Foldable 3D opto-electro array for optogenetic neuromodulation and physiology recording.

This paper presents a thin-film, three-dimensional (3D) opto-electro array featuring four addressable microscale light-emitting diodes (LEDs) for surface cortex illumination and nine penetrating electrodes for simultaneous recording of light-evoked neural activities. Inspired by the origami concept, we have developed a meticulously designed "bridge+trench" structure that facilitates the transformation of the array from 2D to 3D while preventing damage to the thin film metal. Prior to device transformation, the shape and dimensions of the 2D array can be customized, enhancing its versatility for various applications. In addition, the arched base offers strong mechanical support to facilitate the direct insertion of the probe into tissue without any mechanical reinforcement. The array was encapsulated using polyimide and epoxy to ensure mechanical flexibility and biocompatibility of the device. The efficacy of the device was evaluated through comprehensive in vitro and in vivo characterization.