On-scalp digital printing of custom-designed, temporary-tattoo-like sensors marks a significant advancement in non-invasive brain monitoring. Unlike traditional EEG systems, which require time-consuming setup, conductive gels, and cumbersome cables, this approach leverages material innovations and on-body digital printing to create ultrathin, self-drying, and skin-conformal e-tattoos compatible with hairy scalps.

Using 3D head scans, custom sensor designs, and a 5-axis microjet printing robot, these sensors offer precise placement, high signal fidelity, and long-term comfort. Specialized inks ensure low skin impedance and high conductivity, forming stretchable, breathable films after drying.

This technology not only enhances neuroscience and clinical diagnostics but also accelerates brain-computer interface (BCI) development for applications like prosthetics, virtual reality, and human-robot interaction. Additionally, it opens new possibilities for large-area, on-body digital manufacturing of functional e-tattoos for various regions beyond the scalp.