@misc{AbdelghaniMenaaObareetal.2013, author = {Abdelghani, Adnane and Menaa, Bouzid and Obare, Sherine O. and Sch{\"o}ning, Michael Josef}, title = {Special issue on nanoscale science and technology / guest eds.: Adnane Abdelghani, Bouzid Menaa, Sherine O. Obare, Michael J. Sch{\"o}ning}, series = {International journal of nanotechnology}, volume = {Vol. 10}, journal = {International journal of nanotechnology}, number = {No. 5-7}, issn = {1741-8151 (E-Journal), 1475-7435 (Print)}, pages = {373 -- 619}, year = {2013}, language = {en} } @article{AboulnagaZouSelmeretal.2018, author = {Aboulnaga, E. A. and Zou, H. and Selmer, Thorsten and Xian, M.}, title = {Development of a plasmid-based, tunable, tolC-derived expression system for application in Cupriavidus necator H16}, series = {Journal of Biotechnology}, volume = {274}, journal = {Journal of Biotechnology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2018.03.007}, pages = {15 -- 27}, year = {2018}, abstract = {Cupriavidus necator H16 gains increasing attention in microbial research and biotechnological application due to its diverse metabolic features. Here we present a tightly controlled gene expression system for C. necator including the pBBR1-vector that contains hybrid promoters originating from C. necator native tolC-promoter in combination with a synthetic tetO-operator. The expression of the reporter gene from these plasmids relies on the addition of the exogenous inducer doxycycline (dc). The novel expression system offers a combination of advantageous features as; (i) high and dose-dependent recombinant protein production, (ii) tight control with a high dynamic range (On/Off ratio), which makes it applicable for harmful pathways or for toxic protein production, (iii) comparable cheap inducer (doxycycline, dc), (iv) effective at low inducer concentration, that makes it useful for large scale application, (v) rapid, diffusion controlled induction, and (vi) the inducer does not interfere within the cell metabolism. As applications of the expression system in C. necator H16, the growth ability on glycerol was enhanced by constitutively expressing the E. coli glpk gene-encoding for glycerol kinase. Likewise, we used the system to overcome the expression toxicity of mevalonate pathway in C. necator H16. With this system, the mevalonate-genes were successfully introduced in the host and the recombinant strains could produce about 200 mg/l mevalonate.}, language = {en} } @article{AbouzarIngebrandtPoghossianetal.2009, author = {Abouzar, Maryam H. and Ingebrandt, S. and Poghossian, Arshak and Zhang, Y. and Moritz, W. and Sch{\"o}ning, Michael Josef}, title = {Field-effect nanoplate capacitive pH sensor based on SOI structure}, series = {Semiconductor micro- and nanoelectronics : Proceedings of the Seventh International Conference , Tsakhcadzor, Armenia July 3-5 2009}, journal = {Semiconductor micro- and nanoelectronics : Proceedings of the Seventh International Conference , Tsakhcadzor, Armenia July 3-5 2009}, pages = {55 -- 58}, year = {2009}, language = {en} } @article{AbouzarIngebrandtPoghossianetal.2009, author = {Abouzar, Maryam H. and Ingebrandt, S. and Poghossian, Arshak and Zhang, Y. and Vu, X. T. and Moritz, W. and Sch{\"o}ning, Michael Josef}, title = {Nanoplate field-effect capacitive (bio-)chemical sensor array based on SOI structure}, series = {Procedia Chemistry. 1 (2009), H. 1}, journal = {Procedia Chemistry. 1 (2009), H. 1}, isbn = {1876-6196}, pages = {670 -- 673}, year = {2009}, language = {en} } @article{AbouzarPedrazaSchoeningetal.2010, author = {Abouzar, Maryam H. and Pedraza, A. M. and Sch{\"o}ning, Michael Josef and Poghossian, Arshak}, title = {Label-free DNA hybridization and denaturation detection by means of field-effect nanoplate SOI capacitors functionalized with gold nanoparticles}, series = {Procedia Engineering. 5 (2010)}, journal = {Procedia Engineering. 5 (2010)}, isbn = {1877-7058}, pages = {918 -- 921}, year = {2010}, language = {en} } @article{AbouzarPoghossianCherstvyetal.2012, author = {Abouzar, Maryam H. and Poghossian, Arshak and Cherstvy, Andrey G. and Pedraza, Angela M. and Ingebrandt, Sven and Sch{\"o}ning, Michael Josef}, title = {Label-free electrical detection of DNA by means of field-effect nanoplate capacitors: Experiments and modeling}, series = {Physica Status Solidi (a)}, volume = {209}, journal = {Physica Status Solidi (a)}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201100710}, pages = {925 -- 934}, year = {2012}, abstract = {Label-free electrical detection of consecutive deoxyribonucleic acid (DNA) hybridization/denaturation by means of an array of individually addressable field-effect-based nanoplate silicon-on-insulator (SOI) capacitors modified with gold nanoparticles (Au-NP) is investigated. The proposed device detects charge changes on Au-NP/DNA hybrids induced by the hybridization or denaturation event. DNA hybridization was performed in a high ionic-strength solution to provide a high hybridization efficiency. On the other hand, to reduce the screening of the DNA charge by counter ions and to achieve a high sensitivity, the sensor signal induced by the hybridization and denaturation events was measured in a low ionic-strength solution. High sensor signals of about 120, 90, and 80 mV were registered after the DNA hybridization, denaturation, and re-hybridization events, respectively. Fluorescence microscopy has been applied as reference method to verify the DNA immobilization, hybridization, and denaturation processes. An electrostatic charge-plane model for potential changes at the gate surface of a nanoplate field-effect sensor induced by the DNA hybridization has been developed taking into account both the Debye length and the distance of the DNA charge from the gate surface.}, language = {en} } @article{AbouzarPoghossianPedrazaetal.2011, author = {Abouzar, Maryam H. and Poghossian, Arshak and Pedraza, A. M. and Gandhi, D. and Ingebrandt, S. and Moritz, W. and Sch{\"o}ning, Michael Josef}, title = {An array of field-effect nanoplate SOI capacitors for (bio-)chemical sensing}, series = {Biosensors and Bioelectronics. 26 (2011), H. 6}, journal = {Biosensors and Bioelectronics. 26 (2011), H. 6}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0956-5663}, pages = {3023 -- 3028}, year = {2011}, language = {en} } @article{AbouzarPoghossianRazavietal.2009, author = {Abouzar, Maryam H. and Poghossian, Arshak and Razavi, A. and Williams, O. A. and Bijnens, N. and Wagner, P. and Sch{\"o}ning, Michael Josef}, title = {Characterisation of capacitive field-effect sensors with a nanocrystalline-diamond film as transducer material for multi-parameter sensing}, series = {Biosensors and Bioelectronics. 24 (2009), H. 5}, journal = {Biosensors and Bioelectronics. 24 (2009), H. 5}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0956-5663}, pages = {1298 -- 1304}, year = {2009}, language = {en} } @article{AbouzarPoghossianRazavietal.2008, author = {Abouzar, Maryam H. and Poghossian, Arshak and Razavi, Arash and Besmehn, Astrid and Bijnens, Nathalie and Williams, Oliver A. and Haenen, Ken and Wagner, Patrick and Sch{\"o}ning, Michael Josef}, title = {Penicillin detection with nanocrystalline-diamond field-effect sensor}, series = {physica status solidi (a). 205 (2008), H. 9}, journal = {physica status solidi (a). 205 (2008), H. 9}, isbn = {1862-6319}, pages = {2141 -- 2145}, year = {2008}, language = {en} } @article{AbouzarPoghossianSiqueiraetal.2010, author = {Abouzar, Maryam H. and Poghossian, Arshak and Siqueira, Jos{\´e} R. Jr. and Oliveira, Osvaldo N. Jr. and Moritz, Werner and Sch{\"o}ning, Michael Josef}, title = {Capacitive electrolyte-insulator-semiconductor structures functionalised with a polyelectrolyte/enzyme multilayer: New strategy for enhanced field-effect biosensing}, series = {Physica Status Solidi (A). 207 (2010), H. 4}, journal = {Physica Status Solidi (A). 207 (2010), H. 4}, isbn = {1862-6300}, pages = {884 -- 890}, year = {2010}, language = {en} } @article{AbouzarSchoeningPoghossianetal.2008, author = {Abouzar, Maryam H. and Sch{\"o}ning, Michael Josef and Poghossian, Arshak and Christiaens, P. and Williams, O. A. and Wagner, P. and Haenen, K.}, title = {Feldeffektsensor auf nanokristalliner Diamantbasis}, series = {Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. M{\"a}rz 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik}, journal = {Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. M{\"a}rz 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092011-5}, pages = {549 -- 558}, year = {2008}, language = {de} } @article{AbouzarWernerSchoeningetal.2011, author = {Abouzar, Maryam H. and Werner, Moritz and Sch{\"o}ning, Michael Josef and Poghossian, Arshak}, title = {Capacitance-voltage and impedance-spectroscopy characteristics of nanoplate EISOI capacitors}, series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, journal = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, publisher = {Wiley-VCH}, address = {Berlin}, isbn = {1862-6319}, pages = {1327 -- 1332}, year = {2011}, language = {en} } @article{AbulnagaPinkenburgSchiffelsetal.2013, author = {Abulnaga, El-Hussiny and Pinkenburg, Olaf and Schiffels, Johannes and E-Refai, Ahmed and Buckel, Wolfgang and Selmer, Thorsten}, title = {Effect of an Oxygen-Tolerant Bifurcating Butyryl Coenzyme A Dehydrogenase/Electron-Transferring Flavoprotein Complex from Clostridium difficile on Butyrate Production in Escherichia coli}, series = {Journal of bacteriology}, volume = {195}, journal = {Journal of bacteriology}, number = {16}, issn = {1098-5530 [E-Journal]}, pages = {3704 -- 3713}, year = {2013}, language = {en} } @phdthesis{Achtsnicht2020, author = {Achtsnicht, Stefan}, title = {Multiplex-Magnetdetektion von superparamagnetischen Beads zur Identifizierung von Trinkwasserkontaminationen}, doi = {10.18154/RWTH-2020-12052}, pages = {144 Seiten}, year = {2020}, abstract = {Die qualitative und quantitative Detektion von Zielsubstanzen innerhalb einer w{\"a}ssrigen Probe ist f{\"u}r viele Fragestellungen von Interesse, etwa bei der Detektion von Kontaminationen in Trinkwasser in Krisensituationen. Hierbei ist es nicht nur wichtig, dass Pathogene m{\"o}glichst sensitiv detektiert werden k{\"o}nnen, sondern auch, dass die Analyse schnell erfolgt, um Betroffenen im Katastrophenfall z{\"u}gig sicheres Trinkwasser zu Verf{\"u}gung stellen zu k{\"o}nnen. Da bei einem solchen Szenario nicht von einer in der N{\"a}he befindlichen funktionierenden Laborinfrastruktur ausgegangen werden kann, ist es wichtig, dass die Messung direkt vor Ort erfolgen kann. Im Rahmen dieser Arbeit wurde untersucht, ob eine derartige Schnellanalytik mithilfe von superparamagnetischen Beads (MBs) und der magnetischen Frequenzmischtechnik m{\"o}glich ist. Dabei werden die MBs mit Hilfe von prim{\"a}ren Antik{\"o}rpern an die Zielsubstanz gebunden und mit sekund{\"a}ren Antik{\"o}rpern an die Poren-Oberfl{\"a}che eines Polyethylen-Filters fixiert (Sandwich-Immunoassay). So kann die Quantifizierung der Zielsubstanz auf eine magnetische Messung der immobilisierten MB-Marker zur{\"u}ckgef{\"u}hrt werden. Die magnetische Frequenzmischtechnik basiert auf der Anregung der Probe mit Magnetfeldern zweier verschiedener Frequenzen. Die durch die nichtlineare Magnetisierungsform der superparamagnetischen MBs entstehenden Mischfrequenzen werden typischerweise mithilfe einer zweistufigen Lock-in-Detektion analysiert (analoge Demodulation), die in einem Magnetreader als Handheldger{\"a}t realisiert wurde. Zus{\"a}tzlich zu dieser Technik wurde das Prinzip der direkten Digitalisierung des gesamten Antwortsignals mit anschließender Fourier-Analyse der erzeugten Mischfrequenzen experimentell umgesetzt, um die Amplituden und Phasen mehrerer Mischfrequenzen simultan zu erfassen. Eine M{\"o}glichkeit zur Sensitivit{\"a}tssteigerung ist die magnetische Aufkonzentration, indem vor der magnetischen Analyse eine Separation der MBs aus einem gr{\"o}ßeren Probenvolumen mittels magnetischem Feldgradienten durchgef{\"u}hrt wird. Zur Charakterisierung verschiedener kommerzieller MBs hinsichtlich ihrer magnetischen Separierbarkeit wurde ein Aufbau zur Messung ihrer magnetophoretischen Beweglichkeiten realisiert und ihre Geschwindigkeiten im Gradientenfeld mikroskopisch gemessen.Da eine Probe oftmals nicht nur auf eine einzige Zielsubstanz, sondern simultan auf mehrere verschiedene Pathogene hin untersucht werden soll, wurden verschiedene Ans{\"a}tze entwickelt und getestet, die einen solchen multiparametrischen magnetischen Immunoassay erm{\"o}glichen. Einerseits wurde eine r{\"a}umliche Separation der Bindungsbereiche f{\"u}r verschiedene Zielsubstanzen realisiert, die sequentiell ausgewertet werden k{\"o}nnen. Andererseits wurde die Unterscheidung von verschiedenen Zielsubstanzen anhand der Charakteristika der an sie gebundenen, verschieden funktionalisierten MB-Typen untersucht. F{\"u}r eine solche Unterscheidung wurde zum einen die Anregefrequenz der magnetischen Frequenzmischtechnik w{\"a}hrend einer Messung variiert. Damit konnte gezeigt werden, dass sich verschiedene MB-Sorten anhand der Phase ihrer Frequenzmischsignale voneinander unterscheiden lassen. Weiterhin wurde gezeigt, dass sich der Signalverlauf einer bin{\"a}ren Mischung zweier verschiedener MB-Typen als gradueller {\"U}bergang der Verl{\"a}ufe der beiden reinen MB-L{\"o}sungen ergibt. Eine weitere Analysemethode f{\"u}r einen multiparametrischen Immunoassay besteht darin, ein zus{\"a}tzliches einstellbares statisches magnetisches Offsetfeld zu verwenden. Hierf{\"u}r wurden mehrere Aufbauten auf Basis von Permanent- und Elektromagneten simuliert, konstruiert und charakterisiert. Mithilfe von Simulationen konnte gezeigt werden, dass eine auf diesem Verfahren beruhende Unterscheidung f{\"u}r MBs mit unterschiedlichen magnetischen Partikelmomenten m{\"o}glich ist. Als direkte Anwendung des hier entwickelten Magnetreaders in Zusammenspiel mit der digitalen Demodulation wurde ein magnetischer Assay gegen die B-Untereinheit des Choleratoxins in Trinkwasser mit einem niedrigen Detektionslimit von 0,2 ng/ml demonstriert.}, language = {de} } @article{AchtsnichtNeuendorfFassbenderetal.2019, author = {Achtsnicht, Stefan and Neuendorf, Christian and Faßbender, Tobias and N{\"o}lke, Greta and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim and Schr{\"o}per, Florian}, title = {Sensitive and rapid detection of cholera toxin subunit B using magnetic frequency mixing detection}, series = {Plos One}, volume = {14}, journal = {Plos One}, number = {7}, publisher = {Plos}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0219356}, pages = {e0219356}, year = {2019}, abstract = {Cholera is a life-threatening disease caused by the cholera toxin (CT) as produced by some Vibrio cholerae serogroups. In this research we present a method which directly detects the toxin's B subunit (CTB) in drinking water. For this purpose we performed a magnetic sandwich immunoassay inside a 3D immunofiltration column. We used two different commercially available antibodies to capture CTB and for binding to superparamagnetic beads. ELISA experiments were performed to select the antibody combination. The beads act as labels for the magnetic frequency mixing detection technique. We show that the limit of detection depends on the type of magnetic beads. A nonlinear Hill curve was fitted to the calibration measurements by means of a custom-written python software. We achieved a sensitive and rapid detection of CTB within a broad concentration range from 0.2 ng/ml to more than 700 ng/ml.}, language = {en} } @article{AchtsnichtPourshahidiOffenhaeusseretal.2019, author = {Achtsnicht, Stefan and Pourshahidi, Ali Mohammad and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Multiplex detection of different magnetic beads using frequency scanning in magnetic frequency mixing technique}, series = {Sensors}, volume = {19}, journal = {Sensors}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s19112599}, pages = {13 Seiten}, year = {2019}, abstract = {In modern bioanalytical methods, it is often desired to detect several targets in one sample within one measurement. Immunological methods including those that use superparamagnetic beads are an important group of techniques for these applications. The goal of this work is to investigate the feasibility of simultaneously detecting different superparamagnetic beads acting as markers using the magnetic frequency mixing technique. The frequency of the magnetic excitation field is scanned while the lower driving frequency is kept constant. Due to the particles' nonlinear magnetization, mixing frequencies are generated. To record their amplitude and phase information, a direct digitization of the pickup-coil's signal with subsequent Fast Fourier Transformation is performed. By synchronizing both magnetic beads using frequency scanning in magnetic frequency mixing technique magnetic fields, a stable phase information is gained. In this research, it is shown that the amplitude of the dominant mixing component is proportional to the amount of superparamagnetic beads inside a sample. Additionally, it is shown that the phase does not show this behaviour. Excitation frequency scans of different bead types were performed, showing different phases, without correlation to their diverse amplitudes. Two commercially available beads were selected and a determination of their amount in a mixture is performed as a demonstration for multiplex measurements.}, language = {en} } @article{AchtsnichtSchoenenbornOffenhaeusseretal.2019, author = {Achtsnicht, Stefan and Sch{\"o}nenborn, Kristina and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim}, title = {Measurement of the magnetophoretic velocity of different superparamagnetic beads}, series = {Journal of Magnetism and Magnetic Materials}, volume = {477}, journal = {Journal of Magnetism and Magnetic Materials}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2018.10.066}, pages = {244 -- 248}, year = {2019}, abstract = {The movement of magnetic beads due to a magnetic field gradient is of great interest in different application fields. In this report we present a technique based on a magnetic tweezers setup to measure the velocity factor of magnetically actuated individual superparamagnetic beads in a fluidic environment. Several beads can be tracked simultaneously in order to gain and improve statistics. Furthermore we show our results for different beads with hydrodynamic diameters between 200 and 1000 nm from diverse manufacturers. These measurement data can, for example, be used to determine design parameters for a magnetic separation system, like maximum flow rate and minimum separation time, or to select suitable beads for fixed experimental requirements.}, language = {en} } @article{AchtsnichtToedterNiehuesetal.2019, author = {Achtsnicht, Stefan and T{\"o}dter, Julia and Niehues, Julia and Tel{\"o}ken, Matthias and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim and Schr{\"o}per, Florian}, title = {3D printed modular immunofiltration columns for frequency mixing-based multiplex magnetic immunodetection}, series = {Sensors}, volume = {19}, journal = {Sensors}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s19010148}, pages = {15 Seiten}, year = {2019}, abstract = {For performing point-of-care molecular diagnostics, magnetic immunoassays constitute a promising alternative to established enzyme-linked immunosorbent assays (ELISA) because they are fast, robust and sensitive. Simultaneous detection of multiple biomolecular targets from one body fluid sample is desired. The aim of this work is to show that multiplex magnetic immunodetection based on magnetic frequency mixing by means of modular immunofiltration columns prepared for different targets is feasible. By calculations of the magnetic response signal, the required spacing between the modules was determined. Immunofiltration columns were manufactured by 3D printing and antibody immobilization was performed in a batch approach. It was shown experimentally that two different target molecules in a sample solution could be individually detected in a single assaying step with magnetic measurements of the corresponding immobilization filters. The arrangement order of the filters and of a negative control did not influence the results. Thus, a simple and reliable approach to multi-target magnetic immunodetection was demonstrated.}, language = {en} } @article{AlmajhdiSengerAmeretal.2014, author = {Almajhdi, Fahad N. and Senger, Tilo and Amer, Haitham M. and Gissmann, Lutz and {\"O}hlschl{\"a}ger, Peter}, title = {Design of a highly effective therapeutic HPV16 E6/E7-specific DNA vaccine: optimization by different ways of sequence rearrangements (Shuffling)}, series = {PLOS one}, volume = {11}, journal = {PLOS one}, number = {9}, publisher = {PLOS}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0113461}, pages = {e113461}, year = {2014}, abstract = {Persistent infection with the high-risk Human Papillomavirus type 16 (HPV 16) is the causative event for the development of cervical cancer and other malignant tumors of the anogenital tract and of the head and neck. Despite many attempts to develop therapeutic vaccines no candidate has entered late clinical trials. An interesting approach is a DNA based vaccine encompassing the nucleotide sequence of the E6 and E7 viral oncoproteins. Because both proteins are consistently expressed in HPV infected cells they represent excellent targets for immune therapy. Here we report the development of 8 DNA vaccine candidates consisting of differently rearranged HPV-16 E6 and E7 sequences within one molecule providing all naturally occurring epitopes but supposedly lacking transforming activity. The HPV sequences were fused to the J-domain and the SV40 enhancer in order to increase immune responses. We demonstrate that one out of the 8 vaccine candidates induces very strong cellular E6- and E7- specific cellular immune responses in mice and, as shown in regression experiments, efficiently controls growth of HPV 16 positive syngeneic tumors. This data demonstrates the potential of this vaccine candidate to control persistent HPV 16 infection that may lead to malignant disease. It also suggests that different sequence rearrangements influence the immunogenecity by an as yet unknown mechanism.}, language = {en} } @article{AridaAlhaddadSchoening2011, author = {Arida, Hassan A. and Al-haddad, Ameera and Sch{\"o}ning, Michael Josef}, title = {New Solid-State Organic Membrane Based Lead-Selective Micro-Electrode}, series = {International Journal of Electrochemical Science. 6 (2011), H. 9}, journal = {International Journal of Electrochemical Science. 6 (2011), H. 9}, isbn = {1452-3981}, pages = {3858 -- 3867}, year = {2011}, language = {en} }