Transparent implantable devices have received significant attention in neuroscience and biomedical engineering by combining neural recording and optical modalities. Opaque, metal‐based electrode arrays for electrophysiology block optical imaging and cause photoelectric artifacts, making them difficult to integrate with optogenetics. Here, a photoelectric artifact‐free, highly conductive, and transparent poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) electrode array is introduced as promising neural implants. The technology which is developed in this work provides transparent neural interfaces through low‐cost, ultra‐facile method compared with other transparent materials being applied to implantable tools. The device exhibits superior optical, mechanical, and electrical characteristics to other studies, thanks to a simple ethylene glycol immersing process. The device performance is highlighted by comparing its light stimulation efficiency and photoelectric artifact extent with conventional thin gold electrodes both in vitro and in vivo. This platform can assemble transparent neural interfaces much more efficiently than any other material candidates and thus has many potential applications.

Challenges in the understanding of three-dimensional (3D) brain networks by simultaneously recording both surface and intracortical areas of brain signals remain due to the difficulties of constructing mechanical design and spatial limitations of the implanted sites. Here, we present a foldable and flexible 3D neural prosthetic that facilitates the 3D mapping of complex neural circuits with high spatiotemporal dynamics from the intracortical to cortical region. This device is the tool to map the 3D neural transmission through sophisticatedly designed four flexible penetrating shanks and surface electrode arrays in one integrated system. We demonstrate the potential possibilities of identifying correlations of neural activities from the intracortical area to cortical regions through continuous monitoring of electrophysiological signals. We also exploited the structural properties of the device to record synchronized signals of single spikes evoked by unidirectional total whisker stimulation. This platform offers opportunities to clarify unpredictable 3D neural pathways and provides a next-generation neural interface.

Figure 1. Schematic illustration of various bioelectronic devices based on 1D nanomaterials including nanowire, nanotube, and nanofiber. a) Nanowire, nanotube, and nanofiber are the representative 1D nanomaterials. b) Cellular scale bioelectronics based on 1D nanomaterials for cell signal recording and stimulation. Nanowire array to monitor signal of cell: Reproduced with permission. [93] Copyright 2017, American Chemical Society. 3D nanowire FET scaffold to record and stimulate cultured cells: Reproduced with permission. [102] Copyright 2016, Springer Nature. c) Tissue scale bioelectronics based on 1D nanomaterials for signal recording and therapeutic functions. Nanofiber-based cuff electrode for neuroprosthetics: Reproduced with permission. [116]