Understanding the Healing Uses of Artificial Skin

Artificial skin is a substitute for human skin produced in the laboratory, typically used to treat severe burns.

Different types of artificial skin differ in their complexity, but all are designed to mimic at least some of the skin’s basic functions, which include protecting against moisture and infection and regulating body heat.

How Artificial Skin Works

Skin is primarily made of two layers: the uppermost layer, the epidermis, which serves as a barrier against the environment; and the dermis, the layer below the epidermis which makes up roughly 90 percent of the skin. The dermis also contains the proteins collagen and elastin, which help give the skin its mechanical structure and flexibility.

Artificial skins work because they close wounds, which prevents bacterial infection and water loss and helps the damaged skin to heal.

For example, one commonly used artificial skin, Integra, consists of an “epidermis” made of silicone and prevents bacterial infection and water loss, and a “dermis” based on bovine collagen and glycosaminoglycan.

The Integra “dermis” functions as an extracellular matrix—a structural support found between cells that helps regulate cell behavior—that induces a new dermis to form by promoting cell growth and collagen synthesis. The Integra “dermis” is also biodegradable and is absorbed and replaced by the new dermis. After several weeks, physicians replace the silicone “epidermis” with a thin layer of epidermis from another part of the patient’s body.

Uses of Artificial Skin

• Treating burns: Artificial skin is commonly used to treat burn injuries, especially if the patient does not have enough healthy skin that can be transplanted to the wound. In such cases, the body cannot generate skin cells quickly enough to heal the damaged skin, and the patient’s injury may become lethal due to significant fluid loss and infection. Artificial skin can thus be used to immediately close the wound and improve survival.
• Treating skin disorders: Some artificial skin products like Apligraf have been used to treat chronic wounds on the skin, such as ulcers, which are open wounds that heal very slowly. They may also be applied to skin disorders like eczema and psoriasis, which often span a large portion of the body and may benefit from artificial skins laden with medicine, which can easily wrap around the affected area.
• Research in consumer products and medicine: Aside from its uses in the clinical setting, artificial skin may also be used to model human skin for research. For example, artificial skin is used as an alternative to animal testing, which is often used to gauge how a cosmetics or medical product affects the skin. However, this testing may cause pain and discomfort to the animals and does not necessarily predict the response of human skin. Some companies like L’Oréal have already used artificial skin to test many chemical ingredients and products.
• Artificial skin may also simulate skin for other research applications, including how skin is affected by UV exposure and how chemicals in sunscreen and medicines are transported through skin.

Types of Artificial Skin

Artificial skins mimic either the epidermis or dermis, or both epidermis and dermis in a “full-thickness” skin replacement.

Some products are based on biological materials like collagen, or biodegradable materials not found in the body. These skins can also include a non-biological material as another component, such as Integra’s silicone epidermis.

Artificial skins have also been produced by growing sheets of skin live skin cells taken from the patient or other humans. One major source is the foreskins of newborns, taken after circumcision. Such cells often do not stimulate the body’s immune system—a property that allows fetuses to develop in their mother’s wombs without being rejected—and hence are much less likely to be rejected by the patient’s body.

How Artificial Skin Differs From Skin Grafts

Artificial skin should be differentiated from the skin graft, which is an operation in which healthy skin is removed from a donor and attached it to a wounded area. The donor is preferably the patient themself, but could also come from other humans, including cadavers, or from animals like pigs.

However, artificial skin is also "grafted" onto a wounded area during treatments.

Improving Artificial Skin for the Future

Though artificial skin has benefited many people, a number of drawbacks can be addressed. For example, artificial skin is expensive as the process to make such skin is complex and time-consuming. Furthermore, artificial skin, as in the case of sheets grown from skin cells, can also be more fragile than their natural counterparts.

As researchers continue to improve on these, and other, aspects, however, the skins that have been developed will continue to help save lives.

References

• Brohem, C., da Silva Cardeal, L., Tiago, M., Soengas, M., de Moraes Barros, S., Maria-Engler, S. “Artificial skin in perspective: concepts and applications.” Pigment Cell & Melanoma Research, 2011, vol. 24, no. 1, pp. 35-50, doi: doi: 10.1111/j.1755-148X.2010.00786.x.
• Companies are making human skin in labs to curb animal testing of products, Bob Woods, CNBC.
• Cooper, G. “Cell walls and the extracellular matrix.” In The Cell: A Molecular Approach. 2nd edition, 2000, Sunderland, MA, Sinauer Associates.
• Halim, A., Khoo, T., and Yussof, S. “Biologic and synthetic skin substitutes: An overview.” Indian Journal of Plastic Surgery, 2010, vol. 43, pp. S23-S28, doi: 10.4103/0970-0358.70712.
• Integra Dermal Regeneration Template.
• Jones, I., Currie, L., and Martin, R. “A guide to biological skin substitutes.” British Journal of Plastic Surgery, 2002, vol. 55, pp. 185-193, doi: 10.1054/hips.2002.3800.
• Schulz, J., Tompkins, R., and Burke, J. “Artificial skin.” Annual Review of Medicine, 2000, vol. 51, pp. 231-244, doi: 10.1146/annurev.med.51.1.231.
• ‘Second skin’ goes on over your skin to smooth your wrinkles, Ike Swetlitz, STAT.
• Tompkins, R., and Burke, J. “Progress in burn treatment and the use of artificial skin.” World Journal of Surgery, vol. 14, no. 6, pp. 819-824, doi: 10.1007/BF01670529.
• Varkey, M., Ding, J., and Tredget, E. “Advances in skin substitutes—Potential of tissue engineered skin for facilitating anti-fibrotic healing.” Journal of Functional Biomaterials, 2015, vol. 6, pp. 547-563, doi:10.3390/jfb6030547.
• Zhang, Z., and Michniak-Kohn, B. “Tissue engineered human skin equivalents.” Pharmaceutics, 2012, vol. 4, pp. 26-41, doi:10.3390/pharmaceutics4010026.