Compositions and methods for inducing tissue differentiation and growth within a localized area of application in humans or other animals are provided. Compositions comprising a biological or pharmacologically active agent such as Insulin-like Growth Factor-1 (IGF-1) and sustained-release nanoparticle formulations comprising IGF-1 and a matrix forming component such as hyaluronan for use in skin repair and regeneration are provided. Nanoparticles of the invention activate endogenous stem cells in the local area of administration to produce new dermal cells and tissues.
