Humanoid robots aren’t just science fiction anymore; in fact, they’re almost ready to enter the workforce. Amazon has been exploring replacing some of its warehouse staff with robots, and Elon Musk is also considering the potential of robotic helpers.

The latest developments come from scientists at the University of Tokyo, who have created a type of skin from human cells. This pink, gooey material can stretch into what resembles an awkward smile.

Researchers use a special gel loaded with skin-forming cells to sculpt a “living layer” that adheres to robotic surfaces, bringing biology into play when the robot smiles.

Researchers believe this technology could enhance our understanding of facial expressions and advance treatments for facial paralysis, as well as improve cosmetic and orthopedic surgeries. In the future, stroke patients and burn victims who have undergone major surgeries could benefit from more natural skin augmentations.