@misc{WettsteinKanoSchaeferetal.2017, author = {Wettstein, Christoph and Kano, Kenji and Sch{\"a}fer, Daniel and Wollenberger, Ulla and Lisdat, Fred}, title = {Die Flavin-abh{\"a}ngige Fruktosedehydrogenase und Cytochrom c: Elektronentransfer und Sensorstrategien}, series = {Wissenschaftliche Beitr{\"a}ge 2017}, volume = {21}, journal = {Wissenschaftliche Beitr{\"a}ge 2017}, issn = {0949-8214}, doi = {10.15771/0949-8214_2017_2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-9379}, pages = {13 -- 21}, year = {2017}, abstract = {Die hier durchgef{\"u}hrten Untersuchungen erm{\"o}glichen ein besseres Verst{\"a}ndnis der Elektronentransferprozesse zwischen der Flavin-abh{\"a}ngigen Fruktosedehydrogenase (FDH) und dem Redoxprotein Cytochrom c (Cyt c). Dies liefert im Hinblick auf sensorische Anwendungen wichtige Erkenntnisse f{\"u}r vorteilhafte Sensorarchitekturen und deren Messbedingungen. Es wurden zwei unterschiedliche pH-Optima f{\"u}r die Redoxreaktion der beiden Proteine untereinander entdeckt. Die Reaktion wurde im Weiteren mit Elektroden kombiniert und so eine Fruktose-abh{\"a}ngige Stromantwort detektiert. Dar{\"u}ber hinaus konnten definierte dreidimensionale Sensorarchitekturen der beiden Proteine, mit Hilfe von DNA als zus{\"a}tzlichen biologischen Baustein erzeugt und f{\"u}r die Sensorik genutzt werden.}, language = {de} } @misc{StiegerFeifelLoksteinetal.2018, author = {Stieger, Kai Ralf and Feifel, Sven Christian and Lokstein, Heiko and Hejazi, Mahdi and Zouni, Athina and Lisdat, Fred}, title = {Biohybride Architekturen f{\"u}r eine effiziente Umwandlung von Licht in elektrische Energie durch Integration von Photosystem I in skalierbare mesopor{\"o}se 3D Elektroden}, series = {Wissenschaftliche Beitr{\"a}ge 2018}, volume = {22}, journal = {Wissenschaftliche Beitr{\"a}ge 2018}, issn = {0949-8214}, doi = {10.15771/0949-8214_2018_2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-10220}, pages = {17 -- 24}, year = {2018}, abstract = {Die Kombination von fortschrittlichen Materialien und kontrolliertem Oberfl{\"a}chendesign mit komplexen Proteinen aus der nat{\"u}rlichen Photosynthese ist derzeit eines der Hauptthemen bei der Entwicklung von Biohybridsystemen und Biophotovoltaik. In dieser Studie werden transparente makropor{\"o}se Indium-Zinn-Oxid-(μITO-) Elektroden mit dem trimeren Superkomplex Photosystem I (PSI) aus dem Cyanobakterium Thermosynechococcus elongatus sowie dem kleinen Redoxprotein Cytochrom c (Cyt c) kombiniert, um neuartige und effiziente biohybride Photokathoden herzustellen. Mit diesen bis zu 40 μm hohen 3D-Strukturen k{\"o}nnen beide Proteine in einer ann{\"a}hernden Monolage abgeschieden werden und die elektrische Kommunikation mit der Elektrode kann erzielt werden. Der generierte Photostrom folgt dabei linear der kontrollierbaren Schichtdicke der μITO-Elektrode, wobei Stromdichten von bis zu 150 μA cm -2 erhalten werden. Eine effiziente elektrische Kopplung der Proteine kann durch die hohe interne Quanteneffizienz von 30 \% gezeigt werden.}, language = {de} } @article{GoebelDietzLisdat2009, author = {G{\"o}bel, Gero and Dietz, T. and Lisdat, Fred}, title = {Biosensor based on an oxygen reducing bilirubin oxidase electrode}, series = {Procedia Chemistry}, volume = {1}, journal = {Procedia Chemistry}, number = {1}, issn = {1876-6196}, doi = {10.1016/j.proche.2009.07.068}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-6237}, pages = {273 -- 276}, year = {2009}, abstract = {An oxygen reducing electrode made of bilirubin oxidase and multi-walled carbon nanotubes (BOD-MWCNT-Au electrode) is coupled to enzymes catalysing oxygen-consuming reactions such as glucose oxidase (GOD) to result in a membrane-free bienzyme electrode. The feasibility of such a molecularly assembled system stabilized by covalent linkage has been demonstrated. The electrochemical characterisation of the bienzyme electrode reveals sensitivity to the enzyme substrate. The results indicate that the BOD-electrode provides a suitable platform for sensing analytes for which oxidases of high activity are available.}, language = {en} } @article{TanneKracherDietzeletal.2014, author = {Tanne, Johannes and Kracher, Daniel and Dietzel, Birgit and Schulz, Burkhard and Ludwig, Roland and Lisdat, Fred and Scheller, Frieder W. and Bier, Frank Fabian}, title = {Carboxylated or Aminated Polyaniline—Multiwalled Carbon Nanotubes Nanohybrids for Immobilization of Cellobiose Dehydrogenase on Gold Electrodes}, series = {Biosensors}, volume = {4}, journal = {Biosensors}, number = {4}, issn = {2079-6374}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5826}, pages = {370 -- 386}, year = {2014}, abstract = {Polymer-multiwalled carbon nanotube (MWCNT) nanohybrids, which differ in surface charge have been synthesized to study the bioelectrocatalysis of adsorbed cellobiose dehydrogenase (CDH) from Phanerochaete sordida on gold electrodes. To obtain negatively charged nanohybrids, poly(3-amino-4-methoxybenzoic acid-co-aniline) (P(AMB-A)) was covalently linked to the surface of MWCNTs while modification with p-phenylenediamine (PDA) converted the COOH-groups to positively charged amino groups. Fourier transform infrared spectroscopy (FTIR) measurements verified the p-phenylenediamine (PDA) modification of the polymer-CNT nanohybrids. The positively charged nanohybrid MWCNT-P(AMB-A)-PDA promoted direct electron transfer (DET) of CDH to the electrode and bioelectrocatalysis of lactose was observed. Amperometric measurements gave an electrochemical response with KMapp = 8.89 mM and a current density of 410 nA/cm2 (15 mM lactose). The catalytic response was tested at pH 3.5 and 4.5. Interference by ascorbic acid was not observed. The study proves that DET between the MWCNT-P(AMB-A)-PDA nanohybrids and CDH is efficient and allows the sensorial detection of lactose.}, language = {en} } @inproceedings{RiedelGoebelParaketal.2014, author = {Riedel, Marc and G{\"o}bel, Gero and Parak, Wolfgang J. and Lisdat, Fred}, title = {Light-addressable amperometric electrodes for enzyme sensors based on direct quantum dot-electrode contacts}, publisher = {Society of Photo-Optical Instrumentation Engineers (SPIE)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15266}, pages = {195 -- 200}, year = {2014}, abstract = {Quantum dots allow the generation of charge carriers upon illumination. When these particles are attached to an electrode a photocurrent can be generated. This allows their use as a light-switchable layer on the surface. The QDs can not only exchange electronics with the electrode, but can also interact with donor or acceptor compounds in solution providing access to the construction of signal chains starting from an analytic molecule. The magnitude and the direction of the photocurrent depend on several factors such as electrode polarization, solution pH and composition. These defined dependencies have been evaluated with respect to the combination of QD-electrodes with enzyme reactions for sensorial purpose. CdSe/ZnS-QD-modified electrodes can be used to follow enzymatic reactions in solution based on the oxygen sensitivity. In order to develop a photoelectrochemical biosensor, e.g. glucose oxidase is immobilized on the CdSe/ZnS-electrode. One immobilization strategy applies the layer-by-layer-technique of GOD and a polyelectrolyte. Photocurrent measurements of such a sensor show a clear concentration dependent behavior. The principle of combing QD oxidase. The sensitivity of quantum dot electrodes can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be demonstrated that direct electron transfer from excited quantum dots can be achieved with the redox protein cytochrome c. This allows the detection of the protein, but also interaction partners such as a enzymes or superoxide.}, language = {en} } @article{BayBuschLisdatetal.2017, author = {Bay, Daniyah H. and Busch, Annika and Lisdat, Fred and Iida, Keisuke and Ikebukuro, Kazunori and Nagasawa, Kazuo and Karube, Isao and Yoshida, Wataru}, title = {Identification of G-quadruplex structures that possess transcriptional regulating functions in the Dele and Cdc6 CpG islands}, series = {BMC Molecular Biology}, volume = {18}, journal = {BMC Molecular Biology}, number = {17}, issn = {1471-2199}, doi = {10.1186/s12867-017-0094-z}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-9811}, year = {2017}, abstract = {G-quadruplex is a DNA secondary structure that has been shown to play an important role in biological systems. In a previous study, we identified 1998 G-quadruplex-forming sequences using a mouse CpG islands DNA microarray with a fluorescent-labeled G-quadruplex ligand. Among these putative G-quadruplex-forming sequences, G-quadruplex formation was verified for 10 randomly selected sequences by CD spectroscopy and DMS footprinting analysis. In this study, the biological function of the 10 G-quadruplex-forming sequences in the transcriptional regulation has been analyzed using a reporter assay.}, language = {en} }