Impedance characterization of mems based all diamond neural probe

Microelectrodes are becoming an important tool for sensing of neuro-chemical and neuro-electrical signals for studying neural activities. Although a lot of work has been done for the development of microelectrodes made up of different materials, such as metal micro-wires, ceramic oxide, polymers, carbon fiber microelectrodes and silicon but these are still far from being satisfactory. An ideal material should have excellent biocompatibility, high signal-to-noise ratio and excellent electrochemical properties. The work of this paper focused on the development and impedance characterization of MEMS based All-Diamond neural probe, a new generation of probe with excellent properties such as wider potential window, low back ground current, very high and low electrical resistivities when doped and undoped respectively, mechanical flexibility and biocompatibility. A novel diamond probe with multiple microelectrodes has been presented with the characterization and test results of these developed probes for biomedical application. In this paper, we have characterized diamond probe for neural prosthetic applications. A test cell has been specially designed for In-Vitro testing of microelectrodes on the probe. Impedance, Capacitance and Resistivity characteristics were studied as a function of size of microelectrode, which were found to be 16.273 × 10³ ohm, 1.92 to 3.78 ¿F and 28.21 ohm that are in accordance with the theoratical electrochemical equations.