In vivo neuronal recordings using three-dimensional microneedle-electrode assembled on flexible substrate

Further requirements for microelectrode devices used in in vivo neuronal recordings include i) the fine needle geometry, ii) miniaturization of the device substrate, and iii) the device flexibility. This paper reports a <; 10-μm-diameter three-dimensional (3D) needle-electrode assembled on a 10-μm-thick 1×2 mm
²
flexible film. Herein, we developed a fabrication process, in which a vapor-liquid-solid (VLS) grown vertical Si-microneedle was assembled on a Si film which was released from the Si substrate with a flexible film of parylene. The fabricated device shows the neuronal recording capability, as demonstrated in the in vivo recording of action potentials (spikes) from a mouse's cortex.