@article{NickJoshiSchneideretal.2012, author = {Nick, Christoph and Joshi, Ravi and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Three-Dimensional Carbon Nanotube Electrodes for Extracellular Recording of Cardiac Myocytes}, series = {Biointerphases, 2012}, volume = {7}, journal = {Biointerphases, 2012}, publisher = {Springer-Verl.}, doi = {10.1007/s13758-012-0058-2}, pages = {58}, year = {2012}, abstract = {Three-Dimensional Carbon Nanotube Electrodes for Extracellular Recording of Cardiac Myocytes}, subject = {Kohlenstoff-Nanor{\"o}hre}, language = {en} } @article{KoerbitzerKraussBelleetal.2019, author = {K{\"o}rbitzer, Berit Silke and Krauß, Peter and Belle, Stefan and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Electrochemical Characterization of Graphene Microelectrodes for Biological Applications}, series = {ChemNanoMat}, volume = {2019}, journal = {ChemNanoMat}, number = {5:4}, doi = {10.1002/cnma.201800652}, pages = {427 -- 435}, year = {2019}, abstract = {Graphene is a promising material both as a coating for existing neural electrodes as well as for transparent electrodes made exclusively from graphene. We studied graphene-based microelectrodes by investigating their recording and stimulation properties in order to evaluate their suitability for neuronal implants. In this work, we compare three different electrode material compositions. Microelectrode arrays (MEA) with an electrode size of about 700 μm2 were prepared of gold, graphene on gold, and plain graphene on glass substrate. In order to reduce polymer contamination during graphene transfer, we employed a polymer-free transfer and lift-off process. Impedance studies revealed a value of 2.3 MΩ at 1 kHz for plain, and 0.88 MΩ for graphene on gold. Neuronal recording experiments showed a sufficient SNR for both graphene-based materials and a stable impedance, unaffected by surface degradation metal electrodes are known for. Stimulation measurements yielded a charge injection capacity of 0.15 mC/cm2 using biphasic pulses of 1 ms and 1 μA transparent graphene electrodes. Cyclic voltammetry revealed a large voltage range of -1.4 V to +1.6 V before water electrolysis occurs. Graphene-coated gold microelectrodes show enhanced recording properties, whereas plain graphene electrodes might be better suited for stimulation applications.}, subject = {Mikroelektrode}, language = {en} } @article{NickYadavJoshietal.2015, author = {Nick, Christoph and Yadav, Sandeep and Joshi, Ravi and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {A three-dimensional microelectrode array composed of vertically aligned ultra-dense carbon nanotube networks}, series = {Applied Physics Letters}, volume = {2015}, journal = {Applied Physics Letters}, number = {107}, doi = {10.1063/1.4926330}, pages = {1 -- 1}, year = {2015}, abstract = {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.}, subject = {Mikroelektrode}, language = {en} } @inproceedings{NickThielemannJoshietal.2011, author = {Nick, Christoph and Thielemann, Christiane and Joshi, Ravi and Schneider, J{\"o}rg}, title = {Niedrigtemperatur-Transfer von vertikal ausgerichteten Kohlenstoff Nanor{\"o}hren auf Mikrostrukturen}, series = {Mikro-Nano-Integration - 3. GMM-Workshop, Stuttgart, Deutschland, 2011}, booktitle = {Mikro-Nano-Integration - 3. GMM-Workshop, Stuttgart, Deutschland, 2011}, pages = {5}, year = {2011}, abstract = {Vertikal angeordnete Kohlenstoff Nanor{\"o}hren (engl. vertically aligned carbon nanotubes; VA-CNT) k{\"o}nnen 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 m{\"u}ssen 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 f{\"u}hrt, 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 Nanor{\"o}hren bleibt dabei erhalten. Eine leitende Verbindung kann durch ein leitf{\"a}higes, bio-kompatibles Polymer gew{\"a}hrleistet werden, was eine Erweiterung des Einsatzbereichs auf Life-Science Applikationen erlauben w{\"u}rde.}, subject = {Kohlenstoff-Nanor{\"o}hre}, language = {de} } @inproceedings{YilmazogluAlDaffaieHartnageletal.2012, author = {Yilmazoglu, Oktay and Al-Daffaie, Shihab and Hartnagel, Hans and Joshi, Ravi and Yadav, Sandeep and Schneider, J{\"o}rg and Nick, Christoph and Thielemann, Christiane}, title = {CNT photocathodes based on GaAs high-frequency photoswitches}, series = {25th International Vacuum Nanoelectronics Conference, 9 - 13 July 2012, Jeju, South Korea}, booktitle = {25th International Vacuum Nanoelectronics Conference, 9 - 13 July 2012, Jeju, South Korea}, doi = {10.1109/IVNC.2012.6316840}, year = {2012}, abstract = {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.}, subject = {Kohlenstoff-Nanor{\"o}hre}, language = {en} } @article{NickJoshiSchneideretal.2012, author = {Nick, Christoph and Joshi, Ravi and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Low Temperature Substrate Transfer Technique for 3D Vertically Aligned Carbon Nanotube Architectures}, series = {International Journal of Surface Science and Engineering}, volume = {6}, journal = {International Journal of Surface Science and Engineering}, number = {3}, doi = {10.1504/IJSURFSE.2012.049057}, pages = {246 -- 246}, year = {2012}, subject = {Kohlenstoff-Nanor{\"o}hre}, language = {en} } @inproceedings{NickJoshiSchlaaketal.2011, author = {Nick, Christoph and Joshi, Ravi and Schlaak, Helmut and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Multi electrode array with carbon nanotube electrodes for the extra-cellular detection of action potentials}, series = {MikroSystemTechnik Kongress 2011, Darmstadt}, booktitle = {MikroSystemTechnik Kongress 2011, Darmstadt}, year = {2011}, subject = {Mehrfachelektrode}, language = {en} } @article{NickYadavJoshietal.2014, author = {Nick, Christoph and Yadav, Sandeep and Joshi, Ravi and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Growth of Cortical Neurons Grown on Randomly Oriented and Vertically Aligned Dense Carbon Nanotube Networks}, series = {Beilstein Journal of Nanotechnology}, volume = {5}, journal = {Beilstein Journal of Nanotechnology}, pages = {1575 -- 1579}, year = {2014}, subject = {Nervenzelle}, language = {en} } @inproceedings{KoerbitzerKraussNicketal.2015, author = {K{\"o}rbitzer, Berit Silke and Krauß, Peter and Nick, Christoph and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Graphene electrodes for recording and stimulation of neural cells}, series = {ICREA Workshop on Graphene Nanobiosensors}, booktitle = {ICREA Workshop on Graphene Nanobiosensors}, address = {Barcelona, Spanien}, year = {2015}, subject = {Nervenzelle}, language = {en} } @inproceedings{KoerbitzerKraussSchneideretal.2016, author = {K{\"o}rbitzer, Berit Silke and Krauß, Peter and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {Characterization Of Graphene-Coated Microelectrode Arrays For Recording And Stimulation Of Neuronal Cells}, series = {Frontiers}, volume = {2016}, booktitle = {Frontiers}, number = {MEA Meeting 2016}, doi = {10.3389/conf.fnins.2016.93.00013}, year = {2016}, subject = {Mikroelektrode}, language = {en} } @inproceedings{NickHeinleinSchneideretal.2012, author = {Nick, Christoph and Heinlein, Thorsten and Schneider, J{\"o}rg and Thielemann, Christiane}, title = {3D Carbon Nanotube Electrodes for Sensing of Neural Activity}, series = {Elsevier World Congress on Biosensors}, booktitle = {Elsevier World Congress on Biosensors}, address = {Cancun, Mexiko}, year = {2012}, subject = {Kohlenstoff-Nanor{\"o}hre}, language = {en} }