Bacteria that cause tooth decay could be blasted away by microscopic “bombs” detonated with an ultrasonic toothbrush.
Ultrasound can cause some liquids, such as perfluorohexane (PFH), to rapidly expand and turn to gas. Some researchers have explored using tiny degradable capsules containing these liquids to deliver drugs inside the body or to blast away cancerous tumours.
Now, at Wuhan University in China and his colleagues have developed PFH-containing capsules designed to destroy biofilms – aggregations of microbes on a surface – which are a common cause of tooth decay and infection.
Advertisement
The micrometre-sized capsules, which Zhang and his team named microbombs, contain molecules of calcium peroxide, iron and tannic acid. When hit with ultrasound, the PFH causes the microbombs to break apart, triggering a chain reaction that converts the calcium peroxide to hydrogen peroxide, which destroys biofilms.
Ultrasonic toothbrushes, which produce high-frequency sounds above the human hearing threshold to dislodge bacteria-filled plaque from teeth, can be used to detonate the microbombs.
To test their effectiveness, Zhang and his team treated biofilms derived from human saliva with the microbombs and ultrasound and found no detectable bacteria survived.
They then tried treating rats that had dental plaque with a microbomb-laden toothpaste and ultrasonic toothbrush every day for three weeks. Two other groups of rats were given a common oral antiseptic or no treatment at all. The group treated with the microbomb toothpaste had the least enamel damage and cavities.
This use of microcapsules is novel, says at the University of Leeds, UK, but it is unclear how much better it might be for destroying biofilms than a regular toothbrush. It would be interesting to see how effective it is at disrupting biofilms in more hard-to-reach places, like inside the body, he says.
Advanced Functional Materials
