When was the paintbrush first utilized?

An ancient paintbrush used by a prehistoric cave artist survives from 30, 000 years ago. But the bristles of the new nanobrushes are made of tiny carbon filaments—thirty billionths of a meter across and a few millionths long. The brush handles they’re attached to are comparatively large—thicker than a human hair! The researchers have taken microscope pictures showing the brushes can be used to sweep up tiny pieces of nanodust on dirty surfaces.
     The researchers also used their brushes to paint microstructures; and by coating the hairs with absorbent com- pounds, they could soak poisonous substances from water. If the tiny tools prove robust enough, they could one day find medical uses, or sweeping away unwanted dirt.