Scientists can promote induced pluripotent stem cell or iPS cell differentiation into various specialized cell types, including pancreatic beta cells, liver cells, and cardiomyocytes, using different methods. Cells are grown using different techniques, and differentiation is induced by adding specific growth factors to the cell culture medium in a particular sequence at specific times. In one method, the iPS cells are grown in a culture medium, where they form three-dimensional cell clusters called embryoid bodies or EBs that later form differentiated cells. For example, EBs differentiate into neurons when grown in a special culture medium supplemented with molecules, such as growth factors or vitamins, that trigger the neuronal differentiation pathway. This method sequentially transforms the EBs from pluripotent cells to neural progenitor cells and, finally, to terminally differentiated and active motor neurons. In another method, iPS cells are grown on artificial scaffolds that provide the extracellular matrix proteins for growth. The cells directly transform into specialized cells without forming the intermediate embryoid bodies.