How does artificial skin work

The epidermis is comprised of keratinocytes of varying levels of differentiation. As can be seen in the figure, the epidermis contains no blood vessels meaning transport of nutrients to the epidermis occurs from the dermis below [2].

While the primary role of the epidermis is to provide an outer protective layer, the dermis contains several structures important to skin function.

Hair follicles, sweat and oil glands, and nerves are all found within the dermis [2]. Additionally, epithelial keratinocytes originate from within this layer. Current artificial skin techniques for burn treatment typically provide a scaffolding to promote regeneration of the dermis.

An autograft is then performed to replace the epidermis. Alternatively, artificial skin has been made to replace both layers of the skin as in the case of certain small wound and foot ulcer treatments. Skin grafts are required for patients with skin damage that is too significant for self-repair. As stated before, one of the primary requirements for artificial skin is for the treatment of severe burn victims.

There are three levels of burns; 1st, 2nd, and 3rd degree burns. A first degree burn only affects the epidermis whereas a second degree burn extends downward into the dermis. Third degree burns go through the epidermis, dermis, and the hypodermis.

In either of these scenarios a skin graft will most likely be required for the area to heal. Skin grafts are also often done on patients with ulcers, skin loss from cancer removal, and plastic surgery [1]. The skin required for a skin graft can be obtained from three sources; the patient themselves autograft , another human allograft , or from animals such as pigs or cows xenografts [2]. Allografts and xenografts can only be used as temporary wound coverings as they are typically rejected within 7 to 10 days or 3 to 5 days respectively [2].

There are two primary types of autografts; split-thickness grafts and full-thickness grafts. Split thickness grafts take only a part of the dermis and the epidermis from the donor site to transplant to the wound site.

This is beneficial in that the donor site remains somewhat intact however, because the transplanted tissue does not contain all of the original glands and hair follicles, split-thickness grafts typically leave noticeable differences in skin color and texture.

Full—thickness skin grafts take out the entire dermis and epidermis layers from the donor site but they look more natural in the wound site and often provide improved skin flexibility compared to the STSG. For this reason, FTSG are commonly used for hand and facial skin graft procedures.

There are several draw backs to autographs, the first of which is the removal of donor skin from another part of the body. Additionally, when skin is removed from one area to place in another, both areas must be given treatment to allow proper healing.

Even more concerning however is the lack of availability of these donor skin sites for patients suffering from extremely large areas of skin loss. This is where artificial skin has truly made a difference. Since , a total of 4 skin repair devices have been FDA approved. Dermagraft and Apligraf FDA approved are used for the treatment of foot ulcers and contain living cells.

Collagen is part of the structural scaffolding in mammals analogous to cellulose in plants that allows tissues to maintain their shape. The collagen-GAG combination "makes a simple chemical analog of the matrices in our own tissues," he explained. Surgeons can implant this material, temporarily covered by a thin layer of silicone that protects the area from infectious agents and excessive moisture loss.

The collagen-GAG material has pores with carefully controlled diameters that permit cells to grow through the scaffold, which is eventually broken down and dissolved by enzymes. Cells synthesize a new dermis at the same time that the scaffold is being broken down. Epidermis then grows naturally over the new dermis unless the wound area is especially large, in which case the surgeon does an autograft of epidermis-a much less problematic procedure than grafting dermis, because epidermis is one-tenth as thick and is constantly being shed and regrown.

Patients end up almost completely free of the devastating scars that result from ungrafted burns scar tissue is weaker and less flexible than skin or the somewhat lesser but still significant disfigurement from autografts.

The new skin also grows as the patients do, an important consideration for burned children. The only limitation is that patients with large grafts must avoid strenuous exercise in the sun, because the newly synthesized dermis does not have the original dermis's sweat glands and hair follicles. But the technique goes a long way toward solving "the short-term problem of survival and the long-term problem of quality of life," said Professor Yannas, who holds appointments in the Departments of Mechanical Engineering and Materials Science and Engineering.

He is a consultant for Integra LifeSciences Corp. In addition to several students, Professor Yannas' collaborator has been Dr. John F. Burke pioneered development of the procedure for preparing wounds for collagen-GAG grafts by removing all traces of dead tissue. He also educated the MIT team as to the specific requirements of wound treatment for massively burned patients, as well as being the first surgeon to use the new treatment with humans.

Professor Yannas's work has focused on optimizing the pore size and rate of breakdown of the material, as well as its chemical composition. List of Partners vendors. Share Flipboard Email. Alane Lim. Science Expert. Alane Lim holds a Ph. She has published numerous peer-reviewed journal articles on nanotechnology and materials science. Updated March 30, Featured Video. Cite this Article Format. Lim, Alane. Understanding the Healing Uses of Artificial Skin.

The Structure of the Integumentary System. Biology Prefixes and Suffixes: Derm- or -Dermis. Learn About the Body's Connective Tissue. Biology Prefixes and Suffixes: hem- or hemo- or hemato-.