US Patent 8481308 Methods for culturing undifferentiated cells using sustained release compositions

Methods for culturing undifferentiated mammalian cells, such as stem and progenitor cells, are provided. The methods involve incubating the cell in the presence of a sustained release composition containing at least one growth factor, wherein the sustained release composition continuously releases the growth factor(s), and wherein the presence of the sustained level of growth factor maintains the cell in an undifferentiated state.