Advanced Science | Long-Term Stable Subdural Recordings Enabled by Fibrosis-Resistant Hydrogel-Integrated µECoG Arrays | Ting Wu Lab, Dong Qiu Lab
Abstract
The long-term performance of microscale subdural arrays is often compromised by adverse tissue responses, leading to increased electrochemical impedance and signal deterioration during chronic applications. Here, the study presents an adhesive hydrogel-integrated micro-electrocorticography (aGel-ﾵECoG) array that improves mechanical compatibility and adhesion to brain tissue, effectively mitigating tissue responses and enabling stable, high-performance electrical communication over days to months. The hydrogel consists of a hydrophilic polyvinyl alcohol and hydrophobic poly3-(trimethoxysilyl) propyl methacrylate heteronetwork, serving as a biological and mechanical bridging to enable seamless, anti-fibrotic, long-term integration with brain tissue. The aGel-ﾵECoG achieves robust tissue adhesion (25.2 ﾱ 3.8 kPa) with reversible and safe removal, enabling sutureless implantation. With an ultrathin 10-ﾵm ionic conductive hydrogel coating, the array exhibits high electrical fidelity, effectively preserving fine-grained sub-millimeter spatial resolution and maintaining unattenuated signal strength for functional cortical mapping. Compared to conventional ﾵECoG arrays, aGel-ﾵECoG exhibits a 20-fold reduction in acute-phase impedance increases, attributed to significantly reduced neuroinflammation and fibrotic tissue formation, as confirmed by histological analyses. Long-term recordings further reveal that aGel-ﾵECoG maintained 94.8% of the signal-to-noise ratio for steady-state visually evoked potentials over 16 weeks, whereas uncoated ﾵECoG arrays declined to 69.5%. These findings establish aGel-ﾵECoG as a durable and high-performance neural interface.
