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长期面临缺乏可靠、安全且微创的无线调控神经组织方法的困境。本研究报道了一种有机电解光电电容器（organic electrolytic photocapacitors），其可通过将穿透组织的深红光转换为电信号，实现外周神经刺激。该光电电容器依靠由无毒颜料构成的纳米级有机半导体实现高效电荷生成，这些半导体被集成于体积超小（0.1 mm³）的超薄柔性袖套之上。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，即可在皮肤表面下约10毫米深度处驱动该植入式器件。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将器件固定于目标位置，可实现长期植入，神经刺激效果可维持100天以上。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，可应用于众多临床生物电子学领域。