A team from the City University of Hong Kong has developed a coating that will turn objects into biocompatible millirobots for healthcare applications.

The coating, which behaves like a glue, is a magnetic spray called M-spray made up of gluten, polyvinyl alcohol (PVA) and iron particles. Applied to 1D, 2D or 3D objects to serve as millirobots, the spray will adhere to virtually any surface — skin, glass, wood or sand, for example — forming a 0.1 mm to 0.25 mm thick film. Once applied, the coating is exposed to heat to solidify the bond.

When introduced to a magnetic field, the M-spray is activated, enabling the coated millirobot to crawl, walk, flip or roll. According to its developers, the coating can enable operators to reprogram the millirobots’ mode of locomotion — a characteristic that is typically unchanged once a robot is constructed.

In addition to being reprogrammable, the film is also biocompatible and, when saturated, will disintegrate into a powder that can be excreted by the body, making it appropriate for drug delivery or catheter navigation applications.

The research appears in the journal Science Robotics.

To contact the author of this article, email mdonlon@globalspec.com