The present invention provides a method that maintains chondrocyte
phenotype during serial expansion by culturing a population of
chondrocytes in a defined serum-free culture medium containing cytokines
and on a substrate that is modified by covalent attachment of hyaluronic
acid. The underlying principle is to maintain native chondrocyte
phenotype by growing the dissociated chondrocytes on a substrate modified
by covalent attachment of hyaluronic acid to retain native chondrocyte
morphology and function. Chondrocyte expanded in this manner can be used
in various medical applications to repair cartilaginous tissues that have
been injured by trauma or disease. This substratum provides a
microenvironment that more closely mimics that of native articular
cartilage, thereby promoting chondrogenesis in a predictable manner.