title: Mechanical and structural contribution of non-fibrillar matrix in uniaxial tension: a collagen-agarose co-gel model.
abstract: The mechanical role of non-fibrillar matrix and the nature of its interaction with the collagen network in soft tissues remain poorly understood, in part because of the lack of a simple experimental model system to quantify these interactions. This study's objective was to examine mechanical and structural properties of collagen-agarose co-gels, utilized as a simplified model system, to understand better the relationships between the collagen network and non-fibrillar matrix. We hypothesized that the presence of agarose would have a pronounced effect on microstructural reorganization and mechanical behavior. Samples fabricated from gel solutions containing 1.0 mg/mL collagen and 0, 0.125, or 0.25% w/v agarose were evaluated via scanning electron microscopy, incremental tensile stress-relaxation tests, and polarized light imaging. While the incorporation of agarose did not dramatically alter collagen network morphology, agarose led to concentration-dependent changes in mechanical and structural properties. Specifically, resistance of co-gels to volume change corresponded with differences in fiber reorientation and elastic/viscoelastic mechanics. Results demonstrate strong relationships between tissue properties and offer insight into behavior of tissues of varying Poisson's ratio and fiber kinematics. Results also suggest that non-fibrillar material may have significant effects on properties of artificial and native tissues even in tension, which is generally assumed to be collagen dominated.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Spencer P
authors.initials: SP
authors.lastname: Lake
authors.forename: Victor H
authors.initials: VH
authors.lastname: Barocas
mesh_terms: D003094:Collagen / Q000737:chemistry* / Q000648:ultrastructure*; D003198:Computer Simulation; D055119:Elastic Modulus; D005109:Extracellular Matrix / Q000737:chemistry* / Q000648:ultrastructure*; D005782:Gels / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D012685:Sepharose / Q000737:chemistry* / Q000648:ultrastructure; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D005782:Gels; D003094:Collagen; D012685:Sepharose