Neural stimulation is a powerful tool to study brain physiology and an effective treatment for many neurological disorders. Conventional interfaces use electrodes implanted in the brain. As these are often invasive and have limited spatial targeting, they carry a potential risk of side-effects. Smaller neural devices may overcome these obstacles, and as such, the field of nanoscale and remotely powered neural stimulation devices is growing. This review will report on current untethered, injectable nanomaterial technologies intended for neural stimulation, with a focus on material-tissue interface engineering. We will review nanomaterials capable of wireless neural stimulation, and discuss their stimulation mechanisms. Taking cues from more established nanomaterial fields (e.g., cancer theranostics, drug delivery), we will then discuss methods to modify material interfaces with passive and bioactive coatings. We will discuss methods of delivery to a desired brain region, particularly in the context of how delivery and localization are affected by surface modification. We will also consider each of these aspects of nanoscale neurostimulators with a focus on their prospects for translation to clinical use.

神经刺激是研究大脑生理学的有力工具，也是许多神经系统疾病的有效治疗方法。传统的接口使用植入大脑的电极。由于这些通常是侵入性的并且空间定位有限，因此它们具有潜在的副作用风险。较小的神经设备可能会克服这些障碍，因此，纳米级和远程供电的神经刺激设备领域正在发展。本综述将报告当前用于神经刺激的无束缚、可注射纳米材料技术，重点是材料-组织界面工程。我们将回顾能够进行无线神经刺激的纳米材料，并讨论它们的刺激机制。从更成熟的纳米材料领域（例如，癌症治疗诊断学、药物递送）中获取线索，然后我们将讨论用被动和生物活性涂层修改材料界面的方法。我们将讨论传递到所需大脑区域的方法，特别是在传递和定位如何受表面修饰影响的背景下。我们还将考虑纳米级神经刺激器的各个方面，重点关注它们转化为临床应用的前景。