Dental hygiene goes bionic

In a futuristic world, man combines with machine to eliminate biological problems such as disease. That might sound like the setup to a science fiction movie, but it could become reality. New technologies combine electronic machinery with biological tissue to help with health problems. Electronic tattoos, which adhere to the skin in a fashion similar to that of an ordinary temporary tattoo, promise to help monitor heart rate, muscle activity and other things currently observed with wires and monitors.

A new tattoo you will not even feel. Image from Technology Review.

One such tattoo-like device has been in development by researchers at Princeton University. Using silk strands and gold wires, this sensor adheres to the enamel of a tooth and is able to detect things like bacteria, DNA, and even certain viruses. Its ability to detect bacteria on a small scale could make the device an important tool for treating diseases according to team lead investigator Michael McAlpine.

The device was constructed using a silk base. Researchers then imprinted graphene (an incredibly thin layer of carbon) sensors to the base. They then created an antenna using thin gold strands. This resulted in a thin, flexible device similar to a removable tattoo. The device adheres to tissue by dissolving away the silk base using water. The silk base dissolves away but the graphene and antennae remain firmly in place.

To detect bacteria, researchers placed peptides on the graphene sensors which combine with bacterial cells that produce a signal picked up by the antenna. A radio placed nearby delivers a signal that causes the antennae to resonate and transmit back its signal. Because of this, the device needs no battery or other power supply. The antennae coil is what transmits the signal.

The coil of the antenna has to be large enough to transmit a readable signal, so the current version of the device is not small enough to fit on a human tooth. Researchers have tested the device using a cow’s tooth but they are confident that with further work they will be able to make the antennae coil smaller.

Because of the silk base, the device can stick to more than just tooth enamel. It can also be integrated onto other biological tissues. The researchers tested this with a raw chicken breast.

They were also able to place the device on non-biological tissues such as an IV bag. According to the researchers, this could have amazing potential in a hospital setting. They poured an IV solution containing bacteria into the IV bag and the device was able to detect Staph. aureus, a common cause of nosocomial infections (hospital-acquired infections).

In addition to making the device smaller, researchers are also working on increasing its longevity. The soluble silk base could eventually be completely washed away by water or the body’s enzymes. Furthermore, they are looking for ways to protect it from external damage caused by teeth-brushing.

According to McAlpine, they still have a ways to go before they are able to make the device last as long as they want it to. Once it is working as desired, however, it will be able to accurately monitor our health and take us one step closer to a disease-free world.