Electrochemical Characterization of Implantable High Aspect Ratio Nanoparticle Platinum Electrodes for Neural Stimulations

Abstract

Two-dimensional (2D) and three-dimensional (3D) patternable conductive structures such as entire neural stimulation circuit are created by using metal nanoparticles and a nanopowder molding process. Fabricated structures retain a height-to-width ratio of up to 10:1. The described process is able to fuse the stimulating electrode, connection trace, and contact pad into one continuous, integrated structure where different sections can have different heights, widths, and shapes. The batch process is suitable for mass production, and the fabricated electrode is robust and very flexible. Additionally, the completed structure can be packed onto a biocompatible flexible substrate, such as poly-dimethylsiloxane, parylene, and polyimide as well as other temperature-sensitive or vacuum-sensitive materials at room temperature which make it more suitable for biomedical applications. Experimental data show that the electrodes and wires have about the same electrical resistivities as their bulk materials and desirable electrochemical properties, including low impedance. The nanoscale feature on the electrode surface enhanced the interface and contact quality between electrode and bio-substrate that led to better electrochemical performance.