fig2

Figure 2. Flexible devices for direct electrical nerve stimulation. (A) Schematic diagram of the polyimide-based neural probe, showing the flexibility of the probe, which can still move freely after being implanted in the mouse brain region^[22]. Reprinted with permission. Copyright 2012, IOP Publishing; (B) Schematic diagram of the ultra-thin flexible polyimide neural probe. After successfully penetrating, the brain maltose dissolves, and the rigid probe becomes a flexible neural probe^[25]. Reprinted with permission. Copyright 2014, IOP Publishing; (C) Scanning electron microscope imaging of flexible CNT electrode array mounted on PCB holder^[28]. Reprinted with permission. Copyright 2014, Springer Nature; (D) Dual-channel CNT fiber microelectrode^[29]. Reprinted with permission. Copyright 2015, American Chemical Society; (E) CNT yarns with a diameter of 10 μm, wound on tungsten for implantation in a nerve, and the distance between the two CNT yarns after implantation is about 2 mm^[30]. Reprinted with permission. Copyright 2017, Springer Nature; (F) Photograph of the implantable ICH^[34]. Reprinted with permission. Copyright 2023, Soft Science; (G) Schematic diagram of the metal electrode coated with the conductive polymer hydrogel (PEDOT:PSS), which can endow the electrode with superior biocompatibility and electrical and mechanical properties^[35]. Reprinted with permission. Copyright 2023, Wiley-VCH GmbH; (H) Flexible SiC/SiO₂ bioelectronic system for stimulating the sciatic nerve^[36]. Reprinted with permission. Copyright 2022, PANS. CNT: Carbon nanotubes; ICH: injectable conductive hydrogel; PCB: printed circuit board; PEDOT:PSS: poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate).