Nanoneedle-Electrode Devices for In Vivo Recording of Extracellular Action Potentials

Area of Science:

• Neuroscience
• Bioengineering
• Materials Science

Background:

• Microscale needle electrodes enable high-resolution extracellular recording.
• Miniaturizing electrodes to the nanoscale reduces tissue damage but increases electrical impedance, degrading signal quality.

Purpose of the Study:

• To overcome the signal degradation caused by high impedance in nanoscale electrodes.
• To improve the amplitude gain and recording quality of nanoelectrodes for neuronal signals.

Main Methods:

• Fabrication of a 300 nm tip diameter, 200 μm long needle electrode.
• Integration of a source follower amplifier module with the nanoelectrode.
• Recording of local field potentials and action potentials in mouse cortex.

Main Results:

• Amplitude gain of the high-impedance electrode (>15 MΩ, 1 kHz) improved from 0.54 (-5.4 dB) to 0.89 (-1.0 dB) with the amplifier.
• Successful recording of both local field potentials (<300 Hz) and action potentials (>500 Hz) using the nanoelectrode with amplifier.
• Demonstrated contrast in recording capability compared to electrodes without amplification.

Conclusions:

• The proposed amplifier configuration effectively compensates for the high impedance of nanoscale electrodes.
• Miniaturized microelectrodes with this amplifier design facilitate low-invasive recording in submicron neural areas.
• This technology advances electrophysiological studies in tissues like dendrites and axons.