Stem cells are unspecialized cells that have two defining properties: the ability to differentiate into other cells and the ability to self-regenerate. Self-regeneration is the ability of stem cells to divide and produce more stem cells2.A totipotent stem cell can develop into all cell types. A pleuripotent stem cell can develop into cells from all three germinal layers. Multipotent Stem Cells can be divided into many cells types. Unipotent stem cells can develop into one type of cell type.
Stem cells have three main properties.
Plasticity is a newly recognized ability of stem cells to expand their potential beyond the tissue from which they are derived.
Transdifferentiation is the direct conversion of one cell type to another,
cell fusion: ES cells can fuse in vitro with neuronal cells and with hematopoietic stem cells and the nucleus was reprogrammed instead of transdifferentiating.
Stem cells use in different ways including
1) Functional Genomic studies
2) Cell-based therapy
3) Study of biological processes
4) Drug discovery and development