Robots made from sticky tape and dust can morph into various shapes under the direction of a magnetic field. They may one day be able to crawl into computers to or even inside the human stomach to apply therapeutic patches to gastric ulcers.
Soft robots that have no batteries, motors or electronics and that are powered and controlled from a distance by light or magnets are a popular field of research. But there are barriers to overcome before they can be used in practical applications, including the need for a cheap manufacturing process.
Zhang Li at the Chinese University of Hong Kong and his colleagues discovered that a magnet-controlled robot can be created easily and at low cost using sticky tape onto which non-sticky wax has been printed in a specific pattern. When powder containing microparticles of magnetic neodymium-iron-boron is applied to the tape, it sticks to the exposed sections but not to the wax overlay – a little like a stencil. The wax is then dissolved in ethyl acetate solution to leave an accurately shaped magnetic robot.
Zhang says that the process could be easily automated and that tiny robots could eventually be printed in long rolls, just like newspapers coming off a printing press.
Advertisement
In experiments, his team created sticky tape robots of various shapes around across that change their geometry depending on the presence and orientation of a magnetic field.
A small robot made from sticky tape and metal powder
Zhang Li
Zhang says that these devices could be used in the future to deliver drugs or carry out simple medical procedures in the stomach or intestines. “It can be deployed in this kind of folded, small scale, and when it reaches a large cavity it can open up,” he says. “It’s very much like a satellite, where after its launch into outer space the solar panels will open up. So when you swallow this device, it should have a very small size.”
There are hurdles to overcome prior to clinical trials, however. “The first thing is safety, because currently we’re using a very strong magnet called a neodymium-iron-boron magnet. It’s actually not that safe,” says Zhang. “It’s kind of toxic to the cells.”
Co-author Xiaoguang Dong at Vanderbilt University in Tennessee says their team first tried to add that clamp down on tissue, inspired by the way some intestinal parasites attach themselves. But they had trouble reproducing the high forces required – and getting the robot to release its grip was also tricky, he says.
When covered with a thin layer of chitosan (a substance found in shrimp shells), the foot’s created just enough increased friction and stickiness for the feet to latch on to the mucus layer inside pigs’ lungs and digestive tracts – including the bronchial tubes and intestines – and then pull away to take a new step.
In a series of laboratory tests, the researchers found that the robot will keep climbing along and clinging to “highly slippery” and often wrinkled biological tissue, even when the tissue is shaken or flushed with water.
The researchers controlled the robot’s movement inside the organs by using a nearby machine that manipulates magnetic fields. Because the robot’s body is made of magnetic metal, it bends and turns in response to the machine’s commands, says Dong.
The ultrathin, with a body 3.7 mm long and 1.5 mm wide. It can carry “cargo” three times its own volume and up to 20 times its own weight, says co-author.at the Max Planck Institute. That means it could transport medications, wireless electronic sensors or even possibly biopsy materials. It can also release microscopic drug particles through its
Because only to the mucus layer, they cause no damage to the tissue itself, says Wu.
You must be logged in to post a comment.