Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/20—Carbon compounds, e.g. carbon nanotubes or fullerenes
  • H10K85/221—Carbon nanotubes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/761—Biomolecules or bio-macromolecules, e.g. proteins, chlorophyl, lipids or enzymes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having potential barriers
  • H10K10/80—Constructional details
  • H10K10/82—Electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2918—Rod, strand, filament or fiber including free carbon or carbide or therewith [not as steel]

Definitions

• the invention relates to electrically conductive fibers for bioelectrochemical systems.
• the invention also relates to electrodes made of such fibers and systems comprising one or more such electrodes.
• the invention applies to the production of bioelectrochemical systems, in particular biomedical systems such as, for example, enzymatic, immunological, DNA, RNA and biopile biosensors. State of the prior art.
• Carbon is a material of choice for the realization of electrodes. Its chemical inertia makes it possible to explore large ranges of potentials in electrochemistry. This is why carbon is very widely used in various forms for the realization of electrochemical devices: sensors, actuators, batteries and storage batteries. In addition, carbon has the particularity of being a material on which organic molecules and molecules are effectively adsorbed. It is therefore possible to absorb redox polymers, enzymes or conductive polymers for the production of advanced electrochemical devices, more efficient and selective. It is also biocompatible and ideally suited for producing devices for biological applications.
• Carbon has other interests that are mechanical strength, thermal stability and the possibility of use in the form of "fibers"("fiber” being defined as a system of indefinite length and diameter between 10 nanometers and 1 millimeter ). This possibility is extremely valuable for the miniaturization of devices, the realization of microelectrodes or implantable systems in living organisms. Fiber shaping is also useful because it is a means of increasing the accessible surface area for a given volume of material. In all electrochemical devices, the specific surface is critical because it conditions the amplitude of the responses of the devices. Given these various advantages, traditional carbon fibers have been widely studied for the realization of microelectrodes, sensors and electrochemical biopiles. They are still today the most used material for miniaturized biopiles and the production of microelectrodes.
• Increasing the current density of a biosensor or a biopile is an essential step in order to achieve sufficient detection limits or powers of the order of 2 ⁇ W respectively. To do this, it is necessary to increase the specific surface area of the electrodes.
• Carbon nanotubes are materials that have a priori very interesting characteristics for bio-electrochemistry. They are made of carbon and have a very large surface area due to their nanoscale size. However mass produced nanotubes are not structured. They are in the form of a powder that can not be used in the state for bioelectrochemical applications.
• enzymes are mixed in dispersion CNTs and the redox polymer is then added to form a sample which is placed on the surface of the glassy carbon bar to form an electrode.
• the electrodes formed according to the two techniques described are not made of an NTC fiber.
• the electrochemical processes on such electrodes are confined to the surface of the electrodes which limits the currents obtained.
• it results from the present invention an organization and orientation of CNTs at the nanoscale.
• the assembly in the form of fibers makes it possible to obtain a three-dimensional electrode which consequently increases the surface area compared with those of the state of the art.
• the biological compounds are provided on the nanotubes after they have been assembled in the form of fibers.
• the initial assembly of nanotubes in the form of a fiber makes it possible to maximize the effectiveness of the contacts between nanotubes and hence the conductivity of the electrode.
• This document relates to a functional nanoparticle comprising a conductive nanoparticle (metal) or semiconducting or in CNT, and a bi-functional protein.
• the described proteins have two activity domains, one of these domains is used to attach the protein to the nanotube.
• Applications are described for metallic or semiconducting nanoparticles.
• Such nanoparticles make it possible to nanoscale for electronic circuits, or assemblies forming networks with high integration of metal nanoparticles.
• no description concerning the realization of an electrically conductive fiber and the use of such a fiber to make an electrode is made or even suggested.
• the present invention aims to solve the problem of producing electrically conductive fibers for applications such as bioelectrochemical systems such as biosensors and biopiles used in particular in biomedical applications.
• bioactive fibers which have a high specific surface and a conductivity which makes it possible to obtain the detection limits or the powers required in bioelectrochemical systems such as biosensors or biopiles.
• the present invention more particularly relates to electrically conductive fibers mainly characterized in that they consist of assembled carbon nanotubes covered with a deposit comprising at least one biopolymer.
• the biopolymer may be chosen from natural or synthetic proteins such as, for example, enzymes.
• the deposit may further comprise one or more redox polymer (s) to improve the conductive properties of the fibers.
• the biopolymer may be chosen from nucleic acids, for example DNA or RNA.
• Another object of the invention relates to the method of manufacturing said fibers.
• This method comprises the steps of making fibers consisting of carbon nanotubes, and performing one or more deposition (s) on the fibers, one of which comprises at least one biopolymer.
• Deposition can be carried out by dipping or immersing the fibers in a solution containing at least one biopolymer or by deposition of the solution containing at least one biopolymer on the fibers or else by electrodeposition.
• the deposition for example by brushing or spraying, is particularly suitable in the case where one seeks to cover selected sections of fibers.
• the deposition on the fibers further comprises one or more redox polymer (s). This deposit is made at the same time as the deposition of the biopolymer (s) by the same technique as that used for the biopolymer.
• the deposition of the polymer (s) redox (s) can also be performed before the deposition of the biopolymer (s) by immersion technique or electroplating or deposition.
• the process for producing carbon nanotube fibers comprises spinning fibers obtained by coagulating the nanotubes from a dispersion of nanotubes in an aqueous or organic solvent.
• the process also comprises a step of removal of the binder before making the deposit.
• Removal of the binder involves heating the fibers to the binder decomposition temperature.
• the binder used is binder having a decomposition temperature does not exceed 700 0 C is chosen for example polyvinyl alcohol (PVA) and the heating of the fibers is preferably carried out under inert atmosphere and at a temperature which may be between 300 ° C. and 1100 ° C. and which is preferably chosen at 600 ° C.
• PVA polyvinyl alcohol
• the invention also relates to the production of fiber electrodes of carbon nanotubes as described above.
• Such electrodes consist of a section of fiber made of assembled carbon nanotubes covered with a deposit comprising at least one biopolymer according to the invention.
• the electrodes may consist of a fiber section of which only one end comprises the biopolymer deposit and optionally a redox polymer.
• the electrodes as defined above are particularly suitable for use in bioelectrochemical systems such as biopiles or biosensors.
• microelectrodes namely electrodes consisting of a fiber section with a length of less than 5 cm, for example 1 to 3 cm and 1 to 100 cm. micrometers in diameter.
• the improvement of these properties further allows the use of microelectrodes in biomedical systems that can be implanted in the human body.
• FIG. 1 represents the current density curves in the case of an electro-reduction of oxygen, for a conventional carbon fiber electrode and for an electrode according to the invention
• FIG. 2 represents the evolution curves over time of the electro-reduction of oxygen for a conventional carbon fiber and for a fiber according to the present invention
• FIG. 3 represents the diagram of a biopile equipped with electrodes according to the present invention
• FIG. 4 represents the diagram of a biosensor equipped with electrodes according to the present invention
• FIG. 5 shows the diagram of the steps of the fiber manufacturing process according to the invention.
• the electrically conductive fibers according to the present invention are fibers which have a very high specific surface area relative to the fibers of the state of the art, this specific surface is greater than 50 m 2 / g.
• Such fibers are obtained by manufacturing fibers consisting only of assembled carbon nanotubes: step bearing the reference 1 in FIG. 5 and then treating these fibers to render them bioelectroactive: step 3 in FIG.
• This treatment consists in covering them with a biopolymer chosen according to the different applications.
• the fibers obtained thus consist of assembled carbon nanotubes and a deposit comprising at least one biopolymer.
• the deposit may also comprise a polymer also called redox polymer.
• the biopolymer can be chosen from:
• Nucleic acids such as DNA, RNA.
• the fibers are for example obtained from the manufacturing method described in the patent application WO0163028.
• This method makes it possible to obtain fibers which consist solely of carbon nanotubes assembled and oriented at the macroscopic scale by coagulation of the nanotubes from a dispersion of nanotubes in an aqueous or organic solvent.
• the fibers obtained by this process comprise a binder which it is necessary to remove for the envisaged applications, that is to say bioelectrochemical applications.
• An advantage of this method is that it allows the manufacture of fibers from nanotubes mono, double or multi wall mass produced.
• nanotube fibers in the presence of polymeric binder developed according to the method described in this patent application WO0163028 are flexible enough to be folded and knotted without breaking, unlike traditional carbon fibers.
• binders which facilitate spinning during manufacture limits the specific surface area and the conductivity of the fibers, which is why it is necessary for the present invention to remove the binder in order to release the surface of the carbon nanotubes.
• the process for manufacturing the fibers according to the present invention thus comprises in this mode of embodiment, an additional step, step bearing the reference 2 in Figure 5, of removing the binder used and that by a high temperature treatment.
• the binder used in the manufacture of such fibers will be chosen so that it is easy to eliminate without the properties of the carbon nanotubes are degraded.
• polyvinyl alcohol (PVA) can be chosen.
• PVA polyvinyl alcohol
• This binder is a polymer that ensures good coagulation of the nanotubes in the spinning process. It can be degraded by a heat treatment from 300 ° C. This binder is degraded to more than 95% by a heat treatment at 600 ° C. in a non-oxidizing atmosphere. At this temperature the nanotubes are not degraded at all.
• the fibers consist exclusively of carbon nanotubes.
• the orientation of the nanotubes will be controlled by stretching carried out before the thermal annealing of the fibers. Stretches before annealing allow modulating and controlling their electrical conductivity as well as their diameter, density and capacitance.
• the fibers consisting solely of nanotubes have a very high specific surface area greater than 50 m 2 / g. they have a diameter of 1 to 100 microns and have a density of up to 1.8 g / cm3.
• the fiber manufacturing method according to the invention further comprises a treatment carried out in one or more steps, depending on the type of fibers, to adapt them to the bioelectrochemical properties.
• This treatment consists in covering the fibers with bioelectroactive (or biospecific) species, and more particularly, with one or more selected biopolymers. This step bears the reference 3 in FIG.
• the treatment for rendering the bioelectroactive fibers may, for example, consist in soaking the fibers in solutions containing the required species or species, that is to say the selected polymer (s), or immersing those with these solutions or by deposition of the solution on the fibers (for example by brushing or spraying them) or even by electroplating the solution on the fibers by applying a potential in the solution.
• the very strong interaction of the nanotubes with the polymers ensures an increased absorption stability.
• Absorption stability is critical for the stability of sensor or biopile systems.
• the fibers according to the invention thus guarantee a much longer operating time than that accessible by traditional carbonaceous materials.
• a second treatment is provided consisting in covering the fibers of the redox polymer adapted to the selected biopolymer.
• the deposition of the redox polymer (s) can be carried out at the same time as the deposition of the biopolymer or may have been done before and by the same techniques, immersion, electroplating, deposition.
• the method of Gao et al can be used: "Electrodeposition of Redox Polymers and Co-Electrodeposition of Enzymes" CoordinativeCrosslinking ", Zhiqiang Gao, Gary Binyamin, Kim Hyug-Han, Scott Calabrese Barton, Yongchao Zhang, and Adam Heller, Angew. Chem. Int. Ed. 2002, 41, No. 5, 810-813.
• the process for obtaining carbon nanotube fibers may, in an alternative embodiment, be carried out by coagulation without a polymeric binder according to the process described, for example, in the article by J. Steinmetz, M. Glerup, M. Paillet, P.
• This second embodiment may, for example be reserved for non-continuous production of fibers. Indeed, the spinning without polymeric binder is much more delicate and unsuitable for continuous production of homogeneous fibers and sufficient mechanical strength.
• the fibers according to the invention are biospecific and have a large specific surface, a high electrical conductivity, and an increased stability compared to the electrodes of the state of the art, they meet the needs encountered for the production of electrodes in systems bioelectrochemicals.
• FIGS. 1 and 2 The comparative results are illustrated in FIGS. 1 and 2, the results relating to the carbon fiber are shown in fine lines and those of the fiber according to the invention are represented in thick lines.
• an enzyme such as bilirubin oxidase and its polymer-redox PAA-PVI- [Os (4,4'-dichloro-2,2'-bipyridine) 2Cl] + / 2.
• the comparative measurements were carried out by carrying out an electro-reduction of 02 on a carbon fiber electrode (thin line) and on a nanotube fiber electrode according to the invention (thick line) under the following conditions: 20 mM phosphate buffer, 0.14 M NaCl, pH 7.2, 37.5 C, 1 mV.s-1.
• the composition of the bioelectrocatalyst used to cover the electrodes subject of the comparison 32% by weight of Bilirubin Oxidase, 60.5% by weight of PAA-PVI- [Os (4,4'-dichloro-2,2'-bipyridine) 2Cl] + / 2 +, 7.5% by weight of crosslinking agent (poly-ethylene glycol (400) diglycidyl ether).
• FIG. 2 illustrates the evolution over time of the electro-reduction of O 2 on the carbon fiber electrode (white circles) and on the carbon nanotube fiber electrode according to the invention (black circles) under the following conditions: a 20 mM phosphate buffer solution, 0.14 M NaCl, pH 7.2, 37.5 C, 1 mV.s-1. Composition of the bioelectrocatalyst: 32% by weight of Bilirubin Oxidase, 60.5% by weight of PAA-PVI-
• the anode and the cathode are electrodes obtained from carbon nanotube fibers as previously described. These electrodes consist of carbon nanotube fibers coated with their respective bioelectrocatalysts and reside in the same solution.
• the electrodes are connected to a component R and allow to supply a power supply to this component thanks to the following reactions:
• Equation 3 represents the overall reaction of the stack. ⁇ -D-glucose -> ⁇ -gluconolactone + 2H + + 2e- (1)
• a biopile as described can produce a few microwatts and can feed a biodevector-autonomous transmitter R, which records, for example , local glucose concentration, appropriate for diabetes management or local temperature, evidence of infection of an internal injury after surgery or microsurgery.
• the diagram of FIG. 4 illustrates the application of the invention to the production of a biosensor.
• the biosensor includes three electrodes, an anode El, E2 against an electrode and a reference electrode E ref.
• the anode El consists of carbon nanotube fibers comprising a deposit of bioelectrocatalyst ie biopolymer and the selected redox polymer. This anode resides in a solution of chemical species suitable for the measurement carried out.
• the cathode is the reference electrode E re f, that is to say the electrode brought to a fixed potential immersed in a buffer solution. If the same bioelectrocatalyst is used as in the example given for the reactions in FIG.
• the measurement of the potential of the anode relative to that of the cathode gives information on the presence and the quantity of glucose.
• the electrodes E1, E2 and E ref are connected to a component C of the sensor or detector type (potentiostat), which makes it possible to measure the current or voltage resulting from the bioelectrocatalysis.
• the fibers according to the invention find applications in all bioelectrochemical systems.
• the fibers according to the invention can be manufactured continuously. Their section may be circular or not, and the largest dimension of the section may be between 10 nm and 1 mm. Any type of nanotube is usable for their manufacture.
• Deposition of the biopolymer can be performed by dipping or soaking in a solution comprising the desired biopolymer (enzyme or DNA or RNA), or by electrodeposition, the electroplating being done in a known manner by applying an electrical potential to the solution.
• this redox polymer may be in the same solution as the biopolymer, the redox polymer is then deposited at the same time as the polymer or co-electrodeposited.
• concentrations of polymer and biopolymers can range from 0.1 mg / ml to 10 mg / ml and the thickness of the biopolymer deposition can range from a few angstroms to a few micrometers.
• the polymer concentrations are chosen so as to have a control of the thickness of the deposit and more precisely of the amount of deposited biopolymer.
• the production of electrodes from such fibers consists in cutting sections of fibers, to the length desired. Thus, any length can be arranged.
• Electrodes In most applications, and this is the case for the use of electrodes in the production of biopiles or biosensors, a very short length will be chosen, the lengths of said electrodes do not exceed, for example, 5 cm, 1 to 3 cm. preferably. They are microelectrodes from 1 to 30 micrometers in diameter and 1 to 3cm in length that can be implanted under the skin or in any living organism.
• Electrodes from these fibers consists in cutting sections of fiber so as to have the deposit (biopolymer and optionally redox polymer) only at one end of the section.
• Such electrodes can be used in the realization of neurobiological probes for example.
• the fibers described in the present invention can be used in the form of multifilament yarns and ribbons, mats, woven or nonwoven structures.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Nanotechnology (AREA)
• Physics & Mathematics (AREA)
• Mathematical Physics (AREA)
• Theoretical Computer Science (AREA)
• Crystallography & Structural Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biochemistry (AREA)
• Biophysics (AREA)
• General Health & Medical Sciences (AREA)
• Molecular Biology (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Carbon And Carbon Compounds (AREA)
• Artificial Filaments (AREA)
• Inorganic Fibers (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Conductive Materials (AREA)

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• 2008
  • 2008-06-13 FR FR0853918A patent/FR2932603B1/fr not_active Expired - Fee Related
• 2009
  • 2009-06-08 US US12/997,628 patent/US20110165458A1/en not_active Abandoned
  • 2009-06-08 EP EP09761925.8A patent/EP2351048B1/fr not_active Not-in-force
  • 2009-06-08 WO PCT/FR2009/051076 patent/WO2009150374A2/fr not_active Ceased
  • 2009-06-08 JP JP2011513031A patent/JP5635500B2/ja not_active Expired - Fee Related

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