Collagen containing tissues as skin, tendon and bone have been used as biomaterial 3000 years ago by surgeons of India for rhinoplastics and earlobe reconstruction. Sushruta, the most famous Indian surgeon described in detail the methodology of surgical interventions, using skin autografts of the cheek to remodel the nose. Today, collagen based biomaterials are manifold available to be used in surgery and by dentists and recently, purified collagen based materials became again important as scaffold material in tissue engineering.
Almost all of these materials are manufactured from tissues of mammals, mainly skin, tendon, pericard or intenstine. Processing of collagen from tissues to be used as biomaterials always comprise intensive washing steps mostly in aqueous solutions changing pH between 1 and 13, combined with the addition of different inorganic and organic salts, surfactants, solvents, and further additives. Often it is aimed to separate as much non collagenous material as possible while saving the collagen structure or derivatives in a defined state.
It is the focus of this contribution to summarize the different materials structures of tissue, cell-free tissue, minced tissue, thermally treated tissue and gelatine, to mention how they are affected by processing and how to rebuild again new structures. It will be shown, which process act on which level of the hierarchical structure of collagen and how it is possible to uncouple and selectively affect the different structural levels.