Cartilage is a complex, specialized tissue comprising cells (chondrocytes) embedded in a dense collagenous matrix. Anatomically, one can distinguish a number of zones through the depth of the tissue from the surface to the bone. Both cell density and arrangement and matrix density vary across the different zones, and the matrix itself is inhomogeneous even within intercellular spaces. We are developing experimental procedures to obtain co-localized chemical composition and mechanical property maps using FTIR and AFM indentation experiments. Cartilage sections, a few microns in thickness are sectioned from different zones of mouse cartilage for study. Both healthy and osteoarthritic cartilage sections are examined in detail. Chemical composition and mechanical properties maps thus obtained are correlated across each zone and through the cartilage depth. The result will be a comprehensive view of variations throughout the tissue and point to the changes associated with disease and aging.
