Gold, silk and graphite may not be the first materials that come to mind when you think of cutting-edge technology. Put them together, though, and you’ve got the basic components of a new ultra-thin, flexible oral sensor that can measure bacteria levels in the mouth. The device, attached temporarily to a tooth, could one day help dentists fine-tune treatments for patients with chronic periodontitis, for example, or even provide a window on a patient’s overall health.
The sensor, dubbed a “tooth tattoo,” was developed by the Princeton nanoscientist Michael McAlpine and Tufts bioengineers Fiorenzo Omenetto, David Kaplan and Hu Tao. The team first published their research last spring in the journal Nature Communications.
The sensor (A), attached to a tooth (B) and activated by radio signals (C), binds with certain bacteria (D). Illustration: Manu Mannoor/Nature Communications
Before the tooth tattoos can undergo clinical testing, however, researchers will have to overcome some limitations. In order for the sensor to detect specific strains of bacteria, McAlpine says, his team will need to create new peptides or similar molecules that bond with only one particular strain. Constructing those won’t be easy. McAlpine notes that he’ll need to work with biologists to build them from the ground up, a process that could require the development of entirely new methods for assembling organic molecules in the lab.
The sensor’s physical size is also a consideration: the prototype is a bit too large for use in humans (the team tested it on a cow tooth), so making the whole package smaller will be another challenge. And, Kugel notes, thickness is a factor, too. It’ll be important to determine if patients will accept having a foreign object, no matter how thin, attached to their teeth.
“People are very sensitive,” Kugel says. “They can feel objects in the mouth that are 50 or 60 microns across”—about the thickness of a sheet of paper. “If it’s at all irritating to a patient, he or she will complain about it. You’d need to make sure it’s actually comfortable enough to leave in place for long periods of time.”
[David Levin is a freelance science writer based in Boston. This story was first published on TuftsNow, Nov. 1, 2012.]