@article{PourshahidiAchtsnichtNambipareecheeetal.2021,
  author    = {Pourshahidi, Ali Mohammad and Achtsnicht, Stefan and Nambipareechee, Mrinal Murali and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim},
  title     = {Multiplex detection of magnetic beads using offset field dependent frequency mixing magnetic detection},
  series = {Sensors},
  volume    = {21},
  journal   = {Sensors},
  number    = {17},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s21175859},
  pages     = {16 Seiten},
  year      = {2021},
  abstract  = {Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic beads can be distinguished according to their frequency mixing response to a two-frequency magnetic excitation at different static magnetic offset fields. We recorded the offset field dependent FMMD response of two different particle types at frequencies ƒ₁ + n⋅ƒ₂, n = 1, 2, 3, 4 with ƒ₁ = 30.8 kHz and ƒ₂ = 63 Hz. Their signals were clearly distinguishable by the locations of the extremes and zeros of their responses. Binary mixtures of the two particle types were prepared with different mixing ratios. The mixture samples were analyzed by determining the best linear combination of the two pure constituents that best resembled the measured signals of the mixtures. Using a quadratic programming algorithm, the mixing ratios could be determined with an accuracy of greater than 14\%. If each particle type is functionalized with a different antibody, multiplex detection of two different analytes becomes feasible.},
  language  = {en}
}
@article{PourshahidiAchtsnichtOffenhaeusseretal.2022,
  author    = {Pourshahidi, Ali Mohammad and Achtsnicht, Stefan and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim},
  title     = {Frequency Mixing Magnetic Detection Setup Employing Permanent Ring Magnets as a Static Offset Field Source},
  series = {Sensors},
  volume    = {22},
  journal   = {Sensors},
  number    = {22},
  editor    = {Offenh{\"a}usser, Andreas},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s22228776},
  pages     = {12 Seiten},
  year      = {2022},
  abstract  = {Frequency mixing magnetic detection (FMMD) has been explored for its applications in fields of magnetic biosensing, multiplex detection of magnetic nanoparticles (MNP) and the determination of core size distribution of MNP samples. Such applications rely on the application of a static offset magnetic field, which is generated traditionally with an electromagnet. Such a setup requires a current source, as well as passive or active cooling strategies, which directly sets a limitation based on the portability aspect that is desired for point of care (POC) monitoring applications. In this work, a measurement head is introduced that involves the utilization of two ring-shaped permanent magnets to generate a static offset magnetic field. A steel cylinder in the ring bores homogenizes the field. By variation of the distance between the ring magnets and of the thickness of the steel cylinder, the magnitude of the magnetic field at the sample position can be adjusted. Furthermore, the measurement setup is compared to the electromagnet offset module based on measured signals and temperature behavior.},
  language  = {en}
}
@article{PourshahidiEngelmannOffenhaeusseretal.2022,
  author    = {Pourshahidi, Ali Mohammad and Engelmann, Ulrich M. and Offenh{\"a}usser, Andreas and Krause, Hans-Joachim},
  title     = {Resolving ambiguities in core size determination of magnetic nanoparticles from magnetic frequency mixing data},
  series = {Journal of Magnetism and Magnetic Materials},
  volume    = {563},
  journal   = {Journal of Magnetism and Magnetic Materials},
  number    = {In progress, Art. No. 169969},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0304-8853},
  doi       = {10.1016/j.jmmm.2022.169969},
  year      = {2022},
  abstract  = {Frequency mixing magnetic detection (FMMD) has been widely utilized as a measurement technique in magnetic immunoassays. It can also be used for the characterization and distinction (also known as "colourization") of different types of magnetic nanoparticles (MNPs) based on their core sizes. In a previous work, it was shown that the large particles contribute most of the FMMD signal. This leads to ambiguities in core size determination from fitting since the contribution of the small-sized particles is almost undetectable among the strong responses from the large ones. In this work, we report on how this ambiguity can be overcome by modelling the signal intensity using the Langevin model in thermodynamic equilibrium including a lognormal core size distribution fL(dc,d0,σ) fitted to experimentally measured FMMD data of immobilized MNPs. For each given median diameter d0, an ambiguous amount of best-fitting pairs of parameters distribution width σ and number of particles Np with R2 > 0.99 are extracted. By determining the samples' total iron mass, mFe, with inductively coupled plasma optical emission spectrometry (ICP-OES), we are then able to identify the one specific best-fitting pair (σ, Np) one uniquely. With this additional externally measured parameter, we resolved the ambiguity in core size distribution and determined the parameters (d0, σ, Np) directly from FMMD measurements, allowing precise MNPs sample characterization.},
  language  = {en}
}
@article{RabehiGarlanAchtsnichtetal.2018,
  author    = {Rabehi, Amine and Garlan, Benjamin and Achtsnicht, Stefan and Krause, Hans-Joachim and Offenh{\"a}usser, Andreas and Ngo, Kieu and Neveu, Sophie and Graff-Dubois, Stephanie and Kokabi, Hamid},
  title     = {Magnetic detection structure for Lab-on-Chip applications based on the frequency mixing technique},
  series = {Sensors},
  volume    = {18},
  journal   = {Sensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s18061747},
  pages     = {14 Seiten},
  year      = {2018},
  abstract  = {A magnetic frequency mixing technique with a set of miniaturized planar coils was investigated for use with a completely integrated Lab-on-Chip (LoC) pathogen sensing system. The system allows the detection and quantification of superparamagnetic beads. Additionally, in terms of magnetic nanoparticle characterization ability, the system can be used for immunoassays using the beads as markers. Analytical calculations and simulations for both excitation and pick-up coils are presented; the goal was to investigate the miniaturization of simple and cost-effective planar spiral coils. Following these calculations, a Printed Circuit Board (PCB) prototype was designed, manufactured, and tested for limit of detection, linear response, and validation of theoretical concepts. Using the magnetic frequency mixing technique, a limit of detection of 15 µg/mL of 20 nm core-sized nanoparticles was achieved without any shielding.},
  language  = {en}
}
@article{RachingerBauchStrittmatteretal.2013,
  author    = {Rachinger, Michael and Bauch, Melanie and Strittmatter, Axel and Bongaerts, Johannes and Evers, Stefan and Maurer, Karl-Heinz and Daniel, Rolf and Liebl, Wolfgang and Liesegang, Heiko and Ehrenreich, Armin},
  title     = {Size unlimited markerless deletions by a transconjugative plasmid-system in Bacillus licheniformis},
  series = {Journal of biotechnology},
  volume    = {Vol. 164},
  journal   = {Journal of biotechnology},
  number    = {Iss. 4},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4863 (E-Journal); 0168-1656 (Print)},
  pages     = {365 -- 369},
  year      = {2013},
  language  = {en}
}
@article{ReisertGeisslerFlorkeetal.2011,
  author    = {Reisert, Steffen and Geissler, H. and Florke, R. and Wagner, P. and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Controlling aseptic sterilization processes by means of a multi-sensor system},
  publisher = {IEEE},
  address   = {New York},
  pages     = {18 -- 22},
  year      = {2011},
  language  = {en}
}
@article{ReisertGeisslerWeileretal.2015,
  author    = {Reisert, Steffen and Geissler, H. and Weiler, C. and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Multiple sensor-type system for monitoring the microbicidal effectiveness of aseptic sterilisation processes},
  series = {Food control},
  volume    = {47},
  journal   = {Food control},
  issn      = {1873-7129 (E-Journal); 0956-7135 (Print)},
  doi       = {10.1016/j.foodcont.2014.07.063},
  pages     = {615 -- 622},
  year      = {2015},
  abstract  = {The present work describes a novel multiple sensor-type system for the real-time analysis of aseptic sterilisation processes employing gaseous hydrogen peroxide (H2O2) as a sterilant. The inactivation kinetics of Bacillus atrophaeus by gaseous H2O2 have been investigated by means of a methodical calibration experiment, taking into account the process variables H2O2 concentration, humidity and gas temperature. It has been found that the microbicidal effectiveness at H2O2 concentrations above 2\% v/v is largely determined by the concentration itself, while at lower H2O2 concentrations, the gas temperature and humidity play a leading role. Furthermore, the responses of different types of gas sensors towards the influencing factors of the sterilisation process have been analysed within the same experiment. Based on a correlation established between the inactivation kinetics and the sensor responses, a calorimetric H2O2 sensor and a metal-oxide semiconductor (MOX) sensor have been identified as possible candidates for monitoring the microbicidal effectiveness of aseptic sterilisation processes employing gaseous H2O2. Therefore, two linear models that describe the relationship between sensor response and microbicidal effectiveness have been proposed.},
  language  = {en}
}
@article{ReisertGeisslerFloerkeetal.2011,
  author    = {Reisert, Steffen and Geissler, Hanno and Fl{\"o}rke, Rudolf and N{\"a}ther, Niko and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Towards a multi-sensor system for the evaluation of aseptic processes employing hydrogen peroxide vapour (H2O2)},
  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},
  address   = {Weinheim},
  isbn      = {1862-6319},
  pages     = {1351 -- 1356},
  year      = {2011},
  language  = {en}
}
@article{ReisertGeisslerFloerkeetal.2013,
  author    = {Reisert, Steffen and Geissler, Hanno and Fl{\"o}rke, Rudolf and Weiler, Christian and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Characterisation of aseptic sterilisation processes using an electronic nose},
  series = {International journal of nanotechnology},
  volume    = {Vol. 10},
  journal   = {International journal of nanotechnology},
  number    = {No. 5-7},
  publisher = {Inderscience Enterprises},
  address   = {Gen{\`e}ve},
  issn      = {1475-7435 (Print) 7141-8151 (Online)},
  pages     = {470 -- 484},
  year      = {2013},
  language  = {en}
}
@article{ReisertHenkelSchneideretal.2009,
  author    = {Reisert, Steffen and Henkel, H. and Schneider, A. and Sch{\"a}fer, D. and Friedrich, P. and Berger, J. and Sch{\"o}ning, Michael Josef},
  title     = {Entwicklung eines Handheld-Sensorsystems f{\"u}r die „On-line"-Messung der H2O2-Konzentration in aseptischen Entkeimungsprozessen},
  series = {9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]},
  journal   = {9. Dresdner Sensor-Symposium : Dresden, 07.-09. Dezember 2009 / Gerlach, Gerald ; Hauptmann, Peter [Hrsg.]},
  publisher = {TUDpress},
  address   = {Dresden},
  isbn      = {978-3-941298-44-6},
  pages     = {285 -- 288},
  year      = {2009},
  language  = {de}
}
@article{ReisertHenkelSchneideretal.2010,
  author    = {Reisert, Steffen and Henkel, Hartmut and Schneider, Andreas and Sch{\"a}fer, Daniel and Friedrich, Peter and Berger, J{\"o}rg and Sch{\"o}ning, Michael Josef},
  title     = {Development of a handheld sensor system for the online measurement of hydrogen peroxide in aseptic filling systems},
  series = {Physica Status Solidi (A). 207 (2010), H. 4},
  journal   = {Physica Status Solidi (A). 207 (2010), H. 4},
  isbn      = {1862-6300},
  pages     = {913 -- 918},
  year      = {2010},
  language  = {en}
}
@article{ReisertSchneiderGeissleretal.2013,
  author    = {Reisert, Steffen and Schneider, Benno and Geissler, Hanno and Gompel, Matthias van and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Multi-sensor chip for the investigation of different types of metal oxides for the detection of H2O2 in the ppm range},
  series = {physica status solidi (a)},
  volume    = {210},
  journal   = {physica status solidi (a)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  pages     = {898 -- 904},
  year      = {2013},
  abstract  = {In this work, a multi-sensor chip for the investigation of the sensing properties of different types of metal oxides towards hydrogen peroxide in the ppm range is presented. The fabrication process and physical characterization of the multi-sensor chip are described. Pure SnO2 and WO3 as well as Pd- and Pt-doped SnO2 films are characterized in terms of their sensitivity to H2O2. The sensing films have been prepared by drop-coating of water-dispensed nano-powders. A physical characterization, including scanning electron microscopy and X-ray diffraction analysis of the deposited metal-oxide films, was done. From the measurements in hydrogen peroxide atmosphere, it could be shown, that all of the tested metal oxide films are suitable for the detection of H2O2 in the ppm range. The highest sensitivity and reproducibility was achieved using Pt-doped SnO2. Calibration plot of a SnO2, WO3, Pt-, and Pd-doped SnO2 gas sensor for H2O2 concentrations in the ppm range.},
  language  = {en}
}
@article{RibitschHeumannKarletal.2012,
  author    = {Ribitsch, D. and Heumann, S. and Karl, W. and Gerlach, J. and Leber, R. and Birner-Gruenberger, R. and Gruber, K. and Eiteljoerg, I. and Remler, P. and Siegert, Petra and Lange, J. and Maurer, Karl-Heinz and Berg, G. and Guebitz, G. M. and Schwab, H.},
  title     = {Extracellular serine proteases from Stenotrophomonas maltophilia: Screening, isolation and heterologous expression in E. coli},
  series = {Journal of biotechnology},
  volume    = {157},
  journal   = {Journal of biotechnology},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4863 (E-Journal); 0168-1656 (Print)},
  doi       = {10.1016/j.jbiotec.2011.09.025},
  pages     = {140 -- 147},
  year      = {2012},
  abstract  = {A large strain collection comprising antagonistic bacteria was screened for novel detergent proteases. Several strains displayed protease activity on agar plates containing skim milk but were inactive in liquid media. Encapsulation of cells in alginate beads induced protease production. Stenotrophomonas maltophilia emerged as best performer under washing conditions. For identification of wash-active proteases, four extracellular serine proteases called StmPr1, StmPr2, StmPr3 and StmPr4 were cloned. StmPr2 and StmPr4 were sufficiently overexpressed in E. coli. Expression of StmPr1 and StmPr3 resulted in unprocessed, insoluble protein. Truncation of most of the C-terminal domain which has been identified by enzyme modeling succeeded in expression of soluble, active StmPr1 but failed in case of StmPr3. From laundry application tests StmPr2 turned out to be a highly wash-active protease at 45 °C. Specific activity of StmPr2 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 17 ± 2 U/mg. In addition we determined the kinetic parameters and cleavage preferences of protease StmPr2.},
  language  = {en}
}
@article{RibitschKarlBirnerGruenbergeretal.2010,
  author    = {Ribitsch, D. and Karl, W. and Birner-Gruenberger, R. and Gruber, K. and Eiteljoerg, I. and Remler, P. and Wieland, S. and Siegert, Petra and Maurer, Karl-Heinz and Schwab, H.},
  title     = {C-terminal truncation of a metagenome-derived detergent protease for effective expression in E. coli},
  series = {Journal of biotechnology},
  volume    = {150},
  journal   = {Journal of biotechnology},
  number    = {3},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4863 (E-Journal); 0168-1656 (Print)},
  doi       = {10.1016/j.jbiotec.2010.09.947},
  pages     = {408 -- 416},
  year      = {2010},
  abstract  = {Recently, a new alkaline protease named HP70 showing highest homology to extracellular serine proteases of Stenotrophomonas maltophilia and Xanthomonas campestris was found in the course of a metagenome screening for detergent proteases (Niehaus et al., submitted for publication). Attempts to efficiently express the enzyme in common expression hosts had failed. This study reports on the realization of overexpression in Escherichia coli after structural modification of HP70. Modelling of HP70 resulted in a two-domain structure, comprising the catalytic domain and a C-terminal domain which includes about 100 amino acids. On the basis of the modelled structure the enzyme was truncated by deletion of most of the C-terminal domain yielding HP70-C477. This structural modification allowed effective expression of active enzyme using E. coli BL21-Gold as the host. Specific activity of HP70-C477 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 30 ± 5 U/mg compared to 8 ± 1 U/mg of the native enzyme. HP70-C477 was most active at 40 °C and pH 7-11; these conditions are prerequisite for a potential application as detergent enzyme. Determination of kinetic parameters at 40 °C and pH = 9.5 resulted in KM = 0.23 ± 0.01 mM and kcat = 167.5 ± 3.6 s⁻¹. MS-analysis of peptide fragments obtained from incubation of HP70 and HP70-C477 with insulin B indicated that the C-terminal domain influences the cleavage preferences of the enzyme. Washing experiments confirmed the high potential of HP70-C477 as detergent protease.},
  language  = {en}
}
@article{RiemerSchrothSchuetzetal.2000,
  author    = {Riemer, A. and Schroth, P. and Sch{\"u}tz, S. and Hummel, Hans E. and L{\"u}th, H. and Kohl, C.-D. and Sch{\"o}ning, Michael Josef},
  title     = {The future of fire detection: Biological sensors? - Die Zukunft der Brandgassensorik: Biologische Sensoren?},
  series = {Gassensorik in der Brandmeldetechnik : [VdS-Fachtagung, am 15. und 16. November 2000 in K{\"o}ln] = Gas sensors for fire detection / VdS Schadenverh{\"u}tung},
  journal   = {Gassensorik in der Brandmeldetechnik : [VdS-Fachtagung, am 15. und 16. November 2000 in K{\"o}ln] = Gas sensors for fire detection / VdS Schadenverh{\"u}tung},
  publisher = {VdS Schadenverh{\"u}tung},
  address   = {K{\"o}ln},
  pages     = {1 -- 7},
  year      = {2000},
  language  = {en}
}
@inproceedings{RoderburgSchoening2008,
  author    = {Roderburg, Katharina and Sch{\"o}ning, Michael Josef},
  title     = {1. Graduierten-Tagung : 9. September 2008 / [Hrsg.: K. Roderburg ; M. J. Sch{\"o}ning]},
  organization    = {FH Aachen, University of Applied Sciences / Graduiertentagung <1, 2008>},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:a96-opus-3125},
  year      = {2008},
  abstract  = {Tagungsband der Graduiertentagung der FH Aachen, in dem Doktorandinnen und Doktoranden und ihre Forschungsbereiche vorgestellt werden},
  subject      = {Aachen / Fachhochschule Aachen},
  language  = {de}
}
@article{RodriguesMoraisNordietal.2018,
  author    = {Rodrigues, Raul T. and Morais, Paulo V. and Nordi, Cristina S. F. and Sch{\"o}ning, Michael Josef and Siqueira Jr., Jos{\´e} R. and Caseli, Luciano},
  title     = {Carbon Nanotubes and Algal Polysaccharides To Enhance the Enzymatic Properties of Urease in Lipid Langmuir-Blodgett Films},
  series = {Langmuir},
  volume    = {34},
  journal   = {Langmuir},
  number    = {9},
  publisher = {ACS Publications},
  address   = {Washington, DC},
  issn      = {1520-5827},
  doi       = {10.1021/acs.langmuir.7b04317},
  pages     = {3082 -- 3093},
  year      = {2018},
  abstract  = {Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air-water interface were investigated by surface pressure-area isotherms, surface potential-area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte-insulator-semiconductor (EIS) devices, through the Langmuir-Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV-vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance-voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications.},
  language  = {en}
}
@article{RolkaPoghossianSchoening2004,
  author    = {Rolka, David and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Integration of a capacitive EIS sensor into a FIA system for pH and penicillin determination},
  series = {Sensors. 4 (2004)},
  journal   = {Sensors. 4 (2004)},
  isbn      = {1424-8220},
  pages     = {84 -- 94},
  year      = {2004},
  language  = {en}
}
@article{RosenauerOberstLitvinovetal.2000,
  author    = {Rosenauer, A. and Oberst, W. and Litvinov, D. and Gerthsen, D. and F{\"o}rster, Arnold and Schmidt, R.},
  title     = {Structural and Chemical Investigation of In-0.6Ga0.4As Stranski-Krastanow Layers Burried in GaAs by Transmission Electron Microscopy},
  series = {Physical Review B. 61 (2000), H. 12},
  journal   = {Physical Review B. 61 (2000), H. 12},
  isbn      = {1095-3795},
  pages     = {8276 -- 8288},
  year      = {2000},
  language  = {en}
}
@article{RoehlenPilasDahmenetal.2018,
  author    = {R{\"o}hlen, Desiree and Pilas, Johanna and Dahmen, Markus and Keusgen, Michael and Selmer, Thorsten and Sch{\"o}ning, Michael Josef},
  title     = {Toward a Hybrid Biosensor System for Analysis of Organic and Volatile Fatty Acids in Fermentation Processes},
  series = {Frontiers in Chemistry},
  journal   = {Frontiers in Chemistry},
  number    = {6},
  publisher = {Frontiers},
  address   = {Lausanne},
  doi       = {10.3389/fchem.2018.00284},
  pages     = {Artikel 284},
  year      = {2018},
  abstract  = {Monitoring of organic acids (OA) and volatile fatty acids (VFA) is crucial for the control of anaerobic digestion. In case of unstable process conditions, an accumulation of these intermediates occurs. In the present work, two different enzyme-based biosensor arrays are combined and presented for facile electrochemical determination of several process-relevant analytes. Each biosensor utilizes a platinum sensor chip (14 × 14 mm²) with five individual working electrodes. The OA biosensor enables simultaneous measurement of ethanol, formate, d- and l-lactate, based on a bi-enzymatic detection principle. The second VFA biosensor provides an amperometric platform for quantification of acetate and propionate, mediated by oxidation of hydrogen peroxide. The cross-sensitivity of both biosensors toward potential interferents, typically present in fermentation samples, was investigated. The potential for practical application in complex media was successfully demonstrated in spiked sludge samples collected from three different biogas plants. Thereby, the results obtained by both of the biosensors were in good agreement to the applied reference measurements by photometry and gas chromatography, respectively. The proposed hybrid biosensor system was also used for long-term monitoring of a lab-scale biogas reactor (0.01 m³) for a period of 2 months. In combination with typically monitored parameters, such as gas quality, pH and FOS/TAC (volatile organic acids/total anorganic carbonate), the amperometric measurements of OA and VFA concentration could enhance the understanding of ongoing fermentation processes.},
  language  = {en}
}
@article{RoehlenPilasSchoeningetal.2017,
  author    = {R{\"o}hlen, Desiree and Pilas, Johanna and Sch{\"o}ning, Michael Josef and Selmer, Thorsten},
  title     = {Development of an amperometric biosensor platform for the combined determination of l-Malic, Fumaric, and l-Aspartic acid},
  series = {Applied Biochemistry and Biotechnology},
  volume    = {183},
  journal   = {Applied Biochemistry and Biotechnology},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1559-0291},
  doi       = {10.1007/s12010-017-2578-1},
  pages     = {566 -- 581},
  year      = {2017},
  abstract  = {Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD+) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM-1 (L-malate biosensor) and 0.4 μA mM-1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM-1. The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.},
  language  = {en}
}
@article{SabitovaEbertLenzetal.2013,
  author    = {Sabitova, A. and Ebert, Ph. and Lenz, A. and Schaafhausen, S. and Ivanova, L. and D{\"a}hne, M. and Hoffmann, A. and Dunin-Borkowski, R. E. and F{\"o}rster, Arnold and Grandidier, B. and Eisele, H.},
  title     = {Intrinsic bandgap of cleaved ZnO(112¯0) surfaces},
  series = {Applied physics letters},
  volume    = {Vol. 102},
  journal   = {Applied physics letters},
  issn      = {1077-3118 (E-Journal); 0003-6951 (Print)},
  pages     = {021608},
  year      = {2013},
  language  = {en}
}
@article{ScheeleBongaertsMaureretal.2009,
  author    = {Scheele, S. and Bongaerts, Johannes and Maurer, K.-H. and Freudl, R.},
  title     = {Sekretion einer Kofaktor-haltigen Oxidase durch Corynebacterium glutamicum},
  series = {Chemie - Ingenieur - Technik (CIT)},
  volume    = {Vol. 81},
  journal   = {Chemie - Ingenieur - Technik (CIT)},
  number    = {Iss. 8},
  issn      = {1522-2640 (E-Journal); 0009-286X (Print)},
  pages     = {1309},
  year      = {2009},
  language  = {de}
}
@article{ScheeleOertelBongaertsetal.2013,
  author    = {Scheele, Sandra and Oertel, Dan and Bongaerts, Johannes and Evers, Stefan and Hellmuth, Hendrik and Maurer, Karl-Heinz and Bott, Michael and Freudl, Roland},
  title     = {Secretory production of an FAD cofactor-containing cytosolic enzyme (sorbitol-xylitol oxidase from Streptomyces coelicolor) using the twin-arginine translocation (Tat) pathway of Corynebacterium glutamicum},
  series = {Microbial biotechnology},
  journal   = {Microbial biotechnology},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  issn      = {1751-7915},
  pages     = {202 -- 206},
  year      = {2013},
  language  = {en}
}
@article{SchiffelsPinkenburgScheldenetal.2013,
  author    = {Schiffels, Johannes and Pinkenburg, Olaf and Schelden, Maximilian and Aboulnaga, El-Hussiny A. A. and Baumann, Marcus and Selmer, Thorsten},
  title     = {An innovative cloning platform enables large-scale production and maturation of an oxygen-tolerant [NiFe]-hydrogenase from cupriavidus necator in Escherichia coli},
  series = {PLOS one. 2013},
  journal   = {PLOS one. 2013},
  publisher = {Public Library of Science},
  address   = {San Francisco, California},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0068812},
  year      = {2013},
  language  = {en}
}
@article{SchiffelsSelmer2015,
  author    = {Schiffels, Johannes and Selmer, Thorsten},
  title     = {A flexible toolbox to study protein-assisted metalloenzyme assembly in vitro},
  series = {Biotechnology and Bioengineering},
  volume    = {112},
  journal   = {Biotechnology and Bioengineering},
  number    = {11},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1097-0290},
  doi       = {10.1002/bit.25658},
  pages     = {2360 -- 2372},
  year      = {2015},
  language  = {en}
}
@article{SchiffelsSelmer2019,
  author    = {Schiffels, Johannes and Selmer, Thorsten},
  title     = {Combinatorial assembly of ferredoxin-linked modules in Escherichia coli yields a testing platform for Rnf-complexes},
  series = {Biotechnology and Bioengineering},
  journal   = {Biotechnology and Bioengineering},
  number    = {accepted article},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/bit.27079},
  pages     = {1 -- 36},
  year      = {2019},
  language  = {en}
}
@article{SchmidtTonnesmannFoersteretal.2000,
  author    = {Schmidt, R. and Tonnesmann, A. and F{\"o}rster, Arnold and Grimm, M. and Kordos, P. and L{\"u}th, H.},
  title     = {Metamorphic InAlAs/InGaAs HEMT's on GaAs substrates using an InP buffer layer},
  series = {8th IEEE International Symposium on High Performance Electron Devices for Microwave and Optoelectronic Applications : EDMO 2000 ; [13 - 14 November 2000, University of Glasgow] / organised by Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow Scotland. MTT/ED/AP/LEO Societies Joint Chapter, United Kingdom and Republic of Ireland Section. With technical co-sponsorship from IEEE Electron Device Society},
  journal   = {8th IEEE International Symposium on High Performance Electron Devices for Microwave and Optoelectronic Applications : EDMO 2000 ; [13 - 14 November 2000, University of Glasgow] / organised by Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow Scotland. MTT/ED/AP/LEO Societies Joint Chapter, United Kingdom and Republic of Ireland Section. With technical co-sponsorship from IEEE Electron Device Society},
  publisher = {IEEE Operations Center},
  address   = {Piscataway, NJ},
  isbn      = {0-7803-6550-X},
  pages     = {95 -- 98},
  year      = {2000},
  language  = {en}
}
@article{SchmittFassbenderLuethetal.2000,
  author    = {Schmitt, G. and Faßbender, F. and L{\"u}th, H. and Sch{\"o}ning, Michael Josef and Schultze, J. W. and Buß, G.},
  title     = {Passivation and corrosion of microelectrode arrays},
  series = {Materials and Corrosion. 51 (2000), H. 1},
  journal   = {Materials and Corrosion. 51 (2000), H. 1},
  isbn      = {0947-5117},
  pages     = {20 -- 25},
  year      = {2000},
  language  = {en}
}
@article{SchmittWernerSchoening2002,
  author    = {Schmitt, G. and Werner, C. and Sch{\"o}ning, Michael Josef},
  title     = {Microelectrochemical efficiency evaluation of inhibitors for CO2 corrosion of carbon steel under high shear stress gradients},
  series = {Corrosion 2002. Conference Proceedings. NACExpo, 57th Annual Conference and Exhibition, Denver, US, Apr 7-11, 2002},
  journal   = {Corrosion 2002. Conference Proceedings. NACExpo, 57th Annual Conference and Exhibition, Denver, US, Apr 7-11, 2002},
  publisher = {NACE International},
  address   = {Houston, Texas},
  pages     = {1 -- 11},
  year      = {2002},
  language  = {en}
}
@article{SchollMoraisGabrieletal.2017,
  author    = {Scholl, Fabio and Morais, Paulo and Gabriel, Rayla and Sch{\"o}ning, Michael Josef and Siqueira, Jose Roberto, Jr. and Caseli, Luciano},
  title     = {Carbon nanotubes arranged as smart interfaces in lipid Langmuir-Blodgett films enhancing the enzymatic properties of penicillinase for biosensing applications},
  series = {Applied Materials \& Interfaces},
  volume    = {9},
  journal   = {Applied Materials \& Interfaces},
  number    = {36},
  publisher = {ACS},
  address   = {Washington},
  issn      = {1944-8252},
  doi       = {10.1021/acsami.7b08095},
  pages     = {31054 -- 31066},
  year      = {2017},
  abstract  = {In this paper, carbon nanotubes (CNTs) were incorporated in penicillinase-phospholipid Langmuir and Langmuir-Blodgett (LB) films to enhance the enzyme catalytic properties. Adsorption of the penicillinase and CNTs at dimyristoylphosphatidic acid (DMPA) monolayers at the air-water interface was investigated by surface pressure-area isotherms, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to solid supports through the LB technique, forming mixed DMPA-CNTs-PEN films, which were investigated by quartz crystal microbalance, vibrational spectroscopy, and atomic force microscopy. Enzyme activity was studied with UV-vis spectroscopy and the feasibility of the supramolecular device nanostructured as ultrathin films were essayed in a capacitive electrolyte-insulator-semiconductor (EIS) sensor device. The presence of CNTs in the enzyme-lipid LB film not only tuned the catalytic activity of penicillinase but also helped conserve its enzyme activity after weeks, showing increased values of activity. Viability as penicillin sensor was demonstrated with capacitance/voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results may be related not only to the nanostructured system provided by the film, but also to the synergism between the compounds on the active layer, leading to a surface morphology that allowed a fast analyte diffusion because of an adequate molecular accommodation, which also preserved the penicillinase activity. This work therefore demonstrates the feasibility of employing LB films composed of lipids, CNTs, and enzymes as EIS devices for biosensing applications.},
  language  = {en}
}
@article{SchroeterHoffmannVoigtetal.2014,
  author    = {Schroeter, Rebecca and Hoffmann, Tamara and Voigt, Birgit and Meyer, Hanna and Bleisteiner, Monika and Muntel, Jan and J{\"u}rgen, Britta and Albrecht, Dirk and Becher, D{\"o}rte and Lalk, Michael and Evers, Stefan and Bongaerts, Johannes and Maurer, Karl-Heinz and Putzer, Harald and Hecker, Michael and Schweder, Thomas and Bremer, Erhard},
  title     = {Stress responses of the industrial workhorse Bacillus licheniformis to osmotic challenges},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {11},
  publisher = {PLOS},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0080956},
  pages     = {e80956},
  year      = {2014},
  abstract  = {The Gram-positive endospore-forming bacterium Bacillus licheniformis can be found widely in nature and it is exploited in industrial processes for the manufacturing of antibiotics, specialty chemicals, and enzymes. Both in its varied natural habitats and in industrial settings, B. licheniformis cells will be exposed to increases in the external osmolarity, conditions that trigger water efflux, impair turgor, cause the cessation of growth, and negatively affect the productivity of cell factories in biotechnological processes. We have taken here both systems-wide and targeted physiological approaches to unravel the core of the osmostress responses of B. licheniformis. Cells were suddenly subjected to an osmotic upshift of considerable magnitude (with 1 M NaCl), and their transcriptional profile was then recorded in a time-resolved fashion on a genome-wide scale. A bioinformatics cluster analysis was used to group the osmotically up-regulated genes into categories that are functionally associated with the synthesis and import of osmostress-relieving compounds (compatible solutes), the SigB-controlled general stress response, and genes whose functional annotation suggests that salt stress triggers secondary oxidative stress responses in B. licheniformis. The data set focusing on the transcriptional profile of B. licheniformis was enriched by proteomics aimed at identifying those proteins that were accumulated by the cells through increased biosynthesis in response to osmotic stress. Furthermore, these global approaches were augmented by a set of experiments that addressed the synthesis of the compatible solutes proline and glycine betaine and assessed the growth-enhancing effects of various osmoprotectants. Combined, our data provide a blueprint of the cellular adjustment processes of B. licheniformis to both sudden and sustained osmotic stress.},
  language  = {en}
}
@article{SchrothLuethHummeletal.2001,
  author    = {Schroth, P. and L{\"u}th, H. and Hummel, Hans E. and Sch{\"u}tz, S. and Sch{\"o}ning, Michael Josef},
  title     = {Characterising an insect antenna as a receptor for a biosensor by means of impedance spectroscopy},
  series = {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},
  journal   = {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},
  publisher = {Elsevier [u.a.]},
  address   = {Amsterdam [u.a.]},
  isbn      = {0-08-044014-2},
  pages     = {293 -- 297},
  year      = {2001},
  language  = {en}
}
@article{SchrothSchoeningLuethetal.2001,
  author    = {Schroth, P. and Sch{\"o}ning, Michael Josef and L{\"u}th, H. and Weißbecker, B. and Hummel, Hans E. and Sch{\"u}tz, S.},
  title     = {Extending the capabilities of an antenna/chip biosensor by employing various insect species},
  series = {Sensors and Actuators B. 78 (2001), H. 1-3},
  journal   = {Sensors and Actuators B. 78 (2001), H. 1-3},
  isbn      = {0925-4005},
  pages     = {1 -- 5},
  year      = {2001},
  language  = {en}
}
@article{SchrothSchoeningLuethetal.2000,
  author    = {Schroth, P. and Sch{\"o}ning, Michael Josef and L{\"u}th, H. and Weißbecker, B. and Hummel, Hans E. and Sch{\"u}tz, S.},
  title     = {Extending the capabilities of an antenna/chip biosensor by employing various insect species},
  series = {Proceedings : Copenhagen, Denmark, 27 - 30 August 2000 / [ed.: R. de Reus ...]},
  journal   = {Proceedings : Copenhagen, Denmark, 27 - 30 August 2000 / [ed.: R. de Reus ...]},
  publisher = {MIC, Mikroelektronik Centret},
  address   = {Lyngby, Denmark},
  isbn      = {87-89935-50-0},
  pages     = {27 -- 30},
  year      = {2000},
  language  = {en}
}
@article{SchrothSchoeningSchuetzetal.2000,
  author    = {Schroth, P. and Sch{\"o}ning, Michael Josef and Sch{\"u}tz, S. and Steffen, A. and Weißbecker, B. and Hummel, Hans E. and Kordos, P. and L{\"u}th, H.},
  title     = {Nachweis von organischen Duftstoffen durch Biosensoren auf der Basis von Insektenantennen},
  series = {Gesellschaft Mess- und Automatisierungstechnik: Sensoren und Meßsysteme 2000 : Tagung Ludwigsburg, 13. und 14. M{\"a}rz 2000 / VDI/VDE-Gesellschaft Meß- und Automatisierungstechnik},
  journal   = {Gesellschaft Mess- und Automatisierungstechnik: Sensoren und Meßsysteme 2000 : Tagung Ludwigsburg, 13. und 14. M{\"a}rz 2000 / VDI/VDE-Gesellschaft Meß- und Automatisierungstechnik},
  publisher = {VDI-Verl.},
  address   = {D{\"u}sseldorf:},
  isbn      = {3-18-091530-7},
  pages     = {107 -- 114},
  year      = {2000},
  language  = {de}
}
@article{SchrothWeissbeckerSchuetzetal.2002,
  author    = {Schroth, P. and Weißbecker, B. and Sch{\"u}tz, S. and Ecken, H. and Yoshinobu, T. and L{\"u}th, H. and Sch{\"o}ning, Michael Josef},
  title     = {Bioelectronic signal processing - intact chemoreceptors coupled to field-effect devices},
  series = {Lecture Notes of the ICB Seminars},
  journal   = {Lecture Notes of the ICB Seminars},
  publisher = {MCB},
  address   = {Warsaw},
  pages     = {28 -- 42},
  year      = {2002},
  language  = {en}
}
@article{SchrothWeissbeckerSchuetzetal.2001,
  author    = {Schroth, P. and Weißbecker, B. and Sch{\"u}tz, S. and Ecken, H. and Yoshinobu, T. and L{\"u}th, H. and Sch{\"o}ning, Michael Josef},
  title     = {Bioelectronic signal processing - intact chemoreceptors coupled to field-effect devices},
  series = {Biocybernetics and Biomedical Engineering. 21 (2001), H. 3},
  journal   = {Biocybernetics and Biomedical Engineering. 21 (2001), H. 3},
  isbn      = {0208-5216},
  pages     = {27 -- 42},
  year      = {2001},
  language  = {en}
}
@article{SchubertSchoeningMourzinaetal.2001,
  author    = {Schubert, J. and Sch{\"o}ning, Michael Josef and Mourzina, Y. G. and Legin, A. V. and Vlasov, Y. G. and Zander, W. and L{\"u}th, H.},
  title     = {Multicomponent thin films for electrochemical sensor applications prepared by pulsed laser deposition},
  series = {Sensors and Actuators B. 76 (2001), H. 1-3},
  journal   = {Sensors and Actuators B. 76 (2001), H. 1-3},
  isbn      = {0925-4005},
  pages     = {327 -- 330},
  year      = {2001},
  language  = {en}
}
@inproceedings{SchubertSchoening2010,
  author    = {Schubert, Nicole and Sch{\"o}ning, Michael Josef},
  title     = {3. Graduiertentagung der FH Aachen},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:a96-opus-3386},
  year      = {2010},
  abstract  = {Doktoranden der FH Aachen stellen ihre wissenschaftlichen Arbeiten aus verschiedenen Fachdisziplinen vor.},
  subject      = {Graduiertentagung},
  language  = {mul}
}
@phdthesis{Schusser2015,
  author    = {Schusser, Sebastian},
  title     = {Sensor-based degradation monitoring for the evaluation of (bio)degradable polymers},
  publisher = {Universiteit Hasselt ; FH Aachen},
  address   = {Hasselt ; Aachen},
  pages     = {145 Seiten},
  year      = {2015},
  language  = {en}
}
@inproceedings{SchusserBaeckerLeinhosetal.2013,
  author    = {Schusser, Sebastian and B{\"a}cker, Matthias and Leinhos, Marcel and Krischer, M. and Wenzel, L. and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Sensorkonzept zur in vitro Echtzeitmessung des Degradationsverhaltens von biodegradierbaren Biopolymeren},
  series = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  booktitle = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  organization    = {Dresdner Sensor-Symposium <11, 2013>},
  isbn      = {978-3-9813484-5-3},
  pages     = {174 -- 177},
  year      = {2013},
  language  = {de}
}
@article{SchusserKrischerMolinetal.2015,
  author    = {Schusser, Sebastian and Krischer, M. and Molin, D. G. M. and Akker, N. M. S. van den and B{\"a}cker, Matthias and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {Sensor System for in-situ and Real-time Monitoring of Polymer (bio) degradation},
  series = {Procedia Engineering},
  volume    = {120},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2015.08.815},
  pages     = {948 -- 951},
  year      = {2015},
  abstract  = {A sensor system for investigating (bio)degradationprocesses of polymers is presented. The system utilizes semiconductor field-effect sensors and is capable of monitoring the degradation process in-situ and in real-time. The degradation of the polymer poly(d,l-lactic acid) is exemplarily monitored in solutions with different pH value, pH-buffer solution containing the model enzyme lipase from Rhizomucormiehei and cell-culture medium containing supernatants from stimulated and non-stimulated THP-1-derived macrophages mimicking activation of the immune system.},
  language  = {en}
}
@article{SchusserKrischerBaeckeretal.2015,
  author    = {Schusser, Sebastian and Krischer, Maximillian and B{\"a}cker, Matthias and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Monitoring of the Enzymatically Catalyzed Degradation of Biodegradable Polymers by Means of Capacitive Field-Effect Sensors},
  series = {Analytical Chemistry},
  volume    = {87},
  journal   = {Analytical Chemistry},
  number    = {13},
  publisher = {ACS Publications},
  address   = {Washington, DC},
  issn      = {1520-6882},
  doi       = {10.1021/acs.analchem.5b00617},
  pages     = {6607 -- 6613},
  year      = {2015},
  abstract  = {Designing novel or optimizing existing biodegradable polymers for biomedical applications requires numerous tests on the effect of substances on the degradation process. In the present work, polymer-modified electrolyte-insulator-semiconductor (PMEIS) sensors have been applied for monitoring an enzymatically catalyzed degradation of polymers for the first time. The thin films of biodegradable polymer poly(d,l-lactic acid) and enzyme lipase were used as a model system. During degradation, the sensors were read-out by means of impedance spectroscopy. In order to interpret the data obtained from impedance measurements, an electrical equivalent circuit model was developed. In addition, morphological investigations of the polymer surface have been performed by means of in situ atomic force microscopy. The sensor signal change, which reflects the progress of degradation, indicates an accelerated degradation in the presence of the enzyme compared to hydrolysis in neutral pH buffer media. The degradation rate increases with increasing enzyme concentration. The obtained results demonstrate the potential of PMEIS sensors as a very promising tool for in situ and real-time monitoring of degradation of polymers.},
  language  = {en}
}
@article{SchusserLeinhosBaeckeretal.2013,
  author    = {Schusser, Sebastian and Leinhos, Marcel and B{\"a}cker, Matthias and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Impedance spectroscopy: A tool for real-time in situ monitoring of the degradation of biopolymers},
  series = {Physica Status Solidi (A)},
  volume    = {210},
  journal   = {Physica Status Solidi (A)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1521-396X ; 0031-8965},
  doi       = {10.1002/pssa.201200941},
  pages     = {905 -- 910},
  year      = {2013},
  abstract  = {Investigation of the degradation kinetics of biodegradable polymers is essential for the development of implantable biomedical devices with predicted biodegradability. In this work, an impedimetric sensor has been applied for real-time and in situ monitoring of degradation processes of biopolymers. The sensor consists of two platinum thin-film electrodes covered by a polymer film to be studied. The benchmark biomedical polymer poly(D,L-lactic acid) (PDLLA) was used as a model system. PDLLA films were deposited on the sensor structure from a polymer solution by using the spin-coating method. The degradation kinetics of PDLLA films have been studied in alkaline solutions of pH 9 and 12 by means of an impedance spectroscopy (IS) method. Any changes in a polymer capacitance/resistance induced by water uptake and/or polymer degradation will modulate the global impedance of the polymer-covered sensor that can be used as an indicator of the polymer degradation. The degradation rate can be evaluated from the time-dependent impedance spectra. As expected, a faster degradation has been observed for PDLLA films exposed to pH 12 solution.},
  language  = {en}
}
@article{SchusserMenzelBaeckeretal.2013,
  author    = {Schusser, Sebastian and Menzel, S. and B{\"a}cker, Matthias and Leinhos, Marcel and Poghossian, Arshak and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Degradation of thin poly(lactic acid) films: characterization by capacitance-voltage, atomic force microscopy, scanning electron microscopy and contact-angle measurements},
  series = {Electrochimica Acta},
  volume    = {Vol. 113},
  journal   = {Electrochimica Acta},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3859 (E-Journal); 0013-4686 (Print)},
  pages     = {779 -- 784},
  year      = {2013},
  language  = {en}
}
@article{SchusserPoghossianBaeckeretal.2015,
  author    = {Schusser, Sebastian and Poghossian, Arshak and B{\"a}cker, Matthias and Krischer, M. and Leinhos, Marcel and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {An application of field-effect sensors for in-situ monitoring of degradation of biopolymers},
  series = {Sensors and actuators B: Chemical},
  volume    = {207, Part B},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2014.10.058},
  pages     = {954 -- 959},
  year      = {2015},
  abstract  = {The characterization of the degradation kinetics of biodegradable polymers is mandatory with regard to their proper application. In the present work, polymer-modified electrolyte-insulator-semiconductor (PMEIS) field-effect sensors have been applied for in-situ monitoring of the pH-dependent degradation kinetics of the commercially available biopolymer poly(d,l-lactic acid) (PDLLA) in buffer solutions from pH 3 to pH 13. PDLLA films of 500 nm thickness were deposited on the surface of an Al-p-Si-SiO2-Ta2O5 structure from a polymer solution by means of spin-coating method. The PMEIS sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by degradation processes. A faster degradation has been observed for PDLLA films exposed to alkaline solutions (pH 9, pH 11 and pH 13).},
  language  = {en}
}
@article{SchusserPoghossianBaeckeretal.2012,
  author    = {Schusser, Sebastian and Poghossian, Arshak and B{\"a}cker, Matthias and Leinhos, Marcel and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Characterization of biodegradable polymers with capacitive field-effect sensors},
  series = {Sensors and actuators B: Chemical},
  volume    = {187},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2012.07.099},
  pages     = {2 -- 7},
  year      = {2012},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{SchusserVaessenSchoening2011,
  author    = {Schusser, Sebastian and Vaeßen, Christiane and Sch{\"o}ning, Michael Josef},
  title     = {4. Graduiertentagung der FH Aachen 24. November 2011},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:a96-opus-3530},
  year      = {2011},
  abstract  = {Tagungsband der 4. Graduiertentagung der FH Aachen am 24. November 2011 Proceedings from the 4th Graduate Symposium, FH Aachen, Germany, November 24th, 2011 Aachen, November 2011. 62 Seiten},
  subject      = {Graduiertentagung},
  language  = {de}
}
@inproceedings{SchusserVaessenSchoening2012,
  author    = {Schusser, Sebastian and Vaeßen, Christiane and Sch{\"o}ning, Michael Josef},
  title     = {5. Graduiertentagung der FH Aachen 15. November 2012},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:a96-opus-50425},
  pages     = {52},
  year      = {2012},
  abstract  = {Tagungsband der 5. Graduiertentagung der FH Aachen am 15. November 2012},
  language  = {de}
}