Flexible polyimide-based hybrid opto-electric neural interface with 16 channels of micro-LEDs and electrodes.

ABSTRACT: In this paper, a polyimide-based flexible device that integrates 16 micro-LEDs and 16 IrO _x -modified microelectrodes for synchronous photostimulation and neural signal recording is presented. The 4?×?4 micro-LEDs (dimensions of 220?×?270?×?50??m³, 700??m pitch) are fixed in the SU-8 fence structure on a polyimide substrate and connected to the leads via a wire-bonding method. The recording electrodes share a similar fabrication process on the polyimide with 16 microelectrode sites (200??m in diameter and 700??m in pitch) modified by iridium oxide (IrO _x ). These two subparts can be aligned with alignment holes and glued back-to-back by epoxy, which ensures that the light from the LEDs passes through the corresponding holes that are evenly distributed around the recording sites. The long-term electrical and optical stabilities of the device are verified using a soaking test for 3 months, and the thermal property is specifically studied with different duty cycles, voltages, and frequencies. Additionally, the electrochemical results prove the reliability of the IrO _x -modified microelectrodes after repeated pressing or friction. To evaluate the tradeoff between flexibility and strength, two microelectrode arrays with thicknesses of 5 and 10??m are evaluated through simulation and experiment. The proposed device can be a useful mapping optogenetics tool for neuroscience studies in small (rats and mice) and large animal subjects and ultimately in nonhuman primates.

SUBMITTER: Ji B 

PROVIDER: S-EPMC6220173 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature