TY  - JOUR
A1  - Frasca, Stefano
A1  - Milan, Anabel Molero
A1  - Guiet, Amandine
A1  - Goebel, Caren
A1  - Perez-Caballero, Fernando
A1  - Stiba, Konstanze
A1  - Leimkühler, Silke
A1  - Fischer, Anna
A1  - Wollenberger, Ursula
T1  - Bioelectrocatalysis at mesoporous antimony doped tin oxide
 electrodes-Electrochemical characterization and direct enzyme
 communication
JF  - ELECTROCHIMICA ACTA
N2  - In this paper we report immobilization and bioelectrocatalysis of human sulfite oxidase (hSO) on nanostructured antimony doped tin oxide (ATO) thin film electrodes. Two types of ATO thin film electrodes were prepared via evaporation induced self-assembly of ATO nanoparticle sols. The use of a porogen results in different porosity and film thickness. Nevertheless both electrode types reveal similar quasi reversible electrochemical behavior for positive and negatively charged small mediators. Facile and durable immobilization of catalytically active enzyme in a direct electron transfer configuration was achieved without further chemical modification of the ATO surfaces. Interestingly, the binding of hSO onto the ATO surface seems to be not only of electrostatic nature, but also originates from a strong interaction between the histidine-tag of the enzyme and the supporting material. This is suggested from stable sulfite dependent bioelectrocatalytic signals at high ionic strength and imidazole desorption experiments. As such, ATO appears as a promising conductive platform for the immobilization of complex enzymes and their application in bioelectrocatalysis. (C) 2013 Elsevier Ltd. All rights reserved.
KW  - Antimony doped tin dioxide
KW  - Sulfite oxidase
KW  - Direct electrochemistry
KW  - Biosensor
KW  - Bioelectrocatalysis
Y1  - 2013
U6  - https://doi.org/10.1016/j.electacta.2013.03.144
SN  - 0013-4686
SN  - 1873-3859
VL  - 110
IS  - 2
SP  - 172
EP  - 180
PB  - PERGAMON-ELSEVIER SCIENCE LTD
CY  - OXFORD
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Nagel, Thomas
A1  - Gajovic-Eichelmann, Nenad
A1  - Fischer, Anna
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Bioelectrocatalysis by Microperoxidase-11 in a Multilayer Architecture of Chitosan Embedded Gold Nanoparticles
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - We report on the redox behaviour of the microperoxidase-11 (MP-11) which has been electrostatically immobilized in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode. MP-11 contains a covalently bound heme c as the redox active group that exchanges electrons with the electrode via the gold nanoparticles. Electroactive surface concentration of MP-11 at high scan rate is between 350+/-50 pmol cm(-2), which reflects a multilayer process. The formal potential (E degrees') of MP-11 in the gold nanoparticles-chitosan film was estimated to be -(267.7+/-2.9) mV at pH 7.0. The heterogeneous electron transfer rate constant (k(s)) starts at 1.21 s(-1) and levels off at 6.45 s(-1) in the scan rate range from 0.1 to 2.0 V s(-1). Oxidation and reduction of MP-11 by hydrogen peroxide and superoxide, respectively have been coupled to the direct electron transfer of MP-11.
KW  - Microperoxidase
KW  - Direct electron transfer
KW  - Nanoparticles
KW  - Hydrogen peroxide
KW  - Superoxide
KW  - Bioelectrocatalysis
Y1  - 2011
U6  - https://doi.org/10.1002/elan.201000535
SN  - 1040-0397
VL  - 23
IS  - 3
SP  - 611
EP  - 618
PB  - Wiley-Blackwell
CY  - Malden
ER  -