Graphene-based artificial tongue achieves near-human-like sense of taste

A team of researchers report in the Proceedings of the National Academy of Sciences on a new graphene-based sensor design that, through machine learning, was able to develop a near-human sense of taste. This device is the first of its kind to operate in a moist environment, better approximating the conditions inside the human mouth.

The sensor described in the paper was made of multiple layers of graphene oxide, a material well known for its tunable electrical properties and high chemical reactivity, enclosed in a nanofluidic device.

Like graphene, graphene oxide changes its electrical conductivity when exposed to different chemicals. The researchers used this property to measure electrical variations in the sensor when it was exposed to a sampling of 160 chemicals, each associated with a unique flavor profile. Using these data, a machine-learning algorithm was able to create a 'memory' of flavors.

This learning process is analogous to the way the human brain interprets signals from our taste buds when they react to chemicals in our foods. It was long held that humans could detect five distinct tastes: sweet, salty, bitter, sour, and umami. In 2023, researchers isolated a sixth flavor, ammonia chloride.

During testing, the new artificial tasting system's algorithm, which was trained to classify four basic tastes (sweet, salty, bitter, sour), could readily identify tastes it had already experienced with an accuracy of around 98.5%.

Image source: Zhang et al. (2025), PNAS.