3D-printed human tongue developed for food tests and dry mouth cures

Scientists have 3D-printed synthetic, soft surfaces with tongue-like textures that could be used to test the oral processing properties of food, nutritional technologies, pharmaceutics and dry mouth therapies.

 The highly sophisticated surface design of a human tongue has been replicated with a synthetic silicone structure that mimics the topology, elasticity and wettability of the tongue’s surface.

The team took silicone impressions of tongue surfaces from fifteen adults. The impressions were 3D optically scanned to map papillae dimensions, density and the average roughness of the tongues.

Computer simulations and mathematical modelling were hen used to create a 3D-printed artificial surface to function as a mould containing wells with the shape and dimensions of the different papillae randomly distributed across the surface with the right density.

The unique factors attributable to the human tongue are instrumental to how food or saliva interacts with it, which in turn can affect mouthfeel, swallowing, speech, nutritional intake and quality of life.

Social distancing measures brought in since the beginning of the Covid-19 pandemic have posed significant challenges to carry out sensory trials and consumer tests in the food sector.

The researchers believe their biomimetic tongue will be helpful to increase development productivity and reduce manufacturers’ reliance on human trials in the early stages.

“Harnessing expertise from multiple STEM disciplines, we’ve demonstrated the unprecedented capability of a 3D printed silicone surface to mimic the mechanical performance of the human tongue,” said professor Anwesha Sarkar from the University of Leeds.

The complex nature of the tongue’s biological surface has posed challenges in artificial replication, adding major obstacles to the development and screening of effective long-lasting treatments or therapies for dry mouth syndrome. Roughly 10 per cent of the general population and 30 per cent of older people suffer from dry mouth.

Dr Efren Andablo-Reyes, study lead author, said: “Recreating the surface of an average human tongue comes with unique architectural challenges. Hundreds of small bud-like structures called papilla give the tongue its characteristic rough texture that in combination to the soft nature of the tissue create a complicated landscape from a mechanical perspective.

“We focused our attention on the anterior dorsal section of the tongue where some of these papillae contain taste receptors, while many of them lack such receptors.

“Both kinds of papillae play a critical role in providing the right mechanical friction to aid food processing in the mouth with the adequate amount of saliva, providing pleasurable mouthfeel perception and proper lubrication for swallowing.

“We aimed to replicate these mechanically relevant characteristics of the human tongue in a surface that is easy to use in the lab to replicate oral processing conditions.”

It is hoped the ability to produce accurate replicas of tongue surfaces with similar structure and mechanical properties will help streamline research and development for oral care, food products and therapeutic technologies.