Robust Neural Interfaces Enabled by Non‐Deformable Adhesive Hydrogel Patch for Stable Chronic ECoG Recording

Abstract Micro‐electrocorticography (micro‐ECoG) with superior temporal and spatial resolution plays a critical role in precise brain mapping and decoding of brain activities. However, due to inevitable device‐brain displacement in cerebrospinal fluid, the weak physical attachment of micro‐ECoG devices on the cortical arachnoid tissue cannot ensure a stable neural interface to achieve durable and reliable ECoG recording over time. Herein, a robust neural interface is explored using a bio‐adhesive hydrogel patch for stable chronic ECoG recording. To overcome the challenges in dimensional instability of hydrogels, such as swelling and shrinkage, which would impede the safe integration of micro‐ECoG devices on fragile cortical surface, a non‐deformable hydrogel patch is developed through rational design with balanced molecular chain topology to resist dimensional changes. The multifunctional non‐deformable hydrogel demonstrates desired merits including rapid wet‐tissue adhesion (within 30 s), anti‐postoperative adhesion, excellent biocompatibility, ease of surgical handling, and scalability for large‐scale production. Compared to conventional swelling or contractile hydrogels, the non‐deformable hydrogel patch on a cortical surface can effectively inhibit fibrous capsule formation and glial cell recruitment. Furthermore, long‐term recordings from micro‐ECoG devices integrated with non‐deformable hydrogel patches demonstrate excellent stability and high‐fidelity electrophysiological signals, making it a promising advancement for chronic, durable, and reliable neural interface applications.