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 in vivo 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.

可植入式神经电子器件目前面临的核心局限在于，缺乏可靠、安全且微创的无线神经组织调控方案。本研究报道了一种有机电解光电电容器（organic electrolytic photocapacitors）的开发方案，该器件可通过将穿透组织的深红光转换为电信号，实现对外周神经的刺激。该光电电容器依托由无毒色素构成的纳米级有机半导体实现高效电荷生成，集成于体积超小（0.1 mm³）的超薄柔性神经袖套之上。该器件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器件。我们在大鼠坐骨神经上开展了体内功能验证：采用微加工制成的扎带结构可将器件固定于目标位置，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器件是一种具备生物相容性的无线神经调控方案，有望应用于各类临床生物电子领域。