Abstract:
Degeneration of photoreceptors in the retina is a leading cause of blindness, but commonly leaves the retinal ganglion cells (RGCs) and/or bipolar cells extant. Consequently, these cells are an attractive target for the invasive electrical implants colloquially known as \"bionic eyes.\" However, after more than two decades of concerted effort, interfaces based on conventional electrical stimulation approaches have delivered limited efficacy, primarily due to the current spread in retinal tissue, which precludes high-acuity vision. The ideal prosthetic solution would be less invasive, provide single-cell resolution and an ability to differentiate between different cell types. Nanoparticle-mediated approaches can address some of these requirements, with particular attention being directed at light-sensitive nanoparticles that can be accessed via the intrinsic optics of the eye. Here we survey the available known nanoparticle-based optical transduction mechanisms that can be exploited for neuromodulation. We review the rapid progress in the field, together with outstanding challenges that must be addressed to translate these techniques to clinical practice. In particular, successful translation will likely require efficient delivery of nanoparticles to stable and precisely defined locations in the retinal tissues. Therefore, we also emphasize the current literature relating to the pharmacokinetics of nanoparticles in the eye. While considerable challenges remain to be overcome, progress to date shows great potential for nanoparticle-based interfaces to revolutionize the field of visual prostheses.
摘要:
视网膜中光感受器的退化是导致失明的主要原因,但通常留下视网膜神经节细胞(RGC)和/或双极细胞存在。因此,这些细胞是侵入性电植入物的一个有吸引力的目标,俗称“仿生眼”。\"然而,经过二十多年的共同努力,基于传统电刺激方法的接口提供了有限的功效,主要是由于视网膜组织中的电流扩散,这就排除了高视力。理想的假体解决方案是侵入性较小的,提供单细胞分辨率和区分不同细胞类型的能力。纳米粒子介导的方法可以解决这些要求中的一些,特别注意的是可以通过眼睛的固有光学器件获得的光敏纳米颗粒。在这里,我们调查了可用于神经调节的已知的基于纳米颗粒的光学转导机制。我们回顾了该领域的快速进展,以及将这些技术转化为临床实践必须解决的突出挑战。特别是,成功的翻译可能需要将纳米颗粒有效递送到视网膜组织中稳定且精确定义的位置。因此,我们还强调了与纳米颗粒在眼睛中的药代动力学有关的当前文献。虽然仍有相当大的挑战有待克服,迄今为止的进展显示了基于纳米粒子的接口彻底改变视觉假体领域的巨大潜力。