Self-Closed Parylene Cuff Electrode for Peripheral Nerve Recording

Abstract

We have designed, fabricated, and characterized a self-closed parylene cuff electrode for peripheral nerve recording, whose curliness and closeness is realized by the difference in self-stress of different parylene layers due to the heat treatments. Compared with the conventional cuff electrodes, the self-closed structure without any additional mechanical locking structure minimizes the mechanical structure of the cuff electrode. Moreover, the self-closed structure made of thin and flexible parylene film minimizes mechanical damage to the nerve and the surrounding tissues. The zero insertion force interface facilitates the connection of 16 channels with external circuits through the integrated parylene bonding pads. To reduce the impedance and increase the charge storage capacity of the electrode, the electrodeposited iridium oxide film is electrodeposited on the electrode sites. Using the fabricated self-closed parylene cuff electrode, acute neural recoding of 16 channels was performed on the rat sciatic nerve to verify the capability of recording the neural activities. The present self-closed parylene cuff electrode is promising to be used as an neural interface for peripheral nerve recording.[ 2014-0100]Index Terms-Cuff electrode, self-closed, MEMS, self-stress, electrodeposited iridium oxide film (EIROF), neural interface.

Micromachining of Parylene C for bioMEMS

“…b) . Thermal forming of Parylene free films has also been demonstrated by annealing multi‐layer Parylene devices with varying thickness or differing Parylene variants (Parylene C and N layers) to create residual stress differences to form self‐curling films . Metal molds have also been used to thermally shape Parylene planar films into curved (Fig.…”

“…By sandwiching multiple layers of Parylene and metal traces, high‐density neural probes with 256 electrodes on a single shank have been produced . Parylene‐based cuff electrodes for recording from nerve fibers in the peripheral nervous system have also been developed that utilize thermal curling or built in ratcheting structures to create conformal wrapping around fibers for improved signals. Planar Parylene spinal cord stimulators have also been fabricated and chronic performance demonstrated in rat animal models…”

Progress in Research of Flexible MEMS Microelectrodes for Neural Interface

“…Xiaoyang Kang and Jingquan Liu et al of Shanghai Jiao Tong University also developed iridium oxide (IrOx) as an important electrochemical modification material for neural interface, which exhibited considerable value in neural stimulation and recording applications [67][68][69][70][71]. There were various kinds of preparation methods for IrOx, including: sputtering iridium oxide film (SIROF), activated iridium oxide film (AIROF) and electrodeposited iridium oxide film (EIROF), as shown in Figure 8a-c. For SIROF, the iridium atom combined with oxygen atom under vacuum condition to form IrOx.…”

Techniques and Considerations in the Microfabrication of Parylene C Microelectromechanical Systems

“…Microfluidic channels were integrated into Parylene neural probes to inject drugs [ 43 , 44 , 45 ]. Parylene-based cuff electrodes, which record neural activity within peripheral nerves, were also developed [ 46 , 47 , 48 ]. Parylene spinal cord stimulators have also been realized with high-density electrode sites [ 49 , 50 ].…”