TY - JOUR A1 - Delle, Lotta E. A1 - Huck, Christina A1 - Bäcker, Matthias A1 - Müller, Frank A1 - Grandthyll, Samuel A1 - Jacobs, Karin A1 - Lilischkis, Rainer A1 - Vu, Xuan T. A1 - Schöning, Michael Josef A1 - Wagner, Patrick A1 - Thoelen, Roland A1 - Weil, Maryam A1 - Ingebrandt, Sven T1 - Impedimetric immunosensor for the detection of histamine based on reduced graphene oxide JF - Physica status solidi (a) Y1 - 2015 U6 - http://dx.doi.org/10.1002/pssa.201431863 SN - 1862-6319 VL - 212 IS - 6 SP - 1327 EP - 1334 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Henken, F. E. A1 - Oosterhuis, K. A1 - Öhlschläger, Peter A1 - Bosch, L. A1 - Hooijberg, E. A1 - Haanen, J. B. A. G. A1 - Steenbergen, R. D. M. T1 - Preclinical safety evaluation of DNA vaccines encoding modified HPV16 E6 and E7 JF - Vaccine N2 - Persistent infection with high-risk human papillomaviruses (hrHPV) can result in the formation of anogenital cancers. As hrHPV proteins E6 and E7 are required for cancer initiation and maintenance, they are ideal targets for immunotherapeutic interventions. Previously, we have described the development of DNA vaccines for the induction of HPV16 E6 and E7 specific T cell immunity. These vaccines consist of ‘gene-shuffled’ (SH) versions of HPV16 E6 and E7 that were fused to Tetanus Toxin Fragment C domain 1 (TTFC) and were named TTFC-E6SH and TTFC-E7SH. Gene-shuffling was performed to avoid the risk of inducing malignant transformation at the vaccination site. Here, we describe the preclinical safety evaluation of these candidate vaccines by analysis of their transforming capacity in vitro using established murine fibroblasts (NIH 3T3 cells) and primary human foreskin keratinocytes (HFKs). We demonstrate that neither ectopic expression of TTFC-E6SH and TTFC-E7SH alone or in combination enabled NIH 3T3 cells to form colonies in soft agar. In contrast, expression of HPV16 E6WT and E7WT alone or in combination resulted in effective transformation. Similarly, retroviral transduction of HFKs from three independent donors with both TTFC-E6SH and TTFC-E7SH alone or in combination did not show any signs of immortalization. In contrast, the combined expression of E6WT and E7WT induced immortalization in HFKs from all donors. Based on these results we consider it justified to proceed to clinical evaluation of DNA vaccines encoding TTFC-E6SH and TTFC-E7SH in patients with HPV16 associated (pre)malignancies. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.vaccine.2012.04.013 SN - 0264-410X VL - 30 IS - 28 SP - 4259 EP - 4266 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Immel, Timo A1 - Grützke, Martin A1 - Späte, Anne-Katrin A1 - Groth, Ulrich A1 - Öhlschläger, Peter A1 - Huhn, Thomas T1 - Synthesis and X-ray structure analysis of a heptacoordinate titanium(IV)-bis-chelate with enhanced in vivo antitumor efficacy JF - Chemical Communications N2 - Chelate stabilization of a titanium(IV)–salan alkoxide by ligand exchange with 2,6-pyridinedicarboxylic acid (dipic) resulted in heptacoordinate complex 3 which is not redox-active, stable on silica gel and has increased aqueous stability. 3 is highly toxic in HeLa S3 and Hep G2 and has enhanced antitumor efficacy in a mouse cervical-cancer model. Y1 - 2012 U6 - http://dx.doi.org/10.1039/C2CC31624B SN - 1364-548X VL - 48 IS - 46 SP - 5790 EP - 5792 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Bronder, Thomas A1 - Poghossian, Arshak A1 - Scheja, Sabrina A1 - Wu, Chunsheng A1 - Keusgen, Michael A1 - Mewes, Dieter A1 - Schöning, Michael Josef T1 - DNA Immobilization and Hybridization Detection by the Intrinsic Molecular Charge Using Capacitive Field-Effect Sensors Modified with a Charged Weak Polyelectrolyte Layer JF - Applied Materials & Interfaces N2 - Miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge favor the semiconductor field-effect platform as one of the most attractive approaches for the development of label-free DNA chips. In this work, a capacitive field-effect EIS (electrolyte–insulator–semiconductor) sensor covered with a layer-by-layer prepared, positively charged weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was used for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization. The negatively charged probe single-stranded DNA (ssDNA) molecules were electrostatically adsorbed onto the positively charged PAH layer, resulting in a preferentially flat orientation of the ssDNA molecules within the Debye length, thus yielding a reduced charge-screening effect and a higher sensor signal. Each sensor-surface modification step (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), reducing an unspecific adsorption by a blocking agent, incubation with noncomplementary DNA (ncDNA) solution) was monitored by means of capacitance–voltage and constant-capacitance measurements. In addition, the surface morphology of the PAH layer was studied by atomic force microscopy and contact-angle measurements. High hybridization signals of 34 and 43 mV were recorded in low-ionic strength solutions of 10 and 1 mM, respectively. In contrast, a small signal of 4 mV was recorded in the case of unspecific adsorption of fully mismatched ncDNA. The density of probe ssDNA and dsDNA molecules as well as the hybridization efficiency was estimated using the experimentally measured DNA immobilization and hybridization signals and a simplified double-layer capacitor model. The results of field-effect experiments were supported by fluorescence measurements, verifying the DNA-immobilization and hybridization event. Y1 - 2015 U6 - http://dx.doi.org/10.1021/acsami.5b05146 VL - 36 IS - 7 SP - 20068 EP - 20075 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Oberländer, Jan A1 - Jildeh, Zaid B. A1 - Kirchner, Patrick A1 - Wendeler, Luisa A1 - Bromm, Alexander A1 - Iken, Heiko A1 - Wagner, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Study of Interdigitated Electrode Arrays Using Experiments and Finite Element Models for the Evaluation of Sterilization Processes JF - Sensors N2 - In this work, a sensor to evaluate sterilization processes with hydrogen peroxide vapor has been characterized. Experimental, analytical and numerical methods were applied to evaluate and study the sensor behavior. The sensor set-up is based on planar interdigitated electrodes. The interdigitated electrode structure consists of 614 electrode fingers spanning over a total sensing area of 20 mm2. Sensor measurements were conducted with and without microbiological spores as well as after an industrial sterilization protocol. The measurements were verified using an analytical expression based on a first-order elliptical integral. A model based on the finite element method with periodic boundary conditions in two dimensions was developed and utilized to validate the experimental findings. Y1 - 2015 U6 - http://dx.doi.org/10.3390/s151026115 SN - 1424-8220 N1 - This article belongs to the Special Issue "Gas Sensors—Designs and Applications" VL - 15 IS - 10 SP - 26115 EP - 26127 PB - MDPI CY - Basel ER - TY - CHAP A1 - Oberländer, Jan A1 - Jildeh, Zaid B. A1 - Kirchner, Patrick A1 - Wendeler, Luisa A1 - Bromm, Alexander A1 - Iken, Heiko A1 - Wagner, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Experimental and numerical evaluation of interdigitated electrode array for monitoring gaseous sterilization processes T2 - 12. Dresdner Sensor-Symposium 2015 Y1 - 2015 U6 - http://dx.doi.org/10.5162/12dss2015/P3.11 SP - 163 EP - 168 ER - TY - JOUR A1 - Schusser, Sebastian A1 - Krischer, Maximillian A1 - Bäcker, Matthias A1 - Poghossian, Arshak A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Monitoring of the Enzymatically Catalyzed Degradation of Biodegradable Polymers by Means of Capacitive Field-Effect Sensors JF - Analytical Chemistry N2 - 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. Y1 - 2015 U6 - http://dx.doi.org/10.1021/acs.analchem.5b00617 SN - 1520-6882 VL - 87 IS - 13 SP - 6607 EP - 6613 PB - ACS Publications CY - Washington, DC ER - TY - JOUR A1 - Miyamato, Ko-ichiro A1 - Sakakita, Sakura A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Application of chemical imaging sensor to in-situ pH imaging in the vicinity of a corroding metal surface JF - Electrochimica Acta N2 - The chemical imaging sensor was applied to in-situ pH imaging of the solution in the vicinity of a corroding surface of stainless steel under potentiostatic polarization. A test piece of polished stainless steel was placed on the sensing surface leaving a narrow gap filled with artificial seawater and the stainless steel was corroded under polarization. The pH images obtained during polarization showed correspondence between the region of lower pH and the site of corrosion. It was also found that the pH value in the gap became as low as 2 by polarization, which triggered corrosion. Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.electacta.2015.07.184 SN - 0013-4686 VL - 183 SP - 137 EP - 142 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Oberländer, Jan A1 - Kirchner, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Strategies in developing thin-film sensors for monitoring aseptic food processes : Theoretical considerations and investigations of passivation materials JF - Electrochimica Acta N2 - The sterilization of packages in aseptic food processes is highly significant to maintain a consumer-safe product with extended shelf-life. Today, the sterilization of food packages is predominantly accomplished by gaseous hydrogen peroxide (H2O2) in combination with heat. In order to monitor this sterilization process, calorimetric gas sensors as differential set-up of two platinum temperature sensors representing a catalytically active (additionally deposition of MnO2) and a passive segment have been recently developed. The temperature rise of the exothermic decomposition serves as an indicator of the present H2O2 concentration. In the present work, a theoretical approach considering the sensor’s thermochemistry and physical transport phenomena was formulated to evaluate the temperature rise based on the energy content of gaseous H2O2. In a further part of this work, three polymers have been analyzed with respect to their application as passivation materials. The examined polymers are photoresist SU-8, perfluoroalkoxy (PFA) and fluorinated ethylene propylene (FEP). Thermal analyses by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) have been conducted to determine the operation limits of the polymers. The overall chemical resistance and stability of the polymers against the harsh environmental conditions during the sterilization process have been examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.electacta.2015.06.126 SN - 0013-4686 VL - 183 SP - 130 EP - 136 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Poghossian, Arshak A1 - Schusser, Sebastian A1 - Bäcker, M. A1 - Leinhos, Marcel A1 - Schöning, Michael Josef T1 - Real-time in-situ electrical monitoring of the degradation of biopolymers using semiconductor field-effect devices T2 - Biodegradable biopolymers. Vol. 1 Y1 - 2015 SN - 978-1-63483-632-6 SP - 135 EP - 153 PB - Nova Science Publ. CY - Hauppauge ER -