Counterfeiters who sell knockoffs of popular shoes,
handbags and other items are becoming increasingly sophisticated,
forcing manufacturers to find new technologies to stay one step
ahead. Now, researchers reporting in ACS Nano have developed tiny
“Janus balls” that show their colored side under a magnetic field.
These microparticles could be useful in inks for
anti-counterfeiting tags, which could be verified with an ordinary
magnet, the researchers say.

