker) can be prepared for a cathode mixed solution.

The carbon nanotube sheet coated with the conductive polymer is immersed in these solutions for a certain time. The invention is not limited by additional circumstances, including the time of immersing the carbon nanotube sheet in solution, but may be made at 0 to 10 ° C. for a time and temperature environment, preferably 12 to 36 hours, at which the materials will be sufficiently adsorbed. have.

Next, as step c), twisting the carbon nanotube sheet to which the materials of step b) are adsorbed to produce electrode fibers having a multilayer structure. Such a process may be achieved by rotating both ends of the carbon nanotube sheet in opposite directions, or by fixing both ends, but rotating only the opposite ends. That is, as long as it can impart twist to the carbon nanotube sheet, it can be used without limitation, and the present invention is not limited by the process or device for implementing the same. This twisting process is not limited so long as it is possible to realize the above-mentioned characteristic elements of the present invention (compression stress, adhesion of materials, improvement of electron or material mobility, or multilayer and porous structure). The twisting process of the electrode fibers can be made until forming 1 to 6000 twists / m.

Thereafter, the method may further include the step of fixing the structure formed by curing the prepared electrode fibers in sufficient time, preferably for 24 to 60 hours in an environment of 0 to 10 ° C. Preferably for 48 hours in an environment at 4 ° C.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. It will be apparent to those skilled in the art, however, that these examples are provided to further illustrate the present invention, and the scope of the present invention is not limited thereto.

Example

Substrate and material used

As the enzyme for the anode, glucose oxidase (hereinafter referred to as GOx) extracted from aspergillus niger (219 U / mg) purchased from Amano Enzyme was used. GOx-dissolved buffer solution was purified and desalted using HiTrap QFF chromatography column (GE Healthcare Bio-Sciences AB, Sephadex G-25, PD 10, fast protein liquid chromatography (FPLC)). It was. As the cathode enzyme, bilirubin oxidase (hereinafter referred to as BOD) derived from myrothecium verrucaria (10.5 U / mg, Sigma Aldrich) was used without purification. Poly (ethylene glycol) diglycidyl ether (PEGDGE) purchased from Polysciences was used as a crosslinking agent, and as a redox electron mediator, poly (N-vinylimidazole)-[Os (4,4′-dimethoxy-2,2 ′ -Bipyridine) ₂ Cl]) ^{+ / 2 +} for anode, poly (N-vinylimidazole)-[Os (4,4′-dimethoxy-2,2′-bipyridine) ₂ Cl]) ^{+ / 2 +} Used for cathode.

Multi-containing enzyme Scrolled ( multi - scrolled ) Fabrication of Electrode Fiber

Solid-walled multi-walled carbon nanotube (MWNT) sheets were extracted from one wall of the MWNT forest, and vapor-phase polymerization (VPP) was applied to the MWNT sheets. Poly (3,4-ethylenedioxythiophene) (PEDOT) was coated. In the same process, a total of two individuals were made for the anode and the cathode.

Hereinafter, the PEDOT coated MWNT sheet is collectively referred to as PEDOT / MWNT.

A catalyst solution for the anode or the cathode was prepared by mixing the enzyme for the anode or the cathode, the redox electron mediator, and the crosslinking agent. More specifically, the catalyst solution for the anode comprises 41% by weight of GOx, 52% by weight of (poly (N-vinylimidazole)-[Os (4,4'-dimethoxy-2,2'-bipyridine ) ₂ Cl]) ^{+ / 2 +} , 7% by weight of poly (ethylene glycol) diglycidyl ether was mixed and the catalyst solution for the cathode was 41% by weight of BOD, 53% by weight of (poly (acrylic acid) -Poly (N-vinylimidazole)-[Os (4,4'-dichloro-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} , 5% by weight of poly (ethylene glycol as crosslinker Diglycidyl ether was prepared by mixing. In the catalyst solution for the cathode or anode thus prepared, the structure and electrical activity of the redox electron mediator are shown in FIG. 1 (FIGS. 1A and 1C: for anode, FIGS. 1B and 1D for cathode).

Next, two previously prepared PEDOT / MWNT sheets containing 85% by weight of PEDOT were immersed in the anode catalyst solution and the cathode catalyst solution, respectively. Thereafter, the materials in the catalyst solution were adsorbed uniformly on both sides of the PEDOT / MWNT sheet for 24 hours in an environment of 4 ° C.

Next, the PEDOT / MWNT sheet contained in the catalyst solution has 6000 revolutions per meter in the range of 50-300 rpm using a low-rpm motor. Twisting was imparted by rotation, and then cured for 48 hours in an environment at 4 ° C. to prepare a fibrous anode (Example 1) and cathode (Example 2) electrodes including warping. The length of Example 1 was 4.0 mm, the diameter was 60 µm, the length of Example 2 was 4.8 mm, and the diameter was 50 µm. The active surface areas of Example 1 and Example 2 were calculated to be 0.75 mm ² , respectively.

Test Example

Settings for Testing Electrochemical Properties

To test the electrochemical properties, one end of the electrode fibers prepared in the examples was bound to copper wire using a conventional silver paste (ELCOAT P-100), and the silver paste was isolated and dried with an epoxy adhesive. .

Anode (working electrode) according to Example 1, cathode (working electrode) according to Example 2, Ag / AgCl reference electrode, Pt to perform cyclic voltametry and chronoamperometry A three-electrode BFC comprising a network as a counter electrode was constructed (hereinafter referred to as Example 3), which was connected to a CHI 600B constant potentiometer.

Measurements were made at a 500 rpm setting in a 50 mL PBS (20 mM phosphate, 0.14 M NaCl, pH 7.4) buffer environment, at 37 ° C. ambient temperature. According to each test example, each of oxygen and atmospheric gas was passed through PBS for 30 minutes using a bubble generator to saturate them in a buffer solution.

Electricity measurements were made at a rate of 5 mV / s.

Observation of the properties of electrode fibers

The structures of Examples 1 and 2 were observed through scanning electron microscopy (SEM). The twisting process generally results in a dual-Archimedean internal scroll structure. The SEM image shown in FIG. 2 shows that the embodiments have the shape of warped fibers, with a porous surface (FIGS. 2B, 2C).

2D and 2E show cross-sectional views of the embodiment. As shown, the embodiment includes a multi-layered structure that is repeatedly stacked, and these layers each include PEDOT / MWNT and catalytic material, which structure facilitates fuel material delivery of BFCs including glucose and oxygen. . With this structure, the mechanical strength of the example was measured at a high level of 106.6 ± 8.2 MPa, while containing 88.1 ± 0.6 wt% of the catalyst material that was likely to drop in strength (Figure 3).

Anode , Cathode , BFC Performance and power density measurements

The inventors have calculated the ratio of redox electron mediator and enzyme to derive optimal anode-cathode performance. The performance (current density) as a biofuel cell is particularly affected by the mass% of BOD enzyme in the cathode. 4 shows a graph of measuring the current density change of the BFC according to the component ratio (10 to 70 mass%) of the BOD in the cathode. As shown, the current density is proportional to the mass% of the BOD in the cathode, and reaches a peak when the BOD reaches 35 to 45 mass%, and the current density rapidly decreases above that point.

To further find the optimum operating environment, the buffer solution environment was set as a variable and the current density was measured. As the glucose content of the anode increased (0 to 60 mM), the current density of the anode, Example 1, increased to 25.3 mA / cm ² (FIG. 5A). No further increase in current density was observed in cases above 60 mM, presumably because the GOx enzyme has a behavior corresponding to the Michaelis-menten type. In addition, the peak of the current density of the anode of Example 1 in the oxygen-saturated buffer solution environment was formed at 17.7 mA / cm ² , which was observed to be lower than that of saturating the atmospheric gas (25.3 mA / cm ² ) (FIG. 5B). This is because GOx reacted sideways with oxygen to produce hydrogen peroxide.

The results of testing the performance of the cathode of Example 2 is shown in FIG. 5C. As shown, the current density from the cathode peaks at 3.4 mA / cm ^{2 in} an atmosphere saturated buffer solution environment, and the cathode current density peaks at 5.7 mA / cm ^{2 in} an oxygen saturated buffer solution environment. To form. In addition, a two-electrode BFC (Example 4) comprising Example 1 as an anode and Example 2 as a cathode (hereinafter referred to as Example 4) was driven in an oxygen saturation buffer solution having a glucose concentration of about 60 mM, Open-circuit voltage is shown.

The values of the current density obtained in the present invention are very high compared to conventional methods using enzymes of the same or higher activity. As shown in FIG. 5D, Example 4 of the present invention provides a maximum power density of 2.31 mW / cm ² (= 840 mW / cm ³ , operating voltage of 0.4 V) in an oxygen-saturated buffer solution at a 60 mM glucose concentration. The maximum power density of 1.65 mW / cm ² (operating voltage 0.4 V) in an air-saturated buffer solution at a concentration of 60 mM glucose is shown. This BFC performance is remarkably improved. As a comparative example, BFCs prepared by the prior art (F. Gao, L. Viry, M. Maugey, P. Poulin, N. Mano, Engineering hybrid nanotube wires for high-power biofuel cells, Nature Communications. 1 (2010) 1-7.), Wherein the maximum power density performance (2.31 mW / cm ² ) implemented by Example 4 of the present invention is about three times that of the comparative example tested in the same environment.

In particular, the power output relative to the volume of Example 4 is 840 mW / cm ³ , and the power output to mass represents 191 mW / g, which corresponds to 506 times and 103 times, respectively (A. Zebda, C. Gondran, A. Le Goff, M. Holzinger, P. Cinquin, S. Cosnier, Mediatorless high-power glucose biofuel cells based on compressed carbon nanotube-enzyme electrodes., Nature Communications. 2 (2011) 370.).

That is, the electrode fiber according to the embodiment of the present invention has excellent wettability, electronic conductivity, and mechanical properties by coating PEDOT, a conductive polymer, on an MWNT sheet having a highly aligned molecular structure and exhibiting high electron mobility. In addition, the PEDOT layer coated on each surface of the nanotubes provides a porous structure to firmly fix the catalyst materials in three dimensions, thereby further catalyzing chemical reactions including current flow and enzyme activity (FIG. 6). ). Anodes, cathodes, and BFCs according to embodiments of the present invention exhibit significantly better performance than before, due to the specific three-dimensional hierarchical micro-structure implemented through the present invention. The twisting process carried out in accordance with the present invention also provides a laminated multi-layer internal structure to the electrode fibers. This structure greatly promotes the fixation and activity of enzymes at the anode or cathode, thus greatly improving the performance of BFCs comprising them. This means that the structure of the electrode fibers implemented according to one embodiment of the present invention accelerates the diffusion of the substrate (fuel) in the buffer solution.

The electrode fiber according to the present invention is summarized as follows.

1) Carbon carriers of porous and multilayer structure (PEDOT / MWNT in the examples) provide high active surface area.

2) The multi-twist structure formed through the twisting process further increases the amount of catalytically active material loaded into the porous structure. Thus, large amounts of enzyme directly increase current and current production.

3) The twisting process imparts a compression stress inside the electrode fibers, so that the more closely catalytically active material has very good electrical connectivity and good electron mobility.

With these factors promoting charge transfer between the catalyst material and the carrier, the performance of the electrode fibers according to the invention is dramatically improved. In addition, the electrode fibers according to the present invention do not require additional carriers for operation, and thus have better output density relative to volume or mass.

Measurement of stability of electrode fibers

Stability was measured by running the BFC of Example 4 continuously for 12 hours. A chronoamperometric method in which the cathode was connected to the working electrode was carried out, and the current generated from the BFC was measured over time at a constant voltage. The results observed in a fixed voltage of 0.4 V, PBS solution environment, temperature conditions of 37 ℃ is shown in Figure 7a. After the development of the BFC had stabilized, the BFC was run continuously for 12 hours, after which about 90% of the generation performance was achieved.

Application example  : In the form of a needle containing electrode fibers BFC

Figure 7c shows a double helix type BFC comprising electrode fibers according to the present invention. The cathode and anode electrodes surround the needles, which do not overlap and are therefore driven independently of each other in one system. In addition, the needle-type structure is a structure that is easy to be implanted in the human body.

Application example  : With electrode fiber Weave  Electrode fabric

Figure 7d shows an image of an electrode fabric woven with electrode fibers according to the present invention. Electrode fibers of 50 μm in diameter were used for this, and the size of the woven fabric was 5 mm × 7 mm. The scale bar in the right picture of FIG. 7D showing the fabric's detailed structure is 500 μm. As shown in FIG. 7B, the electrode fabric BFC thus produced exhibits a power of about 74 μW and an open circuit voltage of 0.77 V (black graph), with the power and voltage being applied in series with the two electrode fabrics. All showed a proportional increase that was doubled (148 μW and 1.54 V) (red graph).

As discussed in the above applications, the electrode fiber according to the present invention will be said to be infinite in the scope of application due to the freedom of configuration, and can be implemented not only as an ultra-small electrode device but also provide a significant performance improvement in the future. It is also expected to be made from a human-transplantable device, including needles, catheters and stents, or to medical electronics and nanorobots.

Claims (15)

Carbon nanotube sheet coated with a conductive polymer; And a functional particle adsorbed on the carbon nanotube sheet, wherein the electrode fiber has a multilayer structure. The method of claim 1,
The electrode fiber is in the form of a yarn made by twisting the carbon nanotube sheet, the multilayer structure is an electrode fiber, characterized in that formed in the process of twisting the carbon nanotube sheet in the form of a yarn. The method of claim 1,
Wherein the conductive polymer is selected from poly (3,4-ethylenedioxythiophene), polyaniline, polypyrrole, polyethylene, and polythiophene. The method of claim 1,
The adsorbed functional particles are electrode fibers, characterized in that at least one selected from enzymes capable of redox. The method of claim 1,
The electrode fiber further comprises an osmium (Os) -based redox mediator (redox mediator). The method of claim 5,
The redox electron mediator is (poly (N-vinylimidazole)-[Os (4,4'-dimethoxy-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} and (poly (acrylic acid) ) -Poly (N-vinylimidazole)-[Os (4,4'-dichloro-2,2'-bipyridine) ₂ Cl]) at least one electrode selected from ^{+ / 2 +} fiber. The method of claim 1,
The electrode fiber is an electrode fiber, characterized in that it comprises an oxidation electrode and a reduction electrode at the same time integrally. An electrode fabric comprising the electrode fibers according to claim 1. A biofuel cell comprising the electrode fiber according to any one of claims 1 to 7. A bioelectrode comprising the electrode fiber according to any one of claims 1 to 7,
The bioelectrode may be implantable into a living body as any one selected from a needle, a catheter, and a stent. a) preparing a carbon nanotube sheet and coating a conductive polymer on the carbon nanotube sheet;
b) immersing the carbon nanotube sheet coated with the conductive polymer in a mixed solution including an enzyme, a redox electron mediator and a crosslinking agent, and then adsorbing the enzyme and the redox electronic mediator on the carbon nanotube sheet; And
c) twisting the carbon nanotube sheet to produce electrode fibers having a multilayer structure. 12. The method of claim 11,
In step a), the prepared carbon nanotube sheet is a high density carbon nanotube sheet formed by evaporating alcohol from a carbon nanotube airgel sheet,
The conductive polymer is a method of manufacturing an electrode fiber, characterized in that the coating on the carbon nanotube sheet through vapor-phase polymerization (vapor-phase polymerization). 12. The method of claim 11,
The conductive polymer is a method of producing an electrode fiber, characterized in that selected from poly (3,4-ethylenedioxythiophene), polyaniline, polypyrrole, polyethylene and polythiophene. 12. The method of claim 11,
The mixed solution of step b) is at least one enzyme selected from glucose oxidase and bilirubin (bilirubin) oxidase;
(Poly (N-vinylimidazole)-[Os (4,4'-dimethoxy-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} and (poly (acrylic acid) -poly (N- At least one redox electron mediator selected from vinylimidazole)-[Os (4,4'-dichloro-2,2'-bipyridine) ₂ Cl]) ^{+ / 2 +} ; And
Poly (ethylene glycol) diglycidyl ether crosslinking agent; manufacturing method of the electrode fiber comprising a. 12. The method of claim 11,
In the step c), the carbon nanotube sheet is twisted (twist) and manufactured in a yarn form, and a method of manufacturing an electrode fiber, wherein a multilayered structure is formed in the process of twisting into a yarn form.

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