Enhanced Response of ZnO Nanorod-Based Flexible MEAs for Recording Ischemia-Induced Neural Activity in Acute Brain Slices

Brain ischemia is a serious condition caused by reduced cerebral blood flow, causing disruption of ion gradients in brain tissue. This ionic imbalance induces spreading depolarization—waves of neuronal and glial depolarization propagating through the gray matter. Microelectrode arrays (MEAs) enable real-time monitoring of these dynamics in vivo and in vitro, but their sensitivity and signal quality is critical for detecting extracellular brain activity. This study investigates the response of flexible MEA based on gold-coated Zinc Oxide nanorods (ZnO NRs) - called nano-fMEA, for monitoring neural activity under pathological conditions. Nano-fMEA electromechanical properties are shown and discussed to highlight the superior performance of this platform. Conventional MEAs and nano-fMEAs are evaluated on acute mouse brain slices in two ischemic models: oxygen-glucose deprivation (OGD) and hyperkalemia. The findings reveal that the nano-fMEA significantly improves event detection rates and captures subtle fluctuations in neural activity compared to conventional rigid MEAs. This enhanced sensitivity is attributed to the optimized electrode-tissue interface, which reduces impedance and improves charge transfer. The results indicate that the nano-fMEA is particularly effective in detecting weak or transient signals, making it a valuable tool for studying neural dynamics during metabolic stress. Overall, the research underscores the promise of ZnO NRs in advancing electrophysiological tools for neuroscience applications.