Chantal Gondran

Mediatorless high-power glucose biofuel cells based on compressed carbon nanotube-enzyme electrodes

Enzymatic fuel cells use enzymes to produce energy from bioavailable substrates. However, such biofuel cells are limited by the difficult electrical wiring of enzymes to the electrode. Here we show the efficient wiring of enzymes in a conductive pure carbon nanotube matrix for the fabrication of a glucose biofuel cell (GBFC). Glucose oxidase and laccase were respectively incorporated in carbon nanotube disks by mechanical compression. The characterization of each bioelectrode shows an open circuit potential corresponding to the redox potential of the respective enzymes, and high current densities for glucose oxidation and oxygen reduction. The mediatorless GBFC delivers a high power density up to 1.3 mW cm−2 and an open circuit voltage of 0.95 V. Moreover, the GBFC remains stable for 1 month and delivers 1 mW cm−2 power density under physiological conditions (5×10−3 mol l−1 glucose, pH 7). To date, these values are the best performances obtained for a GBFC.

Single Glucose Biofuel Cells Implanted in Rats Power Electronic Devices

We describe the first implanted glucose biofuel cell (GBFC) that is capable of generating sufficient power from a mammals body fluids to act as the sole power source for electronic devices. This GBFC is based on carbon nanotube/enzyme electrodes, which utilize glucose oxidase for glucose oxidation and laccase for dioxygen reduction. The GBFC, implanted in the abdominal cavity of a rat, produces an average open-circuit voltage of 0.57 V. This implanted GBFC delivered a power output of 38.7 μW, which corresponded to a power density of 193.5 μW cm−2 and a volumetric power of 161 μW mL−1. We demonstrate that one single implanted enzymatic GBFC can power a light-emitting diode (LED), or a digital thermometer. In addition, no signs of rejection or inflammation were observed after 110 days implantation in the rat.

Electrogeneration of Biotinylated Functionalized Polypyrroles for the Simple Immobilization of Enzymes

A new biotin derivative functionalized by a pyrrole group has been synthesized. This functionalization has allowed the preparation of the first example of a poly(pyrrole-biotin) film by oxidative polymerization. In addition, the successful copolymerization of a polypyridinyl complex of ruthenium(II) containing pyrrole groups with the biotin derivative provided redox copolymers exhibiting specific adsorption sites. The resulting copolymer electrodes were applied to the immobilization of a biotinylated glucose oxidase through an avidin bridge. An avidin-conjugated alkaline phosphatase was also immobilized by direct specific adsorption onto the biotinylated polymer. The amperometric response of the resulting biosensors to glucose and phenylphosphate has been studied.

Label-free impedimetric thrombin sensor based on poly(pyrrole-nitrilotriacetic acid)-aptamer film

A label-free and highly sensitive impedimetric aptasensor was developed based on electropolymerized film for the determination of thrombin. The first step is the electrogeneration of a poly(pyrrole-nitrilotriacetic acid) (poly(pyrrole-NTA)) film onto the surface of electrodes followed by complexation of Cu(2+) ions. Then, the histidine labeled thrombin aptamer was immobilized onto the electrode through coordination of the histidine groups on the NTA-Cu(2+) complex. The aptamer sensor was applied for the detection and quantification of thrombin via impedimetric detection without a labeling step. A linear quantification of thrombin was obtained in the range 4.7×10(-12)-5.0×10(-10) mol L(-1) with a sensitivity of 2838 Ω/log unit (R(2)=0.9984). The impedance modulus at 0.3 Hz as a function of thrombin concentration was used to elaborate a similar linear relationship from 4.7×10(-12) to 5×10(-10) mol L(-1). In addition, aptamer-poly(pyrrole-NTA) electrodes incubated for 40 min in aqueous solutions of bovine serum albumin (BSA), lysozyme and IgG (5×10(-7) mol L(-1)) did not exhibit non-specific adsorption of proteins. Moreover, it has been demonstrated that the selective sensor can be regenerated several times with a good reproducibility.

Impedimetric immunosensor based on a polypyrrole-antibiotic model film for the label-free picomolar detection of ciprofloxacin.

This paper describes the construction of an impedimetric immunosensor for the label-free detection of ciprofloxacin, an antibiotic belonging to synthetic fluoroquinolones. A poly(pyrrole-N-hydroxysuccinimide) film was electrogenerated onto electrodes and then used for the reagentless covalent binding of a fluoroquinolone model bearing an amino group. The resulting electrodes were utilized to immobilize a layer of anticiprofloxacin antibody onto the polymer surface by immunoreaction. In presence of ciprofloxacin, the antibody was displaced in solution inducing marked changes in the impedance of the sensor electrodes. These phenomena were detected and characterized by electrochemical impedance spectroscopy allowing the selective detection of extremely low ciprofloxacin concentration, namely, 1 x 10(-12) g mL(-1) or 3 pmol L(-1). Sensors exposed to ciprofloxacin showed a decrease in the sum of the interfacial resistances with the increase in ciprofloxacin concentration from 1 x 10(-12) to 1 x 10(-6) g mL(-1).

Poly(pyrrole-metallodeuteroporphyrin)electrodes: towards electrochemical biomimetic devices

New Cu (II), Mn (III) and Fe (III) deuteroporphyrins functionalized by two electropolymerizable pyrrole groups have been synthesized. The electrooxidation of these metallodeuteroporphyrins has allowed the formation of conducting polypyrrole films exhibiting electrochemical behavior identical to that of the corresponding monomers. In addition, the efficient immobilization of metallodeuteroporphyrins was corroborated by spectrophotometric measurements. Moreover, the potential electrocatalytic properties of Mn (III)-based polypyrrole films in the presence of dioxygen and benzoic anhydride have been illustrated by cyclic voltammetry. Furthermore, the recognition properties of Fe (III)-based polypyrrole films have been highlighted with cyanide in organic electrolyte. Preliminary experiments have also demonstrated the feasibility of such recognition processes in aqueous media.

Electrogeneration of a biotinylated poly(pyrrole-ruthenium(II)) film for the construction of photoelectrochemical immunosensor

A biotinylated photosensitive polymer was electrogenerated from on a ruthenium complex bearing biotin and pyrrole groups; the resulting polypyrrolic film allowed the bioaffine immobilisation of avidin and biotinylated cholera toxin and the photoelectrochemical detection of the corresponding antibody.

Comparison between the performances of amperometric immunosensors for cholera antitoxin based on three enzyme markers.

We developed a novel copolymer modified amperometric immunosensor for the detection of cholera antitoxin (anti-CT), by the electropolymerization of pyrrole-biotin and pyrrole-lactitobionamide monomers on platinum or glassy carbon electrodes. In the detection of cholera antitoxin we have used three enzymatic marker detection systems based on HRP-labeled rabbit IgG antibodies, biotinylated polyphenol-oxidase (PPO-B) and biotinylated glucose-oxidase (GOX-B). The comparison of the electro-enzymatic performances of these three configurations with different substrates, clearly shows that the more sensitive amperometric immunosensor was based on HRP with a lower limit of detection of 50ng/ml anti-CT using hydroquinone/H(2)O(2) system. The response time for this substrate was in range of 5-30s. The HRP-amperometric immunosensor has thus proven to be a very sensitive tool to monitor nanomolar concentrations of anti-CT.

Tethered bilayer lipid membranes on mixed self-assembled monolayers of a novel anchoring thiol: impact of the anchoring thiol density on bilayer formation.

Tethered bilayer lipid membranes (tBLMs) are designed on mixed self-assembled monolayers (SAMs) of a novel synthetic anchoring thiol, 2,3-di-o-palmitoylglycerol-1-tetraethylene glycol mercaptopropanoic acid ester (TEG-DP), and a new short dilution thiol molecule, tetraethylene glycol mercaptopropanoic acid ester (TEG). tBLM formation was accomplished by self-directed fusion of small unilamellar vesicles of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. The influence of the dilution of the anchoring thiol molecule in the SAM on the vesicle fusion process and on the properties of the resulting tBLMs is studied. It is observed by quartz crystal microbalance that vesicle fusion is a one-step process for a pure TEG-DP SAM as well as for mixed SAMs containing a high concentration of the anchoring thiol. However, upon dilution of the anchoring thiol to moderate concentrations, this process is decelerated and possibly follows a pathway different from that observed on a pure TEG-DP SAM. Electrochemical impedance spectroscopy is used to qualitatively correlate the composition of the SAM to the electrical properties of the tBLM. In this paper we also delineate the necessity of a critical concentration of this anchoring TEG-DP thiol as a requisite for inducing the fusion of vesicles to form a tBLM.

A synthetic redox biofilm made from metalloprotein-prion domain chimera nanowires

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.