Light-Driven Undulatory Locomotion of a Liquid Crystal Gel Robot for Programmable 3D Navigation

Area of Science:

• Soft robotics
• Biomimetic engineering
• Materials science

Background:

• Existing soft robots lack continuous curvature, rapid actuation, and aqueous autonomy for medical applications.
• Aquatic organisms' undulatory swimming offers a model for efficient, untethered locomotion.

Purpose of the Study:

• To develop a novel soft robot capable of autonomous, reconfigurable underwater locomotion.
• To create a material system that integrates continuous curvature, rapid actuation, and aqueous autonomy.
• To demonstrate programmable navigation and cargo transport for minimally invasive medicine.

Main Methods:

• Fabrication of a leech-inspired robot from a single liquid-crystal gel (LCG) sheet.
• Encoding traveling-wave kinematics via the LCG's twist-nematic director field.
• Remote laser scanning for actuation, generating metachronal waves for propulsion and localized illumination for reorientation.

Main Results:

• The LCG robot achieved forward propulsion at 0.5 mm s^-1 in saline media.
• Programmable trajectories (upward, upper-left, upper-right) were demonstrated through localized head illumination.
• Integrated LCG constructs showed forward and rotating swimming modes, enabling cargo transport.
• Successful navigation through a 3D tunnel was achieved.

Conclusions:

• A novel LCG soft robot platform enables untethered, biomimetic underwater locomotion without on-board electronics.
• Molecular-level patterning translates optical commands into complex, reconfigurable movements.
• This technology offers a versatile platform for smart soft microrobots in fluidic environments, with potential for medical applications.