Bilayer hydrogel actuators with tight interfacial adhesion fully constructed from natural polysaccharides

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Smart hydrogel actuators are crucial for advanced biomedical applications due to their biocompatibility and biodegradability.
• Existing hydrogels often lack the mechanical robustness and precise shape-morphing capabilities required for complex biological tasks.

Purpose of the Study:

• To engineer novel bilayer bio-hydrogel actuators inspired by plant structures.
• To achieve robust adhesion and pH-triggered actuation for versatile shape transformations.
• To explore the potential of these hydrogels in biomedical and biomimetic applications.

Main Methods:

• Constructed bilayer hydrogels using chitosan and cellulose/carboxymethylcellulose (CMC) in an alkali/urea system with epichlorohydrin (ECH) crosslinker.
• Utilized electrostatic attraction and chemical crosslinking for strong interlayer adhesion.
• Investigated pH-triggered swelling/deswelling behavior for actuation and shape morphing.

Main Results:

• Developed bilayer hydrogels with excellent mechanical properties and rapid, reversible self-rolling deformation.
• Achieved diverse shape transformations (rings, tubules, flower-like, helix, bamboo, wave) by controlling geometry.
• Demonstrated hydrogel functionality as soft grippers, smart encapsulators, and bioinspired lenses.

Conclusions:

• The developed bio-hydrogel actuators offer a promising platform for advanced biomedical devices and biomimetic machines.
• The pH-responsive, shape-morphing capabilities highlight their potential in soft robotics and drug delivery systems.
• The bio-inspired design and tunable properties pave the way for next-generation smart biomaterials.