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  - Sivanesan, Arumugam
A1  - Kalaivani, Govindasamy
A1  - Fischer, Anna
A1  - Stiba, Konstanze
A1  - Leimkühler, Silke
A1  - Weidinger, Inez M.
T1  - Complementary surface-enhanced resonance raman Spectroscopic Biodetection of mixed protein solutions by Chitosan- and Silica-Coated Plasmon-Tuned Silver Nanoparticles
JF  - Analytical chemistry
N2  - Silver nanoparticles with identical plasmonic properties but different surface functionalities are synthesized and tested as chemically selective surface-enhanced resonance Raman (SERR) amplifiers in a two-component protein solution. The surface plasmon resonances of the particles are tuned to 413 nm to match the molecular resonance of protein heme cofactors. Biocompatible functionalization of the nanoparticles with a thin film of chitosan yields selective SERR enhancement of the anionic protein cytochrome b(5), whereas functionalization with SiO2 amplifies only the spectra of the cationic protein cytochrome c. As a result, subsequent addition of the two differently functionalized particles yields complementary information on the same mixed protein sample solution. Finally, the applicability of chitosan-coated Ag nanoparticles for protein separation was tested by in situ resonance Raman spectroscopy.
Y1  - 2012
U6  - https://doi.org/10.1021/ac301001a
SN  - 0003-2700
VL  - 84
IS  - 13
SP  - 5759
EP  - 5764
PB  - American Chemical Society
CY  - Washington
ER  -