Researchers at Peking University in Beijing have developed a battery-less brush that destroys bacteria by generating its own electrical charge, rather than relying on mechanical friction alone. The work was published in Science Advances on 4 November¹.

Generating electricity from brushing is a “new twist on an old concept,” says Frank Scannapieco, a periodontist and microbiologist at the University of Buffalo in New York. It might reduce plaque more efficiently, although more tests are needed to prove efficacy and safety, he says.

Curtailed bacteria

Bristled brushes — some form of which humans have used to clean teeth since the 10^th century CE — primarily rely on motion to manually disrupt plaque, the films of saliva around teeth in which communities of bacteria grow.

The researchers made the bristles from polyvinylidene fluoride, a polymer which they stretched and heated to obtain its piezoelectric form — meaning it generates a charge when deformed.

When used to scrub teeth, the bending bristles release charges that create highly reactive forms of oxygen in nearby saliva. These damage bacteria cell membranes, say the researchers. When the bristles relax, the material reabsorbs the charges.