Modulus-tunable multifunctional hydrogel ink with nanofillers for 3D-Printed soft electronics.

Area of Science:

• Materials Science
• Biomedical Engineering
• Soft Robotics

Background:

• Mechanical mismatch between soft electronics and biological tissues hinders conformal interfacing.
• Existing soft hydrogels for bioelectronics have limitations in electrical and mechanical performance.

Purpose of the Study:

• To develop a 3D-printable, modulus-tunable hydrogel with enhanced functionalities for bioelectronic applications.
• To address the challenges of seamless integration and conformal contact of soft electronics with tissue surfaces.

Main Methods:

• Development of a cross-linked double network hydrogel structure.
• Incorporation of functional fillers like XLG or functionalized carbon nanotubes (fCNT) for tunable mechanics and conductivity.
• 3D printing utilizing rheological properties for customized bioelectronic designs.

Main Results:

• Achieved tunable mechanics (Young's modulus: 10-300 kPa) and electrical conductivity (~20 S/m).
• Demonstrated superior properties including stretchability (~1000% strain), self-healing (within 5 min), high toughness (400-731 kJ/m³), viscoelasticity, tissue conformability, and biocompatibility.
• Successfully fabricated ring-shaped strain sensors for wearable applications.

Conclusions:

• The developed hydrogel overcomes limitations of existing materials for soft bioelectronics.
• The tunable and printable nature of the hydrogel enables customized, high-performance wearable sensors.
• This material facilitates seamless integration of electronics with biological tissues for advanced monitoring.