TY - JOUR A1 - Stern, Daniel A1 - Pauly, Diana A1 - Zydek, Martin A1 - Miller, Lilija A1 - Piesker, Janett A1 - Laue, Michael A1 - Lisdat, Fred A1 - Dorner, Martin B. A1 - Dorner, Brigitte G. A1 - Nitsche, Andreas T1 - Development of a Genus-Specific Antigen Capture ELISA for Orthopoxviruses – Target Selection and Optimized Screening JF - PLoS ONE N2 - 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. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-5830 SN - 1932-6203 VL - 11 IS - 3 ER - TY - JOUR A1 - Gladisch, Johannes A1 - Sarauli, David A1 - Schäfer, Daniel A1 - Dietzel, Birgit A1 - Schulz, Burkhard A1 - Lisdat, Fred T1 - Towards a novel bioelectrocatalytic platform based on “wiring” of pyrroloquinoline quinone-dependent glucose dehydrogenase with an electrospun conductive polymeric fiber architecture JF - Scientific Reports N2 - 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. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-5846 SN - 2045-2322 VL - 6 ER - TY - GEN A1 - Gladisch, Johannes A1 - Sarauli, David A1 - Schäfer, Daniel A1 - Dietzel, Birgit A1 - Schulz, Burkhard A1 - Lisdat, Fred T1 - Elektrogesponnene Polymerfasern als neuartiges Material für die Bioelektrokatalyse des Enzyms Pyrrolochinolinchinon-abhängige Glucosedehydrogenase T2 - Wissenschaftliche Beiträge 2016 N2 - Es wurde ein dreidimensionales Polymerfasernetzwerk aufgebaut, charakterisiert und anschließend daran das Enzym Pyrrolochinolinchinon-abhängige Glukosedehydrogenase (PQQ)GDH gebunden. Das Polymerfasernetzwerk wurde durch Elektrospinnen einer Mischung des Polymers Polyacrylnitril und verschiedener leitfähiger Polymere der Polyanilin-Familie auf Indium-Zinn-Oxid-Elektroden aufgebracht. Die so hergestellten Fasermatten erwiesen sich bei mikroskopischen Untersuchungen gleichförmig präpariert 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 Ströme nachgewiesen werden. Das Fasernetzwerk fungiert hier nicht nur als Immobilisierungsmatrix, sondern als auch als Teil des Signalwandlers. N2 - A three-dimensional polymeric electrode structure was developed, characterized and subsequently coupled with the enzyme pyrroloquinoline quinone-dependent Glucosedehydrogenase (PQQ)GDH. The polymeric fiber network is produced by means of electrospinning from mixtures of polyacrylonitrile (PAN) and three different sulfonated poylanilines on top of ITO electrodes. The mats are uniform in their overall appearance; average diameters of the fibers produced are in the range of a few hundred nanometers. These polymeric structures can be shown to allow electrochemical conversions as verified with the ferri-/ferrocyanide redox couple. In addition, application in bioelectrocatalysis can be demonstrated. For two of three selected blends of PAN with sulfonated polyanillines, a well-defined bioelectrochemical response is obtained upon covalent fixation of PQQ-GDH to the fiber network and subsequent addition of substrate glucose. The electrospun matrix does not only act here as an immobilization support, but at the same time as a transducing element. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-5293 SN - 0949-8214 VL - 20 SP - 15 EP - 21 ER - TY - JOUR A1 - Göbel, Gero A1 - Talke, Anja A1 - Ahnert, Uwe A1 - Lisdat, Fred T1 - Electrochemical Activity Determination of Catechol-O-methyl Transferase by Selective Dopamine Detection JF - ChemElectroChem N2 - 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. KW - catechol-O-methyl transferase KW - dopamine KW - flow system KW - fluorine-doped tin oxide KW - sensing Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13900 VL - 6 IS - 17 SP - 4533 EP - 4540 PB - Wiley ER - TY - JOUR A1 - Heinsohn, Natascha Katharina A1 - Niedl, Robert Raimund A1 - Anielski, Alexander A1 - Lisdat, Fred A1 - Beta, Carsten T1 - Electrophoretic µPAD for Purification and Analysis of DNA Samples JF - Biosensors N2 - 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. KW - microfluidic paper analytic device (µPAD) KW - patterning glass microfiber KW - fiber-electrophoresis chip KW - DNA KW - imprinted electrodes KW - cross layer chip KW - polymerase chain reaction (PCR) KW - purification Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15763 SN - 2079-6374 VL - 12 IS - 2 PB - MDPI ER - TY - JOUR A1 - Morlock, Sascha A1 - Subramanian, Senthil Kumar A1 - Zouni, Athina A1 - Lisdat, Fred T1 - Closing the green gap of photosystem I with synthetic fluorophores for enhanced photocurrent generation in photobiocathodes JF - Chemical Science N2 - 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. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-17022 VL - 14 SP - 1696 EP - 1708 PB - Royal Society of Chemistry (RSC) ER - TY - JOUR A1 - Morlock, Sascha A1 - Subramanian, Senthil Kumar A1 - Zouni, Athina A1 - Lisdat, Fred T1 - Scalable Three-Dimensional Photobioelectrodes Made of Reduced Graphene Oxide Combined with Photosystem I JF - ACS Applied Materials & Interfaces N2 - 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%). KW - biophotovoltaics KW - reduced graphene oxide (rGO) KW - scalable template process KW - spin-coating KW - 3D electrode structure KW - carbon material Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-16760 VL - 13 IS - 9 SP - 11237 EP - 11246 PB - American Chemical Society (ACS) ER - TY - GEN A1 - Riedel, Marc A1 - Schäfer, Daniel A1 - Parak, Wolfgang J. A1 - Ruff, Adrian A1 - Schuhmann, Wolfgang A1 - Lisdat, Fred T1 - Quantum Dot-modifizierte TiO2-Strukturen für die Licht-gesteuerte Bioelektrokatalyse T2 - Wissenschaftliche Beiträge 2019 N2 - 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-abhängigen 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 zunächst ein Verfahren vorgestellt, bei welchem durch den Aufbau invers-opaler TiO 2 (IO-TiO 2 ) Strukturen hohe Bindungskapazitäten für die Integration von QDs, Redoxpolymer und Enzym erreicht werden. In Folge wird gezeigt wie elektrochemische Signalketten durch Licht gesteuert werden können, indem Ladungsträger in den QDs unter Beleuchtung erzeugt werden. Diese Aktivierung ermöglicht dann die Ausbildung einer Elektrontransferkaskade vom Enzym über das Redoxpolymer zu den QDs und final zur IO-TiO 2 -Elektrode. Die resultierenden anodischen Photoströme können durch das Potential, die Lichtintensität und die Glukosekonzentration moduliert werden. So können in Anwesenheit von Glukose Photoströme 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 über 500 mV im Vergleich zu nicht lichtsensitiven Elektroden. Das vorgestellte biohybride System kombiniert Vorteile einer großen Oberfläche (durch IO-TiO 2 -Struktur), die effiziente Ladungsträgergenerierung 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 leistungsfähigen Photobioanode für die Sensorik und die Erzeugung von Energie aus Licht und Glukose. N2 - The combination of photoactive nanostructures with enzymes represents a new strategy for the construction of light-directed biohybrid systems. The study demonstrates the efficient linkage of FAD-dependent glucose dehydrogenase (FAD-GDH) to PbS quantum dot (QD)-sensitized inverse opal TiO 2 (IO-TiO 2 ) electrodes using an osmium redox polymer (P Os ). How these biohybrid structures can oxidize glucose in a light-directed fashion is highlighted in detail. For this purpose, firstly a method for the construction of IO-TiO 2 electrodes is presented, which gives rise to high binding capacities for the integration of QDs, redox polymer and enzyme. It can be shown how electrochemical signal chains can be controlled with light, resulting in a generation of charge carriers within the QDs. The activation of the electron transfer cascade then allows for an electron transfer from the enzyme via the redox polymer to the QDs and finally to the IO-TiO 2 electrode. The resulting anodic photocurrents can be modulated by potential, light intensity and glucose concentration. In the presence of glucose, photocurrents of up to 207 μA/cm 2 can be generated and first electron withdrawal from the biocatalytic sugar oxidation already proceeds at a potential of -540 mV vs Ag/AgCl (1 M KCl). This corresponds to a potential gain of over 500 mV compared to light-insensitive electrodes. The proposed biohybrid system combines the advantages of a large surface area (IO-TiO 2 ), efficient charge carrier generation (PbS QDs) and separation at the TiO 2 /QDs interface and the efficient linkage of FAD-GDH to the QDs using a redox polymer. This illustrates the potential of this powerful photobioanode for sensing and power supply. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10773 SN - 0949-8214 VL - 23 SP - 11 EP - 17 ER - TY - JOUR A1 - Zhao, Shuang A1 - Caruso, Frank A1 - Dähne, Lars A1 - Decher, Gero A1 - De Geest, Bruno G. A1 - Fan, Jinchen A1 - Feliu, Neus A1 - Gogotsi, Yury A1 - Hammond, Paula T. A1 - Hersam, Mark C. A1 - Khademhosseini, Ali A1 - Kotov, Nicholas A1 - Leporatti, Stefano A1 - Li, Yan A1 - Lisdat, Fred A1 - Liz-Marzán, Luis M. A1 - Moya, Sergio A1 - Mulvaney, Paul A1 - Rogach, Andrey L. A1 - Roy, Sathi A1 - Shchukin, Dmitry G. A1 - Skirtach, Andre G. A1 - Stevens, Molly M. A1 - Sukhorukov, Gleb B. A1 - Weiss, Paul S. A1 - Yue, Zhao A1 - Zhu, Dingcheng A1 - Parak, Wolfgang J. T1 - The Future of Layer-by-Layer Assembly: A Tribute to ACS Nano Associate Editor Helmuth Möhwald JF - ACS Nano N2 - 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 Möhwald, we discuss the developments and applications that are to come in LbL assembly, focusing on coatings, bulk materials, membranes, nanocomposites, and delivery vehicles. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12356 SN - 1936-086X VL - 13 IS - 6 SP - 6151 EP - 6169 ER - TY - JOUR A1 - Kölsch, Adrian A1 - Hejazi, Mahdi A1 - Stieger, Kai Ralf A1 - Feifel, Sven Christian A1 - Kern, Jan F. A1 - Müh, Frank A1 - Lisdat, Fred A1 - Lokstein, Heiko A1 - Zouni, Athina T1 - Insights into the binding behavior of native and non-native cytochromes to photosystem I from Thermosynechococcus elongatus JF - Journal of Biological Chemistry N2 - 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-Å 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. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12780 SN - 1083-351X VL - 293 IS - 23 SP - 9090 EP - 9100 ER -