In early May, a team of researchers at the Massachusetts Institute of Technology (MIT) unveiled a cross-linked polymer layer (XPL) gel that could treat skin conditions such as eczema and psoriasis, which can both cause very itchy, dry skin. The gel, which seals in moisture as well as thick ointments, does not wash off. Instead, XPL can remain for up to 24 hours or until you remove it.
For those with psoriasis and eczema, the skin fails to act as a barrier between the body and the rest of the world. According to study co-author Barbara A. Gilchrest, acting president of the American Skin Association, the polymer could serve to boost this barrier through a new layer of “skin.” She added that the material could mimic skin better than ointment.
Moreover, researchers found that they can alter the structure of the chemical chains to create a more permeable gel that could one day help deliver medication directly to the skin. XPL could offer an effective and long-lasting alternative to traditional ointments, many of which are greasy and rub off soon after application. In addition, the elasticity of the polymer blend could prove to be more effective than traditional wound dressings.
In addition, the polymer could have cosmetic applications, such as reducing wrinkles and tightening skin.
In an article published in Nature Materials, the researchers offered insight into the development of XPL, which they said can simulate the look and feel of real skin, as well as protect it from harm. The team partnered with medical developer Olivo Laboratories and the company Living Proof to create and patent this innovative gel.
Creating a Second Skin
Under the guidance of head researcher and inventor Robert Langer, the MIT researchers initiated their project by perusing the list of chemicals that the U.S. Food and Drug Administration (FDA) approved as safe for human use. In particular, they were searching for any chemical that contained the silicon-oxygen atom chain known as siloxane. Once they found over 100 of these approved chemicals, researchers began testing and altering the chain length of each one to see which would best achieve the desired effects. Primarily, they wanted to create a material that naturally stretched and conformed to the shape of skin while also maintaining the same visual appearance.
Numerous other researchers previously attempted to accomplish this goal, but the team from MIT was the first to uncover the correct polymer chain. Langer and his researchers discovered that they were able to use polysiloxane as a base chemical, thereby creating a polymer synthesis that seamlessly imitates skin. The arrangement, which they dubbed XPL, has since earned the nickname “second skin” for its unique and revolutionary properties.
The key lies in the cross-linking system of MIT’s XPL gel. Researchers developed a two-step process that helps to reinforce the mechanical structure of the gel, much like that involved in creating tires, when vulcanization is used to strengthen the bare rubber. A clear polymer, the XPL gel is spread on the skin. Since this liquid has weak chemical chains, researchers developed a second product that lies atop this first layer. The platinum-based cream is the catalyst that triggers the cross-linking reaction in the polymer that creates a strong, highly stretchable bond on the skin. MIT researchers designed this product to cure quickly and without applied light or heat, which makes it both effective and easy to use. In fact, both gels take only 3 minutes to cure completely when combined.
One of the most remarkable effects of the XPL gel is its transparency. The second layer incorporates particles that scatter any light that hits them. This creates an effect that is far removed from the appearance of today’s “transparent” bandages, which often give off a shiny and wrinkled appearance that still make them noticeable atop the skin. On the other hand, XPL is virtually invisible in both its look and feel.
Promising Laboratory Tests
MIT has tested this “second skin” in several experiments that analyzed its various capabilities. In one such test, 25 volunteers used XPL on the baggy skin beneath their eyes. Remarkably, it created a tightened veneer atop the sagging skin, achieving the same result as the standard lower lid blepharoplasty surgical procedure. With XPL, the participants’ skin also showed the ability to better bounce back into place when pinched and stretched more than 70 percent further than normal skin.
Outside of its visual effects, this test revealed the incredible durability of the polymer gel. In fact, only two of the 25 participants experienced noticeable edges on patches of the gel after 16 hours of continued use. XPL even remained intact after subjects swam, washed their skin, and sweated. Even with this durability, you can easily remove the polymer by using makeup remover or simply peeling it away from the skin.
While it is not a life-saving medical innovation, its potential for applications in medicine may someday make XPL an instrumental material. After additional testing, MIT researchers hope to receive marketing approval from the FDA and to formally introduce their “second skin” to consumers.