Nobody likes a mess, even a microscopic one. For one thing, it´s tough to clean what you can´t see. That´s why researchers at Rensselaer Polytechnic Institute are crafting the world´s smallest brooms. The tiny tools are made by growing bristles of superstrong carbon nanotubes on a silicon-carbide fiber just 16 microns in diameter, or about half as thick as a human hair. Scientists create the “handle” by coating one end of the fiber with gold, which inhibits nanotube growth.
Fancy handles notwithstanding, it´s the brush´s multitalented bristles that take its potential applications beyond the janitorial. Nanotubes—cylinders of carbon atoms about 30 billionths of a meter across—conduct electricity, so the brushes could be used in mini electric motors. They also absorb liquids and could paint microscopic surfaces. But lead investigator Anyuan Cao envisions the brushes doing their best work inside the human body. The researchers have already shown how the bristles could be connected to a small motor and used like a Roto-Rooter to clean out food pipes or blood vessels. They just need to make sure the bristles will stay attached to the handle. “We don´t want them shedding inside the body,” Cao says. “They´re very strong and very sharp.”