@article{SchoeningBronderWuetal.2017, author = {Sch{\"o}ning, Michael Josef and Bronder, Thomas and Wu, Chunsheng and Scheja, Sabrina and Jessing, Max and Metzger-Boddien, Christoph and Keusgen, Michael and Poghossian, Arshak}, title = {Label-Free DNA Detection with Capacitive Field-Effect Devices—Challenges and Opportunities}, series = {Proceedings}, volume = {1}, journal = {Proceedings}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {2504-3900}, doi = {10.3390/proceedings1080719}, pages = {Artikel 719}, year = {2017}, abstract = {Field-effect EIS (electrolyte-insulator-semiconductor) sensors modified with a positively charged weak polyelectrolyte layer have been applied for the electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge. The EIS sensors are able to detect the existence of target DNA amplicons in PCR (polymerase chain reaction) samples and thus, can be used as tool for a quick verification of DNA amplification and the successful PCR process. Due to their miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge, those sensors can serve as possible platform for the development of label-free DNA chips. Possible application fields as well as challenges and limitations will be discussed.}, language = {en} } @article{BaeckerRakowskiKrappenetal.2017, author = {B{\"a}cker, M. and Rakowski, D. and Krappen, E. and Sch{\"o}ning, Michael Josef}, title = {Reinigungsprozesse in der Lebensmittelindustrie. Entwicklung eines Demonstrators zur {\"U}berwachung}, series = {GIT Labor-Fachzeitschrift}, volume = {61}, journal = {GIT Labor-Fachzeitschrift}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0016-3538}, pages = {26 -- 28}, year = {2017}, language = {de} } @article{BreuerMangSchoeningetal.2017, author = {Breuer, Lars and Mang, Thomas and Sch{\"o}ning, Michael Josef and Thoelen, Ronald and Wagner, Torsten}, title = {Investigation of the spatial resolution of a laser-based stimulation process for light-addressable hydrogels with incorporated graphene oxide by means of IR thermography}, series = {Sensors and Actuators A: Physical}, volume = {268}, journal = {Sensors and Actuators A: Physical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0924-4247}, doi = {10.1016/j.sna.2017.11.031}, pages = {126 -- 132}, year = {2017}, language = {en} } @inproceedings{BreuerGuthmannSchoeningetal.2017, author = {Breuer, Lars and Guthmann, Eric and Sch{\"o}ning, Michael Josef and Thoelen, Ronald and Wagner, Torsten}, title = {Light-Stimulated Hydrogels with Incorporated Graphene Oxide as Actuator Material for Flow Control in Microfluidic Applications}, series = {Proceedings Eurosensors 2017 Conference, Paris, France, 3-6 September 2017}, booktitle = {Proceedings Eurosensors 2017 Conference, Paris, France, 3-6 September 2017}, doi = {10.3390/proceedings1040524}, pages = {1 -- 4}, year = {2017}, language = {en} } @article{PilasYaziciSelmeretal.2017, author = {Pilas, Johanna and Yazici, Yasemen and Selmer, Thorsten and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Optimization of an amperometric biosensor array for simultaneous measurement of ethanol, formate, d- and l-lactate}, series = {Electrochimica Acta}, volume = {251}, journal = {Electrochimica Acta}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0013-4686}, doi = {10.1016/j.electacta.2017.07.119}, pages = {256 -- 262}, year = {2017}, abstract = {The immobilization of NAD+-dependent dehydrogenases, in combination with a diaphorase, enables the facile development of multiparametric sensing devices. In this work, an amperometric biosensor array for simultaneous determination of ethanol, formate, d- and l-lactate is presented. Enzyme immobilization on platinum thin-film electrodes was realized by chemical cross-linking with glutaraldehyde. The optimization of the sensor performance was investigated with regard to enzyme loading, glutaraldehyde concentration, pH, cofactor concentration and temperature. Under optimal working conditions (potassium phosphate buffer with pH 7.5, 2.5 mmol L-1 NAD+, 2.0 mmol L-1 ferricyanide, 25 °C and 0.4\% glutaraldehyde) the linear working range and sensitivity of the four sensor elements was improved. Simultaneous and cross-talk free measurements of four different metabolic parameters were performed successfully. The reliable analytical performance of the biosensor array was demonstrated by application in a clarified sample of inoculum sludge. Thereby, a promising approach for on-site monitoring of fermentation processes is provided.}, 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{HonarvarfardGamellaPoghossianetal.2017, author = {Honarvarfard, Elham and Gamella, Maria and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny}, title = {An enzyme-based reversible Controlled NOT (CNOT) logic gate operating on a semiconductor transducer}, series = {Applied Materials Today}, volume = {9}, journal = {Applied Materials Today}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-9407}, doi = {10.1016/j.apmt.2017.08.003}, pages = {266 -- 270}, year = {2017}, abstract = {An enzyme-based biocatalytic system mimicking operation of a logically reversible Controlled NOT (CNOT) gate has been interfaced with semiconductor electronic transducers. Electrolyte-insulator-semiconductor (EIS) structures have been used to transduce chemical changes produced by the enzyme system to an electronically readable capacitive output signal using field-effect features of the EIS device. Two enzymes, urease and esterase, were immobilized on the insulating interface of EIS structure producing local pH changes performing XOR logic operation controlled by various combinations of the input signals represented by urea and ethyl butyrate. Another EIS transducer was functionalized with esterase only, thus performing Identity (ID) logic operation for the ethyl butyrate input. Both semiconductor devices assembled in parallel operated as a logically reversible CNOT gate. The present system, despite its simplicity, demonstrated for the first time logically reversible function of the enzyme system transduced electronically with the semiconductor devices. The biomolecular realization of a CNOT gate interfaced with semiconductors is promising for integration into complex biomolecular networks and future biosensor/biomedical applications.}, 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{WernerMiyamotoWagneretal.2017, author = {Werner, Frederik and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {Lateral resolution enhancement of pulse-driven light-addressable potentiometric sensor}, series = {Sensor and Actuators B: Chemical}, volume = {248}, journal = {Sensor and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2017.02.057}, pages = {961 -- 965}, year = {2017}, abstract = {To study chemical and biological processes, spatially resolved determination of the concentrations of one or more analyte species is of distinct interest. With a light-addressable potentiometric sensor (LAPS), chemical images can be created, which visualize the concentration distribution above the sensor plate. One important challenge is to achieve a good lateral resolution in order to detect events that take place in a small and limited region. LAPS utilizes a focused light spot to address the measurement region. By moving this light spot along the semiconductor sensor plate, the concentration distribution can be observed. In this study, we show that utilizing a pulse as light excitation instead of a traditionally used continuously modulated light excitation, the lateral resolution can be improved by a factor of 6 or more.}, language = {en} } @article{MiyamotoHayashiSakamotoetal.2017, author = {Miyamoto, Ko-ichiro and Hayashi, Kosuke and Sakamoto, Azuma and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo}, title = {A high-Q resonance-mode measurement of EIS capacitive sensor by elimination of series resistance}, series = {Sensor and Actuators B: Chemical}, volume = {248}, journal = {Sensor and Actuators B: Chemical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-4005}, doi = {10.1016/j.snb.2017.03.002}, pages = {1006 -- 1010}, year = {2017}, abstract = {An EIS capacitive sensor is a semiconductor-based potentiometric sensor, which is sensitive to the ion concentration or pH value of the solution in contact with the sensing surface. To detect a small change in the ion concentration or pH, a small capacitance change must be detected. Recently, a resonance-mode measurement was proposed, in which an inductor was connected to the EIS capacitive sensor and the resonant frequency was correlated with the pH value. In this study, the Q factor of the resonant circuit was enhanced by canceling the internal resistance of the reference electrode and the internal resistance of the inductor coil with the help of a bypass capacitor and a negative impedance converter, respectively. 1\% variation of the signal in the developed system corresponded to a pH change of 3.93 mpH, which was about 1/12 of the conventional method, suggesting a better performance in detection of a small pH change.}, language = {en} }