Magnetic spray turns objects into mini robots that can deliver drugs

By Ibrahim Sawal

City University of Hong Kong

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. The substance, dubbed M-spray, is made from polyvinyl alcohol, gluten and iron particles.

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The spray coating can be removed using an oscillating magnetic field to break it down into powder, leaving the object intact, says Yajing. This could prove useful for delivering pills to a particular location. The remaining powder can be absorbed or excreted by the body, says Yajing.

The team tested this by successfully manoeuvring and disintegrating an M-spray-coated drug to a target area in an unconscious rabbit’s stomach.

“With biocompatible components and side effects from its disintegration negligible, it makes a good candidate for biomedical applications” says Xinyu Wu at Shenzhen Institute of Advanced Technology, China.

Journal reference: Science Robotics, DOI: 10.1126/scirobotics.abc8191