Confocal-FRAP Analysis of ECM Molecular Interactions

Extracellular matrices (ECM) contain a mixture of fibrillar and nonfibrillar macromolecular components, which together form a composite structure (1 –3 ). It is the ECM that defines the architecture, the form, and the biomechanical properties of different tissues (4 ,5 ). Among the nonfibrillar macromolecules, the highly charged proteoglycans and hyaluronan are major components that occur at high concentration and greatly influence the movement of solutes and water between the tissue and the circulation, and control the access to cells of nutrients, metabolites, growth factors, and chemokines (6 –7 ). This local environmental regulation may have important consequences on cellular functions, especially in tissues with large dense ECMs, such as articular cartilage.