Mussel Byssus Structure-Function and Fabrication as Inspiration for Biotechnological Production of Advanced Materials

Biotechnology offers an exciting avenue toward the sustainable production of high performance proteinaceous polymeric materials. In particular, the mussel byssus-a high performance adhesive bio-fiber used by mussels to cling on hard surfaces-has become a veritable archetype for bio-inspired self-healing fibers, tough coatings, and versatile wet adhesives. However, successful translation of mussel-inspired design principles into man-made materials hinges upon elucidating structure-function relationships and biological fabrication processes. This review provides a detailed survey of the state-of-the-art understanding of the biochemical structure-function relationships defining byssus performance with a particular focus on structural hierarchy and metal coordination-based cross-linking. The efforts to mimic the byssus in man-made materials are then discussed. While there has been a strong push to mimic the byssus via synthetic chemistry taking a reductionist approach, herein the focus is specifically on recent progress of biotechnology-based strategies that more closely approximate the biochemical complexity of the natural material. As an outlook, an overview of recent research toward understanding the natural byssus assembly process is provided, as processing remains a critical factor in achieving native-like properties.