@article{Lisdat2020, author = {Lisdat, Fred}, title = {Coupling biology to electrochemistry—future trends and needs}, series = {Journal of Solid State Electrochemistry}, volume = {24}, journal = {Journal of Solid State Electrochemistry}, publisher = {Springer Nature}, issn = {1433-0768}, doi = {10.1007/s10008-020-04714-y}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13639}, pages = {2125 -- 2127}, year = {2020}, abstract = {The coupling of biological entities with electrodes has already quite some history and has reached a status which is not only based on phenomenological descriptions. Nowadays, we are able to effectively couple redox centres within protein molecules to electrochemical transducers. This allows the transduction of a biochemical reaction into an electrode signal with applications mainly in sensing and bioenergetics [1,2,3,4,5,6,7,8]. However, in most cases, this coupling is not direct, and shuttle molecules or side products of the reaction are used. But also for the direct coupling, significant progress has been made, and several enzymes and redox proteins can be addressed directly by electrodes [8,9,10,11,12,13]. The understanding of the functioning of developed systems is, however, in its infancy. Charge and electrostatic interactions have been mostly studied, and for small dipole molecules such as cytochrome c, the situation can be well described [14]. There is a lack of understanding for more complex enzyme molecules which brings a lot of trial and error into research.}, language = {en} } @article{ZhaoRiedelPatarroyoetal.2022, author = {Zhao, Shuang and Riedel, Marc and Patarroyo, Javier and Bast{\´u}s, Neus G. and Puntes, Victor and Zhao, Yue 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{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, A. and Pieper, J. and Zouni, Athina and Wendler, P.}, 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}, doi = {10.1016/j.crstbi.2020.08.003}, 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{SchubartGoebelLisdat2013, author = {Schubart, Ivo and G{\"o}bel, Gero and Lisdat, Fred}, title = {Direkte Kontaktierung des Enzyms (PQQ)-GDH und Elektroden mit Hilfe von polymermodifizierten Nanor{\"o}hren f{\"u}r die Anwendung in Biobrennstoffzellen}, series = {Wissenschaftliche Beitr{\"a}ge 2013}, volume = {17}, journal = {Wissenschaftliche Beitr{\"a}ge 2013}, issn = {0949-8214}, doi = {10.15771/0949-8214_2013_1_3}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-3127}, pages = {17 -- 22}, year = {2013}, abstract = {In dieser Studie pr{\"a}sentieren wir eine Enzymelektrode, bei der ein direkter Elektronentransfer (DET) zwischen der Pyrrolochinolinchinon-abh{\"a}ngigen Glukosedehydrogenase (PQQ)-GDH und einer Elektrode realisiert werden konnte. Hierf{\"u}r wird eine Goldelektrode mit mehrwandigen Kohlenstoffnanor{\"o}hren [engl. multi-walled carbon nanotubes (MWCNT)] modifiziert, anschließend mit einem Copolymer aus Anilinderivaten {\"u}berzogen und dann die (PQQ)-GDH (Acinetobacter calcoaceticus) kovalent immobilisiert. Die gepulste Polymersynthese wird hinsichtlich der Effektivit{\"a}t der bioelektrokatalytischen Umsetzung von Glukose optimiert. Die Glukoseoxidation startet bei einem Potential von -0,1 V vs. Ag/AgCl (1 M KCl) und Stromdichten von bis zu 500 μA/cm² (+0,1 V) k{\"o}nnen erreicht werden. Der Messbereich f{\"u}r Glukose liegt bei 0,1-5 mM (+0,1 V vs. Ag/AgCl). Der dynamische Bereich ist bei h{\"o}herem Potential auf bis zu 100 mM (+0,4 V vs Ag/AgCl) erweitert. Die Elektrode wird als Anode in einer Biobrennstoffzelle (BBZ) mit einer Bilirubinoxidase-modifizierten MWCNT/Gold-Kathode eingesetzt. Beide Elektroden basieren auf einem DET. Das Zellpotential der BBZ betr{\"a}gt 680 ±20 mV und sie erreicht eine maximale Leistungsdichte von 65 μW/cm² (bei einer Zellspannung von 350 mV).}, language = {de} } @misc{RiedelKartchemnikSchoeningetal.2015, author = {Riedel, Marc and Kartchemnik, Julia and Sch{\"o}ning, Michael J. and Lisdat, Fred}, title = {Impedimetrischer DNA Nachweis - Schritte in Richtung sensorischer Anwendung}, series = {Wissenschaftliche Beitr{\"a}ge 2015}, volume = {19}, journal = {Wissenschaftliche Beitr{\"a}ge 2015}, issn = {0949-8214}, doi = {10.15771/0949-8214_2015_1_3}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-3538}, pages = {21 -- 28}, year = {2015}, abstract = {Diese Studie beschreibt einen labelfreien impedimetrischen Sensor auf der Grundlage von kurzen einzelstr{\"a}ngigen DNA-Erkennungselementen f{\"u}r den Nachweis von Hybridisierungsereignissen. Der Fokus der Arbeit liegt auf der Aufkl{\"a}rung des Einflusses der Ziel-DNA-L{\"a}nge und der Erkennungssequenzposition auf die sensorische Leistungsf{\"a}higkeit. Die impedimetrischen Messungen werden in Anwesenheit des Redoxsystems Kaliumhexacyanoferrat (II/III) durchgef{\"u}hrt und zeigen einen Anstieg des Durchtrittswiderstandes nach der Hybridisierung mit komplement{\"a}rer Ziel-DNA mit einer Nachweisgrenze im unteren nanomolaren Bereich. Nach der Hybridisierung kann die Regeneration des Sensors mit deionisiertem Wasser durch die Einstellung effektiver Konvektionsbedingungen erreicht werden und erm{\"o}glicht somit eine Wiederverwendbarkeit des Sensors. Untersuchungen zu l{\"a}ngeren Ziel-DNA-Str{\"a}ngen mit einem zur L{\"o}sung exponierten {\"U}berhang demonstrieren die Anwendbarkeit des impedimetrischen Nachweises f{\"u}r l{\"a}ngere Sequenzen. Allerdings resultiert eine zunehmende {\"U}berhangl{\"a}nge in einer verringerten Durchtrittswiderstands{\"a}nderung. Um die Impedanz{\"a}nderung f{\"u}r l{\"a}ngere Ziel-DNA zu erh{\"o}hen, wird die Erkennungssequenzposition ver{\"a}ndert, sodass ein kleiner {\"U}berhang zur Elektrode ausgerichtet ist. Die Ergebnisse legen nahe, dass DNA in direkter N{\"a}he zur Elektrode einen gr{\"o}ßeren Einfluss auf das impedimetrische Signal besitzt als weiter entfernte DNA.}, language = {de} } @misc{SarauliXuDietzeletal.2014, author = {Sarauli, David and Xu, Chenggang and Dietzel, Birgit and Schulz, Burkhard and Lisdat, Fred}, title = {Effekt unterschiedlich substituierter sulfonierter Polyaniline auf den Elektronentransfer mit pyrrolochinolinchinonabh{\"a}ngiger Glukosehydrogenase}, series = {Wissenschaftliche Beitr{\"a}ge 2014}, volume = {18}, journal = {Wissenschaftliche Beitr{\"a}ge 2014}, issn = {0949-8214}, doi = {10.15771/0949-8214_2014_1_1}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-3285}, pages = {7 -- 15}, year = {2014}, abstract = {Sulfonierte Polyaniline erwiesen sich bereits als geeignete Polymere f{\"u}r den Aufbau von Biosensoren. Aus diesem Grund setzten wir unterschiedlich substituierte Polymerformen f{\"u}r die Untersuchungen der direkten Elektronen{\"u}bertragung zum Redoxenzym PQQ-GDH (Pyrrolochinolinchinon-abh{\"a}ngige Glukosedehydrogenase) ein. Daf{\"u}r wurden zuerst neue Copolymere synthetisiert. Als Basis f{\"u}r die Synthesen wurden 2-Methoxyanilin-5-Sulfons{\"a}ure (MAS), 3-Aminobenzensulfons{\"a}ure (ABS), 3-Aminobenzoes{\"a}ure (AB) und Anilin (AN) ausgew{\"a}hlt und deren Verh{\"a}ltnisse variiert. Alle Copolymere wurden hinsichtlich der direkten Reaktion mit PQQ-GDH untersucht. Diese Wechselwirkung wurde zun{\"a}chst in L{\"o}sung, anschließend auch auf Elektroden beobachtet. Die Ergebnisse zeigen, dass nur die aus MAS- und AN-Einheiten bestehenden Copolymere in der Lage sind, mit dem Enzym in L{\"o}sung direkt zu interagieren, was wahrscheinlich dem Emeraldin Salz (ES) Redoxzustand des Polymers zuzuschreiben ist. Immobilisiert man die Polymere und das Enzym auf Kohlenstoffnanor{\"o}hrenbasierten Elektroden, generiert man direkte Bioelektrokatalyse auch im Falle der aus ABS/AB- und MAS/AB-Einheiten bestehenden Copolymere, die sich nach der Synthese im Pernigranilin Base (PB) Redoxzustand befinden. Im Gegensatz zur Situation in L{\"o}sung kann auf Elektroden das Potential zus{\"a}tzlich genutzt werden, um Elektronen vom Enzym auf das Polymer zu {\"u}bertragen. Solche Polymerbasierten Enzymelektroden besitzen Anwendungspotential in der Sensorik, aber auch in Biobrennstoffzellen.}, language = {de} } @misc{VogtLisdat2004, author = {Vogt, Christian and Lisdat, Fred}, title = {BioHyTec: Biohybride Technologien in der Hauptstadtregion - Kompetenzbildung und Aufbau einer regionalen Wertsch{\"o}pfungskette}, series = {Wissenschaftliche Beitr{\"a}ge 2004}, volume = {9}, journal = {Wissenschaftliche Beitr{\"a}ge 2004}, issn = {0949-8214}, doi = {10.15771/0949-8214_2004_1_15}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-4094}, pages = {97 -- 102}, year = {2004}, abstract = {Das Bundesministerium f{\"u}r Bildung und Forschung (BMBF) startete 1999 mit dem InnoRegio-Wettbewerb eine neuartige F{\"o}rderinitiative unter der Leitidee „Innovative Impulse in den Neuen L{\"a}ndern". In zahlreichen Regionen wurden Aktivit{\"a}ten in Gang gesetzt, um neue Formen der Zusammenarbeit von Menschen aus den unterschiedlichsten Bereichen zu entwickeln und damit die Wertsch{\"o}pfung und Wettbewerbsf{\"a}higkeit in den ostdeutschen Regionen zu erh{\"o}hen. An dieser Ausschreibung nahmen in der Anfangsphase 444 Bewerberregionen teil. Nach der ersten Jury-Sitzung im Oktober 1999 wurden 50 InnoRegios ausgew{\"a}hlt, in einer Entwicklungsphase ihre Kernkompetenzen herauszufiltern und tragf{\"a}hige Innovationskonzepte zu erarbeiten. Mit der zweiten Jury-Sitzung im Herbst 2000 fiel der Startschuss zur Umsetzungsphase. Zur Zeit werden vom BMBF 23 InnoRegios in den Neuen L{\"a}ndern gef{\"o}rdert.}, language = {de} } @article{MorlockSubramanianZounietal.2022, author = {Morlock, Sascha and Subramanian, Senthil Kumar and Zouni, Athina and Lisdat, Fred}, title = {Bio-inorganic hybrid structures for direct electron transfer to photosystem I in photobioelectrodes}, series = {Biosensors and Bioelectronics}, volume = {204}, journal = {Biosensors and Bioelectronics}, publisher = {Elsevier}, issn = {1873-4235}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16770}, year = {2022}, abstract = {Synthetic materials can be combined with biological components in many ways. One example that provides scientists with multiple challenges is a photobioelectrode that converts sunlight into electrons in a biohybrid approach. In the present study several key parameters are evaluated concerning their influence on the direct electron transfer from a 3D indium tin oxide (ITO) electrode material to photosystem I (PSI) as a light-harvesting biomolecule. In contrast to previous investigations, no mediating molecule is added to shuttle the electrons to the luminal side of PSI. Thus, this setup is less complex than foregoing ones. The solution composition drastically influences the interaction of PSI with the ITO surface. Here, the application of higher buffer concentrations and the addition of salts are advantageous, whereas the nature of the buffer ions plays a minor role. The artificial electrode material's thickness is adjustable since a spin-coating procedure is used for preparation. With a 30 μm thick structure and immobilized PSI cathodic photocurrents up to 10.1 μA cm-2 are obtained at 100 mW cm-2 illumination intensity and an applied potential of -0.1V vs. Ag/AgCl. Over a period of three days the photobioelectrodes are illuminated for a total of 90 min and stored between the measurements at ambient temperature. The stability of the setup is noteworthy as still about 90\% of the photocurrent is retained. The photocathode described here offers many positive features, including a high onset potential for the photocurrent starting sligthly above the redox potentail of P700, and applicability in a wide pH range from pH 5 to 8.}, language = {en} } @article{KhalidGoebelHuehnetal.2011, author = {Khalid, Waqas and G{\"o}bel, Gero and H{\"u}hn, Dominik and Montenegro, Jose-Maria and Rivera-Gil, Pilar and Lisdat, Fred and Parak, Wolfgang J.}, title = {Light triggered detection of aminophenyl phosphate with a quantum dot based enzyme electrode}, series = {Journal of Nanobiotechnology}, volume = {9}, journal = {Journal of Nanobiotechnology}, number = {46}, issn = {1477-3155}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5808}, pages = {10}, year = {2011}, abstract = {An electrochemical sensor for p-aminophenyl phosphate (p APP) is reported. It is based on the electrochemical conversion of 4-aminophenol (4AP) at a quantum dot (QD) modified electrode under illumination. Without illumination no electron transfer and thus no oxidation of 4AP can occur. p APP as substrate is converted by the enzyme alkaline phosphatase (ALP) to generate 4AP as a product. The QDs are coupled via 1,4-benzenedithiol (BDT) linkage to the surface of a gold electrode and thus allow potential-controlled photocurrent generation. The photocurrent is modified by the enzyme reaction providing access to the substrate detection. In order to develop a photobioelectrochemical sensor the enzyme is immobilized on top of the photo-switchable layer of the QDs. Immobilization of ALP is required for the potential possibility of spatially resolved measurements. Geometries with immobilized ALP are compared versus having the ALP in solution. Data indicate that functional immobilization with layer-by-layer assembly is possible. Enzymatic activity of ALP and thus the photocurrent can be described by Michaelis- Menten kinetics. p APP is detected as proof of principle investigation within the range of 25 μM - 1 mM.}, language = {en} } @article{FeifelLisdat2011, author = {Feifel, Sven Christian and Lisdat, Fred}, title = {Silica nanoparticles for the layer-by-layer assembly of fully electro-active cytochrome c multilayers}, series = {Journal of Nanobiotechnology}, volume = {9}, journal = {Journal of Nanobiotechnology}, number = {59}, issn = {1477-3155}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5819}, pages = {12}, year = {2011}, abstract = {For bioanalytical systems sensitivity and biomolecule activity are critical issues. The immobilization of proteins into multilayer systems by the layer-by-layer deposition has become one of the favorite methods with this respect. Moreover, the combination of nanoparticles with biomolecules on electrodes is a matter of particular interest since several examples with high activities and direct electron transfer have been found. Our study describes the investigation on silica nanoparticles and the redox protein cytochrome c for the construction of electro-active multilayer architectures, and the electron transfer within such systems. The novelty of this work is the construction of such artificial architectures with a non-conducting building block. Furthermore a detailed study of the size influence of silica nanoparticles is performed with regard to formation and electrochemical behavior of these systems.}, language = {en} } @article{SternPaulyZydeketal.2016, author = {Stern, Daniel and Pauly, Diana and Zydek, Martin and Miller, Lilija and Piesker, Janett and Laue, Michael and Lisdat, Fred and Dorner, Martin B. and Dorner, Brigitte G. and Nitsche, Andreas}, title = {Development of a Genus-Specific Antigen Capture ELISA for Orthopoxviruses - Target Selection and Optimized Screening}, series = {PLoS ONE}, volume = {11}, journal = {PLoS ONE}, number = {3}, issn = {1932-6203}, doi = {10.1371/journal.pone.0150110}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5830}, pages = {22}, year = {2016}, abstract = {Orthopoxvirus species like cowpox, vaccinia and monkeypox virus cause zoonotic infections in humans worldwide. Infections often occur in rural areas lacking proper diagnostic infrastructure as exemplified by monkeypox, which is endemic in Western and Central Africa. While PCR detection requires demanding equipment and is restricted to genome detection, the evidence of virus particles can complement or replace PCR. Therefore, an easily distributable and manageable antigen capture enzyme-linked immunosorbent assay (ELISA) for the detection of orthopoxviruses was developed to facilitate particle detection. By comparing the virus particle binding properties of polyclonal antibodies developed against surface-exposed attachment or fusion proteins, the surface protein A27 was found to be a well-bound, highly immunogenic and exposed target for antibodies aiming at virus particle detection. Subsequently, eight monoclonal anti-A27 antibodies were generated and characterized by peptide epitope mapping and surface plasmon resonance measurements. All antibodies were found to bind with high affinity to two epitopes at the heparin binding site of A27, toward either the N- or C-terminal of the crucial KKEP-segment of A27. Two antibodies recognizing different epitopes were implemented in an antigen capture ELISA. Validation showed robust detection of virus particles from 11 different orthopoxvirus isolates pathogenic to humans, with the exception of MVA, which is apathogenic to humans. Most orthopoxviruses could be detected reliably for viral loads above 1 × 103 PFU/mL. To our knowledge, this is the first solely monoclonal and therefore reproducible antibody-based antigen capture ELISA able to detect all human pathogenic orthopoxviruses including monkeypox virus, except variola virus which was not included. Therefore, the newly developed antibody-based assay represents important progress towards feasible particle detection of this important genus of viruses.}, language = {en} } @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}, doi = {10.1038/srep19858}, 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} } @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{GoebelTalkeAhnertetal.2019, author = {G{\"o}bel, Gero and Talke, Anja and Ahnert, Uwe and Lisdat, Fred}, title = {Electrochemical Activity Determination of Catechol-O-methyl Transferase by Selective Dopamine Detection}, series = {ChemElectroChem}, volume = {6}, journal = {ChemElectroChem}, number = {17}, publisher = {Wiley}, doi = {10.1002/celc.201900856}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13900}, pages = {4533 -- 4540}, year = {2019}, abstract = {Abstract For the treatment of Parkinson's disease, as one of the most frequent diseases of the central nervous system, several key enzymes for dopamine metabolism [e. g. catechol-O-methyl transferase (COMT)] are drug targets. For an efficient and long-lasting treatment, the activity of this enzyme should be monitored. In this study, an electrochemical approach using differential pulse voltammetry (DPV) is introduced for the activity determination. The applied electrode material, fluorine-doped tin oxide (FTO), is characterized by a clear discrimination between substrate and product of COMT, a high stability of the dopamine signal during consecutive measurements, and a linear dependency on the dopamine concentration in the range of the maximum reaction rate of COMT. Despite these advantageous results, dopamine detection in the complete activity assay is influenced by each of the added essential assay components, even though none of the added components reveal a current signal at the FTO electrode itself. After adjusting the potential range and the assay composition, these effects can be circumvented. By following the dopamine concentrations during COMT action, it can be shown that the activity of COMT can be detected by using differential pulse voltammetry (DPV) at an FTO electrode and, by analyzing different COMT amounts, quantification can be demonstrated.}, language = {en} } @article{HeinsohnNiedlAnielskietal.2022, author = {Heinsohn, Natascha Katharina and Niedl, Robert Raimund and Anielski, Alexander and Lisdat, Fred and Beta, Carsten}, title = {Electrophoretic µPAD for Purification and Analysis of DNA Samples}, series = {Biosensors}, volume = {12}, journal = {Biosensors}, number = {2}, publisher = {MDPI}, issn = {2079-6374}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15763}, year = {2022}, abstract = {In this work, the fabrication and characterization of a simple, inexpensive, and effective microfluidic paper analytic device (µPAD) for monitoring DNA samples is reported. The glass microfiber-based chip has been fabricated by a new wax-based transfer-printing technique and an electrode printing process. It is capable of moving DNA effectively in a time-dependent fashion. The nucleic acid sample is not damaged by this process and is accumulated in front of the anode, but not directly on the electrode. Thus, further DNA processing is feasible. The system allows the DNA to be purified by separating it from other components in sample mixtures such as proteins. Furthermore, it is demonstrated that DNA can be moved through several layers of the glass fiber material. This proof of concept will provide the basis for the development of rapid test systems, e.g., for the detection of pathogens in water samples.}, language = {en} } @article{MorlockSubramanianZounietal.2023, author = {Morlock, Sascha and Subramanian, Senthil Kumar and Zouni, Athina and Lisdat, Fred}, title = {Closing the green gap of photosystem I with synthetic fluorophores for enhanced photocurrent generation in photobiocathodes}, series = {Chemical Science}, volume = {14}, journal = {Chemical Science}, publisher = {Royal Society of Chemistry (RSC)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-17022}, pages = {1696 -- 1708}, year = {2023}, abstract = {One restriction for biohybrid photovoltaics is the limited conversion of green light by most natural photoactive components. The present study aims to fill the green gap of photosystem I (PSI) with covalently linked fluorophores, ATTO 590 and ATTO 532. Photobiocathodes are prepared by combining a 20 μm thick 3D indium tin oxide (ITO) structure with these constructs to enhance the photocurrent density compared to setups based on native PSI. To this end, two electron transfer mechanisms, with and without a mediator, are studied to evaluate differences in the behavior of the constructs. Wavelength-dependent measurements confirm the influence of the additional fluorophores on the photocurrent. The performance is significantly increased for all modifications compared to native PSI when cytochrome c is present as a redox-mediator. The photocurrent almost doubles from -32.5 to up to -60.9 μA cm-2. For mediator-less photobiocathodes, interestingly, drastic differences appear between the constructs made with various dyes. While the turnover frequency (TOF) is doubled to 10 e-/PSI/s for PSI-ATTO590 on the 3D ITO compared to the reference specimen, the photocurrents are slightly smaller since the PSI-ATTO590 coverage is low. In contrast, the PSI-ATTO532 construct performs exceptionally well. The TOF increases to 31 e-/PSI/s, and a photocurrent of -47.0 μA cm-2 is obtained. This current is a factor of 6 better than the reference made with native PSI in direct electron transfer mode and sets a new record for mediator-free photobioelectrodes combining 3D electrode structures and light-converting biocomponents.}, language = {en} } @article{MorlockSubramanianZounietal.2021, author = {Morlock, Sascha and Subramanian, Senthil Kumar and Zouni, Athina and Lisdat, Fred}, title = {Scalable Three-Dimensional Photobioelectrodes Made of Reduced Graphene Oxide Combined with Photosystem I}, series = {ACS Applied Materials \& Interfaces}, volume = {13}, journal = {ACS Applied Materials \& Interfaces}, number = {9}, publisher = {American Chemical Society (ACS)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16760}, pages = {11237 -- 11246}, year = {2021}, abstract = {Photobioelectrodes represent one of the examples where artificial materials are combined with biological entities to undertake semi-artificial photosynthesis. Here, an approach is described that uses reduced graphene oxide (rGO) as an electrode material. This classical 2D material is used to construct a three-dimensional structure by a template-based approach combined with a simple spin-coating process during preparation. Inspired by this novel material and photosystem I (PSI), a biophotovoltaic electrode is being designed and investigated. Both direct electron transfer to PSI and mediated electron transfer via cytochrome c from horse heart as redox protein can be confirmed. Electrode preparation and protein immobilization have been optimized. The performance can be upscaled by adjusting the thickness of the 3D electrode using different numbers of spin-coating steps during preparation. Thus, photocurrents up to ∼14 μA/cm2 are measured for 12 spin-coated layers of rGO corresponding to a turnover frequency of 30 e- PSI-1 s-1 and external quantum efficiency (EQE) of 0.07\% at a thickness of about 15 μm. Operational stability has been analyzed for several days. Particularly, the performance at low illumination intensities is very promising (1.39 μA/cm2 at 0.1 mW/cm2 and -0.15 V vs Ag/AgCl; EQE 6.8\%).}, language = {en} } @misc{RiedelSchaeferParaketal.2019, author = {Riedel, Marc and Sch{\"a}fer, Daniel and Parak, Wolfgang J. and Ruff, Adrian and Schuhmann, Wolfgang and Lisdat, Fred}, title = {Quantum Dot-modifizierte TiO2-Strukturen f{\"u}r die Licht-gesteuerte Bioelektrokatalyse}, series = {Wissenschaftliche Beitr{\"a}ge 2019}, volume = {23}, journal = {Wissenschaftliche Beitr{\"a}ge 2019}, issn = {0949-8214}, doi = {10.15771/0949-8214_2019_2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-10773}, pages = {11 -- 17}, year = {2019}, abstract = {Die funktionale Kopplung von photoaktiven Nanostrukturen mit Enzymen stellt eine neue Strategie zum Aufbau lichtgesteuerter biohybrider Systeme dar. Hier sind Untersuchungen zusammengefasst, welche die effiziente Kontaktierung der FAD-abh{\"a}ngigen Glukosedehydrogenase (FAD-GDH) mit Hilfe eines Osmium-Redoxpolymers (P Os ) an PbS-Quantum Dots (PbS QDs) zeigen, welche direkt auf dreidimensionalen TiO 2 -Elektrodenstrukturen synthetisiert wurden. Diese biohybriden Strukturen erlauben die Licht-induzierte Oxidation von Glukose. Dazu wird zun{\"a}chst ein Verfahren vorgestellt, bei welchem durch den Aufbau invers-opaler TiO 2 (IO-TiO 2 ) Strukturen hohe Bindungskapazit{\"a}ten f{\"u}r die Integration von QDs, Redoxpolymer und Enzym erreicht werden. In Folge wird gezeigt wie elektrochemische Signalketten durch Licht gesteuert werden k{\"o}nnen, indem Ladungstr{\"a}ger in den QDs unter Beleuchtung erzeugt werden. Diese Aktivierung erm{\"o}glicht dann die Ausbildung einer Elektrontransferkaskade vom Enzym {\"u}ber das Redoxpolymer zu den QDs und final zur IO-TiO 2 -Elektrode. Die resultierenden anodischen Photostr{\"o}me k{\"o}nnen durch das Potential, die Lichtintensit{\"a}t und die Glukosekonzentration moduliert werden. So k{\"o}nnen in Anwesenheit von Glukose Photostr{\"o}me von bis zu 207 μA/cm2 und erste Oxidationssignale bereits bei einem Potential von -540 mV vs Ag/AgCl, 1 M KCl erhalten werden. Dies entspricht einem Potentialgewinn von {\"u}ber 500 mV im Vergleich zu nicht lichtsensitiven Elektroden. Das vorgestellte biohybride System kombiniert Vorteile einer großen Oberfl{\"a}che (durch IO-TiO 2 -Struktur), die effiziente Ladungstr{\"a}gergenerierung und -trennung an der QD/TiO 2 -Schnittstelle sowie die effiziente Kontaktierung von FAD-GDH mit den QDs mit Hilfe eines Redoxpolymers. Die Ergebnisse verdeutlichen das Potential dieser leistungsf{\"a}higen Photobioanode f{\"u}r die Sensorik und die Erzeugung von Energie aus Licht und Glukose.}, language = {de} } @article{ZhaoCarusoDaehneetal.2019, author = {Zhao, Shuang and Caruso, Frank and D{\"a}hne, Lars and Decher, Gero and De Geest, Bruno G. and Fan, Jinchen and Feliu, Neus and Gogotsi, Yury and Hammond, Paula T. and Hersam, Mark C. and Khademhosseini, Ali and Kotov, Nicholas and Leporatti, Stefano and Li, Yan and Lisdat, Fred and Liz-Marz{\´a}n, Luis M. and Moya, Sergio and Mulvaney, Paul and Rogach, Andrey L. and Roy, Sathi and Shchukin, Dmitry G. and Skirtach, Andre G. and Stevens, Molly M. and Sukhorukov, Gleb B. and Weiss, Paul S. and Yue, Zhao and Zhu, Dingcheng and Parak, Wolfgang J.}, title = {The Future of Layer-by-Layer Assembly: A Tribute to ACS Nano Associate Editor Helmuth M{\"o}hwald}, series = {ACS Nano}, volume = {13}, journal = {ACS Nano}, number = {6}, issn = {1936-086X}, doi = {10.1021/acsnano.9b03326}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-12356}, pages = {6151 -- 6169}, year = {2019}, abstract = {Layer-by-layer (LbL) assembly is a widely used tool for engineering materials and coatings. In this Perspective, dedicated to the memory of ACS Nano associate editor Prof. Dr. Helmuth M{\"o}hwald, we discuss the developments and applications that are to come in LbL assembly, focusing on coatings, bulk materials, membranes, nanocomposites, and delivery vehicles.}, language = {en} } @article{KoelschHejaziStiegeretal.2018, author = {K{\"o}lsch, Adrian and Hejazi, Mahdi and Stieger, Kai Ralf and Feifel, Sven Christian and Kern, Jan F. and M{\"u}h, Frank and Lisdat, Fred and Lokstein, Heiko and Zouni, Athina}, title = {Insights into the binding behavior of native and non-native cytochromes to photosystem I from Thermosynechococcus elongatus}, series = {Journal of Biological Chemistry}, volume = {293}, journal = {Journal of Biological Chemistry}, number = {23}, issn = {1083-351X}, doi = {10.1074/jbc.RA117.000953}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-12780}, pages = {9090 -- 9100}, year = {2018}, abstract = {The binding of photosystem I (PS I) from Thermosynechococcus elongatus to the native cytochrome (cyt) c6 and cyt c from horse heart (cyt cHH) was analyzed by oxygen consumption measurements, isothermal titration calorimetry (ITC), and rigid body docking combined with electrostatic computations of binding energies. Although PS I has a higher affinity for cyt cHH than for cyt c6, the influence of ionic strength and pH on binding is different in the two cases. ITC and theoretical computations revealed the existence of unspecific binding sites for cyt cHH besides one specific binding site close to P700. Binding to PS I was found to be the same for reduced and oxidized cyt cHH. Based on this information, suitable conditions for cocrystallization of cyt cHH with PS I were found, resulting in crystals with a PS I:cyt cHH ratio of 1:1. A crystal structure at 3.4-{\AA} resolution was obtained, but cyt cHH cannot be identified in the electron density map because of unspecific binding sites and/or high flexibility at the specific binding site. Modeling the binding of cyt c6 to PS I revealed a specific binding site where the distance and orientation of cyt c6 relative to P700 are comparable with cyt c2 from purple bacteria relative to P870. This work provides new insights into the binding modes of different cytochromes to PS I, thus facilitating steps toward solving the PS I-cyt c costructure and a more detailed understanding of natural electron transport processes.}, language = {en} }