High-Density Flexible Electrode Arrays for Next-Generation Brain-Computer Interfaces

Abstract

Brain-computer interfaces (BCIs) require electrode arrays that simultaneously achieve high spatial resolution, mechanical compliance, and long-term biocompatibility. We fabricate ultra-flexible, high-density microelectrode arrays (HD-MEAs) with 1,024 channels on a 4 μm-thick parylene-C substrate using photolithography and lift-off metallization. The arrays conform to cortical surface curvature with <5% impedance increase after 10,000 bending cycles at 5 mm radius. In vivo recordings from macaque motor cortex demonstrate single-unit resolution across 256 simultaneously active channels, with signal-to-noise ratio (SNR) of 4.8 ± 0.6. A wireless headstage transmits neural data at 30 Mbps with 24-hour battery life, enabling untethered BCI operation for motor prosthesis control applications.