Microscale acoustic “rockets” navigate the human body

Ever since nanotechnology became a real branch of engineering, its practitioners have been trying to design tiny structures that can work like submarines to navigate through the human body.

One stumbling block towards this goal has been what fuels and motor analogues could be used to propel and steer such nanovessels around and inside blood vessels and organs without causing harm.

Researchers at Pennsylvania State University and the University of San Diego hit a wall with their research, because they were using toxic materials like hydrogen peroxide as fuel. A fortuitous discovery about the behaviour of bubbles has opened up a new avenue for their research, as they describe in Science Advances.

Working with material scientists at the Harbin Institute of technology in Shenzhen and surgeons at University of Michigan, Thomas Mallouk of the Department of Chemistry at Penn State was trying to move nanovessels with acoustic levitation, a technique used to lift particles off microscope slides. Unexpectedly, he found that high-frequency sound waves made the vessels move at very fast speeds. Investigating this phenomenon further, Mallouk and his team designed microscale “rockets” that can use acoustics to zip around and steer in a liquid medium.