Breathable, Adhesive, and Biomimetic Skin-Like Super Tattoo

Area of Science:

• Materials Science
• Biomedical Engineering
• Wearable Electronics

Background:

• Electronic tattoos require substrates that mimic skin's mechanical properties, adhesion, and breathability for effective bio-signal acquisition.
• Current tattoo substrates face challenges in achieving a balance of these critical characteristics, limiting their application in healthcare and human-machine interfaces.

Purpose of the Study:

• To design and fabricate an ultra-thin, skin-mimetic tattoo substrate with enhanced adhesion, breathability, and mechanical properties.
• To evaluate the substrate's potential as a universal platform for electronic tattoos capable of imperceptible bio-signal monitoring.

Main Methods:

• Fabrication of an ultra-thin film (≈2 µm) designed to replicate the mechanical and adhesive properties of human skin.
• Characterization of the substrate's strain-adaptive stiffening, tear energy, toughness, adhesion, ionic conductivity, and permeability.
• Integration of conductive electrodes onto the substrate and assessment of their performance in monitoring electromyography (EMG) signals.

Main Results:

• The developed 'super tattoo' substrate exhibits skin-like strain-adaptive stiffening, high tear energy (5.4 kJ·m⁻²), and toughness (1.3 MJ·m⁻³).
• The substrate demonstrates superior adhesion, ionic conductivity, and permeability compared to natural skin.
• Electrodes processed on the substrate showed stable, low contact impedance and accurately monitored weak EMG signals during swallowing.

Conclusions:

• The novel super tattoo substrate offers an ideal platform for electronic tattoos due to its skin-mimetic and superior material properties.
• The substrate enables imperceptible and accurate monitoring of bio-signals, showing promise for applications in healthcare, particularly for dysphagia rehabilitation training.