ARRANGED IN BRISTLE-LIKE STRUCTURES, A ROBOTIC MICROSWARM OF IRON OXIDE NANOPARTICLES DEVELOPED BY A TEAM FROM THE UNIVERSITY OF PENNSYLVANIA EFFECTIVELY CLEANED PLAQUE FROM TEETH. THE NANOPARTICLES HAVE BOTH MAGNETIC AND CATALYTIC PROPERTIES; CATALYZED HYDROGEN PEROXIDE PRODUCED FREE RADICALS THAT ELIMINATED TOOTH DECAY-CAUSING PATHOGENS AS WELL