In our inked up future, vibrating tattoos will buzz when your phone rings, and change color when your blood sugar is low. But a new kind of sensor made of graphene could one-up them all—tattooed to your teeth, these sensors will be able to tell when you’re ill, and even possibly what’s ailing you—all from the bacteria on your breath. A bonus: It won’t even hurt to put them on.
"It takes only a few bacteria to make you sick," Mike McAlpine, a graphene man at Princeton tells Co.Exist. "It’s something you want to be able to detect as quickly as possible and in very small concentrations."
McAlpine says the new super-sensitive graphene tattoo sensors could be used in war zones, where soldiers can quickly be diagnosed for bacterial infections from wounds. "In the battlefield and other places, you want to know very quickly what kind of exposure you have," McAlpine says. But the platform itself is modifiable so it could be tailored to detect almost anything biological.
Graphene, a layer of carbon that’s one-atom thick, is a super-sticky, super-sensitive surface. By planting carefully constructed peptides (a short sequence of amino acids) onto the surface of graphene, McAlpine and his group have shown that the sensors can detect bacteria individually, picking them up like velcro.
The sensors could be used in hospitals, where infections of the antibacterial resistant superbug MRSA linger undetected on IV bags, shower curtains, and countless other surfaces. "One thing we show is that we can also print it onto IV bags and do a sensing of bacteria," McAlpine says.
The graphene sensors could also be used to test the viability of food—something the group tested by stamping the sensors onto a chicken breast. The group also tested the sensors on an extracted cow tooth. "I sent a couple of students to the farm to get a cow tooth. For some reason they had it on hand. I don’t know why," McAlpine said. As this video shows, when a grad student breathes onto the sensors planted on it, the computer picks up molecules on his breath. The cow tooth also picked up molecules in saliva.
The graphene sensors are supported on a silk film and implanted onto a surface. The silk film—made of proteins—dissolves away, leaving the graphene sensor painlessly pasted into place.
The group has already shown off an edible sensor made of paper-thin gold coils supported on digestible silk film, which can tip you off when your food is spoiled.
McAlpine and his team are planning to license and commercialize the graphene sensors. There’s still work ahead though—in their present form, the sensors are too big to be practical. Next up, the group is working on shrinking the sensors to actually fit on a human tooth.