Enzymatic Crosslinked Silk Fibroin Hydrogel for Biodegradable Electronic Skin and Pulse Waveform Measurements

Area of Science:

• Materials Science
• Biomaterials Engineering
• Wearable Electronics

Background:

• Development of portable, controllable, and eco-friendly electronic skin (e-skin) is a significant challenge.
• Existing e-skin technologies often lack biocompatibility, biodegradability, or ease of use.

Purpose of the Study:

• To design and fabricate a biocompatible and biodegradable hydrogel-based e-skin for spatial pressure distribution sensing.
• To utilize silk fibroin (SF) as a hydrogel skeleton for enhanced mechanical sensitivity and create a conductive hybrid film electrode.

Main Methods:

• Fabrication of a silk fibroin (SF) hydrogel with enzymatic crosslinking in weakly acidic media.
• Preparation of a conductive SF/polyvinyl alcohol (PVA) hybrid film electrode via graphite deposition.
• Assembly of an 8x8 pixel SF-based e-skin array.

Main Results:

• The SF sensing unit exhibited high strain sensitivity (4.78), rapid response (<0.1 s), and excellent cycling stability (≥10,000 cycles).
• The fabricated SF-based e-skin demonstrated high biocompatibility and biodegradability.
• The 8x8 pixel e-skin array successfully performed 3D signal transmission, tracking pulse pressure, finger joint movement, and vocal cord vibrations.

Conclusions:

• A novel silk fibroin hydrogel-based electronic skin offers a promising platform for advanced sensory applications.
• The developed e-skin meets desirable criteria for portability, controllability, and environmental friendliness.
• This research lays the groundwork for next-generation electronic devices utilizing biomaterial-based e-skin.