Articular cartilage is a biological tissue with ultra-low friction properties and excellent impact resistance, and extensive research is being conducted to explore the engineering applications of these properties. One of the ultra-low friction mechanisms of cartilage is proposed to be the hydration lubrication derived from proteoglycan(PG)-hyaluronic acid(HA) aggregates on the surface layer of cartilage. In order to gain further insight into the contribution of the hydration layer in a wide range of lubrication modes, PG-mixed agarose gel and HA solutions as lubricants were prepared based on cultured cartilage tissue model. A lubricant containing PG added to HA solutions was also prepared for comparison. The effects of PG-HA aggregates were evaluated by velocity-dependent friction tests and viscosity measurements using a rheometer. The results indicated that PGsol-HA aggregates promoted the transition of lubrication modes under high HA concentration conditions due to the shear thickening. In contrast, PGgel-HA aggregates were suggested to promote the transition of lubrication modes under low HA concentration conditions by locally altering the properties of the polymer on the gel surface.
SATO et al. (Wed,) studied this question.