Tuesday, November 28, 2023

Inchworm-inspired gelbots move without batteries

Researchers at Johns Hopkins University have developed a new gelatinous robot that crawls, powered by nothing more than temperature change and clever design. The inchworm-inspired robot brings “a kind of intelligence” to the field of soft robotics.

These worm-like robots are designed to crawl through the body and target the source of illness, delivering a high dose of medication and possibly replacing pills or intravenous injections that can cause life-threatening side effects.

Robots are typically comprised almost exclusively of hard materials like metals and plastics. This has been a fundamental obstacle in the push to create robots ideal for human biomedical advancements. Water-based gels are one of the most promising materials in the field of soft robotics. Previous research has demonstrated that gels that swell or shrink in response to temperature can be used to create smart structures.

Now, for the first time, the Johns Hopkins team has shown how the swelling and shrinking of this gelatinous material can be strategically manipulated to move robots forward and backward on flat surfaces. They can also be encouraged to crawl in certain directions with an undulating, wave-like motion.

The new gelatinous robot is 3D-printed and made out of gelatine. The slug is powered solely by manipulating temperature fluctuations between 30 and 60 degrees Celsius, which can either swell or shrink its gel body. According to the researchers, the gelbots would be easy to mass produce.

“It seems very simplistic, but this is an object moving without batteries, without wiring, without an external power supply of any kind-just on the swelling and shrinking of gel,” said senior author David Gracias, a professor of chemical and biomolecular engineering at Johns Hopkins University. “Our study shows how the manipulation of shape, dimensions, and patterning of gels can tune morphology to embody a kind of intelligence for locomotion.”

Gracias envisions a range of practical future applications, including moving on surfaces through the human body to deliver targeted medicines. They could also be marine robots, patrolling and monitoring the ocean’s surface to combat pollution.

Researchers are planning to train the gelbots to crawl in response to variations in human biomarkers and biochemicals. They also want to test other worm and marine organism-inspired shapes and forms and would like to incorporate cameras and sensors into their bodies.

Journal reference:

  1. Aishwarya Pantula, Bibekananda Datta, Yupin Shi, Margaret Wang, Jiayu Liu, Siming Deng, Noah J. Cowan, Thao D. Nguyen, and David Gracias. Untethered unidirectionally crawling gels driven by asymmetry in contact forces. Science Robotics, 2022; DOI: 10.1126/scirobotics.add2903