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"Plaque Attack" -- The Discovery Files

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A team of engineers, dentists and biologists has developed a microscopic robotic cleaning crew, which goes by the acronym "CARs," whose catalytic activity could ably destroy biofilms, sticky amalgamations of bacteria enmeshed in a protective scaffolding. The scientists tested the minibots mettle in fighting tooth decay and infection from plaque; however, their biofilm-removal systems also could be valuable in a wide range of potential applications, from keeping water pipes and catheters clean to reducing the risk of implant contamination.

Credit: NSF/Karson Productions

Audio Transcript:

Cleaning crew.

I'm Bob Karson with the Discovery Files, from the National Science Foundation.

Scrape. Scrape. Dig. Scrape. Seems no matter how much you brush (Sound effect: brushing sounds) or floss (Sound effect: cartoon flossing sounds), a good cleaning at the dentist always turns up the dreaded plaque. Basically, a microbe-infested biofilm -- millions of bacteria in a tough matrix that builds on itself. It even sounds bad. "Plaaaque."

At the University of Pennsylvania, a team of engineers, dentists and biologists is collaborating to attack plaque in a novel way. By putting a microscopic robotic cleaning crew right in your mouth. They're called 'CARS' -- catalytic antimicrobial robots.

The team developed CARS packed with iron-oxide nanoparticles in a solution. Directed by magnets, they push plaque off the surface like a tiny plow. Their second type of micro-bot targets and destroys biofilms clogging enclosed tubes. In tests, both worked with high precision on a flat glass surface, inside tubes and yes, on the hard-to-reach, irregular nooks and crannies of human teeth (Sound effect: toy teeth chatter) degrading the protective matrix, killing the embedded bacteria, and removing the biofilm. Gone.

The system is being considered for removing biofilms from water pipes, catheters, implants and more. An army of plaque-busting bots should give all of us another reason to smile.

"The discovery files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.

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