title: Nanomechanics of opposing glycosaminoglycan macromolecules.
abstract: In this study, the net intermolecular interaction force between a chondroitin sulfate glycosaminoglycan (GAG)-functionalized probe tip and an opposing GAG-functionalized planar substrate was measured as a function of probe tip-substrate separation distance in aqueous electrolyte solutions using the technique of high resolution force spectroscopy. A range of GAG grafting densities as near as possible to native cartilage was used. A long-range repulsive force between GAGs on the probe tip and substrate was observed, which increased nonlinearly with decreasing separation distance between probe tip and substrate. Data obtained in 0.1 M NaCl was well predicted by a recently developed Poisson-Boltzmann-based theoretical model that describes normal electrostatic double layer interaction forces between two opposing surfaces of end-grafted, cylindrical rods of constant volume charge density and finite length, which interdigitate upon compression. Based on these results, the nanomechanical data and interdigitated rod model were used together to estimate the electrostatic component of the equilibrium modulus of cartilage tissue, which was then compared to that of normal adult human ankle cartilage measured in uniaxial confined compression.
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, MIT 13-4022, Cambridge, MA 02139, USA.
authors: Joonil
authors: J
authors: Seog
authors: Delphine
authors: D
authors: Dean
authors: Bernd
authors: B
authors: Rolauffs
authors: Tao
authors: T
authors: Wu
authors: Jan
authors: J
authors: Genzer
authors: Anna H K
authors: AH
authors: Plaas
authors: Alan J
authors: AJ
authors: Grodzinsky
authors: Christine
authors: C
authors: Ortiz
mesh_terms: D001696:Biomechanical Phenomena / Q000379:methods; D002358:Cartilage, Articular / Q000737:chemistry* / Q000502:physiology*; D003198:Computer Simulation; D004548:Elasticity; D006025:Glycosaminoglycans / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D046911:Macromolecular Substances / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods; D008956:Models, Chemical; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D055672:Static Electricity; D013314:Stress, Mechanical
chemical_list: D006025:Glycosaminoglycans; D046911:Macromolecular Substances