A Thin Film Transistor Backplane for Scalable Chronic Neural Interfaces

Abstract

Scaling neural interfaces to ever-higher channel counts has accelerated rapidly with advances in thin-film fabrication, lithography, and connectorization, enabling passive arrays to reach thousands of channels and chart credible pathways to much larger formats. Integrating active electronics directly at the sensing sites offers a complementary route to higher channel density by reducing the number of interconnects required to access large arrays. Here we introduce a monolithic flexible thin-film integrated circuit platform for active neural sensing, inspired by active-matrix display technology. The system integrates dual-gate amorphous indium gallium zinc oxide transistors on polyimide substrates to implement in-pixel transconductance amplification and row-column time-division multiplexing, improving scability for high-channel-count applications. Co-optimization of device architecture, contact engineering, and a hybrid ceramic-polymer thin-film encapsulation yields stable operation with projected lifetimes exceeding 38 years under accelerated aging. In acute and chronic in vivo rat studies, the platform exhibits negligible thermal burden, robust sensory-evoked recordings, and stable functionality over 30 days despite tissue encapsulation. These results establish display-inspired flexible thin-film electronics as a scalable building block for next-generation neural interfaces.