6 From Basic Wound Healing to Modern Skin Engineering

The skin is our largest organ and it simultaneously fulfills many functions required in everyday life. The most important function of the skin is to act as a barrier between the body and the external environment. Many immune cells are also present in the skin to provide protection against invading micro-organisms. The skin is in addition an important participant in the physiological water homeostasis and it is one of the main ways the body regulates its temperature. Normal skin has sensation with protective value; a physical tensile capacity allowing for body mobility and it provides the external contour as well as the texture and the color of the exterior. Over the millennia mankind has been fascinated by the body’s ability to heal itself. Throughout history the main goal has always been to cover skin defects and to close wounds in order to protect the human body. Skin grafting and flap surgical procedures have been used in order to facilitate wound healing for thousands of years. Due to the advances in critical care and resuscitation, patients who, in the past, would have died in the acute phase are now surviving. Consequently there is a much greater need for high-quality skin substitutes. The clinical demand has driven newer technologies, building upon principles learned using cadaver and autografts, to the creation of engineered skin substitutes using living allograft cells as well as the combining of technologies to create composites – the most advanced products and at present the closest products to living skin. An autologous split thickness skin graft currently still remains superior to all commercially available skin substitutes with regards to its unique qualities. There are, however, situations where we prefer to use non-autologous substitutes, either because the patient may be too fragile for the added surgical trauma of harvesting split-skin grafts or due to the fact that there is not enough skin which could be harvested, for example, post-burn.