Toothbrush zaps bacteria with electricity that’s made when bristles move

Researchers at Peking University in Beijing have developed a toothbrush in which bacteria are destroyed not only by mechanical friction, but also through an electrical charge that is generated by brushing. The work was published in Science Advances on 4 November1.

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

The researchers showed that the brush did not damage the surface of the teeth and was not toxic to human cells, but they did not look at long-term safety or cost.

Curtailed bacteria

Bristled toothbrushes — which humans have used in various forms since the tenth century ad — rely mainly on motion to manually disrupt plaque, the film of bacteria, saliva and food particles that forms around teeth.

The team made the bristles from polyvinylidene fluoride, a polymer that they stretched and heated to obtain a piezoelectric form — meaning that it generated 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 molecules damage the cell membranes of bacteria in the plaque, say the researchers. When the bristles relax, the material reabsorbs the charges.

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