Collagen is Type I soluble, salt free component of skin, bone, tendon, and other fibrous connective tissues. Type I collagen differs from other collagens by their low lysine hydroxylation and low carbohydrate composition. It breaks down metabolically in the body to release N-telopeptide, which is the N-terminus of collagen. There is also C-telopeptide, which is presumably the C-terminus. N-telopeptide is released in urine, and its detection in diagnostic tests is used to screen for osteoporosis.

• Soluble in 0,075 M sodium citrate, dilute acetic acid and opalescent viscous solution at 5 mg/ml in H₂O
• Suitable for gel formation, platelet aggregation, collagenase activity

It has been used as a scaffold for the growth of stem cells in vitro, in a wide variety of biomaterial engineering studies. It may be used in research of Idiopathic pulmonary fibrosis (IPF) and in studies on the effect of endoplasmic reticulum (ER) stress from IPF on myofibroblastic differentiation of lung fibroblasts. In acidic solution produces three dimensional scaffolding useful in bioengineering and cell culture applications where biomaterials are needed to replace native collagen extracellular matrices.