“Super melanin” heals skin injuries caused by sunburns and chemical burns

Imagine a skin cream that heals the damage that occurs throughout the day when your skin is exposed to the sun or environmental toxins. This is the potential of a biomimetic synthetic melanin developed by scientists at Northwestern University.

In a new study, scientists show that their synthetic melanin, mimicking natural melanin in human skin, can be applied topically to injured skin, where it accelerates wound healing. These effects occur both on the skin itself and systemically throughout the body.

When applied in a cream, synthetic melanin can protect skin from sun exposure and heal skin injured by sun damage or chemical burns, scientists said. The technology works by eliminating free radicals produced by injured skin, such as a sunburn. If left unchecked, free radical activity damages cells and can ultimately lead to skin aging and skin cancer.

Melanin in humans and animals provides pigmentation to the skin, eyes and hair. The substance protects your cells from sun damage by increasing pigmentation in response to sunlight – a process commonly known as tanning. This same pigment in your skin also naturally eliminates free radicals in response to harmful environmental pollution from industrial sources and automobile exhaust.

Daily injury to your skin

“People don’t view their daily lives as injuring their skin,” said co-corresponding author Dr. Kurt Lu, the Eugene and Gloria Bauer Professor of Dermatology at Northwestern University’s Feinberg School of Medicine and dermatologist at Northwestern Medicine. “If you walk barefaced in the sun every day, you experience a constant, low-intensity bombardment of ultraviolet light. This situation worsens during midday rush hours and during the summer season. We know that skin exposed to the sun ages compared to skin protected by clothing, which doesn’t show as much age.

Skin also ages due to chronological aging and external environmental factors, including environmental pollution.

“All of these skin insults lead to the formation of free radicals that cause inflammation and degrade collagen,” Lu said. “This is one of the reasons why older skin looks very different from younger skin. .”

When scientists created the synthetic melanin nanoparticles, they modified the structure of melanin to have a higher ability to scavenge free radicals.

“Synthetic melanin is able to scavenge more radicals per gram than human melanin,” said co-corresponding author Nathan Gianneschi, the Jacob and Rosaline Cohn Professor of Chemistry, Materials Science and Engineering, Biomedical Engineering and Pharmacology at Northwestern. . “It’s like super melanin. It is biocompatible, degradable, non-toxic and transparent when rubbed into the skin. In our studies, it acts as an effective sponge, removing harmful factors and protecting the skin.

Once applied to the skin, melanin remains on the surface and is not absorbed by the layers below.

“Synthetic melanin stabilizes and places the skin on a healing path, which we see both in the upper layers and throughout the body,” Gianneschi said.

Both Lu and Gianneschi are members of the Robert H. Lurie Comprehensive Cancer Center at Northwestern University.

Topical cream calms the immune system

The scientists, who have been studying melanin for nearly 10 years, first tested their synthetic melanin as a sunscreen.

“This protected the skin and skin cells from damage,” Gianneschi said. “Next, we wondered whether synthetic melanin, which mainly serves to absorb radicals, could be applied topically after skin injury and have a healing effect on the skin? It turns out it works exactly that way.

Lu envisions the synthetic melanin cream being used as a sunscreen booster for extra protection and as a moisturizer enhancer to promote skin repair.

“You can put it on before going out in the sun and after being exposed to the sun,” Lu said. “In both cases, we showed a reduction in skin damage and inflammation. You protect the skin and repair it simultaneously. It’s a continuous repair.

The cream could also potentially be used for blisters and open wounds, Lu said.

Gianneschi and Lu found that synthetic melanin cream, by absorbing free radicals after an injury, calmed the immune system. The stratum corneum, the outer layer of mature skin cells, communicates with the epidermis below. It is the surface layer that receives signals from the body and the outside world. By calming the destructive inflammation on this surface, the body can begin to heal instead of becoming even more inflamed.

“The epidermis and upper layers are in communication with the whole body,” Lu said. “This means that stabilizing these upper layers can lead to an active healing process.”