Implantable electrode array with platinum black coating for brain stimulation in fish

Abstract

Electrical stimulation of certain part of the neural tissue could evoke specific functional response. The interface plays an important role in stimulation process. Tungsten wire electrodes have long been used as an ideal interface for neural signal recording and stimulation. In this work, an electrode array with good electrochemical property and biocompatibility was successfully fabricated in a novel and convenient way. A PDMS electrode holder was made to fix the electrodes with certain distance. To achieve a better stimulation effect, a platinum black coating was electroplated, and the electrochemical properties of the electrode were tested. Tests results of the impedance and charge injection capacity showed great improvement in electrochemical property. To test the durability of the platinum black coating, the electrode was dealt with ultrasound vibration for 10 min and then re-tested for charge storage capacity lost. The array was then implanted into the midbrain of crucian carp by a surgical procedure. A stimulation pulse was applied in order to elicit a change in locomotion. By stimulating the midbrain part of the fish brain, both side turning movements were observed. Also, this work provides the fundamental experiment for the development of bio-robotic fish.