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Scherbahn V.,Wildau University of Applied Sciences | Putze M.T.,Wildau University of Applied Sciences | Dietzel B.,Institute for Thin Film and Microsensoric Technology | Heinlein T.,TU Darmstadt | And 2 more authors.
Biosensors and Bioelectronics | Year: 2014

Two types of carbon nanotube electrodes (1) buckypaper (BP) and (2) vertically aligned carbon nanotubes (vaCNT) have been used for elaboration of glucose/O2 enzymatic fuel cells exploiting direct electron transfer. For the anode pyrroloquinoline quinone dependent glucose dehydrogenase ((PQQ)GDH) has been immobilized on [poly(3-aminobenzoic acid-co-2-methoxyaniline-5-sulfonic acid), PABMSA]-modified electrodes. For the cathode bilirubin oxidase (BOD) has been immobilized on PQQ-modified electrodes. PABMSA and PQQ act as promoter for enzyme bioelectrocatalysis. The voltammetric characterization of each electrode shows current densities in the range of 0.7-1.3mA/cm2.The BP-based fuel cell exhibits maximal power density of about 107μW/cm2 (at 490mV). The vaCNT-based fuel cell achieves a maximal power density of 122μW/cm2 (at 540mV). Even after three days and several runs of load a power density over 110μW/cm2 is retained with the second system (10mM glucose). Due to a better power exhibition and an enhanced stability of the vaCNT-based fuel cells they have been studied in human serum samples and a maximal power density of 41μW/cm2 (390mV) can be achieved. © 2014 Elsevier B.V.

Tanne J.,Fraunhofer Institute for Cell Therapy and Immunology | Kracher D.,University of Natural Resources and Life Sciences, Vienna | Dietzel B.,Institute for Thin Film and Microsensoric Technology | Schulz B.,Institute for Thin Film and Microsensoric Technology | And 4 more authors.
Biosensors | Year: 2014

Polymer-multiwalled carbon nanotube (MWCNT) nanohybrids, which differ in surface charge have been synthesized to study the bioelectrocatalysis of adsorbed cellobiose dehydrogenase (CDH) from Phanerochaete sordida on gold electrodes. To obtain negatively charged nanohybrids, poly(3-amino-4-methoxybenzoic acid-co-aniline) (P(AMB-A)) was covalently linked to the surface of MWCNTs while modification with p-phenylenediamine (PDA) converted the COOH-groups to positively charged amino groups. Fourier transform infrared spectroscopy (FTIR) measurements verified the p-phenylenediamine (PDA) modification of the polymer-CNT nanohybrids. The positively charged nanohybrid MWCNT-P(AMB-A)-PDA promoted direct electron transfer (DET) of CDH to the electrode and bioelectrocatalysis of lactose was observed. Amperometric measurements gave an electrochemical response with KMapp = 8.89mM and a current density of 410nA/cm2 (15mM lactose). The catalytic response was tested at pH 3.5 and 4.5. Interference by ascorbic acid was not observed. The study proves that DET between the MWCNT-P(AMB-A)-PDA nanohybrids and CDH is efficient and allows the sensorial detection of lactose. © 2014 by the authors.

Tanne J.,Fraunhofer Institute for Cell Therapy and Immunology | Jeoung J.-H.,Humboldt University of Berlin | Peng L.,University of Potsdam | Yarman A.,University of Potsdam | And 8 more authors.
Electroanalysis | Year: 2015

A nanohybrid consisting of poly(3-aminobenzenesulfonic acid-co-aniline) and multiwalled carbon nanotubes [MWCNT-P(ABS-A)]) on a gold electrode was used to immobilize the hexameric tyrosine-coordinated heme protein (HTHP). The enzyme showed direct electron transfer between the heme group of the protein and the nanostructured surface. Desorption of the noncovalently bound heme from the protein could be excluded by control measurements with adsorbed hemin on aminohexanthiol-modified electrodes. The nanostructuring and the optimised charge characteristics resulted in a higher protein coverage as compared with MUA/MU modified electrodes. The adsorbed enzyme shows catalytic activity for the cathodic H2O2 reduction and oxidation of NADH. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tanne J.,Fraunhofer Institute for Biomedical Engineering | Dietzel B.,Institute for Thin Film and Microsensoric Technology | Scheller F.W.,Fraunhofer Institute for Biomedical Engineering | Bier F.,Fraunhofer Institute for Biomedical Engineering
Electroanalysis | Year: 2014

The development of a new surface architecture for the efficient direct electron transfer of positively charged redox proteins is presented. For this reason different kinds of polyaniline terpolymers consisting of aminobenzoic acid (AB), aminobenzenesulfonic acid (ABS) and aniline (A) with different monomer ratios were synthesized. The P(AB-ABS-A) were grafted to the surface of multiwalled carbon nanotubes (MWCNTs). FTIR measurements prove the covalent binding to the carboxylic groups of the MWCNTs while conductivity tests show an increase in the conductivity of the nanohybrid in comparison to the polymers. The [MWCNT-P(AB-ABS-A)] nanohybrids were used for the immobilization of redox active cytochrome c (cyt.c). The positively charged protein can electrostatically interact with the negatively charged nanohybrid. Cyclic voltammetry (CV) shows an increase in the protein loading on [MWCNT-P(AB-ABS-A)] coupled to cysteamine modified gold electrodes in comparison to non-grafted MWCNTs. A further increase in the sulfonation degree of P(AB-ABS-A) leads to an enhanced current output of the modified electrodes. The redox activity of the polymer decreases after the immobilization of the cyt.c on the nanohybrid. For the first time polymers covalently grafted to the surface of MWCNTs are used in a biosensor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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