Stem cells can develop into many different types of other cells, such as bone, muscle and skin. Until recently, totipotent stem cells were only found in embryos, but new research suggests they may be available from some adult tissues as well. Embryonic stem cells are the subject of ongoing federal policy debates because of ethical questions surrounding their use. Stem cells from blood or bone marrow, however, fall outside of this debate. Sorting stem cells and other rare cell types is a challenge because they are often difficult to distinguish from neighboring cells.
Stem cells account for only a tiny fraction of cells found in bone marrow or other tissues.
Chalmers' magnetic cell sorter selects desired cell types by measuring how they move through a magnetic field. Each cell type moves at a known rate, making it possible to identify them and pull them aside. Before the cell sorter can do its work, researchers attach magnetic particles to antibodies that selectively bind to the cells of interest. The tagged cells are then subjected to a strong magnetic field. Chalmers' cell sorter could be less expensive and easier to maintain than flow cytometers, the most popular devices for cell sorting.