Engineering a Leather Biomaterial

Tissue engineering combined with synthetic biology aims to build controlled, functional, and multicellular biological structures. Here we demonstrate the application of these principles to produce novel biomaterials of animal origin, namely leather. A leather-like material does not require the complete anatomical skin of the animal; rather it requires a collagenous extracellular matrix (ECM). To construct this matrix in vitro, bovine fibroblasts are grown over 18 days, producing self-assembled ECM tissue sheets. Upon harvesting, the sheets are briefly seeded with another cell layer, then wrapped around a plastic mandrel with five additional sheets to form a multilayered tissue structure approximately 15 layers deep. This thick tissue construct is cultured for an additional three weeks to allow for layer-to-layer attachment and fusion via additional collagen synthesis and assembly. The resulting tissue is an approximately 20 x 5 cm, 0.5-1 mm thick sheet. Harvested samples proceed through proprietary tanning chemistry to produce finished cultured leather. The final tensile strength is 10-15 MPa, elongation at break approximately 30%, and samples are hydrothermally stable up to 95C, which is comparable to animal-derived leather. Our novel method of leather production has several unique features compared to traditional leather: products are prepared with minimal inorganic waste; leathers are not size-constrained; the entire process is performed in a closed and controlled environment; and novel material properties can be engineered.