Yuefeng Rui

Control of swimming in crucian carp: Stimulation of the brain using an implantable wire electrode

Control of locomotion in different kinds of animals, or so-called bio-robot, has been reported. Bio-robot is a technology based on the information communication between the nerve tissue and the computer. In this work, to study the locomotion control in carps brain, a Parylene-based wire microelectrode is fabricated for stimulation in midbrain. Compared with traditional microelectrodes, wire electrodes provide better bio-compatibility and good mechanical stability. The whole electrode was covered by Parylene C film, except the stimulation sites which are exposed by lift-off process, thus the interface impedance is significantly reduced. After the fabrication, crucian carps was anesthetized in MS-222 water solution and the cranium was partially removed to expose the midbrain. After all these steps, electrodes are tested to see if they are properly insulated. Then one electrode is implanted into the crucian carps midbrain by surgical procedure and the movement of the fish is observed by a video camera. The caudal fin movement of crucain carp is successfully induced by applying a single polar pulse train. This result proved the former theory that control region of carp is located in midbrain. On the other hand, the experiment shows great potential and promising future in the bio-robotic fish.

A Novel Transdermal Power Transfer Device for the Application of Implantable Microsystems

This paper presents a transdermal power transfer device for the application of implantable devices or systems. The device mainly consists of plug and socket. The power transfer process can be started after inserting the plug into the socket with an applied potential on the plug. In order to improve the maneuverability and reliability of device during power transfer process, the metal net with mesh structure were added as a part of the socket to serve as intermediate electrical connection layer. The socket was encapsulated by polydimethylsiloxane (PDMS) with good biocompatibility and flexibility. Two stainless steel hollow needles placed in the same plane acted as the insertion part of the needle plug, and Parylene C thin films were deposited on needles to serve as insulation layers. At last, the properties of the transdermal power transfer device were tested. The average contact resistance between needle and metal mesh was 0.454 Ω after 50 random insertions, which showed good electrical connection. After NiMH (nickel-metal hydride) batteries were recharged for 10 min with current up to 200 mA, the caused resistive heat was less than 0.6 °C, which also demonstrated the low charging temperature and was suitable for charging implantable devices.