Subdural neural interfaces for long-term electrical recording, optical microscopy and magnetic resonance imaging

Though commonly used, metal electrodes are incompatible with brain tissues, often leading to injury and failure to achieve long-term implantation. Here we report a subdural neural interface of hydrogel functioning as an ionic conductor, and elastomer as a dielectric. We demonstrate that it incurs a far less glial reaction and less cerebrovascular destruction than a metal electrode. Using a cat model, the hydrogel electrode was able to record electrical signals comparably in quality to a metal electrode. The hydrogel-elastomer neural interface also readily facilitated multimodal functions. Both the hydrogel and elastomer are transparent, enabling in vivo optical microscopy. For imaging, cerebral vessels and calcium signals were imaged using two-photon microscopy. The new electrode is compatible with magnetic resonance imaging and does not cause artifact images. Such a new multimodal neural interface could represent immediate opportunity for use in broad areas of application in neuroscience research and clinical neurology.

Automated summary

A new neural interface material composed of hydrogel and elastomer has been developed, which shows comparable electrical signal recording quality to metal electrodes with less glial reaction and cerebrovascular destruction. This material also allows for multimodal functions and is compatible with in vivo optical microscopy and magnetic resonance imaging.