Floating 5-μm-Diameter Needle for Low Invasive Chronic Recording

Here we propose low invasive <;5-μm-diameter needle-electrode and the surgical procedure for chronic neuronal recording. The needle-electrode assembled on a 1 × 1 mm² device substrate is packaged with a flexible wire, as a `floating electrode' on the brain tissue. The needle-electrode, which was placed on a mouse's cortex, enabled the recording of neuronal activities in vivo. In addition, we confirmed that the proposed floating electrode reduced the tissue damage in the device implantation in a mouse for 7 days, compared to the other same diameter needle-electrode which substrate was attached to the cranium.