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1 Department of Chemistry, Technical University of Denmark 2 KTH - Royal Institute of Technology 3 Centre for oil and gas – DTU, Center, Technical University of Denmark 4 SP Technical Research Institute of Sweden 5 SP Technical Research Institute of Sweden
It is becoming increasingly clear that the outstanding lubrication of synovial joints is achieved by a sophisticated hierarchical structure of cartilage combined with synergistic actions of surface-active components present in the synovial fluid. In this work we focus on the association of two components of the synovial fluid, hyaluronan and dipalmitoyl phosphatidyl choline (DPPC), in bulk solution and at interfaces. We demonstrate that hyaluronan associates with DPPC vesicles and adsorbs to supported DPPC bilayers. The association structures formed at the interface are sufficiently stable to allow sequential adsorption of DPPC and hyaluronan, whereby promoting the formation of thick composite layers of these two components. The lubricating ability of such composite layers was probed by the AFM colloidal probe technique and found to be very favorable with low friction coefficients and high load bearing capacity. With DPPC as the last adsorbed component, a friction coefficient of 0.01 was found up to pressures significantly above what is encountered in healthy synovial joints. Hyaluronan as the last added component increases the friction coefficient to 0.03 and decreases the load bearing capacity somewhat (but still above what is needed in the synovial joint). Our data demonstrate that self-assembly structures formed by hyaluronan and phospholipids at interfaces are efficient aqueous lubricants, and it seems plausible that such self-assembly structures contribute to the exceptional lubrication of synovial joints. © 2013 American Chemical Society.
Biomacromolecules, 2013, Vol 14, Issue 12, p. 4198-4206
Bioengineering; Materials Chemistry; Polymers and Plastics; Biomaterials; Association structures; Colloidal probe techniques; Friction coefficients; Hierarchical structures; Load-bearing capacity; Low friction coefficients; Self-assembly structure; Sequential adsorption; Bearing capacity; Body fluids; Friction; Joints (anatomy); Lubrication; Phospholipids; Self assembly; Hyaluronic acid; dipalmitoylphosphatidylcholine; hyaluronic acid; phospholipid; adsorption; article; atomic force microscopy; cartilage; colloidal probe technique; friction; joint; light scattering; lipid bilayer; lubrication; molecular biology; molecular interaction; priority journal; procedures; quartz crystal microbalance; surface property; synovial fluid; 1,2-Dipalmitoylphosphatidylcholine; Adsorption; Animals; Biomechanical Phenomena; Colloids; Humans; Hyaluronic Acid; Lipid Bilayers; Lubricants; Microscopy, Atomic Force; Solutions; Synovial Fluid
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