Short communicationCNT-Au nanocomposite deposition on gold microelectrodes for improved neural recordings

- The hierarchical structure was developed using CANs to enhance the electrochemical surface area (ESA) of MEA electrode.
- The MEA impedance modified with CANs was reduced by approximately 99.3% compared with pure gold microelectrode, and the impedance magnitude was around 50 kΩ.
- Comparing the “impedance with respect to surface area (=ІZІat1kHz × surface area)” with previous studies, the value of our results is ranked third in the 11 previous studies.
- The recording performance (peak amplitude: 340-470 μVpp, noise level: 3.5-5.3 μVrms) is outstanding compared to previous reports (peak amplitude: 100-500 μVpp, noise level: 3-5 μVrms).

Microelectrode arrays (MEAs) are widely used in neural recordings of cultured neurons and neural tissues. The impedance of neural electrodes is an important factor because it determines the signal-to-noise ratio (SNR) of the recorded neural signals. Here, we developed a modified technique using CNT-Au nanocomposites (CANs) for MEAs. The impedance of CAN-modified microelectrodes was greatly decreased versus pure gold microelectrodes due to their large electrochemical surface area (ESA). Importantly, when compared in terms of “impedance with respect to surface area” with previous reports, the value was 8.8 MΩμm2, which is outstanding. Cultured neurons showed good viability and the SNR (average SNR = 92) of recorded neural signals with CAN-modified microelectrodes was sufficiently high compared with previous studies. This modified technique will provide a significant advancement in MEA chips and could also be applied to various neural electrodes, such as Si electrodes, multiple site electrodes, and tetrodes.