TY - JOUR A1 - Nick, Christoph A1 - Joshi, Ravi A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - Three-Dimensional Carbon Nanotube Electrodes for Extracellular Recording of Cardiac Myocytes JF - Biointerphases, 2012 N2 - Three-Dimensional Carbon Nanotube Electrodes for Extracellular Recording of Cardiac Myocytes KW - nanotube electrodes KW - Kohlenstoff-Nanoröhre Y1 - 2012 U6 - https://doi.org/10.1007/s13758-012-0058-2 VL - 7 SP - 58 PB - Springer-Verl. ER - TY - THES A1 - Nick, Christoph T1 - Mikrointegrierte Nanostrukturen mit hohem Aspektverhältnis als neuronale Schnittstelle KW - Neuronales Netz KW - Mikroelektrode Y1 - 2015 UR - http://tuprints.ulb.tu-darmstadt.de/4595/7/Dissertation%20-%20Christoph%20Nick.pdf ER - TY - JOUR A1 - Nick, Christoph A1 - Yadav, Sandeep A1 - Joshi, Ravi A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - A three-dimensional microelectrode array composed of vertically aligned ultra-dense carbon nanotube networks JF - Applied Physics Letters N2 - Electrodes based on carbon nanotubes are a promising approach to manufacture highly sensitive sensors with a low limit of signal detection and a high signal-to-noise ratio. This is achieved by dramatically increasing the electrochemical active surface area without increasing the overall geometrical dimensions. Typically, carbon nanotube electrodes are nearly planar and composed of randomly distributed carbon nanotube networks having a limited surface gain for a specific geometrical surface area. To overcome this limitation, we have introduced vertically aligned carbon nanotube (VACNT) networks as electrodes, which are arranged in a microelectrode pattern of 60 single electrodes. Each microelectrode features a very high aspect ratio of more than 300 and thus a dramatically increased surface area. These microelectrodes composed of VACNT networks display dramatically decreased impedance over the entire frequency range compared to planar microelectrodes caused by the enormous capacity increase. This is experimentally verified by electrochemical impedance spectroscopy and cyclic voltammetry. KW - Microelectrode arrays KW - Electrochemical impedance spectroscopy KW - Chemical compounds and components KW - Electrolytes KW - Signal processing KW - Mikroelektrode KW - Array KW - Kohlenstoff-Nanoröhre Y1 - 2015 U6 - https://doi.org/10.1063/1.4926330 VL - 2015 IS - 107 SP - 1 EP - 1 ER - TY - JOUR A1 - Nick, Christoph A1 - Daus, Andreas A1 - Bestel, Robert A1 - Goldhammer, Michael A1 - Steger, Frederik A1 - Thielemann, Christiane T1 - DrCell - a software tool for the analysis of cell signals recorded with extracellular microelectrodes JF - Signal processing: an international journal (SPIJ) KW - Mikroelektrode Y1 - 2014 UR - http://www.cscjournals.org/manuscript/Journals/SPIJ/Volume7/Issue2/SPIJ-226.pdf VL - 7 IS - 2 SP - 96 EP - 109 ER - TY - CHAP A1 - Nick, Christoph A1 - Hock, Christina A1 - Emmerich, Florian A1 - Belle, Stefan A1 - Thielemann, Christiane A1 - Asmus, Tim A1 - Loose, Thomas A1 - Wienand, Karlheinz T1 - Ultrathin gold as sensor platform for biomolecules T2 - 2015 International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO), Changchun, China N2 - Due to the increasing number of diabetes patients worldwide there is an enormous need for accurate, fast and someday also continuous or even closed loop monitoring of blood glucose level. More than 50 years after Clark and Lyons proposed the first glucose enzyme electrodes this concept is still widely in use today. Most concepts use the enzyme glucose oxidase (GOx) that reacts with glucose. These reactions cause a current that is proportional to the amount of glucose present at the sensor. Thus, if the sample volume is known, the blood sugar level can be measured. Although these electrodes have been in use for so long they have the disadvantage of a limited shelf time. In this work we present an enzyme free approach for glucose detection applying ultrathin gold films. According to the basic Fuchs-Sondheimer-theory and other more sophisticated models the resistivity of ultrathin metal films is dominated by scattering effects at their surface. Chemical reactions at the metallic surface are expected to change the conductivity properties and thus these changes can be used to detect molecules. This can be done by creating a self-assembled monolayer at the gold surface. When molecules such as glucose bind to the end groups of this layer the electron scattering and thus the conductivity of the film is expected to change. Ultrathin gold films with a thickness of 6 nm show the largest relative change in resistivity and are thus the preferred film thickness for this application. These gold films show a significant change in resistance when model molecules sodium sulfide and dextran are present, whereas the resistance of a platinum reference electrode does not change significantly. KW - ultrathin gold KW - biosensor KW - glucose KW - enzyme free glucose sensor KW - Biosensor KW - Dünne Schicht KW - Gold Y1 - 2015 U6 - https://doi.org/10.1109/3M-NANO.2015.7425462 ER - TY - CHAP A1 - Nick, Christoph A1 - Thielemann, Christiane A1 - Joshi, Ravi A1 - Schneider, Jörg T1 - Niedrigtemperatur-Transfer von vertikal ausgerichteten Kohlenstoff Nanoröhren auf Mikrostrukturen T2 - Mikro-Nano-Integration - 3. GMM-Workshop, Stuttgart, Deutschland, 2011 N2 - Vertikal angeordnete Kohlenstoff Nanoröhren (engl. vertically aligned carbon nanotubes; VA-CNT) können seit einigen Jahren mit hoher Reproduzierbarkeit durch CVD-Verfahren bei 600 °C - 800 °C auf Katalysatorschichten aus Aluminium und Eisen hergestellt werden. Sie zeigen sehr gute Eigenschaften im Bereich der Feldemission, aber auch in sub-µm Vias. Allerdings sind die relativ hohen Temperaturen oft nicht prozesskompatibel und müssen vermieden werden um keine Degradation darunterliegender Strukturen in Kauf zu nehmen. Da die Reduzierung der CVD-Temperaturen beim Wachstum der VA-CNTs unter 600 °C zu hohen Defektraten führt, schlagen wir ein neues Verfahren zum Transfer der VA-CNTs bei niedrigen Temperaturen vor. In einer Kombination aus Flip-Chip- und Stempel-Technik werden hoch geordnete, mikrostrukturierte VA-CNTs auf temperaturempfindliche Substrate aus Kalk-Natron-Glas, Gold oder Kupfer bei Temperaturen von 100 °C transferiert. Die vertikale Struktur der Nanoröhren bleibt dabei erhalten. Eine leitende Verbindung kann durch ein leitfähiges, bio-kompatibles Polymer gewährleistet werden, was eine Erweiterung des Einsatzbereichs auf Life-Science Applikationen erlauben würde. KW - Kohlenstoff-Nanoröhre Y1 - 2011 ER - TY - CHAP A1 - Yilmazoglu, Oktay A1 - Al-Daffaie, Shihab A1 - Hartnagel, Hans A1 - Joshi, Ravi A1 - Yadav, Sandeep A1 - Schneider, Jörg A1 - Nick, Christoph A1 - Thielemann, Christiane T1 - CNT photocathodes based on GaAs high-frequency photoswitches T2 - 25th International Vacuum Nanoelectronics Conference, 9 - 13 July 2012, Jeju, South Korea N2 - A high-frequency photocathode based on carbon nanotube (CNT) blocks on semiisolating GaAs or low-temperature grown GaAs was fabricated and used for electron emission in a diode configuration. The CNT blocks can achieve high currents and current densities of I=0.5 mA and J=28 mA/cm 2 at E=2.1 V/μm, respectively. The photomodulation was achieved with a GaAs photoswitch electrically connected to the bottom of the CNT block emitter. This photocathode can find applications in high frequency tubes and optically driven X-ray sources. KW - Kohlenstoff-Nanoröhre Y1 - 2012 U6 - https://doi.org/10.1109/IVNC.2012.6316840 ER - TY - JOUR A1 - Nick, Christoph A1 - Schlaak, Helmut A1 - Thielemann, Christiane T1 - Simulation and Measurement of Neuroelectrodes' Characteristics with Integrated High Aspect Ratio Nano Structures JF - AIMS Journal N2 - Improving the interface between electrodes and neurons has been the focus of research for the last decade. Neuroelectrodes should show small geometrical surface area and low impedance for measuring and high charge injection capacities for stimulation. Increasing the electrochemically active surface area by using nanoporous electrode material or by integrating nanostructures onto planar electrodes is a common approach to improve this interface. In this paper a simulation approach for neuro electrodes' characteristics with integrated high aspect ratio nano structures based on a point-contact-model is presented. The results are compared with experimental findings conducted with real nanostructured microelectrodes. In particular, effects of carbon nanotubes and gold nanowires integrated onto microelectrodes are described. Simulated and measured impedance properties are presented and its effects onto the transfer function between the neural membrane potential and the amplifier output signal are studied based on the point-contact-model. Simulations show, in good agreement with experimental results, that electrode impedances can be dramatically reduced by the integration of high aspect ratio nanostructures such as gold nanowires and carbon nanotubes. This lowers thermal noise and improves the signal-to-noise ratio for measuring electrodes. It also may increase the adhesion of cells to the substrate and thus increase measurable signal amplitudes. KW - Neuronales Netz KW - Mikroelektrode Y1 - 2015 U6 - https://doi.org/10.3934/matersci.2015.3.189 VL - 2015 IS - 2 SP - 189 EP - 202 ER - TY - JOUR A1 - Ciba, Manuel A1 - Bestel, Robert A1 - Nick, Christoph A1 - Ferraz de Arruda, Guilherme A1 - Peron, Thomas A1 - Henrique, Comin César A1 - da Fontoura Costa, Luciano A1 - Aparecido Rodrigues, Francisco A1 - Thielemann, Christiane T1 - Comparison of Different Spike Train Synchrony Measures Regarding Their Robustness to Erroneous Data from Bicuculline-Induced Epileptiform Activity JF - Neural Computation N2 - As synchronized activity is associated with basic brain functions and pathological states, spike train synchrony has become an important measure to analyze experimental neuronal data. Many measures of spike train synchrony have been proposed, but there is no gold standard allowing for comparison of results from different experiments. This work aims to provide guidance on which synchrony measure is best suited to quantify the effect of epileptiform-inducing substances (e.g., bicuculline, BIC) in in vitro neuronal spike train data. Spike train data from recordings are likely to suffer from erroneous spike detection, such as missed spikes (false negative) or noise (false positive). Therefore, different timescale-dependent (cross-correlation, mutual information, spike time tiling coefficient) and timescale-independent (Spike-contrast, phase synchronization (PS), A-SPIKE-synchronization, A-ISI-distance, ARI-SPIKE-distance) synchrony measures were compared in terms of their robustness to erroneous spike trains. For this purpose, erroneous spike trains were generated by randomly adding (false positive) or deleting (false negative) spikes (in silico manipulated data) from experimental data. In addition, experimental data were analyzed using different spike detection threshold factors in order to confirm the robustness of the synchrony measures. All experimental data were recorded from cortical neuronal networks on microelectrode array chips, which show epileptiform activity induced by the substance BIC. As a result of the in silico manipulated data, Spike-contrast was the only measure that was robust to false-negative as well as false-positive spikes. Analyzing the experimental data set revealed that all measures were able to capture the effect of BIC in a statistically significant way, with Spike-contrast showing the highest statistical significance even at low spike detection thresholds. In summary, we suggest using Spike contrast to complement established synchrony measures because it is timescale independent and robust to erroneous spike trains. KW - Neuronales Netz Y1 - 2020 U6 - https://doi.org/10.1162/neco_a_01277 VL - 32 IS - 3 SP - 1 EP - 25 ER - TY - JOUR A1 - Nick, Christoph A1 - Quednau, Sebastian A1 - Sarwar, Reza A1 - Schlaak, Helmut A1 - Thielemann, Christiane T1 - High Aspect Ratio Gold Nanopillars on Microelectrodes for Neural Interfaces JF - Microsystem Technologies Media KW - nanopillars KW - Neuronales Netz KW - Mikroelektrode Y1 - 2013 UR - http://link.springer.com/article/10.1007%2Fs00542-013-1958-x SN - 0946-7076 IS - 20/10-11 SP - 1849 EP - 1857 ER - TY - CHAP A1 - Nick, Christoph A1 - Bestel, Robert A1 - Steger, Frederik A1 - Thielemann, Christiane T1 - Spike Detection, Sorting and Propagation of Cell Signals Recorded with Extracellular Microelectrodes, Engineering in Medicine and Biology Society T2 - IEMBS’13, 35th Annual International Conference of the IEEE KW - Pulsverarbeitendes neuronales Netz KW - Zellwachstum Y1 - 2013 ER - TY - JOUR A1 - Nick, Christoph A1 - Joshi, Ravi A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - Low Temperature Substrate Transfer Technique for 3D Vertically Aligned Carbon Nanotube Architectures JF - International Journal of Surface Science and Engineering KW - nanotube architectures KW - Kohlenstoff-Nanoröhre Y1 - 2012 U6 - https://doi.org/10.1504/IJSURFSE.2012.049057 VL - 6 IS - 3 SP - 246 EP - 246 ER - TY - CHAP A1 - Nick, Christoph A1 - Joshi, Ravi A1 - Schlaak, Helmut A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - Multi electrode array with carbon nanotube electrodes for the extra-cellular detection of action potentials T2 - MikroSystemTechnik Kongress 2011, Darmstadt KW - Mehrfachelektrode KW - Elektrodenarray Y1 - 2014 ER - TY - CHAP A1 - Nick, Christoph A1 - Quednau, Sebastian A1 - Sarwar, Reza A1 - Thielemann, Christiane A1 - Schlaak, Helmut T1 - Fabrication of high aspect ratio gold nanopillars on microelectrodes for the interface with electrogenic cells T2 - HARMNST - 10th international workshop on high aspect ratio micro and nano system technologies, Berlin KW - Mikroelektrode Y1 - 2013 SP - 212 EP - 213 ER - TY - JOUR A1 - Nick, Christoph A1 - Yadav, Sandeep A1 - Joshi, Ravi A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - Growth of Cortical Neurons Grown on Randomly Oriented and Vertically Aligned Dense Carbon Nanotube Networks JF - Beilstein Journal of Nanotechnology KW - Nervenzelle KW - Zellwachstum Y1 - 2014 VL - 5 SP - 1575 EP - 1579 ER - TY - CHAP A1 - Körbitzer, Berit Silke A1 - Krauß, Peter A1 - Nick, Christoph A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - Graphene electrodes for recording and stimulation of neural cells T2 - ICREA Workshop on Graphene Nanobiosensors KW - Nervenzelle KW - Elektrostimulation Y1 - 2015 CY - Barcelona, Spanien ER - TY - CHAP A1 - Nick, Christoph A1 - Lippert, Paul A1 - Quednau, Sebastian A1 - Schlaak, Helmut A1 - Thielemann, Christiane T1 - Gold Nanopillar Microelectrodes on Low Temperature Curing Polyimide for the Interface with Electrogenic Cells T2 - Middle East Conference on Biomedical Engineering KW - Mikroelektrode Y1 - 2014 SN - 978-1-4799-4799-7 VL - 2014 SP - 55 EP - 58 CY - Doha, Qatar ER - TY - CHAP A1 - Nick, Christoph A1 - Quednau, Sebastian A1 - Sarwar, Reza A1 - Thielemann, Christiane A1 - Schlaak, Helmut T1 - Gold-Nanodrähte auf Mikroelektroden zur extrazellulären Ableitung elektrogener Zellen T2 - Mikrosystemtechnik Kongress KW - Mikroelektrode Y1 - 2013 PB - VDE Verlag CY - Aachen, Deutschland ER - TY - CHAP A1 - Stern, Maike A1 - Nick, Christoph A1 - Thielemann, Christiane T1 - A Novel LabVIEW based Multi-Channel Closed-Loop Stimulator T2 - 9th International Meeting on Substrate-Integrated Micro-electrode Arrays KW - LabVIEW KW - Simulation Y1 - 2014 VL - 2014 CY - Reutlingen, Germany ER - TY - CHAP A1 - Nick, Christoph A1 - Schlaak, Helmut A1 - Thielemann, Christiane T1 - PEDOT:PSS coated Gold Nanopillar Micro-electrodes for Neural Interfaces T2 - 4th International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale KW - Mikroelektrode Y1 - 2014 VL - 2014 CY - Taipeh, Taiwan ER - TY - JOUR A1 - Nick, Christoph A1 - Thielemann, Christiane T1 - Are Carbon Nanotube Microelectrodes Manufactured from Dispersion Stable Enough for Neural Interfaces? JF - BioNanoScience KW - Mikroelektrode KW - Neuronales Netz Y1 - 2014 VL - 2014 IS - 4 / 3 SP - 216 EP - 225 ER - TY - CHAP A1 - Nick, Christoph A1 - Heinlein, Thorsten A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - 3D Carbon Nanotube Electrodes for Sensing of Neural Activity T2 - Elsevier World Congress on Biosensors KW - Kohlenstoff-Nanoröhre Y1 - 2012 CY - Cancun, Mexiko ER -