Researchers at the University of Waterloo in Canada have developed plant-based microrobots that are intended to pave the way for medical robots that can enter the body and perform tasks, such as obtaining a biopsy or performing a surgical procedure. The robots consist of a hydrogel material that is biocompatible and the composite contains cellulose nanoparticles derived from plants. The researchers can tune the orientation of the cellulose nanoparticles such that they respond in predictable ways when exposed to certain chemical cues such as changes in pH. This includes changing the shape of the tiny robots so that they are better adapted to their immediate environment. Incorporating magnetic elements allows the robots to be moved using external magnetic fields and deliver cargoes, such as drugs, to different areas of the body.
Researchers are working hard to expand the role of larger soft robots in the field of medicine. These devices are particularly good at interacting with soft tissues because of their mechanical properties, and therefore have enormous potential as surgical robots or those that provide assistance for daily living. However, soft microrobotics is a relatively underexplored area, but tiny soft structures that can travel throughout the body without causing significant damage to soft tissues intuitively seems like a winning idea.
This latest advancement comes in the form of a plant-based soft material made using cellulose nanoparticles that is non-toxic and biocompatible. The soft material also has self-healing properties, meaning that it can be cut and stuck back together without any adhesive, potentially allowing clinicians to easily customize it for different applications depending on the required size and shape.
The robots are a maximum of one centimeter in length and can be moved by incorporating magnetic components that can then be influenced using magnetic fields applied outside the body. In this manner, the robots can deliver drugs or other therapeutics to precise areas of the body. “In my research group, we are bridging the old and new,” said Hamed Shahsavan, a researcher involved in the project. “We introduce emerging microrobots by leveraging traditional soft matter like hydrogels, liquid crystals, and colloids.”
In tests so far, the researchers have been able to manipulate the robots to travel through a maze, suggesting that they may be able to navigate our tortuous vasculature.
See a Waterloo Engineering video of this process below:
Study in Nature Communications: Programmable nanocomposites of cellulose nanocrystals and zwitterionic hydrogels for soft robotics