Photo Credit: Michael McAlpine

Gold teeth have been around for decades, and some have even adopted the look as a fashion statement. Soon, though, a blinged-out grill might be able to provide early warning for health conditions.

Engineers at Princeton University have developed a tattoo-like dental sensor that can detect bacteria—down to the molecular level—even a single bacterium—that could cause surgical infections and stomach ulcers. The contraption uses nanosensors made from a carbon-based substance called graphene and a tiny antenna coil formed from gold wires to monitor breathing and saliva, then transmit readings wirelessly. A radio transmitter held within a centimeter of the sensor sends a signal that activates the coil and causes the sensor to send back data, according to a report in the journal Nature Communications.

"This is a real-time, wireless response from a sensor that can be directly interfaced with a variety of biomaterials," principal investigator Michael McAlpine, of Princeton's Department of Mechanical and Aerospace Engineering, tells the university's news service.

A base of silk, created by biomedical engineers at Tufts University, makes the device more comfortable, and because silk is water-soluble, the base washes away after application, leaving the sensor and transmitter in place. "When you make biosensors the traditional way, silicon is the substrate," lead author Manu Mannoor, a Princeton graduate student, explained. "When you think of interfacing that on the body, silicon is very brittle. Silk allows for a dissolvable platform."

For the study, the Princeton team tested the sensor on a cow's tooth. The current prototype is not small enough to fit on human teeth, and the researchers are not yet confident it could stand up to brushing or other abrasion. Further studies are planned to test the adhesion between graphene and tooth enamel.

"Ideally, you want something that would be there [on the tooth] for a while," McAlpine says. "We have a ways to go before we could master that."