title: Osmotic pressure induced tensile forces in tendon collagen.
abstract: Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100 MPa, largely surpassing those of about 0.3 MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone.
authors.affiliation: Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors.forename: Admir
authors.initials: A
authors.lastname: Masic
authors.affiliation: Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors.forename: Luca
authors.initials: L
authors.lastname: Bertinetti
authors.affiliation: Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Schuetz
authors.affiliation: Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, MIT, Cambridge, Massachusetts 02139, USA.
authors.forename: Shu-Wei
authors.initials: SW
authors.lastname: Chang
authors.affiliation: Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors.forename: Till Hartmut
authors.initials: TH
authors.lastname: Metzger
authors.affiliation: Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, MIT, Cambridge, Massachusetts 02139, USA.
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Buehler
authors.affiliation: Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Fratzl
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000473:pathology; D003094:Collagen / Q000737:chemistry*; D005260:Female; D056004:Molecular Dynamics Simulation; D009119:Muscle Contraction; D009995:Osmosis; D009997:Osmotic Pressure; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman; D013314:Stress, Mechanical; D013696:Temperature; D013710:Tendons / Q000473:pathology*; D013718:Tensile Strength; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction; D014965:X-Rays
chemical_list: D014867:Water; D003094:Collagen