Scientists Create Programmable Nanoparticle Toothbrush
The basic design of the toothbrush hasn’t changed in a thousand years — sure, there are motors, different materials, and funky shapes, but they’re all still sticks with bristles attached. A team from the University of Pennsylvania believes it’s time to shake things up. In a new study, the researchers have shown that shapeshifting nanoparticles can successfully clean teeth, replacing all the manual labor with a nano-scale robotic dance. Not only can these particles be transformed into tooth-cleaning shapes, but their action can have antimicrobial effects that destroy plaque-causing bacteria.
This project came together quite by accident. A group from the Penn School of Dental Medicine under professor Hyun (Michel) Koo was interested in leveraging the catalytic activity of nanoparticles to release free radicals that could kill microbes on the teeth. Meanwhile, senior engineering researcher Edward Steagar was spearheading work at the Penn School of Engineering and Applied Sciences on assembling nanoparticles into robots. Bringing these projects together gave us the sci-fi gray goo toothbrush.
The combined team used magnetic fields to manipulate iron oxide nanoparticles, testing them first on a slab of tooth-like material. Next, the team moved to 3D-printed copies of teeth. Finally, they tested the nanoparticle brushes on real teeth that were mounted in a realistic way to simulate a human mouth. The tests show these nanoparticles can form brush-like shapes capable of scrubbing off the biofilms that lead to tooth decay. They can also flow between teeth like floss. All the while, the nanoparticles promote the production of free radicals that further eliminate bacteria.
While the gray goo brush has not been tested in a real human mouth, the researchers are excited by the possibilities. The laboratory tests demonstrate that the nanoparticles can be programmed to do almost anything. They can simulate longer or shorter bristles, as well as varying degrees of stiffness. So, it may be possible to customize the system for each person’s individual oral health needs. This could help those who are just neglectful of oral hygiene, as well as those who lack the strength or manual dexterity to handle their own brushing.
Currently, the team is still studying ways to optimize the motion of the nanoparticles, as well as ways they could be delivered to and retrieved from a patient’s mouth. The university’s press release does not mention what a slurry of iron oxide nanoparticles might taste like. Our guess is “not great.” Hopefully, that problem is on the team’s radar as well.