The dermal equivalent is an in vitro

In vitro

In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

 model of the dermal layer

Dermis

The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...

 of skin. It is constructed by seeding dermal fibroblast

Fibroblast

A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing...

s into a collagen

Collagen

Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

 gel. This gel may then be allowed to contract as a model of wound contraction. This collagen gel contraction assay

Collagen gel contraction assay

The collagen gel contraction assay is a type of wound contraction. It is performed using the dermal equivalent model, which consists of dermal fibroblasts seeded into a collagen gel....

 may be used to screen for treatments which promote or inhibit contraction and thus affect the development of a scar

Scar

Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

. Other cell types may be incorporated into the dermal equivalent to increase the complexity of the model. For example, keratinocytes may be seeded on the surface to create a skin equivalent

Skin equivalent

A skin equivalent is an in vitro skin model using to conduct experiments on processes involving the skin, such as wound healing and keratinocyte migration. It is a more complex form of the dermal equivalent ....

, or macrophages may be incorporated to model the inflammatory phase of wound healing

Wound healing

Wound healing, or cicatrisation, is an intricate process in which the skin repairs itself after injury. In normal skin, the epidermis and dermis exists in a steady-state equilibrium, forming a protective barrier against the external environment...

.