The Experts below are selected from a list of 2976 Experts worldwide ranked by ideXlab platform

Serge Cosnier - One of the best experts on this subject based on the ideXlab platform.

M. Fontecave - One of the best experts on this subject based on the ideXlab platform.

  • A synthetic redox biofilm made from metalloprotein–prion domain chimera nanowires
    Nature Chemistry, 2017
    Co-Authors: Lucie Altamura, Christophe Horvath, Saravanan Rengaraj, Anaelle Rongier, Kamal Elouarzaki, Chantal Gondran, Anthony L.b. Macon, Charlotte Vendrely, Vincent Bouchiat, M. Fontecave
    Abstract:

    Engineering bioelectronic components and set-ups that mimic natural systems is extremely challenging. Here we report the design of a protein-only redox film inspired by the architecture of bacterial electroactive biofilms. The nanowire scaffold is formed using a chimeric protein that results from the attachment of a prion domain to a rubredoxin (Rd) that acts as an electron carrier. The prion domain self-assembles into stable fibres and provides a suitable arrangement of redox metal centres in Rd to permit electron transport. This results in highly organized films, able to transport electrons over several micrometres through a network of bionanowires. We demonstrate that our bionanowires can be used as electron-transfer mediators to build a Bioelectrode for the electrocatalytic oxygen reduction by laccase. This approach opens opportunities for the engineering of protein-only electron mediators (with tunable redox potentials and optimized interactions with enzymes) and applications in the field of protein-only Bioelectrodes.

  • A Poly(amphiphilic pyrrole)-Flavin Reductase Electrode for Amperometric Determination of Flavins.
    Analytical Chemistry, 1997
    Co-Authors: S Cosnier, M. Fontecave, D Limosin, V Nivière
    Abstract:

    The electropolymerization of a flavin reductase-amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides the efficient entrapment of the enzyme in a functionalized polypyrrole film. The enzyme film was characterized and applied to the detection of several flavins and pyridine nucleotides. The response of the Bioelectrode was based on the amperometric oxidation, at -0.1 V vs SCE, of the enzymically generated dihydroflavins in the presence of reduced pyridine nucleotides. The highest sensitivities and detection limits were 668 mA M(-1) cm(-2) and 4 nM for riboflavin, 179 mA M(-1) cm(-2) and 20 nM for flavin mononucleotide, and 107 mA M(-1) cm(-2) and 40 nM for flavin adenine dinucleotide. Direct electrochemical measurements at -0.65 V and electroenzymatic measurements at -0.1 V of riboflavin, carried out with these Bioelectrodes, show that an amplification phenomenon occurs, due to an electrochemical recycling reaction of enzyme substrate. A nonamplified response to reduced pyridine nucleotides was also obtained in the presence of 0.1 mM riboflavin. The sensitivity and detection limit of the Bioelectrode are 19.6 mA M(-1) cm(-2) and 0.2 μM for NADH and 11.2 mA M(-1) cm(-2) and 0.5 μM for NADPH.

  • An original electroenzymatic system: Flavin reductase-riboflavin for the improvement of dehydrogenase-based biosensors. Application to the amperometric detection of lactate
    Electroanalysis, 1997
    Co-Authors: S Cosnier, Christophe Innocent, M. Fontecave, V Nivière
    Abstract:

    The electropolymerization of a flavin reductase (Fre) - amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides an efficient Bioelectrode for the amperometric detection of NADH and NADPH. The Bioelectrode response was based on the oxidation at -0.1 V vs. SCE of the enzymically generated dihydroriboflavin. The sensitivity and detection limit of the Bioelectrode were 29 mAM-' cm-' and 0.2pM for NADH and €5.8mAM-' cm-' and 0.4pM for NADPH. The coimmobilization of Fre and a lactate dehydrogenase leads to a dehydrogenase-based biozlectrode for the determination of lactate in the presence of riboflavin and NAD'. With laponite additives into the polypyrrole host matrix, the sensitivity and the detection limit of the Bioelectrode for lactate are 11.7 m.4M-I cm? and 1 pM respectively. Owing to the negative value of the applied potential for the oxidation of riboflavin, the response of the bienzyme electrode remains insensitive to interferents like ascorbate, urate and acetaminophen.

  • An original electroenzymatic system: Flavin reductase-riboflavin for the improvement of dehydrogenase-based biosensors. Application to the amperometric detection of lactate
    Electroanalysis, 1997
    Co-Authors: S Cosnier, Christophe Innocent, M. Fontecave, V Nivière
    Abstract:

    The electropolymerization of a flavin reductase (Fre) – amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides an efficient Bioelectrode for the amperometric detection of NADH and NADPH. The Bioelectrode response was based on the oxidation at −;0.1 V vs. SCE of the enzymically generated dihydroriboflavin. The sensitivity and detection limit of the Bioelectrode were 29 mAM−1 cm−2 and 0.2 μM for NADH and 15.8 mAM−1 cm−2 and 0.4 μM for NADPH. The coimmobilization of Fre and a lactate dehydrogenase leads to a dehydrogenase-based Bioelectrode for the determination of lactate in the presence of riboflavin and NAD+. With laponite additives into the polypyrrole host matrix, the sensitivity and the detection limit of the Bioelectrode for lactate are 11.7 mAM−1 cm−2 and 1 μM respectively. Owing to the negative value of the applied potential for the oxidation of riboflavin, the response of the bienzyme electrode remains insensitive to interferents like ascorbate, urate and acetaminophen.

V Nivière - One of the best experts on this subject based on the ideXlab platform.

  • A Poly(amphiphilic pyrrole)-Flavin Reductase Electrode for Amperometric Determination of Flavins.
    Analytical Chemistry, 1997
    Co-Authors: S Cosnier, M. Fontecave, D Limosin, V Nivière
    Abstract:

    The electropolymerization of a flavin reductase-amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides the efficient entrapment of the enzyme in a functionalized polypyrrole film. The enzyme film was characterized and applied to the detection of several flavins and pyridine nucleotides. The response of the Bioelectrode was based on the amperometric oxidation, at -0.1 V vs SCE, of the enzymically generated dihydroflavins in the presence of reduced pyridine nucleotides. The highest sensitivities and detection limits were 668 mA M(-1) cm(-2) and 4 nM for riboflavin, 179 mA M(-1) cm(-2) and 20 nM for flavin mononucleotide, and 107 mA M(-1) cm(-2) and 40 nM for flavin adenine dinucleotide. Direct electrochemical measurements at -0.65 V and electroenzymatic measurements at -0.1 V of riboflavin, carried out with these Bioelectrodes, show that an amplification phenomenon occurs, due to an electrochemical recycling reaction of enzyme substrate. A nonamplified response to reduced pyridine nucleotides was also obtained in the presence of 0.1 mM riboflavin. The sensitivity and detection limit of the Bioelectrode are 19.6 mA M(-1) cm(-2) and 0.2 μM for NADH and 11.2 mA M(-1) cm(-2) and 0.5 μM for NADPH.

  • An original electroenzymatic system: Flavin reductase-riboflavin for the improvement of dehydrogenase-based biosensors. Application to the amperometric detection of lactate
    Electroanalysis, 1997
    Co-Authors: S Cosnier, Christophe Innocent, M. Fontecave, V Nivière
    Abstract:

    The electropolymerization of a flavin reductase (Fre) - amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides an efficient Bioelectrode for the amperometric detection of NADH and NADPH. The Bioelectrode response was based on the oxidation at -0.1 V vs. SCE of the enzymically generated dihydroriboflavin. The sensitivity and detection limit of the Bioelectrode were 29 mAM-' cm-' and 0.2pM for NADH and €5.8mAM-' cm-' and 0.4pM for NADPH. The coimmobilization of Fre and a lactate dehydrogenase leads to a dehydrogenase-based biozlectrode for the determination of lactate in the presence of riboflavin and NAD'. With laponite additives into the polypyrrole host matrix, the sensitivity and the detection limit of the Bioelectrode for lactate are 11.7 m.4M-I cm? and 1 pM respectively. Owing to the negative value of the applied potential for the oxidation of riboflavin, the response of the bienzyme electrode remains insensitive to interferents like ascorbate, urate and acetaminophen.

  • An original electroenzymatic system: Flavin reductase-riboflavin for the improvement of dehydrogenase-based biosensors. Application to the amperometric detection of lactate
    Electroanalysis, 1997
    Co-Authors: S Cosnier, Christophe Innocent, M. Fontecave, V Nivière
    Abstract:

    The electropolymerization of a flavin reductase (Fre) – amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides an efficient Bioelectrode for the amperometric detection of NADH and NADPH. The Bioelectrode response was based on the oxidation at −;0.1 V vs. SCE of the enzymically generated dihydroriboflavin. The sensitivity and detection limit of the Bioelectrode were 29 mAM−1 cm−2 and 0.2 μM for NADH and 15.8 mAM−1 cm−2 and 0.4 μM for NADPH. The coimmobilization of Fre and a lactate dehydrogenase leads to a dehydrogenase-based Bioelectrode for the determination of lactate in the presence of riboflavin and NAD+. With laponite additives into the polypyrrole host matrix, the sensitivity and the detection limit of the Bioelectrode for lactate are 11.7 mAM−1 cm−2 and 1 μM respectively. Owing to the negative value of the applied potential for the oxidation of riboflavin, the response of the bienzyme electrode remains insensitive to interferents like ascorbate, urate and acetaminophen.

Wei Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Fabrication and characteristic of flexible dry Bioelectrodes with microstructures inspired by golden margined century plant leaf
    Sensors and Actuators A: Physical, 2021
    Co-Authors: Wei Zhou, Chengzhong Liu, Da Geng, Dai Jishen, Chen Songyue, Tao Luo, Zheng Shen
    Abstract:

    Abstract To obtain a flexible dry Bioelectrode with high performance, this paper proposes a flexible dry Bioelectrode with microneedle structures inspired by golden margined century plant leaf. The microneedle structures are fabricated by laser processing method, and then embedded inside the flexible PDMS substrate. In this way, the flexible dry Bioelectrode with curved-hook type microneedle structures is obtained. The mechanical and electrical properties of the Bioelectrode are characterized. Our results show that the curved-hook type microneedle has a smaller penetration force (0.939 N) but bigger pullout force (0.149 N) compared with triangular microneedles. The curved-hook type microneedle structures allow better anti-destructive and bonding performance. Additionally, compared with traditional Ag/AgCl electrode, the developed flexible dry Bioelectrodes exhibit better detection performance of EMG in both time and frequency domain.

  • Impedance and electromyographic properties of metal dry Bioelectrode with non-uniform surface microstructure
    Applied Physics A, 2018
    Co-Authors: Wei Zhou, Shaoyu Liu, Chenying Zhang, Haotian She, Jinying Zhu
    Abstract:

    To develop a Bioelectrode with excellent electrical performance, laser micromachining was proposed to fabricate a metal dry Bioelectrode with a non-uniform surface microstructure. By controlling the scanning path, scanning times, and output power, metal dry Bioelectrodes with different types of surface microstructure distribution (uniform and non-uniform) were obtained. Compared with traditional Ag/AgCl wet electrode, the influence of the surface microstructure distribution on the impedance and electromyographic properties of metal dry Bioelectrodes was investigated. Results show that the surface microstructure distribution has little influence on the impedance properties of the Bioelectrode within the testing time and frequency domains. However, the electromyographic properties of metal dry Bioelectrodes with uniform and non-uniform surface microstructures were better than that of conventional Ag/AgCl wet electrodes. The strongest electromyographic signal was obtained using a metal dry Bioelectrode with non-uniform surface microstructure.

  • Electrical impedance performance of metal dry Bioelectrode with different surface coatings
    Sensors and Actuators A: Physical, 2018
    Co-Authors: Wei Liu, Wei Zhou, Shaoyu Liu, Chenying Zhang, Shuaishuai Huang, Kwan San Hui
    Abstract:

    To improve the electrical impedance performance of Bioelectrodes, a novel metal dry Bioelectrodes with different coating layers are developed with laser micromilling and electroplating technology. Based on the analysis of the coating layer on the Bioelectrode surface, the effect of different coating layers on the electrical impedance performance of Bioelectrodes is investigated. The results show that the silver content increases with electroplating time when the silver layer is coated on the Bioelectrode surface. However, the decrease of silver layer weight is observed with much longer electroplating time, and the optimal electroplating time is 20 min. Compared with the uncoated Bioelectrode, the Bioelectrode coated with silver layer exhibits much lower impedance value and better impedance stability. Especially, when the silver-coated Bioelectrode is subsequently coated with silver-silver chloride layer, the lowest impedance value and best impedance stability are obtained.

  • Mechanical properties of surface microstructures of metal dry Bioelectrode
    Sensors and Actuators A: Physical, 2018
    Co-Authors: Wei Zhou, Shaoyu Liu, Chenying Zhang, Haotian She, Jinying Zhu
    Abstract:

    Abstract The metal dry Bioelectrodes have been developed to measure the bioelectrical signals. In this study, the laser micromilling process as an economical and high efficiency way was proposed to fabricate the metal dry Bioelectrodes with surface microstructure array. The measuring principle of material hardness was adopted to characterize the mechanical properties of surface microstructures of metal dry Bioelectrodes. Moreover, the compressive strength of surface microstructures of metal dry Bioelectrodes fabricated with different scan spacings was discussed, and then the bending strength and insertion performance of surface microstructures of metal dry Bioelectrodes were further investigated. The results show that surface microstructures of Bioelectrode fabricated using three scan spacings including 100 μm, 150 μm and 200 μm exhibited better compressive performance. When the 100 μm scan spacing was selected, the surface microstructures of metal dry Bioelectrodes presented larger bending strength, and it could successfully penetrate the silicon film with a small pressure about 1.48 N.

  • Characterization of impedance properties of metal dry Bioelectrodes with surface microstructure arrays
    Sensors and Actuators A: Physical, 2017
    Co-Authors: Wei Zhou, Wei Liu, Shaoyu Liu, Chenying Zhang, Zhijia Shen, Guobiao Zhang
    Abstract:

    Abstract A metal dry Bioelectrode with surface microstructure arrays is fabricated using the laser direct micromilling technology with advantages of high efficiency and low cost. The impedance properties of the metal dry Bioelectrode are then analyzed using the two-electrode measurement method. The equivalent circuit of the electrode-skin contact model has been developed, and the influences of current frequency, electrode size, laser power and contact pressure on the impedance properties are investigated. The results show that the impedance of the Bioelectrode decreases with increasing electrode diameter in the range of 6–10 mm. With increasing laser power, the impedance of the Bioelectrode tends to decrease gradually. When a contact pressure is applied on the Bioelectrode surface, its impedance drastically decreases. Compared with the traditional silver/silver chloride (Ag/AgCl) electrode, the impedance of the Bioelectrode shows good stability. Due to the advantages of convenient, repeatable use, without the removal of the stratum corneum (the outermost layer of the skin), the developed metal dry Bioelectrode has broad prospects in the collection and application of bioelectrical signals.

Chantal Gondran - One of the best experts on this subject based on the ideXlab platform.

  • a synthetic redox biofilm made from metalloprotein prion domain chimera nanowires
    Nature Chemistry, 2017
    Co-Authors: Lucie Altamura, Christophe Horvath, Saravanan Rengaraj, Anaelle Rongier, Kamal Elouarzaki, Chantal Gondran
    Abstract:

    Engineering bioelectronic components and set-ups that mimic natural systems is extremely challenging. Here we report the design of a protein-only redox film inspired by the architecture of bacterial electroactive biofilms. The nanowire scaffold is formed using a chimeric protein that results from the attachment of a prion domain to a rubredoxin (Rd) that acts as an electron carrier. The prion domain self-assembles into stable fibres and provides a suitable arrangement of redox metal centres in Rd to permit electron transport. This results in highly organized films, able to transport electrons over several micrometres through a network of bionanowires. We demonstrate that our bionanowires can be used as electron-transfer mediators to build a Bioelectrode for the electrocatalytic oxygen reduction by laccase. This approach opens opportunities for the engineering of protein-only electron mediators (with tunable redox potentials and optimized interactions with enzymes) and applications in the field of protein-only Bioelectrodes.

  • A synthetic redox biofilm made from metalloprotein–prion domain chimera nanowires
    Nature Chemistry, 2017
    Co-Authors: Lucie Altamura, Christophe Horvath, Saravanan Rengaraj, Anaelle Rongier, Kamal Elouarzaki, Chantal Gondran, Anthony L.b. Macon, Charlotte Vendrely, Vincent Bouchiat, M. Fontecave
    Abstract:

    Engineering bioelectronic components and set-ups that mimic natural systems is extremely challenging. Here we report the design of a protein-only redox film inspired by the architecture of bacterial electroactive biofilms. The nanowire scaffold is formed using a chimeric protein that results from the attachment of a prion domain to a rubredoxin (Rd) that acts as an electron carrier. The prion domain self-assembles into stable fibres and provides a suitable arrangement of redox metal centres in Rd to permit electron transport. This results in highly organized films, able to transport electrons over several micrometres through a network of bionanowires. We demonstrate that our bionanowires can be used as electron-transfer mediators to build a Bioelectrode for the electrocatalytic oxygen reduction by laccase. This approach opens opportunities for the engineering of protein-only electron mediators (with tunable redox potentials and optimized interactions with enzymes) and applications in the field of protein-only Bioelectrodes.