Processing of Continuous Non‐Crosslinked Collagen Fibers for Microtissue Formation at the Muscle‐Tendon Interface

Abstract One of the main components of the extracellular matrix (ECM) in natural tissues is collagen. Therefore, there has been a strong focus on processing of collagen for biomaterials application in tissue engineering such as in anisotropic tissues like muscles and tendons. To achieve native‐like mechanical properties of the in vitro processed collagen, various crosslinking methods have been tested, but the used crosslinkers often do not yield sufficient mechanical properties or induce considerable inflammatory reactions. Here, good mechanical stability of collagen fibers is achieved by self‐assembly during wet‐spinning without the need of additional crosslinkers. The produced endless collagen fibers show fibril alignment within the fiber with a typical D‐band pattern and a periodicity of approximately 67 nm, which is unique for fibril‐forming collagens. Furthermore, the collagen fibers are processed into hierarchical assemblies using textile‐engineering techniques. The woven assemblies are shown to be excellent substrates for the formation of muscle microtissue with long, aligned, and contractile myofibers. Such constructs are highly important at the muscle‐tendon‐junction (MTJ) and therefore myoblasts and fibroblasts are co‐cultured to develop an MTJ‐model.