The MagDot is a dual-purpose reagent, it combines quantum dots and superparamagnetic iron oxide particles within the same nanoparticle. Cells labeled with MagDots targeting specific antigens will be both fluorescent and magnetic. Therefore, after labeling cells of interest, one can look at the feed to determine the percent positive fluorescently via flow cytometry, and then place the labeled cells in a magnetic separator and analyze both the magnetic (for the enrichment) and the nonmagnetic (for the depletion) of targeted cells without the need for further fluorescent labeling. The SK7 antibody conjugated to this MagDot recognizes the T-cell surface glycoprotein CD3 epsilon chain (CD3ɛ), also known as T-cell surface antigen T3/Leu-4 epsilon. CD3ɛ is a subunit of the TCR-CD3 cell surface receptor complex, which is expressed at the surface of mature T cells, NKT cells and thymocytes.