One name, two fields
“Artificial skin” refers to two quite different lines of technology. One is medical: materials and cultured tissue used to cover or help rebuild skin lost to severe burns and wounds. The other is electronic: thin, flexible sheets packed with sensors that give robots, prosthetic hands and wearable devices a sense of touch. They share an inspiration but little else, and their histories developed separately.
Skin substitutes for burns
Treating deep burns has long depended on grafting a patient’s own healthy skin onto the wound. That works, but a patient with very large burns may not have enough undamaged skin to donate. Without covering, burns are open to infection and fluid loss, which is why substitutes have been sought for much of the modern history of burn care. Earlier measures included skin from donors and animals, which the body usually rejects over time, so they served as temporary coverings at best.
Two important advances arrived in the 1970s and early 1980s. In the mid-1970s, James Rheinwald and Howard Green at Harvard Medical School showed how to grow human skin cells, called keratinocytes, in the laboratory in large numbers. In the early 1980s, a team including Nicholas O’Connor, Howard Green and colleagues applied sheets of cultured cells grown from a patient’s own skin to burn patients. The method can multiply a small skin sample into large sheets, though it takes weeks to grow them and the new skin can be fragile, which is why it is generally used with other treatments.
Meanwhile, Ioannis Yannas, an engineer at the Massachusetts Institute of Technology, and John Burke, a surgeon at Massachusetts General Hospital and the Shriners Burns Institute, worked together on a different approach in the 1970s. They developed a layered material built from collagen and a sugar-based molecule, intended as a scaffold the body could grow into, with a thin temporary outer layer. The material is not a living skin. It acts as a template on which the patient’s own tissue can rebuild. A product based on this work won approval from the U.S. Food and Drug Administration in the mid-1990s.
Since then researchers have developed a range of dressings, scaffolds and engineered tissues, some including living cells, and work continues on bio-printing approaches that borrow from additive manufacturing. No substitute fully matches natural skin, which includes hair follicles, glands, nerves and blood vessels. Treatment decisions belong to clinicians, and this article covers history only.
Sensor skins for robots
The electronic story starts from a practical problem. Early industrial robots could move precisely but could not feel what they touched, so they depended on fixed positions and clever fixtures. In the 1970s and 1980s researchers experimented with tactile sensors for robot hands, using pressure-sensitive rubber, tiny switches and arrays of small elements. Those early sensors were typically stiff, limited in number and hard to wire up.
By the 1990s some groups, including work associated with Vladimir Lumelsky at the University of Wisconsin, considered covering whole robot arms with “sensitive skin” so a machine could notice nearby objects and people and avoid collisions. This was influential as a concept, but the technology of the time made large, flexible, reliable coverings hard to build.
Stretchable and flexible electronics
A shift came in the 2000s and 2010s with progress in flexible and stretchable electronics. Teams including those of Takao Someya in Japan, Zhenan Bao at Stanford and Ali Javey at the University of California, Berkeley, reported thin, bendable films that could sense pressure, temperature or both and in some cases be stretched without breaking. These were frequently described as “electronic skin” or “e-skin.” Researchers explored materials such as conductive polymers, tiny metal structures and graphene.
The same ideas drive current interest in covering prosthetic hands with touch sensors, with experimental systems linking signals to the nerves or skin of the wearer. Some experimental robots also use fabric-like sensor layers for safer contact with people. In both cases, laboratory demonstrations are still more common than everyday products, and durability, calibration and cost remain obstacles.
How the two threads relate
The medical and electronic uses differ in aim. Medical skin substitutes try to help living tissue heal, so success depends on biology and safety testing. Sensor skins try to measure the world, so success depends on materials science, signal processing and manufacturing. Projects that try to combine them, such as a covering that heals itself or that gives a prosthesis a convincing sense of touch, remain research goals.
A useful rule when reading about artificial skin is to check which kind is meant. News of a skin that “feels” is about electronics. News of a skin that “heals” burns is about tissue engineering. Neither is a finished replacement for natural skin.