Magnetic spray turns objects into mini robots that can deliver drugs

A glue-like magnetic spray can turn objects, such as pills, into mini robots that can be controlled by magnets and navigated through the body. The sprayed objects can be made to roll, flip and crawl using a magnetic field. Shen Yajing at City University of Hong Kong and his colleagues even used the spray to animate the wings of an origami crane. "Our spray can convert various tiny objects to mini robots directly," says Yajing. The object can be flat or three-dimensional and only a thin coating of spray is required, he says.