Those who have lost their sense of taste or who have difficulty monitoring what they eat may soon be fitted with an artificial taste-sensing system to help them manage their diet.

A team of researchers led by Richard Costanzo, professor of physiology and biophysics at Virginia Commonwealth University (VCU), has developed a device mounted on an orthodontic retainer that may be worn inside the mouth to assist such people. The technology uses sensors to measure the concentration of sodium ions coming in through the mouth. It transmits the data to a smartphone or other monitoring system. Once the sodium threshold is reached for the day, the user is alerted.

Sensors are mounted on an orthodontic retainer worn inside the mouth. Image credit: VCU.Costanzo says he believes that the device could also teach people to modify their eating behavior in a way similar to other biofeedback apps, like a Fitbit.

The sodium-sensing system starts with a microcircuit pattern developed by Hong Yeo, assistant professor of mechanical and nuclear engineering. Yeo's sensor consists of a copper membrane circuit 200 nanometers in diameter (100 times thinner than a strand of human hair), a data-processing chip that converts the analog data from the sensors into digital data and a Bluetooth chip that transmits the digital data to a wireless receiver or smartphone.

All of this fits onto a piece of flexible elastomer slightly thicker than an adhesive bandage and that measures two square inches. “The advantage is that it can be bendable and stretchable without fracturing the material, so we can put it on pretty much any surface,” Yeo says.

In subsequent versions, the taste sensor will expand to include the other four tastes: sour, sweet, bitter and umami.

Eventually, Costanzo and Yeo want to connect their sensor with the body. Much like an implant stimulates cochlear nerves to help a deaf person hear sounds, an internal taste implant would receive data from food molecules and stimulate the appropriate nerves to create a perception of taste.