The extracellular matrix (ECM) is an essential element for higher organisms to form cells, tissues, and organs; to control cell-cell connections and functions. The ECM also greatly affects several biological phenomena (such as development, aging, inflammation, wound healing, and immunity). Glycosaminoglycans (GAGs), such as chondroitin sulfate, hyaluronic acid and keratan sulfate, are major components of the ECM and play an important role. Analysis of glycosaminoglycan is very difficult, especially when performing in situ analysis of cells and tissues. Thus, antibodies are particularly important as detection tools.