Donut-shaped micro-robot moves autonomously in slime under light control
A micro-robot made of special elastomer and excited by laser light can move in viscous liquids. This is made possible by its donut shape.
(Image: Hao Zeng / Tampere University)
Scientists at Tampere University in Finland and Anhui Jianzhu University in China have developed a donut-shaped micro-robot made of a special elastomer that can move in viscous liquids when stimulated by laser light. The researchers see potential applications for the robot in medicine and environmental monitoring.
Microorganisms can move easily in viscous environments. To this end, they have developed various locomotion mechanisms, such as corkscrew movements, wave-like movements with cilia or whip-like strokes. Inspired by nature, the researchers at Tampere University have considered how a micro-robot can overcome viscous forces. They have presented the results of their research in the study "Light-steerable locomotion using zero-elastic-energy modes", which has been published in Nature Materials.
Rotary motion using laser light
The central element of the robot is a liquid crystalline material that reacts to laser light. When heated, the elastomer independently performs a rotational movement due to a zero-elastic-energy mode (ZEEM), which is created by an interplay of static and dynamic forces.
The researchers used a donut shape for the robot. The physicist Edward Purcell had already demonstrated in 1977 that a toroidal shape can improve the navigation of microscopic organisms in environments in which viscous forces prevail and inertial forces are negligible. This is known as the Stokes regime. However, no such toroidal swimmer has yet been developed.
"Our innovation enables three-dimensional free swimming in the Stokes regime and opens up new possibilities for the exploration of confined spaces, such as microfluidic environments. In addition, these toroidal robots can switch between rolling and self-propelled modes to adapt to their environment," says Ziuan Deng, PhD student and first author of the study.
The scientists are convinced that their research work can contribute to the development of micro-robots that can move in complex environments. The researchers envisage areas of application such as medical applications for transporting drugs in the human body or for monitoring the environment.
(olb)