Artificial Skin, by Katie Geldhart and Timothy Ma

Introduction

Artificial skin is the term used to describe any kind of material designed and used to replace naturally growing skin. The primary application of such materials right now revolves around treating individuals that have suffered severe tissue loss from disease or trauma (e.g. skin cancer, burns). Alternatively, artificial skin is now being used in some places to treat patients that suffer from foot ulcers [2][11]. Labs have also developed in vitro skin samples to be used for cosmetic and medical testing. This provides a cheaper and more ethical approach for testing surface reactions to topical treatments [1][11].

The most important goals of current artificial skin technologies are to provide protection from infection, dehydration, and protein loss after severe tissue damage. Each year, over 2 million people in the United States are treated for burns [2][11]. Artificial skin is employed to seal a wound quickly to minimize the amount of fluid lost by the patient and to limit bacterial intrusion. Integra is a brand of artificial skin commonly used in medical facilities today.

Overview of the Skin

A. Cross section of human skin.

Human skin is comprised of two primary layers, the dermis and the epidermis. The epidermis is the outermost layer and comprises of keratinocytes that vary in levels of differentiation. There are no blood vessels present in the epidermis which means nutrient transport occurs from the dermis below [2][11]. The dermis contains several structures important to skin function: hair follicles sweat and oil glands, and nerves are all found within the dermis [2][11]. Epithelial keratinocytes also originate from within this layer.

History of Skin Grafts

3000-2500BC, India: Skin is allegedly transplanted by Hindus from the buttocks to repair mutilated ears and noses.

1442, Italy: An allogenous skin graft was performed by Branca de Branca who used a man’s arm skin to transplant the nose of the man’s slave onto himself.

1597, Italy: Branca’s methods were published by Tagliacozzi.

1804, Italy: First successful autograph in sheep, done by Baronio.

1823, Germany: Full thickness autologous skin grafts were successfully performed by Bunger. Done by transplanting skin from the patient’s thigh to their nose, a procedure inspired by the original Indian records.

1869, Switzerland: First epidermic pinch graft by Reverdin.

1871, England: Pollock proposes skin grafts for burn treatment.

1875, Scotland: Full-thickness skin grafts become an official clinical practice.

1886, Germany: Thin split-thickness skin grafts used by Thierch.

1970’s, United States: Cryopreserved skin used for human allografts, viable epithelial sheets grown in vitro by Rheinwalk and Green.

1979, United States: Burke and Yannas successfully test the first artificial skin (Integra) on a patient [1][11].

1981, United States: Cultured epithelial grafts used in burn patients.

1998, United States: First tissue engineered skin (Apligraf) is approved by the FDA.

2001, United States: Dermagraft, Orcel, Composite Cultured Skin are FDA approved [4][11].

2002, United States: Integra is FDA approved for treatment of severe burns [4][11].

 All time points provided by reference [3]unless otherwise noted