Self-Healing Approach toward Catalytic Soft Robots

Abstract

Soft robotics is a rapidly evolving research field that focuses on developing robots with bioinspired actuation/sensing mechanisms and highly flexible soft materials, some of which are similar to those found in living organisms. The hydrogel has the characteristics of excellent biocompatibility, softness, and elasticity, which makes it an ideal candidate material for the preparation of soft robots. Here we utilized a self-healing approach to develop a catalytically driven soft robot, which was constructed by dynamic imine bonds between modular hydrogels. One of the modules was a hydrogel formed by dynamic aldimine cross-linking of chitosan and glutaraldehyde, and the other module was a hydrogel embedded with catalase. The soft hydrogel robot moved because of catalytic reactions between the robot and environment [hydrogen peroxide (H 2 O 2 ) fuel], giving rise to a fluidic release that supports propulsion, as inspired by the jet-propulsive mechanism in swimming dragonfly larvae. The speed of the soft robot can be mediated by adjusting the concentration of H 2 O 2 and enable/disable movement based on the folding and unfolding of enzymes. In addition, the hydrogel formed by replacing glutaraldehyde with dialdehyde-functionalized PEG 2000 had excellent elastic properties, and the soft robot based on PEG 2000 had a higher movement speed than that based on glutaraldehyde under the same H 2 O 2 concentration. Moreover, the addition of iron oxide nanoparticles can realize the magnetic guidance of the soft robot and the combination of different modules can realize different motion modes. The highly configurable self-healing catalytic soft robot holds great potential for a variety of interesting applications, including swimming robots, robot-assisted water treatment, and drug release.

Recent advances in electronic skins: material progress and applications

“…Using lithium bonds as depolymerization quenchers and dynamic mediators, Dang et al produced high-performance ionoelastomers by melting lipoic acid ( Dang et al, 2022 ). Self-healing hydrogels are also generated by forming dynamic aldehyde-amine crosslinks between chitosan and glutaraldehyde ( Wang et al, 2022d ).…”

Self-Healing Hydrogels: From Synthesis to Multiple Applications

“…By combining a hydrophilic hydrogel matrix with conductive materials (including conductive polymers, conductive metal particles, carbon nanotubes, etc. ), self-healing conductive hydrogels can be used in flexible sensors, , actuators, supercapacitors, , soft robots, − batteries, , etc. Self-healing hydrogels prepared by integrating non-cytotoxic and biocompatible natural polymer materials (chitosan, amino acids, sodium alginate, silk fibroin, etc.)…”

Fabrication and Applications of Magnetic Polymer Composites for Soft Robotics

“…The use of variable stiffness technologies, meticulous structural design, and programmable actuation has led to the development of new classes of materials and robotic systems that facilitate more natural interactions between robots and people [14]. Although research has concentrated on developing structures with less stiff components [15][16][17], there are still downsides to using only soft materials. When it comes to supporting their weight, smaller organisms in nature might be softer, while larger species need a skeleton [18].…”