As the inside of the human body consists of delicate organs, the soft innards may not cope well when hard objects are placed inside. The sharp edges may damage the organs and blood vessels, and the body’s immune reaction may interfere with the targeted function of the foreign object.

Hence, researchers have been working on soft robots that allow better tolerance within the body and allow intimate contact between the machines and human tissues without any health threats.

Below are three experimental robots designed for different medical purposes such as surgical tools and implants; all are a gentler kind of robotics made by new materials and flexible actuators.

1. Soft robotic arm

Invented by a team of Chinese postgraduates from Beijing-based Beihang University, a robotic arm inspired by tentacles of an octopus can be used to heal injuries.

“The softness makes it possible for the robots to work more effectively and safely with humans and can be used for rehabilitation and recovery or in the service sector,” said Wang Tianmiao, a robotics engineer at the university.

“It can bend and swirl quickly, and the suction cups help it adhere tightly to objects of different shapes and sizes,” said Wang. Soft robots are made up with materials such as silicone, plastic, fabric, rubber or compliant mechanical parts like springs.

According to Wen Li, associate professor in Beihang University and head of the team, the robotic arm will have medical application in minimal-invasive surgery and athletic rehabilitation in five to ten years.

2. Drug doser

By replicating a watch mechanism called the Geneva drive in a soft hydrogel, a group of creative and innovative researchers at Columbia University created a soft clockwork biobot that could tick along to release doses of drugs from inside the body.

Samuel Sia, a Columbia University professor of biomedical engineering, invented the watch-inspired biobot with a simple hydrogel gear. The hydrogel gear is embedded with iron nanoparticles so that researchers can turn it with an external magnet. With a click forward, a dose of liquid will discharge by bringing a hollow chamber into line with an opening.

“In cancer care, such implants could enable the localised delivery of a chemotherapy drug and spare the rest of the body from the drug’s toxic effects,” said Sia.

The drug doses delivered by the biobot were tested in mice with bone cancer were found to kill more tumour cells and spare more surrounding healthy cells than a typical systemic chemotherapy treatment. An external controller would also allow the doctor to have flexibility in controlling the delivery of drug doses.

“The trickiest part of the design process was getting the material just right,” Sia said. “It has to be stiff enough to work like a tiny implantable machine.”

3. Hydrogel ‘hands’

A research study led by Xuanhe Zhao, an MIT associate professor in mechanical, civil and environmental engineering departments, devised a series of robotic gadgets made of hydrogel and powered by water.

Each robot is fabricated in the form of interlocking cubes with hollow interiors. The movement of the robot, which either bends or stretches, is activated once water is pumped in and out of them. The fast and forceful movements can perform various tasks, which includes kicking a ball or grabbing and releasing live fish.

“Hydrogels are soft, wet, biocompatible and can form more friendly interfaces with human organs,” said Zhao in an MIT news release. She also said the robots are safer for biomedical use since the hydrogels contain mostly water.

“We are actively collaborating with medical groups to translate this system into soft manipulators such as hydrogel ‘hands,’ which could potentially apply more gentle manipulations to tissues and organs in surgical operations.” MIMS

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