NEW YORK • The idea sounds like fantasy: An invisible film that can be painted on your skin and give it the elasticity of youth. Bags under the eyes vanish in seconds. Wrinkles disappear.

Scientists at Harvard and the Massachusetts Institute of Technology have discovered that it is not fantasy at all.

Reporting on Monday in the journal Nature Materials on pilot studies with 170 subjects, the researchers say a "second skin" composed of commonly used chemicals deemed safe by the Food and Drug Administration can accomplish that - and in small studies of it, so far no one has reported irritation or allergic reactions.

The chemicals used are siloxanes - their basic form is one atom of oxygen linked to two atoms of silicon - which form polymers, long chains of repeating units. The researchers made a large collection of them by modifying molecular features such as the chain length to get the ones with the properties they wanted.

Researchers expect the technology can be used to treat eczema, psoriasis and other skin conditions by covering dry itchy patches with a film that moisturises and soothes.

NEW YORK TIMES