@article{JahnkeRousselHombachetal.2016, author = {Jahnke, Siegfried and Roussel, Johanna and Hombach, Thomas and Kochs, Johannes and Fischbach, Andreas and Huber, Gregor and Scharr, Hanno}, title = {phenoSeeder - A robot system for automated handling and phenotyping of individual seeds}, series = {Plant physiology}, volume = {172}, journal = {Plant physiology}, number = {3}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0032-0889}, doi = {10.1104/pp.16.01122}, pages = {1358 -- 1370}, year = {2016}, abstract = {The enormous diversity of seed traits is an intriguing feature and critical for the overwhelming success of higher plants. In particular, seed mass is generally regarded to be key for seedling development but is mostly approximated by using scanning methods delivering only two-dimensional data, often termed seed size. However, three-dimensional traits, such as the volume or mass of single seeds, are very rarely determined in routine measurements. Here, we introduce a device named phenoSeeder, which enables the handling and phenotyping of individual seeds of very different sizes. The system consists of a pick-and-place robot and a modular setup of sensors that can be versatilely extended. Basic biometric traits detected for individual seeds are two-dimensional data from projections, three-dimensional data from volumetric measures, and mass, from which seed density is also calculated. Each seed is tracked by an identifier and, after phenotyping, can be planted, sorted, or individually stored for further evaluation or processing (e.g. in routine seed-to-plant tracking pipelines). By investigating seeds of Arabidopsis (Arabidopsis thaliana), rapeseed (Brassica napus), and barley (Hordeum vulgare), we observed that, even for apparently round-shaped seeds of rapeseed, correlations between the projected area and the mass of seeds were much weaker than between volume and mass. This indicates that simple projections may not deliver good proxies for seed mass. Although throughput is limited, we expect that automated seed phenotyping on a single-seed basis can contribute valuable information for applications in a wide range of wild or crop species, including seed classification, seed sorting, and assessment of seed quality.}, language = {en} } @inproceedings{BaeckerKochGeigeretal.2016, author = {B{\"a}cker, Matthias and Koch, C. and Geiger, F. and Eber, F. and Gliemann, H. and Poghossian, Arshak and Sch{\"o}ning, Michael Josef}, title = {A New Class of Biosensors Based on Tobacco Mosaic Virus and Coat Proteins as Enzyme Nanocarrier}, series = {Procedia Engineering}, volume = {Vol. 168}, booktitle = {Procedia Engineering}, issn = {1877-7058}, doi = {10.1016/j.proeng.2016.11.228}, pages = {618 -- 621}, year = {2016}, language = {en} } @inproceedings{PoghossianBronderSchejaetal.2016, author = {Poghossian, Arshak and Bronder, Thomas and Scheja, S. and Wu, Chunsheng and Metzger-Boddien, C. and Keusgen, M. and Sch{\"o}ning, Michael Josef}, title = {Label-free Electrostatic Detection of DNA Amplification by PCR Using Capacitive Field-effect Devices}, series = {Procedia Engineering}, volume = {Vol. 168}, booktitle = {Procedia Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1877-7058}, doi = {10.1016/j.proeng.2016.11.512}, pages = {514 -- 517}, year = {2016}, abstract = {A capacitive field-effect EIS (electrolyte-insulator-semiconductor) sensor modified with a positively charged weak polyelectrolyte of poly(allylamine hydrochloride) (PAH)/single-stranded probe DNA (ssDNA) bilayer has been used for a label-free electrostatic detection of pathogen-specific DNA amplification via polymerase chain reaction (PCR). The sensor is able to distinguish between positive and negative PCR solutions, to detect the existence of target DNA amplicons in PCR samples and thus, can be used as tool for a quick verification of DNA amplification and the successful PCR process.}, language = {en} } @inproceedings{DroszezSannoGoldmannetal.2016, author = {Droszez, Anna and Sanno, Maximilian and Goldmann, Jan-Peter and Albracht, Kirsten and Br{\"u}ggemann, Gerd-Peter and Braunstein, Bjoern}, title = {Differences between take-off behavior during vertical jumps and two artistic elements}, series = {34th International Conference of Biomechanics in Sport, Tsukuba, Japan, July 18-22, 2016}, booktitle = {34th International Conference of Biomechanics in Sport, Tsukuba, Japan, July 18-22, 2016}, issn = {1999-4168}, pages = {577 -- 580}, year = {2016}, language = {en} } @article{NgamgaBialonskiMarwanetal.2016, author = {Ngamga, Eulalie Joelle and Bialonski, Stephan and Marwan, Norbert and Kurths, J{\"u}rgen and Geier, Christian and Lehnertz, Klaus}, title = {Evaluation of selected recurrence measures in discriminating pre-ictal and inter-ictal periods from epileptic EEG data}, series = {Physics Letters A}, volume = {380}, journal = {Physics Letters A}, number = {16}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0375-9601}, doi = {10.1016/j.physleta.2016.02.024}, pages = {1419 -- 1425}, year = {2016}, abstract = {We investigate the suitability of selected measures of complexity based on recurrence quantification analysis and recurrence networks for an identification of pre-seizure states in multi-day, multi-channel, invasive electroencephalographic recordings from five epilepsy patients. We employ several statistical techniques to avoid spurious findings due to various influencing factors and due to multiple comparisons and observe precursory structures in three patients. Our findings indicate a high congruence among measures in identifying seizure precursors and emphasize the current notion of seizure generation in large-scale epileptic networks. A final judgment of the suitability for field studies, however, requires evaluation on a larger database.}, language = {en} } @article{BialonskiCaronSchloenetal.2016, author = {Bialonski, Stephan and Caron, David A. and Schloen, Julia and Feudel, Ulrike and Kantz, Holger and Moorthi, Stefanie D.}, title = {Phytoplankton dynamics in the Southern California Bight indicate a complex mixture of transport and biology}, series = {Journal of Plankton Research}, volume = {38}, journal = {Journal of Plankton Research}, number = {4}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1464-3774}, doi = {10.1093/plankt/fbv122}, pages = {1077 -- 1091}, year = {2016}, abstract = {The stimulation and dominance of potentially harmful phytoplankton taxa at a given locale and time are determined by local environmental conditions as well as by transport to or from neighboring regions. The present study investigated the occurrence of common harmful algal bloom (HAB) taxa within the Southern California Bight, using cross-correlation functions to determine potential dependencies between HAB taxa and environmental factors, and potential links to algal transport via local hydrography and currents. A simulation study, in which Lagrangian particles were released, was used to assess travel times due to advection by prevailing ocean currents in the bight. Our results indicate that transport of some taxa may be an important mechanism for the expansion of their distributions into other regions, which was supported by mean travel times derived from our simulation study and other literature on ocean currents in the Southern California Bight. In other cases, however, phytoplankton dynamics were rather linked to local environmental conditions, including coastal upwelling events. Overall, our study shows that complex current patterns in the Southern California Bight may contribute significantly to the formation and expansion of HABs in addition to local environmental factors determining the spatiotemporal dynamics of phytoplankton blooms.}, language = {en} } @incollection{Bialonski2016, author = {Bialonski, Stephan}, title = {Are interaction clusters in epileptic networks predictive of seizures?}, series = {Epilepsy: The Intersection of Neurosciences, Biology, Mathematics, Engineering, and Physics}, booktitle = {Epilepsy: The Intersection of Neurosciences, Biology, Mathematics, Engineering, and Physics}, publisher = {CRC Press}, isbn = {978-143983886-0}, pages = {349 -- 355}, year = {2016}, language = {en} } @article{AimenovaDigelEshibaev2016, author = {Aimenova, Zh. E. and Digel, Ilya and Eshibaev, А. А.}, title = {Dynamics of accumulation of lagochirzin in Lagochilus setulosus phytomass during the growing season and also features of its cultivation in the conditions of a typical sierozem}, series = {KazNU Bulletin. Biology series}, volume = {69}, journal = {KazNU Bulletin. Biology series}, number = {4}, publisher = {Al-Farabi Kazakh National University}, address = {Almaty}, issn = {1563-0218}, pages = {4 -- 11}, year = {2016}, abstract = {L.setulosus is offered for creation of biopreparation «Setulin», possesing he- mostatic action, the basic reactant of biopreparation is diterpen - lagochirzin. Results under the maintenance and dynamics of diterpen lagochirzin accumula- tion in various parts of L.setulosus are presented: in roots, stalks, leaves, flowers and calyx lobes during the growing season, and also results on conditions of cultivation L.setulosus in the conditions of a typical sierozem are resulted. From the obtained data is visible, that the given species of a plant is endemic. It is established, that dynamics of accumulation of lagochirzin in phytomass accrues from the beginning to the middle of the growing season. The chemical analysis of L.setulosus on a localization of lagochirzin in various organs of a plant, has shown, that the greatest quantity of lagochirzin collects in calyx lobes of the plants. Also it is established, that L.setulosus can be cultivated in the conditions of the typical sierozem, a mineral food is necessary for the given species of plants of Lagochilus genus, except nitric fertilizers. Comparative studying of wild-growing and cultural forms of L.setulosus has shown, that in the cultivated phytomass of plants the maintenance of lagochirzin on 17-20 \% higher than in the wild-growing species.}, language = {en} } @article{TuraliyevaYeshibaevSaparbekovaetal.2016, author = {Turaliyeva, M. and Yeshibaev, A. and Saparbekova, A. and Akynova, L. and Abildayeva, R. and Sadenova, M. and Sartayeva, K. and Schieffer, Andre and Digel, Ilya}, title = {Species composition and injuriousness of stranger xylophilous fauna affecting indigenous urban dendroflora of Central Asia}, series = {Asian journal of microbiology, biotechnology \& environmental sciences : AJMBES}, volume = {18}, journal = {Asian journal of microbiology, biotechnology \& environmental sciences : AJMBES}, number = {2}, publisher = {EM International}, issn = {0972-3005}, pages = {359 -- 366}, year = {2016}, abstract = {At the present time, one of the most serious environmental problems of Central Asia and South Kazakhstan is the ongoing large-scale deterioration of principal urban tree populations. Several major centers of massive spread of invasive plant pests have been found in urban dendroflora of this region. The degree of damage of seven most wide-spread aboriginal tree species was found to range from 21.4±1.1 to 85.4±1.8\%. In particular, the integrity of the native communities of sycamore (Platanus spp.), willow (Salix spp.), poplar (Populus spp.) and elm (Ulmus spp.) is highly endangered. Our taxonomic analysis of the most dangerous tree pests of the region has revealed them as neobiontic xylophilous insects such as Cossus cossus L. (Order: Lepidoptera L.) Monochamus urussovi Fisch., Monochamus sutor L., Acanthocinus aedelis L. and {\~N}etonia aureate L. (Order: Coleoptera L.). We relate the origin of this threatening trend with the import of industrial wood in the mid 90’s of the last century that was associated with high degree of the constructional work in the region. Because of the absence of efficient natural predators of the pest species, the application of microbiological methods of the pest control and limitation is suggested.}, language = {en} } @article{AlbannaConzenWeissetal.2016, author = {Albanna, W. and Conzen, C. and Weiss, M. and Clusmann, H. and Fuest, M. and Mueller, M. and Brockmann, M.A. and Vilser, W. and Schmidt-Trucks{\"a}ss, A. and Hoellig, A. and Seiz, M. and Thom{\´e}, C. and Kotliar, Konstantin and Schubert, G.A.}, title = {Retinal Vessel Analysis (RVA) in the context of subarachnoid hemorrhage: A proof of concept study}, series = {PLoS ONE}, volume = {11}, journal = {PLoS ONE}, number = {7}, publisher = {PLOS}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0158781}, pages = {13 Seiten}, year = {2016}, abstract = {Background Timely detection of impending delayed cerebral ischemia after subarachnoid hemorrhage (SAH) is essential to improve outcome, but poses a diagnostic challenge. Retinal vessels as an embryological part of the intracranial vasculature are easily accessible for analysis and may hold the key to a new and non-invasive monitoring technique. This investigation aims to determine the feasibility of standardized retinal vessel analysis (RVA) in the context of SAH. Methods In a prospective pilot study, we performed RVA in six patients awake and cooperative with SAH in the acute phase (day 2-14) and eight patients at the time of follow-up (mean 4.6±1.7months after SAH), and included 33 age-matched healthy controls. Data was acquired using a manoeuvrable Dynamic Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and neurovascular coupling. Results Image quality was satisfactory in the majority of cases (93.3\%). In the acute phase after SAH, retinal arteries were significantly dilated when compared to the control group (124.2±4.3MU vs 110.9±11.4MU, p<0.01), a difference that persisted to a lesser extent in the later stage of the disease (122.7±17.2MU, p<0.05). Testing for neurovascular coupling showed a trend towards impaired primary vasodilation and secondary vasoconstriction (p = 0.08, p = 0.09 resp.) initially and partial recovery at the time of follow-up, indicating a relative improvement in a time-dependent fashion. Conclusion RVA is technically feasible in patients with SAH and can detect fluctuations in vessel diameter and autoregulation even in less severely affected patients. Preliminary data suggests potential for RVA as a new and non-invasive tool for advanced SAH monitoring, but clinical relevance and prognostic value will have to be determined in a larger cohort.}, language = {en} } @article{KolditzAlbinAbeletal.2016, author = {Kolditz, Melanie and Albin, Thivaharan and Abel, Dirk and Fasse, Alessandro and Br{\"u}ggemann, Gert-Peter and Albracht, Kirsten}, title = {Evaluation of foot position and orientation as manipulated variables to control external knee adduction moments in leg extension training}, series = {Computer methods and programs in biomedicine}, volume = {171}, journal = {Computer methods and programs in biomedicine}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-2607}, doi = {10.1016/j.cmpb.2016.09.005}, pages = {81 -- 86}, year = {2016}, abstract = {Background and Objective Effective leg extension training at a leg press requires high forces, which need to be controlled to avoid training-induced damage. In order to avoid high external knee adduction moments, which are one reason for unphysiological loadings on knee joint structures, both training movements and the whole reaction force vector need to be observed. In this study, the applicability of lateral and medial changes in foot orientation and position as possible manipulated variables to control external knee adduction moments is investigated. As secondary parameters both the medio-lateral position of the center of pressure and the frontal-plane orientation of the reaction force vector are analyzed. Methods Knee adduction moments are estimated using a dynamic model of the musculoskeletal system together with the measured reaction force vector and the motion of the subject by solving the inverse kinematic and dynamic problem. Six different foot conditions with varying positions and orientations of the foot in a static leg press are evaluated and compared to a neutral foot position. Results Both lateral and medial wedges under the foot and medial and lateral shifts of the foot can influence external knee adduction moments in the presented study with six healthy subjects. Different effects are observed with the varying conditions: the pose of the leg is changed and the direction and center of pressure of the reaction force vector is influenced. Each effect results in a different direction or center of pressure of the reaction force vector. Conclusions The results allow the conclusion that foot position and orientation can be used as manipulated variables in a control loop to actively control knee adduction moments in leg extension training.}, 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{YoshinobuMiyamotoWagneretal.2015, author = {Yoshinobu, Tatsuo and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef}, title = {Recent developments of chemical imaging sensor systems based on the principle of the light-addressable potentiometric sensor}, 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.2014.09.002}, pages = {926 -- 932}, year = {2015}, abstract = {The light-addressable potentiometric sensor (LAPS) is an electrochemical sensor with a field-effect structure to detect the variation of the Nernst potential at its sensor surface, the measured area on which is defined by illumination. Thanks to this light-addressability, the LAPS can be applied to chemical imaging sensor systems, which can visualize the two-dimensional distribution of a particular target ion on the sensor surface. Chemical imaging sensor systems are expected to be useful for analysis of reaction and diffusion in various electrochemical and biological samples. Recent developments of LAPS-based chemical imaging sensor systems, in terms of the spatial resolution, measurement speed, image quality, miniaturization and integration with microfluidic devices, are summarized and discussed.}, language = {en} } @incollection{FrotscherGossmannRaatschenetal.2015, author = {Frotscher, Ralf and Goßmann, Matthias and Raatschen, Hans-J{\"u}rgen and Temiz Artmann, Ayseg{\"u}l and Staat, Manfred}, title = {Simulation of cardiac cell-seeded membranes using the edge-based smoothed FEM}, series = {Shell and membrane theories in mechanics and biology. (Advanced structured materials ; 45)}, booktitle = {Shell and membrane theories in mechanics and biology. (Advanced structured materials ; 45)}, publisher = {Springer}, address = {Heidelberg}, isbn = {978-3-319-02534-6 ; 978-3-319-02535-3}, pages = {187 -- 212}, year = {2015}, abstract = {We present an electromechanically coupled Finite Element model for cardiac tissue. It bases on the mechanical model for cardiac tissue of Hunter et al. that we couple to the McAllister-Noble-Tsien electrophysiological model of purkinje fibre cells. The corresponding system of ordinary differential equations is implemented on the level of the constitutive equations in a geometrically and physically nonlinear version of the so-called edge-based smoothed FEM for plates. Mechanical material parameters are determined from our own pressure-deflection experimental setup. The main purpose of the model is to further examine the experimental results not only on mechanical but also on electrophysiological level down to ion channel gates. Moreover, we present first drug treatment simulations and validate the model with respect to the experiments.}, language = {en} } @article{PoghossianBaeckerMayeretal.2015, author = {Poghossian, Arshak and B{\"a}cker, Matthias and Mayer, Dirk and Sch{\"o}ning, Michael Josef}, title = {Gating capacitive field-effect sensors by the charge of nanoparticle/molecule hybrids}, series = {Nanoscale}, journal = {Nanoscale}, publisher = {Royal Society of Chemistry (RSC)}, address = {Cambridge}, issn = {2040-3372 (E-Journal); 2040-3364 (Print)}, doi = {10.1039/C4NR05987E}, pages = {1023 -- 1031}, year = {2015}, 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{MuribYeapMartensetal.2015, author = {Murib, M. S. and Yeap, W. S. and Martens, D. and Liu, X. and Bienstman, P. and Fahlman, M. and Sch{\"o}ning, Michael Josef and Michiels, L. and Haenen, K. and Serpeng{\"u}zel, A. and Wagner, Patrick}, title = {Photonic studies on polymer-coated sapphire-spheres : a model system for biological ligands}, series = {Sensors and actuators A: Physical}, volume = {222}, journal = {Sensors and actuators A: Physical}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-3069 (E-Journal); 0924-4247 (Print)}, doi = {10.1016/j.sna.2014.11.024}, pages = {212 -- 219}, year = {2015}, abstract = {In this study we show an optical biosensor concept, based on elastic light scattering from sapphire microspheres. Transmitted and elastic scattering intensity of the microspheres (radius 500 μm, refractive index 1.77) on an optical fiber half coupler is analyzed at 1510 nm. The 0.43 nm angular mode spacing of the resonances is comparable to the angular mode spacing value estimated using the optical size of the microsphere. The spectral linewidths of the resonances are in the order of 0.01 nm, which corresponds to quality factors of approximately 105. A polydopamine layer is used as a functionalizing agent on sapphire microspherical resonators in view of biosensor implementation. The varying layer thickness on the microsphere is determined as a function of the resonance wavelength shift. It is shown that polymer functionalization has a minor effect on the quality factor. This is a promising step toward the development of an optical biosensor.}, language = {en} } @incollection{TranStaat2015, author = {Tran, Thanh Ngoc and Staat, Manfred}, title = {Uncertainty multimode failure and shakedown analysis of shells}, series = {Direct methods for limit and shakedown analysis of structures / eds. Paolo Fuschi ...}, booktitle = {Direct methods for limit and shakedown analysis of structures / eds. Paolo Fuschi ...}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-12927-3 (print) ; 978-3-319-12928-0 (online)}, doi = {10.1007/978-3-319-12928-0_14}, pages = {279 -- 298}, year = {2015}, abstract = {This paper presents a numerical procedure for reliability analysis of thin plates and shells with respect to plastic collapse or to inadaptation. The procedure involves a deterministic shakedown analysis for each probabilistic iteration, which is based on the upper bound approach and the use of the exact Ilyushin yield surface. Probabilistic shakedown analysis deals with uncertainties originated from the loads, material strength and thickness of the shell. Based on a direct definition of the limit state function, the calculation of the failure probability may be efficiently solved by using the First and Second Order Reliability Methods (FORM and SORM). The problem of reliability of structural systems (series systems) is handled by the application of a special technique which permits to find all the design points corresponding to all the failure modes. Studies show, in this case, that it improves considerably the FORM and SORM results.}, language = {en} } @article{WuBronderPoghossianetal.2015, author = {Wu, Chunsheng and Bronder, Thomas and Poghossian, Arshak and Werner, Frederik and Sch{\"o}ning, Michael Josef}, title = {Label-free detection of DNA using light-addressable potentiometric sensor modified with a positively charged polyelectrolyte layer}, series = {Nanoscale}, volume = {14}, journal = {Nanoscale}, number = {7}, publisher = {Royal Society of Chemistry (RSC)}, address = {Cambridge}, doi = {10.1039/C4NR07225A}, pages = {6143 -- 6150}, year = {2015}, abstract = {A multi-spot (16 spots) light-addressable potentiometric sensor (MLAPS) consisting of an Al-p-Si-SiO2 structure modified with a weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was applied for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge for the first time. To achieve a preferentially flat orientation of DNA strands and thus, to reduce the distance between the DNA charge and MLAPS surface, the negatively charged probe single-stranded DNAs (ssDNA) were electrostatically adsorbed onto the positively charged PAH layer using a simple layer-by-layer (LbL) technique. In this way, more DNA charge can be positioned within the Debye length, yielding a higher sensor signal. The surface potential changes in each spot induced due to the surface modification steps (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), non-specific adsorption of mismatched ssDNA) were determined from the shifts of photocurrent-voltage curves along the voltage axis. A high sensor signal of 83 mV was registered after immobilization of probe ssDNA onto the PAH layer. The hybridization signal increases from 5 mV to 32 mV with increasing the concentration of cDNA from 0.1 nM to 5 μM. In contrast, a small signal of 5 mV was recorded in the case of non-specific adsorption of fully mismatched ssDNA (5 μM). The obtained results demonstrate the potential of the MLAPS in combination with the simple and rapid LbL immobilization technique as a promising platform for the future development of multi-spot light-addressable label-free DNA chips with direct electrical readout.}, language = {en} } @article{BegingLeinhosJablonskietal.2015, author = {Beging, Stefan and Leinhos, Marcel and Jablonski, Melanie and Poghossian, Arshak and Sch{\"o}ning, Michael Josef}, title = {Studying the spatially resolved immobilisation of enzymes on a capacitive field-effect structure by means of nano-spotting}, series = {Physica status solidi (a)}, volume = {212}, journal = {Physica status solidi (a)}, number = {6}, publisher = {Wiley}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201431891}, pages = {1353 -- 1358}, year = {2015}, language = {en} }