Poster 1: Cell and Tissue Studies

Emily P. Lambeth; David L. Burris; Christopher Price

University of Delaware

Articular cartilage facilitates remarkably low friction coefficients in our joints1. Only recently has this lubricity been replicated on the benchtop, using a configuration that promotes tribological rehydration and synovial fluid2,3. Synovial fluid is composed of numerous molecules that may influence cartilage lubrication, including hyaluronic acid (HA)3,4. Here, our objective was to explore the effects of hydrodynamics and interstitial lubrication (ISL) and HA presence on cartilage friction. Osteochondral explants (19mm) were extracted from mature bovine femoral condyles2,3. All explants underwent loading and sliding preconditioning before undergoing “speed sweep” tests where sliding speed and lubricant were altered. In study 1, four increasing concentrations of HA (0 – 5mg/mL, 1.4MDa) were assessed, while in study 2, four increasing molecular weights of HA (0-1.4MDa, 3mg/mL) were utilized. As expected, the lowest observed equilibrium frictions occurred at sliding speeds >40mm/s, while peak frictions occurred at <5mm/s regardless of lubricant. Interestingly, peak and minimum frictions decreased with increasing HA concentration and molecular weight. These findings suggest that upon the sliding-dependent recovery of fluid load support and ISL, HA becomes a power synergistic lubrication partner, and that these benefits are HA concentration and molecular weight dependent.
References: [1] Linn J Biomech 1968; [2] Moore OA&C 2017; [3] Farnham Tribol Let 2021; [4] Fam Biorheol 2007.

Research Area: Cartilage