Hippocampal Neurons’ Alignment on Quartz Grooves and Parylene Cues on Quartz Substrate

Alignment and patterning of neurons have great importance in some research fields, especially for regenerative medicine and for the formation of artificial neural networks. Alignment of neurons on quartz grooves and parylene cues on quartz substrate was evaluated in this work. The neurons’ alignment on quartz grooves is considered to be topographical alignment, while the neurons’ alignment on parylene cues on quartz substrate is considered to be chemical alignment. Both quartz grooves’ and parylene cues’ widths were fabricated in a range from 2 µm to 8 µm; quartz grooves’ heights were in a range from 0.25 µm to 4 µm, while parylene cues’ heights were only 0.25 µm. Neurons were dissociated hippocampal neurons from rat E18. Neurons were cultivated on test substrates for 7 days before alignment evaluation. As expected, neurons aligned according to the direction of grooves and cues; however, transversal growth direction was also observed with much smaller tendency. Chemical alignment was found to be more effective than topographical alignment. If parylene cues are thin and distanced enough, then neurons have a tendency to follow the direction of individual parylene cues; however, neurons on quartz grooves have a tendency just to follow a preferable direction than individual quartz grooves

Electrical Characterization of Hydrothermally Synthesized Metal Oxide Nanowires with Regard to Oxygen Adsorption/Desorption Thermodynamics

Hydrothermally synthesized MnO2 nanowires were deposited on gold interdigitated electrode (IDE) chip using dielectrophoresis (DEP). Conductivity of alone-standing MnO2 nanowires was tested both in synthetic air and in nitrogen ambientes. Thermal analysis was performed up to 300°C of bottom-placed heater (under the IDE chip). MnO2 material properties, such as semiconductor type, vacancies concentration and relative permittivity were evaluated by means of impedance and Mott-Schottky analyses.

Modification of Working Electrode Surface with Carbon Nanotubes as an Electrochemical Sensor for Estimation of Melting Points of DNA

Screen-printed with three electrode system was used in this study. A working electrode has been printed from carbon nanotubes based paste on silver layer modified with nano-patterned structures for the first case. In the second case, vertically aligned carbonnanotubes were grown on the Au working electrode. The process of the nanotubes growing was tested to create homogenous and high density carbon nanotubes layer directly on the thick-film silver layer. Based on the characterization of electrodes, we used Au based for detection of nucleic acids. Moreover, we were able to estimated melting points of DNA. © 2009