A freestanding submicron electrocorticography electrode array

Abstract

Electrocorticography electrode arrays (EEAs) are key brain-computer interfaces. To be freestanding, which lays the foundation of fabrication and implantation, EEAs need to maintain sufficient rigidity. However, to form seamless and damage-free contact on the cerebral cortex, EEAs should be super-flexible, raising a seemingly unsolvable dilemma. Here, inspired by dragonfly wings, we present a freestanding submicron EEA (fs-EEA) that combines rigidity and flexibility, which are typically mutually exclusive characteristics. A wing vein-like frame is introduced to enable the freestanding capability, while the wing membrane-like functional region of fs-EEA is reduced to 850-nm-thickness that boosts its softness. This fs-EEA ensures excellent cortical conformality and biocompatibility on male epileptic rat models, improves electrocorticographic amplitude and signal-to-noise ratio. Our vein-membrane hybrid structure strategy thus resolves the inherent contradiction of EEAs, and has the potential to support advances in brain science and related fields. Creating electrocorticography electrode arrays which are flexible enough for conformal contact but sufficiently rigid to be freestanding, is highly challenging. Here, inspired by dragonfly wings, the authors propose a vein-membrane hybrid structure strategy and develop a freestanding submicron EEA.