A chronic photocapacitor implant for minimally invasive neurostimulation with deep-red light

Implantable neuroelectronic devices are limited by a lack of reliable, safe, and minimally invasive methods to wirelessly modulate neural tissue. Here, we report the development of organic electrolytic photocapacitors to stimulate a peripheral nerve via the transduction of tissue-penetrating deep-red light into electrical signals. The photocapacitor relies on efficient charge generation by nanoscale organic semiconductors comprising non-toxic pigments, integrated on an ultrathin flexible cuff with ultralow volume (0.1 mm³). The device can be wirelessly operated from an external light source (via irradiation pulses of 50-1000 microseconds, at a wavelength of 638 or 660 nanometres), actuating the implanted device at a depth of approximately 10 millimetres below the skin’s surface. We demonstrate the device’s functionality <i>in vivo</i> on the sciatic nerve of a rat, where a microfabricated zip-tie mechanism stabilizes it into a fixed position and enabled its long-term implantation, allowing neurostimulation that can be sustained for over 100 days. Devices operated by organic electrolytic photocapacitors are a biocompatible approach to wireless neuromodulation and could be applicable to an array of clinical bioelectronics.可植入神经电子设备（implantable neuroelectronic devices）目前受限于缺乏可靠、安全且微创的无线调控神经组织的方法。本研究开发了有机电解光电电容器（organic electrolytic photocapacitors），通过将穿透组织的深红光转换为电信号来刺激外周神经。该光电电容器依赖由无毒颜料构成的纳米级有机半导体实现高效电荷生成，这些半导体被集成在体积超小（0.1立方毫米）的超薄柔性袖套上。该设备可通过外部光源实现无线操控：采用波长638或660纳米、时长50至1000微秒的辐照脉冲，可在皮肤表面下约10毫米深度处驱动植入式设备。我们在大鼠坐骨神经上验证了该设备的体内（in vivo）功能：采用微加工制成的扎带结构可将设备固定于目标位置，支持长期植入，实现了超过100天的持续神经刺激。基于有机电解光电电容器的设备是一种具备生物相容性的无线神经调控方案，可应用于一系列临床生物电子领域。