Fabrication and application of conductive biosurfaces.
Date of Issue2013
School of Chemical and Biomedical Engineering
Advanced Materials Research Centre
Neurons communicate via secretion of neurotransmitters which trigger electrical responses to modulate neuronal firings and consequently, animal behaviors. Therefore, monitoring these signals in neurons of ambulatory subjects is crucial to investigate the neural basis of behavior, a fundamental goal in neuroscience. In addition, even as common diseases afflicting the elderly across the globe, there is no cure for such neurological disorders. Neural electrode, designed and used to achieve recording of neural signals and stimulating neurons in the central and peripheral nervous system has attracted considerable interest as a potential approach for such neurological disorders. The challenges for researchers in this field are, however, to obtain stable neural signals for extended periods of time, which is often hindered by physiological environment, high interfacial impedance, and foreign body response. The goal of my resersach in this thesis is, therefore, to develop neural electrodes that facilitate electrical signal recording with minimized cellular response. In our research, we had mainly focused on the surface modification of neural electrodes with nanostructured coatings consisting of conductive polymers and/or carbon nanotubes (CNTs) with the aim to overcome the existing challenges and explore possible solutions to improve the electrode performance, e.g. lowering the interfacial impedance, enhancing the charge transfer capability, extending the electrode life time, and improving the cell-electrode integration. Several electrically conductive and cellular compatible nanostructured coatings consisting of conductive polymers and/or CNTs had been developed, including but not restricted to porous multilayered polypyrrole (PPy)-coated multiwalled carbon nanotube (MWCNT) films, highly porous and fibrillary-textured nanostructured poly(3,4-ethylenedioxythiophene) (PEDOT) films, and vertically aligned PEDOT nanotube arrays. When applying these nanostructures to microelectrodes, significantly lower interfacial impedance, larger charge storage capacity, improved electrochemical stability, and better cell-electrode integration have been observed. We believe that these nanoengineered materials would be great candidates to interface neural tissues and could contribute to the development of neural engineering.