TY - JOUR A1 - Wu, Chunsheng A1 - Bronder, Thomas A1 - Poghossian, Arshak A1 - Werner, Frederik A1 - Bäcker, Matthias A1 - Schöning, Michael Josef T1 - Label-free electrical detection of DNA with a multi-spot LAPS: First step towards light-addressable DNA chips JF - Physica status solidi A : Applications and materials science N2 - A multi-spot (4 × 4 spots) light-addressable potentiometric sensor (MLAPS) consisting of an Al–p-Si–SiO2 structure has been applied for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge for the first time. Single-stranded probe ssDNA molecules (20 bases) were covalently immobilized onto the silanized SiO2 gate surface. The unspecific adsorption of mismatch ssDNA on the MLAPS gate surface was blocked by bovine serum albumin molecules. To reduce the screening effect and to achieve a high sensor signal, the measurements were performed in a low ionic-strength solution. The photocurrent–voltage (I–V) curves were simultaneously recorded on all 16 spots after each surface functionalization step. Large shifts of I–V curves of 25 mV were registered after the DNA immobilization and hybridization event. In contrast, a small potential shift (∼5 mV) was observed in case of mismatch ssDNA, revealing good specificity of the sensor. The obtained results demonstrate the potential of the MLAPS as promising transducer platform for the multi-spot label-free electrical detection of DNA molecules by their intrinsic molecular charge. Y1 - 2014 U6 - http://dx.doi.org/10.1002/pssa.201330442 SN - 1521-396X (E-Journal); 1862-6319 (E-Journal); 0031-8965 (Print); 1862-6300 (Print) VL - 211 IS - 6 SP - 1423 EP - 1428 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Whitehead, Mark A1 - Öhlschläger, Peter A1 - Almajhdi, Fahad N. A1 - Alloza, Leonor A1 - Marzábal, Pablo A1 - Meyers, Ann E. A1 - Hitzeroth, Inga I. A1 - Rybicki, Edward P. T1 - Human papillomavirus (HPV) type 16 E7 protein bodies cause tumour regression in mice JF - BMC cancer Y1 - 2014 U6 - http://dx.doi.org/10.1186/1471-2407-14-367 SN - 1471-2407 IS - 14:367 SP - 1 EP - 15 PB - BioMed Central CY - London ER - TY - JOUR A1 - Wagner, Patrick A1 - Doll, Theodor A1 - Schöning, Michael Josef T1 - Engineering of functional interfaces / Patrick Wagner ; Theodor Doll ; Michael J. Schöning (eds.) JF - Physica status solidi (A) : Applications and materials science Y1 - 2014 U6 - http://dx.doi.org/10.1002/pssa.201470241 SN - 1521-396X (E-Book); 1862-6319 (E-Book); 0031-8965 (Print); 1862-6300 (Print) VL - 211 IS - 6 SP - 1339 EP - 1339 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Takenaga, Shoko A1 - Biselli, Manfred A1 - Schnitzler, Thomas A1 - Öhlschläger, Peter A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Toward multi-analyte bioarray sensors: LAPS-based on-chip determination of a Michaelis–Menten-like kinetics for cell culturing JF - Physica status solidi A : Applications and materials science N2 - The metabolic activity of Chinese hamster ovary (CHO) cells was observed using a light-addressable potentiometric sensor (LAPS). The dependency toward different glucose concentrations (17–200 mM) follows a Michaelis–Menten kinetics trajectory with Kₘ = 32.8 mM, and the obtained Kₘ value in this experiment was compared with that found in literature. In addition, the pH shift induced by glucose metabolism of tumor cells transfected with the HPV-16 genome (C3 cells) was successfully observed. These results indicate the possibility to determine the tumor cells metabolism with a LAPS-based measurement device. Y1 - 2014 U6 - http://dx.doi.org/10.1002/pssa.201330464 SN - 1521-396X (E); 1862-6319 (E-Journal); 0031-8965 (Print); 1862-6300 (Print) VL - 211 IS - 6 SP - 1410 EP - 1415 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Siqueira, Jose R. A1 - Molinnus, Denise A1 - Beging, Stefan A1 - Schöning, Michael Josef T1 - Incorporating a hybrid urease-carbon nanotubes sensitive nanofilm on capacitive field-effect sensors for urea detection JF - Analytical chemistry N2 - The ideal combination among biomolecules and nanomaterials is the key for reaching biosensing units with high sensitivity. The challenge, however, is to find out a stable and sensitive film architecture that can be incorporated on the sensor’s surface. In this paper, we report on the benefits of incorporating a layer-by-layer (LbL) nanofilm of polyamidoamine (PAMAM) dendrimer and carbon nanotubes (CNTs) on capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors for detecting urea. Three sensor arrangements were studied in order to investigate the adequate film architecture, involving the LbL film with the enzyme urease: (i) urease immobilized directly onto a bare EIS [EIS-urease] sensor; (ii) urease atop the LbL film over the EIS [EIS-(PAMAM/CNT)-urease] sensor; and (iii) urease sandwiched between the LbL film and another CNT layer [EIS-(PAMAM/CNT)-urease-CNT]. The surface morphology of all three urea-based EIS biosensors was investigated by atomic force microscopy (AFM), while the biosensing abilities were studied by means of capacitance–voltage (C/V) and dynamic constant-capacitance (ConCap) measureaments at urea concentrations ranging from 0.1 mM to 100 mM. The EIS-urease and EIS-(PAMAM/CNT)-urease sensors showed similar sensitivity (∼18 mV/decade) and a nonregular signal behavior as the urea concentration increased. On the other hand, the EIS-(PAMAM/CNT)-urease-CNT sensor exhibited a superior output signal performance and higher sensitivity of about 33 mV/decade. The presence of the additional CNT layer was decisive to achieve a urea based EIS sensor with enhanced properties. Such sensitive architecture demonstrates that the incorporation of an adequate hybrid enzyme-nanofilm as sensing unit opens new prospects for biosensing applications using the field-effect sensor platform. Y1 - 2014 U6 - http://dx.doi.org/10.1021/ac500458s SN - 1520-6882 (E-Journal); 0003-2700 (Print); 0096-4484 (Print) VL - 86 IS - 11 SP - 5370 EP - 5375 PB - ACS Publications CY - Columbus ER - TY - JOUR A1 - Schroeter, Rebecca A1 - Hoffmann, Tamara A1 - Voigt, Birgit A1 - Meyer, Hanna A1 - Bleisteiner, Monika A1 - Muntel, Jan A1 - Jürgen, Britta A1 - Albrecht, Dirk A1 - Becher, Dörte A1 - Lalk, Michael A1 - Evers, Stefan A1 - Bongaerts, Johannes A1 - Maurer, Karl-Heinz A1 - Putzer, Harald A1 - Hecker, Michael A1 - Schweder, Thomas A1 - Bremer, Erhard T1 - Stress responses of the industrial workhorse Bacillus licheniformis to osmotic challenges JF - PLoS ONE N2 - 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. Y1 - 2014 U6 - http://dx.doi.org/10.1371/journal.pone.0080956 SN - 1932-6203 VL - 8 IS - 11 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Label-free sensing of biomolecules with field-effect devices for clinical applications JF - Electroanalysis N2 - Among the variety of transducer concepts proposed for label-free detection of biomolecules, the semiconductor field-effect device (FED) is one of the most attractive platforms. As medical techniques continue to progress towards diagnostic and therapies based on biomarkers, the ability of FEDs for a label-free, fast and real-time detection of multiple pathogenic and physiologically relevant molecules with high specificity and sensitivity offers very promising prospects for their application in point-of-care and personalized medicine for an early diagnosis and treatment of diseases. The presented paper reviews recent advances and current trends in research and development of different FEDs for label-free, direct electrical detection of charged biomolecules by their intrinsic molecular charge. The authors are mainly focusing on the detection of the DNA hybridization event, antibody-antigen affinity reaction as well as clinically relevant biomolecules such as cardiac and cancer biomarkers. Y1 - 2014 U6 - http://dx.doi.org/10.1002/elan.201400073 SN - 1521-4109 (E-Journal); 1040-0397 (Print) VL - 26 IS - 6 SP - 1197 EP - 1213 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Oberländer, Jan A1 - Kirchner, Patrick A1 - Boyen, Hans-Gerd A1 - Schöning, Michael Josef T1 - Detection of hydrogen peroxide vapor by use of manganese(IV) oxide as catalyst for calorimetric gas sensors JF - Physica status solidi A: Applications and materials science N2 - In this work, the catalyst manganese(IV) oxide (MnO2), of calorimetric gas sensors (to monitor the sterilization agent vaporized hydrogen peroxide) has been investigated in more detail. Chemical analyses by means of X-ray-induced photoelectron spectroscopy have been performed to unravel the surface chemistry prior and after exposure to hydrogen peroxide vapor at elevated temperature, as applied in the sterilization processes of beverage cartons. The surface characterization reveals a change in oxidation states of the metal oxide catalyst after exposure to hydrogen peroxide. Additionally, a cleaning effect of the catalyst, which itself is attached to the sensor surface by means of a polymer interlayer, could be observed. Y1 - 2014 U6 - http://dx.doi.org/10.1002/pssa.201330359 SN - 1521-396X (E-Journal); 1862-6319 (E-Journal); 0031-8965 (Print); 1862-6300 (Print) VL - 211 IS - 6 SP - 1372 EP - 1376 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Moseley, Fiona A1 - Halamek, Jan A1 - Kramer, Friederike A1 - Poghossian, Arshak A1 - Schöning, Michael Josef A1 - Katz, Evgeny T1 - An enzyme-based reversible CNOT logic gate realized in a flow system JF - Analyst N2 - An enzyme system organized in a flow device was used to mimic a reversible Controlled NOT (CNOT) gate with two input and two output signals. Reversible conversion of NAD⁺ and NADH cofactors was used to perform a XOR logic operation, while biocatalytic hydrolysis of p-nitrophenyl phosphate resulted in an Identity operation working in parallel. The first biomolecular realization of a CNOT gate is promising for integration into complex biomolecular networks and future biosensor/biomedical applications. Y1 - 2014 U6 - http://dx.doi.org/10.1039/C4AN00133H SN - 1364-5528 (E-Journal) ; 0003-2654 (Print) VL - 139 IS - 8 SP - 1839 EP - 1842 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Itabashi, Akinori A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - High-speed chemical imaging inside a microfluidic channel JF - Sensors and actuators. B: Chemical N2 - In this study, a high-speed chemical imaging system was developed for visualization of the interior of a microfluidic channel. A microfluidic channel was constructed on the sensor surface of the light-addressable potentiometric sensor (LAPS), on which the ion concentrations could be measured in parallel at up to 64 points illuminated by optical fibers. The temporal change of pH distribution inside the microfluidic channel was recorded at a maximum rate of 100 frames per second (fps). The high frame rate allowed visualization of moving interfaces and plugs in the channel even at a flow velocity of 111 mm/s, which suggests the feasibility of plug-based microfluidic devices for flow-injection analysis (FIA). Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.snb.2013.12.090 SN - 1873-3077 (E-Journal); 0925-4005 (Print) VL - 194 SP - 521 EP - 527 PB - Elsevier CY - Amsterdam ER -