Scientists in the United States have invented “electronic skin” patches that monitor people’s vital signs and will ultimately be able to wirelessly transmit information to a health professional.

Dr John Rogers reported on the development at the 243rd National Meeting and Exposition of the American Chemical Society at the start of this week.

Dr Rogers developed the electronic skin patches with colleagues at the University of Illinois at Urbana-Champaign.

He told the meeting the patches have the potential to eliminate the need for patients to stay tethered to large machines in a doctor’s office or hospital room for hours of treatment or monitoring.

"A key feature of our epidermal electronics is its natural interface to the body, without wires, pins, adhesives or gels, to allow a much more comfortable and functional system," said Dr Rogers.

"The technology can be used to monitor brain, heart or muscle activity in a completely noninvasive way, while a patient is at home."

The patches are about the thickness of a human hair, and wearers can’t feel them on their skin.

Despite their miniscule dimensions, they can carry full-scale electronic circuits needed to monitor health status.

The developers plan to add wi-fi capabilities which would mean the electronic skin could also send information back to a health professional.

Dr Rogers said he and his colleagues developed the patches to be flexible and stretchable, to move with the natural motions of the skin as people go about their day.

He said silicon-based wafers typically used for electronics, such as laptops and smartphones were hard and brittle, like glass.

To form a material that bends and stretches like skin or rubber, they had to use very small pieces in a wavy pattern.

The patches are transferred to the skin just like a temporary tattoo, with water and a backing that peels off.

A spray-on bandage protects the circuit from water and normal wear-and-tear and keeps it on the skin for up to a week.

"We’ve also figured out how to make the devices operate in a bi-directional way," Dr Rogers explained.

"The older devices only measure what’s going on in the body. Our newest patch can measure muscle activity and stimulate the muscles.

"That’s useful for rehabilitation after an accident or long periods of bed rest or even for helping people move prosthetic limbs more easily."

Dr Rogers has co-founded a company which is putting the patches on medical instruments that go inside the body, such as catheters.

The electronic skin patch is placed on the outside surface of the catheter so that when it expands in the heart, the patch expands with it and touches the inside of the heart, taking measurements used to guide surgery.