TY  - JOUR
A1  - Sivanesan, Arumugam
A1  - Ly, Khoa H.
A1  - Adamkiewicz, Witold
A1  - Stiba, Konstanze
A1  - Leimkühler, Silke
A1  - Weidinger, Inez M.
T1  - Tunable electric field enhancement and redox chemistry on TiO2 Island films via covalent attachment to Ag or Au nanostructures
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Ag-TiO2 and Au-TiO2 hybrid electrodes were designed by covalent attachment of TiO2 nanoparticles to Ag or Au electrodes via an organic linker. The optical and electronic properties of these systems were investigated using the cytochrome b(5) (Cyt b(5)) domain of sulfite oxidase, exclusively attached to the TiO2 surface, as a Raman marker and model redox enzyme. Very strong SERR signals of Cyt b(5) were obtained for Ag-supported systems due to plasmonic field enhancement of Ag. Time-resolved surface-enhanced resonance Raman spectroscopic measurements yielded a remarkably fast electron transfer kinetic (k = 60 s(-1)) of Cyt b(5) to Ag. A much lower Raman intensity was observed for Au-supported systems with undefined and slow redox behavior. We explain this phenomenon on the basis of the different potential of zero charge of the two metals that largely influence the electronic properties of the TiO2 island film.
Y1  - 2013
U6  - https://doi.org/10.1021/jp4032578
SN  - 1932-7447
VL  - 117
IS  - 22
SP  - 11866
EP  - 11872
PB  - American Chemical Society
CY  - Washington
ER  - 
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  -