Articular cartilage is a low-friction, load-bearing tissue located at joint
surfaces. It experiences static and dynamic forces including shear,
compression and tension. We investigate the relationship between structure
and function by measuring the osmotic and mechanical properties in cartilage
layers as a function of the distance from the articular surface. Atomic
force microscopy is used to probe the mechanical properties at high spatial
resolution. The mechanical measurements are complemented by osmotic swelling
pressure observations made on the same samples using a novel tissue
osmometer. The results show that the osmotic modulus significantly depends
on the distance from the articular surface. Its value is highest in the deep
zone and lowest in the middle zone.