Microscale Tribological Response of Human Osteoarthritic Articular Cartilage under the Boundary Lubrication of Hyaluronic Acid

Abstract

Microscale frictional response by atomic force microscopy (AFM) can provide an opportunity to measure the final equilibrium of the cartilage frictional coefficient in the absence of interstitial fluid pressurization. In this study, we examined the effect of hyaluronic acid (HA) concentrations on the boundary lubrication of human osteoarthritis (OA) cartilage. Articular cartilage samples were obtained from human femoral heads with normal and advanced–stage OA cartilage. The tests samples were submerged in the lubricants of PBS and HA 1.0, 3.0, and 5 mg/ml. The microscale frictional coefficient and surface roughness of the OA cartilage was measured by AFM using triangular silicon(nitride cantilevers attached a polystyrene spherical tip. The results demonstrated HA concentrations to have ineffective boundary(lubricating ability in the normal cartilage. On the other hand, for the advanced–stage OA cartilage, HA played an important role in enhancing the boundary(lubricating ability due to the adsorption of HA molecules on the damaged cartilage surface. The microscale frictional response of the advanced–stage OA cartilage was independent on the on the HA concentrations. This suggests that some factors of the articular cartilage change during the progression of OA, which can trigger the boundary(lubricating ability of HA.