@misc{SchubertKhalidYueetal.2010, author = {Schubert, Kirsten and Khalid, Waqas and Yue, Zhao and Parak, Wolfgang J. and Lisdat, Fred}, title = {Halbleiternanopartikel-modifizierte Elektrode zum Nachweis von Substraten von NADH-abh{\"a}ngigen Enzymreaktionen}, series = {Wissenschaftliche Beitr{\"a}ge 2009/2010}, volume = {14}, journal = {Wissenschaftliche Beitr{\"a}ge 2009/2010}, issn = {0949-8214}, doi = {10.15771/0949-8214_2010_1_2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus-810}, pages = {13 -- 22}, year = {2010}, abstract = {Es wurde ein Elektrodensystem entwickelt, das aufbauend auf Halbleiternanopartikeln (so genannte Quantenpunkte) die sensitive Detektion des Enzymkofaktors NADH (nicotinamide adenine dinucleotide) erlaubt. Kolloidale halbleitende CdSe/ZnS-Nanokristalle sind durch ein Dithiol {\"u}ber Chemisorption an Gold gebunden. Das Stromsignal kann durch die Beleuchtung der Quantenpunkt modifizierten Oberfl{\"a}che beeinflusst werden. Durch Photoanregung entstehen Elektron-Loch- Paare in den Nanopartikeln, die als anodischer oder kathodischer Photostrom detektiert werden k{\"o}nnen. Die Immobilisierung der Nanokristalle ist durch amperometrische Photostrom- und Quarzmikrowaage-Messungen (quartz crystal microbalance) verifiziert. Diese Studie zeigt, dass CdSe/ZnS-Quantenpunktmodifizierte Elektroden eine konzentrationsabh{\"a}ngige NADH-Detektion im Bereich von 20μM bis 2mM bei relativ niedrigem Potential (um 0V vs Ag/AgCl, 1 M KCl) erm{\"o}glichen. Somit k{\"o}nnen solche Elektroden in Kombination mit NADH-produzierenden Reaktionen f{\"u}r die lichtgesteuerte Analyse der entsprechenden Substrate des Biokatalysators genutzt werden. Es wird gezeigt, dass mit einem solchen Elektrodensystem und Photostrommessungen ein Glukosenachweis m{\"o}glich ist.}, language = {de} } @misc{TanneGoebelLisdat2011, author = {Tanne, Christoph K. and G{\"o}bel, Gero and Lisdat, Fred}, title = {Entwicklung einer Glucosedehydrogenase-basierten Anode und deren Anwendung in einer Glucose/O2-Biobrennstoffzelle}, series = {Wissenschaftliche Beitr{\"a}ge 2011}, volume = {15}, journal = {Wissenschaftliche Beitr{\"a}ge 2011}, issn = {0949-8214}, doi = {10.15771/0949-8214_2011_1_2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus-1039}, pages = {13 -- 21}, year = {2011}, abstract = {Unter Verwendung von mehrwandigen Kohlenstoffnanor{\"o}hren wurde in dieser Studie eine neuartige Anode zum Einsatz in Biobrennstoffzellen entwickelt. Dazu wurde das rekombinante Enzym Pyrrolochinolinchinon(PQQ)- abh{\"a}ngige Glucosedehydrogenase kovalent an eine aus PQQ bestehenden Zwischenschicht gekoppelt, welche zuvor an die Kohlenstoffnanor{\"o}hren adsorbiert war. Die Nanor{\"o}hren wurden aufgrund ihrer Thiolmodifikation chemisorptiv auf einer Goldelektrode gebunden. In glucosehaltiger L{\"o}sung konnte der Start eines katalytischen Stroms bei einem Potential von -80 mV vs. Ag/AgCl (1 MKCl) beobachtet werden. Unter Substrats{\"a}ttigung wurden Stromdichten im Bereich von 170 bis 200 μA/cm2 gemessen. Dieses System basiert auf einem mediatorvermittelten Elektronentransfer. Die entwickelte (PQQ)-GDH-MWCNT-Elektrode wurde mit einer MWCNT-modifizierten Elektrode kombiniert, bei der Bilirubinoxidase (BOD) als Biokatalysator fungiert. Daraus resultierte eine membranfreie Biobrennstoffzelle mit einem leichgewichtspotential von 600 mV und Leistungsdichten im Bereich von 20-25 μW/cm2.}, language = {de} } @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} } @article{KoelschRadonGolubetal.2020, author = {K{\"o}lsch, Adrian and Radon, C. and Golub, M. and Baumert, A. and B{\"u}rger, J{\"o}rg and Mielke, Thorsten and Lisdat, Fred and Feoktystov, Artem and Pieper, J{\"o}rg and Zouni, Athina and Wendler, Petra}, title = {Current limits of structural biology: The transient interaction between cytochrome c6 and photosystem I}, series = {Current Research in Structural Biology}, volume = {2}, journal = {Current Research in Structural Biology}, issn = {2665-928X}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13628}, pages = {171 -- 179}, year = {2020}, abstract = {Trimeric photosystem I from the cyanobacterium Thermosynechococcus elongatus (TePSI) is an intrinsic membrane protein, which converts solar energy into electrical energy by oxidizing the soluble redox mediator cytochrome c6 (Cyt c6) and reducing ferredoxin. Here, we use cryo-electron microscopy and small angle neutron scattering (SANS) to characterize the transient binding of Cyt c6 to TePSI. The structure of TePSI cross-linked to Cyt c6 was solved at a resolution of 2.9 {\AA} and shows additional cofactors as well as side chain density for 84\% of the peptide chain of subunit PsaK, revealing a hydrophobic, membrane intrinsic loop that enables binding of associated proteins. Due to the poor binding specificity, Cyt c6 could not be localized with certainty in our cryo-EM analysis. SANS measurements confirm that Cyt c6 does not bind to TePSI at protein concentrations comparable to those for cross-linking. However, SANS data indicate a complex formation between TePSI and the non-native mitochondrial cytochrome from horse heart (Cyt cHH). Our study pinpoints the difficulty of identifying very small binding partners (less than 5\% of the overall size) in EM structures when binding affinities are poor. We relate our results to well resolved co-structures with known binding affinities and recommend confirmatory methods for complexes with KM values higher than 20 μM.}, language = {en} } @misc{TerschLisdat2012, author = {Tersch, Christoph and Lisdat, Fred}, title = {Labelfreie Detektion von Protein-DNA-Interaktionen durch elektrochemische Impedanzspektroskopie}, series = {Wissenschaftliche Beitr{\"a}ge 2012}, volume = {16}, journal = {Wissenschaftliche Beitr{\"a}ge 2012}, issn = {0949-8214}, doi = {10.15771/0949-8214_2012_1_3}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus-1346}, pages = {23 -- 30}, year = {2012}, abstract = {Es wird ein impedimetrisches Sensorsystem f{\"u}r den Nachweis von Protein-DNA-Wechselwirkungen vorgestellt. Der Sensor nutzt kurze Thiol-markierte DNA (ssDNA), die {\"u}ber Chemisorption auf Goldchipelektroden immobilisiert wird. Aus den Impedanzspektren wurde der Durchtrittswiderstand (Rct) als Kenngr{\"o}ße f{\"u}r die zu untersuchenden Wechselwirkungen gew{\"a}hlt. In Anwesenheit des Redoxsystems Ferro-/Ferrycyanid konnte eine Zunahme des Durchtrittswiderstandes nach der Immobilisierung und anschließender Hybridisierung auf der Sensoroberfl {\"a}che registriert werden. Der Einsatz l{\"a}ngerer F{\"a}nger-DNA (25-mer im Vergleich zu 18-mer) f{\"u}hrte zu einer Abnahme der Konzentration an immobilisierten F{\"a}nger-Str{\"a}ngen, aber auch zu einer Vergr{\"o}ßerung der Durchtrittswiderst{\"a}nde sowohl f{\"u}r ssDNA als auch dsDNA. Bei {\"a}hnlichen Oberfl{\"a}chenkonzentrationen ließ sich eine ann{\"a}hernd gleiche Sensitivit{\"a}t des Hybridisierungsnachweises im Vergleich zu 18-mer F{\"a}nger-Str{\"a}ngen erzielen. Mit Hilfe des Elektrodensystems wurde die Nachweisbarkeit von Protein-DNA-Wechselwirkungen untersucht. Die Restriktion doppelstr{\"a}ngiger DNA durch die Restriktionsendonuklease BamHI konnte mit der Zyklovoltammetrie und markierungsfrei mit der Impedanzspektroskopie verfolgt werden. Des Weiteren wurde die sequenzspezifische Bindung des Transkriptionsfaktors NF-κB p50 anhand einer Abnahme von Rct impedimetrisch registriert.}, language = {de} } @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}, 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} } @article{ZhaoRiedelPatarroyoetal.2022, author = {Zhao, Shuang and Riedel, Marc and Patarroyo, Javier and Bast{\´u}s, Neus G. and Puntes, Victor and Yue, Zhao and Lisdat, Fred and Parak, Wolfgang J.}, title = {Tailoring of the photocatalytic activity of CeO₂ nanoparticles by the presence of plasmonic Ag nanoparticles}, series = {Nanoscale}, volume = {14}, journal = {Nanoscale}, publisher = {Royal Society of Chemistry (RSC)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16361}, pages = {12048 -- 12059}, year = {2022}, abstract = {The present study investigates basic features of a photoelectrochemical system based on CeO2 nanoparticles fixed on gold electrodes. Since photocurrent generation is limited to the absorption range of the CeO2 in the UV range, the combination with metal nanoparticles has been studied. It can be shown that the combination of silver nanoparticles with the CeO2 can shift the excitation range into the visible light wavelength range. Here a close contact between both components has been found to be essential and thus, hybrid CeO2@Ag nanoparticles have been prepared and analyzed. We have collected arguments that electron transfer occurs between both compositional elements of the hybrid nanoparticles.The photocurrent generation can be rationalized on the basis of an energy diagram underlying the necessity of surface plasmon excitation in the metal nanoparticles, which is also supported by wavelength-dependent photocurrent measurements. However, electrochemical reactions seem to occur at the CeO2 surface and consequently, the catalytic properties of this material can be exploited as exemplified with the photoelectrochemical reduction of hydrogen peroxide. It can be further demonstrated that the layer-by layer technique can be exploited to create a multilayer system on top of a gold electrode which allows the adjustment of the sensitivity of the photoelectrochemical system. Thus, with a 5-layer electrode with hybrid CeO2@Ag nanoparticles submicromolar hydrogen peroxide concentrations can be detected.}, language = {en} } @article{RiedelHoefsRuffetal.2021, author = {Riedel, Marc and H{\"o}fs, Soraya and Ruff, Adrian and Schuhmann, Wolfgang and Lisdat, Fred}, title = {A Tandem Solar Biofuel Cell: Harnessing Energy from Light and Biofuels}, series = {Angewandte Chemie International Edition}, volume = {60}, journal = {Angewandte Chemie International Edition}, number = {4}, publisher = {Wiley}, issn = {1521-3773}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13680}, pages = {2078 -- 2083}, year = {2021}, abstract = {We report on a photobioelectrochemical fuel cell consisting of a glucose-oxidase-modified BiFeO3 photobiocathode and a quantum-dot-sensitized inverse opal TiO2 photobioanode linked to FAD glucose dehydrogenase via a redox polymer. Both photobioelectrodes are driven by enzymatic glucose conversion. Whereas the photobioanode can collect electrons from sugar oxidation at rather low potential, the photobiocathode shows reduction currents at rather high potential. The electrodes can be arranged in a sandwich-like manner due to the semi-transparent nature of BiFeO3, which also guarantees a simultaneous excitation of the photobioanode when illuminated via the cathode side. This tandem cell can generate electricity under illumination and in the presence of glucose and provides an exceptionally high OCV of about 1 V. The developed semi-artificial system has significant implications for the integration of biocatalysts in photoactive entities for bioenergetic purposes, and it opens up a new path toward generation of electricity from sunlight and (bio)fuels.}, language = {en} } @misc{GladischSarauliSchaeferetal.2016, author = {Gladisch, Johannes and Sarauli, David and Sch{\"a}fer, Daniel and Dietzel, Birgit and Schulz, Burkhard and Lisdat, Fred}, title = {Elektrogesponnene Polymerfasern als neuartiges Material f{\"u}r die Bioelektrokatalyse des Enzyms Pyrrolochinolinchinon-abh{\"a}ngige Glucosedehydrogenase}, series = {Wissenschaftliche Beitr{\"a}ge 2016}, volume = {20}, journal = {Wissenschaftliche Beitr{\"a}ge 2016}, issn = {0949-8214}, doi = {10.15771/0949-8214_2016_1_2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5293}, pages = {15 -- 21}, year = {2016}, abstract = {Es wurde ein dreidimensionales Polymerfasernetzwerk aufgebaut, charakterisiert und anschließend daran das Enzym Pyrrolochinolinchinon-abh{\"a}ngige Glukosedehydrogenase (PQQ)GDH gebunden. Das Polymerfasernetzwerk wurde durch Elektrospinnen einer Mischung des Polymers Polyacrylnitril und verschiedener leitf{\"a}higer Polymere der Polyanilin-Familie auf Indium-Zinn-Oxid-Elektroden aufgebracht. Die so hergestellten Fasermatten erwiesen sich bei mikroskopischen Untersuchungen gleichf{\"o}rmig pr{\"a}pariert und die Faserdurchmesser bewegten sich im Bereich weniger hundert Nanometer. Das Redoxpaar Kaliumhexacyanoferrat (II/III) zeigte an diesen Polymer-Elektrodenstrukturen eine quasi-reversible Elektrochemie. Bei weitergehenden Untersuchungen an den enzymmodifizierten Fasern ((PQQ)GDH) konnten unter Substratzugabe (Glukose) bioelektrokatalytische Str{\"o}me nachgewiesen werden. Das Fasernetzwerk fungiert hier nicht nur als Immobilisierungsmatrix, sondern als auch als Teil des Signalwandlers.}, language = {de} } @article{GladischSarauliSchaeferetal.2016, author = {Gladisch, Johannes and Sarauli, David and Sch{\"a}fer, Daniel and Dietzel, Birgit and Schulz, Burkhard and Lisdat, Fred}, title = {Towards a novel bioelectrocatalytic platform based on "wiring" of pyrroloquinoline quinone-dependent glucose dehydrogenase with an electrospun conductive polymeric fiber architecture}, series = {Scientific Reports}, volume = {6}, journal = {Scientific Reports}, issn = {2045-2322}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5846}, pages = {10}, year = {2016}, abstract = {Electrospinning is known as a fabrication technique for electrode architectures that serve as immobilization matrices for biomolecules. The current work demonstrates a novel approach to construct a conductive polymeric platform, capable not only of immobilization, but also of electrical connection of the biomolecule with the electrode. It is produced upon electrospinning from mixtures of three different highly conductive sulfonated polyanilines and polyacrylonitrile on ITO electrodes. The resulting fiber mats are with a well-retained conductivity. After coupling the enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) to polymeric structures and addition of the substrate glucose an efficient bioelectrocatalysis is demonstrated. Depending on the choice of the sulfonated polyanilline mediatorless bioelectrocatalysis starts at low potentials; no large overpotential is needed to drive the reaction. Thus, the electrospun conductive immobilization matrix acts here as a transducing element, representing a promising strategy to use 3D polymeric scaffolds as wiring agents for active enzymes. In addition, the mild and well reproducible fabrication process and the active role of the polymer film in withdrawing electrons from the reduced PQQ-GDH lead to a system with high stability. This could provide access to a larger group of enzymes for bioelectrochemical applications including biosensors and biofuel cells.}, language = {en} }