Flexible Dual-Sided Polymer Microelectrode Array for Neurophysiological Recordings from an Insect Brain

Despite advances in modern microelectrode technologies, designing high-density flexible microelectrode arrays (MEAs) for small insect brains remains challenging, especially when aiming for dense microelectrode configurations on flexible substrates in restricted areas (e.g., 250×100 μm
²
). To overcome these challenges, we developed a novel dual-sided design that doubles the channel count and density of MEAs within the same spatial footprint in comparison with the single-sided counterparts. A unique folding-annealing method is introduced to craft Parylene-based flexible dual-sided density MEAs. These MEAs, with overall dimensions of 20 μm in thickness and 120-230 μm in width, are specifically tailored for the locust antenna lobe, which is the central odor processing circuitry in insects. The efficacy of the dual-sided MEA for neurophysiological sensing of odors was validated in vivo using a neural circuitry (antennal lobe) of the locust brain.