Synthesis Of PANI Composite Material Coatings And Their Effect On Interface Properties Of Neural Microelectrode

Nervous system is a very complex system what plays an importantrole in human body function adjustment. For a long time, people have beentrying to research the mystery of the nervous system, understand themechanism of the nervous system and its structure, and to explore effectivemethod for the treatment of neurological diseases. Neural prosthesis，based on the bioelectricity, can be effectively connected with the nervoussystem, so as to realize the monitoring and recording of neural electricsignals, or the electrical stimulation of nerve tissue. It is of greatsignificance to reveal the structure and working mechanism of the nervoussystem, as well for the treatment of neurological diseases and neurologicalrehabilitation.Neural microelectrode, as the critical component connecting theinterface of nervous system and prosthesis devices, is very critical torealize the neural stimulation or neural signal records. So, the interface ofthe neural microelectrode-nerve cells plays a vital role in the process oflong-term neural prosthesis implanted. However, neural microelectrodealways shows high impedance due to its small surface area. In order to getthe appropriate charge density, high impedance electrodes would result in alarge applied electrode potential, lead to undesirable electrochemicalreactions that may be harmful to the tissue. Meanwhile, during thelong-term working process of the microelectrode implant, microelectrodewill cause encapsulation on the nerval electrode/tissue interface, whichwould increase interface impedance and reduce the charge transport abilitythat eventually lead to weak electrical signal, until final failure. Therefore, obtaining effective long-term electrical signal of neural microelectrodes isquite critical.In order to obtain a nerve electrode-nerve tissue interface withexcellent electrical performance, to get a low impedance interface, so as toensure good biocompatibility, good contact thereby realizing expectantfunction between records or stimulator electrode and nerve tissue, amodification scheme based on conductive polymer modified neuralmicroelectrode surface was proposed in this study. The work is mainly toqualitatively research the influence of polyaniline composite coatingsmodification on the electrical properties and electrochemical stability forelectrode, what offering insight and reference for the following surfacemodification scheme and preparation of new type neural electrode.In this work, different coatings with aniline monomer as rawmaterial and carbon nanotubes (CNTs), manganese dioxide (MnO2) asdopant, was modified on the Pt electrode surface. Through combiningdifferent materials with unique properties together on electrode, new nanocomposite coatings could be prepared, what can make electrode have moreexcellent electrochemical performance and stability. Atomic ForceMicroscopy (AFM), infrared spectroscopy (IR), electrochemicalimpedance spectroscopy (EIS) and Cyclic Voltammetry (CV) have beenused to characterize the electrode–electrolyte interface of the modifiedneural electrodes. The effect of the MWCNT and MnO2doping on PANIcoating has also been studied.Results show that the composite materials coatings with MWCNTand MnO2doping can effectively improve the surface morphology PANIcoating, increase the charge and capacitance of electrode, and reduce theimpedance as well, leading more excellent electrical properties andelectrochemical stability.