COLL 503 |
| Nianhuan Chen1, Marcel Benz1, Rafael Tadmor2, and Jacob Israelachvili3. (1) Department of Chemical Engineering, University of California, 3357 Engineering II, Santa Barbara, CA 93106, (2) Department of Chemical Engineering, Lamar University, Beaumont, TX 77710-0053, (3) Department of Chemical Engineering and Material Science, University of California, Santa Barbara, Santa Barbara, CA 93106 |
| The articular surfaces in synovial joints belong to the best known lubricating bearings and undergo minimal wear. Hyaluronic acid (HA) is a major component of synovial fluid and is believed to play a role in joint lubrication. Using a Surface Forces Apparatus we have measured the normal and shear forces between surfaces containing free, physically absorbed and chemically bound HA. Our results show that free and physisorbed HA fail as a lubricant when surfaces are pressed strongly together and/or sheared due to the squeezing out of the HA from between the surfaces. Chemically bound HA offers much better protection than adsorbed HA, it nonetheless is pushed out as the surfaces approach. On the other hand, the HA layer can remain between the surfaces after the crosslinking, and provides very good wear protection. However, coefficient of friction reaches values up to 0.3. Hyaluronan does not appear to be responsible for the great joint lubrication; It may be functioning as a protection of the articular cartilage surface. |
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“Smart” Polymers on Surfaces and Colloids
8:30 AM-11:30 AM, Thursday, April 1, 2004 Marriott -- Grand Ballroom J, Oral
Division of Colloid and Surface Chemistry |