Research On Fabrication Of Micro-Wire Electrode And Its Input-Output Properties

The researches goal of the Brain-Machine Interfaces(BMIs) design is to restore the injured motor and perception function for the people who suffer from various neurological disorders. As the cornerstone of the Brain-Machine Interface technologies, microelectrode is the connection bridges between nervous system and peripheral devices. And the researches and developments of microelectrodes Array consisted of multiple channels are of significant importance in the neural signal recording and nerve stimulation.Nowaday, Many popular multi-electrode arrays fabrication processes are complex, time-consuming and high-cost. These disadvantages hider the researchs of neuron signals. Therefore, developing a microelectrode array easy to fabrication remains very worthwhile. Allowing for many factors, such as amplitude attenuation, phase shift, noise and baseline drift which is existing in the transient neural signal collection, a microelectrode array fabrications scheme with rather low-cost is present in this thesis. In terms of the application of sensor, the performances evaluation and input-out properties of the fabricated microelectrode array is proceeded. The main research contents include:(1) Firstly, Typical commercial microelectrode array is introduced and compared systematacially, and the challenges, requirements, research direction and the problems existed in microelectrode array fabrications and applications are faced on were discussed.(2) Secondly, the mechanism of extracellular neural recording is analysed carefully. Then, the design and fabrication scheme of Micro-Wire Electrode Array are presented based on these mechanism analysis.(3) Thirdly, the mechanical, electrochemical performance, and the recording property in chronic implant experiments of the fabricated microelectrode array is evaluated. To improve the recording quality, some electrode surface modification is proceeded and tested.(4) In terms of the methodology of sensors, research on the input-output property of Nickel Alloy Micro-Wire Electrodes is processing. Based on the extracellular neural recording mechanism and factors which affect the input-output relationship of the biosensor, the equivalent circuit of extracellular recording including biopotential, thermal noise, static Nernst potential and amplifer is constructed. Based on the electrochemical impendence spectra, the ac property, noise property and dc baseline drift of micro-wire electrodes is researched.Experiment results show that micro-wire array fabricated by this low-cost micro-wire electrode fabrication scheme possesses acceptable performance and input-output property, and can meet the demands of intracortical neural signal recoding.