Brain-computer interfaces (BCIs) provide a direct connection to external devices and allow an exchange of information. They can help explore how the brain works with another dimension of electrophysiological information, and they show potential in clinical medicine, brain and neuroscience research, robot control, communications, daily healthcare, and entertainment.

Huang et al. described how flexible electronics can be applied for noninvasive BCIs.

“After years of research in the field, we deeply understand the value of flexible electrodes and believe this technique can provide a new strategy for more widespread use of next generation, noninvasive BCIs,” said author Sen Lin. “We believe our article will be of interest to researchers in flexible electronics, materials science, clinical medicine, and neuroscience.”

Invasive BCIs aim to detect and translate intercranial electrophysiological signals in vivo, but the necessary implantation can lead to trauma and biocompatibility issues. In contrast, using commercial, noninvasive BCIs involves assembling an electrode cap and injecting a conductive gel, then acquiring, amplifying, and analyzing electroencephalogram signals.

“In this case, the contact between the electrodes and the participant’s scalp becomes one of the most important factors affecting non-invasive BCI system performance,” said Lin.

The team discussed challenges and future directions for noninvasive BCIs, including the development of more flexible and reliable electrodes, the design of stable and low impedance skin-electrode channels, high-performance data analysis algorithms and real-time data control technology, and hybrid BCI technologies.

They are currently working on a new generation of semi-dry electrodes for long term electroencephalogram signal acquisition.

Source: “Flexible electrodes for non-invasive brain-computer interfaces: a perspective,” by Zhibao Huang, Zenan Zhou, Jiasheng Zeng, Sen Lin, and Hui Wu, APL Materials (2022). The article can be accessed at