Synthetic ‘second skin’ uses science to make you look younger

Want to erase those crow’s feet or shrink those eye bags? In the future, rather than getting injections or going under the knife, you may be able to solve those cosmetic problems by painting on a second skin.

Researchers at Harvard and MIT have created a transparent, silicone-based polymer that can be layered onto human skin to protect it from sun damage and even smooth out wrinkles.

The stretchy new material, described in the journal Nature Materials, is flexible, breathable, invisible and water-resistant. Aside from its cosmetic potential, the so-called second skin could one day be used to protect skin against sun damage or to deliver drugs and treat a range of skin diseases such as eczema and psoriasis.

“A wearable material layer that restores the normal skin mechanics and appearance is unprecedented and provides a platform to solve other cutaneous problems,” the study authors wrote.

Though it looks nothing like your stomach or spleen, your skin is an organ – the largest and most visible one the body has. And like other organs, it performs several essential functions, such as keeping out pathogens and toxins, protecting your internal organs from radiation and, by sweating, maintaining your body temperature.

Skin is also a useful, noninvasive route for delivering drugs over an extended period; nicotine patches may be the best-known example. Skin is also filled with nerves that allow us to navigate our complex world – and particularly on our faces, it makes what the study authors called “a psychosocial statement about the health of the individual.”

Of course, sometimes our skin makes statements we haven’t signed off on, whether it’s adolescent acne outbreaks or wrinkles and other signs of aging, and it can fall victim to a host of ailments.

Researchers have tried to develop treatments that restore several of skin’s functions simultaneously, but it turns out to be a nearly impossible juggling act.

“You want it to be clear, so it’s sort of like a transparent second skin,” said senior author Robert Langer, a biomedical engineer at MIT, ticking off such a material’s desired qualities. “You want it to be mechanically strong, you want it to conform to the skin ... and obviously, you want it to be safe.”

Such a material would also have to be oxygen permeable and have the right optical properties to scatter light in a skin-like way. So for a while, finding the ideal material seemed like a materials science pipe dream.

“I think it’s just [about] getting a combination of all the things you want, and that’s never easy,” said Langer, who co-founded the company Living Proof as well as Olivo Laboratories, which is developing the technology.

But after a decade or so of research, during which the researchers built a library of more than 100 possible polymers, a team of researchers say it has finally designed a skin-like, silicone-based polymer. This material, which it calls a wearable cross-linked polymer layer, or XPL, is so elastic that it can return to its original shape after being stretched by more than 250%. This beats human skin, which can stretch 180% and recover, but also far outperforms currently used wound dressings such as sheets of silicone gel or films made of polyurethane.

The scientists performed several tests on human subjects to determine whether their material was safe and effective. For example, in one experiment, they applied XPL to the eye-bag area, where the steady compressive force exerted by the material tightened the sagging skin. A second experiment found that skin on the forearm that was stretched with a suction cup recovered faster than untreated skin did. A third test on the legs of volunteers who had moderately to severely dry skin found that XPL improved skin’s hydration, preventing water loss much better than skin treated with what they called “a cosmetically elegant, ‘high-end’ commercial moisturizer.”

“You hardly know that it’s on,” said Langer, who said he’d tried the second skin on himself. “It sort of conforms to the skin. You can’t really see it after a short period of time.”

Even for 16 hours and under sweaty conditions, the material held strong, the researchers said.

“The XPL remained intact following activities such as swimming, running and exposure to rain,” the study authors wrote.

The effect isn’t permanent and essentially only lasts while the second skin is on. But the potential applications are far-reaching, said Langer, who added that the clinicians on the study probably would be testing the material’s usefulness in treating eczema and other skin ailments.

“I’ll just be happy if it helps people,” Langer said.

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