A cell culture medium and system are provided which eliminate or at least reduce the requirement for exogenous components such as serum and feeder cells. The cell culture medium comprises an IGF and vitronectin or fibronectin and, optionally an IGFBP, and is particularly suitable for propagating keratinocytes for subsequent use in skin growth and regeneration. This invention also relates to compositions and methods for skin growth and regeneration in situ, which utilize aerosol delivery of cultured keratinocytes.