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New Magnetic Spray Transforms Objects Into Tiny Robots

New Magnetic Spray Transforms Objects Into Tiny Robots

Saturday, 21 November, 2020 - 07:00
Dr. Shen (Middle) & the team at CityU. Credit: City University of Hong Kong

Researchers from City University of Hong Kong (CityU) have developed an easy way to make millirobots by coating objects with a glue-like magnetic spray.

Driven by the magnetic field, the coated objects can crawl, walk, or roll on different surfaces. During the study, researchers tested the new technique in potential biomedical applications, including catheter navigation and drug delivery. The magnetic glue is biocompatible and can be disintegrated into non-harmful powders. The research findings have been published in the scientific journal Science Robotics on Wednesday.

Composed of polyvinyl alcohol, gluten, and iron particles, the magnetic spray (M-spray) can adhere to rough and smooth surfaces. The film it formed on the surface is just about 0.1 to 0.25mm thick, which is thin enough to preserve the original size, form, and structure of the objects.

When coated with the magnetic spray, the object could be driven by a magnetic field and can be transformed into millirobots with different locomotion modes, such as crawling, flipping, walking, and rolling, which make it useful in various applications. In experiments involving animals, researchers found that magnetic spray-coated catheters were better than the conventional ones.

The researchers also used the magnetic spray to coat drug particles and transform them into millirobots that can reach a targeted location rather than scattering in the body, which could increase the efficiency of the drug. The team conducted in vivo test with rabbits and capsule coated with M-spray. The position of the capsule in the stomach was tracked by radiology imaging. When the capsule reached the targeted region, the researchers disintegrated the coating by applying an oscillating magnetic field.

"All the raw materials of M-spray are biocompatible. The disintegrated coating could be absorbed or excreted by the human body with no side effects," said lead author Shen Yajing, associate professor of the Department of Biomedical Engineering (BME) at CityU in a report published on the university's website.

"Our experiment results indicated that different millirobots could be constructed with the M-spray adapting to various environments, surface conditions, and obstacles. We hope this construction strategy can contribute to the development and application of millirobots in different fields, such as moveable sensor, particularly for the tasks in limited space," he added.

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