TY  - JOUR
A1  - Öner, Ibrahim Halil
A1  - Querebillo, Christine Joy
A1  - David, Christin
A1  - Gernert, Ulrich
A1  - Walter, Carsten
A1  - Driess, Matthias
A1  - Leimkühler, Silke
A1  - Ly, Khoa Hoang
A1  - Weidinger, Inez M.
T1  - High electromagnetic field enhancement of TiO2 nanotube electrodes
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - We present the fabrication of TiO2 nanotube electrodes with high biocompatibility and extraordinary spectroscopic properties. Intense surface-enhanced resonance Raman signals of the heme unit of the redox enzyme Cytochromeb(5) were observed upon covalent immobilization of the protein matrix on the TiO2 surface, revealing overall preserved structural integrity and redox behavior. The enhancement factor could be rationally controlled by varying the electrode annealing temperature, reaching a record maximum value of over 70 at 475 degrees C. For the first time, such high values are reported for non-directly surface-interacting probes, for which the involvement of charge-transfer processes in signal amplification can be excluded. The origin of the surface enhancement is exclusively attributed to enhanced localized electric fields resulting from the specific optical properties of the nanotubular geometry of the electrode.
KW  - electromagnetic field enhancement
KW  - photonic crystals
KW  - spectro-electrochemistry
KW  - surface-enhanced Raman spectroscopy
KW  - TiO2 nanotubes
Y1  - 2018
U6  - https://doi.org/10.1002/anie.201802597
SN  - 1433-7851
SN  - 1521-3773
VL  - 57
IS  - 24
SP  - 7225
EP  - 7229
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Han, Xiao Xia
A1  - Li, Junbo
A1  - Öner, Ibrahim Halil
A1  - Zhao, Bing
A1  - Leimkühler, Silke
A1  - Hildebrandt, Peter
A1  - Weidinger, Inez M.
T1  - Nickel electrodes as a cheap and versatile platform for studying structure and function of immobilized redox proteins
JF  - Analytica chimica acta : an international journal devoted to all branches of analytical chemistry
N2  - Practical use of many bioelectronic and bioanalytical devices is limited by the need of expensive materials and time consuming fabrication. Here we demonstrate the use of nickel electrodes as a simple and cheap solid support material for bioelectronic applications. The naturally nanostructured electrodes showed a surprisingly high electromagnetic surface enhancement upon light illumination such that immobilization and electron transfer reactions of the model redox proteins cytochrome b(5) (Cyt b(5)) and cytochrome c (Cyt c) could be followed via surface enhanced resonance Raman spectroscopy. It could be shown that the nickel surface, when used as received, promotes a very efficient binding of the proteins upon preservation of their native structure. The immobilized redox proteins could efficiently exchange electrons with the electrode and could even act as an electron relay between the electrode and solubilized myoglobin. Our results open up new possibility for nickel electrodes as an exceptional good support for bioelectronic devices and biosensors on the one hand and for surface enhanced spectroscopic investigations on the other hand. (C) 2016 Elsevier B.V. All rights reserved.
KW  - Ni electrodes
KW  - Redox proteins
KW  - Surface enhanced Raman spectroscopy
KW  - Electron relay
KW  - Biocompatibility
KW  - Electron transfer
Y1  - 2016
U6  - https://doi.org/10.1016/j.aca.2016.08.053
SN  - 0003-2670
SN  - 1873-4324
VL  - 941
SP  - 35
EP  - 40
PB  - Elsevier
CY  - Amsterdam
ER  -