The method was developed with Miltenyi Biotec's MACS system, which uses superparamagnetic nanoparticles and columns.
Miltenyi sells microbeads which are magnetic nanoparticles conjugated to antibodies which can be used to target specific cells.
In the Assisted Reproductive Technology (ART) field, the apoptotic spermatozoa (those who are programmed to die) are bind in the Annexin V(a membrane apoptotic marker) with a specific monoclonal antibodies which are conjugated a magnetic microsphere.
The MACS method allows cells to be separated by using magnetic nanoparticles coated with antibodies against a particular surface antigen.
After incubating the beads and cells, the solution is transferred to a column in a strong magnetic field.
Moreover, it enables early detection of sperm which initiate apoptosis, although they may show an adequate appearance and motility.