TY - JOUR A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Chemical and biological field-effect sensors for liquids – a status report JF - Handbook of biosensors and biochips / ed. Robert S. Marks ... Bd. 1 Y1 - 2007 SN - 978-0-470-01905-4 SP - 395 EP - 412 PB - Wiley CY - Chichester ER - TY - JOUR A1 - Knobbe, D.-T. A1 - Schöning, Michael Josef A1 - Poghossian, Arshak A1 - Mourzina, Y. T1 - Charakterisierung von kapazitiven EMISSensoren mittels Impedanzspektroskopie, Kapazitäts-Spannungs- und Konstant-Kapazitäts-Messung JF - Sensoren und Messsysteme 2004 : Tagung Ludwigsburg, 15. und 16. März 2004 / VDI-VDE-Gesellschaft Mess- und Automatisierungstechnik Y1 - 2004 SN - 3-18-091829-2 N1 - Auch erschienen als: VDI-Berichte ; 1829 SP - 851 EP - 854 PB - VDI CY - Düsseldorf ER - TY - JOUR A1 - Schusser, Sebastian A1 - Poghossian, Arshak A1 - Bäcker, Matthias A1 - Leinhos, Marcel A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Characterization of biodegradable polymers with capacitive field-effect sensors JF - Sensors and actuators B: Chemical N2 - In vitro studies of the degradation kinetic of biopolymers are essential for the design and optimization of implantable biomedical devices. In the presented work, a field-effect capacitive sensor has been applied for the real-time and in situ monitoring of degradation processes of biopolymers for the first time. The polymer-covered field-effect sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by degradation processes. The feasibility of this approach has been experimentally proven by using the commercially available biomedical polymer poly(D,L-lactic acid) (PDLLA) as a model system. PDLLA films of different thicknesses were deposited on the Ta₂O₅-gate surface of the field-effect structure from a polymer solution by means of spin-coating method. The polymer-modified field-effect sensors have been characterized by means of capacitance–voltage and impedance-spectroscopy method. The degradation of the PDLLA was accelerated by changing the degradation medium from neutral (pH 7.2) to alkaline (pH 9) condition, resulting in drastic changes in the capacitance and impedance spectra of the polymer-modified field-effect sensor. KW - Impedance spectroscopy KW - C–V method KW - Real-time monitoring KW - Poly(d,l-lacticacid) KW - (Bio)degradation KW - Field-effect sensor Y1 - 2012 U6 - https://doi.org/10.1016/j.snb.2012.07.099 SN - 0925-4005 N1 - Part of special issue "Selected Papers from the 14th International Meeting on Chemical Sensors" VL - 187 SP - 2 EP - 7 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schroth, P. A1 - Lüth, H. A1 - Hummel, Hans E. A1 - Schütz, S. A1 - Schöning, Michael Josef T1 - Characterising an insect antenna as a receptor for a biosensor by means of impedance spectroscopy JF - Scaling down in electrochemistry : electrochemical micro- and nanosystem technology ; proceedings of the 3rd International Symposium on Electrochemical Microsystem Technologies, Garmisch-Patenkirchen, Germany, 11 - 15 September 2000 / ed. by J. W. Schultz Y1 - 2001 SN - 0-08-044014-2 SP - 293 EP - 297 PB - Elsevier [u.a.] CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Kirchner, Patrick A1 - Reisert, Steffen A1 - Pütz, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Characterisation of polymeric materials as passivation layer for calorimetric H2O2 gas sensors JF - Physica Status Solidi (a) N2 - Calorimetric gas sensors for monitoring the H₂O₂ concentration at elevated temperatures in industrial sterilisation processes have been presented in previous works. These sensors are built up in form of a differential set-up of a catalytically active and passive temperature-sensitive structure. Although, various types of catalytically active dispersions have been studied, the passivation layer has to be established and therefore, chemically as well as physically characterised. In the present work, fluorinated ethylene propylene (FEP), perfluoralkoxy (PFA) and epoxy-based SU-8 photoresist as temperature-stable polymeric materials have been investigated for sensor passivation in terms of their chemical inertness against H₂O₂, their hygroscopic properties as well as their morphology. The polymeric materials were deposited via spin-coating on the temperature-sensitive structure, wherein spin-coated FEP and PFA show slight agglomerates. However, they possess a low absorption of humidity due to their hydrophobic surface, whereas the SU-8 layer has a closed surface but shows a slightly higher absorption of water. All of them were inert against gaseous H₂O₂ during the characterisation in H₂O₂ atmosphere that demonstrates their suitability as passivation layer for calorimetric H₂O₂ gas sensors. Y1 - 2012 U6 - https://doi.org/10.1002/pssa.201100773 SN - 1862-6319 VL - 209 IS - 5 SP - 859 EP - 863 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Abouzar, Maryam H. A1 - Poghossian, Arshak A1 - Razavi, A. A1 - Williams, O. A. A1 - Bijnens, N. A1 - Wagner, P. A1 - Schöning, Michael Josef T1 - Characterisation of capacitive field-effect sensors with a nanocrystalline-diamond film as transducer material for multi-parameter sensing JF - Biosensors and Bioelectronics. 24 (2009), H. 5 Y1 - 2009 SN - 0956-5663 N1 - Selected Papers from the Tenth World Congress on Biosensors Shangai, China, May 14-16, 2008 ; Zeitschrift früher u.d.T. : Biosensors SP - 1298 EP - 1304 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Reisert, Steffen A1 - Geissler, Hanno A1 - Flörke, Rudolf A1 - Weiler, Christian A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Characterisation of aseptic sterilisation processes using an electronic nose JF - International journal of nanotechnology Y1 - 2013 SN - 1475-7435 (Print) 7141-8151 (Online) VL - Vol. 10 IS - No. 5-7 SP - 470 EP - 484 PB - Inderscience Enterprises CY - Genève ER - TY - JOUR A1 - Haeger, Gerrit A1 - Wirges, Jessika A1 - Tanzmann, Nicole A1 - Oyen, Sven A1 - Jolmes, Tristan A1 - Jaeger, Karl-Erich A1 - Schörken, Ulrich A1 - Bongaerts, Johannes A1 - Siegert, Petra T1 - Chaperone assisted recombinant expression of a mycobacterial aminoacylase in Vibrio natriegens and Escherichia coli capable of N-lauroyl-L-amino acid synthesis JF - Microbial Cell Factories N2 - Background Aminoacylases are highly promising enzymes for the green synthesis of acyl-amino acids, potentially replacing the environmentally harmful Schotten-Baumann reaction. Long-chain acyl-amino acids can serve as strong surfactants and emulsifiers, with application in cosmetic industries. Heterologous expression of these enzymes, however, is often hampered, limiting their use in industrial processes. Results We identified a novel mycobacterial aminoacylase gene from Mycolicibacterium smegmatis MKD 8, cloned and expressed it in Escherichia coli and Vibrio natriegens using the T7 overexpression system. The recombinant enzyme was prone to aggregate as inclusion bodies, and while V. natriegens Vmax™ could produce soluble aminoacylase upon induction with isopropyl β-d-1-thiogalactopyranoside (IPTG), E. coli BL21 (DE3) needed autoinduction with lactose to produce soluble recombinant protein. We successfully conducted a chaperone co-expression study in both organisms to further enhance aminoacylase production and found that overexpression of chaperones GroEL/S enhanced aminoacylase activity in the cell-free extract 1.8-fold in V. natriegens and E. coli. Eventually, E. coli ArcticExpress™ (DE3), which co-expresses cold-adapted chaperonins Cpn60/10 from Oleispira antarctica, cultivated at 12 °C, rendered the most suitable expression system for this aminoacylase and exhibited twice the aminoacylase activity in the cell-free extract compared to E. coli BL21 (DE3) with GroEL/S co-expression at 20 °C. The purified aminoacylase was characterized based on hydrolytic activities, being most stable and active at pH 7.0, with a maximum activity at 70 °C, and stability at 40 °C and pH 7.0 for 5 days. The aminoacylase strongly prefers short-chain acyl-amino acids with smaller, hydrophobic amino acid residues. Several long-chain amino acids were fairly accepted in hydrolysis as well, especially N-lauroyl-L-methionine. To initially evaluate the relevance of this aminoacylase for the synthesis of N-acyl-amino acids, we demonstrated that lauroyl-methionine can be synthesized from lauric acid and methionine in an aqueous system. Conclusion Our results suggest that the recombinant enzyme is well suited for synthesis reactions and will thus be further investigated. KW - Acyl-amino acids KW - Inclusion bodies KW - Chaperone co-expression KW - Vibrio natriegens KW - Aminoacylase Y1 - 2023 U6 - https://doi.org/10.1186/s12934-023-02079-1 SN - 1475-2859 N1 - Corresponding author: Petra Siegert IS - 22 SP - Article number: 77 (2023) PB - Springer Nature ER - TY - JOUR A1 - Kloock, Joachim P. A1 - Mourzina, Y.G. A1 - Yoshinobu, T. A1 - Schubert, J. A1 - Schöning, Michael Josef T1 - Chalkogenidglassensoren für die Schwermetallanalytik JF - Sensoren und Mess-Systeme : Vorträge der 11. ITG/GMA-Fachtagung vom 11. bis 12. März 2002 in Ludwigsburg / Veranst.: Informationstechnische Gesellschaft im VDE (ITG) ... Wiss. Tagungsleitung: C. D. Kohl .... Y1 - 2002 SN - 3-8007-2675-0 N1 - Sensoren und Mess-Systeme 2002 SP - 395 EP - 398 PB - VDE-Verl. CY - Berlin [u.a.] ER - TY - JOUR A1 - Handtke, Stefan A1 - Volland, Sonja A1 - Methling, Karen A1 - Albrecht, Dirk A1 - Becher, Dörte A1 - Nehls, Jenny A1 - Bongaerts, Johannes A1 - Maurer, Karl-Heinz A1 - Lalk, Michael A1 - Liesegang, Heiko A1 - Voigt, Birgit A1 - Daniel, Rolf A1 - Hecker, Michael T1 - Cell physiology of the biotechnological relevant bacterium Bacillus pumilus - An omics-based approach JF - Journal of Biotechnology N2 - Members of the species Bacillus pumilus get more and more in focus of the biotechnological industry as potential new production strains. Based on exoproteome analysis, B. pumilus strain Jo2, possessing a high secretion capability, was chosen for an omics-based investigation. The proteome and metabolome of B. pumilus cells growing either in minimal or complex medium was analyzed. In total, 1542 proteins were identified in growing B. pumilus cells, among them 1182 cytosolic proteins, 297 membrane and lipoproteins and 63 secreted proteins. This accounts for about 43% of the 3616 proteins encoded in the B. pumilus Jo2 genome sequence. By using GC–MS, IP-LC/MS and H NMR methods numerous metabolites were analyzed and assigned to reconstructed metabolic pathways. In the genome sequence a functional secretion system including the components of the Sec- and Tat-secretion machinery was found. Analysis of the exoproteome revealed secretion of about 70 proteins with predicted secretion signals. In addition, selected production-relevant genome features such as restriction modification systems and NRPS clusters of B. pumilus Jo2 are discussed. Y1 - 2014 U6 - https://doi.org/10.1016/j.jbiotec.2014.08.028 SN - 1873-4863 (E-Journal); 0168-1656 (Print) IS - 192(A) SP - 204 EP - 214 PB - Elsevier CY - Amsterdam ER -