On-scalp printing of personalized electroencephalography e-tattoos

This paper presents a groundbreaking advancement in noninvasive brain-monitoring: on-scalp digital printing of custom-designed, temporary-tattoo-like sensors. This approach overcomes the limitations of traditional EEG systems by using material innovations and non-contact printing to fabricate self-drying, ultrathin e-tattoos compatible with hairy scalps, enabling comfortable, long-term, high-quality brain activity monitoring.

• On-scalp digital printing of custom-designed EEG e-tattoos.
• Fabrication of self-drying, ultrathin sensors compatible with hairy scalps.
• Enables comfortable, long-term, high-quality brain activity monitoring.
• Potential applications in BCIs for prosthetics, VR, and human-robot teaming.

Individual 3D head scans are used to design custom sensor layouts. A 5-axis microjet printing robot then prints the EEG e-tattoos directly on the scalp using biocompatible inks. The inks for electrodes and interconnects have different compositions to optimize for low skin impedance and high bulk conductivity.

The printed e-tattoos form conductive, stretchable, and breathable thin films that ensure high signal fidelity over extended periods. This technology paves the way for non-invasive, high-performance, and user-friendly brain monitoring, with broad potential applications beyond traditional EEG.