The vast family of products of the COL gene (collagens) is composed of several types of chains, interstitial collagens forming fibrils (types I, II, III and V) and basal membrane collagens (type IV). Each type of collagen has several isoforms. Collagens are fibrous extracellular matrix proteins with high tensile strength and are the main components of connective tissue, such as tendons and cartilage. All collagens contain a triple helix domain and often show lateral self-association to form complex connective tissues.

Type I collagen is the main structural component of the extracellular matrix (ECM) found in connective tissue and internal organs, but is most common in the dermis, tendons and bones. It is a 300 kDa molecule composed of two alpha1 chains and an alpha2 chain which spontaneously forms a triple helix scaffold at neutral pH and 37 ° C. This phenomenon can be exploited to promote cellular attachment, growth, differentiation , migration and tissue morphogenesis during development.