Material considerations for optical interfacing to the nervous system

Optical neural interfaces offer several advantages over electrophysiological methods in both clinical and experimental applications. Optical stimulation techniques exhibit high spatial selectivity, do not create electrical artifacts, and allow for stimulation of specific neuronal populations. Calcium- and voltage-sensitive dyes can probe neuronal and astrocytic signaling at both single cell and network scales, and miniature optical sensors can measure a variety of physiological signals in situ . However, optical neural interfaces must be robust, safe, and effective over long periods of time in order to be acceptable for use in human patients. In this article, we draw the attention of the materials science community to the need for a new generation of materials that have the necessary optical performance and, at the same time, conform to the constraints placed on implanted devices in terms of size, relevant mechanical properties, and biocompatibility, providing some examples of recent advancements in the field.