@article{FrascavonGrabergFengetal.2010, author = {Frasca, Stefano and von Graberg, Till and Feng, Jiu-Ju and Thomas, Arne and Smarsly, Bernd M. and Weidinger, Inez M. and Scheller, Frieder W. and Hildebrandt, Peter and Wollenberger, Ursula}, title = {Mesoporous indium tin oxide as a novel platform for bioelectronics}, issn = {1867-3880}, doi = {10.1002/cctc.201000047}, year = {2010}, abstract = {Stable immobilization and reversible electrochemistry of cytochrome c in a tranparent indium tin oxide film with a well-defined mesoporosity (mpITO) is demonstrated. the transparency and good conductivity, in combination with the large surface area of mpITO, allow the incorporation of a high amount of elelctroactive biomolecules and their electrochemical and spectroscopic investigation. UV/Vis and resonance Raman spectroscopy, in combination with direct protein voltammetry are employed for the characterization of cytochrome c immobilized in the mpITO and reveal no perturbant of the structural of the integrity of the redox protein. The potential of this modified material as a biosensor detection of superoxide anions is also demonstrated.}, language = {en} } @article{FrascaRojasSalewskietal.2012, author = {Frasca, Stefano and Rojas, Oscar and Salewski, Johannes and Neumann, Bettina and Stiba, Konstanze and Weidinger, Inez M. and Tiersch, Brigitte and Leimk{\"u}hler, Silke and Koetz, Joachim and Wollenberger, Ursula}, title = {Human sulfite oxidase electrochemistry on gold nanoparticles modified electrode}, series = {Bioelectrochemistry : an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry ; official journal of the Bioelectrochemical Society}, volume = {87}, journal = {Bioelectrochemistry : an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry ; official journal of the Bioelectrochemical Society}, publisher = {Elsevier}, address = {Lausanne}, issn = {1567-5394}, doi = {10.1016/j.bioelechem.2011.11.012}, pages = {33 -- 41}, year = {2012}, abstract = {The present study reports a facile approach for sulfite biosensing, based on enhanced direct electron transfer of a human sulfite oxidase (hSO) immobilized on a gold nanoparticles modified electrode. The spherical core shell AuNPs were prepared via a new method by reduction of HAuCl4 with branched poly(ethyleneimine) in an ionic liquids resulting particles with a diameter less than 10 nm. These nanoparticles were covalently attached to a mercaptoundecanoic acid modified Au-electrode where then hSO was adsorbed and an enhanced interfacial electron transfer and electrocatalysis was achieved. UV/Vis and resonance Raman spectroscopy, in combination with direct protein voltammetry, are employed for the characterization of the system and reveal no perturbation of the structural integrity of the redox protein. The proposed biosensor exhibited a quick steady-state current response, within 2 s, a linear detection range between 0.5 and 5.4 mu M with a high sensitivity (1.85 nA mu M-1). The investigated system provides remarkable advantages in the possibility to work at low applied potential and at very high ionic strength. Therefore these properties could make the proposed system useful in the development of bioelectronic devices and its application in real samples.}, language = {en} } @article{BergnerFrascaSciutoetal.2012, author = {Bergner, Andre and Frasca, M. and Sciuto, G. and Buscarino, A. and Ngamga, Eulalie Joelle and Fortuna, L. and Kurths, J{\"u}rgen}, title = {Remote synchronization in star networks}, series = {Physical review : E, Statistical, nonlinear and soft matter physics}, volume = {85}, journal = {Physical review : E, Statistical, nonlinear and soft matter physics}, number = {2}, publisher = {American Physical Society}, address = {College Park}, issn = {1539-3755}, doi = {10.1103/PhysRevE.85.026208}, pages = {7}, year = {2012}, abstract = {We study phase synchronization in a network motif with a starlike structure in which the central node's (the hub's) frequency is strongly detuned against the other peripheral nodes. We find numerically and experimentally a regime of remote synchronization (RS), where the peripheral nodes form a phase synchronized cluster, while the hub remains free with its own dynamics and serves just as a transmitter for the other nodes. We explain the mechanism for this RS by the existence of a free amplitude and also show that systems with a fixed or constant amplitude, such as the classic Kuramoto phase oscillator, are not able to generate this phenomenon. Further, we derive an analytic expression which supports our explanation of the mechanism.}, language = {en} } @article{FrascaRichtervonGrabergetal.2011, author = {Frasca, Stefano and Richter, Claudia and von Graberg, Till and Smarsly, Bernd M. and Wollenberger, Ursula}, title = {Electrochemical switchable protein-based optical device}, series = {Engineering in life sciences : Industry, Environment, Plant, Food}, volume = {11}, journal = {Engineering in life sciences : Industry, Environment, Plant, Food}, number = {6}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1618-0240}, doi = {10.1002/elsc.201100079}, pages = {554 -- 558}, year = {2011}, abstract = {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.}, language = {en} }