'Super skin' that can sense a fly land

Bao is working to add the ability to detect chemicals and sense various kinds of biological molecules, the journal Advanced Materials reports.

"With artificial skin, we can basically incorporate any function we desire," said Bao, Standord professor of chemical engineering. "That is why I call our skin 'super skin'. It is much more than what we think of as normal skin."

Bao said she sees the super skin as much more than a super mimic of human skin. It could allow robots or other devices to perform functions beyond what human skin can do, according to a Stanford statement.

The foundation for artificial skin is a flexible organic transistor, made with flexible polymers and carbon-based materials. To allow touch sensing, the transistor contains a thin, highly elastic rubber layer, moulded into a grid of tiny inverted pyramids. When pressed, this layer changes thickness, which changes the current flow through the transistor.

The sensors have from several hundred thousand to 25 million pyramids per square centimetre, corresponding to the desired level of sensitivity.  To sense a particular biological molecule, the surface of the transistor has to be coated with another molecule to which the first one will bind when it comes into contact.