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  - Couturier, Jean-Philippe
A1  - Sütterlin, Martin
A1  - Laschewsky, André
A1  - Hettrich, Cornelia
A1  - Wischerhoff, Erik
T1  - Responsive Inverse Opal Hydrogels for the Sensing of Macromolecules
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Dual responsive inverse opal hydrogels were designed as autonomous sensor systems for (bio)macromolecules, exploiting the analyte-induced modulation of the opal's structural color. The systems that are based on oligo(ethylene glycol) macromonomers additionally incorporate comonomers with various recognition units. They combine a coil-to-globule collapse transition of the LCST type with sensitivity of the transition temperature toward molecular recognition processes. This enables the specific detection of macromolecular analytes, such as glycopolymers and proteins, by simple optical methods. While the inverse opal structure assists the effective diffusion even of large analytes into the photonic crystal, the stimulus responsiveness gives rise to strong shifts of the optical Bragg peak of more than 100nm upon analyte binding at a given temperature. The systems' design provides a versatile platform for the development of easy-to-use, fast, and low-cost sensors for pathogens.
KW  - hydrogels
KW  - photonic crystals
KW  - polymers
KW  - responsive materials
KW  - sensors
Y1  - 2015
U6  - https://doi.org/10.1002/anie.201500674
SN  - 1433-7851
SN  - 1521-3773
VL  - 54
IS  - 22
SP  - 6641
EP  - 6644
PB  - Wiley-VCH
CY  - Weinheim
ER  -