Structure, extraction, processing, and applications of collagen as an ideal component for biomaterials - a review

Collagen with a multi-hierarchical architecture exhibits powerful biological performance, thus being developed in biomedical applications as a processing building block. The isolated collagen after extraction from biological tissues can be processed into various forms such as fibrils, scaffolds, membranes, microspheres, hydrogels, and sponges for further use in specific applications. This review briefly discusses the multi-hierarchical structure, powerful biological performances, extraction, and processing approaches of collagen as a natural biomaterial. The processing of collagen including dissolution, self-assembly, cross-linking, and electrospinning, is discussed to show more feasibility for specific applications of collagen composite biomaterials. Further emphasis is directed towards the biomedical applications of drug and gene delivery, as well as tissue repair involving bone, cartilage, vascular, and corneal, along with wound healing. Additionally, there is a focus on the development of flexible sensors and electronic skins (e-skins). Furthermore, the potential challenges and perspectives for the development of collagen-based biomaterials are proposed. In short, collagen-based biomaterials are expected to facilitate sustainable development and the next generation of advanced biomaterial applications. Graphical Abstract