Plant-Based Material Gives Life to Soft Robots

Researchers have used a material derived from plants to build shape-shifting tiny robots that could one day be used to do non-invasive surgeries inside the human body.

Scientists at the University of Waterloo created the robots from an advanced hydrogel material composed of cellulose nanoparticles, a material derived from plants, including cotton. 

The ability to orient these nanoparticles allows the researchers to program the material to change its shape when exposed to external chemical stimulation, they said. Further, the researchers can modify the material through magnetism to allow soft robots created with it to move freely throughout the human body. 

All of this facilitates a more-holistic approach to the design, synthesis, fabrication, and manipulation of microrobots that can be used to conduct medical procedures, such as biopsy and cell and tissue transport, in a minimally invasive fashion, said Hamed Shahsavan, a professor in the Department of Chemical Engineering who led the research. 

The combination of capabilities and principles applied to the work combine a variety of scientific disciplines, including heat and mass transfer, fluid mechanics, reaction engineering, polymers, soft matter science, and biochemical systems, he said.

Related:Microrobots Eyed for Use Inside the Human Body

"In my research group, we are bridging the old and new," explained Shahsavan, who also is director of the Smart Materials for Advanced Robotic Technologies (SMART-Lab), in a post on Waterloo News. "We introduce emerging microrobots by leveraging traditional soft matter like hydrogels, liquid crystals, and colloids."

Tiny Robot Swimmers

The tiny soft robots developed using the hydrogel are a maximum of one centimeter (about 0.4 in.) long and are biocompatible and nontoxic, which makes them well-suited for biomedical applications. Scientists can direct the robots to move through confined and flooded environments, such as the human body, to deliver payloads such as cells or tissues to a target position.

In addition to its shape-changing and movement capabilities, the material also is self-healing, which adds to the versality of application it can have, the researchers noted. This means that they can cut the material and paste it back together without using glue or other adhesives to form different shapes for different procedures.

To test how the robot might move through the human body, the researchers successfully maneuvered it through a maze by controlling its movement through a magnetic field. They published the results of their research in a paper in the journal Nature Communications.

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Future plans for the next phase of research include scaling down the robot to submillimeter scales to further diversify its potential use for even more precise application, the researchers said.