Embryoid bodies, fluorescent light micrograph. Embryoid bodies (EBs) are aggregates of differentiating embryonic stem (ES) cells. They are formed when ES cells are cultured in suspension. As the cells mature there is an increase in cell number and complexity. ES cells are pluripotent, they are able to differentiate into any of the 200 hundred cells in the body. As the cells in the EBs differentiate they form the three germ layers, from which all tissues are formed. ES cells are a potential source of cells to repair damaged tissues in diseases such as Parkinson's and insulin-dependent diabetes.