TY  - JOUR
A1  - Bosserdt, Maria
A1  - Gajovic-Eichelman, Nenad
A1  - Scheller, Frieder W.
T1  - Modulation of direct electron transfer of cytochrome c by use of a molecularly imprinted thin film
JF  - Analytical & bioanalytical chemistry
N2  - We describe the preparation of a molecularly imprinted polymer film (MIP) on top of a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold, where the template cytochrome c (cyt c) participates in direct electron transfer (DET) with the underlying electrode. To enable DET, a non-conductive polymer film is electrodeposited from an aqueous solution of scopoletin and cyt c on to the surface of a gold electrode previously modified with MUA. The electroactive surface concentration of cyt c was 0.5 pmol cm(-2). In the absence of the MUA layer, no cyt c DET was observed and the pseudo-peroxidatic activity of the scopoletin-entrapped protein, assessed via oxidation of Ampliflu red in the presence of hydrogen peroxide, was only 30 % of that for the MIP on MUA. This result indicates that electrostatic adsorption of cyt c by the MUA-SAM substantially increases the surface concentration of cyt c during the electrodeposition step, and is a prerequisite for the productive orientation required for DET. After template removal by treatment with sulfuric acid, rebinding of cyt c to the MUA-MIP-modified electrode occurred with an affinity constant of 100,000 mol(-1) L, a value three times higher than that determined by use of fluorescence titration for the interaction between scopoletin and cyt c in solution. The DET of cyt c in the presence of myoglobin, lysozyme, and bovine serum albumin (BSA) reveals that the MIP layer suppresses the effect of competing proteins.
KW  - Cytochrome c
KW  - Molecularly imprinted polymer film
KW  - Mercaptoundecanoic acid
KW  - Direct electron transfer
KW  - Scopoletin (7-hydroxy-6-methoxycoumarin)
Y1  - 2013
U6  - https://doi.org/10.1007/s00216-013-7009-8
SN  - 1618-2642
VL  - 405
IS  - 20
SP  - 6437
EP  - 6444
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Frasca, Stefano
A1  - Richter, Claudia
A1  - von Graberg, Till
A1  - Smarsly, Bernd M.
A1  - Wollenberger, Ursula
T1  - Electrochemical switchable protein-based optical device
JF  - Engineering in life sciences : Industry, Environment, Plant, Food
N2  - The present work contributes to the development of reusable sensing systems with a visual evaluation of the detection process related to an analyte. An electrochemical switchable protein-based optical device was designed with the core part composed of cytochrome c immobilized in a mesoporous indium tin oxide film. A color-developing redox-sensitive dye was used as switchable component of the system. The cytochrome c-catalyzed oxidation of the dye by hydrogen peroxide is spectroscopically investigated. When the dye is co-immobilized with the protein, its redox state is easily controlled by application of an electrical potential at the supporting material. This enables to electrochemically reset the system to the initial state and repetitive signal generation. The implemented reset function of the color forming reaction will make calibration of small test devices possible. The principle can be extended to other color forming redox reactions and to coupled enzyme systems, such as rapid food testing and indication of critical concentrations of metabolites for health care.
KW  - Cytochrome c
KW  - Electrochemical switch
KW  - Indium tin oxide
KW  - mesoporous materials
KW  - Optical device
Y1  - 2011
U6  - https://doi.org/10.1002/elsc.201100079
SN  - 1618-0240
VL  - 11
IS  - 6
SP  - 554
EP  - 558
PB  - Wiley-Blackwell
CY  - Malden
ER  -