title: Cooperative behavior of a sacrificial bond network and elastic framework in providing self-healing capacity in mussel byssal threads.
abstract: The dissipative and self-healing properties of mussel byssal threads are critical for their function as anchoring fibers in wave-battered habitats and central to their emergence as an exciting model system for bio-inspired polymers. Much is now understood about the structure-function relationships defining this remarkable proteinaceous bio-fiber; however, the molecular mechanisms underlying the distinctive tough, viscoelastic and self-healing behavior are still unclear. Here, we investigate elastic and dissipative contributions from the primary load-bearing proteins in the distal region of byssal threads (the preCols) using X-ray diffraction (XRD) combined with in situ tensile testing. Specifically, we identified cross β-sheet structure in the preCol flanking domains that functions as an elastic framework, providing hidden length. Dissipative behavior was associated with a strain-rate dependent phase transition of a sacrificial network stabilized by strong, reversible cross-links. Based on these findings, we posit a new model for byssal thread deformation and self-healing.
authors.affiliation: Dept. of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam 14424, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Reinecke
authors.affiliation: Dept. of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam 14424, Germany.
authors.forename: Luca
authors.initials: L
authors.lastname: Bertinetti
authors.affiliation: Dept. of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam 14424, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Fratzl
authors.affiliation: Dept. of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam 14424, Germany. Electronic address: matt.harrington@mpikg.mpg.de.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Harrington
mesh_terms: D000818:Animals; D001704:Biopolymers / Q000737:chemistry* / Q000378:metabolism; D049872:Bivalvia / Q000737:chemistry; D000072757:Protein Conformation, beta-Strand; D011506:Proteins / Q000737:chemistry* / Q000648:ultrastructure; D012984:Software; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
chemical_list: D001704:Biopolymers; D011506:Proteins
keywords: Beta sheet; Collagen; Mussel byssal thread; Self-healing; X-ray diffraction